A quick non technical post today but I wanted to leave a few words on a new Matlab blog from Mathworks which I think is going to be interesting. I take this opportunity to mention two other, well established and excellent, blogs, that I very often read.

Indeed, Cleve Moller, one of the founder of Matlab, has decided to start Blogging! Welcome in the blogging community, Cleve, I am excited to read your future posts!

He wrote a book that I highly recommend for beginners :

Numerical Computing with Matlab

Also from Mathworks. One of these blogs that you will inevitably end up reading if you have some technical issues in Matlab. Lots and lots of very good material. She also has some bits of her hidden in the source code.

This blog is from an independent blogger in Israel. Very very impressive work. Yair talks about undocumented aspects of Matlab. Sometimes, I wonder if he does not have secretely access to the source code.

He also made a book that is extremely useful when you seriously work with interfaces in Matlab :

Undocumented Secrets of MATLAB-Java Programming

Which Matlab blogs do you read often?

I have never used matlab before and am having a lot of trouble understanding how to do things. Ive been asked to write a script that opens a figure with x and y axis that run from -10 to 10, lets you click on the figure and plots the location that I have clicked with a red x. Any tips would help me out greatly thank you.

Hi Hunter,

There are a lot of ressources on this website to help you with that. I encourage you to start with the beginning and go through tutorials to learn Matlab. I know it is a little time consuming but definitely worth it in the end.

The Java aspect is a powerful tool. I am exploring this as well as dynamic user interfaces. Please visit:

http://franksmatlabtips.blogspot.com

Would love to hear from you.

I need help for my m file. Here it is. It’s :

% DFIG Parameters Rotor parameters reffered 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 = 1740; % rated stator current (A)

Tem = 12732; %Rated torqu (N.m)

p = 2; % Pole pair

u = 1/3; %stator/rotor turns ratio

Vr = 2070; %Rated rotor voltage reffered to stator

max = 1/3; % Maximum slip

Vr_stator = (Vr*max)*u; % Rated rotor voltage referred to stator

Rs = 2.4e-3; % Stator resistance (ohm)

Lsi = 0.067e-3; %Leakage inductance(rotor & stator)

Lm = 2.5e-3; %Magnetic Induction

Rr = 2.9e-3; % rotor resistance (ohm)

Ls = Lm + Lsi; % Stator inductance

Lr = Lm + Lsi; %Rotor inductance

Vbus = Vr_stator*sqrt(2); %Dc dc bus voltage referred to stator

sigma = 1 – Lm^2/(Ls*Lr);

Fs = Vs*sqrt(2/3)/(2*pi*f); % stator flux (approx)

J = 127/2; % inertia

D = 1e-3; %damping

fsw = 4e3; % swtitching frequency

Ts = 1/fsw/50; % sample time (sec)

% PI regulators

tau_i =(sigma*Lr)/Rr;

tau_n = 0.05;

wmi = 100*(1/tau_i);

wmn = 1/tau_n;

kp_id =(2*wmi*sigma*Lr)-Rr;

kp_iq = kp_id;

ki_id = (wmi^2)*Lr*sigma;

ki_iq = ki_id;

kp_n = (2*wmn*J)/p;

ki_n = (wmn^2*J)/p;

% three blades wind turbine model

N = 100; % gera box ratio

Radio = 42; % Radio

ro = 1.225; % Air density

% Cp and Ct curves

beta = 0; % pitch angle

ind2 = 2;

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 function of wind speed

P = 1.0e6 *[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)

when I run it . I get this error:

Error using plot

Vectors must be the same length.

Error in ini (line 67)

plot(tab_lambda,Ct,’linewidth’,1.5)