Wide bandwidth three-phase impedance identification using existing power electronics inverter

In smart grid applications knowing system impedances over a wide frequency range makes it possible to perform useful diagnostic and prognostic activities related to a number of grid related issues, such as: predicting harmonic propagation, identifying resonances, detecting high impedance faults, identifying voltage distortion, and identifying harmonic polluters. The proposed online monitoring technique leverages wideband impedance identification to enable a number of smart-grid related capabilities, such as health monitoring, active filter re-tuning, and adaptive control of grid-connected switching converters, all of which lead to the improved stability, performance and reliability of smart grid systems. In this paper, a new approach is developed using a power converter to make a wideband three-phase impedance measurement at its interface in addition to providing power generation capability. A small signal white noise injection via a pseudo-random binary sequence (PRBS) is added to the converter's PWM, eliciting a small signal wideband impedance disturbance. Using cross-correlation techniques, the output impedances seen by the converter are constructed.

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

[2]  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.

[3]  W. Xu,et al.  Harmonic impedance measurement using three-phase transients , 1998 .

[4]  Daniel Martin.  Applications of Power Electronic Converter Based Wideband System Identification in Grid Tied AC Power Systems , 2012 .

[5]  H.J. Vermeulen,et al.  A perturbation source for in situ parameter estimation applications , 1994, Proceedings of IECON'94 - 20th Annual Conference of IEEE Industrial Electronics.

[6]  E. Santi,et al.  Improved online identification of switching converters using digital network analyzer techniques , 2008, 2008 IEEE Power Electronics Specialists Conference.

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

[8]  E. Santi,et al.  Auto tuning of digital deadbeat current controller for grid tied inverters using wide bandwidth impedance identification , 2012, 2012 Twenty-Seventh Annual IEEE Applied Power Electronics Conference and Exposition (APEC).

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

[10]  M. Sumner,et al.  Improved Power Quality Control and Intelligent Protection for Grid Connected Power Electronic Converters, using Real Time Parameter Estimation , 2006, Conference Record of the 2006 IEEE Industry Applications Conference Forty-First IAS Annual Meeting.