Elimination of Lower Order Harmonics in Multilevel Inverters Using Genetic Algorithm

This project presents the Genetic optimization method for harmonic elimination in a cascaded multilevel inverter and an optimal solution for eliminating pre specified order of harmonics from a stepped waveform of a multilevel inverter topology with equal dc sources. The main challenge of solving the associated non linear equation which are transcendental in nature and therefore have multiple solutions is the convergence of the relevant algorithm. The main objective of selective harmonic elimination pulse width modulation strategy is eliminating low-order harmonics by solving nonlinear equations. The performance of cascaded multilevel inverter is compared based on computation of switching angle using Genetic Algorithm as well as conventional Newton Raphson approach. A significant improvement in harmonic profile is achieved in the GA based approach. A nine level cascaded multi level inverter is simulated in MATLAB/Simulink and a hardware model has been fabricated to validate the simulation results. Keywords-Genetic Algorithm (GA), Multilevel inverters, Selective harmonic elimination (SHEPWM).