RU2845615C1 - Hybrid magnetic element for electric machine rotor resistant to irreversible demagnetization under overheating conditions - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: hybrid magnetic element for the rotor of an electric machine is made in the form of a package of glued together parts from magnetically hard and magnetically soft materials, the number and sequence of arrangement of which in the direction perpendicular to the polar axis of the magnetic element, the chemical composition of the material of the parts, coercive force index and glue parameters are selected to ensure operation of the electric machine rotor in possible overheating zones of the magnetic element preventing irreversible demagnetisation. Electric machine rotor contains the above hybrid magnetic elements, at the same time parts made of materials with demagnetization temperature that exceeds overheating temperature of rotor magnetic element under conditions of electric machine operation, are arranged in identified zones of possible rotor overheating.

EFFECT: improving operating efficiency of synchronous electric drives based on permanent magnets by minimizing the effect of thermal heating on magnetic characteristics of permanent magnets.

10 cl, 8 dwg, 1 tbl

Description

Field of technology to which the invention relates

The invention relates to electrical engineering and can be used to manufacture magnetic elements for synchronous electric drives based on permanent magnets.

State of the art

It is known that synchronous electric drives based on permanent magnets (SEPM) have a number of technical advantages, namely, significantly smaller weight and size characteristics and higher efficiency. However, with an increase in temperature under the influence of the magnetic field created by the stator windings, demagnetization of the permanent magnets (PM) is possible. Depending on the position of the load line (dashed line in Fig. 1) and the demagnetizing factor of the permanent magnet (L/D ratio), the temperature range of increasing demagnetization probability can change (see C.H. Chen. Engineering magnetic materials and their applications, Course MAT-512, University of Dayton. 2006-2010). The critical factor is the degree of proximity to the so-called "knee" (located in the region of 6-9 kOe), in the region of which spontaneous complete or partial demagnetization of the PM can occur. Thus, the models shown in Fig. 1 data for the NdFeB33 PM (hereinafter in the description text and in the examples of execution, the number next to the permanent magnet brand, both NdFeB and SmCo, means the value of the maximum energy product of the permanent magnet, measured in MGE), allow us to conclude that this PM can operate at a temperature of up to 100°C with a demagnetization factor of 0.2 and at a temperature of 175°C with a demagnetization factor of 2.0. As a rule, an increase in the operating temperature is achieved by adding dysprosium (Dy) or terbium (Tb) - rare earth elements with high magnetic anisotropy constants, which, however, sharply increases the costs of manufacturing electric drives.

It seems relevant to search for ways to increase the operating temperature of the PM, since the constant reduction in the size of modern EPCM, as well as the increase in current density (torque is directly proportional to current density) leads to an increase in power density and greater Joule losses per unit volume. This leads to the need to remove more heat per unit time, which is difficult with the smallest volume of the EPCM (smaller heat sink surface area), which ultimately causes an increase in the temperature of the rotor and the PM located on it.

Improvements in rotor design using Dy-free NdFeB PMs are known. The article Irreversible Demagnetization Improvement Process of Hybrid Traction Motors with Dy-Free Magnets / Machines 2023, 11 (1), 4; doi.org/10.3390/machines11010004 describes a process for improving irreversible demagnetization by improving the design - changing the distance between the air holes in the rotor magnetic circuit, which shifts the region where irreversible demagnetization occurs to the region with a low back EMF contribution. Although the magnet devoid of rare earth elements has a high probability of irreversible demagnetization at high temperatures due to its low coercivity, this article proposes a process to counteract irreversible demagnetization in order to compensate for this drawback. This process analyzes the back EMF (electromotive force) contribution of the PM using the flux linkage equation. Then the place of irreversible demagnetization moves to a position with a low contribution to the reverse electromotive force. That is, the degree of irreversible demagnetization can be reduced if it occurs where the contribution of the magnet's reverse EMF is small. The distance between the air holes in the rotor magnetic circuit is selected structurally so that the PM without dysprosium is less demagnetized.

A method for estimating the PM temperature in permanent magnet synchronous machines using search coils is described (Yuan Cheng et al. "Magnet temperature estimation of permanent magnet synchronous motor using search coils" - 25th International Conference on Electrical Machines and Systems (ICEMS), 2022; DOI: 10.1109/ICEMS56177.2022.9983044). This makes it possible to replace direct temperature measurements with indirect ones based on the linear dependence of the motor flux linkage and the PM temperature, but with high accuracy. Options using such measurements are described (CN 114928290 A, published 19.08.2022; CN 114928289 A, published 19.08.2022; JP 2022116488 A, published 10.08.2022). Various practical implementations of the PM rotors themselves are described, allowing to reduce the demagnetizing factor and, accordingly, increase the efficiency of generators.

A design of hybrid PMs is known, where each PM consists of several magnetic materials with different magnetic flux values (US 10714988 B2). The PM contains a first magnetic material; and a second magnetic material different from the first magnetic material. In this case, the polar axis of the first magnetic material is parallel to the polar axis of the second magnetic material. The saturation magnetization (MS), magnetic anisotropy (Ku), temperature coefficient (CT) of magnetization, CT of the coercive force or Curie temperature ( _TC ) is higher for the second magnetic material than for the first material. The volume of the second magnetic material is less than or equal to the volume of the first magnetic material. The first magnetic material is selected from the group consisting of: alnico, ferrite, a magnetic material based on a rare earth metal, a magnetic material based on manganese, a magnetic material based on a transition metal and platinum or iron nitride (FeN). The second magnetic material is selected from a group comprising: alnico, ferrite, a rare earth metal based material, a manganese based material, a transition metal based magnetic material and platinum or Fe-N. The second PM has a higher magnetic flux density compared to the first magnetic material.

The article (Dapeng Wang et al. Exchange-coupled nanoscale SmCo/NdFeB hybrid magnets - Journal of Magnetism and Magnetic Materials Volume 324, Issue 18, September 2012, Pages 2836-2839; DOI: 10.1016/j.jmmm.2012.04.018) describes the advantages of hybrid NdFeB/SmCo magnets over single-phase ones. A method for producing hybrid magnets is described, which consists in annealing a finely dispersed powder mixture of NdFeB and Sm-Co in a vacuum and under pressure. The size of the powder particles did not exceed 20 nm. As a result, extremely low values of the coercive force and BHmax were obtained at the level of 12-14 MGOe, which do not allow the use of composites in real highly loaded electric drives with high torque density. It was found that such an approach does not allow locally increasing the value of Hcj at a given location of the PM subject to large demagnetizing fields.

The closest to the claimed solution is the invention according to the application CN 105449967 A - Combined magnetic pole built-in radial direction V type permanent magnet synchronous motor, published on 30.03.2016 - prototype), which describes the implementation of a V-type PM with a combined magnetic pole in the radial direction for a PMSM. The magnetic field of the air gap of the PMSM has additional harmonics, which can cause irreversible demagnetization, therefore the magnetic pole of the rotor has a single-layer or multilayer nested V-shaped PM structure; the magnetic pole of the rotor contains two PM poles made of rare earth metals and two poles made of ferrite. The directions of magnetization coincide. Such a combination can bring the shape of the flux density wave in the air gap closer to a sine wave and reduce the content of harmonics in the magnetic field of the air gap.

The disadvantage of this solution is that it does not include means to prevent irreversible demagnetization of the PM due to heating and overheating during operation of the electric machine.

The present invention is aimed at solving the problem of increasing the efficiency of the functioning of the PM by eliminating/reducing the effect of temperature heating on the magnetic characteristics of the PM during operation.

Disclosure of invention

The technical result is an increase in the efficiency of the functioning of the EPMS by minimizing the effect of temperature heating on the magnetic characteristics of the PM during operation.

The patented solution is a formed hybrid magnetic element for the SEPM, containing combined poles made of magnetic materials resistant to irreversible demagnetization.

The technical result is achieved by producing a hybrid magnetic element for the rotor of an electric machine and a rotor containing the said magnetic elements.

Zones of possible overheating of the rotor magnetic element causing irreversible demagnetization at the operating temperatures of the electric machine rotor are preliminarily identified. The rotor magnetic element is made in the form of a package of glued together parts made of ferromagnetic materials, the number and sequence of arrangement of which in the direction perpendicular to the polar axis of the magnetic element, the chemical composition of the material of the parts, the coercive force index and the parameters of the glue are selected based on the condition of ensuring the operation of the electric machine rotor in zones of possible overheating, and in the identified zones of possible overheating, parts made of materials having a demagnetization temperature exceeding the overheating temperature of the rotor magnetic element under the operating conditions of the electric machine are located.

In one embodiment of the invention, the size of the parts in the package, including the thickness, direction of magnetization, maximum energy product, residual induction, saturation magnetization, coercive force and temperature coefficients of these quantities, as well as losses due to magnetization reversal, are selected based on the condition of ensuring the operation of the rotor of the electric machine in areas of possible overheating of the magnetic element, preventing irreversible demagnetization, and ensuring the required operating characteristics of the electric machine.

Potential overheating zones in the body of the rotor magnetic element can be determined experimentally or by means of modeling.

The number of parts is 2-10 with their thickness from 0.1 to 10 mm in the gluing direction. The gluing of the plates is carried out using compounds containing microparticles of soft magnetic materials. Parts made of ferromagnetic materials include sintered rare-earth PM NdFeB and SmCo (the exact chemical composition of these permanent magnets can contain up to 10 different chemical elements and varies depending on the manufacturer), ferrites, hard magnetic plastic magnets or composites based on them.

In one embodiment of the invention, the stack is formed from parts and has a layered structure, for example: NdFeB50H-SmCo35-NdFeB50H-SmCo35-NdFeB50H, or NdFeB-SmCo, or FeN-SmCo, or SmCo32-N42H, or SmCo35-N42SH-SmCo35-N42SH-SmCo35-N42SH-SmCo35-N42SH-SmCo35-N42SH. In these stacks, the thickness of the part made of NdFeB50H is significantly less (at least 2 times) than the thickness of the part made of SmCo35.

The best result is achieved when implementing the invention with a layered structure, in which the outer parts of the stack are made of sintered rare earth permanent magnets of the SmCo brand, for example: SmCo35-NdFeB50H-SmCo35 (the letter H means that the NdFeB PM has an operating temperature of 120 ° C), or SmCo35-NdFeB50H-SmCo35-NdFeB50H-SmCo35, or SmCo35-NdFeB50H-SmCo35-NdFeB50H-SmCo35-NdFeB50H-SmCo35, or SmCo-FeN-SmCo (in particular, a composition with a structure of the Sm2Co17-Fe16N2-Sm2Co17 type), or SmCo32-NdFeB42H-SmCo32, or SmCo33-NdFeB50H-SmCo33, or SmCo33-Fe16N2-SmCo33, or SmCo33-NdFeB50H-SmCo33-NdFeB50H-SmCo33, or SmCo33-NdFeB50H-SmCo33-NdFeB50H-SmCo33-NdFeB50H-SmCo33, or SmCo35-NdFeB42SH-SmCo33-NdFeB42H-SmCo32-NdFeB42SH-SmCo33-N42SH-SmCo35.

Thus, SmCo35, SmCo32, SmCo33 magnets, as well as other brands, can be used as parts of SmCo magnets (see, for example, https://www.amtc.ru/upload/smco.pdf; https://www.arnoldmagnetics.com/products/recoma-samarium-cobalt-magnets/; https://www.chinahpmg.com/pr.jsp?_jcp=3_3#_pp=120_0).

The composition of SmCo magnet parts may include various chemical elements, for example, PM Sm2Co17: Sm (Cobal.Fe 0.35 Cu0.06 Zr 0.018) 7.8: (or in weight %: Sm - 24.72%, Co - 43.22%, Fe - 25.06%, Zr - 2.11%, Cu - 4.89%), which provides properties at room temperature at the level of (BH) = 35 MGOe (282 kJ/ ^m3 ) at Br = 1.225 T and Hcj = 1580 kA/m (Y. Horiuchi et al., Journal of applied physics 117, 17C704 (2015)). In the text of the present description of the invention, permanent magnets with similar magnetic characteristics are designated as SmCo35. In this case, the iron content can vary from 15 to 20 wt.%, which provides the following magnetic properties at 19% Br = 1.2 T, Hcj = 2380 kA/m, (BH)max = 262 kJ/ ^m3 (about 33 MGOe) (M. Duerrschnabel et al., DOI: 10.1038/s41467-017-00059-9). Permanent magnets with similar magnetic characteristics are designated as SmCo33. The permanent magnet Sm25Co42Fe26Cu5Zr2 (wt.%) with an iron content of 26 wt.% has a value of Br = 1.24 T (Mingyao Hu et al., DOI: 10.1002/adfm.202400305). In this case, depending on the manufacturer, the cobalt content in the magnet composition may vary from 42 to 51 wt.%. Permanent SmCo magnets with a high iron content from 19 to 26 wt.% and an increased Br>1.2 T value are preferred for use in the hybrid glued magnet claimed in the present invention.

The arrangement of the parts in the package is preferable in such a way that the direction of magnetization (texture) of the outer permanent magnets SmCo is located perpendicular to the direction of magnetization (texture) of the parts made of PM NdFeB. In the case of a package of 5 or more layers, the central PM SmCo is made multilayer, in particular, from two layers with the direction of magnetization of the said layers differing by 180°.

Reducing demagnetization during the heating process ensures a reduction in the overall (total) temperature coefficients for the coercive force Hcj and residual induction Br of the hybrid magnet during operation.

Brief description of the drawings

The essence of the invention is explained in the figures.

Fig. 1 - demagnetization characteristics of the SEPM;

Fig. 2-4 - diagram of a hybrid magnetic element with options for placing parts in overheating zones;

Fig. 5 - SEPM with different types of magnets on the rotor:

a) with solid magnets,

b) with hybrid magnets SmCo35-NdFeB50H-SmCo35,

c) with hybrid magnets SmCo35-NdFeB50H-SmCo35-N50dFeBH-SmCo35,

d) with hybrid magnets NdFeB50H-SmCo35-NdFeB50H-SmCo35-NdFeB50H;

Fig. 6 - graphs of the dependence of the electromagnetic moment on the temperature of the magnets;

Fig. 7, 8 - graphs of the dependence of the magnetic flux linkages on temperature and

duration of heating.

The following positions are indicated in the drawings: 1 - stator, 2 - armature winding, 3 - rotor yoke, 4 - solid magnet, 5 - SmCo35-N50H-SmCo35 hybrid magnet, 6 - SmCo35-NdFeB50H-SmCo35-NdFeB50H-SmCo35 hybrid magnet, 7 - NdFeB50H-SmCo35-NdFeB50H-SmCo35-NdFeB50H, 8 - temperature dependence of overheating zones along the length of the magnetic element, 9, 10 - overheating zones, 11 - package parts, 12, 13 - package parts having a higher demagnetization temperature.

Implementation of the invention

The diagram of the hybrid magnetic element with variants of the placement of parts in the overheating zones is shown in Fig. 2-4. Thus, parts 11 can be made of sintered NdFeB, SmCo rare earth elements, ferrites, hard magnetic plastic magnets or composites based on them. Parts 12, 13, having a higher demagnetization temperature, are made of higher temperature magnetic materials, namely NdFeB, SmCo, rare earth elements.

The quantitative assessment of the thermal stability of the proposed hybrid magnets is shown in Fig. 7, 8. Three magnets were selected for comparison: 1 - a neodymium magnet of the NdFeB42AH brand (with an operating temperature of up to 230°C); 2 - a neodymium magnet of the N42H brand; 3 - a hybrid magnet assembled from magnets of the NdFeB42H and S28G brands (SmCo28-NdFeB42H-SmCo28). The overall dimensions of the tested magnets are the same and are 21×21×3.7 mm.

The testing methodology consisted of 6 points:

1. The magnets were magnetized to saturation in a pulsed magnetic field with an amplitude of 5 T.

2. The magnetic flux linkage with the Helmholtz coil Ψ0 of the magnets after point 1 was measured.

3. The magnets were placed in a furnace as part of a closed magnetic circuit.

4. The magnets were kept in the furnace at a temperature tn for 5 minutes, after which they were removed from the furnace and kept at normal temperature to cool to the ambient temperature.

5. The flux linkage after heating Ψn-5 was measured.

6. The magnets were re-magnetized to saturation, and steps 2-5 were repeated after holding for 10 min, Ψn-10 was measured.

As a result of the tests it was determined:

1. When heated rapidly, NdFeB42H magnets and the SmCo28-NdFeB42H-SmCo28 hybrid magnet behave almost identically;

2. The hybrid magnet has a less abrupt drop in flux, particularly when heated to 240°C;

3. The magnetic flux of the hybrid magnet after heating is 30% greater than that of the NdFeB42H magnet.

It follows from the above that in highly loaded ECMs operating for a long time at high temperatures, the use of hybrid magnets is most relevant.

The gluing of the plates is carried out using compounds with a relative magnetic permeability 2-3 times greater than the magnetic permeability of a vacuum, containing microparticles of soft magnetic materials. The parts can be made of a composite including hard magnetic materials, as well as isotropic and anisotropic electrical steels or soft magnetic plastics. The chemical composition is selected by calculation with subsequent experimental confirmation in such a way as to ensure the optimal required value of the temperature coefficients for the residual magnetic induction Br and the coercive force Hcj (see Fig. 7, 8). The traditional method assumes achieving minimum values of the temperature coefficients.

The claimed device assumes the possibility of using magnetic elements with controlled and predictable changes in temperature coefficients, thanks to control of the chemical composition of the components (see Table 1).

GOST 52956-2008 provides limitations on such temperature dependences of magnetic parameters of materials as residual magnetic induction Br and coercive force by magnetization Hcj. Relative changes in parameters in the temperature range of 293 K - 373 K are fixed as ΔBr×100/(Br×ΔТ) from -0.12 to -0.08%/K and ΔHcj×100/(Hcj×ΔТ) from -0.59 to -0.45%/K, respectively. Traditionally, this is done to avoid significant demagnetization of the PM and to ensure the stability of the operating characteristics of an electric machine with a PM on the rotor. However, to ensure this level of temperature coefficient values, it is impossible to use mischmetal PrNd, and it is necessary to add more expensive metallic Nd and even more expensive metallic dysprosium. Since PM are one of the most expensive components of an electric machine, this significantly limits the scope of application of SEPM. At the same time, with the development of high-speed machines, additional technical difficulties have appeared. The inability to control the value of these temperature coefficients leads to difficulties in demagnetizing rotors at high speeds, increases the value of the back-EMF and complicates the control of the electric machine.

Thus, precise regulation of the value of these temperature coefficients is necessary, which is achieved by the proposed technical solution.

As an example of implementation, a model of the SEPM is considered, in which the PM is located on the outer rotor.

The model takes into account the temperature-dependent properties of permanent magnets of the NdFeB50H and SmCo35 brands.

Fig. 5a shows the models of the SEPM with solid magnets, and Fig. 5b, 5c, 5d - with hybrid magnets 5, 6 and 7, respectively, where 5 is the SmCo35-N50H-SmCo35 hybrid magnet, 6 is the SmCo35-NdFeB50H-SmCo35-NdFeB50H-SmCo35 hybrid magnet, 7 is the NdFeB50H-SmCo35-NdFeB50H-SmCo35-NdFeB50H hybrid magnet. The outer diameter of the SEPM is 280 mm, the axial length is 65 mm, the number of teeth is 54, and the number of poles is 48. The winding is fractional-tooth, the number of slots per pole and phase is 3/8, the number of turns per tooth is 10, connected in a star. The transverse dimensions of solid magnets are 4×12 mm (Fig. 5 a); hybrid magnets Fig. 5: b) 4×4 mm, c) and d) 4×2.4 mm. Load current is 550 A, lead angle is 10 electrical degrees, frequency is 373.2 Hz.

Since the SEPM has symmetry, only 1/6 of the entire circumference of the models is shown in Fig. 5. Electromagnetic calculations were performed using the finite element method, with symmetry boundary conditions specified on the lateral boundaries and Dirichlet conditions corresponding to a zero value of the vector magnetic potential on the outer boundaries.

For each model, the electromagnetic torque was calculated, with the load mode set to be the same for all cases. The calculations were performed at magnet temperatures of 20°C, 120°C and 200°C. As a result, the torque dependences on magnet temperature were obtained for each rotor variant (Fig. 6).

It follows from the graphs that in the temperature range of 120°C above the operating temperature of NdFeB50H magnets, rotors with hybrid magnets provide a higher torque value. For example, the torque of the EPDM with Sm-Nd-Sm hybrid magnets provides a torque value 24% higher than that of the EPDM with N50H magnets. In the low temperature range of 20-120°C, the EPDM with hybrid magnets provides a torque value 5-8% higher than that of the EPDM with SmCo35 magnets. The described positive effect is achieved due to the fact that SmCo35 magnets are much more resistant to demagnetization at high temperatures, compared to NdFeB50H magnets.

Fig. 7, 8 - graphs of the dependence of magnet flux linkages on temperature and heating duration. It is evident that the hybrid magnet NdFeB42H/S28G provides the required level of temperature dependence of flux linkage for 5 and 10 min when heated to 240°C.

Below are examples of hybrid magnets for the EPSM, made in accordance with this invention. In particular, neodymium magnets (NdFeB) of the following brands were used as components in the package: NdFeB50H (working temperature 120°C), NdFeB42H, NdFeB42SH (working temperature 140°C), as well as samarium-cobalt magnets of the brands SmCo35, SmCo33, SmCo32 (working temperature 350°C).

EXAMPLE 1

1. Dimensions of parts: length, width, height (thickness) 2×21×2 (mm).

2. Number of parts in the package - 3.

3. Composition of materials in the package: SmCo35-N50H-SmCo35.

4. Adhesive material: DELO® MONOPOX HT2999, bonding thickness - 15 µm. Bonding filler - microparticles of soft magnetic materials of the composition MnO, 8ZnO, 2Fe ₂ O ₄ , 20% vol.

5. The obtained characteristics of the hybrid magnet Br=1.26 T, Hcv=951 kA/m, Hcj=2035 kA/m, (BH)max=301 kJ/ ^m3 .

EXAMPLE 2

1. Dimensions of parts: length, width, height (thickness) 5×21×3 (mm).

2. Number of parts in the package - 5.

3. Composition of materials in the package: SmCo35-N50H-SmCo35-N50H-SmCo35.

4. Adhesive material: brand BT-25-200 JCN B 6-06-5100-96, bonding thickness 5-10 µm, bonding filler - microparticles of soft magnetic material Fe ₃ O ₄ , 25% vol.

5. Obtained characteristics of hybrid magnets at T=20°C, Br=1.22 T, Hcv=948 kA/m, Hcj=2030 kA/m, (BH)max=293 kJ/ ^m3 .

EXAMPLE 3

1. Dimensions of parts: length, width, height (thickness) 5×21×1.7 (mm).

2. Number of parts in the package - 5.

3. Composition of materials in the package: N50H-SmCo35-N50H-SmCo35-N50H.

4. Adhesive material: DELO® MONOPOX HT2999 brand, bonding thickness 10 µm, adhesive filler - absent.

5. The obtained characteristics of hybrid magnets Br=1.18 T, Hcv=891 kA/m, Hcj=1991 kA/m, (BH)max=278 kJ/ ^m3 .

EXAMPLE 4

1. Dimensions of parts: length, width, height (thickness) 1×10×1.5 (mm).

2. Number of parts in the package - 2.

3. Composition of materials in the package: SmCo32-N42H.

4. Adhesive material: DELO® MONOPOX HT2999, bonding thickness 10 µm, bonding filler - microparticles of soft magnetic materials: MnO, 8ZnO, 2Fe ₂ O ₄ , 20% vol.

5. The obtained characteristics of hybrid magnets Br=1.18 T, Hcv=910 kA/m, Hcj=1790 kA/m, (BH)max=265 kJ/ ^m3 .

EXAMPLE 5

1. Dimensions of parts: length, width, height (thickness) 5×10×5 (mm).

2. Number of parts in the package - 10.

3. Composition of materials in the package:

SmCo35-N42SH-SmCo35-N42SH-SmCo35-N42SH-SmCo35-N42SH-SmCo35-N42SH.

4. Adhesive material: DELO® MONOPOX HT2999, bonding thickness 12 µm, bonding filler - microparticles of soft magnetic materials, MnO, 85ZnO, 15Fe ₂ O ₄ , 20% vol.

5. The obtained characteristics of hybrid magnets Br=1.20 T, Hcv=950 kA/m, Hcj=2010 kA/m, (BH)max=275 kJ/ ^m3 .

EXAMPLE 6

1. Dimensions of parts: length, width, height (thickness) 5×21×2 (mm).

2. Number of parts in the package - 3.

3. Composition of materials in the package: SmCo33-NdFeB50H-SmCo33.

4. Adhesive material: DELO® MONOPOX HT2999, bonding thickness - 15 µm. Adhesive filler - microparticles of soft magnetic materials of the composition MnO, 8ZnO, 2Fe ₂ O ₄ , 20% vol.

5. The obtained characteristics of the hybrid magnet Br=1.23 T, Hcv=950 kA/m, Hcj=2055 kA/m, (BH)max=285 kJ/ ^m3 .

6. Coating - Ni/Cu/Ni.

EXAMPLE 7

1. Dimensions of parts: length, width, height (thickness) 5×21×2.5 (mm).

2. Number of parts in the package - 5.

3. Composition of materials in the package: SmCo33-NdFeB50H-SmCo33-NdFeB50H-SmCo33.

4. Adhesive material: brand BT-25-200 JCN B 6-06-5100-96, bonding thickness 5-10 µm, bonding filler - microparticles of soft magnetic material Fe ₃ O ₄ , 25% vol.

5. Obtained characteristics of hybrid magnets at T=20°C, Br=1.22 T, Hcv=938 kA/m, Hcj=2061 kA/m, (BH)max=289 kJ/ ^m3 .

6. Coating - hard epoxy resin H6.

EXAMPLE 8

1. Dimensions of parts: length, width, height (thickness) 5×21×3 (mm).

2. Number of parts in the package - 7.

3. Composition of materials in the package: SmCo33-NdFeB50H-SmCo33-NdFeB50H-SmCo33-NdFeB50H- SmCo33.

4. Adhesive material: DELO® MONOPOX HT2999, bonding thickness 10 µm,

adhesive filler - absent.

5. The obtained characteristics of hybrid magnets Br=1.24 T, Hcv=930 kA/m, Hcj=2070 kA/m, (BH)max=293 kJ/ ^m3 .

6. Coating - Ni/Cu/Ni.

EXAMPLE 9

1. Dimensions of parts: length, width, height (thickness) 10×10×3 (mm).

2. Number of parts in the package - 3.

3. Composition of materials in the package: SmCo32-NdFeB42H- SmCo32.

4. Adhesive material: DELO® MONOPOX HT2999, bonding thickness 10 µm, bonding filler - microparticles of soft magnetic materials: MnO, 8ZnO, 2Fe ₂ O ₄ , 20% vol.

5. The obtained characteristics of hybrid magnets Br=1.18 T, Hcv=933 kA/m, Hcj=1882 kA/m, (BH)max=284 kJ/ ^m3 .

6. Coating - hard epoxy resin H6.

EXAMPLE 10

1. Dimensions of SmCo33 parts: length, width, height (thickness) 5×10×2 (mm).

Dimensions of SmCo32 parts: length, width, height (thickness) 5×10×2.5 (mm).

Dimensions of NdFeB42SH parts: length, width, height (thickness) 5×10×2.5 (mm).

Dimensions of NdFeB42H parts: length, width, height (thickness) 5×10×2 (mm).

2. Number of parts in the package - 9.

3. Composition of materials in the package:

SmCo35-NdFeB42SH-SmCo33-NdFeB42H-SmCo32-NdFeB42SH-SmCo33-N42SH-SmCo35.

4. Adhesive material: DELO® MONOPOX HT2999, bonding thickness 12 µm, bonding filler - microparticles of soft magnetic materials, MnO, 85ZnO, 15Fe ₂ O ₄ , 20% vol.

5. The obtained characteristics of hybrid magnets Br=1.21 T, Hcv=945 kA/m, Hcj=1850 kA/m, (BH)max=285 kJ/ ^m3 .

6. Coating - phosphating.

EXAMPLE 11

1. Dimensions of SmCo33 parts: length, width, height (thickness) 10×10×3 (mm).

Dimensions of Fe16N2 parts: length, width, height (thickness) 10×10×1 (mm).

2. Number of parts in the package - 3.

3. Composition of materials in the package: SmCo33-Fe16N2-SmCo33.

4. Adhesive material: DELO® MONOPOX HT2999, bonding thickness 10 µm.

5. The obtained characteristics of hybrid magnets Br=1.21 T, Hcv=912 kA/m, Hcj=1520 kA/m, (BH)max=262 kJ/ ^m3 .

6. Coating - phosphating.

Thus, based on the results of the given examples of the invention implementation, it follows that hybrid magnets make it possible to combine the positive qualities of NdFeB50H, SmCo35, SmCo33 and SmCo32 magnets and obtain an increase in the moment of the SEM in a wide temperature range, without using terbium and dysprosium.

Claims (10)

1. A hybrid magnetic element for an electric machine rotor, made of magnetic materials resistant to irreversible demagnetization, characterized in that the magnetic element is made in the form of a package of parts glued together from magnetically hard and magnetically soft materials, the number and sequence of which in the direction perpendicular to the polar axis of the magnetic element, the chemical composition of the material of the parts, the coercive force index and the parameters of the adhesive are selected based on the condition of ensuring the functioning of the electric machine rotor in areas of possible overheating of the magnetic element, preventing irreversible demagnetization. 2. A hybrid magnetic element according to claim 1, characterized in that the package of parts glued together, in which the size of the parts, including the thickness, direction of magnetization, indicators of the maximum energy product, residual induction, saturation magnetization, coercive force and temperature coefficients of these quantities, as well as losses due to magnetization reversal, are selected based on the condition of ensuring the functioning of the rotor of the electric machine in zones of possible overheating of the magnetic element, preventing irreversible demagnetization, and ensuring the required operating characteristics of the electric machine. 3. A hybrid magnetic element according to item 1, characterized in that the number of parts is 2-10 with their thickness from 0.1 to 10 mm in the gluing direction. 4. A hybrid magnetic element according to paragraph 1, characterized in that the parts are made in the form of plates that are glued together using compounds containing microparticles of soft magnetic materials. 5. A hybrid magnetic element according to claim 1, characterized in that the parts made of hard magnetic materials include sintered rare earth permanent magnets Fe16N2, ferrites, hard magnetic plastic magnets or composites based on them. 6. A hybrid magnetic element according to claim 1, characterized in that the external parts of the package are made of SmCo permanent magnets, wherein the direction of magnetization of the external (extreme) SmCo permanent magnets is located perpendicular to the direction of magnetization of the NdFeB permanent magnets, wherein when using a package of a hybrid magnetic element of 5 or more layers, one or more central permanent magnets (parts) of SmCo are made multilayer with the direction of magnetization of adjacent layers (in one part) differing by 180°. 7. A hybrid magnetic element according to claim 1, characterized in that the stack is formed from parts having a layered structure of grades selected from the following series: NdFeB50H-SmCo35-NdFeB50H-SmCo35-NdFeB50H, or NdFeB-SmCo, or FeN-SmCo, or SmCo32-N42H, or SmCo35-N42SH-SmCo35-N42SH-SmCo35-N42SH-SmCo35-N42SH-SmCo35-N42SH, wherein in these stacks the thickness of the part made of NdFeB50H is at least 2 times less than the thickness of the part made of SmCo. 8. A hybrid magnetic element according to claim 1, characterized in that the package is formed from parts having a layered structure of grades selected from the following series: SmCo35-NdFeB50H-SmCo35 or SmCo35-NdFeB50H-SmCo35-NdFeB50H-SmCo35. 9. A hybrid magnetic element according to claim 1, characterized in that the stack is formed from parts having a layered structure of grades selected from the following series: SmCo35-NdFeB50H-SmCo35-NdFeB50H-SmCo35-NdFeB50H-SmCo35, or SmCo-FeN-SmCo, or SmCo32-NdFeB42H-SmCo32, or SmCo33-NdFeB50H-SmCo33, or SmCo33-Fe16N2-SmCo33, or SmCo33-NdFeB50H-SmCo33-NdFeB50H-SmCo33, or SmCo33-NdFeB50H-SmCo33-NdFeB50H-SmCo33-NdFeB50H-SmCo33, or SmCo35-NdFeB42SH-SmCo33-NdFeB42H-SmCo32-NdFeB42SH-SmCo33-N42SH-SmCo35. 10. A rotor of an electric machine containing hybrid magnetic elements according to paragraph 1, made in the form of a package of parts glued together from magnetically hard and magnetically soft materials, the number and sequence of arrangement of which in the direction perpendicular to the polar axis of the magnetic element, the chemical composition of the material of the parts, the coercive force index and the parameters of the glue are selected based on the condition of ensuring the functioning of the rotor of the electric machine in zones of possible overheating of the magnetic element, preventing irreversible demagnetization, wherein the parts made of materials having a demagnetization temperature exceeding the overheating temperature of the magnetic element of the rotor under operating conditions of the electric machine are placed in the identified zones of possible overheating of the rotor.