A Simplified Control Oriented Model Of an Open Cathode PEM Fuel Cell

Abstract

the paper presents a simplified nonlinear model for an open cathode Proton Exchange Membrane Fuel Cell (PEMFC) and its control using two different control strategies. The model presented uses only three state variables and is therefore easy to model and control. The mass flow of oxygen, hydrogen and water were taken to be the key dynamics in the system. The unknown parameters were estimated using the experimental data of a 1.2 kW PEMFC. The model showed good agreement with experimental results. With the objective of maintaining a fixed oxygen excess ratio – a Proportional Integral (PI) Control and a Sliding Mode Control (SMC) scheme were applied to the system model. This paper compares the results of a simple PEMFC model without controller, with a PI controller and a Sliding Mode controller. The SMC performs better in terms of maintaining a fixed oxygen excess ratio of 2. The results also show that the simplified model has good use at an early design stage for systems using PEMFC and also for learning purposes.