High-performance driving axial yoke-free segmented stator magnetic flux switching type permanent magnet motor

Abstract

The invention provides a high-performance driving axial yoke-free segmented stator magnetic flux switching type permanent magnet motor, which adopts an axial double-rotor-single-stator structure, rotors are coaxially arranged on two sides of a stator in parallel, the stator is composed of a plurality of separated modular stator units, the modular stator units are connected without stator yokes, and the modular stator units are connected with the single-rotor-single-stator structure. Each modular stator unit comprises a tangential magnetized permanent magnet and two iron cores clamping the permanent magnet, and armature windings are wound on the outer sides of the iron cores. According to the invention, through the combination of the yoke-free stator unit and the dual-rotor topology, the space limitation of a traditional magnetic flux switching permanent magnet motor winding is broken through, and the torque density is improved; the fractional-slot concentrated winding is adopted, so that copper loss is effectively reduced; the improved magnetic flux modulation principle and deviation angle design realize collaborative optimization of high torque and low pulsation.

Description

Technical Field

[0001] This invention belongs to the field of electric drive technology, specifically relating to a high-performance drive axial yokeless segmented stator flux switching permanent magnet motor. Background Technology

[0002] In existing technologies, flux-switching permanent magnet motors with stator permanent magnet structures have limited space in the armature windings and stator core due to the placement of the permanent magnets in the stator, making it difficult to further improve torque density and reduce torque ripple. While yokeless segmented stator axial flux motors offer the advantage of high torque density, their combination with flux-switching motors presents challenges in effective magnetic circuit design, leading to increased magnetic leakage and decreased electromagnetic performance. Furthermore, traditional methods for reducing torque ripple (such as stator skew slots and segmented permanent magnets) increase manufacturing complexity. Summary of the Invention

[0003] The main objective of this invention is to provide a high-performance permanent magnet motor with a yokeless segmented stator flux switching mechanism to address the aforementioned problems.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A high-performance drive axial yokeless segmented stator flux switching permanent magnet motor adopts an axial dual rotor-single stator structure. The rotors are arranged parallel and coaxially on both sides of the stator. The stator is composed of multiple separate modular stator units. There is no stator yoke connection between the modular stator units. Each modular stator unit includes a tangentially magnetized permanent magnet and two iron cores that clamp the permanent magnet. An armature winding is wound around the outside of the iron core.

[0006] While adopting the above technical solutions, the present invention may also adopt or combine the following technical solutions:

[0007] As a preferred technical solution of the present invention: the two rotor teeth are circumferentially offset by half a pole pitch angle, forming two parallel planar air gaps with the stator.

[0008] As a preferred technical solution of the present invention: the rotor has a salient pole structure with 22 teeth, and forms a magnetic field modulation relationship with the modular stator unit.

[0009] As a preferred embodiment of the present invention, the modular stator unit comprises 12 units.

[0010] As a preferred embodiment of the present invention, the armature winding adopts a fractional slot concentrated winding with a winding pole pair number of 4.

[0011] As a preferred technical solution of the present invention, the magnetic circuit path of the permanent magnet motor is: permanent magnet → iron core → upper air gap → upper rotor → upper air gap → iron core → another permanent magnet → iron core → lower air gap → lower rotor → lower air gap → iron core → the initial permanent magnet, forming a symmetrical ring circuit on both sides.

[0012] As a preferred technical solution of the present invention: the method for modulating the magnetic field of the permanent magnet motor is to add the constraint m·k≠1 to the following formula to adapt to the yokeless axial structure:

[0013] p r =mp a ±kp m (m = 1, 5, 7..., k = 1, 3, 5...)

[0014] In the formula, m and k are both parameter coefficients; p r p is the number of rotor teeth. a p is the number of pole pairs in the armature winding. m is the number of pole pairs of the permanent magnet.

[0015] As a preferred embodiment of the present invention, the rotor offset angle of the permanent magnet motor is designed as shown in the following formula.

[0016] α=γ / 2

[0017] In the formula, α is the offset angle of the dual rotors, and γ is the rotor pole pitch. Optimizing magnetic circuit coupling reduces motor torque ripple.

[0018] This invention provides a high-performance drive axial yokeless segmented stator flux-switching permanent magnet motor, which has the following advantages: This invention breaks through the winding space limitation of traditional flux-switching permanent magnet motors by combining yokeless stator units with dual rotor topology, thereby improving torque density; adopting fractional slot concentrated windings effectively reduces copper losses; and the improved flux modulation principle and offset angle design achieve synergistic optimization of high torque and low pulsation. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a high-performance drive axially yokeless segmented stator flux switching permanent magnet motor provided by the present invention.

[0020] Figure 2 This is a schematic diagram of the magnetic circuit path.

[0021] Figure 3 This is a schematic diagram of the armature winding.

[0022] Figure 4 This is a waveform diagram of the back electromotive force.

[0023] Figure 5 This is a torque waveform diagram.

[0024] In the diagram: 1-Rotor; 2-Stator; 3-Modular stator unit; 4-Permanent magnet; 5-Iron core; 6-Armature winding. Detailed Implementation

[0025] The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

[0026] like Figure 1 As shown, a high-performance drive axial yokeless segmented stator flux switching permanent magnet motor adopts an axial dual rotor-single stator structure. The rotor 1 is arranged parallel and coaxially on both sides of the stator 2. The stator 2 is composed of multiple separate modular stator units 3. There is no stator yoke connection between the modular stator units 3. The modular stator unit 3 includes a tangentially magnetized permanent magnet 4 and two iron cores 5 that clamp the permanent magnet 4. An armature winding 6 is wound around the outside of the iron core 5.

[0027] The two rotor teeth are offset by half a pole pitch angle, forming two parallel planar air gaps with the stator 2.

[0028] The rotor 1 has a salient pole structure with 22 teeth, and forms a magnetic field modulation relationship with the modular stator unit 3.

[0029] The modular stator unit 3 has 12 units.

[0030] like Figure 3 As shown, armature winding 6 adopts a fractional-slot concentrated winding with 4 pole pairs. By optimizing the coil arrangement, the number of copper wires at the ends is reduced, copper losses are decreased, and the axial magnetic flux path is adapted.

[0031] Because the stator module has no yoke, magnetic flux cannot propagate directly between adjacent modules; a closed magnetic circuit must be formed through the coordination of two rotors. For example... Figure 2 As shown, the magnetic circuit path is: permanent magnet → iron core → upper air gap → upper rotor → upper air gap → iron core → another permanent magnet → iron core → lower air gap → lower rotor → lower air gap → iron core → the original permanent magnet, forming a symmetrical ring loop on both sides.

[0032] When rotor 1 rotates, the change in the relative position of the rotor teeth and the modular stator unit 3 causes a periodic change in magnetic reluctance, resulting in an alternating air gap magnetic flux density, which in turn induces a back electromotive force in the armature winding 6. The dual-rotor design creates upper and lower air gap magnetic field coupling, enhancing the magnetic flux modulation effect.

[0033] The method of magnetic field modulation is to add the constraint m·k≠1 to the following formula to adapt to the yokeless axial structure:

[0034] p r =mp a ±kp m (m = 1, 5, 7..., k = 1, 3, 5...)

[0035] In the formula, m and k are both parameter coefficients; p r p is the number of rotor teeth. a p is the number of pole pairs in the armature winding. m is the number of pole pairs of the permanent magnet.

[0036] Let m = 1, k = 3, corresponding to the number of rotor teeth p r =22, number of winding pole pairs p a =4, number of permanent magnet pole pairs p m =6.

[0037] The rotor offset angle is designed as shown in the following formula.

[0038] α=γ / 2

[0039] In the formula, α is the offset angle of the dual rotors, and γ is the rotor pole pitch. Optimizing magnetic circuit coupling reduces motor torque ripple.

[0040] like Figure 4 As shown, the no-load back EMF total harmonic distortion (THD) is 4.3%, the waveform has high sinusoidal characteristics, and the motor performance is good.

[0041] like Figure 5 As shown, the average steady-state torque reaches 22.2 Nm, while the torque ripple is only 6.2%, and the cogging torque does not exceed 0.6 Nm. The motor has excellent performance and meets the requirements of a high-performance drive motor.

[0042] The above specific embodiments are used to explain and illustrate the present invention, and are only preferred embodiments of the present invention, not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made to the present invention within the spirit and scope of the claims shall fall within the protection scope of the present invention.

Claims

1. A high-performance permanent magnet motor with a segmented stator flux switching design for axial drive without a yoke, characterized in that: An axial dual-rotor-single-stator structure is adopted. The rotor (1) is arranged parallel and coaxially on both sides of the stator (2). The stator (2) is composed of multiple separate modular stator units (3). There is no stator yoke connection between the modular stator units (3). The modular stator unit (3) includes a tangentially magnetized permanent magnet (4) and two iron cores (5) that clamp the permanent magnet (4). An armature winding (6) is wound around the outside of the iron core (5).

2. The high-performance drive axial yokeless segmented stator flux-switching permanent magnet motor according to claim 1, characterized in that: The two rotors (1) have their teeth circumferentially offset by half a pole pitch angle, forming two parallel planar air gaps with the stator (2).

3. The high-performance drive axial yokeless segmented stator flux-switching permanent magnet motor according to claim 1, characterized in that: The rotor (1) has a salient pole structure with 22 teeth, and forms a magnetic field modulation relationship with the modular stator unit (3).

4. The high-performance drive axial yokeless segmented stator flux-switching permanent magnet motor according to claim 1, characterized in that: The modular stator unit (3) has 12 units.

5. The high-performance drive axial yokeless segmented stator flux-switching permanent magnet motor according to claim 1, characterized in that: The armature winding (6) adopts a fractional slot concentrated winding with a winding pole pair number of 4.

6. The high-performance drive axial yokeless segmented stator flux-switching permanent magnet motor according to claim 1, characterized in that: The magnetic circuit path of a permanent magnet motor is as follows: permanent magnet → iron core → upper air gap → upper rotor → upper air gap → iron core → another permanent magnet → iron core → lower air gap → lower rotor → lower air gap → iron core → the original permanent magnet, forming a symmetrical loop on both sides.

7. The high-performance drive axial yokeless segmented stator flux-switching permanent magnet motor according to claim 1, characterized in that: The method for modulating the magnetic field of a permanent magnet motor is to add the constraint m·k≠1 to the following formula to adapt to the yokeless axial structure: p r =mp a ±kp m (m=1,5,7..,k=1,3,5..) In the formula, m and k are both parameter coefficients; p r p is the number of rotor teeth. a p is the number of pole pairs in the armature winding. m is the number of pole pairs of the permanent magnet.

8. The high-performance drive axial yokeless segmented stator flux-switching permanent magnet motor according to claim 1, characterized in that: The rotor offset angle of a permanent magnet motor is designed as shown in the following formula. α=γ / 2 In the formula, α is the offset angle of the dual rotors, and γ is the rotor pole pitch. Optimizing magnetic circuit coupling reduces motor torque ripple.

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