A Decentralized Dynamic Load Power Allocation Strategy for Fuel Cell/Supercapacitor-Based APU of Large More Electric Vehicles

In this paper, an enhanced mixed droop control strategy is proposed for a fuel cell/supercapacitor-based auxiliary power unit (FC/SC-APU), which is usually used in large electric vehicles, to achieve the dynamic load power allocation in a decentralized way. By applying an adjustable virtual impedance droop scheme to the SC converter and a virtual resistor droop scheme to the FC converter, the SC is able to buffer the fast-changing or pulsating load power flow, leaving the FC only providing the average load power. Since this method is fully decentralized, it features high flexibility and scalability. Furthermore, the proposed strategy is very suitable for extending the system's service life because the recovery and operational limit of the state-of-charge of SC have been considered in the power allocation. The operational principle of the proposed control strategy and the system design are elaborated, followed by which real-time simulations are conducted to verify theoretical analyses.