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Photovoltaic (PV) string inverters with transformerless grid-connected architecture are the most commonly used solar converters owing to their appliancefriendly and cost-effective benefits. A novel circuit configuration for these converters is presented in this study, which seeks to address the shortcomings of most of the conventional topologies such as the problem of leakage current, voltage ratio transformations, and power quality. The proposed structure is based on the seriesparallel switching conversion of the switched-capacitor (SC) cell and is comprised of only six unidirectional power switches with a common-grounded (CG) feature. Through the use of the SC cell and the CG connection of active and passive used elements, not only is the number of output voltage level enhanced by up to five but also a two times voltage boosting feature with a single stage operation as well as elimination of the leakage current is acquired. Herein, to inject a tightly controlled current into the grid, a peak current controller approach has been used which can handle both the active and reactive power supports modes.Theoretical analysis, design guidelines, comparative study, and some experimental results are also given to corroborate the feasibility and accurate performance of the proposed topology.

Transformerless grid-connected inverters have been extensively popular in renewable energy-based applications owing to some interesting features like higher efficiency, reasonable cost and acceptable power density. The major concern of such converters is the leakage current problem and also the step-down feature of the output voltage which causes a costly operation for a single stage energy conversion system. A new five-level transformerless inverter topology is presented in this study, which is able to boost the value of the input voltage and can remove the leakage current problem through a common-grounded architecture. Here, providing the fivelevel of the output voltage with only six power switches is facilitated through the series-parallel switching of a switched-capacitor module. Regarding this switching conversion, the self-voltage balancing of the integrated capacitors over a full cycle of the grid's frequency can be acquired. Additionally, to inject a tightly controlled current to the local grid, a peak current controller-based technique is employed, which can regulate both the active and reactive power support modes. Theoretical analyses besides some experimental results are also given to corroborate the correct performance of the proposed topology.