Power Loss Modeling of GaN Bidirectional Switches in a Single-Branch Harmonically Partitioned Power Converter

The recently proposed Harmonically Partitioned Power Converter (HPPC) enables miniaturization and performance enhancement of single-phase ac/dc converters by achieving single-stage conversion, automatic unity power factor, complete power pulsation decoupling, and energy transfer through a high-frequency tank instead of a dc link. This work presents an analytical power loss model for the bidirectional switches (BDSs) used in a Class A-I single-branch HPPC, explicitly accounting for the asynchronous relationship between their conduction currents and blocking voltages. Dead time dynamics in the source-connected GaN BDSs under dual-gate synchronous control (DGSC) are modeled, and physical explanation of parasitic charging phenomena in both partial zero-voltage-switching (ZVS) and hard-switching scenarios is described. The loss model is validated against experimental results, estimating total losses within 10.4% of measured values and parasitic charging voltages of 4.0% and 11.0% discrepancy for partial ZVS transitions. The general hard-switched overcharging phenomenon is accurately predicted by the model.