JP5966409B2 - Rotating motor - Google Patents

Description

  The present invention relates to a structure for suppressing torque pulsation during energization of a rotary motor.

  In order to suppress torque pulsation that causes vibration and noise of the rotating motor, a skew structure is known in which the rotor is divided in the axial direction and the magnets are arranged with a phase difference around the rotation axis of each rotor. . For example, Patent Document 1 describes canceling cogging torque, which is torque pulsation during non-energization, by appropriately setting the number of stages and the phase shift angle in a multistage skew structure.

JP 2004-248422 A

  However, in the skew structure of Patent Document 1, since there is a phase difference in the magnet position of the rotor, the cogging torque, which is a torque pulsation during non-energization, can be canceled, but there is no phase difference in the current during energization. Sometimes there is a current phase difference corresponding to the phase difference of the magnet position between the skews. Therefore, the magnitude of torque ripple, which is torque pulsation that occurs during energization, differs at each stage. Therefore, the skew structure of Patent Document 1 cannot sufficiently cancel the torque ripple, and vibrations and noises generated by these excitation forces cannot be sufficiently suppressed.

  Therefore, an object of the present invention is to provide a rotary motor that can reduce torque ripple that occurs during energization.

The rotary electric motor according to the present invention is a rotary electric motor including a plurality of rotors having the same configuration with permanent magnets and a plurality of stators with coils. A plurality of rotors are arranged adjacent to each other so as to rotate synchronously in the same rotation direction on the same rotation axis, or a plurality of rotors are arranged adjacent to each other so that rotation axes are parallel and synchronously rotate in the same rotation direction. is to have a phase difference in the rotational direction between adjacent rotor is mounted on each rotor. In other words, the rotor is provided with a phase difference in the rotational direction by adopting a skew structure or by separating each stage of the skew structure so that the rotation axes are parallel and synchronously rotate in the same rotational direction . . To each slot or each of the teeth of the stator which is disposed at a position corresponding to each rotor is mounted coils in multiple phases to have a current phase difference in the rotational direction between adjacent stator. The coils of a plurality of phases are a basic basic phase and an additional phase different from the basic phase, and the combination of the basic phase and the additional phase is different in each slot or each tooth. The additional phase of each slot or each tooth is the phase having the smallest phase difference including the phase opposite to the basic phase in each of the phase advance direction and the phase delay direction.

  According to the present invention, the phase of the rotor in the rotational direction is shifted, and a plurality of phase coils are attached to each slot or each tooth of the stator so as to have a current phase difference between adjacent stators. The phase of the current flowing through the coil is also shifted. Thereby, the torque ripple at the time of electricity supply can be reduced.

FIG. 1 is a schematic configuration diagram of a system to which the first embodiment of the present invention is applied. 2A is a side view of the motor 1, FIG. 2B is a cross-sectional view taken along the line IIA-IIA in FIG. 2A, and FIG. 2C is a cross-sectional view taken along the line IIB-IIB. It is. 3A is a side view of a part of the stator, FIG. 3B is a view of FIG. 3A viewed from the rotating shaft side of the rotor, and FIG. 3C is IIIA- of FIG. 3A. FIG. 3D is a sectional view taken along the line IIIB-IIIB, and FIG. 3D is a sectional view taken along the line IIIB-IIIB. FIG. 4 is a diagram for explaining current synthesis. FIG. 5 is a diagram showing the result of combining the currents. FIG. 6 is a diagram showing the magnitude and phase of torque ripple at each stage after current synthesis. FIG. 7 is a diagram showing the magnitude and phase of the circular zero-order excitation force at each stage after current synthesis. FIG. 8 is a configuration diagram of a system to which the second embodiment is applied. FIG. 9A is a front view of the motor unit, and FIG. 9B is a side view of the same. FIG. 10A illustrates an example of a + skew side coil, and FIG. 10B illustrates an example of a − skew side coil. FIG. 11 is a diagram showing the result of combining the currents. FIG. 12 is a configuration diagram of a system to which the third embodiment is applied. FIG. 13A is a front view of the motor unit, and FIG. 13B is a side view of the same. FIG. 14A illustrates an example of a + skew side coil, and FIG. 14B illustrates an example of a − skew side coil. FIG. 15 is a diagram showing the result of combining the currents.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 1 is a schematic configuration diagram of a system to which the first embodiment of the present invention is applied. In this system, a direct current of the battery 2 is converted into a three-phase alternating current of U, V, and W by an inverter 3, and an alternating current synchronous motor (hereinafter simply referred to as “motor”) 1 is driven by the current.

  2A and 2B are diagrams showing the configuration of the motor 1. FIG. 2A is a side view of the motor 1, FIG. 2B is a cross-sectional view taken along the line IIA-IIA in FIG. C) is a sectional view taken along the line IIB-IIB. The magnets 12A and 13A, and the magnets 12B and 13B are alternately arranged so as to make one round of the outer circumferences of the rotors 11A and 11B, respectively, as shown in FIG. 2 (B) and FIG. 2 (C). However, FIG. 2A shows only a part thereof.

  The motor 1 is a concentrated winding motor having 16 poles and 24 slots. The rotor 11 of the motor 1 is divided into two in the axial direction. Magnets 12A and 13A are alternately arranged on the outer periphery of the left rotor 11A in the drawing, and magnets 12B and 13B are alternately arranged on the outer periphery of the right rotor 11B in the drawing. Has been. The magnets 12A and 12B and the magnets 13A and 13B are arranged so as to have a phase difference around the rotation axis of the rotor 11, respectively. That is, the rotor 11 has a divided skew in which the rotor 11A and the rotor 11B having the same structure are coupled so as to have a phase difference around the rotation axis.

  The stator 10 is also divided into two in the rotational axis direction. The coils 14A and 14B are provided in the teeth portion 15A of the stator 10A corresponding to the rotor 11A, and the coils 14A and 14B are provided in the teeth portion 15B of the stator 10B corresponding to the rotor 11B. 14C is wound. The coils 14A-14C will be described later.

  Here, the phase difference between the rotor 11A and the rotor 11B will be described.

  In the motor 1, the rotational order that is the least common multiple of the number of poles and the number of slots, in this embodiment, the 48th-order torque ripple that is a torque pulsation, and the circle in which the force in the same phase acts on all teeth 15 in the radial direction of the stator 10. Ring 0th order vibration force is generated. Therefore, if the phase difference of each stage is set so that they cancel each other out at the rotation order at which torque ripple and annular zero-order excitation force are generated in divided skew, torque ripple and annular zero-order excitation force can be reduced. Can be reduced. However, it is assumed that the drive current also has a phase difference similar to the skew. A method of providing the current phase difference will be described later.

  Here, since the division skew is two stages, the phase difference may be 180 degrees at the 48th-order frequency. Therefore, the phase difference between the magnets 12A and 12B and between the magnets 13A and 13B, that is, the phase difference between the rotor 11A and the rotor 11B is 360/48/2 = 3.75 degrees. This is 30 degrees in terms of electrical angle converted to the period of the drive current. Hereinafter, the phase advance side is referred to as + skew side, and the delay side is referred to as −skew side.

  3A and 3B are diagrams illustrating the structure of the stator 10, FIG. 3A is a side view of a part (U phase) of the stator 10, and FIG. 3B is a rotation shaft of the rotor 11. FIG. 3C is a sectional view taken along line IIIA-IIIA in FIG. 3A, and FIG. 3D is a sectional view taken along line IIIB-IIIB.

  The stator 10 has a configuration in which a plurality of T-shaped thin plates are stacked in the direction of the rotation axis of the rotor 11. There is no tooth portion in a predetermined range substantially in the center in the direction of the rotation axis, and the tooth portion is divided into two on the + skew side and the −skew side. The -V phase coil 14B as an additional phase is wound around the tooth portion 15A of the skew side stator 10A, and the -W phase coil 14C as an additional phase is wound around the tooth portion 15B of the skew side stator 10B. Is wound. A + U phase coil as a basic phase is wound around the outer periphery of the coils 14B and 14C.

  It should be noted that a phase with a-sign such as a -V phase or -W phase indicates that the polarity is opposite to the phase with a + sign, that is, the direction of current flow is opposite.

  The method of selecting the additional phase when winding not only the basic phase but also the additional phase coil and the operation when the additional phase is also wound will be described with reference to FIG. In FIG. 4, the vertical axis represents the current value, the horizontal axis represents the electrical angle, the + U phase as the basic phase, the + V phase, the + W phase, the −U phase, the −V phase, the −W phase, and the + U phase as the additional phases. It shows the current amplitude of the synthesized -V phase.

  When a coil of two different phases is wound around one tooth 15, the sum of the currents of those phases is equivalent to flowing through the tooth 15. Then, by combining the currents of the basic phase and the additional phase, the phase of the current amplitude is shifted to the advance side or the delay side. The deviation due to the synthesis is determined by the current ratio CR of the additional phase with respect to the basic phase. That is, the larger the current ratio CR, the greater the deviation.

  As described above, when the + U phase is the basic phase, any of the + V phase, + W phase, -U phase, -V phase, and -W phase can be added. As the phase difference between the basic phase and the additional phase is reduced, the synthesized current amplitude can be increased. Therefore, when the phase of the + U phase is to be advanced, the phase difference with respect to the + U phase is as small as 60 degrees in the advance direction. When combined with the -V phase, the current amplitude is maximized. Conversely, when the phase is delayed, the current amplitude becomes the largest when combined with the -W phase of 60 degrees in the delay direction in the phase difference. Therefore, in the present embodiment, as an additional phase to the basic phase + U phase, a −V phase coil is wound on the + skew side, and a −W phase coil is wound on the −skew side.

  The current ratio CR of the additional phase can be obtained by Expression (1).

Where θ0: phase difference of the additional phase relative to the basic phase
θ1: Phase difference of the combined current with respect to the basic phase In this embodiment, as described above, it is necessary to provide a phase difference of an electrical angle of 30 degrees on the + skew side and the −skew side. Shift the phase by 15 degrees. Therefore, if θ0 = 60 degrees and θ1 = 15 degrees, the current ratio CR is about 27%.

  The current ratio CR can be adjusted by the number of turns of the coil. That is, on the + skew side, the number of turns of the + U phase is 73% of the whole, and the number of turns of the −V phase is 27% of the whole. On the −skew side, the number of turns of the + U phase is 73% of the whole, If the number is 27% of the total, the current ratio is 27%.

  FIG. 5 is a diagram illustrating a combined current when a current ratio is 27% and a −V phase and a −W phase are added to the + U phase. As described above, the phases of the + skew side and the − skew side are shifted by 15 degrees, and the phase difference is 30 degrees in electrical angle. That is, the rotor phase difference and the current phase difference on the + skew side and the −skew side match.

  FIG. 6 is a diagram showing the magnitude and phase of torque ripple at each stage when currents are combined as shown in FIG. FIG. 7 is a diagram similarly showing the circular zero-order excitation force at each stage.

  As described above, when the phase difference between the + skew side and the −skew side is set to 30 degrees in electrical angle, the torque ripple generated in the 48th order of rotation and the circular 0th-order excitation force are shown in FIGS. 6 and 7. Thus, the + skew side and the -skew side have the same size, and the phase difference is 180 degrees. That is, both the torque ripple and the annular zero-order excitation force are canceled by the skew phase difference.

  Even when the + V phase and the + W phase are used as basic phases, an additional phase is provided based on the same idea as described above. When the basic phase is the + V phase, the additional phase on the + skew side is the −W phase, and the additional phase on the −skew side is the −U phase. When the basic phase is the + W phase, the additional phase on the + skew side is the -U phase, and the additional phase on the -skew side is the -V phase.

  As described above, the stator 10 has a divided structure corresponding to each stage of the rotor 11 having the divided skew structure, and an additional phase coil is wound around each stage of the teeth 15A and 15B, thereby energizing each stage. A phase difference is provided in the current. As a result, the torque ripple and the circular zero-order excitation force can be canceled out, and noise and vibration when the motor 1 is energized can be significantly suppressed.

The above-described embodiment can be summarized as follows.
(1) A plurality of rotors 11A and 11B are arranged adjacent to each other so as to rotate synchronously in the same rotational direction on the same rotational axis, and the permanent magnets 12 and 13 have a phase difference in the rotational direction between the adjacent rotors. Attach to each rotor. Then, coils of a plurality of phases are attached to the teeth 15 of the stator 10 arranged at positions corresponding to the rotors 11A and 11B so as to have a current phase difference in the rotation direction between the adjacent stators. As a result, not only the phases of the rotors 11A and 11B are shifted, but also the phase of the current flowing through the coil 14 of the stator 10 is shifted, and torque ripple and annular zero-order excitation force during energization can be reduced. .
(2) The coils of a plurality of phases are a basic phase and an additional phase, and the combination of the basic phase and the additional phase is different for each tooth 15. Thus, the current phase difference can be provided even in one inverter 3 by combining the currents of a plurality of phases and creating the current phase difference by changing the combination.
(3) By matching the current phase difference of the stator 10 and the phase difference of the rotor 11, the current phase relative to the magnet position is equal at each stage of the skew even during energization, and the excitation force is also equal. Thereby, the torque ripple due to the phase difference of the stage skew and the circular zero-order excitation force can be canceled out, and the excitation force reduction effect can be obtained.
(4) Since the current phase difference of the stator 10 is adjusted by the ratio of the number of turns of the basic phase and the number of turns of the additional phase, the current phase can be easily changed.
(5) The additional phase is the phase with the smallest phase difference including the phase opposite in polarity to the basic phase in each of the phase advance direction and the phase delay direction. With such a combination, the amplitude of the combined current can be increased, and as a result, the output torque of the electric motor can be further increased.
(Second Embodiment)
FIG. 8 is a configuration diagram of a system to which the second embodiment is applied. The DC current of the battery 2 is converted by the inverter 3 into U-phase, V-phase, and W-phase three-phase AC as in the first embodiment, but the first embodiment is driven by that current. The difference is that the two motors 1A and 1B are smaller than the first motor 1. That is, the two motors 1A and 1B are AC synchronous motors driven by a three-phase AC current, but are driven by one inverter 3.

  FIG. 9A is a front view of the motor unit of this embodiment, and FIG. 9B is a side view of the same. The motor 1A includes a reduction gear 20A on the rotor shaft 23, and the motor 1B similarly includes a reduction gear 20B. Both the reduction gears 20 </ b> A and 20 </ b> B mesh with a reduction gear 21 provided on the output shaft 22. That is, the motor 1 </ b> A and the motor 1 </ b> B are integral motor units that drive the output shaft 22.

  Each of the motors 1A and 1B is a distributed winding motor having 6 poles and 36 slots, and is composed of a stator and a rotor having the same shape.

  These motors 1A and 1B generate torque ripples at the rotation order that is the least common multiple of the number of poles and the number of slots, that is, at the 36th rotation. Therefore, if the torque input from the motors 1A and 1B to the output shaft 22 is in the same phase, a torque ripple occurs at the output shaft 22 in the 36th rotation.

  Although this embodiment is not a so-called step skew, it can be handled in the same manner in that there are two torque input systems with respect to the output shaft 22, and therefore, in the following description, "skew" is the same as in the first embodiment. The expression is used. The same applies to a third embodiment described later.

  In the case of a two-stage skew, a phase difference of 5 degrees (15 degrees in terms of electrical angle) may be provided in order to cancel the torque ripple generated at the 36th rotation.

  Therefore, first, the motors 1A and 1B are positioned with respect to the reduction gear 21 so that the torque transmitted from the motors 1A and 1B to the output shaft 22 via the reduction gear 21 has a phase difference of 15 degrees in electrical angle. . Here, the phase on the advance side is the + skew side, the phase on the lag side is the-skew side, the motor 1A is the + skew side, and the motor 1B is the-skew side. A coil 14 having a basic phase and an additional phase is wound to provide a phase difference in the current.

  FIG. 10A and FIG. 10B are diagrams illustrating examples of the + skew side coil 14 and the − skew side coil 14, respectively. Here, each of the basic phase + U phase, −W phase, + V phase, −U phase, + W phase, −V phase is added to the + skew motor 1A as an additional phase, −W phase, + U phase, −W phase, In the motor 1B on the -skew side, the -W phase, the + V phase, the -U phase, the + W phase, the -V phase, and the + U phase are wound together. In FIG. 10, the additional phase is displayed with parentheses, and the basic phase is displayed without parentheses.

  The number of turns of the basic phase and the additional phase is determined based on the current ratio CR of the additional phase obtained from the equation (1) as in the first embodiment. In this embodiment, about 14% of the total is an additional phase. In the present embodiment, the basic phase is wound on the outer peripheral side of the tooth 15 and the additional phase is wound on the inner peripheral side.

  By providing the additional phase as described above, the currents of the motors 1A and 1B have a phase difference of 15 electrical angles as shown in FIG. 11, and the rotor phase difference matches the current phase difference. As a result, torque ripple is canceled by the two motors 1A and 1B in the output shaft 22.

  In addition, with the arrangement of the motors 1 </ b> A and 1 </ b> B and the configuration of the coil 14 as described above, it is not possible to cancel the circular zero-order excitation force of each motor acting on the output shaft 22. However, when a plurality of small motors are used, the rigidity of the stator 10 increases as the radius decreases. As a result, the frequency of the circular zero-order resonance excited by the circular zero-order excitation force of the two motors 1A and 1B is equal to the circular zero-order excitation when one motor is used as in the first embodiment. Higher than the force frequency. If the frequency becomes higher than the normal rotation range, there is no particular problem even if the two motors 1A, 1B cannot cancel out.

  It is as follows when this embodiment mentioned above is put together.

  The plurality of rotors 11A and 11B are arranged adjacent to each other so that the rotation axes are parallel and synchronously rotate in the same rotation direction, and the permanent magnets 12 and 13 are arranged so that each rotor has a phase difference in the rotation direction. Attach to. Then, coils of a plurality of phases are attached to the teeth 15 of the stator 10 arranged at positions corresponding to the rotors 11A and 11B so as to have a current phase difference in the rotation direction between the adjacent stators. Thereby, not only the phase of the rotor 11 is shifted, but also the phase of the current flowing in the coil 14 of the stator 10 is shifted, and torque ripple at the time of energization can be reduced.

In addition, the same effects as (2)-(5) of the first embodiment can be obtained.
(Third embodiment)
FIG. 12 is a configuration diagram of a system to which the third embodiment is applied. The second embodiment is different from the second embodiment in that the motors 1A and 1B are AC synchronous motors driven by a five-phase AC current, but the other points are the same. That is, the direct current of the battery 2 is converted into a 5-phase alternating current of U phase, V phase, W phase, R phase, and S phase by the inverter 3, and the two motors 1A and 1B are driven by the current.

  FIG. 13A is a front view of the motor unit of this embodiment, and FIG. 13B is a side view of the same. The motors 1A and 1B are 6-pole 15-slot distributed winding motors, and are composed of a stator 10 and a rotor 11 having the same shape.

  These motors 1A and 1B generate torque ripples at the rotation order that is the least common multiple of the number of poles and the number of slots, that is, at the 30th rotation. Therefore, if the torque input from the motors 1A, 1B to the output shaft 22 is in the same phase, a torque ripple is generated in the output shaft 22 in the 30th rotation.

  In the case of a two-stage skew, a phase difference of 6 degrees (18 degrees in terms of electrical angle) may be provided in order to cancel the torque ripple generated in the 30th rotation. Although this embodiment is not a step skew, it can be similarly considered in that there are two torque input systems for the output shaft 22.

  Therefore, first, the motors 1A and 1B are positioned with respect to the reduction gear 21 so that the torque transmitted from the motors 1A and 1B to the output shaft 22 via the reduction gear 21 has an electrical angle of 18 degrees. . Here, the phase on the advance side is the + skew side, the phase on the lag side is the-skew side, the motor 1A is the + skew side, and the motor 1B is the-skew side. A coil 14 having a basic phase and an additional phase is wound to provide a phase difference in the current.

  FIG. 14A and FIG. 14B are diagrams illustrating examples of the + skew side and − skew side coils 14, respectively. In this embodiment, the coil 14 is attached to the slot 16. As in FIG. 10, the additional phase is shown with parentheses, and the basic phase is shown without parentheses.

  Each slot 16 is equipped with two basic phases. Specifically, it is a combination of + U phase and -R phase, + V phase and -S phase, + W phase and -U phase, + R phase and -V phase, + S phase and -W phase. 10 is the outer peripheral side, and the latter is the inner peripheral side of the stator 10.

  For each of the basic phase + U phase, + V phase, + W phase, + R phase, + S phase, -R phase, -R phase, -S phase, -U phase, -V phase, -W phase, as an additional phase, the motor 1A on the + skew side -W phase, -R phase, -S phase, -U phase, -V phase, + U phase, + V phase, + W phase, + R phase, + S phase are wound together. Similarly, in the motor 1B on the -skew side, the -R phase, -S phase, -U phase, -V phase, -W phase, + V phase, + W phase, + R phase, + S phase, + U phase are mounted together with each basic phase. Has been. That is, the stator 10 is mounted in the order of basic phase-additional phase-basic phase-additional phase from the outer peripheral side to the inner peripheral side.

  The number of turns of the basic phase and the additional phase is determined based on the current ratio CR of the additional phase obtained from the equation (1) as in the first embodiment. In this embodiment, about 26% of the total is an additional phase.

  By providing the additional phase as described above, the currents of the motors 1A and 1B have a phase difference of an electrical angle of 18 degrees as shown in FIG. 15, and the rotor phase difference matches the current phase difference. As a result, torque ripple is canceled by the two motors 1A and 1B in the output shaft 22.

  It is as follows when this embodiment mentioned above is put together.

  The plurality of rotors 11A and 11B are arranged adjacent to each other so that the rotation axes are parallel and synchronously rotate in the same rotation direction, and the permanent magnets 12 and 13 are arranged so that each rotor has a phase difference in the rotation direction. Attach to. Then, coils of a plurality of phases are attached to the slots 16 of the stator 10 arranged at positions corresponding to the rotors 11A and 11B so as to have a current phase difference in the rotation direction between the adjacent stators. Thereby, not only the phase of the rotor 11 is shifted, but also the phase of the current flowing in the coil 14 of the stator 10 is shifted, and torque ripple at the time of energization can be reduced.

  In addition, the same effects as (2)-(5) of the first embodiment can be obtained.

  The present invention is not limited to the above-described embodiments, and it goes without saying that various modifications can be made within the scope of the technical idea described in the claims.

DESCRIPTION OF SYMBOLS 1 Motor 2 Battery 3 Inverter 10 Stator 11 Rotor 12 Magnet 13 Magnet 14 Coil 15 Teeth 16 Slot 20 Reduction gear 21 Reduction gear 22 Output shaft 23 Rotor shaft

Claims (3)

In a rotary electric motor composed of a plurality of rotors having the same configuration with permanent magnets and a plurality of stators with coils attached,
The plurality of rotors are arranged adjacently so as to rotate synchronously in the same rotation direction on the same rotation axis, or the plurality of rotors are arranged adjacently so that rotation axes are parallel and synchronously rotate in the same rotation direction. Has been
The permanent magnet is attached to each rotor so as to have a phase difference in the rotation direction between the adjacent rotors,
Wherein each slot or each of the teeth of the stator which are disposed at positions corresponding to the rotor coil of the plurality of phases to have a current phase difference to the rotation direction between adjacent stator is mounted,
The coils of the plurality of phases are a basic basic phase and an additional phase different from the basic phase, and the combination of the basic phase and the additional phase is different in each slot or each tooth,
The additional phase of each slot or each tooth is a phase having the smallest phase difference including a phase opposite to the basic phase in each of the phase advance direction and the phase delay direction. Rotating electric motor characterized. The rotary electric motor according to claim 1 ,
A rotary electric motor in which a current phase difference of the stator and a phase difference of the rotor coincide. The rotary electric motor according to claim 2 , wherein
A rotary motor that adjusts the current phase difference of the stator by a ratio of the number of turns of the basic phase and the number of turns of the additional phase.