Simulation and Analysis of Fuel Cell Air Supply System in Variable Altitude Environment

The efficiency of the fuel cell and dynamics of the air supply system are significantly affected by altitude changes. To comprehensively investigate the influences of oxygen excess ratio (OER) and inlet pressure on output performance at different altitude, a variable altitude model that includes air compressor mechanism modeling is proposed. Experimental verification shows that the error of the compressor model within 5% at different altitude, the error of the voltage of the variable altitude model within 1.5% and the error of the air supply pressure within 1% in different altitude environments. The analysis of the impact of altitude and air supply parameters indicates that the optimal oxygen excess ratio tends to decrease with increasing altitude due to the saturation effect of the flow rate on performance enhancement, while the optimal air pressure needs to consider the balance between stack and auxiliary system.