Analysis of integrated storage and grid interfaced photovoltaic system via nine-switch three-level inverter

This paper focuses on the modeling, controller design, simulation and analysis of a two-string photovoltaic (PV) and storage system connected to grid via a centralized nine-switch three-level inverter. A circuit-based PV array model is presented for use. A boost converter is employed to enable PV to operate at its maximum power point. The storage system consists of a capacitor bank connected at the DC bus via a full-bridge DC-DC converter. The centralized inverter is controlled by a decoupled current control technique and interfaced with grid via a transformer and double transmission lines. And three-level PWM is generated by applying two symmetrical triangular carriers. Three-phase voltage source and RL load are used for simulation. Eventually, the system stability is assessed with respect to fault conditions and solar irradiation change in simulation software PSCAD.