A Cost-Effective Controlled-Type ZVS Technique for GaN-Based Totem-Pole PFC rectifier

In this paper, a controlled-type ZVS technique for totem-pole PFC rectifier with limited maximum switching frequency operating in boundary conduction mode and discontinuous conduction mode is studied. Conventional ZVS methods for totem-pole PFC rectifier may require detecting zero crossing point of inductor current or implanting auxiliary circuits. To avoid this, a cost-effective ZVS technique based on software calculation without hardware circuits is studied. SR conduction time extension is applied to compensate the non-ZVS region. By limiting the maximum switching frequency near zero crossing point of AC gird voltage or in light-load mode, the totem-pole PFC switches between BCM and DCM. Therefore, frequency-related loss is reduced especially in light-load mode. Simulation results verify the feasibility of the studied technique. A 400W prototype has been built to verify the effectiveness and advantages of studied method.