A kind of anti-demagnetization rotor topology structure of asymmetric permanent magnet motor

Abstract

An asymmetric permanent magnet motor anti-demagnetization rotor topology structure belongs to the field of new energy vehicle motors. The present invention is to solve the problem that the rotor of an asymmetric permanent magnet synchronous motor is prone to demagnetization under high temperature and strong magnetic field. The present invention includes a rotor core, and a V-shaped magnetic steel slot is provided under each pole of the rotor core. The permanent magnet in each V-shaped magnetic steel slot adopts an asymmetric magnetic steel structure. Long permanent magnets and short permanent magnets are respectively placed inside the two straight slots of the V-shaped magnetic steel slot. The magnetization directions of the two permanent magnets are perpendicular to the extension direction of the magnetic steel slot; the long permanent magnet is subjected to pole clipping. The present invention is used to perform anti-demagnetization treatment on the rotor of an asymmetric permanent magnet synchronous motor.

Description

Technical Field

[0001] The invention relates to an anti-demagnetization rotor topology structure of an asymmetric permanent magnet motor, belonging to the field of motors for new energy vehicles. Background Art

[0002] At present, the main types of motors used to drive electric vehicles are induction motors, switched reluctance motors and permanent magnet synchronous motors. Among them, permanent magnet synchronous motors use permanent magnet excitation, without the need for electrical excitation, which effectively reduces the copper loss caused by the current passing through the wire, and this type of motor does not require a commutator, the motor operation reliability is higher, and the permanent magnet synchronous motor also has unique advantages in output torque, power density, efficiency, etc. my country is rich in rare earth permanent magnet resources, and its reserves and output rank first in the world, and it is ahead of other countries by a large margin, and has an inherent advantage in the development of permanent magnet motors. Although built-in permanent magnet synchronous motors have many advantages, due to the characteristics of rare earth permanent magnet materials themselves, when this type of motor is used for electric vehicle drive motors, irreversible demagnetization is prone to occur under high ambient temperature, strong reverse magnetic field, strong vibration and other working conditions. When irreversible demagnetization occurs, the magnetic properties of the permanent magnet material will decrease, the air gap magnetic flux density will decrease, and the output torque of the motor is positively correlated with the size of the air gap magnetic flux density, so the output torque of the motor will decrease and the efficiency of the motor will decrease. In order to maintain the original working state, the stator winding current will increase. The increased stator winding current will lead to increased copper loss, and will also increase the temperature inside the motor, further increasing the irreversible demagnetization of the permanent magnet, forming a vicious circle. At the least, it will lead to reduced motor efficiency, increased power consumption, and reduced mileage of electric vehicles; in severe cases, it may even cause motor control failure due to sudden demagnetization, affecting driving safety. Therefore, in order to ensure that the built-in permanent magnet synchronous motor can operate efficiently and stably, it is of great significance to study the irreversible demagnetization phenomenon of permanent magnet materials, design the motor to resist demagnetization, and suppress the irreversible demagnetization of permanent magnets.

[0003] Traditional built-in permanent magnet synchronous motors are widely used in various fields because they can generate large reluctance torque and weak magnetic area. However, the built-in rotor structure also generates large cogging torque, which leads to increased torque pulsation, mechanical vibration and noise, and affects its operating performance. Therefore, the problem of how to reduce the torque pulsation of built-in permanent magnet synchronous motors has attracted the attention of scholars at home and abroad. The asymmetric V-type built-in permanent magnet synchronous motor is used in the structural improvement of built-in permanent magnet synchronous motors because it has lower torque pulsation and higher output torque than traditional built-in permanent magnet synchronous motors. However, due to the asymmetric magnetic circuit of the rotor with an asymmetric structure, the traditional anti-demagnetization design of the built-in permanent magnet synchronous motor has almost lost its applicability. Therefore, it is necessary to carry out anti-demagnetization design for this asymmetric rotor structure. Summary of the invention

[0004] Aiming at the problem that there is no applicable anti-demagnetization design for the existing asymmetric rotor structure, the present invention provides an anti-demagnetization rotor topology structure for an asymmetric permanent magnet motor.

[0005] The anti-demagnetization rotor topology structure for an asymmetric permanent magnet motor of the present invention includes a rotor core 1. Each pole of the rotor core 1 is provided with a V-shaped magnet slot. The permanent magnets in each V-shaped magnet slot adopt an asymmetric magnetic steel structure. A long permanent magnet 6 and a short permanent magnet 2 are respectively placed in the two straight slots of the V-shaped magnet slot. The magnetization directions of the two permanent magnets are both perpendicular to the extension direction of the magnet slot.

[0006] The long permanent magnet 6 is subjected to pole shaving treatment.

[0007] Preferably, the rotor core 1 is formed by coaxially laminating a plurality of punching sheets.

[0008] Preferably, the long permanent magnet 6 adopts trapezoidal single-side pole shaving, and the shaving position is on the side of the left permanent magnet close to the air gap.

[0009] Preferably, the area of the right triangle shaved by the trapezoidal single-side pole shaving is 1.9432 mm 2 , where the length of one right-angled side is 6.94 mm and the length of the other right-angled side is 0.56 mm.

[0010] Preferably, a heart-shaped anti-demagnetization hole 3 is provided on the d-axis under each pole. The heart-shaped anti-demagnetization hole 3 is arranged in the opening of the V-shaped magnet slot close to the air gap side, and the heart-shaped anti-demagnetization hole 3 penetrates through the entire rotor core 1 along the axial direction.

[0011] Preferably, the radial width M3 of the heart-shaped anti-demagnetization hole 3 is 5.9 mm, and the tangential length M4 is 15.6 mm.

[0012] Preferably, a circular anti-demagnetization hole 5 is provided on the q-axis under each pole. The circular anti-demagnetization hole 5 is arranged between two adjacent V-shaped magnet slots, and the circular anti-demagnetization hole 5 penetrates through the entire rotor core 1 along the axial direction.

[0013] Preferably, the radius R1 of the circular anti-demagnetization hole 5 is 5 mm, and the center of the circular anti-demagnetization hole 5 is 72 mm away from the center of the motor shaft.

[0014] Preferably, a magnetic barrier 7 above the long permanent magnet is arranged in the V-shaped magnet slot on the side of the long permanent magnet close to the air gap, and a magnetic barrier 4 above the short permanent magnet is arranged in the V-shaped magnet slot on the side of the short permanent magnet close to the air gap.

[0015] Preferably, a magnetic barrier 8 below the permanent magnet is arranged on each side of the two straight slots of the V-shaped magnet slot close to the center of the motor, and the two magnetic barriers 8 below the permanent magnet are not connected.

[0016] Beneficial effects of the invention: The invention provides an asymmetric permanent magnet synchronous motor rotor with an anti-demagnetization structure, and two anti-demagnetization holes are designed on the motor rotor laminations. Due to the particularity of the asymmetric motor, an asymmetric single-sided clipped anti-demagnetization magnet structure is designed at the magnetic steel. While keeping the original motor torque unchanged, the torque pulsation of the motor is reduced. Through these designs, the magnetic circuit and the direction of the magnetic lines of force are optimized, the anti-demagnetization performance and critical demagnetization temperature of the motor are greatly improved, and the maximum operating temperature that the motor can withstand is increased. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a three-dimensional structural schematic diagram of an asymmetric permanent magnet motor anti-demagnetization rotor topology structure according to the present invention;

[0018] Figure 2 It is a schematic diagram of the rotor topology structure under each pole;

[0019] Figure 3 It is a schematic diagram of the long permanent magnet pole-cutting structure;

[0020] Figure 4 This is a partial enlarged view of the circular anti-demagnetization hole of the rotor;

[0021] Figure 5 This is a partial enlarged view of the heart-shaped anti-demagnetization hole of the rotor.

[0022] In all the drawings, the elements or structures represented by the reference numerals are as follows:

[0023] 1- rotor core, 2- short permanent magnet, 3- heart-shaped anti-demagnetization hole

[0024] 4-Magnetic barrier above the short permanent magnet, 5-Circular anti-demagnetization hole

[0025] 6-long permanent magnet, 7-magnetic barrier above the long permanent magnet on the left

[0026] 8-Magnetic barrier below the permanent magnet, 9-Pole-cutting part of the permanent magnet

[0027] M1-permanent magnet length after pole clipping, M2-permanent magnet pole clipping length

[0028] R1-circular anti-demagnetization hole diameter,

[0029] M3- radial width of the heart-shaped anti-demagnetization hole, M4- tangential length of the heart-shaped anti-demagnetization hole. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0032] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but they are not intended to limit the present invention.

[0033] Specific implementation method 1: The following is combined Figures 1 to 5 The present embodiment is described. The present embodiment describes an asymmetric permanent magnet motor anti-demagnetization rotor topology structure, including a rotor core 1. A V-shaped magnetic steel slot is provided under each pole of the rotor core 1. The permanent magnet in each V-shaped magnetic steel slot adopts an asymmetric magnetic steel structure. A long permanent magnet 6 and a short permanent magnet 2 are respectively placed inside two straight slots of the V-shaped magnetic steel slot. The magnetization directions of the two permanent magnets are perpendicular to the extension direction of the magnetic steel slot.

[0034] The long permanent magnet 6 is subjected to a pole clipping process.

[0035] The rotor core 1 is formed by coaxially stacking a plurality of punching sheets.

[0036] The long permanent magnet 6 is trapezoidal with single-side pole cutting, and the cutting position is on the side of the left permanent magnet close to the air gap.

[0037] Specific example of 6-pole cutting of a long permanent magnet: The area of ​​the right triangle cut off by cutting one side of the trapezoid is 1.9432mm 2 , one of the right-angled sides is 6.94mm long and the other right-angled side is 0.56mm long.

[0038] A heart-shaped anti-demagnetization hole 3 is arranged on the d-axis under each pole. The heart-shaped anti-demagnetization hole 3 is arranged in the opening of the V-shaped magnetic steel slot close to the air gap side. The heart-shaped anti-demagnetization hole 3 axially penetrates the entire rotor core 1.

[0039] A specific example of setting the heart-shaped anti-demagnetization hole 3 is as follows: the radial width M3 of the heart-shaped anti-demagnetization hole 3 is 5.9 mm, and the tangential length M4 is 15.6 mm.

[0040] A circular anti-demagnetization hole 5 is arranged on the q-axis under each pole. The circular anti-demagnetization hole 5 is arranged between two adjacent V-shaped magnetic steel slots. The circular anti-demagnetization hole 5 runs through the entire rotor core 1 along the axial direction.

[0041] A specific example of setting a circular anti-demagnetization hole 5 is as follows: the radius R1 of the circular anti-demagnetization hole 5 is 5 mm, and the center of the circular anti-demagnetization hole 5 is 72 mm away from the center of the motor shaft.

[0042] A magnetic barrier 7 above the long permanent magnet is arranged in the V-shaped magnetic steel groove on the air gap side of the long permanent magnet 6, and a magnetic barrier 4 above the short permanent magnet is arranged in the V-shaped magnetic steel groove on the air gap side of the short permanent magnet 2.

[0043] A magnetic barrier 8 under the permanent magnet is arranged on each of the two straight slots of the V-shaped magnetic steel slot close to the center of the motor, and the magnetic barriers 8 under the two permanent magnets are not connected.

[0044] This embodiment is designed for the anti-demagnetization of the asymmetric built-in V permanent magnet synchronous motor. Two anti-demagnetization holes are set on the motor rotor laminations. Due to the particularity of the asymmetric motor, an asymmetric single-sided pole-cut anti-demagnetization magnet structure is designed at the magnetic steel. The two types of anti-demagnetization holes are set on the dq axis of the motor respectively, and the permanent magnet is pole-cut on one side.

[0045] By means of the above-mentioned single-sided pole clipping of the permanent magnet, the cooperation between the circular anti-demagnetization hole and the heart-shaped anti-demagnetization hole, the present invention not only maintains the same torque as before optimization and reduces torque pulsation, but also increases the critical demagnetization temperature of the permanent magnet, enhances the anti-demagnetization ability of the asymmetric permanent magnet synchronous motor, improves the reliability of the motor and saves costs to the greatest extent while reducing the amount of permanent magnet used.

[0046] Although the present invention is described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the present invention. It should therefore be understood that many modifications may be made to the exemplary embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that the various dependent claims and features described herein may be combined in a manner different from that described in the original claims. It should also be understood that the features described in conjunction with a single embodiment may be used in other described embodiments.

Claims

1. An asymmetric permanent magnet motor anti-demagnetization rotor topology structure, characterized in that: The invention comprises a rotor core (1), wherein a V-shaped magnetic steel slot is provided under each pole of the rotor core (1), the permanent magnet in each V-shaped magnetic steel slot adopts an asymmetric magnetic steel structure, a long permanent magnet (6) and a short permanent magnet (2) are respectively placed inside two straight slots of the V-shaped magnetic steel slot, and the magnetization directions of the two permanent magnets are perpendicular to the extension direction of the magnetic steel slot; The long permanent magnet (6) is subjected to pole trimming treatment; the long permanent magnet (6) is pole trimmed in a trapezoidal single-side manner, and the trimming position is on the left side of the permanent magnet close to the air gap. The area of ​​the right-angled triangle trimmed by the trapezoidal single-side pole trimming is 1.9432 mm 2 , one of the right-angled sides is 6.94 mm long and the other right-angled side is 0.56 mm long.

2. According to claim 1, the asymmetric permanent magnet motor anti-demagnetization rotor topology structure is characterized in that: The rotor core (1) is formed by coaxially stacking a plurality of punching sheets.

3. According to claim 1, the asymmetric permanent magnet motor anti-demagnetization rotor topology structure is characterized in that: A heart-shaped anti-demagnetization hole (3) is arranged on the d-axis under each pole, the heart-shaped anti-demagnetization hole (3) is arranged in the opening of the V-shaped magnetic steel slot close to the air gap side, and the heart-shaped anti-demagnetization hole (3) penetrates the entire rotor core (1) along the axial direction.

4. According to claim 3, the asymmetric permanent magnet motor anti-demagnetization rotor topology structure is characterized in that: The radial width M3 of the heart-shaped anti-demagnetization hole (3) is 5.9 mm, and the tangential length M4 is 15.6 mm.

5. The asymmetric permanent magnet motor anti-demagnetization rotor topology structure according to claim 1, characterized in that: A circular anti-demagnetization hole (5) is arranged on the q-axis under each pole, the circular anti-demagnetization hole (5) is arranged between two adjacent V-shaped magnetic steel slots, and the circular anti-demagnetization hole (5) penetrates the entire rotor core (1) along the axial direction.

6. The asymmetric permanent magnet motor anti-demagnetization rotor topology structure according to claim 5, characterized in that: The radius R1 of the circular anti-demagnetization hole (5) is 5 mm, and the center of the circular anti-demagnetization hole (5) is 72 mm away from the center of the motor shaft.

7. The asymmetric permanent magnet motor anti-demagnetization rotor topology structure according to claim 1, characterized in that: A magnetic barrier (7) above the long permanent magnet is arranged in the V-shaped magnetic steel groove on the air gap side of the long permanent magnet (6), and a magnetic barrier (4) above the short permanent magnet is arranged in the V-shaped magnetic steel groove on the air gap side of the short permanent magnet (2).

8. The asymmetric permanent magnet motor anti-demagnetization rotor topology structure according to claim 7, characterized in that: A magnetic barrier (8) below the permanent magnet is respectively arranged on the two straight slots of the V-shaped magnetic steel slot close to the motor center side, and the two magnetic barriers (8) below the permanent magnet are not connected.

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