Topic
Blade pitch
About: Blade pitch is a research topic. Over the lifetime, 5321 publications have been published within this topic receiving 63134 citations.
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15 Jul 2001
TL;DR: In this article, a configuration of variable speed system which includes a pitch controllable horizontal axis wind turbine, a cage induction generator, a PWM (pulse width modulation) converter and a pWM inverter, the last one being connected to utility grid.
Abstract: Variable speed operation of wind turbines has the potential to in crease energy capture and reduce fatigue damage, compared with fixed speed operation. Cage induction generators with their brush-less and rigid structure are at present widely used for fixed speed wind systems. To make the cage induction generators widely used also at variable speed systems, proper control strategies should be developed as well as the development or low cost and reliable power electronic devices. At high wind speeds, as is conventional fixed speed system, It is very important to limit the variable speed system to its ratings without mechanical and electrical stresses induced by wind gusts and/or control process. Ibis paper introduces a configuration of variable speed system which includes a pitch controllable horizontal axis wind turbine, a cage Induction generator, a PWM (pulse width modulation) converter and a PWM inverter, the last one being connected to utility grid. Also, the paper proposes and investigates a class of control strategies for limiting the system to its ratings, from the view point of avoiding axial torque and/or generator power fluctuations induced by wind gusts and control errors. The class adopts parallel operation of pitch angle control and electrical power control. The pitch control alms at limiting turbine rotational speed, while generator power control alms at eliminating torque and/or power fluctuations. Simulation results In time domain are presented to verify the effectiveness of the class of controls.
70 citations
01 Dec 2005
TL;DR: In this paper, a finite-element code that provides dynamically coupled modes for a beam can be used to provide accurate modeling of major flexible components for modal-based aeroelastic codes such as FAST (Fatigue, Aerodynamics, Structures, and Turbulence).
Abstract: This guide explains data preparation and execution with BModes, a finite-element code that provides dynamically coupled modes for a beam. The beam can be a rotating or non-rotating rotor blade or a tower, and it can have arbitrary distribution of structural properties and geometry along its length. A coupled mode implies presence of coupled flexural, axial, and torsion motions in a natural mode of vibration. Knowledge of flap-lag-torsion-axial coupled modes is crucial to several applications. Examples are: accurate modeling of major flexible components for modal-based aeroelastic codes such as FAST (Fatigue, Aerodynamics, Structures, and Turbulence), validation of flexible component models using experimental data, modal-based fatigue analysis, and interpretation of aeroelastic-stability behavior of turbines. Our plan is to eventually integrate BModes with FAST to provide tower and blade modes as rotor speed and blade pitch control settings change during a simulation. This guide provides step-by-step instructions on how to prepare input files (specify blade geometry, section properties, and finite-element discretization), how to execute the code, and how to interpret the outputs.
70 citations
Patent•
22 Sep 1992TL;DR: In this article, variable pitch blades are changed by an actuator having first and second ac machines, and the first ac machine is excited with ac power to apply motoring torque to a control shaft of the actuator, thereby causing blade pitch to change in one direction.
Abstract: Blade pitch of variable pitch blades is changed by an actuator having first and second ac machines. The first ac machine is excited with ac power to apply a motoring torque to a control shaft of the actuator, thereby causing blade pitch to change in one direction. The second ac machine is excited with appropriate power to apply a braking torque to the control shaft, thereby causing blade pitch to change in an opposite direction. When the second ac machine is an induction machine, dc excitation will brake the control shaft. When the second ac machine is a synchronous machine, an ac excitation causing a retarding magnetic field will brake the control shaft.
69 citations
Patent•
28 Dec 2007TL;DR: In this paper, a wind turbine having at least one rotor blade attached to a rotor hub is provided, where the sensor is adapted to detect an aerodynamic condition of the rotor blade.
Abstract: A wind turbine having at least one rotor blade attached to a rotor hub is provided, wherein the wind turbine further includes at least one sensor disposed at or near the rotor blade, the sensor being adapted to detect an aerodynamic condition of the rotor blade.
69 citations
Patent•
30 Aug 2007TL;DR: In this article, a wind turbine system with a pitch control mechanism, an emergency power supply mechanism, and a variable pitch angle was described. But the pitch control was not used to control the pitch angle.
Abstract: A wind turbine system is provided with a wind turbine rotor, a pitch control mechanism, and an emergency power supply mechanism. The wind turbine rotor includes a blade having a variable pitch angle. The pitch control mechanism drives the blade to control the pitch angle. The emergency power supply mechanism generates electric power from rotation of the wind turbine rotor and feeds the electric power to the pitch control mechanism, in response to occurrence of an accidental drop of a system voltage of a power grid.
69 citations