Calculation of Optimal Switching Angles for a Multilevel Inverter Using NR, PSO, and GA- a Comparison

Abstract

Currently, multilevel inverters have been increased the number of applications in the industrial sector and renewable energy sources. Among its characteristics, the most remarkable are modular design, high performance, and low harmonic distortion in the output voltage waveform. For this paper, a single-phase Cascade H-Bridge Multilevel Inverters (CHB-MLI or CMLI) topology with independent DC sources, has been selected for the case study. Analyzing three scenarios: 5-level, 7-level, and 9-level applying the concept of the Optimized Harmonic Stepped-Waveform (OHSW) and comparing the results between the Selective Harmonic Eliminated-Pulse Width Modulation (SHE-PWM) and the Optimal Minimization of the Total Harmonic Distortion (OMTHD) are also presented. To compare the results obtained with classical and nature-inspired optimization methods, three techniques are used to solve transcendental nonlinear equations for the problem of Total Harmonic Distortion (THD) minimization: Newton Raphson (NR), Genetic Algorithm (GA), and Particle Swarm Optimization (PSO), which have been widely used for the problems of THD minimization in multilevel inverters.

Optimization of the Voltage Total Harmonic Distortion in Multilevel Inverters by Using the Taguchi Method

“…The authors of [35] use the exact MATLAB GA solver that is used in this paper; however, the authors do not state how the GA parameters were chosen. This THD value reported in this paper was lower in both cases, and the results were obtained experimentally.…”

Harmonics Minimization of Symmetric Five-Level Inverter Using Improved LSF Modulation Scheme

“…• The dominate THD is observed at lower frequency that requires high filter size. [18], [19] Half Height Method…”

Total Harmonic Distortion Reduction in Multilevel Inverters through the Utilization of the Moth–Flame Optimization Algorithm

“…Numerous articles have tackled the optimization of the THD for the output voltage in the Cascade H-Bridge Multilevel Inverter Topology (CHBMLI) by obtaining and implementing the switching angles that generate the voltage output waveform by using low-frequency modulation [11][12][13][14][15][16]. The obtention of the switching angles is primarily carried out using Selective Harmonic Elimination (SHE) and the Optimal Minimization of the Total Harmonic Distortion (OMTHD).…”

“…On the other hand, the OMTHD technique also allows for obtaining the switching angles of a CHBMLI; however, the objective of this function is to directly reduce the THD in the output voltage pattern of a CHBMLI, and, compared to the SHE method, the OMTHD manipulates the value of the harmonics without maintaining or eliminating any specific harmonics (including the fundamental component) [11].…”

“…The OMTHD method has been carried out using conventional techniques like the NR method [11,15], where the authors obtained the THD values for the CHBMLI across configurations of five, seven, and nine levels. However, many authors have been using metaheuristic algorithms just as in the SHE method.…”