JP2012115079A - Segment type switched reluctance motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a segment type switched reluctance motor that reduces torque ripple without necessarily requiring multi-phasing, while reducing winding resistance.SOLUTION: A segment type switched reluctance motor includes: a stator 2 that has a plurality of magnetic poles 21 and a plurality of slots 22 formed among the magnetic poles 21; a rotor 3 of a segment configuration that is arranged so as to face the stator 2 and has a plurality of magnetic segments 32; and coils 4 that are concentratedly wound around the respective magnetic poles 21 of the stator 2. Coils 4 of an identical phase are arranged in the two or more adjacent slots 22.

Description

  The present invention relates to a segment type switched reluctance motor.

  As a switched reluctance motor (hereinafter referred to as an SR motor), a variable reluctance SR motor (hereinafter referred to as a VR SR motor) is generally used as a main motor (see Patent Document 1). This VR SR motor can be characterized by the fact that the rotor is structurally robust and suitable for high-speed rotation, and that the winding resistance is reduced because the winding is concentrated winding.

  However, the VR type SR motor has a problem that the torque is small and the noise caused by the radial force is large.

  On the other hand, as an SR motor, there is an SR motor (hereinafter referred to as a segment type SR motor) in which magnetic poles of a rotor are divided into segments that are magnetically independent from each other (refer to Patent Document 2). Since this segment type SR motor has a large torque and a small radial force, the drawbacks of the VR type SR motor can be overcome.

  However, since the coil wound around the stator is fully wound, there are problems that the winding resistance becomes large and the torque ripple is large.

  Here, conventionally, in order to reduce the winding resistance, the coil end length of the motor winding is reduced by increasing the number of poles, and in order to reduce the torque ripple, for example, the phase is increased from three to four or five. Thus, it is considered that the torque pulsating in one phase is averaged by superimposing multiple phases.

  In particular, with respect to torque ripple, as shown in FIG. 7, by increasing the number of phases, a current with a phase shift in time flows and a torque with a time shift in peak is generated. Since the torque of the entire motor is the sum of these, torque ripple can be reduced by making it multiphase.

  However, although the above-described multi-phase structure remains a simple structure as a motor structure, it is necessary to increase the number of power elements (semiconductor switching elements) on the motor control circuit side, and an increase in cost remains a problem.

JP 2006-246571 A

  Accordingly, the present invention has been made to solve the above-mentioned problems all at once, and in the segment type SR motor, it is mainly intended to reduce the winding resistance and reduce the torque clip without necessarily being multiphased. This is an issue to be solved.

  That is, the switched reluctance motor according to the present invention includes a stator having a plurality of magnetic poles and a plurality of slots formed between the magnetic poles, and a segment having a plurality of magnetic segments arranged opposite to the stator. It comprises a rotor having a structure and a coil wound around each magnetic pole of the stator, and coils of the same phase are arranged in at least two adjacent slots.

  In such a case, since the coils of the same phase are arranged in at least two adjacent slots, the magnetic flux generated by the coils of the same phase is spatially dispersed. Torque ripple can be reduced. Further, since the coil wound around each magnetic pole of the stator is concentrated winding, the winding resistance can be reduced as compared with the conventional full-pitch winding.

  Regarding the torque ripple reduction of the present invention, at least two adjacent magnetic circuits are formed when one phase is excited by winding at least two adjacent slots of the same phase winding. . Since these two magnetic circuits spatially have a phase difference of electrical angle 360 / S × P / 2 [°], the torque peak also has a phase difference of electrical angle 360 / S × P / 2 [°]. Thus, the torque of the entire motor becomes the sum, and the torque ripple is reduced. In contrast to the conventional technology that increases the number of phases and flows currents that are out of phase in time to reduce torque ripple, the present invention configures a magnetic circuit that is out of phase in the same phase. Torque ripple is reduced.

  As a specific embodiment, assuming that the number of magnetic segments is P and the number of slots is S, a relationship of 120 ° <360 / S × P / 2 <210 °, 360 / S × P / 2 ≠ 180 ° It is desirable to satisfy.

  According to the present invention configured as described above, in the segmented SR motor, the winding resistance can be reduced and the torque clip can be reduced without necessarily being multiphased.

The schematic diagram which shows the structure of the segment type SR motor which concerns on this embodiment. The figure which shows the structure of the segment type SR motor of the embodiment. The figure which shows the magnetic circuit of the segment type SR motor of the embodiment. The schematic diagram of the torque waveform of the embodiment. The figure which shows the analysis result of the torque waveform of the segment type SR motor of the embodiment. The figure which shows the analysis result of the torque waveform of the conventional segment type SR motor. The schematic diagram which shows the torque ripple reduction by the conventional multiphase.

  An embodiment of the present invention will be described below with reference to the drawings.

  A segment type switched reluctance motor (segment type SR motor) 100 according to the present embodiment is an outer rotor type three-phase excitation type motor in which a rotor 3 rotates around a stator 2.

  Specifically, as shown in FIG. 1, this is arranged so as to face a stator 2 having a plurality of magnetic poles 21 and a plurality of slots 22 formed between the magnetic poles 21, and an outer peripheral surface of the stator 2. The rotor 3 has a segment structure having a plurality of magnetic segments 32 and a three-phase coil 4 wound around each magnetic pole 21 of the stator 2.

  The stator 2 is a magnetic body having a substantially cylindrical shape or a substantially columnar shape, and has a plurality of magnetic poles 21 provided at substantially equal intervals in the circumferential direction along the axial direction on the outer peripheral surface thereof. The magnetic pole 21 is a salient pole that protrudes radially outward on the outer peripheral surface of the stator 2, and has a wide end at the end facing the magnetic segment 32 to form a substantially T-shaped cross section.

  The rotor 3 has a substantially cylindrical shape having an inner peripheral surface that forms a predetermined gap with respect to the tip of the magnetic pole 21 of the stator 2. The rotor 3 is disposed coaxially with the stator 2 and rotates around the stator 2. The rotor 3 includes a rotor body 31 made of a non-magnetic material having a substantially cylindrical shape, and a plurality of magnetic bodies provided at substantially equal intervals in the circumferential direction along the axial direction on the inner peripheral surface of the rotor body 31. It has a segment 32. Each magnetic segment 32 is magnetically independent from each other.

  The coil 4 is concentratedly wound around each magnetic pole 21 of the stator 2.

  Therefore, in the segment type SR motor 100 of this embodiment, when the number of magnetic segments 32 (number of poles) is P and the number of slots 22 is S, the number of poles and the number of slots are 120 ° <360 / S × In addition to satisfying the relationship of P / 2 <210 °, 360 / S × P / 2 ≠ 180 °, the winding coils 4 of the same phase are concentratedly wound so as to be arranged in at least two adjacent slots 22. Yes.

  Hereinafter, a segment SR motor 100 having 25 poles and 30 slots satisfying the above relational expression will be described as an example. In the following, each of Example 1 and Example 2 in which the winding method of the coil 4 is different will be described. In the first embodiment, as shown in the upper part of FIG. 2, the current flowing in the coil 4 arranged in the same slot 22 is wound around the magnetic poles 21 (saliency poles) of the adjacent stator 2 by winding the same phase coil 4. This is an example in which the winding coil 4 is arranged in the adjacent slot 22 so that the orientations of the windings are the same. In the second embodiment, as shown in the lower part of FIG. 2, the magnetic poles 21 (saliency poles) of the stator 2 are formed by alternately forming thick poles and thin poles in the circumferential direction. In this example, the winding coil 4 is disposed in the slots 22 adjacent to both sides of the thick pole.

  When the number of poles is 25 and the number of slots is 30, the electrical angle between adjacent slots 22 is 360 / S × P / 2 = 150 °. When a current is passed through one phase of the segment SR motor 100, at least two adjacent magnetic circuits are formed as shown in FIG. The two magnetic circuits spatially have a phase difference of electrical angle 360 / S × P / 2 [°] = 150 °. When the rotor 3 rotates with these two magnetic circuits formed, the torque waveform becomes a waveform having a plurality of peaks having a phase difference of 360 / S × P / 2 [°] = 150 ° (FIG. 4). , Refer to FIG. 5), and the total torque is the sum thereof, so that torque ripple is reduced. Since the SR motor 100 has a symmetrical torque waveform at 180 °, torque having a phase difference of 30 ° is generated from the magnetic circuit having a phase difference of 150 ° as described above.

The torque ripple rate (= “maximum value of instantaneous torque−minimum value (T _p−p )” / “average value of instantaneous torque (T _ave )”) of the segment type SR motor 100 configured in this way is shown in Example 1. Is 0.78 and 0.62 in Example 2, which is less than half the torque ripple ratio of the conventional segment type SR motor with 20 poles and 30 slots (Fig. 6). The effect of improving noise and vibration can be confirmed.

<Effect of this embodiment>
According to the segment type switched reluctance motor 100 according to the present embodiment configured as described above, since the same-phase coil 4 is disposed in at least two adjacent slots 22, the same-phase winding is used. Since the generated magnetic flux is spatially dispersed, the torque ripple can be reduced in the segment type SR motor 100. Therefore, noise and vibration can be improved in the segment type SR motor 100. Further, since the coils 4 wound around the magnetic poles 21 of the stator 2 are concentrated windings, the winding resistance can be reduced as compared with the conventional full-pitch winding, and the winding weight to be used is reduced. Can also reduce the cost.

<Other modified embodiments>
The present invention is not limited to the above embodiment. For example, although the outer rotor type is used in the embodiment, the present invention can also be applied to an inner rotor type SR motor.

  In the embodiment, the motor is a three-phase motor, but a two-phase motor or a motor having four or more phases may be used.

  In addition, it goes without saying that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 100 ... Segment type SR motor 2 ... Stator 21 ... Magnetic pole 22 ... Slot 3 ... Rotor 31 ... Magnetic segment 4 ... Coil

Claims (2)

A stator having a plurality of magnetic poles and a plurality of slots formed between the magnetic poles, a rotor having a segment structure having a plurality of magnetic segments disposed opposite to the stator, and each of the stators A coil wound around the magnetic pole,
A switched reluctance motor, wherein coils of the same phase are arranged in at least two adjacent slots.   2. The switched reluctance motor according to claim 1, wherein when the number of magnetic segments is P and the number of slots is S, a relationship of 120 ° <360 / S × P / 2 <210 ° is satisfied.