Advanced Control Strategy for Solar PV and Battery Storage Integration using a Three-Level NPC Inverter

Abstract

-This paper presents a grid-connected solar photovoltaic (PV) system integrated with battery storage, implemented using a three-level Neutral Point Clamped (NPC) inverter. A simplified Space Vector Pulse Width Modulation (SVPWM) technique for a three-phase, three-level inverter is proposed to enhance system performance. Compared to conventional two-level inverters, three-level inverters involve a larger number of switching states; however, the proposed method simplifies their implementation and control. The developed control algorithm manages power flow between the solar PV system, battery storage, and the grid, while also incorporating Maximum Power Point Tracking (MPPT) functionality to ensure optimal energy extraction. The proposed topology is capable of generating accurate AC output voltage even under unbalanced DC link voltage conditions through an efficient vector modulation approach. Additionally, the system effectively controls battery charging and discharging operations under varying levels of solar irradiation, ensuring efficient energy utilization. The complete system, including the three-phase three-level inverter with SVPWM control strategy, has been modeled and simulated using MATLAB/Simulink. Simulation results validate the effectiveness, stability, and performance of the proposed configuration in gridconnected applications.