基于GaN HEMT的MHz LLC直流变压器的设计

Design of GaN-based MHz LLC DC Transformer

为实现母线变换器的高效率和高功率密度,应用GaN HEMT将LLC-DCX的开关频率提高到1 MHz,在提高了变换器的功率密度的同时,实现了较高的转换效率。在介绍LLC谐振变换器的工作原理和特性的基础上,优化设计了LLC谐振变换器的谐振参数和平面变压器结构,最后研制出一台1 kW、1 MHz,额定270 V(230~400 V)输入,额定28 V输出的LLC-DCX实验样机,其峰值效率为97.57%,功率密度高达18.89 W/cm^(3)。实验结果验证了该方案的合理性与可行性。

To improve the efficiency and power density of the bus converter,the GaN HEMT is used to increase the switching frequency of LLC-DCX to 1MHz,which greatly improves the power density while maintaining the higher conversion efficiency.On the basis of introducing the operation principle and characteristics of LLC resonant converter,the resonant parameters and planar transformer structure of LLC resonant converter are optimized.Finally,a 1 kW,1 MHz,LLC-DCX experimental prototype with 270 V(230~400 V)input voltage and 28 V output voltage was built and tested.The measured data show the converter achieves the peak efficiency of 97.57%and the power density of 18.89 W/cm 3.The experimental results show the validity and feasibility of the proposed solution.