Electric vehicle

Abstract

The invention provides an electric vehicle capable of ensuring both the temperature rise of a storage battery and the required driving force during traveling. An electric vehicle is provided with: a first rotating electric machine that drives one of a front wheel and a rear wheel; a second rotating motor that drives 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 coolant circulation circuit capable of recovering heat generated by the first rotating electric machine using coolant and supplying the heat to the battery; and a control device that controls the driving of the first rotating electric machine and the second rotating electric machine, the first rotating electric machine being a winding excitation motor, the control device causing current to flow only to the stator coil instead of the rotor coil for the first rotating electric machine when temperature of the battery needs to be raised during travel, and causing current to flow only to the stator coil for the second rotating electric machine. Heat generated by the current flowing through the stator coil is recovered by the coolant of the coolant circulation circuit and supplied to the battery to raise the temperature of the battery, and the required driving force for driving is output by the second rotating electric machine.

Description

Technical Field

[0001] The present invention relates to electric vehicles. Background Art

[0002] Patent Document 1 discloses a technique in which a q-axis current value is set according to a required driving force required for traveling of an electric vehicle, and a d-axis current value is set in cooperation with the q-axis current value to promote a warm-up operation of a battery.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2012-165526 Summary of the invention

[0006] Problems to be solved by the invention

[0007] However, in the technology disclosed in Patent Document 1, it is difficult to ensure the required driving force while raising the temperature of the battery during the running of the electric vehicle, and unnecessary acceleration and deceleration may occur due to torque fluctuations.

[0008] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an electric vehicle capable of achieving both a temperature rise of a battery and ensuring a required driving force during traveling.

[0009] Technical solutions to solve problems

[0010] In order to solve the above-mentioned problems and achieve the purpose, the electric vehicle of the present invention comprises: a first rotating motor for driving one of the front wheels and the rear wheels; a second rotating motor for driving the other of the front wheel and the rear wheel; a battery capable of supplying electric power to the first rotating motor and the second rotating motor; a coolant circulation circuit capable of recovering heat generated by the first rotating motor by using coolant and supplying it to the battery; and a control device for controlling the driving of the first rotating motor and the second rotating motor, wherein the electric vehicle is characterized in that the first rotating motor is a winding excitation motor in which a rotor coil is wound without a permanent magnet on a rotor core and a stator coil is wound on a stator core, and the control device implements the following control when the battery needs to be heated during driving: for the first rotating motor, current is not allowed to flow in the rotor coil but only in the stator coil, the heat generated by causing current to flow in the stator coil is recovered by the coolant in the coolant circulation circuit and supplied to the battery to heat the battery, and the required driving force for driving is output by the second rotating motor.

[0011] This makes it possible to achieve both a temperature increase in the battery and a required driving force during traveling.

[0012] In the above, the second rotating electrical machine may be a permanent magnet type motor in which a permanent magnet is provided on a rotor core and a stator coil is wound on a stator core.

[0013] Thus, the driving force can be controlled by causing the current to flow through the stator coil of the second rotating electrical machine.

[0014] Effects of the Invention

[0015] The electric vehicle of the present invention has the effect of being able to achieve both a temperature rise in the battery and ensuring the required driving force during traveling. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a diagram schematically showing an electric vehicle according to an embodiment.

[0017] Figure 2 It is a diagram showing a schematic structure of a coil-excited motor according to an embodiment.

[0018] Figure 3 It is a diagram showing an example of a schematic configuration of a coolant circulation circuit according to an embodiment.

[0019] Figure 4 This is a flowchart showing an example of control related to battery temperature increase and driving force control performed by the electronic control device according to the embodiment. DETAILED DESCRIPTION

[0020] Hereinafter, an embodiment of the electric vehicle of the present invention will be described. However, the present invention is not limited to this embodiment.

[0021] Figure 1 1 is a diagram schematically showing an electric vehicle 1 according to an embodiment. The electric vehicle 1 includes a first rotating electric machine, namely a winding field motor 2, for driving the front wheels 10, and a second rotating electric machine, namely a PM motor (permanent magnet motor) 3, for driving the rear wheels 20. The winding field motor 2 has a rotor coil wound around a rotor core without a permanent magnet, and a stator coil wound around a stator core. The PM motor 3 has a permanent magnet on a rotor core, and a stator coil wound around a stator core.

[0022] Figure 2 2 is a diagram showing a schematic configuration of a coil-field motor 2 according to the embodiment. The coil-field motor 2 according to the embodiment is composed of a rotor 210, a stator 220, and the like.

[0023] The rotor 210 is composed of a rotor core 211 , a plurality of rotor salient poles 212 arranged along the circumferential direction of the rotor core 211 , a rotor coil 213 wound around the rotor salient poles 212 , and the like.

[0024] The rotor core 211 is an annular magnetic member having a plurality of rotor salient poles 212 arranged on the outer circumference and having a shaft hole in the center portion for fixing a shaft 230 serving as a rotation axis.

[0025] The rotor coil 213 is an excitation coil wound around the rotor salient pole 212. The rotor coil 213 passes through the inside of the slot 214 formed between the adjacent rotor salient poles 212 and is wound around the rotor salient pole 212 with a predetermined number of turns.

[0026] 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 multiple times around the teeth 222. Figure 2 Although only a part of the stator 220 is shown in FIG. 2 , the annular stator 220 is provided so as to surround the entire circumference of the rotor 210 .

[0027] The stator core 221 is a ring-shaped magnetic body component with a plurality of teeth 222 arranged on the inner circumference. 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 passes through the space between adjacent teeth 222, i.e., the slot 224, in sequence according to a predetermined distributed winding configuration method, and is wound around the predetermined teeth 222 in sequence. Each winding of the stator coil 223 wound around the teeth 222 is sequentially arranged along the circumference of the stator core 221, and the U-phase winding, the V-phase winding, and the W-phase winding are wound around one circle.

[0028] return Figure 1 The electric vehicle 1 of the embodiment includes a battery 5, which is a power storage device capable of supplying electric power to the winding field motor 2 and the PM motor 3. The winding field motor 2 is electrically connected to the battery 5 via the first inverter 4. The PM motor 3 is electrically connected to the battery 5 via the second inverter 6. Furthermore, by controlling the first inverter 4 and the second inverter 6 by the electronic control device 7, the winding field motor 2 and the PM motor 3 can function and operate as a motor or a generator.

[0029] In the electric vehicle 1, a first transaxle 8 for transmitting the power (torque) output from the coil excitation motor 2 to the front wheel 10 and a second transaxle 9 for transmitting the power (torque) output from the PM motor 3 to the rear wheel 20 are independently constructed. The first transaxle 8 is composed of a first speed reducer and a first differential device, etc. The second transaxle 9 is composed of a second speed reducer and a second differential device, etc. The coil excitation motor 2 is connected to the front wheel 10 via the first transaxle 8 in a manner that can transmit power. The PM motor 3 is connected to the rear wheel 20 via the second transaxle 9 in a manner that can transmit power.

[0030] The electronic control device 7 selects the drive of the coil-excitation motor 2 and the PM motor 3 based on the required driving force determined by the accelerator pedal depression amount (accelerator opening) and the vehicle speed, or based on the presence or absence of control related to the temperature increase of the battery 5.

[0031] The electronic control device 7 controls the drive of the winding excitation motor 2 and the PM motor 3. In addition, the electronic control device 7 controls the first inverter 4 and the second inverter 6 in order to control the drive of the winding excitation motor 2 and the PM motor 3. In addition, the electronic control device 7 implements control related to the state monitoring of the battery 5. A battery temperature sensor 51 for detecting the temperature of the battery 5 is installed in the battery 5. Based on the detection result of the battery temperature sensor 51, the electronic control device 7 can implement control related to the temperature increase of the battery 5 included in the control related to the state monitoring of the battery 5.

[0032] Figure 3 1 is a diagram showing an example of a schematic structure of the cooling liquid circulation circuit 30 according to the embodiment. Figure 3 As shown, the electric vehicle 1 of the embodiment includes a coolant circulation circuit 30 for cooling the winding excitation motor 2 and controlling the temperature of the battery 5. In the coolant circulation circuit 30, a battery heat exchange unit 31, a storage tank 32, a heat exchanger 33 and a pump 34 are sequentially arranged.

[0033] The battery heat exchanger 31 is provided on the battery 5 to exchange heat between the battery 5 and the coolant. The storage tank 32 stores the coolant. The heat exchanger 33 is, for example, an air-cooled radiator to cool the coolant. The pump 34 is, for example, an electric pump to pump the coolant along the coolant circulation loop 30. Figure 3 Specifically, when the pump 34 is operated, the coolant in the storage 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 storage tank 32. In addition, the control of the pump 34 is performed by the electronic control device 7.

[0034] In addition, the coolant circulation circuit 30 is configured to include a flow path of coolant for heat exchange between the winding excitation motor 2 and the coolant. In the coolant circulation circuit 30, the winding excitation motor 2 is arranged between the outlet of the pump 34 and the inlet of the battery heat exchange unit 31 in the flow direction of the coolant. As a result, the heat generated by the winding excitation motor 2 is recovered by the coolant, thereby cooling the winding excitation motor 2. In addition, the heat recovered by the coolant is transferred to the battery heat exchange unit 31, and is supplied to the battery 5 via the battery heat exchange unit 31. In addition, the coolant circulation circuit 30 of the embodiment is not limited to any one of the embodiments as long as it can transfer the heat generated by the winding excitation motor 2 to the battery 5. Figure 3In addition, in the electric vehicle 1 involved in the embodiment, the PM motor 3 may also have the same structure as the coolant circulation circuit 30, and a coolant circulation circuit configured with the PM motor 3 instead of the winding excitation motor 2 can be provided to transfer the heat generated by the PM motor 3 to the battery 5.

[0035] In the electric vehicle 1 of the embodiment, when the temperature of the battery 5 is lower than a preset threshold temperature based on the detection result of the battery temperature sensor 51, control related to the temperature increase of the battery 5 is implemented. Here, the winding field motor 2 is a magnetless motor, and generates magnetic flux by causing current to flow in the rotor coil 213 (excitation coil), and controls the driving force (torque) by using the current flowing in the stator coil 223. In other words, in the winding field motor 2, if the current is not flowing in the rotor coil 213, the driving force (torque) is not output. Therefore, in the electric vehicle 1 of the embodiment, when the temperature increase (preheating) of the battery 5 is required during driving, the winding field motor 2 is made to flow only in the stator coil 223 instead of the rotor coil 213 from the battery 5 via the first inverter 4, and the heat generated by the current flowing in the stator coil 223 is recovered from the winding field motor 2 by the coolant of the coolant circulation circuit 30 and provided to the battery 5, and used for the temperature increase of the battery 5. At this time, the current flows from the battery 5 to the stator coil of the PM motor 3 , so that the PM motor 3 outputs the required driving force to control the driving force during traveling.

[0036] Figure 4 This is a flowchart showing an example of control related to battery temperature increase and driving force control performed by the electronic control device 7 of the embodiment. Figure 4 The control shown is performed while the electric vehicle 1 is traveling.

[0037] First, the electronic control device 7 obtains the temperature of the battery 5 detected by the battery temperature sensor 51 (step S1). Next, the electronic control device 7 determines whether the temperature of the battery 5 needs to be increased (step S2). For example, when the temperature of the battery 5 obtained is higher than a preset threshold temperature and the temperature increase of the battery 5 is determined to be unnecessary (No in step S2), the electronic control device 7 ends a series of controls. On the other hand, when the temperature of the battery 5 obtained is lower than the threshold temperature and the temperature increase of the battery 5 is required (Yes in step S2), the electronic control device 7 transfers to step S3. In step S3, for the coil-excitation motor 2, the electronic control device 7 causes the current to flow to the stator coil 223 instead of from the battery 5, and recovers the heat generated by causing the current to flow to the stator coil 223 using the coolant in the coolant circulation circuit 30 and supplies it to the battery 5, thereby increasing the temperature of the battery 5 (step S3). Next, the electronic control device 7 flows current from the battery 5 to the stator coil of the PM motor 3 to control the driving force by causing the PM motor 3 to output the required driving force for traveling (step S4 ). Thereafter, the electronic control device 7 ends a series of controls.

[0038] In the electric vehicle 1 of the embodiment, for example, the electronic control device 7 implements Figure 4 The control related to the battery temperature increase and the driving force control as shown can achieve both the temperature increase of the battery 5 and the securing of the required driving force during traveling.

[0039] In addition, in the above-mentioned embodiment, the PM motor 3 is used as the second rotating electric machine for controlling the driving force during driving, but the second rotating electric machine may also be a winding field motor as the first rotating electric machine. That is, in the electric vehicle 1 of the embodiment, if a winding field motor is used as the first rotating electric machine for heating the battery 5 during driving, the type of the second rotating electric machine for controlling the driving force is not particularly limited.

[0040] In addition, in the electric vehicle 1 of the above-mentioned embodiment, if Figure 1 As shown, the front wheel 10 is driven by the winding field motor 2 as the first rotating electrical machine, and the rear wheel 20 is driven by the PM motor 3 as the second rotating electrical machine, but the present invention is not limited thereto. That is, the electric vehicle 1 of the embodiment may also be configured such that the rear wheel 20 is driven by the winding field motor 2 as the first rotating electrical machine, and the front wheel 10 is driven by the PM motor 3 as the second rotating electrical machine.

[0041] Description of Reference Numerals

[0042] 1 Electric Vehicles

[0043] 2-winding excitation motor

[0044] 3 PM motor

[0045] 4 First converter

[0046] 5. Battery

[0047] 6 Second converter

[0048] 7 Electronic Control Unit

[0049] 8 First transaxle

[0050] 9 Second transaxle

[0051] 10 Front wheel

[0052] 20 Rear wheel

[0053] 30 Coolant circulation circuit

[0054] 31 Battery heat exchange unit

[0055] 32 Storage Box

[0056] 33 Heat exchanger

[0057] 34 Pumps

[0058] 51 Battery temperature sensor

[0059] 210 Rotor

[0060] 211 rotor core

[0061] 212 rotor salient poles

[0062] 213 rotor coil

[0063] 214 slots

[0064] 220 Stator

[0065] 221 stator core

[0066] 222 teeth

[0067] 223 Stator Coil

[0068] 224 slots

[0069] 230 Axis

Claims

1. An electric vehicle comprising: A first rotating motor, used to drive one of the front wheels and the rear wheels; a second rotating motor, for driving the other of the front wheel and the rear wheel; a battery capable of supplying electric power to the first rotating electric machine and the second rotating electric machine; a coolant circulation circuit capable of recovering heat generated by the first rotating electrical machine using coolant and supplying the heat to the battery; and A control device controls the driving of the first rotating electrical machine and the second rotating electrical machine, wherein the electric vehicle is characterized in that: The first rotating electrical machine is a winding excitation motor in which a rotor coil is wound around a rotor core without a permanent magnet and a stator coil is wound around a stator core. When the battery needs to be heated during driving, the control device implements the following control: for the first rotating motor, the current does not flow in the rotor coil but only flows in the stator coil, the coolant in the coolant circulation circuit is used to recover the heat generated by the current flowing in the stator coil and supply it to the battery to heat the battery, and the second rotating motor is used to output the required driving force for driving.

2. The electric vehicle according to claim 1, characterized in that: The second rotating electrical machine is a permanent magnet type motor in which a permanent magnet is provided on the rotor core and the stator coil is wound on the stator core.

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