Variable electromagnetic drive train - dynamic TSR (variable swept area VAWT) with integrated control mechanism

Abstract

This invention introduces an advanced Variable Electromagnetic Drive Train specifically designed to optimize the Angular speed of wind turbines, particularly vertical axis wind turbines (VAWTs ), under different wind conditions. The system achieves efficient RDM optimization through its electromagnetic drive train, enabling the generator to maintain optimal performance independently of the turbine's rotational speed. Torque optimization is accomplished via one of these methods. First, the drive train dynamically adjusts the Tip-Speed Ratio (TSR), allowing the turbine to adapt to varying wind intensities by adjusting the swept area-arms. Second, an additional stator layer within the electromagnetic drive train provides precise control over torque. This design within the electromagnetic drive train enables fine-tuned adjustments to both speed and torque, maximizing energy capture and maintaining consistent power output. By decoupling the generator's operating parameters from fluctuating wind speeds, this system enhances efficiency and reliability across a wide range of environmental conditions. This innovative approach is also applicable to horizontal axis wind turbines (HAWTs ) and other mechanical systems where precise control over RPM and torque is essential. The variable electromagnetic drive train technology thus provides a flexible, adaptable solution for sustainable energy generation and mechanical applications requiring robust control over dynamic loads.

Description

[0001] P143309PC00

[0002] Variable Electromagnetic Drive Train - Dynamic TSR (Variable Swept Area VAWT) With Integrated Control Mechanism

[0003] BACKGROUND

[0004] This invention pertains to power generation systems, specifically a variable electromagnetic drive train designed to adjust angular speed and dynamically adjust the Tip-Speed Ratio (TSR) in vertical axis wind turbines (VAWT) with a variable swept area and an integrated control mechanism.

[0005] In conventional wind turbines, both vertical-axis (VAWT) and horizontal-axis (HAWT) systems face intrinsic limitations due to their static configurations and mechanical constraints, leading to suboptimal performance across variable wind conditions. In such systems, energy capture relies on rotor blades that follow a fixed tip-speed ratio (TSR) and are mounted to a stationary generator shaft. However, these turbines exhibit notable inefficiencies due to limitations in adaptability and design.

[0006] Fixed Tip-Speed Ratio (TSR): Conventional wind turbines are engineered with a predetermined TSR, which is the ratio between the blade tip speed and wind speed. This fixed TSR is optimized for specific wind speeds, yet it cannot dynamically respond to fluctuations in wind velocity. As a result, turbine efficiency drops significantly outside the design-optimized conditions, particularly in irregular wind regimes. The inability to modulate TSR constrains the turbine' s aerodynamic efficiency, as it cannot continually align with the optimal TSR range to maximize power coefficient (Cp) under varying conditions. Static Swept Area: Traditional turbines are limited by a fixed swept area, which is the circular section of wind intercepted by the rotor. A constant swept area restricts the turbine' s capacity to modulate energy capture as wind conditions shift. In scenarios of gusty or turbulent wind, the fixed area results in either excess or inadequate energy capture relative to the optimal energy potential of the moment. This static swept area design not only leads to inefficiency but also subjects the turbine components to variable mechanical stresses, potentially shortening operational life and increasing fatigue loading.

[0007] Mechanical Transmission Systems: Conventional turbines typically employ mechanical transmission systems to convert the rotor ' s kinetic energy into electrical energy at a set RPM. These systems often utilize gearboxes to increase rotational speed and adjust torque, yet the use of fixed gear ratios introduces significant inefficiency and wear in variable wind conditions. The dependence on mechanical gearing, combined with high rotational speeds, leads to substantial energy loss through friction and necessitates rigorous maintenance regimes. Additionally, the fixed mechanical systems lack real-time adaptability to changing aerodynamic loads, limiting dynamic response and potentially diminishing system reliability over extended operational periods.

[0008] Limited Adaptability to Variable Wind Conditions: The design rigidity of conventional wind turbines restricts their ability to dynamically adjust to a broad range of wind speeds and directions. These turbines are optimized for average wind conditions at a given location but lack the flexibility to efficiently harness energy across a spectrum of velocities and turbulence levels. As a result, in nonideal wind conditions, traditional turbines frequently operate below optimal efficiency levels. Moreover, this limitation increases stress on structural components, which are continually exposed to non-uniform wind forces, thus heightening the risk of fatigue-induced failures. Consequently, these limitations in conventional wind turbines manifest as restricted operational efficiency, heightened mechanical wear, and frequent maintenance requirements, undermining both energy output potential and long-term system durability.

[0009] SUMMARY OF THE INVENTION

[0010] The rotor of conventional wind turbines is connected to a generator through either a direct drive (DD) configuration or a gearbox, as in a doubly-fed induction generator (DFIG) or permanent magnet generator (PMSG) system. The generator operates most efficiently within a specific range of rotational speeds (RPM) and torque, defined by its RPM vs. Torque curve. However, a significant drawback of conventional designs is that the rotor speed, influenced by wind speed, is directly coupled to the generator shaft' s RPM in DD systems or indirectly through a fixed-ratio gearbox in DFIG systems. This coupling imposes substantial limitations on the turbine ' s ability to operate efficiently at variable wind speeds, particularly under sub- optimal or turbulent wind conditions.

[0011] Wind turbines typically have a high rated speed to achieve optimal power output under ideal wind conditions (around 11–15 m / s for standard designs). However, in real-world conditions, wind speeds often fall below this rated speed, especially in inland, low altitude or low-wind areas. When the wind speed is low, the rotor' s RPM is correspondingly low, which results in insufficient rotational speed at the generator shaft to reach its optimal RPM range. This misalignment forces the generator to operate outside its peak efficiency, leading to increased inefficiencies in energy conversion.

[0012] Additionally, in fluctuating or turbulent wind conditions, rapid changes in wind speed result in constant adjustments to the rotor speed. In a conventional DFIG system, the gearbox ratio is fixed, which further restricts the generator ' s ability to adapt to the variable torque and speed requirements needed to maintain an optimal energy conversion rate. Consequently, the generator spends most of its operational time in a sub-optimal RPM range, where power losses are high, and the energy yield is low relative to the available wind resource.

[0013] According to a first aspect, the invention provides a system for optimizing angular speed and torque, configured for generating electrical power, the system comprising:

[0014] a wind turbine having a turbine output shaft operatively connected to the input shaft of an electromagnetic transmission device;

[0015] an electromagnetic transmission device for transmission of a rotational movement operatively connected to the turbine output shaft and configured for transmitting the rotational input to an electrical power generator; and an electrical power generator having a generator input shaft operatively connected to the electromagnetic transmission device, and an output for outputting electrical power,

[0016] wherein the electromagnetic transmission device, comprises:

[0017] an input rotor with an input shaft operatively connected thereto that is operatively connected to the turbine output shaft;

[0018] an output rotor arranged concentrically with the input rotor, and with an output shaft operatively connected thereto that is operatively connected to the generator input shaft;

[0019] wherein one of the input rotor and the output rotor is provided with a plurality of electromagnets arranged thereon, and

[0020] wherein the system comprises a controller operatively connected to the plurality of electromagnets and configured for maintaining the rotational speed of the generator input shaft within a predetermined range by injecting and / or retracting electrical power into and / or from the plurality of electromagnets, and

[0021] a torque adjustment module for adjusting the torque applied to the generator input shaft, wherein the torque adjustment module is operatively connected to the controller and the controller is configured for maintaining the torque applied within a predetermined range.

[0022] According to the invention, a rotor of a vertical axis wind turbine may be connected to the input shaft of the electromagnetic transmission device, and the generator of the vertical axis wind turbine may be connected to the output shaft of the electromagnetic transmission device. Therefore, during use, rotational movement of the rotor results in rotational movement of the input shaft and thereby of the input rotor. The Rounds Per Minute (RPM) of the input rotor corresponds to the RPM of the rotor of the wind turbine.

[0023] Furthermore, the controller is enabled to inject and / or retract electrical power into and / or from the plurality of electromagnets. By injecting or retracing electrical energy into or from, respectively, the plurality of electromagnets, the electromagnetic field strength generated by the plurality of electromagnets is increased or decreased, respectively. Increasing or decreasing the electromagnetic field strength effectuates the RPM of the output rotor to increase or to decrease, respectively. Simultaneously, the torque adjustment module maintains the torque within the predetermined range. This is advantageous as the torque and the RPM are kept within a predetermined range, regardless of the input at the input shaft of the electromagnetic transmission device, so that the electrical power generator may operate within the optimal range all the time. This is advantageous as this results in the generator generating electricity more efficiently, which results in a constant power output independent from wind speeds acting on the turbine.

[0024] The invention aims to address the technical limitations mentioned above by decoupling the generator' s RPM from the rotor' s RPM. By introducing a variable-speed mechanism or adaptive drive train, the generator could operate independently of the rotor' s fluctuating speed, maintaining its optimal RPM and torque range across a wider range of wind speeds. This would reduce dependency on high wind speeds to achieve rated performance, allowing for more efficient energy conversion even under low, high, or turbulent wind conditions, thereby increasing the turbine' s overall capacity factor and improving its economic viability.

[0025] A further advantage of the invention may be that the system for optimizing angular speed and torque, configured for generating electrical power simplifies the connection of a generator, for example, to a power grid, as the electrical power generator has a constant power output, independent from the winds speeds.

[0026] In an embodiment, the controller further is configured for determining an output parameter of the electrical power put out at the output of the electrical power generator, and for comparing the output parameter with a predetermined threshold in order to determine whether the determined output parameter is above or below the predetermined threshold. In an embodiment thereof, the controller is configured to inject electrical power into the plurality of electromagnets and / or to control the torque adjustment module to increase the torque applied, when it is determined that the determined output parameter is below the predetermined threshold. In an even further embodiment thereof, the controller is configured to extract electrical power from the plurality of electromagnets and / or to control the torque adjustment module to decrease the torque applied, when it is determined that the determined output parameter is above the predetermined threshold. According to this embodiment, the controller may keep fluctuations in the rotational speed of and / or the torque at the output rotor to a minimum, thereby providing a stable and reliable output of the generator. In an embodiment, the output parameter is selected from the group comprising frequency of the electrical energy at the output of the electrical power generator

[0027] In an embodiment, the controller is configured to control the torque adjustment module firstly, whereafter electrical power is injected into or extracted from the plurality of electromagnets, preferably wherein the torque adjustment module is further configured for adjusting the RPM of the input rotor.

[0028] In an embodiment, the system for optimizing angular speed and torque, configured for generating electrical power comprises an energy storage and an electrical power convertor, wherein the energy storage is electrically connected to the electrical power convertor, and the electrical power convertor is electrically connected to the plurality of electromagnets, or

[0029] comprises an electrical power convertor and a grid connector operatively connected to the electrical power convertor and configured for being connected to an energy grid. In an embodiment thereof, the controller is configured to operate the electrical power convertor to extract electrical power from the energy storage or from the energy grid, when it is determined that the determined output parameter is below the predetermined threshold. In an even further embodiment thereof, the controller is configured to operate the electrical power convertor to extract electrical power from the electromagnetic transmission device and / or torque adjustment module, and to inject the extracted electrical power into the energy storage or into the energy grid, when it is determined that the determined output parameter is above the predetermined threshold. During use, for example when the system for optimizing angular speed and torque, configured for generating electrical power comprises an energy storage and an electrical power convertor, when the input speed of the input rotor exceeds a predetermined threshold, the converter intervenes to store the surplus energy in the energy storage. This capability ensures that excess energy is not wasted but rather conserved for future use. Vice versa, when the input speed of the input rotor falls below the predetermined threshold, the converter compensates by drawing energy from the energy storage. This energy management strategy ensures that the output rotor at a constant speed, thereby providing a stable and reliable output from the generator.

[0030] In an embodiment, the electromagnetic transmission device comprises a cylindrical housing defining a transmission space and having a first closed end and a second closed end, opposite to each other, wherein the input rotor and the output rotor are arranged within the transmission space. In an embodiment thereof, the other one of the input rotor and the output rotor is provided with a number of permanent magnets arranged thereon.

[0031] In an embodiment, the torque adjustment module comprises a stator arranged within the electromagnetic transmission device and comprising a further plurality of electromagnets, and

[0032] wherein the controller is operatively connected to the further plurality of electromagnets of the outer stator and is configured for controlling the torque of the output shaft by injecting and / or retracting electrical power into and / or from the further plurality of electromagnets. The inventors have surprisingly found that providing the stator results advantageously in consistent interaction with the moving magnetic fields, and results in a relatively simple overall control strategy.

[0033] In an embodiment, the output rotor is arranged within the input rotor, and wherein the output rotor comprises the plurality of electromagnets and the input rotor comprises the number of magnets. In an embodiment thereof, the input rotor comprises a input cylindrical wall arranged concentrically about the output rotor, wherein the number of magnets is provided at the inner circumference of the input cylindrical wall and are distributed evenly over the inner circumference, when seen in circumferential direction. Preferably, each of the number of magnets has a magnetic north and south pole, and wherein the magnets are arranged in such manner that the north and south poles of the magnets are alternating in the circumferential direction. In another embodiment thereof, the number of magnets is also provided at the outer circumference of the input cylindrical wall and are distributed evenly over the outer circumference, when seen in circumferential direction.

[0034] In an embodiment, the input rotor is arranged within the output rotor, and wherein the input rotor comprises the number of magnets, and the output rotor comprises the plurality of electromagnets. In an embodiment thereof, the number of magnets is arranged at the outer circumference of the input rotor, and such that the north and south poles of the magnets are alternating in the circumferential direction thereof, and

[0035] wherein the output rotor comprises an output cylindrical wall and the plurality of electromagnets is arranged at the inner circumference of the output cylindrical wall. According to an embodiment, the wind turbine is a vertical axis wind turbine having a vertical axis connected to the turbine output shaft, retractable turbine blade (s) connected to the vertical axis, and a drive operatively connected to the retractable turbine blade (s), wherein the retractable turbine blade (s) is (are) configured to be moved by means of the drive between an extended position, in which the retractable turbine blade (s) defines (define) a first swept area, and a retracted position, in which the retractable turbine blade (s) defines (define) a second swept area that is smaller than the first swept area,

[0036] wherein the torque adjustment module is defined by the retractable turbine blades, and

[0037] wherein the controller is operatively connected to the drive of the vertical axis wind turbine to control the position of the retractable turbine blades, so that the torque may be adjusted based on the turbine' s TSR ratio. In an embodiment thereof, the controller is configured to operate the drive of the vertical axis wind turbine to move the retractable turbine blade (s) towards the extended position, in order to increase the torque applied. More preferably, the controller is configured to operate the drive of the vertical axis wind turbine to move the retractable turbine blade (s) towards the retracted position, in order to decrease the torque applied. When the retractable turbine blade (s) are in the extended position, the turbine blade (s) extends (extend) over a larger area in comparison to when the retractable turbine blade (s) is (are) in the retracted position. When the force applied to the vertical axis wind turbine by the wind increases or decreases, the torque will also increase or decrease, respectively, when the turbine blades remain in the same position. When it is determined that the torque is above or below the predetermined torque threshold, the turbine blades may be moved between the extended and retracted position to decrease or increase, respectively, the area covered by the turbine blades. For a constant rotational speed of the output rotor of the electromagnetic transmission device, if the torque at the input rotor increases, the rotational speed of the input rotor must decrease, in fixed wind speed situation. This may result in a lower rotational speed of the output shaft. As the electromagnetic transmission device is configured for maintaining the rotational speed of the output shaft within a predetermined range, the electromagnetic transmission device will increase the rotational speed of the output rotor by injecting electrical energy, or vice versa. The system for optimizing angular speed and torque, configured for generating electrical power according to this embodiment applies a variable tip-speed ration (TSR) for controlling the wind turbine. This is advantageous, as it enables swept area to be adjusted to adjust amount of input power from wind and adjust Torque / RPM by variable TSR rate and the controller of the electromagnetic transmission device adjusts the electrical parameters thereof so that the rotational speed of the output shaft is maintained within the predetermined range, which results in that the connected generator may provide a consistent power output.

[0038] This embodiment pertains to a system for optimizing angular speed and torque, specifically a variable electromagnetic drivetrain designed to adjust angular speed and dynamically control the Tip-Speed Ratio (TSR) in vertical-axis wind turbines (VAWTs) with a variable swept area and an integrated control mechanism. The system optimizes performance under varying wind conditions by dynamically adjusting the turbine ' s swept area and precisely controlling the TSR to achieve maximum efficiency. Moreover, this variable electromagnetic drivetrain technology is not limited to VAWTs but is also applicable to horizontal-axis wind turbines (HAWTs), enhancing efficiency through dynamic adjustments and adaptability to different wind conditions.

[0039] In conventional wind turbines, wind energy is used to rotate blades, transferring this motion to a rotor connected to a vertically or horizontally mounted generator with or without gearbox that produces electricity. However, this innovative system according to this embodiment, with its variable electromagnetic drive train and adjustable swept area, enables dynamic adjustments according to wind conditions. Rather than a static design, the system can operate optimally in diverse conditions.

[0040] Furthermore, the variable electromagnetic drivetrain can also be utilized independently, making it suitable for various applications beyond wind energy, where precise control over speed and torque is required. This versatility expands its potential across multiple industries, providing a flexible and efficient solution for power generation and mechanical systems in need of adaptable drive train technology.

[0041] A further advantage of being able to move the turbine blades between the extended position and the retracted position may be that energy capture is optimized in low wind conditions, and / or that stress on the turbine blades is minimized in high wind conditions.

[0042] In an embodiment, the system for optimizing angular speed and torque, configured for generating electrical power comprises a blade pitch and arms adjusting mechanism operatively connected to the turbine blade (s), and configured for adjusting the pitch and arms of at least one of the turbine blade (s). By adjusting the blade pitch, the turbine can maintain an optimal rotor speed. In high winds, the blades may be pitched to reduce aerodynamic drag, preventing overspeed. In low winds, the blades may be pitched to capture more wind energy, increasing torque and speed.

[0043] According to a second aspect, the invention provides a method for operating a system for optimizing angular speed and torque, configured for generating electrical power according to the first aspect of the invention, the method comprising the steps of:

[0044] controlling the rotational speed of the output shaft by injecting and / or retracting electrical power into and / or from the plurality of electromagnets; and adjusting the torque applied to the output shaft for maintaining the torque applied within a predetermined range.

[0045] The method according to the invention has at least the same technical advantages as described in relation to the first aspect of the invention.

[0046] In an embodiment, the method comprises the step of determining an output parameter of the electrical power put out at the output of the electrical power generator, and of comparing the output parameter with a predetermined threshold in order to determine whether the determined output parameter is above or below the predetermined threshold. In an embodiment thereof, the method comprises the step of injecting electrical power into the plurality of electromagnets and / or of controlling the torque adjustment module to increase the torque applied, when it is determined that the determined output parameter is below the predetermined threshold. In an even further embodiment thereof, the method comprises the step of extracting electrical power from the plurality of electromagnets and / or of controlling the torque adjustment module to decrease the torque applied, when it is determined that the determined output parameter is above the predetermined threshold.

[0047] In an embodiment, wherein the torque adjustment module comprises a stator arranged within the electromagnetic transmission device and comprising a further plurality of electromagnets, and wherein the controller is operatively connected to the further plurality of electromagnets of the outer stator and is configured for controlling the torque of the output shaft by injecting and / or retracting electrical power into and / or from the further plurality of electromagnets, the method comprises the step of controlling the torque applied of the output shaft by injecting and / or retracting electrical power into and / or from the plurality of electromagnets and / or the further plurality of electromagnets.

[0048] In an embodiment, the step of determining an output parameter comprises determining the frequency of the electrical power put out at the output of the electrical power generator.

[0049] According to a third aspect, the invention provides an electromagnetic transmission device for use in a system for optimizing angular speed and torque, configured for generating electrical power according to the first aspect of the invention, or a method according to the second aspect of the invention, and as defined in relation thereto.

[0050] The various aspects and features described and shown in the specification can be applied, individually, wherever possible. These individual aspects, in particular the aspects and features described in the attached dependent claims, can be made subject of divisional patent applications.

[0051] BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The invention will be elucidated on the basis of an exemplary embodiment shown in the attached drawings, in which:

[0053] Figures 1A and 1B show an isometric view of an electromagnetic transmission device of a system for optimizing angular speed and torque, configured for generating electrical power according to an embodiment of the invention, and a schematic overview thereof, respectively;

[0054] Figure 2 shows a cross-section parallel to the longitudinal axis of the electromagnetic transmission device of figure 1A;

[0055] Figure 3 shows a cross-section transverse to the longitudinal axis of the electromagnetic transmission device of figure 1A;

[0056] Figure 4 shows an isometric view of an electromagnetic transmission device of a system for optimizing angular speed and torque, configured for generating electrical power according to another embodiment of the invention;

[0057] Figure 5 shows a cross-section parallel to the longitudinal axis of the electromagnetic transmission device of figure 4;

[0058] Figure 6 shows a cross-section transverse to the longitudinal axis of the electromagnetic transmission device of figure 4; and

[0059] Figure 7 shows an isometric overview of a vertical axis wind turbine of a system for optimizing angular speed and torque, configured for generating electrical power according to an embodiment of the invention. DETAILED DESCRIPTION OF THE INVENTION

[0060] An isometric view of an electromagnetic transmission device 1 of a system for optimizing angular speed and torque, configured for generating electrical power according to an embodiment of the invention is shown in figure 1. The electromagnetic transmission device 1 may be used for transmission of an input rotational movement, for example, generated by rotation of the rotor blades of a wind turbine, in particular a vertical or horizontal wind turbine, to an output rotational movement, for example, to a generator.

[0061] The electromagnetic transmission device 1 has a housing 2, in particular a cylindrical housing 2, in which a transmission space 3 is defined. In the transmission space 3, the input rotational movement is transmitted to the output rotational movement. The cylindrical housing 2 has a cylindrical wall 4 with a first closed end 5 and a second closed end 6, opposite to the first closed end 5 in the longitudinal direction of the cylindrical housing 2. The electromagnetic transmission device 1 includes an input shaft 7 configured for being connected to an input source and for allowing the input rotational movement to be inputted, such as the wind turbine, wherein the input shaft 7 extends from the outside, in a sealed manner, through the first closed end 5 into the transmission space 3. Furthermore, the electromagnetic transmission device 1 comprises an output shaft 8 configured for being connected to an output device, such as a power generator, for allowing the output rotational movement to be outputted, wherein the output shaft 8 extends from the outside, in a sealed manner, through the second closed end 6 into the transmission space 3.

[0062] As shown in figures 2 and 3, within the transmission space 3, the electromagnetic transmission device 1 has an outer stator 10 provided at and fixed to the inner circumference of the cylindrical wall 4. The outer stator 10 has a fixating ring 11 for fixating the outer stator 10 to the inner circumference of the cylindrical wall 4. At the inner circumference of the fixating ring 11, i. e. the side facing towards the center of the transmission space 3, a plurality of electromagnets 12 is arranged. Each of the plurality of electromagnets 12 includes a T-shaped magnetic core 13, of which the bottom side is connected to the inner circumference of the fixating ring 11. Due to the plurality of electromagnets 12 being arranged next to each other, a plurality of outer chambers 14 is defined between the T- shaped magnetic cores 13. Within each of the plurality of outer chambers 14, a solenoid 15 is arranged so that an electromagnetic field may be realized by the plurality of electromagnets 12.

[0063] As best shown in figure 2, outer stator 10 has a height that is smaller than the height of the cylindrical wall 4.

[0064] Although not shown, each of the plurality of electromagnets 12 is operatively connected to a controller configured for controlling operation of the electromagnetic transmission device 1.

[0065] As shown in figures 2 and 3, the electromagnetic transmission device 1 further comprises an input rotor 20, which is arranged concentrically with the outer stator 10. The input rotor 20 has an input cylindrical wall 21 with a diameter that is, preferably slightly, smaller than the inner diameter of the out stator 10. The input cylindrical wall 21 has a third closed end 22, at the side facing towards the first closed end 5 of the housing 2, and a fourth closed end 23, at the side facing towards the second closed end 6 of the housing 2.

[0066] As best shown in figure 2, the input shaft 7 merges into the third closed end 22 of the input rotor 20, in particular at the side of the third closed end 22 facing away from the fourth closed end 23. At the side of the third closed end 22 facing towards the fourth closed end 23, a receiving recess 24 is defined. As best shown in figure 2, the output shaft 8, in a sealed manner, extends through the second closed end 6 of the housing 2 and through the fourth closed end 23 of the input rotor 20, wherein the output shaft 8 extends into the receiving recess 24. Within the receiving recess 24, the respective end of the output shaft 8 is rotatable received within a bearing 25.

[0067] As best shown in figure 3, the input rotor 20 is provided with a number of permanent magnets 26. The permanent magnets 26 are arranged at the inner circumference of the input cylindrical wall 21, i. e. the side facing towards the center of the transmission space 3, and at the outer circumference of the input cylindrical wall 21, i. e. the side facing away from the center of the transmission space 3. When seen in the circumferential direction, the permanents magnets 26 are placed at a distance from each other, and are evenly distributed over the circumference of the input cylindrical wall 21. The permanent magnets 26 have magnetic north and south poles, and are arranged in such manner that the north and south poles of the permanents magnets 26 at both the inner circumference and the outer circumference of the input cylindrical wall 21, are alternating in the circumferential direction thereof.

[0068] During use, rotation of the input shaft 8 results in corresponding rotation of the input rotor 20.

[0069] As shown in figure 2, the electromagnetic transmission device 1 further comprises an output rotor 30, which is arranged concentrically within the input rotor 20. The output rotor 30 comprises a cylindrical ring 31 that, at the inner circumference thereof, is connected to the output shaft 8 by means of multiple connectors 32. Furthermore, the output rotor 30 is provided with a plurality of electromagnets 33 arranged at the outer circumference of the cylindrical ring 31, i. e. the side facing away from the center of the transmission space 3. Each of the plurality of electromagnets 33 includes a T-shaped magnetic core 34, of which the bottom side is connected to the outer circumference of the cylindrical ring 31. Due to the plurality of electromagnets 33 being arranged next to each other, a plurality of inner chambers 35 is defined between the T-shaped magnetic cores 34. Within each of the plurality of inner chambers 35, a solenoid 36 is arranged so that, an electromagnetic field may be realized by the plurality of electromagnets 33.

[0070] As schematically indicated in figure 1B, the electromagnetic transmission device 1 further comprises a controller 40 that is operatively connected to the outer stator 10 and the output rotor 30, in particular the plurality of electromagnets 12, 33 thereof. Additionally, an energy storage 41, such as a battery, is provided, which energy storage 41 is electrically connected to the output rotor 30 via a first power convertor 42, and to the outer stator 10 via a second power convertor 43.

[0071] During use of the electromagnetic transmission device 1, the controller 40 is configured to control the rotational speed of the output shaft 8 and the torque at the output shaft 8, in particular to keep the rotational speed of the output shaft 8 and the torque at the output shaft 8 constant or substantially constant. It is emphasized that, during use, the rotational speed of and torque at the input shaft 7 depends on the rotational speed of the wind turbine operationally connected to the input shaft 7, and the torque applied thereto. So, the controller 40 is configured to monitor the rotational speed of and the torque at the output shaft 8 constantly or periodically, for example by monitoring the frequency of the electrical power put out of the system for optimizing angular speed and torque, configured for generating electrical power.

[0072] When it is determined that the rotational speed and / or the torque of the output shaft 8 is too high, i. e. above a predetermined threshold, the controller 40 controls each or both of the first power convertor 42 and the second power convertor 43 to extract electrical energy from the electromagnets 12, 33 of the outer stator 10 and / or the output rotor 30, respectively. As a result, the rotational speed and torque at the output shaft 8 will be lowered, so that they may fall in the optimal working range of a power generator operatively connected to the output shaft 8.

[0073] In the opposite, when it is determined that the rotational speed and / or the torque of the output shaft 8 is too low, i. e. below a predetermined threshold, the controller 40 controls each or both of the first power convertor 42 and the second power convertor 43 to inject electrical energy into the electromagnets 12, 33 of the outer stator 10 and / or the output rotor 30, respectively. As a result, the rotational speed and torque at the output shaft 8 will be raised, so that they may fall in the optimal working range of a power generator operatively connected to the output shaft 8.

[0074] In summary, the controller 40 is configured for maintaining the rotational speed and / or torque of the output shaft 8 substantially constant or constant, despite fluctuations of the rotational speed and / or torque of the input shaft 7.

[0075] An isometric view of an electromagnetic transmission device 100 of a system for optimizing angular speed and torque, configured for generating electrical power according to another embodiment of the invention is shown in figure.

[0076] The electromagnetic transmission device 100 according to the present embodiment is also provided with a housing 102, in particular a cylindrical shaped housing 102. Within the housing 102, a transmission space 103 is defined in which transmission of the input rotational movement to the output rotational movement takes place. The housing 102 further includes a first closed end 104, and a second closed end 105, wherein an input shaft 106 extends through the first closed end 104 into the transmission space 103, and an output shaft 107 extends through the second closed end 105 into the transmission space 103. Additionally, at the outer circumference thereof, the housing 102 is provided with mounting projections 101, which project radially outwards from the outer circumference of the housing 102. As shown in figure 5, the input shaft 106 extends into and through the majority of the transmission space 103. Near the end of the input shaft 106 within the transmission space 103, the input shaft 106 is provided with an input rotor 110, that is fixed to the input shaft 106 such that rotation of the input shaft 106 results in rotation of the input rotor 110. The input rotor 110, as best shown in figure 6, is provided with N permanent magnets 111 at the outer circumference thereof. The permanent magnets 111 have magnetic north and south poles, and are arranged in such manner that the north and south poles of the permanents magnets 111 are alternating in the circumferential direction thereof. Due to this construction, rotation of the input shaft 106 around the longitudinal axis L thereof, results in rotation of the input rotor 110 and thus the permanent magnets 111 around the longitudinal axis L.

[0077] The electromagnetic transmission device 100 is further provided with a output rotor 115 arranged around the input rotor 110. As shown in figure 5, the input rotor 110 has a first height, and the output rotor 115 has a second height, wherein the first height is larger than the second height. The output rotor 115 has a hollow cylindrical wall 116. At the inner circumference of the hollow cylindrical wall 116, a number of, in particular M, electromagnets 117 are arranged that face towards the permanent magnets 111 at the input rotor 110. As best shown in figure 6, each of the electromagnets 117 has a T-shaped portion 118 of which the bottom is connected to the inner circumference of the hollow cylindrical wall 116. Although not shown, an electric wire is wound around the T-shaped portion 118, which electric wire is connected to a power source as elucidated below, and each of the electromagnets 117 is connected to a controller configured for selectively activating the electromagnets 117.

[0078] A shield 120 is arranged around the output rotor 115 and the input rotor 110, which shield 120 is configured for shielding the magnetic fields of the permanent magnets 111 and the electromagnets 117. The shield 120 has a further hollow cylindrical wall 121 that is connected to the outer circumference of the hollow cylindrical wall 116 two or more set screws 122. Therefore, the shield 120 rotates around the longitudinal axis L when the input rotor 110 and the output rotor 115 rotate around the longitudinal axis L.

[0079] At one end of the further hollow cylindrical wall 121, i. e. the top end in figure 5, the further hollow cylindrical wall 121 is closed by means of a first end cap 125 through which the input shaft 106 extends. At the other end of the further hollow cylindrical wall 121, i. e. the lower end in figure 5, the further hollow cylindrical wall 121 is closed by means of a second end cap 126 through which the input shaft 106 extends.

[0080] As best shown in figure 5, at the end of the second end cap 126 facing away from the first end cap 125, the output shaft 107 is connected to the second end cap 126 by means of connecting screws 127. Upon rotation of the output rotor 115 and, thus, the shield 120, the output shaft 107 also rotates.

[0081] Between the first end cap 125 and the first closed end 104 of the housing 102, a sleeve 130 is provided around the input shaft 106. The sleeve 130 is fixed to the first closed end 104 at the side thereof facing towards the transmission space 103. At the end of the sleeve 130 that merges into the first closed end 104, a first bearing 131 is provided within the sleeve 130 and around the input shaft 106, thereby allowing rotation of the input shaft 106. At the end of the sleeve 130 facing towards the first end cap 125, a second bearing 132 is provided between the respective end of the sleeve 130 and the first end cap 125, and around the input shaft 106. Furthermore, a third bearing 133 is provided between the first end cap 125 and the end of the input rotor 110 facing towards the first end cap 125, and around the input shaft 106. A fourth bearing 134 is provided between the second end cap 126 and the end of the input rotor 110 facing towards the second end cap 126, and around the input shaft 106.

[0082] As shown in figure 5, in order to connect the electromagnets 117 to a power source, a slip ring 140 is provided, which slip ring 140 is arranged between the first end cap 125 and the first closed end 104 and around the sleeve 130. The slip ring 140 is provided with a wire output 141 for electrically connecting the slip ring 140 to a not shown power source, and with coil wires 142 extending between the slip ring 140 and the electromagnets 117 to provide and / or receive electric energy to and / or from the electromagnets 117.

[0083] Although not shown, electromagnetic transmission device 100 further comprises a controller that is operatively connected to the output rotor 115, in particular the plurality of electromagnets 117 thereof. Additionally, an energy storage, such as a battery, is provided, which energy storage is electrically connected to the output rotor 115 via a first power convertor.

[0084] In summary, the controller is configured for maintaining the rotational speed of the output shaft 107 substantially constant or constant, despite fluctuations of the rotational speed of the input shaft 106.

[0085] The electromagnetic transmission device 1, 100 as described above may be used in combination with a wind turbine, such as a vertical axis wind turbine, in order to form a power energy system.

[0086] An isometric view of a vertical axis wind turbine 200 for use in combination with the described electromagnetic transmission device in a system for optimizing angular speed and torque, configured for generating electrical power according to an embodiment of the invention is shown in figure 7.

[0087] The vertical axis wind turbine 200, in short, has a vertical axis 201 with a bottom end 202 and a top end 203. At the bottom end 202, an electromagnetic transmission device 1, 100 is provided for converting rotational movement of the vertical axis 201 into electrical energy. At the top end 203, a drive 204 is provided that is operatively connected to a slider 205 arranged at the vertical axis 201 and configured for being moved along the vertical axis 201 in an upwards or downwards direction, wherein movement of the slider 205 is realized by means of the drive 204.

[0088] As shown in figure 7, the vertical axis wind turbine 200 is provided with a number of turbine blades 206. Each of the turbine blades 206 is connected to the vertical axis 201 by means of a first connecting rod 207 connected thereto near the lower end of the respective turbine blade 206, which first connecting rod 207 in its turn is connected to a connector 208 at the vertical axis 201 at or near the lower end thereof. Further, each of the turbine blades 206 is connected to the vertical axis 201 by means of a second connecting rod 209 connected thereto near the upper end of the respective turbine blade 206, which second connecting rod 209 in its turn is connected to the slider 205. When the slider 205 is in the most upward position thereof, each of the turbine blades 206 is orientated substantially parallel to the vertical axis 201. When the slider 205 is in the most downward position thereof, each of the turbine blades 206 is orientated at an angle with respect to the vertical axis 201, as shown in figure 7. By moving the slider 205 upwards or downwards, the swept area of the vertical axis wind turbine 200 is increased or decreased, respectively. Increasing the swept area results in the turbine blades 206 extending over a larger area. When the force applied to the vertical axis wind turbine 200 by the wind increases, the torque will also increase, when the turbine blades 206 remain in the same position. When it is determined that the torque is above the predetermined torque threshold, the turbine blades 206 are moved towards the retracted position to decrease the area covered by the turbine blades 206. As the torque at the input shaft 106 decreases, the rotational speed of the input rotor 110 decreases, which results in a lower rotational speed of the output shaft 107. As the electromagnetic transmission device 100 is configured for maintaining the rotational speed of the output shaft 107 within a predetermined range, the electromagnetic transmission device 100 will increase the rotational speed of the output shaft. 107 by injecting electrical energy. This results in that the connected generator may provide a consistent power output. When it is determined that the torque is below the predetermined torque threshold, the opposite happens.

[0089] It is to be understood that the above description is included to illustrate the operation of the preferred embodiments and is not meant to limit the scope of the invention. From the above discussion, many variations will be apparent to one skilled in the art that would yet be encompassed by the scope of the present invention.

Claims

C L A I M S1. System for optimizing angular speed and torque, configured for generating electrical power configured for generating electrical power, the system comprising:a wind turbine having a turbine output shaft operatively connected to the input shaft of an electromagnetic transmission device;an electromagnetic transmission device for transmission of a rotational movement operatively connected to the turbine output shaft and configured for transmitting the rotational input to an electrical power generator; and an electrical power generator having a generator input shaft operatively connected to the electromagnetic transmission device, and an output for outputting electrical power,wherein the electromagnetic transmission device, comprises:an input rotor with an input shaft operatively connected thereto that is operatively connected to the turbine output shaft;an output rotor arranged concentrically with the input rotor, and with an output shaft operatively connected thereto that is operatively connected to the generator input shaft;wherein one of the input rotor and the output rotor is provided with a plurality of electromagnets arranged thereon, andwherein the system comprises a controller operatively connected to the plurality of electromagnets and configured for maintaining the rotational speed of the generator input shaft within a predetermined range by injecting and / or retracting electrical power into and / or from the plurality of electromagnets, anda torque adjustment module for adjusting thetorque applied to the generator input shaft, wherein the torque adjustment module is operatively connected to the controller and the controller is configured for maintaining the torque applied within a predetermined range.

2. System for optimizing angular speed and torque, configured for generating electrical power according to claim 1, wherein the controller further is configured for determining an output parameter of the electrical power put out at the output of the electrical power generator, and for comparing the output parameter with a predetermined threshold in order to determine whether the determined output parameter is above or below the predetermined threshold.

3. System for optimizing angular speed and torque, configured for generating electrical power according to claim 2, wherein the controller is configured to inject electrical power into the plurality of electromagnets and / or to control the torque adjustment module to increase the torque applied, when it is determined that the determined output parameter is below the predetermined threshold.

4. System for optimizing angular speed and torque, configured for generating electrical power according to claim 2 or 3, wherein the controller is configured to extract electrical power from the plurality of electromagnets and / or to control the torque adjustment module to decrease the torque applied, when it is determined that the determined output parameter is above the predetermined threshold.

5. System for optimizing angular speed and torque, configured for generating electrical power according to any one of claims 2-4, wherein the output parameter is selected from the group comprising frequency of the electrical energy at the output of the electrical power generator.

6. System for optimizing angular speed and torque, configured for generating electrical power according to any one of claims 2-5, wherein the controller isconfigured to control the torque adjustment module firstly, whereafter electrical power is injected into or extracted from the plurality of electromagnets, preferably wherein the torque adjustment module is further configured for adjusting the RPM of the input rotor.

7. System for optimizing angular speed and torque, configured for generating electrical power according to any one of the preceding claims, comprising an energy storage and an electrical power convertor, wherein the energy storage is electrically connected to the electrical power convertor, and the electrical power convertor is electrically connected to the plurality of electromagnets, orcomprising an electrical power convertor and a grid connector operatively connected to the electrical power convertor and configured for being connected to an energy grid.

8. System for optimizing angular speed and torque, configured for generating electrical power according to claims 3 and 7, wherein the controller is configured to operate the electrical power convertor to extract electrical power from the energy storage or from the energy grid, when it is determined that the determined output parameter is below the predetermined threshold.

9. System for optimizing angular speed and torque, configured for generating electrical power according to claims 4 and 7, and optionally 8, wherein the controller is configured to operate the electrical power convertor to extract electrical power from the electromagnetic transmission device and / or torque adjustment module, and to inject the extracted electrical power into the energy storage or into the energy grid, when it is determined that the determined output parameter is above the predetermined threshold.

10. System for optimizing angular speed and torque, configured for generating electrical power according to any one of the preceding claims, wherein theelectromagnetic transmission device comprises a cylindrical housing defining a transmission space and having a first closed end and a second closed end, opposite to each other, wherein the input rotor and the output rotor are arranged within the transmission space.

11. System for optimizing angular speed and torque, configured for generating electrical power according to any one of the preceding claims, wherein the other one of the input rotor and the output rotor is provided with a number of permanent magnets arranged thereon.

12. System for optimizing angular speed and torque, configured for generating electrical power according to any one of the preceding claims, wherein the torque adjustment module comprises a stator arranged within the electromagnetic transmission device and comprising a further plurality of electromagnets, andwherein the controller is operatively connected to the further plurality of electromagnets of the outer stator and is configured for controlling the torque of the output shaft by injecting and / or retracting electrical power into and / or from the further plurality of electromagnets.

13. System for optimizing angular speed and torque, configured for generating electrical power according to any one of the preceding claims, wherein the output rotor is arranged within the input rotor, and wherein the output rotor comprises the plurality of electromagnets and the input rotor comprises the number of magnets.

14. System for optimizing angular speed and torque, configured for generating electrical power according to claim 13, wherein the input rotor comprises an input cylindrical wall arranged concentrically about the output rotor, wherein the number of magnets is provided at the inner circumference of the input cylindrical wall and are distributed evenly over the inner circumference, when seen in circumferential direction.

15. System for optimizing angular speed and torque, configured for generating electrical power accordingto claim 14, wherein each of the number of magnets has a magnetic north and south pole, and wherein the magnets are arranged in such manner that the north and south poles of the magnets are alternating in the circumferential direction.

16. System for optimizing angular speed and torque, configured for generating electrical power according to claim 12, and any one of the claims 14-15, wherein the number of magnets is also provided at the outer circumference of the input cylindrical wall and are distributed evenly over the outer circumference, when seen in circumferential direction.

17. System for optimizing angular speed and torque, configured for generating electrical power according to any one of the claims 1-12, wherein the input rotor is arranged within the output rotor, and wherein the input rotor comprises the number of magnets, and the output rotor comprises the plurality of electromagnets.

18. System for optimizing angular speed and torque, configured for generating electrical power according to claim 17, wherein the number of magnets is arranged at the outer circumference of the input rotor, and such that the north and south poles of the magnets are alternating in the circumferential direction thereof, andwherein the output rotor comprises an output cylindrical wall and the plurality of electromagnets is arranged at the inner circumference of the output cylindrical wall.

19. System for optimizing angular speed and torque, configured for generating electrical power according to any one of the preceding claims, wherein the wind turbine is a vertical axis wind turbine having a vertical axis connected to the turbine output shaft, retractable turbine blade (s) connected to the vertical axis, and a drive operatively connected to the retractable turbine blade (s), wherein the retractable turbine blade (s) is (are) configured to be moved by means of the drive between an extendedposition, in which the retractable turbine blade (s) defines (define) a first swept area, and a retracted position, in which the retractable turbine blade (s) defines (define) a second swept area that is smaller than the first swept area,wherein the torque adjustment module is defined by the retractable turbine blade (s), andwherein the controller is operatively connected to the drive of the vertical axis wind turbine to control the position of the retractable turbine blade (s), so that the torque may be adjusted based on the turbine' s TSR ratio.

20. System for optimizing angular speed and torque, configured for generating electrical power according to claim 19, wherein the controller is configured to operate the drive of the vertical axis wind turbine to move the retractable turbine blade (s) towards the extended position, in order to increase the torque applied.

21. System for optimizing angular speed and torque, configured for generating electrical power according to claim 19 or 20, wherein the controller is configured to operate the drive of the vertical axis wind turbine to move the retractable turbine blade (s) towards the retracted position, in order to decrease the torque applied.

22. System for optimizing angular speed and torque, configured for generating electrical power according to any one of claims 19-21, comprising a blade pitch and arms adjusting mechanism operatively connected to turbine blade (s), and configured for adjusting the pitch and arms of at least one of the turbine blade (s).

23. Method for operating a system for optimizing angular speed and torque, configured for generating electrical power according to any one of the preceding claims, the method comprising the steps of:controlling the rotational speed of the output shaft by injecting and / or retracting electrical power into and / or from the plurality of electromagnets; and adjusting the torque applied to the output shaftfor maintaining the torque applied within a predetermined range.

24. Method according to claim 23, comprising the step of determining an output parameter of the electrical power put out at the output of the electrical power generator, and of comparing the output parameter with a predetermined threshold in order to determine whether the determined output parameter is above or below the predetermined threshold.

25. Method according to claim 24, comprising the step of injecting electrical power into the plurality of electromagnets and / or of controlling the torque adjustment module to increase the torque applied, when it is determined that the determined output parameter is below the predetermined threshold.

26. Method according to claim 24 or 25, comprising the step of extracting electrical power from the plurality of electromagnets and / or of controlling the torque adjustment module to decrease the torque applied, when it is determined that the determined output parameter is above the predetermined threshold.

27. Method according to any one of claims 23-26, wherein the electromagnetic transmission device is an electromagnetic transmission device according to claim 12, comprising the step of controlling the torque applied by injecting and / or retracting electrical power into and / or from the further plurality of electromagnets.

28. Method according to claim 24, wherein the step of determining an output parameter comprises determining the frequency of the electrical power put out at the output of the electrical power generator.

29. Electromagnetic transmission device for use in a system for optimizing angular speed and torque, configured for generating electrical power according to any one of the claims 1 to 22, or a method according to any one of claims 23 to 28, and as defined in any one of the claims 1 to 28.

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