THD calculation result same on different model

when I tried to calculate FFT on three different model its showing the same result but i am very sure the model is totally different. Why the result is coming like a default result.

[Voss]

Please post the relevant code.

[Chandra Prakash]

no any code error. result is same of all the three model.

[Voss]

The code throws no errors, but the results are the same for 3 different models, right?

Sounds like something is wrong in the code; maybe it's something as simple as only the last model's result is being plotted three times, perhaps because of a typo or a mistake in the logic of the code.

It is impossible to guess what the problem is without seeing the code.

[Chandra Prakash]

i also gussing same thing like by default result is showing three different model.

I want to calculate simply THD. I inter in Power gui and calculte THD result is showing same as three different model . How to rectify it .

Answer 1

[Sayan]

Hi Chandra Prakash,

I understand from your issue that you are getting the same THD results when you were trying to find them using the "FFT Analyzer" app of powergui block.Without investigating the model, it is difficult to find the exact reason for the issue.

However,an alternative way to find the THD is to use the THD block (available at Simscape / Electrical / Specialized Power Systems / Sensors and Measurements) which computes the THD for a periodic distorted signal. This block requires the "Fundamental frequency of the input signal (Hz)" to be filled with the fundamental frequency of the signal and output the result in decimal form.

You can find more information on the THD block in the following documentation:

https://www.mathworks.com/help/sps/powersys/ref/thd.html

Hope this helps in resolving the issue.