A Three-Phase Hybrid Multilevel Inverter for Medium Voltage Applications

Multilevel inverters (MLIs) have gained significance for medium and high-power applications. Traditional topologies yield sinusoidal-like output voltages, but complexity escalates with higher output levels. Thus, research has focused on developing MLIs with reduced switch counts to simplify control while maintaining target total harmonic distortion (THD). This paper extends the application of a 1-phase hybrid MLI (HMLI) to 3-phase HMLI systems and incorporates an output filter to meet the THD requirements. The suggested 3-phase HMLI achieves 7-, 9-, and 11-level outputs without altering the base topology by controlling the sequence of switching operations. The 3-phase HMLI is compatible with battery and solar sources and suitable for medium-voltage applications. The performance is thoroughly validated using MATLAB/Simulink, including output filter analysis, various modulation index values, and modulation techniques (PD. POD. APOD) and different output levels.