Control Strategy for Bus Voltage in a Wind–Solar DC Microgrid Incorporating Energy Storage

Aiming at the DC bus voltage instability problem resulting from the stochastic nature of distributed energy output and load fluctuation, an Integral Sliding Mode Linear Active Disturbance Rejection Control (ISMLADRC) combined with Model Predictive Control (MPC) strategy for energy storage bi-directional DC–DC converter is proposed based on the wind–solar-storage DC microgrid system. The proposed method utilizes a dual closed-loop control structure, employing a two-step MPC approach in the inner current loop to enhance the system’s dynamic response performance. Secondly, the integral sliding mode control algorithm is embedded into the Linear Active Disturbance Rejection (LADRC) technique, based on which the outer voltage loop ISMLADRC controller is designed to mitigate the impact of disturbances on the bus voltage effectively, and the system’s anti-disturbance performance and robustness are improved. Considering that the parameters of the ISMLADRC controller are too many to be tuned, and in order to give full play to the performance of the controller, an Improved Dung Beetle Optimization Algorithm (IDBO) is used to tune the parameters. Finally, based on MATLAB 2022b and RT-LAB 2021.3 platforms, the simulation results show that in a variety of operating conditions, the proposed control strategy can flexibly regulate the bidirectional transmission of battery energy, and the bus voltage recovery time is within 0.1 s, and the voltage fluctuation is less than 0.5%.