State-of-health-coupled power sharing in a hierarchical control framework for battery-supercapacitor hybrid energy storage in solar-powered microgrids

Abstract

Battery-supercapacitor hybrid energy storage systems (HESSs) are widely used in PV-based DC microgrids to compensate renewable intermittency and support DC-bus voltage regulation. However, many existing power-sharing strategies do not directly account for the evolving health condition of the storage devices, exposing aging batteries to excessive transient current stress. To address this limitation, this paper proposes a hierarchical control framework based on state-of-health-coupled dynamic impedance shaping. The outer layer employs linear active disturbance rejection control (LADRC) for DC-bus regulation; the supervisory layer adapts the virtual impedances of the battery and supercapacitor according to health, state of charge, and transient severity; and the inner layer uses integral sliding-mode control (ISMC) for robust branch-current tracking. In this way, the proposed method establishes a direct health-to-control link for real-time degradation-aware power routing. Comparative simulations and real-time digital validation on a dSPACE MicroLabBox 1202 platform confirm that the proposed controller substantially reduces battery current stress while preserving DC-bus regulation. In the MicroLabBox-based real-time tests, relative to the LADRC-ISMC benchmark, the proposed LADRC-SoH-ISMC reduces the battery RMS current by 76.8% and the battery peak current by 73.0%, while maintaining the DC-bus RMS voltage error below 0.1 V. The results demonstrate that SoH-coupled impedance shaping can protect the battery without imposing uncontrolled supercapacitor stress, thereby improving the lifetime-performance tradeoff of PV-based HESS operation.