Optimal THD Reduction in Multilevel Inverters Using PID and Fuzzy Logic Control

Abstract

Multilevel inverters (MLIs) are becoming essential for most high-voltage, high-power, and medium-voltage electronic applications. MLIs offer a range of output levels suitable for satisfying the varied demands of high-voltage and power applications. Besides enhancing output levels, MLI can reduce voltage stress (dv/dt) and the total harmonic distortion across the power switches. The extensive advancement of new MLI topologies on current ones enhances the ability to increase output levels while utilizing fewer components. Three significant topologies of multilevel inverters are compared in this work: cascaded H-bridge inverters, diode-clamped inverters, and flying capacitors. Electromagnetic interference (EMI) and total harmonic distortion results are compared. To do this comparison, meticulous MATLAB/Simulink simulations are used to analyze these inverters. Three configurations of inverters are simulated. There are three types of phases: single-phase, three-level, and five-level. Based on the comprehensive MATLAB/Simulink simulation results, a comparison of the efficacy of these multilevel inverters is possible. Alongside conducting a comparative analysis of established topologies, Traditional multilevel inverter designs frequently encounter complexity issues, highlighting the need for a more simplified approach. This study introduces a novel structure known as the 'packed u-cell 5 ' within the MATLAB/Simulink software. Its THD characteristics are analyzed to assess the efficacy of this novel structure. By implementing PID control, the work also seeks to enhance the total harmonic distortion performance of the 'packed u-cell 5 ' structure. After that, we used a Fuzzy Logic Controller (FLC) with a Mamdani type. Simulation results show that the PUC inverter with the Fuzzy Logic Control successfully maintains the output voltage level within the desired range. Furthermore, to assess the superiority of the Fuzzy Logic Control, a comparative evaluation is conducted between the Fuzzy Logic Control and PID Control methods for the packed U-Cell 5 inverter. The results reveal that the FLC exhibits more consistent and reliable feedback compared to the PID controller. A comparative analysis of their total harmonic distortion and electromagnetic interference outputs was conducted via simulations in MATLAB/Simulink.