Evolutionary computing based area integration PWM technique for multilevel inverters

Abstract

When utilized at low switching frequencies, existing multilevel carrier-based pulse width modulation (PWM) strategies have no special provisions to render the quality output, and several lower order harmonics are included in the spectrum. This paper proposes a novel multilevel PWM strategy to have the advantages of low frequency switching and reduced total harmonic distortion (THD). The basic idea of the proposed area integration PWM (AIPWM) method is that the area of the required sinusoidal (fundamental) output and total area of all the pulses in every half cycle are same. The rationale for opting AIPWM is easy implementation of the control scheme in real-time digital platform. An additional crux objective of this paper is evolutionary computing based placement of the AIPWM pulses. The same is fulfilled by two soft computing techniques namely Evolutionary Programming (EP) and Genetic Algorithm (GA). A prototype seven-level cascaded inverter has been built and controlled with the novel PWM strategies.