DRIVE SYSTEM FOR INLAND WIND TURBINES OF HIGH HEIGHTS AND POWER

Description

[0001] The invention relates to an inland wind turbine using the high-altitude wind with a rotating tower and transmission of the rotor torque from the hub height to the drive / generator platform arranged in the lower area of ​​the tower.

[0002] Wind turbines with fixed towers designed for all wind directions are known from the technical literature. They currently have hub heights of up to 160 m. Even greater heights result in dimensions and weights that require lifting equipment, which is only available to a limited extent. The enlargement of all components of such a wind turbine leads to high costs for erection using such lifting equipment due to the increasing heights and masses / weights.

[0003] Another possibility is to mount the generator at the base of the wind turbine. This solution is known from the publication EP 2 434 153 A1. In the tower disclosed therein, the generator is located at the base. The wind power is transmitted from the top via the rotor shaft downwards to the generator by a drive train composed of several individual drives arranged one after the other in the power flow, each consisting of two pulleys and a drive belt. The base of the tower is mounted on a slewing gear opposite the foundation, allowing the entire wind turbine with the rotor to be steered into the wind.

[0004] Furthermore, US 2011 / 018269 A1 discloses a drive system for inland wind turbines, comprising a rotating tower with a rotor mounted at hub height and a drive and generator platform with a motor arranged at the base of the tower. A belt is provided for transmitting the rotor torque. The belt is arranged between a lower rotation transmission element and an upper rotation transmission element and has wire ropes between rubber layers. The wire ropes are laid parallel to each other with their respective end sections over a certain length.

[0005] Furthermore, from the publication DE 10 2008 024 829 B4 a wind energy plant is known in which the generator is provided with a flywheel to store excess energy, a coupling device and an additional motor to drive the

[0006] The generator is assigned to the drive shaft when needed. Due to their high overall weight, these components can no longer be accommodated at the top of the nacelle without additional effort. Therefore, all components downstream of the rotor axis are mounted on a base plate at the base of the wind turbine. A continuous power transmission system is provided between the rotor axis located at the top and the drive shaft located at the bottom. It can be designed as a traction drive (cable drive, belt drive, or chain drive) for the forces to be transmitted within the range of conventional hub heights and power ratings.

[0007] Other wind turbines with rotating towers are known, among others, from the publications DE 10 2012 009 145 A1, DE 20 2017 003 631 U1, and DE 20 2016 001 490 U1. Such turbines are characterized by taller towers that are rotated into the wind together with the rotor.

[0008] The object of the invention is to equip large inland wind turbines with a rotating tower with a drive system arranged between the rotor and the generator for power outputs > 5 MW in such a way that it meets the wind conditions in the lower tropospheric layers (between 100 and 400 m above the site) and meets the requirements for safety, reliability, and efficiency. In particular, the safety required for extreme torque transmission due to the greater distance between the drive and the output is to be met by electronic monitoring and suitable materials to protect against damage in the flat belt drive.Such high inland wind turbines are known in their basic design from the documents DE 20 2017 003 631 U1 and DE 10 2016 014 799 B4, without the power transmission from the rotor arranged above over a relatively large distance of almost 200 m and more by means of a drive train downwards to the generator being disclosed in detail.

[0009] This task is achieved by using a flat belt reinforced internally by parallel, high-strength steel wire ropes. These steel wire ropes are joined together at their ends. The flexible carrier material is applied to the flat belt by cover vulcanization using mobile devices.

[0010] To ensure that the drive system reliably transmits the power from the rotor shaft to the generator shaft, as with any belt drive, the tensile strength of the drive belt must be met, as well as the wrap angle, friction coefficient, and belt tension required for the various operating conditions. Due to the large distance between the upper and lower pulleys required for the belt drive, reliable belt guidance must be ensured along its entire length. Low-maintenance guide rollers are provided at specific intervals for this purpose.

[0011] The flat belt is treated over the entire length between the two pulleys to ensure the reliability of the transmission of torque between the flat belt and the pulleys, both the flat belt and the surfaces of the pulleys to guarantee the coefficient of friction µ by long-term treatment processes.

[0012] A flat belt break during operation would result in extended downtime. Therefore, an automatic monitoring system is provided that continuously monitors the integrity of the flat belt and detects even the first signs of damage to the strands of a wire rope in the flat belt, shutting down the drive system.

[0013] A high level of efficiency is aimed for the entire drive system. This is achieved through the use of flat belts and low-maintenance components. The high level of efficiency of the drive system is also achieved by ensuring that the pretension of the flat belt drive is always set as required for safe operation. For this purpose, an automatic measuring, control, and regulation device is provided, which reliably adjusts and adjusts the pretension to the respective wind conditions. This device is functionally connected to a drive and generator platform, which consists of an articulated platform on which the generator is mounted. A tensioning weight is located beneath the platform. This weight can be moved relative to the longitudinal axis of the joint using a spindle drive, thus changing the belt tension. When two or more generators are used, this pretensioning device is provided for each generator.

[0014] Further details and advantages of the subject matter of the invention emerge from the following description and the associated drawings, in which a preferred embodiment of two inland wind turbines of different construction that utilize the high-altitude wind is shown.

[0015] They show: Fig. 1 an inland wind turbine suitable for harnessing the wind in tropospheric layers, in the design with a rotating tower and spread tower cross-section, Fig. 2 an inland wind turbine suitable for harnessing the wind in tropospheric layers, in the design with a rotating tower as a vertical column and at least two counter-pressure columns, Fig. 3 the upper part of the drive system for an inland wind turbine according to the Fig. 1 or 2 and Fig. 4 the lower part of the drive system for an inland wind turbine according to the Fig. 1 or2 .

[0016] The inland wind farm according to Fig. 1 is designed for the use of high-altitude winds. It essentially consists of a rotating tower 5 with a spread tower cross-section 4, the rotor 3 with the rotor hub and rotor shaft 1, and the drive and generator platform 13. A wind turbine constructed in this way is known from the publication DE 20 2017 003 631 U1. The use of finished-rolled large-diameter pipes (up to 3 m in diameter) for the tower 5, arranged in two or more rows along the main tower axis and with increasing spread in the direction of greater downward stress, with installation on a slewing ring 6 known and proven from large excavator construction, allows for a more favorable dead mass and lower costs despite a higher energy yield compared to the previous design of the tower 5 with a bending-loaded cross-section, even with a further increased hub height (NH) in the range of 160 m (lower dashed line) to 200 m (upper dashed line).

[0017] The inland wind turbine with a rotating tower 5 and a spread-section tower 4 allows the use of the new drive system through the main tower axis to transmit the rotor torque to the drive / generator platform 13 in the rotating tower base. The upper limit of the Prandtl layer is indicated in the drawing by reference numeral 15. A lifting device 14 is mounted on tower 5 as an aid for vertical rotor blade assembly, inspection, and repair work.

[0018] One after Fig. 2 The inland wind turbine shown here is known from the publication DE 10 2016 014 799 B4 as a "TURNING TOWER." The upper image shows a side view of the turbine; the top view is shown in the lower image. The inland wind turbine consists of a rotating tower 5 with a vertical column 7 and at least two counter-supporting horizontally and vertically spread pressure columns 8. The finished-rolled large-diameter pipes in the production length for columns 7 and 8 and the finished-rolled or folded sections are joined to form tower sections. These sections are erected and joined vertically, section by section, using new technological processes—without the use of large lifting equipment—or erected as a fully equipped horizontal tower 5 mounted on the ground.

[0019] The drawing shows the horizontal spread angle 9 and the vertical spread angle 10. The nacelle 12 and the drive / generator platform 13 are located on a supporting structure at the base of the inland wind turbine. In the smaller version of the tower, the hub height (NH) is 200 m (lower dashed-dotted line), while the hub height (NH) of the larger version of the tower is 300 m (upper dashed-dotted line). This allows the higher wind speeds occurring in this area to be utilized.

[0020] The turning circle 11 for the stability of the inland wind turbine is shown in the top view according to Fig. 2 .

[0021] The drive system for transmitting the rotor torque from the height of the rotor hub1 including transmission and / or drive train branching for speed-adjusted conversion of the torque to the generator 16 in the rotating towers 5 of the two inland wind turbines is shown in the drawings according to the Fig. 3 (upper area) and Fig. 4 (lower section). The power transmission element between the two pulleys 2 and 17 is a flat belt 18. It is internally reinforced by several parallel high-strength steel wire ropes, which are arranged between the running layer and the cover layer in the tension layer. This steel wire rope-reinforced, loop-forming flat belt 18 integrates a desired transmission ratio through the different diameters of the upper and lower pulleys 2 and 17.

[0022] The drawings after the Fig. 3 and Fig. 4 show the basic structure of a drive train branched drive in the rotating tower 5 with a branching to two generators 16. Two flat belts 18 are guided from the upper large pulley 2 via guide rollers that are always mounted parallel through the tower 5 downwards to two pulleys 17. Each of the two associated generators 16 is located on the drive / generator platform 13 and generates the majority of the belt pretension through its own mass. In addition, the rocker 21 with the pretension weight 20 has the ability to regulate the pretension depending on the wind speed. Fig. 4 A drive train branching with two generators 16 is shown. However, such a design is not mandatory. Power transmission from top to bottom can also be achieved via a flat belt 18 to a generator 16. The main axis of the rotating tower—from the rotation on the ground to the drive in the rotating tower base and the drive train branching, steel wire rope-supported, loop-forming flat belt drive, including the transmission ratio between rotor shaft 1 and the shaft of the generator 16—ensures reliable continuous operation at any hub height.

[0023] The flat belt 18 is guided downwards inside the vertical column and is thus protected from external influences (rain or dust, etc.) and damage to the drive system. List of reference symbols

[0024] 1 Rotor hub with rotor shaft 2 pulley 3 rotor4 splayed tower cross-section 5 rotating tower 6 Slewing ring 7 vertical column 8 pressure column 9 horizontal spread angle 10 vertical spread angle 11 Turning circle 12 Engine room / operation 13 Drive / generator platform 14 Own lifting equipment 15 upper boundary of the Prandtl layer 16 generator 17 pulley 18 Flat belts 20 Preload weight 21 swingarm NH Hub height

Claims

1. A drive system for an onshore wind power installation, composed of a rotatable tower (5) having a rotor (3) mounted at a hub height (NH) and a drive and generator platform (13) disposed at the foot of the tower (5), wherein a flat belt (18) enabling a reliable operation with good efficiency and a long service life is provided for transmitting the rotor torque, wherein - as a transmission element in one or multiple parts, a flat belt (18) which is connected by loops, and by way of a large belt pulley (2) at the hub height (NH), and by way of guide rollers on the path to the small belt pulley (17) on the drive / generator platform (13), transmits and feeds the rotor torque singularly or while bifurcating through the drivetrain; - the flat belt (18), by way of incorporated steel wire ropes is available as a high-tensile flat belt (18) also in double the length of the spacing of the upper belt pulley (2) from the lower belt pulley (17); - the high-tensile flat belt (18) by way of wire rope combinations and connections, while interacting with the material of the vulcanization, is suitable for forming a loop at any arbitrary location in the flat belt (18) as well as at every location in the belt arrangement in the rotatable tower (5); - in addition to the permanent pre-tensioning of the flat belt (18) from the floating dead weight of the drive / generator platform (13), an optimal position of the pre-tensioning weights (20) by means of CMS is provided for the fine adjustment to the currently prevailing wind conditions; and - automatic monitoring for permanently checking the integrity of the flat belts (18) is provided, said automatic monitoring performing the immediate controlled shut-down of the drive system in the event of damage.