Bidirectional soft switching arm topology for a nonresonant HF link converter

For the purpose of making operating frequency higher to reduce the dimensions and weight of a power converter and its EMI (electromagnetic interference) problems, so-called soft-switching has become a far more important technique today. There exist two approaches toward ideal soft-switching circuit topologies. One is based on nonresonant converter techniques using snubbers, and the other is based on resonant converter techniques. The author previously proposed a novel totally soft-switched high frequency converter from the nonresonant approach. However, there remained a problem of undesirable effect due to parasitic diodes in each bidirectional switching are on its soft-switching characteristics. This effect is remarkable especially in the case of using MOSFETs. This paper presents an improved arm topology to prevent such undesirable effect, and confirms total soft-switching operation in an experimental manner.