A blade mounting structure for a central opening annular tidal current power generation device

Abstract

The application discloses a paddle mounting structure of a center-opening annular tidal current energy power generation device. The annular stator is annular and internally provided with a stator winding, and the outer wall is provided with a mounting interface; the annular rotor is annular and coaxially arranged on the inner side of the annular stator; a water-lubricated bearing is arranged between the annular stator and the annular rotor and used for supporting the annular rotor to rotate relative to the annular stator; a plurality of paddles are radially and uniformly distributed along the circumference and fixed to the inner wall of the annular rotor; a through-flow channel without a center shaft is formed in the center of the device, and the through-flow channel is provided with the plurality of paddles for flow guiding. The structure of the application is compact, the impeller is uniformly stressed, the tidal current kinetic energy can be effectively converted into electric energy, the power generation efficiency is obviously improved compared with a traditional paddle type device, and the application is suitable for a medium-low flow speed tidal current energy development scene such as a coastal area, a strait and a river mouth.

Description

Technical Field

[0001] This invention relates to the field of marine renewable energy technology, and specifically designs a blade mounting structure for a centrally open annular tidal current power generation device, which can generate electricity at low tidal current velocities. Background Technology

[0002] Tidal energy, with its high energy density and strong predictability, has become a key development direction in the field of marine renewable energy. Among the many energy capture technologies, horizontal axial-flow turbines are currently the mainstream technology for engineering applications, but their inherent technical bottlenecks are becoming increasingly prominent. The core disadvantage of this traditional equipment stems from its mechanical structure. It relies on a drive shaft running through the center of the flow channel and a complex multi-stage support bearing system, resulting in a bulky structure and high manufacturing costs. In the harsh marine environment of corrosion, erosion, and biofouling, the bearings and sealing components of this structure are prone to failure, leading not only to low reliability but also to frequent and costly maintenance.

[0003] Secondly, regarding energy efficiency, the solid central shaft and supporting structure significantly obstruct the inflow of water, generating unnecessary flow resistance and eddy current losses, thus reducing water energy capture efficiency. Simultaneously, the lengthy mechanical transmission path, accompanied by significant friction and transmission losses, further restricts the improvement of the overall system efficiency. Its environmental adaptability and maintainability are also poor. The central shaft structure makes the impeller susceptible to entanglement by fishing nets, seaweed, and other marine debris, and the internal precision components are easily worn by suspended particles. In the event of a malfunction, it often requires complex and costly overall hoisting and repair, resulting in extremely poor maintainability. Summary of the Invention

[0004] To address the inherent shortcomings of traditional axial flow equipment in terms of structure, efficiency, and maintainability, and in order to efficiently capture tidal energy and improve the environmental adaptability and maintainability of the equipment, this invention designs a blade mounting structure for a centrally open annular tidal energy generation device by eliminating the central shaft system and adopting rim drive technology. This eliminates the need for a complex mechanical transmission system and provides a more efficient, reliable, and economical solution for tidal energy generation technology.

[0005] The technical solution of this invention is: The annular stator is annular in shape and has stator windings inside. Its outer wall has an installation interface for fixing to an external foundation. The annular rotor is arranged in a ring shape and coaxially inside the annular stator, and the annular interior is provided with an array of permanent magnets that cooperate with the stator windings. A water-lubricated bearing is disposed between the annular stator and the annular rotor to support the rotation of the annular rotor relative to the annular stator. Multiple blades are radially and evenly distributed along the circumference and fixed to the inner wall of the annular rotor; wherein, a flow channel without a central axis is formed in the center of the device, and multiple blades guide the flow in the flow channel.

[0006] The annular stator has an annular groove on its inner circumferential surface. An annular rotor is embedded in the annular groove through a water-lubricated bearing. Multiple blades are evenly distributed and fixed on the inner circumferential surface of the annular rotor. The outer end of each blade is fixed on the inner circumferential surface of the annular rotor, and the inner end extends towards the center and extends to a position close to the center of the annular stator and the annular rotor, so that an axially through central opening flow channel is formed between the inner ends of each blade as a flow channel.

[0007] The blades adopt a modular independent installation structure. Each blade has a mounting flange at its root and is rigidly and detachably connected to the inner wall of the annular rotor by fasteners.

[0008] The permanent magnet array is a permanent magnet array consisting of multiple permanent magnets arranged at uniform intervals along the circumference, with each permanent magnet forming the mounting and bearing base at the outer end of the propeller blade.

[0009] The blade specifically includes a blade body mounting flange and a streamlined transition section. The mounting flange is fixedly connected to the corresponding permanent magnet in the permanent magnet array on the inner circumference of the annular rotor. The mounting flange of the blade has an arc-shaped contact surface that matches the curvature of the inner wall of the annular rotor. The root of the blade body is fixedly connected to the mounting flange via the streamlined transition section.

[0010] The annular rotor and annular stator form a gearless direct-drive permanent magnet generator structure. The water flow impacts the blades, driving the annular rotor to rotate and directly cutting magnetic field lines to generate electricity.

[0011] The airfoil section of the blades is symmetrically designed along the central axis, enabling the device to capture energy equally in both forward and reverse currents without the need for a pitch control mechanism.

[0012] The annular stator has several standardized mounting holes or slots on its two end faces or outer circumference as mounting interfaces for connection with seabed pile foundations, floating platforms or duct structures.

[0013] This invention employs a coaxial cylindrical structure consisting of an outer stator, a middle rotor, and inner blades. From the outside in, the structure comprises: an annular stator fixed to a supporting structure; an annular rotor supported by water-lubricated bearings; and multiple blades radially mounted on the inner wall of the rotor. The blades radiate towards the center but are not centrally connected, forming a centrally open channel to achieve axial water intake, radial work, and central drainage. The blades are connected to the rotor using flange bolts, with a rounded transition at the root to reduce stress concentration and ensure structural reliability under water flow impact. This device integrates a water turbine and a permanent magnet generator, with the rotor serving as both the blade support ring and the permanent magnet carrier, enabling gearless direct-drive power generation. The stator is fixed on the outside for easy waterproof encapsulation and electrical maintenance. The water-lubricated bearing system eliminates the complexity of traditional sealed lubrication, significantly reducing maintenance costs. The centrally open design eliminates traditional hub blockage, greatly reducing water flow resistance loss, creating a low-pressure suction zone to enhance flow velocity, and reducing wake interference, making it suitable for dense array deployment. The symmetrical blade structure gives the device a natural bidirectional power generation capability, allowing it to adapt to reciprocating currents without the need for a pitch control mechanism.

[0014] The blades are radially and symmetrically fixed to the inner wall of an annular rotor assembly using flange bolts. The tips of all blades point towards the center but are not connected to each other, thus forming a smooth flow channel at the center of the device. This installation method directly defines the overall "three-layer coaxial" configuration of the device: from the outside to the inside, there is an annular outer stator fixed to the support structure, an annular middle rotor supported by a bearing system (serving as the blade mounting base and permanent magnet carrier), and multiple radially embedded blades.

[0015] The aforementioned annular rotor serves as the inner rotor of a permanent magnet direct-drive generator (in the abstract, it is described as an inner rotor and outer stator structure; in the invention description, it is described as an outer stator and middle rotor structure). Its inner wall serves as the mounting base for the blades, and its outer wall is fitted with permanent magnets. The rotor is supported on the stator or support structure by a water-lubricated bearing system, achieving low-friction rotation driven by water flow.

[0016] The aforementioned annular stator: The stator serves as the outer stator of the permanent magnet direct-drive generator, with coil windings arranged internally and fixed to an external support arm or seabed foundation. The stator is waterproofly encapsulated for easy electrical maintenance.

[0017] The maintainability mentioned above: The modular connection between the blades and the rotor allows individual blades to be disassembled and maintained independently, without the need for overall hoisting and maintenance, thus improving the maintainability of the equipment.

[0018] The beneficial effects of this invention include: High flowability and anti-entanglement: The central opening design allows fish and floating objects to pass directly through, solving the entanglement problem of traditional water turbines, and utilizes the high linear velocity area on the outer edge to do work, resulting in higher power generation efficiency.

[0019] Modular maintenance: The blades and rotor are connected by flange bolts. When a blade is damaged, a diver or underwater robot can replace the blade independently by simply removing the corresponding bolts, without disassembling the entire motor or rotor.

[0020] Compact and reliable structure: The gearbox and spindle have been eliminated, enabling direct-drive power generation. Combined with water lubrication technology, this greatly improves the system's reliability and maintenance-free cycle. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall three-dimensional structure of the annular tidal current power generation device with a central opening according to the present invention.

[0022] Figure 2 This is a side cross-sectional view of the device of the present invention, showing the layout of the outer stator, the middle rotor and the central flow channel.

[0023] Figure 3 This is a partially enlarged schematic diagram of the connection between the blade and the rotor of the present invention.

[0024] Figure 4 This is a structural diagram of the internal rotor and blades of the device of the present invention after the stator housing has been removed.

[0025] Figure 5 This is a structural diagram of a single blade and its root mounting flange.

[0026] The labels in the diagram are as follows: 1-Annular stator, 2-Annular rotor, 3-Blade, 301-Blade body, 302-Mounting flange, 303-Streamlined transition section, 4-Water-lubricated bearing, 5-Center open flow channel, 6-Mounting interface. Detailed Implementation

[0027] The present invention will now be described in further detail with reference to the accompanying drawings.

[0028] like Figure 1 and Figure 2 As shown, the present invention provides a centrally open annular tidal current power generation device, which is generally annular in shape. It mainly consists of a stationary annular stator 1 and a rotating annular rotor 2. The outer circumferential surface of the annular stator 1 is provided with several mounting interfaces 6, such as grooves or screw holes as shown in the figure, for rigidly fixing the entire device to a seabed base or other carrier without the need for an integrated long support arm, making the installation more flexible.

[0029] like Figure 1 and Figure 2 As shown, it includes: The annular stator 1 is annular in shape and has stator windings inside, and has an installation interface 6 on its outer wall for fixing to an external foundation. The annular rotor 2 is arranged in annular shape and coaxially inside the annular stator 1; A water-lubricated bearing 4 is disposed between the annular stator 1 and the annular rotor 2 to support the annular rotor 2 to perform low-friction rolling rotation relative to the annular stator 1. Multiple blades 3 are radially and evenly distributed along the circumference and fixed on the inner wall of the annular rotor 2, i.e., the inner circumferential surface; wherein, a flow channel without a central shaft is formed in the center of the device, and multiple blades 3 guide the flow in the flow channel.

[0030] like Figure 4 As shown, the annular rotor 2 is nested inside the stator. A water-lubricated bearing 4 is installed in the gap between the stator and the rotor. This bearing system introduces surrounding seawater into the gap, forming a water film that supports the rotor to rotate with low friction while carrying away the heat generated by the generator.

[0031] More specifically, such as Figure 3 and Figure 4 As shown, an annular groove is formed on the inner circumferential surface of the annular stator 1. An annular rotor 2 is embedded in the annular groove through a water-lubricated bearing 4. Multiple blades 3 are evenly distributed and fixed on the inner circumferential surface of the annular rotor 2. The outer end of each blade 3 is fixed on the inner circumferential surface of the annular rotor 2, and the inner end extends towards the center and extends to a position close to the center of the annular stator 1 and the annular rotor 2, so that a small-diameter, directly axially penetrating central opening flow channel 5 is formed between the inner ends of each blade 3 as a flow channel.

[0032] The blade 3 adopts a modular, independently mounted structure. Each blade 3 has a mounting flange at its root, which is rigidly and detachably connected to the inner wall of the annular rotor 2 by fasteners. The fasteners are high-strength, corrosion-resistant bolts, with the bolt heads recessed into the countersunk holes of the mounting flanges to maintain the flatness of the flow channel surface.

[0033] The annular rotor 2 has an array of permanent magnets arranged at uniform intervals along the circumference embedded inside its annular wall. Each permanent magnet constitutes the mounting and bearing base of the outer end of the blade 3.

[0034] like Figure 3 As shown, the blade 3 specifically includes a blade body 301, a mounting flange 302, and a streamlined transition section 303. The mounting flange 302 is fixedly connected to the corresponding permanent magnet in the permanent magnet array on the inner circumference of the annular rotor 2. The mounting flange 302 of the blade 3 has an arc-shaped contact surface that matches the curvature of the inner wall of the annular rotor 2. The root of the blade body 301 is fixedly connected to the mounting flange 302 via the streamlined transition section 303. In this way, a streamlined transition section 303 is provided between the airfoil of the blade body 301 and the mounting flange 302 to reduce stress concentration at the root and water flow disturbance.

[0035] The annular rotor 2 and the annular stator 1 form a gearless direct-drive permanent magnet generator structure. The water flow impacts the blades 3, driving the annular rotor 2 to rotate and directly cutting the magnetic field lines to generate electrical energy.

[0036] The airfoil section of blade 3 is symmetrically designed along the central axis, which enables the device to capture energy equally in both forward and reverse currents without the need for a pitch control mechanism.

[0037] The annular stator 1 has several standardized mounting holes or slots on its two end faces or outer circumference, serving as mounting interfaces 6 for connection to seabed pile foundations, floating platforms, or fairing structures. The mounting interfaces 6 can be located on the outer groove of the stator.

[0038] In specific implementation, the blade mounting structure is the core embodiment of this invention. For example... Figure 3 and Figure 5 As shown, the device includes multiple blades 3, such as 5 or 7 blades as illustrated.

[0039] Blade construction: Each blade 3 consists of a blade body 301 and a mounting flange 302 at the root. The blade body 301 adopts a two-way symmetrical airfoil design, such as the S-shaped or symmetrical isotropic airfoil shown in the figure. This means that regardless of whether the tidal current flows from the front or the back, the blade can generate lift torque in the same direction to drive the rotor to rotate, thus adapting to the ebb and flow of the tide without the need for a complex pitch system.

[0040] Connection method: The bottom of the mounting flange 302 is curved, fitting snugly against the inner cylindrical surface of the annular rotor 2. Countersunk bolt holes are provided on the flange. High-strength stainless steel bolts pass through the flange and are screwed into the threaded holes on the inner wall of the rotor to securely lock the blades.

[0041] Stress optimization: A streamlined transition section 303, i.e., the arc transition seen in the figure, is provided at the connection between the blade body 301 and the mounting flange 302. This design not only reduces the separation vortex of water flow at the root, but also effectively disperses the huge bending moment borne by the blade root, preventing fatigue fracture.

[0042] Working principle: When the water flows through the device, it passes directly through the central open flow channel 5. The fluid flowing over the blade surface generates lift, and the component of this lift in the circumferential tangential direction forms torque, driving the annular rotor 2 to rotate relative to the annular stator 1. The magnetic field of the permanent magnets on the rotor cuts the stator coils, inducing alternating current, which is output through the cable.

[0043] Maintenance process: If a blade is found to be damaged, simply rotate the rotor to the appropriate position, remove the fixing bolts on the blade flange, and the damaged blade can be removed and replaced with a new spare part. The entire process does not involve disassembling the generator stator and rotor air gap, nor does it involve disassembling the shaft system, greatly simplifying the operation and maintenance process.

[0044] The device of this invention adopts a permanent magnet direct-drive generator structure with an inner rotor and an outer stator. The blades are rigidly connected to the inner rotor via modular flanges, and the blades are arranged symmetrically along the rotor's radial direction, enabling bidirectional capture of reciprocating tidal energy. The through-flow annular channel design allows water flow to pass through the device's central axis, reducing flow channel blockage rate and minimizing wake disturbance and energy loss compared to traditional axial flow structures. The modular connection between the blades and the rotor uses a combination of high-strength stainless steel flanges and pre-tightened bolts to ensure connection reliability under high impact loads, and individual blades can be independently disassembled and maintained. The outer stator is fixed to the seabed foundation via support arms, and water-lubricated bearings are used between the inner and outer rotors to achieve low-friction rotation.

[0045] As can be seen from the implementation, the present invention has a compact structural design and uniform impeller force, which can effectively convert tidal kinetic energy into electrical energy. Compared with traditional paddle-type devices, the power generation efficiency is significantly improved, and it is suitable for medium and low tidal energy development scenarios such as coastal areas, straits and estuaries.

Claims

1. A centrally open annular tidal current power generation device, characterized in that, include: The annular stator (1) is annular and has stator windings inside, and has an installation interface (6) on the outer wall for fixing to an external foundation. The annular rotor (2) is arranged in annular shape and coaxially inside the annular stator (1), and the annular interior is provided with a permanent magnet array that cooperates with the stator winding. A water-lubricated bearing (4) is disposed between the annular stator (1) and the annular rotor (2) to support the annular rotor (2) to rotate relative to the annular stator (1); Multiple blades (3) are evenly distributed radially along the circumference and fixed on the inner wall of the annular rotor (2); wherein, a flow channel without a central axis is formed in the center of the device, and multiple blades (3) guide the flow in the flow channel.

2. The annular tidal current power generation device with a central opening according to claim 1, characterized in that: The annular stator (1) has an annular groove on its inner circumferential surface. The annular rotor (2) is fitted into the annular groove by a water-lubricated bearing (4). Multiple blades (3) are evenly and uniformly arranged on the inner circumferential surface of the annular rotor (2). The outer end of each blade (3) is fixed on the inner circumferential surface of the annular rotor (2), and the inner end extends towards the center and extends to a position close to the center of the annular stator (1) and the annular rotor (2), so that an axially through central opening flow channel (5) is formed between the inner ends of each blade (3) as a flow channel.

3. The annular tidal current power generation device with a central opening according to claim 1, characterized in that: The blade (3) adopts a modular independent installation structure. Each blade (3) has an installation flange at its root and is rigidly connected to the inner wall of the annular rotor (2) by fasteners.

4. A centrally open annular tidal current power generation device according to claim 1, characterized in that: The permanent magnet array is a permanent magnet array consisting of multiple permanent magnets arranged at uniform intervals along the circumference, and each permanent magnet constitutes the mounting and bearing base of the outer end of the blade (3).

5. A centrally open annular tidal current power generation device according to claim 1 or 4, characterized in that: The blade (3) specifically includes a blade body (301), a mounting flange (302) and a streamlined transition section (303). The mounting flange (302) is fixedly connected to the corresponding permanent magnet in the permanent magnet array on the inner circumference of the annular rotor (2). The mounting flange (302) of the blade (3) has an arc-shaped contact surface that matches the curvature of the inner wall of the annular rotor (2). The root of the blade body (301) is fixedly connected to the mounting flange (302) via the streamlined transition section (303).

6. A centrally open annular tidal current power generation device according to claim 1, characterized in that: The annular rotor (2) and the annular stator (1) form a gearless direct-drive permanent magnet generator structure. The water flow impacts the blades (3) and drives the annular rotor (2) to rotate, directly cutting the magnetic field lines to generate electrical energy.

7. A centrally open annular tidal current power generation device according to claim 1, characterized in that: The airfoil section of the blade (3) is symmetrically designed along the central axis, which enables the device to capture energy equally in both forward and reverse currents without the need for a pitch mechanism.

8. A centrally open annular tidal current power generation device according to claim 1, characterized in that: The annular stator (1) has several standardized mounting holes or slots on its two end faces or outer circumference as mounting interfaces (6) for connecting with seabed pile foundations, floating platforms or hood structures.

Images