Parasitic ringing and design issues of high power interleaved boost converters

High power boost converter has become the essential part of the distributed power system that enables energy to be fully utilized in fuel cell powered electric vehicles and stationary power systems. This paper presents analysis and design of a high-power multi-leg interleaved boost converter. A 20 kW converter was designed with coupled inductors to allow core-loss reduction and designed with high frequency switching to minimize the component size and eliminate the switching losses under discontinuous conducting mode (DCM) operation. Although the design challenges were mainly in optimization of device and component selection for cost and size reduction. It was found through circuit analysis, simulation and experiment that the boost inductor interacted with the device parasitic capacitor and created unnecessary oscillating current whenever it reached zero current. Two high-power devices were used in both simulation and experiment to verify the analysis and design for a wide load range.