Variable 'x_opt' is not fully defined on some execution paths.

Question

Hussain SARWAR KHAN 2018-3-13

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/388113-variable-x_opt-is-not-fully-defined-on-some-execution-paths

评论： Walter Roberson 2022-10-27

i am write this code in userdefined Simulink function For model predictive control but this code has some error so what i have too do.

function [Sa,Sb,Sc] = control(I_ref,I_meas)
% Variables defined in the parameters file
% Sampling time of the predictive algorithm [s]
Ts = 25e-6;
% Load parameters
R = 10; % Resistance [Ohm]
L = 10e-3; % Inductance [H]
e = 100; % Back-EMF peak amplitude [V]
f_e = 50*(2*pi); % Back-EMF frequency [rad/s]
Vdc = 520; % DC-link voltage [V]
% Current reference
I_ref_peak = 10; % Peak amplitude [A]
f_ref = 50*(2*pi); % Frequency [rad/s]
% Voltage vectors
v0 = 0;
v1 = 2/3*Vdc;
v2 = 1/3*Vdc + 1j*sqrt(3)/3*Vdc;
v3 = -1/3*Vdc + 1j*sqrt(3)/3*Vdc;
v4 = -2/3*Vdc;
v5 = -1/3*Vdc - 1j*sqrt(3)/3*Vdc;
v6 = 1/3*Vdc - 1j*sqrt(3)/3*Vdc;
v7 = 0;
v = [v0 v1 v2 v3 v4 v5 v6 v7];
% Switching states
states = [0 0 0;1 0 0;1 1 0;0 1 0;0 1 1;0 0 1;1 0 1;1 1 1];
% Optimum vector and measured current at instant k-1
persistent x_old i_old
% Initialize values
if isempty(x_old)
   x_old = 1;
end
if isempty(i_old)
   i_old = 0+1j*0;
end
g_opt = 1e10;
% Read current reference inputs at sampling instant k
ik_ref = I_ref(1) + 1j*I_ref(2);
% Read current measurements at sampling instant k
ik = I_meas(1) + 1j*I_meas(2);
% Back-EMF estimate
e = v(x_old) - L/Ts*ik - (R - L/Ts)*i_old;
% Store the measured current for the next iteration
i_old = ik;
for i = 1:8
% i-th voltage vector for current prediction
v_o1 = v(i);
% Current prediction at instant k+1
ik1 = (1 - R*Ts/L)*ik + Ts/L*(v_o1 - e);
% Cost function
g = abs(real(ik_ref - ik1)) + abs(imag(ik_ref - ik1));
% Selection of the optimal value
if (g<g_opt)
g_opt = g;
x_opt = i;
end
end
% Store the present value of x_opt
x_old = x_opt;
% Output switching states
Sa = states(x_opt,1);
Sb = states(x_opt,2);
Sc = states(x_opt,3);
63end

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Naresh Rayavarapu 2022-10-27

sir have you found the solution for the script X_opt error

Walter Roberson 2022-10-27

在 MATLAB Online 中打开

 if (g<g_opt)
   g_opt = g;
   x_opt = i;
 end

Suppose that condition is never true, then what is x_opt set to?

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Answer 1

Walter Roberson 2018-3-13

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/388113-variable-x_opt-is-not-fully-defined-on-some-execution-paths#answer_309909

The message is correct. You do not define the value of x_opt under the circumstance that none of the computed g values are less than the 1e10 that you initialize g_opt to.