Spoke type magnetic field modulation permanent magnet motor with low permanent magnet eddy current loss

Abstract

The utility model discloses a spoke type magnetic field modulation permanent magnet motor with low permanent magnet eddy current loss. Comprising an armature winding, a stator, a rotor, permanent magnets and a magnetic flux barrier, each permanent magnet is composed of a spoke type permanent magnet and two auxiliary permanent magnets, the magnetization directions of every two adjacent spoke type permanent magnets are the same, and the overall structure is in an inverted T shape. According to the utility model, the permanent magnets are designed in a segmented manner, and the magnetic flux barrier is additionally arranged in the rotor, so that the non-working harmonic amplitude which generates the eddy current loss of the permanent magnets is reduced, and the eddy current loss of the permanent magnets is effectively inhibited on the basis of ensuring the torque performance of the motor; the problem of over-high permanent magnet eddy current loss caused by rich harmonic waves in a magnetic field modulation permanent magnet motor is successfully solved, the risks of permanent magnet demagnetization and winding insulation burning are reduced, and the running reliability of the motor is improved.

Description

Technical Field

[0001] The utility model specifically relates to a spoke-type magnetic field modulation permanent magnet motor with low permanent magnet eddy current loss, belonging to the field of motor design. Background Art

[0002] In recent years, spoke motors have attracted widespread attention due to their high torque density and high utilization rate of permanent magnets. Spoke magnetic field modulation motors have better torque performance than traditional spoke motors. However, their magnetic field modulation effect will also cause rich harmonic components in the motor. These harmonics of different speeds and directions will move relative to the rotor, thereby generating a large amount of eddy current losses. Excessive eddy current loss of permanent magnets will cause the temperature of permanent magnets to rise, which may cause irreversible demagnetization of permanent magnets, seriously affecting the performance of the motor. Therefore, it is of great significance to design a suitable structure to suppress the eddy current loss of permanent magnets in magnetic field modulation motors. For magnetic field modulation motors with spoke-shaped arrays of permanent magnets, the magnetic lines of force are densely distributed. In order to effectively suppress the eddy current loss of permanent magnets and improve the efficiency of the motor while maintaining the torque performance of the motor, this type of research is very necessary. Utility Model Content

[0003] The purpose of the utility model is to propose a spoke-type magnetic field modulation permanent magnet motor with low permanent magnet eddy current loss, which can solve the problem of excessive eddy current loss of permanent magnets caused by rich harmonics in magnetic field modulation motors, and the torque performance of the motor is almost unaffected, thereby improving the reliability of motor operation.

[0004] In order to solve the above technical problems, the utility model adopts the following technical scheme: a spoke-type magnetic field modulation permanent magnet motor with low permanent magnet eddy current loss, comprising a stator, a rotor, an armature winding, a spoke-type permanent magnet, an auxiliary permanent magnet and a flux barrier; wherein the stator is composed of a stator core and an armature winding, the stator core is slotted to form a tooth slot structure, and the winding is wound in the tooth slot; the rotor is composed of a rotor core and a permanent magnet, the permanent magnet is embedded in the rotor, and is composed of a spoke-type permanent magnet and two auxiliary permanent magnets, and the whole presents an inverted T shape, and the magnetization directions of two adjacent spoke-type permanent magnets are the same; the rotor is in the middle of the stator, and there is an air gap between the stator and the rotor; the flux barrier is composed of two parts, which are respectively located on both sides and below the spoke-type permanent magnet.

[0005] Furthermore, the stator core and the rotor core are both made of silicon steel sheets or magnetic conductive materials with good magnetic properties; the permanent magnets use rare earth permanent magnets with large residual magnetism and coercive force, which can ensure that the motor has a higher torque density; the armature winding uses copper wire with lower resistance to avoid high copper loss, thereby reducing the risk of electromagnetic performance degradation due to motor overheating.

[0006] Furthermore, the number of slots of the stator and the number of pole pairs of the permanent magnets can be determined by the number of spokes and the winding coefficient.

[0007] Furthermore, the armature winding adopts a five-phase winding design.

[0008] Furthermore, the permanent magnet structure is an inverted T-shape, which is composed of a spoke-type permanent magnet and two auxiliary permanent magnets.

[0009] Furthermore, the magnetization directions of the adjacent spoke-type permanent magnets are the same, and the auxiliary permanent magnets have no direct contribution to the torque. Their function is to prevent the magnetic flux of the spoke-type permanent magnets from passing through the rotor yoke.

[0010] Furthermore, the permanent magnet segmentation design divides the spoke permanent magnet into two segments along the radial direction and divides the auxiliary permanent magnet into two segments along the circumferential direction, which is used to limit the eddy current path to suppress the eddy current loss of the permanent magnet.

[0011] Furthermore, the function of the magnetic flux barrier is to reduce the amplitude of non-operating harmonics that generate eddy current losses of permanent magnets, thereby effectively suppressing eddy current losses of permanent magnets while ensuring the torque performance of the motor.

[0012] After the utility model adopts the above design scheme, it can have the following beneficial effects:

[0013] 1. The problem of excessive eddy current loss of permanent magnets caused by rich modulation harmonics in magnetic field modulation motors is solved.

[0014] 2. By designing a flux barrier in the rotor, the amplitude of the non-operating harmonics that generate eddy current losses of the permanent magnets is reduced, thereby effectively suppressing the eddy current losses of the permanent magnets while ensuring the torque performance of the motor.

[0015] 3. It solves the contradiction between suppressing motor loss and ensuring motor torque performance, reduces the risk of permanent magnet demagnetization in magnetic field modulation motors, and improves the reliability of motor operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is the structural topology diagram of the magnetic field modulation permanent magnet motor with low permanent magnet eddy current loss in the utility model.

[0017] Figure 2 This is a parameter model diagram of the magnetic field modulation permanent magnet motor with low permanent magnet eddy current loss in the utility model.

[0018] Figure 3 This is a permanent magnet magnetizing direction diagram of the magnetic field modulation permanent magnet motor with low permanent magnet eddy current loss in the utility model.

[0019] Figure 4This is a comparison chart of the air gap flux density harmonic spectra of the magnetic field modulation permanent magnet motor with medium and low permanent magnet eddy current loss in the utility model and the traditional magnetic field modulation motor.

[0020] Figure 5 This is a comparison chart of the eddy current loss of permanent magnets of the magnetic field modulation permanent magnet motor with medium and low permanent magnet eddy current loss in the utility model and the traditional magnetic field modulation motor.

[0021] Figure 6 This is a torque performance comparison diagram of the magnetic field modulation permanent magnet motor with low permanent magnet eddy current loss in the utility model and the traditional magnetic field modulation motor. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0023] The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0024] As attached Figure 1 As shown, the utility model proposes a spoke-type magnetic field modulation permanent magnet motor with low permanent magnet eddy current loss, the motor comprises a stator 1, a rotor 2, an armature winding 3, a spoke-type permanent magnet 4, an auxiliary permanent magnet 5 and a flux barrier 6; wherein the stator 1 is composed of a stator core and an armature winding 3, the stator core is slotted to form a tooth slot structure, and the armature winding 3 is wound in the tooth slot; the rotor 2 is composed of a rotor core and a permanent magnet, the permanent magnet is embedded in the rotor, and is composed of a spoke-type permanent magnet 4 and two auxiliary permanent magnets 5, and the whole presents an inverted T shape, and the magnetization directions of two adjacent spoke-type permanent magnets 4 are the same; the rotor 2 is in the middle of the stator 1, and there is an air gap between the stator 1 and the rotor 2; the flux barrier 6 is composed of two parts, which are respectively located on both sides and below the spoke-type permanent magnet 4. Among them, the stator core and the rotor core are both made of silicon steel sheets or magnetic conductive materials with good magnetic conductivity; the permanent magnets use rare earth permanent magnets with large residual magnetism and coercive force, which can ensure that the motor has a higher torque density; the armature winding 3 uses copper wire with lower resistance to avoid high copper loss.

[0025] As attached Figure 2 As shown in the figure, Bs0 is the opening width of the stator slot, Hs2 is the height of the stator slot body, Rbs0 is the opening width of the rotor slot, Rhs0 is the opening height of the rotor slot, Rhs1 is the height of the rotor slot wedge, width is the width of the auxiliary permanent magnet, and hb is the width of the spoke permanent magnet. When the inner and outer diameters and axial length of the stator remain unchanged, the above main parameters need to be optimized to obtain the optimal electromagnetic performance under the motor structure.

[0026] As attached Figure 3As shown, the magnetization direction of the spoke-type permanent magnet 4 is along the circumferential direction, and the magnetization directions of adjacent spoke-type permanent magnets 4 are the same; the magnetization direction of the auxiliary permanent magnet 5 is along the radial direction, and the magnetization directions of two adjacent auxiliary permanent magnets 5 are opposite. The auxiliary permanent magnet 5 has no direct contribution to the torque, and its function is to prevent the magnetic flux of the spoke-type permanent magnet 4 from passing through the rotor yoke.

[0027] Attached Figure 4 Comparative analysis of the air gap flux density harmonic spectrum of the magnetic field modulation motor before and after the rotor flux barrier is added. It can be seen that the newly proposed low permanent magnet eddy current loss magnetic field modulation motor can effectively reduce the first-order spatial harmonic in the air gap flux density, and the first-order harmonic in the air gap is the main non-working harmonic that produces permanent magnet eddy current loss. Therefore, it can be inferred that the introduction of the rotor flux barrier can effectively suppress the permanent magnet eddy current loss.

[0028] Attached Figure 5 Comparison of simulation results of permanent magnet eddy current loss before and after adding rotor flux barrier and adopting segmented design for permanent magnet. Compared with the original magnetic field modulation motor, the eddy current loss in the newly proposed low permanent magnet eddy current loss magnetic field modulation motor is significantly reduced, which is reduced by 81.6% compared with the original.

[0029] Attached Figure 6 This is a comparison chart of the torque and torque pulsation of the newly proposed low permanent magnet eddy current loss magnetic field modulation motor and the original magnetic field modulation motor. It can be seen that after adding the rotor flux barrier, the average torque of the new machine has not decreased, and the torque pulsation is slightly improved compared with the original machine.

[0030] In summary, the utility model discloses a spoke-type magnetic field modulation permanent magnet motor with low permanent magnet eddy current loss, which reduces the amplitude of non-operating harmonics that generate permanent magnet eddy current loss by adding a magnetic flux barrier in the rotor, and adopts a block design for the permanent magnet, thereby effectively suppressing the permanent magnet eddy current loss on the basis of ensuring the motor torque performance. The problem of excessive permanent magnet eddy current loss caused by abundant harmonics in magnetic field modulation permanent magnet motors is successfully solved, the risk of permanent magnet demagnetization and winding insulation burning is reduced, and the reliability and efficiency of motor operation are improved.

[0031] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0032] Although the embodiments of the present invention have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A spoke-type magnetic field modulation permanent magnet motor with low permanent magnet eddy current loss, characterized in that: The motor comprises a stator (1), a rotor (2), an armature winding (3), a spoke-type permanent magnet (4), an auxiliary permanent magnet (5) and a magnetic flux barrier (6); wherein the stator (1) is composed of a stator core and an armature winding (3), the stator core is slotted to form a tooth slot structure, and the armature winding (3) is wound in the tooth slot; the rotor (2) is composed of a rotor core and a permanent magnet, the permanent magnet is embedded in the rotor, and is composed of a spoke-type permanent magnet (4) and two auxiliary permanent magnets (5), and the whole presents an inverted T shape, and the magnetization directions of two adjacent spoke-type permanent magnets (4) are the same; the rotor (2) is in the middle of the stator (1), and there is an air gap between the stator (1) and the rotor (2); the magnetic flux barrier (6) is composed of two parts, which are respectively located on both sides and below the spoke-type permanent magnet (4).

2. The motor according to claim 1, characterized in that: The stator core and the rotor core are both made of silicon steel sheets or magnetic conductive materials with good magnetic conductivity; the permanent magnets use rare earth permanent magnets with large residual magnetism and coercive force to ensure that the motor has a high torque density; the armature winding (3) uses copper wire with low resistance.

3. The motor according to claim 1, characterized in that: The number of slots of the stator (1) and the number of pole pairs of the permanent magnets are determined by the number of spokes and the winding coefficient.

4. The motor according to claim 1, characterized in that: The armature winding (3) adopts a five-phase winding design.

5. The motor according to claim 1, characterized in that: The permanent magnet structure is an inverted T-shape and is composed of a spoke-type permanent magnet (4) and two auxiliary permanent magnets (5).

6. The motor according to claim 1, characterized in that: The magnetization directions of adjacent spoke-type permanent magnets (4) are the same. The auxiliary permanent magnets (5) do not contribute directly to the torque, and their function is to prevent the magnetic flux of the spoke-type permanent magnets (4) from passing through the rotor yoke.

7. The motor according to claim 1, characterized in that: The permanent magnet segmentation design is to divide the spoke-type permanent magnet (4) into two segments along the radial direction, and to divide the auxiliary permanent magnet (5) into two segments along the circumferential direction.

8. The motor according to claim 1, characterized in that: The magnetic flux barrier (6) is used to reduce the amplitude of non-operating harmonics that generate eddy current losses of permanent magnets, thereby effectively suppressing the eddy current losses of permanent magnets while ensuring the torque performance of the motor.

Images