Stator double-permanent-magnet flux reverse motor

Abstract

The invention discloses a stator double-permanent-magnet flux reverse motor, and belongs to the technical field of motors. The motor comprises a stator, a rotor, tangential permanent magnets, Halbach array permanent magnets and windings, the stator is of a double-salient-pole structure formed by combining T-shaped stator iron core blocks. The rotor and the stator are coaxially assembled, and an air gap is reserved between the rotor and the stator. The tangential permanent magnets are installed between the stator iron core blocks and magnetized in the tangential direction, and the adjacent directions are opposite. The Halbach permanent magnets are arranged at the openings of the stator slots, so that the Halbach permanent magnets have a magnetism gathering effect and can provide relatively high air gap flux density; the winding adopts a double-layer centralized design and is embedded into a stator slot; the tangential permanent magnets and the Halbach permanent magnets form a parallel magnetic circuit, and the air gap flux density and the torque density are improved through magnetic field superposition; the number of winding pole pairs meets a specific formula, and the motor structure can be optimized through a finite element method. Compared with a traditional motor, the motor has higher air gap flux density, no-load back electromotive force and torque, lower torque pulsation and a higher power factor, and the electromagnetic performance and the operation stability are remarkably improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electric machines, in particular to a stator double permanent magnet flux reversal motor. BACKGROUND

[0002] The flux reversal motor is particularly suitable for scenarios with high starting torque requirements due to its ability to output high torque at low speeds, and has been widely used in the field of mechanical equipment such as pumps, compressors, and fans that bear heavy loads. However, with the continuous progress of science and technology and the upgrading of industrial demand, the requirements for motor performance are increasing, especially in terms of efficiency, power density, torque output capacity, and speed regulation performance. The structural design and technical solutions of traditional flux reversal motors have gradually exposed many shortcomings.

[0003] In recent years, researchers have proposed a variety of flux reversal motors with different structures, including double stator, double rotor, linear, and axial types, to meet higher performance standards. Although these improvements have improved motor performance to some extent, there are still some problems, such as overly complex structural design, significant torque pulsation during operation, and insufficient fault tolerance capability. These problems limit the widespread application of flux reversal motors in high-precision technology fields.

[0004] Therefore, how to improve the reliability and electromagnetic performance of flux reversal motors has become a technical problem that needs to be solved urgently. SUMMARY

[0005] The purpose of the present application is to provide a stator double permanent magnet flux reversal motor to solve the above technical problems existing in the prior art.

[0006] To achieve the above purpose, the present application provides the following solution: a stator double permanent magnet flux reversal motor, comprising a stator, a rotor, tangential permanent magnets, Halbach permanent magnets, and windings; the stator is composed of a plurality of T-shaped stator core blocks combined in the circumferential direction, forming a double salient structure; the rotor is coaxially assembled with the stator, adopts a double salient structure, and has an air gap between the stator; the tangential permanent magnets are installed between adjacent T-shaped stator core blocks, magnetized along the tangential direction, and the magnetization directions of adjacent tangential permanent magnets are opposite; the Halbach permanent magnets are arranged at the openings of the stator slots, have a magnetic concentration effect, and can provide a high air gap flux density; the windings adopt double-layer concentrated windings embedded in the stator slots; the tangential permanent magnets and the Halbach permanent magnets form a parallel magnetic circuit, and the air gap flux density and torque density are improved through magnetic field superposition.

[0007] The structure aims to provide a stator double-permanent-magnetic flux reversal motor, which forms a parallel magnetic circuit through tangential permanent magnets and Halbach permanent magnets, significantly improves air gap flux and torque density, enhances electromagnetic performance and operation stability of the motor, and is suitable for low-speed high-torque scenes.

[0008] Further, the Halbach permanent magnet is composed of three single magnets, including a first single magnet, a second single magnet and a third single magnet sequentially attached, the first single magnet and the third single magnet are the same in shape and size; in the same magnetic pole, the magnetization directions of the first single magnet and the third single magnet are both tangential outward, and the magnetization direction of the second single magnet is radial outward; in adjacent magnetic poles, the magnetization directions of the two first single magnets and the third single magnet are both tangential inward, and the magnetization directions of the two second single magnets are radial inward.

[0009] Further, the pole pair number P of the winding satisfies the following formula:

[0010]

[0011] Wherein, i is the permanent magnetic field harmonic number, Z S is the stator slot number, Z r is the rotor slot number.

[0012] The pole pair number of the winding satisfies a specific formula, which can optimize the magnetic field distribution of the motor and further improve the efficiency and power density of the motor.

[0013] Further, the winding is a concentrated armature winding or a distributed armature winding, which can be flexibly selected according to the specific application scene of the motor, improving the adaptability and design flexibility of the motor.

[0014] Further, the winding is a single-layer winding or a double-layer winding, which increases the diversity of winding design and helps to optimize the electromagnetic performance and heat dissipation performance of the motor.

[0015] Further, in order to form a symmetrical winding, the stator slot number of the motor should satisfy the following formula:

[0016]

[0017] Wherein, Z s is the stator slot number, P is the pole pair number of the winding, m is the phase number, and GCD is the greatest common divisor of Z s and P.

[0018] Further, the materials of the stator and the rotor are silicon steel sheets, and the winding is made of enameled wire, which ensures high magnetic permeability and low loss of the motor, and at the same time improves the efficiency and reliability of the motor.

[0019] Further, the structure parameters of the motor are globally optimized by the finite element method, including the tangential permanent magnet thickness, the stator slot opening coefficient, the rotor slot opening coefficient and the yoke width. By globally optimizing the structure parameters of the motor by the finite element method, the motor can achieve the best performance under various working conditions, and the efficiency, power density and reliability of the motor are improved.

[0020] Further, the stator slot opening coefficient is 0.61, the rotor slot opening coefficient is 0.69, and the yoke width is 10.2 mm. The optimized stator slot opening coefficient, rotor slot opening coefficient and yoke width can further reduce the loss of the motor and improve the efficiency and power factor of the motor.

[0021] Compared with the prior art, the present application at least discloses the following beneficial effects:

[0022] The stator double permanent magnet flux reversal motor of the present application achieves remarkable technical effects through unique structural design. First, the stator of the motor adopts a double salient structure composed of multiple T-shaped stator core blocks arranged circumferentially. This design not only enhances the overall mechanical strength of the motor, but also provides an optimized spatial layout for the installation of permanent magnets. Second, the tangential permanent magnets are installed between adjacent T-shaped stator core blocks, magnetized along the tangential direction and opposite in adjacent direction. This magnetization method causes the magnetic field to form effective superposition in the air gap, significantly enhancing the air gap flux density. Meanwhile, the Halbach permanent magnets are arranged at the stator slot openings, which have a magnetic concentrating effect and can provide higher air gap flux density, making the magnetic field energy more concentrated in the air gap area, thereby improving the torque density and power density of the motor. In addition, the winding adopts a double-layer concentrated design and is embedded in the stator slot. This winding layout improves the slot fill factor of the motor, reduces the winding resistance, and thus reduces copper loss and improves the efficiency of the motor. By forming parallel magnetic circuits with tangential permanent magnets and Halbach permanent magnets, the magnetic field superposition effect significantly improves the air gap flux density and torque density, and optimizes the electromagnetic performance of the motor. This structural design also reduces torque ripple, improves the stability and reliability of the motor operation, making it particularly suitable for low-speed high-torque application scenarios. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0024] Figure 1 The structure schematic diagram of the stator double permanent magnet flux reversal motor for embodiment 1 of the present application is shown in the figure.

[0025] Figure 2 Structure diagram of the permanent magnet motor with only stator slot opening for the present application comparative example 1;

[0026] Figure 3 Structure diagram of the permanent magnet motor with only stator yoke for the present application comparative example 2;

[0027] Figure 4 Structure diagram of the conventional flux reversal motor for the present application comparative example 3;

[0028] Figure 5 No-load magnetic circuit diagram for the present application example 1, comparative example 1 and comparative example 2;

[0029] Figure 6 No-load magnetic flux flow direction diagram for the present application example 1;

[0030] Figure 7 Air gap magnetic flux density comparison diagram for the present application example 1, comparative example 1 and comparative example 2;

[0031] Figure 8 Air gap magnetic flux density spectrum for the present application example 1, comparative example 1 and comparative example 2;

[0032] Figure 9 Counter electromotive force waveform comparison diagram for the present application example 1, comparative example 1-3;

[0033] Figure 10 Counter electromotive force spectrum for the present application example 1, comparative example 1-3;

[0034] Figure 11 Average torque comparison diagram for the present application example 1, comparative example 1-3.

[0035] In the figure: 1, stator; 2, tangential permanent magnet; 3, Halbach permanent magnet; 4, winding; 5, rotor; 6, T-shaped stator core block. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0037] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0038] Example 1

[0039] ReferenceFigure 1 As shown, the embodiment 1 of the present application provides a stator double permanent magnet flux reversal motor with 12 slots and 11 poles, which comprises a stator 1, tangential permanent magnets 2, Halbach permanent magnets 3, windings 4 and a rotor 5. Among them, the stator 1 is sleeved outside the rotor 5 and coaxially assembled with the rotor 5, and there is an air gap between the stator 1 and the rotor 5, and the rotor 5 and the stator 1 both adopt a double salient structure. Specifically, the stator 1 is composed of a plurality of T-shaped stator core blocks 6 combined in the circumferential direction to form a double salient structure; the rotor 5 is coaxially assembled with the stator 1 and adopts a double salient structure, leaving an air gap with the stator; the tangential permanent magnets 2 are installed between adjacent T-shaped stator core blocks 6 and magnetized in the tangential direction, and the magnetization directions of adjacent tangential permanent magnets 2 are opposite; the Halbach permanent magnets 3 are arranged at the stator slot openings to form a Halbach array, have a magnetic concentration effect, and can provide a higher air gap flux density; the windings 4 adopt double-layer concentrated windings embedded in the stator slots. In this embodiment, the design of double permanent magnet parallel magnetic circuit is adopted, and the magnetic field of the yoke tangential permanent magnet 2 and the slot Halbach permanent magnet 3 is superposed, which significantly improves the air gap flux density.

[0040] It should be understood that the Halbach permanent magnet 3 in the embodiment is a special arrangement of permanent magnet structure first proposed by Klaus Halbach, a German physicist, which is a combination of permanent magnets arranged in a Halbach array. This arrangement can significantly enhance the magnetic field in a certain direction and weaken or cancel it in other directions through a specific geometric layout, so as to achieve optimized distribution of the magnetic field. As a commonly used technical means in the art, it will not be described here.

[0041] In one specific embodiment, the Halbach permanent magnet 3 is composed of three single magnets, including a first single magnet, a second single magnet and a third single magnet sequentially attached, the first single magnet and the third single magnet are the same in shape and size; in the same magnetic pole, the magnetization directions of the first single magnet and the third single magnet are both tangential outward, and the magnetization direction of the second single magnet is radial outward; in adjacent magnetic poles, the magnetization directions of the two first single magnets and the third single magnets are both tangential inward, and the magnetization directions of the two second single magnets are both radial inward.

[0042] In one specific embodiment, in order to form a symmetrical winding, the number of stator slots of the motor should satisfy the following formula:

[0043]

[0044] Wherein, Z s is the number of stator slots, P is the number of winding pole pairs, m is the number of phases, and GCD is the greatest common divisor of Z s and P.

[0045] In order to verify the technical advantages of the stator dual permanent magnet flux reversal motor of Example 1 of the present invention, the following comparative examples were designed:

[0046] Comparative Example 1: A permanent magnet motor with only stator slots, the structure of which is as follows Figure 2 As shown, the motor is a stator slot permanent magnet motor of the same design specifications. The stator 1 and rotor 5 structures of the motor are consistent with those of Example 1. It should be noted that the motor does not have Halbach permanent magnets 3, but only retains tangential permanent magnets 2.

[0047] Comparative Example 2: A permanent magnet motor with only the stator yoke, the structure of which is as follows Figure 3 As shown, the motor is a stator yoke-only permanent magnet motor of the same design specifications. The stator 1 and rotor 5 structures of the motor are consistent with those of Example 1. It should be noted that the motor has no tangential permanent magnets 2 and only retains Halbach permanent magnets 3.

[0048] Comparative Example 3: Traditional flux reversal motor, its structure is as follows Figure 4 As shown, this motor is a conventional flux-reversing motor of the same design specifications. The permanent magnets of this motor are radially attached to the stator teeth. The magnetization directions of the permanent magnets are all radial, and the magnetization directions alternate in opposite directions. The stator 1 and rotor 5 structures of this motor are consistent with those of Example 1.

[0049] In a specific embodiment, in the motor structures described in Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3, the stator 1 and rotor 5 are both made of silicon steel sheets, and the winding 4 is made of enameled wire and adopts a double-layer centralized winding. The four motors have unified parameters: the number of stator slots, the number of rotor slots, the number of winding pole pairs, the outer radius, the shaft length, the speed, and the copper loss are consistent across all motors. See Table 1 for details:

[0050] Table 1

[0051]

[0052] In order to make a fair comparison, the four motors were globally optimized using the finite element method to achieve the optimal performance of each of the four motors. Table 2 lists the optimized parameters of the four motors:

[0053] Table 2

[0054]

[0055] In a specific embodiment, in order to more clearly illustrate the technical advantages of the present invention, the stator dual permanent magnet flux reversal motor of Example 1 is compared and analyzed with the performance of Comparative Example 1 (stator slot permanent magnet motor only), Comparative Example 2 (stator yoke permanent magnet motor only) and Comparative Example 3 (traditional flux reversal motor).

[0056] like Figure 5 As shown,Figure 5 The no-load magnetic circuit distribution of each motor is shown, where (a), (b), and (c) correspond to Example 1, Comparative Example 1, and Comparative Example 2, respectively. Figure 6 As can be seen from the magnetic flux flow diagram, the yoke permanent magnets and slot permanent magnets in Example 1 form two parallel magnetic circuits, resulting in a significant magnetic field superposition effect. This dual-permanent magnet parallel excitation structure effectively enhances the air gap flux density, thereby improving the motor's torque density and output power.

[0057] Figure 7 The air gap flux density waveforms of the three types of motors are compared. The waveform of Example 1 shows the superposition characteristics of the waveforms of Comparative Example 1 and Comparative Example 2, and its magnetic field harmonic distribution is as follows: Figure 8 As shown. According to the calculation formula of the number of winding pole pairs:

[0058]

[0059] Among them, P is the number of winding pole pairs, i is the harmonic order of the permanent magnetic field, Z S is the number of stator slots, Z r is the number of rotor slots.

[0060] The stator double permanent magnet flux reversal motor with magnetic field modulation can generate more working harmonics, which contribute to the torque. According to the winding characteristics, the stator double permanent magnet flux reversal motor with 12 slots and 11 poles can generate 6, 18 and 30 times (iZ S / 2, i=1,3,5) air gap magnetic density inherent harmonics.

[0061] It should be noted that these air gap magnetic flux harmonics are further generated by the modulation of the rotor teeth to generate the 5th, 7th, 17th, 19th and 29th harmonics (|iZ S / 2±Z r |)Effective operating harmonics.

[0062] like Figure 7 As shown, thanks to the enhanced sixth-order natural harmonic, the amplitude of the fifth-order main operating harmonic in Example 1 is significantly higher than that of the single permanent magnet motor. Specifically, its fifth-order harmonic amplitude is increased by 87.5% and 42.9% compared to Comparative Examples 1 and 2, respectively. This demonstrates that the dual permanent magnet design can optimize the operating harmonic content of the air gap magnetic field, thereby increasing the fundamental amplitude of the magnetic field density and the no-load back EMF.

[0063] On this basis, the stator dual permanent magnet flux reversal motor proposed in Example 1 of the present invention has richer magnetic flux harmonic components than the stator single permanent magnet motor, thereby generating a higher magnetic flux fundamental wave amplitude and no-load back electromotive force.

[0064] like Figure 9 and Figure 10 As shown, Figure 9 and Figure 10The back electromotive force test data of the back electromotive force of the embodiment 1 is increased by 59% and 33.6% compared with the comparative example 1 and the comparative example 2 respectively, and is increased by 12% compared with the traditional flux reversal motor (comparative example 3).

[0065] As shown in Figure 11 , Figure 11 is a comparison chart of load torque of four motors, Figure 11 The load torque performance of the four motors at 300 rpm is compared. The average torque of the embodiment 1 is increased by 77.2%, 39.8% and 24.1% respectively compared with the other three motors, and the torque ripple is reduced by 73%, 47.9% and 46.5% respectively.

[0066] By optimizing the design and combining the finite element method, the performance of the four motors is compared in detail under the same conditions of motor size, coil turns, material and speed. See Table 3. Compared with the stator single permanent magnet motor and the traditional flux reversal motor, the stator double permanent magnet flux reversal motor of the embodiment 1 has significant advantages in torque output, magnetic field utilization rate and running stability.

[0067] Table 3

[0068]

[0069] In the description of the present application, it should be understood that the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0070] The above-described embodiments are only preferred modes of the present application and do not limit the scope of the present application. Without departing from the design spirit of the present application, various modifications and improvements to the technical solutions of the present application made by those skilled in the art shall fall within the protection scope of the present application as defined by the claims.

Claims

1. A stator doubly salient flux reversal electric machine characterized in that, The application relates to a motor with a Halbach permanent magnet and a tangential permanent magnet. The motor comprises the following parts: a stator (1) formed by a plurality of T-shaped stator core blocks (6) combined in a circumferential direction to form a double salient structure; a rotor (5) coaxially assembled with the stator (1) and adopting a double salient structure and leaving an air gap between the stator (1); a tangential permanent magnet (2) installed between adjacent T-shaped stator core blocks (6) and magnetized in a tangential direction, and adjacent tangential permanent magnets (2) being magnetized in opposite directions; a Halbach permanent magnet (3) arranged at a stator slot opening; a winding (4) embedded in the stator slot and adopting a double-layer concentrated winding.

2. The stator doubly salient flux reversal electric machine of claim 1, wherein, The tangential permanent magnet (2) and the Halbach permanent magnet (3) form a parallel magnetic circuit to improve air gap magnetic flux density and torque density through magnetic field superposition. The Halbach permanent magnet (3) is composed of three single magnets, including a first single magnet, a second single magnet and a third single magnet sequentially attached, and the first single magnet and the third single magnet being identical in shape and size. In the same magnetic pole, the first single magnet and the third single magnet are both magnetized in a tangential direction outward, and the second single magnet is magnetized in a radial direction outward.

3. The stator doubly salient flux reversal electric machine of claim 1, wherein, In adjacent magnetic poles, the two first single magnets and the third single magnet are both magnetized in a tangential direction inward, and the two second single magnets are both magnetized in a radial direction inward. wherein i is the permanent magnetic field harmonic number, Z S is the number of stator slots, Z r is the number of rotor slots.

4. The stator doubly salient flux reversal electric machine of claim 1, wherein, The pole pair number P of the winding (4) satisfies the following formula:

5. The stator doubly salient flux reversal electric machine of claim 1 or 4, wherein, The winding (4) is a concentrated armature winding or a distributed armature winding.

6. The stator doubly-magnetized flux-reversal electric machine of claim 1, wherein, The winding (4) is a single-layer winding or a double-layer winding. wherein Z s is the number of stator slots, P is the number of winding pole pairs, m is the number of phases, GCD is the greatest common divisor of Z s and P.

7. The stator doubly-magnetized flux-reversal electric machine of claim 1, wherein, In order to form a symmetrical winding, the number of stator slots of the motor should satisfy the following formula:

8. The stator doubly-magnetized flux reversal electric machine of claim 1, wherein, The materials of the stator (1) and the rotor (5) are silicon steel sheets, and the winding (4) is made of enameled wire. The structure parameters of the motor are globally optimized by a finite element method, and the structure parameters include the thickness of the tangential permanent magnet, the stator slot opening coefficient, the rotor slot opening coefficient and the yoke width.

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