The usage of squirrel cage induction machines in wind generation is mostly preferred as a generator of choice. The squirrel cage induction machine is reliable, simple, light weight, cheap and requires very less maintenance. At constant frequency the induction generator is connected to the utility. For constant frequency application, the induction generator runs at small value of slip i. e. practically constant speed. The wind turbine works at maximum efficiency only for a small range of wind speed deviation. For variable speed application, an induction generator demands an interface to convert the variable frequency output of the generator to the fixed frequency. This system is discussed using self-excited generator because a simple diode bridge requires performing the ac/dc conversion. The successive dc/ac conversion will be performed using various techniques. The use of a thyristor bridge is accessible for large power conversion and has higher reliability and lower cost. The firing angle of the inverter bridge can be controlled for tracking the optimum power curve of the wind turbine. With only thyristors and diodes used in power conversion, the system can be scaled up to a very high power and high voltage applications.

1. C. F. Wagner, . Self-Excitation of Induction Motors with Series Capacitors. . AIEE Transactions, February 1941, Vol. 60, pp. 1241-1247.
2. E. Muljadi, B. Gregory, and D. Broad . Self-excited Induction Generator for Variable-Speed Wind Turbine Generation. . Power systems World´96 Conference, Las Vegas, Nevada. Alternative Energy Session, September 7-13, 1996, pp. 343-352.
3. T. F. Chan . Self-excited Induction Generators Driven by Regulated and Unregulated Turbines , IEEETransactions on Energy Conversion, June 1996,Vol. 11,No. 2.
4. K. E. Hallenius, P Vas, J. E. Brown. . The Analysis of a Saturated Self-Excited Asynchronous GeneratorIEEETransactions on Energy Conversion, June 1991, Vol. 6,No. 2.
5. Elder, J. M. , Boys, J. T. , Woodward, J. L. : 'The process of self-excitationin induction generators', Proc. IEE, 1983, 130, (2), pp. 103–108
6. Alghuwainem, S. M. : 'Steady-state analysis of an isolated self-excited induction generator driven by regulated and unregulated turbine', IEEE Trans. Energy Convers. , 1999, 14, (3), pp. 718–723
7. Grantham, C. , Sutanto, D. , Mismail, B. : 'Steady-state and transient analysis of self-excited induction generators', IEE Proc. Electric Power Appl. , 1989, 136, (2), pp. 61–68
8. Joshi, D. , Sandhu, K. S. , Soni, M. K. : 'Constant voltage constant frequency operation for a self-excited induction generator', IEEE Trans. Energy Convers. , 2006, 21, (1), pp. 228–234
9. Arrillaga, J. , Watson, D. B. : 'Static power conversion from self-excited induction generators', Proc. IEE, 1978, 125, (8), pp. 743–746
10. Bansal, R. C. : 'Three-phase self-excited induction generators: an overview', IEEE Trans. Energy Convers. , 2005, 20, (2), pp. 292–299
11. Murthy, S. S. , Malik, O. P. , Tandon, A. K. : 'Analysis of self-excited induction generators', Proc. IEE, 1982, 129, (C6), pp. 260–265
12. Boldea, I. , Nasar, S. A. : 'Induction machines handbook' (CRC Press, Boca Raton, 2001)
13. Haque, M. H. : 'A novel method of evaluating performance characteristics of a self-excited induction generator', IEEE Trans. Energy Convers. , 2009, 24, (2), pp. 358–365
14. Levi, E. , Liao, Y. W. : 'An experimental investigation of self-excitation in capacitor excited induction generators', Electr. Power Syst. Res. , 2000, 53, (1), pp. 59–65

Wind Energy Variable Speed Generation System renewable Energy Self Excitation