APPLICATION OF CURVE FITTING TECHNIQUES USING SOFT COMPUTING TECHNIQUES (GA, GSA, POS AND NR) IN MULTILEVEL INVERTERS FOR HARMONIC MINIMIZATION

Abstract

With the advent of low cost and powerful computers, the soft computing (SC) approach seems to be a better approach and well suited to handle the complexity of the HEPWM problem. This paper presents an approach to the application of soft computing techniques for selective harmonic elimination from output voltage of Single phase multilevel inverter by proper selection of switching angles. Newton Raphson method (NR), Genetic algorithm (GA), Particle swarm optimization (PSO) & Gravitational search algorithm (GSA) are prominent soft computing techniques which are implemented to obtain the minimum total harmonic distortion (THD) of multilevel inverter. To obtained experiment results a new modulation method is used to change these angles into PWM switching. Another approach in the determination of switching angles for Selective Harmonic Elimination technique of reduction of harmonics is the use of Curve Fitting technique has been reported. Some new curve fitting techniques mainly piecewise curve fitting technique using spline has been worked out and analyzed. Comparison of performances of soft computing and curve fitting techniques is done. Simulation and experimental results prove the powerful merits of the proposed techniques and improvements done on previous works.

Keywords

• Multilevel inverters
• Selective harmonic elimination
• Total harmonic distortion
• PWM switching
• curve fitting
• SPLINE