Abstract:
A multilevel inverter is a power electronic device for AC voltage level at output by multiple lower level DC voltages as input. The usage of multilevel inverters is increased since last decade. Total harmonic distortion (THD) of output voltage in multilevel inverters is reduced by optimal switching angle selection. But in existing methods, THD was not lessened to improve the output voltage performance. In order to address the above mentioned problem, Nature-Inspired Enhanced Memetic Optimization based Selective harmonic elimination (NIEMO-SHE) method is introduced in multilevel inverters. The key objective of NIEMO-SHE method is to identify the optimal switching angle for Selective harmonic elimination (SHE) in multilevel inverter. NIEMO-SHE method exploited the memetic optimization algorithm for finding the optimized switching angle to enhance the output voltage performance in multilevel inverter through eliminating the harmonic distortions. The multilevel inverter is designed and modulation index is computed. Then, the switching angles of multilevel inverter are calculated and the population of switching angle is initialized randomly. The memetic fitness function is measured in NIEMO-SHE method to perform the selection, crossover and mutation operation. Roulette wheel selection is carried out in NIEMO-SHE method to select the individual (i.e., switching angle) from the population after satisfying the memetic fitness function criterion. Then, ring crossover operation is performed to create new adapted ones for identifying the near optimal switching angles through performing the swapping process. Finally, adaptive levy mutation operation is carried out in NIEMO-SHE method for newly generated individuals to find the optimal switching angle. The process gets continual until criterion gets satisfied. By this way, the optimal switching angle is selected in NIEMO-SHE method for SHE with minimal time consumption and higher efficiency. Experimental evaluation of NIEMO-SHE method is carried out in terms of SHE time, SHE efficiency, and total harmonic distortion. The simulation results show that NIEMO-SHE method increases the performance of SHE efficiency reduces SHE time and THD when compared to state-of-the-art works.
