Unable to use the variable from workspace which is sent to the MATLAB workspace using 'To workspace' block of the Simulink.

I have a signal of my Simulink model which I have named as 'Fs'. I am using 'To workspace' block of the Simulink to store the signal in MATLAB workspace. The variable name is 'Fs' and the save format is 'Structure With Time' . The signal 'Fs' is not a vector, it is a 1 dimensional signal (basically it is a frequency signal of a Power Transmission System i..e. 50Hz ). I want to apply Empirical Mode Decomposition on this frequency signal. When I run the code it gives me the following error.. Error using load

Unable to read file 'IEEE_14_Bus_System_SM_FFR.mat'. No such file or directory.

Following is my code...

% Load the frequency signal from Simulink

load('IEEE_14_Bus_System_SM_FFR.mat', 'Fs');

freq_signal = Fs.signals.values;

disp(freq_signal)

% Step 1: Find extrema and obtain upper and lower envelopes

sampling_rate = 1000; % Hz

[~, upper_env] = envelope(freq_signal,round(sampling_rate/20),'peak');

[~, lower_env] = envelope(freq_signal,round(sampling_rate/20),'trough');

% Step 2: Compute the mean envelope

mean_env = (upper_env + lower_env)/2;

% Step 3: Initialize k and perform empirical mode decomposition

k = 1;

imf = [];

residual = freq_signal;

while true

% Step 3a: Extract the kth IMF

[imf_k,~,residual_k] = emd(residual-mean_env,'Display',0,'MaxNumIMF',1);

imf = [imf imf_k];

disp(imf)

% Step 3b: Check if the kth IMF is the last IMF

if size(residual_k,1) < 2

imf = [imf residual_k];

break;

end

% Step 3c: Prepare for next iteration

k = k + 1;

residual = residual_k;

end

% Step 4: Compute the residuals and extract additional IMFs

residual = freq_signal - imf;

imf2 = [];

while true

% Step 4a: Extract the next IMF

[imf_k,~,residual_k] = emd(residual-mean_env,'Display',0,'MaxNumIMF',1);

imf2 = [imf2 imf_k];

% Step 4b: Check if the kth IMF is the last IMF

if size(residual_k,1) < 2

imf2 = [imf2 residual_k];

break;

end

% Step 4c: Prepare for next iteration

residual = residual_k;

end

% Step 5: Compute the derivatives of the IMFs

for i = 1:size(imf,2)

deriv_imf(:,i) = gradient(imf(:,i));

end

for i = 1:size(imf2,2)

deriv_imf2(:,i) = gradient(imf2(:,i));

end

disp(deriv_imf2)

Can any staff members assist in this regard???

Answer 1

[Fangjun Jiang]

"Unable to read file 'IEEE_14_Bus_System_SM_FFR.mat'. No such file or directory."

Make sure you have that .mat file. Use Command Line to load it, check 'Fs' is there and have the right data.

[Taimoor Khan Mehmand]

I cannot see any .mat file in the folder that is related to this 'Fs' variable. I was expecting the .mat file for 'Fs' to be created in the same folder where I have this IEEE 14 Bus model. Is there any way to find the .mat file which the MATLAB created for that 'Fs' variable?

[Taimoor Khan Mehmand]

@Fangjun Jiang

I used 'dir' command to get all the .mat files and still couldn't find the 'IEEE_14_Bus_System_SM_FFR.mat' name file.

So my question is the name of the.mat file will be the same as my Simulink model file name? My Simlink model has the name " IEEE_14_Bus_System_SM_FFR" . Or the .mat file could be in a different directory?

[Fangjun Jiang]

The "To Workspace" block only saves the data to the workspace. After the simulation, check to make sure "Fs" exists and then run "save IEEE_14_Bus_System_SM_FFR.mat"

[Paul]

Can also use the To File block to save directly to .mat file from the Simulink model.

[Fangjun Jiang]

@Paul, good point!