A single-source nine-level solar-PV inverter with quadruple voltage boosting and high reliability

An increase in generation from distributed energy sources like solar PV has motivated researchers to explore better electrical energy conversion solutions. Multilevel inverters with fewer component count and boosting capabilities contribute to a reliable and efficient single-stage solution. This work proposes a reliable single-source switched capacitor multilevel inverter capable of producing nine-level boosted AC voltage with its stand-alone and grid-connected operation. It employs 11 switches, three diodes, and three switched capacitors. The main feature of the proposed topology is its ability to produce quadruple boosting with respect to the DC input voltage. Another advantage is the exhibition of low capacitor currents due to frequent charging durations in one operational cycle. The selection criterion for the switched capacitors is also presented. The topology's performance is evaluated in MATLAB/Simulink under various conditions and in PLECS environments for its efficiency. It was then realized on an experimental prototype in stand-alone mode. The topology is then modified in terms of topology and modulation to mitigate the leakage current, thus making it suitable for grid-connected operation. This operation is validated on the hardware-in-the-loop platform. Further, the reliability analysis explores a high total mean time to failure (MTTF_T) of nearly 253,164 hours/failures compared to recent switched capacitor topologies and an efficiency of above 95%. The low inrush currents, high MTTF_T value, and better efficiency make it a suitable topology for renewable microgrids' stand-alone and grid-integrated operation.