A single-stage zero-voltage zero-current-switched full-bridge DC power supply with extended load power range

A single-stage power-factor-corrected pulsewidth modulation converter with extended load power range is presented, The topology is based on a zero-voltage zero-current-switched full-bridge (ZVZCS-FB) inverter. Steady-state analysis of the topology shows that by operating the LC load filter in discontinuous mode, the de-link voltage remains bounded and independent of the load level. Therefore, the load power range can be further expanded, including the no-load operating condition. The analysis also shows that the extension of the load power range is achieved without any penalty in: 1) the input power factor (due to the input current waveshaping feature); 2) the converter efficiency (due to ZVZCS and the single-stage features); and 3) the load voltage quality (due to the high bandwidth of the phase control loop). Simulated and experimental results are included to show the feasibility of the proposed scheme.