scholarly journals An Adaptive Frequency Phase-Locked Loop Based on a Third Order Generalized Integrator

Energies ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 309 ◽  
Author(s):  
Heng Du ◽  
Qiuye Sun ◽  
Qifu Cheng ◽  
Dazhong Ma ◽  
Xu Wang
Keyword(s):  
Single Phase ◽  
Power Grid ◽  
Phase Locked Loop ◽  
Frequency Change ◽  
Third Order ◽  
Vector Method ◽  
Grid Voltage ◽  
Dc Offset ◽  
Voltage Frequency ◽  
Frequency Changes

In this paper, the basic principle and characteristics of a phase-locked loop (PLL) in a single phase grid-connected system are analyzed, and this paper introduces one type virtual orthogonal voltage vector method based on a third order generalized integrator (TOGI) to construct an alpha and beta static coordinate system. The TOGI structure can eliminate the DC offset in a voltage signal or zero offset in the sampling process, and ensure the amplitude of the virtual orthogonal signal is consistent. At the same time, the adaptive frequency estimation unit is introduced, which can effectively deal with the power grid voltage frequency changes and ensure the accuracy of PLL. MATLAB (R2012a, MathWorks, Natick, MA, USA) is used to simulate the variation of power grid voltage frequency, DC component injection, harmonics injection and other parameters, and the performance of PLL is adequately verified. In addition, a 5kW single-phase energy router experimental platform is built to verify the proposed PLL. The experimental results show that the PLL can well track the frequency change of the grid voltage and eliminate the DC offset, so as to achieve accurate phase tracking.

scholarly journals DC offset rejection in a frequency-fixed second-order generalized integrator-based phase-locked loop for single-phase grid-connected applications

2022 ◽  
Vol 7 (1) ◽  
Author(s):  
Issam A. Smadi ◽  
Bayan H. Bany Fawaz
Keyword(s):  
Single Phase ◽  
Dynamic Performance ◽  
Phase Error ◽  
Phase Locked Loop ◽  
Second Order ◽  
Frequency Variation ◽  
Grid Voltage ◽  
Dc Offset ◽  
Grid Synchronization ◽  
Grid Connected Converters

AbstractFast and accurate monitoring of the phase, amplitude, and frequency of the grid voltage is essential for single-phase grid-connected converters. The presence of DC offset in the grid voltage is detrimental to not only grid synchronization but also the closed-loop stability of the grid-connected converters. In this paper, a new synchronization method to mitigate the effect of DC offset is presented using arbitrarily delayed signal cancelation (ADSC) in a second-order generalized integrator (SOGI) phase-locked loop (PLL). A frequency-fixed SOGI-based PLL (FFSOGI-PLL) is adopted to ensure better stability and to reduce the complexity compared with other SOGI-based PLLs. A small-signal model of the proposed PLL is derived for the systematic design of proportional-integral (PI) controller gains. The effects of frequency variation and ADSC on the proposed PLL are considered, and correction methods are adopted to accurately estimate grid information. The simulation results are presented, along with comparisons to other single-phase PLLs in terms of settling time, peak frequency, and phase error to validate the proposed PLL. The dynamic performance of the proposed PLL is also experimentally validated. Overall, the proposed PLL has the fastest transient response and better dynamic performance than the other PLLs for almost all performance indices, offering an improved solution for precise grid synchronization in single-phase applications.

A cogeneration scheme with biogas and improvement of frequency stability using inertia based control in AC microgrid

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Subhendu Bikash Santra ◽  
Babatunde Tolu Ogungbe
Keyword(s):  
Large Scale ◽  
Frequency Control ◽  
Power Grid ◽  
Renewable Energy Sources ◽  
Rate Of Change ◽  
Biogas Plant ◽  
Frequency Change ◽  
Power Requirement ◽  
Frequency Changes ◽  
Ac Microgrid

Abstract Currently, penetration of the renewable energy sources (RES) like solar photovoltaic (PV) panels, wind turbine-based plants is increasing in the conventional power grid to combat pollution, global warming, and to enhance energy sustainability. Fast power electronic converters are necessary to extract power from these sources which do not have any inertia. When more renewable sources are connected to the power grid, it reduces the effective system inertia which results in unacceptable grid frequency changes for any transient. This leads to frequent tripping, cascading fault, and instability of the overall system which can create large-scale blackouts. This work is related to the generation of physical inertia through the biogas plant and emulates inertia from the dc-link capacitor to control the rate of change of frequency (RoCoF) under abrupt load change. The stored energy in a biogas plant and dc-link capacitor in an AC microgrid (MG) can support momentary power requirement which improves the transient performance of grid frequency under unavailability of PV power. A storage system can help to compensate for abrupt frequency change during transient but due to its higher cost and relatively lesser lifetime, these systems can’t be relied upon in the long run. The proposed scheme of cogeneration and frequency control can provide better performance which is simulated in MATLAB 2013 (b). The control system is implemented in hardware using NI-cRiO 9082 in 500 W AC MG which shows 53.57% improvement in RoCoF which complies with the requirement of IEEE/IEC 60255-118-1.

Single‐phase phase locked loop with DC offset and noise rejection for photovoltaic inverters

2014 ◽  
Vol 7 (9) ◽  
pp. 2288-2299 ◽  
Author(s):  
Slobodan Lubura ◽  
Milomir Šoja ◽  
Srd‐an Lale ◽  
Marko Ikić
Keyword(s):  
Single Phase ◽  
Phase Locked Loop ◽  
Dc Offset ◽  
Noise Rejection ◽  
Phase Phase

scholarly journals An Effective Solution to Eliminate DC-Offset for Extracting the Phase and Frequency of Grid Voltage

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Fehmi Sevilmiş ◽  
Hulusi Karaca
Keyword(s):  
Dynamic Performance ◽  
Phase Locked Loop ◽  
Experimental Results ◽  
Effective Solution ◽  
Control Loop ◽  
Slow Dynamic ◽  
Grid Voltage ◽  
Dc Offset

Recently, several approaches with the ability to reject the DC-offset in phase locked loop (PLL) methods have been developed. These approaches include different filtering structures which can be classified into two categories: prefiltering before the PLL input and in-loop filtering in the PLL control loop. As highlighted in the literature, the DC-offset rejection methods based on in-loop filtering have received less attention due to their slow dynamic performance. Therefore, this paper proposes an alternative DC-offset rejection technique as in-loop filtering of the PLL. The effectiveness of the proposed PLL is confirmed by simulation and experimental results.

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