On the behavior of three-phase inverters in the new smart grid context

The effects of interharmonic distortion on three-phase inverters whose control is based on the use of PLL systems are analyzed. After some brief recalls on the general scheme of a three-phase PLL, a linear analysis in the presence of interharmonics is developed in terms of amplitude and phase modulation effects on the PLL errors. Finally, a sensitivity analysis aimed to show the effects of different design choices of the PLL on the frequency and phase angle estimation errors and on the dynamic response is reported.