移相全桥和LLC技术在电推进PPU上的应用对比

Comparison of Phase-shifted Full Bridge and LLC Technology in Electric Propulsion PPU

分别采用移相全桥和全桥LLC设计了离子电推进电源处理单元(PPU)屏栅电源模块。针对恒流启动、打火保护、负载调整率等特性开展了设计和实验验证。得出移相全桥变换器应用在PPU设计显著提高了效率,但整流二极管和变压器绕组的电压应力较高,限制了单模块能够输出的最大电压;全桥LLC变换器消除了输出端滤波电感和箝位电路,降低了绝缘设计的难度和体积重量,劣势在于在输入电压范围变宽时效率下降明显。

The grid power module of power processing unit(PPU)is designed by using phase-shifted full bridge and full bridge LLC respectively.The constant current start-up,ignition protection and load regulation are designed and verified by experiments.It is concluded that the phase-shifting full bridge converter can significantly improve the efficiency of PPU,but the voltage stress of rectifier diode and transformer winding is high,which limits the maximum output voltage of a single module,the full bridge LLC converter eliminates the filter inductance and clamp circuit at the output end,reduces the difficulty and volume weight of the insulation design,but the disadvantage is that the efficiency decreases when the input voltage range is widened obviously.