Patent ID: 9608539
Date: 2017-03-28
CPC Classifications: H01F,H02J,H02M,Y02B

Claim:
1. A power supply device comprising: a coil configured to exchange power by an external magnetic coupling; a bridge circuit in which one end of the coil is connected to one alternate current (AC) terminal through a resonance capacitor and another end of the coil is connected to another AC terminal; and a smoothing capacitor configured to be connected between direct current (DC) terminals of the bridge circuit, a load being connected at both ends of the smoothing capacitor, and the bridge circuit being configured such that a plurality of switching arm series circuits in which two inverse parallel connection circuits of a semiconductor switch and a diode are connected in series are connected in parallel, wherein the power supply device comprises: a current detection unit configured to detect a current which flows through the coil as an input current; a voltage detection unit configured to detect a voltage between the DC terminals as an output voltage; and a control unit configured to switch the semiconductor switch at a constant cycle such that a voltage between the AC terminals of the bridge circuit becomes a zero voltage only during a prescribed time period before and after two zero crossing points in one cycle of the input current and such that the voltage becomes a positive voltage or a negative voltage in which the output voltage is a peak value during a time period other than the prescribed time periods.