Photovoltaic model (5 parameter model)

Hi everyone

I have attempted to model the DC power output (at maximum power point, i.e max Impp_ and Vmpp_ values) for a set of photovoltaic modules. The open circuit voltage (Voc_) and Impp_ and Vmpp equations have been solved using numerical methods (which is where I think the mistake lies). Basically, there is a mistake(s) in the coding since in come case I get a power output that is higher than the nominal power output of the PV panel

Any ideas/suggestions are much appreciated

     for iteration = 1:10 % for iteration = 1:10 %10000 iterations

        Voc_(:,:,K)= Voc_ref(K) + b_Voc(K).*(Tc(:,:,K)-Tstc);

        Voc_old(:,:,K) = Voc_(:,:,K);

        Voc_(:,:,K) = ns(K).*Vt(:,:,K).*log((Iph_G(:,:,K).*Rsh_ref(K)-Voc_(:,:,K)./Io_ref(K).*Rsh_ref(K)));

        error(:,:,K) = Voc_old(:,:,K) - Voc_(:,:,K);

        if abs(error(:,:,K))/Voc_(:,:,K) < 1e-6 % The iteration has converged

            break
        end
    end

    Voc_G(:,:,K) = Voc_(:,:,K); %%% ???? check this ?????  %%%%%

    Voc_T(:,:,K) = Voc_ref(K) + b_Voc(K).*(Tc(:,:,K) - Tstc);

    Io_T(:,:,K) = (Isc_T(:,:,K)-((Voc_T(:,:,K) - Isc_T(:,:,K).* Rs(K))./Rsh(:,:,K)))...
        .*exp((-Voc_T(:,:,K))./(ns(K).*Vt(:,:,K))); % Dark saturation current temperature

    Iph_T(:,:,K) = Io_T(:,:,K).*exp((Voc_T(:,:,K))./(ns(K).*Vt(:,:,K)))+(Voc_T(:,:,K)./Rsh(:,:,K));

    Voc_GT(:,:,K) = Voc_G(:,:,K)+(b_Voc(K).*(Tc(:,:,K)-Tstc)); % Radiation and temp of Voc

    Isc_GT(:,:,K) = Isc_G(:,:,K).*(1+(a_Isc(K)/100).*(Tc(:,:,K)-Tstc));

    Io_GT(:,:,K) = (Isc_GT(:,:,K)-((Voc_GT(:,:,K)-Isc_GT(:,:,K).*Rs(K))./Rsh(:,:,K)).*exp(-1.*(Voc_GT(:,:,K)/ns(K).*Vt(:,:,K))));
    Iph_GT(:,:,K) = Io_GT(:,:,K).*exp(Voc_GT(:,:,K)./ns(K).*Vt(:,:,K))+(Voc_GT(:,:,K)./Rsh(:,:,K));

    %%Vmpp & Impp
    %Initialization

    Vmpp_(:,:,K) = Voc_GT(:,:,K)./Voc_ref(K).*Vmp_ref(K);
    Impp_(:,:,K) = Isc_GT(:,:,K)./Isc_ref(K).*Imp_ref(K);
    w  = 0.04; % for SUR

    for iteration = 1:10

        Vmpp_(:,:,K) = (1-w).*Vmpp_(:,:,K)+w.*(Voc_GT(:,:,K)-Impp_(:,:,K).*Rs(K)+ns(K).*Vt(:,:,K)...
            .*log(((Isc_GT(:,:,K)-Impp_(:,:,K)).*(Rs(K)+Rsh(:,:,K))-Vmpp_(:,:,K))./(Isc_GT(:,:,K)...
            .*(Rs(K)+Rsh(:,:,K))-Voc_GT(:,:,K))));

        Impp_(:,:,K) = (1-w).*Impp_(:,:,K)+w.*(Vmpp_(:,:,K).*(1./Rsh(:,:,K)+(Isc_GT(:,:,K)...
            .*Rsh(:,:,K)-Voc_GT(:,:,K)+Isc_GT(:,:,K).*Rs(K)).*exp((Vmpp_(:,:,K)+Impp_(:,:,K)...
            .*Rs(K)-Voc_GT(:,:,K))/ns(K)./Vt(:,:,K))./ns(K)./Vt(:,:,K)./Rsh(:,:,K))./(1+Rs(K)...
            ./Rsh(:,:,K)+Rs(K).*(Isc_GT(:,:,K).*Rsh(:,:,K)-Voc_GT(:,:,K)+Isc_GT(:,:,K).*Rs(K))...
            .*exp((Vmpp_(:,:,K)+Impp_(:,:,K).*Rs(K)-Voc_GT(:,:,K))./ns(K)./Vt(:,:,K))./ns(K)./Vt(:,:,K)./Rsh(:,:,K)));

        parameter_new(:,:,K) = [Impp_(:,:,K); Vmpp_(:,:,K)];
        if iteration ~= 1
            mismatch(:,:,K) = abs((parameter_new(:,:,K)-parameter_old(:,:,K))./parameter_new(:,:,K));
            if (norm(mismatch(:,:,K),'inf') < 1e-6)
                break;
            end
        end

        parameter_old(:,:,K)= [Impp_(:,:,K); Vmpp_(:,:,K)];
        PV_power_output(:,:,K) = Vmpp_(:,:,K).*Impp_(:,:,K);
    end

end

[Walter Roberson]

Probably very few of us are familiar with those particular equations, and you have not given any sample inputs and expected outputs that we could test with.

[Andrew Alkiviades]

I emailed you all the info (m file and spreadsheet)

Hope thats ok!

Andrew

[Lucardo Montreuil Jean]

Hi everyone. I get the same probleme, could anyone send the m.file. Please.