Vehicular motor control device and vehicular motor control method

A motor control method for a vehicle, which is carried out in a motor control device for a vehicle,

• the motor control device for a vehicle including:
• an inverter, in which a plurality of power semiconductor devices are installed, and which is configured to drive a motor through switching-control of the plurality of power semiconductor devices;
• a DC/DC converter, which has a circuit configuration in which DC/DC power conversion of stepping up an input voltage, which is a DC voltage, in accordance with a voltage command value is carried out, to thereby generate an output voltage to be applied to the inverter as a stepwise output value;
• a voltage sensor, which is configured to measure each of the input voltage and the output voltage;
• and
• a controller, which is configured to read as input information the input voltage and the output voltage, which are detected by the voltage sensor, and a torque command value to calculate the voltage command value based on the input information,
• the motor control method for a vehicle, which is carried out by the controller, comprising:
• a first step of generating the voltage command value based on the input information so that the output voltage is generated by the DC/DC converter as the stepwise output value obtained by stepping up the input voltage to an integer multiple of the input voltage;
• a second step of estimating a loss of the motor for each of a plurality of voltage command values, which is able to be output in the first step;
• a third step of estimating a loss of the inverter for each of the plurality of voltage command values;
• a fourth step of estimating a loss of the DC/DC converter for each of the plurality of voltage command values;
• and
• a fifth step of calculating a total loss, which is a sum of the respective losses for each of the plurality of voltage command values, from respective estimation results obtained in the second step, the third step, and the fourth step, identifying a voltage command value that minimizes the total loss, and outputting the identified voltage command value to the DC/DC converter.