LLC谐振半桥变换器的设计

The Design of LLC Resonant Half Bridge Power Converter

LLC谐振半桥变换器可以在全电压范围内、全负载条件下使得初级端 MOSFET实现ZVS（零电压开关），次级整流二极管实现ZCS（零电流开关），减少了开关损耗，大大提高了效率。而且在输入电压和负载范围变化比较大的情况下，其开关频率变化较小，有利于主参数的设计。这种变换器通常应用在高频功率变换领域。文中首先使用 FHA（基波近似原理）进行 LLC谐振半桥变换器的建模，然后分析了如何对变换器中的电气参数进行选择，最后设计了一个工作在70~150 kHz频率下300 W的 LLC谐振变换器。

LLC resonant half bridge power converter can regulate output over wide line and load variation with a rela-tively small variation of switch frequency,while maintaining excellent efficiency.It can achieve zero voltage switching （ZVS）over the entire operating range.It usually used in high power converter region.This paper firstly use first harmonic approximation（FHA）to develop the input-to-output voltage-transfer function.Then it analyzed the selection of electric pa-rameter.Finally,we designed a 300 W LLC converter working at 70~150 kHz.