A magnetic type semi-direct drive permanent magnet wind power generator

Abstract

The application relates to the technical field of wind power generation equipment, in particular to a magnetic gathering type semi-direct drive permanent magnet wind power generator, which comprises a stator assembly and a rotor assembly coaxially arranged on the radially inner side of the stator assembly, and a gap is formed between the stator assembly and the rotor assembly; the rotor assembly comprises a plurality of rotor cores, the side of the rotor core facing the gap is provided with a surface-mounted permanent magnet, the circumferential two sides of the rotor core are respectively provided with radially extending spoke type permanent magnets, the sides of the two spoke type permanent magnets located on the two sides of the same rotor core and facing the rotor core are the same magnetic poles, and an inter-axis magnetic barrier extending along the axial direction is arranged in the rotor core, the inter-axis magnetic barrier is located in the circumferential middle region of the rotor core in the cross section and between the two spoke type permanent magnets located on the two sides of the same rotor core. The surface-mounted permanent magnet and the spoke type permanent magnet can jointly participate in the formation of the gap magnetic field, and the inter-axis magnetic barrier can adjust the inter-axis magnetic circuit, so that the gap magnetic density is improved, the rare earth permanent magnet consumption is reduced, and the power factor is improved.

Description

Technical Field

[0001] This invention relates to the field of wind power generation equipment technology, specifically to a magnetically focused semi-direct drive permanent magnet wind turbine. Background Technology

[0002] Currently, large-scale offshore wind power systems widely adopt the semi-direct-drive permanent magnet synchronous generator (PMSG) technology to balance transmission efficiency and operational reliability. In traditional surface-mounted PMSG motors, achieving high power density output typically relies on the application of large amounts of high-performance neodymium iron boron rare-earth permanent magnet materials. Simultaneously, the lower remanence density of non-rare-earth permanent magnets or low-cost alternatives often fails to meet the basic requirements for air gap magnetic flux density in high-power units, frequently resulting in a decrease in power density. Furthermore, while some unconventional topologies, such as lateral flux or dual-stator motors, possess the potential to increase power density, their complex mechanical structures significantly increase manufacturing and maintenance difficulties, limiting their economic viability. The spoke-type PMSG structure, through tangential magnetization of permanent magnets to form a flux converging path, effectively enhances the main magnetic field strength and reduces the amount of rare-earth materials required for the same output power, and has already been applied in some small and medium-sized wind turbines. However, the aforementioned structures generally exhibit salient pole characteristics with cross-axis inductance greater than direct-axis inductance, resulting in a low power factor and increasing converter capacity requirements and system losses; that is, the existing technology faces a contradiction between high power density, low material cost, and high power factor. Summary of the Invention

[0003] To address the shortcomings of existing technologies, the purpose of this application is to provide a magnetizing semi-direct drive permanent magnet wind turbine generator to alleviate the contradiction between high power density, low material cost, and high power factor.

[0004] The objective of this application can be achieved through the following technical solutions: A magnetizing semi-direct drive permanent magnet wind turbine includes a stator assembly and a rotor assembly. The rotor assembly is coaxially disposed on the radial inner side of the stator assembly, and an air gap is formed between the stator assembly and the rotor assembly. The rotor assembly includes a plurality of rotor cores distributed circumferentially. With any of the rotor cores mentioned above as a reference, a surface-mounted permanent magnet is provided on the side of the rotor core facing the air gap; The rotor core has spoke-type permanent magnets arranged adjacent to each other on both sides of its circumference, and the spoke-type permanent magnets extend radially along the rotor assembly. The two spoke-type permanent magnets located on opposite sides of the same rotor core in the circumferential direction have the same magnetic pole facing the rotor core; The rotor core is provided with a cross-axis magnetic barrier, which extends along the axial direction of the rotor assembly. Within the cross-section of the rotor assembly, the cross-axis magnetic barrier is located in the circumferential middle region of the rotor core and between the two spoke permanent magnets on both sides of the same rotor core.

[0005] Furthermore, the spoke-type permanent magnet is disposed between two adjacent rotor cores; The radial outer end of the spoke-type permanent magnet is disposed adjacent to the circumferential end of the surface-mounted permanent magnet.

[0006] Furthermore, the spoke-type permanent magnet is a long strip-shaped permanent magnet, with its length direction arranged radially along the rotor assembly and its thickness direction arranged tangentially along the rotor assembly.

[0007] Furthermore, within the cross-section of the rotor assembly, the centerline of the cross-axis magnetic barrier coincides with the circumferential centerline between the two spoke-type permanent magnets on either side of the same rotor core.

[0008] Furthermore, the cross-axis magnetic barrier includes a slot that extends through the rotor core along the axial direction of the rotor assembly.

[0009] Furthermore, within the cross-section of the rotor assembly, the cross-axis magnetic barrier includes a plurality of empty slot segments arranged radially spaced along the rotor assembly. Each empty slot segment is an elongated slot extending radially along the rotor assembly, and the circumferential width of each empty slot segment is less than its radial length. A rotor core connecting bridge is retained between two adjacent empty slot segments.

[0010] Furthermore, the empty slot section includes a first empty slot section and a second empty slot section, wherein the second empty slot section is provided on both sides of the first empty slot section, and the second empty slot section is symmetrical about the first empty slot section.

[0011] Furthermore, the first empty slot section tapers in the direction close to the stator assembly.

[0012] Furthermore, the rotor assembly also includes a sector magnetic barrier with a sector slot, the sector magnetic barrier being opened on the side of the rotor core near the air gap and located between the radial outer end of the spoke permanent magnet and the circumferential end of the surface-mount permanent magnet.

[0013] Furthermore, the radial thickness of the surface-mount permanent magnet is less than the tangential thickness of the spoke-type permanent magnet, and half of the circumferential length of the surface-mount permanent magnet is less than the radial length of the spoke-type permanent magnet.

[0014] This invention uses the rotor core as a common structural reference. Surface-mounted permanent magnets are placed on the side of the rotor core facing the air gap, and radially extending spoke-type permanent magnets are arranged adjacent to each other on both circumferential sides of the same rotor core, with the two spoke-type permanent magnets having the same magnetic pole on the side facing the rotor core. Thus, the spoke-type permanent magnets can form a magnetically focused circuit through the rotor core, while the surface-mounted permanent magnets can form supplementary excitation on the air gap side. Both participate in the formation of the air gap side magnetic field, thereby improving the air gap magnetic flux density and power density without excessively relying on increasing the amount of surface-mounted permanent magnets.

[0015] This invention creates a quadrature-axis magnetic barrier within the rotor core, positioning it in the central circumferential region of the core and between two spoke-type permanent magnets on either side of the same rotor core. This establishes a corresponding relationship between the quadrature-axis magnetic barrier and the spoke-type permanent magnets within the same rotor core, enabling localized reluctance adjustment in the quadrature-axis flux passage area. While maintaining the magnetizing effect of the spoke-type permanent magnets, this design helps reduce the tendency for excessive quadrature-axis inductance, improving the power factor and current control margin during power generation. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the structure of a semi-direct drive permanent magnet wind turbine provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of a conventional surface-mounted permanent magnet wind turbine. Figure 3 This is a comparison diagram of the unloaded air gap magnetic flux density waveforms of the embodiment of the present invention and the conventional surface-mount structure; Figure 4 This is a graph showing the variation trends of the direct-axis inductance Ld and the quadrature-axis inductance Lq under different direct-axis and quadrature-axis current conditions according to an embodiment of the present invention. Figure 5 This is a schematic diagram of the magnetic field distribution under rated load conditions according to an embodiment of the present invention; Figure 6 This is a schematic diagram showing the distribution of the direct-axis magnetic circuit and the quadrature-axis magnetic circuit in an embodiment of the present invention. Detailed Implementation

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

[0019] like Figure 1 and Figure 6 As shown, this application discloses a magnetizing semi-direct drive permanent magnet wind turbine, including a stator assembly 1 and a rotor assembly 2; the rotor assembly 2 is coaxially disposed on the radial inner side of the stator assembly 1, and an air gap is formed between the stator assembly 1 and the rotor assembly 2; thus, the magnetizing semi-direct drive permanent magnet wind turbine in this embodiment is an inner rotor structure, wherein the stator assembly 1 is located on the radial outer side of the rotor assembly 2, and the rotor assembly 2 can rotate relative to the stator assembly 1 around the rotor axis.

[0020] In this application, the stator assembly 1 is not improved compared to the prior art. Specifically, the stator assembly 1 includes a stator core 11 and an armature winding 12 disposed on the stator core 11. The stator core 11 includes a stator yoke 13 and a plurality of stator teeth 14 disposed circumferentially spaced apart. A stator slot 15 is formed between adjacent stator teeth 14, and the armature winding 12 is disposed in the stator slot 15.

[0021] In one embodiment, the stator assembly 1 may employ a 20-pole, 144-slot configuration and a double-layer short-pitch distributed winding. Here, 20 poles indicates that the rotor assembly 2 forms 20 magnetic poles circumferentially, i.e., 10 pole pairs; 144 slots indicates that the stator core 11 forms 144 stator slots circumferentially. It should be noted that the 20-pole, 144-slot configuration is merely an implementation parameter for simulation comparison and is not intended to limit the scope of protection of this application. While maintaining the basic spatial relationship between the rotor core 22, surface-mounted permanent magnets 23, spoke permanent magnets 24, and quadrature-axis magnetic barriers 25, stator assembly 1 and rotor assembly 2 can also adopt other pole-slot combinations, such as 20 poles with 132 slots, 24 poles with 216 slots, or 24 poles with 288 slots. Different pole-slot combinations will affect the winding coefficient, air gap magnetic flux density harmonics, cogging torque, back EMF waveform, and quadrature-axis and direct-axis inductance parameters of armature winding 12. Therefore, when using different pole-slot combinations, the number of stator slots, winding form, number of rotor poles, air gap length, and axial length can be re-determined according to the corresponding model.

[0022] Figure 1The magnetic pole arrangement structure of the rotor assembly 2 is also shown; the rotor assembly 2 includes a plurality of rotor cores 22 distributed circumferentially, the plurality of rotor cores 22 being arranged sequentially around the rotation axis of the rotor assembly 2, each rotor core 22 corresponding to a magnetic pole, that is, each rotor core 22 forming an N pole or an S pole, the plurality of rotor cores 22 being mounted on a rotor support 21, the rotor support 21 being used to support and position the plurality of rotor cores 22.

[0023] The rotor core 22 can be formed by stacking magnetically conductive laminations such as silicon steel sheets and electrical steel sheets along the axial direction of the rotor assembly 2. This stacking method can adopt the conventional stacking process of motor rotor cores to meet the requirements of magnetic conductivity and reduce core loss. The rotor support 21 can be made of non-magnetic materials that meet the requirements of rotor mechanical strength, such as austenitic stainless steel or aluminum alloy. The material selection of the rotor support 21 is based on not forming an obvious main magnetic flux bypass and meeting the rotor operating strength requirements.

[0024] Taking any rotor core 22 as a reference, a surface-mounted permanent magnet 23 is provided on the side of the rotor core 22 facing the air gap. In the inner rotor structure of this embodiment, the side of the rotor core 22 facing the air gap is the radial outer side of the rotor core 22. Therefore, the surface-mounted permanent magnet 23 is disposed on the radial outer peripheral surface of the rotor core 22; the radial inner side of the surface-mounted permanent magnet 23 is connected to the radial outer side of the rotor core 22, and the radial outer side of the surface-mounted permanent magnet 23 faces the inner peripheral side of the stator assembly 1.

[0025] In one embodiment, the surface-mount permanent magnet 23 can be an arc-shaped sheet permanent magnet adapted to the outer circular contour of the rotor assembly 2; the surface-mount permanent magnet 23 and the rotor core 22 can be fixed by adhesive bonding, with the adhesive layer disposed between the radial inner side of the surface-mount permanent magnet 23 and the radial outer side of the rotor core 22, so that the surface-mount permanent magnet 23 is stably attached to the side of the rotor core 22 facing the air gap.

[0026] The shape of the surface-mount permanent magnet 23 is not limited to the single arc-shaped profile shown in the attached figure. As long as the surface-mount permanent magnet 23 is disposed on the side of the rotor core 22 facing the air gap and is adapted to the air gap side surface of the rotor core 22, the surface-mount permanent magnet 23 can be a single arc-shaped sheet permanent magnet or it can be composed of multiple arc-shaped sheet permanent magnet units spliced ​​together along the circumference. The surface-mount permanent magnet 23 and the rotor core 22 are not limited to a single bonding method. Under the condition of meeting the rotor mechanical strength and operational reliability, pressure plate limiting, end block limiting or slot limiting structure can also be used.

[0027] The surface-mounted permanent magnet 23 is magnetized radially along the rotor assembly 2, that is, the N pole and S pole of the surface-mounted permanent magnet 23 are distributed radially along the rotor assembly 2; along the circumference of the rotor assembly 2, the surface-mounted permanent magnets 23 corresponding to two adjacent rotor cores 22 are magnetized in opposite directions, thus forming magnetic poles arranged alternately along the circumference.

[0028] The rotor core 22 is provided with spoke-type permanent magnets 24 on both sides of its circumference. The spoke-type permanent magnets 24 are disposed between two adjacent rotor cores 22 and are sandwiched in the area between the two adjacent rotor cores 22. The spoke-type permanent magnets 24 extend radially along the rotor assembly 2, with their inner radial end facing the side where the rotor support 21 is located and their outer radial end facing the side where the air gap is located.

[0029] In one embodiment, the spoke permanent magnet 24 is a long strip-shaped permanent magnet. The length direction of the spoke permanent magnet 24 is arranged radially along the rotor assembly 2, the thickness direction of the spoke permanent magnet 24 is arranged tangentially along the rotor assembly 2, and the axial direction of the spoke permanent magnet 24 is consistent with the axial direction of the rotor assembly 2. Here, tangential refers to the direction corresponding to the circumferential direction within the cross-section of the rotor assembly 2.

[0030] The spoke-type permanent magnet 24 is not limited to an absolutely straight line or a single rectangular cross section. As long as the spoke-type permanent magnet 24 is sandwiched between two adjacent rotor cores 22 and extends radially as a whole along the rotor assembly 2, the spoke-type permanent magnet 24 can be a straight bar permanent magnet, a long bar permanent magnet with chamfered ends, or a combination of multiple permanent magnet units arranged radially in sequence. The spoke-type permanent magnet 24 can be limited by the side walls of two adjacent rotor cores 22 and can be fixed by bonding, end limiting or clamping structures.

[0031] The spoke-type permanent magnets 24 are magnetized tangentially along the rotor assembly 2, that is, the N pole and S pole of the spoke-type permanent magnets 24 are distributed tangentially along the rotor assembly 2; the two spoke-type permanent magnets 24 located on both sides of the same rotor core 22 have the same magnetic pole facing the rotor core 22; that is, for the same rotor core 22, the two spoke-type permanent magnets 24 on both sides of its circumference face the rotor core 22 with the same magnetic pole, so that the two spoke-type permanent magnets 24 and the rotor core 22 form a corresponding magnetic circuit structure.

[0032] Through the aforementioned polarity arrangement, the two spoke-type permanent magnets 24 located on both sides of the same rotor core 22 can form a magnetic concentrating structure using the rotor core 22 as a magnetic conduction path. Specifically, the two spoke-type permanent magnets 24 have the same magnetic poles on the side facing the same rotor core 22, causing their corresponding magnetic flux to tend to distribute towards the side closer to the air gap via the rotor core 22; the surface-mounted permanent magnet 23 is disposed on the side of the rotor core 22 facing the air gap, which can form a supplementary permanent magnet magnetic field on the air gap side. Thus, the surface-mounted permanent magnet 23 and the spoke-type permanent magnet 24 are not arranged independently of each other, but form a permanent magnet arrangement structure near the same rotor core 22 that combines surface excitation on the air gap side with magnetic concentration on the circumferential side.

[0033] The radially outer end of the spoke-type permanent magnet 24 is positioned adjacent to the circumferential end of the surface-mount permanent magnet 23. Specifically, the radially outer end of the spoke-type permanent magnet 24 is located on the side near the air gap and close to the circumferential end region of the adjacent surface-mount permanent magnet 23. Thus, the surface-mount permanent magnet 23 and the spoke-type permanent magnet 24 are arranged in a close proximity relationship on the air gap side of the rotor core 22. The term "close proximity" means that the two are close to each other within the cross-section of the rotor assembly 2 and form a local spatial fit, without requiring direct contact between them.

[0034] The surface-mount permanent magnet 23 has a radial thickness measured along the radial direction of the rotor assembly 2 and a circumferential length measured along the circumference of the rotor assembly 2; the spoke permanent magnet 24 has a tangential thickness measured along the tangential direction of the rotor assembly 2 and a radial length measured along the radial direction of the rotor assembly 2; the radial thickness of the surface-mount permanent magnet 23 is less than the tangential thickness of the spoke permanent magnet 24, and half of the circumferential length of the surface-mount permanent magnet 23 is less than the radial length of the spoke permanent magnet 24.

[0035] By making the radial thickness of the surface-mount permanent magnet 23 smaller than the tangential thickness of the spoke permanent magnet 24, the spoke permanent magnet 24 can form a relatively large permanent magnet cross-section on the circumferential side of the rotor core 22. By making half of the circumferential length of the surface-mount permanent magnet 23 smaller than the radial length of the spoke permanent magnet 24, the surface-mount permanent magnet 23 can be mainly arranged in the local area near the air gap, while the spoke permanent magnet 24 extends radially to the area near the air gap side. This is beneficial for the spoke permanent magnet 24 to undertake the main magnetizing function, and the surface-mount permanent magnet 23 to undertake the air gap side magnetizing function, thereby avoiding the design of the surface-mount permanent magnet 23 as an excessively large air gap side permanent magnet.

[0036] Surface-mounted permanent magnets 23 and spoke-type permanent magnets 24 can be made of neodymium iron boron (NdFeB) permanent magnet material. Under different temperature ratings or demagnetization margin requirements, surface-mounted permanent magnets 23 and spoke-type permanent magnets 24 can use the same or different grades of NdFeB permanent magnet material. The choice of material grade does not change the basic structural relationship of surface-mounted permanent magnets 23 located on the air gap side of rotor core 22, spoke-type permanent magnets 24 located on both circumferential sides of rotor core 22, and quadrature-axis magnetic barriers 25 located on the q-axis magnetic circuit.

[0037] A quadrature-axis magnetic barrier 25 is formed within the rotor core 22, extending axially along the rotor assembly 2. The quadrature-axis magnetic barrier 25 may include a slot penetrating the rotor core 22 along the axial direction of the rotor assembly 2. This slot can be formed by pre-forming slots in the magnetically conductive sheets constituting the rotor core 22 and then stacking them, or it can be formed through subsequent processing.

[0038] Figure 6 The d-axis and q-axis magnetic circuits in this embodiment are shown. (In conjunction with...) Figure 6 It can be seen that the quadrature-axis magnetic barrier 25 is set on the q-axis magnetic path. In other words, under the d-axis and q-axis coordinate definitions in this embodiment, the quadrature-axis magnetic barrier 25 is not set at any position in the rotor core 22, but is set in the region of the rotor core 22 through which the quadrature-axis magnetic flux passes.

[0039] Within the cross-section of rotor assembly 2, the quadrature-axis magnetic barrier 25 is located in the circumferential central region of rotor core 22, and lies between the two spoke-type permanent magnets 24 on either side of the same rotor core 22. Furthermore, the centerline of the quadrature-axis magnetic barrier 25 can coincide with the circumferential centerline between the two spoke-type permanent magnets 24 on either side of the same rotor core 22. Here, the circumferential centerline refers to the midline located between the two spoke-type permanent magnets 24 on either side of the circumferential surface of rotor core 22 within the cross-section of rotor assembly 2.

[0040] In a structure where spoke-type permanent magnets 24 are disposed on both sides of the rotor core 22, a cross-axis magnetic flux path related to the q-axis magnetic circuit is formed inside the rotor core 22. If the cross-axis magnetic flux path is not adjusted, the magnetic focusing structure formed by the spoke-type permanent magnets 24 may simultaneously cause the cross-axis magnetic circuit to have high permeability. In this embodiment, a cross-axis magnetic barrier 25 is disposed on the q-axis magnetic circuit and positioned between two spoke-type permanent magnets 24 on both sides of the same rotor core 22. This allows for local magnetic reluctance adjustment in the area traversed by the q-axis magnetic flux without changing the basic installation position of the spoke-type permanent magnets 24. Thus, the cross-axis magnetic barrier 25 and the spoke-type permanent magnets 24 form a corresponding relationship within the same rotor core 22, which is used to suppress the tendency for the cross-axis inductance to be too large due to a simple magnetic focusing structure.

[0041] In one embodiment, the quadrature-axis magnetic barrier 25 includes a plurality of slotted segments arranged radially spaced along the rotor assembly 2. Each slotted segment is an elongated slot extending radially along the rotor assembly 2, and the circumferential width of each slotted segment is less than its radial length. A rotor core connecting bridge is maintained between two adjacent slotted segments. The rotor core connecting bridge is part of the rotor core 22 and is used to connect the magnetically conductive regions on both sides of adjacent slotted segments to maintain the overall mechanical continuity of the rotor core 22.

[0042] When the quadrature-axis magnetic barrier 25 uses multiple empty slot segments, the rotor core connecting bridges retained between adjacent empty slot segments enable the rotor core 22 to maintain continuous mechanical support in the circumferential central region. Compared to designing the quadrature-axis magnetic barrier 25 as a single long empty slot, the segmented arrangement of multiple empty slot segments can reduce the weakening of the overall strength of the rotor core 22 while forming local magnetic reluctance of the q-axis magnetic circuit.

[0043] The shape of the quadrature-axis magnetic barrier 25 is not limited to a specific slot shape. As long as the quadrature-axis magnetic barrier 25 is opened inside the rotor core 22 and located on the q-axis magnetic circuit, and is located between two spoke-type permanent magnets 24 on both sides of the same rotor core 22 within the cross-section of the rotor assembly 2, the quadrature-axis magnetic barrier 25 can be a single axially penetrating slot or a group of slots composed of multiple slot segments. The multiple slot segments can be arranged radially at intervals, and rotor core connecting bridges are retained between adjacent slot segments.

[0044] Furthermore, such as Figure 6 As shown, the empty slot section includes a first empty slot section 251 and a second empty slot section 252. The first empty slot section 251 is located in the circumferential central region of the rotor core 22, and a second empty slot section 252 is provided on both sides of the first empty slot section 251, symmetrically positioned about the first empty slot section 251. Thus, the cross-axis magnetic barrier 25 forms a slot group structure within the cross-section of the rotor core 22, symmetrically arranged with the first empty slot section 251 as the center and the second empty slot sections 252 on both sides.

[0045] The first empty slot section 251 is located in the circumferential middle region of the rotor core 22, and the second empty slot section 252 is located on both sides of the first empty slot section 251 and is symmetrical about the first empty slot section 251. This allows the quadrature-axis magnetic barrier 25 to form a symmetrical slot group structure within the cross-section of the rotor core 22. This symmetrical slot group structure is beneficial to ensure that the q-axis magnetic circuits on both sides of the same rotor core 22 are subjected to more balanced magnetic resistance adjustment, and to avoid the quadrature-axis magnetic barrier 25 being only biased to one side, resulting in uneven magnetic circuit distribution.

[0046] In one embodiment, the first slot segment 251 tapers towards the stator assembly 1. Since the stator assembly 1 is located radially outward of the rotor assembly 2 in this embodiment, the direction towards the stator assembly 1 is radially outward toward the air gap. The taper of the first slot segment 251 towards the stator assembly 1 means that the portion of the first slot segment 251 near the air gap has a smaller circumferential dimension than the portion away from the air gap, or that the two side boundaries of the first slot segment 251 gradually approach each other in the radially outward direction.

[0047] The contraction form of the first empty slot section 251 can be linear contraction, zigzag contraction, or arc transition contraction, as long as it forms a slot section shape that gradually narrows towards the air gap side. The second empty slot section 252 can be a long and narrow slot, a nearly long and narrow slot, or a slot structure with rounded corners. The specific number, length, width, and spacing of the first empty slot section 251 and the second empty slot section 252 can be adapted to the mechanical strength and electromagnetic performance requirements of the rotor core 22.

[0048] The rotor assembly 2 also includes a sector-shaped magnetic barrier 26, which has a sector-shaped slot. The sector-shaped magnetic barrier 26 is located on the side of the rotor core 22 near the air gap and is situated between the radial outer end of the spoke-type permanent magnet 24 and the circumferential end of the surface-mounted permanent magnet 23. Specifically, the sector-shaped magnetic barrier 26 is disposed near the radial outer end of the spoke-type permanent magnet 24 and adjacent to the circumferential end of the surface-mounted permanent magnet 23.

[0049] The sector-shaped magnetic barrier 26 is spaced apart from the surface-mounted permanent magnet 23, and also spaced apart from the spoke-type permanent magnet 24. In other words, the sector-shaped magnetic barrier 26 is not directly connected to either the surface-mounted permanent magnet 23 or the spoke-type permanent magnet 24, but is instead located in a localized area of ​​the rotor core 22 near the air gap. This arrangement ensures the stability of the surface-mounted permanent magnet 23 and the spoke-type permanent magnet 24 during installation, while simultaneously creating a localized magnetic isolation structure in their adjacent areas.

[0050] Since the radial outer end of the spoke-type permanent magnet 24 is adjacent to the circumferential end of the surface-mount permanent magnet 23, a local end magnetic flux path is easily formed in this region. The fan-shaped magnetic barrier 26 is disposed between the radial outer end of the spoke-type permanent magnet 24 and the circumferential end of the surface-mount permanent magnet 23, and is spaced apart from both the surface-mount permanent magnet 23 and the spoke-type permanent magnet 24, thus forming a local magnetic isolation space in this adjacent region. Therefore, the fan-shaped magnetic barrier 26 can weaken the local magnetic leakage tendency near the radial outer end of the spoke-type permanent magnet 24 and facilitate the distribution of magnetic flux towards the side closer to the air gap.

[0051] The shape of the sector magnetic barrier 26 is not limited to a sector in the standard geometric sense; the sector magnetic barrier 26 can be a sector-shaped slot, an approximately sector-shaped slot, an arc-shaped slot, or an arc-shaped slot with rounded corners. As long as the sector magnetic barrier 26 is located on the side of the rotor core 22 near the air gap and between the radial outer end of the spoke permanent magnet 24 and the circumferential end of the surface-mount permanent magnet 23, it can be used as the equivalent slot shape of the sector magnetic barrier 26 in this embodiment.

[0052] like Figure 2 As shown, the structure of a conventional surface-mounted permanent magnet wind turbine, specifically, is similar to... Figure 2 Compared to the structure shown, in this embodiment, in addition to providing surface-mounted permanent magnets 23 on the side of the rotor core 22 facing the air gap, the rotor assembly 2 also provides spoke-type permanent magnets 24 on both circumferential sides of the rotor core 22, and provides cross-axis magnetic barriers 25 inside the rotor core 22.

[0053] like Figure 3 As shown, this embodiment is similar to Figure 2 A comparison of the no-load air gap magnetic flux density waveforms of conventional surface-mounted permanent magnet wind turbines. The horizontal axis represents mechanical angles, and the vertical axis represents air gap magnetic flux density. Figure 3 It can be seen that, under the same or comparable stator parameters, rotor parameters, and material parameters, the air gap magnetic flux density waveform of this embodiment and the conventional surface-mount structure both exhibit periodic changes. However, the air gap magnetic flux density curve of this embodiment is generally at a higher or similar level within the main magnetic flux density operating range, especially showing a higher magnetic flux density amplitude trend in multiple peak regions. This result indicates that after the surface-mount permanent magnet 23 is disposed on the side of the rotor core 22 facing the air gap, and the spoke permanent magnet 24 is disposed on both circumferential sides of the rotor core 22 and forms a magnetically focused circuit with the rotor core 22, the two can jointly participate in the formation of the air gap side magnetic field, resulting in an improved air gap side magnetic flux density distribution compared to the conventional surface-mount structure.

[0054] Furthermore, by Figure 3 It can also be seen that the air gap magnetic flux density waveform in this embodiment maintains continuous fluctuations within the magnetic pole action region, without significant abrupt changes due to the introduction of the spoke-type permanent magnet 24. This phenomenon indicates that the spoke-type permanent magnet 24 does not independently superimpose a magnetic field onto the air gap side, but rather forms a composite magnetic circuit through the rotor core 22 and the surface-mounted permanent magnet 23, enabling the air gap magnetic flux density to maintain a high amplitude level while preserving a periodic distribution. It should be noted that... Figure 3 This is used to illustrate the trend of air gap magnetic flux density variation in this embodiment compared to the conventional surface-mount structure. The specific magnetic flux density value will vary with the pole slot matching, permanent magnet material, air gap length, rotor core 22 size and armature winding 12 parameters, and should not be construed as a limitation that all models have the same quantitative results.

[0055] Figure 4This diagram illustrates the variation trends of the direct-axis inductance Ld and quadrature-axis inductance Lq of the generator in this embodiment under different direct-axis current Id and quadrature-axis current Iq. Among these, Figure 4 The left side shows the surface where the direct-axis inductance Ld varies with Id and Iq. Figure 4 The right side shows the surface showing the variation of the quadrature-axis inductance Lq with Id and Iq. Figure 4 It can be seen that within the indicated current range, the direct-axis inductance Ld and the quadrature-axis inductance Lq are relatively close. When the current Iq is large, there will be a situation where Ld ≥ Lq, indicating that the quadrature-axis magnetic barrier 25 in this embodiment can effectively reduce the quadrature-axis permeability and balance the quadrature-direct-axis inductance parameters.

[0056] Combination Figure 4 As can be seen from the curved surface on the right, the quadrature-axis inductance Lq is affected by the quadrature-axis magnetic barrier 25 within the indicated operating range. Since the quadrature-axis magnetic barrier 25 is located within the rotor core 22 and on the q-axis magnetic path, the quadrature-axis magnetic flux passing through this region experiences localized magnetic reluctance from the barrier, thereby adjusting the equivalent permeability of the quadrature-axis magnetic path. In other words, the quadrature-axis magnetic barrier 25 is not used as a simple weight-reduction slot, but rather is arranged corresponding to the q-axis magnetic flux path to alter the flow state of the quadrature-axis magnetic flux within the rotor core 22.

[0057] Furthermore, combined Figure 4 As can be understood from the curved surfaces on the left and right sides, this embodiment achieves different magnetic reluctance distributions in the direct-axis and quadrature-axis magnetic circuits by setting surface-mounted permanent magnets 23, spoke-type permanent magnets 24, and quadrature-axis magnetic barriers 25 within the same rotor core 22. When the spoke-type permanent magnets 24 form a magnetically focused circuit with the rotor core 22, the quadrature-axis magnetic barrier 25 is located in the corresponding region of the q-axis magnetic circuit, which can locally constrain the quadrature-axis magnetic flux path; while the direct-axis magnetic circuit is mainly formed by the rotor core 22 and the air gap side magnetic circuit. Thus, this embodiment can adjust the quadrature-axis inductance Lq while maintaining the participation of the magnetically focused structure in the formation of the air gap magnetic field, so that the generator exhibits an inductance change trend that is beneficial to power factor improvement within the shown operating range.

[0058] It should be noted that, Figure 4 This explanation illustrates the influence of the positional correspondence between the quadrature-axis magnetic barrier 25 and the q-axis magnetic circuit on the trends of Ld and Lq, and does not imply that all models have the same inductance values. The specific values ​​of Ld and Lq will vary depending on the pole-slot fit, air gap length, rotor core 22 dimensions, the material and dimensions of the surface-mounted permanent magnet 23 and the spoke permanent magnet 24, the armature winding 12 parameters, and the operating current range.

[0059] Figure 5 This illustration shows the magnetic field line distribution under rated load conditions in this embodiment. Figure 5It can be seen that the magnetic field lines are continuously distributed circumferentially and radially within the rotor core 22, exhibiting different density states in the regions where the surface-mounted permanent magnets 23, spoke-type permanent magnets 24, quadrature-axis magnetic barriers 25, and sector-shaped magnetic barriers 26 are located. Specifically, the spoke-type permanent magnets 24 are located between adjacent rotor cores 22, and their corresponding magnetic flux converges towards the side closer to the air gap through the rotor core 22; the surface-mounted permanent magnets 23 are located on the side of the rotor core 22 facing the air gap, and their corresponding magnetic flux directly participates in the formation of the magnetic field on the air gap side. Therefore, Figure 5 It can intuitively reflect the composite magnetic circuit relationship formed by the surface-mounted permanent magnet 23 and the spoke permanent magnet 24 around the same rotor core 22.

[0060] Furthermore, by Figure 5 It can also be observed that the quadrature-axis magnetic barrier 25 is located within the rotor core 22, between the spoke-type permanent magnets 24 on both sides of the circumference of the same rotor core 22. The region where the quadrature-axis magnetic barrier 25 is located has a blocking or deflecting effect on some of the magnetic flux passing laterally through the rotor core 22, making the magnetic field line distribution in this region different from that in the continuous magnetic core region. The results shown in the figure indicate that the quadrature-axis magnetic barrier 25 is not simply set up as a weight reduction slot or process slot, but is arranged corresponding to the q-axis magnetic circuit to form a local magnetic reluctance adjustment region inside the rotor core 22.

[0061] Simultaneously, a fan-shaped magnetic barrier 26 is positioned between the radially outer end of the spoke-type permanent magnet 24 and the circumferential end of the surface-mounted permanent magnet 23. Combined Figure 5 As can be seen from the magnetic field lines, the fan-shaped magnetic barrier 26 is located in the adjacent region of the two types of permanent magnets. It can change the magnetic flux path in this local area, reduce the tendency for direct short circuits or local leakage of magnetic flux near the radial outer end of the spoke-type permanent magnet 24, and help guide the magnetic flux towards the air gap side. Thus, the fan-shaped magnetic barrier 26, together with the surface-mounted permanent magnet 23, the spoke-type permanent magnet 24, and the quadrature-axis magnetic barrier 25, forms a mutually cooperating rotor magnetic circuit structure.

[0062] It should be noted that, Figure 5 This description is intended to illustrate the relative active areas and magnetic field line distribution trends of each magnetic circuit structure in this embodiment under rated load conditions. It should not be construed as a limitation on specific magnetic flux density values, local saturation levels, or the magnetic field line distribution state under all operating conditions. The specific magnetic field line density will vary with the pole-slot fit, air gap length, rotor core 22 dimensions, surface-mounted permanent magnets 23 and spoke permanent magnets 24 materials and dimensions, armature winding 12 parameters, and load current variations.

[0063] For ease of understanding, in this specification, "radial" refers to the direction from the outer periphery to the rotation axis of rotor assembly 2 or from the outer periphery to the rotation axis; "circumferential" refers to the circumferential direction around the rotation axis of rotor assembly 2; "tangential" refers to the direction corresponding to the circumferential direction within the cross-section of rotor assembly 2; and "axial" refers to the direction extending along the rotation axis of rotor assembly 2.

[0064] In this embodiment, "the side facing the air gap" refers to the radially outer side of the rotor core 22 for the inner rotor structure. Taking any rotor core 22 as a reference, the surface-mounted permanent magnet 23 is located on the radially outer side of the rotor core 22, the spoke permanent magnet 24 is located on both circumferential sides of the rotor core 22, the cross-axis magnetic barrier 25 is located in the circumferential central region inside the rotor core 22, and the fan-shaped magnetic barrier 26 is located in a local region of the rotor core 22 near the air gap.

[0065] In this embodiment, "first empty slot segment 251" and "second empty slot segment 252" are only used to distinguish empty slot segments at different locations in the quadrature-axis magnetic barrier 25, and do not imply that there is necessarily a limiting relationship between them in terms of quantity, size, or importance. The first empty slot segment 251 can be understood as the empty slot segment located in the circumferential center of the rotor core 22, and the second empty slot segment 252 can be understood as the empty slot segments arranged on both sides of the first empty slot segment 251.

[0066] In this embodiment, "between" refers to the area defined by two structures in the circumferential or radial direction, and does not require that it be located at the exact geometric midpoint; "circumferential mid-region" refers to the area located near the middle position between the spoke permanent magnets 24 on both sides of the same rotor core 22 in the circumferential direction; "spacing" means that the solid part of the rotor core 22 or other non-connected area is reserved between the two structures, and does not require a specific numerical spacing.

[0067] The rotor core 22 can be fixed to the rotor bracket 21 by rivets, bolts, pressure plates, positioning keys or circumferential limiting blocks. The above fixing methods are used to achieve circumferential positioning and radial support of the rotor core 22 without changing the basic spatial relationship between the rotor core 22, the surface-mounted permanent magnet 23, the spoke permanent magnet 24 and the quadrature magnetic barrier 25.

[0068] In this embodiment, the rotor core 22, surface-mounted permanent magnet 23, spoke permanent magnet 24, cross-axis magnetic barrier 25, and sector magnetic barrier 26 can be repeatedly arranged along the circumference of the rotor assembly 2. The specific number of each component can be determined according to the number of magnetic poles of the rotor assembly 2, and the specific dimensions of each component can be adapted to the generator's power rating, rotor outer diameter, air gap length, axial length, mechanical strength, and electromagnetic performance requirements.

[0069] Without changing the above-mentioned composite rotor magnetic circuit arrangement, the surface-mounted permanent magnet 23 can adopt a single-block, segmented, or circumferentially spliced ​​structure; the spoke permanent magnet 24 can adopt a straight strip, a long strip with chamfered ends, or a structure formed by combining multiple permanent magnet units; the cross-axis magnetic barrier 25 can adopt a single empty slot or a slot group structure composed of multiple empty slot segments; the fan-shaped magnetic barrier 26 can adopt a fan-shaped empty slot, an approximately fan-shaped empty slot, an arc-shaped empty slot, or an arc-shaped empty slot with rounded corners.

[0070] Similarly, the fixing method between the rotor core 22 and the rotor support 21, the fixing method between the surface-mount permanent magnet 23 and the rotor core 22, the limiting method of the spoke permanent magnet 24 between adjacent rotor cores 22, and the lamination method of the rotor core 22 can all be selected according to the requirements of mechanical strength, assembly process, and operational reliability. For example, the rotor core 22 can be fixed to the rotor support 21 by rivets, bolts, pressure plates, positioning keys, or circumferential limiting blocks; the surface-mount permanent magnet 23 can be set on the rotor core 22 by bonding, pressure plate limiting, end block limiting, or slot limiting.

[0071] In the description of this specification, the references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0072] The foregoing has shown and described the basic principles, main features, and advantages of this application. Those skilled in the art should understand that this application is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this application. Various changes and modifications can be made to this application without departing from the spirit and scope thereof, and all such changes and modifications fall within the scope of the claims of this application.

Claims

1. A semi-direct-drive permanent magnet wind turbine generator with a focusing magnet type, comprising a stator assembly (1) and a rotor assembly (2), wherein the rotor assembly (2) is coaxially disposed on the radially inner side of the stator assembly (1), and an air gap is formed between the stator assembly (1) and the rotor assembly (2), characterized in that, The rotor assembly (2) includes a plurality of rotor cores (22) distributed circumferentially. With reference to any of the rotor cores (22), a surface-mounted permanent magnet (23) is provided on the side of the rotor core (22) facing the air gap. The rotor core (22) is provided with spoke-type permanent magnets (24) on both sides of its circumference, and the spoke-type permanent magnets (24) extend radially along the rotor assembly (2). The two spoke-type permanent magnets (24) located on both sides of the same rotor core (22) have the same magnetic pole on the side facing the rotor core (22); The rotor core (22) is provided with a cross-axis magnetic barrier (25), which extends along the axial direction of the rotor assembly (2). In the cross-section of the rotor assembly (2), the cross-axis magnetic barrier (25) is located in the circumferential middle region of the rotor core (22) and between the two spoke permanent magnets (24) on both sides of the same rotor core (22).

2. The magnetic-type semi-direct-drive permanent-magnetic wind generator according to claim 1, characterized in that, The spoke-type permanent magnet (24) is disposed between two adjacent rotor cores (22); The radial outer end of the spoke-type permanent magnet (24) is disposed adjacent to the circumferential end of the surface-mount permanent magnet (23).

3. The magnetic-type semi-direct-drive permanent-magnetic wind generator according to claim 1, characterized in that, The spoke-type permanent magnet (24) is a long strip-shaped permanent magnet. The length direction of the spoke-type permanent magnet (24) is arranged radially along the rotor assembly (2), and the thickness direction of the spoke-type permanent magnet (24) is arranged tangentially along the rotor assembly (2).

4. The magnetic-type semi-direct-drive permanent-magnetic wind generator according to claim 1, characterized in that, Within the cross-section of the rotor assembly (2), the centerline of the cross-axis magnetic barrier (25) coincides with the circumferential centerline between the two spoke permanent magnets (24) on both sides of the same rotor core (22).

5. The magnetic-clustering semi-direct-drive permanent-magnet wind generator according to claim 1, characterized in that, The cross-axis magnetic barrier (25) includes a slot that runs through the rotor core (22) along the axial direction of the rotor assembly (2).

6. The magnetic aggregation type semi-direct drive permanent magnetic wind driven generator according to claim 5, characterized in that, Within the cross-section of the rotor assembly (2), the cross-axis magnetic barrier (25) includes a plurality of empty slot segments arranged radially spaced along the rotor assembly (2), each empty slot segment being an elongated slot extending radially along the rotor assembly (2), and the circumferential width of each empty slot segment being less than its radial length, with a rotor core (22) connecting bridge remaining between two adjacent empty slot segments.

7. The magnetic aggregation type semi-direct drive permanent magnetic wind driven generator according to claim 6, characterized in that, The empty slot section includes a first empty slot section (251) and a second empty slot section (252), wherein the second empty slot section (252) is provided on both sides of the first empty slot section (251), and the second empty slot section (252) is symmetrical about the first empty slot section (251).

8. The magnetizing semi-direct drive permanent magnet wind turbine generator according to claim 7, characterized in that, The first empty slot section (251) is tapered in the direction close to the stator assembly (1).

9. The magnetic-clustering semi-direct-drive permanent-magnetic wind generator according to claim 1, characterized in that, The rotor assembly (2) further includes a sector magnetic barrier (26) with a sector slot, the sector magnetic barrier (26) being opened on the side of the rotor core (22) near the air gap and located between the radial outer end of the spoke permanent magnet (24) and the circumferential end of the surface-mount permanent magnet (23).

10. The magnetic-clustering semi-direct-drive permanent-magnetic wind generator according to claim 1, characterized in that, The radial thickness of the surface-mount permanent magnet (23) is less than the tangential thickness of the spoke permanent magnet (24), and half of the circumferential length of the surface-mount permanent magnet (23) is less than the radial length of the spoke permanent magnet (24).

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