Electrotechnical Systems

187Electric Machine and Electric Drive Simulation

Nsat=9;%The number points of magnetization curve

Y=zeros(2,Nsat);

Y(1,1)=0;Y(1,2)=60.5;Y(1,3)=121;Y(1,4)=181.5;Y(1,5)=242;

Y(1,6)=302.5;

Y(1,7)=363.5;Y(1,8)=423.5;Y(1,9)=488;% Excitation current

Y(2,1)=0;Y(2,2)=0.05;Y(2,3)=0.09;Y(2,4)=0.12;Y(2,5)=0.142;

Y(2,6)=0.15;

Y(2,7)=0.156;Y(2,8)=0.16;Y(2,9)=0.162;%Flux

If=zeros(1,Nsat);F=zeros(1,Nsat);

If=Y(1,:);

F=Y(2,:);

p=polyfit(If,F,5);%approximation

for j=1:Nsat;

s(j)=(j−1)*60.5;

z(j)=polyval(p,s(j) );%calculation

end;

plot(If,F,‘k’,If,z,‘.k’)%comparison

grid

dp=polyder(p);%output of the polynomial

for j=1:Nsat;

s(j)=(j−1)*60.5;

Ld(j)=polyval(dp,s(j) );%inductance calculation

end;

figure(2)

plot(If,Ld,‘k’)

grid

Fres=0.003;

save dc_ser

DCM has the same data as in Figure ...