The type of North American domestic distribution voltage is two phase three wire,which consist oftwo live wires having phase difference 180°and one neutral wire. Gird connected inverter applied to this voltage is alsoconfronted with unbalance load. And then,three level structure with DC link midpoint connected to neutral point isadopted to restrain common mode voltage of non insolated grid connected inverter. The method of the outer DC voltageloop and the inner inverter current loop was adopted,which adding...