Control device for electric vehicle

Abstract

To improve utilization efficiency of a battery and recovery efficiency of energy in an electric vehicle.SOLUTION: The control device 10 used for an electric vehicle 11 including a battery 14, a motor 13, an inverter 16 connected to the motor 13, and a heat transfer device 20 capable of transferring heat between the battery 14 and the motor 13 using a fluid as a medium is configured to selectively switch between ASC control and regenerative charging control for the inverter 16, and to execute warm-up control for transferring heat of the motor 13 to the battery 14 by the heat transfer device 20 for the motor 13 connected to the inverter 16 executing the ASC control.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to brake control for electric vehicles. [Background technology]

[0002] In electric vehicles, when braking, the required torque is achieved by coordinating regenerative braking with hydraulic braking. The electrical energy generated by the regenerative braking is recovered and used to charge the battery. Hydraulic braking converts kinetic energy into thermal energy, which is then discarded into the atmosphere.

[0003] From the viewpoint of energy efficiency, it is desirable to make maximum use of regenerative braking. However, regenerative braking has limitations in terms of battery capacity and input power. Regenerative braking cannot be made to work beyond the maximum input power of the battery, and the insufficient braking force must be compensated for by hydraulic braking. Furthermore, the power of regenerative braking depends on the product of force and speed, and the higher the speed, the smaller the upper limit tends to be. In other words, the higher the speed, the more likely it is that hydraulic braking will be required even when the same braking force is required.

[0004] Furthermore, overcharging a battery beyond its capacity shortens its lifespan and also leads to a decrease in capacity. For this reason, there is a need for control to prevent the battery from being overcharged. For example, Patent Document 1 discloses an electric vehicle that uses ASC (Active Short Circuit) control to prevent the battery from being overcharged by providing a discharge circuit in a circuit connected to the motor and enabling rapid discharge even while the motor is rotating. In ASC control, all upper-stage switches in the inverter circuit between the motor and the battery are turned off and all lower-stage switches are turned on, so that current from the motor does not flow to the battery but is circulated within the circuit, generating heat and releasing energy. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2022-181191 Summary of the Invention [Problem to be solved by the invention]

[0006] However, simply performing ASC control simply releases thermal energy into the atmosphere, and even though it protects the battery, the thermal energy is wasted.

[0007] On the other hand, battery performance fluctuates greatly depending on the temperature. In particular, the maximum input / output power drops significantly when temperatures drop below freezing. This reduces the braking force of the regenerative brakes, which are limited by the battery's maximum input power, and increases the likelihood that braking force will have to be secured by hydraulic brakes. This results in even more wasted thermal energy.

[0008] SUMMARY OF THE INVENTION It is therefore an object of the present invention to improve the energy recovery efficiency in an electric vehicle. [Means for solving the problem]

[0009] This invention is A control device for use in a vehicle, the control device including a battery, a motor, an inverter connected to the motor, and a heat transfer device capable of transferring heat between the battery and the motor using a fluid as a medium, The inverter can be selectively switched between ASC control and regenerative charging control, The above problem was solved by the first solution, which is a control device that performs warm-up control for the motor connected to the inverter that is performing the ASC control, by using the heat transfer device to transfer heat from the motor and the inverter to the battery.

[0010] In addition, the present invention provides a first solution, the vehicle has hydraulic brakes; The control device When the ASC control is being executed, the ASC torque generated by the ASC control is subtracted from the target braking force during braking to calculate a required braking force for the hydraulic brake, When the regenerative charging control is being executed, the required braking force is calculated by subtracting the braking force due to the regenerative charging control from the target braking force during braking. A second solution can be adopted.

[0011] Furthermore, in the first or second solving means of the present invention, the vehicle has a combination of a plurality of motors and the inverter; the control device executes the regenerative charge control using at least one of the plurality of motor and inverter combinations, executes the ASC control using the remaining of the plurality of motor and inverter combinations, and transfers heat by circulating the fluid between the remaining motor and the battery. A third solution can be adopted.

[0012] Furthermore, in the first or second solving means of the present invention, the vehicle has one motor, The vehicle acquires a charging rate of the battery, The control device executes the ASC control if the charging rate is equal to or higher than a predetermined value, and executes the regenerative charging control if the charging rate is lower than the predetermined value. A fourth solution can be adopted. [Effects of the Invention]

[0013] This invention allows energy that would previously have been wasted and released into the atmosphere as heat to be recovered and used to warm up the battery, expanding the range of regenerative braking that can be performed and improving the vehicle's energy efficiency. Previously, a PTC heater was used to warm up the battery, but by using heat generated by the ASC to warm up the battery, the energy used for the PTC heater can be saved and the battery can be warmed up quickly, reducing the battery's internal resistance and improving battery charging efficiency. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a functional block diagram showing a first embodiment of an electric vehicle controlled by a control device according to the present invention; [Figure 2] Figure 1 shows the inverter in operation with regenerative charging control and ASC control. [Figure 3] FIG. 2 is a functional block diagram showing an example of a heat transfer device controlled by a control device in the embodiment of FIG. 1. [Figure 4] A graph showing the change in the total braking force due to regenerative braking and ASC torque versus vehicle speed [Figure 5] 1 is a flow diagram illustrating a control flow by a control device according to a first embodiment; [Figure 6] FIG. 2 is a functional block diagram showing a second embodiment of an electric vehicle controlled by the control device according to the present invention; [Figure 7] Figure 6: Situation in which ASC control is being performed by the inverter [Figure 8] Figure 6: Situation in which regenerative charging control is being performed by the inverter DETAILED DESCRIPTION OF THE INVENTION

[0015] An embodiment of the present invention will be described below. A control device 10 according to the present invention controls a vehicle. The vehicle is an electric vehicle that can run by driving a motor 13 to rotate wheels 15. It may be a pure electric vehicle, or an electric vehicle with multiple power sources such as a hybrid vehicle or a fuel cell vehicle. In the case of a hybrid vehicle, it may not only be charged by power generated by an engine, but may also be a plug-in hybrid vehicle (PHEV) that is equipped with an external charger that can charge power from an external source and an external power feeder that can supply power to the outside. In the following description, a pure electric vehicle 11 will be used as an example, but the present invention is not limited to this.

[0016] The control device 10 according to the present invention may be configured as part of the functions of an ECU (Electronic Control Unit) that controls the electric vehicle 11 itself, or may be configured as hardware attached separately from the ECU. When configured as part of the ECU, the control device 10 is easy to combine with hardware used for normal driving and is easy to implement.

[0017] Regardless of the configuration, the control device 10 includes a calculation unit, a temporary memory used for calculations, and a non-transitory computer-readable storage medium for storing programs and data. The control device 10 also includes an interface for exchanging data and signals with each part of the electric vehicle 11.

[0018] FIG. 1 shows a functional block diagram of a first embodiment of an electric vehicle 11 embodying the present invention. The electric vehicle 11 has a battery 14 that can charge and supply power used to drive the vehicle. The battery 14 can be a large-capacity secondary battery, such as a nickel-metal hydride battery, a lithium-ion battery, or a sodium-ion battery. In particular, batteries whose input / output power drops below freezing point can be used effectively with the warm-up control of the present invention. Note that a 12V lead-acid battery (not shown) may also be subject to the warm-up control described below.

[0019] The electric vehicle 11 has a motor 13. In this embodiment, the electric vehicle 11 has two motors 13. The electric vehicle 11 also has a front wheel motor 13a that drives the front wheels 15a and a rear wheel motor 13b that drives the rear wheels 15b.

[0020] The electric vehicle 11 also has inverters 16a and 16b that convert DC current from the motors 13a and 13b and the battery 14 into AC current. The inverters 16a and 16b are equipped with a plurality of switches 19. The electric vehicle 11 can use the energy applied to the motors 13a and 13b as regenerative braking by inputting the power generated by the motors 13a and 13b into the battery 14 via the inverters 16a and 16b.

[0021] An example of inverters 16a, 16b between the motors 13a, 13b and the battery 14 is shown in FIG. 2. The front and rear motors 13a, 13b have three-phase windings connected in a Y-connection. Each of the motors 13a, 13b has a diode 18 and a PWM (Pulse Width Modulation) controllable switch 19 connected in three-phase parallel to each other, along with the inverters 16a, 16b. These switches 19 are controlled by the control device 10.

[0022] The electric vehicle 11 further includes a heat transfer device 20 capable of transferring heat between the battery 14, the motors 13a and 13b, and the inverters 16a and 16b using a fluid as a medium. An example of the configuration of the heat transfer device 20 is shown in FIG. 3. Heat exchangers 21 (21a and 21b), through which a fluid passes, are provided around the motors 13 (13a and 13b) and the inverters 16 (16a and 16b). Fluid switches 23 (23a and 23b), which can switch the flow, are provided on flow paths 22 (22a and 22b) from the heat exchanger 21. The fluid switches 23 are, for example, three-way valves. The fluid switches 23 (SW23a and SW23b) are controlled by the control device 10. The flow path 22 is branched by the fluid switches 23 to the battery 14 and the radiator 24. The heat exchanger 21 is also provided with a pump (not shown) for circulating the fluid. In the heat exchanger 21, when the fluid switch 23 is switched to connect the flow paths 22a and 22b to the battery 14, the fluid absorbs heat around the motor 13 and the inverter 16. This fluid is supplied to the area around the battery 14, thereby transferring the heat from the motor 13 and the inverter 16 to the battery 14. On the other hand, in the heat exchanger 21, when the fluid switch 23 is switched to connect the flow paths 22a and 22b to the radiator 24, the heat from the motor 13 is released into the atmosphere via the radiator 24. The fluid used in this heat transfer device 20 may be air-cooled using a gas such as air, or liquid-cooled using water or oil, but liquid-cooled fluid is preferable in terms of heat capacity.

[0023] Furthermore, the electric vehicle 11 has hydraulic brakes 30 that act on the front wheels 15a or the rear wheels 15b. These hydraulic brakes 30 do not directly reflect the depression of the brake pedal, but rather only provide a portion of the required braking force determined by the depression of the brake pedal. In other words, the hydraulic brakes 30 provide the remaining portion of the required braking force, excluding the portion that can be provided by regenerative braking through regenerative charging control and the portion that can be provided by heat through ASC control, which will be described later.

[0024] The control device 10 switches on the individual switches 19 for the inverters 16a and 16b connected to the motors 13a and 13b. That is, the control device 10 controls the inverter 16a on the front wheel 15a side to connect the front wheel motor 13a and the battery 14. In this embodiment, this control is referred to as regenerative charging control. The control device 10 also controls the other motor 13 and all of the lower switches 19 to be on and all of the upper switches 19 to be off. Hereinafter, this control is referred to as ASC control. This relationship does not need to be fixed, and the order may be reversed as necessary. However, in this embodiment in which there are two motors 13, the control device 10 performs regenerative charging control with one inverter 16 (16a and 16b) and ASC control with the other inverter 16 (16b and 16a). In this manner, the electric vehicle 11 can prevent overcharging and heat the battery 14 while maintaining the regenerative braking function.

[0025] In the example shown in FIG. 2 , the inverter 16a on the front wheel 15a side connects the front wheel motor 13a to the battery 14. The inverter 16a charges the battery 14 with regenerated energy. On the other hand, the inverter 16b on the rear wheel 15b side has all of its lower switches 19 turned on and all of its upper switches 19 turned off to prevent current from flowing from the rear wheel motor 13b to the battery 14. ASC control is originally a fail-safe control to prevent unintended charging in the event of a motor failure at high speed. However, in this invention, ASC control is used as a means of recovering energy by heat. When ASC control is executed, power from the motor 13b is not supplied to the battery 14, but is instead generated and consumed by the inverter 16b and the coils of the rear wheel motor 13b. This heat is recovered by the heat transfer device 20 using a fluid passing through a heat exchanger 21 and used to maintain the temperature and heat the battery 14.

[0026] Normally, the control device 10 performs regenerative charging control on the front wheels 15a and ASC control on the rear wheels 15b. This is because, during braking, weight is applied to the front wheels, so it is preferable to apply regenerative braking on the front wheels. However, if the rear wheel motor 13b on the rear wheel 15b side, which is subjected to ASC control, becomes too hot and exceeds a predetermined temperature, the control device 10 may switch the front and rear controls.

[0027] The battery 14 has a charging rate acquisition unit that acquires the charging rate and a temperature acquisition unit that acquires the temperature. This is so that the control device 10 can use the acquired charging rate as a basis for deciding whether to switch control. However, it is difficult for the charging rate acquisition unit to directly measure the charging rate of the battery 14. For this reason, the control device 10 realizes the charging rate acquisition unit by acquiring the voltage using a voltmeter 31 and an ammeter attached to the battery 14 and determining the charging rate by referring to a map of voltage and charging rate that is stored in a memory unit for use in advance. Meanwhile, the temperature acquisition unit is configured as a thermometer 32 provided at a position that serves as a reference for determining the external temperature, internal temperature, etc. of the battery 14.

[0028] The control device 10 switches between the flow paths 22a and 22b of the heat transfer device 20 using a fluid switch 23 (23a, 23b). The control device 10 controls the fluid switch 23 so that fluid from the motor 13 and the inverter 16 flows to the battery 14. As a result, heat from the motor 13 and the inverter 16 is supplied to the battery 14 to warm it up. In this embodiment, the control of the fluid switch 23 by the control device 10 in this manner is referred to as warm-up control. The control device 10 also controls the fluid switch 23 so that fluid flows to the radiator 24. As a result, heat is released into the atmosphere in the flow path 22, resulting in heat exhaust control. The control device 10 uses the temperature of the battery 14, as determined by the temperature acquisition unit, as a criterion for switching between these modes. The maximum value of input / output power decreases when the battery 14 is cold. To resolve this situation, if the temperature is below a predetermined temperature, the control device 10 performs warm-up control, which involves warming up the motor 13a and the inverter 16 using ASC control and recovering the heat using the heat transfer device 20 to supply it to the battery 14. On the other hand, if the battery 14 is at or above a predetermined temperature, the control device 10 performs heat exhaust control, in which the heat generated by the motor 13a during ASC control is not sent to the battery 14 but is sent to the radiator 24 for exhaust. This is because there is no need to heat the battery 14, and heating the battery may actually reduce its performance. This predetermined temperature may be adjusted as appropriate depending on the vehicle design. For example, warm-up control may be performed when the battery temperature is below 15°C, and exhaust heat control may be performed when the battery temperature is above 40°C.

[0029] Furthermore, when the driver operates the brake pedal (not shown), the control device 10 calculates the required braking force for the hydraulic brakes 30 by subtracting the braking force (regenerative brake torque) due to regenerative charging control from the target braking force due to that operation. Furthermore, because the control device 10 also performs ASC control in parallel, the control device 10 calculates the required braking force for the hydraulic brakes 30 by subtracting the ASC torque lost from the wheels 15a, 15b and motors 13a, 13b due to ASC control from the target braking force. However, of these, regenerative braking is given priority. The energy of the regenerative brake torque is recovered to charge the battery 14. In contrast, the ASC torque due to the ASC control is ultimately released into the atmosphere as heat. For this reason, the priority is lowered. The control device 10 secures the amount of regenerative power by using the regenerative brake up to the upper limit of the regenerative brake torque, and when the sum of the regenerative brake torque and the ASC torque is less than the target braking force, the control device 10 also uses the ASC torque and sets the amount obtained by subtracting the sum of the regenerative brake torque and the ASC torque as the braking force required of the hydraulic brake 30. On the other hand, when the amount obtained by subtracting the regenerative brake from the target braking force is less than the ASC torque, the control device 10 does not use the ASC torque and sets the amount obtained by subtracting the regenerative brake torque from the target braking force as the braking force required of the hydraulic brake 30. This is because adjusting the ASC torque is difficult.

[0030] The relationship between this upper limit of regenerative braking torque and ASC torque is shown in Figure 4. The horizontal axis is vehicle speed, and the vertical axis is braking force. The higher the vehicle speed, the lower the upper limit of regenerative braking torque. ASC torque rises up to a vehicle speed of around 10-20 km / h, but decreases as the vehicle speed increases beyond that. However, this change is smaller than that of regenerative braking torque.

[0031] For example, consider the case where the vehicle speed and target braking force are at point A. The sum of the regenerative braking and ASC torque is insufficient for the target braking force. Therefore, the shortfall becomes the braking force required for the hydraulic brake 30. Next, consider the case where the vehicle speed and target braking force are at point B. The regenerative braking is insufficient for the target braking force. However, the total braking force of the regenerative braking and ASC torque exceeds the target braking force. In this case, the electric vehicle 11 uses the regenerative braking to its upper limit, and the remaining torque becomes the braking force required for the hydraulic brake 30. Next, consider the case where the vehicle speed and target braking force are at point C. The regenerative braking exceeds the target braking force. Therefore, the electric vehicle 11 uses the regenerative braking until the target braking force is reached, and does not use the ASC torque by ASC control or the hydraulic brake 30.

[0032] An example of the operation flow of the control device 10 configured as described above will be explained using FIG. 5. As a premise, the control device 10 is configured to be able to refer to physical property data of the regenerative brake torque upper limit and ASC torque regarding the speed and braking force according to the characteristics of the electric vehicle 11 in advance. The physical property data of the regenerative brake torque upper limit and ASC torque may be stored in the control device 10 itself, or may be stored in a separate storage unit and be able to be called up as needed. The control device 10 also continues to acquire the vehicle speed of the electric vehicle 11 from the speedometer. This is in order to calculate the regenerative brake upper limit.

[0033] First (S101), the control device 10 starts acquiring the temperature of the battery 14 using the temperature acquisition unit (thermometer 32) upon starting operation (S102). The control device 10 continues these processes until operation ends. Next, the control device 10 compares the current temperature acquired from the temperature acquisition unit with a preset predetermined temperature. If the control device 10 determines that the current temperature is equal to or higher than the predetermined temperature, it determines that there is no need to heat the battery 14 (S103→No). Thereafter, the control device 10 continues the flow again (S104) and continues acquiring and comparing temperatures. If the control device 10 determines that the temperature is lower than the predetermined temperature, it determines that the environment requires control to heat the battery 14 (S103→Yes). However, if the control device 10 determines that the foot brake is not operated (S105→No), there is no need to brake, so it continues acquiring and comparing temperatures (S106).

[0034] Next, if the control device 10 determines that the foot brake is being operated, it determines the share of torque borne by the brake (S105→Yes). Next, the control device 10 calculates a target braking force, which is the required brake torque, according to the operation (amount of depression) of the foot brake (S111). Note that variables and maps according to the characteristics of the electric vehicle 11, including the foot brake, are stored in the control device 10 or in an ECU of the electric vehicle 11 provided separately. The control device 10 may refer to these to calculate the target braking force. Then, the control device 10 compares the calculated target braking force with the upper limit of the regenerative braking torque at the vehicle speed obtained from the speedometer (S112).

[0035] Next, if the control device 10 determines that the target braking force is within the upper torque limit that can be borne by the regenerative brake (S112→Yes, corresponding to C in FIG. 4), it performs regenerative charging control, which performs braking using only the regenerative brake (S113). The control device 10 continues this flow even after braking using the regenerative brake (S114). However, the upper limit of the regenerative braking torque increases as the vehicle speed decreases. Therefore, the control device 10 determines that the target braking force can be met using only the regenerative braking torque generated by the regenerative charging control, unless the foot brake is depressed and the target braking force increases.

[0036] On the other hand, if the control device 10 determines that the target braking force exceeds the regenerative brake torque upper limit (S112 → No), it calculates an estimated value of the ASC torque (ASC estimated torque) when ASC control is performed from the rotation speed of the motor 13 (S121). Note that if the sum of the regenerative brake torque upper limit and the ASC estimated torque is greater than the target braking force (S122 → Yes, corresponding to B in FIG. 4), the ASC torque cannot be adjusted, resulting in excessive torque. For this reason, the control device 10 does not perform ASC control, and instead provides braking force solely through regenerative charging control using the hydraulic brake 30 and the regenerative brake. The control device 10 then calculates the required braking force for the hydraulic brake 30 in this situation (S123). The required braking force here is the target braking force minus the regenerative brake torque upper limit. The control device 10 then performs regenerative braking until the torque reaches the upper limit (S124).

[0037] Next, the control device 10 activates the hydraulic brake 30 by the calculated required braking force (S125). After that, the control device 10 continues this flow even after braking is applied by the hydraulic brake 30 and the regenerative brake (S126). The upper limit of the regenerative brake torque increases as the vehicle speed decreases. Therefore, the control device 10 determines that the target braking force can be met by the regenerative brake alone (S112→Yes) unless the foot brake is depressed and the target braking force increases.

[0038] The reason why the control device 10 executes S125 after S124 is that the responsiveness of the hydraulic brake 30 is slower than that of the regenerative brake, and the timing at which the hydraulic brake 30 acts is likely to be delayed compared to the implementation of the regenerative brake. If the brake torques of the hydraulic brake 30 and the regenerative brake act with a time lag, a two-stage deceleration feeling will occur. To compensate for this time lag, the control device 10 preferably applies a time correction to the operation of the hydraulic brake 30. Specifically, the generation of the regenerative brake is delayed to match the timing with the generation of the brake torque of the hydraulic brake 30.

[0039] Furthermore, if the control device 10 determines that the sum of the regenerative brake torque upper limit and the ASC estimated torque is smaller than the target braking force (S122 → No), it performs ASC control and also uses the hydraulic brake 30. Therefore, the control device 10 calculates the required braking force for the hydraulic brake 30 (S131). The required braking force here is the target braking force minus the sum of the regenerative brake torque upper limit and the ASC estimated torque. The control device 10 then applies regenerative braking until the torque reaches the upper limit (S132). The control device 10 also performs ASC control and applies braking using the ASC torque (S133). The control device 10 may reverse the order of the processing of S131 to S133, or may perform them simultaneously. However, the hydraulic brake 30 has low responsiveness. Therefore, it is desirable to calculate the required braking force for the hydraulic brake 30 as soon as possible. The control device 10 then operates the hydraulic brake 30 by the calculated required braking force (S134). The control device 10 delays the generation of the regenerative brake torque and the ASC torque to match the timing with the generation of the brake torque of the hydraulic brake 30.

[0040] Here, heat generated in the motor due to ASC control is transferred to the battery 14, heating the battery 14. If this causes the current temperature of the battery 14 to rise, the control device 10 makes a negative determination in S103. Then, the control device 10 ends this processing flow.

[0041] After that, the control device 10 continues this flow even after the brakes are applied (S135). The regenerative brake torque upper limit increases as the vehicle speed decreases. Therefore, the control device 10 determines that ASC control is unnecessary unless the foot brake is depressed and the target braking force increases (S122 → Yes). If the vehicle decelerates further, the control device 10 determines that the target braking force can be met with the regenerative brakes alone (S112 → Yes).

[0042] <Using warm-up devices other than batteries> In the above flow, the heat generated by the ASC control is used to warm up the battery 14. The control device 10 may use the heat generated by the ASC control not only to warm up the battery 14 but also to warm up the cabin. In this case, the control device 10 makes the determination in S103 above by comparing not only the current temperature of the battery 14 but also the current temperature of the cabin. Even when the cabin temperature is lower than the predetermined temperature and heating is required, the control device 10 performs the ASC control and uses the heat generated.

[0043] <When there is one motor> As a second embodiment of the present invention, an example of the control of an electric vehicle 11a having one motor 13 will be described. A functional block diagram of this electric vehicle 11a is shown in Fig. 6. In the electric vehicle 11a, the motor 13a is located only on the front wheel 15a side. Furthermore, the inverter 16a connecting the battery 14 and the motor 13a is also located only on the front wheel 15a side.

[0044] In this embodiment, the control device 10 acquires the state of charge of the battery 14 using a voltmeter 31 attached to the battery 14. The control device 10 checks the acquired state of charge, and if it determines that the state of charge is equal to or greater than a predetermined value, it executes ASC control as shown in FIG. 7. On the other hand, if it determines that the state of charge is less than the predetermined value, it switches to execute regenerative charging control as shown in FIG. 8. In other words, when the state of charge is low, the control device 10 prioritizes restoring the state of charge through regeneration over converting energy into heat through ASC control.

[0045] Although not shown, in this embodiment, a thermometer 32 may be attached to the battery 14 to monitor the temperature of the battery 14. In this case, the control device 10 may perform ASC control and warm-up control when it determines that the temperature of the battery 14 is below a predetermined temperature. This is because, except when the charging rate is extremely low, the battery 14 cannot perform its full performance at extremely low temperatures, and therefore, in some cases, it may be better to prioritize heating the battery 14 over restoring the charging rate.

[0046] In this embodiment, the predetermined value for the charging rate is set to 80% or more. This value may be optimized based on the total capacity of the battery 14. The predetermined temperature may be set to a range of -10°C or less. This value may be optimized based on the performance of the battery 14.

[0047] <When there are three or more motors> A third embodiment of the present invention will be described below, which illustrates a vehicle with three or more motors 13. For example, the front wheels 15a are connected via an open differential and driven by one motor 13, while the rear wheels 15b each have a motor 13 on each side, resulting in three motors. In this case, there are three combinations of motors 13 and inverters 16 connected to the motors 13. The control device 10 performs regenerative charging control using at least one of the combinations and performs ASC control using the remaining combinations. In this case, it is desirable for the control device 10 to perform regenerative charging control using at least one combination of motor 13 and inverter 16. This is because not being able to recover regenerative power through regenerative charging control is disadvantageous in terms of energy efficiency. On the other hand, the control device 10 lowers the priority of ASC control when the temperature of the battery 14 is high. However, if there are three or more combinations, the control device 10 may continue to perform ASC control for at least one of the combinations. Furthermore, the combination of wheel 15 and inverter 16 heats up when ASC control is performed. Therefore, the control device 10 may switch the combination of executing the regenerative charging control and the ASC control at a fixed time or under fixed conditions to prevent excessive heat.

[0048] When a motor 13 is provided on each of the four wheels, regenerative charging control is similarly performed for at least one combination of motor 13 and inverter 16, and ASC control is performed for the remaining combinations. [Explanation of symbols]

[0049] 10 Control device 11, 11a Electric vehicles 13 Motor 13a Front wheel motor 13b Rear wheel motor 14 Battery 15 wheels 15a front wheel 15b rear wheel 16a Front wheel motor inverter 16b Rear wheel motor inverter 18 Diode 19 Switch 20 Heat Transfer Device 21a,21b Heat exchanger 22a, 22b flow path 23a, 23b Fluid switch 24 Radiator 30, 30a, 30b Hydraulic brake 31 Voltmeter 32 Thermometer

Claims

1. A control device for use in a vehicle, the control device including a battery, a motor, an inverter connected to the motor, and a heat transfer device capable of transferring heat between the battery and the motor using a fluid as a medium, The inverter can be selectively switched between ASC control and regenerative charging control, a control device that performs warm-up control for the motor connected to the inverter that is performing the ASC control, by using the heat transfer device to transfer heat from the motor and the inverter to the battery;

2. the vehicle has hydraulic brakes; The control device When the ASC control is being performed, the ASC torque generated by the ASC control is subtracted from the target braking force during braking to calculate a required braking force for the hydraulic brake, When the regenerative charging control is being executed, the required braking force is calculated by subtracting the braking force due to the regenerative charging control from the target braking force during braking. The control device according to claim 1 .

3. the vehicle has a plurality of combinations of the motor and the inverter, the control device executes the regenerative charge control using at least one of the plurality of motors and inverters, executes the ASC control using the remaining of the plurality of motors and inverters, and transfers heat by circulating the fluid between the remaining motor and the battery. The control device according to claim 1 or 2.

4. the vehicle has one motor, The vehicle acquires a charging rate of the battery, The control device executes the ASC control if the charging rate is equal to or higher than a predetermined value, and executes the regenerative charging control if the charging rate is lower than the predetermined value. The control device according to claim 1 or 2.

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