Fully Soft Switching Single-Stage Isolated Three-Phase AC to DC Series Resonant Converter

The single-stage isolated three-phase ac to dc series resonant converter is presented in this work as a promising solution for light electric vehicle charging and grid coupling of renewable energy. This converter features guaranteed soft switching throughout all switching events, potential of unity power factor, high power density, high efficiency and low cost. A control technique, along with a switching scheme based on a dynamic circuit model, is introduced in this research. Additionally, switching events near zero crossings of the resonant current are analyzed in detail to sustain fully zero voltage switching. The converter's operation is initially verified through simulations. Subsequently, experiments are carried out using a setup with a 1 kW power rating at 400 Vac three-phase input to validate the practical implementation. The transient behavior and efficiency of the converter are experimentally investigated. Some challenges during implementation such as measurement time constraints are stated and possible solutions to these challenges are discussed and realized.