SVPWM程序 CMPA输出为0有可能是什么原因

float temp;

 float X,Y,Z, t1,t2;

 Uint16 A,B,C,N,Sector;

 float Ta, Tb, Tc;

 float K=1.73205081;//sqrt(3)





 X= K*p->Ubeta/p->Vdc*p->T;

 Y=(K*p->Ubeta+3*p->Ualpha)/(2*p->Vdc)*p->T;

 Z=(K*p->Ubeta-3*p->Ualpha)/(2*p->Vdc)*p->T;

//

 if(p->Ubeta>0)

   {A=1;}

 else

   {A=0;}



 if( (K*p->Ualpha-p->Ubeta)>0 )

   {B=1;}

 else

   {B=0;}

 

 if((-K*p->Ualpha-p->Ubeta)>0)

   {C=1;}

 else

   {C=0;}



 N=A+2*B+4*C;

//

 switch(N)

 {

case 1:{Sector=2;break;}

case 2:{Sector=6;break;}

case 3:{Sector=1;break;}

case 4:{Sector=4;break;}

case 5:{Sector=3;break;}

case 6:{Sector=5;break;}

 default:{;}

 }

 //

switch(Sector)

{

case 1: {t1=-Z; t2= X;break;}

case 2: {t1= Z; t2= Y;break;}

case 3: {t1= X; t2=-Y;break;}

case 4: {t1=-X; t2= Z;break;}

case 5: {t1=-Y; t2=-Z;break;}

case 6: {t1= Y; t2=-X;break;}

  default:{;}

}



if((t1+t2)>p->T)//对过调制情况进行调整

 {

  temp=t1+t2;

  t1=t1*p->T/temp;

  t2=t2*p->T/temp;

 }



//

 Ta=(p->T-t1-t2)/4;//作用时间分配

 Tb=Ta+(t1/2);

 Tc=Tb+(t2/2); 



 switch(Sector)

  {

        case 1: {p->Tcmpa=Ta; p->Tcmpb=Tb; p->Tcmpc=Tc; break;}

        case 2: {p->Tcmpa=Tb; p->Tcmpb=Ta; p->Tcmpc=Tc; break;}

        case 3: {p->Tcmpa=Tc; p->Tcmpb=Ta; p->Tcmpc=Tb; break;}

        case 4: {p->Tcmpa=Tc; p->Tcmpb=Tb; p->Tcmpc=Ta; break;}

        case 5: {p->Tcmpa=Tb; p->Tcmpb=Tc; p->Tcmpc=Ta; break;}

        case 6: {p->Tcmpa=Ta; p->Tcmpb=Tc; p->Tcmpc=Tb; break;} 

    default:{;}



  }