A modulation method for capacitor voltage ripple reduction of the switched-capacitor inverter using series/parallel conversion

A modulation method for capacitor voltage ripple reduction of the switched-capacitor inverter using series/parallel conversion (SCISPC) is proposed. The phase shifted pulse width modulation (PWM) method and the level shifted PWM method are applied to the proposed modulation method. The two capacitors in the 7-level SCISPC is charged alternately by this modulation method. The voltage ripple of these capacitors can be small because the discharging term becomes short. The switching frequency of the proposed modulation method can be reduced. The high efficiency power conversion of the SCISPC is achieved because of the low voltage ripple of the capacitors. The effect of the proposed modulation method is confirmed by the simulation with PSIM and the circuit experiment. The voltage ripple reduction of the capacitors is 33.7% in the simulation result.