| 摘要 |
<p>U. S. Ser. No. 934,65 MULTI MODE CONTROL SYSTEM FOR WIND TURBINES A multi-mode electronic wind turbine control system establishes a reference blade angle for a two-bladed, horizontal axis, variable pitch wind turbine rotor, the blade angle being regulated by a hydraulic pitch change mechanism. The rotor, via appropriate shafts and a gearbox, is coupled to a synchronous generator to produce electrical energy which is fed to a power utility grid. The control system provides closed loop pitch control for rotor acceleration rate during start-up, for rotor deceleration rate during shutdown, for speed control when the synchronous generator is off-line, and for power control when the synchronous generator is on-line. A single control integrator is used for all closed loop operating modes, with a rate limiter circuit in front of the control integrator to prevent integrator overtravel. The integrator has maximum and minimum blade angle stops, the minimum stop being variable as a function of rotor speed and wind speed. When on-line, power control is provided by a unique shaft torque control using proportional plus integral plus derivative controls in combination. H893-CC</p> |
