Active Disturbance Rejection Control for a Hybrid Energy Storage based Low Voltage DC Microgrid

Hybrid energy storage systems (HESS) that include batteries and supercapacitors are now widely used in DC microgrids to manage energy fluctuations. In this paper, a controller for voltage regulation in a photovoltaic DC microgrid with HESS is proposed. The controller's inner current loop is based on a proportional integral controller, while the outer voltage loop is based on Active Disturbance Rejection Control (ADRC). The overall current reference for storage systems is generated by the ADRC voltage controller and thereafter distributed to every storage device via a low-pass filter. The anticipated DC bus voltage and total disturbances are estimated using a linear Extended State Observer (ESO). When fast change loads are connected, the ADRC employs a double filter technique to even out battery charging and discharging. The proposed controller's effectiveness and response speed have been validated through simulations using MATLAB/ SIMULINK, and the results are compared to those of a traditional cascaded PI controller. The findings with the proposed controller based on time domain specifications like overshoot and setting time with value 0.13V and 20ms respectively which indicate that the new controller outperforms the conventional one in terms of disturbance resistance and dynamic performance.