د علي جعفر مهدي الحسيني

% M-file, t orque_speed_curve.m

% M-file c reate a p l o t o f the t orque-speed c urve o f the

% ind u c tion mo t or o f Exampl e 7 - 5.

% Fir s t , initia lize the va lues needed in thi s program.

rl = 0.641; % Stat o r res i s tance

xl = 1.10 6; % Stat o r r eactance

r2 = 0.332; % Rotor r es i s tance

x2 = 0.464,

xm = 26.3,

v-ph ase = 460 / sqrt (3) ,

n_sync = 1800,

w_sync = 188.5;

% Ca l c ulate the Thevenin

% 7 - 41a a n d 7 - 43.

v_th 0 v-ph ase • ( = I

% Rotor r eactance

% Magne tizati on bran ch r eactance

% Phase voltage

% Syn chro n ou s speed ( r / min )

% Sy n chro n ou s speed (rad /s)

vo ltage and impedance from Equat i ons

sqrt (rl "2 • (xl • xm )" 2 ) I ; , " 0 ( ( j*xm ) • (d • - j*xl ) ) I (r1 • j * (xl • xm ) ) ,

r -" 0 real ( z_ th ) ,

x -" 0 imag ( z_ th ) ,

~ Now ca l c ulate the t orqu e - speed chara c teri s ti c f or many

~ s lips between 0 and 1. Not e that the fir s t s lip value

~ i s set t o 0.001 ins tead of exact l y 0 to avoi d d i v i de~

by-zero probl ems.

s = (0 ,1,50 ) / 50;

s( l ) = 0 . 001;

% Slip

run = (1 - s) * n_sync; % Mech a ni cal speed

~ Ca l c ulate t orque f or original rotor r es i s tance

f or ii = 1,51

t _ indl (U ) = (3 * v_th" 2 * r2 / s (U )) / ...

(w_sync * (( r _th + r2 / s (ii )) "2 + (x_th + x2 ) " 2 ) ) ;

ond

~ Ca l c ulate t orque f or doubl ed roto r r es i s tance

f or ii = 1,51

t _ ind2 (U ) = (3 * v_th" 2 * (2*r2 ) / s( U )) / ...

(w_sync " (( r _th + (2*r2 )/s( U ))"2 + (x_th + x2 )" 2 ) ) ;

ond

~ Plo t the t orque-speed c urve

p l o t (run , t _ indl, ' Co l o r' , 'k' , 'LineWi dth ' ,2 . 0);

h o l d on;

p l o t (nm , t _ ind2, ' Co l or', 'k' , 'LineWi dth ' ,2.0, 'LineStyl e ' , '-. ' ) ;

x l abe l ( ' \ itn_( m)' , 'Pontwei ght' , 'Bo l d ' ) ;

y l abe l ( ' \ tau_( ind) ' , 'Pontwei ght' , 'Bo l d ' ) ;

title ( 'Ind uc tion mo t o r t orque-speed c harac teri s ti c ' , ...

'Pontwe i ght' , 'Bo l d ' ) ;

l egend ( ' Original R_(2) ' , 'Doubled R_(2} ' ) ;

gri d on;

h o l d o ff ;