New Nine-Level Common-Ground Multilevel Inverter With Boosting Capability for Renewable Energies

In recent years, several common-ground switched-capacitor transformerless (CGSC-TL) dc–ac multilevel power converters have been introduced, providing advantages such as multilevel output voltage, voltage boosting, and mitigated leakage current. However, these structures mostly suffer from drawbacks, such as limited output voltage levels (like only five levels), lack of voltage-boosting capability, and high charging current spikes of the capacitors. This article proposes a new single-stage CGSC-TL nine-level (9L) multilevel inverter (MLI) with voltage-boosting capability and limited spikes of charging current of the capacitor, designed to be employed as a single-stage power-electronics-based interface device between renewable energy sources, such as photovoltaic (PV) systems and power grid and/or load. The proposed MLI provides several merits, such as a common-ground structure that suppresses PV-to-ground leakage current associated with PV parasitic capacitances, active and reactive power support, a wide input voltage range, and higher output voltage levels (9L) compared with other structures in the same class. Comprehensive comparative analyses, as well as simulation and experimental results, are presented to verify the performance of the proposed inverter.