Inverse clarke transformation in generating SVPWM using 28335

Hi,guys!

In "svgen.c "  which I downloaded from www.ti.com.

The inverse clarke transformation is :

// Inverse clarke transformation

    Va = v->Ubeta;

    Vb = _IQmpy(_IQ(-0.5),v->Ubeta) + _IQmpy(_IQ(0.8660254),v->Ualpha);  // 0.8660254 = sqrt(3)/2 

    Vc = _IQmpy(_IQ(-0.5),v->Ubeta) - _IQmpy(_IQ(0.8660254),v->Ualpha);  // 0.8660254 = sqrt(3)/2

but,the clarke transformation is:

Ualpha=Va;

Ubeta=(2*Vb+Va)/sqrt(3);

so the inverse clarke transformation should be

Va= Ualpha;                    / / not Ubeta

Vb= Ubeta*sqrt(3)*0.5-Ualpha*0.5;

So,I'm confused,is the program    "svgen.c"  from  www.ti.com  wrong?

Thanks very much!