Study notes the second of the fourth week

Simulation Jobs

For the AC motor model given by the teacher, the rotational speed of the rotating magnetic field during normal operation

N0=60f/p=1500r/min

In general, three-phase asynchronous motor rated speed nn= (0.94~0.985) N0, run the teacher gave the motor model, know that the rated speed of the motor is about 1490r/min

1. Selection of startup methods

The overall requirement is to have a large starting torque in the case of a small current.

Reference P70 The comparison of several common starting methods shows that, under the same starting current, the starting torque of the buck start of the self-coupling transformer is larger. The Y-buck start-up also has good start-up characteristics, but considering the variable K value of the buck start of the self-coupling transformer, the selectivity is more, it is advantageous for the back adjustment, so the self-coupling transformer buck start is chosen.

Select k=0.8

2. Selection of Speed regulation method

Requirements to meet the corresponding speed regulation.

The use of variable frequency speed control, because of its wide speed range, and can ensure the mechanical characteristics of the motor, the hardness of the n=0 when there is a large starting torque, conducive to start.

The value of the specific frequency ratio is to be obtained by debugging.

3. Choice of braking method

According to test instructions, the braking effect of the reverse-pull braking will be better than the energy-saving braking, the use of reverse-pull braking, but at the same time, the reverse braking can not automatically stop when the n=0, so need to control in time.

The starting stage is t=100-110ms,t=310ms when the rotational speed is stable at 800r/min

Uniform motion 0.5s, from t=310ms to t=810ms

Starting at 810ms, pull the brake to a speed of 0. Remain stationary from t=1000ms to t=1500ms.

Reverse acceleration starting from t=1500ms, t=1750ms speed stabilized at 600r/min

Uniform motion 0.6s, from t=1650ms to t=2250ms

Starting from 2250ms braking, to 2570ms braking to standstill.

The entire process takes 2570ms, while the torque TM is always controlled below 200.

The code is as follows:

Model SACIM "A simple AC induction motor Model"

Type Voltage=real (unit= "V");

Type Current=real (unit= "A");

Type Resistance=real (unit= "Ohm");

Type Inductance=real (unit= "H");

Type Speed=real (unit= "r/min");

Type Torque=real (unit= "n.m");

Type Inertia=real (unit= "kg.m^2");

Type Frequency=real (unit= "Hz");

Type Flux=real (unit= "Wb");

Type Angle=real (unit= "rad");

Type Angularvelocity=real (unit= "rad/s");

Constant Real Pi = 3.1415926;

Current I_a "A Phase Current of stator";

Current I_b "B Phase Current of stator";

Current I_c "C Phase Current of stator";

Voltage u_a "A Phase Voltage of Stator";

Voltage u_b "B Phase Voltage of Stator";

Voltage u_c "C Phase Voltage of Stator";

Current I_a "A Phase current of Rotor";

Current I_b "B Phase Current of Rotor";

Current I_c "C Phase Current of Rotor";

Frequency f_s "Frequency of Stator";

Torque Tm "Torque of the Motor";

Speed n ' Speed of the ' motor ';

Flux psi_a "A Phase flux-linkage of Stator";

Flux psi_b "B Phase flux-linkage of Stator";

Flux psi_c "C Phase flux-linkage of Stator";

Flux psi_a "A Phase flux-linkage of Rotor";

Flux Psi_b "b Phase flux-linkage of Rotor";

Flux Psi_c "C Phase flux-linkage of Rotor";

Angle Phi "Electrical Angle of Rotor";

Angle phi_m "mechnical Angle of Rotor";

angularvelocity W "Angular Velocity of Rotor";

Torque Tl "Load Torque";

Resistance Rs "stator resistance";

Parameter resistance rr=0.408 "Rotor resistance";

Parameter inductance Ls = 0.00252 "stator leakage inductance";

Parameter inductance Lr = 0.00252 "Rotor leakage inductance";

Parameter inductance Lm = 0.00847 "Mutual inductance";

Parameter Frequency f_n = "Rated Frequency of stator";

Parameter Voltage u_n = "Rated Phase Voltage of stator";

Parameter Real P =2 "Number of pole pairs";

Parameter Inertia Jm = 0.1 "motor inertia";

Parameter Inertia Jl = 0.1 "Load inertia";

Parameter Real k=0.8 "starting rate";

Parameter Real a=0.54 "frequency rate";

Parameter Real b=0.0546 "stable frequency rate";

Parameter Real c=0.3948 "another frequency rate";

Parameter Real p=0.7 "stoping rate";

Initial equation

psi_a = 0;

Psi_b = 0;

Psi_c = 0;

psi_a = 0;

Psi_b = 0;

Psi_c = 0;

phi = 0;

w = 0;

Equation

u_a = Rs * i_a + $ * der (psi_a);

U_b = Rs * i_b + $ * der (Psi_b);

U_c = Rs * I_c + $ * der (Psi_c);

0 = Rr * i_a + $ * der (psi_a);

0 = Rr * i_b + $ * der (Psi_b);

0 = Rr * i_c + $ * der (Psi_c);

Psi_a = (lm+ls) *i_a + ( -0.5*LM) *i_b + ( -0.5*LM) *i_c + (Lm*cos (phi)) *i_a + (Lm*cos (PHI+2*PI/3)) *i_b + (Lm*cos (PHI-2*PI/3)) * I_c;

Psi_b = ( -0.5*LM) *i_a + (Lm+ls) *i_b + ( -0.5*LM) *i_c + (Lm*cos (PHI-2*PI/3)) *i_a + (Lm*cos (phi)) *i_b + (Lm*cos (PHI+2*PI/3)) * I_c;

Psi_c = ( -0.5*LM) *i_a + ( -0.5*LM) *i_b + (Lm+ls) *i_c + (Lm*cos (PHI+2*PI/3)) *i_a + (Lm*cos (PHI-2*PI/3)) *i_b + (Lm*cos (PHI)) * I_c;

Psi_a = (Lm*cos (phi)) *i_a + (Lm*cos (PHI-2*PI/3)) *i_b + (Lm*cos (PHI+2*PI/3)) *i_c + (LM+LR) *i_a + ( -0.5*LM) *i_b + ( -0.5*Lm) * I_c;

Psi_b = (Lm*cos (PHI+2*PI/3)) *i_a + (Lm*cos (phi)) *i_b + (Lm*cos (PHI-2*PI/3)) *i_c + ( -0.5*LM) *i_a + (LM+LR) *i_b + ( -0.5*Lm) * I_c;

Psi_c = (Lm*cos (PHI-2*PI/3)) *i_a + (Lm*cos (PHI+2*PI/3)) *i_b + (Lm*cos (phi)) *i_c + ( -0.5*LM) *i_a + ( -0.5*LM) *i_b + (Lm+Lr) * I_c;

Tm =-p*lm* ((i_a*i_a+i_b*i_b+i_c*i_c) *sin (PHI) + (i_a*i_b+i_b*i_c+i_c*i_a) *sin (PHI+2*PI/3) + (i_a*i_c+i_b*i_a+i_c*i_ b) *sin (PHI-2*PI/3));

w = * der (phi_m);

Phi_m = phi/p;

n= w*60/(2*PI);

TM-TL = (JM+JL) * + * der (W);

Tl = 10;

If time <=

f_s = 0;

Rs = 0.531;

u_a = 0;

U_b = 0;

U_c = 0;

ElseIf time<=110 Then

f_s = F_n*a;

Rs = 0.531;

u_a = u_n * 1.414 * sin (2*pi*f_s*time/1000) *k*a;

U_b = u_n * 1.414 * sin (2*PI*F_S*TIME/1000-2*PI/3) *k*a;

U_c = u_n * 1.414 * sin (2*PI*F_S*TIME/1000-4*PI/3) *k*a;

ElseIf time<=810 Then

f_s = F_n*a;

Rs = 0.531;

u_a = u_n * 1.414 * sin (2*pi*f_s*time/1000) *a;

U_b = u_n * 1.414 * sin (2*PI*F_S*TIME/1000-2*PI/3) *a;

U_c = u_n * 1.414 * sin (2*PI*F_S*TIME/1000-4*PI/3) *a;

ElseIf time<=844 Then

f_s = F_n*a; Rs = 2.5;

u_a = u_n * 1.414 * sin (2*PI*F_S*TIME/1000-4*PI/3) *a;

U_b = u_n * 1.414 * sin (2*PI*F_S*TIME/1000-2*PI/3) *a;

U_c = u_n * 1.414 * sin (2*pi*f_s*time/1000) *a;

ElseIf time<=994 Then

f_s = F_n*a; Rs = 0.531;

u_a = u_n * 1.414 * sin (2*PI*F_S*TIME/1000-4*PI/3) *a;

U_b = u_n * 1.414 * sin (2*PI*F_S*TIME/1000-2*PI/3) *a;

U_c = u_n * 1.414 * sin (2*pi*f_s*time/1000) *a;

ElseIf time<=1495 Then

u_a = u_n * 1.414 * sin (2*pi*f_s*time/1000) *b;

U_b = u_n * 1.414 * sin (2*PI*F_S*TIME/1000-2*PI/3) *b;

U_c = u_n * 1.414 * sin (2*PI*F_S*TIME/1000-4*PI/3) *b;

f_s = f_n*b; Rs = 0.531;

ElseIf time<=1520 Then

u_a = u_n * 1.414 * sin (2*PI*F_S*TIME/1000-4*PI/3) *k*c;

U_b = u_n * 1.414 * sin (2*PI*F_S*TIME/1000-2*PI/3) *k*c;

U_c = u_n * 1.414 * sin (2*pi*f_s*time/1000) *k*c;

f_s = F_n*k*c; Rs = 0.531;

ElseIf time<=2250 Then

u_a = u_n * 1.414 * sin (2*PI*F_S*TIME/1000-4*PI/3) *c;

U_b = u_n * 1.414 * sin (2*PI*F_S*TIME/1000-2*PI/3) *c;

U_c = u_n * 1.414 * sin (2*pi*f_s*time/1000) *c;

f_s = F_n*c; Rs = 0.531;

ElseIf time<=2325 Then

f_s = F_n*p*a; Rs = 2;

u_a = u_n * 1.414 * sin (2*pi*f_s*time/1000) *a*p;

U_b = u_n * 1.414 * sin (2*PI*F_S*TIME/1000-2*PI/3) *a*p;

U_c = u_n * 1.414 * sin (2*PI*F_S*TIME/1000-4*PI/3) *a*p;

ElseIf time<=2465 Then

f_s = F_n*a; Rs = 0.531;

u_a = u_n * 1.414 * sin (2*pi*f_s*time/1000) *a;

U_b = u_n * 1.414 * sin (2*PI*F_S*TIME/1000-2*PI/3) *a;

U_c = u_n * 1.414 * sin (2*PI*F_S*TIME/1000-4*PI/3) *a;

Else

u_a = u_n * 1.414 * sin (2*pi*f_s*time/1000) *b;

U_b = u_n * 1.414 * sin (2*PI*F_S*TIME/1000-2*PI/3) *b;

U_c = u_n * 1.414 * sin (2*PI*F_S*TIME/1000-4*PI/3) *b;

f_s = f_n*b; Rs = 0.531;

End If;

End SACIM;

The image is as follows:

The entire process takes 2570ms, while the torque TM is always controlled below 200.

Study notes the second of the fourth week