Amplitude Modulation Index Based Equation For Predicting Total Harmonics Distortion In Seven Level Cascaded H-Bridge Inverter

This research work focuses on developing an amplitude modulation index based equation that can predict the harmonic content in the conventional seven-level cascaded H-bridge multilevel inverter CHBMLI at low switching frequency. A logic circuit using phase opposition disposition pulse width modulation PODPWM scheme is used for the seven-level CHBMLI. The multilevel inverter MLI is simulated for amplitude modulation indices from 0.10 to 0.26.The simulated and calculated results of the harmonic content in the output voltage at amplitude modulation index of 0.20 produce minimum values of 16.61 and 13.00 respectively. The harmonic content from the amplitude modulation equation on average deviates from the simulated result by 2.74 . Simulation results are obtained using MATLABSIMULINK software.