Improved power factor in a low-cost PWM single phase inverter using genetic algorithms Erhan Butun a, * , Tarık Erfidan a , Satılmıs Urgun b a Electrical Engineering Department, Faculty of Engineering, Kocaeli University, Veziroglu Campus, Izmir, 41650 Kocaeli, Turkey b Civil Aviation College, Kocaeli University, Izmir, 41650 Kocaeli, Turkey Received 26 November 2004; received in revised form 18 July 2005; accepted 13 August 2005 Available online 28 September 2005 Abstract In this paper, a method for voltage harmonic elimination in a pulse width modulated (PWM), single phase inverter using genetic algorithms (GAs) is proposed. We explain the resolution method procedure of the non-linear equation sys- tems in order to achieve the appropriate switching angles. The output voltages with k pulses per half cycle are written in terms of switching angles using Fourier series, and the best switching angles are calculated off line to eliminate the third, fifth and seventh harmonics. Then problem is redrafted as an optimization task, and a solution is sought through GAs. For performance comparison with GAs, the Newton–Raphson method is also applied to the present problem. Comparison shows that the genetic algorithm method has some advantages such as a reduced computational burden, faster convergence and guaranteed global optima in most cases relative to the Newton–Raphson method. The developed analysis is experi- mentally verified by an experimental implementation. Ó 2005 Elsevier Ltd. All rights reserved. Keywords: Harmonic; PWM; Single phase inverter; Genetic algorithms 1. Introduction Ideally, electrical signals are purely sinusoidal, and all phenomena resulting in modifications of this ideal shape are referred to as disturbances. Harmonic disturbances are modeled by adding to the fundamental wave a series of periodic signals of pulsations whose frequencies are multiples of the frequency of the fundamental. Recent years have witnessed a multiplication in the number of polluting electrical loads responsible for the appearance of harmonic signals in electrical networks. The problem of reducing these disturbances in switch- ing converters has been the focus of research for many years. If the switching loses in an inverter are not a concern, then the sine triangle PWM method and its variants are very effective for controlling the inverter. On the other hand, for systems where high switching efficiency is of utmost importance, it is desirable to keep 0196-8904/$ - see front matter Ó 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.enconman.2005.08.010 * Corresponding author. Tel./fax: +90 262 351 33 11. E-mail address: ebutun@kou.edu.tr (E. Butun). Energy Conversion and Management 47 (2006) 1597–1609 www.elsevier.com/locate/enconman