Patent ID: 7262982

Claim:
A power conversion apparatus comprising at least three legs connected in parallel between a direct-current positive terminal and a direct-current negative terminal, a first semiconductor power device and a second semiconductor power device connected in series to each of the legs, and an alternating-current terminal, each leg including an upper arm and a lower arm, the power conversion apparatus being allowed to convert an alternating current to a direct current, or the direct current to the alternating current, and to supply the converted current to a load connected between the direct-current positive terminal and the direct-current negative terminal, or connected to the alternating-current terminal, wherein at least one unit communication-assisting means is connected in series between a series-connection point of the first and second semiconductor power devices of each leg and the alternating-current terminal, whereby a plurality of unit communication-assisting means are connected to the legs, the plurality of unit communication-assisting means each including a chargeable/dischargeable charge element, and a first self-commutated device and a second self-commutated device which are connected in a back-to-back connection manner with respect to the charge element.