Abstract: A power converter comprising: a three phase bridge circuit, each phase of which is composed of series-connected positive and negative arms, each of which arms includes series-connected GTOs; free-wheel diodes coupled in reverse parallel with every GTO; phase snubber circuits provided for every phase, each of which includes series-connected diodes coupled across the series-connected arms through a first capacitor, a junction of the diodes being coupled to a junction of the series-connected arms through a second capacitor and a junction of the first capacitor and the series-connected diodes being coupled to a negative dc terminal through a resistor; and individual snubber circuits provided in the respective GTOs, each of which includes a series connection of a diode and a third capacitor as well as a resistor connected in parallel with the diode; in which the first capacitor has capacitance much larger than the second capacitor, which in turn has capacitance much larger than the third capacitor.