function a = DFclass(varargin)% constructor of the class Doubly-Fed Induction Generator% == DFIG ==global Settingsswitch nargin case 0  a.con = [];  a.n = 0;  a.bus = [];  a.vbus = [];  a.wind = [];  a.dat = [];  a.omega_m = [];  a.theta_p = [];  a.idr = [];  a.iqr = [];  a.store = [];  a.u = [];  a.ncol = 24;  a.format = ['%4d %4d ',repmat('%8.4g ',1,21),'%2u'];  if Settings.matlab, a = class(a,'DFclass'); end case 1  if isa(varargin{1},'DFclass')    a = varargin{1};  else    error('Wrong argument type')  end otherwise  error('Wrong Number of input arguments')end