Wind turbine having flow-aligned blades

摘要

A wind turbine blade is configured such that the lift force from the blade airfoil is always normal, or nearly normal, to the shaft torque. This condition maximizes energy conversion. This objective may be achieved by a) having the airfoil chord always aligned to the actual wind direction (subject only to small angle of attack variations), and b) slowing the turbine rotation rate so that no blade twist is needed. As a result, blade tip speed due to shaft rotation is less than the wind speed, and preferably much less. This low tip speed eliminates any hazard to birds. The lift force from the blade airfoil directly drives the torque on the shaft, so the control problem simplifies to adjusting the blade angle of attack to keep the lift constant across varying wind speeds.

主权项

1. Apparatus for generating power from a moving fluid, comprising:
a rotor structure comprising a plurality of rotor blades, the rotor blades being configured to enable an alignment condition such that for each of the plurality of rotor blades, and along a majority of a length of each of the plurality of rotor blades, a rotor blade chord is aligned predominantly with a direction of fluid flow; a coupling structure that couples the rotor structure to a shaft forming a horizontal axis of rotation; and a controller coupled to the rotor structure for controlling at least one of rotation speed and torque of the rotor structure, wherein the controller is configured to, during a power generation condition, control rotation speed such that a tip speed ratio of each of said plurality of rotor blades is less than one.