• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    A method for determining the polarity of a rotary electric machine rotor (1) pole having an estimated position relative to a stator, the method comprising the steps of: a) energizing the stator so as to successively generate within a saturable magnetic zone of said pole two different magnetic fluxes, one in conjunction and the other in opposition with the magnetic flux of the magnets, so as to saturate the saturable magnetic zone for at least one of the magnetic fluxes, and b) determining the polarity of the pole as a function of the differences in the time course of the current generated in the stator by the two flows.
    公开号:FR3016256A1
    申请号:FR1450101
    申请日:2014-01-07
    公开日:2015-07-10
    发明作者:Xavier Jannot；Jacques Saint-Michel；Mathias Tientcheu-Yamdeu
    申请人:Moteurs Leroy Somer SA；
    IPC主号:
    专利说明:

    [0001] The present invention relates to rotating electrical machines and in particular those comprising a rotor with permanent magnets. The object of the invention is to determine the position of at least one pole of the permanent magnet rotor at a standstill and without the use of conventional position sensors. The invention more particularly relates to a method for determining the position of at least one pole of a permanent magnet rotor and a device for determining the position of the poles. The invention is generally applicable to synchronous motors comprising a rotor with permanent magnets, and preferably permanent-magnet synchronous motors or machines having a flux-concentration rotor. The control of a synchronous motor with permanent magnets is based on the knowledge of the position of the rotor and in particular the position and the polarity of the north and south poles of the rotor. It is necessary to know the position and polarity of the poles both at startup, when the rotor is stopped, and in operation, when the rotor is rotating. For this purpose, it is well known to use position sensors, such as, for example, Hall effect sensors, encoders, resolvers or any other type of physical sensor. However, the use of such sensors causes a certain size, an additional cost and a risk of failure due to the use of an additional component. It is also known, when the rotor is in motion, either to use a voltage sensor integrated in a drive of the machine, or to circulate in the motor a current by applying a zero voltage output of the drive, for example, which current can be detected and analyzed by the drive. The direction of this current is directly related to the direction of the rotor. Such devices are for example known from US 6 163 127, US2004 / 0070362 and US2007 / 0040528. When the rotor is stopped, various methods make it possible to obtain information on the position of the rotor, but the information on the polarity of the poles is missing, uncertain or expensive to obtain. It is possible to align the rotor of the motor in a known position by the drive by injecting a DC current of known direction and until the rotor, which must then be free, comes to align in this direction. Alternatively, in the case where the starting load torque is low, we can also use observers capable of converging without a priori to the correct position of the machine. Other methods exploit the saliency of the rotor. High frequency signals can be injected to determine the position of the rotor at approximately 180 ° electric, that is to say that the position of the rotor poles is known but without knowing their north or south polarity, as described. in US application 2010/0171455. To know the polarity of the poles, one can analyze the high order harmonics of the injected frequency, in particular the harmonic of rank 2, as described in the application US 2009/0128074. However, it is then necessary to use very accurate current sensors and therefore expensive to measure these quantities, which are by their rank harmonic of very low value. Another method is to inject a voltage slot and analyze the current response to determine polarity of the poles. In this method, the stator saturation phenomenon is used, based on flux variations measured with respect to the flux of the vacuum magnets which polarizes the magnetic circuit of the stator. The method described above has a more reliable result that the flow of the vacuum magnets is important, so as to obtain a sufficiently large difference between the flow variations. However, this is the case only when the flux produced by the rotor on the magnetic circuit of the stator is sufficiently large, that is to say for example in the case of a rotor with a high flux concentration or in the case of magnets with high energy density, for example thanks to the use of rare earths for the magnets of the rotor. On the other hand, this method does not provide good results when it is applied to a synchronous-reluctance motor comprising permanent magnets in the rotor, and more particularly when these permanent magnets are at low energy density, being for example magnets made ferrite. Indeed, in the case of synchronous motors and rotor use of permanent magnets low energy density, the vacuum flow may be too low for the result to be sufficiently reliable and can be a rate of high error. In addition, to overcome this problem, one can try to obtain a larger current variation, but this can induce a high risk of demagnetization of low energy density magnets.
    [0002] Also, there is a need to benefit from a method of determining the position and pole polarity of a more reliable and less expensive rotating electrical machine rotor, even in the case where the vacuum magnet flux is relatively high. low. The object of the invention is to respond to this need and thus, according to a first aspect, to a method for determining the polarity of a rotary electric machine rotor pole having an estimated position with respect to a stator, the method comprising the following steps: a) energizing the stator so as to generate successively within a saturable magnetic zone of said pole two different magnetic fluxes, one in conjunction and the other in opposition to the magnetic flux of the magnets, saturating the saturable magnetic zone for at least one of the magnetic fluxes; and b) determining the polarity of the pole as a function of the differences in the time course of the current generated in the stator by the two magnetic fluxes. The method according to the invention is preferably implemented at standstill, that is to say before the rotation of the machine. In the invention, not used the saturation of the stator but the saturation of the rotor to determine the polarity of the poles of the rotor. The method according to the invention makes it possible to know the polarity of the poles of the rotor without risk of demagnetization of the magnets, a risk which is all the more important when the magnets are at low energy density, and with satisfactory reliability. In addition, the use of conventional position sensors can be avoided, thereby reducing the cost of the machine and eliminating the risk of malfunction and maintenance of the position sensor. The method according to the invention reduces the risk of unwanted rotation of the rotor. The presence of the saturable magnetic zones of the rotor can also serve to improve the assembly of the various components of the rotor, in particular the permanent magnets and the rotor magnetic mass, and contribute to the mechanical robustness of the rotor. By "saturable magnetic zone" of the rotor is meant areas of the magnetic circuit of the rotor that can be saturated very quickly, that is to say well before saturation of the rest of the magnetic circuit of the rotor.
    [0003] The presence of the saturable magnetic zones makes it possible to add to the flux of the magnets or to subtract from the flux of the magnets the flux created in the magnetic circuit of the rotor by the current flowing in the windings of the stator. Indeed, the resulting current rises faster when the flux created is in phase opposition with the flux of the magnets.
    [0004] This is explained by the fact that the leakage flux of the magnets through the saturable magnetic zones polarizes these areas of the magnetic circuit of the rotor, and this has the effect of reducing the inductance of the machine. Each pole of the rotor comprises at least one saturable magnetic zone. The rotor preferably comprises permanent magnets with low energy density. Permanent magnets can for example be made of ferrite. The magnets can, alternatively, be high energy density, but with a low vacuum flow. By "low vacuum flow" is meant that the electromotive force for an applied voltage of 100 V is less than 65V, better less than 50V. The excitation of the voltage stator may consist in applying to the stator a first and a second voltage which may be in the form of a voltage slot, having for example a shape chosen from the following list: voltage slot, voltage ramp, wave sinusoidal voltage or any combination of these forms, this list is not limiting. The first and second voltages can be of opposite sign. The second voltage is preferably of the same magnitude as the first voltage. The resulting currents can be between 0% of the maximum current before demagnetization and 100% of the maximum current leading to a beginning of demagnetization of the magnets, or even less than this maximum current, better than 50% of the maximum current, for example being understood between 2.5% and 50% of the maximum current, better between 5% and 40% of the maximum current. Sufficient variations are obtained to enable the polarity of the pole to be distinguished by the presence of the saturable magnetic zones. With a rotor devoid of saturable magnetic zones, a current greater than the value of the maximum current would be required in order to be able to distinguish a difference in the current variations and to determine the polarity of the poles. There would be significant risks of demagnetization of the magnets.
    [0005] It is determined in step b) which of the currents generated in the stator by the two magnetic fluxes is the weakest and / or the most retarded relative to the other. The current generated weakest or most late relative to the other indicates which of the two voltages has been applied in conjunction with the magnet or magnets of the corresponding pole, that is to say that we obtain the desired indication of the polarity of the studied pole. If the applied positive voltage generates a flux in conjunction with the flow of permanent magnets, it is the North Pole. The current with the smallest amplitude corresponds to the application of a voltage generating a flux in conjunction with the north pole. In other words, the north pole of the rotor corresponds to the case where the current level is the lowest at the end of the same duration and for the same amplitude of the applied voltage. Complementarily, the south pole of the rotor corresponds to the case where the current level is the highest at the end of the same duration and for the same amplitude of the applied voltage. It should be noted that this goes against the standard criteria for permanent magnet machines with high energy density. This stems from the fact that the phenomenon of saturation of the saturable magnetic zones of the rotor is exploited in the invention. The current rises faster when the created flow is in phase opposition with the flux of the magnets. This is explained by the fact that the leakage flux of the magnets through the saturable magnetic zones polarizes these areas of the magnetic circuit of the rotor; which has the effect of reducing the inductance of the machine. Alternatively or additionally, it is possible to determine in step b) the sign of the phase of one of the harmonics, in particular the second harmonic, having excited the stator in step a) with a high frequency signal. The case where the sign of the phase is positive corresponds to the application of a high frequency signal generating a flow in conjunction with the north pole, which is the opposite of the generally established criterion. The estimated position of the rotor pole relative to the stator can be determined by applying high frequency signals in the stator and then analyzing the resulting high frequency voltages and currents to derive the position of a pole of the rotor. This position of a pole of the rotor has an inaccuracy as to the polarity of the pole.
    [0006] Injection of high frequency signals does not require mechanical blocking of the rotor. The method for determining the polarity of a pole can be done without having to mechanically force the shaft of the machine to avoid rotation. Bridges The rotor may have permanent magnets arranged in housings so as to define poles of the rotor. The housings can be arranged in the form of an arc or a V. A saturable magnetic zone can be (i) a bridge of magnetic material arranged between rotor housings for receiving the permanent magnets, which are arranged in such a way as to define the poles of the rotor, and / or (ii) a bridge of magnetic material disposed between a housing and the air gap of the machine. The saturable magnetic zones can be arranged on either side of the magnets. The bridges formed between the housings can be oriented radially, that is to say arranged along a radial axis of the corresponding pole. By "radial axis of the pole" means an axis of the pole oriented radially, that is to say, according to a radius of the rotor. It can be an axis of symmetry for the pole. This radial axis can intersect the summit of the pole. As a variant, they may be oriented obliquely, that is to say that the material bridge extends generally along a longitudinal axis of the bridge oriented obliquely towards the radial axis of the corresponding pole of the rotor, when one moves away from the axis of rotation. The obliquely oriented material bridges make it possible to withstand the centrifugal forces to which the rotor can be subjected, without penalizing the machine on the magnetic plane. By "longitudinal axis of the bridge" means the axis disposed centrally relative to the two short sides of the adjacent housing defining the bridge material. This axis is preferably rectilinear. The bridges of material formed between the housings may extend obliquely generally along a longitudinal axis of the bridge which can form with the radial axis of the corresponding pole of the rotor an angle of a non-zero value and greater than 5 °, better than 10 °, for example of the order of about 15 °. The angle may be less than 45 °, more preferably less than 30 °, or even less than 20 °. The circumferentially oriented material bridges make it possible to maintain the cohesion of the rotor against the mechanical stresses experienced by the machine.
    [0007] The material bridges may have a width, measured perpendicularly to their longitudinal axis, less than 8 mm, better less than 7 mm. In order to optimize the distribution of the magnetic flux in the rotor, it is sought to limit the size of the bridges in order to minimize the passage of the magnetic flux in these bridges and the losses of flux in the pole. On the other hand, it is necessary that these bridges have a sufficient thickness to prevent them from breaking, the rotor being very strongly stressed by the centrifugal forces. The bridges of material may have a width greater than 0.5 mm, or even greater than 6 mm. Device The invention further relates, in another of its aspects, independently or in combination with the foregoing, to a device for determining the polarity of a rotary electric machine rotor pole having an estimated position with respect to a stator , the device comprising: a) means for exciting the stator in voltage so as to generate successively within a saturable magnetic zone of said pole two different magnetic fluxes, one in conjunction and the other in opposition to the magnetic flux of the magnets, so as to saturate the saturable magnetic zone for at least one of the magnetic fluxes, and b) means for determining the polarity of the pole as a function of the differences in the evolution of the current generated in the stator by the two magnetic flux. In another aspect, the invention also relates to a frequency converter for an electric motor, comprising a device for determining the polarity as described above. The invention further relates, in another of its aspects, to a rotating electrical machine comprising: - a motor comprising a rotor with permanent magnets, and - a variator as described above, for controlling the motor. The machine may comprise a stator wound on teeth. Alternatively, the stator may be distributed winding. The machine can constitute a synchronous motor.
    [0008] The machine is preferably devoid of a conventional position sensor. In other words, it is possible to obtain, thanks to the machine, according to the invention, the polarity of the pole studied without having to use a conventional position sensor. The machine can operate at a nominal peripheral speed (tangential velocity taken at the outer diameter of the rotor) which may be greater than or equal to 100 meters per second, the machine according to the invention allowing operation at high speeds if desired. The machine can have a relatively large size. The diameter of the rotor may be greater than 50 mm, more preferably greater than 80 mm, being for example between 80 and 500 mm. Rotor The rotor comprises a rotor magnetic mass in which are provided housing for receiving the permanent magnets, so as to define the poles of the rotor. The rotor may comprise at least one magnet per pole, for example a single magnet per pole, or alternatively two magnets, or more magnets per pole. The rotor may be flux-concentration or permanent-magnet synchronous-reluctant. Each pole of the rotor may comprise at least one saturable magnetic zone. The rotor may comprise at least three housings per pole, each pole having a radial axis of the pole, permanent magnets being inserted into housings. Permanent magnets can be inserted in all or part of the dwellings, for example in at least half of the dwellings, or even in more than two thirds of the dwellings, better still in all the dwellings. The housing can be elongated and each have two small sides. The housing can be arranged in one or more rows per pole, a row having at least two, preferably at least three housings arranged consecutively, their short sides defining between two consecutive housing of the same row a material bridge. The layout of the rows of housings makes it possible to concentrate the flow of the magnets and to introduce magnetic saliency in order to obtain interesting performances with ferrite magnets.
    [0009] In an exemplary embodiment, the housings of the same row are arranged in a central branch and two lateral branches located on either side of the central branch, giving for example a U-shaped configuration, the central branch being for example alone to include one or more permanent magnets, the side branches not housing permanent magnet. For the same pole, the housing of this pole can be arranged in a single row. The concavity of the row can be oriented towards the top of the pole, that is towards the gap. Preferably, for the same pole, the housing of this pole are arranged in several rows, each concavity which can be oriented towards the top of the pole, in particular in substantially concentric rows. By "concentric" is meant that the middle axes of the rows of housing, taken in a plane perpendicular to the axis of rotation of the rotor, intersect at one point. This arrangement in several concentric rows makes it possible to improve the concentration of the flux and the magnetic saliency without necessarily having to increase the size of the housings or the quantity of permanent magnets necessary to obtain equivalent performances. The number of rows per pole can in particular be two, three or four. When the rotor has several rows for the same pole, the latter may be of decreasing length when moving towards the air gap, the longest being closer to the axis of rotation and the shorter one being closer to the axis of rotation. the air gap. The length of a row is the cumulative length of the dwellings in that row. At least two housings of two rows of the same pole can extend parallel to each other. All one-row dwellings may extend parallel to the corresponding dwellings of another row. A row may comprise a number of dwellings strictly greater than one, for example at least two dwellings, better three dwellings. A row may for example comprise a central housing and two lateral housing. At least one row may comprise an odd number of dwellings, for example at least three dwellings. Two rows of the same pole may have a different number of dwellings. In an exemplary embodiment of the invention, at least one pole comprises a row of housings having a lower number of housings than those of another row of this pole, for example two against three for the other row. The row with the smallest number of housings is preferably the closest to the gap and furthest from the axis of rotation. The arrangement of the housings and / or material bridges in a row is preferably symmetrical with respect to the radial axis of the pole. In a row, the housing can be arranged in V or U, the U may have a flared shape towards the air gap. In other words, the housing constituting the lateral branches of the U may be non-parallel to each other. Thus, the inclination of the radial bridges can be opposite to that of the lateral housings, with respect to the radial axis of the pole. The housings may each extend, when observed in section in a plane perpendicular to the axis of rotation of the rotor, along a longitudinal axis which may be rectilinear or curved. The housings can have a constant or variable width when moving along their longitudinal axis, in a plane perpendicular to the axis of rotation of the rotor. The short sides of a housing are oriented towards the radial axis of the pole when moving away from the axis of rotation, and converge for example substantially to the top of the pole. The housing may have, in cross section, that is to say perpendicular to the axis of rotation, a generally rectangular or trapezoidal shape, this list is not limiting. The short sides of a dwelling may be perpendicular to the long sides of the dwelling. The short sides of a housing can be inclined relative to the long sides of the housing. At least one dwelling may have two long sides, one of the long sides being smaller than the other. In this case, for example when the housing is generally trapezoidal in shape, the shortest of the long sides may be located closer to the gap than the longest of the long sides. The short sides of a housing can be rectilinear or curved. Permanent magnets may be of a generally rectangular shape. Given the shape of the housing, the establishment of magnets in the housing can leave a free space in the housing between the magnets and the short sides of the corresponding housing. The free space is for example of generally triangular shape. The rotor mass may be formed of a stack of sheets or one or more individual sheet (s) wound (s) on it (s) itself (s) around the axis of rotation. Each sheet metal layer of the rotor mass can be in one piece. The rotor may be devoid of individual pole pieces. The rotor may comprise a number of poles between 2 and 12, better still between 4 and 8. The invention will be better understood on reading the following detailed description of non-limiting exemplary embodiments thereof, and examining the appended drawing, in which: - Figure 1 is a schematic and partial view of a rotating electrical machine according to the invention - Figures 2, 2a and 2b are views similar to Figure 1 of variant embodiments, FIG. 3 illustrates the evolution of the current in the stator of FIG. 1 during the application of a voltage slot, FIG. 4 is a view similar to FIG. 1 of a machine devoid of saturable magnetic zones - FIG. 5 illustrates the evolution of the current in the stator of FIG. 4 during the application of a voltage slot; FIGS. 6a and 6b illustrate the evolution of the field lines in the machine of the FIG. 1 - FIG. 7 illustrates a voltage ramp; FIG. 8 illustrates the evolution of the current in the stator of FIG. 1 during the application of a voltage ramp; FIGS. 9a, 9b, 9c, 11a, 11b and 11c respectively illustrate the measurements of the speed, the position and the voltage and the intensity in the machine of FIG. 1 during two implementations of the method of the invention, and FIGS. 10a and 10b and 12a and 12b are detailed views respectively of the figures 9b and 9c and 1 lb and 11c.
    [0010] FIG. 1 illustrates a rotary electric machine 1, comprising a stator 2 and a rotor 3 having a flux concentration, having a rotor magnetic mass 4 in which housings 5 are formed so as to define the poles of the rotor, each pole having a radial axis X. In this example, the rotor has nine housings 5 per pole, which are arranged in three concentric rows 6 around each of the poles, the concavity of the rows being oriented towards the gap. A row 6 has three housings 5 arranged consecutively in the row. The three rows 6 of the same pole are of decreasing length when moving towards the gap, the longest being located on the side of the axis of rotation and the shortest side of the air gap. The housing 5 are elongated. They each comprise two small sides 9, the respective narrow sides 9 of two consecutive housings 5 of the same row 6 defining between them a material bridge 10. The material bridge 10 extends generally along a longitudinal axis Z of the oriented bridge approaching the radial axis X of the corresponding pole of the rotor 1 as one moves away from the axis of rotation. The longitudinal axis Z of the material bridge 10 is rectilinear and forms with the radial axis X of the corresponding pole of the rotor an angle α of a non-zero value and greater than 5 °, which in this example is of the order of about 15 °. The small sides 9 of a housing are oriented in the direction of the radial axis X of the pole as one moves towards the air gap. The housings 5 are generally trapezoidal, and have two long sides, one of the long sides being smaller than the other, the shortest of the long sides being closer to the gap than the longest of the long sides. The lateral housings are separated from the air gap by circumferential material bridges 12. These bridges of circumferential material 12 take up only a small part of the centrifugal forces, whereas the bridges 10 which separate two housings must support the essential of the load of centrifugal forces. The rotor 1 may comprise permanent magnets 11 inserted in each or in some of the housings 5. The permanent magnets are low energy density. The permanent magnets 11 are in this example of generally rectangular shape in cross section. The placement of the magnets in the housing can leave a free space in each housing between the magnet and the short sides of the corresponding housing.
    [0011] As seen in Figure 1, some of the housing may be devoid of magnet. In the exemplary embodiment illustrated, the housings of one of the rows are arranged in a central branch and two lateral branches, the central branch being only to include a permanent magnet, the lateral housing does not comprise a permanent magnet. In addition, we see in Figure 1 that the central housing of a row may have a length greater than that of the lateral housing of said row, and the lateral branches of the U are shorter than the central branch. This is the opposite in the variant embodiment illustrated in FIG. 2. Furthermore, in this FIG. 2, the bridges formed between the housings are oriented radially, that is to say arranged along a radial axis of the corresponding pole. As a further variant, the row D of housings closest to the gap may comprise a central bridge 10, as shown in FIG. 2a. In another variant, the housing can be arranged in V rather than U, as shown in Figure 2b. Material bridges 10 and circumferential bridges 12 which have just been described form saturable magnetic zones of the rotor. The machine 1 illustrated in Figure 1 further comprises a drive 20 for controlling the motor, which comprises a device 25 for determining the stopping of the polarity of the poles of the rotor, the machine being devoid of conventional position sensor. The device 25 for determining the polarity comprises: a) means for exciting in voltage the stator 2 so as to generate successively within a saturable magnetic zone 10, 12 of said pole two different magnetic fluxes, one in conjunction with the other in opposition to the magnetic flux of the magnets 11, so as to saturate the saturable magnetic zone 10, 12 for at least one of the magnetic fluxes, and b) means for determining the polarity of the pole as a function of the differences in evolution in time of the current generated in the stator by the two magnetic fluxes. We will now describe in detail the operation of this device and the progress of the method of determining the polarity according to the invention.
    [0012] Determination of the position of the poles In the absence of current in the stator windings, the permanent magnets polarize the magnetic circuit. Firstly, an estimated position of a pole of the rotor is determined, for example by applying high frequency signals in the stator and then analyzing the resulting voltages and high frequency current to deduce the position of the pole of the rotor. This determination can be done alternatively by any other means. In this step, we make an assumption about the polarity of the pole, which for the moment unknown to 180 ° electrical close, and which will be verified or invalidated in the following steps. Voltage excitation When a stator is applied to the stator in the form of a voltage slot for a time t defined so as to create a magnetic flux in a saturable magnetic zone 10, 12 of said pole of the rotor, it is possible to measure a resulting current in the stator. FIG. 3 shows the evolution of the current in the stator windings of FIG. 1 when the flux created by a voltage slot is applied in conjunction (curve D +) or in phase opposition (curve D-) with the flux of the magnets . The shape of the current curve D + in the case where the flux created by the voltage slot is in conjunction with the flux of the magnets is due to the reversal of the flow direction in the saturable magnetic zones 10, 12 of the rotor, as can be seen in FIGS. 6a and 6b, which show the evolution of the flow distribution in the motor of FIG. 1 in the case where the flow created is in conjunction with that of the magnets. It is worth noting the evolution of the field lines in the various saturable magnetic zones 10, 12 of the rotor. Figure 6a illustrates the flow at t = Os and Figure 6b at t = 0.0035s. The presence of the saturable magnetic zones 10, 12 slows the rise of the current and makes it possible to discriminate the directions of the north and south poles, as will be explained hereinafter. By contrast, FIG. 5 shows the evolution of the current in the stator windings when the flux created by the voltage slot is applied in conjunction (curve D +) or in phase opposition (curve D-) with the flux of the magnets, in the case where the rotor does not have saturable magnetic zones, as is the case of the machine of Figure 4, which comprises a rotor with magnets low energy density but devoid of saturable magnetic zones. Without these saturable magnetic zones, it takes a current greater than the maximum current before demagnetization Imax to start to detect the direction of the poles. There is a strong risk of demagnetizing the magnets if you use such a high current. On the other hand, with low current levels, lower than the maximum current, for example between 2.5% and 50% of the maximum current I m, and saturable magnetic zones, the distinction between the current evolution in the two cases is more net. This eliminates the risk of demagnetizing the magnets. It can thus be seen that without saturable magnetic zones, the application of a voltage in both directions does not make it possible to discriminate the direction of the poles accurately and robustly. 9 will now be described with reference to FIGS. 9a to 9c and 10a and 10b, an exemplary implementation of the method according to the invention, with the machine of FIG. 2, which is a synchronous-reluctant motor with permanent ferrite magnets. The measurements are carried out with the controller 20. The starting is carried out with a speed reference Vref of 100 rps / min, as illustrated in FIG. 9a which shows the evolution over time of the reference speed Vref, of the estimated speed Ve and the actual speed Vr. Phase A is the determination of the initial position, followed by the actual start phase B. Phase A comprises a phase A1 for determining the estimated position Pe and a phase A2 for determining the polarity. Figures 10a and 10b are detail views of phase A2. An estimated position Pe is first determined as described above (phase A1). In fact, this estimated position Pe has in fact an ambiguity of 180 ° electric which will be raised thanks to the phase A2. Figures 9b and 10a show the evolution over time of the actual position Pr, the estimated position Pe and the error E between the two. To do this, a first voltage is applied to the stator in the form of a small voltage slot for a time t defined so as to create a magnetic flux in a saturable magnetic zone 10, 12 of said pole of the rotor, and a measurement is made of first current resulting in the stator.
    [0013] A second voltage is then applied in the form of a second phase pulse phase-shifted spatially 180 ° electrical with respect to the first voltage slot during the time t defined so as to create a magnetic flux in the saturable magnetic zone 10, 12 of said rotor pole, and a second current resulting in the stator is measured. The evolution of the voltage U + and the resultant intensity I + are illustrated in FIGS. 9c and 10b. Thus, in one case, a flow is created in the same direction as that of the magnets - in conjunction - and in the other case, a flow in opposition of phase with respect to the flux of the magnets. In the foregoing, a voltage slot has been used. Of course, it is not beyond the scope of the present invention if it is otherwise, and one can for example use another form for the excitation voltage. By way of example, FIGS. 7 and 8 illustrate the use of a voltage ramp. A voltage ramp U + was applied as illustrated in FIG. 7 for a time t defined so as to create a flow oriented in the same direction as that of the magnets, then the same voltage ramp U- but phase shifted spatially from 180 was applied. ° electric. In doing so, in one case the flux created by the voltage ramp will be in the same direction as that of the magnets - in conjunction - and in the other case, it will be in phase opposition with respect to the flux of the magnets. FIG. 8 shows the evolution of the current in the windings of the motor when the flux created by the voltage ramp U + is applied in conjunction (curve D +) or in opposition of phase (curve D-) with the flux of the magnets and in the case where the rotor has saturable magnetic circuits. It can be seen after a time t defined that the current reaches two different values, which makes it possible to discriminate the directions of the north and south poles. In another variant, the excitation of the stator by sinusoidal voltages can make it possible to determine the polarity of the poles of the rotor. In this case, the sign of the phase of the component of the generated current is detected at twice the excitation frequency (harmonic of rank 2). The north pole corresponds to a positive phase shift, which is the opposite of the criterion generally considered in conventional solutions implementing sinusoidal voltages for the detection of polarity.
    [0014] Determination of polarity The pole polarity of the rotor can be deduced as a function of the first and second measured currents that are generated in the stator by the two magnetic fluxes. To do this, it is determined in step b) which of the first and second currents is the weakest and / or the most late compared to the other. The north pole of the rotor corresponds to the case where the current level is the lowest at the end of the same duration and for the same amplitude of the applied voltage. In the test of FIGS. 9a to 9c, the magnitude of the current resulting from the first voltage range is smaller than the second, as shown in detail in FIG. 10b. The first variation of current is about 26A, the second of -40A. The maximum current of the motor is 230 A. There is therefore both a sufficiently marked difference of 11.3% and - 17.5% to make a reliable decision while staying at low current levels compared to the maximum current . Contrary to the conventional situation, it is concluded here that the estimated position Pe is the right one, as confirmed by the measurement Pr indicated by a position sensor (resolver) used here for verification purposes only, illustrated in FIGS. 9b and 10a. The drive then starts with this position (phase B), and we see in Figure 9b a good superposition between the angle given by the position sensor and the angle obtained without mechanical sensor by the method according to the invention. In the embodiment variant illustrated in FIGS. 11a to 11c and 12a and 12b, everything is identical to the preceding test except that at the end of phase A1, the estimated position Pe is 180 ° electrical from that Pr indicated by the resolver, as shown in the curve of Fig. 1 lb. At the end of phase A2, the current corresponding to the first voltage range is the largest, the first current variation being 30A, the second of 16A, respectively + 13% and -7%. The difference is sufficiently marked between the two senses for the clearing of the ambiguity on polarity to be very clear with current levels still far below the nominal current. It is deduced (here also, contrary to the classical approach) that the correct position is at 180 ° electric and this value is added to the estimated position Pe after which the position Pe is superimposed on the actual position Pr observed by the resolver, and the error E drops to 0.
    [0015] In addition to avoiding the risk of demagnetization, one of the advantages of the method of the invention is its low risk of rotating the rotor during the test, a risk that is always present with very high current levels. of the classical solution when the measurement of the estimated position has a deviation from the actual position. The invention is not limited to the illustrated examples. In particular, it is possible to modify the polarity of the rotor without departing from the scope of the present invention. The rotor can cooperate with any type of stator, distributed or concentrated winding. The phrase "with one" should be understood as being synonymous with "having at least one".
    权利要求:
    Claims (16)
    [0001]
    REVENDICATIONS1. A method for determining the polarity of a rotor rotating machine pole (3) having an estimated position relative to a stator, the method comprising the steps of: a) energizing the stator to generate successively within a saturable magnetic zone of said pole two different magnetic fluxes, one in conjunction and the other in opposition with the magnetic flux of magnets of the rotor defining the pole of the rotor, so as to saturate the saturable magnetic zone to at least one of the 10 magnetic fluxes, and b) determine the polarity of the pole as a function of the differences in the evolution over time of the current generated in the stator by the two flows.
    [0002]
    2. Method according to the preceding claim, wherein the rotor (3) comprises permanent magnets (11) at low energy density, in particular ferrites. 15
    [0003]
    3. Method according to any one of the preceding claims, which is implemented at standstill, that is to say before the rotation of the machine (1).
    [0004]
    4. A method as claimed in any one of the preceding claims, wherein energizing the stator in voltage comprises applying to the stator a first and a second voltage which have a shape selected from the following list: voltage slot, voltage ramp , sinusoidal voltage wave.
    [0005]
    5. Method according to any one of the preceding claims, wherein the resulting currents are lower than the maximum current before demagnetization (Lu), better than 50% of the maximum current, in particular between 2.5% and 50% of the current. maximum. 25
    [0006]
    6. Method according to any one of the preceding claims, wherein it is determined in step b) which of the currents generated in the stator by the two magnetic fluxes is the weakest and / or the most retarded relative to the other.
    [0007]
    7. A method according to any one of the preceding claims, wherein the north pole of the rotor corresponds to the case where the current level is the lowest at the end of the same duration and for the same amplitude of the applied voltage.
    [0008]
    8. The method of claim 4, wherein the second voltage is of the same magnitude as the first voltage.
    [0009]
    9. A method according to any one of the preceding claims, wherein the estimated position of the pole of the rotor relative to the stator is determined by applying high frequency signals in the stator and then analyzing the voltages and high frequency current resulting to deduce the position of a pole of the rotor.
    [0010]
    The method according to any one of the preceding claims, wherein a saturable magnetic zone (10, 12) is (i) a bridge of magnetic material (10) provided between housings (9) of the rotor (3) for receiving the permanent magnets (11), which are arranged to define the poles of the rotor, and / or is (ii) a bridge of magnetic material (12) disposed between a housing (9) and the air gap of the machine.
    [0011]
    11. Apparatus (25) for determining the polarity of a rotary electric machine rotor pole (3) (1) having an estimated position relative to a stator (2), the device comprising: a) Means for exciting in voltage the stator so as to generate successively within a saturable magnetic zone of said pole two different magnetic fluxes one in conjunction and the other in opposition with the magnetic flux of rotor magnets defining the pole of the rotor, so saturating the saturable magnetic zone for at least one of the magnetic fluxes, and b) means for determining the polarity of the pole as a function of the differences in the time course of the current generated in the stator by the two magnetic fluxes.
    [0012]
    12. Frequency converter (20) for an electric motor, comprising a device (25) for determining the polarity according to the preceding claim.
    [0013]
    13. A rotary electric machine (1) comprising: - a motor comprising a rotor (3) with permanent magnets (11), and 25 - a variator (20) according to the preceding claim, for controlling the motor.
    [0014]
    14. Machine according to the preceding claim, wherein the rotor (3) is flux concentration or permanent magnet synchronizing-reluctant.
    [0015]
    15. Machine according to one of the two preceding claims, wherein each pole of the rotor (3) comprises at least one saturable magnetic zone (10,12). 30
    [0016]
    16. Machine according to one of claims 13 to 15 comprising a stator (2) wound on teeth or distributed winding.
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    同族专利:
    公开号 | 公开日
    EP3092711A2|2016-11-16|
    EP3092711B1|2020-03-25|
    US20160329845A1|2016-11-10|
    CN105900317B|2020-11-27|
    FR3016256B1|2016-01-22|
    CN105900317A|2016-08-24|
    WO2015104609A2|2015-07-16|
    WO2015104609A3|2016-01-21|
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    法律状态:
    2015-12-29| PLFP| Fee payment|Year of fee payment: 3 |
    2017-01-31| PLFP| Fee payment|Year of fee payment: 4 |
    2017-12-29| PLFP| Fee payment|Year of fee payment: 5 |
    2020-01-28| PLFP| Fee payment|Year of fee payment: 7 |
    2021-01-28| PLFP| Fee payment|Year of fee payment: 8 |
    2021-11-29| PLFP| Fee payment|Year of fee payment: 9 |
    优先权:
    申请号 | 申请日 | 专利标题
    FR1450101A|FR3016256B1|2014-01-07|2014-01-07|METHOD FOR DETERMINING THE POLARITY OF A ROTOR POLE OF A ROTATING ELECTRIC MACHINE|FR1450101A| FR3016256B1|2014-01-07|2014-01-07|METHOD FOR DETERMINING THE POLARITY OF A ROTOR POLE OF A ROTATING ELECTRIC MACHINE|
    CN201480072586.0A| CN105900317B|2014-01-07|2014-12-19|Method and apparatus for determining polarity of rotor magnetic pole, frequency converter and electric rotating machine|
    US15/110,305| US20160329845A1|2014-01-07|2014-12-19|Method for determining the polarity of a rotor pole of an electrical rotating machine|
    PCT/IB2014/067109| WO2015104609A2|2014-01-07|2014-12-19|Method for determining the polarity of a rotor pole of an electrical rotating machine|
    EP14833242.2A| EP3092711B1|2014-01-07|2014-12-19|Method for determining the polarity of a rotor pole of an electrical rotating machine|
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