Improved Feedback Control and Optimal Management for Battery Storage System in Microgrid Operating in Bi-Directional Grid Power Transfer

This paper presents an improved feedback controller and optimal management system to operate a battery storage system in a microgrid. The aim is to optimize the storage usage by reducing the battery degradation. The feedback controller regulates the battery current to track a reference despite uncertainties. It includes a disturbance observer to compensate unknown uncertainties and improve its tracking performance. The current reference is carried out using a management system based on the power balance in the microgrid connected to the main grid. Furthermore, the management system uses a coefficient to operate the battery depending on its constraints and the grid electricity price. This allows online optimization of the battery operation based on the price variations to reduce its degradation. The control and management systems are validated by simulation and the results are provided to demonstrate their effectiveness. Furthermore, experimentation is conducted to evaluate the control performance. The results show that the proposed feedback controller and disturbance observer provide better mean absolute error (0.0846) for the current tracking compared to only feedback controller (0.2073) and conventional proportional-integral controller (0.1126). Moreover, the proposed management system represents a reduction in the battery degradation by 74.56% compared to the conventional management system.