Patent ID: 9166501
Filing Date: 2015-10-20
Classification: H02M

Abstract:
1. A power supply unit comprising: a first switching leg in which a first switching element and a second switching element are connected in series; a second switching leg in which a third switching element and a fourth switching element are connected in series, while also being connected to the first switching leg in parallel; a first capacitor leg in which a first capacitor and a second capacitor are connected in series, while also being connected to the first switching leg in parallel; a second capacitor leg in which a third capacitor and a fourth capacitor are connected in series, with the series connection point of the third and fourth capacitors being connected to the series connection point of the first and second capacitors; a first inductor connected between the series connection point of the first and second switching elements, and one end of the second capacitor leg; a second inductor connected between the series connection point of the third and fourth switching elements, and the other end of the second capacitor leg; and a control part for controlling the on/off state of the first to fourth switching elements, wherein a DC power supply is connected in parallel to the first capacitor and/or the second capacitor and/or the first capacitor leg, wherein one end of the second capacitor leg is defined as a first AC terminal, the other end of the second capacitor leg is defined as a second AC terminal, and the series connection point of the third and fourth capacitors is defined as a third AC terminal, wherein a switch is inserted between the series connection point of the first and second capacitors, and the series connection point between the third and fourth capacitors, wherein the control part sets the switch to the OFF state when power is output only between the first and second AC terminals of the second capacitor leg.