A Novel Asymmetric Nine Level Inverter with Reduced Device Count Suitable for Renewable Energy Applications

Multilevel inverters are widely used for renewable energy integration and many other industrial applications. Power quality, efficiency, and economy of the inverters are the prime importance common to all such applications. In this paper, a reduced component count asymmetric multilevel inverter is proposed. Compared to similar existing topologies, it uses a smaller number of active switches, diodes, and voltage sources. Its absence of dc-link capacitor ensures zero voltage unbalance problem. Selective harmonic elimination (SHE) PWM method is applied to reduce power loss, and total harmonic distortion (THD), thereby enhancing efficiency and power quality. The superiority of the proposed topology over the recently proposed similar topologies has been compared and verified. To validate the theoretical proposition, a nine-level asymmetric inverter is simulated in MATLAB/ SIMULINK environment. With a small LCL filter, the THD performance of the inverter is 0.81% which satisfies IEEE standards. Excellent dynamic load performance shows the suitability of the inverter for industrial applications.