Comparison of Single-Phase GaN HEMT-based PFC Topologies for Onboard EV Chargers

A standard onboard charger typically consists of two stages, wherein the power factor correction (PFC) acts as the initial stage. This study explores various bridgeless PFC topologies - bridgeless totem-pole PFC (BTPFC), interleaved BTPFC, and H-bridge with sine-triangle PWM (SPWM) - suitable for a 3kW power rating. 650 V gallium nitride high electron mobility transistor (GaN HEMT) devices, known for their superior switching characteristics and thermal performance, are used in these PFC topologies. This research provides a comprehensive analysis of the distinct losses encountered in each PFC topology, including conduction losses, switching losses, dead time losses, and partial hard turn-on losses. Taking into account a bridge loss limit of 1 - 1.5% of total power and a thermal limit of 70% of the maximum junction temperature, the paper presents a detailed selection of switching frequency for the PFC topologies. Additionally, it provides a comparison of boost inductors and filter capacitors based on the chosen switching frequency.