Enhanced Efficacy of Kinetic Power Transform for High-Speed Wind Field

The three-time-scale plant model of a wind power generator, including a wind turbine, a flexible vertical shaft, a Variable Inertia Flywheel (VIF) module, an Active Magnetic Bearing (AMB) unit and the applied wind sequence, is constructed. In order to make the wind power generator be still able to operate as the spindle speed exceeds its rated speed, the VIF is equipped so that the spindle speed can be appropriately slowed down once any stronger wind field is exerted. To prevent any potential damage due to collision by shaft against conventional bearings, the AMB unit is proposed to regulate the shaft position deviation. By singular perturbation order-reduction technique, a lower-order plant model can be established for the synthesis of feedback controller. Two major system parameter uncertainties, an additive uncertainty and a multiplicative uncertainty, are constituted by the wind turbine and the VIF respectively. Frequency Shaping Sliding Mode Control (FSSMC) loop is proposed to account for these uncertainties and suppress the unmodeled higher-order plant dynamics. At last, the efficacy of the FSSMC is verified by intensive computer and experimental simulations for regulation on position deviation of the shaft and counter-balance of unpredictable wind disturbance.

Authors:

• Nan-Chyuan Tsai
• Chao-Wen Chiang
• Bai-Lu Wang

Keywords:

• Sliding Mode Control
• Singular Perturbation
• Variable Inertia Flywheel.

References:

[1] D.-J. Lee, L. Wang, Small-signal stability analysis of an autonomous
hybrid renewable energy power generation/energy storage system part I:
Time-domain simulations, IEEE Transactions on Energy Conversion 23
(908) 311-320.
[2] J. F. Manwell, J. G. McGowan, A. L. Rogers, Wind Energy Explained:
Theory, Design and Application. Chichester, UK, Wiley, 2002.
[3] B. E. Muhando, T. Senjyu, A. Yona, H. Kinjo, T. Funabashi, Regulation
of WTG dynamic response to parameter variations of analytic wind
stochasticity, Wind Energy 11 (908) 133-150.
[4] L. W. Chen, D.-M. Ku, Finite element analysis of natural whirl speeds of
rotating shafts, Computers and Structures 40 (891) 741-747.
[5] K.-K. D. Young, P. V. Kokotovic, V. I. Utkin, Singular Perturbation
Analysis of High-gain Feedback Systems, IEEE Transactions on
Automatic Control 22 (897) 931-938.
[6] A. J. Koshkouei, A. S. I. Zinober, Robust frequency shaping sliding mode
control, in: IEE Proceedings: Control Theory and Applications, Vol. 147,
2000, pp. 312-320.