Optimization of bandwidth and phase margin of a transfer function

Forum|Forum|8 years ago
June 6, 2017
3 replies
5635 views

Hi all, I have a question regarding the selection of a proper value for a parameter from a list based on the evaluation of its transfer function.

As shown here, if I have a variable a, whose value can be selected from a list. A transfer function TF(s,a) is an s-domain function including this variable. We can calculate bandwidth and phase margin of a selected value of "a". I am wondering if it is possible to specify the criteria for the bandwidth and phase margin, and let Mathcad follows these criteria and select the optimized value of "a" from the list?

Thank you!

optimize BW and PM.JPG

1_optimize-bandwidth-and-phase-margin-xmcd.zip

Other

Best answer by LucMeekes

I've extended the ranges of a, b and c values to 9 values each, and made a few changes to the code to allow it to deal with imaginary numbers.

It takes a little while to calculate all 729 results, but you've got something to choose from !

Success!
Luc

W

Werner_E

25-Diamond I

See if the attached file helps-

1_optimize-bandwidth-and-phase-margin-WE-xmcdz.zip

Y

yhuang-3

Author

1-Visitor

Hi Werner, thank you for much for your help! Your solutions works well. Now can I ask for a more complicated scenario, by extending the numbers of variables to 3? Thank you!

3 variables for BW PM optimization.PNG

1_optimize-bandwidth-and-phase-margin2-xmcd.zip

W

Werner_E

25-Diamond I

In this case, if you continue the brute force way of trying all combinations, you would make TF a function of b an c as well -> TF(s,a,b,c):=...

The pickValue routine would have three options as arguments (one for a, b and c) and instead of the one for loop you would use three nested for loops (for a-options, b-options and c-options) and innermost again the same statements which calculates BW_OK and PM_OK and jumps out at the very first fitting combination found.