谐振开关电容变换器(Resonant Switched Capacitorconverter RSCC)具有零电流开关的优点,但其输出电压的调节能力差.为了控制谐振开关电容变换器的输出电压,该文提出一种新型的PWM控制方式,它通过调整开关电容的充电时间(放电时间固定不变)来控制输出电压,使输出电压在输入电压和/或负载变化的情况下基本保持恒定.而且大部分开关器件仍保留零电流开关特性,因此具有开关电流应力低、EMI小等优点.该文以一个降压式谐振开关电容变换器为研究对象,详细分析了其工作过程和稳态特性,并制作了一台12V/5V/2A的实验样机控制系统,验证了该PWM控制方法的正确性和可行性.
Resonant switched capacitor converter (RSCC) has the advantage of zero-current switching, however, the regulation of output voltage is poor. A new PWM control method for RSCC is presented in this paper. In the proposed method, the discharging time is fixed and the charging time is variable, good output voltage regulation for large changes in input voltage and/or load values can be obtained by adjusting the ratio of charging time. Almost all switching devices keep zero-current switching. The proposed PWM scheme has the advantages of low switching current and low EMI. A step-down RSCC is used as an example in this paper. The circuit operation principle and steady-state characteristics are described in detail. A 12V/5V/2A prototype based on the proposed method has been implemented, theoretical prediction of its regulation is verified experimentally.