Hierarchical Management Control Based on Equivalent Fitting Circle and Equivalent Energy Consumption Method for Multiple Fuel Cells Hybrid Power System

In order to reduce the operating cost of hydrogen fuel cell hybrid electric tram, this paper proposes a hierarchical control method, which includes a control layer and a management layer. In the control layer, through three-dimensional efficiency, modeling, and geometric solution of fuel cell system (FCS), the equivalent fitting circle method is adopted to realize the optimal allocation among sets of multiple fuel cells with different parameters. Meanwhile, in management layer, according to the operation states of tram, the supercapacitor dynamic energy consumption coefficient is proposed and applies in the tram efficiency model for the equivalent energy consumption (EEC) method, and the improved EEC method can accurately provide the optimal power distribution of the hybrid system under different operating conditions. According to RT-LAB platform tests, compared with other online methods under the same operating conditions, the proposed method has the apparent satisfactory results in reducing hydrogen consumption. What is more, the actual tram operation test also shows that the proposed method ensures the output stability of the FCS so as to prolong its life and reduce its operation and maintenance costs.