A Study on Three-Phase FLLs

Golestan, Saeed; Guerrero, Josep M.; Vasquez, Juan C.; Abusorrah, Abdullah; Al‐Turki, Yusuf

doi:10.1109/tpel.2018.2826068

Cited by 95 publications

(43 citation statements)

References 22 publications

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“…As it is clear, the presence of harmonics in the voltage and, therefore, in the PLL input is mainly because of the proliferation of non-linear loads. According to the standard SRF-PLL and based on (22)- (27), the presence of a harmonic of order h in the SRF-PLL input results in a disturbance component of order h − 1 in the control loop of PLL.…”

Section: Case Studymentioning

confidence: 99%

“…However, in a grid with harmonically distortion and unbalanced voltage, its performance and ability in filtering the grid voltage disturbances reduces [24]. Therefore, many enhanced SRF-PLLs with a high capability to reject the disturbance which consist of different inloop filter and prefiltering have been designed in recent years [24][25][26][27][28][29]. In this paper, the SRF-PLL with in-loop MAF is implemented which has high performance in harmonic distortion.…”

Section: Introductionmentioning

confidence: 99%

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To study unplanned islanding transient response of microgrid by implementing MSOG and SRF‐PLL based hierarchical control in the presence of non‐linear loads

Niazi

Vasegh

Birjandi

2020

IET Renewable Power Generation

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This study considers the hierarchical control of microgrid and harmonic compensation of non-linear load specially in transition from grid-connected to unplanned islanding. The proposed controllers are based on the stationary reference frame with hierarchical control levels (inner, primary, and secondary). In the inner control loop, proportional and multi-resonant voltage and current controllers for three-phase voltage source inverters are proposed. Moreover, a droop control is used to share active and reactive power in the primary control loop. To achieve decoupled active and reactive power sharing, virtual impedance loop is implemented, too. The mentioned procedure increases the total impedance and consequently reduces the initial current and subsequently facilitates the continuous connection of DGs to the MG. To attain smoother transition, selective harmonic virtual impedance is applied by multiple second-order generalised integrator module to extract the fundamental positive sequence and harmonic components of the output current of the DGs. In secondary control level, synchronisation procedure is considered to make connection and restoration by the advanced three-phase synchronous reference frame PLL with in-loop moving average filter which significantly enhances its disturbance rejection capability. The results are shown smoother transition, robustness, and high performance of the proposed hierarchical control VSIs during variation of system configuration.

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Section: Case Studymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

To study unplanned islanding transient response of microgrid by implementing MSOG and SRF‐PLL based hierarchical control in the presence of non‐linear loads

Niazi

Vasegh

Birjandi

2020

IET Renewable Power Generation

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“…There are various techniques to estimate the frequency or phase, such as discrete Fourier transformation, Kalman filter, phase locked loop (PLL), Wavelet transformation, etc. Among these techniques, PLL receives wide attention because of its excellent performance and simple structure [14,15]. It behaves well in normal cases, but the excellent dynamical performance is at the expense of disturbance resistance ability.…”

Section: Introductionmentioning

confidence: 99%

Resonance Detection Strategy for Multi-Parallel Inverter-Based Grid-Connected Renewable Power System Using Cascaded SOGI-FLL

et al. 2019

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The increasing use of multi-parallel grid-connected inverters introduces both high-quality and high-capacity power, while it tends to cause a resonance instability problem. A resonance damper can virtualize a resistor at resonant frequency to suppress the instability effectively, but the resonant frequency should be detected primarily. However, the resonant current or voltage is severely distorted and oscillating, which will lead to the resonant frequency extraction being more difficult. To address it, this paper proposes a resonance detection strategy based on the cascaded second-order generalized integrators (SOGI) and the normalized frequency locked loop (FLL). The cascaded structure ensures the accuracy by completely filtering the fundamental component from the detected voltage or current, and the normalization accelerates the frequency detection. The proposed method can be used as a crucial unit of the resonance damping controller. Finally, the performance of the proposed method is verified by the MATLAB-based simulation and Hardware-in-the-Loop (HIL)-based emulation results.

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“…To reduce the effect of harmonic distortion and unbalanced voltages in the power grid, in addition to the above methods, the methods based on the coordinate transformation technique also have been developed. The phaselocked loop (PLL) based on a synchronous reference frame (SRF) is a standard PLL that is commonly used in a power grid with a balanced voltage and without any harmonic distortion [20], [21]. However, for a power grid with the harmonic distortion or unbalanced voltages, the performance and ability of SRF-PLL deteriorate [22].…”

Section: Introductionmentioning

confidence: 99%

Mitigation of Background Harmonics Effect on MMC Controller Based on a Novel Coordinate Transformation Technique

et al. 2019

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With the increasing numbers of high-voltage direct current transmission (HVDC) projects based on the modular multilevel converter (MMC), the power quality of the grid-connected MMC has drawn attention. By using peripheral filtering equipment to mitigate the background harmonic effect on MMC leads to several numbers of problems, e.g., high costs, difficulty in parameter tuning, the resonance problem, etc. Therefore, this paper focuses on the mitigation of harmonic pollution for the MMC controller without filters. Based on the multi-layer coordinate transformation structures, a novel nested decoupled synchronous reference frame (NDSRF) transformation technique is presented to attain the harmonics compensation in the coordinate transformation process. Besides, analyses of the proposed NDSRF coordinate transformation technique, including harmonics transfer rules and harmonics rejection principles, are further given in the time domain. Furthermore, to reduce the harmonic content of MMC output voltages in case of a power grid with serious harmonic pollution, the harmonic resistant MMC controller based on the NDSRF technique is proposed. Finally, the simulation results are demonstrated to validate the background harmonic suppression function of the harmonic resistant MMC controller based on the NDSRF transformation technique. INDEX TERMS MMC, power quality, d-q decoupled controller, harmonic transfer, coordinate transformation.

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A Study on Three-Phase FLLs

Cited by 95 publications

References 22 publications

To study unplanned islanding transient response of microgrid by implementing MSOG and SRF‐PLL based hierarchical control in the presence of non‐linear loads

To study unplanned islanding transient response of microgrid by implementing MSOG and SRF‐PLL based hierarchical control in the presence of non‐linear loads

Resonance Detection Strategy for Multi-Parallel Inverter-Based Grid-Connected Renewable Power System Using Cascaded SOGI-FLL

Mitigation of Background Harmonics Effect on MMC Controller Based on a Novel Coordinate Transformation Technique

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