Frequency-Adaptive Stationary-Reference-Frame Grid Voltage Sequence Detector for Distributed Generation Systems

This paper proposes a stationary-frame sequence detector (SFSD) structure for determining the positive sequence in three-phase systems. The structure includes the use of the Clarke transformation and moving average filters (MAFs). The positive-sequence phase angle can be obtained from the alpha-beta components; however, such a detection becomes inaccurate if the grid voltages are unbalanced and/or distorted. The MAF is used to filter the nonideal components. Performance of the MAF is analyzed mathematically for a proper selection of the window width of the optimal filter in this application. The time delay introduced by MAFs is constant and known; hence, this may be compensated. The proposed detector structure allows fast detection of the grid voltage positive sequence (within one grid voltage cycle). The MAF completely eliminates any oscillation multiple of the frequency for which it is designed; thus, this algorithm can overcome the presence of imbalances or harmonics in the electrical grid. Furthermore, it includes a simple frequency estimator that makes the SFSD frequency adaptive and is capable of operating under large frequency changes. The entire SFSD is verified through simulation and experiment, showing very good performance even under several extreme grid voltage conditions.

[1]  Gerardo Escobar,et al.  Fixed-Reference-Frame Phase-Locked Loop for Grid Synchronization Under Unbalanced Operation , 2011, IEEE Transactions on Industrial Electronics.

[2]  L. Asnin,et al.  Comparative characteristics of main methods for dynamic estimation of frequency and magnitude parameters in power systems , 2002, The 22nd Convention on Electrical and Electronics Engineers in Israel, 2002..

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

[4]  C. W. Liu,et al.  A Precise Calculation of Power System Frequency , 2001, IEEE Power Engineering Review.

[5]  M.B. Duric,et al.  Frequency measurement in power networks in the presence of harmonics using fourier and zero crossing technique , 2005, 2005 IEEE Russia Power Tech.

[6]  Leonardo A. B. Tôrres,et al.  Comparison of Three Single-Phase PLL Algorithms for UPS Applications , 2008, IEEE Transactions on Industrial Electronics.

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

[8]  J. Doval-Gandoy,et al.  A Generic Open-Loop Algorithm for Three-Phase Grid Voltage/Current Synchronization With Particular Reference to Phase, Frequency, and Amplitude Estimation , 2009, IEEE Transactions on Power Electronics.

[9]  F. Blaabjerg,et al.  Advanced Grid Synchronization System for Power Converters under Unbalanced and Distorted Operating Conditions , 2006, IECON 2006 - 32nd Annual Conference on IEEE Industrial Electronics.

[10]  Humberto Pinheiro,et al.  New Synchronization Method For Three-phase Three-wire Pwm Converters Under Unbalanced And Distorted Grid Voltages , 2006 .

[11]  Bimal K. Bose,et al.  A Digital PLL Scheme for Three-Phase System Using Modified Synchronous Reference Frame , 2010, IEEE Transactions on Industrial Electronics.

[12]  M.R. Iravani,et al.  Estimation of frequency and its rate of change for applications in power systems , 2004, IEEE Transactions on Power Delivery.

[13]  P. Djurić,et al.  Frequency tracking in power networks in the presence of harmonics , 1993 .

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

[15]  M. R. Iravani,et al.  A Nonlinear Adaptive Filter for Online Signal Analysis in Power Systems: Applications , 2002, IEEE Power Engineering Review.

[16]  Alireza R. Bakhshai,et al.  Estimation of Power System Frequency Using Adaptive Notch Filter , 2005, 2005 IEEE Instrumentationand Measurement Technology Conference Proceedings.

[17]  Aurobinda Routray,et al.  A novel Kalman filter for frequency estimation of distorted signals in power systems , 2002, IEEE Trans. Instrum. Meas..

[18]  David W. P. Thomas,et al.  Evaluation of frequency tracking methods , 2001 .

[19]  Abdellatif Miraoui,et al.  Current Harmonic Compensation by a Single-Phase Shunt Active Power Filter Controlled by Adaptive Neural Filtering , 2009, IEEE Transactions on Industrial Electronics.

[20]  Seppo J. Ovaska,et al.  Digital Filtering for Robust 50/ Zero-Cros sing Detectors , 1996 .

[21]  Vinod John,et al.  A Method to Improve PLL Performance Under Abnormal Grid Conditions , 2007 .

[22]  Mario Rizo,et al.  A Generalized Delayed Signal Cancellation Method for Detecting Fundamental-Frequency Positive-Sequence Three-Phase Signals , 2010, IEEE Transactions on Power Delivery.

[23]  Houshang Karimi,et al.  A magnitude/phase-locked loop system based on estimation of frequency and in-phase/quadrature-phase amplitudes , 2004, IEEE Transactions on Industrial Electronics.

[24]  L. Asnin,et al.  DSP methods for dynamic estimation of frequency and magnitude parameters in power system transients , 2001, 2001 IEEE Porto Power Tech Proceedings (Cat. No.01EX502).

[25]  Stephen J. Finney,et al.  Three-phase phase-lock loop for distorted utilities , 2007 .

[26]  J. Pou,et al.  Control of back-to-back-connected neutral-point-clamped converters in wind mill applications , 2007, 2007 European Conference on Power Electronics and Applications.

[27]  Seppo J. Ovaska,et al.  Noise reduction in zero crossing detection by predictive digital filtering , 1995, IEEE Trans. Ind. Electron..

[28]  J. Pou,et al.  Grid synchronization method based on a quasi-ideal low-pass filter stage and a phase-locked loop , 2008, 2008 IEEE Power Electronics Specialists Conference.

[29]  Francisco A. S. Neves,et al.  A Space-Vector Discrete Fourier Transform for Unbalanced and Distorted Three-Phase Signals , 2010, IEEE Transactions on Industrial Electronics.

[30]  M. Sanaye-Pasand,et al.  Frequency estimation of distorted signals for control and protection of power system , 2004 .

[31]  H.S. Timorabadi,et al.  A Three-Phase Frequency Adaptive Digital Phase Locked Loop for Measurement, Control, and Protection in Power Systems , 2007, 2007 Power Conversion Conference - Nagoya.

[32]  Douglas L. Jones,et al.  Instantaneous frequency estimation using an adaptive short-time Fourier transform , 1995 .

[33]  Ping Lam So,et al.  Model-Based $\hbox{H}_{\infty}$ Control of a Unified Power Quality Conditioner , 2009, IEEE Transactions on Industrial Electronics.

[34]  Mauricio Aredes,et al.  Analysis and Software Implementation of a Robust Synchronizing PLL Circuit Based on the pq Theory , 2006, IEEE Transactions on Industrial Electronics.

[35]  Francisco A. S. Neves,et al.  A Method for Extracting the Fundamental-Frequency Positive-Sequence Voltage Vector Based on Simple Mathematical Transformations , 2008, IEEE Transactions on Industrial Electronics.

[36]  Sergio Busquets-Monge,et al.  Control Strategies Based on Symmetrical Components for Grid-Connected Converters Under Voltage Dips , 2009, IEEE Transactions on Industrial Electronics.

[37]  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.