Anti-demagnetization less-rare-earth permanent magnet synchronous motor rotor structure

Abstract

The invention provides an anti-demagnetization less-rare earth permanent magnet synchronous motor rotor structure, which comprises a rotor body, a plurality of magnetic steel groove units and a plurality of magnetic steel units in one-to-one correspondence with the magnetic steel groove units, and is characterized in that each magnetic steel groove unit comprises a plurality of magnetic steel groove modules distributed layer by layer along the radial direction of the rotor body; the magnetic steel groove module comprises a first magnetic steel groove and two second magnetic steel grooves which are symmetrically distributed on two sides of the first magnetic steel groove; the magnetic steel unit comprises a plurality of magnetic steel modules in one-to-one correspondence with the magnetic steel groove modules. Each magnetic steel module comprises ferrite fixedly arranged in the first magnetic steel groove and two rare earth permanent magnets fixedly arranged in the two second magnetic steel grooves respectively. According to the scheme, the consumption of the rare earth permanent magnets can be reduced, and the motor cost is reduced; the two rare earth permanent magnets are arranged on the two sides of the ferrite respectively, so that compared with a ferrite permanent magnet motor, the demagnetization influence of an armature winding in the motor on the ferrite can be reduced, and the overload capacity of the motor is improved.

Description

Technical Field

[0001] The invention relates to the technical field of motors, and in particular to a demagnetization-resistant rare-earth permanent magnet synchronous motor rotor structure. Background Art

[0002] Electric vehicles have the characteristics of energy saving and environmental protection, and have been rapidly developed. In order to achieve high power density and high efficiency of the existing electric vehicle drive motors, more and more motors use high-performance rare earth permanent magnet motors.

[0003] Rare earth permanent magnet motors can achieve high efficiency and high power density, mainly relying on high-performance rare earth permanent magnets. Currently, the most widely used is neodymium iron boron rare earth permanent magnets. However, rare earth is a non-renewable resource, which is relatively expensive, and the price of rare earth also fluctuates greatly, resulting in high production costs for electric vehicle drive motors, which is very unfavorable for promoting the comprehensive development of electric vehicles. Furthermore, ferrite permanent magnet assisted synchronous reluctance motors are also used in electric vehicles in the prior art, but this type of motor has problems such as easy demagnetization and low efficiency. Summary of the invention

[0004] Based on the above problems existing in the prior art, the present invention aims to solve the technical problems in the prior art that rare earth permanent magnet motors have high production costs, and ferrite permanent magnet assisted synchronous reluctance motors are easy to demagnetize and have low efficiency.

[0005] The present invention provides a demagnetization-resistant rare earth permanent magnet synchronous motor rotor structure, which comprises:

[0006] Rotor body;

[0007] A plurality of magnetic steel slot units are evenly distributed along the circumferential direction of the rotor body, wherein the magnetic steel slot unit comprises a plurality of magnetic steel slot modules distributed layer by layer along the radial direction of the rotor body, wherein the magnetic steel slot module comprises a first magnetic steel slot and two second magnetic steel slots symmetrically distributed on both sides of the first magnetic steel slot;

[0008] A plurality of magnetic steel units corresponding one-to-one to the magnetic steel slot units, the magnetic steel unit comprising a plurality of magnetic steel modules corresponding one-to-one to the magnetic steel slot modules, the magnetic steel module comprising a ferrite fixedly arranged in the first magnetic steel slot and two rare earth permanent magnets respectively fixedly arranged in the two second magnetic steel slots.

[0009] According to an embodiment of the present invention, the magnetic steel slot modules in the magnetic steel slot unit are distributed in two layers, inner and outer, along the radial direction of the rotor body.

[0010] According to an embodiment of the present invention, the demagnetization-resistant rare earth permanent magnet synchronous motor rotor structure further includes a magnetic isolation bridge, and the magnetic isolation bridge is formed between the second magnetic steel slot and the outer circumference of the rotor body.

[0011] According to an embodiment of the present invention, the demagnetization-resistant rare earth permanent magnet synchronous motor rotor structure further includes reinforcing ribs, and the reinforcing ribs are formed between the second magnetic steel slots and the magnetic isolation bridges.

[0012] According to an embodiment of the present invention, the ratio of the width L1 of the ferrite located in the outer layer to the width L2 of the rare earth permanent magnet is 1-2:1, and the ratio of the thickness d1 of the ferrite to the thickness d2 of the rare earth permanent magnet is 1-2:1;

[0013] The ratio of the width L3 of the ferrite located in the inner layer to the width L4 of the rare earth permanent magnet is 1-2:1, and the ratio of the thickness d3 of the ferrite to the thickness d4 of the rare earth permanent magnet is 1-2:1.

[0014] According to an embodiment of the present invention, the demagnetization-resistant rare earth permanent magnet synchronous motor rotor structure further includes a magnetic bridge, and the magnetic bridge is formed between the first magnetic steel slot and the second magnetic steel slot.

[0015] According to an embodiment of the present invention, the first magnetic steel slot and the two second magnetic steel slots symmetrically distributed on both sides thereof form a "U"-shaped magnetic steel slot module.

[0016] According to an embodiment of the present invention, the rare earth permanent magnet is in the shape of a cuboid.

[0017] According to an embodiment of the present invention, the magnetization directions of the ferrite and the rare earth permanent magnet are both along the radial direction of the rotor body.

[0018] According to an embodiment of the present invention, the first magnetic steel groove and the second magnetic steel groove are respectively filled with resin.

[0019] The present invention provides a demagnetization-resistant rare earth permanent magnet synchronous motor rotor structure, which has the following beneficial effects:

[0020] (1) By arranging the ferrite in the first magnetic steel slot and the rare earth permanent magnet in the second magnetic steel slot, the amount of the rare earth permanent magnet can be reduced compared with the rare earth permanent magnet motor in the prior art, thereby reducing the cost of the motor;

[0021] (2) Since the stator of the motor will generate a demagnetizing magnetic field, and since the magnetic properties of the rare earth permanent magnet are better than those of the ferrite, the magnetic energy product, residual magnetic density and coercive force and other properties are higher, by arranging the two rare earth permanent magnets on both sides of the ferrite respectively, compared with the ferrite permanent magnet motor, the demagnetizing effect of the armature winding in the motor on the ferrite can be reduced, thereby improving the overload capacity of the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 It is a structural schematic diagram of a demagnetization-resistant rare earth permanent magnet synchronous motor rotor structure before a magnetic steel unit is installed, provided in an embodiment of the present invention;

[0024] Figure 2 It is a structural schematic diagram of a demagnetization-resistant rare earth permanent magnet synchronous motor rotor structure provided by an embodiment of the present invention;

[0025] Figure 3 is a schematic structural diagram of a magnetic steel unit in an embodiment of the present invention;

[0026] Figure 4 Schematic diagram of magnetization direction of ferrite and rare earth permanent magnet in an embodiment of the present invention;

[0027] Figure numerals: 1-rotor body; 2-magnetic steel slot unit; 20-magnetic steel slot module; 201-first magnetic steel slot; 202-second magnetic steel slot; 3-magnetic steel unit; 30-magnetic steel module; 301-ferrite; 302-rare earth permanent magnet; 4-magnetic isolation bridge; 5-reinforcement rib; 6-magnetic conductive bridge. DETAILED DESCRIPTION

[0028] The following descriptions of the embodiments refer to the attached drawings to illustrate specific embodiments in which the present invention can be implemented.

[0029] The present invention provides a demagnetization-resistant rare earth permanent magnet synchronous motor rotor structure, the structure of which is as follows: Figure 1 and Figure 2 As shown, it includes a rotor body 1, a plurality of magnetic steel slot units 2 and a plurality of magnetic steel units 3 corresponding to the magnetic steel slot units 2, wherein the plurality of magnetic steel slot units 2 are evenly distributed along the circumferential direction of the rotor body 1, the magnetic steel slot unit 2 includes a plurality of magnetic steel slot modules 20 distributed layer by layer along the radial direction of the rotor body 1, the magnetic steel slot module 20 includes a first magnetic steel slot 201 and two second magnetic steel slots 202 symmetrically distributed on both sides of the first magnetic steel slot 201; the magnetic steel unit 3 includes a plurality of magnetic steel modules 30 corresponding to the magnetic steel slot module 20, the magnetic steel module 30 includes a ferrite 301 fixedly arranged in the first magnetic steel slot 201 and two rare earth permanent magnets 302 respectively fixedly arranged in the two second magnetic steel slots 202; specifically, the rare earth permanent magnet 302 is in the shape of a cuboid.

[0030] Please continue to refer to Figure 2 Specifically, in this embodiment, the number of the magnetic steel slot units 2 is set to 6, and the 6 magnetic steel slot units 2 are evenly arranged along the circumferential direction of the rotor body 1; the magnetic steel slot modules 20 in the magnetic steel slot units 2 are distributed in the radial direction of the rotor body 1 with inner and outer layers; Figure 4 Schematic diagram of the magnetization direction of the ferrite 301 and the rare earth permanent magnet 302 in the embodiment of the present invention is shown. The magnetization directions of the ferrite 301 and the rare earth permanent magnet 302 are both along the radial direction of the rotor body 1.

[0031] like Figure 3 The figure is a schematic diagram of the structure of the magnetic steel unit 3 in the embodiment of the present invention. Furthermore, since the magnetic energy product, residual magnetic density and coercive force of the ferrite 301 are relatively poor, in order to make the anti-demagnetization ability of the ferrite 301 and the rare earth permanent magnet 302 in this scheme consistent, the ratio of the width L1 of the ferrite 301 located in the outer layer to the width L2 of the rare earth permanent magnet 302 is set to 1-2:1, and the ratio of the thickness d1 of the ferrite 301 to the thickness d2 of the rare earth permanent magnet 302 is set to 1-2:1; the ratio of the width L3 of the ferrite 301 located in the inner layer to the width L4 of the rare earth permanent magnet 302 is set to 1-2:1, and the ratio of the thickness d3 of the ferrite 301 to the thickness d4 of the rare earth permanent magnet 302 is set to 1-2:1.

[0032] It should be noted that setting the magnetic steel slot unit 2 to include two layers of the magnetic steel slot modules 20 is only a preferred embodiment of the present solution. In other embodiments, the magnetic steel slot unit 2 can also be set to include more layers (for example, four layers) of the magnetic steel slot modules 20.

[0033] Preferably, the first magnetic steel slot 201 and the two second magnetic steel slots 202 symmetrically distributed on both sides thereof form a "U"-shaped magnetic steel slot module 20.

[0034] It is not difficult to understand that the "U"-shaped magnetic steel slot module 20 can extend the length of the magnetic steel placed in the unit volume of the rotor, thereby generating a larger permanent magnet torque, improving the q-axis inductance of the motor, and increasing the motor efficiency.

[0035] Furthermore, in order to fix the ferrite 301 and the rare earth permanent magnet 302 in the first magnetic steel slot 201 and the second magnetic steel slot 202 respectively, the first magnetic steel slot 201 and the second magnetic steel slot 202 are also filled with resin respectively.

[0036] In this embodiment, the demagnetization-resistant rare earth permanent magnet synchronous motor rotor structure also includes a magnetic isolation bridge 4. The magnetic isolation bridge 4 is formed between the second magnetic steel slot 202 and the outer circumference of the rotor body 1, which can effectively reduce magnetic leakage.

[0037] It should be noted that, affected by the outer diameter size of the rotor body 1 (the outer diameter size of the rotor body 1 is relatively small), in this embodiment, the magnetic isolation bridge 4 is formed only between the second magnetic steel slot 202 located in the inner layer and the outer circumference of the rotor body 1, and the magnetic isolation bridge 4 is not arranged between the second magnetic steel slot 202 in the outer layer and the outer circumference of the rotor body 1. In actual applications, in order to better reduce the magnetic leakage phenomenon, the magnetic isolation bridge 4 should be formed between the second magnetic steel slot 202 in each layer and the outer circumference of the rotor body 1.

[0038] Furthermore, the anti-demagnetization rare earth permanent magnet synchronous motor rotor structure further includes a reinforcing rib 5, which is formed between the second magnetic steel slot 202 and the magnetic isolation bridge 4 to improve strength. Preferably, the reinforcing rib 5 is integrally formed on the rotor body 1.

[0039] Furthermore, the demagnetization-resistant rare earth permanent magnet synchronous motor rotor structure further includes a magnetic bridge 6 , and the magnetic bridge 6 is formed between the first magnetic steel slot 201 and the second magnetic steel slot 202 for magnetic lines of force to pass through.

[0040] Compared with the prior art, the present invention provides a demagnetization-resistant rare earth permanent magnet synchronous motor rotor structure. By arranging the ferrite 301 in the first magnetic steel slot 201 and the rare earth permanent magnet 302 in the second magnetic steel slot 202, the use of the rare earth permanent magnet 302 can be reduced compared with the rare earth permanent magnet motor in the prior art, thereby reducing the cost of the motor; in addition, since the stator of the motor will generate a demagnetizing magnetic field, and since the magnetic properties of the rare earth permanent magnet 302 are better than those of the ferrite 301, the magnetic energy product, residual magnetic density and coercive force and other properties are higher, by arranging the two rare earth permanent magnets 302 on both sides of the ferrite 301 respectively, the demagnetization effect of the armature winding in the motor on the ferrite can be reduced compared with the ferrite permanent magnet motor, thereby improving the overload capacity of the motor.

[0041] It should be noted that although the present invention is disclosed as above by specific embodiments, the above embodiments are not intended to limit the present invention. Ordinary technicians in this field can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be based on the scope defined in the claims.

Claims

1. A demagnetization-resistant rare earth permanent magnet synchronous motor rotor structure, characterized in that: include: A rotor body (1); A plurality of magnetic steel slot units (2) are evenly distributed along the circumferential direction of the rotor body (1), the magnetic steel slot unit (2) comprising a plurality of magnetic steel slot modules (20) distributed layer by layer along the radial direction of the rotor body (1), the magnetic steel slot module (20) comprising a first magnetic steel slot (201) and two second magnetic steel slots (202) symmetrically distributed on both sides of the first magnetic steel slot (201); A plurality of magnetic steel units (3) corresponding one-to-one to the magnetic steel slot units (2), the magnetic steel units (3) comprising a plurality of magnetic steel modules (30) corresponding one-to-one to the magnetic steel slot modules (20), the magnetic steel modules (30) comprising a ferrite (301) fixedly arranged in the first magnetic steel slot (201) and two rare earth permanent magnets (302) respectively fixedly arranged in the two second magnetic steel slots (202).

2. The anti-demagnetization rare earth permanent magnet synchronous motor rotor structure according to claim 1, characterized in that: The magnetic steel slot modules (20) in the magnetic steel slot unit (2) are distributed in two layers, inner and outer, along the radial direction of the rotor body (1).

3. The anti-demagnetization rare earth permanent magnet synchronous motor rotor structure according to claim 2, characterized in that: It also includes a magnetic isolation bridge (4), wherein the magnetic isolation bridge (4) is formed between the second magnetic steel slot (202) and the outer circumference of the rotor body (1).

4. The anti-demagnetization rare earth permanent magnet synchronous motor rotor structure according to claim 3 is characterized in that: It also includes a reinforcing rib (5), wherein the reinforcing rib (5) is formed between the second magnetic steel slot (202) and the magnetic isolation bridge (4).

5. The anti-demagnetization rare earth permanent magnet synchronous motor rotor structure according to claim 2, characterized in that: The ratio of the width L1 of the ferrite (301) located in the outer layer to the width L2 of the rare earth permanent magnet (302) is 1 to 2:1, and the ratio of the thickness d1 of the ferrite (301) to the thickness d2 of the rare earth permanent magnet (302) is 1 to 2:1; The ratio of the width L3 of the ferrite (301) located in the inner layer to the width L4 of the rare earth permanent magnet (302) is 1-2:1, and the ratio of the thickness d3 of the ferrite (301) to the thickness d4 of the rare earth permanent magnet (302) is 1-2:

1.

6. A demagnetization-resistant rare earth permanent magnet synchronous motor rotor structure according to any one of claims 1 to 5, characterized in that: It also includes a magnetic conductive bridge (6), and the magnetic conductive bridge (6) is formed between the first magnetic steel slot (201) and the second magnetic steel slot (202).

7. A demagnetization-resistant rare earth permanent magnet synchronous motor rotor structure according to any one of claims 1 to 5, characterized in that: The first magnetic steel slot (201) and the two second magnetic steel slots (202) symmetrically distributed on both sides thereof form a "U"-shaped magnetic steel slot module (20).

8. The anti-demagnetization rare earth permanent magnet synchronous motor rotor structure according to any one of claims 1 to 5, characterized in that: The rare earth permanent magnet (302) is in the shape of a rectangular parallelepiped.

9. The anti-demagnetization rare earth permanent magnet synchronous motor rotor structure according to any one of claims 1 to 5, characterized in that: The magnetization directions of the ferrite (301) and the rare earth permanent magnet (302) are both along the radial direction of the rotor body (1).

10. The anti-demagnetization rare earth permanent magnet synchronous motor rotor structure according to any one of claims 1 to 5, characterized in that: The first magnetic steel groove (201) and the second magnetic steel groove (202) are also filled with resin respectively.

Images