main.cpp

采用软件模拟的FFT方式谐波计算方法

//---------------------------------------------------------------------------

#include <vcl.h>
#pragma hdrstop

#include "main.h"
#include <math.h>
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
double dd = 0;
double dataR[128];
TForm1 *Form1;
//---------------------------------------------------------------------------
__fastcall TForm1::TForm1(TComponent* Owner)
    : TForm(Owner)
{

}

//---------------------------------------------------------------------------
void __fastcall TForm1::Button1Click(TObject *Sender)
{
double kk[3], ll;
double vref[3];
double ph[3];
    ph[0] = 1;
    ph[1] = this->phb->Text.ToDouble();
    ph[2] = this->phc->Text.ToDouble();

    vref[0] = this->voltagea->Text.ToDouble()*sqrt(2);
    vref[1] = this->voltageb->Text.ToDouble()*sqrt(2);
    vref[2] = this->voltagec->Text.ToDouble()*sqrt(2);

    this->Chart1->Series[0]->Clear();
    for( Byte xx = 0; xx < 128; xx++ )
    {
        ll = sin( 314.15926 * xx / 6400 );
        ll = vref[0] * ll + vref[1] * sin( 314.15926 * ph[1]*xx / 6400) + vref[2] * sin( 314.15926 * ph[2]*xx / 6400 );
        dataR[xx] = ll;
    }

    for( Byte xx = 0; xx < 128; xx++ )
    {
        this->Chart1->Series[0]->Add( dataR[xx] ,AnsiString(xx+1),this->Chart1->Series[0]->SeriesColor);
    }
}
//---------------------------------------------------------------------------
void __fastcall TForm1::Button2Click(TObject *Sender)
{
double TR,TI,dataI[128],temp,w[32];
Byte x0,x1,x2,x3,x4,x5,x6,i,xx;
int L,j,k,b,p;
double sin_tab[64],cos_tab[64];

    for(k = 0; k < 64; k++)
    {
        cos_tab[k] = cos(2*3.1415926/128*k);
        sin_tab[k] = sin(-(2*3.1415926/128*k));
    }
	for(i=0;i<128;i++)
	{
		x0=x1=x2=x3=x4=x5=0;
		x0=i&0x01; x1=(i/2)&0x01; x2=(i/4)&0x01; x3=(i/8)&0x01;
		x4=(i/16)&0x01; x5=(i/32)&0x01, x6 = (i/64)&0x01;
		xx=x0*64+x1*32+x2*16+x3*8+x4*4+x5*2+x6;
		dataI[xx]=dataR[i];
	}
	for(i=0;i<128;i++)
	{ 
		dataR[i]=dataI[i];
		dataI[i]=0; 
	}
	//************** following code FFT *******************
	for(L=1;L<=7;L++)	//for(1)
	{
		b=1; 
		i=L-1;
		while(i>0)
		{
			b=b*2; 
			i--;
		} // b= 2^(L-1) 
		for(j=0;j<=b-1;j++) // for (2) 
		{ 
			p=1; 
			i=7-L;
			while(i>0) // p=pow(2,7-L)*j; 
			{
				p=p*2; 
				i--;
			}
			p=p*j;
			for(k=j;k<128;k=k+2*b) // for (3)
			{ 
				TR=dataR[k]; TI=dataI[k]; temp=dataR[k+b];
				dataR[k]=dataR[k]+dataR[k+b]*cos_tab[p]+dataI[k+b]*sin_tab[p];
				dataI[k]=dataI[k]-dataR[k+b]*sin_tab[p]+dataI[k+b]*cos_tab[p];
				dataR[k+b]=TR-dataR[k+b]*cos_tab[p]-dataI[k+b]*sin_tab[p];
				dataI[k+b]=TI+temp*sin_tab[p]-dataI[k+b]*cos_tab[p];
			} // END for (3)
		} // END for (2)
	} // END for (1)
    this->ListBox1->Clear();

	for(i=0;i<32;i++)
	{ // 只需要32次以下的谐波进行分析
		w[i]=sqrt((dataR[i]*dataR[i]+dataI[i]*dataI[i])*2);
		w[i]=w[i]/128;

	}
	w[0]=w[0]/2;
    for(i= 1; i<32; i++)
    {
        String tt = "第"+AnsiString(i)+"次谐波= ";
        tt = tt + tt.FormatFloat("0.0000",w[i]) +"V";
        this->ListBox1->Items->Add(tt);
    }
    this->ListBox1->ItemIndex = 0;

}
//---------------------------------------------------------------------------