GaN-based LLC resonant converter with a 2.5 MHz resonant frequency
The DC-DC converter plays a pivotal role in secondary power supplies for aerospace applications.The ongoing development trend for aerospace power supply converters emphasizes compact size,lightweight,and high-power output.To achieve these goals,enhancing the"power-to-weight ratio"and increasing the switching frequency are critical strategies.Notably,the pursuit of higher frequencies is a significant focus for future DC-DC converters.In this paper,GaN(Gallium Nitride)based HEMTs(High Electron Mobility Transistors)is employed as a switching device to investigate the impact of device characteristics on the maximum achievable operating frequency when the LLC resonant converter operates in the soft-switching mode.It is found that reducing the output capacitance of GaN devices leads to higher switching frequencies.However,it is essential to consider the tradeoff between frequency and power losses.To address this problem,we establish an accurate loss model for GaN devices,providing valuable insights for optimizing efficiency.Finally,a 200W 270 V～28 V LLC resonant converter is realized and the detailed analysis is carried out.By utilizing GaN devices as a switching component,a high-frequency converter operating at 2.5 MHz is achieved.The resulting power-to-weight ratio reaches 3.1 kW/kg,with a peak conversion efficiency of 92.8％.Our prototype validates the feasibility of designing higher-frequency LLC converters,and provides a design reference for the future production of a high-frequency converter.
gallium nitrideresonant convertershigh resonant frequency
万方数据
维普
