Three-Phase Multilevel Inverter with Minimized Low-Order Harmonics Using Mantis Search Algorithm

In this paper, the mantis search algorithm (MSA), is proposed to determine the switching angles for a three-phase (3-ph) eleven-level (11-lvl) cascaded H-bridge multilevel inverter (CHBMLI). MSA is applied to the selective harmonic minimization pulse-width modulation (SHMPWM) technique to maintain the desired fundamental harmonic while minimizing undesired low-order harmonics. The performance of the MSA-SHMPWM technique is compared to that of a well-known optimization algorithm, the genetic algorithm (GA). For fair comparison, both GA- and MSA-SHMPWM techniques are implemented in MATLAB with the same population size, maximum number of iterations and maximum number of runs. Furthermore, a 3-ph ll-lvl CHBMLI is modeled using PSIM simulation software to validate the effectiveness of the MSA-SHMPWM technique. The MATLAB analysis results show that the MSA-SHMPWM technique achieves a minimum objective function (OF) values of 10–<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">19</sup>, which is lower than the 10–<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">9</sup> achieved by the GA-SHMPWM technique. This indicates that the MSA-SHMPWM technique determines switching angles with higher accuracy compared to the GA-SHMPWM technique. Additionally, the PSIM simulation results confirm that the switching angles determined by the MSA-SHMPWM technique, when applied to a 3-ph ll-lvl CHBMLI, generate sinusoidal staircase-like output phase and line-to-line voltage waveforms with the desired fundamental voltage and minimized undesired low-order harmonics. The total harmonic distortion (THD) of these voltage waveforms, when the CHBMLI is operated at modulation index of 0.60, are 36.61 % and 7.24 %, respectively.