induction heating system that allows an alternating magnetic field to cross a blade surface and meth

专利摘要:
INDUCTION HEATING UNIT CONTROL UNIT, INDUCTION HEATING SYSTEM, AND METHOD TO CONTROL INDUCTION HEATING UNIT. The present invention relates to the control unit of an induction heating unit controls the AC power output to a heating coil of an induction heating unit of the transverse type which allows an alternating magnetic field to cross a blade surface. of a conductive blade being loaded to inductively heat the conductive blade. The control unit includes: a magnetic energy recovery switch that supplies AC power to the heating coil; a frequency determining unit that determines an output frequency in response to at least one of relative permeability, resistivity, and blade thickness of the conductive blade; and a door control unit that controls a switching operation of the magnetic energy recovery switch based on the output frequency determined by the frequency determining unit.
公开号:BR112012016028B1
申请号:R112012016028-1
申请日:2010-11-22
公开日:2020-10-27
发明作者:Kazuhiko Fukutani；Yasuhiro Mayumi；Toshiya Takechi；Kenji Umetsu
申请人:Nippon Steel Corporation；
IPC主号:

专利说明:

FIELD OF THE INVENTION
[001] The present invention relates to a control unit for an induction heating unit, an induction heating system, and a method for controlling the induction heating unit. Particularly, the present invention is suitable to be used to make an alternating magnetic field cross a conductive blade in a substantially orthogonal manner to inductively heat the conductive blade.
[002] Priority is claimed for Japanese Patent Application No. 2009-283255, filed on December 14, 2009, the content of which is incorporated into this document by reference. DESCRIPTION OF RELATED TECHNIQUE
[003] In conventional techniques, for example, an induction heating unit has been used when heating a conductive blade such as a steel blade is transported through a manufacturing line. The induction heating unit is provided with a heating coil, and heats the conductive blade using eddy current induced by the heating coil. In this induction heating unit, eddy current is produced for the conductive blade by an alternating magnetic field (AC magnetic field) generated by the heating coil, Joule heat is generated in the conductive blade due to the eddy current. As an example of the induction heating unit, a transverse type induction heating unit is disclosed. In the transverse type induction heating unit, the alternating magnetic field is applied to the conductive blade in a manner that crosses a blade surface of the conductive blade, which is an object to be heated, to be substantially orthogonal to it.
[004] As a method for controlling the transverse type induction heating unit, a technique disclosed in Patent Citation 1 can be exemplified. In Patent Citation 1, a capacitor is provided in parallel to the heating coil that makes up the induction heating unit, the heating coil and the capacitor make up a parallel resonance circuit, and power is supplied to the heating coil via a parallel resonance type inverter. PATENT CITATION
[005] Patent Citation 1 Unexamined Japanese Patent Application, First Publication No. 2002-313547 SUMMARY OF THE INVENTION Problems to be solved by the invention
[006] However, when the heating coil of the induction heating unit is viewed from a power supply unit (power supply circuit) of the induction heating unit, the inductance varies in response to the transmission speed of the blade conductive which is an object to be heated by the induction heating unit (in the description below, this inductance is referred to as apparent inductance when necessary). Specifically, when the transmission speed of the conductive blade becomes fast (or slow), the apparent inductance becomes small (or large).
[007] However, in the technique disclosed in Patent Citation 1, the heating coil and capacitor make up the parallel resonance circuit. Therefore, when the apparent inductance varies, the frequency of the energy, which is supplied to the heating coil, also varies. For example, when the transmission speed of the conductive blade becomes fast and thus the apparent inductance becomes small, the frequency of the energy supplied to the heating coil increases. In this way, when the frequency of the energy supplied to the heating coil increases, the temperature in the vicinity of an end part (edge) of the conductive blade in the direction of the blade width becomes greater than in the vicinity of the central part of the conductive blade in the direction of the blade width. Therefore, there is an issue where a conductive blade temperature distribution in the direction of the blade width may be non-uniform.
[008] As described above, in conventional techniques, in a case where the conductive blade is heated using the transversal type induction heating unit, there is a problem in which as the transmission speed of the conductive blade varies, the temperature distribution of the conductive blade in the direction of the blade width becomes uneven.
[009] The present invention was made considering this problem, and an objective of the present invention is to perform a temperature distribution that is more uniform than in conventional techniques avoiding that the temperature distribution of the conductive blade in the direction of the blade width is not uniform even when the transmission speed of the conductive blade varies in a case where the conductive blade is heated using a transversal type induction heating unit. Methods to Solve the Problem
[0010] (1) A control unit of an induction heating unit according to an aspect of the present invention controls the AC power output to a heating coil of an induction heating unit of the transverse type which allows an alternating magnetic field crosses a blade surface of a conductive blade that is being charged to inductively heat the conductive blade. The control unit includes: a magnetic energy recovery switch that supplies AC power to the heating coil, a frequency determination unit that determines the output frequency in response to at least one of relative permeability, resistivity, and thickness of conductive blade blade; and a door control unit that controls a switching operation of the magnetic energy recovery switch based on the output frequency determined by the frequency determining unit.
[0011] (2) In the control unit of an induction heating unit according to (1), the frequency determining unit can obtain attribute information that specifies the relative permeability, resistivity, and blade thickness of the conductive blade , and you can select a frequency that corresponds to the attribute information obtained as the output frequency with reference to a table in which the relative permeability, resistivity, and blade thickness of the conductive blade, and the frequency are correlated with each other and are registered in advance.
[0012] (3) The control unit of an induction heating unit according to (1) or (2) may additionally include: an output current determination unit that determines an output current value in response to at least one of relative permeability, resistivity, and blade thickness of the conductive blade; a current measurement unit that measures an alternating current flowing into the induction heating unit; and a power supply unit that supplies DC power to the magnetic energy recovery switch and sets an alternating current that is measured by the current measurement unit to the output current value that is determined by the output current, in which the magnetic energy recovery switch can be supplied with DC power by the power supply unit and can supply AC power to the heating coil.
[0013] (4) In the control unit of an induction heating unit according to (3), the output current determination unit can obtain attribute information that specifies the relative permeability, resistivity, and blade thickness of the conductive blade, and you can select a current value that corresponds to the attribute information obtained as the output current value with reference to a table in which the relative permeability, resistivity, and blade thickness of the conductive blade, and the current value they are correlated with each other and are registered in advance.
[0014] (5) The control unit of an induction heating unit according to any one of (1) to (4) may additionally include an output transformer that is arranged between the magnetic energy recovery switch and the induction heating unit, reduces the AC voltage that is provided by the magnetic energy recovery switch, and supplies the reduced AC voltage to the heating coil.
[0015] (6) In the control unit of an induction heating unit according to any one of (1) to (5), the magnetic energy recovery switch can include first and second AC terminals that are connected to a end and the other end of the heating coil, respectively, first and second DC terminals that are connected to an output terminal of the power supply unit, a first semiconductor switch of the reverse conductivity type that is connected between the first AC terminal and the first DC terminal, a second semiconductor switch of the reverse conductivity type that is connected between the first AC terminal and the second DC terminal, a third semiconductor switch of the reverse conductivity type that is connected between the second AC terminal and the second DC terminal, a fourth reverse conductivity type semiconductor switch that is connected between the second AC terminal and the first DC terminal, and a capacitor which is connected between the first and second DC terminals, the first semiconductor switch of the reverse conductivity type and the fourth semiconductor switch of the reverse conductivity type can be connected in series in such a way that the driving directions at the time of a shutdown become opposite to each other, the second semiconductor switch of the reverse conductivity type and the third semiconductor switch of the reverse conductivity type can be connected in series in such a way that the driving directions at the time of shutdown become opposite to each other. another, the first semiconductor switch of the reverse conductivity type and the third semiconductor switch of the reverse conductivity type can both have the same driving direction at the time of shutdown, the second semiconductor switch of the reverse conductivity type and the fourth semiconductor switch of the reverse conductivity type can both have the same direction of co nduction at shutdown, and the door control unit can control a time of the switching operation of the first and third semiconductor switches of the reverse conductivity and a time of the switching operation of the second and fourth semiconductor switches of the type of reverse conductivity based on the output frequency which is determined by the frequency determining unit.
[0016] (7) An induction heating system according to another aspect of the present invention allows an alternating magnetic field to cross a blade surface of a conductive blade that is being charged to inductively heat the conductive blade. The induction heating system includes: the control unit of an induction heating unit as defined in any one of (1) to (6); a heating coil that is arranged facing the blade surface of the conductive blade; a core around which the heating coil is wound; and a shield plate that is arranged facing a region that includes an edge of the conductive blade in the width direction and is formed by a conductor that has a relative permeability of 1.
[0017] (8) In the induction heating system according to (7), the shielding plate may have a lowered part.
[0018] (9) In the induction heating system according to (8), the shielding plate can be arranged in such a way that a region, which is closer to the edge of the conductive blade than a region in which a current Foucault flow that flows to the conductive blade becomes maximum, and the lowered part is turned towards each other.
[0019] (10) A method for controlling an induction heating unit in accordance with yet another aspect of the present invention controls AC power, which is supplied to a heating coil of an induction heating unit of the transverse type which allows an alternating magnetic field to cross a blade surface of a conductive blade being charged to inductively heat the conductive blade. The method includes: supplying AC power to the heating coil through a magnetic energy recovery switch; determining an output frequency in response to at least one of relative permeability, resistivity, and blade thickness of the conductive blade; and controlling a switching operation of the magnetic energy recovery switch based on the output frequency that is determined.
[0020] (11) In the method for controlling an induction heating unit according to (10), the output frequency can be determined by obtaining attribute information that specifies the relative permeability, resistivity, and blade thickness of the conductive blade , and selecting a frequency that corresponds to the attribute information obtained as the output frequency with reference to a table in which the relative permeability, resistivity, and blade thickness of the conductive blade, and the frequency are correlated with each other and are recorded in advance.
[0021] (12) The method for controlling an induction heating unit according to (10) or (11) may additionally include: determining an output current value in response to at least one of relative permeability, resistivity, and blade thickness of the conductive blade; measure an alternating current flowing to the induction heating unit; and providing DC power, which is required to set an alternating current that is measured to the output current value that is determined, for the magnetic energy recovery switch.
[0022] (13) In the method for controlling an induction heating unit according to (12), the output current value can be determined by obtaining attribute information that specifies the relative permeability, resistivity, and blade thickness of the conductive blade, and selecting a current value that corresponds to the attribute information obtained as the output current value with reference to a table in which the relative permeability, resistivity, and blade thickness of the conductive blade, and the current value are correlated with each other and are registered in advance.
[0023] (14) In the method for controlling an induction heating unit according to any of (10) to (13), an AC voltage that is supplied by the magnetic energy recovery switch can be reduced by an output transformer, and reduced AC voltage can be supplied to the heating coil.
[0024] (15) In the method for controlling an induction heating unit according to any one of (10) to (14), the magnetic energy recovery switch can include first and second AC terminals that are connected to a end and the other end of the heating coil, respectively, first and second DC terminals that are connected to an output terminal of the power supply unit, a first semiconductor switch of the reverse conductivity type that is connected between the first AC terminal and the first DC terminal, a second semiconductor switch of the reverse conductivity type that is connected between the first AC terminal and the second DC terminal, a third semiconductor switch of the reverse conductivity type that is connected between the second AC terminal and the second DC terminal, a fourth semiconductor switch of the reverse conductivity type that is connected between the second AC terminal and the first DC terminal, and a capacitance or that is connected between the first and second DC terminals, the first semiconductor switch of the reverse conductivity type and the fourth semiconductor switch of the reverse conductivity type can be connected in series in such a way that the driving directions at the time of a shutdown become opposite to each other, the second semiconductor switch of the reverse conductivity type and the third semiconductor switch of the reverse conductivity type can be connected in series such that the driving directions at the time of shutdown become opposite one the other, the first semiconductor switch of the reverse conductivity type and the third semiconductor switch of the reverse conductivity type can both have the same driving direction at shutdown, the second semiconductor switch of the conductivity type reverse and the fourth semiconductor switch of the reverse conductivity type can both have the same direction of conduction at shutdown, and AC power can be supplied to the heating coil by controlling a switching time of the first and third semiconductor switches of the reverse conductivity type and a switching time of the second and fourth semiconductor switches of the reverse conductivity type based on the output frequency that is determined. Effects of the Invention
[0025] According to the control unit of an induction heating unit according to the aspect of the present invention, the switching operation of the magnetic energy recovery switch is controlled based on the frequency in response to at least one of relative permeability, resistivity, and blade thickness of the conductive blade being charged, and the AC power of this frequency is supplied by the magnetic energy recovery switch. Therefore, the AC energy of the frequency that corresponds to the attribute of the conductive blade being charged can be applied to the heating coil without being subject to a restriction with respect to an operation with a resonant frequency. Therefore, it is possible to prevent the temperature distribution of the conductive blade in the direction of the blade width from being uneven even when a transmission speed of the conductive blade varies in a case where the conductive blade is heated using an induction heating unit of the type transversal. In addition, AC power with frequency in response to the attribute of the conductive blade being charged can be supplied to the heating coil regardless of operating conditions, so that the induction heating control can be performed relatively simple and safe. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Figure 1 is a side view illustrating an example of a schematic configuration of a continuous annealing line of a steel sheet according to a first embodiment of the present invention.
[0027] Figure 2A is a longitudinal sectional view illustrating an example of a configuration of an induction heating unit according to the first embodiment of the present invention.
[0028] Figure 2B is a longitudinal sectional view showing an example of the configuration of the induction heating unit according to the first embodiment of the present invention.
[0029] figure 2C is a partial perspective view illustrating an example of the configuration of the induction heating unit according to the first embodiment of the present invention.
[0030] figure 3 is a view illustrating an example of a configuration of an upper side of the heating coil and a lower side of the heating coil according to the first embodiment of the present invention.
[0031] Figure 4 is a view illustrating an example of a configuration of an induction heating unit control unit according to the first embodiment of the present invention.
[0032] Figure 5 is a view that illustrates an example of a relationship between a voltage Vc at both ends of a capacitor in a MERS, an IL current flowing to the induction heating unit, and an operating state of a semiconductor switch according to the first embodiment of the present invention.
[0033] Figure 6A is a graph that illustrates the relationship between frequency and temperature with respect to the transport speed of the blade, when energy is supplied to the induction heating unit using the control unit according to the first modality of present invention and a steel strip is heated.
[0034] Figure 6B is a graph that illustrates the relationship between frequency and temperature with respect to the transport speed of the blade, when power is supplied to the induction heating unit using a parallel resonance type inverter in a conventional technique and the steel strip is heated.
[0035] Figure 7 is a view that illustrates an example of a configuration of a control unit of an induction heating unit according to a second embodiment of the present invention.
[0036] Figure 8A is a longitudinal sectional view illustrating an example of a configuration of an induction heating unit according to a third embodiment of the present invention.
[0037] Figure 8B is a longitudinal sectional view illustrating an example of the configuration of the induction heating unit according to the third embodiment of the present invention.
[0038] Figure 8C is a partial perspective view illustrating an example of the configuration of the induction heating unit according to the third embodiment of the present invention.
[0039] Figure 9A is a view illustrating an example of a shielding plate configuration in accordance with the third embodiment of the present invention.
[0040] Figure 9B is a schematic view illustrating an example of an eddy current flowing through a steel strip and the shield plate in accordance with the third embodiment of the present invention.
[0041] Figure 9C is a schematic view illustrating an example of a magnetic field that is generated by eddy current according to the third embodiment of the present invention.
[0042] Figure 10A is a view that illustrates an example of a temperature distribution of a conductive blade, which is heated by the induction heating unit, in the direction of the blade width, in a case where the shield plate is used. according to the third embodiment of the present invention.
[0043] Figure 10B is a view that illustrates an example of a temperature distribution of a conductive blade, which is heated by the induction heating unit, in the direction of the blade width, in a case where a shield plate according with the first embodiment of the present invention is used. DETAILED DESCRIPTION OF THE INVENTION
[0044] Hereinafter, modalities of the present invention will be described with reference to the attached figures. In each of the following modalities, a description will be made with respect to an example in which a transversal type induction heating unit and a control unit thereof are applied to a continuous annealing line of a steel sheet in a line manufacturing. In addition, in the following description, "induction heating unit of the transversal type" will be referred to simply as "induction heating unit" when necessary. In addition, unless specifically specified, with respect to steel blade attributes (steel strip), ambient temperature values (eg 25 ° C) will be used. First modality
[0045] First, a first embodiment of the present invention will be described. Schematic Configuration of Continuous Annealing Line
[0046] Figure 1 shows a side view illustrating an example of a schematic configuration of a continuous annealing line of a steel blade.
[0047] In figure 1, the continuous annealing line 1 includes a first container 11, a second container 12, a third container 13, a first seal roller assembly 14, a transport unit 15, a second roller assembly seal 16, a gas supply unit 17, rollers 19a to 19u, an induction heating unit 20, and a control unit 100 of the induction heating unit. In addition, the induction heating unit 20 and the control unit 100 of the induction heating unit comprise an induction heating system.
[0048] The first seal roller assembly 14 carries (feeds) a steel strip 10 into the first container 11 while shielding the first container 11 from external air. The steel strip 10 transported into the first container 11 by the first seal roller assembly 14 is transported into the second container 12 by the rollers 19a and 19b into the first container 11. The steel strip 10 transported into the second container 12 is transported back into the first container 11 by the rollers 19g and 19h at the same time as it is heated by the induction heating unit 20 which is arranged on both an upper and lower side of a horizontal part of the second container 12 (from steel strip 10 being loaded). Here, the induction heating unit 20 (heating coil thereof) is electrically connected to the control unit 100 of the induction heating units, and AC power is supplied to the induction heating unit 20 from the control unit. 100 of the induction heating unit. An alternating magnetic field, which crosses a blade surface of the steel strip 10 in a substantially orthogonal manner, is generated by the AC energy, and thus the steel strip 10 is heated inductively. In addition, details of a configuration of the induction heating unit 20 will be described later. Additionally, in the following description, “electrical connection” will simply be referred to as “connection” when necessary.
[0049] The steel strip 10 which is returned into the first container 11 is transported to the transport unit 15 by the rollers 19c to 19f after passing through an immersion and slow cooling stage. The steel strip 10 transported to the transport unit 15 is transported to the third container 13 by the rollers 19i and 19j. The steel strip 10 transported to the third container 13 is transported at the same time as it is moved in a vertical up and down manner by the rollers 19k to 19u and is rapidly cooled in the third container 13.
[0050] The second set of sealing roller 16 forwards the steel strip 10, which is quickly cooled in this way, to a subsequent process while shielding the third container 13 from external air.
[0051] For the “first container 11, the second container 12, the third container 13, and the transport unit 15” that make up a “steel strip transport path 10” described above, non-oxidizing gas is supplied by the gas supply unit 17. Additionally, the first container 11, the second container 12, the third container 13, and the transport unit 15 are maintained in a non-oxidizing gas atmosphere by the “first seal roller set 14 and the second set of sealing roller 16 ”that shields the external side (external air) and the internal side (the internal side of the continuous annealing line 1). Induction heating unit configuration 20
[0052] Figures 2A to 2C show views that illustrate an example of an induction heating unit configuration.
[0053] Specifically, figure 2A shows a view that illustrates an example of the induction heating unit 20 according to this modality, which is seen from a side direction of a line, and is a longitudinal section view that is cut along along the longitudinal direction (the vertical direction in figure 1) of the steel strip 10. In figure 2A, the steel strip 10 is carried towards the left (reference to an arrow pointing from the right side to the left side in figure 2A) . Additionally, figure 2B shows a longitudinal sectional view showing an example of the induction heating unit 20 according to this embodiment, which is seen from a direction A-A 'in figure 1 (which is a view downstream in the direction blade transport). In figure 2B, the steel strip 10 is transported from the bottom direction to the front direction. Additionally, in figures 2A and 2B, the dimensions [mm] are also shown. Additionally, figure 2C shows a partial perspective view illustrating part of an example of the induction heating unit 20 according to this embodiment. In figure 2C, a lower right region shown in figure 2B (region surrounded by a dashed line in figure 2B) is viewed from above from an upper side of the steel strip 10. However, in figure 2C, the second container 12 is omitted for ease of understanding the positional relationship between a shield plate 31 and the steel strip 10.
[0054] In figures 2A to 2C, the induction heating unit 20 includes an inductor on the upper side 21 and an inductor on the lower side 22.
[0055] The upper side inductor 21 includes a core (magnetic core) 23, an upper side heating coil 24, and shield plates 31a and 31c. The core 23 can be configured by stacking a plurality of electric steel sheets.
[0056] The heating coil on the upper side 24 is a conductor that is wound on the core 23 through a slot (here, a lowered part of the core 23) of the core 23, and is a coil in which the number of turns is “ 1 ”(single call back). In addition, as shown in figure 2A, the top side heating coil 24 has a part in which the shape of the longitudinal section thereof is a hollow rectangle. A cooling water tube is connected to an end face of the hollow part of the hollow rectangle. The cooling water supplied by the cooling water pipe flows to the hollow part of the hollow rectangle (the inner side of the heating coil on the upper side 24) and in this way the inductor on the upper side 21 is cooled. In addition, the shield plates 31a and 31c are attached to the lower surface (slot side) of the core 23.
[0057] Similar to the upper side inductor 21, the lower side inductor 22 is also provided with a core (magnetic core) 27, a heating coil on the lower side 28, and shield plates 31b and 31d.
[0058] Similar to the heating coil on the upper side 24, the heating coil on the lower side 28 is a conductor that passes through a slit in the core 27 and is wound in the core 27, and is a coil in which the amount lap time is “1” (single lap call). In addition, similarly to the upper side heating coil 24, the lower side heating coil 28 has a part in which a shape of a longitudinal section thereof is a hollow rectangle. A cooling water tube is connected to an end face of the hollow part of the hollow rectangle, and the cooling water can be made to flow into the hollow part of the hollow rectangle. Additionally, the shield plates 31b and 31 d are installed on the upper surface (slot side) of the core 27.
[0059] Additionally, a face of the coil (face in which a loop is formed and through which a line of magnetic force penetrates) of the heating coil of the upper side 24 of the inductor of the upper side 21, and a face of the coil of the coil heating elements on the lower side 28 of the lower side inductor 22 are facing each other with the steel strip 10 interposed between them. In addition, the surfaces of the shield plates 31a to 31d are directed towards the end parts (edges) of the steel strip 10 in the direction of the width of the blade. To satisfy this positional relationship, the upper side inductor 21 is provided on an upper side (in the vicinity of the upper surface of a horizontal part of the second container 12) compared to the steel strip 10, and the lower side inductor 22 is provided in a lower side (in the vicinity of the lower surface of the horizontal part of the second container 12) compared to the steel strip 10. In this embodiment, the shield plates 31a to 31 d are copper plates that have a flat surface (reference to figure 2C) . The shield plates 31a to 31 d weaken the degree of electromagnetic coupling between the upper side heating coil 24 and the steel strip 10, and the degree of electromagnetic coupling between the lower side heating coil 28 and the steel strip 10, thereby preventing the vicinity of the edges of the steel strip 10 in the direction of the width of the steel from being overheated.
[0060] In this way, the upper side inductor 21 and the lower side inductor 22 are different from each other in the position to be arranged, but have the same configuration as each other. Additionally, in this configuration, since an alternating magnetic field generated from the heating coil crosses the conductive blade 10 over its entire width, the entire width of the conductive blade 10 can be heated.
[0061] Figure 3 shows a view illustrating an example of a configuration of the heating coil on the upper side 24 and the heating coil on the lower side 28. Additionally, the arrows shown in figure 3 illustrate an example of a direction in which a current flows.
[0062] As shown in figure 3, the top side heating coil 24 includes copper tubes 41a and 41b, and a copper bus bar (connection plate) 42b that is connected to the end sides of the base of the copper tubes 41a and 41b. In addition, the bottom side heating coil 28 includes copper tubes 41c and 41 d, and a copper bus bar 42f which is connected to the base end sides of the copper tubes 41c and 41 d.
[0063] An output terminal of the control unit 100 of the induction heating unit is connected to one end (front end side of the copper pipe 41a) of the top side heating coil 24 through the copper bus bar 42a . On the other hand, one end (front end side of copper tube 41c) of the bottom heating coil 28 is connected to the other end (front end side of copper tube 41b) of the top heating coil 24 through copper bus bars 42c to 42e. In addition, the other output terminal of the control unit 100 of the induction heating unit is connected to the other end (front end side of the copper pipe 41 d) of the bottom heating coil 28 via the copper bus bars 42i, 42h, and 42g.
[0064] As described above, the top side heating coil 24 and the bottom side heating coil 28 are connected in series to the control unit 100 of the induction heating unit by combining copper tubes 41a to 41 of the bars copper bus 42a to 42i, thus forming coils in which the number of turns is "1". Here, the direction (in figure 3, a clockwise rotation) of one revolution of a current flowing through the heating coil on the upper side 24 is the same as the direction of one revolution of a current flowing through the heating coil. bottom side heating 28.
[0065] In addition, as described later, the control unit 100 of the induction heating unit supplies AC power to the heating coil on the upper side 24 and the heating coil on the lower side 28 of the induction heating unit 20. Therefore , in figure 3, the control unit 100 of the induction heating unit is indicated as an AC power source.
[0066] Additionally, here, to illustrate a configuration of the heating coil on the upper side 24 and the heating coil on the lower side 28 in an easy manner, the copper tubes 41a to 41 of the copper bus bars 42a to 42i are connected in a manner as shown in figure 3. However, to wrap the heating coil on the upper side 24 and the heating coil on the lower side 28 in cores 23 and 27, respectively, it is necessary that the copper pipes 41a to 41 d pass through (be fixed a) Through the slots in cores 23 and 27. Therefore, in reality, copper bus bars 42a to 42g are installed in copper tubes 41a to 41 d in different parts of the parts where the copper 41a to 41 d are installed in cores 23 and 27. Control Unit Configuration 100 of Induction Heating Unit
[0067] Figure 4 shows a view illustrating an example of a configuration of the control unit 100 of the induction heating unit. In addition, in the following description, “control unit of the induction heating unit” is referred to simply as “control unit” when necessary.
[0068] In Figure 4, control unit 100 includes an AC power source 160, a rectifier unit 110, a reactor 120, a bi-directional magnetic energy recovery current switch (MERS; Magnetic energy recovery switch) 130 , a port control unit 140, an output current determination unit 150, a current transformer 170, and a frequency determination unit 180. Here, current transformer 170 is used as a current measurement unit which measures the value of an alternating current flowing into the induction heating unit. Additionally, in the following description, “magnetic energy recovery switch” is referred to as “MERS” when necessary.
[0069] In figure 4, the AC power source 160 is connected to an input terminal of rectification circuit 110. One end of reactor 120 is connected to one end of rectification circuit 110 on an output side, and a terminal DC c of the MERS 130 is connected to the other end of the rectifying circuit 110. The other end of the reactor 120 is connected to a DC b terminal of the MERS 130. The rectifying circuit 110 rectifies the AC power supplied from the AC power source. 160 and applies DC power to MERS 130 through reactor 120. Rectifying circuit 110 is configured using, for example, a thyristor. As described above, in this embodiment, for example, a power supply unit is performed using the AC 160 power source and rectification circuit 110. This power supply unit is a unit that provides DC power described later for the terminals DC bec and MERS 130 in figure 4. Therefore, a DC power source such as a battery that has a current control function can be used as the power supply unit. Configuring the MERS 130
[0070] From now on, an example of a MERS 130 configuration will be described.
[0071] The MERS 130 converts DC energy, which is input through the rectifier circuit 110 through the reactor 120, to AC energy according to a method described later, and supplies the AC energy to the induction heating unit 20.
[0072] In figure 4, MERS 130 includes a bridge circuit that is configured using the first to fourth semiconductor switches of the type of reverse conductivity 131 to 134, and a capacitor C that has a polarity. This capacitor C is connected between the DC b and c terminals of the bridge circuit, and a positive (+) electrode of capacitor C is connected to the DC b terminal.
[0073] The other end of reactor 120 is connected to terminal DC b, and the other end of rectifying circuit 110 on the output side is connected to terminal DC c. In addition, one end (copper bus bar 42a) and the other end (copper bus bar 42g) of the induction heating unit 20 are connected to the AC terminals a and d (reference to figure 3), respectively.
[0074] The bridge circuit of the MERS 130 includes a first path L1 that reaches the terminal CA d through the terminal AC a through the terminal CC b, and a second path L2 that reaches the terminal AC d through the terminal AC a through the terminal CC c . The first semiconductor switch of the reverse conductivity type 131 is connected between the AC terminal d and the DC terminal b, and the fourth semiconductor switch of the reverse conductivity type 134 is connected between the DC terminal b and the AC terminal a. In addition, the second semiconductor switch of the reverse conductivity type 132 is connected between the AC terminal d and the DC terminal c, and the third semiconductor switch of the reverse conductivity type 133 is connected between the DC terminal c and the AC terminal a. In this way, the first and second semiconductor switches of the reverse conductivity type 131 and 132 are connected in parallel, and the third and fourth semiconductor switches of the reverse conductivity type 133 and 134 are connected in parallel. In addition, the first and fourth semiconductor switches of the reverse conductivity type 131 and 134 are connected in series, and the second and third semiconductor switches of the reverse conductivity type 132 and 133 are connected in series.
[0075] Each of the first to fourth semiconductor switches of the reverse conductivity type 131 to 134 allows a current to flow in one direction at the time of a shutdown in which a connected signal is not input to a port terminal of the same, and allows a current to flow in both directions at the time of an activation when the on signal is input to the gate terminal. That is, semiconductor switches of the reverse conductivity type 131 to 134 allow a current to flow in only one direction between a source terminal and a drain terminal at the time of shutdown, but allows a current to flow in both directions between the source terminal and the drain terminal at the time of activation. In addition, in the following description, “a forward direction in which each of the semiconductor switches of the reverse conductivity type 131 to 134 allows a current to flow at the time of shutdown” is also referred to as “a forward switching direction” when necessary. In addition, "a forward direction in which each of the semiconductor switches of the reverse conductivity type 131 to 134 does not allow current to flow at the time of shutdown" is also referred to as "a reverse switching direction" when necessary. In addition, in the following description, "a connection direction with respect to the bridge circuit in the forward switching direction and in the reverse switching direction" is also referred to as "a switching polarity" when necessary.
[0076] In addition, each of the semiconductor switches of the reverse conductivity type 131 to 134 is arranged to satisfy the switching polarity as described below. The first semiconductor switch of the reverse conductivity type 131 and the second semiconductor switch of the reverse conductivity type 132, which are connected in parallel, have opposite switching polarities. Similarly, the third semiconductor switch of the reverse conductivity type 133 and the fourth semiconductor switch of the reverse conductivity type 134, which are connected in parallel, have opposite switching polarities. In addition, the first semiconductor switch of the reverse conductivity type 131 and the fourth semiconductor switch of the reverse conductivity type 134, which are connected in series, have opposite switching polarities. Similarly, the second semiconductor switch of the reverse conductivity type 132 and the third semiconductor switch of the reverse conductivity type 133, which are connected in series, have opposite switching polarities. Therefore, the first semiconductor switch of the reverse conductivity type 131 and the third semiconductor switch of the reverse conductivity type 133 have the same switching polarity as each other. Similarly, the second semiconductor switch of the reverse conductivity type 132 and the fourth semiconductor switch of the reverse conductivity type 134 have the same switching polarity as each other. In addition, the switching polarity of the first and third semiconductor switches of the reverse conductivity type 131 and 133 is opposite to that of the second and fourth semiconductor switches of the reverse conductivity type 132 and 134.
[0077] Additionally, with respect to the switching polarities shown in figure 4, the switching polarity of the first and third semiconductor switches of the reverse conductivity type 131 and 133, and the switching polarity of the second and fourth semiconductor switches of the type of reverse conductivity 132 and 134 can be inverse to each other.
[0078] In addition, several configurations can be considered with respect to the first to fourth semiconductor switches of the reverse conductivity type 131 to 134, but in this embodiment, the first to the fourth semiconductor switches of the reverse conductivity type 131 to 134 are configured through a parallel connection between semiconductor switches S1 to S4 and diodes D1 to D4, respectively. That is, each of the first to fourth semiconductor switches of the reverse conductivity type 131 to 134 includes a diode (which corresponds to one between diodes D1 to D4) and a semiconductor switch (which corresponds to one between switches semiconductor S1 to S4) which is connected to the diode in parallel.
[0079] In addition, the respective port terminals G1 to G4 of semiconductor switches S1 to S4 are connected to port control unit 140. A on signal, which allows semiconductor switches S1 to S4 to be connected, is input for gate terminals G1 to G4 of port control unit 140 as a control signal for MERS 130. In a case where the on signal is input, semiconductor switches S1 to S4 enter a on state, and can allow a current to flow in both directions. However, in a case where the on signal is not input, semiconductor switches S1 to S4 go into an off state, and cannot allow current to flow in any direction. Therefore, when semiconductor switches S1 to S4 are turned off, a current can flow only in the direction of direction (forward direction) of diodes D1 to D4 that are connected in parallel to semiconductor switches S1 to S4.
[0080] Additionally, the semiconductor switches of the reverse conductivity type included in the MERS 130 are not limited to the first to the fourth semiconductor switches of the reverse conductivity type 131 to 134. That is, any semiconductor switch of the reverse conductivity type is preferable as long as this switch has a configuration capable of presenting the operation described above. For example, semiconductor switches of the reverse conductivity type may have a configuration using a switching element such as a power MOSFET and a reverse conductivity GTO thyristor, or may have a configuration in which a semiconductor switch such as a IGBT and a diode are connected in parallel.
[0081] Additionally, from now on, a description will be made replacing the switching polarity of the first to the fourth semiconductor switches of the type of reverse conductivity 131 to 134 with the polarity of the diodes D1 to D4. A forward switching direction (forward direction in which current flows at the time of shutdown) is a driving direction (forward direction) of each of the diodes D1 to D4, and a reverse switching direction (forward direction where a current does not flow at the time of shutdown) is a non-conduction direction (reverse direction) of each of the diodes D1 to Additionally, the conduction directions between diodes (D1 and D2, or D3 and D4) connected in parallel are opposite to each other, and the conduction direction between diodes (D1 and D4, or D2 and D3) connected in series are opposite one the other. In addition, the driving directions of diodes D1 and D3 are the same over and over. Similarly, the driving directions of diodes D2 and D4 are the same over and over. Therefore, the conduction direction of diodes D1 and D3 and the conduction direction of diodes D2 and D4 are opposite to each other. In addition, the driving directions of semiconductor switches S1 to S4 and diodes D1 to D4 are determined with a direction of a current flowing into the induction heating unit 20 taken as a reference. Operation of the MERS 130
[0082] Figure 5 shows a view that illustrates an example of a relationship between a voltage Vc at both ends of a capacitor C of the MERS 130, an IL current flowing to the induction heating unit 20, and a state of operation of semiconductor switches S1 to S4.
[0083] In figure 5, for a period when a waveform appears on one side indicated as “port S1-S3”, switches S1 and S3 are in a connected state, and semiconductor switches S2 and S4 are in an off state. Additionally, for a period when a waveform appears on one side indicated as “port S2-S4”, semiconductor switches S2 and S4 are in a switched-on state, and switches S1 and S3 are in a switched-off state. For a period when a waveform does not appear on either side of “port S1-S3” or “port S2-S4”, all semiconductor switches S1 to S4 are in an off state. In this way, when the semiconductor switch S1 is turned on (off), the semiconductor switch S3 is turned on (off), and therefore the semiconductor switches S1 and S3 operate together with each other. Similarly, when the semiconductor switch S2 is turned on (off), the semiconductor switch S4 is turned on (off), and therefore the semiconductor switches S2 and S4 operate together with each other. Hereinafter, an example of operation of the MERS 130 will be described with reference to figures 4 and 5.
[0084] As shown in figure 5, an initial stage of a period A is a dead time that accompanies a switching operation, and for this dead time, not only the semiconductor switches S1 and S3, but also the semiconductor switches S2 and S4 are turned off. During this dead time, a current flows through the path of diode D4 -> capacitor C diode D2, and therefore charging of capacitor C begins. As a result, the voltage Vc at both ends of capacitor C is high, and therefore the current IL (absolute value of it) flowing into the induction heating unit 20 decreases. When the semiconductor switches S2 and S4 are turned on (at the same time as the semiconductor switches S1 and S3 are turned off) before the charging of capacitor C is completed, a current flows through a path of the semiconductor switch S4 and the diode D4 capacitor C semiconductor switch S2 and diode D2, and therefore capacitor C is charged (period A). That is, in period A, the voltage Vc at both ends of capacitor C is high, and therefore the current IL (absolute value of the same) that flows into the induction heating unit 20 decreases.
[0085] When the charging of capacitor C is completed, the current IL flowing to the induction heating unit 20 becomes zero. When semiconductor switches S2 and S4 are turned on until capacitor C charging is completed, and then capacitor C charging is completed, the energy (charge) charged to capacitor C is supplied (discharged) through semiconductor switches S4 and S2. As a result, current IL flows through a path of the semiconductor switch S4 -> induction heating unit 20 semiconductor switch S2 (period B). That is, in this period B, the voltage Vc at both ends of capacitor C is decreased, and therefore the current IL (absolute value of the same) that flows into the induction heating unit 20 increases.
[0086] When the discharge of capacitor C is completed, the voltage Vc at both ends of capacitor C becomes zero, and therefore an inverse voltage is not applied to diodes D1 and D3. Therefore, diodes D1 and D3 enter a conduction state, and current IL flows through a path of semiconductor switch S4 induction heating unit 20 diode D1 and a path of diode D3 induction heating unit 20 switch of semiconductor S2 in parallel (period C). The current IL flows between the induction heating unit 20 and the MERS 130. Therefore, in period C, the absolute value of the current IL is attenuated in response to a time constant that is determined by the impedance of the heating coil on the upper side. 24, the bottom side heating coil 28, and the steel strip 10 which is an object to be heated.
[0087] Then, in dead time, not only the semiconductor switches S1 and S3, but also the semiconductor switches S2 and S4 are turned off. During the dead time, a current flows through a path of diode D1 capacitor C diode D3, and therefore the charging of capacitor C starts (period D). As a result, the voltage Vc at both ends of capacitor C is high, and therefore the current IL (absolute value of it) flowing into the induction heating unit 20 decreases. When the semiconductor switches S1 and S3 are turned on (at the same time as the semiconductor switches S2 and S4 are turned off) before the charging of capacitor C is completed, current flows through the path of the semiconductor switch S1 and diode D1 semiconductor switching capacitor C3 and diode D3, and therefore capacitor C is charged (period D). That is, in this period D, the voltage Vc at both ends of capacitor C is high, and therefore the current IL (absolute value of it) flowing into the induction heating unit 20 decreases.
[0088] When the charging of capacitor C is completed, the current IL flowing to the induction heating unit 20 becomes zero. When semiconductor switches S1 and S3 are turned on until capacitor C charging is completed, and then capacitor C charging is completed, the energy (charge) charged to capacitor C is supplied (discharged) through semiconductor switches S1 and S3. As a result, current IL flows through a path of the semiconductor switch S1 -> induction heating unit 20 semiconductor switch S3 (period E). That is, in this period E, the voltage Vc at both ends of capacitor C is decreased, and therefore the current IL (absolute value of the same) that flows into the induction heating unit 20 increases.
[0089] When the discharge of capacitor C is completed, the voltage Vc at both ends of capacitor C becomes zero, and therefore an inverse voltage is not applied to diodes D2 and D4. Therefore, diodes D2 and D4 enter a conduction state, and current IL flows through a path of the semiconductor switch S1 induction heating unit 20 -> diode D4 and a path of diode D2 induction heating unit 20 semiconductor switch S3 in parallel (period F). The current IL circulates between the induction heating unit 20 and the MERS 130. Therefore, in period F, the absolute value of the current IL is attenuated in response to a time constant that is determined by the impedance of the heating coil on the upper side 24, the bottom side heating coil 28, and the steel strip 10 which is an object to be heated. Then, it returns to the operation for period A, and operations for periods A to F are performed repeatedly.
[0090] As described above, when the on and off times (switching operation) of the respective port terminals G1 to G4 (G1 and G3, and G2 and G4) of semiconductor switches S1 to S4 (S1 and S3, and S2 and S4) are adjusted, a current of a desired frequency can be made to flow through the induction heating unit 20 (the heating coil on the top side 24 and the heating coil on the bottom side 28), thereby performing heating by induction of the type of frequency control. That is, due to the port control unit 140 which adjusts the conduction timing of semiconductor switches S1 to S4, a frequency of the current IL flowing into the induction heating unit 20 which is a load can be controlled to a value arbitrary. In addition, when the capacitance Cp of capacitor C is determined according to Equation (1) described below, the period in which the voltage Vc at both ends of capacitor C is zero can be adjusted. Cp = 1 / [(2xπxft) 2xL] - (1)
[0091] Here, Cp represents the capacitance (F) of capacitor C, and L represents the inductance (H) of the loads that include the induction heating unit 20. Additionally, ft represents an apparent frequency (Hz) with respect to the capacitor C, which is expressed by Equation (2) described below. ft = 1 / (2xt + 1 / f) - (2)
[0092] Here, t represents a period (sec) when the voltage Vc at both ends of capacitor C is zero, and f represents a frequency (Hz) of the voltage Vc and current IL in a case where a period in which the voltage Vc at both ends of capacitor C is zero is not present. When a capacitor C, which has the capacitance Cp that is obtained by replacing ft (ie, f) when t is zero in Equation (2) into Equation (1), a period in which the voltage Vc is selected at both ends of capacitor C zero is not present. Frequency Determination Unit Configuration 180
[0093] Returning to the description of figure 4, an example of a frequency determination unit 180 configuration will be described. The frequency determination unit 180 is a unit that determines the frequency (output frequency) of AC power to be provided for the induction heating unit 20. To perform its function, the frequency determination unit 180 includes a unit for obtaining information on the object to be heated 181, a frequency determination table 182, and a frequency selector. frequency 183.
[0094] The unit for obtaining information on the object to be heated 181 obtains attribute information from the steel strip 10 which is an object to be heated. For example, the information retrieval unit of the object to be heated 181 obtains (receives) attribute information from an external computer that is an input unit over a network, or obtains (enters) attribute information based on information that is entered through a user with respect to a user interface (one of the input units) provided to the control unit 100. Here, the attribute information of the steel strip 10 is information that is capable of specifying a permeability relative strength, strength, and blade thickness of steel strip 10. For example, the relative permeability, strength, and blade thickness of steel strip 10 can be determined as the attribute information, or in a case where the relative permeability, strength, and blade thickness of the steel strip 10 are determined according to specifications, a name (a trade name or the like) of the steel strip 10 that has the specifications can be determined as the attribute information.
[0095] A frequency selector 183 uses the attribute information obtained by the information obtaining unit of the object to be heated 181 as a key and selects a frequency among the frequencies recorded in the frequency determination table 182. In the frequency determination table frequency 182, attribute information and frequency are correlated with each other and are recorded in advance.
[0096] The information of a frequency (output frequency) if selected by frequency selector 183 is transmitted to the door control unit 140. The door control unit 140 determines on and off timings (switching operation) of the respective port terminals G1 to G4 of the semiconductor switches S1 to S4 of the MERS 130 so that the AC power of the selected frequency is generated, and provides a power signal for a port terminal of a semiconductor switch to be connected . In this way, the MERS 130 supplies the AC power of the frequency (the output frequency) which is determined for the door control unit 140 by the frequency determining unit 180 for the induction heating unit 20 as described above.
[0097] As described above, in this embodiment, the frequency (the output frequency) of the AC power to be supplied to the induction heating unit 20 is determined automatically in response to the relative permeability, strength, and blade thickness of the steel strip 10. This is based on a discovery through various experiments carried out by the inventors, specifically, a discovery in which the temperature distribution (particularly the temperature in the vicinity of an edge) of steel strip 10 is affected by the frequency of the AC power supplied to the induction heating unit 20, the attribute information (relative permeability, strength, and blade thickness) of the steel strip 10 that is an object to be heated, and a clearance (distance between the upper heating coil 24 and the lower heating coil 28).
[0098] Hereafter, the reason why this phenomenon occurs will be described.
[0099] First, a description will be made with respect to a case where the temperature of the steel strip 10 is equal to or greater than the Curie Temperature.
[00100] When the steel strip 10 is at a temperature that is equal to or greater than the Curie temperature, a main magnetic field that is generated from the induction heating unit 20 penetrates through the steel strip 10, and a current of Foucault within the steel strip 10 (within a plane orthogonal to the blade thickness) increases. This eddy current is repelled from a magnetic field and is able to be moved to the vicinity of the steel strip edge 10. Therefore, a high temperature region is suitable to occur in the vicinity of the steel strip edge 10.
[00101] Here, eddy current within the steel strip 10 is proportional to a cross-sectional area (cross-sectional area that includes a blade thickness direction) of the steel strip 10, so that in a case where the blade thickness of the steel strip 10 is large, the cross-sectional area of the steel strip 10 becomes large and therefore the eddy current within the steel strip 10 increases.
[00102] Additionally, eddy current of steel strip 10 is inversely proportional to a resistance of steel strip 10, so that in a case where the resistance of steel strip 10 is small, the eddy current within the strip steel 10 increases.
[00103] Additionally, a frequency of AC power supplied to the induction heating unit 20 is proportional to an induced electromotive force that is generated within the steel strip 10 due to the main magnetic field generated from the induction heating unit 20. A Eddy current of the steel strip 10 is proportional to the induced electromotive force, so that in a case where the frequency of the AC power supplied to the induction heating unit 20 is high, the eddy current within the steel strip 10 increases .
[00104] Additionally, in a case where the gap is small, the main magnetic field generated from the induction heating unit 20 becomes large, so that the induced electromotive force generated within the steel strip 10 due to the main magnetic field is it becomes large and therefore the eddy current within the steel strip 10 increases.
[00105] In the following, a description will be made with respect to a case where the temperature of steel strip 10 is lower than the temperature of Curie.
[00106] In a case where the temperature of the steel strip 10 is lower than the Curie temperature, a relative permeability of the steel strip 10 is large, so that the main magnetic field generated from the induction heating unit 20 is difficult to penetrate through the steel strip 10 and therefore deviates from the edge portion of the steel strip 10. As a result, in the vicinity of the edge of the steel strip 10 in the direction of the blade width, the current density of eddy current it becomes large, and therefore a high temperature region occurs in the vicinity of the edge of the steel strip 10 in the direction of the blade width.
[00107] As described above, the factors (the frequency of the AC power supplied to the induction heating unit 20, the relative permeability, strength, and blade thickness of the steel strip 10 which is an object to be heated, and the clearance), which have an effect on the temperature of the steel strip 10, are independent of each other. Among these factors, the permeability, strength, and blade thickness of the steel strip 10, and the clearance are determined by operating conditions (hardware restrictions on a material that is an object to be heated and an installation). Therefore, in this mode, among these factors, “the frequency (the output frequency) of the AC power supplied to the induction heating unit 20” that can be controlled in line is changed using the frequency determination unit 180 to adjust the steel strip temperature 10.
[00108] Additionally, as is the case with this modality, when all of the relative permeability, strength, and blade thickness of the steel strip 10, and the frequency are correlated with each other and are recorded in the frequency determination table 182 , the temperature distribution of the steel strip 10 in the direction of the blade width can be adjusted relatively evenly. Therefore, it is preferable that all of the relative permeability, strength, and blade thickness of the steel strip 10, and the frequency are correlated with each other. However, it is not necessary to correlate all of the relative permeability, strength, and blade thickness of the steel strip 10, and the frequency, and at least one of the relative permeability, strength, and blade thickness of the steel strip 10 can be correlated with the frequency in the frequency determining unit 180. In addition, at least one of relative permeability, strength, and blade thickness of the steel strip 10, and the gap can be correlated with the frequency. Output Current Determination Unit Configuration 150
[00109] The output current determination unit 150 is a unit that determines a magnitude (output current value) of the AC IL current supplied to the induction heating unit 20. By performing this function, the current determination unit output 150 includes a unit for obtaining information on the object to be heated 151, a table for determining the supplied current 152, and a supplied current selector 153.
[00110] The unit for obtaining information from the object to be heated 151 obtains attribute information from the steel strip 10 which is an object to be heated, similarly to the unit for obtaining information from the object to be heated 181.
[00111] The supplied current selector 153 uses the attribute information obtained by the information obtaining unit of the object to be heated 151 as a key and selects a current value among current values registered in the table for determining the supplied current 152. In the table for determining the current supplied 152, the attribute information and the current value are correlated with each other and are registered in advance. In addition, a control angle of the rectifier unit 110 is determined in response to a difference between the current value (the output current value) selected by the supplied current selector 153 and a current value measured by the current transformer 170. No in case of adopting a thyristor rectifying device such as rectifier unit 110, a thyristor gate firing angle is determined. In this way, the value of the current flowing into the induction heating unit 20 is fed back and the control angle (the gate trip angle) of the rectifier unit 110 is controlled, so that the value of the current flowing into the induction heating unit 20 can be constantly controlled to be the current value (output current value) selected by the supplied current selector 153. As a result, the power supply unit (the AC 160 power source and the unit rectifier 110) supplies DC power to the MERS 130, and therefore the alternating current measured by the current transformer 170 can be adjusted to the current value (the output current value) determined by the output current determination unit.
[00112] As described above, in this embodiment, the current value (the output current value) of the AC power supplied to the induction heating unit 20 is determined automatically in response to the relative permeability, strength, and blade thickness of the steel strip 10. This is because the current value corresponding to a target temperature can be determined by the relative permeability, strength, and blade thickness of the steel strip 10.
[00113] Additionally, in a similar way for this modality, when all relative permeability, strength, and blade thickness of the steel strip 10, and the current value are correlated with each other and are recorded in the table for current determination provided 152, a temperature distribution and an average temperature of the steel strip 10 in the direction of the blade width can be determined in a relatively appropriate manner. Therefore, it is preferable that all of the relative permeability, strength, and blade thickness of the steel strip 10, and the current value are correlated with each other. However, it is not necessary to correlate all of the relative permeability, strength, and blade thickness of the steel strip 10 with the current value, and at least one of the relative permeability, strength, and blade thickness of the steel strip 10 and the current value can be correlated with each other in the output current determination unit 150. Additionally, at least one of relative permeability, strength, and blade thickness of the steel strip 10, and the clearance can be correlated with the current value. Effect of this modality
[00114] Figure 6A shows a graph that illustrates the relationship between the frequency and temperature relationship with respect to the blade transport speed, when power is supplied to the induction heating unit 20 using control unit 100 according to the mode and a steel strip 10 is heated. Additionally, figure 6B shows a graph that illustrates the relationship between the frequency and temperature relationship with respect to a blade transport speed, when power is supplied to the induction heating unit 20 using a parallel resonance type inverter. a conventional technique and the steel strip 10 is heated. Here, a temperature ratio (edge / center temperature ratio) is a value obtained by dividing a temperature in an end part (edge) of the steel strip 10 in the direction of the blade width through a temperature in the central part of the steel strip 10 in the direction of the blade width thereof. The closer the temperature ratio approaches 1, the more uniform the temperature distribution of the steel strip 10 in the direction of the blade width. In addition, the frequency is a frequency of a current applied to the induction heating unit 20. Additionally, specifications of the steel strip 10 are as follows. Steel Strip Specifications - Material: Stainless steel blade - Blade thickness: 0.3 mm - Width: 500 mm
[00115] As shown in figure 6A, when control unit 100 is used according to this modality, even in a case where the transmission speed varies, the frequency of the current, which can be applied to the induction heating unit 20 , can be kept substantially constant, and therefore the temperature ratio can be controlled to be substantially constant.
[00116] On the other hand, when the transmission speed varies, the load impedance varies, so that in a case where the parallel resonance type inverter in the conventional technique is used, the voltage source inverter controls the frequency of inverter output such that a load resonance condition is maintained. Therefore, as shown in figure 6B, the output frequency of the inverter varies in response to a change in load impedance. As a result, the temperature ratio varies significantly and therefore the temperature ratio cannot be controlled to be constant.
[00117] As described above, according to this modality, the current IL of the frequency (the output frequency) corresponding to the attribute (attribute information) of the steel strip 10 is supplied to the induction heating unit 20 using the MERS 130. Therefore, the control unit according to this modality is not subject to a restriction with respect to an operation with a resonant frequency as the conventional technique, so that even when the transmission speed of the steel strip 10 varies, the frequency of the IL current that is supplied to the induction heating unit 20 can be determined to a desired value in response to the attribute of the steel strip 10. Therefore, when the conductive blade is heated using the induction heating unit of the type transverse, even when the transmission speed of the conductive blade varies, it is possible to prevent the temperature distribution of the conductive blade in the direction of the blade width from being uneven. In addition, the IL current of a frequency, which is suitable for the steel strip 10 which is an object to be heated (particularly, which makes the temperature distribution in the direction of the blade width as uniform as possible), can be determined for the induction heating unit 20.
[00118] Additionally, in this mode, the control angle of the rectifier unit 110 is changed in response to the attribute of the steel strip 10, and therefore the current IL which has a magnitude that corresponds to the attribute of the steel strip 10 is provided for the induction heating unit 20. As a result, the current IL which has an appropriate magnitude for the steel strip 10 which is an object to be heated can flow through the induction heating unit 20. Additionally, since the frequency is controlled to be constant, the temperature distribution of the conductive blade in the direction of the blade width can be uniformly controlled without actually having to measure the variation in temperature over time in various positions of the steel strip 10.
[00119] Furthermore, with respect to the induction heating system provided with the control unit 100 and the induction heating unit 20 which has the shield plates 31a to 31 d, since even when the transmission speed varies, the frequency of the AC power does not vary, it is not necessary to consider a variation (variation with the passage of time) in the eddy current generated at the edge part of the steel strip 10. Therefore, when the control unit 100 is used in the control system induction heating, even when operating conditions vary, an amount of heating in the vicinity of the edge can be appropriately controlled by the shield plates a to 31 d. Second Mode
[00120] In the following, a second embodiment of the present invention will be described. In the first embodiment described above, the alternating current IL is made to flow to the induction heating unit 20 directly through the MERS 130. In contrast, according to this modality, the alternating current IL is made to flow into the induction heating unit 20. by MERS 130 through a transformer. In this way, in a configuration of this modality, the transformer is added to the configuration described above of the first modality. Therefore, in this modality, the same reference symbols as those assigned in figure 1 to figure 6B will be assigned the same parts as in the first modality described above, and a detailed description of them will be omitted here.
[00121] Figure 7 shows a view illustrating an example of a configuration of a control unit 200 of an induction heating unit.
[00122] As shown in figure 7, the control unit 200 according to this mode additionally includes an output transformer 210 compared to the control unit 100 according to the first mode shown in figure 4.
[00123] A terminal on the primary side (input side) of output transformer 210 is connected to the AC terminals a and d of the MERS 130. A terminal on the secondary side (output side) of output transformer 210 is connected to the heating unit by induction 20 (copper bus bars 42a and 42g). The transformation rate (input: output) of output transformer 210 is N: 1 (N> 1).
[00124] As described above, in this modality, since the output transformer 210 which has the transformation rate of N: 1 (N> 1) is disposed between the MERS 130 and the induction heating unit 20, substantially N times the current of the current flowing through the MERS 130 can be made to flow to the induction heating unit 20. Therefore, in this embodiment, a large current can be made to flow to the induction heating unit 20 without making a large flow of current for the “semiconductor switches S1 to S4 and diodes D1 to D4” that make up the MERS 130.
[00125] Additionally, a plurality of connections can be provided on the primary or secondary side of output transformer 210 in such a way that the transformation rate of output transformer 210 can be changed, and the connection to be used can be used in response to the steel strip 10 which is an object to be heated. Third Mode
[00126] In the following, a third embodiment of the present invention will be described. In the first and second embodiments described above, a flat plate is used as the shield plates 31a to 31 d provided for the induction heating unit 20. In contrast, in this embodiment, a recessed part is formed in the shield plates provided for the induction heating unit 20. In this way, this mode and the first and second modes described above are different in part of a shielding plate configuration. Therefore, in this modality, the same reference symbols as those attributed in figure 1 to figure 7 will be attributed to the same parts in the first and second modalities described above, and a detailed description of them will be omitted here.
[00127] Figures 8A to 8C show views that illustrate an example of an induction heating unit configuration. Figure 8A, figure 8B, and figure 8C correspond to figure 2A, figure 2B, and figure 2C, respectively. Instead of the shield plates 31a to 31 d shown in figures 2A to 2C, shield plates 301a to 301 d are used. In addition, the shield plates 301a to 301 d are arranged in positions shown in figure 8B in such a way that the recessed portion described later is facing (opposite to) the steel strip 10 (in the second container 12). In addition, the induction heating unit includes an upper side inductor 201 and a lower side inductor 202. Additionally, the upper side inductor 201 and the lower side inductor 202 are substantially the same as the upper side inductor 21 and the lower side inductor 22 shown in figures 2A to 2C, respectively, except for the configuration of the shield plates.
[00128] Additionally, figures 9A to 9C show views that illustrate an example of a shield plate 301 configuration (shield plates 301a to 301 d). Specifically, figure 9A shows a perspective view taken looking over the top side of the shield plate 301. Additionally, figure 9B shows a view taken looking over a region of the shield plate 301 d shown in figure 8C just above the steel strip 10. Additionally, figure 9B shows only a part that is necessary to explain a positional relationship between steel strip 10 and shield plate 301 d. Additionally, figure 9C shows a schematic view illustrating an example of a magnetic field that is generated between the shield plates 301a, 301b and the steel strip 10. However, in figures 9B and 9C, the second container 12 is omitted for ease of understanding an effect of shield plates 301a to 301d.
[00129] As shown in figure 9A, the shield plate 301 includes a main shield plate 50a and a back plate 50b.
[00130] The width and length of the shield plate 50a are the same as those of the rear plate 50b. However, the rear plate 50b is formed of a copper plate in which a longitudinal section and a cross section are uniform, and in contrast, the main shield plate 50a is formed of a copper plate in which two rhombic holes are formed in the longitudinal direction of the same. The shield plate 301 is formed by close contact between the main shield plate 50a and the rear plate 50b, and has two rhombic recessed parts (non-penetrable holes) 51 and 52 in the longitudinal direction. Additionally, in figure 9A, the dimensions [mm] related to the positions in which the lowered parts 51 and 52 are arranged are also indicated.
[00131] As shown in figures 9B and 9C, the shield plate 301 is installed on the lower surface (slot side) of the core 23 and the upper surface (slot side) of the core 27 such that a surface on which the recessed parts 51 and 52 are formed facing the steel strip 10.
[00132] In this embodiment, as shown in figure 9B, the recessed parts 51 and 52 of the shield plate 301 (301 d) and a blade surface of the steel strip 10 are opposite each other in the vicinity of an edge 10a of the strip steel 10 in the direction of the blade width. Specifically, a region that is located on the edge side 10a compared to the maximum current passage region 56 is facing the recessed parts 51 and 52 of the shield plate 301. The region that is located on the edge side 10a includes a region between a maximum current passage region 56 which is a region in which eddy current flowing through the steel strip 10 becomes maximum through the operation of the induction heating unit and the edge 10a of the steel strip 10.
[00133] Particularly, in this modality, the edges of the inner side 51a and 52a of the lowered parts 51 and 52 of the shield plate 301 (301 d) are arranged on the side of the edge 10a compared to the maximum current passage region 56, and the edges of the outer side 51b and 52b of the recessed parts 51 and 52 are arranged on the edge side 10a compared to a current passing region of the edge 57 which is a region through which eddy current flows into the neighborhood of the edge 10a of the steel strip 10. Here, between the edges of the recessed parts 51 and 52, the edges of the inner side 51a and 52a are edges that are close to a central part in the direction of the width of the steel strip 10 and that are closest to the corresponding recessed parts 52 and 51 (or the central part of the shield plate 301 d in the direction of transport of the blade). Additionally, between the edges of the recessed parts 51 and 52, the edges of the inner side 51b and 52b are edges that are farthest from the central part of the steel strip 10 in the width direction and that are farthest away by the corresponding recessed parts 52 and 51 ( or the central part of the shield plate 301 d in the direction of transport of the blade).
[00134] In this embodiment, due to the shield plate 301 disposed as described above, a reduction in the temperature of the steel strip 10 in the vicinity of the edge 10a is suppressed. Hereinafter, a mechanism will be described, which suppresses a reduction in the temperature of the steel strip 10 in the vicinity of the edge 10a due to the shield plate 301.
[00135] As shown in figure 9C, when the induction heating unit is operated, the main magnetic fields 58a to 58c are generated, and therefore eddy currents 60a to 60e flow to one side of the edge of the steel strip 10 in the direction of the blade width. In addition, a magnetic field 59i is generated by eddy currents 60a to 60e. In addition, as shown in figures 9A to 9C, eddy currents 53 to 55 flow through the shield plate 301 (301a and 301b). Eddy current 53 is eddy current flowing along a rhombic edge portion of the shield plate 301 (main shield plate 50a). On the other hand, eddy currents 54 and 55 are currents that flow along an edge part of the lower parts 51 and 52 of the shield plate 301. Thus, on the shield plate 301, the edge chains 53 to 55 flow to the rhombic edge part of the shield plate 301 and the edge part of the recessed parts 51 and 52 of the shield plate 301 in a concentrated manner. In addition, magnetic fields 59a to 59h are generated by eddy currents 53 to 55.
[00136] As a result, as shown in figure 9C, a repulsive force is generated between eddy currents 54 and 55 that flow through the shield plate 301 (301a and 301b) and eddy current 60 that flows through the strip steel 10. Due to this repulsive force, eddy current 60 (60a to 60e) flowing through the edge portion of the steel strip 10 moves inward (in a direction of the arrow shown under the steel strip 10 in figure 9C) of the steel strip 10 and a current density in a region where a temperature decreases in the conventional technique increases. Therefore, a decrease in temperature in the vicinity of the edge (region slightly to the inner side of the edge) of the steel strip 10 can be suppressed, and therefore the shield plate 301 can adjust the degree of electromagnetic coupling between a region of the steel strip. steel 10 on the edge side in the direction of the blade width and the heating coils 24 and 28. Here, the shield plate 301 is made of copper, and a necessary property is maintained even at a high temperature. Therefore, even when the shield plate 301 is exposed to high temperatures, a decrease in the temperature of the steel strip 10 in the vicinity of the edge thereof can be suppressed.
[00137] On the contrary, in a case the lowered part is not present in the shield plate 31 as in the first modality, eddy current 53 and 54 does not flow through the shield plate 31 as shown in figures 9A and 9C, and an eddy current flows to the rhombic portion of the edge of the shield plate 31 in a concentrated manner. Therefore, an eddy current that flows into the vicinity of the edge of the steel strip 10 does not receive an inclined force towards the inner side (central side) of the steel strip 10, and a current density of one region (region slightly to the inner side of the edge of the steel strip 10) where a temperature decreases does not increase. Therefore, a decrease in temperature in the vicinity of the edge of the steel strip 10 may not be suppressed.
[00138] As described above, the inventors have found that when the lower parts 51 and 52 are formed on the shield plate 301 made of copper, and the shield plate 301 is arranged in such a way that the lower parts 51 and 52 are opposite to the in the vicinity of the edge of the steel strip 10, a decrease in temperature in the vicinity of the edge of the steel strip 10 can be suppressed. To confirm this finding, the inventors measured the temperature distribution in the direction of the blade width of a conductive blade (which corresponds to the steel strip 10) in a case where the shield plate 301 according to this modality is used and in a case where the shield plate 31 according to the first modality is used, respectively.
[00139] Figures 10A and 10B show views that illustrate an example of a temperature distribution of a conductive blade, which is heated by the induction heating unit, in the direction of the blade width.
[00140] Specifically, figure 10A shows a graph with respect to the induction heating unit (the induction heating unit according to this modality) using the shield plate 301 according to this modality. On the other hand, figure 10B shows a graph with respect to the induction heating unit (the induction heating unit according to the first embodiment) using the shield plate 31 according to the first embodiment. In addition, the horizontal axis of the graphs shown in figures 10A and 10B indicate a position in the direction of the width of the conductive blade, a position "0" on the horizontal axis corresponds to a leading edge of the blade, and a position "250" corresponds center of the conductive blade. On the other hand, the vertical axis represents an increase in temperature (increase in temperature) of the conductive blade due to heating. Here, the experimental conditions of the graphs shown in figures 10A and 10B are as follows.
[00141] Heating coil width: 250 [mm] (length in one direction of the blade transport) Core: Ferrite core Heating material: Non-magnetic SUS blade (stainless) (500 [mm] width, and a thickness of 0.3 [mm]) Blade transport speed: 8 [(m / minute)] Heating temperature: 30 to 130 [° C] (the temperature increase in a central part is determined to 100 [° C]) Power source frequency: 29 [kHz], 21 [kHz], and 10 [kHz] Shielding plate material: Copper
[00142] Additionally, the closer the relative permeability of a material approaches 1, the more easily the temperature in the vicinity of an edge decreases. In addition, when the temperature of the conductive blade (material to be heated) is equal to or greater than the Curie temperature, the relative permeability of the conductive blade becomes 1. Therefore, the non-magnetic (stainless) SUS blade was used as the heating material that has a relative permeability of 1.
[00143] As shown in figure 10A, in the induction heating unit using the shield plate 301 according to this modality, it can be understood that when the frequency is changed in the order of 29 [kHz] 21 [kHz] —► 10 [kHz], the edge temperature decreases, and a decrease in temperature in the vicinity of the edge (here, in a position from “50” to “100” on the horizontal axis) is suppressed (the temperature distribution in the direction of the blade width becomes uniform).
[00144] On the other hand, as shown in figure 10B, in the induction heating unit using the shield plate 31 according to the first modality, it can be understood that when the frequency is changed in the order of 29 [kHz] 21 [ kHz] 10 [kHz], the edge temperature decreases, but the temperature reduction in the vicinity of the edge (here, in a position from “50” to “100” on the horizontal axis) becomes large.
[00145] Additionally, in a case where the shield plate is not supplied, the temperature in the vicinity of the edge (here, in a position from "50" to "100" on the horizontal axis) does not decrease. However, since the temperature increases at the edge it becomes substantially 500 [° C], the edge has been overheated.
[00146] As described above, according to this modality, the lowered parts 51 and 52 are formed on the shield plate 301 made of copper, the shield plate 301 is arranged between the upper and lower side of the heating coils 24 and 28 and the steel strip 10 such that the recessed parts 51 and 52 are facing the edge of the steel strip 10. Therefore, even when the steel strip 10 is exposed to high temperatures, a decrease in the temperature of the strip steel 10 in the vicinity of its edge can be suppressed.
[00147] Furthermore, in the induction heating system provided with the control unit 100 and the induction heating unit that has the shield plate 301, even when the transmission speed varies, since the frequency of the AC power does not varies, it is not necessary to consider a variation (temporal variation) of eddy current that is generated at the edge part of the steel strip 10. Therefore, when the control unit 100 is used in the induction heating system, even when the conditions operating conditions vary, an increase in temperature in the vicinity of the edge can be appropriately controlled by the shield plate 301. Furthermore, since the lower parts 51 and 52 are formed on the shield plate 301, even when the relative permeability varies in response to a heated state of the steel blade, the temperature distribution in the vicinity of the edge can be controlled appropriately due to the recessed parts 51 and 52. Therefore, in the wake configuration o with this modality, it is possible to deal with a change in the heating speed in a relatively flexible way.
[00148] Additionally, in the modalities described above (from the first modality to the third modality), the shield plates 31 and 301 are not limited to a plate made of copper. That is, the shield plates 31 and 301 can be formed of any material as long as this material is a conductor that has a relative permeability of 1 (for example, metal that is a paramagnetic substance or a diamagnetic substance). For example, the shield plate 31 can be formed of aluminum.
[00149] Additionally, in this embodiment, the positional relationship between the steel strip 10 and the shield plate 301 is not particularly limited since the lowered parts of the shield plate 301 and the steel strip 10 (which also includes an extended plane steel strip 10) are opposite each other in a region that is present on the edge side 10a compared to the maximum current passage region 56. However, it is preferable that a region between the maximum current passage region 56 and the edge 10a of steel strip 10, and at least part of the recessed parts of the shield plate are opposite each other as shown in figure 9B so that a repulsive force generated safely between the eddy current flowing through the plate shield 301 and eddy current flowing through steel strip 10.
[00150] Additionally, in this modality, a description has been made with respect to a case in which the two recessed parts are formed on the shield plate as an example, but the number of recessed parts formed on the shield plate is not limited.
[00151] Additionally, in this modality, an illustration was made with respect to a case in which the shape of the lowered parts 51 and 52 is a rhombic shape as an example. However, the shape of the lowered parts 51 and 52 can be any shape as long as eddy current can be made to flow through the steel strip 10 along the edge part of the lowered parts 51 and 52. The shape of the lowered parts 51 and 52 can be, for example, an ellipse, a rectangle different from the rhombic shape, or other square shapes. At this point, when a recessed part is formed where the length in the transport direction of the blade is longer than in a direction orthogonal to the transport direction of the blade, eddy current can easily be made to flow along a part of edge of the recessed part. Therefore, it is preferable to form a recessed part where the length in the direction of transport of the blade is longer than in the direction orthogonal to the direction of transport of the blade. In addition, it is not necessary for the shape of the recessed part on the shield plate to be closed. For example, the recessed portion may be formed at an end portion of the shield plate.
[00152] In addition, copper is normally used for the top side heating coil 24 and the bottom side heating coil 28, but a conductor (metal) other than copper can be used. In addition, an induction heating system other than the continuous annealing line can be adopted. In addition, the dimensions of cores 23 and 27 shown in figure 2A can be determined appropriately within a range where cores 23 and 27 are not magnetically saturated. Here, the generation of magnetic saturation in cores 23 and 27 can be determined from the strength of the magnetic field [A / m] which is calculated by the current flowing through the heating coils 24 and 28.
[00153] Additionally, in the embodiments described above, both the upper side inductor 21 and the lower side inductor 22 are provided as an example, but either the upper side inductor 21 or the lower side inductor 22 can be provided. In addition, the gap size is not particularly limited.
[00154] Additionally, all of the modalities of the present invention described above illustrate only a specific example for carrying out the present invention, and a technical scope of the present invention is not limited to the modalities. That is, the present invention can be carried out in various ways without departing from its technical scope or critical characteristics. INDUSTRIAL APPLICABILITY
[00155] It is possible to provide a control unit for an induction heating unit, an induction heating system, and a method of controlling the induction heating unit, in which a temperature distribution in the direction of the width of the blade a conductive blade is made more uniformly compared to conventional techniques, even when the transmission speed of the conductive blade varies in a case where the conductive blade is heated using a transversal type induction heating unit. LIST OF REFERENCE SYMBOLS 10: Steel strip (Conductive blade) 20: Induction heating unit 23: 27: Core (Magnetic core) 24: Top side heating coil (Heating coil) 28: Side heating coil bottom (Heating coil) 31a to 31d: Shielded plate 51.52: Lowered part (Valley part) 100, 200: Induction heating unit control unit 110: Rectifier unit 120: Reactor 130: Heat recovery switch magnetic energy (MERS) 131: to 134: First to fourth semiconductor switches of the reverse conductivity type 140: Port control unit 150: Output current determination unit 160: AC power source 170: Current transformer (Unit current measurement) 180: Frequency determination unit 210: Output transformer 301: Shielded plate S1 to S4: Semiconductor switches D1 to D4: Diodes

权利要求:
Claims (13)
[0001]
1. Induction heating system that allows an alternating magnetic field to cross a blade surface of a conductive blade (10) being charged to inductively heat the conductive blade (10) comprising: an induction heating unit (20) including a heating coil (24, 28) which is arranged facing the blade surface of the conductive blade (10); a control unit (100, 200) that controls an AC power output to a heating coil (24, 28), where the control unit (100, 200) includes: a magnetic energy recovery switch (130) that supplies AC power to the heating coil (24, 28); a frequency determination unit (180) which determines an output frequency in response to at least one of relative permeability, resistivity, and blade thickness of the conductive blade (10); and a door control unit (140) that controls a switching operation of the magnetic energy recovery switch (130) based on the output frequency determined by the frequency determining unit (180), and on which the heating unit induction (20) includes: a core (23, 27) around which the heating coil (24, 28) is wound; and characterized by the fact that said induction heating unit (20) includes a shield plate (31a, 31b, 31c, 31 d, 301a, 301b, 301c, 301 d) which is arranged facing a region that includes a edge (10a) of the conductive blade (10) in a width direction, and has a recessed portion (51, 52) on the blade that faces the conductive blade (10), and is formed from a conductor that has a relative permeability of 1, and in which the shield plate is arranged in such a way that a region, which is closer to the edge (10a) of the conductive blade (10) than a region in which an eddy current flowing into the conductive blade (10) reaches a maximum, and the recessed part (51, 52) is turned towards each other.
[0002]
2. Induction heating system according to claim 1, characterized by the fact that: an edge on the inner side (51a, 52a) of the edges of the recessed part (51, 52), which is on one side closer to a central portion in the direction of the width of the conductive blade (10) is arranged in such a way that the edge of the conductive blade (10) is closer to the edge of the inner side (51a, 52a) than a region through which the current Foucault flow flows to the conductive blade (10) reaches a maximum, and an edge on the outer side (51b, 52b) of the edges of the recessed part (51, 52), which is on one side farthest from the central portion in the direction of the width of the conductive blade (10), is arranged in such a way that the edge of the conductive blade (10) is closer to the outer edge (51b, 52b) than a region through which eddy current flows to the edge of the conductive blade (10).
[0003]
3. Induction heating system according to claim 1, characterized by the fact that the frequency determining unit (180) obtains attribute information that specifies the relative permeability, resistivity, and blade thickness of the blade conductive (10), and selects a frequency that corresponds to the attribute information obtained as the output frequency with reference to a table in which the relative permeability, resistivity, and the thickness of the conductive blade (10), and the frequency they are correlated with each other and are registered in advance.
[0004]
Induction heating system according to any one of claims 1 to 3, characterized by the fact that the control unit further comprises: an output current determination unit (150) that determines a current value of output in response to at least one of the relative permeability, resistivity, and blade thickness of the conductive blade (10); a current measurement unit (170) that measures an alternating current flowing through the induction heating unit (20); and a power supply unit (110, 160) which supplies DC power to the magnetic energy recovery switch (130) and adjusts the alternating current that is measured by the current measurement unit (170) to the current value output which is determined by the output current determination unit (150), in which the magnetic energy recovery switch (130) is supplied with DC power by the power supply unit (110, 160) and supplies the power AC to the heating coil (24, 28).
[0005]
5. Induction heating system according to claim 4, characterized by the fact that the output current determination unit (150) obtains attribute information that specifies the relative permeability, resistivity, and blade thickness of the conductive blade (10), and selects a current value that corresponds to the attribute information obtained as the output current value with reference to a table in which the relative permeability, resistivity, and blade thickness of the conductive blade ( 10), and the current value are correlated to each other and are registered in advance.
[0006]
Induction heating system according to any one of claims 1 to 5, characterized by the fact that it further comprises: an output transformer (210) which is arranged between the magnetic energy recovery switch (130) and the induction heating unit (20), reduces an AC voltage that is provided by the magnetic energy recovery switch (130), and supplies the reduced AC voltage to the heating coil (24, 28).
[0007]
Induction heating system according to any one of claims 1 to 6, characterized in that the magnetic energy recovery switch (130) includes: first and second AC terminals (d, a) that are connected to one end and another end of the heating coil (24, 28), respectively, first and second DC terminals (b, c) which are connected to an output terminal of a power supply unit (110, 160), a first semiconductor switch of the reverse conductivity type (131) that is connected between the first AC terminal (d) and the first DC terminal (b), a second semiconductor switch of the reverse conductivity type (132) that is connected between the first AC terminal (d) and the second DC terminal (c), a third semiconductor switch of the reverse conductivity type (133) which is connected between the second AC terminal (a) and the second DC terminal (c), a fourth conductivity type semiconductor switch reverse (134) that is connected between the second AC terminal (a) and the first DC terminal (b), and a capacitor (C) that is connected between the first and second DC terminals (b, c); the first semiconductor switch of the reverse conductivity type (131) and the fourth semiconductor switch of the reverse conductivity type (134) are connected in series in such a way that the driving directions at the time of a shutdown become opposite to each other ; the second semiconductor switch of the reverse conductivity type (132) and the third semiconductor switch of the reverse conductivity type (133) are connected in series in such a way that driving directions at the time of shutdown become opposite to each other; the first semiconductor switch of the reverse conductivity type (131) and the third semiconductor switch of the reverse conductivity type (133) have both the same driving direction at the time of shutdown; the second semiconductor switch of the reverse conductivity type (132) and the fourth semiconductor switch of the reverse conductivity type (134) have both the same driving direction at the time of shutdown; and the door control unit (140) controls a time of the switching operation of the first and third semiconductor switches of the reverse conductivity (131, 133) and a time of the switching operation of the second and fourth semiconductor switches of the type of reverse conductivity (132, 134) based on the output frequency which is determined by the frequency determining unit (180).
[0008]
8. Method for controlling the induction heating system, as defined in any of claims 1 to 7, characterized in that it comprises: supplying AC power to the heating coil (24, 28) through a recovery switch magnetic energy (130); determining an output frequency in response to at least one of the relative permeability, resistivity, and blade thickness of the conductive blade (10); and controlling a switching operation of the magnetic energy recovery switch (130) based on the output frequency that is determined.
[0009]
9. Method for controlling the induction heating system, according to claim 10, characterized in that the output frequency is determined by obtaining an attribute information that specifies the relative permeability, resistivity, and blade thickness of the conductive blade (10), and selecting a frequency that corresponds to the attribute information obtained as the output frequency with reference to a table in which the relative permeability, resistivity, and blade thickness of the conductive blade (10), and the frequency are correlated with each other and are recorded in advance.
[0010]
10. Method for controlling the induction heating system according to claim 8 or 9, characterized by the fact that it further comprises: determining an output current value in response to at least one of the relative permeability, resistivity, and the blade thickness of the conductive blade (10); measuring an alternating current flowing to the induction heating unit (20); and providing DC power, which is necessary to adjust the alternating current that is measured to the output current value that is determined, for the magnetic energy recovery switch (130).
[0011]
11. Method for controlling the induction heating system according to claim 10, characterized by the fact that the output current value is determined by obtaining an attribute information that specifies the relative permeability, resistivity, and thickness of conductive blade blade (10), and selecting a current value that corresponds to the attribute information obtained as the output current value with reference to a table in which the relative permeability, resistivity, and blade thickness of the conductive blade (10), and the current value are correlated with each other and are registered in advance.
[0012]
12. Method for controlling the induction heating system according to any of claims 8 to 11, characterized in that an AC voltage that is supplied by the magnetic energy recovery switch (130) is reduced via a transformer output (210), and reduced AC voltage is supplied to the heating coil (24, 28).
[0013]
13. Method for controlling the induction heating system according to any one of claims 8 to 12, characterized in that the magnetic energy recovery switch (130) includes: first and second AC terminals (d, a) which are connected to one end and the other end of the heating coil (24, 28), respectively, first and second DC terminals (b, c) which are connected to an output terminal of the power supply unit (110, 160 ), a first semiconductor switch of the reverse conductivity type (131) that is connected between the first AC terminal (d) and the first DC terminal (b), a second semiconductor switch of the reverse conductivity type (132) which is connected between the first AC terminal (d) and the second DC terminal (c), a third semiconductor switch of the reverse conductivity type (133) which is connected between the second AC terminal (a) and the second DC terminal (c) , a fourth type semiconductor switch of reverse conductivity (134) which is connected between the second AC terminal (a) and the first DC terminal (b), and a capacitor (C) which is connected between the first and second DC terminals (b, c), the first semiconductor switch of the reverse conductivity type (131) and the fourth semiconductor switch of the reverse conductivity type (134) are connected in series in such a way that the driving directions at the time of a shutdown become opposite to each other , the second semiconductor switch of the reverse conductivity type (132) and the third semiconductor switch of the reverse conductivity type (133) are connected in series in such a way that the driving directions at the time of shutdown become opposite to each other , the first semiconductor switch of the reverse conductivity type (131) and the third semiconductor switch of the reverse conductivity type (133) have both the same driving direction at the time of shutdown, the second semic switch reverse conductivity type (132) and the fourth reverse conductivity type semiconductor switch (134) both have the same driving direction at shutdown, and AC power is supplied to the heating coil (24 , 28) by controlling a time of the switching operation of the first and third semiconductor switches of the reverse conductivity type (131, 133) and a time of the switching operation of the second and fourth semiconductor switch of the reverse conductivity type (131, 133) 132, 134) based on the output frequency that is determined.

类似技术:

---

公开号 | 公开日 | 专利标题

---

BR112012016028B1|2020-10-27|induction heating system that allows an alternating magnetic field to cross a blade surface and method for controlling it

---

US10327287B2|2019-06-18|Transverse flux induction heating device

---

JP6400663B2|2018-10-03|Contactless power transformer

---

BRPI0807653A2|2011-11-08|induction heating apparatus

---

Zhu et al.2018|Achieving low magnetic flux density and low electric field intensity for a loosely coupled inductive wireless power transfer system

---

Xu et al.2013|Electromagnetic field and thermal distribution optimisation in shell-type traction transformers

---

JP6665928B2|2020-03-13|Induction heating device and induction heating method

---

JP6331900B2|2018-05-30|Induction heating device for metal strip

---

Khemakhem et al.2014|An improved LLC resonant inverter for induction heating applications

---

Bhaumik et al.2017|Analysis of leakage inductance for multi-zone induction heater

---

TWI598001B|2017-09-01|Induction heating device and induction heating method

---

Umetani et al.2018|Improved thin heating coil structure of copper foil feasible for induction cookers

---

JP5131232B2|2013-01-30|Transverse induction heating device

---

KR20130029521A|2013-03-25|Power supply and system for that

---

KR200208038Y1|2000-12-15|INDUCTION HEATING & iron system

---

Swart et al.1993|Integrated water cooled transformer and work coil for middle frequency induction heating applications

同族专利:

---

公开号 | 公开日

---

EP2515609A1|2012-10-24|

---

JPWO2011074383A1|2013-04-25|

---

KR101464419B1|2014-11-21|

---

JP4917182B2|2012-04-18|

---

US20160100458A1|2016-04-07|

---

CA2783411A1|2011-06-23|

---

CA2783411C|2016-04-26|

---

KR20120083530A|2012-07-25|

---

US20160100459A1|2016-04-07|

---

IN2012DN05033A|2015-10-02|

---

US9907120B2|2018-02-27|

---

PL2515609T3|2018-07-31|

---

JP2011216502A|2011-10-27|

---

MX2012006731A|2012-06-28|

---

WO2011074383A1|2011-06-23|

---

HK1171900A1|2013-04-05|

---

CN102652459B|2014-09-24|

---

EP2515609A4|2014-12-03|

---

CN102652459A|2012-08-29|

---

BR112012016028A2|2016-08-16|

---

US9247590B2|2016-01-26|

---

RU2510163C2|2014-03-20|

---

US20120305547A1|2012-12-06|

---

RU2012125958A|2014-01-27|

---

EP2515609B1|2018-02-07|

---

US9942949B2|2018-04-10|

引用文献:

---

公开号 | 申请日 | 公开日 | 申请人 | 专利标题

---

---

US2448008A|1943-12-07|1948-08-31|Westinghouse Electric Corp|Controlled induction heating|

---

US2448012A|1944-09-09|1948-08-31|Westinghouse Electric Corp|Induced heating of continuously moving metal strip with pulsating magnetic flux|

---

US3444346A|1966-12-19|1969-05-13|Texas Instruments Inc|Inductive heating of strip material|

---

JPS6214796B2|1977-02-17|1987-04-03|Seikoo Epuson Kk|

---

US4357512A|1980-07-23|1982-11-02|Sumitomo Kinzoku Kogyo Kabushiki Kaisha|Apparatus for continuous manufacture of butt-welded pipe|

---

FR2583249B1|1985-06-07|1989-04-28|Siderurgie Fse Inst Rech|DEVICE FOR INDUCTIVELY HEATING THE RIVES OF A METALLURGICAL PRODUCT AND VARIABLE GAP INDUCTOR|

---

JPS6327836B2|1985-08-09|1988-06-06|Sumitomo Heavy Industries|

---

JPH0335790B2|1985-10-25|1991-05-29|Nippon Light Metal Co|

---

US4824536A|1988-06-15|1989-04-25|Allegheny Ludlum Corporation|Method for processing cold-rolled stainless-steel sheet and strip|

---

GB8902090D0|1989-01-31|1989-03-22|Metal Box Plc|Electro-magnetic induction heating apparatus|

---

JPH0349561A|1989-07-14|1991-03-04|Mitsubishi Heavy Ind Ltd|Controller for power source in induction heating for alloying|

---

US5157233A|1990-01-17|1992-10-20|Sumitomo Heavy Industries, Ltd.|Electromagnetic induction heater for heating a continuous thin sheet without undulation|

---

US5034586A|1990-05-03|1991-07-23|Ajax Magnethermic Corporation|Induction heating assembly including an interposed closed conductive loop for suppression of intercoil coupling|

---

US5360963A|1991-05-31|1994-11-01|Contour Hardening, Inc.|Apparatus for and method of induction-hardening machine components|

---

RU2032996C1|1991-07-03|1995-04-10|Самарский государственный технический университет|Device for control over temperature of flat billet during induction heating|

---

GB2262420B|1991-12-03|1995-02-08|Electricity Ass Tech|Induction heating apparatus|

---

FR2693071B1|1992-06-24|2000-03-31|Celes|DEVICE FOR HOMOGENEOUS INDUCTIVE HEATING OF FLAT METAL PRODUCTS IN A RUNWAY.|

---

US5378879A|1993-04-20|1995-01-03|Raychem Corporation|Induction heating of loaded materials|

---

US5467139A|1993-09-30|1995-11-14|Thomson Consumer Electronics, Inc.|Muting apparatus for a compressed audio/video signal receiver|

---

EP1008398B1|1993-12-16|2003-03-19|Kawasaki Steel Corporation|Method for joining metal pieces|

---

US5739506A|1996-08-20|1998-04-14|Ajax Magnethermic Corporation|Coil position adjustment system in induction heating assembly for metal strip|

---

US5770838A|1996-09-11|1998-06-23|Drever Company|Induction heaters to improve transitions in continuous heating system, and method|

---

JP3493448B2|1996-09-17|2004-02-03|ミノルタ株式会社|Induction heating fixing device|

---

US5827056A|1997-01-09|1998-10-27|Drever Company|Device and method for improving strip tracking in a continuous heating furnace|

---

US6026273A|1997-01-28|2000-02-15|Kabushiki Kaisha Toshiba|Induction heat fixing device|

---

JP2001006862A|1999-06-23|2001-01-12|Sumitomo Heavy Ind Ltd|Electromagnetic induction heating device|

---

JP2001006863A|1999-06-23|2001-01-12|Sumitomo Heavy Ind Ltd|Electromagnetic induction heating device|

---

JP3270028B2|1999-09-10|2002-04-02|株式会社ソニー・コンピュータエンタテインメント|Electromagnetic shield plate, electromagnetic shield structure, and entertainment device|

---

DE60032627T2|1999-11-03|2007-10-04|Nexicor, LLC, Cincinnati|INDUCTION HANDSET|

---

DE10011050A1|2000-03-07|2002-01-03|Vacuumschmelze Gmbh|Transformer for a compensation current sensor|

---

FR2808163B1|2000-04-19|2002-11-08|Celes|TRANSVERSE FLOW INDUCTION HEATING DEVICE WITH MAGNETIC CIRCUIT OF VARIABLE WIDTH|

---

US6576878B2|2001-01-03|2003-06-10|Inductotherm Corp.|Transverse flux induction heating apparatus|

---

US6570141B2|2001-03-26|2003-05-27|Nicholas V. Ross|Transverse flux induction heating of conductive strip|

---

JP2002313547A|2001-04-09|2002-10-25|Mitsui Eng & Shipbuild Co Ltd|Induction heating device for plate|

---

US6727483B2|2001-08-27|2004-04-27|Illinois Tool Works Inc.|Method and apparatus for delivery of induction heating to a workpiece|

---

JP5332072B2|2001-09-04|2013-11-06|Ｊｆｅスチール株式会社|Heat treatment method and apparatus for thick steel plate|

---

US6576877B2|2001-09-14|2003-06-10|The Boeing Company|Induction processing with the aid of a conductive shield|

---

US6930293B2|2002-02-04|2005-08-16|Canon Kabushiki Kaisha|Induction heating apparatus, heat fixing apparatus and image forming apparatus|

---

ES2555116T3|2002-08-07|2015-12-29|Panasonic Corporation|Induction heating device|

---

JP4024119B2|2002-09-26|2007-12-19|独立行政法人科学技術振興機構|Electromagnetic welding equipment using semiconductor switch and welding transformer|

---

JP4110046B2|2003-06-10|2008-07-02|キヤノン株式会社|Image heating device|

---

CN1810069B|2003-06-26|2010-06-23|应达公司|Electromagnetic shield for an induction heating coil|

---

JP2005049815A|2003-07-14|2005-02-24|Konica Minolta Business Technologies Inc|Induction-heating fixing device and image forming apparatus|

---

US20050061803A1|2003-09-18|2005-03-24|General Electric Company|Apparatus for induction heating and method of making|

---

JP4295141B2|2004-03-12|2009-07-15|株式会社吉野工作所|Work heating apparatus and work heating method|

---

DE102005005892A1|2005-02-09|2006-08-10|Haimer Gmbh|Induction coil unit|

---

TWI276689B|2005-02-18|2007-03-21|Nippon Steel Corp|Induction heating device for a metal plate|

---

JP4597715B2|2005-03-01|2010-12-15|多田電機株式会社|Magnetic heating device|

---

EP1994798A4|2006-02-22|2011-11-23|Inductotherm Corp|Transverse flux electric inductors|

---

US7386243B2|2006-03-07|2008-06-10|Kabushiki Kaisha Toshiba|Heating apparatus and induction heating control method|

---

EP2008499A2|2006-03-29|2008-12-31|Inductotherm Corp.|Transverse flux induction heating apparatus and compensators|

---

JP4406733B2|2006-10-05|2010-02-03|国立大学法人東京工業大学|Inverter power supply|

---

JP4964737B2|2006-11-27|2012-07-04|新日本製鐵株式会社|Induction heating method and apparatus for metal material|

---

JP4494397B2|2006-12-26|2010-06-30|三菱電機株式会社|Induction heating device|

---

US20090057301A1|2007-08-28|2009-03-05|Jean Lovens|Electric induction heating apparatus with fluid medium flow through|

---

JP2009093805A|2007-10-03|2009-04-30|Toshiba Corp|Heating cooking system and heating cooking device|

---

JP4505491B2|2007-11-05|2010-07-21|新日本製鐵株式会社|Apparatus and method for heating welded portion of steel pipe|

---

WO2009139079A1|2008-05-15|2009-11-19|国立大学法人 東京工業大学|Power supply for induction heating|

---

JP5068695B2|2008-05-27|2012-11-07|新日本製鐵株式会社|Induction heating method and induction heating apparatus|

---

CA2783411C|2009-12-14|2016-04-26|Nippon Steel Corporation|Control unit of induction heating unit, induction heating system, and method of controlling induction heating unit|US7641992B2|2004-10-29|2010-01-05|Medtronic, Inc.|Medical device having lithium-ion battery|

---

KR20120079069A|2009-08-14|2012-07-11|온스 이노베이션스, 인코포레이티드|Reduction of harmonic distortion for led loads|

---

CA2783411C|2009-12-14|2016-04-26|Nippon Steel Corporation|Control unit of induction heating unit, induction heating system, and method of controlling induction heating unit|

---

EP2538749B1|2010-02-19|2018-04-04|Nippon Steel & Sumitomo Metal Corporation|Transverse flux induction heating device|

---

JP5751453B2|2012-10-04|2015-07-22|株式会社デンソー|Induction heating device|

---

CN104717771B|2013-12-17|2016-08-17|北京交通大学|Steel cord belt induction heating apparatus|

---

JP6306931B2|2014-04-23|2018-04-04|トクデン株式会社|Induction heating roller device|

---

ES2783283T3|2014-12-12|2020-09-17|Nippon Steel Corp|Power supply device, joining system and conduction processing method|

---

JP6391175B2|2015-10-06|2018-09-19|東芝三菱電機産業システム株式会社|Induction heating device|

---

GB201518809D0|2015-10-23|2015-12-09|The Technology Partnership Plc|Temperature sensor|

---

US10193324B2|2015-11-13|2019-01-29|Silicon Power Corporation|Low-loss and fast acting solid-state breaker|

---

US10193322B2|2015-11-13|2019-01-29|Silicon Power Corporation|Low-loss and fast acting solid-state breaker|

---

KR101994572B1|2016-05-24|2019-06-28|닛폰세이테츠 가부시키가이샤|Power System|

---

CN105821185B|2016-05-30|2017-10-20|吉林大学|High strength steel gradient induction heating apparatus|

---

TWI705634B|2019-08-16|2020-09-21|益力半導體股份有限公司|Signal attached single firewire power control system and method|

---

WO2021263107A1|2020-06-26|2021-12-30|Ajax Tocco Magnethermic Corporation|Transverse flux induction heating device for heating flat product|

法律状态:
2017-08-01| B25D| Requested change of name of applicant approved|Owner name: NIPPON STEEL AND SUMITOMO METAL CORPORATION (JP) |

---

2019-01-08| B06F| Objections, documents and/or translations needed after an examination request according [chapter 6.6 patent gazette]|

---

2019-04-30| B06T| Formal requirements before examination [chapter 6.20 patent gazette]|

---

2019-08-20| B25D| Requested change of name of applicant approved|Owner name: NIPPON STEEL CORPORATION (JP) |

---

2020-02-18| B06A| Patent application procedure suspended [chapter 6.1 patent gazette]|

---

2020-04-07| B09A| Decision: intention to grant [chapter 9.1 patent gazette]|

---

2020-10-27| B16A| Patent or certificate of addition of invention granted [chapter 16.1 patent gazette]|Free format text: PRAZO DE VALIDADE: 20 (VINTE) ANOS CONTADOS A PARTIR DE 22/11/2010, OBSERVADAS AS CONDICOES LEGAIS. |

优先权:

---

申请号 | 申请日 | 专利标题

---

JP2009283255|2009-12-14|

---

JP2009-283255|2009-12-14|

---

PCT/JP2010/070800|WO2011074383A1|2009-12-14|2010-11-22|Control device for induction heating device and method for controlling induction heating system and induction heating device|

---