Study of the Phase Shift Plus PWM Control Strategy Based on a Resonant Bridge Modular Switched-Capacitor Converter

Bridge modular switched-capacitor converter (BMSCC) has been reported with symmetric and modular structure, and featured less output voltage ripple, less components cost, and convenient voltage extension but weak output voltage regulation. This paper presents a phase shift plus pulse width modulation (PWM) control strategy for the novel resonant BMSCC. With this control method, output voltage regulation and the limitation of the loop peak current to a proper range are implemented. Also, output voltage ripple could be effectively controlled as well through the voltage ripple characteristics analysis in different cases. Detailed analyses of the relationships between the switching phases of MOSFETs and the output voltage, the switching-phases of MOSFETs and the loop peak current are performed. Meanwhile, through optimal switching sequence, the proposed control method ensures that almost all switching devices maintain zero current switching or zero voltage switching operation, which results in high system efficiency. Using simulation software of the saber and hardware platform, the soft switching, output voltage, and peak current characteristics are verified.