Patent ID: 8786314
Filing Date: 2014-07-22
Classification: H02J,H02M

Abstract:
1. A contactless power transfer system, comprising: a coil configured to supply or receive power contactlessly via magnetic coupling; a bridge circuit having two direct current (DC) terminals and two alternating current (AC) terminals, the two AC terminals being respectively connected to two ends of the coil, the bridge circuit including two serially-connected circuits each having an upper arm and a lower arm, each of the upper and lower arms having a semiconductor switch and a diode in reverse parallel connection; a smoothing capacitor connected between the two DC terminals of the bridge circuit, a load being connectable to either end of the smoothing capacitor; a capacitor connected in parallel to the semiconductor switch of one of the upper and lower arms of the bridge circuit; and a control device configured to generate drive signals to control the semiconductor switches of the bridge circuit, based on a DC output voltage of the bridge circuit and a current flowing through the coil, wherein the drive signals include signals that put all of the semiconductor switches of the bridge circuit into an off condition during a period for which a power transfer to the coil is stopped, and that cause each of the semiconductor switches to carry out a switching action after a zero-crossing of the current of the coil is detected when power transfer to the coil is started.