Investigation of passive blade cyclic pitch variation using an automatic yaw control system. Final report

Technical Report · Sun Aug 01 00:00:00 EDT 1982

DOI:https://doi.org/10.2172/7097186· OSTI ID:7097186

Hohenemser, K H; Swift, A H.P.

The investigation of passive cyclic pitch variation using an automatic yaw control system made use of the test equipment and of the results of an earlier study. The atmospheric test equipment consisted of a horizontal axis wind turbine with vane controlled upwind two-bladed rotor of 7.6 m (25 ft) diameter having passive cyclic pitch variation. An automatically triggered electric furl actuator prevented over-speeds and over-torques by furling the rotor which means yawing the rotor out of the winds. The atmospheric test equipment was modified to accept two alternative fully automatic yaw or furl control systems. The first system was of the active type and included a hydraulic single acting constant speed governor as it is used for aircraft propeller controls. Upon reaching the rotor speed limit, the governor delivered pressurized oil to a hydraulic furl actuator which then overcame the unfurling spring force and furled the rotor. When the rotor speed fell below the set value, the governor admitted oil flow from the hydraulic actuator into the oil reservoir and the rotor was unfurled by the spring. The second automatic control system was of a purely mechanical passive type. The rotor thrust, which was laterally off-set from the yaw axis, in combination with a yawing component of the rotor torque due to uptilt of the rotor axis overcame at rated power the unfurling spring and furled the rotor. The analytically predicted and experimentally substantiated negative rotor yaw damping would cause excessive furling rates unless alleviated by a furl damper. The tests were supported by a specially developed dynamic yawing analysis. Both analysis and tests indicated that the two-bladed passive cyclic pitch wind rotor can be effectively torque or speed limited by rotor yaw control systems which are less costly and more reliable than the conventional blade feathering control systems.

• Research Organization: Washington Univ. Technology Associates, Inc., St. Louis, MO (USA)
• DOE Contract Number: AC02-77CH00178
• OSTI ID: 7097186
• Report Number(s): SERI/TR-11052-2; ON: DE83000651
• Resource Relation: Other Information: Portions of document are illegible
• Country of Publication: United States
• Language: English

Related Subjects

17 WIND ENERGY
WIND TURBINES
CONTROL SYSTEMS
TILT MECHANISMS
AERODYNAMICS
ANGULAR VELOCITY
AUTOMATION
DAMPING
DESIGN
EXPERIMENTAL DATA
HYDRAULIC EQUIPMENT
MODIFICATIONS
PERFORMANCE TESTING
SPEED REGULATORS
STABILITY
TORQUE
CONTROL EQUIPMENT
DATA
EQUIPMENT
FLUID MECHANICS
INFORMATION
MACHINERY
MECHANICS
NUMERICAL DATA
TESTING
TURBINES
TURBOMACHINERY
VELOCITY
FIELD TESTS
ROTORS
TURBINE BLADES
WIND TURBINE
170602* - Wind Energy Engineering- Turbine Design & Operation