Optimal design of a low cost 20kW 99.1% efficiency active ZCS isolated dc-dc converter

The paper presents the optimal design of an innovative very high efficiency isolated dc-dc power converter topology. In terms of efficiency and ease to control, it over-performs resonant dc-dc converters from the literature. High efficiency and low cost are obtained by operating low cost IGBT without switching losses with a power factor close to optimal. It is particularly well suited to be employed as module to make low and medium voltage isolated ac/dc converters or fast DC chargers. A variant of the topology allows bidirectional power flow, which enables the efficient and cost effective integration of renewable energies and energy storage into the medium voltage grid. Used as a solid state transformer, it allows higher efficiency than the classical ac distribution transformer and the authors consider it as an enabler for hybrid ac-dc and dc grids.