OPTIMAL SHE-PWM FOR VOLTAGE SOURCE MULTILEVEL PWM INVERTERS

Abstract: In recent years, cascaded H-bridge multilevel inverters (CHB-MLI) are widely accepted in various industrial applications. Higher switching losses are one of the major concerns in the pulse-width modulation (PWM) techniques for CHB-MLIs. Selective harmonic elimination PWM (SHE-PWM) offers low switching losses owing to lower switching frequency. This dissertation aims of providing an efficient optimization technique for SHE- PWM based CHB-MLI. As this method is based on optimization algorithms, the switching angles are obtained without solving the non-Linear transcendental equations arithmetically. Comparative study is planned to find out efficient optimization technique for SHE-PWM equations. For validation, 7, 9-and 11-level inverters are to be selected and MATLAB software is being used for optimization and CHB-MLI simulation. The best suitable optimization technique shall be used in further research studies.

Keywords: Total harmonic distortion-THD, CHB-MLI-Cascaded H Bridge Multilevel Inverter, SHE-PWM- Selective Harmonic Elimination pulse width modulation, GA-Genetic Algorithm, PSO-Particle Swarm Optimization, FFT-Fast Fourier Transform.