Sliding Mode Control for Power Tracking of Proton-Exchange Membrane Fuel-Cell System

This paper proposes a novel approach to control the output power of a proton-exchange membrane fuel-cell (PEMFC) system by the current rate of change. First, a 70-kW PEMFC system model is established, which is validated by the experimental data with the maximum error of the output voltage being 3.68%. Then, a multi-input multi-output (MIMO) sliding mode controller (SMC) is designed based on the PEMFC model to maintain the excess oxygen ratio, the pressure difference between the cathode and anode, the stack temperature, and the output power at expectations. Finally, the simulation results show that the designed MIMO SMC performs better than the conventional proportional integral (PI) controller. When the PEMFC system responds to the dynamically changing power demand, the maximum power tracking error is 4.79%, the temperature fluctuation is about 0.06 K, and the pressure difference is maintained within 10 Pa.