Numerical Simulation on Pressure Dynamic Response Characteristics of Hydrogen Systems for Fuel Cell Vehicles

A proton exchange membrane fuel cell (PEMFC) is known as one of the most promising energy sources for electric vehicles. A hydrogen system is required to provide hydrogen to the stack in time to meet the flow and pressure requirements according to the power requirements. In this study, a 1-D model of a hydrogen system, including the fuel cell stack, was established. Two modes, one with and one without a proportion integration differentiation (PID) control strategy, were applied to analyze the pressure characteristics and performance of the PEMFC. The results showed that the established model could be well verified with experimental data. The anode pressure fluctuation with a PID control strategy was more stable, which reduced the damage to the fuel cell stack caused by sudden changes of anode pressure. In addition, the performance of the stack with the PID control mode was slightly improved. There was an inflection point for hydrogen utilization; the hydrogen utilization rate was higher under the mode without PID control when the current density was greater than 0.4 A/cm2. What is more, a hierarchical control strategy was proposed, which made the pressure difference between the anode and cathode meet the stack working requirements, and, more importantly, maintained the high hydrogen utilization of the hydrogen system.