Modulation index regulation of a multilevel inverter for static var compensation

A strategy is presented to minimize the voltage total harmonic distortion when controlling a multilevel converter to act as a static var compensator. Use of resultant theory has enabled the complete set of solutions to be found for switching a multilevel inverter´s power electronic devices at the fundamental frequency while eliminating the lower order harmonics. A scheme is also presented to regulate the voltage levels of the multilevel inverter so that it operates in an optimum amplitude modulation index regime.