ZVS HF resonant converter with bidirectional switches

The simulation of the controlled HF AC link resonant power converter with bidirectional switches is shown in the paper. The main-side converter controller fulfils the requirements of sinusoidal input currents, zero voltage switching and nearly constant resonant voltage amplitude. At the load side, a simple on-off current controller is implemented. The zero voltage switching technique (ZVS) reduces the switching losses and introduces a modulation strategy called pulse density modulation (PDM). The simulation program PADSIM with user-programmable blocks was used to analyze the complete converter. Simulation results give valuable insights into necessary control actions, about resonant tank design and about robust bidirectional switch necessity. Resutls of laboratory experiments with a half-bridge converter with two bidirectional switches are shown finally. The switch consists of two IGBTs with a single driver circuit. With proper driver voltage, switching actions without snubber elements are allowed