CN-122008894-A - Electric vehicle

Abstract

The present disclosure relates to an electric vehicle. The electric vehicle includes a heat exchange system capable of transferring heat generated by a three-phase alternating-current motor to a battery, and a control device that controls heat generation control of an electric power control device such that a direct current flows through each of three-phase coils in response to establishment of a predetermined condition during stoppage of the electric vehicle, and that controls the electric power control device such that a maximum current flows through a coil of the three-phase coils having a highest degree of impregnation with respect to a cooling medium of the three-phase alternating-current motor and the maximum current rises during execution of the heat generation control. The electric vehicle can protect three-phase coils of a three-phase ac motor and generate more heat during a stop.

Inventors

• HASEBE HIROYA

Assignees

• 丰田自动车株式会社

Dates

Publication Date

20260512

Application Date

20251017

Priority Date

20241111

Claims (5)

1. 1. An electric vehicle, wherein the electric vehicle comprises: a three-phase ac motor having three-phase coils connected at a neutral point and capable of outputting power for traveling; A battery; a power control device that adjusts power from the battery and supplies the adjusted power to the three-phase ac motor; A heat exchange system capable of transferring heat generated by the three-phase AC motor to the battery, and And a control device that controls heat generation control of the electric power control device such that a direct current flows through each of the three-phase coils in response to establishment of a predetermined condition during stoppage of the electric vehicle, wherein the electric power control device is controlled such that a maximum current flows through a coil having a highest degree of impregnation with respect to a cooling medium of the three-phase alternating current motor among the three-phase coils and the maximum current is raised during execution of the heat generation control.
2. 2. The electric vehicle of claim 1, wherein, The predetermined condition is satisfied at least when the temperature of the battery is a predetermined temperature or less.
3. 3. The electric vehicle according to claim 1 or 2, wherein, The battery can be charged by electric power from an external charging device.
4. 4. The electric vehicle according to claim 1 or 2, wherein, The control means corrects an electrical angle of the three-phase alternating-current motor so that the maximum current flows in the coil having the highest degree of impregnation when the maximum current does not flow in the coil having the highest degree of impregnation among the three-phase coils after starting execution of the heat generation control.
5. 5. The electric vehicle of claim 4, wherein, The control device controls the power control device so that the maximum current does not burn the coils other than the coil having the highest degree of impregnation when the maximum current flows through the coil having the highest degree of impregnation.

Description

Electric vehicle Technical Field The present disclosure relates to an electric vehicle that includes a three-phase alternating-current motor having three-phase coils wired at a neutral point and that is capable of outputting power for running. Background Conventionally, there is known a motor control device that controls an ac motor having m stator coils wound around m teeth, each of which has one end connected to an inverter and the other end connected as a neutral point (for example, refer to patent document 1). When the temperature of p stator coils is lower than the temperature of the rest (m-p) stator coils, the motor control device flows alternating currents which are 360 DEG/p in phase shift and have equal amplitude in the p stator coils, and flows alternating currents which are 360 DEG/m-p in phase shift and have equal amplitude in the rest (m-p) stator coils. Thus, by flowing a larger amount of current through the stator coil having a lower temperature than the stator coil having a higher temperature, the coil temperature can be made uniform, and the torque of the motor as a whole can be improved. Prior art literature Patent literature Patent document 1 Japanese patent application laid-open No. 2010-206897 Disclosure of Invention In a vehicle that runs by power from an ac motor controlled by the above-described conventional motor control device, by flowing a dc current through each stator coil so that the total current flowing through m stator coils becomes zero during a stop, the ac motor can be heated and the battery can be warmed up by heat from the ac motor. In this case, however, when the current flowing through the stator coil having a low temperature is increased in order to increase the heat from the ac motor, an increased amount of current flows through the stator coil having a high temperature. Therefore, the amount of increase in current in the stator with low temperature has to be determined to prevent burnout of the coil with high temperature, etc., and it is difficult to cause the ac motor to generate a large amount of heat. In addition, in the vicinity of the stator coil having a high temperature, demagnetization may occur due to heat conduction. Accordingly, a main object of the present disclosure is to protect three-phase coils of a three-phase ac motor and to generate more heat in the three-phase ac motor during a stop of an electric vehicle. An electric vehicle of the present disclosure includes a three-phase alternating current motor, a battery, an electric power control device, a heat exchange system, and a control device. The three-phase ac motor has three-phase coils connected at a neutral point, and is capable of outputting power for traveling. The power control device adjusts power from the battery and supplies the adjusted power to the three-phase ac motor. The heat exchange system is capable of transferring heat generated by the three-phase ac motor to the battery. The control device performs heat generation control of the electric power control device such that a direct current flows through each of the three-phase coils in response to satisfaction of a predetermined condition during stoppage of the electric vehicle. Further, the control device controls the power control device so that the maximum current flows through the coil having the highest degree of impregnation with the cooling medium of the three-phase ac motor among the three-phase coils and the maximum current is increased during execution of the heat generation control. This makes it possible to prevent burnout and the like of a coil through which the largest current flows, among the three-phase coils, by cooling the coil with the cooling medium of the three-phase ac motor, prevent burnout and the like of the remaining coils through which the largest current does not flow, and promote heat generation in the three-phase ac motor by increasing the current flowing through each coil. As a result, the three-phase ac motor can be protected during the stop of the electric vehicle, and more heat can be generated by the three-phase ac motor. The heat generated by the three-phase ac motor can be transferred to the battery by the heat exchange system to preheat the battery. The predetermined condition may be satisfied at least when the temperature of the battery is equal to or lower than a predetermined temperature. Further, the battery may be chargeable by electric power from an external charging device. Further, the control device may correct the electrical angle of the three-phase ac motor so that the maximum current flows through the coil having the highest degree of impregnation, when the maximum current does not flow through the coil having the highest degree of impregnation, after starting the execution of the heat generation control. Further, the control device may control the power control device so that, when the maximum current flows through the coil having the highest degree of impregnation, the maximum curr