Noninvasive Online Parametric Identification of Three-Phase AC Power Impedances to Assess the Stability of Grid-Tied Power Electronic Inverters in LV Networks

This paper presents a noninvasive online parametric identification of three-phase ac power impedances to assess small-signal stability of grid-tied inverter systems by using well-known impedance-ratio-based stability criteria. The identification technique is integrated into the control of an existing grid-tied inverter for the estimation of wide bandwidth ac grid impedances, on top of its original power conversion function. This is accomplished in practice by injecting a short-time small-signal pseudorandom binary sequence (PRBS), a digital approximation of white noise which is wide bandwidth in nature, on the inverter control loop so that all frequencies of interest at the impedance measurement point can be excited at once. Then, digital processing is performed in the integrated control platform where the parametric ac grid impedance is extracted from the measurement of voltage and current over the length of PRBS injection. Moreover, a procedure on how to identify the output impedance of the inverter is deployed so that the parametric source and load impedances can be used to verify the system stability by means of the generalized Nyquist stability criterion. The technique is validated via hardware-in-the-loop real-time simulation. This paper focuses on the identification of balanced three-phase ac impedances in dq reference frame and a dq diagonal-dominant stability analysis which is typical of low-voltage distribution grids.

[1]  E. C. Levy Complex-curve fitting , 1959, IRE Transactions on Automatic Control.

[2]  R. D. Middlebrook,et al.  Input filter considerations in design and application of switching regulators. , 1976 .

[3]  Lennart Ljung,et al.  System Identification: Theory for the User , 1987 .

[4]  Robert W. Erickson,et al.  Fundamentals of Power Electronics , 2001 .

[5]  Mark Sumner,et al.  A technique for power supply harmonic impedance estimation using a controlled voltage disturbance , 2002 .

[6]  D. Maksimovic,et al.  System identification of power converters with digital control through cross-correlation methods , 2005, IEEE Transactions on Power Electronics.

[7]  C. Dufour,et al.  Hardware-In-the-Loop Simulation of Power Drives with RT-LAB , 2005, 2005 International Conference on Power Electronics and Drives Systems.

[8]  Zbigniew Staroszczyk,et al.  A method for real-time, wide-band identification of the source impedance in power systems , 2005, IEEE Transactions on Instrumentation and Measurement.

[9]  M. Liserre,et al.  Stability of photovoltaic and wind turbine grid-connected inverters for a large set of grid impedance values , 2006, IEEE Transactions on Power Electronics.

[10]  Lennart Harnefors,et al.  Modeling of Three-Phase Dynamic Systems Using Complex Transfer Functions and Transfer Matrices , 2007, IEEE Transactions on Industrial Electronics.

[11]  Jian Sun,et al.  Input Impedance Modeling and Analysis of Line-Commutated Rectifiers , 2007, 2007 IEEE Power Electronics Specialists Conference.

[12]  Jian Sun,et al.  Small-Signal Methods for AC Distributed Power Systems–A Review , 2009, IEEE Transactions on Power Electronics.

[13]  E. Santi,et al.  Online Monitoring of Network Impedances Using Digital Network Analyzer Techniques , 2009, 2009 Twenty-Fourth Annual IEEE Applied Power Electronics Conference and Exposition.

[14]  Jing Huang,et al.  Small-Signal Impedance Measurement of Power-Electronics-Based AC Power Systems Using Line-to-Line Current Injection , 2009, IEEE Transactions on Power Electronics.

[15]  M. Liserre,et al.  Future Energy Systems: Integrating Renewable Energy Sources into the Smart Power Grid Through Industrial Electronics , 2010, IEEE Industrial Electronics Magazine.

[16]  Dushan Boroyevich,et al.  On the Ac stability of high power factor three-phase rectifiers , 2010, 2010 IEEE Energy Conversion Congress and Exposition.

[17]  Jian Sun,et al.  Impedance-Based Stability Criterion for Grid-Connected Inverters , 2011, IEEE Transactions on Power Electronics.

[18]  Enrico Santi,et al.  Wide bandwidth system identification of AC system impedances by applying pertubations to an existing converter , 2011, 2011 IEEE Energy Conversion Congress and Exposition.

[19]  Dushan Boroyevich,et al.  An algorithm and implementation system for measuring impedance in the D-Q domain , 2011, 2011 IEEE Energy Conversion Congress and Exposition.

[20]  Alex Simpkins,et al.  System Identification: Theory for the User, 2nd Edition (Ljung, L.; 1999) [On the Shelf] , 2012, IEEE Robotics & Automation Magazine.

[21]  E. Santi,et al.  Wide bandwidth three-phase impedance identification using existing power electronics inverter , 2013, 2013 Twenty-Eighth Annual IEEE Applied Power Electronics Conference and Exposition (APEC).

[22]  E. Santi,et al.  Positive Feedforward Control of Three-Phase Voltage Source Inverter for DC Input Bus Stabilization With Experimental Validation , 2013, IEEE Transactions on Industry Applications.

[23]  Bimal K. Bose,et al.  Global Energy Scenario and Impact of Power Electronics in 21st Century , 2013, IEEE Transactions on Industrial Electronics.

[24]  Jian Sun,et al.  Broadband methods for online grid impedance measurement , 2013, 2013 IEEE Energy Conversion Congress and Exposition.

[25]  Enrico Santi,et al.  Comprehensive Review of Stability Criteria for DC Power Distribution Systems , 2014, IEEE Transactions on Industry Applications.

[26]  Jian Sun,et al.  Online Grid Impedance Measurement Using Discrete-Interval Binary Sequence Injection , 2013, IEEE Journal of Emerging and Selected Topics in Power Electronics.

[27]  Bo Wen,et al.  Modeling the output impedance of three-phase uninterruptible power supply in D-Q frame , 2014, 2014 IEEE Energy Conversion Congress and Exposition (ECCE).

[28]  Jian Sun,et al.  Impedance Modeling and Analysis of Grid-Connected Voltage-Source Converters , 2014, IEEE Transactions on Power Electronics.

[29]  Peter Schegner,et al.  Measurement of network harmonic impedance in presence of electronic equipment , 2015, 2015 IEEE International Workshop on Applied Measurements for Power Systems (AMPS).

[30]  Friedrich W. Fuchs,et al.  Measurement results and performance analysis of the grid impedance in different low voltage grids for a wide frequency band to support grid integration of renewables , 2015, 2015 IEEE Energy Conversion Congress and Exposition (ECCE).

[31]  Bo Wen,et al.  Small-Signal Stability Analysis of Three-Phase AC Systems in the Presence of Constant Power Loads Based on Measured d-q Frame Impedances , 2015, IEEE Transactions on Power Electronics.

[32]  Dushan Boroyevich,et al.  Wide-bandwidth Identification of small-signal dq impedances of ac power systems via single-phase series voltage injection , 2015, 2015 17th European Conference on Power Electronics and Applications (EPE'15 ECCE-Europe).

[33]  Friedrich W. Fuchs,et al.  Modeling of inverter output impedance for stability analysis in combination with measured grid impedances , 2015, 2015 IEEE 6th International Symposium on Power Electronics for Distributed Generation Systems (PEDG).

[34]  Bo Wen,et al.  D-Q impedance specification for balanced three-phase AC distributed power system , 2015, 2015 IEEE Applied Power Electronics Conference and Exposition (APEC).

[35]  Antonello Monti,et al.  Online wideband identification of single-phase AC power grid impedances using an existing grid-tied power electronic inverter , 2015, 2015 IEEE 6th International Symposium on Power Electronics for Distributed Generation Systems (PEDG).

[36]  Jing Wang,et al.  Design of a Generalized Control Algorithm for Parallel Inverters for Smooth Microgrid Transition Operation , 2015, IEEE Transactions on Industrial Electronics.

[37]  Bo Wen,et al.  Analysis of D-Q Small-Signal Impedance of Grid-Tied Inverters , 2016, IEEE Transactions on Power Electronics.

[38]  Christian Breyer,et al.  Integrated renewable energy based power system for Europe, Eurasia and MENA regions , 2016, 2016 International Energy and Sustainability Conference (IESC).

[39]  Roinila Tomi,et al.  Impedance measurement of three phase systems in DQ-domain: Applying MIMO-identification techniques , 2016 .

[40]  Detlef Schulz,et al.  Novel grid impedance measurement setups in electrical power systems , 2016, 2016 IEEE International Workshop on Applied Measurements for Power Systems (AMPS).

[41]  Antonello Monti,et al.  Online wideband identification of three-phase AC power grid impedances using an existing grid-tied power electronic inverter , 2016, 2016 IEEE 17th Workshop on Control and Modeling for Power Electronics (COMPEL).

[42]  Johann W. Kolar,et al.  Protection of MV Converters in the Grid: The Case of MV/LV Solid-State Transformers , 2017, IEEE Journal of Emerging and Selected Topics in Power Electronics.

[43]  Antonello Monti,et al.  Online Parametric Identification of Power Impedances to Improve Stability and Accuracy of Power Hardware-in-the-Loop Simulations , 2017, IEEE Transactions on Instrumentation and Measurement.

[44]  Bo Wen,et al.  Inverse Nyquist Stability Criterion for Grid-Tied Inverters , 2017, IEEE Transactions on Power Electronics.