Design of a 1.5kW High-Efficiency LLC Resonant Converter Based on GaN

A design solution for an LLC resonant converter is proposed to meet the requirements of high efficiency, high power density, and low voltage high current output. The high-voltage side of the converter utilizes GaN devices with fast switching speed and low losses to achieve high efficiency and high power density. The transformer adopts a series connection on the high-voltage side and a parallel connection on the low-voltage side to meet the demand for high current output, while using copper foil windings to reduce losses. To achieve the specifications of 370–390 V input, 28 V output, 1.5 kW power, and 650 kHz resonant frequency, an LLC resonant converter based on GaN devices was designed, and a prototype was built to verify the feasibility of the design. Experimental results showed that the proposed LLC design achieved 98% efficiency and a power density of 524 W/in3 at 1.5 kW, 28 V/53.5 A output.