Flying-inductor-cell based inverters for single-phase transformerless PV applications

The application of the general flying-inductor (FI) cell in two novel transformerless photo-voltaic (PV) inverters are proposed and investigated. The simultaneous step up and down ability is possible with both topologies, while a high conversion efficiency and a high-quality AC current are achieved. The leakage current problem, which is a main concern with the transformerless PV inverters, is also considered. One of the proposed topologies presents a higher efficiency, while the other one provides the high quality of injected current with the lowest number active switches. The current control, especially at transition modes of operation is highly improved by utilizing a fast response dead-beat control scheme. The working principles of the proposed converters are explained in details and 0.88-kW experimental prototypes are implemented to confirm the theoretical achievements. Finally, a comparison with other existing topologies has been investigated for better clarification of the advantages and disadvantages of the proposed inverters.