| 摘要 |
<p>38 A windpower system includes a support and a turbine having a shaft rotatively mounted to the support. The turbine has variable pitch blades whose pitch is controlled by the differential motion of a rotary control shaft coaxial with the turbine shaft and the turbine shaft itself so that the blade pitch can be varied by a stationary motor without requiring any slip rings or other such wear-prone couplings. In the event of a power failure, rotary motion of the control shaft is prevented so that the turbine blades are feathered solely due to the force developed by the rotating turbine. Also, if the turbine is used to generate electrical power, an induction generator coupled to the turbine shaft is employed whose shaft speed is indicative of generator output power. Accordingly, generator speed is monitored and used to control the pitch of the turbine blades so as to maintain generator output power at the maximum value when wind speed is below the machine's rated wind speed, and no more than rated output power when wind speed exceeds rated wind speed.</p> |
