Three-Phase Photovoltaic Grid-Connected Inverter Simulation with Dual-Loop Control

This document explores the Simulink simulation of a three-phase photovoltaic grid-connected inverter system, with particular focus on dual-loop control of current and voltage. To establish foundational understanding, we first examine the fundamental principles of three-phase PV grid-connected systems. These systems convert direct current generated by solar photovoltaic panels into alternating current for injection into the power grid. The system configuration typically includes photovoltaic arrays, inverters, and the grid infrastructure. The inverter serves as the core component, responsible for DC-to-AC conversion while employing dual-loop control mechanisms to ensure output current and voltage stability. From an implementation perspective, the dual-loop control structure typically consists of an inner current loop for fast dynamic response and an outer voltage loop for steady-state regulation. In Simulink modeling, this can be implemented using PID controllers with appropriate tuning parameters. The current loop often utilizes dq-axis transformation for decoupled control, while the voltage loop maintains DC-link voltage stability through power balance calculations. Simulink simulation enables comprehensive analysis and optimization of this process through techniques such as Maximum Power Point Tracking (MPPT) algorithms, PWM generation modules, and grid synchronization controls. The simulation environment allows for testing of different control parameters, fault conditions, and system performance under varying irradiation levels, ultimately contributing to enhanced system efficiency and reliability.