A Single-Stage Common Ground Type Transformerless Five-Level Inverter Topology

In solar photovoltaic (PV) inverters, a separate boost converter is often used to boost the input voltage, increasing the number of components, cost and weight of the systems and losses. To address this issue, a new common ground type (CGT) transformer-less five-level (5L) switched capacitor inverter topology with integrated boost converter is presented in this paper. The proposed topology is capable of soft-charging the floating switched-capacitor (SC) and has reduced component count. The careful amalgamation of the inductor-based boosting and SC-based boosting results into a higher gain. Unlike the existing CGT 5L inverters, the proposed topology provides a charging state for the SC in every switching cycle for 5L operation. The benefits of proposed topology are highlighted and compared with the other recent switched-capacitor inverter topologies. The detailed operation of the proposed topology is supported with necessary mathematical analysis. The simulation and experimental results are presented to validate the feasibility of the proposed topology.