With energy and environment issues increasingly serious, as the current largest scale developmental renewable energy and with the most commercial prospects, wind power has been getting more and more concern and attention by all the countries in the world. In recent years wind power has obtained vigorous expansion, especially doubly-fed wind power system based on variable-speed constant-frequency (VSCF) technology has been one of the main stream models and the control technology of DFIG (Doubly-fed induction...