Multivariable Control of Fuel Cell Breathing in Ground Vehicle Propulsion

Regents Of The University Of Michigan - Ann Arbor, Ann Arbor MI

Investigators

Abstract

Over the last decade there have been dramatic improvements in proton exchange membrane (PEM) fuel cells that enabled fuel cell power to transcend from the laboratory to experimental vehicles. However, the viability, efficiency, and robustness of this technology depend on understanding, predicting, and controlling the unique transient behavior of the Fuel Cell (FC) breathing system. Although steady-state FC behavior is considered the normal operating mode; start-up, shut-down, and sudden load changes are characteristic and ubiquitous to all power producing devices. During all operating modes, our ability to precisely control the reactant flow and pressure, stack temperature, and membrane humidity is critical. To this end, phenomenological models and robust control methodologies are developed to address the subsystem conflicts and account for the nonlinear interactions and constraints imposed by sensor fidelity and actuator authority. Insight and rigorous metrics are provided for the vehicle power management and level of hybridization with battery and/or ultra-capacitor. Finally, the impact of the control architecture for the coordination of all the three electric power sources (FC, battery, ultra-capacitor) with the traction motor inverter is systematically analyzed. This project allows students to develop control theoretic tools for the highly interdisciplinary areas of FC vehicles and power systems. Both of these technologies are important to our national competitiveness and a sustainable environment.