Energy management and economic analysis for a fuel cell supercapacitor excavator

Abstract

Fuel cell hybrid excavators (FCHEs) are an attractive long-term future option. This paper presents an approach for the energy management and economic analysis for an excavator powered by fuel cell and supercapacitor. The operating conditions and energy flows of a hydraulic excavator are analysed, the influence factors of the fuel cell stack (FCS) lifetime under the operating conditions are discussed. The marked load changes posed major challenges to the FCS performance, appropriate energy management strategies (EMSs) for FCHEs are indispensable. Three representative EMSs based on dynamic programming, Pontryagin's minimum principle, and model predictive control are developed, considering hydrogen consumption and FCS durability. Simulations performed in the MATLAB environment with cyclic loading of an excavator demonstrate the superiority of the proposed EMSs. With the introduction of restrictions on FCS power change, FCS durability can be improved. Economic analysis of the FCHE is proposed, which includes the effect of FCS and supercapacitor sizes on hydrogen consumption, and the use-cost at the present and in the future. It indicates that the sizes of FCS are the primary influence on the FCHE fuel economy. FCHEs will become increasingly attractive as costs fall.