EP2087234A2

EP2087234A2 - Energy generation plant, driven by wind or water currents

Info

Publication number: EP2087234A2
Application number: EP07846774A
Authority: EP
Inventors: Norman Perner; Benjamin Holstein
Original assignee: Voith Patent GmbH
Current assignee: Voith Patent GmbH
Priority date: 2007-01-18
Filing date: 2007-11-23
Publication date: 2009-08-12
Also published as: KR20090100432A; US8436483B2; KR101460123B1; DE102007003618A1; WO2008086839A2; CA2676013C; US20100052325A1; WO2008086839A3; TWI401360B; TW200835852A; CA2676013A1

Abstract

The invention relates to an energy generation plant for obtaining electric energy from a wind or water current, comprising: a turbine; an electric generator with a coaxial arrangement of the rotor and stator, the rotor being an external rotor and forming part of an annular supporting structure for the turbine and the stator being held in a stator housing that is sealed off from the surrounding medium. A wall region of the sealed stator housing runs in the vicinity of the gap between the rotor and the stator in such a way that the rotor lies radially outside the sealed stator housing and the magnetic interaction between the rotor and the stator takes place through said wall region; a bearing for the annular supporting structure which comprises the rotor, said bearing bordering the gap between the rotor and the stator and being supported on the outer periphery of the sealed stator housing.

Description

Power generation plant driven by a wind or water flow

The invention relates to a powered by a wind or water flow power generation plant, in particular a power plant for the production of electrical energy from a flowing water or ocean current or by wind power in the offshore area.

Diving energy generation systems designed independently of dam structures, which are driven by the kinetic energy of a water flow, in particular a sea current, represent a great potential for the utilization of regenerative energy sources. Due to the high density of the flow medium, a low flow velocity of about 2 to 3 is already possible Take advantage of 2.5 m / s for economic energy production. Such flow conditions can be present either as a tidal current or other ocean currents are exploited, which can reach economically exploitable speeds, especially at straits. Such flows can drive flow power plants, which have a similar design as wind turbines, that is, as water turbines, impellers are used with rotor blades. However, other water turbine concepts, such as vertical turbines and bulb turbines, conceivable. In addition to the scope of energy recovery from ocean currents such freestanding, diving power generation plants can also be found in streams in which due to environmental protection or transport regulations no barrage with built-in water turbines can be built.

A fundamental difficulty in the operation of submerged flow power plants is that maintenance is expensive, especially in the offshore sector. Usually, for this purpose, the water turbine and the associated electric generator must be raised above the water level. Due to the dependence on the weather conditions and the Swell in this case floating crane systems are disadvantageous, so that the flow power plants are often formed as a buoyant units having an anchorage to the seabed or the bottom of the watercourse. Such buoyant units can be designed so that for servicing a flooding to the water surface is possible. According to an alternative embodiment, the flow power plant is held in flow on a support and support structure, in particular a columnar arrangement standing on the seabed. If this support and support structure continues to the water level, it is possible to move the power generation system for the maintenance case vertically to this structure. Typically, such support and support structures protrude beyond the water level and are associated with a lift mechanism. In addition to the constructive complex design is disadvantageous in this case that over the water level and just below structures arranged for shipping can pose dangerous obstacles.

Similar problems arise for offshore wind turbines, which are subject to constant corrosion by the surrounding salt mist atmosphere. Maintenance work is already difficult to do because of the location. In addition, future offshore wind turbines will be powerful and large in size, which places special demands on lifting systems for maintenance.

Based on the maintenance problem of the generic power generation systems, the object of the invention is to design a submerged flow power plant or a wind turbine so that they are low maintenance, and as completely as possible to dispense with a service. In addition to the corrosion resistance and robustness, the power generation plant should be characterized by a structurally simple design. The object is solved by the features of the independent claim. Advantageous embodiments emerge from the subclaims.

The power generation plant according to the invention has a reduced number of individual components to increase the reliability. In particular, is reduced by a direct drive of the generator on the one hand, the number of components in the drive train, on the other hand is achieved by dispensing with gear components that the typically slow movement of the water or wind turbine is transmitted directly to the generator rotor and so the wear associated with the mileage decreases , Furthermore, this opens the possibility to dispense with oil-based lubrication circuits in the nacelle of a water or wind turbine.

If the generator is designed, for example, as a high-pole synchronous generator and in particular as a ring generator, then, in spite of the slow rotational speed, an induced voltage can be generated whose frequency corresponds to a high-speed generator. Alternative designs for such low-speed electrical generators may consist in that the plurality of poles is not formed on a single circumference of an annular rotor-stator pair, but that these poles are distributed to a plurality of axially spaced generator units, which, for example, in DE 103 54 953 A1 is described.

In addition to the direct drive for the generator, a can is provided for the power generation plant according to the invention, that is, in the region of the gap between the rotor and the stator of the electric generator runs a partition through which penetrates the magnetic field for interaction between rotor and stator, but which stationary components of the electric generator separated from the outside, without the need for maintenance-prone shaft seals must be used. The separation leads to a liquid-tight sealed interior area in the case of a driven by a flow of water power plant and accordingly a gas-tight enclosed interior for a wind turbine. Accordingly, the stator of the power generation plant according to the invention is stored within a hermetically sealed stator housing, for which only static seals are used. In comparison, when using moving seals, such as a shaft seal, a certain leakage can not be ruled out safely, so that can not be dispensed with Lenzpump- and filter and / or air treatment systems for the interior. For a power generating plant with stator encapsulation according to the invention, however, this is not necessary. In the protected housing, the further control of the power generation plant as well as the components required for the power electronics and the frequency converters for connecting the electric generator to a grid with a constant mains frequency can be accommodated in the protected environment.

Particularly preferred for realizing the direct drive is a structural unit consisting of a water or wind turbine, which is referred to below as a turbine, and the rotor of the electric generator. If the electric generator is configured as a ring generator, it is particularly preferable to use an annular external rotor of the generator, which at the same time serves as a supporting structure for a propeller-shaped turbine. Accordingly, the pointing to the axis of rotation ends of the propeller blades are connected to an annular support structure which carries in the region of its inner circumference according to an advantageous embodiment, a sequence of permanent magnets which form the magnetic components of a permanent-magnet rotor of the electric generator. Consequently, the turbine and the rotor of the generator receiving annular support structure are structurally connected and arranged coaxially and concentrically. Radial inside and in turn concentric with this assembly is the stator housing with the stator windings received and encapsulated therein.

The annular support structure will preferably have a radius, which on the one hand to the mechanical requirements for supporting the load application is adapted by the turbine and on the other to the space requirement for housing the generator rotor. The propeller-shaped turbine can then be designed as an external rotor large-building, which leads due to the large turbine diameter to powerful power generation plants.

As a further inventive measure, the bearing of the annular support structure is carried out so that the recorded via the turbine static and dynamic moments lead to the lowest possible bearing forces. According to the invention, the bearing is arranged directly in the region of the gap between rotor and stator of the electric generator. Particularly preferably, the bearing is supported against the stator encapsulating the stator and arranged on the largest possible outer circumference. In addition, at least two bearings are preferred with a sufficient axial distance, so that high tilting moments can be intercepted by the opposite bearing areas and at the same time the deformation of the bearing components remains in a suitable area for a continuous load area.

Preferably, bearings are used with rolling elements, which are accommodated in bearing shells, which are formed in the annular support structure and on the opposite side on the outside of the stator housing. Due to the arrangement of the turbine radially outward, the size of the annular support structure and thus the diameter of the bearing shells can be chosen so that their precise production can be carried out. As an alternative to bearings with rolling elements sliding bearings can be used, which in turn have run-off surfaces which are formed on the annular support structure and the stator housing.

Due to the inventive storage in the region of the stator-rotor gap of the electric generator, it is also possible to keep the gap distance as constant as possible even under heavy loads, thereby realizing small gap distances and thus a high efficiency of the generator can be. In addition, it is possible to use water-lubricated bearings as bearing components due to the minimized bearing forces, which are used outside of the stator housing and thus in the liquid-flow area of the power generation plant, without a discharge of oil-based lubricants from storage to the ambient water.

According to an advantageous embodiment of the power generation plant according to the invention, the bearing components are protected from abrasive components in the flow water, in ocean currents these are in particular sediment entrained by the flow. In the case of wind turbines, problems are caused by particles, such as grains of sand, that are transported by the air flow. In the simplest case, the protection is achieved by the assignment of sealing components, such as a labyrinth seal, to a bearing, so that this is separated from the outside by a first, filtering element acting. Additionally or alternatively, according to a further embodiment between the stator housing and the annular support structure, a device is provided which causes an outward flow of filtered ambient water for a driven by a flow of water power plant. For a wind turbine according to the invention, a flushing with filtered air or another purge gas will accordingly take place. For better understanding, an embodiment of a seal or bearing purging is shown below for a power plant driven by a water flow. For a wind turbine, a specialist can make appropriate adjustments.

Accordingly, the water-lubricated bearings are particularly advantageously flowed through with filtered water in the outward direction, which is particularly easy to achieve with a double row bearing arrangement and a filter water supply provided between the axially spaced bearing components. If, in addition to the protection, a sealing component, such as a labyrinth seal, provided on the outer region of the bearing, so may according to an alternative Design the outward flow with filtered water either done only by the seal component, so that alluvium is prevented from abrasive substances to the camp. According to a further design, the filter water flow takes place both through the bearing, as well as subsequently by the sealing element assigned to the outer region, so that both a bearing purging and a sealing purging can be realized. Also, a bearing flush without a simultaneous seal flushing or alternatively the waiver of the failure-prone seal and the use of an open bearing with a bearing flushing through filter water is possible.

According to a further embodiment of the invention, the turbine is designed with adjustable blades. In the case of a propeller-shaped geometry for the turbine, a regulation of the power consumption and the rotational speed can take place due to the angular blade adjustment. To realize such a setting of the turbine adapted to the respective flow conditions or the operating situation, it is necessary for the inventive encapsulation of the stator in a liquid-tight stator housing, for the assembly of annular support structure, rotor and turbine a separate energy source for operating the adjusting elements for the adaptation of Turbine, in particular a device for the blade angle adjustment to provide. For this purpose, a circumferential, the rotating assembly associated hydraulic pump can be used, which meshes, for example, a toothing on the stator housing and which serves for the operation of hydraulic adjusting devices for adjusting the turbine. Alternatively, the energy transfer and / or a signal transmission, for example of control and monitoring signals and signals for the sensor, from the stator to the rotating unit contactless, inductive, whereby an electric actuator can be realized in particular for angular blade adjustment.

According to an alternative design is on an active adjustment of the turbine, that is, in the case of a propeller-shaped turbine on the Blade angle adjustment, omitted. This in turn increases the reliability due to the resulting reduction in the number of components. However, the disadvantage is that precautions must be taken to reduce the energy input through the turbine as quickly as possible in the case of a load shedding. For the safe deceleration of the turbine according to a further embodiment of the invention, such a construction of the turbine is selected, which rotates only in the case of an applied generator torque, that is, for normal operation, the turbine blades in the attack position and in the event that the generator torque abruptly breaks off, the turbine is automatically returned by the flow forces on the turbine blades in a non-attack position, whereby the uncontrolled run-up of the turbine can be minimized without elaborate braking devices.

This concept is implemented by virtue of the fact that the turbine comprises at least two subcomponents which are rotated relative to one another by the action of the generator torque and in this case rotate the turbine blades into the flow. If a load shedding occurs, this Relatiwerdrehung is due to the omission of the generator torque returned by the Stömungskräfte, so that the generator torque forms the actual control and regulating body, the force for the active position of the turbine results from the generator torque - this represents the normal operation case means triggered, the turning out of the turbine blades from the flow in turn by eliminating the generator torque.

The invention will be illustrated below with reference to preferred embodiments in conjunction with the figures. These show in detail the following:

Figure 1 shows an inventive power generation plant in axial section. FIG. 2 shows a power generation system according to the invention according to FIG. 1 in an embodiment with a pump-filter device for bearing and / or seal flushing.

Figure 3 shows a pump-filter device for an inventive

Power generation plant that operates on the centrifugal principle and is self-cleaning.

FIG. 4 shows two variants for a blade angle adjustment with separate or encapsulated energy generation for a power generation plant according to the invention.

Figures 5a and 5b show a simplified schematic over the

Generator torque controlled active and passive position of the turbine.

FIG. 1 shows the basic concept according to the invention of a low-maintenance power generation plant in axial section. According to the arrow, an influx flows through the sea or river water flow. In the present embodiment, the turbine 1 is formed like a propeller and comprises for the embodiment shown at least two propeller blades 54. According to the invention, the turbine 1 directly, that is without the interposition of gear stages, connected to the rotor 3 of an electric generator 2, wherein particularly preferably a compact unit is used in coaxial, concentric arrangement according to the representation of Figure 1. Here, the propeller blades 54 of the turbine 1 are articulated radially inwardly to an annular support structure 60, wherein in the annular support structure 60, the magnetic components of the rotor 3 are integrated. Preference is given here to the arrangement of a plurality of permanent magnets on the inner circumference of the annular support structure 60, wherein, for example, high-performance magnets of a neodymium-boron-iron alloy are used. The stator 4 with electrical steel stacks and induction windings of the electric generator 2 is located within a liquid-sealed, dry stator housing 5, so that a wall region 5.1 in the sense of a gap tube in the gap 63 between the rotor 3 and the stator 4 of the electric generator 2 separates the encapsulated region within the stator housing from the outer rotor. The stator 4 is arranged coaxially with respect to the rotor 4 with respect to the axis 60 and concentrically disposed on the inside. In addition to the sealed stator housing 5, the gondola 70 of the power plant may include other areas, such as a housing cover 62, which are not completely sealed from the surrounding medium. Furthermore, the connection of the nacelle 70 and a supporting and supporting structure is not shown in detail in the figures.

The wall area 5.1 in the gap 63 between rotor 3 and stator 4 must be made of a material which weakens the magnetic field of the rotor as little as possible. Particularly austenitic steel for forming the liquid-tight stator housing 5 is preferred for the power generation plant according to the invention. This is essentially non-magnetic at normal temperatures. In addition, a corrosion-resistant material should be chosen, especially when operating the power plant in salt water or a salt mist atmosphere. Alternatively, metallic alloys based on aluminum and zinc may be used, which may have polymer-based anti-corrosion coatings.

As electrical generator 2, a high-pole synchronous generator in the form of a ring generator is preferably used, which is connected via frequency converter to a line network.

Furthermore, a bearing 6 in the region of the gap 63 between the rotor 3 and the stator 4 of the electric generator 2 is provided for the power generation plant according to the invention. The bearing 6 of the annular support structure 60, in which the rotor 3 is integrated, is preferably formed in two rows and consists of at least two axially spaced bearing components 6.1 and 6.2, each axially adjacent to the gap 63rd connect. These serve to set a certain gap distance and to support the turbine forces. By thus arranged storage, it is possible to initiate the recorded by the turbine 1 moments in the region of the outer circumference of the stator housing 5. Due to the large-scale bearing components 6.1, 6.2 and their large axial and radial Aussteckung it is possible to keep low in the bearing components 6.1 and 6.2, in particular the bearing shells pressing forces and the resulting deformations. By virtue of this measure, bearing components 6.1, 6.2, which are designed as water-lubricated bearings, can also be used for the high dynamic and static moments acting on a turbine 1. This is particularly important in view of the fact that a circulating external rotor is used and the area of the gap 63 is also flooded by the running water.

The design of the bearing 6 may be selected within the skill of the art and include single row cylindrical roller bearings with sufficient axial extent or double row, axially spaced ball roller bearings, preferably each with water lubricated ceramic insert, or plain bearing bushes. According to a particularly preferred embodiment, the bearings 6 are designed so that they give the moving assembly, comprising the annular support structure 60 with integrated rotor 3 and the turbine 1, additional support in the axial direction. Furthermore, the bearing shells can be formed in the stator housing 5 and in the annular support structure 60. Their diameter is sufficiently large that the bearing force forces remain small. On the other hand, due to the arrangement of the annular support structure 60 radially inward of the turbine 1, these diameters are small compared to a jacketed turbine, so that bearing shells in these components can still be produced precisely.

In summary, the power generating device shown in Figure 1 is characterized by the fact that wear-prone transmission components are superfluous by the direct generator drive. In addition, a sealed inner region of a stator housing 5 is formed by the canned arrangement, which has only static seals and in which all moisture or corrosion sensitive electrical control and power components are housed.

In addition, the bearing 6 according to the invention allows the rotating components by a bearing on the stator 5 and in particular the outer periphery bearing shell even at high torque loads, the gap distance between the rotor 3 and the stator 4 of the electric generator 2 to keep constant and for such conditions to minimize the bearing forces so far that water-lubricated bearings can be used without any special design effort.

Further, it is conceivable, instead of the coaxial arrangement of generator rotor 3 and stator 4 to provide a disc-shaped arrangement, according to the invention again a liquid-tight stator is present and the rotatable assembly of generator rotor 3 and turbine 1 is preferably supported via a bearing on the outer circumference of the stator. Alternatively, the bearing support on the stator housing can also be made on the front side over a large radius. This variant is not shown in detail in the figures.

Due to the power generation plant according to the invention are interference-sensitive shaft seals, which are usually not completely sealed, replaced by a liquid- or gas-tight encapsulated interior, in which the stator 4 of the electric generator 2, in conjunction with a runner exposed to the outside environment 3. Here, a sea current with a high proportion of sediment, in particular sand and the like, lead to bearing wear. The same applies to wind turbines due to particles transported by the air flow. The inventors have therefore recognized that an advantageous further embodiment of the invention comprises a bearing and / or sealing rinse. A first embodiment is shown in FIG. First, according to the enlarged section in addition to the bearing 6 a sealing element 7, in particular a labyrinth seal provided. This suppresses the entry of sediments into the storage area and acts like a filter. However, due to the high torques acting on the turbine 1, slight relative movements can not be ruled out which cause a variation of the gap fit in the sealing elements 7. Therefore, according to a particularly preferred embodiment, a device is provided which causes a constant outflow of filtered ambient water or filtered ambient air out of the storage area. In the simplest case, only the filter elements 7 are flowed through here, so that penetration of abrasive media from the ambient flow is prevented. However, an additional bearing purging, which can be effected, for example, by causing an inflow of the filtered ambient medium in the gap region between the bearing elements 6.1 and 6.2 arranged laterally at an axial distance, is particularly preferred. According to an alternative embodiment, the water-lubricated bearings are replaced by bearings with grease lubrication, which can be performed as loss lubrication with environmentally friendly fats. The escaping grease carries abrasive solids from the bearings to the outside.

In accordance with the diagram simplified in FIG. 2, a filter 8, for example a cartridge filter, is provided in the housing hood 62 of the power generation plant. If the surrounding medium supplied to this filter 8 near the axis and then passed radially outward, by the fluid entrainment in the annular gap automatically creates a suction effect in the radially outwardly extending leads from the filter 8 to the gap 63, so that already by the rotational movement of the turbine 1 after outward flow is formed by the bearings 6.1, 6.2 or by the sealing elements 7. In addition, a filter pump 9 may be provided, which serves to press the filtered ambient medium reinforced in the gap 63 and thus to improve the storage or Dichtungsdurchströmung. The filter system 8 and the filter pump 9 form a pump-filter device. In a further embodiment, FIG. 3 shows a self-cleaning filter 8, based on the principle of centrifugal force, for producing a clean environment medium for the storage rinse. This has a plate-shaped element 10 in the housing cover 62, at the conically shaped outer walls 11 supplied contaminants in a rotational movement, driven by a coupling to the turbine, outwardly and thus away in the lateral direction from the rest of the filtered water flow away, being corresponding to the hood outside Outlet openings 64 may be provided for the rejected pollutants.

The pump-filter device may be unorganized outside of the sealed stator housing 5, which in turn simplifies encapsulation. Alternatively, the pump-filter device is placed in the sealed stator housing 5, which simplifies the precautions for corrosion protection of the pump-filter device. Preferably, the pump-filter device is arranged centrally in the stator housing 5 and has a hydraulic passage which opens an outlet in the region of the sealing elements 7 and / or the bearing 6.

In Figure 4, a further embodiment of the invention is shown, which connects the concept of a sealed, sealed generator housing 5 with a setting option for the turbine 1. In the event that the turbine 1 is designed in the form of a propeller, this adjustment is preferably an angular adjustment of the propeller blades 54. For a hydraulic adjustment, a fluidic connection between the stator housing 5 and the rotating components of the power generation system running on it is necessary to provide the hydraulic Supply components by an influx of working fluid from the interior of the stator housing. For this purpose, a hydraulic distributor with a rotary feedthrough on the stator housing 5 may be provided, which is not shown in detail in the figures. However, entirely on moving seal components on Instead of being able to dispense with the stator housing 5, a hydraulic pump 30 rotating with the rotating structural unit is used instead, which meshes with a stationary sprocket 32 via a pinion 31 which, for example, is connected to the stator housing 5. When circulating the turbine 1, the hydraulic motor 30 can be driven and actuated by not shown in detail hydraulic components, such as a reservoir and hydraulic valves, a hydraulic actuator 33 for blade angle adjustment at a set active engagement.

According to an alternative embodiment, which is shown schematically outlined in the upper part of Figure 4, an electric motor is used instead of a hydraulic drive, wherein the power supply for the electric actuators 21 via an inductive energy transfer from the fixed side to the circumferential side by means of a Spulenanordung. Accordingly, signals can be transmitted inductively. Advantageously, for this purpose, a coil ring 20.1, for example, in the fixed part, is provided, which is connected so that synchronously to the rotational movement of the rotating side in a co-moving single coil 20.2, a voltage can be induced. Within the skill of the art, a plurality of moving coils may be used instead of this single co-moving coil. It is also conceivable to receive the coil ring 20.1 in the rotating part and to provide one or more counter coils in the fixed part.

If an active adjustment of the turbine 1 is dispensed with for an alternative embodiment of the power generation system according to the invention, the power input can still be minimized in the case of load shedding if the turbine 1 is designed such that its activation depends on an applied generator torque and if it is omitted a return to a passive position is automatically effected. It is noteworthy that such a construction can be realized without complex control, when the generator torque is mechanically transmitted to an angle adjustment for the turbine blades. One possible embodiment of this principle is shown in FIGS. 5a and 5b, wherein a propeller-shaped turbine 1 is used and the two views are shown schematically simplified as plan views of the annular support structure 60 along the propeller axes. The annular support structure 60 comprises a first part 50 and a second part 51 carrying the magnetic components and in particular the permanent magnets of the rotor 3, over which the generator torque acts during normal operation. These two parts 50, 51 are rotatable relative to each other in the circumferential direction, being changed by such a relative rotation of the setting angle of the propeller blades. For this purpose, in FIGS. 5a and 5b, exemplary plan views of one propeller blade 54 each are shown, as well as its articulation points on the first part 50 and on the second part 51.

If now a rotatable mounting at a first pivot point 52 on the first part 50 in a windward area of the propeller blade 54 so as sketched in the figures 5a and 5b, the direction of flow of the water V _w is in the direction of a parallel position of the propeller blade act, that is, would only the first articulation point 52 is present on the first part 50, the result would be unscrewing the propeller blade 54 from the engagement position, for which the turbine 1 draws substantially no power from the ambient flow.

On the second part 51, via which the generator torque acts, a second articulation point 53 is provided, which serves to rotate by the supporting effect of the generator torque, the propeller blades 54 in the flow and thus to activate the turbine 1. The mode of action results from the comparison of FIGS. 5a and 5b. FIG. 5b shows the effect of the generator torque. This will act as a restoring force in the circumferential direction counter to the direction of rotation of the rotor 3 (see in this regard in Figure 5b, the direction of force F _Ma g on the magnetic components). If now the second articulation point 53 is displaced leewards with respect to the propeller blade axis, then the second part 51 and the relative rotatability occur due to the restraining force the first part 50 and the second part 51, an automatic tipping and thus in the flow of the rotor blades of the turbine 1. This case is shown in Figure 5b, wherein the connecting axis of the first pivot point 52 and the second pivot point 53 a certain angle of attack against the Flow direction Fw will take, that is, the propeller blade 54 can absorb power from the ambient flow and drive the generator. Without loss of power to the electric generator, that is, in the case of a load shedding, the selectively acting only on the second part, the circulation of the turbine 1 braking force falls away from the generator torque and acting on the profile of the propeller blades flow forces are returning to the in FIG 5a effect, rotated from the flow position. Accordingly, the turbine 1 can be stopped for maintenance.

The underlying concept according to which the turbine 1 is activated and deactivated on the basis of the relative movement of two subcomponents of the support and support structure and on one of these two parts during operation a higher, restrained generator torque acts compared to the other part, in detail in the frame be further developed by the expert skills. For the embodiment shown in Figure 5a and 5b, the second, leeward and braked by the generator torque pivot point 53 have an adjustable bearing, which allows a certain relative movement along the blade profile for the pivot point, which for realizing a combined relative movement of the first part and the second part 50th , 51 and the rotational movement of the propeller blade 54 about its propeller axis is necessary. Schematically simplified, a slot arrangement is shown for this purpose in FIGS. 5a and 5b, along which the second articulation point 53 can slide, depending on the prevailing angular position. Furthermore, it is preferred to limit the relative movement between the first part 50 and the second part 51. For this serve stops. A first stop serves in this case for the non-active position according to FIG. 5a to maintain a certain minimum propeller blade angle which, even in the case of idling, enables a minimum power consumption by the turbine, which serves to prevent the Frictional forces to overcome so far that a slow rotational speed for idling operation is present. However, the choice of the stop must reliably prevent a turbine run-up being prevented even with the maximum possible applied flow. Furthermore, a second stop for the operating position shown in Figure 5b may be provided, which serves to set a maximum propeller blade angle, so that the two pivot points 52 and 53 are relieved.

The above-described concept of self-control of the turbine via the generator torque and the automatic possibility of reaction to a load shedding makes it possible to design an additional brake with a small footprint for securing the turbine. In addition, there is an efficient braking effect by friction elements, which are formed in the region of the circumference of the rotor, and act on the corresponding counter-elements from the stator housing. In an external rotor, which is mounted on the stator housing and thus on a large outer diameter, this braking effect can be achieved by simple and therefore again low-maintenance components.

The above principle can be used in a further design to use the generator torque as a power source and as a control signal for adjusting the angle of the propeller blades. In addition, the limit stops can be adjusted actively.

LIST OF REFERENCE NUMBERS

1 turbine

2 electric generator

3 runners

4 stator

5 stator housing

5.1 wall area

6 storage

6.1, 6.2 bearing components

7 sealing element

8 filter system

9 filter pump

10 plate-shaped element

11 conical outer walls

20.1 coil wreath

20.2 single coil

30 hydraulic motor

31 pinions

32 sprocket

33 hydraulic actuator

50 first part

51 second part

52 first articulation point

53 second articulation point

54 propeller blade

60 annular support structure

61 axis

62 housing cover

63 gap

Claims

claims

A power plant for recovering electrical energy from a flow of water or air, comprising:

1.1 a turbine (1);

1.2 an electric generator (2), with a coaxial arrangement of rotor (3) and stator (4), wherein the rotor (3) is an external rotor and part of an annular support structure (60) for the turbine (1) and the stator ( 4) is housed in a sealed relative to the surrounding medium stator housing (5) and wherein a wall portion (5.1) of the sealed stator housing (5) in the region of the gap (63) between the rotor (3) and stator (4) runs so that the rotor (3) is arranged radially outside the sealed stator housing (5) and the magnetic interaction between the rotor (3) and stator (4) through this wall region (5.1) is carried out therethrough;

1.3 a bearing (6) for the runner (3) comprehensive annular support structure (60), wherein the bearing (6) adjacent to the gap (63) between the rotor (3) and stator (4) is arranged and on the outer circumference of the sealed stator housing (5) is supported.

2. Power generation plant according to claim 1, characterized in that the bearing (6) comprises water-lubricated bearings.

3. Power generation plant according to claim 1 or 2, characterized in that the bearing (6) is formed mehrreihig, wherein each other in the axial direction spaced first and second bearing components (6.1, 6.2) of the bearing (6) the gap (63) between runners ( 3) and laterally limit the stator (4).

4. Power generation plant according to at least one of claims 1 to 3, characterized in that the electrical generator (2) is designed as a ring generator.

5. Power generation plant according to at least one of claims 1 to 4, characterized in that the electrical generator (2) is designed as a high-pole synchronous generator, wherein the rotor (3) comprises permanent magnets.

6. Power generation plant according to at least one of claims 1 to 5, characterized in that the wall region (5.1) of the sealed stator housing (5) in the gap (63) between the rotor (3) and stator (4) made of a corrosion-resistant, non-magnetic material and especially preferably made of a corrosion-resistant, non-ferromagnetic material.

7. Power generation plant according to claim 6, characterized in that an austenitic steel is used as material for the wall area (5.1).

8. Power generation plant according to at least one of claims 1 to 7, characterized in that the system control and / or components of the power electronics and / or frequency converter are housed within the sealed stator housing (5).

9. Power generation plant according to at least one of claims 1 to 8, characterized in that the storage (6) sealing elements (7) are associated, which seal the storage (6) towards the outside against the ingress of abrasive substances.

10. Power generation plant according to claim 9, characterized in that are used as sealing elements (7) labyrinth seals.

11. Power generation plant according to at least one of claims 9 or 10, characterized in that a purging device for generating an outwardly directed flow through the sealing elements (7) is provided with filtered ambient medium.

12. Power generation plant according to at least one of claims 1 to 11, characterized in that it is provided as a rinsing device for rinsing the bearing (6), wherein filtered ambient medium is used as rinsing medium.

13. Power generation plant according to at least one of claims 11 to 12, characterized in that the purging device comprises a pump-filter device which serves for the removal and filtering of surrounding medium.

14. Power generation plant according to claim 13, characterized in that the pump-filter device is arranged outside of the stator housing (5) and has an at least indirect mechanical drive connection to the turbine (1).

15. Power generation plant according to claim 13, characterized in that the pump-filter device is arranged in the interior of the sealed stator housing (5).

16. Power generation plant according to one of claims 13 to 15, characterized in that the pump-filter device operates on the centrifugal principle.

17. Energy generation system according to at least one of the preceding claims, characterized in that the turbine (1) comprises at least two rotor blades, which is associated with a device for blade angle adjustment, wherein the device for blade angle adjustment comprises a self-sufficient power generation unit or a device which is supplied by inductive coupling from the liquid-tight sealed stator housing (5) from energy.

18. Energy generating installation according to claim 1, characterized in that the turbine (1) has movable elements for the power consumption and these are brought into the active position for power consumption by the action of the generator torque and in the event of a dropping generator torque the flow is returned to a passive position where the power input is reduced.