Hybrid excitation micro-wind power generation device

Abstract

The utility model discloses a kind of hybrid excitation micro-wind power generation devices, including outer rotor and inner stator, outer rotor includes sleeve, wheel hub is installed on the outer wall of sleeve, the end of wheel hub away from sleeve is installed with blade, sleeve includes upper end cover and lower end cover, one layer annular permanent magnet array and multiple layer annular ferromagnetic block array are installed in the inner wall of sleeve, fixed shaft is rotatably connected between upper end cover and lower end cover, inner stator includes first inner stator and multiple second inner stator, first inner stator and second inner stator are fixedly connected on fixed shaft, the size and position of first inner stator are compatible with annular permanent magnet array, the size and position of second inner stator are compatible with annular ferromagnetic block array, fixed shaft between adjacent second inner stator is provided with electric excitation coil, and electric energy transmission circuit is arranged between first inner stator and electric excitation coil. Power is output to electric excitation coil by first inner stator and excitation magnetic field is generated, and stable voltage can be output, and adaptability is stronger.

Description

Technical Field

[0001] This utility model relates to the field of wind turbine technology, specifically a hybrid excitation micro-wind power generation device. Background Technology

[0002] Currently, wind turbines are mainly divided into two categories: horizontal axis and vertical axis. Horizontal axis wind turbines are the mainstream large-scale wind power technology, but they perform poorly in application scenarios with low wind speeds, turbulence, and variable wind directions. Vertical axis wind turbines, due to their unique structure, have shown great potential in developing and utilizing micro-wind resources. They have advantages such as wind direction independence, compact structure, low noise, and potential low starting torque. However, the actual application of existing vertical wind turbines in micro-wind environments still faces a series of severe challenges. The mechanical resistance and friction inside the generator result in high starting torque and low starting performance, making it difficult to start in low-wind speed conditions. Secondly, because the generator operates in micro-wind environments, the rotation speed is low, which is insufficient to generate an effective and stable voltage, and therefore cannot generate effective current for output.

[0003] Chinese patent CN201730753U discloses a five-degree-of-freedom fully suspended vertical axis wind turbine with an external rotor structure. It uses two permanent magnet radial magnetic levitation bearings to achieve rotor suspension in four radial degrees of freedom and one electromagnetic permanent magnet hybrid axial magnetic levitation bearing to achieve rotor suspension in the axial degree of freedom. This not only achieves full rotor suspension, reducing maintenance costs, friction losses, and cut-in wind speed, but also simplifies the structure of the wind turbine magnetic levitation bearing system, reduces energy loss of the magnetic levitation bearing system, and improves energy conversion efficiency.

[0004] However, in the above scheme, the horizontal radial fixation and the use of radial magnetic levitation bearings will reduce the rotational stability of the outer shell, that is, the outer rotor. In a light wind environment, when the rotational speed is unstable, the power generation device will have difficulty generating an effective and stable voltage. Utility Model Content

[0005] To address the shortcomings of existing technologies, this invention provides a hybrid excitation micro-wind power generation device. The device uses the output power of the first inner stator to power the electric excitation coil between the second inner stator and generate an excitation magnetic field. No external excitation power supply is required, and the outer rotor can generate electricity effectively at a low speed. It is also applicable to a wide range of wind speeds.

[0006] To realize the above-mentioned hybrid excitation micro-wind power generation device, this utility model provides the following technical solution: A hybrid excitation micro-wind power generation device includes an outer rotor and an inner stator. The outer rotor includes a sleeve, a hub is installed on the outer wall of the sleeve, and blades are installed at the end of the hub away from the sleeve. The sleeve includes an upper end cover and a lower end cover. A layer of annular permanent magnet array and a multi-layer annular ferromagnetic block array are installed on the inner side wall of the sleeve. A fixed shaft is rotatably connected between the upper end cover and the lower end cover. The inner stator includes a first inner stator and a plurality of second inner stators. The first inner stator and the second inner stators are fixedly connected to the fixed shaft. The size and position of the first inner stator are adapted to the annular permanent magnet array, and the size and position of the second inner stators are adapted to the annular ferromagnetic block array. An electric excitation coil is provided on the fixed shaft between adjacent second inner stators, and an electrical power transmission circuit is provided between the first inner stator and the electric excitation coil.

[0007] Furthermore, an annular permanent magnet array is installed inside the sleeve near the upper end cover, and an annular ferromagnetic block array is installed near the lower end cover. The multi-layer annular ferromagnetic block array is evenly arranged along the axial direction of the sleeve.

[0008] Furthermore, the first inner stator includes a first iron core, and a first toothed groove is formed on the outer circular surface of the first iron core, extending through both ends. A first armature winding is embedded in the first toothed groove. The ratio of the number of toothed grooves to the number of poles and each phase of the annular permanent magnet array is designed as a fractional-slot structure.

[0009] Furthermore, the second inner stator includes a second iron core, and a second toothed groove is formed on the outer circular surface of the second iron core, extending through both ends. A second armature winding is embedded in the second toothed groove, and the upper and lower adjacent second toothed grooves are staggered.

[0010] Furthermore, the bottom center of the upper end cover is provided with a downward protruding first circular groove, and a first mechanical bearing is provided in the first circular groove. The top center of the lower end cover is provided with an upward protruding second circular groove, and a second mechanical bearing is provided in the second circular groove. The sleeve is rotatably connected to the fixed shaft through the first and second mechanical bearings. The top of the first circular groove is provided with an axial repulsive permanent magnet magnetic levitation bearing. The end of the fixed shaft near the upper end cover is magnetically levitated to the upper end cover through the axial repulsive permanent magnet magnetic levitation bearing. The end of the fixed shaft away from the upper end cover passes through and extends downward out of the lower end cover.

[0011] Furthermore, the axial repulsive permanent magnet levitation bearing includes a first flange and a second flange. The second flange is installed at the top of the first circular groove, and the first flange is installed at the top of the fixed shaft near the upper end cover. The dimensions and positions of the first flange and the second flange are matched. Both the opposite end faces of the first flange and the second flange are provided with annular grooves, and axial permanent magnets are provided in both annular grooves.

[0012] Furthermore, the lower section of the fixed shaft, away from the upper cover, adopts a hollow structure design.

[0013] Compared with the prior art, this utility model provides a hybrid excitation micro-wind power generation device, which has the following beneficial effects: 1. This hybrid excitation micro-wind power generation device, by adopting a hybrid excitation structure design, does not require an additional external excitation power supply. At the same time, the first inner stator corresponding to the initial low wind speed annular permanent magnet array can excite and generate electricity, and can also supply power to the electric excitation coil and generate an excitation magnetic field. Under this dual-coordinated design, the power generation speed range of the hybrid excitation micro-wind power generation device can be expanded, so that it can start to generate electricity effectively at a lower speed. It can be applied to a wider wind speed area, outputs a stable voltage, and has stronger adaptability.

[0014] 2. This hybrid excitation micro-wind power generation device designs a fractional-slot structure by using the ratio of the number of slots in the first slot on the outer circle of the first iron core to the number of poles and phases of the permanent magnets in the annular permanent magnet array. The fractional-slot structure changes the periodicity of the magnetic reluctance change between the stator and rotor, which significantly reduces the amplitude of the magnetic reluctance torque (also called cogging torque), making it easier for the outer rotor to start and operate at lower wind speeds. At the same time, the fractional-slot structure effectively suppresses harmonic magnetic fields (especially tooth harmonics), and the torque pulsation generated by these harmonics is also greatly reduced, thus making the operation of the power generation device more stable and quiet.

[0015] 3. The hybrid excitation micro wind power generation device has an inner stator consisting of a first inner stator and multiple second inner stators. It adopts a segmented structure design, which can further reduce eddy current losses between inner stators, thereby reducing heat generation. Secondly, the segmented structure also enhances heat dissipation capacity and achieves a uniform temperature field (preventing local overheating). Moreover, the segmented structure is easier to manufacture, transport, assemble, and maintain than the integral structure. Attached Figure Description

[0016] Figure 1 This is a cross-sectional view of the structure of this utility model; Figure 2 This is a cross-sectional view of the inner stator structure of this utility model; Figure 3 This is a cross-sectional schematic diagram of the external rotor structure of this utility model; Figure 4 This is a schematic diagram of the structure of the electric excitation coil of this utility model; Figure 5 This is a cross-sectional view of the axial repulsion permanent magnet magnetic levitation bearing structure of this utility model.

[0017] In the diagram: 101, upper end cover; 102, lower end cover; 2, outer rotor; 201, sleeve; 202, annular permanent magnet array; 203, annular ferromagnetic block array; 3, fixed shaft; 4, inner stator; 401, first inner stator; 402, second inner stator; 403, first armature winding; 404, second armature winding; 405, electric excitation coil; 406, first tooth slot; 407, second tooth slot; 501, first mechanical bearing; 502, second mechanical bearing; 6, axial repulsive permanent magnet magnetic levitation bearing; 601, first flange; 602, second flange; 603, axial permanent magnet; 701, hub; 702, blade. Detailed Implementation

[0018] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0019] See Figures 1 to 5A hybrid excitation micro-wind power generation device includes an outer rotor 2 and an inner stator 4. The outer rotor 2 includes a sleeve 201, which is cylindrical and made of ferromagnetic material. A hub 701 is fixedly installed on the outer wall of the sleeve 201. A blade 702 is installed at the end of the hub 701 away from the sleeve 201. The sleeve 201 includes an upper end cover 101 and a lower end cover 102, both of which are made of non-ferromagnetic material. The upper end cover 101 and the lower end cover 102 are fixed to the upper and lower ends of the sleeve 201 by fastening bolts. For fixed connection, a layer of annular permanent magnet array 202 and a multi-layer annular ferromagnetic block array 203 are installed on the inner wall of sleeve 201. The annular permanent magnet array 202 and the annular ferromagnetic block array 203 are bonded to the inner wall of sleeve 201 with epoxy resin structural adhesive. The annular permanent magnet array 202 is made of rare earth materials such as neodymium iron boron, and the annular ferromagnetic block array 203 is made of ferromagnetic materials with high magnetic permeability. Both the annular permanent magnet array 202 and the annular ferromagnetic block array 203 adopt a uniform arc-shaped (fan-shaped) structure for better fit. The inner arc surface of the outer rotor sleeve 201 is fixedly assembled. A fixed shaft 3 is rotatably connected between the upper end cover 101 and the lower end cover 102. The fixed shaft 3 has a long cylindrical structure with a stepped external structure from top to bottom. Its interior adopts a hollow, non-penetrating pipe structure design. The inner stator 4 includes a first inner stator 401 and multiple second inner stators 402. The fixed shaft 3 passes through the first inner stator 401 and the second inner stators 402. The annular permanent magnet array 202 surrounds the first inner stator 401. The size and position of the second inner stators 402 are related to the annular permanent magnet array 202. The ferromagnetic block array 203 is adapted to each other, and each layer of the second inner stator 402 is surrounded by a corresponding annular ferromagnetic block array 203. An electric excitation coil 405 is provided between adjacent second inner stators 402. The electric excitation coil 405 is wound and fixed on the outer circumference of the fixed shaft 3. An electric power transmission circuit is provided between the first inner stator 401 and the electric excitation coil 405. The transmission line circuit is connected through the internal hollow pipe of the fixed shaft 3 and is regulated and controlled by the excitation controller. No external excitation power supply is required, which improves the output power stability of the power generation device.

[0020] Preferably, the annular permanent magnet array 202 is installed inside the sleeve 201 near the upper end cover 101, and the annular ferromagnetic block array 203 is installed near the lower end cover 102. The multi-layer annular ferromagnetic block array 203 is evenly arranged along the axial direction of the sleeve 201. Similarly, the first inner stator 401 is surrounded by the annular permanent magnet array 202 and is located on the fixed shaft 3 near the upper end cover 101. The second inner stator 402 is located on the fixed shaft 3 near the lower end cover 102. The interval between the first inner stator 401 and the uppermost second inner stator 402 is greater than the interval between adjacent second inner stators 402. The first inner stator 401 is located at the higher end and is connected to the lower electric excitation coil 405 through the hollow tube of the fixed shaft 3. The second inner stator 402 located below the first inner stator 401 is connected to the electrical equipment by wiring downwards. The whole structure is more reasonable.

[0021] Preferably, the first inner stator 401 includes a first iron core, through which the fixed shaft 3 passes. The first iron core is made of stacked silicon steel sheets. A first toothed groove 406 is formed on the outer circular surface of the first iron core, extending through both ends. The structure of the first toothed groove 406 adopts a standard equal toothed groove structure design. The first armature winding 403 is embedded in the first toothed groove 406. The ratio of the number of toothed grooves of the first toothed groove 406 to the number of poles and each phase of the permanent magnet array 202 is designed as a fractional slot structure. The amplitude of the reluctance torque (also called the cogging torque) is significantly reduced, making it easier for the outer rotor 2 to start in a light breeze.

[0022] Preferably, the second inner stator 402 includes a second iron core, and a second toothed groove 407 extending through both ends is formed on the outer circular surface of the second iron core. A second armature winding 404 is embedded and wound in the second toothed groove 407. The structure of the second toothed groove 407 adopts an unequal toothed groove structure design, which greatly reduces the toothed torque. The staggered design of the upper and lower adjacent second toothed grooves 407 cancels out the toothed torque of each layer of the second inner stator 402, reducing the starting torque. The segmented structure design of the multi-layer second inner stator 402 enhances the heat dissipation capacity and achieves the effect of uniform temperature field.

[0023] Preferably, the bottom center of the upper end cover 101 is provided with a downwardly protruding first circular groove, and a first mechanical bearing 501 is disposed in the first circular groove. The top center of the lower end cover 102 is provided with an upwardly protruding second circular groove, and a second mechanical bearing 502 is disposed in the second circular groove. The sleeve 201 is rotatably connected to the fixed shaft 3 through the first mechanical bearing 501 and the second mechanical bearing 502. The first mechanical bearing 501 and the second mechanical bearing 502 radially fix the sleeve 201, so that the sleeve 201 will not deflect during rotation, thus affecting the sleeve. The outer rotor 2 rotates while the upper and lower ends of the sleeve 201 are simultaneously radially fixed, making the rotation of the outer rotor 2 more balanced and stable. The top of the first circular groove is provided with an axial repulsive permanent magnet levitation bearing 6. The end of the fixed shaft 3 near the upper end cover 101 is connected to the upper end cover 101 through the axial repulsive permanent magnet levitation bearing 6 to achieve magnetic levitation and bear the load, reducing the mechanical friction and wear between the outer rotor 2 and the fixed shaft 3, and reducing the starting wind speed of the entire power generation device. The end of the fixed shaft 3 away from the upper end cover 101 passes through and extends downward to the lower end cover 102, supporting the entire power generation device.

[0024] Preferably, the axial repulsive permanent magnet levitation bearing 6 includes a first flange 601 and a second flange 602. The second flange 602 is installed at the top of the first circular groove, and the first flange 601 is installed at the top of the fixed shaft 3 near the upper end cover 101. The dimensions and positions of the first flange 601 and the second flange 602 are compatible. Both the opposite end faces of the first flange 601 and the second flange 602 are provided with annular grooves. Axial permanent magnets 603 are provided in both annular grooves. The axial permanent magnets 603 are made of rare earth materials such as neodymium iron boron. Both the first flange 601 and the second flange 602 are made of 40cr alloy structural steel. The axial permanent magnets 603 are fixed in the annular grooves of the first flange 601 and the second flange 602 by epoxy resin structural adhesive. The second flange 602 is fixed in the first circular groove by fastening bolts. An installation groove is opened at the top of the fixed shaft 3, and the first flange 601 is fixed in the installation groove by interference fit and fastening bolts.

[0025] Preferably, the lower inner section of the fixed shaft 3 away from the upper end cover 101 adopts a hollow structure design, and the outer middle and lower section adopts a stepped structure to facilitate the installation and fixing of multiple sections of the second inner stator 402. The fixed shaft 3 is made of alloy structural steel such as 40cr, which ensures the structural strength of the fixed shaft 3. At the same time, the hollow structure design facilitates the wiring arrangement of the first armature winding 403, the second armature winding 404 and the excitation coil 405.

[0026] Working principle: The upper cover 101 is connected to the fixed shaft 3 by an axial repulsive permanent magnet levitation bearing 6, which provides axial support for the weight of the outer rotor 2, hub 701 and blade 702. The first mechanical bearing 501 and the second mechanical bearing 502 provide radial limit for the outer rotor 2, reducing the starting torque of the outer rotor 2. The fractional slot structure design further reduces the starting torque and the starting wind speed. The blade 702 is fixedly connected to the outer wall of the sleeve 201 through the hub 701. The wind drives the blade 702 to drive the outer rotor 2 to rotate. The first inner stator 401 corresponding to the annular permanent magnet array 202 is excited to generate electricity. The excitation controller supplies power to the electric excitation coil 405 and generates an excitation magnetic field, which adjusts the stability of the power generation of the second inner stator 402. The second inner stator 402 outputs a stable voltage through the hollow fixed shaft 3.

[0027] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0028] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A hybrid excitation micro-wind power generation device, comprising an outer rotor (2) and an inner stator (4), wherein the outer rotor (2) comprises a sleeve (201), a hub (701) is mounted on the outer wall of the sleeve (201), and a blade (702) is mounted on the end of the hub (701) away from the sleeve (201), and the sleeve (201) comprises an upper end cover (101) and a lower end cover (102), characterized in that: The inner wall of the sleeve (201) is equipped with a layer of annular permanent magnet array (202) and a multi-layer annular ferromagnetic block array (203). A fixed shaft (3) is rotatably connected between the upper end cover (101) and the lower end cover (102). The inner stator (4) includes a first inner stator (401) and a plurality of second inner stators (402). The first inner stator (401) and the second inner stator (402) are fixedly connected to the fixed shaft (3). The size and position of the first inner stator (401) are adapted to the annular permanent magnet array (202). The size and position of the second inner stator (402) are adapted to the annular ferromagnetic block array (203). An electric excitation coil (405) is provided on the fixed shaft (3) between adjacent second inner stators (402). An electric power transmission circuit is provided between the first inner stator (401) and the electric excitation coil (405).

2. The hybrid excitation micro-wind power generation device according to claim 1, characterized in that: The annular permanent magnet array (202) is installed inside the sleeve (201) on the side near the upper end cover (101), and the annular ferromagnetic block array (203) is installed on the side near the lower end cover (102). The multiple layers of the annular ferromagnetic block array (203) are evenly arranged along the axial direction of the sleeve (201).

3. The hybrid excitation micro-wind power generation device according to claim 1, characterized in that: The first inner stator (401) includes a first iron core. A first toothed groove (406) is provided on the outer circular surface of the first iron core, penetrating both ends. A first armature winding (403) is embedded and wound in the first toothed groove (406). The ratio of the number of toothed grooves in the first toothed groove (406) to the number of poles and each phase of the permanent magnet in the annular permanent magnet array (202) is designed as a fractional slot structure.

4. The hybrid excitation micro-wind power generation device according to claim 1, characterized in that: The second inner stator (402) includes a second iron core. A second toothed groove (407) is provided on the outer circular surface of the second iron core, extending through both ends. A second armature winding (404) is embedded and wound in the second toothed groove (407). The upper and lower adjacent second toothed grooves (407) are designed to be staggered.

5. A hybrid excitation micro-wind power generation device according to claim 1, characterized in that: The bottom center of the upper end cover (101) is provided with a downward protruding first circular groove, and a first mechanical bearing (501) is provided in the first circular groove. The top center of the lower end cover (102) is provided with an upward protruding second circular groove, and a second mechanical bearing (502) is provided in the second circular groove. The sleeve (201) is rotatably connected to the fixed shaft (3) through the first mechanical bearing (501) and the second mechanical bearing (502). The top of the first circular groove is provided with an axial repulsive permanent magnet magnetic levitation bearing (6). The end of the fixed shaft (3) near the upper end cover (101) is magnetically levitated to the upper end cover (101) through the axial repulsive permanent magnet magnetic levitation bearing (6). The end of the fixed shaft (3) away from the upper end cover (101) passes through and extends downward out of the lower end cover (102).

6. A hybrid excitation micro-wind power generation device according to claim 5, characterized in that: The axial repulsive permanent magnet levitation bearing (6) includes a first flange (601) and a second flange (602). The second flange (602) is installed at the top of the first circular groove. The first flange (601) is installed in the central circular groove at the top of the fixed shaft (3) near the upper end cover (101). The size and position of the first flange (601) and the second flange (602) are matched. The opposite end faces of the first flange (601) and the second flange (602) are provided with annular slots. Axial permanent magnets (603) are provided in both annular slots.

7. A hybrid excitation micro-wind power generation device according to claim 1, characterized in that: The lower section of the fixed shaft (3) away from the upper end cover (101) adopts a hollow structure design.

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