Coil switching system for vehicle motor, control device, method for controlling vehicle motor, and computer program

Abstract

This winding switching system is provided with: a drive motor for driving wheels of a vehicle; a control device for controlling the drive motor; and a power converter for converting direct-current power output from a battery into alternating-current power and supplying the alternating-current power to the drive motor. And a winding switching device for switching the connection state of a plurality of windings in the drive motor between a first connection state and a second connection state, the control device comprising a torque control unit and a switching control unit, the torque control unit changes the output torque of the drive motor by changing the alternating current output from the power converter at a predetermined shift timing of the vehicle. The switching control unit switches the winding switching device from the first connection state to the second connection state after the AC current has changed.

Description

Technical Field

[0001] The present disclosure relates to a winding switching system for a vehicle motor, a control device, a control method for a vehicle motor, and a computer program. This application claims priority based on Japanese application No. 2022-162243 filed on October 7, 2022, and all the contents described in the Japanese application are cited by reference. Background Art

[0002] Patent document 1 discloses that in a vehicle in which wheels are driven by a drive motor such as an electric vehicle or hybrid vehicle that does not have a stepped transmission, simulated gear shifting is performed by executing torque variation control, wherein the torque variation control is a control that increases the torque of the drive motor after reducing a set variation amount.

[0003] Prior Art Literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2018-166386 Summary of the invention

[0006] A winding switching system for a vehicle motor in one embodiment of the present invention comprises: a drive motor for driving the wheels of a vehicle; a control device for controlling the drive motor; a power converter for converting DC power output from a battery into AC power and supplying the AC power to the drive motor; and a winding switching device for switching the connection state of multiple windings in the drive motor between a first connection state and a second connection state, the control device including: a torque control unit for changing the output torque of the drive motor by changing the AC current output from the power converter at a predetermined speed change timing of the vehicle; and a switching control unit for switching the winding switching device from the first connection state to the second connection state after the AC current changes.

[0007] The present disclosure can be implemented not only as a winding switching system for a vehicle motor having the above-mentioned characteristic structure, but also as a control device included in the winding switching system for a vehicle motor, or as a control method for a vehicle motor having characteristic processing in the control device as steps. The present disclosure can be implemented as a computer program that causes a computer to function as a control device, or a part or all of the control device can be implemented as a semiconductor integrated circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 This is a diagram showing an example of the configuration of the winding switching system according to the first embodiment.

[0009] Figure 2 This is a block diagram showing an example of the hardware configuration of the control device.

[0010] Figure 3 This is a circuit diagram showing an example of the structure of the winding switching device according to the first embodiment.

[0011] Figure 4 This is a time chart showing an example of the switching timing of the windings of the motor in the winding switching system according to the first embodiment.

[0012] Figure 5 This is a flowchart showing an example of the electric upshift process performed by the control device according to the first embodiment.

[0013] Figure 6 This is a flowchart showing an example of the electric downshift process performed by the control device according to the first embodiment.

[0014] Figure 7 This is a circuit diagram showing an example of the structure of the winding switching device according to the second embodiment.

[0015] Figure 8 This is a time chart showing an example of the switching timing of the motor windings in the winding switching system according to the third embodiment.

[0016] Fig. 9 This is a time chart showing an example of the switching timing of the windings of the motor in the winding switching system according to the fourth embodiment.

[0017] Fig.10 This is a time chart showing an example of the pseudo speed change control process in the winding switching system according to the fifth embodiment.

[0018] Fig.11 This is a flowchart showing an example of pseudo speed change processing performed by the control device according to the fifth embodiment.

[0019] Fig.12 This is a functional block diagram showing an example of functions of the control device according to the sixth embodiment.

[0020] Fig.13 1 is a flowchart showing an example of a forced upshift determination process performed by the control device according to the sixth embodiment.

[0021] Fig.14 This is a flowchart showing an example of forced downshift determination processing performed by the control device according to the sixth embodiment. DETAILED DESCRIPTION

[0022] <Problems to be Solved by the Present Disclosure>

[0023] The pseudo shift in the vehicle disclosed in Patent Document 1 is achieved by sacrificing the running performance of the vehicle instead of actually performing a gear change by the step-variable transmission.

[0024] <Effects of the Present Disclosure>

[0025] According to the present disclosure, it is possible to efficiently utilize the performance of the driving motor of the electric vehicle and provide the driver with the same shifting feeling as that of a step-variable transmission.

[0026] <Overview of Embodiments of the Present Disclosure>

[0027] Hereinafter, the outline of the embodiments of the present disclosure will be listed and described.

[0028] (1) The winding switching system for a motor for a vehicle of the present embodiment comprises: a drive motor for driving a wheel of a vehicle; a control device for controlling the drive motor; a power converter for converting DC power output from a battery into AC power and supplying the AC power to the drive motor; and a winding switching device for switching the connection state of a plurality of windings in the drive motor between a first connection state and a second connection state, wherein the control device includes: a torque control unit for changing the output torque of the drive motor by changing the AC current output from the power converter at a predetermined speed change timing of the vehicle; and a switching control unit for switching the winding switching device from the first connection state to the second connection state after the AC current changes. Thus, the connection state of the windings of the drive motor is switched from the first connection state to the second connection state, so that the performance of the drive motor can be efficiently utilized, and a speed change equivalent to a speed change based on a mechanical transmission can be achieved (hereinafter also referred to as "electric speed change"). Moreover, the output torque of the drive motor is changed in accordance with the switching of the connection state of the windings of the drive motor, thereby providing the driver with the same speed change feeling as a mechanical transmission.

[0029] (2) In the above (1), the torque control unit may reduce the output torque of the drive motor by reducing the AC current output from the power converter at the first speed change timing, and the switching control unit may switch the winding switching device from the first connection state to the second connection state after the AC current is reduced to below the first target value. In this way, electric speed change similar to upshifting by a mechanical transmission can be achieved during the period of vehicle acceleration or speed maintenance.

[0030] (3) In the above (2), the torque control unit may reduce the output torque of the drive motor by reducing the AC current output from the power converter at a second speed change timing different from the first speed change timing, and the switching control unit may switch the winding switching device from the second connection state to the first connection state after the AC current is reduced to less than the first target value. In this way, electric speed change similar to downshifting by a mechanical transmission can be achieved during vehicle acceleration or speed maintenance.

[0031] (4) In the above (1), the torque control unit may increase the output torque of the drive motor by increasing the AC current output from the power converter at the first speed change timing, and the switching control unit may switch the winding switching device from the first connection state to the second connection state after the AC current increases to a second target value or more. Thus, electric speed change similar to upshifting by a mechanical transmission can be achieved during the period when the drive motor performs regenerative braking.

[0032] (5) In the above (4), the torque control unit may increase the output torque of the drive motor by increasing the AC current output from the power converter at a second speed change timing different from the first speed change timing, and the switching control unit may switch the winding switching device from the second connection state to the first connection state after the AC current increases to a second target value or more. Thus, electric speed change similar to downshifting by a mechanical transmission can be achieved during the period of regenerative braking of the drive motor.

[0033] (6) In any one of the above (1) to (5), the second connection state may be a connection state for the drive motor to output a torque lower than that of the first connection state at the same rotation speed. Thus, the connection state of the winding of the drive motor can be switched between the first connection state of high torque and low speed and the second connection state of low torque and high speed.

[0034] (7) In the above (6), the control device may further include a first determination unit that determines the timing before the induced voltage generated in the winding exceeds the output voltage of the battery when the connection state of the plurality of windings is the first connection state as the first forced speed change timing, the torque control unit changes the output torque of the drive motor by changing the AC current output from the power converter at the first forced speed change timing determined by the first determination unit, and the switching control unit switches the winding switching device from the first connection state to the second connection state after the AC current changes. When the induced voltage generated in the winding exceeds the output voltage of the battery, the current flowing in the winding cannot be changed to zero. When the connection state of the winding is switched by the relay in a state where current is flowing in the winding, the relay may be damaged. With the above structure, when the connection state of the winding is switched from the first connection state to the second connection state, the current flowing in the winding can be suppressed and the relay can be protected.

[0035] (8) In the above (7), the first determination unit may determine the first forced speed change timing as the timing when the physical quantity related to the induced voltage exceeds a first threshold value corresponding to the output voltage of the battery. Thus, the timing before the induced voltage exceeds the output voltage of the battery can be accurately determined using the physical quantity related to the induced voltage.

[0036] (9) In the above (8), the physical quantity may be one of the voltage in the winding, the rotation speed of the drive motor, the current flowing in the winding, and the output torque of the drive motor. Thus, the timing before the induced voltage exceeds the output voltage of the battery can be accurately determined based on one of the voltage in the winding, the rotation speed of the motor, the current flowing in the winding, and the output torque of the motor that can be easily detected by the sensor.

[0037] (10) In any one of the above (7) to (9), the control device may further include: a determination unit, when the connection state of the plurality of windings is the second connection state, determining whether the induced voltage after the connection state of the winding is switched from the second connection state to the first connection state exceeds the output voltage of the battery; and a prohibition unit, when the determination unit determines that the induced voltage exceeds the output voltage of the battery, prohibiting the switching control of the connection state of the winding by the switching control unit. Thus, the induced voltage of the winding is prevented from exceeding the output voltage of the battery after the connection state of the winding is switched from the second connection state to the first connection state. Therefore, the relay can be protected from damage.

[0038] (11) In any one of the above (7) to (10), it is possible that the control device also includes a second determination unit, which determines the timing after the induced voltage becomes less than the output voltage of the battery after the connection state of the winding is switched from the second connection state to the first connection state when the connection state of the plurality of windings is the second connection state as the second forced speed change timing, the torque control unit changes the output torque of the drive motor by changing the AC current output from the power converter at the second forced speed change timing determined by the second determination unit, and the switching control unit switches the winding switching device from the second connection state to the first connection state after the AC current changes. Thereby, the induced voltage of the winding is prevented from exceeding the output voltage of the battery after the connection state of the winding is switched from the second connection state to the first connection state. Therefore, the relay can be protected from damage.

[0039] (12) In the above (11), the second determination unit may determine the second forced shift timing as the timing when the physical quantity related to the induced voltage becomes less than a second threshold value corresponding to the output voltage of the battery. Thus, the timing after the induced voltage becomes less than the output voltage of the battery can be accurately determined using the physical quantity related to the induced voltage.

[0040] (13) In any one of the above (1) to (12), the winding switching system may further include an input device for receiving a speed change instruction from a driver, and the speed change timing is a timing when the input device receives the speed change instruction from the driver. Thus, the drive motor can perform electric speed change according to the speed change instruction from the driver.

[0041] (14) In any one of the above (1) to (12), the speed change timing may be a timing determined based on the rotation speed of the drive motor, the output torque, the acceleration indication amount in the vehicle, and the braking indication amount in the vehicle. Thus, the drive motor can perform electric speed change at a timing determined based on the motor rotation speed, the output torque, the acceleration indication amount (the amount of accelerator pedal depression), and the braking indication amount (the amount of brake pedal depression).

[0042] (15) In any one of the above (1) to (14), the torque control unit may decrease or increase the effective current of the AC current output from the power converter starting from the speed change timing. This allows the torque to change smoothly, and can provide a natural speed change feeling to the driver.

[0043] (16) In the above (15), the torque control unit may change the effective current in a ramp shape starting from the speed change timing. This can provide the driver with a speed change feeling of a smooth torque change.

[0044] (17) In any one of the above (1) to (14), the torque control unit may change the effective current of the AC current output from the power converter in a step-like manner based on the speed change timing. This can provide the driver with a speed change feeling of a sudden torque change.

[0045] (18) In any one of the above (1) to (17), the torque control unit may perform a simulated speed change control process, which is a process of reducing the AC current output from the power converter at a simulated speed change timing different from the speed change timing and then increasing it. Thus, in addition to the electric speed change, the drive motor also performs a simulated speed change. Therefore, it is possible to provide the driver with a multi-stage speed change feeling.

[0046] (19) The control device of the present embodiment controls a drive motor that drives wheels of a vehicle, and the control device comprises: a torque control unit that changes the output torque of the drive motor by changing the AC current output from a power converter at a predetermined speed change timing of the vehicle, the power converter converting DC power output from a battery into AC power and supplying the AC power to the drive motor; and a switching control unit that switches a winding switching device that switches the connection state of a plurality of windings in the drive motor from a first connection state to a second connection state after the AC current changes. Thus, the connection state of the windings of the drive motor is switched from the first connection state to the second connection state, so that the performance of the drive motor can be efficiently utilized and electric speed change can be achieved. Moreover, the output torque of the drive motor is changed along with the switching of the connection state of the windings of the drive motor, thereby providing the driver with the same speed change feeling as a mechanical transmission.

[0047] (20) The vehicle motor control method of the present embodiment is executed by a control device for controlling a drive motor that drives the wheels of a vehicle, and the vehicle motor control method includes the following steps: changing the output torque of the drive motor by changing the AC current output from a power converter at a predetermined speed change timing of the vehicle, the power converter converting the DC power output from a battery into AC power and supplying the AC power to the drive motor; and switching a winding switching device that switches the connection state of a plurality of windings in the drive motor from a first connection state to a second connection state after the AC current changes. Thus, the connection state of the windings of the drive motor is switched from the first connection state to the second connection state, so that the performance of the drive motor can be efficiently utilized and electric speed change can be achieved. Moreover, the output torque of the drive motor is changed in conjunction with the switching of the connection state of the windings of the drive motor, thereby providing the driver with the same speed change feeling as a mechanical transmission.

[0048] (21) The computer program of the present embodiment is used by a control device for controlling a drive motor that drives wheels of a vehicle, wherein the computer program causes a computer to execute the following steps: changing the output torque of the drive motor by changing the AC current output from a power converter at a predetermined speed change timing of the vehicle, the power converter converting DC power output from a battery into AC power and supplying the AC power to the drive motor; and switching a winding switching device that switches the connection state of a plurality of windings in the drive motor from a first connection state to a second connection state after the AC current changes. Thus, the connection state of the windings of the drive motor is switched from the first connection state to the second connection state, thereby making it possible to efficiently utilize the performance of the drive motor and realize electric speed change. Furthermore, the output torque of the drive motor is changed in conjunction with the switching of the connection state of the windings of the drive motor, thereby making it possible to provide the driver with the same speed change feeling as a mechanical transmission.

[0049] <Details of the embodiments of the present disclosure>

[0050] Hereinafter, the details of the embodiments of the present invention will be described with reference to the drawings. It should be noted that at least a part of the embodiments described below may be arbitrarily combined.

[0051] [1. First embodiment]

[0052] [1-1. Winding switching system]

[0053] Figure 1 This is a diagram showing an example of the configuration of the winding switching system according to the first embodiment.

[0054] The winding switching system 10 is mounted on a motor-propelled vehicle such as an electric vehicle or a plug-in hybrid vehicle (hereinafter referred to as an “electric 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 .

[0055] The motor 20 is a motor for driving that generates propulsion force for the electric vehicle. That is, the motor 20 is a drive motor that is connected to the wheel 60 and drives the wheel 60. The motor 20 is driven by three-phase AC power. An example of the motor 20 is a permanent magnet synchronous motor.

[0056] The battery 40 is a battery for supplying electric power for driving the motor 20. The battery 40 is a secondary battery, for example, a lithium ion battery.

[0057] Power converter 30 is an inverter that converts DC power supplied from battery 40 into three-phase AC power. Power converter 30 may also have a function of converting three-phase AC power output by motor 20 when functioning as a generator into DC power to charge battery 40.

[0058] The power converter 30 includes legs for each phase of the U phase, the V phase, and the W phase. The legs for the U phase include switches 31u and 32u, the legs for the V phase include switches 31v and 32v, and the legs for the W phase include switches 31w and 32w. The DC power is converted into three-phase AC power by opening and closing the switches 31u, 32u, 31v, 32v, 31w, and 32w. The switches 31u, 32u, 31v, 32v, 31w, and 32w are, for example, IGBTs (Insulated Gate Bipolar Transistors) or power MOSFETs (Metal Oxide Semiconductor Field-Effect Transistors).

[0059] The power line 35u corresponding to U extends from the leg of the U phase, the power line 35v corresponding to V extends from the leg of the V phase, and the power line 35w corresponding to W extends from the leg of the W phase. 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 current Iu of the U phase. The current sensor 33v detects the current value of the current Iv of the V phase. The current sensor 33w detects the current value of the current Iw of the W phase. The current sensors 33u, 33v, 33w can detect the current values ​​of the currents Iu, Iv, Iw flowing in the power lines 35u, 35v, 35w, including the DC component and the AC component. The current sensors 33u, 33v, 33w are, for example, DCCT (direct current transformer) or shunt resistors.

[0060] The winding switching device 100 is arranged 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 a plurality of power lines 25. The winding switching device 100 switches the connection state of the plurality of windings of the motor 20. The structure of the winding switching device 100 will be described later. The 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.

[0061] The control device 50 controls the motor 20. Specifically, the control device 50 controls the motor 20 by controlling the power converter 30 and the winding switching device 100. Signal lines extend from the control device 50 to the switches 31u, 32u, 31v, 32v, 31w, and 32w, respectively, and the control device 50 controls the on / off timing of the switches 31u, 32u, 31v, 32v, 31w, and 32w. The signal line extends from the control device 50 to the winding switching device 100, and the control device 50 outputs a switching instruction signal for instructing the switching of the connection state of the winding to the winding switching device 100.

[0062] The control device 50 is connected to a sensor 71 that detects the depression amount of the brake pedal 70 and receives a detection signal output from the sensor 71. The control device 50 is connected to a sensor 81 that detects the depression amount of the accelerator pedal 80 and receives a detection signal output from the sensor 81.

[0063] A rotation sensor 201 for detecting the rotation speed of the motor 20 and a torque sensor 202 for detecting the output torque of the motor 20 are mounted on the output shaft of the motor 20. The rotation sensor 201 and the torque sensor 202 are connected to the control device 50. The control device 50 receives a detection signal output from the rotation sensor 201 and receives a detection signal output from the torque sensor 202.

[0064] The control device 50 is connected to the speed indicator 90. The speed indicator 90 is an input device for the driver to input a speed change instruction. The speed indicator 90 is, for example, a shift lever. In other examples, the speed indicator 90 is a switch for the driver to indicate whether to shift up or down. The speed indicator 90 outputs a speed change instruction signal according to the driver's operation. The control device 50 receives the speed change instruction signal output from the speed indicator 90.

[0065] Figure 2 2 is a block diagram showing an example of a hardware configuration of a control device. The control device 50 includes a processor 501 , a nonvolatile memory 502 , a volatile memory 503 , and an interface (I / F) 504 .

[0066] The volatile memory 503 is a semiconductor memory such as SRAM (Static Random Access Memory) and DRAM (Dynamic Random Access Memory). The non-volatile memory 502 is, for example, a flash memory, a hard disk, a ROM (Read Only Memory), etc. The non-volatile memory 502 stores a motor control program 510 as a computer program and data used in the execution of the motor control program 510. The various functions of the control device 50 are performed by executing the motor control program 510 using the processor 501. The motor control program 510 can be stored in a recording medium such as a flash memory, a ROM, and a CD-ROM. The processor 501 controls the power converter 30 and the winding switching device 100 through the motor control program 510.

[0067] The processor 501 is, for example, a CPU (Central Processing Unit). However, the processor 501 is not limited to a CPU. The processor 501 may also be a GPU (Graphics Processing Unit). The processor 501 is, for example, a multi-core processor. The processor 501 may also be a single-core processor. The processor 501 may also be, for example, an ASIC (Application Specific Integrated Circuit), or a programmable logic device such as a gate array or an FPGA (Field Programmable Gate Array). In this case, the ASIC or the programmable logic device is configured to be able to perform the same processing as the motor control program 510.

[0068] I / F504 is connected to the rotation sensor 201, the torque sensor 202, the sensor 71, the sensor 81, and the speed indicator 90. I / F504 is, for example, an input / output interface or a communication interface. I / F504 receives a detection signal of the rotation speed of the motor 20 output from the rotation sensor 201. I / F504 receives a detection signal of the output torque of the motor 20 output from the torque sensor 202. I / F504 receives a detection signal of the brake pedal depression amount output from the sensor 71. I / F504 receives a detection signal of the accelerator pedal depression amount output from the sensor 81. I / F504 receives a speed change indication signal output from the speed indicator 90.

[0069] [1-2. Structure of winding switching device]

[0070] Figure 3 2 is a circuit diagram showing an example of the structure of the winding switching device of the first embodiment. The motor 20 includes a plurality of windings 21u, 22u, 21v, 22v, 21w, and 22w. The windings 21u and 22u correspond to U, the windings 21v and 22v correspond to V, and the windings 21w and 22w correspond to W. However, the number of windings of each phase is not limited to two, and may be three or more. The windings 22u, 22v, and 22w are connected at a neutral point 23.

[0071] The winding switching device 100 switches the connection state of the windings 21u, 22u, 21v, 22v, 21w, 22w between a series connection state and a parallel connection state for each phase. The winding switching device 100 includes control circuits 103u, 103v, 103w and switching circuits 104u, 104v, 104w.

[0072] The switching circuits 104u, 104v, 104w switch the connection state of the windings 21u, 22u, 21v, 22v, 21w, 22w between the series connection state and the parallel connection state according to the control from the control device 50. The series connection state is an example of the first connection state, and the parallel connection state is an example of the second connection state.

[0073] Hereinafter, the U phase will be described representatively using the connection relationship between the winding switching device 100, the power line 35u, and the motor 20. The V phase and the W phase are the same, so the description thereof will be omitted.

[0074] The power line 35u is connected to one end of the winding 21u. The power line 212u extends from the other end of the winding 21u. The power line 221u extends from one end of the winding 22u, and the power line 222u extends from the other end of the winding 22u.

[0075] The switching circuit 104u includes semiconductor relays 111u, 112u, and 113u. The semiconductor relays 111u, 112u, and 113u are, for example, IGBTs or power MOSFETs.

[0076] The power line 35u is introduced into the interior of the winding switching device 100. In the winding switching device 100, the power line 35u branches at the middle point and is connected to the first terminal of the semiconductor relay 111u. The second terminal of the semiconductor relay 111u is connected to the first terminal of the semiconductor relay 112u. At the connection point between the second terminal of the semiconductor relay 111u and the first terminal of the semiconductor relay 112u, a power line 221u extending from the winding 22u is connected. The power lines 212u, 221u, 222u extend from the motor 20 and are introduced into the interior of the winding switching device 100.

[0077] The second terminal of the semiconductor relay 112u is connected to the first terminal of the semiconductor relay 113u. A power line 212u extending from the winding 21u is connected to the connection point between the second terminal of the semiconductor relay 112u and the first terminal of the semiconductor relay 113u. The second terminal of the semiconductor relay 113u is connected to the power line 222u extending from the winding 22u.

[0078] When the semiconductor relays 111u and 113u are in the OFF state and the semiconductor relay 112u is in the ON state, the windings 21u and 22u are connected in series. When the semiconductor relays 111u and 113u are in the ON state and the semiconductor relay 112u is in the OFF state, the windings 21u and 22u are connected in parallel.

[0079] The gate terminals of the semiconductor relays 111u, 112u, and 113u are connected to signal lines extending from the control circuit 103u, respectively. The signal lines extending from the control device 50 are connected to the control circuit 103u.

[0080] The control circuit 103u performs on / off control of the semiconductor relays 111u, 112u, and 113u by applying gate voltages individually to the gate terminals of the semiconductor relays 111u, 112u, and 113u. Specifically, when the control circuit 103u receives a switching instruction from the control device 50 that the connection state of the windings 21u and 22u is switched from the series connection state to the parallel connection state, the semiconductor relays 111u and 113u are set to the on state, and the semiconductor relay 112u is set to the off state. When the control circuit 103u receives a switching instruction from the control device 50 that the connection state of the windings 21u and 22u is switched from the parallel connection state to the series connection state, the semiconductor relays 111u and 113u are set to the off state, and the semiconductor relay 112u is set to the on state.

[0081] The control circuit 103u is composed of, for example, a plurality of logic circuits (AND circuits, NOT circuits, latch circuits, etc.). In other examples, the control circuit 103u is composed of a processor. For example, the control circuit 103u is composed of a single-chip microcomputer. The control circuit 103u may also be composed of a programmable logic device such as an ASIC or an FPGA.

[0082] [1-3. Functions of control device]

[0083] Back to Figure 1 , the functions of the control device 50 will be described. The control device 50 has the functions of a torque control unit 511 and a switching control unit 512. The functions of the torque control unit 511 and the switching control unit 512 are realized by the processor 501 executing the motor control program 510.

[0084] The torque control unit 511 changes the output torque of the motor 20 by changing the AC current output from the power converter 30 at a predetermined speed change timing of the electric vehicle. The switching control unit 512 changes the connection state of the windings 21u, 22u, 21v, 22v, 21w, and 22w of the motor 20 by the winding switching device 100 after the AC current output from the power converter 30 changes.

[0085] The speed change timing is, for example, the timing at which the control device 50 receives the speed change instruction output from the speed change indicator 90. That is, in a vehicle equipped with the speed change indicator 90, when the driver uses the speed change indicator 90 to instruct a speed change, the control device 50 changes the AC current output from the power converter 30 starting from the timing at which the speed change instruction is input to the control device 50.

[0086] In another example, the speed change timing is a timing determined based on the rotation speed of the motor 20, the output torque of the motor 20, the depression amount of the brake pedal 70 (the braking instruction amount), and the depression amount of the accelerator pedal 80 (the acceleration instruction amount). That is, an automatic speed change control device (not shown) in the vehicle generates a speed change instruction based on the rotation speed of the motor 20, the output torque of the motor 20, the depression amount of the brake pedal 70 (the braking instruction amount), and the depression amount of the accelerator pedal 80 (the acceleration instruction amount), and inputs the generated speed change instruction to the control device 50. With regard to the speed change timing, when the speed change instruction generated by such an automatic speed change control device is input to the control device 50, the control device 50 changes the AC current output from the power converter 30 from the timing when the speed change instruction is input to the control device 50.

[0087] When the windings 21u, 22u, 21v, 22v, 21w, and 22w of the motor 20 are connected in series, the motor 20 can output a high torque. When the windings 21u, 22u, 21v, 22v, 21w, and 22w of the motor 20 are connected in parallel, the output torque of the motor 20 is reduced compared to the series connection state at the same speed. That is, the series connection state of the windings 21u, 22u, 21v, 22v, 21w, and 22w is a state in which the motor 20 has a low rotation speed and a high torque, and the parallel connection state of the windings 21u, 22u, 21v, 22v, 21w, and 22w is a state in which the motor 20 has a high rotation speed and a low torque. Switching the connection state of the windings 21u, 22u, 21v, 22v, 21w, 22w of the motor 20 from the series connection state to the parallel connection state is equivalent to upshifting in a mechanical transmission, and switching the connection state of the windings 21u, 22u, 21v, 22v, 21w, 22w of the motor 20 from the parallel connection state to the series connection state is equivalent to downshifting in a mechanical transmission. Switching the connection state of the windings 21u, 22u, 21v, 22v, 21w, 22w of the motor 20 from the series connection state to the parallel connection state is also called "electric upshifting", and switching the connection state of the windings 21u, 22u, 21v, 22v, 21w, 22w of the motor 20 from the parallel connection state to the series connection state is also called "electric downshifting".

[0088] For example, the torque control unit 511 reduces the output torque of the motor 20 by reducing the AC current output from the power converter 30 at the first speed change timing. After the AC current output from the power converter 30 is reduced to below the first target value, the switching control unit 512 causes the winding switching device 100 to switch the connection state of the windings 21u, 22u, 21v, 22v, 21w, and 22w of the motor 20 from the series connection state to the parallel connection state. The first speed change timing is the timing that indicates the electric upshift.

[0089] Figure 4 2 is a time chart showing an example of the switching timing of the windings 21u, 22u, 21v, 22v, 21w, and 22w of the motor 20 in the winding switching system of the first embodiment. Figure 4 1 shows an example of a speed change instruction when the connection state of the windings 21u, 22u, 21v, 22v, 21w, 22w of the motor 20 is switched from a series connection state to a parallel connection state, a current supplied to the motor 20 (hereinafter also referred to as a "motor current"), an output torque of the motor 20 (hereinafter also referred to as a "motor torque"), and a timing of on / off switching of the semiconductor relays 111u, 112u, 113u, 111v, 112v, 113v, 111w, 112w, 113w. It should be noted that, hereinafter, the semiconductor relays 111u, 111v, 111w are collectively referred to as "relay 111", the semiconductor relays 112u, 112v, 112w are collectively referred to as "relay 112", and the semiconductor relays 113u, 113v, 113w are collectively referred to as "relay 113".

[0090] At time t11, a speed change instruction (electric downshift instruction) is input to the control device 50. The torque control unit 511 starts to reduce the motor current Iq from time t11. The motor current Iq is the effective current (Q-axis current) of the AC current applied to the motor 20. Figure 4 In the example shown, the motor current Iq decreases gradually in a ramp shape. As the motor current Iq decreases, the motor torque also decreases.

[0091] At time t12, the motor current Iq reaches the first target value Th1. The torque control unit 511 stops the reduction of the motor current Iq from time t12 when the motor current Iq reaches the first target value Th1. That is, the motor current Iq is maintained at the first target value Th1 after time t12. The reduction of the motor torque also stops after time t12.

[0092] The switching control unit 512 switches the connection state of the windings 21u, 22u, 21v, 22v, 21w, and 22w from the series connection state to the parallel connection state at a timing after time t12. Figure 4 In the example, at time t01 later than time t12, the relays 111 and 113 are switched from the on state to the off state, and at time t02 later than time t01, the relay 112 is switched from the off state to the on state. During the period between time t01 and time t02, the relays 111, 112, and 113 are all in the off state. Thus, when the connection states of the windings 21u, 22u, 21v, 22v, 21w, and 22w are switched, the relays 111, 112, and 113 are prevented from all becoming in the on state.

[0093] From time t21 later than time t02, the torque control unit 511 increases the motor current Iq. The target value of the motor current Iq at this time is determined based on the target torque in the parallel connection state of the windings 21u, 22u, 21v, 22v, 21w, and 22w. The target torque is determined based on the rotation speed of the motor 20, the output torque of the motor 20, the depression amount of the brake pedal 70 (the braking indication amount), and the depression amount of the accelerator pedal 80 (the acceleration indication amount). Figure 4 In the example shown, the motor current Iq increases in a ramp shape. As the motor current Iq increases, the motor torque also increases.

[0094] At time t22, the motor current Iq reaches the target value. The torque control unit 511 stops the increase of the motor current Iq from time t22 when the motor current Iq reaches the target value. The increase of the motor torque also stops after time t22.

[0095] As described above, the connection state of the windings 21u, 22u, 21v, 22v, 21w, 22w of the motor 20 is switched from the series connection state to the parallel connection state, so that the performance of the motor 20 can be efficiently utilized and the speed can be electrically changed from the low rotation and high torque state to the high rotation and low torque state. In addition, the output torque of the motor 20 is reduced along with the switching of the connection state of the windings 21u, 22u, 21v, 22v, 21w, 22w of the motor 20, so that the driver can be given the same speed change feeling as a mechanical transmission.

[0096] The first target value Th1 is, for example, 0 A. When the connection state is switched while current is flowing in the windings 21u, 22u, 21v, 22v, 21w, 22w, a torque shock is generated due to a sudden change in current of the windings 21u, 22u, 21v, 22v, 21w, 22w, which are inductive loads. In addition, damage to the relays 111, 112, 113 due to surges is also generated. By setting the first target value Th1 to 0 A, the above-mentioned torque shock and damage to the relays 111, 112, 113 due to surges can be suppressed.

[0097] For example, when an electric downshift is instructed while the rotation speed of the motor 20 is increasing, that is, the vehicle is accelerating, the torque control unit 511 reduces the output torque of the motor 20 by reducing the AC current output from the power converter 30 at the second speed change timing. After the AC current output from the power converter 30 is reduced to or below the first target value, the switching control unit 512 causes the winding switching device 100 to switch the connection state of the windings 21u, 22u, 21v, 22v, 21w, and 22w of the motor 20 from the parallel connection state to the series connection state. The second speed change timing is the timing when the electric downshift is instructed.

[0098] Since the connection state of the windings 21u, 22u, 21v, 22v, 21w, 22w of the motor 20 is switched from the parallel connection state to the series connection state, the performance of the motor 20 can be efficiently utilized and the speed can be electrically changed from the high rotation and low torque state to the low rotation and high torque state. In addition, the output torque of the motor 20 increases with the switching of the connection state of the windings 21u, 22u, 21v, 22v, 21w, 22w of the motor 20, so that the driver can be given the same speed change feeling as a mechanical transmission.

[0099] For example, when an electric downshift is instructed when the motor 20 is performing regenerative braking, the torque control unit 511 increases the output torque of the motor 20 by increasing the AC current output from the power converter 30 at the second speed change timing. During regenerative braking, a torque for braking the vehicle, i.e., a negative torque, is generated, and the output torque of the motor 20 increases (approaches 0), thereby reducing the braking force. After the AC current output from the power converter 30 increases to or above the second target value, the switching control unit 512 causes the winding switching device 100 to switch the connection state of the windings 21u, 22u, 21v, 22v, 21w, and 22w of the motor 20 from the parallel connection state to the series connection state.

[0100] As described above, the connection state of the windings 21u, 22u, 21v, 22v, 21w, and 22w of the motor 20 is switched from the parallel connection state to the series connection state, so that the performance of the motor 20 can be efficiently utilized and the speed can be electrically changed from the high rotation and low torque state to the low rotation and high torque state. The regeneration amount of the motor 20 is higher in the low rotation and high torque state than in the high rotation and low torque state. Therefore, by electrically downshifting, the regenerative braking force can be increased, and the driver can be given the same deceleration feeling as engine braking. Moreover, with the switching of the connection state of the windings 21u, 22u, 21v, 22v, 21w, and 22w of the motor 20, the negative output torque of the motor 20 is reduced (the absolute value of the output torque increases), so the driver can be given the same speed change feeling as a mechanical transmission.

[0101] The torque control unit 511 can increase the motor current Iq in a ramp shape during electric downshifting, decrease the motor current Iq in a ramp shape during electric upshifting, and increase the motor current Iq in a ramp shape during electric downshifting, thereby providing the driver with a natural shifting feeling.

[0102] The second target value Th2 is, for example, 0 A. This can suppress torque shock caused by a sudden change in current of the windings 21u, 22u, 21v, 22v, 21w, and 22w and damage to the relays 111, 112, and 113 caused by surges.

[0103] For example, when an electric upshift is instructed while the motor 20 is performing regenerative braking, the torque control unit 511 increases the output torque of the motor 20 by increasing the AC current output from the power converter 30 at the first speed change timing. After the AC current output from the power converter 30 increases to a second target value or more, the switching control unit 512 causes the winding switching device 100 to switch the connection state of the windings 21u, 22u, 21v, 22v, 21w, and 22w of the motor 20 from the series connection state to the parallel connection state.

[0104] Since the connection state of the windings 21u, 22u, 21v, 22v, 21w, 22w of the motor 20 is switched from the series connection state to the parallel connection state, the performance of the motor 20 can be efficiently utilized and the speed can be electrically changed from the low rotation and high torque state to the high rotation and low torque state. By electrically upshifting, the regenerative braking force can be reduced, and the driver can be given the same deceleration feeling as engine braking. Moreover, with the switching of the connection state of the windings 21u, 22u, 21v, 22v, 21w, 22w of the motor 20, the negative output torque of the motor 20 increases (the absolute value of the output torque decreases), so the driver can be given the same speed change feeling as a mechanical transmission.

[0105] [1-4. Operation of the winding switching system]

[0106] Next, the operation of the winding switching device 100 will be described. The control device 50 executes the electric upshift process and the electric downshift process by causing the processor 501 to execute the motor control program 510 .

[0107] Figure 5 1 is a flowchart showing an example of the electric upshift process performed by the control device of the first embodiment. In this example, it is assumed that the windings 21u, 22u, 21v, 22v, 21w, and 22w of the motor 20 are connected in series at the start of the electric upshift process.

[0108] When the driver wants to perform an electric upshift of the vehicle, the driver operates the shift indicator 90 to input an electric upshift instruction to the vehicle. The processor 501 receives the electric upshift instruction (step S101).

[0109] The processor 501 refers to the detection signal of the torque sensor 202 to determine whether the motor torque is positive, that is, whether the motor 20 generates a torque for accelerating or maintaining the speed of the vehicle (hereinafter referred to as “acceleration torque”) (step S102 ).

[0110] When the motor torque is positive (YES in step S102 ), processor 501 outputs an instruction to reduce motor current Iq to power converter 30 (step S103 ). Thus, reduction of motor current Iq starts.

[0111] The processor 501 obtains the current value of the motor current Iq from the detection signals of the current sensors 33u, 33v, and 33w, and determines whether the motor current Iq is equal to or less than the first target value Th1 (step S104).

[0112] When the motor current Iq is greater than the first target value Th1 (No in step S104), the processor 501 executes step S104 again. When the motor current Iq is less than the first target value Th1 (Yes in step S104), the processor 501 outputs an instruction to stop the reduction of the motor current Iq to the power converter 30 (step S105). As a result, the reduction of the motor current Iq stops.

[0113] The processor 501 outputs an instruction to switch the connection state of the windings 21u, 22u, 21v, 22v, 21w, 22w of the motor 20 from the series connection state to the parallel connection state to the winding switching device 100 (step S106). As a result, during the period when the motor current Iq is less than the first target value Th1, the connection state of the windings 21u, 22u, 21v, 22v, 21w, 22w is switched from the series connection state to the parallel connection state, and an electric upshift is performed.

[0114] After outputting an instruction to switch the connection state of windings 21u, 22u, 21v, 22v, 21w, 22w of motor 20, processor 501 outputs an instruction to increase motor current Iq to power converter 30 (step S107). Thus, increase of motor current Iq starts.

[0115] When the motor current reaches the target value determined based on the target torque in the parallel connection state of the windings 21u, 22u, 21v, 22v, 21w, and 22w, the processor 501 outputs an instruction to stop the increase of the motor current Iq to the power converter 30 (step S108). As a result, the increase of the motor current Iq stops. The above ends the electric upshift process when the motor torque is positive.

[0116] When the motor torque is negative (No in step S102), the motor 20 performs regenerative braking. The power converter 30 functions as a DC / AC converter, and converts the AC current output from the motor 20 into a DC current. The converted DC current is output to the battery 40 and stored. In this case, the processor 501 outputs an instruction to increase the motor current Iq to the power converter 30 (step S109). Thus, the increase of the motor current Iq starts.

[0117] The processor 501 obtains the current value of the motor current Iq from the detection signals of the current sensors 33u, 33v, and 33w, and determines whether the motor current Iq is equal to or greater than the second target value Th2 (step S110).

[0118] When the motor current Iq is less than the second target value Th2 (No in step S110), the processor 501 executes step S110 again. When the motor current Iq is greater than the second target value Th2 (Yes in step S110), the processor 501 outputs an instruction to stop the increase of the motor current Iq to the power converter 30 (step S111). As a result, the increase of the motor current Iq stops.

[0119] The processor 501 outputs an instruction to switch the connection state of the windings 21u, 22u, 21v, 22v, 21w, 22w of the motor 20 from the series connection state to the parallel connection state to the winding switching device 100 (step S112). As a result, while the motor current Iq is greater than the second target value Th2, the connection state of the windings 21u, 22u, 21v, 22v, 21w, 22w is switched from the series connection state to the parallel connection state, and an electric upshift is performed.

[0120] After outputting an instruction to switch the connection state of windings 21u, 22u, 21v, 22v, 21w, 22w of motor 20, processor 501 outputs an instruction to reduce motor current Iq to power converter 30 (step S112). Thus, reduction of motor current Iq starts.

[0121] When the motor current reaches the target value determined based on the target torque in the parallel connection state of the windings 21u, 22u, 21v, 22v, 21w, and 22w, the processor 501 outputs an instruction to stop the reduction of the motor current Iq to the power converter 30 (step S113). As a result, the reduction of the motor current Iq stops. The above ends the electric upshift process when the motor torque is negative.

[0122] Figure 6 1 is a flowchart showing an example of the electric downshift process performed by the control device of Embodiment 1. In this example, it is assumed that the windings 21u, 22u, 21v, 22v, 21w, and 22w of the motor 20 are connected in parallel at the start of the electric downshift process.

[0123] When the driver wants to perform an electric downshift of the vehicle, the driver operates the shift indicator 90 to input an electric downshift instruction to the vehicle. The processor 501 receives the electric downshift instruction (step S201).

[0124] The processor 501 refers to the detection signal of the torque sensor 202 to determine whether the motor torque is positive, that is, whether the motor 20 generates an acceleration torque (step S202 ).

[0125] When the motor torque is positive (YES in step S202 ), processor 501 outputs an instruction to reduce motor current Iq to power converter 30 (step S203 ). Thus, reduction of motor current Iq starts.

[0126] The processor 501 obtains the current value of the motor current Iq from the detection signals of the current sensors 33u, 33v, and 33w, and determines whether the motor current Iq is equal to or less than the first target value Th1 (step S204).

[0127] When the motor current Iq is greater than the first target value Th1 (No in step S204), the processor 501 executes step S204 again. When the motor current Iq is less than the first target value Th1 (Yes in step S204), the processor 501 outputs an instruction to stop the reduction of the motor current Iq to the power converter 30 (step S205). As a result, the reduction of the motor current Iq stops.

[0128] The processor 501 outputs an instruction to switch the connection state of the windings 21u, 22u, 21v, 22v, 21w, 22w of the motor 20 from the parallel connection state to the series connection state to the winding switching device 100 (step S206). As a result, during the period when the motor current Iq is less than the first target value Th1, the connection state of the windings 21u, 22u, 21v, 22v, 21w, 22w is switched from the parallel connection state to the series connection state, and an electric downshift is performed.

[0129] After outputting an instruction to switch the connection state of windings 21u, 22u, 21v, 22v, 21w, 22w of motor 20, processor 501 outputs an instruction to increase motor current Iq to power converter 30 (step S207). Thus, increase of motor current Iq starts.

[0130] When the motor current reaches the target value determined based on the target torque in the parallel connection state of the windings 21u, 22u, 21v, 22v, 21w, and 22w, the processor 501 outputs an instruction to stop the increase of the motor current Iq to the power converter 30 (step S208). As a result, the increase of the motor current Iq stops. The above ends the electric downshift processing when the motor torque is positive.

[0131] When the motor torque is negative (No in step S202 ), the motor 20 performs regenerative braking. In this case, the processor 501 outputs an instruction to increase the motor current Iq to the power converter 30 (step S209 ). Thus, the increase of the motor current Iq starts.

[0132] The processor 501 obtains the current value of the motor current Iq from the detection signals of the current sensors 33u, 33v, and 33w, and determines whether the motor current Iq is equal to or greater than the second target value Th2 (step S210).

[0133] When the motor current Iq is less than the second target value Th2 (No in step S210), the processor 501 executes step S210 again. When the motor current Iq is greater than the second target value Th2 (Yes in step S210), the processor 501 outputs an instruction to stop the increase of the motor current Iq to the power converter 30 (step S211). As a result, the increase of the motor current Iq stops.

[0134] The processor 501 outputs an instruction to switch the connection state of the windings 21u, 22u, 21v, 22v, 21w, 22w of the motor 20 from the parallel connection state to the series connection state to the winding switching device 100 (step S212). As a result, while the motor current Iq is greater than the second target value Th2, the connection state of the windings 21u, 22u, 21v, 22v, 21w, 22w is switched from the parallel connection state to the series connection state, and an electric downshift is performed.

[0135] After outputting an instruction to switch the connection state of windings 21u, 22u, 21v, 22v, 21w, 22w of motor 20, processor 501 outputs an instruction to reduce motor current Iq to power converter 30 (step S212). Thus, reduction of motor current Iq starts.

[0136] When the motor current reaches the target value determined based on the target torque in the parallel connection state of the windings 21u, 22u, 21v, 22v, 21w, and 22w, the processor 501 outputs an instruction to stop the reduction of the motor current Iq to the power converter 30 (step S213). As a result, the reduction of the motor current Iq stops. The above ends the electric downshift process when the motor torque is negative.

[0137] [2. Second Embodiment]

[0138] The winding switching device according to the second embodiment switches the connection state of the plurality of windings of the motor between a fully connected state in which all of the plurality of windings are connected and a partially connected state in which a part of the plurality of windings are connected.

[0139] Figure 7 2 is a circuit diagram showing an example of the structure of the winding switching device of the second embodiment. The motor 20A includes a plurality of windings 24u, 25u, 24v, 25v, 24w, and 25w. The windings 24u and 25u correspond to U, the windings 24v and 25v correspond to V, and the windings 24w and 25w correspond to W. However, the number of windings of each phase is not limited to two, and may be three or more.

[0140] The winding switching device 100A switches the connection state of the windings 24u, 25u, 24v, 25v, 24w, 25w between a full connection state and a partial connection state for each phase. The winding switching device 100A includes control circuits 103u, 103v, 103w and switching circuits 140u, 140v, 140w.

[0141] The switching circuits 140u, 140v, and 140w switch the connection state of the windings 24u, 25u, 24v, 25v, 24w, and 25w between a fully connected state and a partially connected state. The fully connected state is an example of the first connected state, and the partially connected state is an example of the second connected state.

[0142] The power line 35u is connected to one end of the winding 24u. The other end of the winding 24u and one end of the winding 25u are connected to each other, and the power line 241u extends from the middle point between the winding 24u and the winding 25u. The power line 241u branches into power lines 242u and 243w. The power line 251u extends from the other end of the winding 25u. The power line 251u branches into power lines 252u and 253w.

[0143] The power line 35v is connected to one end of the winding 24v. The other end of the winding 24v and one end of the winding 25v are connected to each other, and the power line 241v extends from the middle point between the winding 24v and the winding 25v. The power line 241v branches into power lines 242v and 243u. The power line 251v extends from the other end of the winding 25v. The power line 251v branches into power lines 252v and 253u.

[0144] The power line 35w is connected to one end of the winding 24w. The other end of the winding 24w and one end of the winding 25w are connected to each other, and the power line 241w extends from the middle point between the winding 24w and the winding 25w. The power line 241w branches into power lines 242w and 243v. The power line 251w extends from the other end of the winding 25w. The power line 251w branches into power lines 252w and 253v.

[0145] 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.

[0146] In the switching circuit 140u, the first terminal of the semiconductor relay 141u is connected to the power line 242u, and the second terminal is connected to the power line 243u. The first terminal of the semiconductor relay 142u is connected to the power line 252u, and the second terminal is connected to the power line 253u. The connection relationship of the switching circuits 140v and 140w is the same as that of the switching circuit 140u, so the description is omitted.

[0147] When the semiconductor relays 141u, 141v, 141w are in the off state and the semiconductor relays 142u, 142v, 142w are in the on state, the windings 24u, 25u, 24v, 25v, 24w, 25w are in the fully connected state. When the semiconductor relays 141u, 141v, 141w are in the on state and the semiconductor relays 142u, 142v, 142w are in the off state, the windings 24u, 24v, 24w, 25w are in the partially connected state in which only the windings 24u, 24v, 24w are connected.

[0148] The other structures of the winding switching device 100A according to the second embodiment are the same as those of the winding switching device 100 according to the first embodiment, and therefore the same components are denoted by the same reference numerals and their description is omitted.

[0149] In the second embodiment, an electric upshift is performed by switching the connection state of the windings 24u, 25u, 24v, 25v, 24w, 25w of the motor 20 from a fully connected state to a partially connected state. An electric downshift is performed by switching the connection state of the windings 24u, 25u, 24v, 25v, 24w, 25w of the motor 20 from a partially connected state to a fully connected state.

[0150] [3. Third embodiment]

[0151] In the third embodiment, the torque control unit 511 changes the effective current of the AC current output from the power converter 30 in steps based on the speed change timing.

[0152] Figure 8 1 is a time chart showing an example of the switching timing of the windings 21u, 22u, 21v, 22v, 21w, and 22w of the motor 20 in the winding switching system of the third embodiment. It should be noted that the structure of the winding switching system of the third embodiment is the same as the structure of the winding switching system 10 of the first embodiment, so the same components are marked with the same reference numerals and the description is omitted.

[0153] exist Figure 8 An example of the speed change indication, motor current, motor torque, and timing of on / off switching of semiconductor relays 111, 112, 113 when the connection state of windings 21u, 22u, 21v, 22v, 21w, 22w of motor 20 is switched from a series connection state to a parallel connection state is shown.

[0154] At time t1, a speed change instruction (electric upshift instruction) is input to the control device 50. At time t1, the torque control unit 511 reduces the motor current Iq in a stepwise manner to a value below the first target value Th1. As the motor current Iq decreases, the motor torque also decreases in a stepwise manner. After time t1, the motor current Iq is maintained at the first target value Th1.

[0155] The switching control unit 512 switches the connection state of the windings 21u, 22u, 21v, 22v, 21w, and 22w from the series connection state to the parallel connection state at a timing after time t1. Figure 8 In the example, at time t01 later than time t1, relays 111 and 113 are switched from the on state to the off state, and at time t02 later than time t01, relay 112 is switched from the off state to the on state. During the period between time t01 and time t02, relays 111, 112, and 113 are all in the off state. Thus, when the connection state of windings 21u, 22u, 21v, 22v, 21w, and 22w is switched, relays 111, 112, and 113 are prevented from all becoming on.

[0156] At time t2 later than time t02, the torque control unit 511 increases the motor current Iq in a step-like manner. The target value of the motor current Iq at this time is determined based on the target torque in the parallel connection state of the windings 21u, 22u, 21v, 22v, 21w, and 22w. The target torque is determined based on the rotation speed of the motor 20, the output torque of the motor 20, the depression amount of the brake pedal 70 (brake indication amount), and the depression amount of the accelerator pedal 80 (acceleration indication amount). As the motor current Iq increases, the motor torque also increases in a step-like manner.

[0157] As the connection states of the windings 21u, 22u, 21v, 22v, 21w, and 22w of the motor 20 are switched, the output torque of the motor 20 decreases in a stepwise manner, thereby providing the driver with the same shifting feeling as a mechanical transmission.

[0158] [4. Fourth embodiment]

[0159] In the fourth embodiment, the torque control unit 511 changes the effective current of the AC current output from the power converter 30 in a curved manner based on the speed change timing.

[0160] Fig. 9 2 is a timing chart showing an example of the switching timing of the windings 21u, 22u, 21v, 22v, 21w, and 22w of the motor 20 in the winding switching system of the fourth embodiment. Fig. 9 An example of the speed change indication, motor current, motor torque, and timing of on / off switching of semiconductor relays 111, 112, 113 when the connection state of windings 21u, 22u, 21v, 22v, 21w, 22w of motor 20 is switched from a series connection state to a parallel connection state is shown.

[0161] At time t11, a speed change instruction (electric upshift instruction) is input to the control device 50. The torque control unit 511 starts to reduce the motor current Iq in a curve from time t11. Fig. 9 In the example shown, the slope of the decrease of the motor current Iq gradually increases from time t11 and becomes infinite at the midpoint between time t11 and time t12. Then, the slope of the decrease of the motor current Iq gradually decreases and becomes 0 (the decrease stops) at time t12.

[0162] At time t12, the motor current Iq reaches the first target value Th1. The torque control unit 511 stops the reduction of the motor current Iq from time t12 when the motor current Iq reaches the first target value Th1. That is, the motor current Iq is maintained at the first target value Th1 after time t12. The reduction of the motor torque also stops after time t12.

[0163] The switching control unit 512 switches the connection state of the windings 21u, 22u, 21v, 22v, 21w, and 22w from the series connection state to the parallel connection state at a timing after time t12. Fig. 9 In the example, at time t01 later than time t12, the relays 111 and 113 are switched from the on state to the off state, and at time t02 later than time t01, the relay 112 is switched from the off state to the on state. During the period between time t01 and time t02, the relays 111, 112, and 113 are all in the off state. Thus, when the connection states of the windings 21u, 22u, 21v, 22v, 21w, and 22w are switched, the relays 111, 112, and 113 are prevented from all becoming in the on state.

[0164] From time t21 later than time t02, the torque control unit 511 increases the motor current Iq. The target value of the motor current Iq at this time is determined based on the target torque in the parallel connection state of the windings 21u, 22u, 21v, 22v, 21w, and 22w. The target torque is determined based on the rotation speed of the motor 20, the output torque of the motor 20, the depression amount of the brake pedal 70 (the braking indication amount), and the depression amount of the accelerator pedal 80 (the acceleration indication amount). Fig. 9 In the example shown, the motor current Iq increases in a curve. As the motor current Iq increases, the motor torque also increases.

[0165] exist Fig. 9 In the example shown, the slope of the increase of the motor current Iq gradually increases from time t21, and becomes infinite at the midpoint between time t21 and time t22. Then, the slope of the increase of the motor current Iq gradually decreases, and becomes 0 (increase stops) at time t22.

[0166] At time t22, the motor current Iq reaches the target value. The torque control unit 511 stops the increase of the motor current Iq from time t22 when the motor current Iq reaches the target value. The increase of the motor torque also stops after time t22.

[0167] The output torque of the motor 20 decreases in a curve as the connection states of the windings 21u, 22u, 21v, 22v, 21w, 22w of the motor 20 are switched. In the fourth embodiment, the rapid change of the motor torque is suppressed, so the driver can feel the same shifting feeling as a mechanical transmission.

[0168] [5. Fifth embodiment]

[0169] In the fifth embodiment, the torque control unit 511 executes a pseudo speed change control process of decreasing and then increasing the AC current output from the power converter 30 at a pseudo speed change timing different from the timing of the electric upshift and the electric downshift (electric speed change timing).

[0170] Fig.10 1 is a time chart showing an example of a pseudo speed change control process in the winding switching system of the fifth embodiment. Fig.10 An example of the speed change indication, motor current, motor torque, and timing of on / off switching of semiconductor relays 111, 112, 113 when the connection state of windings 21u, 22u, 21v, 22v, 21w, 22w of motor 20 is switched from a series connection state to a parallel connection state is shown.

[0171] At time t31, a speed change instruction (pseudo speed change instruction) is input to the control device 50. The torque control unit 511 starts to reduce the motor current Iq from time t31. Fig.10 In the example shown, the motor current Iq decreases gradually in a ramp shape. As the motor current Iq decreases, the motor torque also decreases.

[0172] At time t32, the motor current Iq reaches the third target value Th1. The torque control unit 511 stops the reduction of the motor current Iq from time t32 when the motor current Iq reaches the first target value Th1. That is, the motor current Iq is maintained at the first target value Th1 after time t32. The reduction of the motor torque also stops after time t32.

[0173] The torque control unit 511 maintains the motor current Iq at the first target value Th1 during a constant period. During this period, the switching control unit 512 does not switch the connection state of the windings 21u, 22u, 21v, 22v, 21w, 22w. That is, the semiconductor relays 111 and 113 remain in the on state, and the semiconductor relay 112 remains in the off state.

[0174] From time t41 later than time t32, the torque control unit 511 increases the motor current Iq. That is, the torque control unit 511 increases the motor current Iq after maintaining the motor current Iq at the first target value Th1 for a constant period. It should be noted that the torque control unit 511 may increase the motor current Iq without providing a stop period after the motor current Iq decreases to below the first target value Th1.

[0175] The target value of the motor current Iq at this time is the same as the target value before the change of the motor current Iq. Fig.10 In the example shown, the motor current Iq increases in a ramp shape. As the motor current Iq increases, the motor torque also increases.

[0176] At time t42, the motor current Iq reaches the target value. The torque control unit 511 stops the increase of the motor current Iq from time t42 when the motor current Iq reaches the target value. The increase of the motor torque also stops after time t42.

[0177] Fig.11 This is a flowchart showing an example of pseudo speed change processing performed by the control device according to the fifth embodiment.

[0178] The driver operates the gear shift indicator 90 to input a gear shift instruction to the vehicle. The processor 501 receives the gear shift instruction (step S301).

[0179] The processor 501 refers to the detection signal of the torque sensor 202 to determine whether the motor torque is positive, that is, whether the motor 20 generates an acceleration torque (step S302 ).

[0180] When the motor torque is positive (YES in step S302 ), processor 501 outputs an instruction to reduce motor current Iq to power converter 30 (step S303 ). Thus, reduction of motor current Iq starts.

[0181] The processor 501 obtains the current value of the motor current Iq from the detection signals of the current sensors 33u, 33v, and 33w, and determines whether the motor current Iq is equal to or less than the first target value Th1 (step S304).

[0182] When the motor current Iq is greater than the first target value Th1 (No in step S304), the processor 501 executes step S304 again. When the motor current Iq is less than the first target value Th1 (Yes in step S304), the processor 501 outputs an instruction to stop the reduction of the motor current Iq to the power converter 30 (step S305). As a result, the reduction of the motor current Iq stops.

[0183] Processor 501 outputs an instruction to increase motor current Iq to power converter 30 without switching the connection state of windings 21u, 22u, 21v, 22v, 21w, 22w of motor 20 (step S306). Thus, increase of motor current Iq starts.

[0184] When the motor current Iq reaches the target value that is the same as the target value before the change of the motor current Iq, the processor 501 outputs an instruction to stop the increase of the motor current Iq to the power converter 30 (step S307). As a result, the increase of the motor current Iq stops. The above simulated speed change processing when the motor torque is positive ends.

[0185] When the motor torque is negative (No in step S302 ), the motor 20 performs regenerative braking. In this case, the processor 501 outputs an instruction to increase the motor current Iq to the power converter 30 (step S308 ). Thus, the increase of the motor current Iq starts.

[0186] The processor 501 obtains the current value of the motor current Iq from the detection signals of the current sensors 33u, 33v, and 33w, and determines whether the motor current Iq is equal to or greater than the second target value Th2 (step S309).

[0187] When the motor current Iq is less than the second target value Th2 (No in step S309), the processor 501 executes step S309 again. When the motor current Iq is greater than the second target value Th2 (Yes in step S309), the processor 501 outputs an instruction to stop the increase of the motor current Iq to the power converter 30 (step S310). As a result, the increase of the motor current Iq stops.

[0188] The processor 501 outputs an instruction to reduce the motor current Iq to the power converter 30 without switching the connection state of the windings 21u, 22u, 21v, 22v, 21w, and 22w of the motor 20 (step S311 ). Thus, the motor current Iq starts to be reduced.

[0189] When the motor current Iq reaches the same target value as the target value before the change of the motor current Iq, the processor 501 outputs an instruction to stop the reduction of the motor current Iq to the power converter 30 (step S312). As a result, the reduction of the motor current Iq stops. The above simulated speed change processing when the motor torque is negative ends.

[0190] As described above, the connection state of the windings 21u, 22u, 21v, 22v, 21w, and 22w of the motor 20 is not switched, and the output torque of the motor 20 changes according to the speed change instruction, so that the driver can be given a simulated speed change feeling without performing electric speed change.

[0191] By combining the above-mentioned simulated speed change processing with the electric speed change, the driver can feel the feeling of multi-speed change. For example, by performing the simulated speed change processing in the switching between the 1st gear and the 2nd gear, the switching between the 2nd gear and the 3rd gear, the switching between the 4th gear and the 5th gear, and the switching between the 5th gear and the 6th gear, and performing the electric speed change processing (electric upshift processing and electric downshift processing) in the switching between the 3rd gear and the 4th gear, the driver can feel the feeling of 6-speed change, and the electric speed change that effectively utilizes the performance of the motor can be performed in the switching between the 3rd gear and the 4th gear.

[0192] [6. Sixth Implementation Method]

[0193] Reference Figure 3 , the structure of the winding switching system of the sixth embodiment is described.

[0194] The winding switching device 100 has voltage sensors 34u, 34v, 34w for detecting the voltage in the windings 21u, 21v, 21w. In a specific example, the voltage sensor 34u is arranged between the power line 35u and the power line 212u, the voltage sensor 34v is arranged between the power line 35v and the power line 212v, and the voltage sensor 34w is arranged between the power line 35w and the power line 212w. The voltage sensors 34u, 34v, 34w are connected to the control device 50. The control device 50 can receive the detection values ​​of the voltage sensors 34u, 34v, 34w.

[0195] The other structures of the winding switching system of the sixth embodiment are the same as those of the winding switching system 10 of the first embodiment, and therefore the same components are denoted by the same reference numerals and their description is omitted.

[0196] Fig.12 1 is a functional block diagram showing an example of functions of the control device of the sixth embodiment. The control device 50A includes functions of a first determination unit 513 , a determination unit 514 , a prohibition unit 515 , and a second determination unit 516 in addition to functions of a torque control unit 511 and a switching control unit 512 .

[0197] The functions of the torque control unit 511 and the switching control unit 512 are the same as those in the first embodiment, and thus detailed descriptions thereof are omitted.

[0198] The first determination unit 513 determines the timing before the induced voltage generated in the windings 21u, 22u, 21v, 22v, 21w, 22w exceeds the output voltage of the battery 40 when the connection state of the plurality of windings 21u, 22u, 21v, 22v, 21w, 22w is in the series connection state as the first forced speed change timing. The first forced speed change timing is a timing for starting forced switching of the connection state of the windings 21u, 22u, 21v, 22v, 21w, 22w from the series connection state to the parallel connection state regardless of the presence or absence of a speed change instruction from the speed change indicator 90 or the automatic speed change control device.

[0199] An induced voltage corresponding to the rotation speed of the motor 20 is generated in the windings 21u, 22u, 21v, 22v, 21w, 22w. The power converter 30 can control the applied voltage of the windings 21u, 22u, 21v, 22v, 21w, 22w within the range of the output voltage of the battery 40. The polarity of the induced voltage of the windings 21u, 22u, 21v, 22v, 21w, 22w is opposite to the polarity of the applied voltage, so when the induced voltage exceeds the output voltage of the battery 40, the current in the windings 21, 22u, 21v, 22v, 21w, 22w cannot be made zero. Therefore, when the first target value Th1 is 0A, if the induced voltage exceeds the output voltage of the battery 40, the motor current Iq cannot be reduced to the first target value Th1 in the electric upshift process.

[0200] Therefore, in the sixth embodiment, the first determination unit 513 monitors the induced voltage generated in the windings 21u, 22u, 21v, 22v, 21w, and 22w in the series connection state, and determines the timing before the induced voltage shifts from a range below the output voltage of the battery 40 to a range exceeding the output voltage as the first forced speed change timing.

[0201] The torque control unit 511 changes the output torque of the motor 20 by changing the AC current output from the power converter 30 at the first forced speed change timing determined by the first determination unit 513. After the AC current is changed, the switching control unit 512 causes the winding switching device 100 to switch the connection state of the windings 21u, 22u, 21v, 22v, 21w, and 22w from the series connection state to the parallel connection state.

[0202] In a specific example, the first determination unit 513 generates an electric upshift instruction when determining the first forced shift timing, thereby starting the electric upshift process.

[0203] In a specific example, the first determination unit 513 can determine the timing when the physical quantity related to the induced voltage exceeds the first threshold value corresponding to the output voltage of the battery 40 as the first forced speed change timing. The physical quantity is, for example, the rotation speed of the motor 20. In this case, the first determination unit 513 can obtain the detection value from the rotation sensor 201. Another example of the physical quantity is the voltage in the windings 21u, 21v, and 21w. In this case, the detection values ​​can be obtained from the voltage sensors 34u, 34v, and 34w, respectively. The physical quantity can also be the current flowing in the windings 21u, 22u, 21v, 22v, 21w, and 22w, and can also be the output torque of the motor 20. In the following description, the physical quantity is set to the rotation speed of the motor 20.

[0204] When the connection state of multiple windings 21u, 22u, 21v, 22v, 21w, and 22w is in a parallel connection state, the determination unit 514 determines whether the induced voltage after the connection state of the windings 21u, 22u, 21v, 22v, 21w, and 22w is switched from a parallel connection state to a series connection state exceeds the output voltage of the battery.

[0205] In a specific example, the determination unit 514 can determine whether the physical quantity related to the induced voltage in the series connection state is less than the second threshold value corresponding to the output voltage of the battery 40. More specifically, the determination unit 514 obtains the rotation speed of the motor 20. According to the rotation speed of the motor 20, the induced voltage when the windings 21u, 22u, 21v, 22v, 21w, and 22w are in a series connection state can be determined. The second threshold value is, for example, the rotation speed of the motor 20 when the induced voltage when the windings 21u, 22u, 21v, 22v, 21w, and 22w are in a series connection state is equal to the output voltage of the battery 40. However, the second threshold value is not limited to this. For example, the second threshold value may also be the rotation speed of the motor 20 when the induced voltage when the windings 21u, 22u, 21v, 22v, 21w, and 22w are in a series connection state is lower than the output voltage of the battery 40 by a predetermined margin.

[0206] The prohibition unit 515 prohibits the switching control of the connection state of the windings 21u, 22u, 21v, 22v, 21w, 22w by the switching control unit 512 when the determination unit 514 determines that the induced voltage exceeds the output voltage of the battery 40. In a specific example, the prohibition unit 515 prohibits the switching control of the connection state of the windings 21u, 22u, 21v, 22v, 21w, 22w by the switching control unit 512 during the period when the rotation speed of the motor 20 exceeds the second threshold value. In this way, it is avoided that the connection state of the windings 21u, 22u, 21v, 22v, 21w, 22w is switched from the parallel connection state to the series connection state to prevent the induced voltage from exceeding the output voltage of the battery 40.

[0207] When the rotation speed of the motor 20 becomes equal to or lower than the second threshold, the prohibition unit 515 cancels the prohibition of the switching control of the connection state of the windings 21u, 22u, 21v, 22v, 21w, and 22w by the switching control unit 512.

[0208] The second determination unit 516 determines the timing after the induced voltage after the connection state of the windings 21u, 22u, 21v, 22v, 21w, 22w is switched from the parallel connection state to the series connection state as the second forced speed change timing. The second forced speed change timing is a timing for starting forced switching of the connection state of the windings 21u, 22u, 21v, 22v, 21w, 22w from the parallel connection state to the series connection state regardless of the presence or absence of a speed change instruction from the speed change indicator 90 or the automatic speed change control device.

[0209] In the series connection state, the regenerated power can be recovered more efficiently than in the parallel connection state. Moreover, in the series connection state, the higher the speed of the motor 20, the greater the regeneration amount. Therefore, for example, when the vehicle is decelerating in the parallel connection state, in order to efficiently recover the regenerated power, it is preferred to perform electric downshifting at a timing when the speed of the motor 20 is as high as possible within a range where the induced voltage after switching to the series connection state is less than the output voltage of the battery 40.

[0210] The second determination unit 516 estimates the induced voltage generated in the windings 21u, 22u, 21v, 22v, 21w, and 22w in the series connection state, and determines the timing when the induced voltage shifts from a range exceeding the output voltage of the battery 40 to a range below the output voltage of the battery 40 as the second forced speed change timing.

[0211] The torque control unit 511 changes the output torque of the motor 20 by changing the AC current output from the power converter 30 at the second forced speed change timing determined by the second determination unit 516. After the AC current is changed, the switching control unit 512 causes the winding switching device 100 to switch the connection state of the windings 21u, 22u, 21v, 22v, 21w, and 22w from the parallel connection state to the series connection state.

[0212] In a specific example, the second determination unit 516 generates an electric downshift instruction when determining the second forced shift timing, thereby starting the electric downshift process.

[0213] In a specific example, the second determination unit 516 can determine as the second forced shift timing the timing when the physical quantity related to the induced voltage becomes less than a second threshold value corresponding to the output voltage of the battery 40. For example, the second determination unit 516 determines as the second forced shift timing the timing when the rotation speed of the motor 20 becomes less than the second threshold value.

[0214] The operation of the winding switching system according to the sixth embodiment will be described below. The control device 50A executes the following forced upshift determination process and forced downshift determination process.

[0215] Fig.13 1 is a flowchart showing an example of a forced upshift determination process performed by the control device of the sixth embodiment. In this example, it is assumed that the windings 21u, 22u, 21v, 22v, 21w, and 22w of the motor 20 are connected in series.

[0216] The rotation sensor 201 detects the rotation speed of the output shaft of the motor 20 and outputs the detected rotation speed. For example, the rotation sensor 201 detects the rotation speed at a constant period and outputs the detection result. The control device 50A receives the detection value of the rotation speed output from the rotation sensor 201 (step S401).

[0217] The processor 501 compares the obtained rotation speed R with the first threshold Th1_R to determine whether the rotation speed R exceeds the first threshold Th1_R (step S402). The first threshold Th1_R is a value lower than the rotation speed of the motor 20 by a predetermined margin when the induced voltage generated in the windings 21u, 22u, 21v, 22v, 21w, and 22w in the series connection state is consistent with the output voltage of the battery 40.

[0218] When the rotation speed R is less than or equal to the first threshold value Th1_R (NO in step S402 ), the processor 501 returns to step S401 .

[0219] When the rotation speed R exceeds the first threshold value Th1_R (YES in step S402 ), the processor 501 determines the timing as the first forced shift timing. The processor 501 generates an electric upshift instruction (step S403 ).

[0220] Next, the processor 501 starts the electric upshift process (step S404). Thus, after the motor current Iq decreases, the connection state of the windings 21u, 22u, 21v, 22v, 21w, 22w is switched from the series connection state to the parallel connection state. The forced upshift determination process ends as described above.

[0221] Fig.14 2 is a flowchart showing an example of forced downshift determination processing performed by the control device of the sixth embodiment. In this example, it is assumed that the windings 21u, 22u, 21v, 22v, 21w, and 22w of the motor 20 are connected in parallel.

[0222] The control device 50A receives the detection value of the rotation speed output from the rotation sensor 201 (step S501 ).

[0223] The processor 501 compares the obtained rotational speed R with the second threshold value Th2_R to determine whether the rotational speed R is below the second threshold value Th2_R (step S502). The second threshold value Th2_R is a value that is lower than the rotational speed of the motor 20 by a predetermined margin when the induced voltage generated in the windings 21u, 22u, 21v, 22v, 21w, and 22w in the series connection state is consistent with the output voltage of the battery 40. The second threshold value Th2_R can be the same value as the first threshold value Th1_R, or a different value. For example, the second threshold value Th2_R is a value lower than the first threshold value Th1_R. In this way, it is possible to suppress the rotational speed R from exceeding the first threshold value Th1_R shortly after the electric downshift is completed and a forced upshift is performed.

[0224] When the speed R is greater than the second threshold value Th2_R (No in step S502), the processor 501 prohibits electric downshifting (step S503). Thus, even if, for example, the driver gives an electric downshift instruction, the electric downshift is not performed. When the electric downshift is prohibited, the processor 501 returns to step S501.

[0225] When the speed R is less than the second threshold value Th2_R (Yes in step S502), the processor 501 determines the timing as the second forced shift timing. In this case, if the electric downshift is prohibited, the processor 501 cancels the prohibition of the electric downshift. When determining the second forced shift timing, the processor 501 generates an electric downshift instruction (step S504).

[0226] Next, the processor 501 starts the electric downshift process (step S505). Thus, after the motor current Iq approaches zero, the connection state of the windings 21u, 22u, 21v, 22v, 21w, 22w is switched from the parallel connection state to the series connection state. The forced downshift determination process ends as described above.

[0227] [7. Supplementary Note]

[0228] The embodiments disclosed this time are all examples and are not restrictive. The scope of rights of the present invention is indicated by the claims rather than the above-described embodiments, and includes all modifications within the meaning and scope equivalent to the claims.

[0229] Description of Reference Numerals

[0230] 10 Winding switching system

[0231] 20 Motor (drive motor)

[0232] 21u, 22u, 21v, 22v, 21w, 22w winding

[0233] 23 Neutral point

[0234] 25 Power Lines

[0235] 30 Power Converter

[0236] 31u, 32u, 31v, 32v, 31w, 32w switch

[0237] 33u, 33v, 33w current sensor

[0238] 34u, 34v, 34w voltage sensors

[0239] 35u, 35v, 35w power line

[0240] 40 Batteries

[0241] 50, 50A control device

[0242] 501 Processor

[0243] 502 Non-volatile memory

[0244] 503 Volatile Memory

[0245] 504 Interface (I / F)

[0246] 510 Motor Control Program

[0247] 511 Torque Control Unit

[0248] 512 Switching control unit

[0249] 513 First Decision Department

[0250] 514 Judgment Department

[0251] 515 Prohibition Department

[0252] 516 Second Decision Department

[0253] 60 Wheels

[0254] 70 Brake pedal

[0255] 71 Sensors

[0256] 80 Accelerator pedal

[0257] 81 Sensors

[0258] 90 Speed ​​indicator

[0259] 100 Winding switching device

[0260] 103u, 103v, 103w control circuit

[0261] 104u, 104v, 104w switching circuit

[0262] 111u, 112u, 113u, 111v, 112v, 113v, 111w, 112w, 113w semiconductor relays

[0263] 201 Rotation Sensor

[0264] 202 Torque sensor

[0265] 212u, 221u, 222u Power Line

[0266] 20A Motor

[0267] 24u, 25u, 24v, 25v, 24w, 25w winding

[0268] 100A Winding Switching Device

[0269] 140u, 140v, 140w switching circuit

[0270] 141u, 142u, 141v, 142v, 141w, 142w semiconductor relays

[0271] 241u, 242u, 243u, 251u, 252u, 253u, 241v, 242v, 243v, 251v, 252v, 253v, 241w, 242w, 243w, 251w, 252w, 253w power line

Claims

1. A winding switching system for a motor for a vehicle, comprising: A drive motor drives the wheels of the vehicle; A control device for controlling the drive motor; a power converter that converts direct current power output from the battery into alternating current power and supplies the alternating current power to the drive motor; and A winding switching device switches the connection state of the plurality of windings in the drive motor between a first connection state and a second connection state, The control device comprises: a torque control unit that changes the output torque of the drive motor by changing the AC current output from the power converter at a predetermined speed change timing of the vehicle; and The switching control unit switches the winding switching device from the first connection state to the second connection state after the alternating current changes.

2. The winding switching system for a vehicle motor according to claim 1, wherein: The torque control unit reduces the output torque of the drive motor by reducing the AC current output from the power converter at a first speed change timing. The switching control unit switches the winding switching device from the first connection state to the second connection state after the AC current decreases to a first target value or less.

3. The winding switching system for a vehicle motor according to claim 2, wherein: The torque control unit reduces the output torque of the drive motor by reducing the AC current output from the power converter at a second speed change timing different from the first speed change timing. The switching control unit switches the winding switching device from the second connection state to the first connection state after the AC current decreases to be equal to or less than the first target value.

4. The winding switching system for a vehicle motor according to claim 1, wherein: The torque control unit increases the output torque of the drive motor by increasing the AC current output from the power converter at a first speed change timing. The switching control unit switches the winding switching device from the first connection state to the second connection state after the AC current increases to a second target value or more.

5. The winding switching system for a vehicle motor according to claim 4, wherein: The torque control unit increases the output torque of the drive motor by increasing the AC current output from the power converter at a second speed change timing different from the first speed change timing, The switching control unit switches the winding switching device from the second connection state to the first connection state after the AC current increases to a second target value or more.

6. The winding switching system for a vehicle motor according to any one of claims 1 to 5, wherein: The second connection state is a connection state for the drive motor to output a torque lower than that of the first connection state at the same rotation speed.

7. The winding switching system for a vehicle motor according to claim 6, wherein: The control device further includes a first determination unit that determines a timing before an induced voltage generated in the winding exceeds an output voltage of the battery when the connection state of the plurality of windings is the first connection state as a first forced speed change timing. The torque control unit changes the output torque of the drive motor by changing the AC current output from the power converter at the first forced speed change timing determined by the first determination unit. The switching control unit switches the winding switching device from the first connection state to the second connection state after the alternating current changes.

8. The winding switching system for a vehicle motor according to claim 7, wherein: The first determination unit determines, as the first forced speed change timing, a timing at which a physical quantity related to the induced voltage exceeds a first threshold value corresponding to an output voltage of the battery.

9. The winding switching system for a vehicle motor according to claim 8, wherein: The physical quantity is one of a voltage in the winding, a rotation speed of the drive motor, a current flowing in the winding, and an output torque of the drive motor.

10. The winding switching system for a vehicle motor according to any one of claims 7 to 9, wherein: The control device also includes: a determination unit that determines, when the connection state of the plurality of windings is the second connection state, whether the induced voltage after the connection state of the windings is switched from the second connection state to the first connection state exceeds the output voltage of the battery; and The prohibition unit prohibits the switching control of the connection state of the winding by the switching control unit when the determination unit determines that the induced voltage exceeds the output voltage of the battery.

11. The winding switching system for a vehicle motor according to any one of claims 7 to 10, wherein: The control device further includes a second determination unit that determines, as a second forced speed change timing, a timing after the induced voltage becomes less than the output voltage of the battery after the connection state of the windings is switched from the second connection state to the first connection state when the connection state of the plurality of windings is the second connection state, The torque control unit changes the output torque of the drive motor by changing the AC current output from the power converter at the second forced speed change timing determined by the second determination unit. The switching control unit switches the winding switching device from the second connection state to the first connection state after the alternating current changes.

12. The winding switching system for a vehicle motor according to claim 11, wherein: The second determination unit determines, as the second forced speed change timing, a timing at which a physical quantity related to the induced voltage becomes equal to or less than a second threshold value corresponding to an output voltage of the battery.

13. The winding switching system for a vehicle motor according to any one of claims 1 to 12, wherein: The winding switching system further includes an input device for receiving a speed change instruction from a driver. The gear shift timing is a timing at which the input device receives the gear shift instruction from the driver.

14. The winding switching system for a vehicle motor according to any one of claims 1 to 12, wherein: The speed change timing is a timing determined based on the rotation speed and output torque of the drive motor, an acceleration instruction amount in the vehicle, and a braking instruction amount in the vehicle.

15. The winding switching system for a vehicle motor according to any one of claims 1 to 14, wherein: The torque control unit gradually decreases or increases the effective current of the AC current output from the power converter starting from the speed change timing.

16. The winding switching system for a vehicle motor according to claim 15, wherein: The torque control unit changes the effective current in a ramp shape starting from the speed change timing.

17. The winding switching system for a vehicle motor according to any one of claims 1 to 14, wherein: The torque control unit changes the effective current of the AC current output from the power converter in a stepwise manner based on the speed change timing.

18. The winding switching system for a vehicle motor according to any one of claims 1 to 17, wherein: The torque control unit executes a pseudo speed change control process of decreasing the AC current output from the power converter at a pseudo speed change timing different from the speed change timing and then increasing the AC current.

19. A control device for controlling a drive motor for driving wheels of a vehicle, the control device comprising: a torque control unit that changes the output torque of the drive motor by changing an AC current output from a power converter at a predetermined speed change timing of the vehicle, the power converter converting DC power output from a battery into AC power and supplying the AC power to the drive motor; and The switching control unit switches a winding switching device that switches connection states of a plurality of windings in the drive motor from a first connection state to a second connection state after the alternating current changes.

20. A method for controlling a motor for a vehicle, the method being executed by a control device for controlling a drive motor for driving wheels of a vehicle, the method comprising the following steps: The output torque of the drive motor is changed by changing the AC current output from the power converter at a predetermined speed change timing of the vehicle, wherein the power converter converts the DC power output from the battery into AC power and supplies the AC power to the drive motor; and A winding switching device that switches the connection state of a plurality of windings in the drive motor is switched from a first connection state to a second connection state after the alternating current changes.

21. A computer program for use by a control device for controlling a drive motor for driving wheels of a vehicle, wherein: The computer program is used to make the computer execute the following steps: The output torque of the drive motor is changed by changing the AC current output from the power converter at a predetermined speed change timing of the vehicle, wherein the power converter converts the DC power output from the battery into AC power and supplies the AC power to the drive motor; and A winding switching device that switches the connection state of a plurality of windings in the drive motor is switched from a first connection state to a second connection state after the alternating current changes.

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