To suppress distortion in the three-phase output waveform when the output changes.

A single-phase/three-phase matrix converter includes a capacitor which absorbs the pulsation component of single-phase AC power, and a switching circuit which converts the single-phase AC power into three-phase AC power while performing pulsation compensation by using the generating power of the capacitor. From the output power p_out and the detection value of power supply voltage e based on the output voltage command value and output current detection value of three-phase AC power, a power supply current reference command value i_rb^*, a capacitor current reference amplitude (amplitude reference command) I_sb^*and a capacitor voltage command value v_st^*are derived, and then a capacitor current command value i_s^*is obtained by correcting the I_sb^*so that the difference between the v_st^*and the capacitor voltage detection value v_st goes zero. Meanwhile, an input instantaneous power p_in is obtained based on the e, v_st, i_s^*and i_rb^*, and the difference Δp from an output instantaneous power p_out is obtained, and then a power supply current command value i_r^*is created by correcting the i_rb^*so that the Δp goes zero.