It is determined that a periodic zero current stagnation state is reached to correct a voltage command of a smoothing capacitor downward by a predetermined voltage when a state where a current (reactor current) flowing through a coil in a dead time when switching elements are both off immediately after the switching element (upper arm) is turned off from on stagnates at a value of 0 occurs at switching periods of the switching elements. This can prevent a voltage of the smoothing capacitor from becoming unexpectedly higher than the voltage command in the current stagnation state, prevent the smoothing capacitor from being damaged by an overvoltage and prevent excessive torque from being output from motors.