How should the change in delta V (change in voltage) look like in a perturb and observe algorithm?

Hello all,

I am currently working on an IEEE paper which is about extracting maximum power under partial shading of PV panels using Modular Multilevel Converter (MMC). In order to achieve maximum power, I am using a Maximum Power Point Tracking Algorithm called Perturb and Observe(P&O). The output of this P&O is the change in delta V. I am then sending this delta V to a control architecture for the MPPT controller. I am able to simulate the model in MATLAB/SIMULINK using a MATLAB function block. For testing purposes, I am giving a constant voltage of 400 V and a sinusoidal current of 177 A. I have attached the code and some figures (output graph and the SIMULINK model) for your reference. I need to know if that is what is expected as the output for the change in Voltage. It would help me if you could take a look at the graph and give me inputs and suggestions.

Thank you.

 if true
    function dv = pand0(V, I)
    persistent Pold Vold;
    if isempty(Vold)
       Vold = 0;
       Pold = 0;
    end
    P = V*I;
    dV = V - Vold;
    dP = P - Pold;
    dalpha = 0.001;
    if dP > 0
       if dV > 0
          V_new = V + dalpha;
       else
          V_new = V - dalpha;
       end
    else
        if dV > 0
           V_new = V - dalpha;
        else
           V_new = V + dalpha;
        end
    end
    Pold = P;
    Vold = V_new;
    dv = dV;

end

Answer 1

[Sabin]

The Perturb and Observe method will periodically perturb the array terminal voltage or current and then detect changes in PV power output. If power decreases, operating point is moved in the opposite direction.

A good starting point to learn more about PV simulation and achieving MPPT is this example in Simscape electrical:

https://www.mathworks.com/help/sps/ug/three-phase-grid-connected-in-pv-system.html