Permanent magnets for generator rotors, rotors, generators, and wind turbines
By adopting an asymmetrical permanent magnet design, the magnet shape of the wind turbine has been optimized, solving the problems of insufficient efficiency and durability in existing technologies, and achieving cost reduction and performance improvement.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SIEMENS GAMESA RENEWABLE ENERGY AS
- Filing Date
- 2025-01-06
- Publication Date
- 2026-05-26
AI Technical Summary
In the existing technology, the permanent magnet design of wind turbines is inefficient and lacks durability, and has high manufacturing costs. In particular, the use of magnet materials in large wind turbines has not been optimized.
The permanent magnet design employs an asymmetrical shape, including a tilted surface and a central surface, with the center point of the central surface offset from the axis of rotation. This optimizes the magnet's volume torque and demagnetization resistance, and the magnet shape is further optimized through finite element analysis to reduce material waste.
It improves the efficiency and durability of the generator, reduces manufacturing costs, optimizes the use of expensive magnet materials, and enhances cooling performance and vibration regulation capabilities.
Smart Images
Figure CN224289420U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to a permanent magnet for a rotor of a wind turbine, a rotor, a wind turbine, and a method for forming a permanent magnet for a rotor of a generator. Background Technology
[0002] Figure 5 The diagram illustrates a radial cross-section of a rotor segment of a generator according to the prior art. Wind turbine generators typically employ permanent magnets in a magnet module that is geometrically symmetrical in the circumferential direction about a radial centerline / plane. Direct-drive (DD) wind turbines employ permanent magnet generators with permanent magnets mounted on the upper surface of the outer rotor. Figure 5 In this configuration, numerous surfaces with typical permanent magnet shapes are mounted within the rotor. Figure 5 The magnet's outline or shape is a flat rectangle on the left side. Figure 5 The outline or shape of the intermediate magnet is an arc-shaped magnet, and... Figure 5 The magnet's outline or shape on the right side is "bread loaf" shaped. In all these cases, the permanent magnet is symmetrically formed about the radial center along a straight line / plane (i.e., circumferentially symmetrical).
[0003] Figure 6 The diagram illustrates a radial cross-section of a rotor segment of a generator according to the prior art. In the radial interior of the rotor, a stator 170 is arranged with an air gap 240 between the rotor and the stator 170. The rotor includes a plurality of permanent magnets 100. Each permanent magnet 100 is housed within a magnet cover plate 230, forming a magnet module. In the magnet module, the permanent magnet 100 is bonded to a base plate 210. The cover plate 230 is located on the permanent magnet 100 and welded to the base plate 210. The magnet module is then mounted to the rotor body 120 within a rotating rotor housing using a T-shaped bracket 220 of the rotor body 120, the T-shaped bracket 220 engaging a complementary portion of the base plate 210. A straight line L0 passing through the center of the base plate 210 of the permanent magnet 100 and the rotor's axis of rotation 80 define a mirror surface, with the permanent magnet 100 symmetrically shaped about the mirror surface. Utility Model Content
[0004] There may be a need for permanent magnets for wind turbine rotors, rotors, wind turbines, and methods for forming permanent magnets for generator rotors that can increase the efficiency and / or durability of generators, while reducing their manufacturing costs. This need can be met by the subject matter according to the independent claims. The present invention has been further developed as set forth in the dependent claims.
[0005] According to a first aspect of the present invention, a permanent magnet for a rotor of a generator is provided. The permanent magnet includes a mounting surface configured to be mounted to a rotor body; and an end surface disposed on a side opposite to the mounting surface, the end surface including two inclined surfaces and a central surface between the inclined surfaces. One or both of the two inclined surfaces and / or the central surface can be substantially flat planes, wherein the edges between the central surface and the respective inclined surfaces can be rounded. In a cross-section of the permanent magnet perpendicular to the axis of rotation of the rotor, the center point of the central surface is shifted from the straight line connecting the center point of the mounting surface and the axis of rotation in the direction of rotation or the opposite direction of rotation of the rotor. This straight line can instead be defined as a normal passing through the center point of the mounting surface.
[0006] In this embodiment, the permanent magnet has a height greater than 10 mm, preferably between 15 and 30 mm; and / or the mounting surface has a circumference greater than 50 mm, preferably between 80 mm and 150 mm. Preferably, the height can be measured along the radial direction of a suitable rotor.
[0007] According to a second aspect of the present invention, a wind turbine is provided comprising a generator having a rotor, the rotor including a plurality of permanent magnets. The rotor is driven by wind energy in a rotational direction about a rotation axis. The center point of the central surface is displaced from the straight line connecting the center point of the mounting surface and the rotation axis in either the rotational or reverse rotational direction of the rotor. This straight line can alternatively be defined as a normal passing through the center point of the mounting surface.
[0008] In one embodiment, the end surface is exposed to the stator of the wind turbine's generator. The stator includes a plurality of slots, with at least one stator coil arranged in a slot, wherein each permanent magnet extends over at least two slots; or the stator includes a concentrated winding topology in which the number of slots per pole per phase (or "number of slots / pole / phase") is fractional, and the permanent magnet extends over at least one slot. The stator can be arranged radially inward or radially outward from the rotor.
[0009] In one embodiment, multiple permanent magnets are mounted to the cylindrical rotor body mounting surface of the rotor body via a mounting surface having a diameter greater than 2000 mm, preferably greater than 3000 mm.
[0010] According to a third aspect of the present invention, a method for forming a permanent magnet for a generator rotor is provided. The method includes providing a mounting surface of the permanent magnet and providing an end surface disposed on a side opposite to the mounting surface, the mounting surface being configured to be mounted to a rotor body of the generator; the end surface includes two inclined surfaces and a central surface between the inclined surfaces. In a cross-section of the permanent magnet perpendicular to the rotor's axis of rotation, the center point of the central surface is displaced from the straight line connecting the center point of the mounting surface and the axis of rotation in either the direction of rotor rotation or the opposite direction of rotation.
[0011] In an embodiment, the shift amount is determined as the torque (or "torque / total permanent magnet volume") used to optimize each full permanent magnet volume, and / or to improve demagnetization resistance, and / or to reduce force pulsation harmonics. Optimization may target either increasing the torque for the same magnet volume or decreasing the magnet volume for the same torque.
[0012] According to a fourth aspect of the present invention, a rotor for a generator of a wind turbine is provided. The rotor is driven by wind energy in a predetermined direction of rotation about a rotation axis. The rotor includes a plurality of permanent magnets, each having a mounting surface, wherein the permanent magnet is mounted to the rotor body of the rotor via the mounting surface. Each permanent magnet has a cross-section perpendicular to the rotation axis of the rotor, wherein a straight line is defined either as intersecting the rotation axis and the center point of the mounting surface, or as a normal passing through the center point of the mounting surface, the straight line dividing the cross-section of each permanent magnet into a leading portion and a trailing portion relative to the direction of rotation about the rotation axis. At least for most of the plurality of permanent magnets, preferably for all of the plurality of permanent magnets, the area of the leading portion is less than or greater than the area of the trailing portion. Preferably, the condition that the area of the leading portion is less than or greater than the area of the trailing portion applies to all cross-sections of the permanent magnet. Although the context of the fourth aspect specifies that the area of the leading portion is less than or greater than the area of the trailing portion, it is clear that such a permanent magnet will also have a volume of the leading body portion that is less than or greater than the volume of the trailing body portion. The guiding body portion and the trailing body portion are divided by a plane defined by the projection of the aforementioned straight line along the axis of rotation.
[0013] In an embodiment, the rotor includes at least one of the following features: each permanent magnet has a height greater than 10 mm, preferably between 15 and 30 mm; the mounting surface has a circumferential length greater than 50 mm, preferably between 80 mm and 150 mm; a plurality of permanent magnets are mounted on a cylindrical rotor body mounting surface of the rotor body, the rotor body mounting surface having a diameter greater than 2000 mm, preferably greater than 3000 mm.
[0014] In the context of this invention, the term "circumferential length" refers to the length of the permanent magnet along the circumferential direction of the rotor.
[0015] In an embodiment, the difference between the area of the guiding portion and the area of the trailing portion is determined as the torque used to optimize each entire permanent magnet volume, and / or to improve demagnetization resistance, and / or to reduce force pulsation harmonics. The optimization may target either increasing the torque for the same magnet volume or decreasing the magnet volume for the same torque.
[0016] In one embodiment, each permanent magnet has a guide body portion with a volume smaller than or larger than that of the trailing body portion, wherein the guide body portion and the trailing body portion are divided by a plane defined by a projection of a straight line along the axis of rotation.
[0017] In an embodiment, each permanent magnet has a depth D along a rotation axis that coincides with the Cartesian coordinate x, wherein the integral of the guide portion along depth D... The integral is less than or greater than the tail portion along depth D. This makes either ; or .
[0018] Here, the integral of the guiding portion corresponds to the volume of the guiding body portion, and the integral of the trailing portion corresponds to the volume of the trailing body portion. Therefore, the volume of the guiding body portion is either less than or greater than the volume of the trailing body portion.
[0019] In one embodiment, each permanent magnet includes an end surface that exposes to the stator of the generator. The stator includes a plurality of slots, with at least one stator coil arranged in a slot, wherein each permanent magnet extends over at least two slots; or the stator includes a concentrated winding topology in which the number of slots per pole per phase is fractional, and the magnet extends over at least one slot. The stator can be arranged radially inward or radially outward from the rotor.
[0020] In existing wind turbine generators, peak currents significantly higher than rated values can be generated in the event of a potential fault such as a short circuit in the stator windings, connecting cables, or converter. The stator magnetomotive force (mmf) obtained in existing permanent magnets can drive the magnet operating point beyond its normal operation in the linear region of the second quadrant of the BH characteristic, and potentially beyond the characteristic "knee" (whose location is temperature-dependent). This can lead to irreversible demagnetization of the permanent magnet and performance loss once the fault is cleared. To prevent demagnetization, in the prior art, the radial thickness of the magnet is often increased symmetrically. However, due to the angular relationship between the rotor magnet and the stator field, this invention does not use a symmetrical shape of the permanent magnet, which has advantages in optimizing the use of magnet material by increasing the magnet thickness only at specific locations, and does not require symmetry. This is particularly advantageous in large wind turbines, which operate primarily in forward power generation mode. Advantageously, in this invention, the use of an asymmetrical magnet profile optimizes the distribution of expensive magnet material within the permanent magnet.
[0021] Considering the above operational requirements, limiting the design to the generally accepted practice of symmetrical magnets may not represent the optimal use / arrangement of very expensive magnet materials (the required rare-earth permanent magnet materials are by far the most expensive materials used in generators, and although their content is low relative to the total generator volume / mass, they still represent a significant proportion of the overall material cost). This invention optimizes the distribution of expensive magnet materials within the permanent magnets, particularly in forward power generation mode. This advantage is especially significant for large wind turbines due to the particularly high size and thus material savings.
[0022] For example, the availability of finite element models and powerful computing systems (where the magnet shape is to be freely controlled / constrained) allows for optimization of the magnet shape without the constraint that the magnet is symmetrical, and the torque per magnet volume (or "torque / magnet volume") can be further maximized (either by increasing the torque for the same magnet volume, or by decreasing the magnet volume for the same torque, or by improving the demagnetization resistance).
[0023] As a result, the convention that magnets must be symmetrical has been removed. Design flexibility has increased, allowing expensive magnet materials to be placed where they are most effective. Magnet materials can be removed from areas where they would not contribute to performance, taking into account operation within limited ranges (a single quadrant of the power-speed plane, a limited range of current angles). Magnet thickness can be increased in areas where demagnetization is required to resist short circuits or fault conditions. Radial forces acting on the magnet module can be increased, and vibration or tone can be adjusted. Cooling effectiveness can be improved due to the larger air gap between the asymmetric magnet and the stator.
[0024] It should be noted that embodiments of this utility model have been described with reference to different subject matter. In particular, some embodiments have been described with reference to device type claims, while others have been described with reference to method type claims. However, those skilled in the art will infer from the above and below description that, unless otherwise stated, in addition to any combination of features belonging to one type of subject matter, there are also any combinations of features relating to different subject matter, particularly any combinations of features between device type claims and method type claims, which are considered to be disclosed with this application. Attached Figure Description
[0025] The foregoing limitations and other aspects of the present invention will become apparent from the examples of the embodiments described below, and will be explained with reference to the examples of the embodiments. The present invention will be described in more detail below with reference to the examples of the embodiments, but the present invention is not limited to the examples of the embodiments.
[0026] Figure 1 The diagram illustrates a wind turbine and its different components;
[0027] Figure 2 The diagram illustrates a radial cross-section of a rotor segment of a generator according to the first embodiment;
[0028] Figure 3 The diagram illustrates a radial cross-section of a rotor segment of a generator according to the second embodiment;
[0029] Figure 4 The diagram illustrates the different operating modes of a wind turbine;
[0030] Figure 5 The diagram illustrates the radial cross-section of a rotor segment of a generator according to the prior art; and
[0031] Figure 6 The diagram illustrates the radial cross-section of a rotor segment of a generator according to the prior art. Detailed Implementation
[0032] The illustrations in the accompanying drawings are schematic. It should be noted that similar or identical elements are given the same reference numerals in different drawings.
[0033] Figure 1 The diagram illustrates a wind turbine 1. The wind turbine 1 includes a nacelle 3 and a tower 2. The nacelle 3 is mounted on top of the tower 2. The nacelle 3 is rotatably mounted relative to the tower 2 by means of a yaw bearing. The axis of rotation of the nacelle 3 relative to the tower 2 is referred to as the yaw axis 9.
[0034] The wind turbine 1 also includes a rotor hub 4 with three rotor blades 6. Figure 1 The image depicts two of the three rotor blades 6. Each blade 6 is configured to vary the pitch by a pitch angle around the pitch axis of the blade 6. The rotor hub 4 is rotatably mounted relative to the nacelle 3 about the rotation axis 8 (rotor axis) by means of the main bearing 7.
[0035] The wind turbine 1 further includes a generator 5. The generator 5, in turn, includes a rotor connecting the generator 5 to a rotor hub 4. If the rotor hub 4 is directly connected to the generator 5, the wind turbine 1 is referred to as a gearless direct-drive wind turbine. This type of generator 5 is referred to as a direct-drive generator 5. Alternatively, the rotor hub 4 can also be connected to the generator 5 via a gearbox. This type of wind turbine 1 is referred to as a geared wind turbine. This invention applies to both types of wind turbines 1.
[0036] The generator 5 is housed within the nacelle 3. The generator 5 is arranged and configured to convert the rotational energy from the rotor hub 4 into electrical energy in the form of alternating current.
[0037] Figure 2 The diagram illustrates a radial cross-section of a rotor segment of the generator 5 according to the first embodiment. The rotor includes a plurality of permanent magnets 10, which are mounted to a cylindrical rotor body mounting surface 20 of the rotor body 12 via mounting surfaces 11. The diameter d of the rotor body mounting surface 20 can be at least 2000 mm, preferably greater than 3000 mm. The permanent magnets 10 can have a height h greater than 10 mm, preferably between 15 and 30 mm. The mounting surface 11 can have a circumferential length l greater than 50 mm, preferably between 80 and 150 mm.
[0038] The permanent magnet 10 includes a mounting surface 11 and an end surface 13. The mounting surface 11 is configured to be mounted to the rotor body 12, and the end surface 13 is disposed on the side opposite to the mounting surface 11. The end surface 13 includes two inclined surfaces 14, 15 and a central surface 16 between the inclined surfaces 14, 15. One or two of the inclined surfaces 14, 15 and / or the central surface 16 can be substantially flat planes. The edges between the central surface 16 and the corresponding inclined surfaces 14, 15 can be rounded.
[0039] In the cross-section of the permanent magnet 10 perpendicular to the rotation axis 8 of the rotor, the center point C16 of the central surface 16 is displaced from the straight line L connecting the center point C11 of the mounting surface 11 and the rotation axis 8 in the rotation direction ω or the opposite rotation direction of the rotor. The straight line L can be alternatively defined as the normal passing through the center point C11 of the mounting surface 11.
[0040] In an embodiment, Figure 1 The wind turbine 1 includes having Figure 2 The generator 5 has a rotor, which includes multiple permanent magnets 10. The rotor is driven by wind energy in the direction of rotation ω around the axis of rotation 8. The center point C16 of the central surface 16 is shifted from the center point C11 of the mounting surface 11 and the straight line L connecting the axis of rotation 8 in the direction of rotation ω or the opposite direction of rotation (depending on operating requirements).
[0041] like Figure 2 As shown in the diagram, the end surface 13 is exposed to the stator 17 of the generator 5 of the wind turbine 1. An air gap 24 is arranged radially inward of the rotor between the stator 17 and the rotor. However, the present invention is also applicable in a modified embodiment where the stator 17 is arranged radially outward of the rotor. The stator 17 includes a plurality of slots 18, with at least one stator coil 19 arranged at each slot 18, wherein each permanent magnet 10 extends over at least two slots 18. In the case where the stator 17 includes a concentrated winding topology, the number of slots per pole per phase in the concentrated winding topology is fractional, and the permanent magnet 10 extends over at least one slot.
[0042] about Figure 2In one embodiment, a method for forming a permanent magnet 10 for a rotor of a generator 5 (e.g., using computer-aided design (CAD), such as finite element analysis) can include the following steps: providing a mounting surface 11 for the permanent magnet 10, wherein the mounting surface 11 is configured to be mounted to a rotor body 12 of the generator 5; and providing an end surface 13, disposed on a side opposite to the mounting surface 11, wherein the end surface 13 includes two inclined surfaces 14, 15 and a central surface 16 between the inclined surfaces 14, 15. In a cross-section of the permanent magnet 10 perpendicular to the axis of rotation 8 of the rotor, the center point C16 of the central surface 16 is displaced from the straight line L connecting the center point C11 of the mounting surface 11 and the axis of rotation 8 in the direction of rotation ω or the opposite direction of rotation of the rotor. The straight line L can instead be defined as a normal passing through the center point C11 of the mounting surface 11. The amount of displacement can be determined as a torque for optimizing each entire permanent magnet volume and / or for improving demagnetization resistance and / or for reducing force pulsation harmonics. Optimization can either aim to increase torque for the same magnet volume or to decrease magnet volume for the same torque.
[0043] In the embodiment, an initial symmetrical profile can be used, wherein the central surface 16 and the inclined surfaces 14, 15 are initially formed symmetrically with respect to the straight line L. In another forming step, material can be removed from one of the inclined surfaces 14 and 15, and the same amount of material can be added to the other of the inclined surfaces 14 and 15.
[0044] On the one hand, the material removed from one of the inclined surfaces 14 and 15, taking into account the current angle and the relationship between the rotor and stator fields during typical operation, can lead to a reduction in magnet volume / mass without significantly affecting overall performance. On the other hand, the magnet thickness / height h at the other of the inclined surfaces 14 and 15 can be increased simultaneously, wherein the overall volume of the permanent magnet 10 remains unchanged relative to a reference, while increasing / growing the performance (maximum torque per ampere (or "maximum torque / ampere")) achievable as the magnet material is shifted / biased toward its most effective region (due to the typical phase angle relationship between the rotor and stator fields). The same advantages can be achieved through the second embodiment described below.
[0045] Figure 3The diagram illustrates a radial cross-section of a rotor segment of the generator 5 according to the second embodiment. The rotor is driven by wind energy in a predetermined rotational direction ω about a rotation axis 8. The rotor includes a plurality of permanent magnets 10, each having a mounting surface 11 on which the permanent magnet 10 is mounted to the rotor body 12, particularly to a cylindrical rotor body mounting surface 20 of the rotor body 12. The rotor body mounting surface 20 can have a diameter d greater than 2000 mm, preferably greater than 3000 mm.
[0046] Each permanent magnet 10 has a cross-section perpendicular to the rotation axis 8 of the rotor, wherein a straight line L is defined to intersect the rotation axis 8 and the center point C11 of the mounting surface 11, and the straight line L divides the cross-section of each permanent magnet 10 relative to the rotation direction ω into a leading portion and a trailing portion. Alternatively, the straight line L can be defined as a normal passing through the center point C11 of the mounting surface 11. At least for most of the plurality of permanent magnets 10, preferably for all of the plurality of permanent magnets 10, the area of the leading portion is smaller than or larger than the area of the trailing portion. For example, in Figure 3 In the embodiment where the predetermined rotation direction ω of the rotor is clockwise, the guide portion is in Figure 3 The middle part is positioned on the right side, and the following part is... Figure 3 It is arranged on the left side. Preferably, the condition that the area of the guide portion is less than or greater than the area of the trailing portion applies to all cross-sections of the permanent magnet 10.
[0047] The difference between the area of the guiding portion and the area of the trailing portion is determined as the torque used to optimize each entire permanent magnet volume, and / or to improve demagnetization resistance, and / or to reduce force pulsation harmonics. Optimization can either aim to increase the torque for the same magnet volume or to decrease the magnet volume for the same torque.
[0048] Each permanent magnet 10 can have a height h greater than 10 mm, preferably between 15 and 30 mm. The mounting surface 11 can have a circumferential length l greater than 50 mm, preferably between 80 and 150 mm.
[0049] Figure 3Further illustration shows that each permanent magnet 10 includes an end surface 13 exposed to the stator 17 of the generator 5. The stator 17 has an air gap 24 arranged radially inward of the rotor between the rotor and the stator 17. However, the present invention is also applicable in a modified embodiment where the stator 17 is arranged radially outward of the rotor. The stator 17 includes a plurality of slots 18, with at least one stator coil 19 arranged at each slot 18, wherein each permanent magnet 10 extends over at least two slots 18. In the case where the stator 17 includes a concentrated winding topology, the number of slots per pole per phase in the concentrated winding topology is fractional, and the magnet extends over at least one slot.
[0050] The concept of an asymmetric magnet is not limited to the flat top and linearly inclined shape as in the first embodiment, but can be applied to more complex shapes as in the second embodiment. For example, the shape of the permanent magnet 10 can be defined by a Bézier curve, wherein each side of the permanent magnet 10 can be as shown in the figure. Figure 3 The diagram in the middle is described by independent Bézier curves. A wide range of contours is possible.
[0051] Figure 3 In the second embodiment, the asymmetric shape of the permanent magnet 10 can be achieved through conventional molding, powder alignment, and sintering processes. The asymmetric mesh shape can be achieved using an asymmetric mold cavity to minimize post-molding and polishing processes in order to achieve the final tolerances. No changes are required for the magnetization process.
[0052] Although the second embodiment has a guide portion area smaller or larger than the trailing portion area, it is clear that this permanent magnet 10 will also have a guide body portion volume smaller or larger than the trailing body portion volume. The guide body portion and the trailing body portion are divided by a plane defined by the projection of the aforementioned straight line L along the rotation axis 8.
[0053] In a modified embodiment, each permanent magnet 10 has a depth D along a rotation axis that coincides with a Cartesian coordinate x, wherein the integral of the guide portion along depth D... The integral is less than or greater than the tail portion along depth D. This makes either ; or .
[0054] Here, the integral of the guiding portion corresponds to the volume of the guiding body portion, and the integral of the trailing portion corresponds to the volume of the trailing body portion. Therefore, the volume of the guiding body portion is either less than or greater than the volume of the trailing body portion.
[0055] Figure 4The illustration depicts different operating modes of the wind turbine 1, namely the four quadrants in the torque-velocity plane, including two power generation modes in the forward and reverse directions, and two maneuvering modes in the forward and reverse directions. Some existing generators operate in all four quadrants, such as traction motors for hybrid and electric vehicles, aerospace actuators, and industrial servo drives.
[0056] However, the generator 5 of the large wind turbine 1 can primarily operate in a forward power generation quadrant because the blades 6 of the wind turbine 1 are only allowed to rotate in the power generation direction, thus allowing the wind turbine 1 to operate essentially in a forward power generation mode, where the load torque acts in the opposite direction of rotation, such as... Figure 4 The lower right quadrant highlights (although there may be a few very special cases that are not this case, namely maintenance / assembly procedures, in which generator 5 is temporarily used as a motor to position and hold rotor hub 4 in the required orientation, but in this particular case, full performance and efficiency are not required).
[0057] As a result, the shape of the permanent magnet 10 can be specifically designed for... Figure 4 Asymmetric optimization is performed on the forward power generation mode in the lower right quadrant because the remaining three quadrants are meaningless for large wind turbine 1. In this case, Figure 2 In the view, the center point C16 of the central surface 16 is preferably shifted in the rotation direction ω of the rotor either from the straight line L connecting the center point C11 of the mounting surface 11 and the axis of rotation 8, or from the straight line L defined as the normal passing through the center point C11 of the mounting surface 11.
[0058] exist Figure 3 In the view, at least for most of the plurality of permanent magnets 10, preferably for all of the plurality of permanent magnets 10, the area of the guiding portion in the cross-section is preferably larger than the area of the trailing portion; or, the integral along the depth D of the guiding portion... Preferably, the integral is greater than the integral along the trailing portion of depth D. , making .
[0059] Furthermore, power electronic converters typically control the stator current phase angle relative to the rotor mechanical angle to achieve maximum torque per ampere (and thus efficiency), while also ensuring compliance with voltage limits. At higher speeds, the current is controlled to achieve a "field weakening" potential, or demagnetizing flux to the rotor magnets (by providing d-axis current). The resulting current angle generated during normal operation is typically within a relatively limited range of torque characteristics relative to the current angle.
[0060] The permanent magnet 10 of this invention can, as Figure 6The diagram shows the installation onto the rotor body 12, where a permanent magnet 10 is housed within a magnet cover plate 230, forming a magnet module. In the magnet module, the permanent magnet 10 is bonded to a base plate 210, which may have a thickness of approximately 4-10 mm (preferably ferromagnetic). The cover plate 230 is located on the permanent magnet 10 and is fixed to the base plate 210 by welding, gluing, or other methods to completely encapsulate the permanent magnet 10 and prevent its corrosion. The magnet module is then installed onto the rotor body 12 within a rotating rotor housing, for example, via a T-shaped bracket 220 of the rotor body 12 and / or bolted connections or other methods, the T-shaped bracket 220 engaging a complementary portion of the base plate 210. Radial, circumferential, and tangential movements can be limited by features machined into the rotor body 12.
[0061] The cover plate 230 can be advantageously molded or pressed together with the inner permanent magnet 10 into a compatible asymmetrical shape, and the magnet module can be loaded into the T-shaped bracket 220 with proper orientation using some minor adjustments to the assembly process.
[0062] It should be noted that the term "comprising" does not exclude other elements or steps, and "a" or "an" does not exclude a plural. Furthermore, elements described in connection with different embodiments may be combined. It should also be noted that reference numerals in the claims should not be construed as limiting the scope of the claims.
Claims
1. A permanent magnet (10) for the rotor of a generator (5), characterized in that, The permanent magnet (10) includes: Mounting surface (11), the mounting surface (11) being configured to be mounted to rotor body (12); The end surface (13) is arranged on the side opposite to the mounting surface (11), and the end surface (13) includes two inclined surfaces (14, 15) and a central surface (16) between the inclined surfaces (14, 15). In the cross section of the permanent magnet (10) perpendicular to the rotation axis (8) of the rotor, the center point (C16) of the central surface (16) is shifted from a straight line (L) in the opposite direction of the rotor's rotation (ω), the straight line (L) either connects the center point (C11) of the mounting surface (11) and the rotation axis (8), or is defined as a normal passing through the center point (C11) of the mounting surface (11); The permanent magnet (10) has a height (h) greater than 10 mm, and / or the mounting surface (11) has a circumference length (l) greater than 50 mm.
2. The permanent magnet (10) according to claim 1, characterized in that, The height (h) of the permanent magnet (10) is between 15 and 30 mm.
3. The permanent magnet (10) according to claim 1, characterized in that, The circumferential length (l) of the mounting surface (11) is between 80 mm and 150 mm.
4. A wind turbine (1), characterized in that, The wind turbine (1) includes a generator (5) with a rotor, the rotor including a plurality of permanent magnets (10) according to any one of claims 1 to 3, wherein the rotor is driven by wind energy in a rotational direction (ω) about a rotational axis (8). Wherein, the center point (C16) of the central surface (16) is displaced from the straight line (L) in the opposite direction of the rotor's rotation (ω); Among them, a plurality of permanent magnets (10) are mounted to the cylindrical rotor body mounting surface (20) of the rotor body (12) of the rotor via the mounting surface (11), the rotor body mounting surface (20) having a diameter (d) greater than 2000 mm.
5. The wind turbine (1) according to claim 4, characterized in that, The diameter (d) of the mounting surface (20) of the rotor body is greater than 3000 mm.
6. The wind turbine (1) according to claim 4 or 5, characterized in that, The end surface (13) is exposed to the stator (17) of the generator (5) of the wind turbine (1), the stator (17) comprising a plurality of slots (18), at least one stator coil (19) being arranged in the slot, wherein each permanent magnet (10) extends over at least two slots (18); or The stator (17) includes a concentrated winding topology in which the number of slots per pole per phase is fractional, and the permanent magnet (10) extends over at least one slot.
7. A rotor of a motor (5) for a wind turbine (1), characterized in that, The rotor is driven by wind energy in a predetermined rotation direction (ω) around the rotation axis (8), and the rotor includes a plurality of permanent magnets (10), each of which has a mounting surface (11), wherein the permanent magnets (10) are mounted to the rotor body (12) of the rotor via the mounting surface (11). Each permanent magnet (10) has a cross-section perpendicular to the rotation axis (8) of the rotor; The straight line (L) is either defined as intersecting the center point (C11) of the axis of rotation (8) and the mounting surface (11), or defined as passing through the normal of the center point (C11) of the mounting surface (11), and the straight line (L) divides the cross section of each permanent magnet (10) into a leading portion and a trailing portion relative to the direction of rotation (ω) around the axis of rotation (8); Among them, at least for most of the plurality of permanent magnets (10), the area of the guiding portion is smaller than the area of the trailing portion; The rotor includes at least one of the following features: Each permanent magnet (10) has a height (h) greater than 10 mm; The mounting surface (11) has a circumferential length (l) greater than 50 mm; The plurality of permanent magnets (10) are mounted to the cylindrical rotor body mounting surface (20) of the rotor body (12) of the rotor via the mounting surface (11), the rotor body mounting surface (20) having a diameter (d) greater than 2000 mm.
8. The rotor according to claim 7, characterized in that, For all of the plurality of permanent magnets (10), the area of the guiding portion is smaller than the area of the trailing portion.
9. The rotor according to claim 7, characterized in that, The height (h) of each permanent magnet (10) is between 15 and 30 mm.
10. The rotor according to claim 7, characterized in that, The circumferential length (l) of the mounting surface (11) is between 80 mm and 150 mm.
11. The rotor according to claim 7, characterized in that, The diameter (d) of the mounting surface (20) of the rotor body is greater than 3000 mm.
12. The rotor according to any one of claims 7 to 11, characterized in that, The difference between the area of the guiding portion and the area of the trailing portion is determined to optimize the torque for each entire permanent magnet volume, and / or to improve demagnetization resistance, and / or to reduce force pulsation harmonics.
13. The rotor according to any one of claims 7 to 11, characterized in that, Each permanent magnet (10) has a volume of a guide body portion smaller than that of the trailing body portion, wherein the guide body portion and the trailing body portion are divided by a plane defined by the projection of the straight line (L) along the axis of rotation (8).
14. The rotor according to any one of claims 7 to 11, characterized in that, Each permanent magnet (10) has a depth D along the rotation axis (8), which coincides with the Cartesian coordinate x, wherein the integral of the guide portion along the depth D is... The integral less than the trailing portion along the depth D , making .
15. A generator (5), characterized in that, The generator (5) includes a rotor according to any one of claims 7 to 14, wherein, Each permanent magnet (10) includes an end surface (13) that exposes to the stator (17) of the generator (5), the stator (17) including a plurality of slots (18) at which at least one stator coil (19) is arranged, wherein each permanent magnet (10) extends over at least two slots (18); or The stator (17) includes a concentrated winding topology in which the number of slots per pole per phase is fractional, and the permanent magnet (10) extends over at least one slot.