Disturbance Observer based Power Management Strategy for a Grid-Interactive Microgrid with Hybrid Energy Storage System

A Power Management Strategy (PMS) based on a disturbance observer is proposed for a solar-wind-battery-supercapacitor system integrated with the grid. The control scheme for the hybrid energy storage system comprising of battery and supercapacitor is designed using a Second Order Sliding Mode Controller (SOSMC) and a Modified Second Order Sliding Mode Observer (MSOSMO). The power management algorithm determines the mode of operation based on the estimated power value by the MSOSMO. The observer gives a fast estimation of disturbances and thereby the proposed scheme gives better DC bus voltage regulation. The effectiveness of the power management strategy is verified during charging, discharging, and grid-connected modes of operation for different SoCs of the battery and supercapacitor using MATLAB/Simulink.