基于SiC MOSFET的高压输入LLC变换器研究

Research on SiC Based High Input Voltage LLC Resonant Converter

针对高输入电压场合，设计了基于SiCMOSFET的共初级开关管的多变压器输入串联输出并联LLC变换器。通过采用SiC器件提高了变换器开关频率，减小了DC／DC变换器体积。对电路工作原理和均流特性进行了分析，从效率和控制复杂度的角度合理选择电路参数，降低开关损耗，提高变换器效率。最后，制作了一台输入电压为800—1000V，输出为25V／2kW的样机，验证了LLC变换器设计的合理性。

For high voltage input application, an LLC resonant converter with SiC MOSFET is built, whose transformer primary sides are connected in series and secondary sides are connected in parallel.SiC MOSFET is used to improve the switching frequency, reduce the size of converter.The working principle and current sharing characteristics of the circuit are discussed.The advantage and disadvantage of each DC converter are analyzed in terms of efficiency, and control difficulty.This circuit reduces switching losses and improves the efficiency of the converter.Experimental results are presented by a prototype with 800-1 000 V input and 25 V/2 kW load.