Input–Output Models : The Transfer Function

2016 ◽  
pp. 112-133
Keyword(s):  
Transfer Function ◽  
Input Output

The uniqueness of the transfer function of linear systems from input-output observations

Metrika ◽  
1984 ◽  
Vol 31 (1) ◽  
pp. 157-181
Author(s):  
M. Deistler ◽  
B. M. Pötscher ◽  
J. Schrader
Keyword(s):  
Transfer Function ◽  
Linear Systems ◽  
Input Output

RGA Analysis of a Solid Oxide Fuel Cell Gas Turbine Hybrid Plant

2008 ◽  
Author(s):  
Alex Tsai ◽  
Larry Banta ◽  
David Tucker ◽  
Randall Gemmen
Keyword(s):  
Transfer Function ◽  
Gas Turbine ◽  
Hybrid Plant ◽  
Test Facility ◽  
Input Output ◽  
Test Bed ◽  
Response Data ◽  
Output System ◽  
Hybrid Configuration ◽  
System Coupling

This paper presents a Relative Gain Array (RGA) analysis of a simulated SOFC/Gas Turbine plant based on a multivariate empirical formulation of a 300kW hybrid system. The HyPer test facility at the National Energy Technology Laboratory, served as the test bed for deriving frequency response data and subsequent multivariable model of a direct fired, recuperated hybrid cycle plant. Through the modulation of various airflow bypass-valves, magnitude and phase data is used to formulate Transfer Function {TF} equations that describe input/output system interaction. A frequency dependent RGA calculation of the empirical Transfer Function matrix provides a means of quantifying the degree of coupling between system inputs and outputs for the configuration studied. Various input/output interaction time scales are obtained to identify frequencies where fully developed system coupling occur. Analysis of the RGA matrix leads to a better understanding of the inherent properties the hybrid configuration, and can serve as a validating tool to existing analytical RGA calculations of similar types of hybrids.

scholarly journals Multidimensional Wave Field Signal Theory: Transfer Function Relationships

2012 ◽  
Vol 2012 ◽  
pp. 1-27 ◽  
Author(s):  
Natalie Baddour
Keyword(s):  
Transfer Function ◽  
Signal Theory ◽  
Fourier Domain ◽  
Theoretic Approach ◽  
Input Output ◽  
Coordinate Systems ◽  
Fourier Inversion ◽  
Inversion Formulas ◽  
Transmission Of Information ◽  
Physical Phenomena

The transmission of information by propagating or diffusive waves is common to many fields of engineering and physics. Such physical phenomena are governed by a Helmholtz (real wavenumber) or pseudo-Helmholtz (complex wavenumber) equation. Since these equations are linear, it would be useful to be able to use tools from signal theory in solving related problems. The aim of this paper is to derive multidimensional input/output transfer function relationships in the spatial domain for these equations in order to permit such a signal theoretic approach to problem solving. This paper presents such transfer function relationships for the spatial (not Fourier) domain within appropriate coordinate systems. It is shown that the relationships assume particularly simple and computationally useful forms once the appropriate curvilinear version of a multidimensional spatial Fourier transform is used. These results are shown for both real and complex wavenumbers. Fourier inversion of these formulas would have applications for tomographic problems in various modalities. In the case of real wavenumbers, these inversion formulas are presented in closed form, whereby an input can be calculated from a given or measured wavefield.

scholarly journals Modeling for Control of Rotating Stall in High Speed Multi-Stage Axial Compressors

1994 ◽  
Author(s):  
Matthew R. Feulner ◽  
Gavin J. Hendricks ◽  
James D. Paduano
Keyword(s):  
Transfer Function ◽  
Compressible Flow ◽  
Active Control ◽  
High Speed ◽  
Standard Form ◽  
Pressure Sensors ◽  
Rotating Stall ◽  
Input Output ◽  
Axial Compressors ◽  
Blade Row

Using a two dimensional compressible flow representation of axial compressor dynamics, a control-theoretic input-output model is derived which is of general utility in rotating stall/surge active control studies. The derivation presented here begins with a review of the fluid dynamic model, which is a 2D stage stacking technique that accounts for blade row pressure rise, loss and deviation as well as blade row and inter-blade row compressible flow. This model is extended to include the effects of the upstream and downstream geometry and boundary conditions, and then manipulated into a transfer function form that dynamically relates actuator motion to sensor measurements. Key relationships in this input-output form are then approximated using rational polynomials. Further manipulation yields an approximate model which is in standard form for studying active control of rotating stall and surge. As an example of high current relevance, the transfer function from an array of jet actuators to an array of static pressure sensors is derived. Numerical examples are also presented, including a demonstration of the importance of proper choice of sensor and actuator locations, as well as a comparison between sensor types. Under a variety of conditions, it was found that sensor locations near the front of the compressor or in the downstream gap are consistently the best choices, based on a quadratic optimization criterion and a specific 3-stage compressor model. The modeling and evaluation procedures presented here are a first step toward a rigorous approach to the design of active control systems for high speed axial compressors.

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