electric vehicles

Abstract

To suppress occurrence of relatively large imbalance between temperature of a first motor and temperature of a second motor, and between temperature of a first inverter and temperature of a second inverter.SOLUTION: An electric vehicle selects and performs a charge mode, based on at least one of temperature of first and second motors and temperature of first and second inverters, between a first charge mode where power supplied from an external power supply device to a first neutral point of the first motor is supplied through the first motor and the first inverter to a power storage device and a second charge mode where power supplied from the external power supply device to a second neutral point of the second motor is supplied through the second motor and the second inverter to the power storage device.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to electric vehicles. [Background technology]

[0002] Conventionally, an electric vehicle has been proposed that includes a power storage device, a motor having a three-phase coil, an inverter that converts DC power from the power storage device into three-phase AC power and supplies the AC power to the motor, and a control device that controls the inverter (see, for example, Patent Document 1). In this electric vehicle, during external charging in which power supplied from an external power supply device to the neutral point of the motor is supplied to the power storage device via the motor and the inverter, the control device sets a duty value of a switching element of the inverter to control the inverter. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] US Patent Application Publication No. 2020 / 0177014 Summary of the Invention [Problem to be solved by the invention]

[0004] An electric vehicle may also include a power storage device, first and second motors each having a three-phase coil, and first and second inverters that convert DC power from the power storage device into three-phase AC power and supply it to the first and second motors. In this case, if the electric vehicle continues to use only one of the first motor and first inverter and the second motor and second inverter during external charging, a relatively large imbalance in temperature between the two may occur.

[0005] The electric vehicle of the present disclosure has a primary object to prevent a relatively large imbalance from occurring between the temperature of the first motor and the temperature of the second motor, and between the temperature of the first inverter and the temperature of the second inverter. [Means for solving the problem]

[0006] The electric vehicle of the present disclosure employs the following measures to achieve the above-mentioned main object.

[0007] The electric vehicle disclosed herein is an electric vehicle including a power storage device, first and second motors each having a three-phase coil, first and second inverters that convert DC power from the power storage device into three-phase AC power and supply it to the first and second motors, and a control device that controls the first and second inverters, and the control device selects and executes a charging mode based on at least one of the temperatures of the first and second motors and the temperatures of the first and second inverters from a first charging mode in which power supplied from an external power supply device to a first neutral point of the first motor is supplied to the power storage device via the first motor and the first inverter, and a second charging mode in which power supplied from the external power supply device to a second neutral point of the second motor is supplied to the power storage device via the second motor and the second inverter.

[0008] In the electric vehicle disclosed herein, the control device selects and executes a charge mode from a first charge mode in which electric power supplied from an external power supply device to a first neutral point of the first motor is supplied to the power storage device via the first motor and the first inverter, and a second charge mode in which electric power supplied from an external power supply device to a second neutral point of the second motor is supplied to the power storage device via the second motor and the second inverter, based on at least one of the temperatures of the first and second motors and the temperatures of the first and second inverters. This makes it possible to suppress a relatively large imbalance between the temperatures of the first motor and the second motor and the temperatures of the first inverter and the second inverter in the electric vehicle, compared to when the control device always sets the charge mode to the first charge mode and when the control device always sets the charge mode to the second charge mode.

[0009] In the electric vehicle of the present disclosure, when the charging mode is the first charging mode and a value obtained by subtracting the temperature of the second motor from the temperature of the first motor reaches or exceeds a first threshold value, or when the charging mode is the first charging mode and a value obtained by subtracting the temperature of the second inverter from the temperature of the first inverter reaches or exceeds a second threshold value, the control device may switch the charging mode to the second charging mode, and when the charging mode is the second charging mode and a value obtained by subtracting the temperature of the first motor from the temperature of the second motor reaches or exceeds a third threshold value, or when the charging mode is the second charging mode and a value obtained by subtracting the temperature of the first inverter from the temperature of the second inverter reaches or exceeds a fourth threshold value, the control device may switch the charging mode to the first charging mode.

[0010] In the electric vehicle of the present disclosure, when the charging mode is the first charging mode and the temperature of the first motor reaches or exceeds a first threshold value, or when the charging mode is the first charging mode and the temperature of the first inverter reaches or exceeds a second threshold value, the control device may switch the charging mode to the second charging mode, and when the charging mode is the second charging mode and the temperature of the second motor reaches or exceeds a third threshold value, or when the charging mode is the second charging mode and the temperature of the second inverter reaches or exceeds a fourth threshold value, the control device may switch the charging mode to the first charging mode.

[0011] The electric vehicle of the present disclosure may include a cooling device that circulates a cooling medium through one or both of a first flow path including the first motor and the first inverter and a second flow path including the second motor and the second inverter, wherein when the charging mode is the first charging mode, the control device circulates the cooling medium only through the first flow path of the first and second flow paths, and when the charging mode is the second charging mode, the control device circulates the cooling medium only through the second flow path of the first and second flow paths. In this case, when the charging mode has continued in the first charging mode for a first predetermined time, the control device may switch the charging mode to the second charging mode, and when the charging mode has continued in the second charging mode for a second predetermined time, the control device may switch the charging mode to the first charging mode. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic diagram illustrating the configuration of an electric vehicle and a charging station. [Figure 2] FIG. 1 is a schematic diagram illustrating the configuration of an electric vehicle and a charging station. [Figure 3] 4 is a flowchart showing an example of an external charging control routine. [Figure 4] 4 is a flowchart showing an example of an external charging control routine. [Figure 5] 4 is a flowchart showing an example of an external charging control routine. [Figure 6] 4 is a flowchart showing an example of an external charging control routine. DETAILED DESCRIPTION OF THE INVENTION

[0013] An embodiment of the present disclosure will be described with reference to the drawings. Figures 1 and 2 are schematic configuration diagrams of an electric vehicle 20 and a charging stand 80 serving as an external power supply device according to this embodiment. As shown in Figures 1 and 2, the electric vehicle 20 includes motors 22 and 32, inverters 24 and 34, a battery 40 serving as a power storage device, an equipment-side connector 44, relays 50 and 52, a cooling device 60, and a vehicle electronic control unit (vehicle ECU) 70.

[0014] The motors 22 and 32 are each configured as a three-phase AC motor. Each of the motors 22 and 32 includes a rotor with a permanent magnet embedded in the rotor core and a stator with a three-phase coil wound around the stator core. The connections of the three-phase coils of the motors 22 and 32 form neutral points 22n and 32n (first and second neutral points), respectively. The rotors of the motors 22 and 32 are incorporated into the left and right drive wheels, respectively. In this embodiment, the motors 22 and 32 have the same rated values ​​(specifications).

[0015] The inverters 24 and 34 are connected to the battery 40 via a positive line 42a and a negative line 42b of the power line 42. The inverter 24 has six transistors T11 to T16 as switching elements and six diodes D11 to D16. The transistors T11 to T16 are arranged in pairs, two of them on the source side and the sink side of the positive line 42a and the negative line 42b, respectively. Each of the three-phase coils of the motor 22 is connected to a connection point between two of the paired transistors T11 to T16. The six diodes D11 to D16 are connected in parallel to each of the six transistors T11 to T16. The inverter 24 converts DC power from the battery 40 into three-phase AC power and supplies it to the motor 22. The inverter 34 has a similar configuration to the inverter 24. The inverter 34 has six transistors T21 to T26 and six diodes D11 to D16. The inverter 34 converts DC power from the battery 40 into three-phase AC power and supplies it to the motor 32. A capacitor 43 is connected to the positive electrode side line 42a and the negative electrode side line 42b. In this embodiment, the inverters 24, 34 have the same rated value (specification).

[0016] The battery 40 is configured as, for example, a lithium-ion secondary battery or a nickel-metal hydride secondary battery. As described above, the battery 40 is connected to the inverters 24, 34 via the positive line 42a and the negative line 42b. The equipment-side connector 44 is configured to be connectable to the stand-side connector 84 of the charging stand 80. The equipment-side connector 44 is connected to the neutral points 22n, 32n of the motors 22, 32 via the positive line 46a of the power line 46 and the relays 50, 52. The equipment-side connector 44 is also connected to the negative line 42b via the negative line 46b of the power line 46. A capacitor 47 is connected between the positive line 46a and the negative line 46b.

[0017] Relays 50, 52 respectively connect and disconnect neutral points 22n, 32n of motors 22, 32 to and from positive line 46a by being turned on and off. When relay 50 is on, a three-phase boost converter is formed by motor 22 and inverter 24 between positive line 46a and negative line 46b of power line 46 and positive line 42a and negative line 42b of power line 42. When relay 52 is on, a three-phase boost converter is formed by motor 32 and inverter 34 between positive line 46a and negative line 46b of power line 46 and positive line 42a and negative line 42b of power line 42.

[0018] The cooling device 60 includes a circulation flow path 61, a switch 62, a radiator 63, and an electric pump 64. The circulation flow path 61 includes a first flow path 61a, a second flow path 61b, and a third flow path 61c. The first flow path 61a is a flow path for circulating the coolant from the switch 62 to the junction 61d via the inverter 24 and the motor 22. The second flow path 61b is a flow path for circulating the coolant from the switch 62 to the junction 61d via the inverter 34 and the motor 32. The third flow path 61c is a flow path for circulating the coolant from the junction 61d to the switch 62 via the radiator 63 and the electric pump 64. The switch 62 is configured to be able to switch the flow of the coolant between three ways: both the first flow path 61a and the second flow path 61b, only the first flow path 61a, or only the second flow path 61b. The electric pump 64 pumps the coolant through the third flow path 61c.

[0019] The vehicle ECU 70 includes a microcomputer. The microcomputer has a CPU, ROM, RAM, flash memory, input / output ports, and communication ports. The vehicle ECU 70 receives signals from various sensors. For example, the vehicle ECU 70 receives the rotational positions of the rotors of the motors 22 and 32 from rotational position sensors and the phase currents of the motors 22 and 32 from current sensors. The vehicle ECU 70 receives temperatures αm1 and αm2 of the motors 22 and 32 from temperature sensors 22t and 32t, and temperatures αi1 and αi2 of the inverters 24 and 34 from temperature sensors 24t and 34t. The vehicle ECU 70 also receives the voltage Vb of the battery 40 from a voltage sensor 40v, the current Ib of the battery 40 from a current sensor 40i, and the temperature αb of the battery 40 from a temperature sensor 40t. The vehicle ECU 70 also receives inputs of the voltage Vc of the capacitor 47 from the voltage sensor 47a and the coolant temperature αw, which is the temperature of the coolant in the circulation flow path 61 (third flow path 61c), from the water temperature sensor 65.

[0020] The vehicle ECU 70 outputs various control signals. For example, the vehicle ECU 70 outputs control signals to transistors T11 to T16 and T21 to T26 of the inverters 24 and 34, control signals to relays 50 and 52, and control signals to the electric pump 64. The vehicle ECU 70 calculates the electrical angle θe and rotation speed Nm of the motor 22 based on the rotational position of the rotor of the motor 22. The vehicle ECU 70 calculates the power storage rate SOC of the battery 40 based on the integrated value of the current Ib of the battery 40. The vehicle ECU 70 sets an input limit Win, which is the allowable input power of the battery 40, based on the power storage rate SOC of the battery 40 and the temperature αb of the battery 40. The vehicle ECU 70 is capable of communicating with an electronic control unit (stand ECU) 88 of a charging stand 80 at home, at a charging station, or the like.

[0021] The charging stand 80 is installed at a home, a charging station, or the like. The charging stand 80 includes a power supply device 82, a stand connector 84, and a stand ECU 88. The power supply device 82 is connected to the stand connector 84 via a positive line 86a and a negative line 86b of a power line 86. The power supply device 82 is configured to convert AC power from the power grid into DC power and to output the DC power after adjusting the output voltage and power. The stand connector 84 is configured to be connectable to the equipment connector 44 of the electric vehicle 20. When the stand connector 84 and the equipment connector 44 are connected, the positive line 86a and the positive line 46a, and the negative line 86b and the negative line 46b are connected, respectively.

[0022] The stand ECU 88 includes a microcomputer. The microcomputer has a CPU, ROM, RAM, flash memory, input / output ports, and communication ports. The stand ECU 88 receives the output voltage Vs of the power supply device 82 from a voltage sensor 83v and the output current Is of the power supply device 82 from a current sensor 83i. The stand ECU 88 outputs a control signal to the power supply device 82. The stand ECU 88 calculates the output power Ps based on the output voltage Vs and the output current Is. The stand ECU 88 is capable of communicating with the vehicle ECU 70 of the electric vehicle 20.

[0023] Next, the operation of the electric vehicle 20 will be described. In particular, the operation during external charging will be described. External charging is charging the battery 40 using power from a power supply device 82 of a charging stand 80. In this embodiment, the electric vehicle 20 performs external charging while switching the charging mode between a first charging mode and a second charging mode. In the first charging mode, power supplied from the power supply device 82 to the neutral point 22n of the motor 22 is supplied to the battery 40 via the motor 22 and the inverter 24. In the second charging mode, power supplied from the power supply device 82 to the neutral point 32n of the motor 22 is supplied to the battery 40 via the motor 32 and the inverter 34.

[0024] 3 is a flowchart showing an example of an external charging control routine executed by the vehicle ECU 70. This routine is executed when a charging start condition is met while the equipment-side connector 44 and the station-side connector 84 are connected. The charging start condition may be, for example, a condition in which a user issues an instruction to start charging the battery 40. When this routine starts, both relays 50 and 52 are off. During execution of this routine, the vehicle ECU 70 controls the switch 62 and the electric pump 64 so that the coolant flows through both the first flow path 61a and the second flow path 61b.

[0025] 3 is executed, the vehicle ECU 70 selects the first charging mode (step S100). The vehicle ECU 70 turns on the relay 50 (step S102). The vehicle ECU 70 sets the target power Ps* and transmits it to the stand ECU 88 (step S104). The vehicle ECU 70 controls the drive of the inverter 24 (step S106). The target power Ps* is set, for example, within the range of the input limit Win of the battery 40. The stand ECU 88 controls the power supply device 82 so that the output power Ps becomes the target power Ps*. In the drive control of the inverter 24, the duties of the transistors T11 to T16 are set based on the voltage ratio between the voltage Vb of the battery 40 and the voltage Vc of the capacitor 47.

[0026] The vehicle ECU 70 receives input of temperatures αm1 and αm2 of the motors 22 and 32 (step S110). The vehicle ECU 70 determines whether the charging mode is the first charging mode or the second charging mode (step S120). When the charging mode is the first charging mode, the vehicle ECU 70 compares a value (αm1-αm2) obtained by subtracting the temperature αm2 of the motor 32 from the temperature αm1 of the motor 22 with a threshold value Δαmref1 (step S130). When the value (αm1-αm2) is less than the threshold value Δαmref1, the vehicle ECU 70 determines to maintain the charging mode. In this case, the vehicle ECU 70 sets a target power Ps* and transmits it to the station ECU 88 (step S132). The vehicle ECU 70 controls the drive of the inverter 24 (step S134). The vehicle ECU 70 determines whether a charging stop condition is met (step S170). The charging stop condition is, for example, an OR condition such as a condition that the power storage percentage SOC of the battery 40 reaches or exceeds a threshold value Sth, or a condition that the user issues an instruction to stop charging the battery 40. If the charging stop condition is not satisfied in step S170, the vehicle ECU 70 returns to the processing of step S110.

[0027] When the value (αm1-αm2) is equal to or greater than the threshold value Δαmref1 in step S130, the vehicle ECU 70 determines that the charging mode needs to be switched to the second charging mode (step S140). In this case, the vehicle ECU 70 executes a first stop process (step S142). In the first stop process, the vehicle ECU 70 stops driving the inverter 24 and transmits a power interruption command to the station ECU 88. The station ECU 88 temporarily stops the power supply device 82. This temporarily stops external charging. The vehicle ECU 70 turns off the relay 50 and turns on the relay 52 (step S144). The vehicle ECU 70 sets a target power Ps* and transmits it to the station ECU 88 (step S152). The vehicle ECU 70 controls the driving of the inverter 34 (step S154) and proceeds to the process of step S170. In the drive control of the inverter 34, the duties of the transistors T21 to T26 are set based on the voltage ratio between the voltage Vb of the battery 40 and the voltage Vc of the capacitor 47. By shifting the charging mode to the second charging mode, the electric vehicle 20 can suppress a further increase in the temperature αm1 of the motor 22. As a result, the electric vehicle 20 can suppress the occurrence of a relatively large imbalance between the temperature αm1 of the motor 22 and the temperature αm2 of the motor 32.

[0028] If the charging mode is the second charging mode in step S120, the vehicle ECU 70 compares the value (αm2-αm1) obtained by subtracting the temperature αm1 of the motor 22 from the temperature αm2 of the motor 32 with a threshold value Δαmref2 (step S150). The threshold value Δαmref2 may be the same as the threshold value Δαmref1, for example. If the value (αm2-αm1) is less than the threshold value Δαmref2, the vehicle ECU 70 determines that the charging mode should be maintained. In this case, the vehicle ECU 70 sets a target power Ps* and transmits it to the stand ECU 88 (step S152). The vehicle ECU 70 controls the drive of the inverter 34 (step S154) and proceeds to the processing of step S170.

[0029] When the value (αm2-αm1) is equal to or greater than the threshold value Δαmref2 in step S150, the vehicle ECU 70 determines that the charging mode needs to be switched to the first charging mode (step S160). In this case, the vehicle ECU 70 executes a second stop process (step S162). In the second stop process, the vehicle ECU 70 stops driving the inverter 34 and transmits a power interruption command to the station ECU 88. The station ECU 88 temporarily stops the power supply device 82. This temporarily stops external charging. The vehicle ECU 70 turns off the relay 52 and turns on the relay 50 (step S164). The vehicle ECU 70 sets a target power Ps* and transmits it to the station ECU 88 (step S132). The vehicle ECU 70 controls the driving of the inverter 24 (step S134) and proceeds to the process of step S170. By shifting the charging mode to the first charging mode, electric vehicle 20 can suppress a further increase in temperature αm2 of motor 32. As a result, electric vehicle 20 can suppress the occurrence of a relatively large imbalance between temperature αm1 of motor 22 and temperature αm2 of motor 32.

[0030] If the charging stop condition is met in step S170, the vehicle ECU 70 executes a final stop process (step S172) and ends this routine. In the final stop process, the vehicle ECU 70 stops driving one of the inverters 24, 34 that is currently being driven, and sends a power end command to the station ECU 88. The station ECU 88 stops the power supply device 82. This ends external charging.

[0031] In the electric vehicle 20 of the present embodiment described above, when the charge mode is the first charge mode and the value (αm1 - αm2) reaches or exceeds the threshold value Δαmref1, the vehicle ECU 70 switches the charge mode to the second charge mode. Also, when the charge mode is the second charge mode and the value (αm2 - αm1) reaches or exceeds the threshold value Δαmref2, the vehicle ECU 70 switches the charge mode to the first charge mode. This makes it possible to prevent a relatively large imbalance from occurring between the temperature αm1 of the motor 22 and the temperature αm2 of the motor 32. As a result, it is possible to prevent a relatively large imbalance from occurring between the driving performance of the motor 22 and the driving performance of the motor 32 when the electric vehicle 20 subsequently travels.

[0032] Instead of the processing of step S130 in the above-described embodiment, the vehicle ECU 70 may compare the value (αi1-αi2) obtained by subtracting the temperature αi2 of the inverter 34 from the temperature αi1 of the inverter 24 with the threshold value Δαiref1. That is, when the value (αi1-αi2) is less than the threshold value Δαiref1, the vehicle ECU 70 may maintain the charging mode, and when the value (αi1-αi2) is equal to or greater than the threshold value Δαiref1, the vehicle ECU 70 may switch the charging mode to the second charging mode. Also, instead of the processing of step S150, the vehicle ECU 70 may compare the value (αi2-αi1) obtained by subtracting the temperature αi1 of the inverter 24 from the temperature αi2 of the inverter 34 with the threshold value Δαiref2. That is, when the value (αi2-αi1) is less than the threshold value Δαiref2, the vehicle ECU 70 may maintain the charging mode, and when the value (αi2-αi1) is equal to or greater than the threshold value Δαiref2, the vehicle ECU 70 may switch the charging mode to the first charging mode. The threshold values ​​Δαierf1 and Δαiref2 may be the same value, for example. This makes it possible to prevent a relatively large imbalance between the temperature αi1 of the inverter 24 and the temperature αi2 of the inverter 34.

[0033] Instead of the external charging control routine of Fig. 3 in the above-described embodiment, the vehicle ECU 70 may execute an external charging control routine of Fig. 4. The external charging control routine of Fig. 4 differs from the external charging control routine of Fig. 3 in that the processes of steps S130 and S150 are replaced with the processes of steps S130b and S150b. In the external charging control routine of Fig. 4, when the charging mode is the first charging mode in step S120, the vehicle ECU 70 compares the temperature αm of the motor 22 with a threshold value αmref1 (step S130b). When the temperature αm1 of the motor 22 is less than the threshold value αmref1, the vehicle ECU 70 determines that the charging mode should be maintained and proceeds to the process of step S132. On the other hand, when the temperature αm1 of the motor 22 is equal to or greater than the threshold value αmref1, the vehicle ECU 70 determines that the charging mode needs to be switched to the second charging mode (step S140) and proceeds to the process of step S142. In this case, similar to the above-described embodiment, by shifting from the charging mode to the second charging mode, electric vehicle 20 can suppress a further increase in temperature αm1 of motor 22. As a result, electric vehicle 20 can suppress a relatively large imbalance between temperature αm1 of motor 22 and temperature αm2 of motor 32.

[0034] When the charging mode is the second charging mode in step S120, the vehicle ECU 70 compares the temperature αm of the motor 32 with a threshold value αmref2 (step S150b). The threshold value Δαmref2 may be the same as the threshold value Δαmref1, for example. When the temperature αm2 of the motor 32 is less than the threshold value αmref2, the vehicle ECU 70 determines that the charging mode should be maintained and proceeds to the processing of step S152. On the other hand, when the temperature αm2 of the motor 32 is equal to or greater than the threshold value αmref2, the vehicle ECU 70 determines that the charging mode needs to be switched to the first charging mode (step S140) and proceeds to the processing of step S162. In this case, as in the above-described embodiment, by switching the charging mode to the first charging mode, the electric vehicle 20 can suppress a further increase in the temperature αm2 of the motor 32. As a result, the electric vehicle 20 can suppress a relatively large imbalance between the temperature αm1 of the motor 22 and the temperature αm2 of the motor 32.

[0035] 4, the vehicle ECU 70 may compare the temperature αi1 of the inverter 24 with the threshold value αiref1. That is, when the temperature αi1 of the inverter 24 is less than the threshold value αiref1, the vehicle ECU 70 may maintain the charging mode, and when the temperature αi1 of the inverter 24 is equal to or greater than the threshold value αiref1, the vehicle ECU 70 may switch the charging mode to the second charging mode. Also, instead of the processing of step S150b, the vehicle ECU 70 may compare the temperature αi2 of the inverter 34 with the threshold value αiref2. That is, when the temperature αi2 of the inverter 34 is less than the threshold value αiref2, the vehicle ECU 70 may maintain the charging mode, and when the temperature αi2 of the inverter 34 is equal to or greater than the threshold value αiref2, the vehicle ECU 70 may switch the charging mode to the first charging mode. The threshold values ​​αiref1 and αiref2 may, for example, be the same value. This makes it possible to prevent a relatively large imbalance from occurring between the temperature αi1 of the inverter 24 and the temperature αi2 of the inverter 34.

[0036] Instead of the external charging control routine of FIG. 3 in the above-described embodiment, the vehicle ECU 70 may execute an external charging control routine of FIG. 5. The external charging control routine of FIG. 5 differs from the external charging control routine of FIG. 3 in that the processes of steps S103, S146, and S166 are added. In the external charging control routine of FIG. 5, when the vehicle ECU 70 turns on the relay 50 in step S102, the vehicle ECU 70 starts executing the first flow control. In the first flow control, the vehicle ECU 70 controls the switch 62 and the electric pump 64 so that the coolant flows only through the first flow path 61a out of the first flow path 61a and the second flow path 61b. That is, in the first charging mode, the vehicle ECU 70 executes the first flow control. This allows the electric vehicle 20 to suppress temperature increases in the motor 22 and the inverter 24.

[0037] When the vehicle ECU 70 turns off the relay 50 and turns on the relay 52 in step S144, the vehicle ECU 70 switches from the first flow control to the second flow control (step S146) and proceeds to the process of step S152. In the second flow control, the vehicle ECU 70 controls the switch 62 and the electric pump 64 so that the coolant flows only through the second flow path 61b out of the first flow path 61a and the second flow path 61b. That is, in the second charging mode, the vehicle ECU 70 executes the second flow control. This allows the electric vehicle 20 to suppress temperature increases in the motor 32 and the inverter 34. When the vehicle ECU 70 turns off the relay 52 and turns on the relay 50 in step S164, the vehicle ECU 70 switches from the second flow control to the first flow control (step S166) and proceeds to the process of step S132.

[0038] Instead of the external charging control routine of Fig. 5, the vehicle ECU 70 may execute an external charging control routine of Fig. 6. The external charging control routine of Fig. 6 differs from the external charging control routine of Fig. 5 in that the processes of steps S131 and S151 are added. In the external charging control routine of Fig. 6, when the charging mode is the first charging mode in step S120 and the value (αm1-αm2) is less than the threshold value Δαmref1 in step S130, the vehicle ECU 70 determines whether the charging mode has continued in the first charging mode for a predetermined time T1 (step S131). When the charging mode has not continued in the first charging mode for the predetermined time T1, the vehicle ECU 70 determines that the charging mode is maintained and proceeds to the process of step S132. On the other hand, when the charging mode has continued in the first charging mode for the predetermined time T1, the vehicle ECU 70 determines that the charging mode needs to be switched to the second charging mode (step S140) and proceeds to the process of step S142. This prevents the first charging mode from continuing for an excessively long time.

[0039] When the charging mode is the second charging mode in step S120 and the value (αm2-αm1) is less than the threshold value Δαmref2 in step S150, the vehicle ECU 70 determines whether the charging mode has continued in the second charging mode for a predetermined time T2 (step S151). When the charging mode has not continued in the second charging mode for the predetermined time T2, the vehicle ECU 70 determines that the charging mode is maintained and proceeds to processing in step S152. On the other hand, when the charging mode has continued in the second charging mode for the predetermined time T2, the vehicle ECU 70 determines that the charging mode needs to be switched to the first charging mode (step S160) and proceeds to processing in step S162. The predetermined time T2 is, for example, the same time as the predetermined time T1. This prevents the second charging mode from continuing for an excessively long time.

[0040] Instead of the processing of steps S130 and S130b of the external charging control routine of FIGS. 3 to 6, the vehicle ECU 70 may switch the charging mode to the second charging mode when at least one of first to fourth conditions is met. The first condition is that the value (αm1-αm2) is equal to or greater than the threshold value Δαmref1. The second condition is that the value (αi1-αi2) is equal to or greater than the threshold value Δαiref1. The third condition is that the temperature αm1 of the motor 22 is equal to or greater than the threshold value αmref1. The fourth condition is that the temperature αi1 of the inverter 24 is equal to or greater than the threshold value αiref1. Instead of the processing of steps S150 and S150b, the vehicle ECU 70 may switch the charging mode to the first charging mode when at least one of fifth to eighth conditions is met. The fifth condition is that the value (αm2-αm1) is equal to or greater than the threshold value Δαmref2. The sixth condition is that the value (αi2-αi1) is equal to or greater than the threshold value Δαiref2. The seventh condition is that the temperature αm2 of the motor 32 is equal to or greater than the threshold value αmref2. The eighth condition is that the temperature αi2 of the inverter 34 is equal to or greater than the threshold value αiref2.

[0041] In the above-described embodiment, the motors 22 and 32 may be used to drive the front and rear drive wheels, respectively, instead of being used to drive the left and right drive wheels, respectively.

[0042] In the above-described embodiment, instead of the battery 40 being used as the power storage device, a capacitor may be used.

[0043] In the above-described embodiment, instead of the electric vehicle 20 having the motors 22, 32, the vehicle may be a hybrid vehicle having the motors 22, 32 and an engine, or a fuel cell vehicle having the motors 22, 32 and a fuel cell mounted thereon.

[0044] The above describes embodiments for implementing the present disclosure, but the present disclosure is not limited to these embodiments and can, of course, be implemented in various forms within the scope that does not deviate from the gist of the present disclosure. [Industrial Applicability]

[0045] The present disclosure is applicable to the electric vehicle manufacturing industry and the like. [Explanation of symbols]

[0046] 20 Electric vehicle, 22,32 Motor, 22n,32n Neutral point, 22t,24t,32t,34t Temperature sensor, 24,34 Inverter, 40 Battery, 50,52 Relay, 60 Cooling device, 70 Vehicle ECU, 80 Charging station.

Claims

1. An electric vehicle including a power storage device, first and second motors each having a three-phase coil, first and second inverters that convert DC power from the power storage device into three-phase AC power and supply the three-phase AC power to the first and second motors, and a control device that controls the first and second inverters, the control device selects and executes a charging mode from a first charging mode in which power supplied from an external power supply device to a first neutral point of the first motor is supplied to the power storage device via the first motor and the first inverter, and a second charging mode in which power supplied from the external power supply device to a second neutral point of the second motor is supplied to the power storage device via the second motor and the second inverter, based on at least one of temperatures of the first and second motors and temperatures of the first and second inverters; The control device when the charging mode is the first charging mode and a value obtained by subtracting the temperature of the second motor from the temperature of the first motor reaches a first threshold value or more, or when the charging mode is the first charging mode and a value obtained by subtracting the temperature of the second inverter from the temperature of the first inverter reaches a second threshold value or more, the charging mode is switched to the second charging mode; when the charging mode is the second charging mode and a value obtained by subtracting the temperature of the first motor from the temperature of the second motor reaches a third threshold value or more, or when the charging mode is the second charging mode and a value obtained by subtracting the temperature of the first inverter from the temperature of the second inverter reaches a fourth threshold value or more, the charging mode is switched to the first charging mode. Electric car.

2. An electric vehicle including a power storage device, first and second motors each having a three-phase coil, first and second inverters that convert DC power from the power storage device into three-phase AC power and supply the three-phase AC power to the first and second motors, and a control device that controls the first and second inverters, the control device selects and executes a charging mode from a first charging mode in which power supplied from an external power supply device to a first neutral point of the first motor is supplied to the power storage device via the first motor and the first inverter, and a second charging mode in which power supplied from the external power supply device to a second neutral point of the second motor is supplied to the power storage device via the second motor and the second inverter, based on at least one of temperatures of the first and second motors and temperatures of the first and second inverters; The control device When the charging mode is the first charging mode and the temperature of the first motor reaches a first threshold value or more, or when the charging mode is the first charging mode and the temperature of the first inverter reaches a second threshold value or more, the charging mode is switched to the second charging mode; When the charging mode is the second charging mode and the temperature of the second motor reaches a third threshold value or higher, or when the charging mode is the second charging mode and the temperature of the second inverter reaches a fourth threshold value or higher, the charging mode is switched to the first charging mode. Electric car.

3. The electric vehicle according to claim 1 or 2, a cooling device that circulates a cooling medium through one or both of a first flow path including the first motor and the first inverter and a second flow path including the second motor and the second inverter; When the charging mode is the first charging mode, the control device causes the cooling medium to flow only through the first flow path of the first flow path and the second flow path, and when the charging mode is the second charging mode, the control device causes the cooling medium to flow only through the second flow path of the first flow path and the second flow path. Electric car.

4. The electric vehicle according to claim 3, When the charging mode continues for a first predetermined time in the first charging mode, the control device switches the charging mode to the second charging mode, and the charging mode is When the second charging mode continues for a second predetermined time, the control device switches the charging mode to the first charging mode. Electric car.

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