A New Interleaved Isolated Boost Converter for High Power Applications

Isolated boost converter is desirable in the low-to-high dc/dc application where isolation is required or a large step up is in a need. The challenge of designing such a converter for high power applications is how to handle the high current at the input and high voltage at the output. An effective way is to parallel the inputs and series the outputs of the isolated boost converters. Based on this concept, a new interleaved and isolated boost converter is proposed in this paper that has two inductors in parallel at the input to share the current and two capacitors in series at the output to share the voltage. The current stresses and voltage stresses of the converter are both alleviated. The two boost converter cells realize demagnetizing by helping each other, which simplifies the transformer structures. With interleaved operation, the current ripple is smaller; therefore, it is possible to use smaller capacitors at the input and output of the converter. All these features make the new interleaved isolated boost converter desirable for high power low-to-high dc/dc applications. The proposed interleaved isolated boost converter is presented based on the basic isolated boost converter, but the interleaved structure is applicable to other isolated boost converters including the full-bridge converter, the push-pull converter, and the L-type half-bridge converter. The theoretical analysis is verified by a 200W prototype.