Design and Performance Optimization of a Low-Power Half-Bridge LLC Resonant Converter Using GaN FETs

This paper presents the design, implementation, and experimental validation of a cost-effective 500W half-bridge LLC resonant DC-DC converter optimized for high-efficiency, low-power applications. The converter utilizes Gallium Nitride (GaN) FETs, achieving a peak efficiency of around 90% to meet the increasing demand for compact and reliable power conversion in the renewable energy, industrial automation, and telecommunication sectors. It operates with a nominal input voltage of 72V (in a range of 63 to 75V) and delivers a 14.5V/40A output. The resonant tank design methodology ensures exclusive inductive region operation, enabling zero voltage switching (ZVS) under all load conditions to minimize switching losses, electromagnetic interference (EMI), and device stress. Experimental results demonstrate a 1–10% efficiency improvement using GaN FETs over traditional MOSFETs, particularly at higher power levels. The design incorporates an adaptive protection framework that includes configurable over-voltage, under-voltage, and over-current precautions to ensure resilience under transient and fault conditions. We confirm stable operation at a 100kHz switching frequency through comprehensive load-varying tests, maintaining high efficiency across different load conditions.

Recommended citation: Isuru Munasinghe, Ashen Rodrigo, "Design and Performance Optimization of a Low-Power Half-Bridge LLC Resonant Converter Using GaN FETs," 15th International Conference on Electrical Engineering (ICEENG), Cairo, Egypt, 2025, pp. 1-6, http://dx.doi.org/10.1109/ICEENG64546.2025.11031338
Download Paper