Comparison of Seven and Nine Level Flying Capacitor-Multilevel Inverter using Staircase and Stepped Modulation

Abstract

In this paper, a seven-level and nine-level flying capacitor inverter (FLI) is modeled and simulated. For the control of the switches, distinct multicarrier PWM strategies such as In Phase Disposition (IPD) PWM, Phase Opposition Disposition (POD) PWM and Alternative Phase Opposition Disposition (APOD) PWM are implemented by considering three reference signals, namely sine, step and staircase. Intensive simulation experiments are carried out under matlab/simulink environment and fundamental value and harmonics of output voltages of the seven-level FLI and nine-level FLI under different modulation conditions viz., IPD, POD, APOD are measured and compared. Simulation results illustrates IPD and POD technique gives a better output waveform with lower THD value than APOD technique.