Axial module combined reluctance assisted permanent magnet synchronous motor rotor and manufacturing method thereof

Abstract

An axial module combined reluctance assisted permanent magnet synchronous motor rotor and a manufacturing method thereof belong to the field of motor technology. The axial module combined reluctance assisted permanent magnet synchronous motor rotor comprises a rotor shaft and a plurality of NdFeB permanent magnet synchronous rotor modules arranged axially along the rotor shaft, a ferrite permanent magnet assisted synchronous reluctance rotor module is arranged between two adjacent NdFeB permanent magnet synchronous rotor modules, the ferrite permanent magnet assisted synchronous reluctance rotor module comprises a plurality of annular rotor laminations 1 and a plurality of ferrite permanent magnets, and the NdFeB permanent magnet synchronous rotor module comprises a plurality of annular rotor laminations 2 and a plurality of NdFeB permanent magnets. The axial module combined reluctance assisted permanent magnet synchronous motor rotor and a manufacturing method thereof can reduce the cost of the motor rotor, improve the temperature resistance of the rotor center, reduce eddy current loss, improve the speed expansion capability, improve the power factor and efficiency of the motor, and reduce the maintenance cycle.

Description

Technical Field

[0001] The present invention relates to the technical field of motors, and in particular to an axial module combined reluctance assisted permanent magnet synchronous motor rotor and a manufacturing method thereof. Background Art

[0002] Conventional permanent magnet synchronous motor rotors use neodymium iron boron permanent magnet material. Rare earth resources are non-renewable and expensive. In addition, when permanent magnet synchronous motors run at high speeds, the controller needs to provide a large current to weaken the permanent magnet due to excessive back electromotive force, which greatly increases the driver capacity requirements for the motor. The high price and thermal stability of the motor limit the promotion of this type of motor.

[0003] Permanent magnet assisted synchronous reluctance motors mostly use low-performance ferrite permanent magnet materials in the permanent magnet materials of the rotor, which are cheap and belong to renewable resources. However, due to the limited permanent magnet flux provided by ferrite permanent magnet materials, the power factor of the permanent magnet assisted synchronous motor is low when it is running at low speed. However, the weak magnetic current provided by the controller is lower than that of the permanent magnet synchronous motor when it is running at high speed. In addition, due to the high resistivity of ferrite materials, the rotor will have smaller eddy current losses than the NdFeB permanent magnet motor under the action of equal harmonic magnetic fields. The Curie temperature of ferrite is about 450 degrees Celsius, while the Curie temperature of NdFeB permanent magnet materials is generally 310 degrees Celsius. Therefore, under high eddy current losses and high-temperature and high-speed operation, the permanent magnet assisted synchronous reluctance motor has a reliable quality that is unmatched by the NdFeB permanent magnet motor.

[0004] The existing NdFeB permanent magnet synchronous motor has technical problems such as high price of NdFeB materials, thermal demagnetization of NdFeB permanent magnets due to eddy current loss and heat generation of NdFeB magnets and poor heat dissipation of rotors, limited transverse power operation range of NdFeB permanent magnet synchronous motors, and inconvenient maintenance and replacement of magnets after magnet demagnetization. The existing ferrite permanent magnet assisted synchronous reluctance motor has problems such as insufficient torque density, low power factor and weak overload capacity.

[0005] When the permanent magnet of a traditional built-in permanent magnet synchronous motor is partially demagnetized, all the magnetic steel must be destructively removed, which is unfavorable for maintenance costs and time. Summary of the invention

[0006] In order to solve the technical problems existing in the prior art, the present invention provides an axial module combined reluctance assisted permanent magnet synchronous motor rotor and a manufacturing method thereof, which can reduce the cost of the motor rotor, improve the temperature resistance of the rotor center, reduce eddy current losses, improve the speed expansion capability, improve the power factor and efficiency of the motor, and reduce the maintenance cycle.

[0007] In order to achieve the above object, the technical solution of the present invention is:

[0008] An axial module combined reluctance assisted permanent magnet synchronous motor rotor comprises a rotor shaft and a plurality of NdFeB permanent magnet synchronous rotor modules arranged axially along the rotor shaft, wherein a ferrite permanent magnet assisted synchronous reluctance rotor module is arranged between two adjacent NdFeB permanent magnet synchronous rotor modules;

[0009] The ferrite permanent magnet assisted synchronous reluctance rotor module comprises a plurality of annular rotor laminations 1 and a plurality of ferrite permanent magnets, wherein the plurality of rotor laminations 1 are fixed after being stacked, and the plurality of ferrite permanent magnets are uniformly inserted in the stacked rotor laminations 1 along the circumferential direction;

[0010] The NdFeB permanent magnet synchronous rotor module includes a plurality of annular rotor laminations 2 and a plurality of NdFeB permanent magnets. The plurality of rotor laminations 2 are fixed after being laminated, and the plurality of NdFeB permanent magnets are uniformly inserted in the laminated rotor laminations 2 along the circumferential direction.

[0011] Furthermore, the rotor lamination 1 includes a circular ring-shaped magnetic silicon steel sheet 1 and a plurality of groups of magnetic steel slots evenly arranged along the circumference of the magnetic silicon steel sheet, and the group of magnetic steel slots includes 2-5 layers of magnetic steel slots 1, and the ferrite permanent magnet and air magnetic barrier 1 are arranged in the magnetic steel slots 1.

[0012] Furthermore, the rotor lamination 2 includes an annular magnetic silicon steel sheet 2 and a plurality of magnetic steel slots 2 evenly arranged along the circumference of the magnetic silicon steel sheet 2, and the NdFeB permanent magnets and air magnetic barriers 2 are arranged in the magnetic steel slots 2.

[0013] Furthermore, a magnetic isolation bridge 1 is provided between the magnetic steel slot 1 and the outer circle of the magnetic silicon steel sheet 1, and a magnetic isolation bridge 2 is provided between the magnetic steel slot 2 and the outer circle of the magnetic silicon steel sheet 2.

[0014] Furthermore, the NdFeB permanent magnet synchronous rotor module and the ferrite permanent magnet assisted synchronous reluctance rotor module are respectively interference fit with the rotor shaft.

[0015] Furthermore, a positioning protrusion is axially arranged on the outside of the rotor shaft, and a positioning groove cooperating with the positioning protrusion is provided on the inner side of the NdFeB permanent magnet synchronous rotor module and the ferrite permanent magnet assisted synchronous reluctance rotor module. Specifically, the rotor lamination 1 and the rotor lamination 2 are both provided with positioning grooves, which respectively constitute the positioning grooves of the NdFeB permanent magnet synchronous rotor module and the ferrite permanent magnet assisted synchronous reluctance rotor module after being stacked.

[0016] Furthermore, magnetic steel pressure plates are provided at the ends of the NdFeB permanent magnet synchronous rotor modules located at both ends of the rotor.

[0017] Furthermore, the ferrite permanent magnet assisted synchronous reluctance rotor module is a built-in structure, and the neodymium iron boron permanent magnet synchronous rotor module is a built-in structure or a surface-mounted structure.

[0018] A method for manufacturing an axial module combined reluctance assisted permanent magnet synchronous motor rotor, used for the above axial module combined reluctance assisted permanent magnet synchronous motor rotor, comprises the following steps:

[0019] S1, according to the angle between the d-axis 1 of the ferrite permanent magnet assisted synchronous reluctance rotor module and the d-axis 2 of the neodymium iron boron permanent magnet synchronous rotor module, respectively processing the positioning grooves on the inner sides of the rotor lamination 1 and the rotor lamination 2;

[0020] The angle between the d-axis 1 of the ferrite permanent magnet assisted synchronous reluctance rotor module and the d-axis 2 of the NdFeB permanent magnet synchronous rotor module is determined as follows:

[0021] (1) Determine the internal power factor angle of the ferrite permanent magnet assisted synchronous reluctance rotor module to generate maximum torque:

[0022] According to the torque expression of permanent magnet synchronous motor:

[0023]

[0024] Where, T em1 is the motor torque, p is the number of motor pole pairs, ψ pm1 is the flux generated by the permanent magnet of the ferrite permanent magnet assisted synchronous reluctance rotor module, i s is the stator current space vector, β 1 for i s The angle between the ferrite permanent magnet assisted synchronous reluctance rotor module and the d-axis, L dpm1 is the direct-axis inductance of the ferrite permanent magnet assisted synchronous reluctance rotor module, L qpm1 is the quadrature-axis inductance of the ferrite permanent magnet assisted synchronous reluctance rotor module;

[0025] Among them, p, ψ pm1 , L dpm1 , L qpm1 and i s All are known quantities. For the torque expression of the permanent magnet synchronous motor, β 1 Take the derivative of the function and find the maximum point as β PMA-SynRM , that is, the internal power factor angle of the ferrite permanent magnet assisted synchronous reluctance rotor module to generate maximum torque is β PMA-SynRM Spend;

[0026] (2) Determine the internal power factor angle of the NdFeB permanent magnet synchronous rotor module to generate maximum torque:

[0027] According to the torque expression of permanent magnet synchronous motor:

[0028]

[0029] Where, T em2 is the motor torque, p is the number of motor pole pairs, ψ pm2 is the flux generated by the permanent magnet of the NdFeB permanent magnet synchronous rotor module, i s is the stator current space vector, β 2 for i s The angle between the d-axis and the NdFeB permanent magnet synchronous rotor module, L dpm2 is the direct-axis inductance of the NdFeB permanent magnet synchronous rotor module, L qpm2 is the quadrature axis inductance of the NdFeB permanent magnet synchronous rotor module;

[0030] Among them, p, ψ pm2 , L dpm2 , L qpm2 and i s All are known quantities. For the torque expression of the permanent magnet synchronous motor, β 2 Take the derivative of the function and find the maximum point as β pm , that is, the internal power factor angle of the NdFeB permanent magnet synchronous rotor module to generate the maximum torque is β pm Spend;

[0031] (3) The d-axis 2 of the NdFeB permanent magnet synchronous rotor module is projected along the rotor axis onto the ferrite permanent magnet assisted synchronous reluctance rotor module. The angle between the d-axis 2 and the d-axis 1 of the ferrite permanent magnet assisted synchronous reluctance rotor module after projection is (β PMA-SynRM -β pm ) / p degrees, that is, the angle between the d-axis 1 of the ferrite permanent magnet assisted synchronous reluctance rotor module and the d-axis 2 of the NdFeB permanent magnet synchronous rotor module is (β PMA-SynRM -β pm ) / p degrees;

[0032] S2, a plurality of rotor laminations are stacked and fixed, and then ferrite permanent magnets are inserted to form a ferrite permanent magnet assisted synchronous reluctance rotor module; a plurality of rotor laminations are stacked and fixed, and then NdFeB permanent magnets are inserted to form a NdFeB permanent magnet synchronous rotor module;

[0033] S3, sequentially mounting the NdFeB permanent magnet synchronous rotor module and the ferrite permanent magnet assisted synchronous reluctance rotor module on the rotor shaft.

[0034] Beneficial effects of the present invention:

[0035] 1) The present invention replaces part of the middle position of the NdFeB permanent magnet synchronous rotor module in the rotor of the NdFeB permanent magnet synchronous motor with a low-cost ferrite permanent magnet auxiliary synchronous reluctance rotor module of equal power to solve the technical problem of the high price of the existing NdFeB permanent magnet synchronous motor, and also solves the problem of permanent magnet thermal demagnetization in the middle of the rotor of the existing NdFeB permanent magnet synchronous motor due to eddy current loss of permanent magnets and limited heat dissipation capacity of the rotor; the rotor center module is replaced with a permanent magnet auxiliary rotor module, thereby reducing the no-load back electromotive force of the motor. To solve the technical problem of the limited lateral power operation range of the existing NdFeB permanent magnet synchronous motor; combine the motor rotor axial modules, and when the motor rotor fails, directly replace the faulty module separately to solve the technical problem of the inconvenience of replacing the magnet after the magnet is demagnetized in the existing NdFeB permanent magnet synchronous motor; add high-performance NdFeB permanent magnet materials to the ferrite permanent magnet assisted synchronous reluctance motor to solve the technical problems of insufficient torque density, weak overload capacity and insufficient power factor when running at low speed in the ferrite permanent magnet assisted synchronous reluctance motor;

[0036] 2) Compared with traditional permanent magnet synchronous motors, the rotor intermediate module uses relatively low-priced ferrite permanent magnet materials, which can reduce the motor rotor cost by about 15%, increase the motor rotor center temperature resistance by 50 degrees, reduce eddy current loss by 22%, and increase the speed expansion capability by 25%;

[0037] 3) Compared with the traditional ferrite permanent magnet assisted synchronous reluctance motor, the use of high-performance NdFeB permanent magnet materials at both ends of the rotor increases the power factor and efficiency of the motor by 10% respectively, and the synchronous reluctance motor with the same overload capacity can save 30% of the volume;

[0038] 4) For motors with rotor failures, reduce maintenance cycles and increase recycling rates of rare earth materials;

[0039] 5) The motor of the present invention can be widely used in various fields such as new energy vehicles, fans and pumps, air compressors, etc. It has higher efficiency and power factor than permanent magnet assisted synchronous reluctance motors, and has an absolute price advantage over NdFeB permanent magnet synchronous reluctance motors, and has obvious energy-saving and environmental protection effects.

[0040] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 is a structural schematic diagram of a ferrite permanent magnet assisted synchronous reluctance rotor module provided in an embodiment of the present invention;

[0042] Figure 2 is a schematic structural diagram of a NdFeB permanent magnet synchronous rotor module provided in an embodiment of the present invention;

[0043] Figure 3 It is an exploded view of an axial module combined reluctance assisted permanent magnet synchronous motor rotor provided by an embodiment of the present invention;

[0044] Figure 4 It is a schematic diagram of the overall structure of an axial module combined reluctance assisted permanent magnet synchronous motor rotor provided by an embodiment of the present invention;

[0045] Figure 5 is the operating space vector of the permanent magnet synchronous motor provided by the embodiment of the present invention Figure 1 ;

[0046] Figure 6 is the operating space vector of the permanent magnet synchronous motor provided by the embodiment of the present invention Figure 2 .

[0047] The reference numerals in the drawings of the specification include:

[0048] 1-Ferrite permanent magnet, 2-Magnetic isolation bridge 1, 3-Air magnetic barrier 1, 4-Magnetic conductive silicon steel sheet 1, 5-Rotor shaft, 6-Air magnetic barrier 2, 7-NdFeB permanent magnet, 8-Magnetic isolation bridge 2, 9-Magnetic conductive silicon steel sheet 2, 10-NdFeB permanent magnet synchronous rotor module, 11-Ferrite permanent magnet assisted synchronous reluctance rotor module, 12-Magnetic steel pressure plate. DETAILED DESCRIPTION

[0049] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0050] In the description of the present invention, unless otherwise specified and limited, it should be noted that the terms "installation", "connection" and "connection" should be understood in a broad sense. For example, it can be a mechanical connection or an electrical connection, or it can be the internal connection of two components, it can be a direct connection, or it can be indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to the specific circumstances. In addition, in the description of the present invention, some components or structures in the ferrite permanent magnet assisted synchronous reluctance rotor module 11 and the neodymium iron boron permanent magnet synchronous rotor module 10 are distinguished by "one" and "two". For example, the "magnetic isolation bridge, air magnetic barrier, magnetic silicon steel sheet, air magnetic barrier, q-axis and d-axis" of the ferrite permanent magnet assisted synchronous reluctance rotor module 11 are all distinguished by "one"; the "magnetic isolation bridge, air magnetic barrier, magnetic silicon steel sheet, air magnetic barrier, q-axis and d-axis" of the neodymium iron boron permanent magnet synchronous rotor module 10 are all distinguished by "two".

[0051] In order to solve the problems existing in the prior art, such as Figures 1 to 6As shown, the present invention provides an axial module combined reluctance assisted permanent magnet synchronous motor rotor, comprising a rotor shaft 5 and a plurality of NdFeB permanent magnet synchronous rotor modules 10 arranged axially along the rotor shaft 5, and a ferrite permanent magnet assisted synchronous reluctance rotor module 11 is arranged between two adjacent NdFeB permanent magnet synchronous rotor modules 10;

[0052] The ferrite permanent magnet assisted synchronous reluctance rotor module 11 comprises a plurality of annular rotor laminations 1 and a plurality of ferrite permanent magnet steels 1, wherein the plurality of rotor laminations 1 are laminated and fixed, and the plurality of ferrite permanent magnet steels 1 are uniformly inserted in the laminated plurality of rotor laminations 1 along the circumferential direction;

[0053] The NdFeB permanent magnet synchronous rotor module 10 comprises a plurality of annular rotor laminations 2 and a plurality of NdFeB permanent magnets 7. The plurality of rotor laminations 2 are laminated and fixed, and the plurality of NdFeB permanent magnets 7 are uniformly inserted in the laminated rotor laminations 2 along the circumferential direction.

[0054] like Figure 1 and Figure 2 As shown, rotor lamination 1 includes an annular magnetic silicon steel sheet 14 and a plurality of magnetic steel slots evenly arranged along the circumference of magnetic silicon steel sheet 14, a magnetic steel slot group includes 2-5 layers of magnetic steel slots 1, and ferrite permanent magnets 1 and air magnetic barriers 13 are arranged in magnetic steel slots 1. Rotor lamination 2 includes an annular magnetic silicon steel sheet 29 and a plurality of magnetic steel slots evenly arranged along the circumference of magnetic silicon steel sheet 29, and neodymium iron boron permanent magnets 7 and air magnetic barriers 26 are arranged in magnetic steel slots 2. A magnetic isolation bridge 12 is arranged between magnetic steel slot 1 and the outer circle of magnetic silicon steel sheet 14, and a magnetic isolation bridge 28 is arranged between magnetic steel slot 2 and the outer circle of magnetic silicon steel sheet 29.

[0055] In the present invention, after a plurality of rotor laminations of the ferrite permanent magnet assisted synchronous reluctance rotor module 11 are stacked, they are independently fixed by bolts and screws; after a plurality of rotor laminations of the NdFeB permanent magnet synchronous rotor module 10 are stacked, they are independently fixed by bolts and screws. After the NdFeB permanent magnet synchronous rotor module 10 and the ferrite permanent magnet assisted synchronous reluctance rotor module 11 are manufactured, they are fixed to the rotor shaft 5. Each module is interference fit with the rotor shaft 5, and the positioning is achieved by the cooperation between the positioning protrusion of the rotor shaft 5 and the positioning groove of each module. For the problem of the deflection angle of different modules, the positioning grooves are opened at different positions of the modules to solve it. In this embodiment, a group of magnetic steel slots includes 4 layers of magnetic steel slots. A ferrite permanent magnet 1 is arranged in the middle of the magnetic steel slot after the rotor laminations are stacked. Air magnetic barriers 3 are formed on both sides of the ferrite permanent magnet 1 in the magnetic steel slot. The ferrite permanent magnet 1 provides permanent magnet torque, and the magnetic conductive silicon steel sheet 4 provides reluctance torque. The ferrite permanent magnet assisted synchronous reluctance rotor module 11 adopts a multi-layer permanent magnet structure, and a magnetic isolation bridge 2 is arranged between each layer of permanent magnets and the outer circle of the rotor. In order to consider the mechanical stress problem between each layer of permanent magnets, the magnetic steel slots with weak stress links are provided with reinforcing rib structures. The structures of magnetic steel slots 1 and 2 are processed by optimizing algorithms by comprehensively considering electromagnetic, mechanical, temperature, and torque pulsations, resulting in different arrangements and shapes. A neodymium iron boron permanent magnet 7 is arranged in the middle of the magnetic steel slot 2 after the rotor laminations are stacked, and air magnetic barriers 2 6 are formed on both sides of the neodymium iron boron permanent magnet 7 in the magnetic steel slot 2.

[0056] like Figure 3 and Figure 4 As shown, the NdFeB permanent magnet synchronous rotor module 10 and the ferrite permanent magnet assisted synchronous reluctance rotor module 11 are respectively interference fit with the rotor shaft 5. A positioning protrusion is axially arranged on the outside of the rotor shaft 5, and a positioning groove that cooperates with the positioning protrusion is opened on the inner side of the NdFeB permanent magnet synchronous rotor module 10 and the ferrite permanent magnet assisted synchronous reluctance rotor module 11. The axial module combination is carried out by cooperating with the positioning protrusion and the positioning groove, so as to realize the positioning of the rotor shaft 5 with the NdFeB permanent magnet synchronous rotor module 10 and the ferrite permanent magnet assisted synchronous reluctance rotor module 11 respectively. In this embodiment, two NdFeB permanent magnet synchronous rotor modules 10 are provided, and a ferrite permanent magnet assisted synchronous reluctance rotor module 11 is provided between the two NdFeB permanent magnet synchronous rotor modules 10. The three modules are sequentially mounted on the rotor shaft 5 by cooperating with the positioning protrusion and the positioning groove. A magnetic steel pressure plate 12 is provided at the end of the NdFeB permanent magnet synchronous rotor module 10 located at both ends of the rotor. Since the structure of the middle ferrite permanent magnet assisted synchronous reluctance rotor module 11 is different from that of the NdFeB permanent magnet synchronous rotor modules 10 at both ends, the middle ferrite permanent magnet assisted synchronous reluctance rotor module 11 does not require a pressure plate. It is only necessary to add a magnetic steel pressure plate 12 to the end of the NdFeB permanent magnet synchronous rotor module 10 located at the end of the rotor.

[0057] Preferably, the ferrite permanent magnet assisted synchronous reluctance rotor module 11 is a built-in structure, and the NdFeB permanent magnet synchronous rotor module 10 is a built-in structure or a surface mount structure. Specifically, when the NdFeB permanent magnet synchronous rotor module 10 is a built-in structure, a built-in "I" shape, a built-in "V" shape, or a built-in "W" shape structure can be adopted. For low-speed operation, the NdFeB permanent magnet synchronous rotor module 10 can also adopt a rotor tangential structure.

[0058] A method for manufacturing an axial module combined reluctance assisted permanent magnet synchronous motor rotor, used for the above axial module combined reluctance assisted permanent magnet synchronous motor rotor, comprises the following steps:

[0059] S1, according to the angle between the d-axis 1 of the ferrite permanent magnet assisted synchronous reluctance rotor module 11 and the d-axis 2 of the NdFeB permanent magnet synchronous rotor module 10, respectively processing the positioning grooves on the inner sides of the rotor lamination 1 and the rotor lamination 2;

[0060] like Figure 5 and Figure 6 As shown, the angle between the d-axis 1 of the ferrite permanent magnet assisted synchronous reluctance rotor module 11 and the d-axis 2 of the NdFeB permanent magnet synchronous rotor module 10 is determined as follows:

[0061] (1) Determine the internal power factor angle of the ferrite permanent magnet assisted synchronous reluctance rotor module 11 that generates the maximum torque:

[0062] According to the torque expression of permanent magnet synchronous motor:

[0063]

[0064] Where, T em1 is the motor torque, p is the number of motor pole pairs, ψ pm1 is the flux generated by the permanent magnet of the ferrite permanent magnet assisted synchronous reluctance rotor module 11, i s is the stator current space vector, β 1 for i s The angle L between the ferrite permanent magnet assisted synchronous reluctance rotor module 11 and the d-axis is dpm1 is the direct-axis inductance of the ferrite permanent magnet assisted synchronous reluctance rotor module 11, L qpm1 is the quadrature-axis inductance of the ferrite permanent magnet assisted synchronous reluctance rotor module 11;

[0065] Among them, after the rotor design is completed, p, ψ pm1 , L dpm1 , L qpm1 and i s All are known quantities. For the torque expression of the permanent magnet synchronous motor, β 1 Take the derivative of the function and find the maximum point as β PMA-SynRM, that is, the internal power factor angle of the ferrite permanent magnet assisted synchronous reluctance rotor module 11 to generate the maximum torque is β PMA-SynRM Spend;

[0066] Figure 5 in,i d for i s The decomposition into the direct axis component of the ferrite permanent magnet assisted synchronous reluctance rotor module 11, i q for i s The decomposition into the quadrature axis component of the ferrite permanent magnet assisted synchronous reluctance rotor module 11, ψ 0 for i s The magnetic flux generated, ψ s is 0 With ψ pm The synthetic magnetic flux of 0 An angle with the d-axis of the ferrite permanent magnet assisted synchronous reluctance rotor module 11;

[0067] (2) Determine the internal power factor angle of the NdFeB permanent magnet synchronous rotor module 10 that generates the maximum torque:

[0068] According to the torque expression of permanent magnet synchronous motor:

[0069]

[0070] Where, T em2 is the motor torque, p is the number of motor pole pairs, ψ pm2 is the flux generated by the permanent magnet of the NdFeB permanent magnet synchronous rotor module 10, i s is the stator current space vector, β 2 for i s The angle L between the d-axis and the NdFeB permanent magnet synchronous rotor module 10 is dpm2 is the direct axis inductance of the NdFeB permanent magnet synchronous rotor module 10, L qpm2 is the quadrature-axis inductance of the NdFeB permanent magnet synchronous rotor module 10;

[0071] Among them, after the rotor design is completed, p, ψ pm2 , L dpm2 , L qpm2 and i s All are known quantities. For the torque expression of the permanent magnet synchronous motor, β 2 Take the derivative of the function and find the maximum point as β pm , that is, the internal power factor angle of the NdFeB permanent magnet synchronous rotor module 10 to generate the maximum torque is β pm Spend;

[0072] (3) The d-axis 2 of the NdFeB permanent magnet synchronous rotor module 10 is projected along the rotor shaft 5 onto the ferrite permanent magnet assisted synchronous reluctance rotor module 11. The angle between the d-axis 2 and the d-axis 1 of the ferrite permanent magnet assisted synchronous reluctance rotor module 11 after projection is (β PMA-SynRM -β pm ) / p degrees, that is, the angle between the d-axis 1 of the ferrite permanent magnet assisted synchronous reluctance rotor module 11 and the d-axis 2 of the NdFeB permanent magnet synchronous rotor module 10 is (β PMA-SynRM -β pm ) / p degrees;

[0073] Figure 6 in,i d for i s The decomposition into the direct axis component of the NdFeB permanent magnet synchronous rotor module 10, i q for i s The decomposition into the quadrature axis component of the NdFeB permanent magnet synchronous rotor module 10, ψ 0 for i s The magnetic flux generated, ψ s is 0 With ψ pm The synthetic magnetic flux of 0 An angle with the d-axis 2 of the NdFeB permanent magnet synchronous rotor module 10;

[0074] S2, a plurality of rotor laminations are stacked and fixed, and then a ferrite permanent magnet steel 1 is inserted to form a ferrite permanent magnet assisted synchronous reluctance rotor module 11; a plurality of rotor laminations are stacked and fixed, and then a neodymium iron boron permanent magnet steel 7 is inserted to form a neodymium iron boron permanent magnet synchronous rotor module 10;

[0075] S3, sequentially mounting the NdFeB permanent magnet synchronous rotor module 10 and the ferrite permanent magnet assisted synchronous reluctance rotor module 11 on the rotor shaft 5.

[0076] The operating mechanism of the axial module combined reluctance assisted permanent magnet synchronous motor rotor of the present invention is as follows:

[0077] Since the ferrite permanent magnet assisted synchronous reluctance rotor module 11 provides a small amount of permanent magnet torque and a large amount of reluctance torque, and the magnetic steel of the ferrite permanent magnet assisted synchronous reluctance rotor module 11 is made of ferrite material, the no-load back electromotive force generated by the ferrite permanent magnet assisted synchronous reluctance rotor module 11 is not high, which can provide a good space for the lateral power operation of the motor. Figure 1 In the figure, the magnetic flux path of the motor's q-axis is between each layer of permanent magnets. Due to the presence of permanent magnets, the motor's d-axis magnetic resistance is larger and the inductance is smaller, while the q-axis is made of magnetic conductive materials, so the magnetic resistance is smaller and the inductance is larger.

[0078] The NdFeB permanent magnet synchronous rotor module 10 is the main back-EMF and torque output module of the rotor of the present invention. Due to the high magnetic energy product of the NdFeB rare earth material, it can generate a very high torque density, thereby improving the overall performance of the motor rotor;

[0079] Since the operating principles of the ferrite permanent magnet assisted synchronous reluctance rotor module 11 and the NdFeB permanent magnet synchronous rotor module 10 are different, in the initial stage of rotor design, the coupling problem of the ferrite permanent magnet assisted synchronous reluctance rotor module 11 and the NdFeB permanent magnet synchronous rotor module 10 is not considered first, and the performance of each module is considered separately. Under the maximum torque current ratio control (MTPA) mode, the internal power factor angle of the NdFeB permanent magnet synchronous rotor module 10 to generate the maximum torque is β pm The internal power factor angle of the ferrite permanent magnet assisted synchronous reluctance rotor module 11 to generate the maximum torque is β PMA-SynRM degree, the ferrite permanent magnet assisted synchronous reluctance rotor module 11 needs to be rotated tangentially in the opposite direction of the motor rotation (β PMA-SynRM -β pm ) / p degrees, where p is the number of motor pole pairs. The torque pulsation of the rotor is then optimized based on 3D modeling and simulation before fine-tuning.

[0080] In the present invention, since the rotor adopts a modular combination structure, for the module with rotor failure, only the faulty module needs to be replaced after detection, which can greatly speed up the rotor maintenance speed and maintenance cost. In addition, since the rotor module combination structure exists independently for the mechanical structure, each module can be repaired and replaced in units of blocks. For example, high-temperature thermal demagnetization of traditional permanent magnet synchronous motors is mainly located at the center axis of the rotor. The module can be replaced at the center axis, providing convenient conditions for the maintenance of traditional permanent magnet motor rotors, improving maintenance efficiency and reducing maintenance costs.

[0081] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. An axial module combined reluctance assisted permanent magnet synchronous motor rotor, It is characterized in that It includes a rotor shaft and a plurality of NdFeB permanent magnet synchronous rotor modules arranged along the axial direction of the rotor shaft, and a ferrite permanent magnet assisted synchronous reluctance rotor module is arranged between two adjacent NdFeB permanent magnet synchronous rotor modules; The ferrite permanent magnet assisted synchronous reluctance rotor module comprises a plurality of annular rotor laminations 1 and a plurality of ferrite permanent magnets. After the plurality of rotor laminations 1 are stacked, they are independently fixed by bolts and screws. The plurality of ferrite permanent magnets are uniformly inserted in the stacked rotor laminations 1 along the circumferential direction. The NdFeB permanent magnet synchronous rotor module comprises a plurality of annular rotor laminations 2 and a plurality of NdFeB permanent magnets. After the plurality of rotor laminations 2 are laminated, they are independently fixed by bolts and screws. The plurality of NdFeB permanent magnets are uniformly inserted in the laminated rotor laminations 2 along the circumferential direction. The rotor lamination 1 includes a circular magnetic silicon steel sheet 1 and a plurality of groups of magnetic steel slots uniformly arranged along the circumference of the magnetic silicon steel sheet, wherein the group of magnetic steel slots includes 2-5 layers of magnetic steel slots 1, and the ferrite permanent magnet and air magnetic barrier 1 are arranged in the magnetic steel slots 1; The rotor lamination 2 comprises an annular magnetic silicon steel sheet 2 and a plurality of magnetic steel slots 2 evenly arranged along the circumference of the magnetic silicon steel sheet 2, wherein the NdFeB permanent magnet and the air magnetic barrier 2 are arranged in the magnetic steel slots 2; The NdFeB permanent magnet synchronous rotor module and the ferrite permanent magnet assisted synchronous reluctance rotor module are respectively interference fit with the rotor shaft.

2. The axial module combined reluctance assisted permanent magnet synchronous motor rotor according to claim 1, It is characterized in that A magnetic isolation bridge 1 is arranged between the magnetic steel slot 1 and the outer circle of the magnetic conductive silicon steel sheet 1, and a magnetic isolation bridge 2 is arranged between the magnetic steel slot 2 and the outer circle of the magnetic conductive silicon steel sheet 2.

3. The axial module combined reluctance assisted permanent magnet synchronous motor rotor according to any one of claims 1 to 2, It is characterized in that The outer part of the rotor shaft is provided with a positioning protrusion along the axial direction, and the inner sides of the NdFeB permanent magnet synchronous rotor module and the ferrite permanent magnet assisted synchronous reluctance rotor module are both provided with a positioning groove matched with the positioning protrusion.

4. The axial module combined reluctance assisted permanent magnet synchronous motor rotor according to any one of claims 1 to 2, It is characterized in that Magnetic steel pressure plates are arranged at the ends of the NdFeB permanent magnet synchronous rotor modules located at both ends of the rotor.

5. The axial module combined reluctance assisted permanent magnet synchronous motor rotor according to any one of claims 1 to 2, It is characterized in that The ferrite permanent magnet assisted synchronous reluctance rotor module is a built-in structure, and the neodymium iron boron permanent magnet synchronous rotor module is a built-in structure or a surface-mounted structure.

6. A method for manufacturing an axial module combined reluctance assisted permanent magnet synchronous motor rotor, used for the axial module combined reluctance assisted permanent magnet synchronous motor rotor according to claim 1, It is characterized in that The steps include: S1, according to the angle between the d-axis 1 of the ferrite permanent magnet assisted synchronous reluctance rotor module and the d-axis 2 of the neodymium iron boron permanent magnet synchronous rotor module, respectively processing the positioning grooves on the inner sides of the rotor lamination 1 and the rotor lamination 2; The angle between the d-axis 1 of the ferrite permanent magnet assisted synchronous reluctance rotor module and the d-axis 2 of the NdFeB permanent magnet synchronous rotor module is determined as follows: (1) Determine the internal power factor angle of the ferrite permanent magnet assisted synchronous reluctance rotor module to generate maximum torque: According to the torque expression of permanent magnet synchronous motor: Where, T em1 is the motor torque, p is the number of motor pole pairs, ψ pm1 is the flux generated by the permanent magnet of the ferrite permanent magnet assisted synchronous reluctance rotor module, i s is the stator current space vector, β 1 for i s The angle between the ferrite permanent magnet assisted synchronous reluctance rotor module and the d-axis, L dpm1 is the direct-axis inductance of the ferrite permanent magnet assisted synchronous reluctance rotor module, L qpm1 is the quadrature-axis inductance of the ferrite permanent magnet assisted synchronous reluctance rotor module; Among them, p, ψ pm1 , L dpm1 , L qpm1 and i s All are known quantities. For the torque expression of the permanent magnet synchronous motor, β 1 Take the derivative of the function and find the maximum point as β PMA-SynRM , that is, the internal power factor angle of the ferrite permanent magnet assisted synchronous reluctance rotor module to generate maximum torque is β PMA-SynRM Spend; (2) Determine the internal power factor angle of the NdFeB permanent magnet synchronous rotor module to generate maximum torque: According to the torque expression of permanent magnet synchronous motor: Where, T em2 is the motor torque, p is the number of pole pairs of the motor, ψ pm2 is the magnetic flux generated by the permanent magnet of the NdFeB permanent magnet synchronous rotor module, i s is the stator current space vector, β 2 is the angle between i s and the d-axis two of the NdFeB permanent magnet synchronous rotor module, L dpm2 is the direct-axis inductance of the NdFeB permanent magnet synchronous rotor module, L qpm2 is the quadrature-axis inductance of the NdFeB permanent magnet synchronous rotor module; Among them, p, ψ pm2 , L dpm2 , L qpm2 and i s All are known quantities. For the torque expression of the permanent magnet synchronous motor, β 2 Take the derivative of the function and find the maximum point as β pm , that is, the internal power factor angle of the NdFeB permanent magnet synchronous rotor module to generate maximum torque is β pm Spend; (3) The d-axis 2 of the NdFeB permanent magnet synchronous rotor module is projected along the rotor axis onto the ferrite permanent magnet assisted synchronous reluctance rotor module. The angle between the d-axis 2 and the d-axis 1 of the ferrite permanent magnet assisted synchronous reluctance rotor module after projection is (β PMA-SynRM- β pm ) / p degrees, that is, the angle between the d-axis 1 of the ferrite permanent magnet assisted synchronous reluctance rotor module and the d-axis 2 of the NdFeB permanent magnet synchronous rotor module is (β PMA-SynRM- β pm ) / p Spend; S2, a plurality of rotor laminations are stacked and fixed, and then ferrite permanent magnets are inserted to form a ferrite permanent magnet assisted synchronous reluctance rotor module; a plurality of rotor laminations are stacked and fixed, and then NdFeB permanent magnets are inserted to form a NdFeB permanent magnet synchronous rotor module; S3, sequentially mounting the NdFeB permanent magnet synchronous rotor module and the ferrite permanent magnet assisted synchronous reluctance rotor module on the rotor shaft.

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