I am getting this error "The right and left hand sides must have the same number of elements" while computing g(i)

Question

RENJITH K 2022-1-20

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1632345-i-am-getting-this-error-the-right-and-left-hand-sides-must-have-the-same-number-of-elements-while

评论： Voss 2022-2-9

function [Sa,Sb,Sc]= control(xhatout,Vo_meas,v_ref,If_k)

% Sampling time of the predictive algorithm [s]

Ts = 33e-6;

%f = 50*(2*pi); % frequency [rad/s]

Vdc = 700; % DC-link voltage [V]

L = 2e-3;

C = 50e-6;

% 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];

% Previous Optimum vector and measured current at instant k-1

persistent x_old i_old v_old

% Initialize values

if isempty(x_old), x_old = 1; end

if isempty(i_old), i_old = 0+1j*0; end

if isempty(v_old), v_old = 0+1j*0;end

g = zeros(2,8);

% Read current reference inputs at sampling instant k

vk_ref = v_ref(1) + 1j*v_ref(2);

vk = Vo_meas(1) + 1j*Vo_meas(2);

io = [0 0 1]*xhatout;

for i = 1:8

% Cost function

vi = Vdc*x_old;

if_k1 = If_k+((Ts/L)*(vi-Vo_meas));

vc_k1 = vk+((Ts/C)*(If_k-io));

g(i) = abs(real(v_ref - vc_k1)) + abs(imag(v_ref - vc_k1));

end

% Optimization

[~,x_opt] = min(g);

% 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);

1 个评论
显示 -1更早的评论隐藏 -1更早的评论

Alan Weiss 2022-1-21

Please help us understand what you are doing by the following:

Mark up your code so that it looks like code. That helps us distinguish code from comments.
Report ALL of the red error message that MATLAB returns
Give us working code so we can reproduce your issue. This means give us the inputs you used for your function that cause it to throw an error

Alan Weiss

MATLAB mathematical toolbox documentation

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Voss 2022-1-21

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1632345-i-am-getting-this-error-the-right-and-left-hand-sides-must-have-the-same-number-of-elements-while#answer_879170

Try replacing this line:

g(i) = abs(real(v_ref - vc_k1)) + abs(imag(v_ref - vc_k1));

with this line:

g(:,i) = abs(real(v_ref(:) - vc_k1(:))) + abs(imag(v_ref(:) - vc_k1(:)));

The reason is that g(i) is a single element of g, but v_ref has (at least) 2 elements (don't know how many because we don't know what you send to the function), so the right-hand side is going to be non-scalar. From the initialization of g (g = zeros(2,8);) we can see the size of g is 2-by-8 so it's likely that each iteration of the loop is meant to set a column of g, i.e., g(:,i), rather than a single element g(i).

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

Answer 2

Cheng Syuan Ye 2022-2-9

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1632345-i-am-getting-this-error-the-right-and-left-hand-sides-must-have-the-same-number-of-elements-while#answer_892150

Hello, have you solved the problem, I am also researching recently, what is the final solution?

1 个评论
显示 -1更早的评论隐藏 -1更早的评论

Voss 2022-2-9

The answer to this particular question is:

https://www.mathworks.com/matlabcentral/answers/1632345-i-am-getting-this-error-the-right-and-left-hand-sides-must-have-the-same-number-of-elements-while#answer_879170

请先登录，再进行评论。