Adaptive zero-voltage-switching control and hybrid current control for high efficiency GaN-based MHz Totem-pole PFC rectifier

This paper presents an adaptive Zero-Voltage-Switching control (ZVS) method and a hybrid current control strategy for the GaN-based MHz Totem-pole PFC rectifier. This novel ZVS control achieves the minimum ZVS time margin and maximum switching frequency clamping by adaptively controlling the synchronous rectifier (SR) turn off current. This adaptive SR turn off current control is a unified control strategy based on a proposed unified analytical converter model. The analytical model and the control strategy are applicable for full-range of input voltage and full-range of load for ZVS Totem-pole PFC. In addition, a dual-loop current control strategy is also proposed in this paper. This dual-loop current controller uses the outer average current control loop to directly regulates the inductor average current. The inner current control loop combines the peak current controller and the time based SR turn off current controller. The proposed SR turn off current control for ZVS is adaptively controlled by this time based controller. To verify the proposed ZVS control method and the hybrid current controller, a 1.5kW GaN-based MHz Totem-pole PFC prototype is demonstrated with full-range ZVS, 99% peak efficiency and high quality AC current.