MATLAB: Porblem with ode 45 solver

nonlinear state spaceode45

hi I am trying to solve nonlinear state space int the form
xdot= Ax+R(x,u)
y= S(x,u)
i have written a function given below
   function xdot = system(t,x,u)
    Tab=sqrt(2/3)*[cos(x(1)) cos(x(1)-2*pi/3) cos(x(1)+2*pi/3)
    -sin(x(1)) -sin(x(1)-2*pi/3) -sin(x(1)+2*pi/3)
    1/sqrt(2) 1/sqrt(2) 1/sqrt(2)]
    wc=2*pi*50;
    L=1.35e-3;
    R=.056;
    C=50e-6;
    Rc=.131;
    Lc=0.96e-3;
    P=10e3;
    Q=5e3;
    KpllI=5000;
    KpPPL=2.1;
    Kid2=460;
    Kpd2=1;
    Kiq2=460;
    Kpq2=1;
    udq= Tab*u;
    A=[0 KpllI 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
    0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
    0 0 -sqrt(2)*wc 0 wc*wc 0 0 0 0 0 0 0 0 0 0 0 0
    0 0 0 -sqrt(2)*wc 0 wc*wc 0 0 0 0 0 0 0 0 0 0 0
    0 0 -1 0 0 0 0 0 1 0 0 0 0 0 -1 0 0
    0 0 0 -1 0 0 0 0 0 1 0 0 0 0 0 -1 0
    0 0 0 0 0 0 0 0 -1 0 0 0 0 0 0 0 0
    0 0 0 0 0 0 0 0 0 -1 0 0 0 0 0 0 0
    0 0 0 0 0 0 0 0 -R/L 0 0 -1/L 0 0 0 0 0
    0 0 0 0 0 0 0 0 0 -R/L 0 0 -1/L 0 0 0 0
    0 0 0 0 0 0 0 0 0 0 -R/L 0 0 -1/L 0 0 0
    0 0 0 0 0 0 0 0 1/C 0 0 0 0 0 -1/C 0 0
    0 0 0 0 0 0 0 0 0 1/C 0 0 0 0 0 -1/C 0
    0 0 0 0 0 0 0 0 0 0 1/C 0 0 0 0 0 -1/C
    0 0 0 0 0 0 0 0 0 0 0 1/Lc 0 0 -Rc/Lc 0 0
    0 0 0 0 0 0 0 0 0 0 0 0 1/Lc 0 0 -Rc/Lc 0 
    0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 -Rc/Lc];
    w= KpllI*x(2)+KpPPL*udq(2);
    vld=Kid2*x(7)+Kpd2*(x(3)-x(9))+udq(1)-w*L*x(10);
    vlq=Kiq2*x(8)+Kpq2*(x(4)-x(10))+udq(2)-w*L*x(9);
    ;
R=[KpPPL*udq(2) % u(2)= voq
udq(2)
0
0
(udq(1)*P-udq(2)*Q)/((udq(2).^2)+(udq(1).^2))
(udq(1)*P+udq(2)*Q)/((udq(2).^2)+(udq(1).^2))
0
0
(vld*1/L)+w*x(10)
(vlq*1/L)-w*x(9)
0
w*x(13)
-w*x(12)
0
(-udq(1)*1/Lc)+w*x(16)
(-udq(2)*1/Lc)+w*x(15)
0];
xdot=A*x+R;
and the main file with 
t=0:100e-5:5;
wc=50;
u= [240*sqrt(2)*sin(wc*t+pi/2)
240*sqrt(2)*sin(wc*t-2*pi/3+pi/2)
240*sqrt(2)*sin(wc*t+2*pi/3+pi/2)];
x0=zeros(17,1);
odeOptions = odeset('RelTol',1e-6);
[t,y]      = ode45(@system,t,x0,odeOptions,u);
Tab=sqrt(2/3)*[cos(y(:,1)) cos(y(:,1)-2*pi/3) cos(y(:,1)+2*pi/3)
-sin(y(:,1)) -sin(y(:,1)-2*pi/3) -sin(y(:,1)+2*pi/3)
1/sqrt(2) 1/sqrt(2) 1/sqrt(2)];
udq= Tab*u;
The problem i am facing is that multiplication in the last line of code is giving error while in function file it gives no error but do not save the result. Kindly any body suggest me what i am doing wrong. Thanks

Best Answer

y(:,1), y(:,2) and y(:,3) are vectors of length numel(t).
So your matrix Tab is no longer 3x3.
Best wishes
Torsten.
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