Hitachi Information & Telecommunication Engineering, Ltd.

Nobuyuki Aihara

Akihiko Kanouda

Takae Shimada

Fumikazu Takahashi

Yoshihide Takahashi

A power supply device of the invention includes a first switching leg including first and second switching elements between DC terminals; a second switching leg including third and fourth switching elements between the DC terminals; a first capacitor leg including first and second capacitors between the DC terminals; a second capacitor leg including third and fourth capacitors between AC terminals; a first inductor between a connection of the first and second switching elements and one of the AC terminals; a second inductor between a connection of the third and fourth switching elements and another of the AC terminals; a controller; an AC power supply connected to the AC terminals and the connection of the third and fourth capacitors; and a DC power supply between the DC terminals, wherein the controller charges the first and second capacitors to a voltage higher than a voltage crest of the AC power supply.

Power supply device operating switching elements of first and second switching legs to charge first and second capacitors to a voltage higher than a voltage crest value of an AC power supply and method of operating the power supply device

A highly efficient power supply unit compatible with a single-phase three-wire system and an operating method of such a power supply unit are provided. The power supply unit includes first and second switching legs connected in parallel to a first capacitor leg with a DC power supply connected thereto. One end of the second capacitor leg is connected to the middle point of the first switching leg through a first inductor, and the other end is connected to the middle point of the second switching leg through a second inductor. The two ends of the second capacitor leg and the middle point of the second capacitor leg are defined as AC terminals. A switch is provided between middle points of first and second capacitor legs. A control part sets the switch to OFF when power is input/output only between one end of the second capacitor leg and the other end.

Growing community of inventors

Yokohama, Japan

Nobuyuki Aihara