Component Stress Minimization of Resonant DC/DC Converter Using Fractional Power Processing for Battery Charging

A fractional power processing architecture is presented in this paper enabling a solution to the high voltage and current stress issues across the resonant converters. The proposed configuration allows only a differential voltage and differential current to appear across the converter terminal thereby, reducing the voltage and current through the converter components. The converter is connected in an input parallel output series (IPOS) configuration with the battery load and available DC source, respectively. Thus, the proposed configuration of the converter reduces the losses and thereby improves the efficiency of the overall charger. Further, a reduction in size of heat sink and optimization in component rating makes it a cost-effective and compact solution. The proposed architecture is implemented using a DAB-derived current fed parallel resonant converter that maintains soft-switching for the entire range of operation. The design criterion of the proposed charger is presented. The constant current -constant voltage behavior of the proposed converter is verified through simulation. The suitability of the proposed solution for battery charging is verified using a 700 W lab developed prototype.