The shaft of a wind turbine is connected to the rotor of a three-phase AC generator. The rotor windings, in turn, are connected to the rotor windings of a DC-energized, AC exciter via a differential frequency-converter. A frequency-detector, which monitors the output of the AC generator, is connected...http://www.google.ca/patents/US4400659?utm_source=gb-gplus-sharePatent US4400659 - Methods and apparatus for maximizing and stabilizing electric power derived from wind driven source
