High-speed permanent magnet motor rotor with sinusoidal magnetomotive force distribution law and manufacturing method

Abstract

A high-speed permanent magnet motor rotor with a sinusoidal magnetomotive force distribution law and a manufacturing method thereof, comprising a rotating shaft, a sintered permanent magnet unit, a magnetic powder film and carbon fiber composite unit and a rotor sleeve composed of multiple layers of carbon fiber III arranged in sequence from the inside to the outside in the radial direction; the magnetic powder film and carbon fiber composite unit is composed of several magnetic powder film and carbon fiber composite subunits, each of which is composed of a magnetic powder film layer block, a film layer block and a carbon fiber layer; the number of magnetic powder film layer blocks and film layer blocks is the same as the number of sintered permanent magnet blocks, and the sum of the pole arc coefficient of the magnetic powder film layer block and the pole arc coefficient of the film layer block is always 1. The high-speed permanent magnet motor rotor of the present invention can improve the mechanical strength of the motor rotor, reduce the eddy current loss of the motor rotor, and increase the allowable linear speed of the motor rotor, thereby solving the problem of large temperature rise and low allowable linear speed of the eddy current loss of the traditional high-speed permanent magnet motor rotor.

Description

Technical Field

[0001] The present invention belongs to the technical field of motors, and in particular relates to a high-speed permanent magnet motor rotor with a sinusoidal magnetomotive force distribution law and a manufacturing method thereof. The rotor can be applied to high-speed permanent magnet motors. Background Art

[0002] With the rapid development of modern industry and the leap forward in aerospace technology, high-speed motors and generators with small size, light weight and high power density have received great attention from the international electrical engineering community and have been widely used in many modern industrial application fields, such as turbomolecular pumps, centrifuges, high-speed machine tools, compressors, flywheel energy storage, aerospace, etc.

[0003] Permanent magnet motors are particularly suitable for high-speed and high-performance motor systems due to their outstanding advantages such as high efficiency and power factor and wide speed operating range. They have now become the mainstream of high-speed motor research and application. However, the existing high-speed permanent magnet motor rotor has large eddy current losses and the motor rotor has difficulty in heat dissipation, resulting in excessive temperature rise of the motor rotor, which increases the risk of irreversible demagnetization of the rotor permanent magnet at high temperatures, and thus seriously endangers the safe operation of the motor. In addition, the strength problem of the high-speed permanent magnet motor rotor is also more prominent, because the permanent magnet cannot withstand the tensile stress generated by high-speed rotation, so appropriate protection measures must be taken for the permanent magnet. Summary of the invention

[0004] The present invention proposes a high-speed permanent magnet motor rotor with a sinusoidal magnetomotive force distribution law and a manufacturing method. Its purpose is to improve the mechanical strength of the motor rotor, reduce eddy current losses in the motor rotor, and increase the allowable linear speed of the motor rotor under the premise of ensuring the strength of the excitation magnetic field of the traditional high-speed permanent magnet motor rotor, thereby solving the bottleneck technology that restricts the development of high-speed permanent magnet motors to higher power and higher speed, that is, the bottleneck technology that the power and speed improvement are limited by the temperature rise and strength of the rotor.

[0005] In order to achieve the above object, the present invention adopts the following technical solution:

[0006] A high-speed permanent magnet motor rotor with a sinusoidal magnetomotive force distribution law comprises a rotating shaft, a sintered permanent magnet unit, a magnetic powder film and carbon fiber composite unit and a rotor sleeve; the rotating shaft is located at the innermost side of the high-speed permanent magnet motor rotor, the outer side of the rotating shaft is coaxially sleeved with a sintered permanent magnet unit, the outer side of the sintered permanent magnet unit is coaxially sleeved with a magnetic powder film and carbon fiber composite unit, the outer side of the magnetic powder film and carbon fiber composite unit is provided with a rotor sleeve, and the rotor sleeve is located at the outermost side of the high-speed permanent magnet motor rotor and is composed of a plurality of carbon fiber layers III;

[0007] The magnetic powder film and carbon fiber composite unit is composed of a plurality of magnetic powder film and carbon fiber composite sub-units, and each magnetic powder film and carbon fiber composite sub-unit has the same structure, and is composed of a magnetic powder film layer block, a film layer block and a carbon fiber layer II; the inner layer of the magnetic powder film and carbon fiber composite sub-unit is composed of a magnetic powder film layer block and a film layer block, and the outer layer is composed of a carbon fiber layer II, and the outer layer is arranged on the outside of the inner layer; the magnetic powder film layer block is formed by uniformly mixing magnetic powder and epoxy resin in a certain proportion and then curing.

[0008] The number of the magnetic powder film layer blocks and the film layer blocks is the same, and both are equal to the number of the sintered permanent magnet blocks; the pole arc coefficient of the magnetic powder film layer block decreases with the increase of the radius of the magnetic powder film and carbon fiber composite subunit, and the pole arc coefficient of the film layer block increases with the increase of the radius of the magnetic powder film and carbon fiber composite subunit, and the sum of the pole arc coefficient of the magnetic powder film layer block and the pole arc coefficient of the film layer block is always 1; the content of neodymium iron boron magnetic powder in the magnetic powder film layer block is ≥60%; the film layer block is formed by curing epoxy resin; the thickness of the magnetic powder film layer block is the same as that of the film layer block, and the single layer thickness is 0.2mm-0.25mm, and the single layer thickness of the magnetic powder film and carbon fiber composite subunit is ≤0.4mm.

[0009] The sintered permanent magnet unit comprises a sintered permanent magnet block, a sintered permanent magnet block gap and a carbon fiber layer I. The sintered permanent magnet blocks are symmetrically arranged in pairs, the thickness of the sintered permanent magnet blocks in the axial and circumferential directions is uniform, and the pole arc coefficient is less than 1; the gap formed between adjacent sintered permanent magnets is the sintered permanent magnet gap, and ferrite is filled in the sintered permanent magnet block gap; the carbon fiber layer I is wound around the outside of the sintered permanent magnet block and the ferrite, and the number of carbon fiber layer I is ≤4 layers, and the winding thickness is ≤0.8mm.

[0010] The number of carbon fiber layers III constituting the rotor sleeve is ≤10.

[0011] The sintered permanent magnet block is made of neodymium iron boron (NdFeB) permanent magnet with high remanence density; the carbon fiber layer is made of carbon fiber with good tensile performance; the rotating shaft is a magnetic shaft, which is made of material with good magnetic conductivity.

[0012] A method for manufacturing a high-speed permanent magnet motor rotor having a sinusoidal magnetomotive force distribution law comprises the following steps:

[0013] Step 1, uniformly mix magnetic powder and epoxy resin in a certain ratio and solidify them to form a magnetic powder film layer block; solidify the epoxy resin to form a film layer block, connect the magnetic powder film layer block and the film layer block end to end, and wind the carbon fiber layer II on the outside thereof to form a magnetic powder film and carbon fiber composite subunit;

[0014] Step 2, sticking the sintered permanent magnet blocks symmetrically arranged in pairs onto the outer circumferential surface of the rotating shaft; filling ferrite in the gap between the sintered permanent magnet blocks formed by adjacent sintered permanent magnet blocks, the ferrite and the sintered permanent magnet blocks together form an annular body, and winding the carbon fiber layer I on the outside of the annular body by applying tensile stress; the magnetic powder film and the carbon fiber composite sub-unit prepared in step 1 are successively wound on the outside of the carbon fiber layer I through interference fit, and during the winding process, it is necessary to ensure that the geometric center line of the magnetic powder film layer block in the magnetic powder film and the carbon fiber composite sub-unit coincides with the geometric center line of the sintered permanent magnet block, and the carbon fiber layer III is wound on the outside of the magnetic powder film and the carbon fiber composite unit by applying tensile stress, and the installation is completed.

[0015] The beneficial effects of the present invention are:

[0016] The high-speed permanent magnet motor rotor of the present invention includes a rotating shaft, a sintered permanent magnet unit, a magnetic powder film and carbon fiber composite unit and a rotor sleeve, which can not only generate an excitation magnetic field intensity comparable to that of a conventional high-speed permanent magnet motor rotor, but also has a high sinusoidal degree of the generated air gap magnetic field, thereby reducing the content of high-order harmonics in the motor. In addition, compared with conventional high-speed permanent magnet motor rotors, the high-speed permanent magnet motor rotor can improve the mechanical strength of the motor rotor, reduce the eddy current loss of the motor rotor, and increase the allowable linear speed of the motor rotor, thereby solving the problems of large temperature rise of eddy current loss and low allowable linear speed of conventional high-speed permanent magnet motor rotors, and exploring a new path for the development of high-speed permanent magnet motors towards higher power and higher speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The schematic diagram of the rotor structure of the high-speed permanent magnet motor with a sinusoidal magnetomotive force distribution law of the present invention;

[0018] Figure 2 It is a schematic diagram of the structure of a sintered permanent magnet unit of a high-speed permanent magnet motor rotor having a sinusoidal magnetomotive force distribution law according to the present invention;

[0019] Figure 3 It is a schematic diagram of the structure of the magnetic powder film and carbon fiber composite unit of the rotor of the high-speed permanent magnet motor with nearly sinusoidal magnetomotive force;

[0020] Figure 4 It is a schematic diagram of the structure of the magnetic powder film and carbon fiber composite subunit of the high-speed permanent magnet motor rotor with sinusoidal magnetomotive force distribution law of the present invention;

[0021] Figure 5 It is a schematic diagram of the rotor sleeve structure of the high-speed permanent magnet motor rotor with a sinusoidal magnetomotive force distribution law of the present invention;

[0022] Figure 6 It is a schematic diagram of the overall assembly structure of the high-speed permanent magnet motor rotor with a sinusoidal magnetomotive force distribution law of the present invention;

[0023] 1-rotating shaft, 2-sintered permanent magnet unit, 3-magnetic powder film and carbon fiber composite unit, 4-rotor sleeve, 5-sintered permanent magnet block, 6-sintered permanent magnet block gap, 7a-carbon fiber layer I, 7b-carbon fiber layer II, 7c-carbon fiber layer III, 8-magnetic powder film layer block, 9-film layer block. DETAILED DESCRIPTION

[0024] The present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0025] like Figure 1 , Figure 5 and Figure 6 As shown, a high-speed permanent magnet motor rotor with a sinusoidal magnetomotive force distribution law comprises a rotating shaft 1, a sintered permanent magnet unit 2, a magnetic powder film and carbon fiber composite unit 3 and a rotor sleeve 4; the rotating shaft 1 is located at the innermost side of the high-speed permanent magnet motor rotor, the outer side of the rotating shaft 1 is coaxially sleeved with the sintered permanent magnet unit 2, the outer side of the sintered permanent magnet unit 2 is wound with the magnetic powder film and carbon fiber composite unit 3 by interference fit, and during the winding process, it is ensured that the geometric center line of the magnetic powder film and the magnetic powder film layer block 8 in the carbon fiber composite subunit constituting the magnetic powder film and carbon fiber composite unit 3 coincides with the geometric center line of the sintered permanent magnet block 5, the outer side of the magnetic powder film and carbon fiber composite unit 3 is provided with a rotor sleeve 4 located at the outermost side of the high-speed permanent magnet motor rotor, and the rotor sleeve 4 is wound on the outer side of the magnetic powder film and carbon fiber composite unit 3 by applying tensile stress, and the rotor sleeve 4 is composed of five layers of carbon fiber layer III7c;

[0026] like Figure 3 and Figure 4As shown, the magnetic powder film and carbon fiber composite unit 3 is composed of thirty-three magnetic powder film and carbon fiber composite sub-units, and each magnetic powder film and carbon fiber composite sub-unit has the same structure, and is composed of a magnetic powder film layer block 8, a film layer block 9 and a carbon fiber layer II 7b; due to the discontinuous distribution of magnetic powder in the magnetic powder film layer block 8, the non-conductivity of the film and the shielding effect of the magnetic powder film and carbon fiber composite unit 3 on high-frequency electromagnetic waves, compared with the traditional high-speed permanent magnet motor rotor, the high-speed permanent magnet motor rotor of the present invention can effectively reduce the eddy current loss in the rotor; in addition, since the magnetic powder film and carbon fiber composite unit 3 contains a large amount of carbon fibers, and the magnetic material in the magnetic powder film is in a magnetic powder state without concentrated stress, the high-speed permanent magnet motor rotor of the present invention can effectively improve the mechanical strength of the rotor; the magnetic powder film and carbon fiber composite unit 3 The inner layer of the fiber composite subunit is composed of a magnetic powder film layer block 8 and a film layer block 9, and adjacent magnetic powder film layer blocks 8 are connected by the film layer blocks, and the outer layer is composed of a carbon fiber layer II 7b. The number of magnetic powder film layer blocks 8 and film layer blocks 9 is the same, and both are equal to the number of sintered permanent magnet blocks 5; the pole arc coefficient of the magnetic powder film layer block 8 decreases with the increase of the radius of the magnetic powder film and carbon fiber composite subunit, and the pole arc coefficient of the film layer block 9 increases with the increase of the radius of the magnetic powder film and carbon fiber composite subunit, and the sum of the pole arc coefficient of the magnetic powder film layer block 8 and the pole arc coefficient of the film layer block 9 is always 1. This structural design can make the magnetomotive force of the high-speed permanent magnet motor rotor of the present invention have a high sinusoidality, and then the sinusoidality of the air gap magnetic field is high, thereby reducing the high-order harmonic content in the high-speed permanent magnet motor. The magnetic powder film layer block 8 is formed by uniformly mixing neodymium iron boron (NdFeB) magnetic powder and epoxy resin in a ratio of 7:3 and then curing; the film layer block 9 is formed by curing epoxy resin; the magnetic powder film layer block 8 and the film layer block 9 have the same thickness, and the single layer thickness is 0.25mm, and the single layer thickness of the magnetic powder film and carbon fiber composite subunit is 0.4mm.

[0027] like Figure 2As shown, the sintered permanent magnet unit 2 is composed of a sintered permanent magnet block 5, a sintered permanent magnet block gap 6, a ferrite and carbon fiber layer Ⅰ7a; the sintered permanent magnet blocks 5 symmetrically arranged in pairs are directly adhered to the outer surface of the rotating shaft 1 to minimize the rotation radius of the sintered permanent magnet block 5, thereby minimizing the centrifugal force during its high-speed rotation; the sintered permanent magnet block 5 has a uniform thickness in the axial and circumferential directions and a pole arc coefficient less than 1. Since the remanent magnetic density of the sintered permanent magnet block 5 is large, it can provide a large excitation magnetomotive force for the rotor, thereby ensuring that the motor has a high output power density; the gap formed between adjacent sintered permanent magnet blocks 5 of different polarities is the sintered permanent magnet block gap 6, and in the sintered permanent magnet block gap 6 is filled with ferrite; filling ferrite in the gap 6 of the sintered permanent magnet block can not only enhance the excitation magnetic field of the rotor, but also absorb the deformation stress of the sintered permanent magnet block 5, thereby reducing the risk of excessive local stress at the edge of the sintered permanent magnet block 5 due to temperature or high speed; the carbon fiber layer Ⅰ7a is wound on the outside of the sintered permanent magnet block 5 and the gap 6 of the sintered permanent magnet block by applying tensile stress, and the number of layers of the carbon fiber layer Ⅰ7a is 3, and the winding thickness is 0.45mm; the carbon fiber layer Ⅰ7a can provide pre-compression stress for the sintered permanent magnet block 5, which can ensure that it is basically not subjected to tensile stress when the rotor runs at high speed, thereby avoiding the sintered permanent magnet block 5 from being damaged due to excessive tensile stress when the rotor rotates at high speed.

[0028] The rotating shaft 1 is a magnetic shaft, made of 40CrNiMoA material with good magnetic conductivity; the sintered permanent magnet block 5 is made of neodymium iron boron (NdFeB) permanent magnet with high remanence density; the carbon fiber layer is made of T700 carbon fiber with good tensile strength.

[0029] The high-speed permanent magnet motor rotor of the present invention is integrally magnetized by a pulsed strong magnetic field generating device composed of a capacitor bank, a thyristor, a charge and discharge control circuit and a magnetizing head (or a magnetizing coil), thereby forming a plurality of even-numbered poles.

[0030] A method for manufacturing a high-speed permanent magnet motor rotor having a sinusoidal magnetomotive force distribution law comprises the following steps:

[0031] Step 1, uniformly mix NdFeB magnetic powder and epoxy resin at a ratio of 7:3 and solidify to form a magnetic powder film layer block 8; solidify the epoxy resin to form a film layer block 9, connect the magnetic powder film layer block 8 and the film layer block 9 end to end, and wind a carbon fiber layer II 7b on the outside thereof to form a magnetic powder film and carbon fiber composite subunit;

[0032] Step 2, stick the sintered permanent magnet blocks 5 symmetrically arranged in pairs to the outer circumferential surface of the rotating shaft 1; fill ferrite in the gap between the sintered permanent magnet blocks formed by adjacent sintered permanent magnet blocks 5, the ferrite and the sintered permanent magnet blocks 5 together form an annular body, and wind the carbon fiber layer I7a on the outside of the annular body by applying tensile stress; the magnetic powder film and the carbon fiber composite sub-unit prepared in step 1 are successively wound on the outside of the carbon fiber layer I7a through interference fit, and during the winding process, it is necessary to ensure that the geometric center line of the magnetic powder film layer block 8 in the magnetic powder film and the carbon fiber composite sub-unit coincides with the geometric center line of the sintered permanent magnet block 5, and the carbon fiber layer III7c is wound on the outside of the magnetic powder film and carbon fiber composite unit 3 by applying tensile stress, and the installation is completed.

Claims

1. A high-speed permanent magnet motor rotor with a sinusoidal magnetomotive force distribution law, characterized in that: It comprises a rotating shaft, a sintered permanent magnet unit, a magnetic powder film and carbon fiber composite unit and a rotor sleeve; the rotating shaft is located at the innermost side of the high-speed permanent magnet motor rotor, the outer side of the rotating shaft is coaxially sleeved with a sintered permanent magnet unit, the outer side of the sintered permanent magnet unit is coaxially sleeved with a magnetic powder film and carbon fiber composite unit, the outer side of the magnetic powder film and carbon fiber composite unit is provided with a rotor sleeve, and the rotor sleeve is located at the outermost side of the high-speed permanent magnet motor rotor and is composed of multiple carbon fiber layers III; The magnetic powder film and carbon fiber composite unit is composed of a plurality of magnetic powder film and carbon fiber composite sub-units, and each magnetic powder film and carbon fiber composite sub-unit has the same structure, and is composed of a magnetic powder film layer block, a film layer block and a carbon fiber layer II; the inner layer of the magnetic powder film and carbon fiber composite sub-unit is composed of a magnetic powder film layer block and a film layer block, and the outer layer is composed of a carbon fiber layer II, and the outer layer is arranged outside the inner layer; the magnetic powder film layer block is formed by uniformly mixing magnetic powder and epoxy resin in a certain proportion and then curing; The number of the magnetic powder film layer blocks and the film layer blocks is the same and equal to the number of the sintered permanent magnet blocks; the pole arc coefficient of the magnetic powder film layer blocks decreases with the increase of the radius of the magnetic powder film and carbon fiber composite subunit, and the pole arc coefficient of the film layer blocks increases with the increase of the radius of the magnetic powder film and carbon fiber composite subunit, and the sum of the pole arc coefficient of the magnetic powder film layer blocks and the pole arc coefficient of the film layer blocks is always 1; the content of NdFeB magnetic powder in the magnetic powder film layer blocks is ≥60%; the film layer blocks are cured by epoxy resin; the thickness of the magnetic powder film layer blocks is the same as that of the film layer blocks, and the single layer is 0.2mm-0.25mm, and the single layer thickness of the magnetic powder film and carbon fiber composite subunit is ≤0.4mm; The sintered permanent magnet unit comprises a sintered permanent magnet block, a sintered permanent magnet block gap and a carbon fiber layer I. The sintered permanent magnet blocks are symmetrically arranged in pairs, the sintered permanent magnet blocks have uniform thickness in the axial and circumferential directions, and the pole arc coefficient is less than 1; the gap formed between adjacent sintered permanent magnets is a sintered permanent magnet gap, and ferrite is filled in the sintered permanent magnet block gap; The outer sides of the sintered permanent magnet block and the ferrite are wound with a carbon fiber layer I, and the number of layers of the carbon fiber layer I is ≤4 layers, and the winding thickness is ≤0.8 mm.

2. The high-speed permanent magnet motor rotor with a sinusoidal magnetomotive force distribution law according to claim 1 is characterized in that: The number of carbon fiber layers III constituting the rotor sleeve is ≤10.

3. The high-speed permanent magnet motor rotor with a sinusoidal magnetomotive force distribution law according to claim 1 is characterized in that: The sintered permanent magnet block adopts NdFeB permanent magnet with high remanence density; the carbon fiber layer I, carbon fiber layer II and carbon fiber layer III are all made of carbon fiber with good tensile performance; the rotating shaft is a magnetic shaft, which is made of material with good magnetic conductivity.

4. The method for manufacturing a high-speed permanent magnet motor rotor having a sinusoidal magnetomotive force distribution rule according to claim 1, characterized in that: The following steps are involved: Step 1, uniformly mix magnetic powder and epoxy resin in a certain ratio and solidify them to form a magnetic powder film layer block; solidify the epoxy resin to form a film layer block, connect the magnetic powder film layer block and the film layer block end to end, and wind the carbon fiber layer II on the outside thereof to form a magnetic powder film and carbon fiber composite subunit; Step 2, sticking the sintered permanent magnet blocks symmetrically arranged in pairs onto the outer circumferential surface of the rotating shaft; filling ferrite in the gap between the sintered permanent magnet blocks formed by adjacent sintered permanent magnet blocks, the ferrite and the sintered permanent magnet blocks together form an annular body, and winding the carbon fiber layer I on the outside of the annular body by applying tensile stress; the magnetic powder film and the carbon fiber composite sub-unit prepared in step 1 are successively wound on the outside of the carbon fiber layer I through interference fit, and during the winding process, it is necessary to ensure that the geometric center line of the magnetic powder film layer block in the magnetic powder film and the carbon fiber composite sub-unit coincides with the geometric center line of the sintered permanent magnet block, and the carbon fiber layer III is wound on the outside of the magnetic powder film and the carbon fiber composite unit by applying tensile stress, and the installation is completed.

Images