Continuous Robust Control of Hybrid Energy Storage System with RED-based Extended State Observers

This study proposes a continuous robust control approach for Hybrid Energy Storage Systems (HESS) using Robust-Exact-Differentiators (RED)-based Extended State Observers (ESOs). Firstly, according to the charging and discharging characteristics of the supercapacitor and the battery, a low-pass filter is developed to distribute the fluctuating power. The battery handles the low-frequency component of the voltage loop output signal, and the supercapacitor manages the high-frequency component. Secondly, in the voltage outer loop, an adaptive active disturbance rejection controller is proposed to generate the reference current for the inner loop. Thirdly, in the current inner loop with battery and supercapacitor, two RED-based ESOs are utilized to reconstruct the unknown current derivative, and continuous robust controllers are designed by using the RED-based ESOs. Simulation results demonstrate the effectiveness of the proposed method for HESS with RED-based ESOs.