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.

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.

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.

SUPPRESSING PHASE LOCKED LOOP GAIN FLUCTUATIONS IN WIDEBAND LINEARLY FREQUENCY MODULATED WAVEFORM SYNTHESIZERS

2012 ◽  
Vol 11 (02) ◽  
pp. 1250011
Author(s):  
WEN-QIN WANG
Keyword(s):  
Frequency Band ◽  
System Performance ◽  
Phase Locked Loop ◽  
Experimental Results ◽  
Limiting Factor ◽  
Voltage Controlled Oscillator ◽  
Effective Solution ◽  
Loop Gain ◽  
Compensation Algorithm

Wideband linearly frequency modulated (LFM) signals are required for many communication navigation applications; however, a limiting factor is the presence of frequency nonlinearity which degrades the system performance significantly. The fluctuations of phase locked loop (PLL) loop gain and voltage controlled oscillator (VCO) gain will results in inconsistent frequency nonlinearity performance in the whole frequency band. In this letter, we propose an effective solution by real-timely tuning the phase/frequency detecting current, along with the iterative compensation algorithm. In this way, the frequency nonlinearity is compensated and a wideband LFM waveform synthesizer can be designed. This approach is validated by experimental results.

Experimental and Numerical Analyses of a Head Arm Assembly of a Micro-Drive

2006 ◽  
Vol 326-328 ◽  
pp. 1585-1588
Author(s):  
B.J. Shi ◽  
Dong Wei Shu ◽  
J. Luo ◽  
Q.Y. Ng ◽  
J.H.T. Lau
Keyword(s):  
Finite Element ◽  
Dynamic Properties ◽  
Dynamic Performance ◽  
Hard Disk Drives ◽  
Element Model ◽  
Information Storage ◽  
Experimental Results ◽  
Disk Drives ◽  
Element Simulation ◽  
Important Means

Hard disk drives (HDD) are now the most important means of information storage, and they continue to be made smaller in size, higher in capacity, and lower in cost. The dynamic performance of an HDD has been an increasingly important consideration for its design, as we move forward toward its consumer applications. The dynamic properties of the head arm assembly (HAA) of a micro-drive were investigated using both experimental and numerical techniques. A finite element model for studying the dynamic property of the HAA was created and modified according to the experimental results. Good correlation between the experimental results and those by finite element simulation was achieved.

scholarly journals Optimizing the Spectral Characterisation of a CMYK Printer with Embedded CMY Printer Modelling

2019 ◽  
Vol 9 (24) ◽  
pp. 5308
Author(s):  
Qiang Liu ◽  
Zheng Huang ◽  
Michael R. Pointer ◽  
M. Ronnier Luo
Keyword(s):  
Cellular Structure ◽  
Experimental Results ◽  
Digital Printing ◽  
Input Device ◽  
Effective Solution ◽  
Spectral Accuracy ◽  
Printing Process ◽  
Dark Tone ◽  
Spectral Characterisation

In the digital printing process, reliable colour reproduction is commonly achieved by printer characterisation, which defines the correspondence between the input device control values and the output colour information. The cellular Yule–Nielsen spectral Neugebauer model, together with its variants, is widely adopted in this topic because of its superb colorimetric and spectral accuracy. However, it seems that current studies have neglected an inconspicuous defect in such models when characterising printers equipped with black ink. That is, the cellular structure of these models overemphasises the sampling for dark-tone colours, and thus leads to relatively large errors in light tones. In this paper, taking a CMYK printer as an example, a simple and effective solution is proposed with no need of extra sampling. With the aid of a newly built cellular spectral Neugebauer model for the embedded CMY printer, this approach optimises the printer characterisation for light tones, slightly improves the precision for middle tones while it maintains the accuracy for dark tones. The performance of the proposed method was evaluated with regard to three different kinds of substrates and the experimental results validated its improvement in spectral printer characterisation.

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