Robust Control Under External Disturbances for Grid Tied Solar Generator: A Comparative Study

This paper investigates a three-phase grid-connected photovoltaic system equipped with battery storage and controlled through three different schemes: a conventional Proportional-Integral controller, a Twin Delayed Deep Deterministic Policy Gradient-based control method, and Linear Active Disturbance Rejection Control. Cascaded voltage and current loops are designed for the PV boost converter, the grid-side inverter, and the battery converter. The control system is required to maintain the PV array at its maximum power point, regulate the DC-link voltage, ensure sinusoidal grid currents with unity power factor, and impose a constant battery charging current. The three approaches are implemented under the same operating conditions and examined for irradiance variations. Their tracking and regulation performances are compared using numerical simulations developed in MATLAB/Simscape.