Selective Harmonic Elimination In Cascaded H-Bridge Multilevel Inverter Using Genetic Algorithm Approach

Multilevel inverters are worked on medium-voltage and high-power applications due to their ability to supply high power quality output voltage. Hence, a low switching frequency strategy is applied in high power applications since it generates lower magnitudes of harmonics than high switching frequency. In this paper, to eliminate high selective harmonic in a 15-level cascaded multilevel inverter, a genetic algorithm approach is proposed. Genetic algorithm is an evolutionary algorithm to determine switching angles 15-level cascaded multilevel inverters in order to eliminate selective harmonic. This paper calculates the optimum angles as offline to eliminate harmonics 3^rd, 5^th,7^th, 9^th, 11^th, 13^th, 15^th and 17^th along with their multiples. Then, the obtained angles are applied to simulation results to validate the approach performance.

I. Introduction

Multi-level inverters (MLI) are among the most selected power conversion devices in industrial applications. These applications mostly comprise motor drives for all voltage and power ratings. Multilevel inverters are also finding their applications in grid-connected systems, uninterrupted power supply (UPS), electric vehicles and FACTS devices. All these applications are possible due to the ability of the MLI to provide a superior output voltage with a more sinusoidal shaped waveform, improved efficiency due to lower switching frequency operation of switches, lower blocking voltage requirement with reduced dv/dt and improved electromagnetic compatibility [1], [2].