A new soft-switched contactless battery charger with robust local controllers

A new soft-switched contactless battery charger with an improved local controller is described. The controller consists of a primary-current feedback control circuit in the inverter side and an output-voltage feedback control circuit in the rectifier side. By controlling the primary current of the inverter side, the maximum transferable power through the inductive coupling is automatically kept constant over the entire input voltage and load ranges. As a result, excessive circulating energy in the charger is minimized. Moreover, by incorporating the proposed controller, zero-voltage switching (ZVS) of all power switches is achieved. Finally, the proposed controller provides a tight regulation of the output voltage over the entire load and input voltage ranges without any feedback connection between the rectifier side and the inverter side.