Decentralized Power Management Strategy of a Fuel Cell/Battery/Supercapacitor Hybrid Energy Storage System in Electric Propulsion Aircraft

The fuel cell(FC)/battery/supercapacitor(SC) hybrid energy storage system (HESS) is the most promising solution for electric propulsion aircraft (EPA) to realize the power balance, where system instability caused by the high penetration of constant power loads (CPLs) is also a critical concern. To achieve the decentralized automatic power sharing and accurate DC bus voltage regulation of the HESS, a decentralized power management strategy is proposed in this paper. First, the combination of virtual inductor/virtual resistor/virtual capacitor droops are designed for the HESS, FC/battery/SC respectively provides the low-frequency/medium-frequency/high-frequency parts of the load power. Meanwhile, with the proposed droop strategy, not only the DC voltage variation caused by the droop control can be avoided, the reliable dynamic and steady power sharing performance can be also guaranteed in the case of one ES is disconnected from the system. Second, taking the unstable characteristics of the DC bus configuration caused by CPLs into consideration, the v₀2-P₀ droop algorithm has been proposed for the HESS to extended the stable margin of the HESS feeding CPLs. Finally, simulation results verify the effectiveness and superiority of the proposed controller.