Polyphase ac motor and winding switching system

Abstract

To improve the efficiency of a polyphase AC motor.SOLUTION: The multiphase AC motor includes a plurality of first partial windings wound around each of a plurality of teeth and a plurality of second partial windings wound around each of the plurality of teeth, and is configured to be switchable between a first connection state in which first circuits of respective phases including the first partial windings are connected to each other and a second connection state in which second circuits of respective phases including series connection circuits of the first partial windings and the second partial windings are connected to each other.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a multi-phase AC motor and a winding switching system. [Background technology]

[0002] For example, some motors mounted on electric vehicles are capable of switching between a low-speed, high-torque operating state and a high-speed, low-torque operating state by switching the connections of multiple windings.Patent Document 1 discloses a winding switching device for a three-phase AC motor in which first and second windings corresponding to U, V, and W phases are wound around each tooth provided on a fixed stator and the first and second windings of each phase are connected in series, and the device switches the connection state between a high-speed rotation winding that is a star connection of the first windings of each phase and a low-speed rotation winding that is a star connection of a DC circuit of the first and second windings of each phase. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-207919 Summary of the Invention [Problem to be solved by the invention]

[0004] In the three-phase AC motor disclosed in Patent Document 1, the first and second windings of each phase each form a slot (six slots). In the high-speed rotation winding, three of the six slots are not used, resulting in an uneven use of slots when current is applied, which causes distortion in the terminal voltage waveform and a deterioration in efficiency due to the superposition of harmonic components. [Means for solving the problem]

[0005] A polyphase AC motor according to one embodiment of the present disclosure comprises a plurality of first partial windings wound around each of a plurality of teeth and a plurality of second partial windings wound around each of the plurality of teeth, and is configured to be switchable between a first connection state in which first circuits of each phase including the first partial windings are connected to each other, and a second connection state in which second circuits of each phase including a series connection circuit of the first partial windings and the second partial windings are connected to each other. [Effects of the Invention]

[0006] According to the present disclosure, the efficiency of a polyphase AC motor can be improved. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram showing an example of the configuration of a winding switching system according to the first embodiment. [Figure 2] FIG. 2 is a cross-sectional view showing an example of the configuration of the three-phase AC motor according to the first embodiment. [Figure 3] FIG. 3 is a circuit diagram showing an example of the configuration of the winding switching device according to the first embodiment. [Figure 4A] FIG. 4A is a diagram for explaining an example of a first connection state of windings in the motor according to the first embodiment. [Figure 4B] FIG. 4B is a diagram for explaining an example of a second connection state of the windings in the motor according to the first embodiment. [Figure 5A] FIG. 5A is a diagram schematically illustrating the configuration of a comparison model for which an operational simulation was performed. [Figure 5B] FIG. 5B is a diagram schematically illustrating the configuration of the target model for which the operation simulation was performed. [Figure 6] FIG. 6 is a graph showing the evaluation results of the current-torque characteristics of the motor according to the first embodiment. [Figure 7] FIG. 7 is a graph showing evaluation results of iron loss in the motor according to the first embodiment. [Figure 8] FIG. 8 is a cross-sectional view showing an example of the configuration of a three-phase AC motor according to the second embodiment. [Figure 9] FIG. 9 is a diagram showing an example of the connection relationship of the U-phase winding in the motor according to the second embodiment. [Figure 10A] FIG. 10A is a diagram for explaining an example of a first connection state of windings in a motor according to a second embodiment. [Figure 10B] FIG. 10B is a diagram for explaining an example of a second connection state of the windings in the motor according to the second embodiment. [Figure 11] FIG. 11 is a graph showing an example of the characteristics of the rotation speed and output torque of the motor in each of a plurality of connection states. [Figure 12A] FIG. 12A is a diagram illustrating a first modified example of the connection state of windings in the motor according to the second embodiment. [Figure 12B] FIG. 12B is a diagram illustrating a second variation of the connection state of windings in the motor according to the second embodiment. [Figure 12C] FIG. 12C is a diagram illustrating a third variation of the connection state of the windings in the motor according to the second embodiment. [Figure 12D] FIG. 12D is a diagram for explaining a fourth variation of the connection state of windings in the motor according to the second embodiment. [Figure 12E] FIG. 12E is a diagram for explaining a fifth variation of the connection state of windings in the motor according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] <Summary of Embodiments of the Present Disclosure> The following provides an outline of embodiments of the present disclosure.

[0009] (1) A polyphase AC motor according to this embodiment includes a plurality of first partial windings wound around a plurality of teeth, respectively, and a plurality of second partial windings wound around the plurality of teeth, and is configured to be switchable between a first connection state in which first circuits for each phase, including the first partial windings, are connected to each other, and a second connection state in which second circuits for each phase, including series-connected circuits of the first partial windings and the second partial windings, are connected to each other. Since the windings in the slots are divided into the first partial windings and the second partial windings, the first connection state can be an intermediate connection state in which the windings in one slot are partially used. This reduces bias in the slots used during current application, thereby improving the efficiency of the polyphase AC motor.

[0010] (2) In the above (1), a first-phase slot corresponding to a first phase and including the first partial winding and the second partial winding wound around the same tooth may be adjacent to a second-phase slot corresponding to a second phase and including the first partial winding and the second partial winding wound around the same tooth, and the second-phase slot may be adjacent to a third-phase slot corresponding to a third phase and including the first partial winding and the second partial winding wound around the same tooth. In this manner, in a polyphase AC motor configured such that slots of the same phase are dispersed, the number of unused slots can be reduced, thereby reducing the unevenness of the used slots when current is applied and improving the efficiency of the polyphase AC motor.

[0011] (3) In the above (1), a plurality of first-phase slots corresponding to a first phase, each including the first partial winding and the second partial winding wound around the same tooth, may be arranged adjacently, a plurality of second-phase slots corresponding to a second phase, each including the first partial winding and the second partial winding wound around the same tooth, may be arranged adjacently, and a plurality of third-phase slots corresponding to a third phase, each including the first partial winding and the second partial winding wound around the same tooth, may be arranged adjacently. In this multi-phase AC motor having slots of the same phase arranged in a concentrated arrangement, at least three states can be selected for one slot: a state in which only the first partial winding is used, a state in which both the first partial winding and the second partial winding are used, and a state in which neither the first partial winding nor the second partial winding is used. This increases the number of combinations of usable winding connections, allowing a connection state suitable for the application to be selected.

[0012] (4) In the above (3), the number of teeth may be odd. This increases the number of usable winding connection combinations in a multi-slot AC motor with an odd number of slots, allowing selection of a connection state suitable for the application.

[0013] (5) In any one of (1) to (4) above, the first circuit corresponding to a first phase may include a first series connection circuit in which the first partial winding wound around a first tooth corresponding to the first phase, the first partial winding wound around a second tooth corresponding to the first phase, and the second partial winding wound around the second tooth are connected in series. This allows the first connection state to be an intermediate connection state in which three first partial windings are connected in series.

[0014] (6) In any one of (1) to (4) above, the first circuit corresponding to a first phase may include a second series-connected circuit in which the first partial winding wound around a first tooth corresponding to the first phase, the first partial winding wound around a second tooth corresponding to the first phase, and the first partial winding wound around a third tooth corresponding to the first phase are connected in series. This allows the first connection state to be an intermediate connection state in which three first partial windings are connected in series.

[0015] (7) In the above (5) or (6), the second circuit corresponding to the first phase may include a third series-connected circuit in which the first partial winding wound around the first tooth, the second partial winding wound around the first tooth, the first partial winding wound around the second tooth, and the second partial winding wound around the second tooth are connected in series, thereby making it possible to set the second connection state to a state in which the windings in two slots are connected in series.

[0016] (8) In the above (5) or (6), the second circuit corresponding to the first phase may include a fourth series-connected circuit in which the first partial winding wound on the first tooth, the second partial winding wound on the first tooth, the first partial winding wound on the second tooth, the second partial winding wound on the second tooth, the first partial winding wound on the third tooth corresponding to the first phase, and the second partial winding wound on the third tooth are connected in series. This allows the second connection state to be a state in which windings in three slots are connected in series.

[0017] (9) In any one of the above (1) to (8), the polyphase AC motor may be configured to be switchable among the first connection state, the second connection state, and a third connection state in which the first circuit and a third circuit of each phase different from the second circuit are connected to each other. This allows the connection state of the windings to be switched among various connection states including the first connection state, which is an intermediate connection state.

[0018] (10) A winding switching system according to this embodiment includes a polyphase AC motor capable of switching the connection state of a plurality of windings between a first connection state and a second connection state, a power converter that converts power output from a power source into AC power and supplies the AC power to the AC motor, and a winding switching device that switches the connection state of the plurality of windings. The polyphase AC motor includes a plurality of first partial windings wound around a plurality of teeth and a plurality of second partial windings wound around the plurality of teeth. The first connection state is a connection state in which first circuits for each phase, including the first partial windings, are connected to each other, and the second connection state is a connection state in which second circuits for each phase, including a series-connected circuit of the first partial windings and the second partial windings, are connected to each other. Since the windings in each slot are divided into the first partial windings and the second partial windings, the first connection state can be an intermediate connection state in which a winding in one slot is partially used. This reduces bias in the slots used during current application, improving the efficiency of the polyphase AC motor.

[0019] The present disclosure can be realized not only as a polyphase AC motor having the above-described characteristic configuration, and a winding switching system including a polyphase AC motor, but also as a control device that switches the winding connection state of a polyphase AC motor, a control method that switches the winding connection state of a polyphase AC motor, a control program for switching the winding connection state of a polyphase AC motor, and a semiconductor integrated circuit that realizes part or all of the control device.

[0020] <Details of the embodiment of the present disclosure> DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, detailed descriptions of embodiments of the present invention will be given with reference to the accompanying drawings. At least some of the embodiments described below may be combined in any desired manner.

[0021] [1. First embodiment] [1-1. Winding switching system] FIG. 1 is a diagram showing an example of the configuration of a winding switching system according to the first embodiment.

[0022] The winding switching system 10 is mounted on a vehicle (hereinafter referred to as an "electric vehicle") that is propelled by a motor, such as an electric vehicle or a plug-in hybrid vehicle. The winding switching system 10 includes a motor 20, a power converter 30, a battery 40, a control device 50, and a winding switching device 100.

[0023] The motor 20 is a driving motor that generates propulsion power for the electric vehicle. The motor 20 is a three-phase AC motor that is driven by three-phase AC power. An example of the motor 20 is a permanent magnet synchronous motor.

[0024] The battery 40 is a battery for supplying power to drive the motor 20. The battery 40 is a secondary battery, for example, a lithium ion battery.

[0025] The power converter 30 is an inverter that converts DC power supplied from the battery 40 into three-phase AC power. The power converter 30 may have a function of converting the three-phase AC power output when the motor 20 functions as a generator into DC power and charging the battery 40.

[0026] The power converter 30 includes U-phase, V-phase, and W-phase legs. The U-phase leg includes switches 31u and 32u, the V-phase leg includes switches 31v and 32v, and the W-phase leg includes switches 31w and 32w. The switches 31u, 32u, 31v, 32v, 31w, and 32w perform switching to convert DC power into three-phase AC power. The switches 31u, 32u, 31v, 32v, 31w, and 32w are, for example, insulated gate bipolar transistors (IGBTs) or power metal oxide semiconductor field-effect transistors (MOSFETs).

[0027] A power line 35u corresponding to the U phase extends from the U-phase leg, a power line 35v corresponding to the V phase extends from the V-phase leg, and a power line 35w corresponding to the W phase extends from the W-phase leg. In the power converter 30, a current sensor 33u is provided on the power line 35u, a current sensor 33v is provided on the power line 35v, and a current sensor 33w is provided on the power line 35w. The current sensor 33u detects the current value of the U-phase current Iu. The current sensor 33v detects the current value of the V-phase current Iv. The current sensor 33w detects the current value of the W-phase current Iw. The current sensors 33u, 33v, and 33w can detect the current values ​​of the currents Iu, Iv, and Iw flowing through the power lines 35u, 35v, and 35w, including the DC and AC components. The current sensors 33u, 33v, and 33w are, for example, DCCTs (direct current transformers) or shunt resistors.

[0028] The winding switching device 100 is disposed between the motor 20 and the power converter 30. However, the position of the winding switching device 100 is not limited to between the motor 20 and the power converter 30. The power converter 30 and the winding switching device 100 are connected by power lines 35u, 35v, and 35w, and the winding switching device 100 and the motor 20 are connected by multiple power lines 25. The winding switching device 100 switches the connection state of multiple windings of the motor 20. The configuration of the winding switching device 100 will be described later. Three-phase AC currents Iu, Iv, and Iw output from the power converter 30 are supplied to the motor 20 via the winding switching device 100.

[0029] The control device 50 controls the power converter 30 and the winding switching device 100. Specifically, signal lines extend from the control device 50 to each of the switches 31u, 32u, 31v, 32v, 31w, and 32w, and the control device 50 controls the on / off timing of the switches 31u, 32u, 31v, 32v, 31w, and 32w. A signal line extends from the control device 50 to the winding switching device 100, and the control device 50 outputs a switching command signal to the winding switching device 100 to command the switching of the connection state of the windings.

[0030] [1-2. Three-phase AC motor configuration] Fig. 2 is a cross-sectional view showing an example of the configuration of the three-phase AC motor according to the first embodiment, showing a cross section perpendicular to the central axis.

[0031] The motor 20 includes a stator 210 and a rotor 220 .

[0032] The stator 210 is made of a soft magnetic material and includes a cylindrical yoke 210Y and a plurality of teeth 210Tu1, 210Tv1, 210Tw1, 210Tu2, 210Tv2, 210Tw2, 210Tu3, 210Tv3, 210Tw3, 210Tu4, 210Tv4, and 210Tw4 arranged on the inner periphery of the yoke. Hereinafter, the teeth 210Tu1, 210Tv1, 210Tw1, 210Tu2, 210Tv2, 210Tw2, 210Tu3, 210Tv3, 210Tw3, 210Tu4, 210Tv4, and 210Tw4 will be collectively referred to as "teeth 210T."

[0033] Each of the plurality of teeth 210T is a protrusion extending from the inner peripheral surface of the yoke 210Y toward the center. The plurality of teeth 210T are arranged at equal intervals in the circumferential direction around the central axis O of the motor 20.

[0034] Each of the multiple teeth 210T corresponds to one of the U-phase, V-phase, and W-phase. A winding is wound around each tooth 210T. The winding wound around one tooth forms a slot. In other words, the number of slots is the same as the number of teeth. In the example shown in FIG. 2, the number of slots is 12.

[0035] In the motor 20 according to the present disclosure, the winding is divided in each slot. That is, a first partial winding and a second partial winding are wound around each tooth 210T. The first partial winding and the second partial winding wound around the tooth 210T corresponding to the U phase correspond to the U phase. The first partial winding and the second partial winding wound around the tooth 210T corresponding to the V phase correspond to the V phase. The first partial winding and the second partial winding wound around the tooth 210T corresponding to the W phase correspond to the W phase.

[0036] Specifically, the first partial windings 21u1, 21u2, 21u3, and 21u4 and the second partial windings 22u1, 22u2, 22u3, and 22u4 corresponding to the U phase are wound around the teeth 210Tu1, 210Tu2, 210Tu3, and 210Tu4 corresponding to the U phase, respectively. Here, elements having the same reference numerals "u1," "u2," "u3," and "u4" correspond to one another. That is, for example, the first partial winding 21u1 and the second partial winding 22u1 are wound around the tooth 210Tu1. The first partial winding 21u2 and the second partial winding 22u2 are wound around the tooth 210Tu2. The first partial winding 21u3 and the second partial winding 22u3 are wound around the tooth 210Tu3. The first partial winding 21u4 and the second partial winding 22u4 are wound around the tooth 210Tu4. That is, the U-phase slot Su1 includes the first partial winding 21u1 and the second partial winding 22u1. The U-phase slot Su2 includes the first partial winding 21u2 and the second partial winding 22u2. The U-phase slot Su3 includes the first partial winding 21u3 and the second partial winding 22u3. The U-phase slot Su4 includes the first partial winding 21u4 and the second partial winding 22u4.

[0037] Similarly, the first partial windings 21v1, 21v2, 21v3, 21v4 and the second partial windings 22v1, 22v2, 22v3, 22v4 corresponding to the V phase are wound around the teeth 210Tv1, 210Tv2, 210Tv3, 210Tv4 corresponding to the V phase, respectively. That is, the V-phase slot Sv1 includes the first partial winding 21v1 and the second partial winding 22v1. The V-phase slot Sv2 includes the first partial winding 21v2 and the second partial winding 22v2. The V-phase slot Sv3 includes the first partial winding 21v3 and the second partial winding 22v3. The V-phase slot Sv4 includes the first partial winding 21v4 and the second partial winding 22v4. The first partial windings 21w1, 21w2, 21w3, 21w4 and the second partial windings 22w1, 22w2, 22w3, 22w4 corresponding to the W phase are wound around the teeth 210Tw1, 210Tw2, 210Tw3, 210Tw4 corresponding to the W phase, respectively. That is, the W-phase slot Sw1 includes the first partial winding 21w1 and the second partial winding 22w1. The W-phase slot Sw2 includes the first partial winding 21w2 and the second partial winding 22w2. The W-phase slot Sw3 includes the first partial winding 21w3 and the second partial winding 22w3. The W-phase slot Sw4 includes the first partial winding 21w4 and the second partial winding 22w4.

[0038] In the motor 20 according to the first embodiment, the four slots Su1, Su2, Su3, and Su4 of the U phase are arranged in a dispersed manner. The four slots Sv1, Sv2, Sv3, and Sv4 of the V phase are arranged in a dispersed manner, and the four slots Sw1, Sw2, Sw3, and Sw4 of the W phase are arranged in a dispersed manner. More specifically, the slots Su1, Sv1, Sw1, Su2, Sv2, Sw2, Su3, Sv3, Sw3, Su4, Sv4, and Sw4 are arranged in this order in the counterclockwise direction in FIG. 2 .

[0039] Therefore, the slot Su1 corresponding to the U phase and the slot Sv1 corresponding to the V phase are adjacent to each other, and the slot Sv1 corresponding to the V phase and the slot Sw1 corresponding to the W phase are adjacent to each other. The slot Sw1 corresponding to the W phase and the slot Su2 corresponding to the U phase are adjacent to each other. In this way, adjacent slots are in different phases. More specifically, the slots are arranged in a counterclockwise direction in the figure, circulating in the order of U phase, V phase, and W phase.

[0040] The rotor 220 includes a plurality of permanent magnets 220M. The plurality of permanent magnets 220M are arranged in an annular shape in the circumferential direction of the central axis O. More specifically, each permanent magnet 220M has an elongated plate shape. Adjacent pairs of permanent magnets 220M are arranged in a V-shape when viewed in the direction of the central axis O, and each pair of permanent magnets 220M is arranged in an annular shape so that the tip of the V faces the central axis O. In other words, each permanent magnet 220M is inclined with respect to the radial direction so that a first end of the permanent magnet 220M is away from the central axis O and a second end is closer to the central axis O.

[0041] For example, a first end of the permanent magnet 220M that is farther from the central axis O is an S pole, and a second end that is closer to the central axis O is an N pole. In other words, the ends of adjacent permanent magnets 220M that are close to each other have the same polarity. The first ends of a pair of adjacent permanent magnets 220M whose first ends are close to each other form an S pole, and the second ends of a pair of adjacent permanent magnets 220M whose second ends are close to each other form an N pole.

[0042] The number of permanent magnets 220M shown in FIG. 2 is 16. Therefore, the 16 permanent magnets 220M form eight south poles and eight north poles. That is, the number of poles of the motor 20 shown in FIG. 2 is eight. Therefore, the motor 20 is an eight-pole, 12-slot three-phase AC permanent magnet synchronous motor.

[0043] [1-3. Configuration of winding switching device] 3 is a circuit diagram showing an example of the configuration of the winding switching device according to the first embodiment. As described above, the first partial windings 21u1, 21u2, 21u3, and 21u4 and the second partial windings 22u1, 22u2, 22u3, and 22u4 correspond to the U-phase, the first partial windings 21v1, 21v2, 21v3, and 21v4 and the second partial windings 22v1, 22v2, 22v3, and 22v4 correspond to the V-phase, and the first partial windings 21w1, 21w2, 21w3, and 21w4 and the second partial windings 22w1, 22w2, 22w3, and 22w4 correspond to the W-phase. However, the number of partial windings in each slot is not limited to two and may be three or more.

[0044] The winding switching device 100 switches the connection states of the first partial windings 21u1, 21u2, 21u3, 21u4, 21v1, 21v2, 21v3, 21v4, 21w1, 21w2, 21w3, and 21w4 and the second partial windings 22u1, 22u2, 22u3, 22u4, 22v1, 22v2, 22v3, 22v4, 22w1, 22w2, 22w3, and 22w4 for each phase between a first connection state and a second connection state. More specifically, the winding switching device 100 switches the number of series connections of the first partial windings 21u1, 21u2, 21u3, 21u4, 21v1, 21v2, 21v3, 21v4, 21w1, 21w2, 21w3, and 21w4 and the second partial windings 22u1, 22u2, 22u3, 22u4, 22v1, 22v2, 22v3, 22v4, 22w1, 22w2, 22w3, and 22w4 for each phase. The U phase will be described as a representative example. For example, the first connection state is a state in which the first partial windings 21u1, 21u2, 21u3, and 21u4 are connected in series. In the second connection state, the first partial windings 21u1, 21u2, 21u3, and 21u4 and the second partial windings 22u1, 22u2, 22u3, and 22u4 are connected in series. The first connection state is a high-speed connection state in which the rotation speed of the motor 20 is high. The second connection state is a high-torque connection state in which the output torque of the motor 20 is high. The same applies to the full connection state and partial connection state in the V-phase and W-phase.

[0045] Hereinafter, the first partial windings 21u1, 21u2, 21u3, 21u4, 21v1, 21v2, 21v3, 21v4, 21w1, 21w2, 21w3, and 21w4 will be collectively referred to as the "first partial windings 21," and the second partial windings 22u1, 22u2, 22u3, 22u4, 22v1, 22v2, 22v3, 22v4, 22w1, 22w2, 22w3, and 22w4 will be collectively referred to as the "second partial winding 22."

[0046] The winding switching device 100 includes current sensors 131u, 131v, and 131w, zero-cross detection circuits 102u, 102v, and 102w, control circuits 103u, 103v, and 103w, and switching circuits 140u, 140v, and 140w.

[0047] The zero-crossing detection circuits 102u, 102v, and 102w detect zero-crossing points of the measurements of the current sensors 131u, 131v, and 131w. In a more specific example, the zero-crossing detection circuits 102u, 102v, and 102w compare the output voltages from the current sensors 131u, 131v, and 131w with zero voltage and detect the time points when the output voltages from the current sensors 131u, 131v, and 131w match a reference voltage as the zero-crossing points. The zero voltage is an example of a reference voltage. The reference voltage is a voltage corresponding to the output voltages of the current sensors 131u, 131v, and 131w when the currents flowing through the first partial winding 21 and the second partial winding 22 become zero, and is not limited to zero voltage.

[0048] The switching circuits 140u, 140v, and 140w switch the connection states of the first partial winding 21 and the second partial winding 22 between a first connection state and a second connection state at the timing when the zero-cross detection circuits 102u, 102v, and 102w detect a zero-cross point.

[0049] The following describes the connection relationship between the winding switching device 100, the power line 35u, and the motor 20 for the U phase. The same applies to the V and W phases, so the description will be omitted.

[0050] The power line 35u is connected to a first end of the first winding circuit Cu1, which is made up of first partial windings 21u1, 21u2, 21u3, and 21u4 connected in series. A second end of the first winding circuit Cu1 and a first end of the second winding circuit Cu2, which is made up of second partial windings 22u1, 22u2, 22u3, and 22u4 connected in series, are connected to each other, and a power line 241u extends from the connection point (the midpoint between the first winding circuit Cu1 and the second winding circuit Cu2). The power line 241u branches into power lines 242u and 243w. A power line 251u extends from a second end of the second winding circuit Cu2. The power line 251u branches into power lines 252u and 253w.

[0051] The power line 35v is connected to a first end of the first winding circuit Cv1, which is made up of first partial windings 21v1, 21v2, 21v3, and 21v4 connected in series. A second end of the first winding circuit Cv1 and a first end of the second winding circuit Cv2, which is made up of second partial windings 22v1, 22v2, 22v3, and 22v4 connected in series, are connected to each other, and a power line 241v extends from this connection point (the midpoint between the first winding circuit Cv1 and the second winding circuit Cv2). The power line 241v branches into power lines 242v and 243u. A power line 251v extends from a second end of the second winding circuit Cv2. The power line 251v branches into power lines 252v and 253u.

[0052] The power line 35w is connected to a first end of the first winding circuit Cw1, which is made up of first partial windings 21w1, 21w2, 21w3, and 21w4 connected in series. A second end of the first winding circuit Cw1 and a first end of the second winding circuit Cw2, which is made up of second partial windings 22w1, 22w2, 22w3, and 22w4 connected in series, are connected to each other, and a power line 241w extends from the connection point (the midpoint between the first winding circuit Cw1 and the second winding circuit Cw2). The power line 241w branches into power lines 242w and 243v. A power line 251w extends from a second end of the second winding circuit Cw2. The power line 251w branches into power lines 252w and 253v.

[0053] The switching circuit 140u includes semiconductor relays 141u and 142u. The switching circuit 140v includes semiconductor relays 141v and 142v. The switching circuit 140w includes semiconductor relays 141w and 142w. The semiconductor relays 141u, 142u, 141v, 142v, 141w, and 142w are, for example, IGBTs or power MOSFETs.

[0054] In the switching circuit 140u, a first terminal of a semiconductor relay 141u is connected to a power line 242u, and a second terminal is connected to a power line 243u. A first terminal of a semiconductor relay 142u is connected to a power line 252u, and a second terminal is connected to a power line 253u. The connection relationship between the switching circuits 140v and 140w is the same as that of the switching circuit 140u, so a description thereof will be omitted.

[0055] When the semiconductor relay 141u is in the off state and the semiconductor relay 142u is in the on state, the U-phase first winding circuit Cu1 and the U-phase second winding circuit Cu2 are connected in series. That is, in this case, the first partial windings 21u1, 21u2, 21u3, and 21u4 and the second partial windings 22u1, 22u2, 22u3, and 22u4 are all connected in series, resulting in a second connection state. When the semiconductor relay 141u is in the on state and the semiconductor relay 142u is in the off state, the first partial windings 21u1, 21u2, 21u3, and 21u4 of the U-phase first partial windings 21u1, 21u2, 21u3, and 21u4 and the second partial windings 22u1, 22u2, 22u3, and 22u4 are all connected in series, resulting in a first connection state. The same applies to the V-phase and W-phase. In this example, the first winding circuit Cu1 corresponds to the "first circuit" of the U phase, and the circuit in which the first winding circuit Cu1 and the second winding circuit Cu2 are connected in series corresponds to the "second circuit" of the U phase. The first connection state is a state in which the first winding circuits Cu1, Cv1, and Cw1 are connected to one another, and the second connection state is a state in which the series-connected circuit of the first winding circuit Cu1 and the second winding circuit Cu2, the series-connected circuit of the first winding circuit Cv1 and the second winding circuit Cv2, and the series-connected circuit of the first winding circuit Cw1 and the second winding circuit Cw2 are connected to one another.

[0056] The power line 35u is drawn into the winding switching device 100. A current sensor 131u is attached to the power line 35u. The current sensor 131u detects the U-phase current flowing through the power line 35u. The current sensor 131u is, for example, an ACCT that detects only the AC component of the current. A signal line extending from the current sensor 131u is connected to the zero-cross detection circuit 102u. A signal line that transmits an output signal of the zero-cross detection circuit 102u (hereinafter referred to as the "zero-cross detection signal") extends from the zero-cross detection circuit 102u to the control circuit 103u. Furthermore, a signal line extending from the control device 50 is connected to the control circuit 103u. The same applies to the V-phase and W-phase.

[0057] The zero-crossing detection circuit 102u detects zero-crossing points of the winding current flowing through the power line 35u measured by the current sensor 131u. The zero-crossing detection circuit 102u is a comparator. For example, the inverting input of the comparator is set to a zero reference voltage, and the output signal of the current sensor 131u is applied to the non-inverting input. As a result, when the AC signal output from the current sensor 131u crosses the zero reference voltage (the zero-crossing point), the output of the comparator changes from low to high.

[0058] The control circuit 103u receives a switching command signal output from the control device 50 and a zero-cross detection signal output from the zero-cross detection circuit 102u. The control circuit 103u controls the semiconductor relays 141u and 142u at the timing when the switching command signal and the zero-cross detection signal are input. For example, when the semiconductor relay 141u is in the OFF state and the semiconductor relay 142u is in the ON state, the control device 50 switches the semiconductor relay 141u to the ON state and the semiconductor relay 142u to the OFF state at the timing when the switching command signal and the zero-cross detection signal are input to the control device 50. This switches the winding connection state of the motor 20 from the second connection state to the first connection state. When the semiconductor relay 141u is in the ON state and the semiconductor relay 142u is in the OFF state, the control device 50 switches the semiconductor relay 141u to the OFF state and switches the semiconductor relay 142u to the ON state at the timing when a switching command signal and a zero-cross detection signal are input to the control device 50. As a result, the winding connection state of the motor 20 switches from the first connection state to the second connection state.

[0059] The control circuit 103u is configured, for example, by an RS flip-flop. The control circuit 103u may be configured by a D flip-flop, a processor, an ASIC (Application Specific Integrated Circuit), or an FPGA (Field Programmable Gate Array). The same applies to the control circuits 103v and 103w.

[0060] The control device 50 is configured with, for example, a processor, a memory, an interface, etc., and controls the winding switching device 100 by executing a control program with the processor. Note that at least a part of the control device 50 may be configured with an ASIC or an FPGA.

[0061] [1-4. Winding connection status] Fig. 4A is a diagram illustrating an example of a first connection state of the windings in the motor according to the first embodiment, and Fig. 4B is a diagram illustrating an example of a second connection state of the windings in the motor according to the first embodiment. In Fig. 4A and Fig. 4B, the windings surrounded by dashed lines are windings connected to a power supply (i.e., windings used to drive motor 20A). The windings not surrounded by dashed lines are windings not connected to a power supply (i.e., windings not used to drive motor 20A).

[0062] 4A, in the first connection state of this example, all of the first partial windings 21u1, 21v1, 21w1, 21u2, 21v2, 21w2, 21u3, 21v3, 21w3, 21u4, 21v4, and 21w4 in the slots Su1, Sv1, Sw1, Su2, Sv2, Sw2, Su3, Sv3, Sw3, Su4, Sv4, and Sw4, respectively, are used. Therefore, there is no bias in the slots used, and the motor 20 can be driven efficiently.

[0063] 4B, in the second connection state of this example, all of the first partial windings 21u1, 21v1, 21w1, 21u2, 21v2, 21w2, 21u3, 21v3, 21w3, 21u4, 21v4, and 21w4 and the second partial windings 22u1, 22v1, 22w1, 22u2, 22v2, 22w2, 22u3, 22v3, 22w3, 22u4, 22v4, and 22w4 in the slots Su1, Sv1, Sw1, Su2, Sv2, Sw2, Su3, Sv3, Sw3, Su4, Sv4, and Sw4 are used. Therefore, even in the second connection state, there is no bias in the slots used, and the motor 20 can be driven efficiently.

[0064] [1-5.Evaluation] The inventors performed an operational simulation of the motor 20 according to the first embodiment and evaluated the performance of the motor 20.

[0065] In the evaluation, a model of an 8-pole, 12-slot three-phase AC permanent magnet synchronous motor (hereinafter also referred to as the "comparison model") was created, and an operational simulation of the comparison model was performed in a state in which the windings of two opposing slots (i.e., 180° apart) of each phase were connected in series. Furthermore, a model of motor 20 according to the above-described first embodiment (hereinafter also referred to as the "target model") was created, and an operational simulation of the target model in the first connection state was performed.

[0066] FIG. 5A is a diagram schematically illustrating the configuration of the comparative model, and FIG. 5B is a diagram schematically illustrating the configuration of the target model. The comparative model and target model each have 8 poles, 12 slots, a winding current of 34 Arms, a motor drive frequency of 100 Hz, and 47 turns per slot. In FIGS. 5A and 5B, circles represent slots. In FIG. 5B, the two semicircles into which the circle is divided represent the divided slots. The upper semicircle of each circle in FIG. 5B represents the "first partial winding," and the lower semicircle of each circle represents the "second partial winding."

[0067] In Figure 5A, the driven slots are indicated by hatching, and in Figure 5B, the driven divided slots are indicated by hatching. As shown in Figure 5A, an operational simulation of the comparative model was performed with the windings in slots U1 and U3 connected in series, the windings in slots V2 and V4 connected in series, and the windings in slots W1 and W3 connected in series. In the operational simulation of the comparative model, slots U2, U4, V1, V3, W2, and W4 were not used.

[0068] 5B, the operation simulation of the target model was performed in a first connection state in which the first partial windings of the slots U1, U2, U3, and U4 were connected in series, the first partial windings of the slots V1, V2, V3, and V4 were connected in series, and the first partial windings of the slots W1, W2, W3, and W4 were connected in series. In the operation simulation of the target model, the second partial windings of the slots U1, U2, U3, U4, V1, V2, V3, V4, W1, W2, W3, and W4 were not used.

[0069] The number of turns in the first partial winding of each slot in the target model is 47 / 2, and the number of turns in the second partial winding of each slot is 47 / 2. In other words, the number of turns in each of the first partial winding and the second partial winding is half the number of turns in one slot. Therefore, the total number of turns in the windings connected in the operational simulation of the comparison model is the same as the total number of turns in the windings connected in the operational simulation of the target model.

[0070] Fig. 6 is a graph showing the evaluation results of the current-torque characteristics of the motor according to Embodiment 1. In Fig. 6, the vertical axis represents the average torque output by motor 20, and the horizontal axis represents the current applied to the windings.

[0071] The dashed line graph in Figure 6 shows the simulation results for the comparative model. In the comparative model, the average torque increases roughly linearly with respect to the current value when the current value (peak value) is less than 30 A, but the ratio of the average torque to the current value decreases when the current value is 30 A or more.

[0072] The solid line graph in Figure 6 shows the simulation results for the target model. In the target model, the average torque increases roughly linearly with respect to the current value over the entire range of current values ​​(peak values), and no decrease in the ratio of average torque to current value is observed. This indicates that the current-torque characteristics improve as the bias in the slots used decreases.

[0073] FIG. 7 is a graph showing evaluation results of iron loss in the motor according to the first embodiment. In FIG. 7, the bar graph on the right shows simulation results of iron loss in the comparison model, and the bar graph on the left shows simulation results of iron loss in the target model. In FIG. 7, "St york_hysteresis loss" means "hysteresis loss of the stator yoke," and "St york_eddy loss" means "eddy current loss of the stator yoke." "St teeth_hysteresis loss" means "hysteresis loss of the stator teeth," and "St teeth_eddy loss" means "eddy current loss of the stator teeth." "Rt_hysteresis loss" means "hysteresis loss of the rotor," and "Rt_eddy loss" means "eddy current loss of the rotor."

[0074] As shown in Figure 7, the target model has lower stator yoke hysteresis loss, stator yoke eddy current loss, rotor hysteresis loss, and rotor eddy current loss than the comparison model. In particular, the rotor eddy current loss is significantly improved, at 1.0 W for the target model, compared to 4.8 W for the comparison model. The total iron loss for the comparison model is 25.2 W, while the total iron loss for the target model is 20.7 W. This shows that the target model has significantly improved iron loss compared to the comparison model.

[0075] [2. Second Embodiment] [2-1. Three-phase AC motor configuration] FIG. 8 is a cross-sectional view showing an example of the configuration of a three-phase AC motor according to the second embodiment.

[0076] A motor 20A according to the second embodiment is an eight-pole, nine-slot, three-phase AC permanent magnet synchronous motor.

[0077] The motor 20A includes a stator 210A and a rotor 220A.

[0078] The stator 210A is made of a soft magnetic material and includes a cylindrical yoke 210YA, and a plurality of teeth 210Tu1A, 210Tu2A, 210Tu3A, 210Tv1A, 210Tv2A, 210Tv3A, 210Tw1A, 210Tw2A, and 210Tw3A arranged on the inner periphery of the yoke.

[0079] The first partial windings 21u1A, 21u2A, 21u3A and the second partial windings 22u1A, 22u2A, 22u3A corresponding to the U phase are wound around the teeth 210Tu1A, 210Tu2A, 210Tu3A corresponding to the U phase, respectively. Here, elements having the common reference numerals "u1A," "u2A," and "u3A" correspond to one another. The U-phase slot Su1A includes the first partial winding 21u1A and the second partial winding 22u1A. The U-phase slot Su2A includes the first partial winding 21u2A and the second partial winding 22u2A. The U-phase slot Su3A includes the first partial winding 21u3A and the second partial winding 22u3A.

[0080] Similarly, first partial windings 21v1A, 21v2A, 21v3A and second partial windings 22v1A, 22v2A, 22v3A corresponding to the V phase are wound around the teeth 210Tv1A, 210Tv2A, 210Tv3A corresponding to the V phase, respectively. That is, the V-phase slot Sv1A includes the first partial winding 21v1A and the second partial winding 22v1A. The V-phase slot Sv2A includes the first partial winding 21v2A and the second partial winding 22v2A. The V-phase slot Sv3A includes the first partial winding 21v3A and the second partial winding 22v3A. The first partial windings 21w1A, 21w2A, 21w3A and the second partial windings 22w1A, 22w2A, 22w3A corresponding to the W phase are wound around the teeth 210Tw1A, 210Tw2A, 210Tw3A corresponding to the W phase, respectively. That is, the W-phase slot Sw1A includes the first partial winding 21w1A and the second partial winding 22w1A. The W-phase slot Sw2A includes the first partial winding 21w2A and the second partial winding 22w2A. The W-phase slot Sw3A includes the first partial winding 21w3A and the second partial winding 22w3A.

[0081] In the motor 20A according to the second embodiment, the three U-phase slots Su1A, Su2A, and Su3A are arranged in a concentrated manner. The three V-phase slots Sv1A, Sv2A, and Sv3A are arranged in a concentrated manner, and the three W-phase slots Sw1A, Sw2A, and Sw3A are arranged in a concentrated manner. More specifically, the slots Su1A, Su2A, Su3A, Sv1A, Sv2A, Sv3A, Sw1A, Sw2A, and Sw3A are arranged in this order in the counterclockwise direction in FIG. 8.

[0082] Therefore, the slots Su1A, Su2A, and Su3A corresponding to the U phase are arranged adjacent to each other. The slots Sv1A, Sv2A, and Sv3A corresponding to the V phase are arranged adjacent to each other. The slots Sw1A, Sw2A, and Sw3A corresponding to the W phase are arranged adjacent to each other.

[0083] FIG. 9 is a diagram showing an example of the connection relationship of the U-phase winding in the motor according to the second embodiment. As shown in FIG. 9, the first partial windings 21u1A, 21u2A, and 21u3A are connected in series to form the first winding circuit Cu1A. The second partial windings 22u1A, 22u2A, and 22u3A are connected in series to form the second winding circuit Cu2A. A semiconductor relay 141uA is disposed between the second end of the first winding circuit Cu1A and the first end of the second winding circuit Cu2A. A semiconductor relay 142uA is disposed between the second end of the first winding circuit Cu1A and the second end of the second winding circuit Cu2A. Although the V- and W-phase windings are omitted, the U-, V-, and W-phase windings are connected in the same manner as in the motor 20 according to the first embodiment.

[0084] When the semiconductor relay 141uA is in the off state and the semiconductor relay 142uA is in the on state, the connection state of the U-phase first partial windings 21u1A, 21u2A, 21u3A and second partial windings 22u1A, 22u2A, 22u3A of the motor 20A becomes a first connection state in which the first partial windings 21u1A, 21u2A, 21u3A are connected in series. When the semiconductor relay 141uA is in the on state and the semiconductor relay 142uA is in the off state, the connection state of the first partial windings 21u1A, 21u2A, 21u3A and the second partial windings 22u1A, 22u2A, 22u3A of the U phase of the motor 20A becomes a second connection state in which the first partial windings 21u1A, 21u2A, 21u3A and the second partial windings 22u1A, 22u2A, 22u3A are connected in series.

[0085] [2-2. Winding connection status] Fig. 10A is a diagram illustrating an example of a first connection state of windings in a motor according to the second embodiment, and Fig. 10B is a diagram illustrating an example of a second connection state of windings in a motor according to the second embodiment. In Fig. 10A and Fig. 10B, windings surrounded by dashed lines are windings connected to a power supply (i.e., windings used to drive motor 20A). Windings not surrounded by dashed lines are windings not connected to a power supply (i.e., windings not used to drive motor 20A).

[0086] 10A, in the first connection state of this example, the first partial windings 21u1, 21v1, 21w1, 21u2, 21v2, 21w2, 21u3, 21v3, 21w3, 21u4, 21v4, and 21w4 in all of the slots Su1A, Su2A, Su3A, Sv1A, Sv2A, Sv3A, Sw1A, Sw2A, and Sw3A are used, respectively. Therefore, there is no bias in the slots used, and the motor 20 can be driven efficiently.

[0087] 10B, in the second connection state of this example, the first partial windings 21u1A, 21u2A, 21u3A, 21v1A, 21v2A, 21v3A, 21w1A, 21w2A, and 21w3A and the second partial windings 22u1A, 22u2A, 22u3A, 22v1A, 22v2A, 22v3A, 22w1A, 22w2A, and 22w3A are used in all of the slots Su1A, Su2A, Su3A, Sv1A, Sv2A, Sv3A, Sw1A, Sw2A, and Sw3A, respectively. Therefore, even in the second connection state, there is no bias in the slots used, and the motor 20 can be driven efficiently.

[0088] In the motor of the present disclosure, the windings are divided within the slots, and only a portion of the winding (first partial winding) of one slot may be used, or the entire winding (first partial winding and second partial winding) may be used. Assuming that the magnetic field strengths generated by the first partial winding and the second partial winding are the same (i.e., the inductances of the first partial winding and the second partial winding are the same), using only the first partial winding of one slot can be said to use half (0.5 pieces) of the entire winding of the slot. In other words, the first connection state uses 0.5 windings (first partial windings 21u1A, 21u2A, 21u3A) in each of the U-phase slots Su1A, Su2A, and Su3A, which is equivalent to 0.5 + 0.5 + 0.5 = 1.5 windings connected in series. The second connection state uses one winding (first partial windings 21u1A, 21u2A, 21u3A and second partial windings 22u1A, 22u2A, 22u3A) in each of the U-phase slots Su1A, Su2A, Su3A, and is therefore equivalent to a state in which 1+1+1=3 windings are connected in series.

[0089] Hereinafter, a connection state equivalent to a state in which N windings are connected in series will be referred to as an “N series connection.” For example, the first connection state described above is a “1.5 series connection,” and the second connection state is a “3 series connection.”

[0090] For example, in a three-phase AC permanent magnet synchronous motor in which the windings are not divided in each slot, the connection state in the U phase can be one of the following: a "single series connection" in which the windings in one slot are used, a "two series connection" in which the windings in two slots are connected in series, or a "three series connection" in which the windings in three slots are connected in series. Therefore, in a motor with such a configuration, the winding connection state can be switched between two connection states of the single series connection state, the two series connection state, and the three series connection state (if it is possible to switch between two connection states, a high-speed connection state and a high-torque connection state).

[0091] In the motor 20A according to the second embodiment, the above-described 1.5 series connection can be selected as the connection state.

[0092] Fig. 11 is a graph showing an example of the characteristics (hereinafter also referred to as "NT characteristics") of the motor rotation speed and output torque in each connection state. In the example of Fig. 11, the running resistance graph of motor 20A is shown by a dashed line. The intersection of the running resistance graph and the NT characteristic graph for each connection state is the operating point at the maximum speed in each connection state.

[0093] In the example shown in Figure 11, the operating point at maximum speed in the single-series connection is lower in both rotation speed and torque than the operating points at maximum speed in the double-series connection and the triple-series connection. Therefore, there is no reason to select the single-series connection as a high-speed connection. Furthermore, the operating point at maximum speed in the double-series connection is only slightly higher in rotation speed than the operating point at maximum speed in the triple-series connection. Therefore, the double-series connection is also not suitable for a high-speed connection.

[0094] On the other hand, the operating point in the 1.5 series connection is sufficiently higher in rotation speed than the operating point at maximum speed in the 3 series connection. Therefore, in the motor 20A according to the second embodiment, the 1.5 series connection can be selected as the high rotation speed connection state.

[0095] In particular, when the number of slots (number of teeth) is odd, the number of teeth per phase is odd in a three-phase AC motor. For this reason, in a motor in which the winding in one slot is not divided, the number of winding connections per phase cannot be half of the total windings (for example, if there are three slots per phase, the number of slots used cannot be 1.5). Therefore, in cases where a connection using two slots (two-series connection) does not produce sufficient rotation speed, and a connection using one slot (one-series connection) does not produce enough torque, it is not possible to select an appropriate connection. Even in such cases, dividing the winding in the slot makes it possible to select an appropriate connection (for example, a 1.5-series connection).

[0096] As described above, dividing the windings within the slots increases the number of combinations of winding connection states. Modified examples of winding connection states in the motor according to the second embodiment will be described below. Note that while the winding connection of the U phase will be described below as a representative example, the same applies to the V phase and W phase.

[0097] FIG. 12A is a diagram illustrating a first modified example of the winding connection state in the motor according to the second embodiment. In this first modified example, of the three U-phase slots Su1A, Su2A, and Su3A, the first partial windings 21u1A and 21u2A and the second partial windings 22u1A and 22u2A are used in two slots Su1A and Su2A, and the first partial winding 21u3A is used in one slot Su3A. That is, in the connection state according to the first modified example, the first partial windings 21u1A, 21u2A, and 21u3A and the second partial windings 22u1A and 22u2A are connected in series. This is equivalent to using 2.5 windings in the U-phase. Therefore, the connection state according to the first modified example is a 2.5 series connection.

[0098] 12B is a diagram illustrating a second modified example of the winding connection state in the motor according to the second embodiment. In the first modified example, of the three slots Su1A, Su2A, and Su3A of the U phase, the first partial winding 21u1A and the second partial winding 22u1A are used in one slot Su1A, and the first partial winding 21u2A and 21u3A are used in two slots Su2A and Su3A. That is, in the connection state according to the second modified example, the first partial windings 21u1A, 21u2A, and 21u3A and the second partial winding 22u1A are connected in series. This is equivalent to using two windings in the U phase. Therefore, the connection state according to the second modified example is a two-series connection.

[0099] FIG. 12C is a diagram illustrating a third modified example of the winding connection state in the motor according to the second embodiment. In this third modified example, of the three U-phase slots Su1A, Su2A, and Su3A, the first partial winding 21u1A is used in one slot Su1A, and the first partial winding 21u2A and the second partial winding 22u2A are used in one slot Su2A. The first partial winding 21u3A and the second partial winding 22u3A are not used in one slot Su3A. That is, in the connection state according to the third modified example, the first partial windings 21u1A and 21u2A and the second partial winding 22u2A are connected in series. This is equivalent to using 1.5 windings in the U-phase. Therefore, the connection state according to the third modified example is a 1.5 series connection.

[0100] 12D is a diagram illustrating a fourth modified example of the winding connection state in the motor according to the second embodiment. In the fourth modified example, of the three slots Su1A, Su2A, and Su3A of the U phase, the first partial windings 21u1A and 21u2A are used in two slots Su1A and Su2A, and the first partial winding 21u3A and the second partial winding 22u3A are not used in the one slot Su3A. That is, in the connection state according to the fourth modified example, the first partial windings 21u1A and 21u2A are connected in series. This is equivalent to using one winding in the U phase. Therefore, the connection state according to the fourth modified example is a single series connection.

[0101] FIG. 12E is a diagram illustrating a fifth modified example of the winding connection state in the motor according to the second embodiment. In this fifth modified example, of the three slots Su1A, Su2A, and Su3A of the U phase, the first partial winding 21u1A is used in one slot Su1A, and the first partial windings 21u2A and 21u3A and the second partial windings 22u2A and 22u3A are not used in the two slots Su2A and Su3A. That is, in the connection state according to the fifth modified example, only the first partial winding 21u1A is used. This is equivalent to using 0.5 windings in the U phase. Therefore, the connection state according to the fifth modified example is a 0.5 series connection.

[0102] The first to fifth modified examples are only some of the variations in the connection state of the windings of the motor 20A, and other connection states also exist.

[0103] As described above, in motor 20A according to the second embodiment, the winding connection states of the first to fifth modifications can be selected instead of at least one of the first and second connection states, or in addition to the first and second connection states. This makes it possible to select multiple connection states suited to the running characteristics (running resistance) of the vehicle from among more connection states than before, and to switch between the selected multiple connection states.

[0104] [3. Other Modifications] The configurations of the motors according to the first and second embodiments described above are merely examples and are not intended to limit the scope of the present invention. For example, in a permanent magnet synchronous motor with a different number of poles and slots, such as 8 poles and 12 slots and 8 poles and 9 slots, the winding may be divided in each slot. Furthermore, the number of divisions of the winding in each slot does not have to be two. For example, the winding in each slot may be divided into three or more partial windings. For example, if the winding in a slot is divided into a first partial winding, a second partial winding, and a third partial winding, the second connection state is such that the first partial winding, the second partial winding, and the third partial winding are connected in series (i.e., the second circuit includes a series-connected circuit of the first partial winding, the second partial winding, and the third partial winding).

[0105] [4. Supplementary Notes] The embodiments disclosed herein are illustrative in all respects and are not restrictive. The scope of the present invention is defined by the claims rather than the above-described embodiments, and includes meanings equivalent to the claims and all modifications within the scope thereof. [Explanation of symbols]

[0106] 10 Winding switching system 20 Motor 21, 21u1, 21u2, 21u3, 21u4, 21v1, 21v2, 21v3, 21v4, 21w1, 21w2, 21w3, 21w4 First partial winding 22, 22u1, 22u2, 22u3, 22u4, 22v1, 22v2, 22v3, 22v4, 22w1, 22w2, 22w3, 22w4 Second partial winding 25 Power Lines 30 Power Converter 31u, 32u, 31v, 32v, 31w, 32w switches 33u,33v,33w current sensor 35u,35v,35w power line 40 Battery 50 Control device 100 Winding switching device 102u, 102v, 102w zero cross detection circuit 103u, 103v, 103w control circuit 131u, 131v, 131w current sensor 140u, 140v, 140w switching circuit 141u, 142u, 141v, 142v, 141w, 142w solid state relays 210 Stator 210Y York 210T,210Tu1,210Tv1,210Tw1,210Tu2,210Tv2,210Tw2,210Tu3,210Tv3,210Tw3,210Tu4,210Tv4,210Tw4 Teeth 220 rotor 220M permanent magnet 241u,242u,243u,251u,252u,253u,241v,242v,243v,251v,252v,253v,241w,242w,243w,251w,252w,253w power line Su1,Sv1,Sw1,Su2,Sv2,Sw2,Su3,Sv3,Sw3,Su4,Sv4,Sw4 slots Cu1, Cv1, Cw1 First winding circuit Cu2, Cv2, Cw2 Second winding circuit 20A motor 21u1A, 21u2A, 21u3A, 21v1A, 21v2A, 21v3A, 21w1A, 21w2A, 21w3A First partial winding 22u1A, 22u2A, 22u3A, 22v1A, 22v2A, 22v3A, 22w1A, 22w2A, 22w3A Second partial winding 210A Stator 210Tu1A,210Tu2A,210Tu3A,210Tv1A,210Tv2A,210Tv3A,210Tw1A,210Tw2A,210Tw3A Teeth 220A rotor Su1A, Su2A, Su3A, Sv1A, Sv2A, Sv3A, Sw1A, Sw2A, Sw3A slots

Claims

1. a plurality of first partial windings wound around the plurality of teeth, respectively; a plurality of second partial windings wound around the plurality of teeth, respectively; Equipped with a first connection state in which first circuits of each phase including the first partial windings are connected to each other; a second connection state in which second circuits of each phase including a series-connected circuit of the first partial winding and the second partial winding are connected to each other; configured to be switchable between Polyphase AC motor.

2. a first phase slot corresponding to a first phase and including the first partial winding and the second partial winding wound around the same tooth, and a second phase slot corresponding to a second phase and including the first partial winding and the second partial winding wound around the same tooth, are adjacent to each other; the second phase slot is adjacent to a third phase slot corresponding to a third phase, the third phase slot including the first partial winding and the second partial winding wound around the same tooth; 2. The polyphase AC motor according to claim 1.

3. a plurality of first phase slots corresponding to a first phase, each including the first partial winding and the second partial winding wound around the same tooth, are arranged in a row; a plurality of second phase slots corresponding to a second phase, each including the first partial winding and the second partial winding wound around the same tooth, are arranged in a row; a plurality of third phase slots corresponding to a third phase, each including the first partial winding and the second partial winding wound around the same tooth, are arranged in a row; 2. The polyphase AC motor according to claim 1.

4. The number of teeth is odd.

4. The polyphase AC motor according to claim 3.

5. the first circuit corresponding to the first phase includes a first series connection circuit in which the first partial winding wound around the first tooth corresponding to the first phase, the first partial winding wound around the second tooth corresponding to the first phase, and the second partial winding wound around the second tooth are connected in series; The polyphase AC motor according to any one of claims 1 to 4.

6. the first circuit corresponding to the first phase includes a second series-connected circuit in which the first partial winding wound around the first tooth corresponding to the first phase, the first partial winding wound around the second tooth corresponding to the first phase, and the first partial winding wound around the third tooth corresponding to the first phase are connected in series; The polyphase AC motor according to any one of claims 1 to 4.

7. the second circuit corresponding to the first phase includes a third series-connected circuit in which the first partial winding wound around the first tooth, the second partial winding wound around the first tooth, the first partial winding wound around the second tooth, and the second partial winding wound around the second tooth are connected in series; 6. The polyphase AC motor according to claim 5.

8. The second circuit corresponding to the first phase includes a fourth series connection circuit in which the first partial winding wound on the first tooth, the second partial winding wound on the first tooth, the first partial winding wound on the second tooth, the second partial winding wound on the second tooth, the first partial winding wound on a third tooth corresponding to the first phase, and the second partial winding wound on the third tooth are connected in series.

6. The polyphase AC motor according to claim 5.

9. the first connection state; the second connection state; a third connection state in which third circuits of respective phases different from the first circuit and the second circuit are connected to each other; configured to be switchable between The polyphase AC motor according to any one of claims 1 to 4.

10. a polyphase AC motor capable of switching a connection state of a plurality of windings between a first connection state and a second connection state; a power converter that converts power output from a power supply into AC power and supplies the AC power to the AC motor; a winding switching device for switching the connection state of the plurality of windings; Equipped with The polyphase AC motor comprises: a plurality of first partial windings wound around the plurality of teeth, respectively; a plurality of second partial windings wound around the plurality of teeth, respectively; Including, the first connection state is a connection state in which first circuits of each phase including the first partial winding are connected to each other, the second connection state is a connection state in which second circuits of each phase, each including a series-connected circuit of the first partial winding and the second partial winding, are connected to each other; Winding switching system.

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