Why varistor block behaves linearly?(like a resistance)

I'm in an investigation project that needs to simulate varistors under a current impulse.

I'm having one problem at every step I do, I haven't had this kind of problems in Simulink before.

I enter the impulse and the residual voltage that I get is not what it should be like a varistor that behaves non-linearly, I get the result of a linear component like a lonely resistance.

I remember doing something very similar in the past and got the same wrong output.

What I see in the scope has to be equal to the three green graphs of the screen capture.

I tried first with just 1 varistor and what I get is just the behavior of a resistance.

Is common this problem in simulink with the resistor block? Or, I am missing something?

*I use matlab online in the lab.

Thank you in advance

Answer 1

[Kartik]

Hi,

It's possible that there may be an issue with the way you're modeling the varistor in Simulink. Varistors exhibit non-linear behavior, which means that their resistance changes with the applied voltage.

If you're using the standard resistor block in Simulink, it only models linear resistance and cannot capture the non-linear behavior of the varistor.

To model a varistor in Simulink, you will need to use a non-linear resistor block, such as the "Piecewise Linear Resistor" block or the "Nonlinear Resistor" block. These blocks allow you to define the voltage-current relationship for the varistor and will give you the non-linear behavior that you're looking for.

Another thing to check is that your simulation parameters are set appropriately. Make sure that your simulation time is long enough to capture the transient behavior of the varistor, and that your timestep is small enough to accurately capture the non-linear behavior.

Additionally, make sure that the parameters you're using for the varistor (such as its breakdown voltage and resistance) are accurate and appropriate for the application you're simulating.