Inertial PLL of Grid-connected Converter for Fast Frequency Support

Frequency support capability for the grid-connected converter (GCC) is one of the basic safeguards for the stability of renewables-dominated power systems. In this paper, analogous to the motion equation of a synchronous generator (SG), an inertial phase-locked loop (iPLL) is proposed for GCC to achieve fast frequency support. The iPLL introduces the inertial and damping loops into the classic PLL structure to emulate the natural frequency regulation characteristics of a SG. Compared with the existing methods, the iPLL has a faster frequency response and is simpler in design and implementation. Finally, the proposed iPLL method is validated by experiments.