Weighted THD Factors Evaluation of Multilevel Voltage Source Inverter with Space Vector Control under Common-Mode Voltage Elimination

The harmonic distortion’s characteristics of the nearest-vector-selecting space vector control with common-mode voltage eliminating technique (CMVE-SVC) for three-phase multilevel voltage source inverter (MLVSI) are explored. The considered CMVE-SVC algorithm applies the particular MLVSI voltage space vectors, which produce the zero value of the common-mode voltage, i.e. the voltage across the load common point and the MLVSI common point. More specifically, the THD of the output phase voltage along with three its weighted THD of low orders are calculated in a virtual instrument of LabVIEW. The simulated dependences on the index of the amplitude modulation of the phase voltage are compared with the dependences of a recently proposed common-mode-voltage-eliminating space vector pulse width modulation technique. The importance of the considered weighted THDs for the load current THD assessment is noted.