1、微機繼電保護算法仿電控學(xué)院一.兩點乘積算法仿真(1)matlab中編寫的程序N=12;t=(0:0.02/N:0.02)'m=size(t);y=sin(2*pi*50*t);y1=zeros(N4,1);y(1:m-N/4);ym=sqrt(y.A2+y1.A2);subplot(3,2,1)plot(t,y,'r.',t,y1,'xb');legend('y(k)','y(k-T/4)');title('兩點乘積算法N=12');subplot(3,2,2)holdon;plot(t,ym,'-

2、r');axis(0,0.02,0,1.2);xlabel('t/s');ylabel('ym');title('兩點乘積算法算的有效值N=12');text(0.01,0.6,'N=12');N=16;t=(0:0.02/N:0.02)'m=size(t);y=sin(2*pi*50*t);y1=zeros(N4,1);y(1:m-N/4);ym=sqrt(y.A2+y1.A2);subplot(3,2,3)plot(t,y,'r.',t,y1,'xb');legend('

3、y(k)','y(k-T/4)');title('兩點乘積算法N=16');subplot(3,2,4)holdon;plot(t,ym,'-r');axis(0,0.02,0,1.2);xlabel('t/s');ylabel('ym');title('兩點乘積算法算的有效值N=16');text(0.01,0.6,'N=16');N=24;t=(0:0.02/N:0.02)'m=size(t);y=sin(2*pi*50*t);y1=zeros(N/4,1);y(

4、1:m-N/4);ym=sqrt(y.A2+y1.A2);subplot(3,2,5)plot(t,y,'r.',t,y1,'xb');legend('y(k)','y(k-T/4)');title('兩點乘積算法N=24');subplot(3,2,6)holdon;plot(t,ym,'-r');title('兩點乘積算法算的有效值N=24');axis(0,0.02,0,1.2);xlabel('t/s');ylabel('ym');text(0

5、.01,0.6,'N=24');(2)仿真出的波形(3)流程圖二.傅里葉算法仿真(1)matlab中編寫的程序T=0.02;t1=0.02;N=12;Ts=T/N;t=0:Ts:4*T;y=(exp(-t/t1)-cos(2*pi*50*t);subplot(3,2,1);plot(t,y,'.r');xlabel('t/ms');ylabel('y(t)');title('輸入信號N=12');a=1;i=1:N;bs=sin(2*pi*i/N);bc=cos(2*pi*i/N);ys=filter(bs,a,y

6、);yc=filter(bc,a,y);ym=2*abs(complex(ys,yc)/N;subplot(3,2,2);holdonplot(t,ym)xlabel('t/ms');ylabel('ym');title('傅里葉算法計算的有效值N=12');holdonT=0.02;t1=0.02;N=16;Ts=T/N;t=0:Ts:4*T;y=(exp(-t/t1)-cos(2*pi*50*t);subplot(3,2,3);plot(t,y,'.r');xlabel('t/ms');ylabel('

7、y(t)');title('輸入信號N=16');a=1;i=1:N;bs=sin(2*pi*i/N);bc=cos(2*pi*i/N);ys=filter(bs,a,y);yc=filter(bc,a,y);ym=2*abs(complex(ys,yc)/N;subplot(3,2,4);plot(t,ym)xlabel('t/ms');ylabel('ym');title('傅里葉算法計算的有效值N=16');T=0.02;t1=0.02;holdonN=24;Ts=T/N;t=0:Ts:4*T;y=(exp(-t/t1)-cos(2*pi*50*t);subplot(3,2,5);plot(t,y,'.r');xlabel('t/ms');ylabel('y(t)');title('輸入信號N=24');a=1;i=1:N;bs=sin(2*pi*i/N);bc=cos(2*pi*i/N);ys=filter(bs,a,y);yc=filter(bc,a,y);ym=2*abs(complex(ys,yc)/N;subplot(3,2,6);plot(t,y