Dynamic deadtime control of a GaN-HEMT-based power factor correction converter for efficiency improvement

Gallium nitride (GaN) material emerged as the third-generation semiconductor material due to its superiorities of high critical breakdown electric field, high saturation electron velocity, high electron mobility, and high thermal conductivity. These advantages enable GaN to be suitable for high-density applications such as power factor correction (PFC) circuit. As a typical AC/DC converter, PFC is extensively applied in electric vehicle charging, electronic device power supply etc. However, most GaN devices on the market are enhanced-mode planar high electron mobility transistors (HEMTs). Their high third-quadrant forward voltage leads to large freewheeling conduction loss which significantly increases the power loss of the PFC. To improve the power efficiency, this paper comprehensively analyses the power loss mechanism of a totem-pole PFC converter during the dead time. Based on the analytical results, a dynamic deadtime method for deadtime loss reduction is proposed. The simulation is conducted to validate the analysis and the functionality of the proposed method.