Stability Enhancement of Turboelectric Hybrid Power System With Decentralized Energy Management Strategy

Abstract

Turboelectric hybrid power architecture, including a generator driven by a gas turbine and energy storage system (ESS), is considered one of the attractive topologies for meeting the power demands of distributed electric propulsion (DEP). To achieve autonomous decentralized power sharing and stable dc bus voltage regulation of the turbogenerator (TG) and ESS hybrid power supply system (HPSS), a novel control strategy that combines virtual impedance droop (VID) with load-side series virtual moment of inertia (LSVI) is proposed in this article. First, the VID control strategy is designed to allow the TG to provide the low-frequency portion of the load fluctuations, while the ESS buffers the high-frequency fluctuations. Second, as an electromechanically coupled system, it suffers from the instability caused by the mismatch between the gas turbine’s mechanical characteristics and the load’s electrical characteristics. The proposed LSVI is introduced to reshape the load-side input mechanical impedance, which prevents inducing and propagation of gas turbine self-oscillations and further improves the stability. The operational principle of the proposed control strategy and the system design are elaborated. Finally, a 3.5-kW hybrid-electric experiment setup is fabricated to verify the feasibility and effectiveness of the theoretical analysis.