A fuel cell system and method for determining the speed of a recirculation pump in an anode recirculation circuit of a fuel cell system

摘要

A method of determining the speed of a recirculation pump (30) in an anode recirculation loop of a fuel cell stack (12) based on a predetermined ratio of fresh hydrogen to recirculated hydrogen, the method comprising: measuring the pressure drop across the recirculation pump (30); fresh hydrogen is fed into the recirculation cycle; measuring the temperature of the anode recycle gas flowing through the recirculation loop, mixed with the fresh hydrogen and supplied to the anode side of the fuel cell stack (12); calculating the pressure drop across the anode side of the fuel cell stack (12); the volume flow of the recirculation gas through the anode side of the fuel cell stack (12) is calculated as a function of the calculated pressure drop across the anode side of the fuel cell stack (12), the percentage of hydrogen in the recirculation gas, the measured temperature and the measured pressure drop across the recirculation pump (30) ; and the calculated volume flow and the amount of fresh hydrogen supplied to the recirculation loop are used to determine the speed of the recirculation pump (30) to reach the predetermined ratio, wherein calculating the pressure drop across the anode side of the fuel cell stack ( 12) that the equation is used: ΔpAnode (1 -Verubline) · (ΔpPump-ΔpAbscheider) where ΔpAnode is the pressure drop across the anode side of the fuel cell stack (12), the tubing is a constant value corresponding to the pressure drop across a tubing in the Is associated with the recirculation circuit, Δp pump is the measured pressure drop across the recirculation pump (30), and Δp separator is the pressure drop across a water separator (26) located in the recirculation circuit and removing water from the recirculation gas.