Voltage source multilevel inverter voltage quality comparison under multicarrier sinusoidal PWM and space vector PWM of two delta voltages

Abstract

The three-phase multilevel inverter output voltage waveforms are compared for the recently proposed simple voltage source multilevel inverter space vector PWM technique, which uses the natural nonsymmetric three-segment vectors switching sequence, and for the traditionally applied in industry multicarrier sinusoidal PWM, namely the phase opposition disposition (POD) PWM. The two variants of the POD sinusoidal PWM technique with the opposite carriers phases are considered. The developed waveforms mathematical models were implemented in LabVIEW virtual instruments for simulation. The values of the total harmonic distortion (THD), the first order integral voltage harmonics factor and the zero and first orders indices of the so-called aggregate switchings and integrated voltage harmonics factors are presented as the functions of the amplitude modulation index for the five lowest values of the frequency modulation index. The simulation results have proved the clear superiority of the offered space vector PWM technique in the aggregate indices values.