Merstech, Inc.

Hideo Sumitani

Takanori Isobe

Ryuichi Shimada

Taku Takaku

The present invention relates to an alternating-current power supply device which can improve a power factor of an alternating-current load, realizes low cost and miniaturization, and recovers magnetic energy. The alternating-current power supply device includes a bridge circuit composed of four reverse conducting semiconductor switches, a capacitor that is connected between direct-current terminals of the bridge circuit and absorbs the magnetic energy at the time of cutting off the current, an alternating-current voltage source that is connected to the induction load in series and is inserted between alternating-current terminals of the bridge circuit, and a control circuit that gives a control signal to gates of the respective reverse conducting semiconductor switches and controls on/off states of the respective reverse conducting semiconductor switches. The control circuit simultaneously controls the on/off operation of the paired reverse conducting semiconductor switches positioned on a diagonal line of the four reverse conducting semiconductor switches composing the bridge circuit, makes a control so that when one pair of the two pairs is ON, the other pair is OFF, and switches the control signal in synchronization with a voltage of the alternating-current voltage source.

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Tokyo, Japan

Hideo Sumitani