Indian Journal of Science and Technology

Abstract

Objectives: This paper deals with the reduction of THD (Total Harmonic Distortion) in the voltage output waveform of a four-stage monophasic cascaded multilevel inverter with Multiple-Carrier Sine Pulse Width Modulation (MCSPWM) using the Simulated Annealing Optimization (SAO) technique. Method: The SAO algorithm was employed to calculate the appropriate firing angles for the switching devices of the inverter by mean of finding the best symmetry of the triangular wave, its frequency and the amplitude of the sine wave used in the modulation through of MATLAB. The monophasic multilevel inverter was simulated and evaluated using de SAO algorithm, then, a prototype was implemented for validating the results. Findings: The output waveform of the converter for multiple scenarios, the graphic of the harmonic content and the optimized modulation parameters were obtained in both the simulation and the prototype. The Simulated Annealing algorithm allowed to find the appropriate firing angles for the four-stage multilevel inverter, adjusting the optimal parameters of triangular and sine signals used in MCSPWM modulation, leading to obtaining a low harmonic content in the output waveform (THD less than 5%), using a low number of switching devices. Novelty/Improvement: The proposed technique (Simulated Annealing) permits to find the optimal parameters of modulation waveforms through a heuristic approach avoids the possible issues with local minima. Also, the method applied optimizes the number of necessary switching devices. 

Keywords: Multilevel Inverter, Multiple Carrier SPWM, Simulated Annealing, THD