How to solve 3 non-linear equations with 3 unknowns?

This is my code with solve,

G= 1000;

T=298;

Iscr = 9.71; %short citrcuit current

Vocr = 6; %Open circuit voltage

Im = 9.4; %MPP current

Vm = 5.5; %MPP coltage

K_Isc = 0.0005;

Vth = 0.8629*10^(-4)*T;

Iph= (G/1000) * Iscr* (1-(K_Isc)* (T-298 ));

n = 1;

%Io =x

%Rs = y

%Rsh = z

syms x y z

u = -Iscr + Iph - (x * ((exp((Iscr*y)/(n*Vth)))-1)) - ((Iscr*y)/z)==0;

v = Iph - (x * ((exp((Vocr)/(n*Vth)))-1)) - ((Vocr)/z)==0;

w = -Im + Iph - (x * ((exp((Vm + Im*y)/(n*Vth)))-1)) - ((Vm + (Im*y))/z)==0;

x0 = [10^-8,0.2,2500];

d = solve([u,v,w],[x,y,z],x0);

But I got this error:

>> fsolve18_2

Error using sym.getEqnsVars>checkVariables (line 87)

Second argument must be a vector of symbolic variables.

Error in sym.getEqnsVars (line 54)

checkVariables(vars);

Error in solve>getEqns (line 429)

[eqns, vars] = sym.getEqnsVars(argv{:});

Error in solve (line 226)

[eqns,vars,options] = getEqns(varargin{:});

Error in solve18_2 (line 24)

d = solve([u,v,w],[x,y,z],x0);

Answer 1

[Jyotsna Talluri]

We have to specify the equations to solve as the first input argument and variables for which the equation has to be solved as the second input argument to the solve function.There should not be any third argument .Moreover the third argument x0 which you specified is not being used anywhere.

d = solve([u,v,w],[x,y,z]);

d gives the values of x,y,z for which equations u,v,w are satisfied

Refer to the below link for more details

https://www.mathworks.com/help/symbolic/solve.html#buezrr6-2

Answer 2

[Alex Sha]

One of numerical solution looks like:

x: 4.49127153145489E-101
y: 0.0437692354838294
z: 867273686630772