Enhanced predictive control for nine-level packed U-cell inverter in grid-tied PV systems

To ensure grid stability and efficient power conversion, advanced inverter technologies play a crucial role in integrating photovoltaic (PV) systems into the electrical grid. The article suggests a photovoltaic system which is connected to the grid utilizing a nine-level Packed U-Cell (PUC9) topology, which incorporates a PV panel coupled with a DC-DC boost converter. This setup is managed by a Maximum Power Point Tracking (MPPT) algorithm, specifically using the Perturb and Observe (P&O) method, to optimize energy output by adjusting to varying irradiance and temperature conditions. The PUC9 inverter is designed with four pairs of complementary switches, one DC source, and two flying capacitors, and connects to the grid via a filtering inductor. This topology generates nine distinct voltage levels with fewer active and passive components than traditional multilevel inverters, leading to improved output quality and reduced total harmonic distortion (THD). The study assesses the performance of an advanced Finite Control Set Model Predictive Control (FCS-MPC) approach, comparing it to a traditional Proportional-Integral (PI) Pulse-width Modulation (PWM) method. While PI-PWM is recognized for its straightforward design and simplicity in application, it often struggles to maintain consistent performance under variable conditions due to its dependency on fixed control parameters. In contrast, the FCS-MPC approach offers dynamic response and better adaptability, which are essential for effective power conversion and system stability. Simulations conducted in MATLAB/SimulinkTM prove that the suggested MPC method provides improved tracking accuracy for maximum power points under changing irradiance conditions while maintaining efficient integration of power into the grid. The findings underline the potential of the PUC9 topology combined with the FCS-MPC strategy to provide high-quality output with improved robustness and resilience, making them viable solutions for contemporary renewable energy applications.