Three-Phase Cascade H-bridge Inverters: A Comparative Study of GOA and FGOA for Selective Harmonic Elimination

This paper presents the use of improved Grasshopper optimization Algorithm (GOA) known as the Faster Grasshopper optimization Algorithm (FGOA), that is based on nature-inspired optimization algorithms for calculating the optimal switching angle to apply a 3-phase, cascaded H-bridge multilevel inverter. The optimized switching angles are calculated based on the best cost function formulated using the concept of the SHEPWM method to achieve an optimized output voltage with the desired fundamental voltage and minimize the low-order harmonics in the output produced by the multilevel inverter. The programmed simulation results show that the algorithm produces optimal switching angles for different modulation indexes than traditional techniques like the Newton-Raphson method and also gives a lower cost function comparable to GOA. MATLAB/SIMULINK performed on a three-phase, 5-level, 7-level and 9-level Cascaded H-bridge multilevel inverter are used to produced the staircase output waveform with the desired fundamental voltage and minimized lower-order harmonics using FGOA-derived optimal switching angles. The simulation studies and the model developed results are compared to showcase the FGOA-optimized SHEPWM outperforms comparable GOA in terms of convergence time, Fitness function, and THD.