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 (DCM) is combined with a phase-shifted full-bridge buck converter and a pulse width modulated (PWM) 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 (CEC) weighted efficiency with a 30-V input including all auxiliary and control losses.