Menu

Discussion Forum

New Discussion
查找

Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.

How to stop COMSOL Events at an exact value?

Posted 2020年2月17日 GMT-5 11:21 General, Results & Visualization, Studies & Solvers Version 5.4 3 Replies

Paul Coman
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

I am simulating battery cycling using the Events interface. The voltage limits are V_high = 2.45 V and V_low = 2 V. The events are working okay, but there is a problem that I have encountered multiple times. The events never stop at those particular values/limits, as one can see in the figure below. Sometimes the events change at 2.43, sometimes at 2.46 but never at 2.4500 V or 2.000V as I would like to. I'm thinking that the time step (which is now strict) might help with this, but decreasing the time step for a long simulation time would slow the model significantly. I have also checked the option "Store solution before and after events" in the solver output settings.

Can anyone help me to make the events stop/change at exact values without compromising the computation speed?

Unfortunately I cannot send the model, but here are some extracts from the event settings:

3 Replies Last Post 2020年2月17日 GMT-5 16:38
Edgar J. Kaiser Certified Consultant
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 5 years ago 2020年2月17日 GMT-5 13:27
Updated: 5 years ago 2020年2月17日 GMT-5 13:51

Paul,

I had similar issues and increasing the scaling in the solver settings for the respective variables improved the situation. It can make the solver more sensitive to the criterion.

Maybe I should add that in case the time stepping is not resolving the event sufficiently then you won't get around reducing it.

Cheers Edgar

-------------------
Edgar J. Kaiser
emPhys Physical Technology
www.emphys.com
Paul, I had similar issues and increasing the scaling in the solver settings for the respective variables improved the situation. It can make the solver more sensitive to the criterion. Maybe I should add that in case the time stepping is not resolving the event sufficiently then you won't get around reducing it. Cheers Edgar
Paul Coman
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 5 years ago 2020年2月17日 GMT-5 15:47

This actually solved the problem, but I think it needs some work with the values to increase the precision and model stability. Thank you very much for the help!

This actually solved the problem, but I think it needs some work with the values to increase the precision and model stability. Thank you very much for the help!
Edgar J. Kaiser Certified Consultant
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 5 years ago 2020年2月17日 GMT-5 16:38

I am happy I was able to help.

-------------------
Edgar J. Kaiser
emPhys Physical Technology
www.emphys.com
I am happy I was able to help.

Note that while COMSOL employees may participate in the discussion forum, COMSOL® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team.

Suggested Content