1. Technical Field
The subject matter described here generally relates to wind turbines, and, more particularly, to power generation using a wind turbine brake.
2. Related Art
A wind turbine is a machine for converting the kinetic energy in wind into mechanical energy. If the mechanical energy is used directly by the machinery, such as to pump water or to grind wheat, then the wind turbine may be referred to as a windmill. Similarly, if the mechanical energy is converted to electricity, then the machine may also be referred to as a wind generator or wind power plant.
Wind turbines are typically categorized according to the vertical or horizontal axis about which the blades rotate. One so-called horizontal-axis wind generator is schematically illustrated in
The wind turbine 2 typically has numerous devices that are powered by batteries in order to operate during a power outage. Recharging those batteries is generally not possible if the turbine 2 is spinning freely but not generating power, such as when idling or coming up to speed during a cold start. Wind turbines 2 also generally include redundant braking systems for locking the drive train 8 and/or blades 10. At least one of those braking systems typically includes a brake disk capable of stopping the turbine 2 against full wind torque. These wind turbine braking systems often further include a hydraulic accumulator, spring, or other energy storage device that enables operation of the brake in the event of a power failure.
These and other aspects associated with such conventional approaches are addressed here in by providing, in various embodiments, a wind turbine including a tower for supporting a nacelle; a gearbox connected to an electrical generator arranged in the nacelle; a plurality of blades for rotating the gearbox and driving the generator; a brake disk for stopping rotation of at least one of the gearbox and the generator; and an auxiliary power source, driven by the brake disk, for generating power.
Various aspects of this technology will now be described with reference to the following figures (“FIGS.”) which are not necessarily drawn to scale, but use the same reference numerals to designate corresponding parts throughout each of the several views.
The gearbox 14 has a brake disk 102 that is activated by a brake (not shown) for stopping rotation of the gearbox 14. The brake disk 102 illustrated here is arranged on the high-speed side of the gearbox 14, between the gearbox 14 and the (main) generator 16. The brake disk 102 is typically attached to the shaft of the gearbox 14, but may alternatively be attached on the generator side of the gearbox 14. Other brake disk arrangements are also possible.
One or more auxiliary power sources may be mounted on or near the main gearbox 14 and driven by the brake disk 102 in order to generate power. For example, the auxiliary power source may include an alternator or second (auxiliary) generator 104 as shown in
In
As illustrated in the embodiment shown in
A power storage device may be connected to any or all of the auxiliary power sources for receiving and storing power from those power sources. For example, as illustrated in
The technology disclosed above offers various advantages over conventional approaches. For example, the auxiliary power sources draw minimal torque from the brake disk 102 wheel, the majority of which is then fed into the generator 16 that produces power for the grid. These auxiliary power sources can provide power even when the generator 16 is off-line. Where the output of the second generator 104 is used to recharge batteries, this stored energy can later be used to provide power for various purposes including pitch control actuators 24 or 116 and gearbox oil heating 118. Such heating is particularly important in getting the wind turbine 2 for power production during extreme cold weather and could therefore help to quickly bring the wind turbine 2 to power production and thus increased the overall power production of the turbine 2. Where the output of the compressor 106 is used to compress air, this stored energy can later be used to power hand tools that are used for maintain the wind turbine 2. Since compressed air-powered hand tools 124 are relatively light weight, this aspect of the disclosure avoids the need to manually carry heavy tools up the tower 4 into a nacelle 6.
It should be emphasized that the embodiments described above, and particularly any “preferred” embodiments, are merely examples of various implementations that have been set forth here to provide a clear understanding of various aspects of this technology. One of ordinary skill will be able to alter many of these embodiments without substantially departing from scope of protection defined solely by the proper construction of the following claims.