An inverter system includes an input inverter including a positive and a negative DC input terminals and first and second AC output terminals; and a bidirectional inverter device, including a first bidirectional subinverter and a second bidirectional subinverter. The first and second bidirectional subinverters have DC terminals that are interconnected in parallel with a DC power storage device. The first bidirectional subinverter have first and second AC terminals. The first AC terminal is connected to the first AC output terminal of the input inverter. The second bidirectional subinverter have first and second AC terminals. The first AC terminal is connected to the second AC output terminal of the input inverter. The second AC terminal of the first bidirectional subinverter and the second AC terminal of the second bidirectional subinverter are interconnected.