Enhanced control of DFIG-used back-to-back PWM VSC under unbalanced grid voltage conditions
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This paper presents a unified positive-and negative-sequence dual-dq dynamic model of wind-turbine driven doublyfed induction generator (DFIG) under unbalanced grid voltage conditions. Strategies for enhanced control and operation of a DFIG-used back-to-back (BTB) PWM voltage source converter (VSC) are proposed. The modified control design for the grid-side converter in the stationary αβ frames diminishes the amplitude of DC-link voltage ripples of twice the grid frequency, and the two proposed control targets for the rotor-side converter are alternatively achieved, which, as a result, improve the fault-ride through (FRT) capability of the DFIG based wind power generation systems during unbalanced network supply. A complete unbalanced control scheme with both grid-and rotor-side converters included is designed. Finally, simulation was carried out on a 1.5 MW wind-turbine driven DFIG system and the validity of the developed unified model and the feasibility of the proposed control strategies are all confirmed by the simulated results.
Key wordsUnbalanced grid voltage Doubly-fed induction generator (DFIG) Back-to-back (BTB) Fault-ride through (FRT) Voltage source converter (VSC)
CLC numberTM315 TM614
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- Hu, J.B., He, Y.K., 2007. Modeling and control of grid-connected voltage sourced converter under generalized unbalanced operation conditions. Submitted to IEEE Trans. on Energy Conv., under review.Google Scholar
- Idsoc Nass, B., Undeland, T., Gjengedal, T., 2002. Methods for Reduction of Voltage Unbalance in Weak Grids Connected to Wind Plants. IEEE Workshop on Wind Power and the Impacts on Power Systems. Norway.Google Scholar
- Morren, J., de Haan, S.W.H., Bauser, P., Pierik, J.T.G., 2003. Comparison of Complete and Reduced Models of a Wind Turbine Using Doubly-Fed Induction Generator. Proc. 10th European Conference on Power Electronics and Applications. Toulouse.Google Scholar
- National Grid Transco, 2004. Appendix 1: Extracts from the Grid Code-Connection Conditions. Http://www.nationalgrid.comGoogle Scholar
- Pena, R., Clar, J.C., Asher, G.M., 1996. Doubly fed induction generator using back-to-back PWM converter and its application to variable-speed wind-energy generation. IEE Proc. B, 143(3):231–241.Google Scholar
- Yuan, X., Merk, W., Stemmler, H., Allmeling, J., 2002. Stationary-frame generalized integrators for current control of active power filters with zero steady-state error for current harmonics of concern current under unbalanced and distorted operating conditions. IEEE Trans. on Ind. Appl., 38(2):523–532. [doi:10.1109/28.993175]CrossRefGoogle Scholar