iTHD Improvement for Interleaved Totem-pole CRM PFC

This paper presents a control scheme to improve interleaved critical conduction mode (CRM) Totem-pole PFC input current distortion (iTHD).The Totem-pole CRM control PFC provides zero voltage soft switching (ZVS) feature. All power switches are turned off around grid voltage crosses zero volt (0V) (GVCZ) area in the conventional Totem-pole CRM control to avoid power switches working at extremely high switching frequency. This high switching frequency working may destroy the power switches. PFC input current is zero around GVCZ area when power switches are turned off in the conventional CRM control. This turned off control scheme will result in current distortion. This paper proposes a method to keep power switches continuously working at high switching frequency mode during the entire sinusoidal period without turning off around GVCZ area. The switching frequency can be limited by the proposed method. This control scheme makes the PFC input current to be controlled within the whole sinusoidal period. Better PFC input current iTHD is gotten. 3.3kW onboard charger (OBC) with GaN devices is built to verify the control scheme. The PFC input current iTHD is mitigated from 2.78% to 1.29% with proposed control scheme.