Optimal Design of DCM LCC Resonant Converter With Inductive Filter Based on Mode Boundary Map

LCC resonant converter with inductive filter operating in discontinuous current mode (DCM) can achieve zero-current switching (ZCS) for both the power switches and rectifier diodes. Therefore, it is suitable for high-power, low-voltage, high-current power supplies. The DCM LCC resonant converter with inductive filter might operate in different operating modes when input voltage or load changes, which challenges the design. This paper derives a mode boundary map, from which the operating mode of the converter can be easily determined. Based on the mode boundary map, a generalized optimal design procedure is proposed and a set of optimal and normalized converter parameters is determined, which can be easily converted into real parameters according to the converter specification. Three 5 kW prototypes with different converter parameters are fabricated and tested in the lab, and the experimental results show that with the set of optimal parameters, the converter can achieve the highest efficiency over the entire input voltage and load range.