Non-linear model predictive control applied to PEM Fuel Cells: Anode pressure and humidity regulation
Tutor / director / evaluatorOcampo-Martínez, Carlos
Document typeMaster thesis
Rights accessOpen Access
In this thesis, a nonlinear model predictive control (NMPC) strategy is proposed to regulate the humidity and pressure in a Proton Exchange Membrane Fuel Cell (PEMFC) anode. The proposed control strategy uses two controllers in cascade to control the humidity and pressure in the anode, separately. This approach is used in order to overcome the difficulties caused by two dynamics with time-constants orders of magnitude apart. The inner loop, with the fastest dynamics, regulates the pressure in the anode with the set-point provided by the outer loop. The outer loop regulates the relative humidity in the anode using the temperature in the anode humidifier and also the reference pressure in the anode. The controllers developed in this thesis are based on the explicit non-linear equations describing the mass balances in the fuel cell. With this strategy, safety and performance constraints for pressure and humidity can be guaranteed and external disturbances, as changes in stack current demand, are rejected. Simulation results are presented to show the capabilities of the proposed controller under different settings and control laws. The results obtained show satisfactory regulation of the humidity and pressure with promising performance regulating the humidity with the pressure constrained to a single value. The approach followed can be used to extend this design to the anode and cathode of similar PEMFC systems with similar characteristics.