電磁場重難點(diǎn)的仿真

1、電機(jī)學(xué)難重點(diǎn)的MATLAB仿真實(shí)驗(yàn)報(bào)告一、實(shí)驗(yàn)內(nèi)容及目的(1.5分)（一）實(shí)驗(yàn)內(nèi)容1.磁性材料磁化曲線的繪制2.變壓器電壓變化率及效率曲線的繪制（二）實(shí)驗(yàn)?zāi)康?.了解磁性材料磁化曲線的非線性和飽和特性；2.掌握采用MATLAB進(jìn)行曲線擬合的方法；3.了解變壓器電壓變化率的變化規(guī)律；4.了解負(fù)載性質(zhì)對(duì)電壓變化率特性特性的影響；5.了解變壓器效率曲線的變化規(guī)律；6.了解負(fù)載性質(zhì)對(duì)效率曲線的影響。二、實(shí)驗(yàn)要求及要點(diǎn)描述(2.5分)（1）磁性材料磁化曲線的繪制給出的五種磁化材料的磁化數(shù)據(jù)如下：50Hz熱軋硅鋼片DR610-50(D21)磁化曲線A/cm00.010.020.030.040.050.06

2、0.070.080.090.41.41.431.461.491.521.551.581.611.641.670.51.711.751.791.831.871.911.951.992.032.070.62.122.172.222.272.322.372.422.482.542.600.72.672.742.812.882.953.023.093.163.243.320.83.403.483.563.643.723.803.893.984.074.160.94.254.354.454.554.654.764.885.005.125.241.05.365.495.625.755.886.026.16

3、6.306.456.601.16.756.917.087.267.457.657.868.088.318.551.28.809.069.339.619.9010.210.510.911.211.61.312.012.513.013.514.014.515.015.616.216.81.417.418.218.919.820.621.622.623.825.026.41.528.029.731.533.736.038.541.344.047.050.01.652.955.959.062.165.369.272.876.680.484.21.788.092.095.6100105110115120

4、1261321.813814515219516617318118919720550Hz熱軋硅鋼片DR530-50(D22)磁化曲線A/cm00.010.020.030.040.050.060.070.080.090.40.700.720.730.750.760.780.800.810.830.840.50.860.880.890.910.920.940.960.970.991.000.61.021.041.061.071.091.111.131.151.161.180.71.201.221.241.251.271.291.311.331.341.360.81.381.401.421.441.4

5、61.481.501.531.551.570.91.601.631.651.681.711.741.771.801.831.871.01.901.941.982.022.062.112.162.222.272.331.12.402.472.542.622.702.792.882.973.063.161.23.263.373.483.593.713.833.974.114.264.411.34.564.734.915.105.305.515.735.966.216.461.46.737.017.317.627.948.278.628.999.379.761.510.1710.6011.0411.

6、4911.9612.4512.9513.4613.9914.541.615.1015.6816.2816.9017.5418.2018.9019.6620.4721.341.722.2623.2624.3825.6227.0028.5330.1331.7533.4035.071.836.8038.6040.4042.2044.0045.8047.7049.6051.5053.4050Hz熱軋硅鋼片DR510-50(D23)磁化曲線A/cm00.010.020.030.040.050.060.070.080.090.41.381.401.421.441.461.481.51.521.541.56

7、0.51.581.601.621.641.661.691.711.741.61.780.61.811.821.831.891.911.941.972.002.032.060.72.102.132.162.202.242.282.322.36242.450.82.502.552.602.652.71.762.812.872.932.990.93.063.133.196.63.333.413.493.573.653.741.03.833.924.014.114.224.334.444.564.674.81.14.935.075.215.365.525.685.846.006.166.331.26.

8、526.726.947.167.387.627.868.108.368.621.38.909.209.509.8010.110.510.911.3611.712.11.412.613.113.614.214.815.516.317.118.119.11.520.121.222.423.725.026.728.530.432.635.11.637.840.743.746.850.053.456.860.464.067.81.772.076.480.885.490.295.01001051101161.812212813414014615215816517218050Hz熱軋硅鋼片DR490-50

9、(D24)磁化曲線A/cm00.010.020.030.040.050.060.070.080.090.41.371.381.41.421.441.461.481.501.521.540.51.561.581.61.621.641.661.681.701.721.750.61.771.791.811.841.871.891.921.941.972.000.72.032.062.092.122.162.202.232.272.312.350.82.392.432.482.522.572.622.672.732.792.850.92.912.973.033.13.173.243.313.393.4

10、73.551.03.633.713.793.883.974.064.164.264.374.481.14.604.724.865.005.145.295.445.605.765.921.26.106.286.466.656.857.57.257.467.687.901.35.148.408.388.969.269.589.8610.210.611.01.411.411.812.612.813.313.814.415.015.716.41.517.218.018.919.920.922.123.525.026.828.61.630.733.035.638.241.144.047.050.053.

11、557.51.761.566.070.57579.784.589.594.71001051.811011612212813414114815516217050Hz DW470-50冷軋硅鋼片磁化曲線A/cm00.010.020.030.040.050.060.070.080.090.50.650.660.670.680.690.700.710.720.730.740.60.750.760.760.770.780.790.800.810.820.830.70.840.850.860.870.880.890.910.930.940.950.80.96.970.981.001.021.051.61.

12、071.081.100.91.121.141.161.181.201.221.241.261.281.301.01.341.351.401.421.441.491.551.581.601.651.11.701.751.801.851.901.951.982.002.102.201.22.302.402.502.602.702.802.852.903.003.201.33.403.603.804.004.104.304.604.805.005.401.45.906.206.607.007.808.509.009.8010.0011.01.512.013.014.015.016.018.020.0

13、22.024.025.01.628.030.032.034.038.040.044.047.050.054.01.758.060.064.070.073.076.080.084.090.095.01.8100該部分實(shí)驗(yàn)要求如下：（1）繪制磁化曲線；（2）根據(jù)所提供的數(shù)據(jù)，合理選取全部和部分?jǐn)?shù)據(jù)繪制磁化曲線，并進(jìn)行比較，不少于4條曲線；（3）繪制每條磁化曲線對(duì)應(yīng)的圖和表；（4）在一個(gè)圖中顯示全部曲線，并進(jìn)行區(qū)分要點(diǎn)分析：（1）采用屏幕圖形方式直觀顯示；（2）利用編程方法和MATLAB的擬合函數(shù)；（3）利用多項(xiàng)式進(jìn)行擬合（2）變壓器電壓變化率及效率曲線的繪制有一臺(tái)單相1000KVA、66/6.6K

14、V的變壓器，實(shí)驗(yàn)數(shù)據(jù)如下：變壓器空載和短路實(shí)驗(yàn)數(shù)據(jù)實(shí)驗(yàn)名稱電壓（V）電流（A）功率（W）電源加載側(cè)空載66009.15400低壓側(cè)短路324015.159300高壓側(cè)要求對(duì)該變壓器進(jìn)行仿真，分別繪制出低壓側(cè)帶載參數(shù)為：超前，滯后，情況下的電壓變化率曲線和負(fù)載曲線。要點(diǎn)分析：(1)采用屏幕圖形方式直觀顯示；(2)利用MATLAB編程實(shí)現(xiàn)；(3)要畫出對(duì)應(yīng)的阻性、感性、容性三種負(fù)載性質(zhì)的特性曲線，并要通過額定點(diǎn)；（4）要畫出對(duì)應(yīng)不同的的效率曲線；(5)給出特征性的結(jié)論。三、基本知識(shí)及實(shí)驗(yàn)方法描述(3分)（一）在非鐵磁材料中，磁通密度B和磁場強(qiáng)度H之間是線性關(guān)系，其系數(shù)就是空氣的磁導(dǎo)率0。而在鐵磁材

15、料中，二者是非線性關(guān)系，稱為磁化曲線。一段典型的磁化曲線如下圖所示。一般的，磁化曲線都有開始階段、線性增長階段、拐彎階段和飽和階段四部分，其中線性增長階段和拐彎階段的交界點(diǎn)就是曲線的膝點(diǎn)。BH0鐵磁材料的磁化曲線由于表征磁化曲線是用磁通密度B和磁場強(qiáng)度H兩維數(shù)組表示的，是不連續(xù)的，而且其變化特征也比較復(fù)雜。當(dāng)數(shù)據(jù)很大的時(shí)候，采用這種數(shù)組形式很不方便，也占用儲(chǔ)存量。最好的處理方式，是采用曲線擬合方法，把磁化曲線表示成顯函數(shù)形式的解析表達(dá)式。（二）變壓器一次側(cè)接額定電壓，二次側(cè)空載時(shí)的電壓就是額定電壓。當(dāng)二次側(cè)接入負(fù)載后，即使一次側(cè)電壓不變，二次側(cè)電壓也不再是額定值，變化后的電壓大小與負(fù)載電流、負(fù)

16、載性質(zhì)和短路阻抗參數(shù)有關(guān)。表征該變化的物理量就是電壓變化率U。根據(jù)電機(jī)學(xué)理論，電壓變化率為：其中，負(fù)載電流的標(biāo)幺值；，短路電阻、短路電抗的標(biāo)幺值；負(fù)載的功率因數(shù)角根據(jù)上式，即使負(fù)載電流和變壓器短路參數(shù)不變，負(fù)載性質(zhì)發(fā)生改變，那么電壓變化率也會(huì)發(fā)生變化，進(jìn)而影響輸出電壓的大小。一般地，該變化規(guī)律為：（1） 對(duì)阻性負(fù)載，=0，必然有U>0, <1；（2） 對(duì)感性負(fù)載，>0，也必然有U>0,而且數(shù)值比阻性的要大， <1；（3） 對(duì)容性負(fù)載，<0，則可能出現(xiàn)U<0, >1；為了直觀，以變壓器的輸出外特性來表示電壓變化率的變化。（三）在所有種類的電機(jī)中，變

17、壓器的效率是最高的，而且高效率工作區(qū)間很寬。一般地，電力變壓器的效率都在95%99%之間。電機(jī)學(xué)中變壓器的效率表示為：式中，P0額定電壓時(shí)的空載損耗；PkN額定電流時(shí)的短路損耗；負(fù)載電流的標(biāo)幺值；SN變壓器的額定容量；cos負(fù)載的功率因數(shù)。根據(jù)上式，就可以求出對(duì)應(yīng)于不同的cos，當(dāng)負(fù)載電流的標(biāo)幺值在0,2區(qū)間內(nèi)變化時(shí)，變壓器的效率曲線了。四、實(shí)驗(yàn)源程序(1分)（一）磁化曲線的繪制clcclearHdata = 1.40,1.43,1.46,1.49,1.52,1.55,1.58,1.61,1.64,1.67, . 1.71,1.75,1.79,1.83,1.87,1.91,1.95,1.99,

18、2.03,2.07, . 2.12,2.17,2.22,2.27,2.32,2.37,2.42,2.48,2.54,2.60, . 2.67,2.74,2.81,2.88,2.95,3.02,3.09,3.16,3.24,3.32, . 3.40,3.48,3.56,3.64,3.72,3.80,3.89,3.98,4.07,4.16, . 4.25,4.35,4.45,4.55,4.65,4.76,4.88,5.00,5.12,5.24, . 5.36,5.49,5.62,5.75,5.88,6.02,6.16,6.30,6.45,6.60, . 6.75,6.91,7.08,7.26,7.

19、45,7.65,7.86,8.08,8.31,8.55, . 8.80,9.06,9.33,9.61,9.90,10.2,10.5,10.9,11.2, 11.6, . 12.0,12.5,13.0,13.5,14.0,14.5,15.0,15.6,16.2,16.8, . 17.4,18.2,18.9,19.8,20.6,21.6,22.6,23.8,25.0,26.4, . 28.0,29.7,31.5,33.7,36.0,38.5,41.3,44.0,47.0,50.0, . 52.9,55.9,59.0,62.1,65.3,69.2,72.8,76.6,80.4,84.2, . 88.

20、0,92.0,95.6,100, 105, 110, 115,120, 126, 132, . 138,145, 152, 195,166, 173, 181, 189, 197,205 ;Bdata=0.40:0.01:1.89;len=length(Hdata)Hmax=Hdata(len);a=polyfit(Hdata,Bdata,13);for n=1:151Hfit(n)=Hmax*(n-1)/150;Bfit(n)=a(1)*Hfit(n)13+a(2)*Hfit(n)12+a(3)*Hfit(n)11+a(4)*Hfit(n)10+a(5)*Hfit(n)9+a(6)*Hfit

21、(n)8+a(7)*Hfit(n)7+a(8)*Hfit(n)6+a(9)*Hfit(n)5+a(10)*Hfit(n)4+a(11)*Hfit(n)3+a(12)*Hfit(n)2+a(13)*Hfit(n)1+a(14);endplot(Hdata,Bdata,'*')holdplot(Hfit,Bfit)holdxlabel('HA/cm')ylabel('BT')1.繪制D21磁化曲線的源程序2繪制D22，D23和D24的源程序與繪制D21的磁化曲線源程序基本一致，只是輸入的數(shù)據(jù)Hdata不同，將給出數(shù)據(jù)輸入即可。在繪制DW470-50冷

22、軋硅鋼片磁化曲線時(shí)，除了輸入數(shù)據(jù)Hdata和Bdata不同，擬合的階數(shù)也做了相應(yīng)改變，變成12階擬合。3.在將所有曲線繪制于同一坐標(biāo)系時(shí)，為了便于觀察，沒有繪制出各個(gè)分散的點(diǎn)。clcclear%DW470-50冷軋硅鋼片磁化曲線數(shù)據(jù)Hdata= 0.65,0.66,0.67,0.68,0.69,0.70,0.71,0.72,0.73,0.74, .0.75,0.76,0.76,0.77,0.78,0.79,0.80,0.81,0.82,0.83, .0.84,0.85,0.86,0.87,0.88,0.89,0.91,0.93,0.94,0.95, .0.96,0.97,0.98,1.00,1

23、.02,1.05,1.6,1.07,1.08,1.10, .1.12,1.14,1.16,1.18,1.20,1.22,1.24,1.26,1.28,1.30, .1.34,1.35,1.40,1.42,1.44,1.49,1.55,1.58,1.60,1.65, .1.70,1.75,1.80,1.85,1.90,1.95,1.98,2.00,2.10,2.20, .2.30,2.40,2.50,2.60,2.70,2.80,2.85,2.90,3.00,3.20, .3.40,3.60,3.80,4.00,4.10,4.30,4.60,4.80,5.00,5.40, .5.90,6.20,

24、6.60,7.00,7.80,8.50,9.00,9.80,10.00,11.0, .12.0,13.0,14.0,15.0,16.0,18.0,20.0,22.0,24.0,25.0, .28.0,30.0,32.0,34.0,38.0,40.0,44.0,47.0,50.0,54.0, .58.0,60.0,64.0,70.0,73.0,76.0,80.0,84.0,90.0,95.0;Bdata=0.50:0.01:1.79;len=length(Hdata)Hmax=Hdata(len);a=polyfit(Hdata,Bdata,12);for n=1:131Hfit(n)=Hmax

25、*(n-1)/130;Bfit(n)=a(1)*Hfit(n)12+a(2)*Hfit(n)11+a(3)*Hfit(n)10+a(4)*Hfit(n)9+a(5)*Hfit(n)8+a(6)*Hfit(n)7+a(7)*Hfit(n)6+a(8)*Hfit(n)5+a(9)*Hfit(n)4 .+a(10)*Hfit(n)3+a(11)*Hfit(n)2+a(12)*Hfit(n)1+a(13);end%D21磁化曲線數(shù)據(jù)Hdata1 = 1.40,1.43,1.46,1.49,1.52,1.55,1.58,1.61,1.64,1.67, . 1.71,1.75,1.79,1.83,1.87

26、,1.91,1.95,1.99,2.03,2.07, . 2.12,2.17,2.22,2.27,2.32,2.37,2.42,2.48,2.54,2.60, . 2.67,2.74,2.81,2.88,2.95,3.02,3.09,3.16,3.24,3.32, . 3.40,3.48,3.56,3.64,3.72,3.80,3.89,3.98,4.07,4.16, . 4.25,4.35,4.45,4.55,4.65,4.76,4.88,5.00,5.12,5.24, . 5.36,5.49,5.62,5.75,5.88,6.02,6.16,6.30,6.45,6.60, . 6.75,6

27、.91,7.08,7.26,7.45,7.65,7.86,8.08,8.31,8.55, . 8.80,9.06,9.33,9.61,9.90,10.2,10.5,10.9,11.2, 11.6, . 12.0,12.5,13.0,13.5,14.0,14.5,15.0,15.6,16.2,16.8, . 17.4,18.2,18.9,19.8,20.6,21.6,22.6,23.8,25.0,26.4, . 28.0,29.7,31.5,33.7,36.0,38.5,41.3,44.0,47.0,50.0, . 52.9,55.9,59.0,62.1,65.3,69.2,72.8,76.6,

28、80.4,84.2, . 88.0,92.0,95.6,100, 105, 110, 115,120, 126, 132, . 138,145, 152, 195,166, 173, 181, 189, 197,205 ;總程序如下：Bdata1=0.40:0.01:1.89;len1=length(Hdata1)Hmax1=Hdata1(len1);a1=polyfit(Hdata1,Bdata1,13);for n=1:151Hfit1(n)=Hmax1*(n-1)/150;Bfit1(n)=a1(1)*Hfit1(n)13+a1(2)*Hfit1(n)12+a1(3)*Hfit1(n)1

29、1+a1(4)*Hfit1(n)10+a1(5)*Hfit1(n)9+a1(6)*Hfit1(n)8+a1(7)*Hfit1(n)7+a1(8)*Hfit1(n)6+a1(9)*Hfit1(n)5+a1(10)*Hfit1(n)4+a1(11)*Hfit1(n)3+a1(12)*Hfit1(n)2+a1(13)*Hfit1(n)1+a1(14);end%D22磁化曲線數(shù)據(jù)Hdata2 = 0.70, 0.72, 0.73, 0.75, 0.76, 0.78, 0.80, 0.81, 0.83, 0.84, .0.86, 0.88, 0.89, 0.91, 0.92, 0.94, 0.96, 0

30、.97, 0.99, 1.00, .1.02, 1.04, 1.06, 1.07, 1.09, 1.11, 1.13, 1.15, 1.16, 1.18, .1.20, 1.22, 1.24, 1.25, 1.27, 1.29, 1.31, 1.33, 1.34, 1.36, .1.38, 1.40, 1.42, 1.44, 1.46, 1.48, 1.50, 1.53, 1.55, 1.57, .1.60, 1.63, 1.65, 1.68, 1.71, 1.74, 1.77, 1.80, 1.83, 1.87, .1.90, 1.94, 1.98, 2.02, 2.06, 2.11, 2.

31、16, 2.22, 2.27, 2.33, .2.40, 2.47, 2.54, 2.62, 2.70, 2.79, 2.88, 2.97, 3.06, 3.16, .3.26, 3.37, 3.48, 3.59, 3.71, 3.83, 3.97, 4.11, 4.26, 4.41, .4.56, 4.73, 4.91, 5.10, 5.30, 5.51, 5.73, 5.96, 6.21, 6.46, .6.73, 7.01, 7.31, 7.62, 7.94, 8.27, 8.62, 8.99, 9.37, 9.76, .10.17, 10.60, 11.04, 11.49, 11.96

32、, 12.45, 12.95, 13.46, 13.99, 14.54, .15.10, 15.68, 16.28, 16.90, 17.54, 18.20, 18.90, 19.66, 20.47, 21.34, .22.26, 23.26, 24.38, 25.62, 27.00, 28.53, 30.13, 31.75, 33.40, 35.07, .36.80, 38.60, 40.40, 42.20, 44.00, 45.80, 47.70, 49.60, 51.50, 53.40;Bdata2=0.40:0.01:1.89;len2=length(Hdata2)Hmax2=Hdat

33、a2(len2);a2=polyfit(Hdata2,Bdata2,13);for n=1:151Hfit2(n)=Hmax2*(n-1)/150;Bfit2(n)=a2(1)*Hfit2(n)13+a2(2)*Hfit2(n)12+a2(3)*Hfit2(n)11+a2(4)*Hfit2(n)10+a2(5)*Hfit2(n)9+a2(6)*Hfit2(n)8+a2(7)*Hfit2(n)7+a2(8)*Hfit2(n)6+a2(9)*Hfit2(n)5+a2(10)*Hfit2(n)4+a2(11)*Hfit2(n)3+a2(12)*Hfit2(n)2+a2(13)*Hfit2(n)1+a

34、2(14);end%D23磁化曲線數(shù)據(jù)Hdata3 = 1.38, 1.40, 1.42, 1.44, 1.46, 1.48, 1.5, 1.52, 1.54, 1.56, .1.58, 1.60, 1.62, 1.64, 1.66, 1.69, 1.71, 1.74, 1.6, 1.78, .1.81, 1.82, 1.83, 1.89, 1.91, 1.94, 1.97, 2.00, 2.03, 2.06, .2.10, 2.13, 2.16, 2.20, 2.24, 2.28, 2.32, 2.36, 24, 2.45, .2.50, 2.55, 2.60, 2.65, 2.7, 1.7

35、6, 2.81, 2.87, 2.93, 2.99, .3.06, 3.13, 3.19, 6.6, 3.33, 3.41, 3.49, 3.57, 3.65, 3.74, .3.83, 3.92, 4.01, 4.11, 4.22, 4.33, 4.44, 4.56, 4.67, 4.8, .4.93, 5.07, 5.21, 5.36, 5.52, 5.68, 5.84, 6.00, 6.16, 6.33, .6.52, 6.72, 6.94, 7.16, 7.38, 7.62, 7.86, 8.10, 8.36, 8.62, .8.90, 9.20, 9.50, 9.80, 10.1,

36、10.5, 10.9, 11.36, 11.7, 12.1, .12.6, 13.1, 13.6, 14.2, 14.8, 15.5, 16.3, 17.1, 18.1, 19.1, .20.1, 21.2, 22.4, 23.7, 25.0, 26.7, 28.5, 30.4, 32.6, 35.1, .37.8, 40.7, 43.7, 46.8, 50.0, 53.4, 56.8, 60.4, 64.0, 67.8, .72.0, 76.4, 80.8, 85.4, 90.2, 95.0, 100, 105, 110, 116, .122, 128, 134, 140, 146, 152

37、, 158, 165, 172, 180; Bdata3=0.40:0.01:1.89;len3=length(Hdata3)Hmax3=Hdata3(len3);a2=polyfit(Hdata3,Bdata3,13);for n=1:151Hfit3(n)=Hmax3*(n-1)/150;Bfit3(n)=a2(1)*Hfit3(n)13+a2(2)*Hfit3(n)12+a2(3)*Hfit3(n)11+a2(4)*Hfit3(n)10+a2(5)*Hfit3(n)9+a2(6)*Hfit3(n)8+a2(7)*Hfit3(n)7+a2(8)*Hfit3(n)6+a2(9)*Hfit3(

38、n)5+a2(10)*Hfit3(n)4+a2(11)*Hfit3(n)3+a2(12)*Hfit3(n)2+a2(13)*Hfit3(n)1+a2(14);end%D24磁化曲線數(shù)據(jù)Hdata4 = 1.37, 1.38, 1.4, 1.42, 1.44, 1.46, 1.48, 1.50, 1.52, 1.54, .1.56, 1.58, 1.6, 1.62, 1.64, 1.66, 1.68, 1.70, 1.72, 1.75, .1.77, 1.79, 1.81, 1.84, 1.87, 1.89, 1.92, 1.94, 1.97, 2.00, .2.03, 2.06, 2.09,

39、2.12, 2.16, 2.20, 2.23, 2.27, 2.31, 2.35, .2.39, 2.43, 2.48, 2.52, 2.57, 2.62, 2.67, 2.73 2.79, 2.85, .2.91, 2.97, 3.03, 3.1, 3.17, 3.24, 3.31, 3.39, 3.47, 3.55, .3.63, 3.71, 3.79, 3.88, 3.97, 4.06, 4.16, 4.26, 4.37, 4.48, .4.60, 4.72, 4.86, 5.00, 5.14, 5.29, 5.44, 5.60, 5.76, 5.92, .6.10, 6.28, 6.4

40、6, 6.65, 6.85, 7.5, 7.25, 7.46, 7.68, 7.90, .5.14, 8.40, 8.38, 8.96, 9.26, 9.58, 9.86, 10.2, 10.6, 11.0, .11.4, 11.8, 12.6, 12.8, 13.3, 13.8, 14.4, 15.0, 15.7, 16.4, .17.2, 18.0, 18.9, 19.9, 20.9, 22.1, 23.5, 25.0, 26.8, 28.6, .30.7, 33.0, 35.6, 38.2, 41.1, 44.0, 47.0, 50.0, 53.5, 57.5, .61.5, 66.0,

41、 70.5, 75, 79.7, 84.5, 89.5, 94.7, 100, 105, .110, 116, 122, 128, 134, 141, 148, 155, 162, 170; Bdata4=0.40:0.01:1.89;len4=length(Hdata4)Hmax4=Hdata4(len4);a4=polyfit(Hdata4,Bdata4,13);for n=1:151Hfit4(n)=Hmax4*(n-1)/150;Bfit4(n)=a4(1)*Hfit4(n)13+a4(2)*Hfit4(n)12+a4(3)*Hfit4(n)11+a4(4)*Hfit4(n)10+a4

42、(5)*Hfit4(n)9+a4(6)*Hfit4(n)8+a4(7)*Hfit4(n)7+a4(8)*Hfit4(n)6+a4(9)*Hfit4(n)5+a4(10)*Hfit4(n)4+a4(11)*Hfit4(n)3+a4(12)*Hfit4(n)2+a4(13)*Hfit4(n)1+a4(14);（二）變壓器電壓變化率及效率曲線的繪制end%將五條磁化曲線繪制于統(tǒng)一表格中plot(Hfit,Bfit,Hfit1,Bfit1,Hfit2,Bfit2,Hfit3,Bfit3,Hfit4,Bfit4) holdxlabel('HA/cm')ylabel('BT'

43、;)holdgridclcclearsyms a1syms a2a1=solve('cos(a1)=0.85')a2=solve('cos(a2)=1')I2=0:0.1:2.0;U1=1-(I2*0.0093*cos(a1(1,1)+I2*0.048*sin(a1(1,1);U2=1-(I2*0.0093*cos(a1(2,1)+I2*0.048*sin(a1(2,1);U3=1-(I2*0.0093*cos(a2)+0.048*sin(a2);plot(I2,U1,I2,U2,I2,U3)holdxlabel('I2*')ylabel('U2*')1.變壓器的電壓輸出特性曲線的繪制程序clcclearI2=0:0.1:2.0;P1=(I2*0.85)./(I2*0.85+0.0054+I2.2*0.0093);plot(I2,P1)holdxlabel('I2*')ylabel(&#