There is a problem with the Simscape Varistor Model

Hi,

I wanted to notify that there is an error with the Varistor component in Simscape. To understand the model see the following component documentation Varistor -Voltage Dependent Resistor.

In this documentation we see that the ir the option to implement the power law for modeling the varistor, and the piecewise equation is the folowing:

Using Desmos (left) and simulating the simscape model (right), this is how the V-I curve from one another:

The figure on the right was obtained applying a ramp current signal.

As yo can see, derivative in the normal to upturn transition is not continuous wich makes the graph on the right not look smooth. So clearly there is an error with the simscape model related to the constant "k".

I basically wanted to notify this issue, in case some one has encountered the same problem. And of course to make this error visible to make the Matlab staff to take note and fix it.

Thanks!

[Pat Canny]

I recommend contacting MathWorks Technical Support. This question requires more information.

Answer 1

[Sabin]

This has been adressed in the following answer:

https://www.mathworks.com/matlabcentral/answers/1950263-problem-with-varistor-created-with-simscape-custom-component