Variable speed wind turbine
AssigneeUnited Technologies Corporation
InventorsGlidden S. Doman, Joseph M. Kos, Kermit I. Harner, Eugene D. DiValentin, Henry S. Healy
Life of this patent
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Abstract
A variable speed wind turbine includes a frequency converter which converts variable frequency AC from a turbine driven AC generator to fixed frequency AC for delivery to a power grid. The frequency converter is typically an electronic cycloconverter or rectifier-inverter and is also used to control the power flow from the AC generator to the grid which thereby controls the air gap torque between the generator stator and rotor. The turbine speed is maneuvered to increase efficiency by precisely controlling the air gap torque according to a schedule defining sensed generator speed versus sensed generated power.
Claims8
A variable speed wind turbine system having an optimum power coefficient versus velocity ratio performance curve, comprising:
- a turbine rotor shaft with a hub at one end with at least one blade attached to the hub;
- a gearbox, having a low speed side thereof attached to the other end of the turbine rotor shaft;
- an AC generator, having a generator rotor shaft attached to a high speed side of the gearbox, the generator providing variable frequency AC at a power output line thereof;
- sensing means, for sensing generator speed and generator electrical power output and for providing sensed signals indicative thereof;
- a variable speed wind turbine controller, responsive to the sensed signals indicative of generator speed and generator electrical power output, for providing a generator torque command signal for commanding maneuvers of the generator speed according to a function defining generator speed versus generator electrical power output which manuevers tend to cause the wind turbine to operate substantially on the wind turbine power coefficient versus velocity ratio optimum performance curve substantially at the peak thereof;
- and
- a frequency converter, electrically connected to the generator power output line and responsive to the generator output AC for converting the variable frequency AC to constant frequency AC, the frequency converter responsive to the generator torque command signal for controlling the magnitude of power flow through the converter, thereby effecting control of the generator torque.
Dependencies are inferred from the claim text.