Included are: a voltage command generation unit which generates a voltage command amplitude and a voltage command phase based on a current command value; a phase generation unit during rectangular wave energization, which generates a voltage command phase during rectangular wave energization; and a control switching determination unit which switches by determining as to which control of PWM energization or rectangular wave energization will be performed depending on the amount of the condition of a motor. A switching device unit is driven by the output from a PWM energization unit when switched to the PWM energization; and the switching device unit is driven by the output from a rectangular wave energization unit when switched to the rectangular wave energization. The voltage command generation unit calculates the voltage command amplitude and the voltage command phase by using parameters of the motor.