Patent ID: 8611120

Claim:
A power conversion apparatus comprising: a three-level inverter including a bridge circuit including a first semiconductor switching device and a second semiconductor switching device connected in series, the bridge circuit being connected to a positive terminal and a negative terminal of a DC power supply, a switch circuit having a bidirectional characteristic and connected to an AC output terminal of the bridge circuit which is a connection point between the first semiconductor switching device and the second semiconductor switching device, and to an intermediate potential point of the DC power supply, a first smoothing capacitor connected to the intermediate potential point of the DC power supply and connected to the positive terminal of the DC power supply, and a second smoothing capacitor connected to the intermediate potential point of the DC power supply and connected to the negative terminal of the DC power supply; a single-phase inverter including a plurality of semiconductor switching devices and a capacitor, and connected in series to the AC output terminal of the bridge circuit, wherein a voltage of the capacitor of the single-phase inverter is smaller than each voltage of the smoothing capacitors of the three-level inverter, a drive frequency of the semiconductor switching devices of the single-phase inverter is higher than a drive frequency of the semiconductor switching devices of the three-level inverter, and a sum of an output voltage of the three-level inverter and an output voltage of the single-phase inverter is supplied to a load.