Selective Harmonic Elimination for Multilevel Inverters using Immune Optimization Algorithm

In PWM inverters control, selective harmonic elimination (SHE) technique is used to control fundamental harmonic and eliminate harmonics of chosen lower-order. However, PWM technique requires the determination of the optimum switching angles by solving nonlinear transcendental equation set. Recently, meta-heuristic optimization techniques have shown remarkable performance in solving various complex engineering problems. In this paper, an improved immune optimization algorithm (IAIA), based on the model of biological immune system, is proposed to solve SHE problems for multilevel inverter. In numerical experiments, a 7-level inverter is considered to evaluate the performance of the IAIA and it is also compared to GA in terms of the convergence and the total harmonic distortion (THD) under different modulation indexes. The results indicate that IAIA achieves competitive performance than GA do on most of the modulation indexes.