blockTransferFunction
Discrete Transfer Function block
Extends from Interfaces.DiscreteSISO (Single Input Single Output discrete control block).
Information
The discrete transfer function block defines the transfer function between the input signal u and the output signal y. The numerator has the order nb-1, the denominator has the order na-1.
b(1)*z^(nb-1) + b(2)*z^(nb-2) + ... + b(nb)
y(z) = -------------------------------------------- * u(z)
a(1)*z^(na-1) + a(2)*z^(na-2) + ... + a(na)
State variables x are defined according to controller canonical form. Initial values of the states can be set as start values of x.
Example:
Blocks.Discrete.TransferFunction g(b = {2,4}, a = {1,3});
results in the following transfer function:
2*z + 4
y = --------- * u
z + 3
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Real[:] | b | {1} | Numerator coefficients of transfer function. |
| Real[:] | a | {1} | Denominator coefficients of transfer function. |
| SI.Time | samplePeriod (from DiscreteBlock) | Sample period of component | |
| SI.Time | startTime (from DiscreteBlock) | 0 | First sample time instant |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Blocks.Interfaces.RealInput | u (from DiscreteSISO) | Connector of Real input signal | |
| Modelica.Blocks.Interfaces.RealOutput | y (from DiscreteSISO) | Connector of Real output signal |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Real[size(a, 1) - 1] | x | State of transfer function from controller canonical form |
Revisions
Release Notes:
- November 15, 2000
by Hans Olsson:
Converted to when-semantics of Modelica 1.4 with special care to avoid unnecessary algebraic loops. - June 18, 2000
by Martin Otter:
Realized based on a corresponding model of Dieter Moormann and Hilding Elmqvist.