In a perfect world, VFDs do not create third harmonics, as third and other triplen harmonics cancel because of the three-phase nature of VFDs. If, however, the voltage relationship between phases A, B, and C is unbalanced, cancelation cannot occur completely, and VFDs can create triplen harmonics.
Click How Drive Changes Motor Speed at the bottom of page for more detail.i have already gone through this, bt it doesnt say about the operation of a three phase inverter=/
by Jake Hertz
by Jake Hertz
by Duane Benson