• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
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  • 优先权
    • 专利摘要:
    Axial flow switched reluctance machine and an electric vehicle comprising the machine. The present invention relates to an axial flow switched reluctance machine, comprising: - a stator (S) comprising stator poles (p1) distributed along a first circumferential path in the same stator plane; - electromagnet coils (L) wound at least in some of the stator poles (p1); and - a rotor (R) comprising rotor poles (p2) distributed along a second circumferential path in a rotor plane orthogonal to an axis of rotation, parallel to said stator plane and separated from it by a space at long axis of rotation. At least the stator poles (p1) or the rotor poles (p2) are distributed non-equidistantly along the first and second circumferential paths, respectively. The invention also concerns an electric vehicle, comprising an electric motor that includes the AFSRM of the invention.
    公开号:ES2666212A1
    申请号:ES201631377
    申请日:2016-10-26
    公开日:2018-05-03
    发明作者:Pere ANDRADA GASCÓN；Eusebi MARTÍNEZ PIERA；Marcel TORRENT BURGUÉS；Balduí；Blanqué Molina；José Ignacio PERAT BENAVIDES；José Antonio SÁNCHEZ LÓPEZ
    申请人:Universitat Politecnica de Catalunya UPC；
    IPC主号:
    专利说明:

    DESCRIPTION

    Axial flow switched reluctance machine and an electric vehicle comprising the machine.
     5
    Field of the invention.

    The present invention, in general, refers in a first aspect to an axial flow switched reluctance machine (AFSRM), and more particularly to an AFSRM with a specific pole distribution of stator or rotor, which provides an improvement in machine performance.
    image 1
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    image3

    A second aspect of the invention relates to an electric vehicle comprising an electric motor that includes the AFSRM of the first aspect of the invention. fifteen

    State of the art

    Nowadays, the switched reluctance machine (SRM) is of great interest, because it does not use permanent magnets, its construction is simple and robust, it has low manufacturing costs and high performance. From the point of view of electromechanical conversion, the switched reluctance machine is a rotating device with protruding poles in the stator and the rotor and unique excitation that normally works strongly saturated. The torque is produced by the tendency of the rotor to move towards a position in which the inductance of the excited phase winding is maximized, that is, to achieve the alignment of the stator poles with those of the rotor. For this, a power converter is necessary, with solid state switches, which generate the correct phase switching sequence for which it is necessary to know the position of the rotor. In variable speed applications, the switched reluctance machine operates in one of three control modes: 30 current mode, voltage mode and single pulse mode. Generally, the control of the switched reluctance machine is carried out in the low speed range, by means of current control, maintaining the current within a hysteresis band or by voltage control using pulse width modulation (PWM). At high speeds, the conduction period and the current waveforms adopt the natural characteristic, in accordance with the speed and torque requirements.
     Typically, rotary switched reluctance machines are radial flow machines, in which the air gap flow is in the radial direction relative to the axis of rotation. This type of SRM generally has a cylindrical shape with an external stator and an internal rotor in the most common arrangement, although they can also be arranged in reverse, with an internal stator and an external rotor. The axial flow rotary switched reluctance machine (SRM) is less usual, and in it the air gap flow is mainly parallel to the axis of rotation. The stator and rotor are parallel plates arranged perpendicular to the axis of rotation.
     10 Recently, some studies carried out in axial flow switching reluctance motors show that with this type of machine it is possible to obtain a higher torque density than in radial flow switched reluctance machines. These better characteristics of the axial flow switching reluctance machine are due to the increase in volume that includes the area of the air gap, an increase that depends mainly on the diameter of the machine, while in the radial type machine the volume that includes the Air gap area depends mainly on the length of the machine.

    The magnetic circuit of axially switched reluctance machines has some drawbacks related to their construction, being difficult to build using laminations.
     Although the first axial variable reluctance motor was proposed by Unnewher and Koch as early as 1973, recently, some authors have made important contributions to the development of axial flow switched reluctance machines (AFSRM). Some of said axial flow switched reluctance machines are described in US5925965, US2002104909A1, US20100295389A1, US20140252913A1, and also in the following articles:
     30
    - L. E. Unnewehr and W.H. Koch. “An Axial Air — Gap reluctance Motor for Variable Speed Applications.” IEEE Transactions on Power Apparatus and Systems, Vol 93, issue 1, January / February 1974

    - H. Arihara and K. Akatsu. ”Basic properties of an axial-type switched reluctance motor”. 35 IEEE Transactions on Industry Applications, Vol 49, No 1, January / February 2013.

    - A. Labak, N.C. Kar. "Designing and prototyping a novel five-phase pancake-shaped axial flux SRM for electric vehicle application through dynamic FEA incorporating flux-tube modeling." IEEE Transactions on Industry Applications, Vol. 49, No 3, May / June 2013. 5

    - R. Madhavan, B.G. Fernandes “Axial flux segmented SRM with a higher number of rotor segments for electric vehicles”. IEEE Transactions on Energy Conversion, Vol. 28, No 1, March 2013.
     10
    - T. Lambert, M. Biglarbegian, S. Mahmud. "A novel approach to the design of axial-flux switched reluctance motors". Machines 2015.3, 27-54; doi: 10: 10.3390 / machines3010027.

    - S. Murakami, H. Goto, O. Ichinokura. "A Study about Optimum Stator Pole Design of 15 Axial-Gap Switched Reluctance Motor." 21th International Conference of Electrical Machines (ICEM), 2-5 September 2014, Berlin, Germany.

    - T. Kellerer, O. Radler, T. Sattel, S. Purfürst. "Axial type switched reluctance motor of soft magnetic composite". Innovative Small Drives and Micro-Motor Systems, 19-20 September 20, 2013, Nuremberg, Germany.

    - J. Ma, R. Qu, J. Li. "Optimal design of an axial flux switched reluctance motor with grain oriented electrical steel". 18th International Conference on Electrical Machines and Systems (ICEMs), 25-28 October 2015, Pattaya City, Thailand. 25

    Arihara et al. present the basic design methodology for the axial counterpart of the classic rotary SRM. Murakami et al., Have studied the optimization of a SRM of 18/12 (stator poles / rotor poles) with air gap.
     30
    Madahvan et al. they have contributed to the development of the axial alternative of the segmented rotor SRM in a machine with two rotors and a stator with toroidal winding. Labak et al. they have proposed a new multiphase, cake-shaped SRM machine, with a stator consisting of a series of C-cores, each with a single coil wound on it, arranged perpendicularly to a rotor made of aluminum in which 35 have added an adequate number of hubs, the rotor poles, of material
    High permeability In this machine, torque production is due to the tendency of either of these cubes to align with the two poles of a C-core of the stator that has been energized. Some authors have exposed the manufacturing problems of these machines and have proposed to use different materials to build their magnetic circuit as an oriented grain electric sheet, Ma et al .; 5 soft magnetic compound, Kellerer et al .; and soft magnetic compound of sintered laminations, Lambert et al.
     Normally, the magnetic flux lines that circulate through the aforementioned AFSRM poles follow long magnetic flux paths, since each of them generally passes through two diametrically opposite stator poles.
     However, some efforts have been made to reduce the length of these magnetic flux paths and provide shorter magnetic flux paths, 15 since the reduction of these paths and the non-reversal of magnetic flux direction results in the reduction of Losses in iron. Thus, the AFSRM proposed by A. Labak et al. It has short magnetic flux paths but uses a cumbersome arrangement of C-nuclei in the stator and cubes in the rotor. T. Lambert et al., Propose combinations of stator and rotor that result in a short flow path, but in the case of having a second rotor would result in two magnetic flow paths. The toroidal winding arrangement, presented by R. Madhavan et al., Generates two magnetic flux paths that each cover the stator and one of the opposite rotors, but return both through the crown of the stator. 25
     Therefore, the AFSRMs discussed in the aforementioned articles are clearly improvable, both in terms of the length of the magnetic flux paths provided as well as with respect to their structure, distribution and arrangement of the rotor poles and / or the stator 30

    Description of the invention

    It is necessary to offer an alternative to the state of the art that covers the gaps found therein, providing an improved AFSRM, which allows shorter flow paths to pass through its poles.

    To this end, the present invention relates, in a first aspect, to an axial flow switched reluctance machine (AFSRM), which comprises, in a manner known per se:
     5
    - a stator comprising stator poles distributed along a first circumferential path in a stator plane;
     - electromagnet coils wound in at least some of said stator poles; Y
     10 - a rotor comprising rotor poles distributed along a second circumferential path in a rotor plane orthogonal to the axis of rotation, parallel to said stator plane and separated from it by a space along said axis of rotation , so that for some rotational positions of said rotor with respect to the axis of rotation, at least a portion of a rotor pole is faced with at least a portion of a pole of the stator.
     Generally, the space referred to is an air-occupied air gap, although other means than air can be used to occupy said space, such as other types of gases. twenty

    Unlike the AFSRM known in the state of the art, where the poles of both the stator and the rotor are distributed equidistant along their respective circumferential paths, in the AFSRM proposed by the first aspect of the invention, in a characteristic way, at least the stator poles or the 25 rotor poles are unequally distributed along said first and second circumferential paths, respectively.
     Depending on how the construction is done, the machine described by the first aspect of the invention functions as an electric motor or as an electric generator.
     For a preferred embodiment, the stator poles are distributed non-equidistantly along the first circumferential path and the rotor poles equidistantly along the second circumferential path. 35
     According to an embodiment of the machine of the first aspect of the invention, the stator poles are spatially arranged in pairs along the first circumferential path, in which the elements corresponding to each pair of stator poles are angularly separated one on the other, an angle , arranged in 5 clockwise direction as the first and second members, and in which the first member of each of the pairs of stator poles is angularly separated from the first of each contiguous pair of stator poles a angle  that has a value greater than that angle .
     10
    For one embodiment, the rotor poles must be angularly separated from each other, along the second circumferential path, an angle  of equal value to the result of subtracting the value of angle  from the value of angle .

    The machine of the first aspect of the invention comprises, for one embodiment, at least one electromagnet coil for each stator pole, where the electromagnet coil that is wound on the stator pole of each pair of stator poles is connected electrically in series with the electromagnet coil wound on the adjacent stator pole of the adjacent pair of stator poles forming a phase winding. twenty

    For a basic variant of said embodiment, each phase winding is formed only by said two electrically connected electromagnet coils. This is the case of a machine that includes three electrical phases and the stator has only three pairs of stator poles, each with a corresponding electromagnet coil 25 wound therein and interconnected as described in the previous paragraph, so three phase windings are formed, each with two respective electrically connected electromagnet coils.
     For a more elaborate variant of said embodiment, at least two electro-magnet coils connected electrically in series and wound in two corresponding first adjacent stator poles of two adjacent pairs of stator poles form a phase winding for the same electrical phase as two electromagnet coils electrically connected in series and wound in two corresponding second adjacent stator poles of two adjacent pairs of stator poles 35
    arranged in the first circumferential trajectory diametrically opposed with respect to said first adjacent stator poles.
     This is the case, for example, when the machine includes three electrical phases and the stator has six or more pairs of stator poles, each with a corresponding 5 electromagnet coil wound on it and interconnected according to said variant plus made of said embodiment, so that six or more windings are formed, each by two respective electrically connected electromagnet coils, wherein each winding must be electrically connected to a diametrically opposite winding to form the same electrical phase. 10

    Although for one embodiment, the machine of the first aspect of the invention comprises only a stator and a rotor, configured as described above, for a preferred embodiment:
     15 - the stator comprises additional stator poles distributed along a third circumferential path in an additional stator plane that is parallel and opposite the above-mentioned stator plane;
     - and in which the machine comprises an additional rotor comprising rotor poles 20 distributed along a fourth circumferential path in an additional rotor plane that is parallel to said additional stator plane and is separated from it by a space at along the axis of rotation, such that for some rotational positions of said additional rotor around the axis of rotation, at least a portion of an additional rotor rotor pole is faced with at least a portion of said stator poles additional.

    Generally, said space is also an air-filled air gap, although other means other than air can be used to occupy said space, such as other types of gases. 30
     For other embodiments, the machine of the first aspect of the invention comprises more than one stator and more than two rotors, arranged as said stator and said rotor and said additional rotor of the embodiment described in the preceding paragraph.
     For a variant of said preferred embodiment, the additional stator poles are
    also arranged spatially in pairs along the third circumferential path, and the machine comprises electromagnet coils wound on the additional stator poles, at least one electromagnet coil for each additional stator pole, where the electromagnet coil wound on each Additional stator pole is electrically connected in series with the electromagnet coil wound on the respective opposite stator pole of the opposite stator plane, to form the same phase winding with it, so that for each phase winding, when current is circulated through it, a single magnetic flux loop is closed between two rotor rotor poles, two stator poles, two additional stator poles and two additional rotor poles of the additional rotor. 10
     Generally, the rotor and / or the additional rotor comprise a rotor support member of which the rotor poles or the additional rotor poles protrude towards the stator, in which the rotor poles or the additional rotor poles are attached or integrated with said support member. The support member is made of a ferromagnetic material that allows the above-mentioned single magnetic flux to circulate therethrough between the two corresponding rotor poles or the two additional rotor poles.
     For one embodiment, the stator comprises a stator support member from which the stator poles protrude towards the rotor, or from which both the stator poles and the additional stator poles protrude, from opposite faces of the stator support member , substantially the same distance (although the present invention also covers different distances for other less preferred embodiments), towards the rotor and towards the additional rotor, respectively. 25

    According to one embodiment, the rotor support member is an annular or circular ferromagnetic part (or a plurality of straight or curved individual parts that interconnect two or more rotor poles), the rotor poles and / or the rotor poles Additional are also made of ferromagnetic material, and the stator support member is an annular or circular piece (or a plurality of straight or curved individual pieces that interconnect two or more stator poles or additional stator poles), and the poles Stator and / or additional stator poles are made of ferromagnetic material.
     35 For the aforementioned embodiment for which the machine of the first
    aspect of the invention comprises only a stator and a rotor, the above-mentioned stator support member is made of ferromagnetic material, so that a magnetic flux path can circulate therethrough when it passes from a stator pole to the adjacent one.
     5 On the contrary, for those embodiments in which the machine of the first aspect of the invention comprises two or more rotors, and therefore the magnetic flux paths do not circulate through the stator support but through the rotor supports , the above-mentioned stator support member is made of a non-magnetic material. 10
     The construction of the magnetic circuit of the axial flow reluctance machine is a challenge, given the difficulty of doing so using laminations. Therefore, for a preferred embodiment, the stator and the rotors of the machine of the first aspect of the present invention are constructed using sintered parts made of SMC, (Soft Magnetic Composites): Soft magnetic compounds. SMCs are separate iron dust particles with an electrically insulated layer. Basically, SMCs offer a unique combination of magnetic saturation and low eddy current losses, enabling 3D flow distribution and facilitating the production of 3D parts in a cost-effective manner, using powder metallurgy.

    The machine of the first aspect of the invention can be used for many applications, but it is especially intended for a direct drive motor located inside a wheel. 25
     According to one embodiment, the machine described by the first aspect of the invention further comprises a tree fixed to the stator.

    A second aspect of the present invention relates to an electric vehicle, which comprises:
     - an electric motor that includes the machine of the first aspect of the invention;
     - a source of electrical energy; 35
     - an electronic control system powered by said power source, and with output terminals connected to free terminals of said electromagnet coils to provide them with electrical control signals to control the operation of the machine, and
     - at least one wheel mechanically coupled to at least the rotor of the machine to rotate with it under the control of said electronic control system

    Brief description of the drawings 10
     The foregoing and other advantages and features will be better understood from the detailed description of the following embodiments, with reference to the accompanying drawings, which should be considered in an illustrative and non-limiting manner, in which:
     Figure 1 is a schematic side view of the axial flow switched reluctance machine of the first aspect of the invention, for an embodiment of the machine that is formed by a rotor and a stator;
     Figure 2 is a front view of the AFSRM stator of the first aspect of the present invention, taken from the space between the stator and the rotor, for an embodiment for which the stator comprises six poles distributed in a non-equidistant manner. along a circumference and with respective electromagnet coils electrically interconnected with each other to form three phase windings; 25
     Figure 3 is a front view of the AFSRM rotor of the first aspect of the present invention, showing the space between the stator and the rotor, for the same embodiment of Figure 2, in which the rotor comprises five equidistantly distributed poles. along a circle; 30
     Figure 4 is a schematic side view of the AFSRM of the first aspect of the invention, for an embodiment where the machine comprises two rotors and a stator with stator poles protruding towards the poles of both rotors;
     35 Figure 5 is a schematic perspective and exploded view of the AFSRM of the
    First aspect of the invention, for the same embodiment of Figure 4, in which one of the short magnetic flux paths, which passes through four stator poles and two poles of each of the two, is shown with a broken line. two rotors;
      5 Figure 6 schematically shows a portion of the rotors and stator of Figure 5, including the poles through which the magnetic flux that is also shown passes, schematically showing the electrical connection of the coils wound on the stator poles ( which has been omitted in Figure 5, for clarity) and which constitute what has been referred to herein as a double electromagnet through which the magnetic flux passes;
     Figure 7 is a perspective view of the AFSRM of the first aspect of the invention once mounted on a housing, for one embodiment;
     Figure 8 is a schematic block diagram of a complete drive system that includes the AFSRM of the first aspect of the invention, an electronic power converter electrically connected to the coils thereof, a control unit and a position transducer / speed arranged to detect the position / speed of the rotation of the rotor (s) of the AFSRM; twenty

    Figure 9 is a diagram of the electronic power converter of the drive system of Figure 8, for one embodiment;

    Figure 10 schematically shows a distribution of the magnetic field lines 25 for the linear machine derived from the AFSRM of the first aspect of the invention, for the arrangement of Figure 5, calculated using 2D-FEA ("Finite Element Analysis") );
     Figure 11 is a diagram showing the required torque on the wheel with respect to the speed and the slope, showing the torque-speed envelope to be provided by the motor drive system including the AFSRM of the first aspect of the invention to be been designed by the present inventors, for its realization;
     Figure 12 shows the AFSRM magnetization curves obtained using 2D-FEA for the linear machine of Figure 9;
     Figure 13 shows the static torque curves of the AFSRM obtained using the 2D-5 FEA for the linear machine of Figure 9;
     Figure 14 shows the waveforms, phase voltage, phase current, DC bus current, phase torque and total torque (thin line curve at the bottom of the graph) for an average torque of 122 Nm at 300 rpm, obtained from 10 mathematical simulations with the AFSRM of the first aspect of the invention, for the designed drive system, carried out in Matlab-Simulink and using the results of 2D-FEA;
     Figure 15 shows the same type of waveforms as in Figure 14, also obtained from mathematical simulations with the AFSRM of the first aspect of the invention, for the designed drive system, but for an average torque of 70 Nm at 600 rpm; Y
     Figure 16 is a graph showing a comparison between the expected values of the torque-speed envelope and the simulated values (triangular marks) with the AFSRM of the first aspect of the invention, for the designed drive system.

    Detailed description of various embodiments
     25
    Figure 1 shows a basic embodiment of the AFSRM of the first aspect of the invention, for which it comprises:

    - a stator S comprising a stator support member Ms in the form of an annular ferromagnetic part from a face from which the stator poles p1 30 distributed along a first circumferential path in a stator plane toward a rotor extend R;
     - electromagnet coils L wound on each stator pole p1;
     35 - a rotor R comprising a rotor support member Mr in the form of a part
    annular ferromagnetic from a face of which the rotor poles p2 protrude towards the stator S, and are distributed along a second circumferential path in a rotor plane that is orthogonal to a rotation axis, parallel to said plane of stator and separated from it by a space along said axis of rotation, so that for some rotational positions of said rotor R around said axis of rotation at least a portion of a rotor pole p2 faces the minus a portion of a stator pole p1; Y
     - a shaft E fixed to the stator S, particularly to the stator support member Ms, and mounted on the rotor support member Mr through a bearing in the central opening 10 thereof.
     For the embodiment illustrated in Figure 2, the stator S comprises six poles p1 distributed unequally along the first circumferential path, spatially arranged in pairs along it (the oval 15 represented in a broken line encompasses one of said pairs), where the members of each of the pairs of stator poles p1 are angularly separated from each other by an angle , following the clockwise direction as first and second members, where the first member of each of said pairs of stator poles p1 is angularly separated from the stator poles 20 at an angle  of a value greater than the angle ángulo with respect to the first member of each adjacent pair 20.
     The electromagnet coils L of the stator S of Figure 2 are electrically interconnected to form three phase windings W1, W2 and W3, as can be seen in the figure, that is, the electromagnet coil L wound on the stator pole p1 of 25 each pair of stator poles p1 is electrically connected in series with the electromagnet coil L wound on the adjacent stator pole p1 of the adjacent pair of stator poles p1 forming a phase winding. Each phase winding W1, W2 and W3 has two free ends that constitute the respective terminals through which the electrical control signals will be applied when connected (connections 30 not shown) to the electronic power converter (see Figure 8) .

    Figure 3 is a front view of the AFSRM rotor of the first aspect of the present invention, taken from the space between the stator and the rotor, for the same embodiment of Figure 2, where the rotor comprises five poles p2 distributed equidistantly to 35 along the second circumferential path, and angularly separated one of
    another an angle  of equal or substantially equal value to the result of subtracting the value of angle  from the value of angle .

    A more elaborate embodiment of the AFSRM of the first aspect of the invention is shown in Figures 4 and 5, in which:
     - the stator S comprises additional stator poles p3 distributed along a third circumferential path in an additional stator plane that is parallel and opposite to said stator plane;
     10 - and in which the machine has an additional rotor Rf comprising an additional rotor support member Mrf also in the form of an annular ferromagnetic part, from a face of which the additional rotor poles p4 protrude towards the stator S and are distributed along a fourth circumferential path in an additional rotor plane that is parallel to the additional stator plane and is separated from it by a space along the axis of rotation, so that for some rotation positions of the additional rotor Rf around the axis of rotation, a portion of an additional rotor pole p4 of the additional rotor Rf is faced with a portion of one of the additional stator poles p3.
     In the case of the embodiment shown in Figure 5, the axis E crosses the additional rotor Rf (particularly the support member of the additional rotor Mrf), is connected with the stator S (to the support member Ms which is made of material non-magnetic) and is mounted on the two rotor support members s, Mrf in the central opening thereof using bearings. 25
     The angles , , and  mentioned above are also valid for the distribution of poles of the embodiment referred to in Figure 5.
     Said angles and also other AFSRM parameters of the first aspect of the invention, which must be met for preferred embodiments, are described below.
     For said preferred embodiments, the number of additional stator poles p3 is equal to the number of stator poles p1 and together, with the electromagnet coils L 35 wound on them, they form z double electromagnets, where the total number NS of
    stator poles S, including stator poles p1 and additional stator poles p3, is determined according to the number of electrical phases m of the machine, all following the following relationships:

    = 5 = 2 = 2

    where k is an integer called multiplicity.

    For said preferred embodiments, the number of rotor poles p2 is equal to the number of additional rotor poles p4 and equal to NR, defined by the formula:
      = (2 - 1)

    where:

     15 Zº360

    and where:
     RRNmkmkN)) ((º360

    The above relationships are also valid for the realization of Figure 2, where k 20 = 1, Z being in this case the number of simple electromagnets, NS the total number of stator poles p1 and NR the number of rotor poles p2.
     The preceding expressions regarding angles for 3 and 4 phase machines (m) are shown in the following table:

     k  m Z NS NR α (o) ϒ (o) δ (o)
     one  3 3 6 5 72.00 120.00 48.00
     2  3 6 12 10 36.00 60.00 24.00
     3 3  9 18 15 24.00 40.00 16.00
     4  3 12 24 20 18.00 30.00 12.00
     one  4 4 8 7 51.43 90.00 38.57
     2  4 8 16 14 25.71 45.00 19.29
     3  4 12 24 21 17.14 30.00 12.86
     4 4  16 32 28 12.86 22.50 9.64

    In figures 5 and 6 one of the short magnetic flux paths is shown, which passes through four stator poles p1 and two poles p2 and p4 of each of the two rotors R, Rf, particularly when current flows through one of the windings W1, that is to say by the coils L of a double electromagnet. It can be seen that the flow path also circulates through the rotor support members Mr and Mrf.

    The flow lines join the stator poles p1, p3 on both sides of the stator S with the poles p2, p4 of the two rotors R, Rf force the alignment of these poles. 10

    Figure 6 is a schematic view of a double electromagnet showing how its coils L are connected in the aligned position. In the case of k> 1, the windings of the phases are obtained by properly connecting the Z different double electromagnets of each phase. fifteen

    Although not shown, for the embodiment of Figure 5, two electromagnet coils L electrically connected in series and wound in two corresponding adjacent stator poles p1 of two adjacent pairs of stator poles p1 form a phase winding W1, W2, W3 for the same electric circuit phase as two coils of 20 electromagnet L electrically connected in series and wound in two corresponding adjacent stator poles p1 of two adjacent pairs of stator poles p1 arranged in the first circumferential path diametrically opposed with respect to said first adjacent p1 stator poles. In other words, the phase winding W1 shown in Figure 6 is electrically connected in series to a phase winding diametrically opposed to it. The same applies to the rest of the windings of phase W2, W3, thus constituting an AFSRM for three electrical phases, where each electrical phase will be connected to an electrical circuit consisting of eight coils connected in series.
     Figure 7 shows a possible final embodiment of the AFSRM of the first aspect of the invention once mounted in a housing H.
     Preferably, the E axis is a hollow shaft through which at least the electric cables (not shown) that connect the phase windings W1, W2, W3 with the electronic power converter pass.
     5
    Although the stator poles p1, p3 and the rotor poles p2, p4 shown in the figures, have a triangular cross section, other shapes of cross section are also encompassed by the present invention, for other embodiments (not shown), such as round, square, rectangular or trapezoidal.
     10
    In order to obtain a continuous torque, the different phases of the machine must be activated properly. To do this, as indicated above, the AFSRM must be powered by an electronic power converter controlled by a switching sequence (control) generator based on the relative position between stator and rotor which is obtained from a position transducer /speed. Figure 8 15 shows a schematic block diagram of the entire drive system, which includes an electronic power converter that is electrically connected to the coils L, a control unit and a position / speed transducer arranged to detect the position / Rotation speed of the rotor (S) of the AFSRM.
     twenty
    Figure 9 shows a diagram of the electronic power converter for the case of a three-phase machine. The electronic power converter has as many branches as phases, each branch is formed by two switches, IGBTs in the case of Figure 9, and two diodes arranged as shown in Figure 9. When a phase is activated, the two switches are they activate and the current flows through the machine phase, from the power source, the phase voltage being equal to the power supply voltage. When the two switches are disconnected, the current continues to circulate through the phase, but through the diodes, the voltage being at the opposite polarity phase of the power supply voltage, thus allowing demagnetization of the phase. For this to happen, the control must generate the appropriate 30 activation signals of the switches, switching them according to the relative position between the stator and rotor poles, determined by a position / speed transducer and according to the needs of the load.

    The control generates suitable signals for activating the switches according to the relative position between the stator and rotor poles, determined by a
    position / speed transducer, and according to the needs of the load. In the low speed range, the axial flow switched reluctance machine is controlled by current control, maintaining the current within a given hysteresis band or by voltage control using PWM, in any of the methods chosen during the period of driving one or both switches can chop (open and close 5) according to the control strategy. At high speeds, both switches remain activated during the driving period and the current waveforms adopt the natural form according to the speed and torque requirements. When specific controls are needed, for example, if torque curling is to be minimized, the activation and blocking angles are carefully selected, 10 according to the programmed control mode depending on the speed and torque required by the load.
     The inventors have designed a drive system that includes an engine that implements the AFSRM of the first aspect of the invention as will be described below.

    DRIVE SYSTEM REQUIREMENTS:

    An engine for an e-scooter must be designed to provide the torque and speed requirements appropriate for the size and driving conditions of the scooter to be driven. In addition, engine performance should allow reasonable autonomy for each battery charge. The determination of the torque-speed envelope is the first step in the design process of a traction motor. The engine must provide enough torque to overcome rolling resistance, aerodynamic drag and scooter weight when climbing a slope. In addition, you must provide sufficient torque for acceleration. Therefore, the dynamic equation of motion of a scooter vehicle is given by:

    Where: 30 T, is the torque on the wheel (Nm) m, is the total mass of the scooter (kg) , is the angle of inclination R, is the radius of the tire (m)
    μr, is the coefficient of rolling resistance g, is the acceleration of gravity (m / s2) ρ, is the density of air (kg / m3) A, is the frontal area (m2) v, is the velocity of scooter (m / s) 5 v0. is the wind speed (m / s) CD, it is the coefficient of aerodynamic drag km, it is the coefficient of inertia

    The angle of inclination and the slope in percentage (p) are related by: 10
    The present inventors have designed a direct drive drive system for the motorization of an e-scooter with the parameters of Table I. The requirements to be verified by the engine are summarized in Table II.
     fifteen
    TABLE I. Main parameters of the proposed e-scooter:
     Parameters  Values
     m (kg)  200
     ρ, (kg / m3)  0.01
     CD  1.23
     R (m)  0.7
     A (m2)  0.2387; 130 / 60-13 ”
     km  0.6


    TABLE II Main engine requirements:
     Requirements  Values
     Speed (maximum)  80 km / h (̴ 900 rpm)
     Tension  48/72 V
     Par at 45km / h  75Nm
     Pending at 20km and corresponding pair  > 35%; 170 Nm
     Power  4 kW (20 <v <80 km)
     performance  > 88% for a wide range of speeds


    Therefore, according to the values shown in the previous tables and equations (1-2), the torque-speed envelope that the drive must provide is shown in Fig. 11. 5


    DESCRIPTION OF THE DESIGNED AFSRM:

    As indicated above, in order to verify that the proposed axial flow switched reluctance motor 10 meets the requirements of Table II, a motor has been designed to achieve power densities similar to those of synchronous motors. permanent magnet with external rotor, currently used for the propulsion of e-scooters (250 W / kg). The outer dimensions of the motor are limited to a diameter of 308 mm and an axial length of 116 mm so that it can fit within a 13 "(33.02 cm) wheel. The axial flow switched reluctance motor designed accordingly with the embodiment shown in Figure 5, that is, with a stator S of twelve poles p1, p2 per side, and two rotors R, Rf each with ten poles and with the configuration given below in Table III.
     20 TABLE III. Engine configurations designed:

    As is well known, the benefits of switching reluctance machines are very sensitive to the length of the air gap, so the air gap has been limited to 0.5 25 mm and constructive measures have been taken to ensure this value and to avoid air gaps. uneven on both sides of the stator.

    ELECTROMAGNETIC ANALYSIS OF THE DESIGNED AFSRM:
     30
    The study of axial flow machines involves a three-dimensional electromagnetic problem. Therefore, the most accurate solution for modeling the machine is with the three-dimensional finite element method, 3D-FEM. However, this method consumes a lot of time, and both the definition of the problem and the resolution process are quite cumbersome. 5

    A proven alternative is to perform simulations using 2D-FEM by taking 2D planes of the machine's geometry in different radii. This means transforming the axial flow machine into a linear machine. The distribution of the magnetic field lines of the resulting linear machine for the mean radius of the stator is shown in Figure 10. The magnetization curves and static torque curves obtained, using this methodology, are shown in Figs. 12 and 13, respectively.

    SIMULATION OF THE AFSRM DESIGNED DRIVING SYSTEM:
     fifteen
    The drive system to be simulated includes all the elements shown in Figure 8, that is, the AFSRM, the power converter, an asymmetric converter (classic converter) with two switches and two diodes per phase (as shown in Figure 9 ), a control unit and a position / speed sensor. The control due to the limited speed range (0 to 900 rpm) is a hysteresis control with variable activation angles (θON) and variable locking angles (θOFF) and has been implemented in Matlab-Simulink using the results of the element analysis finite of the AFSRM. The waveforms of the phase voltage, phase current, bus current and total torque are shown in Fig. 14 for an average torque of 122 Nm at 300 rpm with θON = -5º and θOFF = 17º, and in the Fig. 15 for an average torque of 70 Nm at 600 rpm with θON = - 2º and θOFF = 14º. 25 In Fig. 16, the expected torque-velocity envelope of the e-scooter is compared with the results obtained from the simulation.

    The results of the previous simulations show that the performance of the designed drive system closely approximates the requirements of the e-30 scooter. However, due to the remarkable torque curling, it would be advisable to switch to direct torque control strategies.

    One skilled in the art could introduce changes and modifications to the described embodiments without departing from the scope of the invention as defined in the appended claims.
    权利要求:
    Claims (16)
    [1]

    1.- Axial flow switched reluctance machine, comprising:
    - a stator (S) comprising stator poles (p1) distributed along a first circumferential path in a stator plane;
    - electromagnet coils (L) wound in at least some of said stator poles (p1); Y
     10
    - a rotor (R) comprising rotor poles (p2) distributed along a second circumferential path in a rotor plane orthogonal to the axis of rotation, parallel to said stator plane and separated therefrom by a space along of said axis of rotation, so that for some rotational positions of said rotor (R) around said axis of rotation, at least a portion of a rotor pole (p2) is faced with at least a portion of a pole of stator (p1);
    characterized in that at least said stator poles (p1) or said rotor poles (p2) are unequally distributed along said first and second circumferential paths, respectively. twenty

    [2]
    2. Machine according to claim 1, wherein said stator poles (p1) are distributed non-equidistant along said first circumferential path and said rotor poles (p2) are distributed equidistant along said second circumferential trajectory 25

    [3]
    3. Machine according to claim 1 or 2, wherein the stator poles (p1) are spatially arranged in pairs along the first circumferential path, wherein the members of each pair of stator poles (p1) an angle δ is angularly separated from each other, arranged clockwise as 30 first and second members, and in which the first member of each of said pairs of stator poles (p1) is angularly spaced apart from to the first member of each adjacent pair of stator poles (p1) by an angle γ, which has a value greater than the value of said angle .
     Machine according to claim 3, in which the rotor poles (p2) are separated
    angularly from each other, along said second circumferential path, an angle  having a value that is equal to or substantially equal to the result of subtracting the value of said angle  from the value of said angle .

    [5]
    5. Machine according to claim 3 or 4, comprising at least one coil of 5 electromagnet (L) per stator pole (p1), wherein the electromagnet coil (L) wound on the stator pole (p1) of each pair of stator poles (p1) is electrically connected in series with the electromagnet coil (L) wound on the adjacent stator pole (p1) of the adjacent pair of stator poles (p1) that form a phase winding ( W1, W2, W3). 10

    [6]
    6. Machine according to claim 5, wherein two electromagnet coils (L) electrically connected in series and wound in two corresponding first adjacent stator poles (p1) of two adjacent pairs of stator poles (p1) form a winding phase (W1, W2, W3) for the same electrical phase as two 15 electromagnet coils (L) electrically connected in series and wound in two corresponding second adjacent stator poles (p1) of two adjacent pairs of stator poles (p1) ) arranged in the first circumferential trajectory diametrically opposed with respect to said first adjacent stator poles (p1). twenty

    [7]
    7. Machine according to any of the preceding claims, wherein;
    - said stator (S) comprises additional stator poles (p3) distributed along a third circumferential path in an additional stator plane parallel and opposite to said stator plane;
     - and wherein the machine comprises an additional rotor (Rf) comprising additional rotor poles (p4) distributed along a fourth circumferential path in an additional rotor plane that is parallel to said additional stator plane and which 30 is separated from it by a space along the axis of rotation, so that for some rotational positions of said additional rotor (Rf) around the axis of rotation at least a portion of an additional rotor pole (p4) of the additional rotor (Rf) is faced with at least a portion of one of said additional stator poles (p3). 35

    [8]
    8. Machine according to claim 7, when it depends on claim 5 or 6, wherein the additional stator poles (p3) are also arranged spatially in pairs along the third circumferential path, and where the machine comprises coils of electromagnet (L) wound on the additional stator poles (p3), at least one electromagnet coil (L) for each additional stator pole (p3), where the 5 electromagnet coil (L) wound on each pole of Additional stator (p3) is electrically connected in series with the electromagnet coil (L) wound on the respective opposite stator pole (p1) of the opposite stator plane, to form the same phase winding (W1, W2, W3) with the same, so that for each phase winding (W1, W2, W3), when current is circulated through it, a single flow loop is closed between two rotor poles (p2) of the rotor (R), two stator poles (p1), two additional stator poles (p3 ) and two additional rotor poles (p4) of the additional rotor (Rf).
    [ 9]
     9. Machine according to claim 8, wherein the number of additional stator poles 15 (p3) is equal to the number of stator poles (p1) and together, with the electromagnet coils (L) wound on themselves, Z forms double electromagnets, where the total number NS of stator poles (S), including stator poles (p1) and additional stator poles (p3), is given according to the number of electrical phases of the machine, m, through the following relationships: 20
      = = 2 = 2
    where k is an integer called multiplicity,
    where the number of rotor poles (p2) is equal to the number of additional rotor poles 25 (p4) and equal to NR, defined by the formula:
      = (2 - 1)
    where:
     30
    and where:

    [10]
    10. Machine according to any of claims 7 to 9, wherein said rotor (R) and / or additional rotor (Rf) comprise a rotor support member (Mr, Mrf) of which the rotor poles (p2) or additional rotor poles (p4) protrude towards the stator (S), 5 where the rotor poles (p2) or the additional rotor poles (p4) are joined or integrated with said support member (Mr, Mrf).

    [11]
    11. Machine according to any of claims 7 to 10, wherein said stator (S) comprises a stator support member (Ms) of which the stator poles (p1) 10 protrude towards the rotor (R), or from which both the stator poles (p1) and the additional stator poles (p3) protrude, from opposite faces of the stator support (Ms), substantially the same distance, towards the rotor (R) and towards the additional rotor (Rf ), respectively.
     12. Machine according to claim 11 when dependent on claim 10, wherein said rotor support member (Mr, Mrf) is an annular or circular ferromagnetic part, the rotor poles (p2) being made and / or the additional rotor poles (p4) also of a ferromagnetic material, and wherein said stator support member (Ms) is a non-magnetic ring or circular piece, the stator poles (p1) and / or the poles being of additional stator (p3) made of a ferromagnetic material.

    [13]
    13. Machine according to any of claims 1 to 6, wherein said rotor (R) comprises a rotor support member (Mr) from which the rotor poles (p2) protrude towards the stator (S), where the rotor poles (p2) are joined or integrated with said support member (Mr).

    [14]
    14. Machine according to any of claims 1 to 6, or according to claim 13, wherein said stator (S) comprises a stator support member (Ms) from which the stator poles (p1) protrude towards the rotor (R). 30

    [15]
    15. Machine according to claim 14, comprising only a stator (S) and a rotor (R), wherein said rotor support member (Mr) is an annular or circular ferromagnetic part, the rotor poles (p2) are also made of a ferromagnetic material, and where said stator support member (Ms) is a piece 35
    annular or circular ferromagnetic, the stator poles (p1) being made of a ferromagnetic material.

    [16]
    16. Machine according to any of claims 7 to 12, wherein at least said rotor poles (p2, p4) and stator poles (p1, p3) are made of sintered parts 5 of soft magnetic compounds.

    [17]
    17. Machine according to any of claims 1 to 6, wherein at least said rotor poles (p2) and stator poles (p1) are made of sintered parts of soft magnetic compounds. 10

    [18]
    18.- An electric vehicle, comprising:
    - an electric motor that includes the machine of any of the preceding claims; fifteen
     - a source of electrical energy;
    - an electronic control system powered by said electrical power source and with output terminals connected to free terminals of said electromagnet coils to provide them with electrical control signals to control the operation of the machine, and
    - at least one wheel, mechanically coupled to at least the rotor of the machine to rotate with it under the control of said electronic control system. 25
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    同族专利:
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    WO2018077788A1|2018-05-03|
    ES2666212B1|2019-03-19|
    引用文献:
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    ES201631377A|ES2666212B1|2016-10-26|2016-10-26|SWITCHED AXIAL FLOW RELUCTANCE MACHINE AND ELECTRIC VEHICLE COMPRISING THE MACHINE|ES201631377A| ES2666212B1|2016-10-26|2016-10-26|SWITCHED AXIAL FLOW RELUCTANCE MACHINE AND ELECTRIC VEHICLE COMPRISING THE MACHINE|
    PCT/EP2017/076976| WO2018077788A1|2016-10-26|2017-10-23|An axial flux switched reluctance machine and an electric vehicle comprising the machine|
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