Design and Analysis of Enhanced Phase-Locked Loop: Methods of Lyapunov and Natural Gradient

The phase-locked loop (PLL) plays a crucial role in modern power systems, primarily for estimating line voltage parameters and tracking variations needed to synchronize and control grid-connected power converters. The enhanced phase-locked loop (EPLL) builds upon the standard PLL by tracking sinusoi...

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Main Authors: Shafayat Abrar, Muhammad Mubeen Siddiqui, Azzedine Zerguine
Format: Article
Language:English
Published: IEEE 2025-01-01
Series:IEEE Access
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Online Access:https://ieeexplore.ieee.org/document/10772435/
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author Shafayat Abrar
Muhammad Mubeen Siddiqui
Azzedine Zerguine
author_facet Shafayat Abrar
Muhammad Mubeen Siddiqui
Azzedine Zerguine
author_sort Shafayat Abrar
collection DOAJ
description The phase-locked loop (PLL) plays a crucial role in modern power systems, primarily for estimating line voltage parameters and tracking variations needed to synchronize and control grid-connected power converters. The enhanced phase-locked loop (EPLL) builds upon the standard PLL by tracking sinusoidal signal amplitude. While EPLL has been extensively explored in experimental applications, the theoretical modeling of a modified EPLL has received limited attention. Originally introduced by M. Karimi-Ghartemani et al. in IEEE Trans. Instrum. Meas., 61(4):930–940, 2012, the modified EPLL has not been fully explored in certain areas. In this work, we first address the limitations in existing gradient- and Hessian-based EPLL designs by examining stationary points in their autonomous forms. We then introduce two new derivations of the modified EPLL for single-phase power systems, which incorporate synthesized quadrature components of the input signal. These derivations are based on Lyapunov stability theory and natural gradient optimization. We comprehensively analyze convergence and stability by employing averaging theory and Poincaré maps to establish stability limits for the filter’s proportional and integral gains. Additionally, we show that the design and tuning of the EPLL can be simplified by managing all three core equations with a single control parameter. Simulation results confirm that, within the derived gain limits, the EPLL effectively tracks sudden changes in amplitude, phase, and frequency without inducing double-frequency effects.
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spelling doaj-art-92674395cf5f45658b88fbec7687d6a72025-01-09T00:01:26ZengIEEEIEEE Access2169-35362025-01-01132409242310.1109/ACCESS.2024.351061410772435Design and Analysis of Enhanced Phase-Locked Loop: Methods of Lyapunov and Natural GradientShafayat Abrar0https://orcid.org/0000-0002-6857-1446Muhammad Mubeen Siddiqui1Azzedine Zerguine2https://orcid.org/0000-0002-2621-4969DSSE, Habib University, Karachi, PakistanDSSE, Habib University, Karachi, PakistanElectrical Engineering Department, the Center for Communication Systems and Sensing, and the Center for Smart Mobility & Logistics, King Fahd University of Petroleum and Minerals (KFUPM), Dhahran, Saudi ArabiaThe phase-locked loop (PLL) plays a crucial role in modern power systems, primarily for estimating line voltage parameters and tracking variations needed to synchronize and control grid-connected power converters. The enhanced phase-locked loop (EPLL) builds upon the standard PLL by tracking sinusoidal signal amplitude. While EPLL has been extensively explored in experimental applications, the theoretical modeling of a modified EPLL has received limited attention. Originally introduced by M. Karimi-Ghartemani et al. in IEEE Trans. Instrum. Meas., 61(4):930–940, 2012, the modified EPLL has not been fully explored in certain areas. In this work, we first address the limitations in existing gradient- and Hessian-based EPLL designs by examining stationary points in their autonomous forms. We then introduce two new derivations of the modified EPLL for single-phase power systems, which incorporate synthesized quadrature components of the input signal. These derivations are based on Lyapunov stability theory and natural gradient optimization. We comprehensively analyze convergence and stability by employing averaging theory and Poincaré maps to establish stability limits for the filter’s proportional and integral gains. Additionally, we show that the design and tuning of the EPLL can be simplified by managing all three core equations with a single control parameter. Simulation results confirm that, within the derived gain limits, the EPLL effectively tracks sudden changes in amplitude, phase, and frequency without inducing double-frequency effects.https://ieeexplore.ieee.org/document/10772435/Enhanced phase-locked loopgradient flownatural gradientLyapunov stabilityPoincaré map
spellingShingle Shafayat Abrar
Muhammad Mubeen Siddiqui
Azzedine Zerguine
Design and Analysis of Enhanced Phase-Locked Loop: Methods of Lyapunov and Natural Gradient
IEEE Access
Enhanced phase-locked loop
gradient flow
natural gradient
Lyapunov stability
Poincaré map
title Design and Analysis of Enhanced Phase-Locked Loop: Methods of Lyapunov and Natural Gradient
title_full Design and Analysis of Enhanced Phase-Locked Loop: Methods of Lyapunov and Natural Gradient
title_fullStr Design and Analysis of Enhanced Phase-Locked Loop: Methods of Lyapunov and Natural Gradient
title_full_unstemmed Design and Analysis of Enhanced Phase-Locked Loop: Methods of Lyapunov and Natural Gradient
title_short Design and Analysis of Enhanced Phase-Locked Loop: Methods of Lyapunov and Natural Gradient
title_sort design and analysis of enhanced phase locked loop methods of lyapunov and natural gradient
topic Enhanced phase-locked loop
gradient flow
natural gradient
Lyapunov stability
Poincaré map
url https://ieeexplore.ieee.org/document/10772435/
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AT muhammadmubeensiddiqui designandanalysisofenhancedphaselockedloopmethodsoflyapunovandnaturalgradient
AT azzedinezerguine designandanalysisofenhancedphaselockedloopmethodsoflyapunovandnaturalgradient