This paper presents the study of the effect variations in the heat effluence from a solid oxide fuel cell (SOFC) has on a gas turbine hybrid configuration. The SOFC is simulated through hardware at the U.S. Department of Energy, National Energy Technology Laboratory (NETL). The gas turbine, compressor, recuperative heat exchanger, and other balance of plant components are represented by actual hardware in the Hybrid Performance Test Facility at NETL. Fuel cell heat exhaust is represented by a combustor that is activated by a fuel cell model that computes energy release for various sensed system states System structure is derived by means of frequency response data generated by the sinusoidal oscillation of the combustor fuel valve over a range of frequencies covering three orders of magnitude. System delay and order are obtained from Bode plots of the magnitude and phase relationships between input and output parameters. Transfer functions for mass flow, temperature, pressure, and other states of interest are derived as a function of fuel valve flow, representative of fuel cell thermal effluent. The Bode plots can validate existing analytical transfer functions, provide steady state error detection, give a stability margin criterion for the fuel valve input, estimate system bandwidth, identify any nonminimum phase system behavior, pinpoint unstable frequencies, and serve as an element of a piecewise transfer function in the development of an overall transfer function matrix covering all system inputs and outputs of interest. Further loop shaping techniques and state space representation can be applied to this matrix in a multivariate control algorithm.

1.
Tucker
,
D.
,
Smith
,
T.
, and
Lawson
,
L.
, 2006, “
Characterization of Bypass Control Methods in a Coal-Based Fuel Cell Turbine Hybrid
,”
Proceedings of ICEPAG2006 International Colloquium on Environmentally Preferred Advanced Power Generation
, Newport Beach, CA, Sept. 5–8,
ASME
,
New York
.
2.
Tucker
,
D.
,
Lawson
,
L.
, and
Gemmen
,
R.
, 2005, “
Characterization of Air Flow Management and Control in a Fuel Cell Turbine Hybrid Power System Using Hardware Simulation
,” ASME Paper No. PWR2005-50127.
3.
Shelton
,
M.
,
Tucker
,
D.
,
Liese
,
E.
,
Celik
,
I.
, and
Lawson
,
L.
, 2005, “
A Transient Model of a Hybrid Fuel Cell/Gas Turbine Test Facility Using Simulink
,” ASME Paper No. GT2005-68467.
4.
Smith
,
T.
,
Liese
,
E.
,
Haynes
,
C.
, and
Gemmen
,
R.
, 2006, “
A Dynamic Bulk SOFC Model Used in a Hybrid Turbine Controls Test Facility
,” ASME Paper No. GT2006-90383.
5.
Ferrari
,
M.
,
Traverso
,
A.
,
Magistri
,
L.
, and
Massardo
,
A.
, 2005, “
Control System for Solid Oxide Fuel Cell Hybrid Systems
,” ASME Paper No. GT2005-68102.
6.
Morgans
,
A.
, and
Dowling
,
A.
, 2005, “
Model Based Control of Combustion Instabilities
,” ASME Paper No. GT2005-68897.
7.
Katsuhiko
,
O.
, 2002,
Modern Control Engineering
,
4th ed.
,
Prentice-Hall
,
Englewood Cliffs, NJ
.
8.
Eronini
,
U. -E.
, 1999,
System Dynamics and Control
,
PWS
,
Pacific Grove, CA
.
9.
Torkel
,
G.
, and
Ljung
,
L.
, 2000,
Control Theory, Multivariable and Nonlinear Methods
,
Taylor & Francis
,
London
.
10.
Skogestad
,
S.
, and
Postlethwaite
,
I.
, 2005,
Multivariable Feedback Control, Analysis and Design
,
2nd ed.
,
Wiley
,
New York
.
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