Analysis of Power Conversion Efficiency Characteristics of Large Capacity Bridgeless PFC Circuits using GaN Switches under Varying Switching Frequencies

In this paper, a GaN switch is applied to a 2kW class large capacity bridgeless power factor correction (PFC) circuit to report the comparative test results according to switching frequency variation from 50kHz to 100kHz.Especially the efficiency was 98.36% at a switching frequency of 60kHz and 98.2% at 100kHz while the efficiency was reduced to 98.29% at 50kHz.This was estimated because the core loss of the inductor and the switching loss of the GaN were proportional to the switching frequency.When the frequency was below a certain value, a decrease in efficiency was observed due to an increase in current ripple and power loss by the insufficient inductance in the test circuit.Therefore, in the bridgeless PFC with GaN FET, once the switching frequency and the optimum inductance value were determined, the power conversion efficiency was not improved even when the switching frequency was increased.