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