第四周仿真及学习心得

Posted 2020-06-26

第四周作业

机卓1301储景瑞

一、设计任务：

结合本周学习的交流电机原理及启动、调速、制动特性，用Modelica设计和仿真一个用三相交流异步电机带动起重机起升机构运行。具体要求如下：

1）实现如下机械运动周期：

控制电机带重物上升，从静止加速到800r/min

保持800r/min匀速运动0.5s，

减速到静止，保持静止状态0.5s，

带重物下降，从静止达到600r/min

保持600r/min匀速运动0.6s，

减速到静止。
(为了便于仿真，匀速和静止持续时间较短)

2) 升降机构和重物折算到到电机转子轴上的等效负载惯量为1Kg.m^2，折算到到电机转子轴上的等效负载转矩是15N.m。

3）使用统一的电机模型,如果控制策略中用到转子串电阻，允许将该电机的转子改为绕线式转子（参数不变）。

4）参照教材中给出的交流电机启动、调速和制动方法，设计控制策略，用Modelica实现控制策略并与电机模型实现联合仿真。

5）可以采用定子串电阻、转子串电阻、定子调压、定子调频等手段，但必须具备工程上的可实施性。

6）评价指标：快速启动、制动，冲击转矩和冲击电流小，能耗小，兼顾实施的经济性。

7）方案最佳同学获本周"控制之星"称号。

二、理论推导

三、仿真结果

由仿真结果可以看出，该方案满足题目要求，时间也很短

四、学习心得

三相交流电机的计算还是比较麻烦的，不过套用书上的公式也不是很麻烦，但是要真正从其本质上理解它还是有点难度的，至少到现在我只有一个定性的理解，但是相信认真推导，与直流电机做类比，最后是可以理解的。同时还是很佩服特斯拉的，我想他也是掌握了最小作用原理的，我的理解是最小作用的都是对称的，还有很多极值点也都是在对称位置，但是一时也找不到具体的例子。

五、源代码

 

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";

parameter Resistance Rs = 0.531"Stator Resistance";

parameter Resistance Rr=8 "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 = 50"Rated Frequency of Stator";

parameter Voltage u_N = 220"Rated Phase Voltage of Stator";

parameter Real p =2"number of pole pairs";

parameter Inertia Jm = 0.1"Motor Inertia";

parameter Inertia Jl = 1"Load Inertia";

 

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 + 1000 * der(Psi_A);

u_B = Rs * i_B + 1000 * der(Psi_B);

u_C = Rs * i_C + 1000 * der(Psi_C);

 

0 = Rr * i_a + 1000 * der(Psi_a);

0 = Rr* i_b + 1000 * der(Psi_b);

0 = Rr * i_c + 1000 * 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 = 1000 * der(phi_m);

phi_m = phi/3;

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

 

Tm-Tl = (Jm+Jl) * 1000 * der(w);

 

 

if time <= 10 then

u_A = 0;

u_B = 0;

u_C = 0;

f_s = 0;

Tl = 0;

else if time<=1050 then

f_s = f_N;

u_A = u_N *1.732* 1.414 * sin(2*Pi*f_s*time/1000);

u_B = u_N *1.732* 1.414 * sin(2*Pi*f_s*time/1000-2*Pi/3);

u_C = u_N *1.732* 1.414 * sin(2*Pi*f_s*time/1000-4*Pi/3);

Tl =15;

else if time <=1550 then

f_s = f_N;

u_A = u_N * 1.414 * sin(2*Pi*f_s*time/1000);

u_B = u_N * 1.414 * sin(2*Pi*f_s*time/1000-2*Pi/3);

u_C = u_N * 1.414 * sin(2*Pi*f_s*time/1000-4*Pi/3);

Tl =15;

else if time <=1875 then

f_s = f_N;

u_A = u_N *1.732* 1.414 * sin(2*Pi*f_s*time/1000);

u_B = u_N *1.732* 1.414 * sin(2*Pi*f_s*time/1000-4*Pi/3);

u_C = u_N *1.732* 1.414 * sin(2*Pi*f_s*time/1000-2*Pi/3);

Tl =15;

else if time <=2375 then

u_A = 0;

u_B = 0;

u_C = 0;

f_s = 0;

Tl = 0;

else if time <=2825 then

f_s = f_N;

u_A = u_N *1.732* 1.414 * sin(2*Pi*f_s*time/1000);

u_B = u_N *1.732* 1.414 * sin(2*Pi*f_s*time/1000-4*Pi/3);

u_C = u_N *1.732* 1.414 * sin(2*Pi*f_s*time/1000-2*Pi/3);

Tl =15;

else if time <=3450 then

f_s = f_N*6/11;

u_A = u_N * 1.414 * sin(2*Pi*f_s*time/1000);

u_B = u_N * 1.414 * sin(2*Pi*f_s*time/1000-4*Pi/3);

u_C = u_N * 1.414 * sin(2*Pi*f_s*time/1000-2*Pi/3);

Tl =15;

else if time <=3700 then

f_s = f_N;

u_A = u_N * 1.414 * sin(2*Pi*f_s*time/1000);

u_B = u_N * 1.414 * sin(2*Pi*f_s*time/1000-2*Pi/3);

u_C = u_N * 1.414 * sin(2*Pi*f_s*time/1000-4*Pi/3);

Tl =15;

else if time <=3895 then

f_s = f_N;

u_A = u_N *1.732* 1.414 * sin(2*Pi*f_s*time/1000);

u_B = u_N * 1.732*1.414 * sin(2*Pi*f_s*time/1000-2*Pi/3);

u_C = u_N *1.732* 1.414 * sin(2*Pi*f_s*time/1000-4*Pi/3);

Tl =15;

else

u_A = 0;

u_B = 0;

u_C = 0;

f_s = 0;

Tl = 0;

end if;

end if ;

end if;

end if;

end if;

end if;

end if;

end if;

end if;

end SACIM;

 

simulate(SACIM,startTime=0,stopTime=6000)

 

plot(n)

 

plot(i_A)

 

plot(i_a)