US20080101865A1

US20080101865A1 - Hydrodynamic Drive Train for Energy Converters that use Ocean Currents

Info

Publication number: US20080101865A1
Application number: US11/720,564
Authority: US
Inventors: Andreas Basteck; Martin Tilscher
Original assignee: Voith Turbo GmbH and Co KG
Current assignee: Voith Turbo GmbH and Co KG
Priority date: 2004-12-03
Filing date: 2005-11-30
Publication date: 2008-05-01
Also published as: WO2006058725A1; DE102004058258A1; KR20070085927A; CN101061313A; EP1817497A1

Abstract

The invention relates to an energy generation System for obtaining electric energy from an ocean current. Said System comprises a drive train comprising an input shaft and an Output shaft, the input shaft being driven at least indirectly by a water turbine and the Output shaft at least indirectly driving an electric generator, which is connected to an electric network. The electric network has an essentially constant network frequency and the drive train comprises an Output branching gear with a first Output branch and at least one second Output branch. The first Output branch and the second Output branch are interconnected by means of the Output branching gear and a hydrodynamic component.

Description

The invention relates to a device and a method for creating electrical energy from an ocean current, wherein the created electrical energy is fed in particular into an electrical network with a mainly constant network frequency.
Ocean currents offer great potential for obtaining electrical energy without releasing emissions during energy creation. Such ocean currents are either available permanently, e.g. the Gulf Stream, or they are caused by tides. In the case of the latter, areas are particularly interesting in which the tidal range is particularly strong and in which geographical uniquenesses, such as narrow flow-through areas or particularly molded bay areas, lead to a pronounced ocean current. If there are special conditions, then the state of the waves can be used to drive underwater current power machines. Such conditions can be created through artificial means, such as inlet pools, through which the energy inherent to the waves can be taken advantage of.
One of the uniquenesses in the driving of a water turbine by an ocean current is the temporally variable power input. Such temporal fluctuations also occur in permanent flow areas. This condition is at first astounding. However, measurements in current power machines with a normal dive depth of a several tens of meters, e.g. in the Gulf Stream, show that a temporally variable power input should be expected for these types of power generation systems. On one hand, this is due to weather influences and the resulting wave movements. On the other hand, measurements have demonstrated the occurrence of turbulences in ocean currents. These are present in the ocean both in the case of tidal currents and permanent flow patterns and are particularly pronounced in water that is up to 50 meters deep, which is preferably provided for energy generation.
In addition to the temporal variation of the kinetic energy available in an ocean current, uniquenesses with respect to the characteristics and dynamic in the mechanical energy conversion of the kinetic energy of the current medium into the kinetic energy of a hydropower turbine are to be taken into consideration. Thus, characteristics inherent to the system, which associate an optimal speed/torque ratio with a certain current speed of the ocean current according to the quick run number for the power input, exist for the power conversion on the input shaft, which in turn depends on the geometry and the design of the power input.
These characteristics of the power conversion are also present in other current machines, such wind power machines. However, current power machines for extracting energy from an ocean current are different from wind power machines, since a high torque has an effect on the power intake based on the higher density of the current medium and this is small in size compared to the other components of the energy generation system, e.g. a drive train and the electrical generator as well as the mechanical holding structures. It is thus necessary to also design the drive train and the electrical machine of the energy creation system to be as small as possible in order to improve the overall system from a technical flow perspective. With respect to the electrical generators used in the energy generation system, the size reduction strived for is prevented by the fact that the power intake driven by the ocean current revolves at a relatively lower speed of typically less than 20 rpm. Without the interconnection of drives between the water turbine and the electrical generator, a low velocity of the electrical machine leads to an increase in the overall size.
If an energy generation system driven by an ocean current feeds electrical energy to an electrical integrated network, which has a fixed network frequency, then further requirements result. If a variable speed of the power intake, i.e. the water turbine, of the energy generation system is assumed, then an electrical generator operated at a variable speed also requires the use of frequency converters for infeed into the electrical integrated network. These activate the electrical generator with the required frequency or ensure the compensation of a difference for the existing network frequency. This approach is wrought with problems in this respect, since the uniquenesses of the power conversion characteristics in current power machines can only be designed inadequately with frequency converters. Much effort is required to obtain an adequate network infeed quality, in particular with respect to the harmonic oscillation load and the creation of idle power.
If an alternate path is used instead and the water turbine is designed such that speed constancy of the power intake is ensured through the placement of paddle-wheel angles, then an electrical generator driven at least indirectly by the power intake can be designed with a fixed speed. Such fixed-speed energy generation systems can easily be impressed on an electrical integrated network with the use of asynchronous generators based on the principle-determined slip. However, the disadvantage is that the speed of the power input results in decreased energy efficiency through the placement of the paddle-wheel position for holding it constant, i.e. the power input cannot extract the maximum energy from the ocean current.
The object of the invention is to specify a device for the generation of electrical energy from an ocean current as well as a method for the operation the same, which overcomes the disadvantages described above. In particular, this type of energy generation system should be able to be operated in the partial-load operational range with a variable speed of the power intake with a simultaneously constant speed of the electrical generator. Furthermore, the energy generation system should also allow the realization of other operating states. In particular, a speed regulation of the power intake should be possible above the speed threshold, in order to prevent the occurrence of cavitation and to protect the fish population from the damaging rotating speed. In the performance range of the speed constancy, surge reduction and short-term energy storage for collecting and assessing load surges and energy peaks should be possible. Furthermore, the energy generation system in the full-load area should be able to realize torque regulation as well as special operating states such as shut down and the reaction to a load rejection.
In order to solve the object, the inventor first identified that a water turbine driven by an ocean current via a drive must be connected with a quick running electrical generator in order to be able to design the electrical generator to be sufficiently small with respect to the water turbine. Also according to the invention, the connection between the water turbine and the electrical generator is produced by means of a drive train, which comprises a hydrodynamic drive. On one hand, the hydrodynamic drive serves to transmit speed, on the other hand, for the implementation of the speed variability of the water turbine with the simultaneous speed constancy of the electrical generator. This is effectuated through the regulation and control of at least one hydrodynamic component in the hydrodynamic drive, wherein it is preferred in particular that the hydrodynamic drive is designed as a power branching drive.
According to an advantageous embodiment, the drive train according to the invention comprises an overriding drive, such as a planetary drive, for the power branching into a first power branch and at least one second power branch. A quickly rotating shaft is arranged in the first power branch to drive an electrical generator. The second power branch is at least indirectly connected with the first power branch via a hydrodynamic component, for example a hydrodynamic converter, a hydrodynamic coupling or a Trilok converter. Through the regulation and control of the power flow via the hydrodynamic component and the degree of the coupling between the first power branch and the second power branch, the speed variability of the power branch and thus a maximum energy extraction from the ocean current can be ensured with a simultaneously constant speed of the electrical generator.
When the water turbine is started from the stopped position, the electrical generator is first accelerated until it reaches its target speed. In the normal mode then reached, the network frequency impresses a target speed depending on the number of poles on the electrical generator and thus the first power branch. A typical speed of the electrical generator is for example 1500 rpm, so that small electrical generators can be used. Moreover, an effective operation of a hydrodynamic component connected at least indirectly with the first power branch, which is assigned to the second power branch, is possible with such high speeds on the shaft of the first power branch. Due to the power flow regulated and controlled by the hydrodynamic component between the first and the second power branch, it is now possible to drive the water turbine with a speed that is optimal for the power conversion.
If a hydrodynamic servo converter is used as the hydrodynamic component for the creation of a connection between the first and the second power branch, it has been shown that the characteristics of the servo converter match the characteristics of the power input with respect to the speed/power and the speed/torque ratio. This can be used to realize a self-regulating effect.
A drive train with a servo converter can be designed such that the water turbine can be driven optimally with respect to it speed with the simultaneously constant rotating speed with a certain, mainly constant setting of the guide wheel of the servo converter. Thus, when using a servo converter in the power-branched drive train of an energy generation system according to the invention, no regulation in the actual sense is necessary for the setting of an optimal speed of the water turbine.
In order to avoid the formation of cavitation bubbles, a maximum speed of the water turbine cannot be exceeded. Moreover, the risk of injury to ocean life increases with the increasing speed of the water turbine. As of a certain speed threshold, which in detail depends on the design and the size of the water turbine as well as the available flow direction and current speed, a limitation of the rotating speed of the water turbine is thus performed according to the preferred designed of an energy generation system or according to a preferred operating procedure. Depending on the type of the design, one of these two factors will be decisive in determining an upper speed threshold for the water turbine of the energy generation system.
For the energy generation system according to the invention, the speed guidance for the speed limitation of the water turbine is effectuated by means of the selected setting for the hydrodynamic component in the hydrodynamic drive. If for example a servo converter is used and if the drive train of the energy generation system according to the invention is advantageously designed in a power-branching manner, then the power transmission from the first power branch to the second power branch can be effected via a change in the setting of the guide wheel of the servo converter. In general, any guide wheel setting in which the water turbine is optimally driven is abandoned.
A threshold in the power intake is also assigned to the threshold speed in an optimal power intake, i.e. a power intake along the parabolica. In the case of variations in the input power, which lie above this power threshold, it is necessary to regulate the hydrodynamic component in the hydrodynamic drive in order to comply with the speed constancy of the water turbine. The required sensors for capturing the speed of the water turbine and the formation of a regulator affecting the hydrodynamic components can be realized in the framework of expert ability.
A special advantage of the energy generation system according to the invention with a hydrodynamic drive is that for the operating state of a speed-regulated water turbine fluctuations in the power input and in particular temporally quickly changing load fluctuations can be damped and its energy input can be used for short-term acceleration of the water turbine and thus as a short-term energy storage. This property originates from the fact that a certain operating point is determined through the regulated and controlled setting of the hydrodynamic component. Fluctuations in the speed of the water turbine are then possible around this operating point. For this, a fluctuations width of±10% and preferably±5% and even more preferably±3% are still tolerated.
Now, if a load surge hits the water turbine due to a turbulence effect, the speed will then increase to a certain extent and thus the additional power made available in the short term flows into the system. For one, the purpose of this is that the additional power can be used and, on the other hand, that load surges are absorbed and do not need to be taken in by the mechanical holding structures. This has an advantageous effect on the reduction of the torque surges in the drive train and thus on the durability of the energy generation system.
In the partial load area, in which the energy generation system according to the invention is operated optimally along the parabolica and advantageously as of a certain speed threshold in a speed-limited or speed-driven manner, the full-load area was connected. This is characterized in that a maximum torque is achieved on the power input. Above this torque threshold, a torque regulation for the water turbine takes place, wherein additional servo elements, which limit the power taken in by the water turbine, are used for the energy generation system according to the invention in addition to the setting of the hydrodynamic components in the drive train. In an advantageous embodiment, a power limitation, which has slow reaction times, is achieved through a change in the angle position of the paddle wheels of the water turbine, while through the setting of the hydrodynamic component in the case of a servo converter through the setting of the guide wheel, a short term power limitation is performed for the electrical generator. The slow system of the angel adjustment of the paddle wheels of water turbine can thus be bridged in the short term with the more quickly adjustable servo converter.
If a hydrodynamic coupling is used as the hydrodynamic component instead of a servo converter, then no self-regulation can be realized for the power-optimal guidance of the water turbine. In this case, the setting of the hydrodynamic coupling must be actively regulated in order to guide in the partial-load area the speed of the water turbine in a power optimal manner along the parabolica. The advantage of using a hydrodynamic coupling instead of a servo converter is however an increase in the power efficiency of the drive train, in particular under full-load conditions. If a Trilok converter is used as an alternative hydrodynamic component, there are also advantages in terms of efficiency in certain power areas or operating phases with respect to a hydrodynamic servo converter.

The invention is described in greater detail below based on figures. The figures show the following:

FIG. 1 shows an energy generation system according to the invention in a schematically simplified manner.

FIG. 2 shows a preferred embodiment of the drive train of the energy generation system with a first and a second power branch.

FIG. 3 shows three operational areas of an energy generation system according to the invention in the speed/torque diagram.

FIG. 4 shows the self-regulation effect when using a hydrodynamic servo converter in the drive train for the realization of a power-optimal speed guidance in the part-load area.

FIG. 5 represents the setting of the guide wheel of a hydrodynamic servo converter during the transition between the individual operating ranges from FIG. 3.

FIG. 6 illustrates the short-term energy storage and the load-surge reduction of an energy generation system according to the invention in the speed-regulated range.

FIG. 7 shows in a schematically simplified manner three regulation levels for the operation of an energy generation system according to the invention.

FIG. 1 shows the energy generation system according to the invention in a schematically simplified manner. An electrical generator 11, which is coupled with an electrical network 60, is hereby driven at least indirectly by means of a water turbine 3. The water turbine 3 can be designed within the framework of expert ability. For example, a two-or multi-blade propeller structure can be selected. Furthermore, additional structures can be provided around the water turbine, which serve to protect or guide the current. According to the invention, a hydrodynamic drive train 1 is used between the water turbine 3 and the electrical generator 11. A hydrodynamic drive train 1 is to be understood in the present invention as a power-branched drive train, which comprises a first power branch 7 and at least one second power branch 18. A power branching drive used for the power branching of the power fed to the hydrodynamic drive train on the drive side. For example, this can be a planetary wheel set. On the output side of the power branching drive 5, a connection is established between the first and the second power branch 7, 18 by means of a hydrodynamic component, which is assigned to the second power branch so that it is possible to impress different rotating speeds on the water turbine 3 starting from a constant rotating speed of the electrical generator 11.
The energy generation system can also have optional components. These are additional drives, which are located upstream or downstream from the hydrodynamic drive train. In FIG. 1, a transmission stage 4 designed as a planetary wheel set serves as a first transmission of the speed of the water turbine. Furthermore, a transmission element 50 that comprises a coupling and/or a brake can be provided between the hydrodynamic drive train 1 and the electrical generator 11. These can also be located between the additional drive 4 and the hydrodynamic drive train 1.
The mechanical holding structures for the energy generation system are not shown in detail in FIG. 1. An embodiment is preferred in which the components shown in FIG. 1 are combined as a structural unit and encased in a water-tight housing so that this structural unit can be entirely submersed. This structural unit can then be delivered along a support structure up to a depth preferred for the energy generation.
FIG. 2 shows an advantageous embodiment of the hydrodynamic drive train 1 of an energy generation system according to the invention. Its input shaft 2 is thereby at least indirectly connected with the water turbine 3 of a wind power system according to the invention. In the present case, a drive 4 with a constant transmission ratio is placed between the rotor 3 of the wind power machine and the input shaft 3. In the exemplary embodiment shown here, a planetary drive is used as the power branching drive 5 of the drive train 1, wherein the input shaft 2 is connected with the planetary wheel carrier 6. There are now two power branches in the power branching drive 5; the first power branch 7 feeds power via the sun wheel 9 of the planetary wheel drive to the output shaft 10 of the drive train. This output shaft 10 drives at least indirectly the electrical generator 11 and is connected with the hydrodynamic servo converter 12. For this, the output shaft is at least indirectly connected with the pump wheel 13 of the hydrodynamic servo converter 12. A guide wheel with adjustable blades, with which the power flow to the turbine wheel 14 can be adjusted, is used as the reaction member 15 in the hydrodynamic converter 12. A return power flow in turn takes place via the turbine wheel 14, which is fed via a second, fixed planetary wheel set 16, and in turn has an effect on the outer wheel 17 of the power branching drive 5 and affects the transmission ratio. This represents the second power branch 18 of the power branching drive, which serves to return power.
Three main operational areas are differentiated for the operation of the energy generation system according to the invention. These are shown in FIG. 3. The power obtained from the water turbine is hereby represented in any units depending on the speed of the water turbine, also in any units.
In an area labeled with I, the energy generation system is operated at partial load. This begins as of a certain speed and ends at a certain speed threshold Dmax. The curve shown in FIG. 3 in operational range I represents a target curve, which shows a power-optimal speed guidance of the water turbine 3. An optimal speed of the water turbine 3 is assigned to a certain power input. If the water turbine 3 rotates with a lower or a higher speed than the optimal speed, then no optimal power of the ocean current can be obtained from the energy generation system. In the present application, the term speed guidance along a parabolica is also used for the power-optimal speed guidance in the operating range I.
For the energy generation system according to the invention, an electrical generator 11 with a constant, preferably fast rotating speed, is used. Synchronous generators that were once coupled with the network frequency are support in their rotating speed by the electrical integrated network 60. This applies in a sufficient scope also to asynchronous generators, if they are operated in a rigidly running linear area. Starting from this constant speed of the electrical generator 11, the input-side speed of the drive train and thus the speed of the water turbine 3 is guided through the control and/or regulation of the working connection between the first power branch 7 and the second power branch 18 of the drive train 1, i.e. the power flow over the hydrodynamic components, such that it always rotates with a power-optimal speed.
If a hydrodynamic servo converter 12 is used as the hydrodynamic component, there is the advantage that no regulation in the actual sense but rather a system-inherent self-regulating effect can be used for the power-optimal speed guidance of the water turbine 2. This is illustrated in FIG. 4. Curve E thereby represents the power taken in by the wind rotor; curve F is the power on the sun wheel 9; curve G is the power transmitted by the drive train; and curve H indicates the power flowing back from the hydrodynamic converter 12 to the power branching drive 5 via the second power branch 18. The setting of the guide wheel 15 of the hydrodynamic servo converter is also shown. It can be seen that in the case of an optimal power input along the parabolica, which can be recreated through the characteristics of the drive train 2, can be operated with a guide wheel position of the hydrodynamic converter 12 mainly remaining over the entire partial-load area represented. Below, the setting is referred to as the adjusted setting of the hydrodynamic converter 12. Thus, no regulation of the guide wheel is needed in order to achieve the constancy of the output speed of the drive train for the loading of the electrical generator 11 with simultaneously variable optimal water turbine speed. We thereby refer to the fact that the steepness of the parabola characterizing the power output can be set through the transmission dimensioning of the components of the power branching drive in connection with the dimensioning of the hydrodynamic converter. This characteristic of the drive train 1 according to the invention is called self regulation below.
The operating range I, in which kinetic energy is removed through the power input of the energy generation system according to the invention in a power-optimal manner under part-load conditions, could now be guided along the power parabolica up to the full-load area with a constant speed. However, in the case of this type of operational management, a speed threshold Dmax, which is to be observed in order to avoid cavitation or to protect of fish, is normally exceeded as of a certain power input. As of this threshold speed Dmax, the operating range I is thus preferably abandoned and switched over to an operating range II, which is characterized by the holding constant of the speed of the water turbine.
For the embodiment of the drive train 1 with a hydrodynamic servo converter 12 as the hydrodynamic component, the transition between the individual operating ranges is shown in FIG. 5. In the operating range I with power-optimal speed guidance, a mainly constant remaining guide wheel position, in the present case at 25% of the adjustment travel is used in the sense of the self-regulation effect. In the case of the transition from the operating range I to the speed-limited operating range II, this optimal guide wheel position is abandoned and the guide wheel of the hydrodynamic servo converter 12 is readjusted depending on the power input to the water turbine 3 such that the water turbine speed remains mainly constant and only the torque taken in by the water turbine 3 and thus the power taken in vary. In the operating range II, a certain speed progression, preferably a particularly steep speed progression, can be selected in one embodiment instead of an actual speed threshold. Characteristic for the operating range II is that the power-optimal speed guidance is abandoned.
Furthermore, the transition of the speed-limited operating range II on the torque-limited operating range III is shown in FIG. 5. The control and/or regulation for the effectuating a speed constancy is thereby abandoned above a threshold torque on the wind turbine 3. In order to now prevent an undesired increase in the power generation of the water turbine 3 in the operating range III, the power input through the water turbine 3 is limited with additional measures, for example a change in the paddle-wheel position of the water turbine 3 or an adjustment of an associated guide apparatus and another speed increase for the torque limitation is thereby prevented. For the bridging of the slow regulation of the paddle-wheel position of the water turbine 3 in the case of a power increase in the operating range III, the guide wheel position of the hydrodynamic servo converter 12 is first changed in order to avert short-term torque surges or increases through the drive train, which causes a short-term speed increase in the water turbine. This is however limited by the paddle-wheel adjustment of the water turbine 3 taking place in the second step. This is not shown in detail in FIG. 5.
FIG. 6 now shows the case of the operating range II, in which a certain target speed of the water turbine 3 is impressed through the deadjustment of the hydrodynamic servo converter 12 above a certain speed threshold range. The represented set of curves represents different guide wheel positions (H=25%-100% adjustment travel). In the present case, the hydrodynamic servo converter is adjusted with a guide wheel position of H=25% adjustment travel. It can be seen from FIG. 6 that different working point can be selected through the deadjustment of the hydrodynamic servo converter 12. In the simplest case, the speed is restricted in this manner. It is also possible to adjust the working points for the desired speed of the water turbine 3 along a curve, which depends on the torque taken in by the water turbine 3. It is hereby possible to adjust in particular the softness of the drive train at the border with full-load operation.
Around each working point set through the deadjustment of the hydrodynamic servo converter in the operating range II, there is in turn the parabolic power intake characteristic, which is run through in the case of varying flow speeds. This situation is shown in FIG. 6. Please note that the setting of a certain working point can be performed slowly, i.e. in the second to minute range, and depends on the average flow speed. The possible fluctuations around this working point, which are balanced by system characteristics of the drive train when using a hydrodynamic converter 12 through self-regulation, are short-term effects, which occur through fluctuations. This fluctuation amplitude should not exceed±30% of the desired speed in the working point, preferably±10% and even more preferably±5%.
In addition to the operating ranges I-III described above, additional operating states can also occur, for example the startup or shutdown of the energy generation system, the synchronization of the electrical generator with the network frequency, a load rejection, an emergency stop or special operating conditions, for example a test or protection mode. In order to implement the different operating ranges and operating states, an embodiment of the regulation and control for the energy generation system is preferred in the form of a hierarchical structure with a subdivision into three regulation levels. This is outlined in FIG. 7. The first regulation level is the energy generation system itself. The drive train of the energy generation system is hereby preferably designed with a hydrodynamic servo converter as the hydrodynamic component, which leads to a self-regulation. Nevertheless, alternative hydrodynamic components like a hydrodynamic coupling or a Trilok converter are also conceivable for reasons of efficiency. In this case, this system-inherent self-regulation must be replaced by an active regulation through speed guidance of the water turbine. This first regulation level is overlaid by the second regulation level, which includes the regulator for the paddle-wheel position, the adjustment of the hydrodynamic component and a regulator for the power electronics of the generator. In this level, a target vs. actual value comparison takes place for each of the named regulators, whereupon corresponding adjustment signals are output.
According to the invention, not every regulator of the second regulation level is activated for all operating ranges or operating states. A control of the regulator activation as well as a regulator weighting or a graduated switching between individual regulators is effectuated by the third regulation level. This not only selects the variables to be regulated depending on the operating state or the operating range, but it is also possible to use different regulators or different regulator settings for one and the same variable, e.g. the paddle-wheel position. The regulation characteristics and the regulation speed can hereby be adjusted based on each special situation. Furthermore, an adjustment of the regulator target values and the selected working points also results via the third regulation level as a superordinate control level.

Claims

1. Energy generation system for extracting electrical energy from an ocean current, comprising

a drive train with an input shaft and an output shaft;

the input shaft is driven at least indirectly by a water turbine;

the output shaft drives at least indirectly an electrical generator, which is connected with an electrical network, wherein the electrical network has a mainly constant network frequency;

the drive train comprises a power branching drive with a first power branch and at least a second power branch;

the first power branch and the second power branch are connected with each other via power branching drive and a hydrodynamic component.

2. Energy generation system in accordance with claim 1, characterized in that the hydrodynamic component is a hydrodynamic servo converter or a hydrodynamic coupling or a Trilok converter.

3. Energy generation system in accordance with claim 2 characterized in that the hydrodynamic component is attached to the output side of the power branching drive.

4. Energy generation system in accordance with claim 1, characterized in that the hydrodynamic component is connected at least indirectly with the drive shaft of the electrical generator.

5. Energy generation system in accordance with claim 1, characterized in that the electrical generator is designed as a quick running generator.

6. Energy generation system in accordance with claim 1, characterized in that a transmission drive is arranged between the water turbine and the input shaft of the drive train.

7. Energy generation system in accordance with claim 1, characterized in that additional stand drives are provided for the speed adjustment in the first power branch and/or the second power branch.

8. Energy generation system in accordance with claim 1, characterized in that the water turbine, the drive train and the electrical generator is designed as a structural unit that is submersible.

9. Method for the operation of an energy generation system in accordance with claim 1, characterized in that the energy generation system in the partial load area of the water turbine impresses a power-optimal speed.

10. Method for the operation of an energy generation system in accordance with claim 1, characterized in that the speed of the water turbine is guided above a speed threshold (Dmax) along a target curve.

11. Method for the operation of an energy generation system in accordance with claim 9, characterized in that the speed is maintained mainly constant.

12. Method for the operation of an energy generation system in accordance with claim 1, characterized in that the speed is variable in a certain speed interval in the case of load surges.

13. Method for the operation of an energy generation system in accordance with claim 1, characterized in that, above a maximum torque on the water turbine, the torque transferred to the electrical generator is limited by the adjustment of the hydrodynamic component.

14. Method for the operation of an energy generation system in accordance with claim 13, characterized in that, above the maximum torque on the water turbine, the power extracted from the ocean current by the water turbine is limited.

15. Method for the operation of an energy generation system in accordance with claim 14, characterized in that the power limitation is effectuated by the adjustment of the paddle wheels of the water turbine and/or one of the guide apparatuses assigned to the water turbine.

16. Energy generation system in accordance with claim 3 characterized in that the hydrodynamic component is attached to the output side of the power branching drive.

17. Energy generation system in accordance with claim 2, characterized in that the hydrodynamic component is connected at least indirectly with the drive shaft of the electrical generator.

18. Energy generation system in accordance with claim 3, characterized in that the hydrodynamic component is connected at least indirectly with the drive shaft of the electrical generator.

19. Energy generation system in accordance with claim 2, characterized in that the electrical generator is designed as a quick running generator.

20. Energy generation system in accordance with claim 3, characterized in that the electrical generator is designed as a quick running generator.