Design and Analysis of a Symmetric Seven-Level Inverter for THD Minimization with Reduced Component Count

The increasing demand for medium-power and high-voltage AC systems has established multilevel inverters (MLIs) as critical replacements for traditional two-level inverters in DC-AC power conversion. This research introduces a novel single-phase symmetric seven-level inverter architecture specifically designed for renewable energy applications. The main aim of the design is to reduce system complexity by reducing the number of conducting components and lowering the value of THD. The proposed inverter uses 3 separate DC voltage sources with equal magnitude for symmetric operations and 6 semiconductor switches to generate a seven-level output voltage waveform. Moreover, it reduces the switches' overall voltage stress. The suggested seven-level inverter's performance and viability are validated by the simulation results. The inverter resulted in a Total Harmonic Distortion of 1 1. 7 2 % without any filter circuit, which decreased to 1.37 % after a LCL filter was used, employing the Optimum Nearest Level Modulation technique.