Analysis and feedback control of planar SOFC systems for fast load following in APU applications

Solid Oxide Fuel Cell (SOFC) based Auxiliary Power Unit (APU) systems have many practical advantages given their high efficiency, low emissions and flexible fueling strategies. This paper focuses on model-based analysis and feedback control design for planar SOFC systems to achieve fast load following capability. A dynamic model is first developed for the integrated co-flow planar SOFC and CPOX (Catalytic Partial Oxidation) system aiming at APU applications. Simulation results illustrate that an open-loop system with optimal steady-state operating setpoints exhibits a slow transient power response when load increases. Feedback control is then explored to speed up the system response by controlling the flow rates of fuel and air supplies to the system. Model linearization, balanced truncation and Linear Quadratic Gaussian (LQG) approaches are used to derive the low-order observer-based controller. With the feedback controller developed, we show, through simulations, that the closed-loop system can have faster load following capability. Different feedback strategies are also considered and their impacts on closed-loop system performance are analyzed.Copyright © 2006 by ASME

[1]  John A. MacBain,et al.  Logistics and Capability Implications of a Bradley Fighting Vehicle with a Fuel Cell Auxiliary Power Unit , 2004 .

[2]  Michel Cassir,et al.  Prospects of different fuel cell technologies for vehicle applications , 2002 .

[3]  S. Cocchi,et al.  A global thermo-electrochemical model for SOFC systems design and engineering , 2003 .

[4]  Jing Sun,et al.  Dynamic Model of Planar Solid Oxide Fuel Cells for Both Steady State and Transient Performance Analysis , 2005 .

[5]  E. Achenbach.  Three-dimensional and time-dependent simulation of a planar solid oxide fuel cell stack , 1994 .

[6]  Daniel Sperling,et al.  Evaluation of Fuel Cell Auxiliary Power Units for Heavy-Duty Diesel Trucks , 2002 .

[7]  J. Doyle,et al.  Essentials of Robust Control , 1997 .

[8]  Nigel P. Brandon,et al.  Anode-supported intermediate-temperature direct internal reforming solid oxide fuel cell. II. Model-based dynamic performance and control , 2005 .

[9]  C. Adjiman,et al.  Anode-supported intermediate temperature direct internal reforming solid oxide fuel cell. I: model-based steady-state performance , 2004 .

[10]  Jing Sun,et al.  Comparison of Dynamic Planar SOFC Models With Different Assumptions of Temperature Layers in Energy Balance , 2006 .

[11]  James Larminie,et al.  Fuel Cell Systems Explained , 2000 .

[12]  Fabian Mueller,et al.  Dynamic Simulation of an Integrated Solid Oxide Fuel Cell System Including Current-Based Fuel Flow Control , 2005 .

[13]  James Larminie,et al.  Fuel Cell Systems Explained: Larminie/Fuel Cell Systems Explained , 2003 .

[14]  Anna G. Stefanopoulou,et al.  Control of Fuel Cell Power Systems , 2004 .