A Hybrid Resonant Converter Utilizing a Bidirectional GaN AC Switch for High-Efficiency PV Applications

This paper introduces a novel isolated hybrid resonant converter with smooth transition between multiple operating modes. With the simple addition of a bidirectional ac switch, the highly efficient series resonant converter operating in the discontinuous conduction mode is combined with a phase-shifted full-bridge buck converter and a pulsewidth-modulated boost converter in order to provide high power conversion efficiency over a wide input-voltage operating range utilizing a simple topology and simple control techniques. First, the topology is introduced, and the converter's operating modes are discussed. Next, closed-loop input-voltage controllers are designed for the different operating modes, and a smooth transition technique is introduced using a two-carrier modulation scheme. Experimental results are provided to verify the proposed system using a 300-W prototype that achieved a 97.5% California Energy Commission weighted efficiency with a 30-V input including all auxiliary and control losses.