www.pudn.com > HHT_power-system_power-quality_disturbances-detect > IMFeg.m, change:2010-06-18,size:1692b


 
clc 
close all 
clear all 
fs=1000; 
t=1/fs:1/fs:1; 
N=1000; 
 
y1=220*2^0.5*cos(100*pi*t); 
 
 
y2=100*2^0.5*cos(500*pi*t); 
 
q=heaviside(t-0.1)-heaviside(t-0.7); 
y3=y2.*q; 
 
 
y4=-140*2^0.5*cos(100*pi*t); 
p=heaviside(t-0.35)-heaviside(t-0.55); 
y5=y4.*p; 
 
z=y1+y3+y5; 
 
 
 
 
figure; 
subplot(4,1,1); 
plot(t,y1);ylabel('幅值(v)');xlabel('时间(s)');title('工频标准信号(MATLAB模拟给出)'); 
subplot(4,1,2); 
plot(t,y3);ylabel('幅值(v)');xlabel('时间(s)');title('加入谐波信号(MATLAB模拟给出)'); 
 
 
subplot(4,1,3); 
plot(t,y5);ylabel('幅值(v)');xlabel('时间(s)');title('加入暂降信号(MATLAB模拟给出)'); 
 
subplot(4,1,4); 
plot(t,z);ylabel('幅值(v)');xlabel('时间(s)');title('目标信号(MATLAB模拟给出)'); 
 
 
 
imf=emd(z); 
figure; 
 
 
  subplot(5,1,1) 
     plot(z); 
     ylabel('x(t)'); 
     set(gca,'box','off');title('对目标信号进行EMD分解');xlabel('时间(ms)') 
 
  subplot(5,1,2); 
     plot(imf(1,:)); 
     ylabel('IMF1'); 
     set(gca,'box','off');xlabel('时间(ms)'); 
  subplot(5,1,3); 
     plot(imf(2,:)); 
     ylabel('IMF2'); 
     set(gca,'box','off');xlabel('时间(ms)'); 
  subplot(5,1,4); 
     plot(imf(3,:)); 
     ylabel('IMF3'); 
     set(gca,'box','off');xlabel('时间(ms)'); 
  subplot(5,1,5); 
     plot(imf(4,:)); 
     ylabel('R'); 
     set(gca,'box','off');xlabel('时间(ms)'); 
 
 
  
  
  
  
 [A,fa,tt]=hhspectrum(imf(1:end-1,:));          
figure; 
plot(fa(1,:)*fs);ylabel('频率(Hz)');xlabel('时间(ms)');title('时间-频率特性曲线'); 
p1=(fa(1,:)*fs)'; 
% figure; 
% plot(fa(2,:)*fs); 
% figure; 
% plot(fa(3,:)*fs); 
 
 
 
 
 
figure; 
plot(A(1,:)');ylabel('幅值(v)');xlabel('时间(ms)');title('时间-幅值特性曲线');