Error in Simulink , output sizes of the block

Hello;

I've tried to writing matlab code for determining global peaks for shading pv panel and set the output as maximum power, region and short circuit current to be used in next block. My inputs are PV voltage and current from PV block, both are 3000x1 double sizes.

However, when I run the program it shows the error of

_Simulink does not have enough information to determine output sizes for this block. If you think the errors below are inaccurate, try specifying types for the block inputs and/or sizes for the block output_ s.

I expected the outputs to be single number.

The code is below;

function [Region,Isc_step,P_Gmppt] = initial(V1, I1)
P1= V1.*I1;

[P_Lmppt,V_Lmppt] = findpeaks(P1,V1);
P_Gmppt = max(P_Lmppt);                         % find global max

V_Gmppt_loc = find(P_Gmppt == P_Lmppt);
V_Gmppt = V_Lmppt(V_Gmppt_loc);                 % find V at global max

P_inv = P_Gmppt - P1;                           % inverse the data
[P_drop_Lmppt,V_drop_Lmppt] =findpeaks(P_inv,V1);
V_drop = max(V_drop_Lmppt);

V_drop_loc = find(V1 == V_drop);
P_drop = P_inv(V_drop_loc);

% calculate shading short circuit current (after step)
I_shade = I1(V_drop_loc:end,:);                  % filter I that beyond V_drop
V_shade = V1(V_drop_loc:end,:);                  % filter I that beyond V_drop

Isc_step = I_shade(1);

if V_Gmppt > V_drop
    Region = 1;
else
    Region = 2;
end

end

The figure for simulink is

Any suggestions for solving this? Many thanks in Advanced

Answer 1

[Birdman]

Make three assignments at the beginning of your function: If the outputs are scalar

Region=0;
Isc_step=0;
P_Gmppt=0;

If vector

Region=zeros(n,1);
Isc_step=zeros(n,1);
P_Gmppt=zeros(n,1)%n is the row number you define

By this way, Simulink has an idea of what type and dimension the output is going to be.

[Jirada Gosumbonggot]

Dear cvklpstunc

Thank you very much for your help, I think the problem of variables can be solved. But I have got another problem. When I try running the program, there's an error on the upper bound value of V_drop_loc.

Output 'V_drop_loc' has variable size but the upper bound is not specified; explicit upper bound must be provided.

I have tried using coding.varsize command for it

coder.varsize('V_drop_loc', [1, varargin{1}];

but there's still error. I'm not sure if I did it correctly.

any recommendation? Thank you in advanced

[Birdman]

Same thing goes for V_drop_loc. You have to initialize that variable because Simulink has no idea for it. Try writing

V_drop_loc=zeros(n,1);%n is the row number you define

By this way, Simulink will know that that variable will have maximum of n numeric variables at one time step.

[Jirada Gosumbonggot]

Dear Cvklpstunc Thank you so much, I follow your guide and it works. And I also set my simulation mode from continuous to discrete and it helps (not sure why).

thanks again

[Palyam Prakash]

thank you so much sir

its working

[FRANCOIS GONZALES PALACIOS]

Excellent!! thanks so much!!