A parallel front-end LCL resonant push-pull converter with a coupled inductor for automotive applications

A parallel technique with a coupled inductor is proposed for an LCL resonant push-pull converter. The coupled inductor is inserted in the front of the common resonant capacitor of two parallel push-pull converters, sharing the current of the two converters. The equivalent circuit and state equation of the proposed converter is described, and then the effects of the mismatch of the equivalent resistor and leakage inductor on sharing current is derived. The controller of the cascaded full-bridge inverter is presented. Experimental results of a 2kW inverter showed that the current difference of the two parallel units is less than 2%.