function [sys,x0,str,ts] = UPFCModel1(t,x,u,flag,Tr1,Tr2,Ta1,Ta2,Cd,D,SB,Tj,r1s,a1s,r2s,a2s,aEqs,UCs,wN)
switch flag,

  %%%%%%%%%%%%%%%%%%
  % Initialization %
  %%%%%%%%%%%%%%%%%%
  case 0,
    [sys,x0,str,ts]=mdlInitializeSizes(t,x,u,r1s,a1s,r2s,a2s,aEqs,UCs,wN);

  %%%%%%%%%%%%%%%
  % Derivatives %
  %%%%%%%%%%%%%%%
  case 1,
    sys=mdlDerivatives(t,x,u,Tr1,Ta1,Tr2,Ta2,Cd,D,SB,Tj,r1s,a1s,r2s,a2s,aEqs,UCs,wN);

  %%%%%%%%%%
  % Update %
  %%%%%%%%%%
  case 2,
    sys=mdlUpdate(t,x,u);

  %%%%%%%%%%%
  % Outputs %
  %%%%%%%%%%%
  case 3,
    sys=mdlOutputs(t,x,u);

  %%%%%%%%%%%%%%%%%%%%%%%
  % GetTimeOfNextVarHit %
  %%%%%%%%%%%%%%%%%%%%%%%
  case 4,
    sys=mdlGetTimeOfNextVarHit(t,x,u);

  %%%%%%%%%%%%%
  % Terminate %
  %%%%%%%%%%%%%
  case 9,
    sys=mdlTerminate(t,x,u);

  %%%%%%%%%%%%%%%%%%%%
  % Unexpected flags %
  %%%%%%%%%%%%%%%%%%%%
  otherwise
    error(['Unhandled flag = ',num2str(flag)]);

end

% end sfuntmpl

%
%=============================================================================
% mdlInitializeSizes
% Return the sizes, initial conditions, and sample times for the S-function.
%=============================================================================
%
function [sys,x0,str,ts]=mdlInitializeSizes(t,x,u,r1s,a1s,r2s,a2s,aEqs,UCs,wN)

%
% call simsizes for a sizes structure, fill it in and convert it to a
% sizes array.
%
% Note that in this example, the values are hard coded.  This is not a
% recommended practice as the characteristics of the block are typically
% defined by the S-function parameters.
%
sizes = simsizes;

sizes.NumContStates  = 7;
sizes.NumDiscStates  = 0;
sizes.NumOutputs     = 7;
sizes.NumInputs      = 7;
sizes.DirFeedthrough = 0;
sizes.NumSampleTimes = 1;   % at least one sample time is needed

sys = simsizes(sizes);

%
% initialize the initial conditions
%
x0  = [r1s;a1s;r2s;a2s;aEqs;UCs;wN];

%
% str is always an empty matrix
%
str = [];

%
% initialize the array of sample times
%
ts  = [0 0];

% end mdlInitializeSizes

%
%=============================================================================
% mdlDerivatives
% Return the derivatives for the continuous states.
%=============================================================================
%
function sys=mdlDerivatives(t,x,u,Tr1,Ta1,Tr2,Ta2,Cd,D,SB,Tj,r1s,a1s,r2s,a2s,aEqs,UCs,wN)

sys(1)=(-x(1)+r1s+u(1))/Tr1;
sys(2)=(-x(2)+a1s+u(2))/Ta1;
sys(3)=(-x(3)+r2s+u(3))/Tr2;
sys(4)=(-x(4)+a2s+u(4))/Ta2;
sys(5)=x(7)-wN;
sys(6)=u(5)*SB/Cd/x(6);
sys(7)=wN/Tj*(u(7)-u(6)-D/wN*(x(7)-wN));

% end mdlDerivatives

%
%=============================================================================
% mdlUpdate
% Handle discrete state updates, sample time hits, and major time step
% requirements.
%=============================================================================
%
function sys=mdlUpdate(t,x,u)

sys = [];

% end mdlUpdate

%
%=============================================================================
% mdlOutputs
% Return the block outputs.
%=============================================================================
%
function sys=mdlOutputs(t,x,u)
if(x(1)<=0)
   x(1)=0;
elseif(x(1)>=pi/2)
   x(1)=pi/2;
else
   x(1)=x(1);
end

if(x(3)<=0)
   x(3)=0;
elseif(x(3)>=pi/2)
   x(3)=pi/2;
else
   x(3)=x(3);
end
x(2)=mod(x(2),2*pi);
x(4)=mod(x(4),2*pi);

   
sys=x;
% end mdlOutputs

%
%=============================================================================
% mdlGetTimeOfNextVarHit
% Return the time of the next hit for this block.  Note that the result is
% absolute time.  Note that this function is only used when you specify a
% variable discrete-time sample time [-2 0] in the sample time array in
% mdlInitializeSizes.
%=============================================================================
%
function sys=mdlGetTimeOfNextVarHit(t,x,u)

sampleTime = 1;    %  Example, set the next hit to be one second later.
sys = t + sampleTime;

% end mdlGetTimeOfNextVarHit

%
%=============================================================================
% mdlTerminate
% Perform any end of simulation tasks.
%=============================================================================
%
function sys=mdlTerminate(t,x,u)

sys = [];

% end mdlTerminate