MATLAB: I am using a simple code to calculate solution of three nonlinear equations using fsolve. But i get the error saying “Error using vertcat Dimensions of matrices being concatenated are not consistent.” I checked the dimensions they are equal. Help!

Question

k=1.38*10^-23;

T=25+273;

q=1.6*10^-19;

Vt=k*T/q;

Jsc=12.5e-3;

Voc=0.951;

Rp=118000;

Vmp=0.833;

Jmp=11.15e-3;

f=@(z) [4.735 – ((z(2).*Vt)/Jsc)- z(1) +0*z(3);

       (Jsc-(Voc/Rp))/(exp(Voc/(z(2).*Vt)-1))-z(3) + 0*z(1);
       z(3).*(exp((Vmp-Jmp.*z(1))/(z(2).*Vt))-1)+ (Vmp-Jmp.*z(1))/Rp - Jsc -Jmp];

fsolve(f,[1;1;1e-6])

Answer 1

In matrix calculations, MATLAB interprets any spaces between operations as different elements. Take out the spaces and it works:

f=@(z) [4.735-((z(2).*Vt)./Jsc)-z(1)+0*z(3);
         (Jsc-(Voc./Rp))/(exp(Voc./(z(2).*Vt)-1))-z(3)+0*z(1);
         z(3).*(exp((Vmp-Jmp.*z(1))./(z(2).*Vt))-1)+ (Vmp-Jmp.*z(1))./Rp-Jsc-Jmp];
ze = fsolve(f,[1;1;1e-6])

produces:

ze =
       2.7061e+000
     986.7183e-003
     422.4400e-018