Wind turbine blades
AssigneeSir Henry Lawson-Tancred, Sons & Co. Ltd.
InventorHenry Lawson-Tancred
Life of this patent
Estimating the term…
Abstract
Wind turbine blades for use e.g. in generating electricity are described in which the blades have fixed lift spoilers in the form of deep spars projecting on the normally high pressure side of the blades where they are relatively ineffective, but which, in down-wind operation of the turbine, are on the low pressure side which generates (but for the spars) substantially all the lift and are therefore very effective. Active spoilers are also disclosed on the low pressure side of the blade rapidly deployable to control an overspeed condition. The whole is controlled by a computer to maintain desirably constant tip speed ratio, the variable rotor speed being converted hydraulically or electrically to constant frequency current, or to maintain a constant turbine speed to generate constant frequency current with overspeed protection.
Claims27
A wind turbine blade having an envelope which defines an airfoil profile having, in normal operation, a first, high pressure side, a second, low pressure side, and further having a leading edge and a trailing edge, which edges define an airfoil chord line extending between them, and comprising
- a blade structure incorporating a fixed blade spar which extends outwardly on said first side from within the blade envelope and perpendicularly across said chord line to a position with respect to the blade cross-section which is external of the blade surface and spaced from said airfoil profile,
- said blade spar comprising a strengthening member mounted along the length of the blade and disposed to disrupt air flow over the blade only in the event that the instantaneous wind direction is reversed so that said first side becomes the low pressure side.
A wind turbine comprising at least one wind turbine blade having an envelope which defines an airfoil profile having, in normal operation, a first, high pressure side, a second, low pressure side, and further having a leading edge and a trailing edge, which edges define an airfoil chord line extending between them, and comprising
- a blade structure incorporating a fixed blade spar which extends outwardly on said first side from within the blade envelope and perpendicularly across said chord line to a position with respect to the blade cross-section which is external of the blade surface and spaced from said airfoil profile,
- said blade spar comprising a strengthening member mounted along the length of the blade and disposed to disrupt air flow over the blade only in the event that the instantaneous wind direction is reversed so that said first side becomes the low pressure side.
Dependencies are inferred from the claim text.