how to get fft analysis data from power gui to command and hence to exce;

Hey guys,

I am tring to export the fft analysis result from fft tools in power gui to excel. I have 4 input signal available and 3 signal number (i.e. it is a 3 phase sytem with 4 different currents). I tried to export it to MATLAB command window using following command.

 FFTDATA = power_fftscope(Currents);
FFTDATA.startTime=0.25;
FFTDATA.cycles = 1;
FFTDATA.fundamental = 50;
FFTDATA.maxFrequency = 2050;
FFTdata.input=3;
>> FFTDATA = power_fftscope(FFTDATA)
FFTDATA = 

  (%struct with fields:

               time: [60001×1 double]
            signals: [1×4 struct]
          blockName: 'Three_phase_PV_Mod_2018a_correct/Currents'
              input: 1%First input
             signal: 1% First signal
          startTime: 0.2500
             cycles: 1
        fundamental: 50
       maxFrequency: 2050
    THDmaxFrequency: Inf
            THDbase: 'fund'
           freqAxis: 'Hertz'
                mag: [41×1 double]
              phase: [41×1 double]
               freq: [41×1 double]
                THD: 8.0498
       samplingTime: 5.0000e-06
    samplesPerCycle: 4000
        DCcomponent: 1.0374
     magFundamental: 26.8804)
     
   
 FFTDATA.mag
 FFTDATA.phase
 FFTDATA.freq

However, I get magnitude, phase and frequency for 1st input and 1st signal only (as indicated by comment in the result above). How can I get data for other combinations? For example, 2nd signal 3rd inout and so on.

[Harold Esneider Pantoja Villota]

Hi, I have the same problem. Could you solve it?

Answer 1

[Rahul]

Hi Niraj,

I understand that you are working with the 'power_fftscope' function to extract FFT analysis results from 'Powergui' in a 'three-phase' system, and are facing challenges in accessing data for multiple 'inputs' and 'signals'. From the details provided, it appears that the current workflow extracts results only for the 'first input' and 'first signal' combination because 'power_fftscope' processes one channel at a time.

In such cases, the 'input' and 'signal' fields within the 'FFTDATA' structure can be iteratively updated to cover all required combinations. The process typically involves the following steps:

1. Running 'power_fftscope' for the desired 'blockName'.
2. Modifying 'FFTDATA.input' and 'FFTDATA.signal' in a loop to cycle through each available input and signal.
3. Exporting the 'mag', 'phase', and 'freq' values for each combination to a file (e.g., Excel).

For example:

% Define block name from your model
blockPath = 'Three_phase_PV_Mod_2018a_correct/Currents';

% Get initial FFTDATA struct
FFTDATA = power_fftscope(blockPath);

% Configure general parameters
FFTDATA.startTime = 0.25;
FFTDATA.cycles = 1;
FFTDATA.fundamental = 50;
FFTDATA.maxFrequency = 2050;


% Loop over inputs and signals
numInputs  = numel(FFTDATA.signals);  % Usually matches no. of available inputs
numSignals = numel(FFTDATA.signals(1).values); % Signals per input

allResults = {};

for inIdx = 1:numInputs
    
    for sigIdx = 1:numSignals
            FFTDATA.input  = inIdx;
            FFTDATA.signal = sigIdx;
            result = power_fftscope(FFTDATA);
        
            % Store or export data
            allResults{end+1} = table(result.freq, result.mag, result.phase, ...
                'VariableNames', {'Frequency_Hz', 'Magnitude', 'Phase_Deg'});
            
            % Example: write to Excel
            filename = sprintf('FFT_Input%d_Signal%d.xlsx', inIdx, sigIdx);
            writetable(allResults{end}, filename);
    end
end

By iterating through 'input' and 'signal' values, data for all available channels can be retrieved without restriction.

You can refer to the following documentation links for more information regarding exporting and power FFT of signals:

• Exporting Data to Excel: https://www.mathworks.com/help/matlab/ref/writetable.html
• Fourier analysis of simulation data signals: https://www.mathworks.com/help/sps/powersys/ref/power_fftscope.html