Difficulty Getting to MPP via Incremental Conductance on Simulink.

%CODE
function out = fcn(V, I, Vo, Io, d, step)
dv = V - Vo;
di = I - Io;
if(dv == 0)
    if(di == 0)
        out = d;
    else
        if(di > 0)
            %increase duty cycle
            d=d-step;
        else
            %decrease duty cycle
            d=d+step;
        end
        out = d;
    end
else
    if(di/dv == -(I/V))
        out = d;
    else
        if(di/dv > -(I/V))
            %decrease duty cycle
            d=d-step;
        else
            %increase duty cycle
            d=d+step;
        end
        out = d;
    end
end
%CODE

We have this model for Inc Cond for solar panel MPPT project. The code is also provided for the block, our output used to be perfect when our power gui was set to 1e-7 but our other models are using 1e-6 and we have tried messing with the step size constant to no avail. We are unsure what is going on, if it is relevant we are using a synchronous buck converter for the output of our solar panel.

[Walter Roberson]

It is better to post code as text rather than as image. There are no known MATLAB versions that are able to execute images.

[Walter Roberson]

if (di/dv == -(I/V))

first off, you compute di/dv and -(I/V) twice. It would be more efficient to assign the parts into variables and then compare the variables.

Secondly, there would be fewer fragile division operations if you would to cross-multiply to compare di*V and -I*dv