Patent ID: 7450401

Claim:
A bidirectional DC/AC inverter, comprising: a first power conversion unit; a second power conversion unit; a third power conversion unit; and a control unit for controlling respective operations of the first through third power conversion units, wherein the first power conversion unit converts an inputted AC power into a DC power, and the second power conversion unit converts the immediately aforementioned DC power into an AC power, and the third power conversion unit converts the immediately aforementioned AC power into a DC power thereby supplying the DC power to a battery at the time of charging said battery, the third power conversion unit converts a DC power obtained from the battery into an AC power, and the second power conversion unit converts the immediately aforementioned AC power into a DC power, and the first power conversion unit converts the immediately aforementioned DC power into an AC power thereby outputting the AC power from the aforementioned bi-directional DC/AC inverter, and the control unit makes a switching element, a capacitor, which constitute the first power conversion unit, and a coil, which constitutes a filter which is connected to the first power conversion unit, operate as an active filter at least during a period of time in which a terminal voltage of the battery is equal to or greater than a predetermined voltage, thereby making an input voltage to the second power conversion unit adjustable at the time of charging the battery.