An excitation editable permanent magnet motor

Abstract

The application discloses an excitation editable permanent magnet motor which is composed of a rotor, an excitation editable permanent magnet, a stator core and an armature winding, and is characterized in that the excitation editable permanent magnet is composed of three kinds of hard magnetic alloy materials with different rare earth proportions which are combined and arranged according to the motor operating point requirements, and the excitation editable permanent magnet structure is formed through subtractive or additive manufacturing mode in the circumferential direction. Based on the change characteristics of the working point value of the permanent magnet in the traditional permanent magnet motor, the permanent magnet is divided into four sections in the circumferential direction with the same value change range of the working point, and the arrangement of the three kinds of hard magnetic alloy materials in the excitation editable permanent magnet in the circumferential direction is determined and the excitation editable permanent magnet structure is formed according to the principle that the average value of the working point value in the section is close to the working point value of the hard magnetic alloy material under the working condition. The motor can edit the excitation permanent magnet magnetic field in the motor, improve the output performance of the motor, and is suitable for electric vehicles, industrial robot joint driving and other application occasions which require high output torque and high efficiency.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of motor design and manufacturing, and particularly relates to an excitation editable permanent magnet motor. BACKGROUND

[0002] Permanent magnet synchronous motor relies on the coupling of armature magnetic field and rotating magnetic field excited by rotor permanent magnet to output stable torque, has the advantages of low manufacturing cost, high power factor and high torque density, becomes an important choice to replace traditional electrically excited motor, and is widely applied to fields such as aerospace, space exploration and industrial production. Among them, the ideal operating condition of permanent magnet synchronous motor is that the motor current with sinusoidal distribution interacts with the air gap magnetic field with sinusoidal distribution and outputs stable torque, although the permanent magnet synchronous motor adopting vector control can ensure the sinusoidal nature of motor current, however, the magnetic circuit characteristics of permanent magnet synchronous motor determine that the air gap magnetic field waveform is trapezoidal distribution. In order to reduce the iron loss and torque ripple of permanent magnet synchronous motor, it is necessary to keep the air gap magnetic field waveform with high sinusoidal nature in the motor design stage.

[0003] In order to solve the problem, researchers have proposed many schemes. Among them, the traditional way of changing the pole arc coefficient or skew pole of permanent magnet pole can improve the torque output performance of the motor and reduce the torque ripple, however, the change of ordinary permanent magnet pole arc coefficient may not meet the requirements of some high power density motor systems; the process of skew pole is complex, and it is difficult to realize skew pole when the motor core is short. U-shaped and V-shaped permanent magnet synchronous motor has the advantages of strong anti-demagnetization ability and low torque ripple, and is suitable for application occasions requiring low torque ripple and wide speed regulation range, however, the radial magnetic field component generated by the permanent magnet of this type is smaller under the same volume, and the leakage coefficient is relatively large.

[0004] The motor adopting Halbach permanent magnet array can realize sinusoidal air gap magnetic field distribution. Researchers propose a Halbach structure with unequal height magnetic poles, and establish a magnetic field analytical model of T-shaped magnetic pole motor, and through comparison with traditional Halbach magnetized magnetic pole and radial magnetized magnetic pole, it is found that T-shaped magnetic pole has the advantages of small torque ripple and large electromagnetic torque. Double-layer convex Halbach permanent magnet array is composed of two parallel magnetized permanent magnets per pole, and has the advantages of simple structure and strong overall performance. The above two kinds of permanent magnet structures can improve the output torque of the motor and reduce the torque ripple, however, the two structures increase the amount of permanent magnet, improve the manufacturing cost of the motor, and increase the risk of saturation of ferromagnetic material.

[0005] At present, optimizing permanent magnet structure and placement space can effectively improve the torque output performance of permanent magnet synchronous motor. However, due to the limited placement space of permanent magnet and the size of permanent magnet being restricted by other factors, simply designing in the placement space and size of permanent magnet will be greatly limited. According to the performance requirements of the permanent magnet synchronous motor, in order to improve the sinusoidal degree of the air gap magnetic field, the hard magnetic alloy materials with different rare earth proportions can be reasonably arranged without changing the shape of the permanent magnet synchronous motor and the space position of the permanent magnet, so as to improve the sinusoidal degree of the air gap magnetic field, and then realize the final effect of improving the motor output torque and reducing the torque ripple.

[0006] The application provides a magnetically excitable and editable permanent magnet motor, which can effectively improve the sinusoidal performance of the air gap magnetic field and reduce the output torque ripple of the motor. SUMMARY

[0007] In order to solve the above problems, the application discloses a permanent magnet synchronous motor which can edit the internal excitation permanent magnet magnetic field, target to increase the working harmonic of the air gap magnetic field, effectively reduce the non-working harmonic and harmonic distortion, improve the output performance of the motor, and reduce vibration and noise.

[0008] In order to achieve the above purpose, the technical scheme of the application is as follows:

[0009] The magnetically excitable and editable permanent magnet motor comprises a rotor, a magnetically excitable and editable permanent magnet and a stator, wherein the rotor comprises a shaft and a rotor core, the stator comprises a stator core and an armature winding, and the magnetically excitable and editable permanent magnet comprises three kinds of hard magnetic alloy permanent magnet materials, namely N42SH, N38SH and N33SH, which are arranged in a circumferential array on the surface of the rotor core.

[0010] The magnetically excitable and editable permanent magnet is composed of three kinds of hard magnetic alloy materials with different rare earth proportions and is arranged according to the distribution and combination of the working points of the permanent magnet, so that the magnetic field of the internal permanent magnet excitation of the motor can be edited, the harmonic distribution of the air gap magnetic field can be targeted adjusted, the working harmonic can be increased, and the harmonic distortion can be reduced.

[0011] Further, according to the design requirements of the motor, the permanent magnet motor is designed and the primary permanent magnet structure is determined, the primary permanent magnet is divided into four sections with equal value change range of the working points in the circumferential direction based on the actual working point change characteristics of the permanent magnet, the arrangement of the three kinds of hard magnetic alloy materials in the circumferential direction is determined according to the principle that the difference between the average value of the working point value change in the section and the working point value of the hard magnetic alloy material under the working condition is minimum, the edited excitation permanent magnet of the combination is formed and manufactured to replace the primary permanent magnet structure, and the magnetically excitable and editable permanent magnet motor is formed.

[0012] Further, the excitation editable permanent magnet can be designed by using a non-equal numerical variation range segmentation method, which determines the distribution structure of the hard magnetic alloy material in the circumferential, radial and axial directions of the whole permanent magnet region according to the numerical variation of the actual working point, and uses the laser sintering method to form the permanent magnet by one-time additive manufacturing, thereby improving the design freedom of the motor and flexibly editing the excitation.

[0013] Further, the excitation editable permanent magnet is arranged according to the number of segments of the circumferential working point equal numerical variation range of the one-time formed permanent magnet, wherein in subtractive manufacturing, the number of segments is selected according to the processing technology and the number of selected materials, and is usually less than 6; in additive manufacturing, the material arrangement is determined according to the actual working point numerical variation without considering the influence of the number of segments.

[0014] Further, the distribution of the three kinds of hard magnetic alloy permanent magnetic materials in the permanent magnets at different axial positions in the excitation editable permanent magnet can be continuous and same

[0015] Further, the excitation editable permanent magnet can be in the form of surface-mounted, built-in and Halbach, and can be formed by subtractive manufacturing and bonding.

[0016] Further, the excitation editable permanent magnet can be composed of a plurality of hard magnetic materials with different alloy proportions, including materials with the same material, different content proportions and materials with different materials and different content proportions (the excitation editable permanent magnet generally uses NdFeB, but the permanent magnet can also use other permanent magnetic materials).

[0017] Further, the excitation editable permanent magnet is suitable for rotor permanent magnet motors and stator permanent magnet motors.

[0018] Further, the excitation editable permanent magnet motor adopts fractional slot concentrated winding.

[0019] The beneficial effects of the present application are:

[0020] (1) High output torque and low torque ripple. The excitation editable permanent magnet motor can edit the internal excitation permanent magnet magnetic field, target to increase the air gap magnetic field working harmonic, effectively reduce the non-working harmonic and harmonic distortion, and improve the output performance of the motor.

[0021] (2) High stability. The excitation editable permanent magnet motor can effectively reduce the non-working harmonic and harmonic distortion, improve the output performance of the motor, and reduce the vibration noise.

[0022] (3) High applicability. The excitation editable permanent magnet is suitable for rotor permanent magnet motors and stator permanent magnet motors, and has a very broad industrial application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1is a cross-sectional structure diagram of an excitation editable permanent magnet motor along an axis provided by an embodiment of the present application;

[0024] Figure 2 is a radial cross-sectional structure diagram of an excitation editable permanent magnet motor provided by an embodiment of the present application;

[0025] Figure 3 is a radial cross-sectional structure diagram of an excitation editable permanent magnet motor provided by an embodiment of the present application, wherein the excitation editable permanent magnet is formed by additive manufacturing;

[0026] Figure 4 is a three-dimensional structure diagram of a rotor and an excitation editable permanent magnet of an excitation editable permanent magnet motor provided by an embodiment of the present application.

[0027] In the figure: 1-rotor, 101-shaft, 102-rotor core, 2-excitation editable permanent magnet, 201-N42SH, 202-N38SH, 203-N33SH, 3-stator, 301-stator core, 302-armature winding. DETAILED DESCRIPTION

[0028] The present application will be further illustrated in conjunction with the accompanying drawings and specific embodiments, and it should be understood that the following specific embodiments are only used to illustrate the present application and not to limit the scope of the present application.

[0029] As shown in Figure 1 and Figure 2 , the present application discloses an excitation editable permanent magnet motor, which comprises a rotor 1, an excitation editable permanent magnet 2 and a stator 3, wherein the rotor 1 comprises a shaft 101 and a rotor core 102, the stator 3 comprises a stator core 301 and an armature winding 302, and the excitation editable permanent magnet 2 comprises three kinds of hard magnetic alloy permanent magnet materials of N42SH type permanent magnet 201, N38SH type permanent magnet 202 and N33SH type permanent magnet 203, which are arranged in a circumferential array on the surface of the rotor core 102.

[0030] As shown in Figure 2 , the excitation editable permanent magnet 2 is composed of three kinds of hard magnetic alloy materials with different rare earth proportions arranged according to the working point distribution of the permanent magnet, which can edit the magnetic field of the permanent magnet excitation in the motor, target to adjust the harmonic distribution of the air gap magnetic field, increase the working harmonic and reduce the harmonic distortion.

[0031] As shown in Figure 2As shown, the permanent magnet motor is designed according to the motor design requirements and the one-time forming permanent magnet structure is determined, based on the actual working point variation characteristics of the permanent magnet, the one-time forming permanent magnet is divided into four sections with equal numerical variation range in the circumferential direction, and the arrangement of the three hard magnetic alloy materials in the circumferential direction is determined according to the principle that the difference between the average value of the working point numerical variation in the section and the working point numerical value of the hard magnetic alloy material under the working condition is minimum, the edited excitation permanent magnet is formed and manufactured to replace the one-time forming permanent magnet structure, and the excitation editable permanent magnet motor is formed.

[0032] As shown in Figure 2 and Figure 4 , the excitation editable permanent magnet 2 can be designed by using the non-equal numerical variation range segmentation method, which determines the distribution structure of the hard magnetic alloy material powder in the whole permanent magnet region in the circumferential, radial and axial directions according to the actual working point numerical variation, and uses laser sintering to form the permanent magnet by one-time additive manufacturing, which improves the freedom of motor design and flexibly edits the excitation.

[0033] As shown in Figure 4 , the distribution of the three hard magnetic alloy permanent materials in the permanent magnet at different axial positions in the excitation editable permanent magnet 2 can be continuous and the same.

[0034] As shown in Figure 2 and Figure 3 , the excitation editable permanent magnet 2 is arranged according to the number of sections with equal numerical variation range of working points in the circumferential direction of the one-time forming permanent magnet, and the number of sections is usually less than 6 in subtractive manufacturing according to the processing technology and the number of selected materials, and the excitation editable permanent magnet 2 described in the present application is formed by wire cutting, only three materials are used, so the number of sections is small; additive manufacturing needs to sinter metal powder by laser, and the material arrangement is determined according to the actual working point numerical variation, without considering the influence of the number of sections.

[0035] As shown in Figure 2 , the excitation editable permanent magnet 2 can be in the form of surface-mounted, built-in and Halbach, and can be formed by subtractive manufacturing and bonding.

[0036] As shown in Figure 2 , the excitation editable permanent magnet 2 can be composed of a plurality of hard magnetic materials with different alloy proportions, including materials with the same material, different content proportions and different materials with different content proportions.

[0037] As shown in Figure 2 , the excitation editable permanent magnet 2 is suitable for rotor permanent magnet motors and stator permanent magnet motors.

[0038] As shown in Figure 2As shown, the armature winding 302 adopts a fractional-slot concentrated winding, which is wound on the stator teeth. In this embodiment, since the fractional-slot concentrated winding end is shorter than the traditional distributed winding end, the copper loss is low, which is conducive to reducing the temperature rise of the motor under load.

[0039] When the motor is unloaded, the excitation editable permanent magnet motor has a higher sinusoidal unloaded back electromotive force waveform; when the motor is loaded, the excitation editable permanent magnet motor can edit the internal excitation magnetic field of the motor, target to increase the working harmonic of the air gap magnetic field, effectively reduce the non-working harmonic, improve the output performance of the motor, reduce the vibration noise, and be suitable for electric vehicles, industrial robot joint driving and other application occasions requiring high output torque and high efficiency.

[0040] It should be noted that the above content only illustrates the technical idea of the present application, and cannot limit the protection scope of the present application. For ordinary skilled persons in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, which fall within the protection scope of the claims of the present application.

Claims

1. An editably excited permanent magnet electric machine, which machine comprises a rotor (1), editably excited permanent magnets (2) and a stator (3), wherein, The rotor (1) comprises a shaft (101) and a rotor core (102), the excitation editable permanent magnet (2) comprises three kinds of hard magnetic alloy permanent magnet materials of N42SH (201), N38SH (202) and N33SH (203), the excitation editable permanent magnet (2) is arranged in a circular array on the surface of the rotor core (102), and the stator (3) comprises a stator core (301) and an armature winding (302); The excitation editable permanent magnet (2) is composed of three kinds of hard magnetic alloy materials with different rare earth proportions and is arranged according to the working point distribution of the permanent magnet, the magnetic field of the permanent magnet excitation in the motor is edited, the target adjustment of the air gap magnetic field harmonic distribution is performed, the working harmonic is increased, and the harmonic distortion is reduced. According to the motor design requirements, the permanent magnet motor is designed and the one-time forming permanent magnet structure is determined, the one-time forming permanent magnet is divided into four sections with equal numerical value variation ranges in the circumferential direction based on the actual working point variation characteristics of the permanent magnet, the four sections are composed of N42SH (201), N38SH (202) and N33SH (203), the arrangement of the three kinds of hard magnetic alloy materials in the circumferential direction is determined according to the principle that the difference between the average value of the working point numerical value variation in a certain section and the working point numerical value of the hard magnetic alloy material under the working condition is minimum, the editing excitation permanent magnet is one-time formed by manufacturing, and the excitation editable permanent magnet motor is formed.

2. An editably excited permanent magnet electric machine according to claim 1, characterized in that: The excitation editable permanent magnet (2) is designed by using a non-equal numerical value variation range segmentation method, the distribution structure of the hard magnetic alloy material powder in the whole permanent magnet region is determined according to the actual working point numerical value variation, the permanent magnet is one-time formed by additive manufacturing in a laser sintering mode, the motor design freedom is improved, and the excitation is edited flexibly.

3. An edit-while-excited permanent magnet motor according to claim 1, characterized in that: The excitation editable permanent magnet (2) is arranged according to the number of sections with equal numerical value variation ranges of the working point of the one-time forming permanent magnet in the circumferential direction, wherein in subtractive manufacturing, the number of sections is selected according to the machining process and the number of selected materials, and must be less than 6; in additive manufacturing, the number of sections is not considered, and the material arrangement is determined according to the actual working point numerical value variation.

4. The field-editable permanent magnet motor of claim 1, wherein: The distribution of the three kinds of hard magnetic alloy permanent magnet materials in the permanent magnets at different axial positions in the excitation editable permanent magnet (2) can be continuous and same.

5. The field-editable permanent magnet motor of claim 1, wherein: The excitation editable permanent magnet (2) can be in a surface-mounted type, an embedded type and a Halbach type, and is formed by subtractive manufacturing and bonding.

6. The field-editable permanent magnet motor of claim 1, wherein: The excitation editable permanent magnet (2) is composed of a plurality of hard magnetic materials with different alloy proportions, which are composed of the same materials, materials with different content proportions, or materials with different materials and content proportions.

7. The field-editable permanent magnet motor of claim 1, wherein: The excitation editable permanent magnet (2) is suitable for rotor permanent magnet motors and stator permanent magnet motors.

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