Estimate Frequency Response Using Model Linearizer

This example shows how to estimate the frequency response of a portion of a Simulink^®model using theModel Linearizer. To estimate the frequency response, you specify the portion of the model you want to estimate, the operating point for estimation, and the input signal to use for estimation.

Open金宝appModel and Model Linearizer

打开仿真软件模型。金宝app

sys ='scdDCMotor'; open_system(sys)

To open theModel Linearizer, in the Simulink model window, in theAppsgallery, clickModel Linearizer.

Specify Portion of Model to Estimate

By default,Model Linearizeruses the linearization analysis points defined in the model (themodel I/Os) to determine where to inject the test signal and where to measure the frequency response. The modelscdDCMotorcontains predefined linear analysis points: an input point at the compensator output, and an open-loop output after the unit gain block. For this example, use these predefined model I/Os to obtain the frequency response of the inner loop of the model with the outer loop open.

If you want to obtain the frequency response of a different portion of the model, on theEstimationtab ofModel Linearizer, use theAnalysis I/Osdrop-down list. Analysis points for estimation work the same way as analysis points for linearization. For more information about linear analysis points, seeSpecify Portion of Model to Linearize.

Specify Operating Point for Estimation

执行频率响应估计a steady-state operating point of the model. You can compute or specify an operating point inModel Linearizerusing theOperating Pointdrop-down list. By default,Model Linearizeruses the operating point defined by the model initial conditions. For this example, use that operating point. For more information about operating points, seeAbout Operating Points.

Create Input Signal for Estimation

Frequency response estimation injects an input signal into the input analysis point you specify for estimation. For this example, configure a sinestream signal, which is a series of sinusoidal perturbations at frequencies you specify. (For more information about input signals, seeEstimation Input Signals.)

On theEstimationtab, in theInput Signaldrop-down list, selectSinestream. The Create sinestream input dialog box opens.
To specify frequency points for the input signal, click. In the Add frequencies dialog box, specify the frequency range and number of points for the input signal. The frequency points you specify are the frequencies at whichModel Linearizercomputes the estimated response.
For this example, specify a range from 0.1 to 100 rad/s. Also, specify 100 logarithmically spaced frequencies.

ClickOK. The added points are visible in the frequency content viewer of the Create sinestream input dialog box.

Select all these frequency points for the estimation input signal.
Specify the amplitude of the input signal. Enter1in theAmplitudefield. When you specify a scalar value,Model Linearizeruses the same amplitude for all frequencies.
ClickOKto create the sinestream input signal. The new input signal,in_sine1, appears in theLinear Analysis Workspace.