t=0:(0.02/128):(0.02-0.02/128);
x=10+10*cos(100*pi*t)+2*cos(500*pi*t+pi/6)+1*cos(1300*pi*t+pi/3);
Isum=0;
for i=1:128
    Isum=x(i)+Isum;
end;
    Idir=Isum/128;     %直流分量有效值
    
y=fft(x,128)/64;
sum=0;
for i=1:128
re=real(y);
im=imag(y);
end;
sum=0;
for i=2:32
ia2(i)=(re(i)^2+im(i)^2)/2; 
ia(i)=sqrt(ia2(i));%ia各次諧波有效值
sum=sum+ia2(i);
end
iaa=sqrt(sum); %iaa為a相總注入諧波電流有效值
iab=ia; %iab為a相K次諧波電流有效值
sum=0;
iahmax1=ia(1);%iahmax1為幅值最大的
iahmax2= ia(1);% iahmax2為幅值次大的
iahmax3= ia(1);% iahmax3為幅值第三大的
for i=3:32
iac(i)=ia(i)/ia(2);%iac 為a相k次電流畸變率
end;
for i=2:32
sum=sum+ia2(i);
if  (ia(i)> iahmax1)
iahmax3=iahmax2;
iahmax2=iahmax1;
iahmax1=ia(i);
elseif (ia(i)> iahmax2)
iahmax3=iahmax2;
iahmax2=ia(i);
elseif (ia(i)> iahmax3)
	iahmax3=ia(i);
end;
end;
iad=sqrt(sum-ia2(2))/ia(2);%iad為a相總注入電流諧波電流畸變率

sum1=0;
for i=1:128
    sum1=sum1+x(i)^2;
end;
iae=sqrt(sum1/128-sum);%iae為間諧波注入電流最大估計值
sum=0;
sum1=0;
for i=1:15
 sum=sum+ia2(2*i+1);
 sum1=sum1+ia2(2*i);
end;
sum1=sum1+ia2(32);
iaf=sqrt(sum);%iaf為偶次諧波電流有效值
iag=sqrt(sum1);%iag為奇次諧波電流有效值

iak=max(iac);%iak為各次諧波電流畸變率最大的