Design a multilevel inverter circuit based on different control structures

Multilevel inverters (MIs) offer significant advantages over traditional inverters by generating higher output voltages with fewer distortions, making them suitable for high-power applications. In this study, a MI circuit was presented that had been designed and implemented with ten switches and four asymmetrical DC sources. It is controlled by two different techniques to achieve a 31-level inverter output. The controllers utilize a modified absolute sinusoidal pulse width modulation (MASPWM) technique and a phase disposition, level-shifted-PWM (PDLSPWM) technique. The arrangement of the four DC sources is set at (1:2:5:10) volts of direct current (Vdc). The system's performance is evaluated in both with zero level state (WZ) and without zero level (WoZ) state. Comparative analysis of the circuit during WZ and WoZ states, based on the PDLSPWM and MASPWM controller techniques, is conducted. Simulation results in MATLAB indicate that the total harmonic distortion (THD) values of the output voltage and current using the PDLSPWM technique are 0.6676% and 0.166627% during WZ state, and 0.8435% and 0.2625% during WoZ state, respectively. Conversely, using the MASPWM technique, THD values are 0.643% and 0.0757% at WZ, and 0.90158% and 0.10209% at WoZ state. These findings confirm the efficiency of both controllers in conjunction with the proposed power circuit, particularly noting that the MASPWM controller yields better results in the WZ state. Overall, the results demonstrate the effectiveness of the proposed MI circuit and controllers in achieving desired output levels with minimal THD.