Genetic algorithm based Selective Harmonic Elimination in PWM AC-AC converter

Abstract

Power Electronics is the field which combines Power, Electronic and Control systems. Power electronics deals with the study and design of Thyristorised power controllers for variety of application like Heat control, Light/Illumination control, Motor control — AC/DC motor drives used in industries, High voltage power supplies, Vehicle propulsion systems, High voltage direct current (HVDC) transmission. Due to these devices harmonics are produced. These harmonics leads to switching loss which affects the performance of the system. So the harmonics should be eliminated from the system. This paper proposes a technique to eliminate pre-specified order of harmonics from the output waveform of AC/AC converters. Selective Harmonic Elimination (SHE) in Pulse-width modulation (PWM) technique can be used for the elimination of harmonics which necessitates solving systems of nonlinear equations. The main challenge involved is to solve these nonlinear equations, which are transcendental in nature and therefore have multiple solutions. Genetic algorithm (GA) technique is introduced to minimize the computational burden associated with the nonlinear transcendental equations of the SHE-PWM method. The proposed algorithm could calculate switching angles efficiently resulting in fast convergence.