High-dynamic single-phase Hilbert-based PLL for improved phase-jump ride-through in grid-connected inverters

The diffusion of renewable energy sources has now gained a very high importance in contributing to the electrical power needs. Grid-connected photovoltaic or wind energy conversion systems are nowadays highly integrated in the electrical grid, and they provide a consistent share of power to the nearby loads. Although this is true for high-power three-phase systems, problems related to the increasing penetration of low power, distributed generation systems into the grid structure have not been completely investigated yet. This paper proposes a control system based on a Hilbert-filter single-phase PLL with very fast response that allows the detection of fast frequency variations or phase jump in the grid voltage. The novelty resides in the use of a very short FIR transfer function to approximate the Hilbert filter in conjunction with a system that compensates the magnitude error. Simulations and experiments show that this system can be employed to increase the phase-jump ride-through capability of single phase grid-connected inverters.