A Nonlinear Adaptive Synchronization Techniquefor Grid-Connected Distributed Energy Sources

This letter introduces a new adaptive notch filtering (ANF) approach as a powerful tool for synchronization of converter-interfaced distributed generation systems that can potentially stimulate much interest in the field and provide improvement solutions for both grid-connected and stand-alone (islanding operation) modes of micro-grids. The proposed technique is simple and offers a high degree of immunity and insensitivity to power system disturbances, harmonics and other types of pollution that exist in the grid signal. A modified structure of the ANF-based synchronization technique is capable of decomposing three-phase quantities into symmetrical components, extracting harmonics, tracking the frequency variations, and providing means for voltage regulation and reactive power control. A prominent advantage of the proposed scheme is that it does not require a phase-locked loop for the synchronization. In addition, this very simple and very powerful power signal processor will simplify the control issues currently challenging the integration of distributed energy technologies onto the electricity grid. All converter-interfaced equipment, such as flexible AC transmission systems, custom power controllers, and active power filters, will benefit from this technique. Theoretical analysis is presented and the performance of the method is evaluated through simulation.

[1]  P. Mehta,et al.  Active power filters: a review , 2000 .

[2]  D. G. Holmes,et al.  Stationary frame harmonic reference generation for active filter systems , 2002 .

[3]  J. Svensson,et al.  Tuning software phase-locked loop for series-connected converters , 2005, IEEE Transactions on Power Delivery.

[4]  Hirofumi Akagi,et al.  Instantaneous Reactive Power Compensators Comprising Switching Devices without Energy Storage Components , 1984, IEEE Transactions on Industry Applications.

[5]  Yukihiko Sato,et al.  A new control strategy for voltage type PWM rectifiers to realise zero steady-state control error in input current , 1997, IAS '97. Conference Record of the 1997 IEEE Industry Applications Conference Thirty-Second IAS Annual Meeting.

[6]  M.R. Iravani,et al.  A method for synchronization of power electronic converters in polluted and variable-frequency environments , 2004, IEEE Transactions on Power Systems.

[7]  V. Blasko,et al.  Operation of a phase locked loop system under distorted utility conditions , 1997 .

[8]  T. Tanaka,et al.  A new definition of instantaneous active-reactive current and power based on instantaneous space vectors on polar coordinates in three-phase circuits , 1996 .

[9]  M.R. Iravani,et al.  A signal Processing system for extraction of harmonics and reactive current of single-phase systems , 2004, IEEE Transactions on Power Delivery.

[10]  M. El-Habrouk,et al.  Design and implementation of a modified Fourier analysis harmonic current computation technique for power active filters using DSPs , 2001 .

[11]  J. Svensson.  Synchronisation methods for grid-connected voltage source converters , 2001 .

[12]  Jul-Ki Seok,et al.  Control of series active power filters compensating for source voltage unbalance and current harmonics , 2004, IEEE Transactions on Industrial Electronics.

[13]  Reza Iravani,et al.  A unified dynamic model and control for the voltage-sourced converter under unbalanced grid conditions , 2006 .

[14]  Dragan Jovcic,et al.  Phase locked loop system for FACTS , 2003 .

[15]  B.P. McGrath,et al.  Power converter line synchronization using a discrete Fourier transform (DFT) based on a variable sample rate , 2005, IEEE Transactions on Power Electronics.

[16]  Masoud Karimi-Ghartemani,et al.  A novel three-phase magnitude-phase-locked loop system , 2006, IEEE Transactions on Circuits and Systems I: Regular Papers.

[17]  D. Boroyevich,et al.  Decoupled Double Synchronous Reference Frame PLL for Power Converters Control , 2007, IEEE Transactions on Power Electronics.

[18]  Frede Blaabjerg,et al.  Overview of Control and Grid Synchronization for Distributed Power Generation Systems , 2006, IEEE Transactions on Industrial Electronics.

[19]  K. Nam,et al.  Instantaneous phase-angle estimation algorithm under unbalanced voltage-sag conditions , 2000 .

[20]  Alireza R. Bakhshai,et al.  Estimation of $n$ Frequencies Using Adaptive Notch Filter , 2007, IEEE Transactions on Circuits and Systems II: Express Briefs.

[21]  Se-Kyo Chung,et al.  A phase tracking system for three phase utility interface inverters , 2000 .

[22]  Alireza R. Bakhshai,et al.  An adaptive notch filter for frequency estimation of a periodic signal , 2004, IEEE Transactions on Automatic Control.

[23]  F. Blaabjerg,et al.  A novel control algorithm for static series compensators by use of PQR instantaneous power theory , 2004, IEEE Transactions on Power Electronics.

[24]  G. C. Paap,et al.  Symmetrical components in the time domain and their application to power network calculations , 2000 .

[25]  Kamal Al-Haddad,et al.  A review of active filters for power quality improvement , 1999, IEEE Trans. Ind. Electron..

[26]  Alireza R. Bakhshai,et al.  Time-Domain Signal Analysis Using Adaptive Notch Filter , 2007, IEEE Transactions on Signal Processing.

[27]  M.B. Payan,et al.  Reference current computation methods for active power filters: accuracy assessment in the frequency domain , 2005, IEEE Transactions on Power Electronics.