Issue with parameter estimation in Battery(Table-based) block

Hi,

I am in between estimating the parameter of 1RC battery model(using battery(table based) block). I have set initial parameters for V0,R0,R1 and Tau1. Since i have experimental pulse discharge data values of 6190 seconds, my paramters for estimations are also column vector of size 6190X1. i am using parameter estimation toolbox for optimization and least square algorithm. in new experiment tab, i have set pulse discharge data values as "Output" variable. in parameter, i set V0,R0,R1 and Tau1 with initials guess of all paramters. when running the estimation, the app shows its estimating (at bottom), and the model is running the iterations. but at the end, the the estimation output is "Initial point is local minimum" and iteration=0 and F-Count=513. also the estimated parameters plot is empty. I am unable to guess what is happening?? please help. Thanks

Answer 1

[Sivsankar]

Hi @SUDEEP SINGH RAWAT

I understand that you are trying to estimate parameters for your battery block. After running the estimation, you are receiving the output "Initial point is a local minimum." This output suggests that the initial parameter values might already satisfy the optimization criteria, or there might be an issue with the setup. So try changing your initial guesses. You can refer to the following MATLAB Answers for more insights on this output. Please note that they are not specific to your scenario:

• https://www.mathworks.com/matlabcentral/answers/1465914-optimization-initial-point-is-a-local-minimum-problem
• https://www.mathworks.com/matlabcentral/answers/161940-initial-point-is-a-local-minimum

Another reason you might be facing this issue could be that the bounds for the parameters within the parameter estimation session are not set correctly. Ensure that the 'Minimum' and 'Maximum' bounds for each parameter are filled in, especially if they are currently defined as -inf to inf.

You can also refer to the following MathWorks webinars to learn more about estimating battery parameters:

• https://www.mathworks.com/videos/automating-battery-model-parameter-estimation-using-experimental-data-81987.html?s_iid=disc_rw_pm_bod
• https://www.mathworks.com/videos/estimating-parameters-of-a-battery-68957.html

I hope this helps!

[SUDEEP SINGH RAWAT]

Thank you. it was a great help!