A Novel Hybrid Two-Stage AC-DC Converter with Soft-Switched CCM PFC Stage for EVs Charging Applications

Abstract:
Totem-pole rectifiers are widely adopted in electric vehicles (EVs) on-board chargers. Conventional totem-pole rectifiers suffer from either high conduction losses in triangular current mode (TCM), or high switching losses in continuous conduction mode (CCM). To tackle this challenge, this paper presents a novel hybrid two-stage solution where the totem-pole rectifier can achieve CCM and soft switching simultaneously. Our new solution is achieved by smartly introducing current from the back-end LLC stage into the front-end totem-pole PFC stage, creating a Zero Voltage Switching (ZVS) condition for the PFC stage despite operating in the CCM. A scaled-down 100-W EVs charging prototype is developed to validate the proposed concept.