A high performance PLL for polluted utility grid based on cascade adaptive notch filters

A high performance Phase-Locked Loop (PLL) based on cascade adaptive notch filters (ANF) is proposed for polluted utility grid in this paper. The proposed cascade structure can regenerate a new signal similar to the fundamental component of the original grid voltage sample signal with the same amplitude and no phase shift. Compared to traditional PLL, The proposed PLL is more accurate especially when the grid voltage contains harmonics. The static behavior of noise rejection and harmonics rejection is verified by simulations and experiments. The dynamic performance of step frequency tracking is also evaluated. Simulations and experiments show that the proposed PLL not only has small static errors but also has a quick dynamic response.