Voltage harmonic elimination in PWM A.C. chopper using genetic algorithm

A method of voltage harmonic elimination in a pulse-width modulated AC/AC voltage converter using genetic algorithms (GA) is proposed. The output voltage of the AC chopper with k pulses per half cycle is written in terms of switching angles using Fourier series, and the best switching angles are identified with the dual objectives of harmonic elimination and output voltage regulation. The problem is redrafted as an optimisation task, and a solution is sought through GAs. For performance comparison of GAs, other optimisation methods such as Rosenbrock's rotating coordinates method, the random search method and the Newton-Rasphson method are also applied to the present problem. Comparison shows that the genetic algorithm method is on a par with conventional optimisation methods. In addition, the GA approach has several advantages, such as a reduced computational burden, faster convergence and guaranteed global optima in most cases. The theoretical findings are verified through experimental results.