matlab电机学重难点仿真

1、电机学难重点的MATLAB仿真实验报告铁磁材料磁化曲线的拟合一、实验内容及目的1.实验目的（1）了解磁化曲线的非线性和饱和特性。（2）掌握采用MATLAB进行曲线拟合的方法。2.基本知识在非铁磁材料中，磁通密度B和磁场强度H之间是线性关系，其系数就是空气的磁导率。而在铁磁材料中，二者是非线性关系，称为磁化曲线。一段典型的磁化曲线如图1所示。一般的，磁化曲线都有开始阶段，线性增长阶段，拐弯阶段和饱和阶段四部分，其中线性增长阶段和拐弯阶段的交界点就是曲线的膝点。图1 变压器磁化曲线由于表征磁化曲线是用磁通密度B和磁场强度H两维数组表示的，是不连续的，而且其变化特征也比较复杂。当数据量很大的时候采用

2、这种数组形式很不方便，也占用存储量，最好的处理方式，是采用曲线拟合方法，把磁化曲线表示成显函数形式的解析表达式。二、实验要求及要点描述 （1）采用屏幕图形方式直观显示磁化曲线。 （2）利用编程方法和MATLAB的拟合函数。 （3）根据所提供的数据，合理选取全部和部分数据绘制磁化曲线，并进行比较，不少于4条曲线。（4）绘制每条磁化曲线对应的图和表。（5）在一个图中显示全部曲线，并进行区分。三、基本知识及实验方法描述 （1）利用编程方法和MATLAB的拟合函数进行曲线拟合。 （2）由于磁感应强度B与电动势E之间是呈线性关系的，而磁场强度H和电流I之间也是呈线性关系的，所以在绘制磁化曲线时可以用E-

3、I曲线来表示B-H曲线，作为磁化曲线。（3）实验中利用多项式函数来进行曲线的拟合，在MATLAB中的拟合函数为p=polyfit(H1,B1,n); poly2str(p,'x'); z=polyval(p,H1);，分别选择全部数据或者部分数据进行拟合，先将数据选择好，然后再确定用几次多项式进行拟合，分别在一个图中显示四组数据拟合的曲线，更换拟合函数的多项式次数在进行实验，然后分析实验结果。四、实验源程序四张表的数据都进行13次拟合>> H1=1.401.431.461.491.521.551.581.611.641.67.1.711.751.791.831.87

4、1.911.951.992.032.07.2.122.172.222.272.322.372.422.482.542.60.2.672.742.812.882.953.023.093.163.243.32.3.403.483.563.643.723.803.893.984.074.16.4.254.354.454.554.654.764.885.005.125.24.5.365.495.625.755.886.026.166.306.456.60.6.756.917.087.267.457.657.868.088.318.55.8.809.069.339.619.9010.210.510.91

5、1.211.6.12.012.513.013.514.014.515.015.616.216.8.17.418.218.919.820.621.622.623.825.026.4.28.029.731.533.736.038.541.344.047.050.0.52.955.959.062.165.369.272.876.680.484.2.88.092.095.6100.0105.0110.0115.0120.0126.0132.0.138.0145.0152.0166.0173.0181.0189.0197.0205.0;>> B1=0.4:0.01:1.89a=polyfit

6、(h1,b1,13)for n=1:151hf1(n)=173*(n-1)/150bf1(n)=a(1)*hf1(n)13+a(2)*hf1(n)12+a(3)*hf1(n)11+a(4)*hf1(n)10+a(5)*hf1(n)9+a(6)*hf1(n)8+a(7)*hf1(n)7+a(8)*hf1(n)6+a(9)*hf1(n)5+a(10)*hf1(n)4+a(11)*hf1(n)3+a(12)*hf1(n)2+a(13)*hf1(n)1+a(14)endplot(hf1,bf1,'k')hold on %选取全部数据绘制D21磁化曲线xlabel('H(A/cm

7、)') %标注x，y轴ylabel('B(T)')h2=0.700.720.730.750.760.780.800.810.830.84 0.860.880.890.910.920.940.960.970.991.00 1.021.041.061.071.091.111.131.151.161.18 1.201.221.241.251.271.291.311.331.341.36 1.381.401.421.441.461.481.501.531.551.57 1.601.631.651.681.711.741.771.801.831.87 1.901.941.982.

8、022.062.112.162.222.272.33 2.402.472.542.622.702.792.882.973.063.16 3.263.373.483.593.713.833.974.114.264.41 4.564.734.915.105.305.515.735.966.216.46 6.737.017.317.627.948.278.628.999.379.76 10.1710.6011.0411.4911.9612.4512.9513.4613.9914.54 15.1015.6816.2816.9017.5418.2018.9019.6620.4721.34 22.2623

9、.2624.3825.6227.0028.5330.1331.7533.4035.07 36.8038.6040.4042.2044.0045.8047.7049.6051.5053.40b2=0.4:0.01:1.89a=polyfit(h2,b2,13)for n=1:151hf2(n)=53.4*(n-1)/150bf2(n)=a(1)*hf2(n)13+a(2)*hf2(n)12+a(3)*hf2(n)11+a(4)*hf2(n)10+a(5)*hf2(n)9+a(6)*hf2(n)8+a(7)*hf2(n)7+a(8)*hf2(n)6+a(9)*hf2(n)5+a(10)*hf2(n

10、)4+a(11)*hf2(n)3+a(12)*hf2(n)2+a(13)*hf2(n)1+a(14)endplot(hf2,bf2,'g')hold on %选取全部数据绘制D22磁化曲线>> h3=1.381.401.421.441.461.481.51.521.541.56 1.581.601.621.641.661.691.711.741.61.78 1.811.821.831.891.911.941.972.002.032.06 2.102.132.162.202.242.282.322.36242.45 2.502.552.602.652.71.762.8

11、12.872.932.99 3.063.133.196.63.333.413.493.573.653.74 3.833.924.014.114.224.334.444.564.674.8 4.935.075.215.365.525.685.846.006.166.33 6.526.726.947.167.387.627.868.108.368.62 8.909.209.509.8010.110.510.911.3611.712.1 12.613.113.614.214.815.516.317.118.119.1 20.121.222.423.725.026.728.530.432.635.1

12、37.840.743.746.850.053.456.860.464.067.8 72.076.480.885.490.295.0100105110116 122128134140146152158165172180b3=0.4:0.01:1.89len3=length(h3)hmax3=h3(len3)a=polyfit(h3,b3,13)for n=1:151hf3(n)=180*(n-1)/150bf3(n)=a(1)*hf3(n)13+a(2)*hf3(n)12+a(3)*hf3(n)11+a(4)*hf3(n)10+a(5)*hf3(n)9+a(6)*hf3(n)8+a(7)*hf3

13、(n)7+a(8)*hf3(n)6+a(9)*hf3(n)5+a(10)*hf3(n)4+a(11)*hf3(n)3+a(12)*hf3(n)2+a(13)*hf3(n)1+a(14)endplot(hf3,bf3,'m')hold on %选取全部数据绘制D23磁化曲线h4=1.371.381.41.421.441.461.481.501.521.54 1.561.581.61.621.641.661.681.701.721.75 1.771.791.811.841.871.891.921.941.972.00 2.032.062.092.122.162.202.232.27

14、2.312.35 2.392.432.482.522.572.622.672.732.792.85 2.912.973.033.13.173.243.313.393.473.55 3.633.713.793.883.974.064.164.264.374.48 4.604.724.865.005.145.295.445.605.765.92 6.106.286.466.656.857.57.257.467.687.90 5.148.408.388.969.269.589.8610.210.611.0 11.411.812.612.813.313.814.415.015.716.4 17.218

15、.018.919.920.922.123.525.026.828.6 30.733.035.638.241.144.047.050.053.557.5 61.566.070.57579.784.589.594.7100105 110116122128134141148155162170b4=0.4:0.01:1.89a=polyfit(h4,b4,13)for n=1:151hf4(n)=170*(n-1)/150bf4(n)=a(1)*hf4(n)13+a(2)*hf4(n)12+a(3)*hf4(n)11+a(4)*hf4(n)10+a(5)*hf4(n)9+a(6)*hf4(n)8+a(

16、7)*hf4(n)7+a(8)*hf4(n)6+a(9)*hf4(n)5+a(10)*hf4(n)4+a(11)*hf4(n)3+a(12)*hf4(n)2+a(13)*hf4(n)1+a(14)endplot(hf4,bf4,'b') %选取全部数据绘制D24磁化曲线 五、实验结果（1）硅钢片D21磁化曲线图和表A/cm00.010.020.030.040.050.060.070.080.090.41.41.431.461.491.521.551.581.611.641.670.51.711.751.791.831.871.911.951.992.032.070.62.122

17、.172.222.272.322.372.422.482.542.600.72.672.742.812.882.953.023.093.163.243.320.83.403.483.563.643.723.803.893.984.074.160.94.254.354.454.554.654.764.885.005.125.241.05.365.495.625.755.886.026.166.306.456.601.16.756.917.087.267.457.657.868.088.318.551.28.809.069.339.619.9010.210.510.911.211.61.312.0

18、12.513.013.514.014.515.015.616.216.81.417.418.218.919.820.621.622.623.825.026.41.528.029.731.533.736.038.541.344.047.050.01.652.955.959.062.165.369.272.876.680.484.21.788.092.095.61001051101151201261321.8138145152195166173181189197205（2）硅钢片D22磁化曲线图和表 00.010.020.030.040.050.060.070.080.090.40.700.720

19、.730.750.760.780.800.810.830.840.50.860.880.890.910.920.940.960.970.991.000.61.021.041.061.071.091.111.131.151.161.180.71.201.221.241.251.271.291.311.331.341.360.81.381.401.421.441.461.481.501.531.551.570.91.601.631.651.681.711.741.771.801.831.871.01.901.941.982.022.062.112.162.222.272.331.12.402.47

20、2.542.622.702.792.882.973.063.161.23.263.373.483.593.713.833.974.114.264.411.34.564.734.915.105.305.515.735.966.216.461.46.737.017.317.627.948.278.628.999.379.761.510.1710.6011.0411.4911.9612.4512.9513.4613.9914.541.615.1015.6816.2816.9017.5418.2018.9019.6620.4721.341.722.2623.2624.3825.6227.0028.53

21、30.1331.7533.4035.071.836.8038.6040.4042.2044.0045.8047.7049.6051.5053.40（3）硅钢片D23磁化曲线图和表00.010.020.030.040.050.060.070.080.090.41.381.401.421.441.461.481.51.521.541.560.51.581.601.621.641.661.691.711.741.61.780.61.811.821.831.891.911.941.972.002.032.060.72.102.132.162.202.242.282.322.36242.450.82.5

22、02.552.602.652.71.762.812.872.932.990.93.063.133.196.63.333.413.493.573.653.741.03.833.924.014.114.224.334.444.564.674.81.14.935.075.215.365.525.685.846.006.166.331.26.526.726.947.167.387.627.868.108.368.621.38.909.209.509.8010.110.510.911.3611.712.11.412.613.113.614.214.815.516.317.118.119.11.520.1

23、21.222.423.725.026.728.530.432.635.11.637.840.743.746.850.053.456.860.464.067.81.772.076.480.885.490.295.01001051101161.8122128134140146152158165172180（4）硅钢片D24磁化曲线图和表A/cm00.010.020.030.040.050.060.070.080.090.41.371.381.41.421.441.461.481.501.521.540.51.561.581.61.621.641.661.681.701.721.750.61.771

24、.791.811.841.871.891.921.941.972.000.72.032.062.092.122.162.202.232.272.312.350.82.392.432.482.522.572.622.672.732.792.850.92.912.973.033.13.173.243.313.393.473.551.03.633.713.793.883.974.064.164.264.374.481.14.604.724.865.005.145.295.445.605.765.921.26.106.286.466.656.857.57.257.467.687.901.35.148.

25、408.388.969.269.589.8610.210.611.01.411.411.812.612.813.313.814.415.015.716.41.517.218.018.919.920.922.123.525.026.828.61.630.733.035.638.241.144.047.050.053.557.51.761.566.070.57579.784.589.594.71001051.8110116122128134141148155162170（5）四条磁化曲线在一个表中 3、实验结果的分析从拟合的磁化曲线我们可以看出，当磁场强度比较小时，磁通密度与磁场强度基本呈线性关系

26、，也称为起始阶段和线性增长阶段，随着H的逐渐增大，磁通密度趋向于饱和，当H增加到很大时，磁通密度基本保持不变，即进入了饱和阶段，可见，实验结果与理论分析基本一致。四种硅钢片由于工艺不同，对应的磁化曲线也有所不同，实际中可以根据需要进行选择。单相变压器的电压变化率曲线及效率曲线一、实验内容及目的1.了解变压器电压变化率的变化规律；2.了解负载性质对电压变化率特性的影响；3.了解变压器效率曲线的变化规律；4.了解负载特性对效率曲线的影响。二、实验要求及要点描述1.采用屏幕图形方式直观显示；2.画出对应阻性、感性、容性三种负载性质的特性曲线，且要通过额定点；3.画出对应不同负载功率因数的效率曲线，且

27、通过额定点；4.给出特征性的结论。三、基本知识变压器一次接额定电压，二次侧空载时的电压就是额定电压。当二次侧接入负载后，即使一次侧电压不变，二次侧的电压也不再是额定值，变化后的电压大小与负载电流、负载性质和短路阻抗参数有关。表征该变化的物理量就是电压变化率，根据电机学理论，电压变化率为：1.对于阻性负载，有；2.对于感性负载，有，而且数值比阻性的大，；3.对于容性负载，则可能出现；在所有种类电机中，变压器效率最高，而且高效工作区间很宽，一般效率在95%-99%之间。变压器的效率是指输出功率和输入功率之间的比值：根据上式，就可以求出对应不同的负载功率因数，当负载电流的标幺值在0,0.12区间内变

28、化时，变压器的效率曲线。四、实验源程序1.电压变化率曲线：clear;Rk=0.0093;Xk=0.04821;cos=0.85;sin=0.52678;I1=0:0.001:15.15;I2=0:0.001:1;dUz=I1*(Rk*cos+Xk*sin);dUn=I1*(Rk*1+Xk*0);dUq=I1*(Rk*cos-Xk*sin);U2z=1-dUz;U2n=1-dUn;U2q=1-dUq;plot(I1,U2z,'r',I1,U2n,'-.g',I1,U2q,'-b',I1,1,'k:');axis(0 1.2 0.5 1.2);title('变压器的外特性');ylabel('额定U_2 (%)');xlabel('额定I_2 (%)');text(0.81