Asked by Adnan
on 25 May 2014

I have a simple circuit for which I just need to obtain transfer function using Simulink. I have attached the image below. Any help would be appreciated. Thanks

Answer by Arkadiy Turevskiy
on 30 May 2014

Edited by Arkadiy Turevskiy
on 30 May 2014

Accepted Answer

You did not specify which transfer function you want. Let's assume you want a transfer function from input voltage to output voltage.

1. Start a new Simulink model and add Capacitor, Inductor and Resistor blocks from Simscape, Foundation Library, Electrical, Electrical Elements:

2. Add Controlled Voltage Source block (from Electrical Sources sublibrary) for providing input voltage, Voltage Sensor (Electrical Sensors sublibrary) for measuring output voltage, also add Electrical Reference (ground) (Electrical Elements sublibrary) and Solver Configuration block (Utilities sublibrary in Simscape). Connect the blocks as shown in your image, and specify all the values as shown in the image.

3. Add Simulink-PS Converter and PS -Simulink Converter blocks (also from Utilities sublibrary) for converting Simulink signal to physical signal and back. Use Step block as an input to the model, and Scope as the output.

4. Now right click on the line coming from Step block, and select Linear Analysis Points - Input Perturbation. Right click on the line coming from PS-Simulink Converter block and select Linear Analysis Points - Output Measurement. Note that this requires a license of Simulink Control Design .

5. In the menu select Analysis - Control Design - Linear Analysis

6. In the Linear Analysis Tool click on Linearize:

This linearizes the model, plots the step response (or some other graph if you selected something else, Bode plot, for example) and adds a computed linear system to Linear Analysis Tool workspace:

8. Copy linsys1 to MATLAB workspace (drag and drop in Linear Analysis Tool).Now you can look at the formula and use the linear system for further analysis and design

Arkadiy Turevskiy
on 20 Jun 2019

@ Rajan Kumar:

If the transformer only has passive elements - yes. If it has power semiconductors, then this approach will not work, as power semiconductors are essentially swithces with discontinuities and cannot be linearized. In that case you will need to use ac sweep approach - see my other comment below.

Kashif Mehmood
on 5 Sep 2019 at 13:36

Dear sir i have succesfully simulated your example.its really a nice example to understand.

i want to find out the transfer function of this circuit can you help me please .i have followed the steps but getting errors

Kashif Mehmood
on 5 Sep 2019 at 13:36

@ Rajan Kumar

did you get transfer function of the transformer

Sign in to comment.

Answer by Luigi Dilan Gervasio
on 19 May 2016

Sorry, I can obtain a symbolic transfer function without specific value of my component?

Luke Rucker
on 20 Nov 2018

This is the real question.

fima v
on 7 Jun 2019

yes i will be happy to have a parametric transfer function

Arkadiy Turevskiy
on 20 Jun 2019

No, creation of a symbolic transfer function from a Simscape model is not supported.

Sign in to comment.

Answer by Azzi Abdelmalek
on 25 May 2014

Do you want to simulate this circuit with Simulink? If yes , you will need a simscape toolbox

Answer by Nguyen Dinh Thuc
on 2 Jun 2017

From input "Step" to output "PS-Simulink Converter":

1000 s + 5e06

---------------------

s^2 + 6000 s + 2.5e07

Name: Linearization at model initial condition Continuous-time transfer function.

That is my result, I don't know why, please help me

Arkadiy Turevskiy
on 20 Jun 2019

you got a transfer function, what's the problem?

Sign in to comment.

Answer by Harshit Derasari
on 24 Jan 2018

Edited by Harshit Derasari
on 24 Jan 2018

Dan Herbison
on 6 Apr 2018

Arkadiy Turevskiy
on 20 Jun 2019

Sign in to comment.

Opportunities for recent engineering grads.

Apply Today
## 0 Comments

Sign in to comment.