Assessment and Prediction of Various Variable Amplitude Carriers for Multilevel Inverters

Abstract

 This paper discusses the role of variable amplitude carriers for symmetrical five level, binary seven level and trinary nine level inverter. Various variable amplitude carriers are proposed in this paper with different references like sine, third harmonic injection, 60 degree and stepped wave reference. The simulations are carried out using MATLAB/SIMULINK and hardware realization is obtained using FPGA (Field Programmable Gate Array). For all the PWM methods and references the UEAC (Un Equal Amplitude Carriers) produces less THD (Total Harmonic Distortion) for lower levels  and for higher levels the equal amplitude carriers are better and higher fundamental RMS (Root Mean Square) values for all the PWM strategies and references for UEAC. New variable amplitude PWM strategies have been developed using MATLAB-SIMULINK and tested for different modulation indices ranging from 0 - 1 for the chosen single phase MLI (Multi Level Inverter) and then implemented in real time using FPGA (Field Programmable Gate Array). The simulation and experimental results are satisfactory.