A Switched-Capacitor Asymmetrical-Input Eleven-Level Inverter With Zero Leakage Current for PV Applications

In photovoltaic applications, multi-source transformerless inverters pose a leakage current issue due to the absence of galvanic isolation, presenting a structural design challenge. This paper proposes a switched-capacitor eleven-level inverter featuring an asymmetric input configuration and common-ground structure. The asymmetric design allows the inverter to accommodate PV panels of varying specifications, while the common-ground connection effectively eliminates the leakage current. With the series and parallel operation, the voltage of all capacitors is naturally self-balanced without any voltage sensors. Furthermore, the generalized structure of the proposed inverter accommodates a variable number of input sources while maintaining its common-ground configuration, thereby enhancing flexibility and safety. Meanwhile, the reliability of the system has also been verified and enhanced when any input voltage source failed. Compared to existing structures, the proposed inverter requires fewer power devices, demonstrates higher boosting capability, appropriate costs, improve reliability and effectively addresses the leakage current issue. Besides, the nearest level modulation strategy, system parameter designs, and power loss analysis are given. Finally, the feasibility of the proposed structure and control strategy are verified through simulation and experimental results, confirming its dynamic stability under off-grid conditions and reactive power support capability under on-grid conditions.