Control strategy plays a significant role in ensuring system stability and performance as well as equipment protection for maximum service life. This work is aimed at investigating the control strategies for start-up and part-load operating conditions of the solid oxide fuel cell/gas turbine (SOFC/GT) hybrid system. First, a dynamic SOFC/GT hybrid cycle, based on the thermodynamic modeling of system components, has been successfully developed and simulated in the virtual test bed simulation environment. The one-dimensional tubular SOFC model is based on the electrochemical and thermal modeling, accounting for voltage losses and temperature dynamics. The single cell is discretized using a finite volume method where all the governing equations are solved for each finite volume. Two operating conditions, start-up and part load, are employed to investigate the control strategies of the SOFC/GT hybrid cycle. In particular, start-up control is adopted to ensure the initial rotation speed of a compressor and a turbine for a system-level operation. The control objective for the part-load operation regardless of load changes, as proposed, is to maintain constant fuel utilization and a fairly constant SOFC temperature within a small range by manipulating the fuel mass flow and air mass flow. To this end, the dynamic electrical characteristics such as cell voltage, current density, and temperature under the part load are simulated and analyzed. Several feedback control cycles are designed from the dynamic responses of electrical characteristics. Control cycles combined with control related variables are introduced and discussed.

1.
Selimovic
,
A.
, and
Palsson
,
J.
, 2002, “
Networked Solid Oxide Fuel Cell Stacks Combined With a Gas Turbine Cycle
,”
J. Power Sources
,
4663
, pp.
1
7
. 0378-7753
2.
Hirschenhofer
,
J. H.
,
Stauffer
,
D. B.
,
Engleman
,
R. R.
, and
Klett
,
M. G.
., 1998,
Fuel Cell Handbook
,
4th ed.
,
Parsons Corporation
,
Reading, PA
.
3.
Chan
,
S. H.
,
Ho
,
H. K.
, and
Tian
,
Y.
, 2003, “
Modeling for Part-Load Operation of Solid Oxide Fuel Cell-Gas Turbine Hybrid Power Plant
,”
J. Power Sources
0378-7753,
114
, pp.
213
227
.
4.
Campanari
,
S.
, 2000, “
Full Load and Part Load Performance Prediction for Integrated SOFC and Microturbine Systems
,”
ASME J. Eng. Gas Turbines Power
0742-4795,
122
, pp.
239
246
.
5.
Pålsson
,
J.
, and
Selimovic
,
A.
, “
Design and Off-Design Predictions of a Combined SOFC and Gas Turbine System
,” ASME Paper No. 2001-GT-0379.
6.
Kimijima
,
S.
, and
Kasagi
,
N.
, “
Performance Evaluation of Gas Turbine-Fuel Cell Hybrid Micro Generation System
,” ASME Paper No. 2002-GT-30111.
7.
Stiller
,
C.
,
Thorud
,
B.
,
Bolland
,
O.
,
Kandepu
,
R.
, and
Imsland
,
L.
, 2006, “
Control Strategy for a Solid Oxide Fuel Cell and Gas Turbine Hybrid System
,”
J. Power Sources
,
158
, pp.
303
315
. 0378-7753
8.
Thorud
,
B.
,
Bolland
,
O.
, and
Kvamsdal
,
H.
, 2002, “
Modelling and Simulation of Transient Behaviour of SOFC
,”
Proceedings of the Symposium on Polymer Fuel Cells
, Throndheim, Norway.
9.
Aguiar
,
P.
,
Adjiman
,
C.
, and
Brandon
,
N.
, 2005, “
Anode-Supported Intermediate Temperature Direct Internal Reforming Solid Oxide Fuel Cell, II: Model-Based Dynamic Performance and Control
,”
J. Power Sources
0378-7753,
147
, pp.
136
147
.
10.
Cokkinides
,
G.
, and
Beker
,
B.
, VTB Model Developer’s Guide, available at http://vtb.engr.sc.edu/modellibrary/modeldev.asphttp://vtb.engr.sc.edu/modellibrary/modeldev.asp
11.
Cokkinides
,
G.
, and
Beker
,
B.
, 1998, RC and AC Models in the VTB Time Domain Solver, The VTB Documentation, Dec. 4.
12.
Jiang
,
W.
,
Khan
J.
, and
Dougal
,
R. A.
, 2006, “
Dynamic Centrifugal Compressor Model for System Simulation
,”
J. Power Sources
0378-7753,
158
(
2
), pp.
1333
1343
.
13.
Jiang
,
W.
,
Fang
,
R.
,
Dougal
,
R. A.
, and
Khan
J.
, 2006, “
Parameter Setting and Analysis of a Dynamic Tubular SOFC Model
,”
J. Power Sources
0378-7753,
162
(
1
), pp.
316
326
.
14.
Achenbach
,
E.
, 1994, “
Three Dimensional and Time Dependent Simulation of a Planar Solid Oxide Fuel Cell Stack
,”
J. Power Sources
0378-7753,
49
, pp.
333
348
.
15.
Sedghisigarchi
,
K.
, 2004, “
Dynamic and Transient Analysis of Power Distribution Systems With Fuel Cells, Part I: Fuel-Cell Dynamic Model
,”
IEEE Trans. Energy Convers.
,
19
, pp.
429
434
.
16.
Bossel
,
U. G.
, 1992, “
Final Report on SOFC Data Facts and Figures
,” Swiss Federal Office of Energy, Berne, CH.
17.
Reid
,
R. C.
,
Prausnitz
,
J. M.
, and
Poling
,
B. E.
, 1987,
The Properties of Gases and Liquids
,
McGraw-Hill
,
New York
.
18.
Hall
,
D. J.
, and
Colclaser
,
R. G.
, 1999, “
Transient Modeling and Simulation of Tubular Solid Oxide Fuel Cells
,”
IEEE Trans. Energy Convers.
0885-8969,
14
, pp.
749
753
.
19.
Bessette
,
N. F.
, 1994, “
Modeling and Simulation for Solid Oxide Fuel Cell Power Systems
,” Ph.D. thesis, Georgia Institute of Technology, Atlanta, GA.
20.
Rokni
,
M.
, and
Yuan
,
J.
, 1994, “
The Development of Heat Transfer and Gas Flow Modeling in the Solid Oxide Fuel Cells (SOFC)
,”
Proceedings of the Electrochemical Society
, SOFC-VI, Honululu, HI, October.
21.
Jiang
,
W.
, “
Models Development and Dynamic Simulation of SOFC-Gas Turbine Hybrid System
,” Ph.D. thesis, University of South Carolina, Columbia, SC.
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