Harmonic Reduction in Reduced Power Switch Multilevel Inverter Using Genetic Optimization

In the recent years, the requirement of multilevel inverter is expeditiously increasing in the field of electrical energy utilization. Because the multilevel inverter is a key technology to integrate the renewable energy sources with the grid. Recently, various multilevel inverter topologies have been introduced which required a large number of power switches, gate drive circuit and voltage sources, as a result the complexity of the circuit, power losses and voltage stress on switch increases on the other hand the efficiency of the system reduces. It also produces power quality issues at the generating and distributing utility end. In this paper, a new topology of multilevel inverter with reduced number of power switches and dc voltage sources are presented. The proposed topology has been designed to 9-level inverter with eight unidirectional, one bidirectional and two dc voltage sources. The proposed topology comprises of a H-bridge which synthesize a ac voltage by utilizing almost all possible additive and subtractive cases of the voltage sources with its combinational power switches. The researchers generated optimal switching angles using selective harmonic elimination technique with Genetic Algorithm to reduce the lower order harmonic present in the output voltage of the proposed nine-level inverters. MATLAB/ SIMULINK tool has been used to validate the proposed topology results on various load. The harmonic analysis of nine-level multilevel inverter for R-Ioad and RL-load through analysis by simulation. The proposed topology offers a high-power quality output with THD less than 5% and individual harmonic less than 3% as per the recommendation of IEEE 519.