a current control unit configured to output a voltage command value for each of three phases;

a PWM control unit configured to convert a DC voltage output from a converter into an AC voltage by modulating a pulse width of switching according to the voltage command value and apply the converted voltage to a power line of each of three phases of the three-phase motor;

one or more current detectors provided for at least one of three-phase power lines to detect the value of current flowing through the power line, as a current detection value; and

an abnormality determination unit configured to determine the presence of any abnormality in the current detector,

wherein the abnormality determination unit

calculates, as a voltage command threshold, a value obtained by adding a dead time voltage error that is a voltage error occurring due to a dead time of the switching to an ideal voltage command threshold that is a value obtained by multiplying a prescribed reference current value by a motor resistance value, and

outputs a signal indicating an abnormality in the current detector when the effective value of the voltage command value is equal to or greater than the voltage command threshold and the effective value of the current detection value is equal to or less than a current detection threshold that is lower than the reference current value.