Blade pitch

About: Blade pitch is a research topic. Over the lifetime, 5321 publications have been published within this topic receiving 63134 citations.

Pitch Angle Control for Variable Speed Wind Turbines

Abstract: . Pitch control is a practical technique for power regulation above the rated wind speed it is considered as the most efficient and popular power control method. As conventional pitch control usually use PI controller, the mathematical model of the system should be known well. This paper deals with the operation and the control of the direct driven permanent magnet synchronous generator (PMSG). Different conventional strategies of pitch angle control are described and validated through simulation results under Matlab\Simulink.

Wind turbine generator rotor blade

Abstract: The rotor blade has a fully enclosed surface (6) at the tip (2) of the rotor blade, through which the air can pass without any additional air resistance. The closed surface is pref. provided by a ring, formed by a tube section (5) attached to the tip of the rotor blade, with or without a gap(s) in its peripheral surface.Pref. the tube section is made of a conductive material, e.g. high quality steel, for additionally providing a lightning protection function, the dia., length and relative spacing of the ring surface from the blade rear edge selected to provide the optimum compromise between the noise reduction and the increase in air resistance.

Measurement of Static and Dynamic Performance Characteristics of Electric Propulsion Systems

Abstract: Today’s unmanned aerial vehicles are being utilized by numerous groups around the world for various missions Most of the smaller vehicles that have been developed use commercially-off-the-shelf parts, and little information about the performance characteristics of the propulsion systems is available in the archival literature In light of this, the aim of the present research was to determine the performance of various small-scale propellers in the 40 to 60 inch diameter range driven by an electric motor An experimental test stand was designed and constructed in which the propeller/electric motor was mounted in a wind tunnel for both static and dynamic testing Both static and dynamic results from the present experiment were compared to those from previous studies For static testing, the coefficient of thrust, the coefficient of propeller power, and the overall efficiency, defined as the ratio of the propeller output power to the electrical input power, were plotted versus the propeller rotational speed For dynamic testing, the rotational speed of the propeller was held constant at regular intervals while the freestream airspeed was increased from zero to the windmill state The coefficient of thrust, the coefficient of power, the propeller efficiency and the overall efficiency were plotted versus the advance ratio for various rotational speeds The thrust and torque were found to increase with rotational speed, propeller pitch and diameter, and decrease with airspeed Using the present data and data from the archival and non-archival sources, it was found that the coefficient of thrust increases with propeller diameter for square propellers where D = P The coefficient of thrust for a family of propellers (same manufacturer and application) was found to have a good correlation from static conditions to the windmill state While the propeller efficiency was well correlated for this family of propellers, the goodness of fit parameter was improved by modifying the propeller efficiency with D/P

Blade row arrangement for turbo-engines and method of making same

Abstract: A blade row arrangement for turbo-engines has an axial construction with two guide blade rows fixedly positioned relative to one another and having a different number of blades while the blade pitch is constant in each case, and having a moving blade row arranged between the two guide blade rows. The blades of the first guide blade row, in a first partial area of the row, successively have an identical axial offset; the axial offset being selected as a function of the blade number ratio of the two guide blade rows such that it increases the effective flow-off cross-section when the first guide blade row has more guide blades than the second guide blade row and reduces the effective flow-off cross-section when the first guide blade row has less guide blades than the second guide blade row. The blades of the first guide blade row, in a second partial area of the row, successively have an axial offset which is opposite in relation to the blades in the first partial area. The axial offset for the respective sections may be different in size as well as axial direction.

The SHARCS project: Smart hybrid active rotor control system for noise and vibration attenuation of helicopter rotor blades

Abstract: The SHARCS project aims to develop an actively controlled helicopter rotor for the simultaneous suppression of vibration and noise. The proposed rotor will incorporate three subsystems of active control: an active impedance control device, which will replace the classical pitch link rods to reduce vibrations transmitted to the rotor hub, an actively controlled trailing edge flap to reduce vibrations due to dynamic stall and BVI as well as to reduce noise, and an actively controlled anhedral tip for the reduction of noise. The project is an international effort of seven partner institutions from Canada, Italy and Greece, which goal is to design, build and wind tunnel test a scaled rotor incorporating all three subsystems. The present paper describes the project structure and the progress made in the individual areas of research and design in the first year of the project.