Adaptive ZVS Control and ZCD Delay Compensation for a Single‐Phase CRM Totem‐Pole PFC Converter

ABSTRACT This paper presents an adaptive zero‐voltage‐switching (ZVS) control and zero‐current‐detection (ZCD) delay compensation strategy for a single‐phase critical‐conduction‐mode (CRM) totem‐pole power‐factor‐correction (PFC) converter. Conventional CRM and quasi‐square‐wave (QSW) control schemes suffer from three inherent limitations: ZVS failure in the high‐input‐voltage region, excessive switching‐frequency rise under light‐load conditions, and input‐current distortion caused by the fixed ZCD propagation delay. To address these issues, a state‐plane‐based model is first established to derive the ZVS condition and its failure boundary. Based on this model, an online timing scheme is developed that incorporates the minimum ZVS time‐margin requirement and the maximum switching‐frequency limit, and adaptive dynamic dead times are introduced to accommodate resonant transitions under varying operating conditions. In addition, a ZCD delay compensation method combining zero‐crossing blocking and full‐line‐cycle feedforward correction is proposed to suppress reverse current and improve input‐current waveform quality. Simulation and experimental results on a 1.6‐kW GaN‐based prototype demonstrate that the proposed method achieves reliable ZVS over the investigated operating range, effectively limits the switching frequency under light‐load conditions, and mitigates the input‐current distortion caused by the ZCD delay.