Modeling, control and analysis of a novel energy-saving oriented fuel cell anode system

Abstract

Fuel cell hydrogen supply sub-system needs to provide sufficient mass flow and pressure of hydrogen to meet the working demand of the stack. The hydrogen circulation pump is often used, but causes additional parasitic power of fuel cell system. In this study, a new structure of hydrogen circulation pump is proposed to reduce the parasitic power by using the pressure potential energy of hydrogen flow. The hydrogen feeding system model is established based on the solution of differential equation of state of ideal gas, mass and energy balance. Then, considering the hydrogen intake pressure and the hydrogen excess ratio of the system, a reasonable control strategy is proposed for accurate control. Simulation results show that under the fuel cell work condition and the fuel cell vehicle operation condition, pressure difference between anode and cathode and the hydrogen excess ratio can be regulated to the conditions required by the stack, and the excess ratio error and pressure difference error between anode and cathode is 3.82e-3 and 4.52e-4 Bar, respectively. The parasitic power consumption of the circulating pump is effectively reduced about two-thirds under the fuel cell vehicle operation condition. Then, the effects of anode hydrogen pressure drop, hydrogen inlet pressure and entrainment ratio of ejector on the system are studied. Reducing the anode pressure drop, increasing the ejector entrainment ratio while reducing the hydrogen inlet pressure at low power and increasing it at high power are conducive to energy-saving of the system.