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- Specifying the Absolute Tolerance for the Block's States
By default Simulink uses the absolute tolerance value specified in the Configuration Parameters dialog box (see Absolute tolerance) to solve the states of the Transfer Fcn block. If this value does not provide sufficient error control, specify a more appropriate value in the Absolute tolerance field of the Transfer Fcn block's dialog box. The value that you specify is used to solve all the block's states.
The Transfer Fcn block accepts and outputs signals of type double.
- Parameters and Dialog Box
The row vector of numerator coefficients. A matrix with multiple rows can be specified to generate multiple output. The default is [1].
The row vector of denominator coefficients. The default is [1 1].
Absolute tolerance used to solve the block's states. You can enter auto or a numeric value. If you enter auto, Simulink determines the absolute tolerance (see Specifying Variable-Step Solver Error Tolerances). If you enter a numeric value, Simulink uses the specified value to solve the block's states. Note that a numeric value overrides the setting for the absolute tolerance in the Configuration Parameters dialog box
Characteristics
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The Transfer Fcn block models a linear system by a transfer function of the Laplace-domain variable s. The block can model both single-input single-output (SISO) and single-input multiple output (SIMO) systems.
This block assumes that the transfer function has the following form:
Where u and y are the system's input and outputs, respectively, nn and nd are the number of numerator and denominator coefficients, respectively. num and den contain the coefficients of the numerator and denominator in descending powers of s. The order of the denominator must be greater than or equal to the order of the numerator. This block also assumes that the transfer functions for the outputs of a multiple output system have the same denominator and that the numerators of the transfer functions have the same order.
To model a single-output system, enter a vector containing the system transfer function's numeric coefficients in the Numerator coefficient field in the block's parameter dialog box. Enter a vector containing the transfer function's denominator coefficients in the Denominator coefficient field. In this case, the input and output of the block are scalar time-domain signals.
To model a multiple-output system, enter a matrix in the Numerator coefficient field where each row of the matrix contains the numerator coefficients of a transfer function that determines one of the block's outputs. Enter a vector containing the denominator coefficients common to the system's transfer functions in the Denominator coefficient field. In this case, the block's input is a scalar and the block's output is a vector each of whose elements is an output of the system modeled by the block.
Initial conditions are preset to zero. If you need to specify initial conditions, convert to state-space form using tf2ss and use the State-Space block. The tf2ss utility provides the A, B, C, and D matrices for the system.
The numerator and denominator are displayed on the Transfer Fcn block depending on how they are specified:
- If each is specified as an expression, a vector, or a variable enclosed in parentheses, the icon shows the transfer function with the specified coefficients and powers of s. If you specify a variable in parentheses, the variable is evaluated. For example, if you specify Numerator as [3,2,1] and Denominator as (den) where den is [7,5,3,1], the block looks like this:
- If each is specified as a variable, the block shows the variable name followed by (s). For example, if you specify Numerator as num and Denominator as den, the block looks like this
Electric machines play an important role in industry as well as our day to day life. They are used to generate electrical power in power plants and provide mechanical work in industries. They are also an indispensable part of our daily lives. Electric machines are very important pieces of equipment in our everyday lives. The DC machine is considered to be basic electric machines.
The aim of this final year project is to introduce students to the modeling of power components and to use computer simulation as a tool for conducting transient and control studies. Simulation can be very helpful in gaining insights to the dynamic behavior and interactions that are often not readily apparent from reading theory. Simulation is often chosen by engineers to study transient and control performance or to test conceptual designs.
MATLAB/SIMULINK is used because of the short learning curve that most students require to start using it, its wide distribution, and its general purpose of nature. This will demonstrate the advantages of using MATLAB for analyzing power system steady-state behavior and its capabilities for simulating transients in power systems and power electronics, including control system dynamic behavior
