Grid Integration of a Single-Source Switched-Capacitor Multilevel Inverter with Boosting Capability

This paper investigates the connection of a single-phase multilevel inverter structure to an existing power grid. The applied voltage source inverter is able to generate a near sinusoidal voltage waveform with an amplitude six times the input voltage by using a single DC input power supply. A proportional-resonant (PR) controller regulates the injected current into the grid. While the EPLL is used to ensure the synchronization of the phase and frequency of the output voltage with the grid. The performance of the grid-connected inverter under different loading conditions was simulated in MATLAB software. Finally, the simulation results were compared with the experimental ones. In addition, the behavior of the inverter in standalone operating mode supplying a local load as well as its performance in the grid-tied with a constant and variable current reference was evaluated. The correct operation of the inverter in all operating modes an achieving 96.9% efficiency along with the self-voltage balancing of the capacitors, makes it suitable for grid-integration of the low voltage renewable energy sources’ applications.