Inverter control device, electric vehicle

Abstract

To effectively reduce a high-frequency loss of a motor independently of the number of PWM pulses per one cycle of electric angle.SOLUTION: An inverter control device 200 comprises: a PWM pulse generation part 230 that performs pulse width modulation of a three-phase voltage command by using a periodically varying carrier wave to generate a PWM pulse signal; and a target harmonic current calculation part 240 that calculates target harmonic currents (Idn* and Iqn*) for reducing a stator loss and a rotor loss respectively generated at a stator and a rotor of a motor 300 by a harmonic current flowing through the motor 300 according to the PWM pulse signal under a drive condition of the motor 300. The PWM pulse generation part 230 generates such a PWM pulse signal that a zero-phase voltage Vn that is a total sum of three-phase output voltages from a three-phase inverter circuit becomes non-zero, on the basis of the target harmonic currents (Idn* and Iqn*).SELECTED DRAWING: Figure 1

Claims

1. A device for controlling an inverter that converts direct current into three-phase alternating current and outputs it to a motor by driving a three-phase inverter circuit, A PWM pulse generation unit generates a PWM pulse signal for controlling the drive of the three-phase inverter circuit by pulse width modulating a three-phase voltage command using a periodically changing carrier wave, The system includes a target harmonic current calculation unit that calculates a target harmonic current to reduce stator losses and rotor losses generated in the stator and rotor of the motor, respectively, by the harmonic currents flowing through the motor in response to the PWM pulse signal, according to the driving conditions of the motor. The PWM pulse generation unit generates the PWM pulse signal based on the target harmonic current such that the zero-sequence voltage, which is the sum of the three-phase output voltages from the three-phase inverter circuit, is non-zero. This is an inverter control device.

2. In the inverter control device according to claim 1, The system includes a zero-sequence voltage command calculation unit that calculates a zero-sequence voltage command for changing the zero-sequence voltage at half-period intervals of the carrier wave based on the target harmonic current, The PWM pulse generation unit is an inverter control device that generates the PWM pulse signal based on the zero-sequence voltage command.

3. In the inverter control device according to claim 1, The system includes a target phase value calculation unit that calculates a target phase value for the phase of the PWM pulse signal based on the target harmonic current, The PWM pulse generation unit is an inverter control device that generates the PWM pulse signal based on the target phase value.

4. In the inverter control device according to claim 1, The PWM pulse generation unit generates the PWM pulse signal in an asynchronous PWM control state where the ratio of the period of the three-phase voltage command to the period of the carrier wave is a non-integer, such that the zero-sequence voltage changes in synchronization with the three-phase voltage command.

5. In the inverter control device according to claim 1, The target harmonic current calculation unit corrects the calculated target harmonic current, The PWM pulse generation unit is an inverter control device that generates the PWM pulse signal based on the corrected target harmonic current.

6. In the inverter control device according to claim 1, The PWM pulse generation unit is an inverter control device that switches the frequency of the carrier wave to a higher frequency than normal when the output torque of the motor is within a predetermined first range and the magnitude of the harmonic loss, which is the sum of the stator loss and the rotor loss, is within a predetermined second range.

7. A motor having a stator and a rotor, A battery that supplies DC current, An inverter having a three-phase inverter circuit, which converts the DC current into a three-phase AC current by driving the three-phase inverter circuit and outputs it to the motor, The system comprises an inverter control device that controls the inverter, The inverter control device is A PWM pulse generation unit generates a PWM pulse signal for controlling the drive of the three-phase inverter circuit by pulse width modulating a three-phase voltage command using a periodically changing carrier wave, The system includes a target harmonic current calculation unit that calculates a target harmonic current to reduce stator losses and rotor losses generated in the stator and rotor, respectively, by the harmonic current flowing through the motor in response to the PWM pulse signal, depending on the driving conditions of the motor. The PWM pulse generation unit generates the PWM pulse signal based on the target harmonic current such that the zero-sequence voltage, which is the sum of the three-phase output voltages from the three-phase inverter circuit, is not zero.

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