Frequency Adaptive Proportional Feedforward Repetitive Control Based on Farrow Structure Filter for LCL Grid-Tied Inverters

Traditional repetitive control (TRC) can track current reference signal and suppress harmonic signals simultaneously in grid-tied inverter systems. However, the grid frequency generally varies in microgrid when there is a discrepancy between generated power and load demand, leading to a deterioratio...

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Bibliographic Details
Main Authors: Junfeng Zhang, Zhaowei Sun, Qiangsong Zhao, Hengyi Li
Format: Article
Language:English
Published: IEEE 2024-01-01
Series:IEEE Access
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Online Access:https://ieeexplore.ieee.org/document/10776994/
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Summary:Traditional repetitive control (TRC) can track current reference signal and suppress harmonic signals simultaneously in grid-tied inverter systems. However, the grid frequency generally varies in microgrid when there is a discrepancy between generated power and load demand, leading to a deterioration in accurate tracking and suppression performance of the TRC. To this end, a frequency adaptive proportional feedforward repetitive control (FA-PFRC) is proposed in this paper. A feedforward channel is added to the inner model of the TRC to improve the dynamic performance of the system, and a finite impulse response (FIR) filter based on Farrow structure is used to achieve an accurate approximation of the fractional delay due to grid frequency fluctuations. The structure of the FA-PFRC is analyzed, and then the stability and harmonic reduction properties offered by the FA-PFRC are examined. Moreover, the realization method of the FA-PFRC is analyzed, and the parameter design process is given with the LCL grid-tied inverter as an example. Finally, experimental results demonstrate that the FA-PFRC maintains effective harmonic suppression and exhibit rapid dynamic response under grid frequency variation and weak grid conditions.
ISSN:2169-3536