A Generalized Unit-Cell-Based Multilevel Inverter with Reduced Components, Low THD, and Scalable Output Voltage Levels

Multilevel inverters (MLIs) have been widely employed in modern power conversion systems because of their enhanced output voltage quality, reduced voltage stress, and lower total harmonic distortion (THD). This paper presents a generalized unit-cell-based multi-source multilevel inverter topology capable of generating scalable output voltage levels through the cascading of identical unit cells. The proposed topology is developed and evaluated for 15-level and 31-level configurations using only 8 switches with 3 DC sources and 10 switches with 4 DC sources, respectively. Optimum Nearest Level Modulation (ONLM) is employed for generating the required switching pulses. The proposed configurations are validated through MATLAB/Simulink simulations under resistive, RL, and dynamic load conditions. The obtained voltage THDs are 5.39% and 4.71% for the 15-level and 31-level configurations, respectively. The results demonstrate that the proposed topology offers reduced component requirements, low harmonic distortion, and flexible scalability, making it a promising solution for high-quality power conversion applications.