DFIG_init6.m

clear

% DFIG parameters -> Rotor parameters referred to the stator side
f = 50; % Stator frequency (Hz)
Ps = 2e6; % Rated stator power (W)
n = 1500; % Rated rotational speed (rev/min)
Vs = 690; % Rated stator voltage (V)
Is = 1760; % Rated stator current (A)
Tem = 12732; % Rated torque (N.m)

p=2; % Pole pair

u = 1/3; % Stator/rotor turns ratio
Vr = 2070;    % Rated rotor voltage (non-reached) (V) 
smax = 1/3;   % Maximum slip
Vr_stator = (Vr*smax) *u;    % Rated rotor voltage referred to stator (V)
Rs = 2.6e-3;    % Stator resistance(ohm)                
Lsi = 0.087e-3; %  Leakage inductance (stator & rotor) (H)                 
Lm = 2.5e-3; %  Magnetizing inductance (H)
Rr = 2.9e-3; % Rotor resistance referred to stator (ohm)
Ls = Lm + Lsi; % Stator inductance (H)
Lr = Lm + Lsi; % Rotor inductance (H)
% Vbus = Vr_stator*sqrt(2); % DC de bus voltge referred to stator (V)
Vbus = 1150; % as in tutorial 4

sigma = 1-Lm^2/(Ls*Lr);

Fs = Vs*sqrt(2/3)/(2*pi*f);  % Stator Flux (aprox.) (Wb)
J = 127; % Inertia, originally 127, reduced by 2 to make the response faster
D = 1e-3; %damping 

fsw = 4e3; 
Ts =  1/fsw/50;

kT = -1.5*p*(Lm/Ls)*Fs; % kT, coef of output of the speed controller  

tau_i = (sigma*Lr)/Rr;
tau_n = 0.05; 
wni = 100*(1/tau_i)/5;
wnn = 1/tau_n;

kp_id = (2*wni*sigma*Lr)-Rr;
kp_iq = kp_id;

ki_id = (wni^2)*Lr*sigma;
ki_iq = ki_id;

kp_n = (2*wnn*J)/p; %kp_n = (2*wnn*J)/p;
ki_n = (wnn^2)*J/p; %ki_n = (wnn^2)*J/p;


% Three blade wind turbine mode
N = 100; % Gearbox ratio
Radio= 42; % blade radius 
ro= 1.225; % Air density

% Cp and Ct curves
beta=0;  % Pitch angle
ind2=1;

for lambda=0.1:0.01:11.8
    lambdai(ind2)= (1./((1./(lambda-0.02.*beta) + (0.003./ (beta^3+1)))));
    Cp(ind2)=0.73*(151./lambdai(ind2) - 0.58*beta - 0.002.*beta^2.14-13.2).*(exp(-18.4./lambdai (ind2))); 
    Ct(ind2)=Cp(ind2)/lambda;
    ind2=ind2+1;
end

tab_lambda=[0.1:0.01:11.8];


% Kopt for MPPT
Cp_max = 0.44; 
lambda_opt = 7.2;
Kopt = ((0.5*ro*pi* (Radio^5) *Cp_max)/(lambda_opt^3));
% Power curve in fucntion of wind speed

P = 1.0e+06 *[0,0,0,0,0,0,0,0.0472,0.1097,0.1815,0.2568,0.3418, ...
            0.4437,0.5642, 0.7046, 0.8667,1.0518,1.2616, 1.4976, 1.7613,2.0534,...
            2.3513,2.4024,2.4024,2.4024, 2.4024,2.4024,2.4024];
V = [0.0000,0.5556,1.1111,1.6667,2.2222,2.7778,3.3333,3.8889, 4.4444,... 
    5.0000,5.5556,6.1111,6.6667,7.2222,7.7778,8.3333,8.8889,9.4444, ...
    10.0000,10.5556,11.1111, 11.6667,12.2222,12.7778,13.3333, 13.8889,...
    14.4444,15.0000];
% figure
% subplot(1,2,1)
% plot(tab_lambda, Ct, 'linewidth',1.5)
% xlabel('\lambda', 'fontsize',14)
% ylabel('Ct', 'fontsize',14)
% subplot(1,2,2)
% plot (V, P, 'linewidth', 1.5)
% grid
% xlabel('Wind speed (m/s)', 'fontsize',14)
% ylabel('Power (W)', 'fontsize',14)


% Grid side converter
Cbus = 80e-3; % DC bus capacitance
Rg = 20e-6; % Grid side filter's resisatance
Lg = 400e-6; % Grid side filter's inductance
Kpg = 1/(1.5*Vs*sqrt(2/3));
Kqg = -Kpg;

% PI regulators
tau_ig = Lg/Rg;
wnig = 60*2*pi;

kp_idg = (2*wnig*Lg)-Rg;
kp_iqg = kp_idg; 
ki_idg = (wnig^2)*Lg;
ki_iqg = ki_idg;

kp_v = -1000;
ki_v = -300000; %ki_v = -300000;


Rcrowbar = 0.2; % crowbar circuit resistance
Tcrowbar = 0.1; % crowbar duration 0.1s

t_dip= 30;
t_recover = 35;
t_normal = 417;

% t_dip= 3;
% t_recover = 3.5;
% t_normal = 4.17;

num_r = [2*wni-Rr/(sigma*Lr), wni^2];
den_r = [1, 2*wni, wni^2];

num_g = [2*wnig-Rg/Lg, wnig^2];
den_g = [1, 2*wnig, wnig^2];

% bode(num_g,den_g)
% hold on 
% bode(num_r,den_r)

% wnig2 = 60*2*pi;
% num_g2 = [2*wnig2-Rg/Lg, wnig2^2];
% den_g2 = [1, 2*wnig2, wnig2^2];
% step(num_g,den_g)
% hold on 
% step(num_g2,den_g2)
% figure(2)
% bode(num_g,den_g)
% hold on 
% bode(num_g2,den_g2)