Design and Implementation of A 5kW 99.2% Efficient High-Density GaN-based Totem Pole Interleaved Bridgeless Bidirectional PFC

This paper presents the design of a high-density GaN-based totem pole interleaved bridgeless bidirectional PFC. The bridgeless design approach and zero reverse-recovery loss characteristic of GaN allows efficient operation better than that of comparable Si-based designs. Forced air-cooling in combination with an efficient thermal design contribute to a power density which exceeds 87W/inch3 while maintaining device temperatures well below thermal limits. CCM operation of the converter is analyzed in detail and is accompanied by a breakdown of losses. A steady-state thermal model is utilized to predict GaN device junction temperature and provide high overcurrent capability. Experimental results verified a peak efficiency of 99.2% during DC-DC operation at 2.5kW and a full-load efficiency of 99.1% at 5.4kW under DC-DC operation.