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PS Transfer Function

Model low-pass and lead-lag filters

  • Library:
  • Simscape / Foundation Library / Physical Signals / Linear Operators

  • PS Transfer Function block

Description

The PS Transfer Function block lets you model first-order low-pass filters or lead-lag filters. Modeling both the plant and controller in a Simscape™ network improves simulation efficiency. The PS Transfer Function block lets you easily parameterize a filter in the desired configuration:

  • Lag — Model a first-order low-pass filter. You have to provide the lag time constant and the initial output as block parameters.

  • Lead-lag — Model a lead-lag filter. You have to provide the lead time constant, the lag time constant, and the initial output as block parameters.

The block icon changes depending on the value of the Transfer function type parameter.

Restriction TypeBlock Icon

Lag

Lead-lag

Untyped physical ports facilitate unit propagation. The output signal has the same physical unit as the input signal.

Assumptions and Limitations

  • The block assumes unity low-frequency gain. To model non-unity gain, connect a PS Gain block in series with the PS Transfer Function block.

Ports

Input

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Input physical signal.

The port name is not visible in the block icon, but you can see this name in the underlying source file (accessible by clicking the Source code link in the block dialog box).

Output

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Output physical signal.

The port name is not visible in the block icon, but you can see this name in the underlying source file (accessible by clicking the Source code link in the block dialog box).

Parameters

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Select the type of the low-pass filter:

  • Lag — Model a first-order low-pass filter.

  • Lead-lag — Model a lead-lag filter.

The lag time constant for first-order low-pass filter.

Dependencies

Enabled when the Transfer function type parameter is set to Lag.

The lead time constant for lead-lag filter.

Dependencies

Enabled when the Transfer function type parameter is set to Lead-lag.

The lag time constant for lead-lag filter.

Dependencies

Enabled when the Transfer function type parameter is set to Lead-lag.

The output signal value and unit at the beginning of a simulation run. The first edit box represents the signal value. This value can be a scalar, vector, or matrix, matching the size of the output signal at port Y.

The second combo box represents the signal unit, which must be commensurate with the unit of the output signal at port Y. By default, the unit is 1 (unitless). You can select a unit from the drop-down list or type the desired unit name, such as rpm, or a valid expression, such as rad/s. For more information and a list of unit abbreviations, see How to Specify Units in Block Dialogs and Unit Definitions.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

Introduced in R2020a