Why I get this error ''Undefined function 'plus' for input arguments of type 'sym'.''?

Question

Traian Preda 2013-10-20

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/90866-why-i-get-this-error-undefined-function-plus-for-input-arguments-of-type-sym

评论： Walter Roberson 2013-10-20

Hi,

I triy to execute the following system of equations

syms Psiad0 Psiaq0 Rfd Lfd Ladssec R1d L1d R1q L1q Laqssec R2q L2q id0 iq0 Ll S=solve((-(1/((0.002+0.001)^2+(0.001+1*(Ladssec+Ll))*(0.001+1*(Laqssec+Ll))))*((0.002+0.001)*sin(-0.39)-(0.001+1*(Ladssec+Ll))*cos(-0.39)*(Psiad0+Laqssec*id0)-(1/((0.002+0.001)^2+(0.001+1*(Ladssec+Ll))*(0.001+1*(Laqssec+Ll))))*((0.001+1*(Laqssec+Ll))*sin(-0.39)-(0.002+0.001)*cos(-0.39))*(Psiaq0+Ladssec*iq0)))/(2*10)==-0.12,(-((0.002+0.001))*Ladssec/(((0.002+0.001)^2+(0.001+1*(Ladssec+Ll))*(0.001+1*(Laqssec+Ll)))*Lfd)*(Psiad0+Laqssec*id0)-((0.001+1*(Laqssec+Ll))*Ladssec)/(((0.002+0.001)^2+(0.001+1*(Ladssec+Ll))*(0.001+1*(Laqssec+Ll)))*Lfd)*(Psiaq0+Ladssec*iq0)+(Ladssec*iq0)/Lfd)/(2*10)==-0.069,(-((0.002+0.001))*Ladssec/(((0.002+0.001)^2+(0.001+1*(Ladssec+Ll))*(0.001+1*(Laqssec+Ll)))*L1d)*(Psiad0+Laqssec*id0)-((0.001+1*(Laqssec+Ll))*Ladssec)/(((0.002+0.001)^2+(0.001+1*(Ladssec+Ll))*(0.001+1*(Laqssec+Ll)))*L1d)*(Psiaq0+Ladssec*iq0)+(Ladssec*iq0)/L1d)/(2*10)==-0.079, (-(0.001+1*(Ladssec+Ll))*Laqssec/(((0.002+0.001)^2+(0.001+1*(Ladssec+Ll))*(0.001+1*(Laqssec+Ll)))*L1q)*(Psiad0+Laqssec*id0)-(-(0.002+0.001))*Laqssec/(((0.002+0.001)^2+(0.001+1*(Ladssec+Ll))*(0.001+1*(Laqssec+Ll)))*L1q)*(Psiaq0+Ladssec*iq0)-(Laqssec*id0)/L1q)/(2*10)==-0.003, (-(0.001+1*(Ladssec+Ll))*Laqssec/(((0.002+0.001)^2+(0.001+1*(Ladssec+Ll))*(0.001+1*(Laqssec+Ll)))*L2q)*(Psiad0+Laqssec*id0)-(-(0.002+0.001))*Laqssec/(((0.002+0.001)^2+(0.001+1*(Ladssec+Ll))*(0.001+1*(Laqssec+Ll)))*L2q)*(Psiaq0+Ladssec*iq0)-(Laqssec*id0)/L2q)/(2*10)==-0.023,-(1*Rfd*(1/((0.002+0.001)^2+(0.001+1*(Ladssec+Ll))*(0.001+1*(Laqssec+Ll))))*((0.001+1*(Laqssec+Ll))*sin(-0.39)-(0.002+0.001)*cos(-0.39))*Ladssec)/Lfd==-0.109, -(1*Rfd*(-(0.002+0.001))*Laqssec/(((0.002+0.001)^2+(0.001+1*(Ladssec+Ll))*(0.001+1*(Laqssec+Ll)))*L1q)*Ladssec)/Lfd==0.0003,-(1*R1d*(1/((0.002+0.001)^2+(0.001+1*(Ladssec+Ll))*(0.001+1*(Laqssec+Ll))))*((0.001+1*(Laqssec+Ll))*sin(-0.39)-(0.002+0.001)*cos(-0.39))*Ladssec)/L1d==-4.928,-(1*R1d*(-(0.002+0.001))*Laqssec/(((0.002+0.001)^2+(0.001+1*(Ladssec+Ll))*(0.001+1*(Laqssec+Ll)))*L2q)*Ladssec)/L1d==0.013,-(1*R1q*(1/((0.002+0.001)^2+(0.001+1*(Ladssec+Ll))*(0.001+1*(Laqssec+Ll))))*((0.002+0.001)*sin(-0.39)-(0.001+1*(Ladssec+Ll))*cos(-0.39))*Laqssec)/L1q==-0.058, -(1*R1q*((0.002+0.001))*Ladssec/(((0.002+0.001)^2+(0.001+1*(Ladssec+Ll))*(0.001+1*(Laqssec+Ll)))*Lfd)*Laqssec)/L1q==-0.0005,-(1*R2q*(1/((0.002+0.001)^2+(0.001+1*(Ladssec+Ll))*(0.001+1*(Laqssec+Ll))))*((0.002+0.001)*sin(-0.39)-(0.001+1*(Ladssec+Ll))*cos(-0.39))*Laqssec)/L2q==-1.39,-(1*R2q*((0.002+0.001))*Ladssec/(((0.002+0.001)^2+(0.001+1*(Ladssec+Ll))*(0.001+1*(Laqssec+Ll)))*Lfd)*Laqssec)/L2q==-0.011, -(1*R1q/L1q)*((0.002+0.001))*Ladssec/(((0.002+0.001)^2+(0.001+1*(Ladssec+Ll))*(0.001+1*(Laqssec+Ll)))*L1d)*Laqssec==-0.011,-(1*R2q/L2q)*((0.002+0.001))*Ladssec/(((0.002+0.001)^2+(0.001+1*(Ladssec+Ll))*(0.001+1*(Laqssec+Ll)))*L1d)*Laqssec==-0.011);

and I get this error ''Undefined function 'plus' for input arguments of type 'sym'.

Does anyone have idea what is the problem? Thanks