A simplified space vector PWM for cascaded H-Bridge inverter including over modulation operation

Abstract

This paper presents a simplified space vector pulse width modulation method for multilevel inverters. In this method, the desired switching states of the reference voltage vector and switching time calculations are done online through generalized simple expressions without any predetermined data in the memory lookup table. The proposed method is also extended for over modulation region by incorporating the concept of reference voltage vector and ON-time modification. This new control method is attractive in terms of reduction in computational complexity, minimization of voltage and current THD and the extension of range for over modulation operation; the simulation has been carried out for cascaded H-Bridge five level inverter including over modulation range using MATLAB/Simulink. The hardware implementation of the proposed method has been done using XILINX SPARTAN-3A FPGA Processor. The simulation waveforms validate the harmonic analysis of voltage and current at different modulation index.