An Improved Switched-Capacitor-Based 13-Level Inverter for PV Applications

Transformer-less inverters (TIs) are commonly employed in solar PV systems because of their superior power density, reduced dv/dt stress, cost-effectiveness, and improved efficiency. This article proposes an improved SC-based 13-level inverter. This topology amplifies the input source voltage six times using switched-capacitors, enabling it to be utilized in medium-voltage, medium-power renewable energy source (RES) applications, such as PV and grid integration, where the input voltage source magnitude is lower. The proposed structure requires a single DC source, 12 switches, three diodes, and four capacitors for its successful operation. The system's overall efficiency, reliability, and power density are improved by the single-stage DC-AC power conversion, having fewer conducting components at each level. The charging loop contains only three devices, which reduces conduction loss. The capacitors are self-balanced without the need for extra control circuitry. A comparative analysis between the proposed topology and other recent topologies is presented to validate the performance of the proposed inverter. An evaluation of power losses in the inverter has also been carried out. Experimental testing and measurements are conducted to verify the performance of the topology under frequency variation, dynamic load changes, and modulation-index variations.