Novel composite lamination structure for motor stator core

Abstract

The invention discloses a novel composite lamination structure for a motor stator core, which breaks through the traditional stator full lamination homogenization design thought, proposes an axial gradient composite structure, replaces the middle region of the lamination with FeSi-based nanocrystalline alloy, and retains the traditional silicon steel laminations in the regions at the two ends. According to the invention, the problem of low lamination coefficient caused by full lamination is effectively relieved, and meanwhile, the problem of high cost caused by full-disc material replacement is avoided. And moreover, the end magnetic load capacity is improved by utilizing the high Bs characteristic of the FeSi-based nanocrystalline alloy, so that the overall magnetic flux density is improved, meanwhile, the silicon steel laminations at the two end sections are reserved, the low eddy-current loss is maintained, and collaborative optimization of structure-performance is achieved.

Description

Technical Field

[0001] The present invention relates to a novel composite lamination structure for a motor stator core, belonging to the technical field of motor stator core manufacturing. Background Art

[0002] As the core component of the magnetic circuit, the lamination material and structure of the motor stator core directly determine the power density, efficiency and temperature rise characteristics of the motor. However, there are still critical problems in the application of cold-rolled silicon steel sheets widely used at present (such as 50W350, 35h210, etc.). First, the low stacking factor leads to insufficient utilization of the magnetic circuit. The stacking factor (SF) is the ratio of the effective magnetic conduction area to the theoretical geometric area. In the traditional process, an insulating coating of 2 - 5 mm (such as phosphate or CrO3 coating) needs to be coated on the surface of the silicon steel sheet, and there is a gap of 0.5 - 1.5 mm between the sheets during lamination, resulting in a stacking factor of only 92 - 95%. Taking a stator with an outer diameter of 200 mm as an example, the actual effective magnetic conduction area is reduced by about 8%, which is equivalent to losing 5 - 7% of the torque output capacity. Although the stacking factor can be appropriately increased by using an ultra-thin coating, this also leads to a decrease in the inter-sheet insulation resistance and a risk of local short circuit. Secondly, due to the saturation magnetic induction intensity (B s ) of conventional silicon steel sheets being only 1.8 - 2.0 T, when the designed magnetic density of the motor approaches 1.6 T, the iron core has entered the non-linear saturation region, resulting in a sharp rise in the excitation current. And the eddy current loss is relatively high under high-frequency working conditions. In view of the above problems, the existing technical improvement solutions mainly focus on material substitution, structure optimization and composite magnetic circuits, etc., but there are also disadvantages such as excessive brittleness of the material, high process complexity and a decrease in magnetic permeability.

[0003] Therefore, it is necessary to design a novel stator core from the perspective of structural-performance collaborative optimization and low cost to further improve the performance of the motor. Summary of the Invention

[0004] The main object of the present invention is to design a novel composite lamination structure for a motor stator core, by introducing FeSi-based nanocrystalline alloy into the traditional lamination structure, so as to increase the stacking factor and the saturation magnetic induction intensity, thereby improving the overall performance of the motor.

[0005] To achieve the above object, the present invention adopts the following design scheme: A novel composite lamination structure for a motor stator core, which is an axial gradient composite structure, with the middle region of the lamination being FeSi-based nanocrystalline alloy and the two end regions being traditional silicon steel laminations.

[0006] The thickness of the FeSi-based nanocrystalline alloy layer does not exceed 80% of the total thickness of the stator.

[0007] The single - end thickness of the two end regions is 0.1 - 0.25 of the total thickness, and the thickness of the middle region is 0.5 - 0.8 of the total thickness.

[0008] The joint surface of the FeSi - based nanocrystalline alloy and the traditional silicon steel laminations is designed as a stepped meshing structure.

[0009] In the stepped meshing structure, complementary groove teeth are correspondingly designed on the end face of the nanocrystalline segment; equally - spaced rectangular teeth are machined on the end face of the silicon steel segment.

[0010] The composite laminations adopt a multi - layer insulation system, including inter - layer insulation of silicon steel sheets, with a high - temperature - resistant polyimide coating on the surface of the silicon steel sheets; inter - segment insulation, with mica sheets arranged at the joint surface between the nanocrystalline and the silicon steel; surface insulation, with the whole impregnated with epoxy resin containing Al2O3 nanoparticles.

[0011] A novel composite lamination structure for the stator core of an electric machine according to the present invention is improved in the following three aspects: 1. Axial segmented topology optimization: The total thickness L (unit: mm) of the stator laminations is divided into a middle segment L1 (FeSi - based nanocrystalline) and two end segments L2 (silicon steel laminations): a. Middle segment: The thickness L1 = 0.5L - 0.8L; all are made of solid nanocrystalline blocks; b. End segments: The single - end thickness L2 = 0.1L - 0.25L, which are laminated by cold - rolled silicon steel sheets; c. Proportion constraint: The total proportion of the middle segment is preferably 0.2L - 0.4L (for balance between improvement and cost). s

[0012] 2. Joint surface geometric design: To avoid magnetic flux mutation, the joint surface between the silicon steel and the nanocrystalline is designed as a stepped meshing structure: a. Nanocrystalline segment end face: Complementary groove teeth are correspondingly designed (tooth width W2 = 2.9 mm, groove width S2 = 3.1 mm, tooth height H2 = 0.5 mm); b. Silicon steel segment end face: Equally - spaced rectangular teeth are machined (tooth width W1 = 3.0 mm, groove width S1 = 2.8 mm, tooth height H1 = 0.5 mm); c. Clearance fit: The radial unilateral clearance δ = 0.05 mm.

[0013] 3. Multi - layer insulation system: a. Inter - layer insulation of silicon steel sheets: A 2 - μm high - temperature - resistant polyimide coating is applied on the surface of the silicon steel sheets; b. Inter - segment insulation: A 0.1 - mm mica sheet is arranged at the joint surface between the nanocrystalline and the silicon steel; c. Surface insulation: The whole is impregnated with epoxy resin containing 30% Al2O3 nanoparticles.

[0014] The present invention breaks through the traditional homogeneous design idea of the full lamination of the stator, proposes an axial gradient composite structure, replaces the middle region of the lamination with a FeSi-based nanocrystalline alloy, and retains the traditional silicon steel lamination in the two end regions. On the one hand, this partial replacement effectively alleviates the problem of low stacking factor caused by the full lamination, and at the same time avoids the high cost problem caused by replacing all materials. On the other hand, the high B s characteristics of the FeSi-based nanocrystalline alloy are used to improve the magnetic loading capacity of the end part, thereby increasing the overall magnetic flux density, while retaining the low eddy current loss of the middle section of the silicon steel lamination, realizing the synergistic optimization of structure and performance. Specific embodiments

[0015] The above scheme will be further described below in conjunction with specific implementation examples. The preferred embodiments of the present invention are described in detail as follows: Embodiment 1

[0016] 1. Axial segmented topology optimization: The total thickness L (unit: mm) of the stator lamination is divided into a middle section L1 (FeSi-based nanocrystalline) and two end sections L2 (silicon steel lamination): a. Middle section: The thickness L1 = 0.8L; all use solid nanocrystalline alloy; b. End sections: The single-end thickness L2 = 0.1L, which is laminated by cold-rolled silicon steel sheets; c. Matching gap: The radial unilateral gap δ = 0.05 mm.

[0017] 2. Joint surface geometry design: To avoid sudden changes in magnetic flux, the joint surface between the silicon steel and the nanocrystalline is designed as a stepped meshing structure: a. End face of the silicon steel section: Process equally spaced rectangular teeth (tooth width W1 = 3.0 mm, slot width S1 = 2.8 mm, tooth height H1 = 0.5 mm); b. End face of the nanocrystalline section: Design complementary slot teeth correspondingly (tooth width W2 = 2.9 mm, slot width S2 = 3.1 mm, tooth height H2 = 0.5 mm); c. Matching gap: The radial unilateral gap δ = 0.05 mm.

[0018] 3. Multilayer insulation system: a. Interlayer insulation of silicon steel sheets: Coat the surface of the silicon steel sheets with a 2 μm high-temperature polyimide coating; b. Intersection insulation: Set a 0.1 mm mica sheet at the joint surface between the nanocrystalline and the silicon steel; c. Surface insulation: The whole is impregnated with an epoxy resin containing 30% Al2O3 nanoparticles. Embodiment 2

[0019] 1. Axial segmented topology optimization: The total thickness L (unit: mm) of the stator lamination is divided into two end segments L2 (silicon steel laminations) and an intermediate segment L1 (FeSi-based nanocrystals): a. End segments: The single-end thickness L2 = 0.15L; laminated from cold-rolled silicon steel sheets; b. Intermediate segment: The thickness L1 = 0.7L, all made of solid nanocrystal blocks; 2. Joint surface geometric design: To avoid sudden changes in magnetic flux, the joint surface between silicon steel and nanocrystals is designed as a stepped meshing structure: a. End face of the silicon steel segment: Equally spaced rectangular teeth are machined (tooth width W1 = 3.0 mm, slot width S1 = 2.8 mm, tooth height H1 = 0.5 mm); b. End face of the nanocrystal segment: Complementary slot teeth are designed correspondingly (tooth width W2 = 2.9 mm, slot width S2 = 3.1 mm, tooth height H2 = 0.5 mm); c. Clearance for fitting: The radial unilateral clearance δ = 0.05 mm.

[0020] 3. Multilayer insulation system: a. Interlayer insulation of silicon steel sheets: The surface of the silicon steel sheets is coated with a 2-μm high-temperature polyimide coating; b. Inter-segment insulation: A 0.1-mm mica sheet is set at the joint surface between nanocrystals and silicon steel; c. Surface insulation: The whole is impregnated with an epoxy resin containing 30% Al2O3 nanoparticles. Example 3

[0021] 1. Axial segmented topology optimization: The total thickness L (unit: mm) of the stator lamination is divided into two end segments L2 (steel laminations) and an intermediate segment L1 (FeSi-based nanocrystalline silicon): a. End segments: The single-end thickness L2 = 0.2L; laminated from cold-rolled silicon steel sheets; b. Intermediate segment: The thickness L1 = 0.6L, all made of solid nanocrystal blocks; 2. Joint surface geometric design: To avoid sudden changes in magnetic flux, the joint surface between silicon steel and nanocrystals is designed as a stepped meshing structure: a. End face of the silicon steel segment: Equally spaced rectangular teeth are machined (tooth width W1 = 3.0 mm, slot width S1 = 2.8 mm, tooth height H1 = 0.5 mm); b. End face of the nanocrystal segment: Complementary slot teeth are designed correspondingly (tooth width W2 = 2.9 mm, slot width S2 = 3.1 mm, tooth height H2 = 0.5 mm); c. Clearance for fitting: The radial unilateral clearance δ = 0.05 mm.

[0022] 3. Multilayer insulation system: a. Interlayer insulation of silicon steel sheets: The surface of the silicon steel sheets is coated with a 2-μm high-temperature resistant polyimide coating; b. Inter-stage insulation: A 0.1-mm mica sheet is provided at the joint surface between the nanocrystalline and the silicon steel; c. Surface insulation: The whole is impregnated with an epoxy resin containing 30% Al2O3 nanoparticles.

[0023] The present invention conducts performance tests on the samples in the above embodiments, and the test results are shown in Table 1.

[0024] Table 1. Performance tests of the samples in the embodiments Sample Lamination factor / % <![CDATA[B s / T]]> Example 1 97.2 1.97 Example 2 97.5 2.01 Example 3 98.1 2.06 The embodiments described in the present invention are only descriptions of the preferred embodiments of the present invention, and do not limit the concept and scope of the present invention. Without departing from the design concept of the present invention, various modifications and improvements made by those skilled in the art to the technical solutions of the present invention shall fall within the protection scope of the present invention. The technical content claimed by the present invention has been fully recorded in the claims.

Claims

1. A new composite lamination structure for motor stator core, characterized in that It is an axial gradient composite structure. The middle area of ​​the laminate is FeSi-based nanocrystalline alloy, and the two end areas are traditional silicon steel laminates.

2. According to claim 1, a novel composite laminate structure for a motor stator core is characterized in that the thickness of the FeSi-based nanocrystalline alloy layer does not exceed 80% of the total thickness of the stator.

3. According to claim 2, a new composite laminate structure for a motor stator core is characterized in that the single-end thickness of the two end regions is 0.1 to 0.25 of the total thickness, and the thickness of the middle region is 0.5 to 0.8 of the total thickness.

4. A novel composite lamination structure for a motor stator core according to claim 1, characterized in that the bonding surface between the FeSi-based nanocrystalline alloy and the traditional silicon steel lamination is designed as a stepped meshing structure.

5. A novel composite lamination structure for a motor stator core according to claim 4, characterized in that, in the stepped meshing structure, complementary slot teeth are designed correspondingly on the end faces of the nanocrystalline segments; and equidistant rectangular teeth are processed on the end faces of the silicon steel segments.

6. According to claim 1, a new composite lamination structure for a motor stator core is characterized in that the composite lamination adopts a multi-layer insulation system, including interlayer insulation of silicon steel sheets, the surface of the silicon steel sheets is coated with a high-temperature resistant polyimide coating; inter-segment insulation, mica sheets are arranged on the bonding surface of the nanocrystal and silicon steel; surface insulation, the whole is impregnated with an epoxy resin containing Al2O3 nanoparticles.