Kite system and method for operating a kite system

Abstract

A kite system comprising a kite (14), comprising a gondola (25) and comprising a line tree (24), wherein the kite (14) is joined to the gondola (25) by means of the line tree (24). The line tree (24) comprises a branching block (27, 28). The branching block (27, 28) is connected to the gondola (25) by means of a control cable (35, 36). The line tree (24) comprises a first cable section (48), which extends between the branching block (27, 28) and a first attachment point (61) of the kite (14). The line tree (24) comprises a second cable section (49), which extends between the branching block (27, 28) and a second attachment point (62) of the kite (14). The length of the control cable (35, 36) between the gondola (25) and the branching block (27, 28) is changed by a control mechanism (39). The length of the first cable section (48) between the branching block (27, 28) and the first attachment point (61) is changed by a trimming mechanism (40). The invention also relates to a method for operating a kite system.

Description

[0001] Kite system and method for operating a kite system

[0002] The invention relates to a kite system and a method for operating a kite system.

[0003] A kite, held by a towing rope, can be moved along flight paths that are essentially perpendicular to the towing rope by appropriately adjusting its aerodynamic properties. As the kite moves along the flight paths, a tensile force is exerted on the towing rope. This tensile force can be used, for example, to generate electrical energy or as propulsion for a ship.

[0004] During normal operation of the kite system, where a high pulling force is desired, the kite is steered to move within a wind window within which the wind exerts a strong force on the kite. Until now, it has been common practice to steer the kite to the edge of the wind window for retrieval, where the force exerted by the wind on the kite is significantly smaller (WO 2007 / 112 993 A1). This results in a loss of time because the kite must first travel the distance to the edge of the wind window before being retrieved.

[0005] The invention is based on the object of presenting a kite system and a method for operating a kite system that avoid these disadvantages. This object is achieved by the features of the independent claims. Advantageous embodiments are specified in the subclaims.

[0006] A kite system according to the invention comprises a kite, a gondola and a line boom. The kite is connected to the gondola via the line boom. The line boom comprises a branching block which is connected to the gondola via a control cable. The line boom comprises a first tension cord which extends between the branching block and a first pivot point of the kite. The line boom comprises a second tension cord which extends between the branching block and a second pivot point of the kite. The kite system is equipped with a control mechanism for changing the length of the control cable between the gondola and the branching block. The kite system is equipped with a trimming mechanism for changing the length of the first tension cord between the branching block and the first pivot point.

[0007] The invention proposes coupling a trimming mechanism to the control mechanism of the kite system. The control mechanism can be designed to influence the flight direction of the kite. The trimming mechanism can be designed to influence the angle of attack of the kite. The coupling between the control mechanism and the trimming mechanism makes it possible to change the angle of attack while at the same time maintaining the controllability. For example, the kite can be brought into a different angle of attack and, in this state, steered along predetermined flight paths without the control mechanism having to be adjusted to the changed angle of attack.

[0008] The kite system can include a towing rope that extends from the gondola to a power absorption point on Earth. The power absorption point can, for example, be located on a ship, so that a tensile force acting on the power absorption point acts as a propulsion force for the ship. In another embodiment, the tensile force of the kite acts via the power absorption point on a generator to generate electrical energy. The kite can move away from the power absorption point while electrical energy is being generated, so that the generator is powered by movement of the towing rope. If the kite system is used to operate a ship, the distance between the gondola and the power absorption point can remain constant.

[0009] The kite's current flight direction can be at a right angle to the direction of the pull rope, i.e. the direction in which the pull rope pulls on the gondola. The control cable can be arranged in a plane that is orthogonal to the current flight direction. Operating the control cable can trigger a rolling movement of the kite, with which the entire kite or a section of the kite is pivoted around an axis parallel to the flight direction. Such a rolling movement of the kite results in the kite's flight path curving, i.e. the kite flying a turn. As the kite flies through the turn, it rotates around the direction of the pull rope.

[0010] In one embodiment, the kite system comprises a first control cable and a second control cable, the first control cable acting on a different section of the kite than the second control cable. Each of the control cables can have the features mentioned of the one control cable. The first control cable and the second control cable can be arranged on two sides of a longitudinal center plane of the kite which is tensioned by the tow rope and the direction of flight. The control mechanism can be set up such that the first control cable and the second control cable are coupled to one another. The coupling can be designed such that the first control cable is shortened when the second control cable is lengthened, and vice versa. The kite system can be set up so that the kite performs a rolling movement.

[0011] The trim mechanism can be designed to trigger a pitching movement of the kite around a pitch axis. A pitching movement is a movement in which the kite or part of the kite is rotated around a pitch axis that forms a right angle with the direction of flight. The pitch axis can also form a right angle with the direction of pull, i.e. the direction in which tensile forces are transferred between the kite and the branching block. Due to the curved shape of the kite, the local direction of pull depends on the distance to the longitudinal center plane of the kite. The angle between the direction of the pull rope and the local direction of pull becomes greater the greater the distance between the pivot point and the longitudinal center plane. The pitching movement therefore always refers to a local pitch axis that applies to the longitudinal plane of the kite, within which the pivot points involved in the pitching movement are arranged.

[0012] The pitch axis may be at a constant distance from the junction block. The kite system may include a line extending between a pivot point located at the pitch axis and the junction block. The line may form a fixed-length connection between the junction block and the kite's pivot point.

[0013] The trimming mechanism may be designed to change both the length of the first tension cord between the branching block and the first pivot point and the length of the second tension cord between the branching block and the second pivot point. If the first pivot point and the second pivot point are arranged on two sides of the pitch axis, a pitching movement can be induced by lengthening the first tension cord and shortening the second tension cord, or vice versa. There may be a line extending between the branching block and a third pivot point of the kite. The first pivot point, the second pivot point, and the third pivot point may form a set of pivot points. Multiple pivot points form a set if they are arranged in a plane that is parallel to a plane spanned by the instantaneous flight direction and the local pulling direction.The articulation points of a set of articulation points can be controlled in a coordinated manner with the trimming device to trigger the pitching movement of the kite. The first and second tension cords can be mechanically coupled to each other via the trimming mechanism.

[0014] In one embodiment, a set of articulation points comprises a first articulation point and a second articulation point, the first articulation point being connected to the branching block via a first tension cord, the second articulation point being connected to the branching block via a second tension cord, the first articulation point and the second articulation point being arranged on one side of the pitch axis, and the second articulation point being at a greater distance from the pitch axis than the first articulation point. The trimming device can be configured such that the first tension cord and the second tension cord are actuated in a coordinated manner, the actuating travel of the first tension cord being smaller than the actuating travel of the second tension cord. In this way, a pitching movement of the kite can be triggered.

[0015] The kite system can be designed such that a set of articulation points comprises one or more articulation points arranged on one side of the pitch axis and one or more articulation points arranged on the other side of the pitch axis. In one embodiment, at least three articulation points are arranged on one side of the pitch axis. The pitch axis can be arranged adjacent to the pressure point of the kite. In particular, the distance, viewed in the longitudinal direction of the kite, between the pressure point of the kite and the pitch axis can be less than 20%, preferably less than 10%, more preferably less than 5% of the distance between the leading edge of the kite and the trailing edge of the kite in the relevant section of the kite. If the pitch axis is arranged close to the pressure point, only a small force is required to actuate the trim mechanism.This is particularly advantageous if the energy required to operate the trim mechanism is provided from the nacelle .

[0016] The invention also encompasses embodiments in which all tension cords are attached in front of the pitch axis or behind the pitch axis. In these embodiments, a greater force is required to actuate the trim mechanism.

[0017] The coordinated control of the articulation points of a set of articulation points with the trimming mechanism can be such that the geometric shape of the kite is maintained within the longitudinal plane of the kite. The longitudinal plane is tensioned by the set of articulation points and the local direction of pull. This can be achieved if the actuating path over which the articulation points are moved during the trimming process is essentially proportional to the distance that the respective articulation point has from the pitch axis. It is also possible that the coordinated control of the articulation points of a set of articulation points with the trimming mechanism is such that the geometric shape of the kite within the set of articulation points is changed by the trimming process. This can be achieved if there is a significant deviation from the proportional relationship between the articulation points of the set of articulation points.For example, the trimming process can give the kite a more curved shape. This has the advantage that the kite develops a high lift force despite a lower flight speed. It is also possible to give the kite a less curved shape so that flight resistance is reduced and a higher flight speed becomes possible. When the kite pitches, the position of the kite changes relative to the position of the gondola. If the movement is considered within the reference system of the kite, i.e. a coordinate system within which the position of the kite remains unchanged, the movement can be described as a pivoting movement of the gondola relative to the kite. The adjustment range of the trimming mechanism can be so large that the pivoting movement extends over an angle of at least 20°, preferably an angle of at least 30°, more preferably an angle of at least 45°.The center of the swivel movement corresponds to the pitch axis.

[0018] The length of a pull cord can be changed by retrieving or releasing an actuating line. The coordinated control of multiple pull cords of a kite system can be achieved by assigning an actuating line to each pull cord, and adjusting the length of the actuating lines separately. For example, each actuating line can be assigned its own actuator.

[0019] A mechanical coupling between a first pull cord and a second pull cord is also possible, so that the length of the first pull cord cannot be changed without the length of the second pull cord being changed at the same time. This can be achieved, for example, by leading an actuating cord of a first pull cord and an actuating cord of a second pull cord to a common actuator, so that when the actuator is actuated, the length of both actuating cords changes. The actuating path of the first actuating cord can be the same as the actuating path of the second actuating cord or can differ from the actuating path of the second actuating cord. The latter can be achieved, for example, by driving the actuating cord via a shaft with a stepped diameter and by guiding the first actuating cord over a different shaft diameter than the second actuating cord.If there are more than two operating lines, the same procedure can be followed.

[0020] The trim mechanism can couple two tension cords belonging to one set of pivot points. It is also possible for tension cords belonging to multiple sets of pivot points to be coupled. In one embodiment, the trim mechanism couples two tension cords located on two sides of a longitudinal center plane of the kite.

[0021] The trim mechanism may comprise a single control line for actuating a first pulley and a second pulley. The control line may be routed over a pulley of the first pulley and a pulley of the second pulley, so that the lengths of the first pulley and the second pulley are changed by retrieving or releasing the control line. A similar procedure may be used for more than two pulleys.

[0022] An operating line of the trim mechanism, which is guided over a pulley, can be equipped with a travel limiter so that the operating line no longer runs over the pulley as soon as the travel limiter hits the pulley. In this way, different effects can be triggered by operating a single operating line depending on the position of the operating line. Equipping an operating line with a travel limiter can be particularly useful when several pulling cords are coupled to one operating line. These can be pulling cords from one set of pivot points or pulling cords from several sets of pivot points. The kite system can comprise a first set of pivot points and a second set of pivot points. If there are two or more sets of pivot points, each set can have the features described in connection with the first set of pivot points.The sets of articulation points can each be arranged parallel to the direction of flight.

[0023] The kite system may comprise two or more sets of articulation points arranged on a first side of the longitudinal center plane of the kite. The kite system may comprise two or more sets of articulation points arranged on a second side of the longitudinal center plane of the kite. All tension cords extending to the first branching block may be arranged on the first side of the longitudinal center plane. All tension cords extending to the second branching block may be arranged on the second side of the longitudinal center plane.

[0024] The trim mechanism can be configured such that several sets of articulation points are coupled so that the pitching movement can be initiated with a single actuation. In particular, the coupling can include sets of articulation points arranged on two sides of the longitudinal center plane of the kite.

[0025] The invention also relates to a device comprising a force absorption point on the ground and in which a tensile force transmitted by the kite system according to the invention via the traction cable acts on the force absorption point. The device can be designed to generate electrical energy. The kite system can be connected to a power machine via the traction cable, so that in a first operating state the power machine acts as a generator driven by the traction cable, and in a second operating state the power machine acts as a motor with which the traction cable is retrieved.

[0026] It is also possible for the kite system to be connected to a force absorption point of a ship, so that the kite system can generate a propulsion force for the ship. A force absorption point of a ship is a force absorption point on Earth within the meaning of the invention.

[0027] The invention also relates to a method for operating a kite system in which a kite is connected to a gondola via a line tree, in which the line tree comprises a branching block, the branching block being connected to the gondola via a control cable, the line tree comprising a first tension cord which extends between the branching block and a first articulation point of the kite, the line tree comprising a second tension cord which extends between the branching block and a second articulation point of the kite, the length of the control cable between the gondola and the branching block being changed by means of a control mechanism and the length of the first tension cord between the branching block and the first articulation point being changed by means of a trimming mechanism.

[0028] The method may include a phase in which the kite system is retrieved using a tow rope. The retrieval may be performed at a speed between 8 m / s and 20 m / s, preferably between 10 m / s and 15 m / s. The tow rope may be retrieved while the kite is positioned within the wind window.

[0029] The disclosure includes further developments of the method with features described in connection with the kite system according to the invention. The disclosure includes further developments of the kite system described in connection with the method according to the invention.

[0030] The invention is described below by way of example with reference to the accompanying drawings using advantageous embodiments. They show:

[0031] Fig. 1: a schematic representation of a device according to the invention;

[0032] Fig. 2: a schematic representation of an operating state of the device from Fig. 1;

[0033] Fig. 3: a kite system according to the invention;

[0034] Fig. 4: a schematic representation of a kite system according to the invention with control mechanism and trim mechanism;

[0035] Fig. 5: a detail of a kite system according to the invention in a schematic representation;

[0036] Fig. 6, 7: the view according to Fig. 5 in an alternative embodiment of the invention;

[0037] Fig. 8: an aspect of a kite system according to the invention in a schematic representation;

[0038] Fig. 9: a detail of a kite system according to the invention;

[0039] Fig. 10: an alternative embodiment of a device according to the invention.

[0040] A device shown in Fig. 1 is designed to generate electrical energy using a kite system 23 according to the invention. The kite system 23 comprises a kite 14, which is connected to a gondola 25 via a line boom 24. The gondola 25 is connected to a traction cable winch 16 via a traction cable 15. The point on the traction cable winch 16 on which the traction cable 15 coming from the gondola 25 rests forms a force absorption point 44 on the earth.

[0041] Coupled to the traction cable winch 16 is an electric power machine 17 which operates as a generator in a first operating state and as a motor in a second operating state. The power machine is connected to a public transmission network 19 via an electrical power train 18 which comprises a converter and a transformer, so that either electrical energy generated by the power machine 17 can be fed into the transmission network 19 or the power machine 17 can be operated as a motor with electrical energy taken from the transmission network 19. The device comprises a control unit 20 which is designed to control the interaction of the components of the device.

[0042] The control unit 20 comprises an antenna 21, allowing control signals to be exchanged with the gondola 25 via a radio link 22. In particular, the control unit 20 sends control signals to the gondola 25 to control the flight direction of the kite 14. Using the control signals, the length of the control lines of the line boom 24 is changed, thereby influencing the flight direction of the kite 14.

[0043] In the embodiment according to Fig. 2, the kite 14 is guided along a horizontal figure eight oriented substantially transversely to the wind direction W. The horizontal figure eight lies completely within a wind window 29, in which the wind W acts on the kite 14 with high force. As the kite 14 follows the direction of flight, a tensile force is exerted on the towing cable 15, with which force the power machine 17 is driven via the towing cable winch 16. With the power machine 17 operated as a generator in this operating state, the mechanical energy is converted into electrical energy and fed into the public transmission grid 19 via the power train 18. It is also possible to store part of the generated energy in electrical form in an energy storage device in the power train 18. In this way, electrical energy can be generated until the length of the traction cable 15 is exhausted and the traction cable 15 is completely paid out by the traction cable winch 16.The traction cable 15 is then retrieved using the power machine 17 operated as a motor before electrical energy can be generated again.

[0044] For retrieval, the kite 14 is currently guided to a position at the edge of the wind window 29, resulting in a loss of time in each cycle. The invention opens up the possibility of retrieving the kite 14 in the center of the wind window 29 with significantly reduced energy and time expenditure.

[0045] 3, the line boom 24 of the kite system 23 according to the invention comprises a plurality of lines 30 via which tensile forces are transmitted between the kite 14 and the gondola 25. Each line 30 extends to a pivot point 31 on the underside of the kite 14. The pivot points 31 are evenly distributed over the surface of the kite 14 and arranged symmetrically to a longitudinal center plane 34 of the kite 14, which is spanned by the current flight direction 33 and the direction 32 of the towing cable 15. The lines 30 attached to the kite 14 in an outer region of the kite 14, i.e. at a large distance from the longitudinal center plane 34, converge on one side of the longitudinal center plane 34 in a first branching block 27 and on the other side of the longitudinal center plane 34 in a second branching block 28. A first control cable 35 extends between the first branching block 27 and the gondola 25.A second control cable 36 extends between the second branching block 28 and the gondola 25.

[0046] 4, in which the kite 14 is only schematically indicated by three longitudinal sections, the first control cable 35 and the second control cable 36 are coupled to one another via a first drive roller 38. The control cables 35, 36, together with the first drive roller 38 and a drive motor belonging to the first drive roller 38, form a control mechanism 39 of the kite system. If the control mechanism 39 is actuated, one of the control cables 35, 36 is shortened, while the other is lengthened accordingly. This leads to a rolling movement of the kite 14 about a roll axis located in the longitudinal center plane 34, which is aligned parallel to the current flight direction 33. The new aerodynamic state of the kite 14 causes the kite 14 to fly a curve and rotate around the towing cable 15.

[0047] The kite system further comprises a trim mechanism 40, in which a trim cable 41 is guided over a second drive pulley 42. A first end of the trim cable 41 is coupled to two rear operating lines 45, a second end of the trim cable 41 is coupled to two front operating lines 46. Each operating line 45, 46 is connected with one end to one of the branching blocks 27, 28 and with its other end to the trim cable 41. In the exemplary illustration in Fig. 4, there are a total of four paths along which the operating lines 45, 46 extend between the trim cable 41 and the branching blocks 27, 28. Each of these paths leads over a pulley 47, which is connected via a line 30 to a pivot point 31 of the kite.

[0048] A tensile force acting between the respective pivot point 31 and the associated branching block 27, 28 is transmitted via a tension cord extending from the pivot point 31 via a roller 47 and a portion of the associated actuating line 45, 46 to the associated branching block 27, 28. In the embodiment in Fig. 4, there is a front tension cord 48 and a rear tension cord 49 on each side.

[0049] When the trim mechanism 40 is actuated, one of the tension cords 48, 49 is shortened and the other tension cord 48, 49 is lengthened. The pivot point 31 located between the tension cords 48, 49 is at a fixed distance from the associated branch block 27, 28, so that the lengthening and shortening of the tension cords 48, 49 leads to a pitching movement of the kite 14.

[0050] The middle of the three longitudinal sections of the kite 14 shown in Fig. 4 is directly coupled to the trim cable 41, so that the central region of the kite 14 also performs a pitching movement. The pitch axis 51 in the central region of the kite 14 is aligned perpendicular to the direction 32 of the towing cable 15 and perpendicular to the current flight direction 33. Due to the curved shape of the kite 14, the local pitch axes 51 differ in their direction. In the regions of the kite 14 that are at a distance from the longitudinal center plane 34, the local pitch axis 51 is aligned at right angles to the flight direction 33 and to the local pulling direction 52, 53, as it results from the pulling strands 48, 49.

[0051] The pitching movement changes the angle of attack of the kite 14. By shortening the front pull cord 48 and lengthening the rear pull cord 49, the angle of attack can be changed so that the kite 14 only exerts a low tensile force on the pull rope 15. The kite 14 can be retrieved using the pull rope winch 16 within the wind window 29 without the pull rope winch 16 having to apply a high force. This enables the kite 14 to be retrieved quickly at a speed of, for example, more than 10 m / s. The retrieve leads to an additional relative movement between the kite 14 and the air, which stabilizes the flight state of the kite 14.

[0052] To make this possible, the trim mechanism 40 has a large adjustment range 54. Two extreme positions of the trim mechanism 40 are shown in Fig. 8 using a coordinate system within which the kite 14 has a fixed position. In the exemplary embodiment, the adjustment range 54 extends over more than 40°.

[0053] Despite the changed trim state, the kite 14 can still be controlled with the control mechanism 39. This is because all tension cords 48, 49 involved in a local pitching movement of the kite 14 are routed to the same branching block 27, 28. If the control mechanism 39 is actuated, this causes a rolling movement of the kite 14, regardless of the state to which the trim mechanism 40 is set.

[0054] The principle underlying the trimming mechanism 39 in Fig. 4 is explained again in Fig. 5 using a simplified schematic diagram. The section shown is the longitudinal section through the kite 14 on the left in Fig. 4, which is connected to the first branching block 27. By actuating the trimming mechanism 40, the front tension cord 48 can be shortened and the rear tension cord 49 can be lengthened. Since the middle pivot point 31 of the three pivot points 31, 61, 62 is connected to the first branching block 27 via a line 55 of fixed length, this results in a pitching movement whose local pitch axis 51 coincides with the middle pivot point 31. The pivot points 31, 61, 62 arranged in a common longitudinal plane of the kite 14 form a set 56 of pivot points. In the exemplary embodiment in Fig. 5 there are three articulation points 31 which form the set 56 of articulation points 31. As shown in Fig.3 shows, the kite 14 can be connected to the branching blocks 27, 28 or to the gondola 25 via a larger number of sets 56 of articulation points arranged parallel to one another.

[0055] In Fig. 5, the central pivot point 31 is located near the pressure point 63 of the kite, so that no great force is required to change the angle of attack of the kite 14. Furthermore, the central pivot point 31 is arranged centrally between the front pivot point 61 and the rear pivot point 62. With this configuration of the set 56 pivot points 31, 61, 62, the pitching movement about the local pitch axis 51 can be fully controlled without changing the local geometric shape of the kite 14.

[0056] In the alternative embodiment in Fig. 6, the set 56 of pivot points 31 is designed such that the pitching movement about the local pitch axis 51 simultaneously causes a change in the local geometric shape of the kite 14. The middle pivot point is a smaller distance from the rear pivot point than from the front pivot point. Given the same actuation paths of the front pull cord 48 and the rear pull cord 49, shortening the front pull cord 48 and lengthening the rear pull cord 49 leads to an increased camber of the kite 14. An increased camber may be desired, for example, so that the kite 14 maintains a stable flight condition despite low flight speed.

[0057] In the exemplary embodiment in Fig. 7, the front pivot point 31 is connected to the first branching block 27 via a line 55 of fixed length. The two rear pivot points 61, 62 are coupled to the first branching block 27 via the trim cable 41 in the manner of a pulley system. If, starting from the state shown in Fig. 7, the trim cable 41 is released, the rear pivot point 62 moves upwards faster than the middle pivot point 61. This results in a pitching movement whose local pitch axis 51 lies in front of the two upwardly moved pivot points 61, 62. The local geometric shape of the kite 14 is maintained during the pitching movement. In this embodiment, the trim cable 41 forms the tension cord for the two moving articulation points 31 between the kite 14 and the first branching block 27, the length of which can be changed.

[0058] The kite system in Fig. 4 is designed so that the front operating line 45 and the rear operating line 46 have identical operating paths. If this is not desired, a drive roller 42 having a stepped diameter can be used for the trim mechanism 40. Fig. 9 shows an exemplary embodiment of such a stepped drive roller 42, over which a third operating line 57 is guided in addition to the front operating line 45 and the rear operating line 46. Due to the three different diameters of the drive roller 42, the operating paths of the three operating lines differ from one another.

[0059] In Fig. 10 an alternative embodiment of the invention is shown, in which the kite system 23 according to the invention is used to generate a propulsion force for a ship 43.

Claims

Patent claims 1. Kite system with a kite (14), with a gondola (25) and with a line tree (24), wherein the kite (14) is connected to the gondola (25) via the line tree (24), wherein the line tree (24) comprises a branching block (27, 28), wherein the branching block (27, 28) is connected to the gondola (25) via a control cable (35, 36), wherein the line tree (24) comprises a first tension cord (48) which extends between the branching block (27, 28) and a first articulation point (61) of the kite (14), wherein the line tree (24) comprises a second tension cord (49) which extends between the branching block (27, 28) and a second articulation point (62) of the kite (14), with a control mechanism (39) to control the length of the control cable (35, 36) between the nacelle (25) and the branching block (27, 28), and with a trimming mechanism (40) to change the length of the first tension cord (48) between the branching block (27, 28) and the first articulation point (61).

2. Kite system according to claim 1, comprising a first control cable (35) and a second control cable (36), wherein the first control cable (35) acts on a different section of the kite (14) than the second control cable (36).

3. Kite system according to claim 1 or 2, wherein the control mechanism (39) is designed to trigger a rolling movement of the kite (14).

4. Kite system according to one of claims 1 to 3, wherein the trim mechanism (40) is designed to trigger a pitching movement of the kite (14) about a pitch axis (51).

5. Kite system according to claim 4, wherein the pitch axis (51) has a fixed distance from the branching block (27, 28).

6. Kite system according to claim 4 or 5, wherein the pitch axis (51) is arranged adjacent to the pressure point (63) of the kite (14).

7. Kite system according to one of claims 1 to 6, wherein the trimming mechanism (40) is designed to change both the length of the first tension cord (48) between the branching block (27, 28) and the first pivot point (61) and the length of the second tension cord (49) between the branching block (27, 28) and the second pivot point (62).

8. Kite system according to claim 7, wherein the first tension cord (48) and the second tension cord (49) are mechanically coupled to one another via the trim mechanism (40).

9. Kite system according to one of claims 1 to 8, wherein the trimming mechanism (40) is designed such that the kite (14) is given a more curved shape by the trimming process.

10. Kite system according to one of claims 1 to 9, wherein the trimming mechanism (40) covers an adjustment range of at least 20°, preferably of at least 30°, more preferably of at least 45°, relative to the coordinate system of the kite (14).

11. Kite system according to one of claims 1 to 10, wherein two tension cords (48, 49) are coupled to one another by the trim mechanism (40), which are arranged on two sides of a longitudinal center plane (34) of the kite (14).

12. Device comprising a kite system (23) and a force absorption point (44) on the ground, wherein the kite system (23) is designed according to one of claims 1 to 11 and wherein the tensile force transmitted from the kite system (23) via the traction cable (15) acts on the force absorption point (44).

13. Device according to claim 12, wherein the kite system (23) is connected to a power machine (16) via the traction cable (15), so that in a first operating state the power machine (16) acts as a generator which is driven by the traction cable (15), and that in a second operating state the power machine (16) acts as a motor with which the traction cable (15) is retrieved.

14. Method for operating a kite system in which a kite (14) is connected to a gondola (25) via a line tree (24), in which the line tree (24) comprises a branching block (27, 28), wherein the branching block (27, 28) is connected to the gondola (25) via a control cable (35, 36), wherein the line tree (24) comprises a first tension cord (48) which is located between the branching block (27, 28) and a first articulation point (61) of the kite (14), wherein the line tree (24) comprises a second tension cord (49) extending between the branching block (27, 28) and a second articulation point (62) of the kite (14), wherein the length of the control cable (35, 36) between the nacelle (25) and the branching block (27, 28) is changed by a control mechanism (39), and wherein the length of the first tension cable (48) between the branching block (27, 28) and the first articulation point (61) is changed by a trimming mechanism (40).

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