An Optimized Phase Shifted PWM for Flying Capacitor Multilevel Converter

A novel modulation method is presented in this paper to reduce the voltage ripple of the Flying Capacitors (FC) in the Flying Capacitor MultiLevel (FCML) converter. The scheme is based on the modification of the conventional Phase-Shifted PWM (PSPWM) method. The new scheme reduces the required capacitance, given the same voltage ripple constraint, compared to traditional PSPWM. A Variable Frequency Phase-Shifted PWM (VF-PSPWM) scheme is presented that varies the frequency of the carrier signals based on the magnitude of the load current. The decreased voltage ripple reduces the capacitance requirement in the design leading to higher power density designs. Simulation and experimental verification are provided to support the proposed VF-PSPWM scheme.