微机继电保护matlab算法仿真(有源程序)

微

机

继

电

保

护

算

法

仿

真

电控学院

一．两点乘积算法仿真（1）m atlab中编写的程序

N=12;

t=(0:0.02/N:0.02)';

m=size(t);

y=sin(2*pi*50*t);

y1=[zeros(N/4,1);y(1:m-N/4)];

ym=sqrt(y.^2+y1.^2);

subplot(3,2,1)

plot(t,y,'r.',t,y1,'xb');

legend('y(k)','y(k-T/4)');

title('两点乘积算法N=12');

subplot(3,2,2)

hold on;

plot(t,ym,'-r');

axis([0,0.02,0,1.2]);

xlabel('t/s');

ylabel('ym');

title('两点乘积算法算的有效值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(N/4,1);y(1:m-N/4)];

ym=sqrt(y.^2+y1.^2);

subplot(3,2,3)

plot(t,y,'r.',t,y1,'xb');

legend('y(k)','y(k-T/4)'); title('两点乘积算法N=16');

subplot(3,2,4)

hold on;

plot(t,ym,'-r');

axis([0,0.02,0,1.2]);

xlabel('t/s');

ylabel('ym');

title('两点乘积算法算的有效值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(1:m-N/4)];

ym=sqrt(y.^2+y1.^2);

subplot(3,2,5)

plot(t,y,'r.',t,y1,'xb');

legend('y(k)','y(k-T/4)');

title('两点乘积算法N=24');

subplot(3,2,6)

hold on;

plot(t,ym,'-r');

title('两点乘积算法算的有效值N=24'); axis([0,0.02,0,1.2]);

xlabel('t/s');

ylabel('ym');

text(0.01,0.6,'N=24');

（2）仿真出的波形

（3）流程图

输入信号

y=sin(2*pi*50*t)

m=size(t)；得到离散的两点y1=[zeros(N/4,1);y(1:m-N/4)]

输出ym=sqrt(y.^2+y1.^2) N=12，即采样频率

f=600HZ，原始信号离

散化

二．傅里叶算法仿真（1）matlab中编写的程序

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('输入信号N=12');

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(3,2,2);

hold on

plot(t,ym)

xlabel('t/ms');

ylabel('ym');

title('傅里叶算法计算的有效值N=12'); hold on

T=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('y(t)');

title('输入信号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('傅里叶算法计算的有效值N=16'); T=0.02;

t1=0.02;

hold on

N=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('输入信号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,ym)

xlabel('t/ms');

ylabel('ym');

title('傅里叶算法计算的有效值N=24');