Modeling and Tuning of Circular Limit Cycle Oscillator FLL With Pre-Loop Filter

Miao Lin Pay, Hafiz Ahmed

    Research output: Contribution to journalArticlepeer-review

    40 Citations (Scopus)
    157 Downloads (Pure)


    Circular limit cycle oscillator-frequency-locked loop (CLO-FLL) is a recently proposed advanced nonlinear technique for the parameter estimation of grid voltage signal. It has fast convergence and can handle dc bias/offset. Nevertheless, the performance degrades in the presence of harmonics. In this letter, we propose the application of preloop filtering to enhance the robustness of the CLO-FLL in the presence of harmonics. Preloop filtering slightly increases the computational complexity. However, number of parameters to tune remain the same. The small-signal modeling, tuning, and performance comparisons of both techniques are performed in this letter.

    Original languageEnglish
    Article number8617680
    Pages (from-to)9632-9635
    Number of pages4
    JournalIEEE Transactions on Industrial Electronics
    Issue number12
    Early online date17 Jan 2019
    Publication statusPublished - 1 Dec 2019

    Bibliographical note

    © 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.

    Copyright © and Moral Rights are retained by the author(s) and/ or other copyright owners. A copy can be downloaded for personal non-commercial research or study, without prior permission or charge. This item cannot be reproduced or quoted extensively from without first obtaining permission in writing from the copyright holder(s). The content must not be changed in any way or sold commercially in any format or medium without the formal permission of the copyright holders.


    • Frequency estimation
    • frequency-locked loop (FLL)
    • phase-locked loop (PLL)
    • preloop filter

    ASJC Scopus subject areas

    • Control and Systems Engineering
    • Electrical and Electronic Engineering


    Dive into the research topics of 'Modeling and Tuning of Circular Limit Cycle Oscillator FLL With Pre-Loop Filter'. Together they form a unique fingerprint.

    Cite this