Decentralized Active Disturbance Rejection Control for Hybrid Energy Storage System in DC Microgrid

Nowadays, hybrid energy storage system (HESS) is a popular option to compensate for renewable energy fluctuations in the microgrid. The main advantages of HESS are that it can eliminate bus voltage fluctuations and maximize the strength of multifarious energy storage systems with different characteristics. Therefore, power allocation between different ESSs is a major issue for HESS. Moreover, the high integration of constant power loads brings instability issues to the dc microgrid. To address the above concerns, this article proposes a decentralized power sharing and stabilization method based on active disturbance rejection control (ADRC). First, an ADRC controller is proposed for a single ESS, where the system disturbance is estimated and compensated through an extended state observer (ESO). Thus, the dc-bus voltage is maintained. Second, an ADRC-based decentralized method for HESS is developed. ESO can estimate the output current of converters. Thus, the current sensors of the local controller can be reduced. Furthermore, the proposed method is extended into HESS with multiple batteries and SCs, which verifies its scalability. Stability analysis is performed to guarantee the large-signal stability of the whole system. At last, simulation and experimental have been conducted to verify the feasibility of the proposed method.