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标题:
求解如下方程组，MATLAB算不出来怎么办？
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作者:
limopcb
时间:
2020-5-28 11:17
标题:
求解如下方程组，MATLAB算不出来怎么办？
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请教大神，
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求解如下方程组，九个方程九个未知数，MATLAB算不出来，很奇怪，按道理计算出来应该没问题的。感谢！
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clc;
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clear all;
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close all;
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syms v1 v2 v4 P3ref
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syms i12 i13 i14 i24 i34
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r = 0.01;
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R12 = 75*r; R13 = 125*r; R14 = 200*r; R24 = 150*r; R34 = 175*r;
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P1ref = 175e6; P2ref = 35e6; P4ref = 140e6; v3ref = 100e3;
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v3 = v3ref;
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eq1 = P1ref/v1 - (i13 + i12 + i14);
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eq2 = P2ref/v2 - (-i12 + i24);
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eq3 = P3ref/v3 - (i13 - i34);
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eq4 = P4ref/v4 - (i34 + i14 + i24);
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eq5 = (v1 - v3)/R13 - i13;
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eq6 = (v1 - v4)/R14 - i14;
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eq7 = (v1 - v2)/R12 - i12;
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eq8 = (v2 - v4)/R24 - i24;
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eq9 = (v3 - v4)/R34 - i34;
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s = solve(eq1,eq2,eq3,eq4,eq5,eq6,eq7,eq8,eq9);
作者:
House
时间:
2020-5-28 13:28
数值解试试：
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v1: 101005.230297198
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i13: 804.184237758687
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i12: 314.30767957579
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i14: 614.09162794411
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v2: 100769.499537517
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i24: 661.634997470918
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p3ref: 67678254.7078767
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i34: 127.40169067992
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v4: 99777.0470413101
作者:
artic
时间:
2020-5-28 19:45
syms v1 v2 v4 P3ref
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syms i12 i13 i14 i24 i34
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r = 0.01;
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R12 = 75*r; R13 = 125*r; R14 = 200*r; R24 = 150*r; R34 = 175*r;
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P1ref = 175e6; P2ref = 35e6; P4ref = 140e6; v3ref = 100e3;
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v3 = v3ref;
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eq1 = P1ref/v1 - (i13 + i12 + i14)==0;
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eq2 = P2ref/v2 - (-i12 + i24)==0;
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eq3 = P3ref/v3 - (i13 - i34)==0;
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eq4 = P4ref/v4 - (i34 + i14 + i24)==0;
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eq5 = (v1 - v3)/R13 - i13==0;
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eq6 = (v1 - v4)/R14 - i14==0;
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eq7 = (v1 - v2)/R12 - i12==0;
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eq8 = (v2 - v4)/R24 - i24==0;
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eq9 = (v3 - v4)/R34 - i34==0;
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eqns=[eq1,eq2,eq3,eq4,eq5,eq6,eq7,eq8,eq9]
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vars=[v1,v2,v4,P3ref,i12,i13,i14,i24,i34]
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s = vpasolve(eqns,vars)
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