WO2013023228A1

WO2013023228A1 - Energy-generating installation, particularly a wind turbine

Info

Publication number: WO2013023228A1
Application number: PCT/AT2012/000194
Authority: WO
Inventors: Gerald Hehenberger
Original assignee: Gerald Hehenberger
Priority date: 2011-08-18
Filing date: 2012-07-24
Publication date: 2013-02-21
Also published as: AT511862B1; AT511862A1

Abstract

The invention relates to a drive which comprises a drive shaft (2), an electric machine (8), and a differential (11 to 13) with three drives/outputs and a planetary carrier (10), a first drive (12) being connected to said drive shaft (2), an output (13) being connected to the electric machine (8), and a second output (11) being connected to a differential-drive (6). The differential (11 to 13) is located on one side of the electric machine (8) and the differential-drive (6) is located on the other side of the machine (8), said differential (11 to 13) and differential-drive (6) being interconnected by means of a shaft (16) which extends through said electric machine (8). The differential (11 to 13) is helically toothed, and a bearing (33) that absorbs axial forces, absorbing axial forces of the pinion (11), is arranged on said planetary carrier (10).

Description

Energy production plant, in particular wind turbine

The invention relates to a drive with a drive shaft, an electric machine and a differential gear with three inputs and outputs and a planet carrier, wherein a first drive with the drive shaft, an output with the electric machine and a second output with a differential drive is connected, wherein the differential gear on one side of the electric machine and the differential drive on the other side of the electric

Machine is arranged, and wherein the differential gear is connected to the differential drive by means of a shaft passing through the electric machine.

Wind power plants are becoming increasingly important

Electricity generation plants. As a result, the percentage of electricity generated by wind is continuously increasing. This, in turn, requires new standards in terms of power quality and performance

On the other hand, a trend towards even larger wind turbines.

At the same time, there is a trend towards offshore wind turbines, which require system sizes of at least 5 MW of installed capacity. Due to the high costs for infrastructure and maintenance of wind turbines in the offshore sector, both the efficiency and the manufacturing costs of the plants, with the associated use of medium-voltage synchronous generators, are of particular importance here.

WO 2004/109157 AI shows a complex, hydrostatic Mehrwege concept with several parallel differential stages and multiple switchable couplings, which between the individual ways

can be switched. With the shown technical solution the power and thus the losses of the hydrostatics can be reduced. A major disadvantage, however, is the complicated structure of the entire unit.

EP 1283359 A1 shows a 1-stage and a multi-stage

Differential gear with electric differential drive, wherein the 1-stage version has a coaxially positioned around the input shaft special three-phase machine with high rated speed, which has an extremely high on the rotor shaft mass moment of inertia due to the design. Alternatively, a multi-level Differential gearbox proposed with high-speed standard three-phase machine, which is parallel to the input shaft of the

Differential gear is aligned.

Although these technical solutions allow the direct connection of medium-voltage synchronous generators to the grid (ie without the use of frequency converters), the disadvantages of known designs, on the one hand, are high losses in the differential drive or, on the other hand, in concepts that solve this problem, complex mechanics or special - Electrical engineering and thus high costs. In general, it should be noted that cost-relevant criteria, such as optimal integration of the differential stage in the drive train of the wind turbine, were not sufficiently considered.

The object of the invention is largely to avoid the above-mentioned disadvantages and to provide a drive which, in addition to the lowest possible costs, also the best possible integration in the

Driveline of a drive guaranteed.

This object is achieved in a drive of the type mentioned according to the invention in that the differential gear is helical and that an axial forces receiving bearing is arranged on the planet carrier, which receives axial forces of the pinion.

As a result, a very compact and efficient design of the drive is possible with the addition, no significant additional mechanical loads for the electric machine of the drive,

in particular for the generator of the power plant, e.g. a wind turbine, caused.

Preferred embodiments of the invention are the subject of

Subclaims.

Hereinafter, preferred embodiments of the invention will be described in detail with reference to the attached drawings

described. It shows:

Fig. 1 shows the principle of a differential gear with an electric

Differential drive according to the prior art,

Fig. 2 shows a (possible) embodiment of a differential gear in the context of the present invention according to the prior art,

Fig. 3 shows a variant of a differential gear in

Connection with present invention with stepped planet according to

State of the art,

Fig. 4 shows an embodiment of the invention the storage of

Wave in the area of the front bearing of the generator and

Fig. 5 shows a further embodiment of the invention the bearing of the shaft in the region of the front bearing of the generator.

The power of the rotor of a wind turbine is calculated from the formula

Rotor Power = power coefficient rotor area ^* ^* ^{3 *} wind speed air density / 2, wherein the power coefficient dependent (by the tip speed ratio =

Ratio of blade tip speed to wind speed) of the rotor of the wind turbine is. The rotor of a wind turbine is designed for an optimal power coefficient based on a fast running speed to be determined in the course of the development (usually a value between 7 and 9). For this reason, when operating the wind turbine in the partial load range, a correspondingly low speed must be set in order to ensure optimum aerodynamic efficiency.

Fig. 1 shows a possible principle of a differential system for a wind turbine consisting of a differential stage 4 or 11 to 13, a matching gear stage 5 and an electric

Differential drive 6. The rotor 1 of the wind turbine, which sits on the drive shaft 2 for the main transmission 3, drives the

Main gear 3 on. The main transmission 3 is a 3-stage transmission with two planetary stages and a spur gear. Between

Main gear 3 and generator 8 is the differential stage 4, which from the main gear 3 via a planet carrier 12 of

Differential stage 4 is driven. The generator 8, preferably a third-excited medium voltage synchronous generator, is connected to the

Ring gear 13 of the differential stage 4 is connected and driven by this. The pinion 11 of the differential stage 4 is connected to the

Differential drive 6 connected. The speed of the differential drive 6 is controlled to ensure one hand at a variable speed of the rotor 1, a constant speed of the generator 8 and on the other hand, the torque in the complete driveline of

Wind turbine to fix. To the input speed for the

To increase differential drive 6 is in the case shown

multi-stage differential gear selected, which is a matching gear stage 5, in the form of a spur gear, between

Differential stage 4 and differential drive 6 provides. Of the

Differential drive is a three-phase machine, which is connected via a frequency converter 7 and a transformer 9 to the mains. Alternatively, the differential drive may also be used as e.g.

hydrostatic pumps / motor combination are performed. In this case, the second pump is preferably connected via a matching gear stage with the drive shaft of the generator 8.

The speed equation for the differential gear is:

Speed _generator = x ^* speed _rotor + y ^* speed _differential . _Antneb , where the generator speed is constant, and the factors x and y can be derived from the selected transmission ratios of the main transmission and differential gear. The torque on the rotor is determined by the upcoming wind supply and the aerodynamic efficiency of the rotor. The ratio between the torque at the rotor shaft and that at the differential drive is constant, whereby the torque in the drive train can be controlled by the differential drive. The torque equation for the differential drive is:

Torque _Ditferenzial _ _Drive = Torque _Rotor ^* y / x, where the size factor y / x is a measure of the required design torque of the differential drive.

The performance of the differential drive is essentially

proportional to the product of percentage deviation of the

Rotor speed from its basic speed times rotor power.

Accordingly, a large speed range basically requires a correspondingly large dimensioning of the differential drive. That is, the smaller the necessary speed range at the

Drive shaft is, the smaller the required differential drive and consequently the cost of its manufacture and Be operation. Turbomachines of any kind such as

Wind turbines, water turbines or pumps, systems for the extraction of energy from ocean currents, or any type of industrial plants, which operate at a limited speed range, are therefore the ideal application areas for differential systems.

Fig. 2 shows another possible embodiment of a

Differential stage in the context of the present invention. The rotor 1, which sits on the drive shaft 2 for the main gear 3, drives the main gear 3 and this via the planet carrier 12, the differential stage 11 to 13. The generator 8 is connected to the ring gear 13 and the pinion 11 with the differential drive 6. The differential gear is 1-stage, and the differential drive 6 is in coaxial arrangement both to the output shaft of the main gear 3, as well as to the drive shaft of the generator 8. The generator 8, a hollow shaft is provided, which allows the differential drive is positioned on the side facing away from the differential gear side of the generator 8. As a result, the differential stage is preferably a separate, connected to the generator 8 assembly, which then preferably via a clutch 14 and a brake 15 with the

Main gear 3 is connected. A preferably formed as a tube of glass or carbon fiber composite material with steel connecting elements at the two ends of shaft 16 connects pinion 11 and

Differential drive 6.

Main advantages of the shown coaxial, 1-stage

Embodiment are (a) the constructive simplicity and the

Compactness of the differential gear, (b) the resulting high

Efficiency of the differential gear and (c) the optimal

Integration of the differential stage in the drive train of

Wind turbine. In addition, the differential gear can be manufactured as a separate assembly and independent of the main gearbox

implemented and maintained. Of course, the differential drive 6 can also be replaced here by a hydrostatic drive, for which, however, a second, with the hydrostatic differential drive interacting pump element must be driven by preferably connected to the generator 8 gearbox output shaft.

Fig. 3 shows a possible variant of a drive train with a Differential drive and stepped planetary. As in FIG. 2, the differential drive 6 is also driven by the pinion 11 via the shaft 16. The pinion 11 is connected by means of a splined shaft 17 with the shaft 16. The shaft 16 is mounted in the generator hollow shaft 18 on the drive side by means of a bearing 19.

Alternatively, the shaft 16 may also be multiple times e.g. be stored in the generator shaft 18. Preferably, the shaft 16 essentially consists of a shaft 21 and the toothed shaft connections 17 and 22, which are preferably fixedly connected to the shaft 21. At the so-called ND end (= non-driven side) of the generator 8 of the differential drive 6 is flanged. This differential drive 6 is a

Three-phase machine with a rotor 23, a stator 24 with

integrated, circumferentially radially arranged channels 26 for the

Water jacket cooling and a housing 25. The shaft end of the rotor 23 carries the counterpart to the toothed shaft connection 22. Thus, this shaft end of the shaft 16 is mounted on the servo rotor shaft 23.

The rotor shaft 18 of the generator 8 is driven by the ring gear 13. The multipart planet carriers 12 (in the example shown three planets) are so-called stepped planets 20. These consist of two rotatably connected to each other

Gears with different numbers of teeth. The ring gear 13 is in the example shown with the smaller diameter gear of the

Stepped planet 20 in engagement, and the pinion 11 with the second gear of the stepped planet 20. Since the ring gear 13 substantially higher torques must be transmitted than via the pinion 11, the tooth width for the ring gear 13 is substantially larger than that for the pinion eleventh For reasons of noise reduction, the teeth of the differential gear is designed as helical teeth. The

individual helix angle of the teeth parts of the stepped planet 20 are chosen so that no resulting axial force acts on the storage of the stepped planetary 20. The multipart

Planet carrier 12 is mounted in the example shown twice by means of bearings 27, 28 in order to derive the forces occurring at the shaft end 29 in the transmission housing 30 can. Due to the helical gearing, an axial force and an oppositely directed axial force on the pinion 11 are produced on the ring gear 13. These axial forces have a magnitude of approximately 12 kN for the differential drive of a 3 MW wind power plant in nominal operation. To prevent the

Lateral force compensation from the pinion 11 via the shaft 16, the differential Drive 6 and the housing of the generator 8 with gearbox side

Generator bearing acts on the generator shaft 18 with the ring gear and the ring gear 13, the bearing 19 is designed as a so-called fixed bearing, which receives all, acting on the shaft 16 axial forces and introduces into the generator shaft 18. To the radial

This does not restrict freedom of movement of the pinion 11, the pinion shaft 32 is connected to the shaft 16 by means of an axially secured toothed shaft connection 17.

This technical solution provides three major benefits. These are (a) the long, fast rotating shaft 16 is free of axial forces, (b) the pinion 11 is free to radially adjust and (c) the bearing of the generator 8 can also be free of

Axial forces are designed, since the axial forces now act on the bearing 19, the generator shaft 18 and the ring gear 13.

Fig. 4 shows an embodiment of the invention

Transmission-side bearing of the shaft 16. As already in the

Embodiment shown in FIG. 3, here are the

preferably helical stepped planetary 20 mounted in the planet carrier 10, which is mounted on the one hand on the bearing 27 in the gear housing 30 and on the other hand via the bearing 28 in the ring gear 31. The fixedly connected to the pinion shaft 32 or one-piece pinion 11 is secured axially over at least in one direction

Toothed shaft connection 37 with one in the illustrated embodiment of two firmly interconnected sleeve parts existing

Guide sleeve 34 is connected and further supported by a bearing 33 both radially and axially in the planet carrier 10. By means of a

Toothed shaft connection 38 and the shaft 16 is mounted in the guide sleeve 34. The shaft 16 has to transmit only a torque in the configuration shown and can be set axially free. The transverse force compensation between pinion 11 and ring gear 13 via the bearing 27 (if this is designed as a fixed bearing) and / or 28.

Basically, it is within the scope of the invention also conceivable that the guide sleeve 34 is completely omitted or designed as part of the pinion 11 and the pinion shaft 32 and thus the pinion 11 and the

Pinion shaft 32 is mounted substantially directly in the planet carrier 10. In this case, but also in other, alternative

Ausführungsvarianten, the shaft 16 may preferably directly on or in the Pinion 11 and the pinion shaft 32, for example via a

Toothed shaft connection, be stored.

The essential advantages of these embodiments according to the invention compared to the variant according to FIG. 3 is that (a) the bearing 19 positioned in the spatially limited part of the generator shaft 18 is replaced by the bearing 33, which can be easily integrated in the planet carrier 10, (b) or position tolerances within the planetary stage are much better adhered to and the bearings 27, 28, 33, 35 and 36 all sit on the planet carrier 10 and (c) the gearbox can be completely pre-assembled and tested before it to the

Generator 8 is grown.

Fig. 5 shows a further alternative embodiment of a

Inventive storage. As a substitute for the guide sleeve 34 shown in FIG. 4 here serves a guide shaft 39, which is mounted with a thrust bearing 33 and with one or two, also mounted in the planet carrier radial bearings 40. A pinion hollow shaft 41 of the pinion 11 is mounted at least in one direction axially non-displaceably on the guide shaft 39. The pinion hollow shaft 41 is e.g. with the guide shaft 39 via an axially secured

Splined shaft connection 42 connected. As in FIG. 4, here too in FIG. 5 the guide shaft 39 is connected to the shaft 16, which in contrast to the example of FIG. 4 is designed here with a hollow shaft end via a toothed shaft connection 43.

The variants shown in FIGS. 3 to 5 are preferred examples. In addition, there are other possible variants of the construction for the initiation of the toothing forces on the one hand in the planet carrier (10) and on the other hand from the pinion 11 and the

Pinion shaft 32 or pinion hollow shaft (41) in the shaft (16), which follow the general technical rules and are not listed here.

For the sake of completeness, it should be mentioned here that the abovementioned

Advantages also for a differential stage with simple planets - i. no tiered planets - apply.

The described embodiments are only examples and are preferably used in wind turbines are in technical similar applications but also feasible. This applies in particular to water turbines or pumps and plants for the production of energy from ocean currents. The same applies to this application

Basic requirement as for wind turbines, namely variable

Flow rate. The drive shaft is in each case driven directly or indirectly by the devices driven by the flow medium, for example water.

In addition, what is said also applies to any type of system which, due to the general conditions, uses differential drives to realize variable speed on the drive shaft.

Claims

Claims :

1. drive with a drive shaft (2), an electric machine (8) and with a differential gear (11 to 13) with three inputs and outputs and a planet carrier (10), wherein a first drive (12) with the drive shaft ( 2), an output (13) to the electric machine (8) and a second output (11) with a differential drive (6) is connected, wherein the

Differential gear (11 to 13) on one side of the electric machine (8) and the differential drive (6) on the other side of the electric machine (8) is arranged, wherein the differential gear (11 to 13) with the differential drive ( 6) is connected by means of a through the electric machine (8) extending shaft (16) and wherein the differential gear (11 to 13) is helically toothed, characterized in that between the pinion (11) and the planet carrier (10) an axial forces of the pinion (11) receiving bearing (33) on the planet carrier (10) is arranged.

2. Drive according to claim 1, characterized by a guide sleeve (34) in which a pinion shaft (32) of the pinion (11) is received axially immovably at least in one direction.

3. Drive according to claim 2, characterized in that the

Pinion shaft (32) with the guide sleeve (34) via an axially secured toothed shaft connection (37) is connected.

4. Drive according to claim 3, characterized in that the

Guide sleeve (34) with the shaft (16) via a

Spline connection (38) is connected.

5. Drive according to claim 1, characterized by a guide shaft (39) which is received in a pinion hollow shaft (41) of the pinion (11) axially immovable at least in one direction.

6. Drive according to claim 5, characterized in that the pinion hollow shaft (41) with the guide shaft (39) via an axially secured toothed shaft connection (42) is connected.

7. Drive according to claim 6, characterized in that the Guide shaft (39) with the shaft (16) via a

Spline connection (43) is connected

7. Drive according to claim 1, characterized in that the pinion (11) or a pinion shaft (32) substantially directly in

Planet carrier (10) is mounted.

8. Drive according to claim 7, characterized in that the shaft (16) is mounted on or in the pinion (11) or the pinion shaft (32, 39).

9. Drive according to claim 8, characterized in that the shaft (16) directly on or in the pinion (11) and the. Pinion shaft (32) is mounted.

10. Drive according to claim 8 or 9, characterized in that the shaft (16) via a toothed shaft connection on or in the pinion (11) or the pinion shaft (32) is mounted.

11. Drive according to one of claims 1 to 10, characterized

characterized in that the electric machine (8) is a motor.

12. Energy production plant, in particular wind turbine, with a drive according to one of claims 1 to 11, characterized

characterized in that the electrical machine (8) is a generator.