Electric vehicles
The dual motor system with a wound-field and permanent magnet motor, combined with a coolant circuit, addresses battery warming and driving force challenges, stabilizing vehicle performance by maintaining temperature and torque control.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- TOYOTA JIDOSHA KK
- Filing Date
- 2023-10-17
- Publication Date
- 2026-05-26
AI Technical Summary
Existing electric vehicle technologies face challenges in ensuring both battery warming and required driving force during operation, often leading to torque fluctuations and unnecessary acceleration or deceleration.
The electric vehicle employs a dual motor system comprising a wound-field motor and a permanent magnet motor, with a coolant circulation circuit to recover heat from the wound-field motor and transfer it to the battery, while the permanent magnet motor provides driving force, and a control device manages current distribution to achieve both battery warming and driving force.
This approach effectively maintains battery temperature and ensures required driving force during operation, stabilizing vehicle performance by minimizing torque fluctuations.
Smart Images
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Abstract
Description
Technical Field
[0001] The present invention relates to an electric vehicle.
Background Art
[0002] Patent Document 1 discloses a technique for setting a q-axis current value according to a required driving force necessary for the running of an electric vehicle, and setting a d-axis current value that promotes the warming operation of a battery in cooperation with the q-axis current value.
Prior Art Document
Patent Document
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] However, in the technique disclosed in Patent Document 1, it is difficult to ensure the required driving force while warming up the battery during the running of the electric vehicle, and there is a risk of causing unnecessary acceleration and deceleration due to torque fluctuations.
[0005] The present invention has been made in view of the above problems, and an object thereof is to provide an electric vehicle capable of achieving both warming up of the battery and ensuring the required driving force during running.
Means for Solving the Problems
[0006] To solve the above-mentioned problems and achieve the objective, the electric vehicle according to the present invention comprises: a first rotating electric machine for driving one of the front wheels and the rear wheels; a second rotating electric machine for driving the other of the front wheels and the rear wheels; a battery capable of supplying power to the first rotating electric machine and the second rotating electric machine; a coolant circulation circuit capable of recovering the heat generated by the first rotating electric machine with a coolant and supplying it to the battery; and a control device for controlling the driving of the first rotating electric machine and the second rotating electric machine, wherein the first rotating electric machine has a rotor core with permanent magnets This is a wound-field motor in which a rotor coil is wound around a stator core without a rotor coil, and a stator coil is wound around a stator core. The control device is characterized in that, when it is necessary to raise the temperature of the battery during driving, it supplies current only to the stator coil to the first rotating electric motor without supplying current to the rotor coil, recovers the heat generated by supplying current to the stator coil with the coolant in the coolant circulation circuit and supplies it to the battery to raise the temperature of the battery, and outputs the required driving force for driving with the second rotating electric motor.
[0007] This makes it possible to achieve both battery temperature rise and the securing of required driving force while driving.
[0008] Furthermore, in the above, the second rotating electric machine may be a permanent magnet type motor in which permanent magnets are provided on the rotor core and stator coils are wound around the stator core.
[0009] This allows the driving force to be controlled by supplying current to the stator coil of the second rotating electric machine. [Effects of the Invention]
[0010] The electric vehicle according to the present invention has the effect of achieving both battery temperature rise and securing the required driving force while driving. [Brief explanation of the drawing]
[0011] [Figure 1] Figure 1 is a schematic diagram showing an electric vehicle according to an embodiment. [Figure 2] Figure 2 is a diagram showing the schematic configuration of a wound-field motor according to an embodiment. [Figure 3] Figure 3 shows an example of a schematic configuration of a coolant circulation circuit according to the embodiment. [Figure 4] Figure 4 is a flowchart showing an example of control related to battery temperature rise and driving force control performed by the electronic control device according to the embodiment. [Modes for carrying out the invention]
[0012] The following describes an embodiment of the electric vehicle according to the present invention. However, the present invention is not limited to this embodiment.
[0013] Figure 1 is a schematic diagram showing an electric vehicle 1 according to an embodiment. The electric vehicle 1 comprises a wound-field motor 2, which is a first rotating electric motor for driving the front wheels 10, and a PM motor (permanent magnet motor) 3, which is a second rotating electric motor for driving the rear wheels 20. In the wound-field motor 2, the rotor coil is wound around the rotor core without permanent magnets, and the stator coil is wound around the stator core. In the PM motor 3, the rotor core is provided with permanent magnets, and the stator coil is wound around the stator core.
[0014] Figure 2 is a diagram showing the schematic configuration of a wound-field motor 2 according to an embodiment. The wound-field motor 2 according to this embodiment is composed of a rotor 210 and a stator 220, etc.
[0015] The rotor 210 consists of a rotor core 211, a plurality of rotor salient poles 212 arranged along the circumferential direction of the rotor core 211, and rotor coils 213 wound around the rotor salient poles 212.
[0016] The rotor core 211 is an annular magnetic member having multiple rotor salient poles 212 arranged on its outer circumference and a shaft hole in its center to which a shaft 230, which is the axis of rotation, is fixed.
[0017] The rotor coil 213 is a field coil wound around the rotor salient pole 212. The rotor coil 213 is wound around the rotor salient pole 212 with a predetermined number of turns through the inside of the slot 214 formed between adjacent rotor salient poles 212.
[0018] The stator 220 is composed of a stator core 221, a plurality of teeth 222 arranged along the circumferential direction of the stator core 221, and a stator coil 223 wound around the teeth 222 a plurality of times. Although only a part of the stator 220 is shown in FIG. 2, an annular stator 220 is provided so as to surround the entire circumference of the rotor 210.
[0019] The stator core 221 is an annular magnetic member on the inner peripheral side where a plurality of teeth 222 are arranged. The stator coil 223 includes three-phase windings of a U-phase winding, a V-phase winding, and a W-phase winding. Each phase winding sequentially passes through the slot 224, which is the space between adjacent teeth 222, and is sequentially wound around a predetermined tooth 222 according to a predetermined distributed winding arrangement method. Each winding of the stator coil 223 wound around the teeth 222 is arranged such that the U-phase winding, the V-phase winding, and the W-phase winding are sequentially arranged and go around once along the circumferential direction of the stator core 221.
[0020] Returning to FIG. 1, the electric vehicle 1 according to the embodiment includes a battery 5, which is a power storage device capable of supplying power to the wound-field motor 2 and the PM motor 3. The wound-field motor 2 is electrically connected to the battery 5 via a first inverter 4. The PM motor 3 is electrically connected to the battery 5 via a second inverter 6. By controlling the first inverter 4 and the second inverter 6 by an electronic control device 7, the wound-field motor 2 and the PM motor 3 can be operated as motors or generators.
[0021] In the electric vehicle 1, a first transaxle 8 that transmits the power (torque) output from the wound-field magnet motor 2 to the front wheels 10 and a second transaxle 9 that transmits the power (torque) output from the PM motor 3 to the rear wheels 20 are independently configured. The first transaxle 8 is composed of a first reduction gear, a first differential device, and the like. The second transaxle 9 is composed of a second reduction gear, a second differential device, and the like. The wound-field magnet motor 2 is connected to the front wheels 10 via the first transaxle 8 so as to be power-transmittable. The PM motor 3 is connected to the rear wheels 20 via the second transaxle 9 so as to be power-transmittable.
[0022] The selection of driving the wound-field magnet motor 2 and the PM motor 3 by the electronic control device 7 is performed based on, for example, the required driving force determined by the amount of depression of the accelerator pedal (accelerator opening) and the vehicle speed, or is performed according to the presence or absence of control regarding the temperature rise of the battery 5.
[0023] The electronic control device 7 controls the driving of the wound-field magnet motor 2 and the PM motor 3. Further, the electronic control device 7 controls the first inverter 4 and the second inverter 6 for controlling the driving of the wound-field magnet motor 2 and the PM motor 3. Furthermore, the electronic control device 7 performs control regarding the state monitoring of the battery 5. A battery temperature sensor 51 for detecting the temperature of the battery 5 is attached to the battery 5. The electronic control device 7 can perform control regarding the temperature rise of the battery 5, which is included in the control regarding the state monitoring of the battery 5, based on the detection result of the battery temperature sensor 51.
[0024] FIG. 3 is a diagram showing an example of the schematic configuration of the coolant circulation circuit 30 according to the embodiment. As shown in FIG. 3, the electric vehicle 1 according to the embodiment includes a coolant circulation circuit 30 for cooling the wound-field magnet motor 2 and controlling the temperature of the battery 5. In the coolant circulation circuit 30, a battery heat exchange section 31, a reserve tank 32, a heat exchanger 33, and a pump 34 are arranged in this order.
[0025] The battery heat exchange unit 31 is provided on the battery 5 to exchange heat between the battery 5 and the coolant. The reserve tank 32 stores the coolant. The heat exchanger 33 is, for example, an air-cooled radiator, which cools the coolant. The pump 34 is, for example, electrically powered, and circulates the coolant in the direction of the arrow in Figure 3 within the coolant circulation circuit 30. Specifically, when the pump 34 operates, the coolant in the reserve tank 32 is supplied to the battery heat exchange unit 31 via the heat exchanger 33. The coolant that has passed through the battery heat exchange unit 31 returns to the reserve tank 32. The pump 34 is controlled by the electronic control unit 7.
[0026] Furthermore, the coolant circulation circuit 30 is configured to include a coolant flow path for heat exchange between the wound-field motor 2 and the coolant. In the coolant circulation circuit 30, the wound-field motor 2 is positioned between the outlet of the pump 34 and the inlet of the battery heat exchange unit 31 in the direction of coolant flow. As a result, the heat generated by the wound-field motor 2 is recovered by the coolant, and the wound-field motor 2 is cooled. The heat recovered by the coolant is then transferred to the battery heat exchange unit 31 and supplied to the battery 5 via the battery heat exchange unit 31. Note that the coolant circulation circuit 30 according to this embodiment is not limited to the configuration shown in Figure 3, as long as it is capable of transferring the heat generated by the wound-field motor 2 to the battery 5. Also, in the electric vehicle 1 according to this embodiment, a coolant circulation circuit similar to the coolant circulation circuit 30 may be provided for the PM motor 3, but with the PM motor 3 instead of the wound-field motor 2, so that the heat generated by the PM motor 3 can be transferred to the battery 5.
[0027] In the electric vehicle 1 according to this embodiment, based on the detection result of the battery temperature sensor 51, control is performed to raise the temperature of the battery 5 when the temperature of the battery 5 is lower than a preset threshold temperature. Here, the wound-field motor 2 is a magnetless motor, and magnetic flux is generated by passing current through the rotor coil 213 (field coil), and the driving force (torque) is controlled by the current flowing through the stator coil 223. In other words, in the wound-field motor 2, no driving force (torque) is output unless current is passed through the rotor coil 213. Therefore, in the electric vehicle 1 according to this embodiment, if it is necessary to raise the temperature of the battery 5 during driving, current is passed from the battery 5 to the wound-field motor 2 via the first inverter 4, and current is passed only to the stator coil 223 without passing through the rotor coil 213. The heat generated by passing current through the stator coil 223 is recovered from the wound-field motor 2 by the coolant in the coolant circulation circuit 30 and supplied to the battery 5 to raise the temperature of the battery 5. Furthermore, by supplying current from the battery 5 to the stator coil of the PM motor 3, the PM motor 3 outputs the required driving force to control the driving force during operation.
[0028] Figure 4 is a flowchart showing an example of control related to battery temperature rise and driving force control performed by the electronic control device 7 according to this embodiment. Note that the control shown in Figure 4 is performed while the electric vehicle 1 is running.
[0029] First, the electronic control unit 7 obtains the temperature of the battery 5 detected by the battery temperature sensor 51 (step S1). Next, the electronic control unit 7 determines whether or not it is necessary to raise the temperature of the battery 5 (step S2). For example, if the electronic control unit 7 determines that the obtained temperature of the battery 5 is above a preset threshold temperature and that it is not necessary to raise the temperature of the battery 5 (No in step S2), it terminates the series of controls. On the other hand, if the electronic control unit 7 determines that the obtained temperature of the battery 5 is lower than the threshold temperature and that it is necessary to raise the temperature of the battery 5 (Yes in step S2), it proceeds to step S3. In step S3, the electronic control unit 7 sends current from the battery 5 to the wound field motor 2, but does not send current to the rotor coil 213, and recovers the heat generated by the current flowing through the stator coil 223 using the coolant in the coolant circulation circuit 30 and supplies it to the battery 5 to raise the temperature of the battery 5 (step S3). Next, the electronic control unit 7 supplies current from the battery 5 to the stator coil of the PM motor 3, and controls the driving force by outputting the required driving force for driving from the PM motor 3 (step S4). After that, the electronic control unit 7 terminates the series of controls.
[0030] In the electric vehicle 1 according to this embodiment, for example, the electronic control unit 7 performs control related to battery temperature rise and driving force control as shown in Figure 4, thereby enabling both battery temperature rise and securing the required driving force during driving.
[0031] In the embodiment described above, a PM motor 3 is used as the second rotating electric motor for controlling the driving force during operation. However, a wound-field motor may also be used for the second rotating electric motor, similar to the first rotating electric motor. In other words, in the electric vehicle 1 according to this embodiment, if a wound-field motor is used as the first rotating electric motor for raising the temperature of the battery 5 during operation, the type of second rotating electric motor for controlling the driving force is not particularly limited.
[0032] Furthermore, in the electric vehicle 1 according to the above-described embodiment, as shown in Figure 1, the front wheels 10 are driven by a wound-field motor 2, which is the first rotating electric motor, and the rear wheels 20 are driven by a PM motor 3, which is the second rotating electric motor, but the configuration is not limited to this. That is, the electric vehicle 1 according to the embodiment may be configured so that the rear wheels 20 are driven by a wound-field motor 2, which is the first rotating electric motor, and the front wheels 10 are driven by a PM motor 3, which is the second rotating electric motor. [Explanation of Symbols]
[0033] 1. Electric Vehicle 2. Winding field motor 3 PM Motor 4. First Inverter 5 batteries 6. Second Inverter 7. Electronic control unit 8 First transaxle 9 Second transaxle 10 Front Wheel 20 Rear wheels 30 Coolant circulation circuit 31 Battery heat exchange unit 32 Reserve Tank 33 Heat exchanger 34 pumps 51 Battery temperature sensor 210 rotors 211 Rotor Core 212 Rotor salient poles 213 Rotor Coil 214 slots 220 stator 221 Stator Core 222 Teeth 223 Stator Coil 224 slots 230 shaft
Claims
1. A first rotating electric motor for driving either the front wheel or the rear wheel, A second rotating electric motor for driving the other of the front wheel and the rear wheel, A battery capable of supplying power to the first rotating electric machine and the second rotating electric machine, A cooling fluid circulation circuit capable of recovering the heat generated by the first rotating electric machine with a cooling fluid and supplying it to the battery, A control device for controlling the drive of the first rotating electric machine and the second rotating electric machine, An electric vehicle equipped with, The aforementioned first rotating electric machine is a wound-field motor in which rotor coils are wound around a rotor core without permanent magnets, and stator coils are wound around a stator core. The control device is An electric vehicle characterized in that, when it is necessary to raise the temperature of the battery during operation, current is supplied only to the stator coil of the first rotating electric motor without supplying current to the rotor coil, the heat generated by supplying current to the stator coil is recovered by the coolant in the coolant circulation circuit and supplied to the battery to raise the temperature of the battery, and the second rotating electric motor outputs the required driving force for driving.
2. The electric vehicle according to claim 1, characterized in that the second rotating electric machine is a permanent magnet type motor in which permanent magnets are provided on the rotor core and stator coils are wound around the stator core.