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This article proposes a single-stage, seven-level (7L), switched-capacitor-based grid-connected inverter architecture with a common ground feature. This topology has the ability to boost the output voltage up to three times the input voltage. The proposed topology can diminish the leakage current in grid-connected photovoltaic (GC-PV) applications, and its capacitor voltages are self-balanced without any additional control strategies. The different operating modes are described in detail with their related mathematical expressions. The design of passive components and a detailed power loss analysis are presented. The merits of the proposed structure are demonstrated using a detailed comparative assessment. The grid-connected operation of the proposed inverter structure is simulated in the MATLAB/Simulink environment, and the results are presented. The laboratory prototype of 935 W is built and analyzed to validate the performance of the proposed structure.

The article discusses a nine-level switching capacitor-based common ground-type boost inverter for grid-connected photovoltaic applications. The proposed structure’s direct connection between the negative terminal of the input source and the grid neutral eliminates leakage current. The proposed topology uses eleven switches, two diodes, and three switching capacitors to produce a double voltage boost with nine different voltage levels. Self-balancing switching capacitors eliminate the need for sophisticated independent control algorithms. The maximum voltage stress on one of the three capacitors equals the input voltage, while it is equal to half of the input voltage on the other two switched capacitors. The various modes of operation and capacitance calculation are discussed in depth. A comprehensive comparison with various nine-level topologies has been conducted in terms of total component count, total standing voltage, capacitor voltage, and approximate cost to demonstrate the proposed topology’s benefits. A 400-W inverter prototype is constructed, and the experimental findings under various operating situations are reviewed.

This article presents a new nine-level common ground (CG) type transformerless inverter (TL) structure with an integrated boost (IB) cell. The proposed structure eliminates the leakage current due to the CG structure between the input source and the grid neutral. The proposed topology is derived by combining a DC-DC boost converter and switched capacitor (SC) cell, capable of generating the nine-level output voltage over a wide range of input voltage variations. By maintaining the duty cycle of the IB converter switch at 50%, the proposed topology generates the output voltage with a boosting factor of 4. Besides, soft charging of the involved SCs and reduced inrush current is also achieved through the inductor, which ensures the permissible current stresses of the power switches. Furthermore, the voltage across the SCs is self-balanced, eliminating the need for complex independent control techniques. A 725-W laboratory prototype is built to test the performance of the proposed topology under various operating conditions, such as input and load variations. The measured efficiency of 96.9% at 725 W is obtained and is comparable with the simulation efficiency. Finally, the merits of the proposed topology are highlighted using a detailed comparison with the other recent nine-level inverter topologies. [ABSTRACT FROM AUTHOR]