Dynamic model and control of the NPC-based back-to-back HVDC system

This paper presents a comprehensive model of the Back-to-Back (BtB) HVDC system based on the three-level Neutral-Point Diode Clamped (NPC) converter. Based on the developed model, a systematic design procedure for i) the ac-side controllers, ii) the voltage balancer of the dc-side capacitors, and iii) the net dc-bus voltage controller, are presented. The model is developed based on the generalized state-space averaging method and the principle of power balance. The developed model precisely describes the system dynamics if the ac grids are strongly or moderately stiff, and offers acceptable precision otherwise. The averaged nature of the model inherently renders itself for analysis in the SIMULINK/MATLAB environment, and thus provides a computationally efficient tool for the design and the performance evaluation of the control. The accuracy of the developed model and the controls are validated by comparing the results from MATLAB/SIMULINK with those obtained from the exact switching model of the system, based on digital time-domain simulation studies, using the PSCAD/EMTDC software package.

[1]  Mark Sumner,et al.  Multi-level converters: a real solution to high voltage drives? , 1997 .

[2]  Lie Xu,et al.  Topologies for VSC transmission , 2001 .

[3]  G. Asplund.  Application of HVDC Light to power system enhancement , 2000, 2000 IEEE Power Engineering Society Winter Meeting. Conference Proceedings (Cat. No.00CH37077).

[4]  A. Petersson,et al.  Eagle Pass back-to-back tie: a dual purpose application of voltage source converter technology , 2001, 2001 Power Engineering Society Summer Meeting. Conference Proceedings (Cat. No.01CH37262).

[5]  A. Lindberg,et al.  Pwm And Control Of Three Level Voltage Source Converters In An Hvdc Back-to-back Station , 2002 .

[6]  M. B. Brennen,et al.  Vector analysis and control of advanced static VAr compensators , 1991 .

[7]  A. Lindberg,et al.  PWM and control of three level voltage source back-to-back station , 1996 .

[8]  Hirofumi Akagi,et al.  A New Neutral-Point-Clamped PWM Inverter , 1981, IEEE Transactions on Industry Applications.

[9]  R. Iravani,et al.  A generalized state-space averaged model of the three-level NPC converter for systematic DC-voltage-balancer and current-controller design , 2005, IEEE Transactions on Power Delivery.

[10]  N. Jenkins,et al.  Mathematical models of a three-level advanced static VAr compensator , 1997 .

[11]  Makoto Hagiwara,et al.  Performance of a self-commutated BTB HVDC link system under a single-line-to-ground fault condition , 2003 .

[12]  Laszlo Gyugyi,et al.  Understanding FACTS: Concepts and Technology of Flexible AC Transmission Systems , 1999 .

[13]  G. Lipphardt.  Using a three-level GTO voltage source inverter in a HVDC transmission system , 2002 .

[14]  Jorge Pontt,et al.  "Novel 20 MW downhill conveyor system using three-level converters" , 2001, Conference Record of the 2001 IEEE Industry Applications Conference. 36th IAS Annual Meeting (Cat. No.01CH37248).

[15]  M. Noroozian,et al.  The Potential Use of Voltage-Sourced Converter-Based Back-to-Back Tie in Load Restorations , 2002, IEEE Power Engineering Review.

[16]  Lie Xu,et al.  Topology for VSC transmission , 2002 .

[17]  Fang Zheng Peng,et al.  Multilevel converters-a new breed of power converters , 1995, IAS '95. Conference Record of the 1995 IEEE Industry Applications Conference Thirtieth IAS Annual Meeting.