US 4,348,155 AGranted

Wind turbine blade pitch control system

AssigneeUnited Technologies Corporation

InventorsPhilip E. Barnes, Millard G. Mayo, Robert Sherman

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Abstract

A pitch control system for a multibladed variable pitch wind turbine. Each of the turbine blades is pivotally driven about the longitudinal axis thereof independently of the other blades by at least a pair of hydraulic actuators. The actuators are supplied with pressurized hydraulic fluid from a first source thereof under conditions of normal pitch change adjustment. Under conditions wherein feathering of the blades is required, the actuators are supplied with hydraulic fluid from second sources thereof such that one of the actuators associated with each of the blades is supplied with fluid from one second source and a second actuator is provided with fluid from a redundant second source whereby blade feathering may be effected despite a malfunction of one of the redundant sources or one of the actuators. In one of the two preferred embodiments disclosed, the first and second fluid sources are maintained in mutual communication whereby fluid from the second sources thereof may supplement fluid from the first source under conditions of normal blade pitch adjustment.

Claims19

Dependent claims

A pitch control system for a wind turbine having a plurality of blades, said control system comprising a plurality of hydraulic actuators, each connected to one of said blades and adapted to pivot said blade about the longitudinal axis thereof in blade pitch adjusting and feathering modes of operation;

means in fluid communication with said actuators for selectively distributing hydraulic fluid to said actuators in both pitch adjusting and feathering modes of operation;
first and redundant second sources of pressurized hydraulic fluid in fluid communication with said distributing means for supplying hydraulic fluid thereto for delivery to said actuators;
first means communicating with said first hydraulic fluid source for controlling the introduction of hydraulic fluid from said first source to said distributing means in said blade pitch adjusting mode and second means communicating with said second hydraulic fluid sources for controlling the introduction of hydraulic fluid from said redundant second hydraulic fluid sources in said blade feathering mode such that each of said redundant sources supplies hydraulic fluid to at least a single one of said actuators associated with each of said blades independently of other hydraulic actuators associated therewith whereby each of said redundant second sources of hydraulic fluid is individually capable of powering all of said blades simultaneously in said feather mode of operation.

Dependencies are inferred from the claim text.