A rotor slotting device and a bilateral permanent magnet motor thereof

Abstract

The present invention provides a rotor slotting device and a bilateral permanent magnet motor thereof, which consists of a stator and a rotor, and is an outer stator and inner rotor structure, and an air gap exists between the rotor and the stator. There are permanent magnets and armature windings on the stator, the stator is slotted, and the stator teeth are split tooth structures to form modulation poles, and the teeth are embedded with first permanent magnets whose magnetization directions are all radially outward or inward. The rotor is a salient pole structure, and is embedded with a second permanent magnet whose magnetization directions are all radially outward or inward. There are slots with a combination structure of straight lines and arcs or multiple broken lines on both sides of the second permanent magnet, and the bending directions of the slots all point to the magnetic pole axis. The rotor is fixed on the rotating shaft as the only mechanical port of the motor. It can significantly reduce the rotor iron loss and alleviate the problem of excessive iron loss during the operation of the permanent magnet motor.

Description

Technical Field

[0001] The present invention relates to the field of new energy vehicle motors and transmission technology, and in particular to a rotor slotting device and a bilateral permanent magnet motor thereof. Background Art

[0002] In the field of modern motor design, permanent magnet motor is a typical representative of magnetic field modulation motor. With its advantages of simple structure, high torque density and power density, permanent magnet motor has attracted widespread attention, especially in the rapidly developing field of electric vehicle motor drive. Traditional motors usually adopt a single-sided excitation structure, but this design is limited by magnetic load in improving torque density, which affects the further improvement of motor performance.

[0003] In order to solve this bottleneck, some scholars have proposed an innovative solution of bilateral excitation. Based on the principle of bidirectional magnetic field modulation effect, they have designed a dual permanent magnet motor structure with permanent magnets placed on both the stator and the rotor. This design has effectively improved the torque density of the motor to a certain extent. However, the introduction of the bidirectional magnetic field modulation effect also leads to an increase in the harmonics of the motor magnetic field, which in turn causes an increase in core loss and reduces the overall efficiency of the motor.

[0004] At present, most of the double-sided permanent magnet motors with rotor slot structures are rectangular slots, but their effect in reducing iron loss is very limited, and they also have a certain negative impact on the torque density of the motor. Therefore, in future designs, it is urgent to explore more effective structural solutions and magnetic field modulation technologies to further optimize motor performance and meet the growing market demand.

[0005] In view of this, this application is filed. Summary of the invention

[0006] The present invention provides a rotor slotting device and a bilateral permanent magnet motor thereof, which can at least partially improve the above-mentioned problem.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] A rotor slotting device comprises: a stator assembly arranged on a housing of a double-sided permanent magnet motor, and a rotor assembly fixed on a rotating shaft of the double-sided permanent magnet motor, wherein a gap is formed between the stator assembly and the rotor assembly:

[0009] The rotor assembly comprises a rotor core, a plurality of second permanent magnets and a plurality of rotor slots, wherein the rotor core comprises a first annular support and a plurality of first protrusions, wherein each of the first protrusions is evenly spaced and distributed outside the first annular support, and a first slot body is formed between adjacent first protrusions, wherein the second permanent magnet is disposed in the first slot body, and the first protrusion comprises an arc portion connected to the first annular support and a vertical portion connected to the arc portion, wherein both sides of the arc portion shrink in a direction away from the first annular support and are flush with the vertical portion;

[0010] A second protrusion is formed between adjacent first protrusions, wherein the height of the second protrusion is flush with the junction of the arc portion and the vertical portion, and a rotor slot is formed between the second protrusion and the arc portion of the first protrusion, and the curvature of the second protrusion is the same as that of the arc portion.

[0011] The present invention also provides a bilateral permanent magnet motor, which includes: a bilateral permanent magnet motor body, a shell configured on the bilateral permanent magnet motor body, and a rotor slotting device as described above, wherein the stator assembly is configured on the shell and the rotor assembly is fixed on the rotating shaft of the bilateral permanent magnet motor body.

[0012] In summary, the rotor slotting device consists of two parts, a stator and a rotor, with an outer stator and an inner rotor structure, and there is an air gap between the rotor and the stator. There are permanent magnets and armature windings on the stator, the stator is slotted, and the stator teeth are split tooth structures to form modulation poles, and the teeth are embedded with first permanent magnets whose magnetization directions are all radially outward or inward. The rotor has a salient pole structure and is embedded with a second permanent magnet whose magnetization direction is all radially outward or inward. There are slots with a combination structure of straight lines and arcs or multiple broken lines on both sides of the second permanent magnet, and the bending directions of the slots all point to the axis of the magnetic pole. The rotor is fixed on the rotating shaft as the only mechanical port of the motor. It can significantly reduce the rotor iron loss and alleviate the problem of excessive iron loss during the operation of the permanent magnet motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a schematic structural diagram of a rotor slotting device provided in an embodiment of the present invention;

[0014] Figure 2 is a schematic diagram of the rotor core structure of a rotor slotting device provided in an embodiment of the present invention;

[0015] Figure 3 is a schematic diagram of a rotor slotting structure of a rotor slotting device provided in an embodiment of the present invention;

[0016] Figure 4 is a schematic diagram of the stator core structure of the rotor slotting device provided in an embodiment of the present invention;

[0017] Figure 5 It is a torque comparison diagram of a double-sided permanent magnet motor with a rotor slot structure, a rotor rectangular slot structure, and a motor without a rotor slot structure provided by an embodiment of the present invention;

[0018] Figure 6 It is a comparison chart of iron losses of double-sided permanent magnet motors with a rotor slot structure, a rotor rectangular slot structure, and no rotor slot structure provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0020] refer to Figure 1 , Figure 2 , Figure 3 As shown, the first embodiment of the present invention discloses a rotor slotting device, which comprises: a stator assembly configured on a housing of a double-sided permanent magnet motor, and a rotor assembly fixed on a rotating shaft of the double-sided permanent magnet motor, wherein a gap is formed between the stator assembly and the rotor assembly;

[0021] The rotor assembly includes a rotor core 21, a plurality of second permanent magnets 22, and a plurality of rotor slots 23. The rotor core 21 is composed of a first annular support 211 and a plurality of first protrusions 212. Each of the first protrusions 212 is evenly spaced and distributed outside the first annular support 211. A first slot body 213 is formed between adjacent first protrusions 212. The second permanent magnets 22 are arranged in the first slot body 213. The first protrusion 212 includes an arc portion 214 connected to the first annular support 211, and a vertical portion 215 connected to the arc portion 214. The two sides of the arc portion 214 shrink in a direction away from the first annular support 211 and are flush with the vertical portion 215.

[0022] A second protrusion 216 is formed between adjacent first protrusions 212 , wherein the height of the second protrusion 216 is flush with the junction of the arc portion 214 and the vertical portion 215 , and a rotor slot 23 is formed between the second protrusion 216 and the arc portion 214 of the first protrusion 212 , and the curvature of the second protrusion 216 is the same as that of the arc portion 214 .

[0023] Preferably, the rotor slots 23 are configured to cut off the magnetic lines of force of other magnetic circuits except the main magnetic circuit, thereby suppressing harmonics and reducing iron losses.

[0024] In this embodiment, the rotor is fixed on the rotating shaft as the only mechanical port of the motor, including a rotor core, a second permanent magnet 22 and a rotor slot. A plurality of empty slots are evenly distributed on the rotor core 21, each of which is embedded with a second permanent magnet 22. The magnetization direction of the permanent magnet is radially outward. There are rotor slots on both sides of the second permanent magnet 22. The slot shape is composed of a straight line plus an arc line or a straight line plus multiple broken lines, and the bending direction of the arc line or the multiple broken lines is the central axis of the second permanent magnet 22.

[0025] Among them, there are rotor slot structures on both sides of the second permanent magnet 22 in the rotor, and its shape is composed of a straight line plus an arc or a straight line plus a multi-segment line, and the bending direction of the arc or the multi-segment line is the central axis of the second permanent magnet 22. It suppresses harmonics by setting a magnetic barrier on the rotor, thereby achieving the effect of reducing iron loss. The rotor core in the rotor presents a salient pole structure, and only the second permanent magnet 22 is embedded in the rotor core. There is no excitation winding on the rotor, so brushes and slip rings are not required.

[0026] See also Figure 4 Preferably, the stator assembly includes a stator core 11, wherein the stator core 11 includes a second annular bracket 111, a plurality of stator teeth 112 uniformly distributed on the inner side of the second annular bracket 111, stator tooth slots 113 are formed between adjacent stator teeth 112, and the stator teeth 112 are formed with mutually symmetrical first modulation teeth 114 and second modulation teeth 115 on the side away from the second annular bracket 111, and a second slot body 116 is formed between the first modulation tooth 114 and the second modulation tooth 115.

[0027] Preferably, the stator assembly further includes a plurality of armature windings 12 and a plurality of first permanent magnets 13 , wherein the stator tooth slots 113 are used to accommodate the armature windings 12 , and the second slots 116 are used to accommodate the first permanent magnets 13 .

[0028] In this embodiment, each stator tooth of the stator core is evenly split into two small teeth to form a magnetic field modulation pole; in simple terms, each stator tooth of the stator core is evenly split into two small teeth, namely a first modulation tooth 114 and a second modulation tooth 115, which are used to modulate the magnetic field generated on the armature winding. There is an empty slot in each stator split tooth, and a first permanent magnet 13 is embedded in the slot, and the magnetization direction of the permanent magnet is radial.

[0029] Preferably, the number of permanent magnet pole pairs on the rotor assembly is , the number of pole pairs of the armature winding on the stator assembly , and the number of modulated teeth on the stator assembly The relationship between them is: .

[0030] In this embodiment, the bilateral permanent magnet motor used is a magnetic field modulation motor, and its slot-pole matching relationship needs to meet the following requirements: ,in, is the number of pole pairs of the stator armature winding, is the number of modulated teeth generated by the stator split-tooth structure, is the number of permanent magnet pole pairs on the rotor, Figure 1 In , these parameters are equal to 5, 19, and 24 respectively.

[0031] Preferably, the first permanent magnet 13 and the second permanent magnet 22 have the same magnetizing direction, wherein the magnetizing direction is a direction away from the center of the rotor core 21 , or a direction close to the center of the rotor core 21 .

[0032] In this embodiment, all first permanent magnets 13 have the same polarity, and the magnetization direction is radially inward or outward at the same time, so as to enhance the magnetic field strength, and the armature winding is placed in the stator slot. All second permanent magnets 22 have the same polarity as the first permanent magnets 13, and the magnetization direction is radially inward or outward at the same time, and there are slots in the shape of a straight line plus an arc or a straight line plus multiple segments on both sides of the second permanent magnets 22, so as to suppress the harmonic components in the rotor core.

[0033] Specifically, in this embodiment, when the motor is running, three-phase alternating current is passed through the armature winding in the stator, and the generated magnetic field is modulated by the stator split teeth to generate a harmonic magnetic field that can interact with the rotor magnetic field, thereby driving the rotor to move. The rotor slots on both sides of the second permanent magnet 22 suppress the harmonics of the rotor yoke, thereby reducing iron losses.

[0034] See also Figure 5 , Figure 6 Compared with the traditional method of suppressing harmonics by opening rectangular slots in rotors, the iron loss suppression method of the rotor slotting device has a more obvious effect of reducing iron loss when the torque influence is almost the same. According to the simulation results, the motor with rectangular slots can only reduce the iron loss to 76.55% of the original while sacrificing 5.57% of the torque, while the present embodiment can reduce the iron loss to 68.76% of the original while sacrificing 5.55% of the torque. At the same time, the rotor slotting helps to reduce the weight of the rotor core and realize the lightweight of the rotor core.

[0035] In summary, the rotor slotting device can significantly reduce the rotor iron loss, thereby alleviating the problem of excessive iron loss during operation of the permanent magnet motor.

[0036] The second embodiment of the present invention provides a bilateral permanent magnet motor, which includes a bilateral permanent magnet motor body, a shell configured on the bilateral permanent magnet motor body, and a rotor slotting device as described above, wherein the stator assembly is configured on the shell and the rotor assembly is fixed on the rotating shaft of the bilateral permanent magnet motor body.

[0037] The above is a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A rotor slotting device, characterized in that: include: A stator assembly configured on a housing of a double-sided permanent magnet motor, and a rotor assembly fixed on a rotating shaft of the double-sided permanent magnet motor, wherein a gap is formed between the stator assembly and the rotor assembly; The rotor assembly comprises a rotor core, a plurality of second permanent magnets and a plurality of rotor slots, wherein the rotor core comprises a first annular support and a plurality of first protrusions, wherein each of the first protrusions is evenly spaced outside the first annular support, and a first slot body is formed between adjacent first protrusions, wherein the second permanent magnet is disposed in the first slot body, and the first protrusion comprises an arc portion connected to the first annular support and a vertical portion connected to the arc portion, wherein both sides of the arc portion shrink in a direction away from the first annular support and are flush with the vertical portion; A second protrusion is formed between adjacent first protrusions, wherein the height of the second protrusion is flush with the junction of the arc portion and the vertical portion, and a rotor slot is formed between the second protrusion and the arc portion of the first protrusion, and the curvature of the second protrusion is the same as that of the arc portion.

2. The rotor slotting device according to claim 1, characterized in that: The rotor slots are configured to cut off the magnetic lines of force of other magnetic circuits except the main magnetic circuit, thereby suppressing harmonics and reducing iron losses.

3. The rotor slotting device according to claim 1, characterized in that: The stator assembly includes a stator core, wherein the stator core includes a second annular bracket, a plurality of stator teeth evenly distributed on the inner side of the second annular bracket, stator tooth slots are formed between adjacent stator teeth, and the stator teeth are formed with mutually symmetrical first modulation teeth and second modulation teeth on the side away from the second annular bracket, and a second slot body is formed between the first modulation teeth and the second modulation teeth.

4. The rotor slotting device according to claim 3, characterized in that: The stator assembly further includes a plurality of armature windings and a plurality of first permanent magnets, wherein the stator tooth slots are used to place the armature windings, and the second slots are used to place the first permanent magnets.

5. The rotor slotting device according to claim 4, characterized in that: The number of permanent magnet pole pairs on the rotor assembly , the number of pole pairs of the armature winding on the stator assembly , and the number of modulation teeth on the stator assembly The relationship between them is: .

6. The rotor slotting device according to claim 5, characterized in that: The magnetization direction of the first permanent magnet and the second permanent magnet is the same, wherein the magnetization direction is a direction away from the center of the rotor core, or a direction close to the center of the rotor core.

7. A bilateral permanent magnet motor, characterized in that: It comprises a bilateral permanent magnet motor body, a shell configured on the bilateral permanent magnet motor body, and a rotor slotting device as described in any one of claims 1 to 6, wherein the stator assembly is configured on the shell and the rotor assembly is fixed on the rotating shaft of the bilateral permanent magnet motor body.

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