A Hybrid Filtering Technique-Based PLL Targeting Fast and Robust Tracking Performance under Distorted Grid Conditions

Li, Yunlu; Yang, Junyou; Wang, Haixin; Ge, Wei; Ma, Yiming

doi:10.3390/en11040973

Cited by 15 publications

(7 citation statements)

References 26 publications

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“…Energies 2018, 11,x FOR PEER REVIEW 13 of 20 In this section, experiments are implemented on a real-time experimental platform to examine the performance of the proposed PLL. Three phase voltage signals are generated by a personal computer with a data acquisition board.…”

Section: Test Case 1: Phase Jumpmentioning

confidence: 99%

“…It is a big challenge for a grid synchronization method to extract grid frequency and phase information under such adverse conditions. Among various grid synchronization techniques, phase-locked loop (PLL) is the most widely used method in grid phase and frequency detection area for its robust performance and simple implementation [9][10][11][12]. Figure 2 shows the most common employment of PLLs in practical applications.…”

Section: Introductionmentioning

confidence: 99%

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A Modified DSC-Based Grid Synchronization Method for a High Renewable Penetrated Power System Under Distorted Voltage Conditions

Yang

et al. 2019

Energies

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With the increasing penetration of renewable energy, a weak grid with declining inertia and distorted voltage conditions becomes a significant problem for wind and solar energy integration. Grid frequency is prone to deviate from its nominal value. Grid voltages become more easily polluted by unbalanced and harmonic components. Grid synchronization technique, as a significant method used in wind and solar energy grid-connected converters, can easily become ineffective. As probably the most widespread grid synchronization technique, phase-locked loop (PLL) is required to detect the grid frequency and phase rapidly and precisely even under such undesired conditions. While the amount of filtering techniques can remove disturbances, they also deteriorate the dynamic performance of PLL, which may not meet the standard requirements of grid codes. The objective of this paper is to propose an effective PLL to tackle this challenge. The proposed PLL is based on quasi-type-1 PLL (QT1-PLL), which provides a good filtering capability by using a moving average filter (MAF). To accelerate the transient behavior when disturbance occurs, a modified delay signal cancellation (DSC) operator is proposed and incorporated into the filtering stage of QT1-PLL. By using modified DSCs and MAFs in a cascaded way, the settling time of the proposed method is reduced to around one cycle of grid fundamental frequency without degrading any disturbance rejection capability. To verify the performance, several test cases, which usually happen in high renewable penetrated power systems, are carried out to demonstrate the effectiveness of the proposed PLL. China [7,8], and caused many wind turbines to be tripped off. This highly impacted the operation of power distribution and renewable energy utilization. The grid frequency is prone to deviate from its nominal value since the inertia of the grid decreases. Grid voltages contain an amount of undesired components, such as fundamental frequency negative sequences (FFNSs) and harmonic components, which results in unbalanced and distorted grid conditions. It is an essential requirement for a renewable energy power converter to maintain stable operation with high performance under such conditions. To achieve this goal, a proper grid synchronization method is needed for all grid-connected applications. It is a big challenge for a grid synchronization method to extract grid frequency and phase information under such adverse conditions.

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Section: Test Case 1: Phase Jumpmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A Modified DSC-Based Grid Synchronization Method for a High Renewable Penetrated Power System Under Distorted Voltage Conditions

Yang

et al. 2019

Energies

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“…In order to further improve the filtering performance and dynamic response speed of SRF-PLL, many advanced three-phase PLLs based on SRF-PLL have been proposed. Most of these methods improve the performance of SRF-PLL by improving the filtering stage [10]- [13].…”

Section: Introductionmentioning

confidence: 99%

A Novel Grid Synchronization Method Based on Hybrid Filter Under Distorted Voltage Conditions

et al. 2020

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The phase-locked accuracy of conventional phase-locked method is reduced when the grid voltage contains fundamental frequency negative sequence(FFNS) component, harmonic component, and DC offset component. Aiming at this problem, a novel adaptive notch filter (NANF) is proposed, and a dual NANF (DNANF) structure is designed to eliminate the FFNS component and extract the fundamental frequency positive sequence(FFPS) component based on NANF. Furthermore, dcDNANF with DC offset rejection capability is proposed by adopting DNANF. Then a novel hybrid filter in dq-frame is designed by combining dcDNANF and the cascaded delay signal cancellation operator filter whose delay parameters are 4 and 24 in dq-frame (dqCDSC 4,24). Meanwhile, a new SRF-PLL design method is proposed based on the novel hybrid filter. This proposed method employs dqCDSC 4,24 to separate the positive and negative sequences of the voltage and eliminate the high frequency harmonics in the grid voltage, and uses dcDNANF to reject the DC offset, so as to achieve the accurate acquisition of the fundamental voltage information under distortion and unbalanced grid. Simulation and experimental results show that compared with the conventional SRF-PLL methods, the proposed method can obtain faster phase tracking speed, better phase-locked effect, faster dynamic response, and better stability. INDEX TERMS Novel adaptive notch filter (NANF), harmonic, phase-locked loop (PLL), dc offset, cascaded delay signal cancellation (CDSC).

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“…In [19], a feed forward action is used to improve the response speed. Likewise, in [20] and [21], a number of techniques are presented to remove unwanted ripples in the estimated phase, but a drift in the grid frequency is not taken into account in testing the proposed technique. In [14] an improved small signal SRF-PLL model is proposed to analyze the variations of input voltage magnitude in addition to effects of grid frequency and phase angle changes.…”

Section: Introductionmentioning

confidence: 99%

Comparison of Synchronization Techniques Under Distorted Grid Conditions

Ullah

Ashraf

2019

IEEE Access

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In grid-connected power converter applications, the phase-locked loop (PLL) is probably the most widely used grid synchronization technique, owing to its simple implementation. However, in power grids some very common problems, such as voltage distortion, voltage unbalance, and frequency instability make synchronization a challenging task. The performance of the conventional synchronous reference frame PLL (SRF-PLL) is greatly reduced in the presence of distorted grid conditions. For a polluted grid some advance PLL techniques have been proposed, such as moving average filter PLL (MAF-PLL) and cascaded delayed signal cancellation PLL (CDSC-PLL). These techniques have been mostly evaluated in the presence of odd and even harmonics but the effects of interharmonics on these synchronization techniques still needs to be investigated. In this paper, a detailed performance comparison has been made between SRF-PLL, MAF-PLL, and CDSC-PLL for grid voltages contaminated with interharmonics in the presence of different grid disturbances, such as frequency jump, phase angle jump, and dc offset. The techniques are simulated using Matlab/Simulink. The CDSC-PLL shows excellent performance as compared with other techniques in terms of dynamic response as it settles to frequency step change in a half cycle but the presence of interharmonics greatly reduces its filtering capability. On the other hand, MAF-PLL gives a ripple free behavior in frequency estimation but with a much slower dynamic response as it settles to a frequency step change in more than three cycles. SRF-PLL only performs well under harmonics free grid voltages. INDEX TERMS Grid synchronization, phase locked loop, interharmonics and power quality improvement.

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A Hybrid Filtering Technique-Based PLL Targeting Fast and Robust Tracking Performance under Distorted Grid Conditions

Cited by 15 publications

References 26 publications

A Modified DSC-Based Grid Synchronization Method for a High Renewable Penetrated Power System Under Distorted Voltage Conditions

A Modified DSC-Based Grid Synchronization Method for a High Renewable Penetrated Power System Under Distorted Voltage Conditions

A Novel Grid Synchronization Method Based on Hybrid Filter Under Distorted Voltage Conditions

Comparison of Synchronization Techniques Under Distorted Grid Conditions

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