Seven-Level Common-Ground-Type Inverter With Reduced Voltage Stress

Transformer-less inverters (TIs) are widely used in solar photovoltaic (PV) applications due to their high power density, low dv/dt stress, low cost, and higher efficiency. The fundamental concern with TIs is the ground leakage current. This article proposes seven-level transformer-less common-ground (CG) inverter with a three-fold gain for synthesizing a seven-level output waveform using switched capacitors (SCs) with a single input source. Due to the CG connection, the proposed inverter can eliminate the ground leakage current. Also, the proposed topology requires a lower conducting devices, which minimizes conduction losses. The voltage across all of the SCs is self-balanced in every fundamental cycle. Therefore, the need for sensors and complex control circuits is eliminated. In addition, the operating modes, SCs design, and power losses are discussed in detail.  Furthermore, the experimental results are presented to verify the proposed topology’s theoretical concept, grid-operation, and feasibility. Finally, an exhaustive comparative analysis against state-of-the-art topologies is carried out to highlight the proposed topology’s benefits.