Matsushita Electric Works, Ltd.

Shinji Hizuma

Toshiaki Nakamura

Yutaka Iwahori

Tsutomu Shiomi

Hiroichi Shinbori

Takeshi Kamoi

Naoki Komatsu

Power source device including a plurality of switching circuit for power

A power device includes at least two power conversion circuits respectively having at least one of switching elements, at least one of which switching elements in these conversion circuits being used in common as an element constituting the at least two different power conversion circuits, a control device providing at least a period in which at least one of currents flowing from at least one of the different power conversion circuits to the commonly used switching element has a polarity inverse to at least the other one of the currents flowing from at least the other one of the power conversion circuits, so as to cancel each other, and a unit for detecting the state of the respective conversion circuits. The operation of the switching elements is thereby made modifiable in accordance with a lowering in the resistance of a load of the device, and the withstand voltage of the elements can be prevented effectively from rising even upon any fluctuation in the load.

Power device with commonly used switching elements

A power source device is so arranged that one of switching elements forming a plurality of power conversion switching circuits which is used in common during each switching cycle is made to have a switching period in which mainly a current is taken up from a power source of first one of the switching circuits, the switching period being varied in a zone in which an input voltage is higher than a predetermined voltage in a cycle of input voltage waveform. Any distortion of input current waveform occurring around lower voltage period of commercial AC source is thereby reduced, in the power source device wherein the power conversion switching circuits employ commonly the switching elements.

Power source device

Growing community of inventors

Ibaraki, Japan

Shinji Hizuma