Motor controller
Provided is a technology capable of ensuring drivability of an electric vehicle while preventing thermal destruction of its parts and deterioration of a battery, caused by an LC resonance. The present specification discloses a motor controller for an electric vehicle having a battery, a converter circuit, an inverter circuit, a smoothing capacitor, and a motor, the motor controller configured to control a drive of the motor by controlling an operation of the inverter circuit. In this motor controller, an operating region of the motor that causes a resonance of an LC circuit configured by a reactor of the converter circuit and the smoothing capacitor is set as a resonance region. In this motor controller, execution of square-wave control on the motor is permitted only over a predetermined time period, when the converter circuit is not boosting the DC power and an operating point of the motor is included in the resonance region.
1. A motor controller for an electric vehicle including a battery, a converter circuit that boosts a DC power obtained from the battery, an inverter circuit that converts the DC power obtained from the converter circuit into an AC power, a smoothing capacitor provided between the converter circuit and the inverter circuit, and a motor driven by the AC power obtained from the inverter circuit, the motor controller configured to control a drive of the motor by controlling an operation of the inverter circuit,
wherein a resonance region is an operating region of the motor that causes a resonance of an LC circuit configured by a reactor of the converter circuit and the smoothing capacitor, and
wherein the motor controller is programmed to permit execution of square-wave control of the motor only within a predetermined time period in a case where the converter circuit is not boosting the DC power and an operating point of the motor is included in the resonance region and the motor controller is programmed to prohibit execution of square-wave control of the motor when outside of the predetermined time period in the case where the converter circuit is not boosting the DC power and the operating point of the motor is included in the resonance region,
wherein the predetermined time period is shorter than an amount of time needed to overheat the converter circuit or to deteriorate the battery by the resonance of the LC circuit.
2. The motor controller according to claim 1 , wherein, in the case where the converter circuit is not boosting the DC power and the operating point of the motor is included in the resonance region, the motor controller permits the execution of the square-wave control of the motor while a voltage of the battery is higher than a lower limit value, and prohibits the execution of the square-wave control of the motor once the voltage of the battery falls below the lower limit value.
3. A motor controller for an electric vehicle including a battery, a converter circuit that boosts a DC power obtained from the battery, an inverter circuit that converts the DC power obtained from the converter circuit into an AC power, a smoothing capacitor provided between the converter circuit and the inverter circuit, and a motor driven by the AC power obtained from the inverter circuit, the motor controller configured to control a drive of the motor by controlling an operation of the inverter circuit,
wherein a resonance region is an operating region of the motor that causes a resonance of an LC circuit configured by a reactor of the converter circuit and the smoothing capacitor, and
wherein, in a case where the converter circuit is not boosting the DC power and an operating point of the motor is included in the resonance region, the motor controller is programmed to permit execution of square-wave control of the motor while a voltage of the battery is higher than a lower limit value, and to prohibit the execution of the square-wave control on the motor once the voltage of the battery falls below the lower limit value.