MATLAB Scripts - Examples with Electrical Engineering Applications

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This lecture we will practice some Basic MATLAB Scripts.
›We will start with simple scripts and will discuss some electrical engineering applications.

Program to calculate Electricity bill.

w = input('Enter power of your device (in watts): ');
h = input('Enter time (in hours): ');
r = input('Enter electricity rate (in dollars per KWH): ');
ec = w * h/1000 * r;
disp(’Your Electricity bill is’)
Disp(ec)

Power transfer vs Load resistance curve

RL = 1:0.01:10;
Vs = 12;
Rs = 2.5;
P = (Vs^2*RL)./(RL+Rs).^2;
plot(RL,P)
xlabel('Load resistance')
ylabel('Power dissipated')

Torque-Speed Curve for a squirrel cage Induction Motor 

›Ns=1500; % Synchronous speed;
›R1=15.6 ;R2=14;X1=18; X2=23;Xm=260;Vt=400/sqrt(3);
›s = 0.002:0.002:1; % vector of slip
›N = Ns.*(1-s); % Speed, in RPM
›Ws = 2*pi*Ns/60; % Synchronous speed in rad/sec
›Rr = R2./ s; % Rotor resistance
›Zr = j*X2 + Rr; % Total rotor impedance
›Za = j*Xm*Zr./(j*Xm+Zr); % Air-gap impedance
›Zt = R1 + j*X1 +Za; % Terminal impedance
›Ia = Vt ./ Zt; % Terminal Current
›I2 = j*Xm*Ia./(j*Xm+Zr); % Rotor Current
›Pag = 3* (abs(I2)).^2.*Rr; % Air-Gap Power
›Pm = Pag.* (1-s); % Converted Power
›Trq = Pag/ Ws; % Developed Torque
›subplot(2,1,1)
›plot(N, Trq)
›xlabel('Speed in RPM')
›ylabel('Torque (Nm)')
›subplot(2,1,2)
›plot(Ia, Trq)
›xlabel('Load Current')
›ylabel('Torque (Nm)')

MATLAB Scripts - Examples from Shameer Ahmed Koya