Patent attributes
A control device includes a gate-signal generating unit that outputs a gate signal to an inverter circuit and a voltage-vector generating unit that generates a voltage command to the gate-signal generating unit on the basis of a torque command PTR from an upper unit, rotating speed FM of an alternating-current electric motor, and a direct-current voltage value EFC applied to the inverter circuit. The voltage-vector generating unit calculates, on basis of a modulation rate, which is a ratio of the direct-current voltage value EFC and a voltage amplitude command in the voltage command, a PWM current distortion rate serving as an index representing a degree of a current harmonic caused by PWM control, generates the voltage amplitude command value on the basis of the calculated PWM current distortion rate, and outputs the voltage amplitude command value to the gate-signal generating unit.
