一种新型降压谐振开关电容变换器

A New Step-down Resonant Switched Capacitor Converter

针对开关电容与二次型Buck变换器相结合形成的二次型开关电容Buck变换器(SC-QBC)存在开关管电压应力大、效率低的问题,提出了一种新型降压谐振开关电容变换器。该变换器是在SC-QBC的基础上,通过增加谐振电感、二极管和电容元件得到。与SC-QBC相比较,在降压特性变化不大的情况下,新型变换器的开关管的电压应力变小;增加的谐振电感通过与开关电容谐振,使第2级实现了开关管的零电流关断(ZCS),减小了开关损耗,提高了开关管的工作频率,有利于变换器的重量和尺寸的减小;同时,谐振回路上的二极管都能实现零电流关断,减小了二极管的反向恢复损耗。这些优点有利于器件的选择和效率的提高。最后,通过实验验证了理论分析的正确性。

The step-down converter(switched-capacitor quadratic Buck converter,SC-QBC),which is composed of switched capacitor and quadratic Buck converter,has the problems of high voltage stress and low efficiency.In order to solve these problems,a new step-down resonant switched capacitor converter was proposed.Based on the SC-QBC,the converter was obtained by adding a resonant inductor,a diode and a capacitor.Compared with the SC-QBC,the voltage stress of the switch was reduced with little change on the conversion ratio.By adding a resonant inductance resonates with the switched capacitor,the zero current switching(ZCS)of the switching was realized in the second stage and the switching loss was reduced,the working frequency of the switch which is helpful to reduce the weight and size of the converter was improved.At the same time,all diodes on the resonant circuit could be switched off with zero current,alleviated the reverse-recovery losses of the diodes.These advantages make component selection for the proposed converter much easier and the efficiency improved.Finally,the experiment was built to verify the theoretical analysis.