Dynamic torque balancing mechanism in counter-rotating dual-rotor wind turbines
Patent Information
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- KOCAELI UNIVERSITESI
- Filing Date
- 2024-10-16
- Publication Date
- 2026-05-06
AI Technical Summary
Counter-rotating dual-rotor wind turbines face challenges in maintaining continuous operation at varying wind speeds due to mechanical losses in gearboxes and the inability to adjust blade pitch angles dynamically, leading to reduced efficiency and potential shutdown of the rear rotor.
A blade control and torque balancing mechanism that uses an active control method to measure torque values from the generator's rotor and stator, allowing for real-time adjustment of blade pitch angles on both the front and rear rotors to minimize torque differences and optimize energy capture.
The mechanism enables continuous operation of dual-rotor wind turbines across varying wind speeds, enhances energy production by optimizing torque output from both rotors, and reduces mechanical stress and noise, thereby improving overall efficiency and lifespan.
Smart Images
Figure TR2024051183_26062025_PF_FP_ABST
Abstract
Description
[0001] DYNAMIC TORQUE BALANCING MECHANISM IN COUNTER-ROTATING DUAL-ROTOR WIND TURBINES
[0002] Technical Field
[0003] The invention relates to a blade control and torque balancing mechanism that includes an algorithm capable of minimizing the torque difference generated by the front and rear rotors by instantaneously measuring the torque values produced by the generator rotor and stator through an active control method.
[0004] State of the Art
[0005] A counter-rotating dual-rotor wind turbine is designed to convert wind energy into electrical energy more efficiently. In this turbine, the two rotors rotate in opposite directions, which increases aerodynamic efficiency and enables the turbine to perform optimally across a wider range of wind speeds. This counter-rotational movement allows the rotors to capture wind flow more effectively, resulting in higher energy production efficiency. Compared to traditional single-rotor turbines, this design generates less mechanical stress and vibration, thereby reducing maintenance costs and extending the turbine's lifespan. This technology is particularly preferred in projects aiming to maximize energy yield from wind power.
[0006] Studies in the literature indicate that counter-rotating dual-rotor wind turbines are more efficient than both single-rotor wind turbines and dual-rotor wind turbines with rotors rotating in the same direction. There are various methods for connecting the rotors to the generator in a counterrotating dual-rotor wind turbine. One such method involves combining the motion of the two counter-rotating rotors using a planetary gear, which is then connected to the generator’s shaft via a single shaft. In this way, the planetary gear makes it possible to combine the movement of both rotors. However, in this design, the stator remains stationary while the rotor rotates. The main disadvantage of this method is the mechanical losses that occur within the gearbox, which diminish the advantages inherent to dual-rotor wind turbines. In single-rotor wind turbines, the stator of the generator is fixed, and the rotor of the wind turbine is connected to the generator’s rotor. The electromechanical force generated within the generator is resisted by the body of the wind turbine, as the stator is fixed to the turbine body. In dual-rotor wind turbines, the front rotor captures part of the energy from the wind, thereby decreasing the wind speed that reaches the rear rotor. Consequently, the rear rotor receives a reduced wind speed with partially depleted energy. When connected to a load, the electromechanical force generated within the generator is resisted by the rear rotor. If the rear rotor cannot produce sufficient aerodynamic torque, this electromechanical force forces the rear rotor to come to a halt. When the rear rotor stops, the system essentially functions as a single-rotor turbine, negating the benefits of a dual-rotor design. In small wind turbines, the blade pitch angles are generally fixed, meaning that the blades are attached to the rotor without any mechanism to alter the blade angles. In studies using a similar design, it has been observed that the rear rotor stops at certain wind speeds, reducing the dual-rotor turbine to a single-rotor operation and thus rendering it ineffective.
[0007] In the literature, attempts have been made to create a stable system by varying parameters such as blade profiles, blade pitch angles, and chord lengths on both the front and rear rotors. However, in dual-rotor systems with fixed blade angles, it has not been possible for the blades to continue rotating at variable speeds. Similar issues have been encountered in different designs developed by researchers, where the rear rotor was observed to stop at certain wind speeds and blade angles. Many studies have implemented gear systems, which not only increase noise levels but also reduce the efficiency of the wind turbine. The rotor and stator of the wind turbine are attached to two different shafts: one shaft is connected to the front blade group, and the other to the rear blade group. The primary challenge in dual-rotor wind turbines lies in ensuring continuous operation at varying wind speeds. Some systems operate by manually adjusting the blade angles of the front and rear blades for a fixed wind speed. However, in variable wind speeds, the system must be completely stopped, the blade angles readjusted, and then restarted, which renders the practical application of dual-rotor wind turbines infeasible.
[0008] In conclusion, the necessity of a dynamic torque balancing mechanism in counter-rotating dualrotor wind turbines has become evident, as it addresses the disadvantages present in the existing technology. The inadequacy of current solutions has made advancements in this technical field essential.
[0009] Summary of the Invention
[0010] The present invention relates to a blade control and torque balancing mechanism that, by employing an active control method, includes an algorithm capable of minimizing the torque difference generated by the front and rear rotors. This algorithm achieves this by instantaneously measuring the torque values produced by the generator's rotor and stator, thus addressing the aforementioned requirements, eliminating all disadvantages, and introducing additional advantages. Based on the state of the art, the invention aims to enable adjustment of the blade pitch angles of both the front and rear rotors in counter-rotating dual-rotor wind turbines, using a decision mechanism based on wind speed.
[0011] The invention aims to ensure instantaneous measurement of the torque generated by the front and rear rotors while adjusting the blade angles via the blade control and torque balancing mechanism. Another aim of the invention is to allow the wind turbine to optimally adapt to constantly changing wind conditions by enabling real-time control of the blade pitch angles for both the front and rear rotors.
[0012] A further aim of the invention is to enable optimal utilization of wind energy by adjusting the angle of the front rotor blades using the blade control and torque balancing mechanism when wind speeds vary.
[0013] Another purpose of the invention is to enhance the performance of the rear rotor and enable the front rotor to capture wind energy more effectively, thereby increasing overall energy production.
[0014] Additionally, the invention seeks to allow the rear rotor to continue generating torque and capture more wind energy by reducing the speed of the front rotor and optimizing its pitch angle at certain wind speeds.
[0015] Another objective is to increase wind energy efficiency by maximizing total torque production, as the blade control and torque balancing mechanism aims for both rotors to capture maximum energy.
[0016] The structural and characteristic features of the invention, as well as all its advantages, will be more clearly understood through the detailed description provided below, with references to the accompanying figures. Therefore, the evaluation should be made by considering these figures and the detailed explanations.
[0017] Brief Description of the Figures
[0018] For the best understanding of the structure of the present invention, along with its additional elements and advantages, it should be evaluated together with the figures described below.
[0019] • Figure 1 : A schematic general view of the blade control and torque balancing mechanism.
[0020] • Figure 2: A schematic detailed view of the generator, servomotor, and torque meter.
[0021] • Figure 3: A schematic top view of the blade control and torque balancing mechanism Reference Numbers
[0022] 100: Blade control and torque balancing mechanism
[0023] 101 : Generator
[0024] 102: Slip ring
[0025] 103: Bearing
[0026] 104: Coupling
[0027] 105: Servomotor
[0028] 106: Torque meter
[0029] 107: Fixed bearing
[0030] 108: Lead screw
[0031] 109: Lead screw connection apparatus
[0032] 110: Connection arm
[0033] 111 : T riangular connection apparatus
[0034] 112: Blade control apparatus
[0035] 113: Blade Connection Part
[0036] 114: Turbine blades
[0037] 115: Adjustable torque meter connection apparatus
[0038] 116: Generator connection supports
[0039] 117: Shaft
[0040] 118: Blade movement connection apparatus
[0041] Detailed Description of the Invention
[0042] In this detailed description, the blade control and torque balancing mechanism (100) involved in the invention, which uses an active control method to instantaneously measure the torque values produced by the generator (101) rotor and stator to minimize the torque difference between the front and rear rotors, is described as an example to facilitate understanding and should not be considered limiting. Numerous numerical and experimental studies have demonstrated that dual-rotor wind turbines are more efficient than traditional turbines. Counter-rotating wind turbines, in particular, have lower starting torque and reduced torque fluctuations. They can generate more power at any wind speed, produce lower noise, and vibrate less compared to conventional wind turbines. However, they require complete shutdown and manual adjustment of the turbine blade (114) angles to resume operation under variable wind speeds. The blade control and torque balancing mechanism (100) shown in Figure 1 addresses this issue by allowing real-time control of the blade pitch angles for both the front and rear turbine blades (114). This mechanism enables the wind turbine to optimally adapt to constantly changing wind conditions. Specifically, in cases of variable wind speeds, the blade control and torque balancing mechanism (100) adjusts the angle of the turbine blades (114) on the front rotor, ensuring optimal utilization of wind energy.
[0043] The blade control and torque balancing mechanism (100) is developed to enhance the performance of the rear rotor by enabling the front rotor to capture wind energy more effectively, thereby increasing total energy production. At certain wind speeds, it allows the front rotor to slow down, enabling the rear rotor to capture more wind energy, thus maintaining its rotation by producing more torque. While single-rotor wind turbines typically focus on maximizing energy from a single rotor, this invention has been specifically developed for dual-rotor designs. The blade control and torque balancing mechanism (100) aims to maximize energy capture for both rotors, thereby increasing total torque output and enhancing wind energy efficiency. The primary components of the blade control and torque balancing mechanism (100) comprises a servomotor (105), lead screw (108), torque meter (106), connection arm (110), and triangular connection apparatus (111), which decision the angles of the front and rear turbine blades (114) based on the torque values obtained from the torque meters (106) with the servomotor (105) adjusting the angles by the driving force.
[0044] The generator (101 ) shown in Figure 2 generates alternating current. The generator’s (101) rotor and stator are attached to two different shafts. It consists of two covers and an outer shell containing bearing housings and circlip slots, allowing the rotor and stator to rotate independently. The generator’s (101) cables are connected to a slip ring (102). Since the stator is typically stationary in conventional designs, there is no need for an additional connection in the cables. However, since the stator also moves in the blade control and torque balancing mechanism (100), the cables exiting the generator (101) also move, necessitating the use of a slip ring (102) to transmit energy through the cables. The generator (101) is secured to the base plate using generator connection supports (116) and bearings (103). The torques generated by the front and rear turbine blades (114) are measured by torque meters (106). The shafts exiting the rotor and stator are connected to couplings (104) and then to torque meters (106), which are fixed in place with adjustable torque meter connection apparatuses (115). One side of each coupling (104) is connected to the torque meter (106), while the other side is attached to the shaft (117). At the end of the shaft (117), there is a blade connection part (113). The blade connection part (113), which allows the turbine blades (114) to move, contains bearing holes for the shafts (117) and holes for attaching the shaft (117). The turbine blades (114) are connected to this blade connection part (113) via bearings (103). The blade movement connection apparatus (118) is mounted on the shaft (117) before the blade connection part (113) to allow adjustment of the desired angle of the turbine blades (114). The blade movement connection apparatus (118) shown in Figure 3 enables active adjustment of the turbine blade (114) angle. The angles are adjusted via the servomotor (105) based on active torque measurements and a decision mechanism. The servomotor (105) is connected to the lead screw (108) through a coupling (104). The lead screw (108) is fixed to the base plate via fixed bearings (107). To transmit the motion of the lead screw (108) to the turbine blades (114), a lead screw connection apparatus (109) and a connection arm (110) attached to the lead screw connection apparatus (109) are used. The connection arm (110) moves along the shaft (117). Inside the connection arm (110), the shaft (117) rotates with the turbine blades (114). The servomotor (105) moves the lead screw (108) back and forth, enabling the connection arm (110) to move accordingly. The triangular connection apparatus (111) is mounted on the connection arm
[0045] (110). The elliptical triangular connection apparatus (111) has components that attach to the moving connection arms (110) of the turbine blades (114), allowing simultaneous rotation with the turbine blades (114) due to the bearing connection inside. This triangular connection apparatus
[0046] (111 ) is connected to the blade control apparatus (112). As the connection arm (110) moves forward and backward, the triangular connection apparatus (111) also moves, thus changing the angles of the turbine blades (114).
[0047] The blade control and torque balancing mechanism (100) in this invention enables more efficient energy production in wind energy plants. It provides more efficient and sustainable energy solutions for energy production and distribution companies. Companies focused on green energy can integrate the dual-rotor turbine design to contribute to sustainable energy production.
Claims
CLAIMS1. A blade control and torque balancing mechanism (100) developed for use in dualrotor wind turbines, characterized by comprising; a generator (101) consisting of two covers and an outer shell, containing bearing housings and circlip slots inside, allowing the rotor and stator connected to two different shafts to rotate in opposite directions;- a servomotor (105) connected to a lead screw (108) for changing angles based on active torque measurement and decision mechanism;- the lead screw (108) moved forward and backward by the servomotor (105);- a torque meter (106) connected to the shafts exiting the generator (101 ) rotor and stator for measuring the torque from the front and rear turbine blades (114);- a connection arm (110) that moves along the lead screw (108), allowing a shaft (117) to rotate with the turbine blades (114);- a triangular connection apparatus (111) that elliptical edges on which the connection arms (110) are connected, containing bearing and circlip holes for mounting the shaft (117) and servomotor (105) inside, enabling synchronous rotation with the turbine blades (114) and moving with the forward and backward movement of the connection arm (110) to adjust the angles of the turbine blades (114);- a blade movement connection apparatus (118) positioned on the shaft (117) for adjusting the desired angle by actively changing the angle of the turbine blades (114).
2. The blade control and torque balancing mechanism (100) according to Claim 1 , characterized by comprising; a slip ring (102) connected to the cables exiting from the generator (101) and movement.
3. The blade control and torque balancing mechanism (100) according to Claim 1 , characterized by comprising; a generator connection supports (116) for mounting and securing the generator (101) on the base plate.
4. The blade control and torque balancing mechanism (100) according to Claim 1 , characterized by comprising; a coupling (104) connected on one side to the torque meter (106) and on the other to the shaft (117) from the generator (101 ) rotor and stator.
5. The blade control and torque balancing mechanism (100) according to Claim 1 , characterized by comprising; an adjustable torque meter connection apparatus (115) for securing the torque meters (106).
6. The blade control and torque balancing mechanism (100) according to Claim 1 , characterized by comprising; a blade connection part (113) positioned at the end of the shaft (117) to allowing movement of the turbine blades (114), on which bearing holes for the shafts (117) and holes for securing the shaft (117).
7. The blade control and torque balancing mechanism (100) according to Claim 1 , characterized by comprising; a bearing (103) that connects the turbine blades (114) to the blade connection part (113).
8. The blade control and torque balancing mechanism (100) according to Claim 1 , characterized by comprising; a fixed bearing (107) for securing the lead screw (108) to the base plate.
9. The blade control and torque balancing mechanism (100) according to Claim 1 , characterized by comprising; a lead screw connection apparatus (109) for transmitting the movement of the lead screw (108) to the turbine blades (114).
10. The blade control and torque balancing mechanism (100) according to Claim 1 , characterized by comprising; a blade control apparatus (112) connected to the triangular connection part (111).