this is with regards to this article https://in​.mathworks​.com/help/​ident/exam​ples/estim​ating-tran​sfer-funct​ion-models​-for-a-boo​st-convert​er.html ....I have gone through the procedure and it has worked upto the frestimate only, error thereafter.

I want to estimate the transfer function simmilarily as in https://in.mathworks.com/help/ident/examples/estimating-transfer-function-models-for-a-boost-converter.html .After evaluating frestimate command however I get an error after inputting the command sysA = tfest(sysData,4)

figure, bode(sysData,'r*',sysA,bopt). Please help! Also in the step immediately before it I get error in loading the system data.It shows no such file or directory.. please help...I need to do it urgently.

[Walter Roberson]

Do you have the System Identification toolbox installed? It is an option extra-cost product.

[Asma Bh]

Yes system identification toolbox is already installed

[Walter Roberson]

Must not have been "urgent" I guess.

[Asma Bh]

well I am sorry for not responding quickly. I am grateful for your help. I have the required sys ident toolboox installed. You can check in attatched screenshot where I get stuck in matlab. I have got the bode and other plots but having problems in estimating the tf. Please also check if there is anything missing in the workspace for loading the data.

[Asma Bh]

If you can help estimate the transfer function I will send you my converter model.But I also need to learn to do it by myself.

Answer 1

[Rajiv Singh]

The data file "iddemo_boostconverter_data.mat" ships with System Identification Toolbox; stored under toolbox/ident/iddemos folder. Can you check if you have this file present? If so, are you able to load in MATLAB workspace? If not, this may point to a possible corruption in the installation and you should contact MathWorks Technical Support.

[Walter Roberson]

I just noticed that we have no information about which release was being used.

Answer 2

[Walter Roberson]

nonidealzeta_data is not a Mathworks supplied file and is not available anywhere in the internet. Possibly it is intended to be the result of executing the model nonidealzeta which is not supplied by Mathworks and which is not easily found. Perhaps the model is from a paper by Garg and Pathak, I cannot quite tell.

You are having difficulty loading a file that we have no reason to expect exists.

Also on a different topic: your display shows a problem on line 9 of roots.m . The Mathworks supplied roots.m has more than that many lines of comments at that point. Either you have badly corrupted roots.m or else you have your own roots function on the path that is interfering. You should look at

which -all roots

and I suspect that you will find that you have your own roots.m or else that something you installed is providing its own roots.m that is interfering. When you have interfering files then execution of code can get strange, including potentially causing a valid model to fail without saving a file that you expect.