LLC谐振变换器临界励磁电感的精确设计方法

Precise Design Method of Critical Magnetizing Inductance for LLC Resonant Converter

以LLC谐振变换器为研究对象设计变换器时,在选定死区时间和开关管后,存在临界励磁电感,使变换器恰好在死区时间内完成对开关管寄生结电容的充放电,实现开关管零电压开通(ZVS)。在精确计算出死区时间内电荷供给量的基础上,根据电荷守恒原则推导得到更精确的临界励磁电感设计公式。最后,搭建实验样机,分别基于传统方法和改进方法进行谐振腔设计,结果表明,改进方法能更准确有效地实现开关管的ZVS。

LLC resonant converter is studied, when designing converter, there exists critical magnetizing inductance under given dead time switching device ,which makes the converter exactly reach electric charge balance and realize zero voltage switching-on（ZVS） of switching device.The more accurate design equation of critical magnetizing inductance is derived according to electric charge balance on the basis of accurate calculation of electric charge supply.Finally, a prototype is build ,and the resonant tank is designed respectively based on the traditional and improved method.The comparison of experimental results verify the feasibility of the improved method in realizing ZVS of switching device.