Novel Continuous Transition of CCM and DCM Switching Control Method for Efficiency Improvement of PFC

A novel continuous transition of CCM and DCM switching control method for PFC is proposed in this paper. Continuous transition between CCM and DCM can be automatically achieved without requiring any additional zero crossing point detection circuit and thereby reducing the cost and losses. The proposed switching control method calculates the “quasi-SR” duty based upon the input and output voltages. As the “quasi-SR” duty is smaller than the complementary duty, the calculated “quasi-SR” duty is used for the synchronous rectification (SR) power device switching. Otherwise, conventional complementary duty is used. A 3 kW Totem-pole PFC is set-up for test. The experimental results show the efficiency can be significantly improved as input AC voltage = 110, 230 and 264 Vrms, and the 99.28% of peak efficiency is achieved.