一种谐振开关电容变换器的再分析与改进

Analysis and Improvement of a Resonant Switched Capacitor Converter

针对一种常见的谐振降压式开关电容直流变换器,使用近似取值方法进行再分析,简化了以往理论分析结果,并指出该电路存在的一些问题。由此提出了一种恒流充电谐振放电工作方式的新式改进电路,在该电路工作的任意时间内,导通的开关器件总处于有电流状态,避免了开关器件的导通电流在时间上分布过于集中,因而降低了电路峰值电流,提高了变换效率。通过推导,得出新改进电路的输出电压、变换效率及谐振平均电流的数学表达式,最后进行了实验验证。理论与实验均表明,新改进电路能在较大范围内进行近似线性的调频方式调压,为高效率谐振式开关电容直流变换器的设计提供了理论依据。

Based on the approximated value method, this paper analyzes a common step-down resonant switched capacitor direct current converter circuit in order to resolve the problems existed in this circuit, such as large peak current, on-state power losses and sneak circuit. A new and improved resonant switched capacitor converter by changing the resonant capacitor charging duration to adjust the output voltage is introduced. Through the comparison of theoretical analysis and test results of the output voltage, conversion efficiency, average resonance current and other factors of the new designed circuit, the improved circuit could adjust the output voltage in a wider range through the frequency modulation in an approximated linear way. This study provides a theoretical basis for the design of high efficient resonant capacitor converter circuit.