Optimization of CRM Totem Pole PFC Based on Inductor Current Zero-Crossing Prediction Strategy

The totem-pole bridgeless PFC circuit based on GaN devices is currently a research hotspot. To achieve full-range ZVS (Zero Voltage Switching), it is necessary to select a reasonable ZCD (Zero Current Detection) sampling scheme and dead time for the inductor current in CRM (Critical Conduction Mode). Addressing the issues of large computational burden and poor reliability in current inductor current zero-crossing prediction strategies, this paper proposes optimizing the turn-off time of the freewheeling diode and the adaptive dead time to improve the reliability of inductor current zero-crossing prediction and the realization of full-range ZVS. Finally, leveraging the powerful computational capability of a high-performance DSP, the proposed method was validated through reasonable software design and the establishment of an experimental platform.