Prefiltered Synchronization Structure for Grid-Connected Power Converters to Reduce the Stability Impact of PLL Dynamics

Garcia, J. Ignacio; Candela, José Ignacio; Catalán, Pedro

doi:10.1109/jestpe.2020.3026916

Cited by 19 publications

(6 citation statements)

References 28 publications

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“…where ω = ω 0 +∆ω, sin(∆ωT s )≅∆ωT s , cos(∆ωT s )≅1, ω 0 (=2πf 0 ) is the nominal fundamental angular frequency, f 0 is the nominal fundamental frequency, ∆ω (=2π∆f) is the deviation of the fundamental angular frequency and ∆f is the deviation of the fundamental frequency. Expression (12) can be rearranged to calculate the fundamental frequency deviation, as given by…”

Section: Fundamental Frequency Estimationmentioning

confidence: 99%

“…A filtering algorithm is also demanded by a phase-locked loop (PLL)-based method for tracking the grid frequency under grid disturbances [9]. In this case, either a pre-filter or an in-loop filter can be integrated with the PLL [10][11][12]. However, the use of the auxiliary filter may create slower response of the PLL for generating the grid frequency.…”

Section: Introductionmentioning

confidence: 99%

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Three‐phase algorithm for independent single‐phase grid frequency estimation under grid disturbances

Reza

Hossain

2022

IET Generation Trans & Dist

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This paper reports an algorithm for quick and precise estimation of the single‐phase grid frequency under DC offset and both odd and even harmonics. The proposed single‐phase grid frequency estimation method is derived from a three‐phase relation. It relies on a recursive discrete Fourier transform‐based orthogonal signal generator and a two samples‐based algorithm. The proposed approach is simple, demands low computational effort and generates the single‐phase grid frequency at a cost of only one fundamental period as the transient response time under the DC offset and both odd and even harmonics condition. It also produces enhanced performance when compared to several single‐phase grid frequency estimation methods documented in the technical literature. Computer simulations and laboratory experiments are conducted to demonstrate the usefulness of the proposed single‐phase grid frequency estimation method.

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Section: Fundamental Frequency Estimationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Three‐phase algorithm for independent single‐phase grid frequency estimation under grid disturbances

Reza

Hossain

2022

IET Generation Trans & Dist

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“…To address this problem in the relevant literature, sequence extraction and prefiltering loop are adopted before the synchronization unit to account for asymmetries and harmonics. Recently, prefiltered synchronization has been studied in the context of weak grid connection [42]- [44], where prefiltering loops are adopted to modify the bandwidth of the PLL. Prefiltering results in more complex PLL synchronization units, see [45] and references therein, where the common feature among them is adding a low-pass filtering effect to the normal PLL dynamics.…”

Section: Introductionmentioning

confidence: 99%

“…Prefiltering results in more complex PLL synchronization units, see [45] and references therein, where the common feature among them is adding a low-pass filtering effect to the normal PLL dynamics. But this makes the stability analysis complicated, particularly using MIMO impedance models [44], where the low-pass filtering effect is against the stability margin of the system, which is analyzed in this work.…”

Section: Introductionmentioning

confidence: 99%

Explicit Impedance Modeling and Shaping of Grid-Connected Converters via an Enhanced PLL for Stabilizing the Weak Grid Connection

et al. 2022

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The voltage source converters (VSCs) are used to interface and control the renewable energy resources that are integrated into the power grids. However, a weak grid connection raises a stability problem for grid synchronization of the grid-feeding current-controlled VSCs (CCVSCs). This paper handles modeling and controller design for stabilizing the weak grid connection of CCVSCs. The impedance modeling/shaping of the VSC has been recognized as an effective tool to analyze and design the dynamics of the VSC. But an explicit and accurate impedance model of the CCVSC is required. Particularly, modeling the impact of the phase-locked loop (PLL) synchronization unit on the impedance model of the CCVSC is complex. Therefore, at first, an efficient impedance model of the CCVSC is developed while the impact of the PLL is rigorously considered through a complex procedure that results in an explicit/accurate impedance model. The developed impedance model is used to conduct passivity/weak grid connection stability analysis to clarify the underlying causes of instability problems. Then, a novel PLL, with an in-loop low-pass filter (LPF) to account for harmonics/asymmetries, is proposed with enhanced characteristics using the state feedback control. The impedance shaping method (with the aid of the impedance model) is utilized to design the state feedback gains. The state feedback loops provide degrees of freedom for bandwidth design of the PLL considering the current/power control loops and stabilize the system under weak grid connection/distorted conditions. Simulation results prove the accuracy and effectiveness of the models.

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“…Additionally, [11] proposes a bandpass filter method to weaken the impact of the negative resistance. Reference [12] proposes a pre-filter method in the PLL to reduce this negative resistance impact. However, the specific enlarged quantity of the stability range is not revealed in these existing research.…”

Section: Introductionmentioning

confidence: 99%

A Simple Impedance Reshaping Method for Stability Enhancement of Grid-Following Inverter Under Weak Grid

Huang

Zhou

et al. 2021

2021 IEEE 12th International Symposium on Power Electronics for Distributed Generation Systems (PEDG)

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The conventional vector current control (VCC) scheme has been widely used in the grid-connected inverter systems. However, it suffers from power limitation problems under weak grid conditions. This paper reveals that the dynamic effect of the phase-locked loop (PLL) is the main reason for destabilizing the small-signal stability of the grid-following inverter. The positive feedback introduced by the PLL can be observed from the small-signal control structure. Reshaping the converter output impedance can counteract the positive feedback and reduce the negative resistance in the impedance model. A novel impedance reshaping method is proposed in this paper, which can enhance the small-signal stability and extend the stability range of the system. Simulation results verify the effectiveness of the proposed method.

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Prefiltered Synchronization Structure for Grid-Connected Power Converters to Reduce the Stability Impact of PLL Dynamics

Cited by 19 publications

References 28 publications

Three‐phase algorithm for independent single‐phase grid frequency estimation under grid disturbances

Three‐phase algorithm for independent single‐phase grid frequency estimation under grid disturbances

Explicit Impedance Modeling and Shaping of Grid-Connected Converters via an Enhanced PLL for Stabilizing the Weak Grid Connection

A Simple Impedance Reshaping Method for Stability Enhancement of Grid-Following Inverter Under Weak Grid

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