Rotating electric machine

Abstract

Reduces circulating current (zero-sequence current) in open-winding motor systems. [Solution] A permanent magnet synchronous motor 10 having an open winding structure in which the starting ends 20S, 30S, 40S and ending ends 20E, 30E, 40E of the stator windings 20, 30, 40 of each phase are open, and the stator windings 20, 30, 40 of each phase are composed of short-pitch windings with an electrical angle of 120°.

Description

Technical Field

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[0001] Relates to the winding structure of a rotating electrical machine.

Background Art

[0002] Patent Document 1 discloses an open winding motor drive system in which inverters are connected to both ends of the stator windings of each phase.

[0003] Patent Document 2 discloses a commutator motor in which a double polyphase winding is formed by overlapping non-overlapping polyphase windings in two layers and shifting them, and the permanent magnets of the corresponding field poles are configured in a composite manner according to the number of poles corresponding to the first and second ampere-turn distributions generated by the energization of the armature winding.

[0004] Patent Document 3 discloses a brushless motor including a rotor having 2P-pole permanent magnets and a stator having an armature winding with a three-phase two-pole full-pitch distributed winding.

[0005] Patent Document 4 discloses a stator coil wound around each tooth of a stator core with a 2π / 3 short-pitch winding, which is composed of two sets of three-phase connection coils, and the first three-phase connection coil and the second three-phase connection coil are each formed by Y-connecting or Δ-connecting three independent coils.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0007] In a typical three-phase Y-connection motor system, the winding ends of each phase are connected at a single point, so the 3n-th order components, which are in phase, cancel each other out and do not occur. On the other hand, in an open-winding motor system, the winding ends of each phase are not connected at a single point and are open, so the 3n-th order components generated in each phase flow independently. This results in a circulating current (zero-sequence current) that circulates within the open-winding motor system, which causes increased motor losses and heat generation. For this reason, there is a need to reduce the circulating current (zero-sequence current) in open-winding motor systems. [Means for solving the problem]

[0008] The rotating electric machine of this disclosure is a rotating electric machine having an open winding structure in which each start end and each end of the stator winding of each phase is open, and the stator winding of each phase is composed of short-pitch windings with an electrical angle of 120°. [Effects of the Invention]

[0009] As a result, the positive absolute value and the negative absolute value of the 3n-th order component generated in each phase become identical and cancel each other out. Therefore, circulating current (zero-sequence current) in open-winding motor systems is suppressed, and the increase in losses and heat generation in rotating electric machines can be reduced. [Brief explanation of the drawing]

[0010] [Figure 1] This is a diagram illustrating an open-winding motor system using a permanent magnet synchronous motor according to an embodiment. [Figure 2] This is a plan view of the stator and rotor of a permanent magnet synchronous motor according to an embodiment. [Figure 3] This is an exploded view of the stator winding of a permanent magnet synchronous motor according to an embodiment. [Figure 4] This graph shows the change in the flux linkage of the fundamental wave and the third-order component of the permanent magnet synchronous motor as a function of the electrical angle in the embodiment. [Modes for carrying out the invention]

[0011] The permanent magnet synchronous motor 10, an example of a rotating electric machine according to an embodiment, will be described below with reference to the drawings. The permanent magnet synchronous motor 10 is used in the open-winding motor system 100 shown in Figure 1. In the permanent magnet synchronous motor 10, the starting ends 20S, 30S, and 40S and the ending ends 20E, 30E, and 40E of the stator windings 20, 30, and 40 of the U, V, and W phases are open. In the open-winding motor system 100, a first inverter 51 is connected to each starting end 20S, 30S, and 40S, and a second inverter 52 is connected to each ending end 20E, 30E, and 40E. A battery 55 is connected to the first inverter 51.

[0012] As shown in Figure 2, the permanent magnet synchronous motor 10 comprises a stator 11 and a rotor 12. The stator 11 has 48 slots. Figure 2 shows six of the 48 slots, the first slots S1 to the sixth slots S6. The first slots S1 to the sixth slots S6 are wound with stator windings 20, 30, and 40 for the U-phase, V-phase, and W-phase, respectively. The stator windings 20, 30, and 40 for the U-phase, V-phase, and W-phase have an open winding structure with their respective starting ends 20S, 30S, and 40S and their respective ending ends 20E, 30E, and 40E open. Multiple permanent magnets 13 are mounted on the rotor 12.

[0013] Figure 3 is an unfolded view of the U-phase, V-phase, and W-phase stator windings 20, 30, and 40 wound in the 1st slot S1 to the 14th slot S14, out of a total of 48 slots. As shown in Figures 2 and 3, the U-phase stator winding 20 consists of a U-phase first winding 21 and a U-phase second winding 22. The U-phase first winding 21 and the U-phase second winding 22 are wound in parallel as a pair in each slot. For example, as shown in Figures 2 and 3, the U-phase first winding 21 is wound in the 1st slot S1 and the 5th slot S5, and the U-phase second winding 22 is wound in the adjacent 2nd slot S2 and the 6th slot S6. The electrical angle between the 1st slot S1 and the 5th slot S5 is 120°. Similarly, the electrical angle between the 2nd slot S2 and the 6th slot S6 is also 120°. Therefore, the winding pitch of the U-phase first winding 21 and the U-phase second winding 22 is an electrical angle of 120°. In this way, the U-phase stator winding 20 is composed of short-pitch windings with a winding pitch of an electrical angle of 120°.

[0014] Similarly, as shown in Figure 3, the V-phase and W-phase stator windings 30 and 40 are composed of the V-phase first winding 31 and the V-phase second winding 32, and the W-phase first winding 41 and the W-phase second winding 42. The winding pitch of the V-phase first winding 31 and the V-phase second winding 32, and the W-phase first winding 41 and the W-phase second winding 42 is an electrical angle of 120°. Thus, the V-phase and W-phase stator windings 30 and 40 are also composed of short-pitch windings with a winding pitch of an electrical angle of 120°.

[0015] Figure 3 shows the change in the fundamental wave and third-order flux linkage with respect to the electrical angle when the permanent magnet synchronous motor 10 is operated in the open-winding motor system 100 described with reference to Figure 1.

[0016] As shown in Figure 3, the positive absolute value and negative absolute value of the third-order component of the flux linkage generated in each phase are the same. Therefore, the third-order components cancel each other out, and the generation of circulating current (zero-sequence current) circulating within the open-winding motor system 100 can be suppressed. This suppresses the increase in losses and heat generation of the permanent magnet synchronous motor 10.

[0017] In the above description, the permanent magnet synchronous motor 10 has been described as an example of a rotating electrical machine. However, in a high-efficiency synchronous reluctance motor or an induction motor, the stator windings 20, 30, and 40 of each phase may be configured as short-pitch windings with a winding pitch of 120° electrical angle.

Explanation of Signs

[0018] 10 Permanent magnet synchronous motor, 11 Stator, 12 Rotor, 13 Permanent magnet, 20, 30, 40 Stator windings, 20E, 30E, 40E Terminals, 20S, 30S, 40S Start ends, 21 First winding of U phase, 22 Second winding of U phase, 31 First winding of V phase, 32 Second winding of V phase, 41 First winding of W phase, 42 Second winding of W phase, 51 First inverter, 52 Second inverter, 55 Battery, 100 Open winding motor system.

Claims

[Claim 1] A rotating electric machine having an open winding structure in which each start and end of the stator winding of each phase is open, The stator windings of each of the aforementioned phases are composed of short-pitch windings with a winding pitch of 120° electrical angle. A rotating electric machine characterized by the following.

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