A stator multi-tooth axial flux permanent magnet motor with magnetic field modulation effect

Abstract

The present invention discloses a stator multi-tooth axial flux permanent magnet motor with a magnetic field modulation effect, which includes two axially symmetrically arranged rotors and a stator disposed between the two rotors; the stator includes a modular stator core and an armature winding, and each stator core module is provided with sector-shaped slots along the radial direction on the surface facing the air gap to form stator auxiliary teeth; the rotor includes a rotor core and sector-shaped permanent magnets, and the sector-shaped permanent magnets are fixed on the surface of the rotor core, and the two rotors on both sides are mirror-symmetric with respect to the stator. The stator multi-tooth axial flux permanent magnet motor with a magnetic field modulation effect of the present invention adopts an alternating pole double rotor and a modular single stator with auxiliary teeth. Without increasing the difficulty of winding the stator slots and sacrificing the slot fill factor, the stator auxiliary teeth can effectively modulate the air gap harmonic magnetic field to generate additional torque, and the modular stator can effectively reduce the weight and loss of the motor, further improving the motor efficiency and torque density.

Description

Technical Field

[0001] The present invention relates to the field of motor design, and specifically to a stator multi-tooth axial flux permanent magnet motor structure with a magnetic field modulation effect. Background Art

[0002] The axial flux permanent magnet motor has the advantages of compact structure, high torque density, and high efficiency. Its disc structure is convenient for adopting a multi-pole design to achieve low-speed and high-torque, and is particularly suitable for direct drive applications that require high power and have strict space and weight limitations, such as in-wheel motors, wind turbines, aircraft electric propulsion, etc.

[0003] For traditional axial flux permanent magnet motors, if a higher rotor pole number is adopted, the stator slot number also needs to be increased accordingly to enable the motor to obtain excellent torque performance. This may lead to too small stator slot sizes, making it difficult to insert the coil conductors and increasing the processing difficulty. On the other hand, the conductor slot fill factor in the stator slots is poor, resulting in an increase in winding resistance and losses, and reducing the operating performance of the motor. Summary of the Invention

[0004] Technical Problem: To solve the deficiencies mentioned in the above background, the purpose of the present invention is to provide a stator multi-tooth axial flux permanent magnet motor structure with a magnetic field modulation effect, which solves the problems such as difficult insertion of stator slots and low slot fill factor in the multi-pole design of low-speed and high-torque motors.

[0005] Technical Solution: The purpose of the present invention can be achieved by the following technical solutions:

[0006] A stator multi-tooth axial flux permanent magnet motor with a magnetic field modulation effect includes two axially symmetrically arranged rotors and a stator placed between the two rotors. The stator and the rotors are both annular structures and the stator and the rotors are coaxially connected;

[0007] The stator includes a stator core and an armature winding. The stator core is formed by circumferentially connecting independent stator core modules through a light non-magnetic material. On the surface of each stator core module facing the air gap, fan-shaped slots are radially opened to form stator auxiliary teeth. The armature winding coils are wound on the stator core modules, and the coil plane is parallel to the air gap plane;

[0008] The rotor includes a rotor core and fan-shaped permanent magnets. The fan-shaped permanent magnets are fixed on the surface of the rotor core. The two rotor structures have exactly the same dimensions and are mirror-symmetrical with respect to the stator disc;

[0009] Further, stator slots are formed between the modular stator cores. The stator slots are rectangular parallel slots, and the slot opening width is smaller than the slot body width. The number of stator core modules and the number of stator slots are both P s .

[0010] Further, the number t of slots on a single surface of each stator core module s and the number t of stator auxiliary teeth t satisfy t t = t s + 1, where P s is the number of stator core modules, and P s t t is the number of stator single - side auxiliary teeth.

[0011] Further, the rotor core is in an annular shape, and P r sector - shaped permanent magnets are evenly mounted along the circumference on the side facing the air gap. The magnetization directions of adjacent two permanent magnets are opposite and both are axial. P r is the number of single - rotor magnetic poles and is an even number.

[0012] Further, the number P of stator core modules s , the number P of single - rotor magnetic poles r , the number of pole pairs p of the armature winding ea and the number P s t t of stator single - side auxiliary teeth satisfy the following constraints:

[0013]

[0014] Further, the magnetization directions of the permanent magnets at the relative positions on the two rotor cores are the same.

[0015] Further, the armature winding can be either a double - layer concentrated winding (one coil is wound on each stator core module, and the number of coils is equal to P s ), or a single - layer concentrated winding (one coil is wound on every other stator core module, and the number of coils is equal to P s / 2).

[0016] Advantageous effects: A stator multi - tooth axial - flux permanent - magnet motor with a magnetic - field modulation effect according to the present invention adopts an alternating - pole double - rotor and a modular single - stator with auxiliary teeth. Without increasing the difficulty of winding in the stator slots and sacrificing the slot - filling rate, the stator auxiliary teeth can effectively modulate the air - gap harmonic magnetic field to generate additional torque, and the modular stator can effectively reduce the weight and loss of the motor, further improving the motor efficiency and torque density. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic structural diagram of a stator multi - tooth axial - flux permanent - magnet motor with a magnetic - field modulation effect according to the present invention;

[0018] Figure 2 is the stator core structure of a stator multi - tooth axial - flux permanent - magnet motor with a magnetic - field modulation effect according to the present invention;

[0019] Figure 3 is the rotor structure of the stator multi-tooth axial flux permanent magnet motor with magnetic field modulation effect of the present invention. Specific embodiments

[0020] The present invention will be further described below in conjunction with the embodiments and the accompanying drawings of the specification. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative work belong to the scope of protection of the present invention.

[0021] A stator multi-tooth axial flux permanent magnet motor with magnetic field modulation effect, as Figure 1 shown, includes two axially symmetrically arranged rotors and a stator placed between the two rotors. The stator and the rotors are both annular structures and the stator and the rotors are coaxially connected. The stator includes a stator core 1 and an armature winding 2. Fan-shaped slots 3 are radially formed on the surface of the stator core 1 facing the air gap to form stator auxiliary teeth 4. The armature winding 2 is composed of concentrated armature winding coils through series / parallel connection. The rotor includes a rotor core 5 and fan-shaped permanent magnets 6. The fan-shaped permanent magnets 6 are fixed on the surface of the rotor core 5. The structural dimensions of the two rotors on both sides are exactly the same and are mirror-symmetrical with respect to the stator disc.

[0022] Among them, the number of stator core modules P s , the number of poles of a single rotor P r , the number of pole pairs p of the armature winding ea , and the number of single-sided auxiliary teeth P s t t satisfy the following constraints:

[0023]

[0024] In this embodiment, P s = 12, P r = 34, p ea = 5, P s t t = 24.

[0025] As Figure 2As shown in the figure, the stator core 1 is composed of 12 mutually independent stator core modules, including the first stator core module 101, the second stator core module 102, …, and the twelfth stator core module 112. A sector-shaped slot 301 is formed on the first stator core module 101 to form two stator auxiliary teeth 401 and 402, a sector-shaped slot 302 is formed on the second stator core module 102 to form two stator auxiliary teeth 403 and 404, …, and a sector-shaped slot 312 is formed on the twelfth stator core module 112 to form two stator auxiliary teeth 423 and 424. The ratio of the width of the sector-shaped slot at the average radius of the stator to the width of the stator core module should be greater than 0.5 but not exceed 1 (designed to be 0.9 in this embodiment). A stator slot is formed between two adjacent stator core modules, and the stator slot is a rectangular parallel slot, and the width of the slot opening is less than the width of the slot body. The ratio of the width of the slot opening to the width of the slot body should be less than 0.5 (designed to be 0.2 in this embodiment).

[0026] The material of the stator core 1 can be selected from silicon steel or soft magnetic composite material. When laminated silicon steel is used, the lamination direction is the radial direction. The stator core module is supported and fixed by a lightweight and high-strength non-magnetic material, and the supporting components are usually processed and formed by using glass fiber FR4, ceramics, stainless steel, etc.

[0027] The armature winding 2 adopts a double-layer concentrated winding. The armature winding coils are wound on the stator core modules, and the number of coils is equal to the number of stator core modules. The coil plane is parallel to the air gap plane.

[0028] As Figure 3 shown in the figure, the rotor core 5 is circular ring-shaped, and 34 sector-shaped permanent magnets 6 are evenly mounted on the side facing the air gap along the circumference. The magnetization directions of two adjacent permanent magnets are opposite and both are axial. Among them, the magnetization directions of the permanent magnets at the relative positions on the two rotor cores 5 are the same.

[0029] Among them, the number of pole pairs of the rotor permanent magnet is 17, that is, a 17-pole permanent magnetic field is generated. The 24 stator auxiliary teeth modulate the 17-pole permanent magnetic field and will generate a 7 (24 - 17)-pole permanent magnetic field; in addition, the 24 stator auxiliary teeth modulate the 7-pole armature reaction magnetic field and will generate a 17 (24 - 7)-pole armature reaction magnetic field. Under the modulation of the stator auxiliary teeth, the 7-pole permanent magnetic field and the 7-pole armature reaction magnetic field rotate synchronously, and the 17-pole permanent magnetic field and the 17-pole armature reaction magnetic field rotate synchronously. The interaction of these two groups of harmonic magnetic fields can also generate an effective torque.

[0030] Compared with the same kind of traditional structure that also uses 12 stator core modules but without stator auxiliary teeth, in the embodiment of the present invention, due to the introduction of stator auxiliary teeth, the permanent magnet harmonic magnetic field and the armature reaction harmonic magnetic field with the same number of pole pairs can rotate synchronously, thus contributing to the effective torque, while the traditional structure can only rely on the fundamental magnetic field to generate torque or needs to increase the number of slots and poles to utilize the harmonic magnetic field. It can be seen that a stator multi-tooth axial flux permanent magnet motor with a magnetic field modulation effect according to the present invention can effectively improve the torque output capacity of the motor without increasing the difficulty of winding and sacrificing the slot fill factor.

[0031] The above are only the preferred embodiments of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several predictable improvements and equivalent replacements can be made. These technical solutions obtained by improving and equivalently replacing the claims of the present invention all fall within the protection scope of the present invention.

Claims

1. A stator multi-tooth axial flux permanent magnet motor with magnetic field modulation effect, comprising two axially symmetrically arranged rotors and a stator placed between the two rotors, characterized in that, The motor has a double air-gap structure; The stator includes a stator core (1) and an armature winding (2). The stator core (1) is formed by connecting independent stator core modules along the circumference through non-magnetic materials. Sector-shaped slots (3) are respectively formed on two surfaces of each stator core module facing the air gap to form stator auxiliary teeth (4). The armature winding (2) is formed by connecting concentrated armature winding coils in series / parallel. The armature winding coils are wound on the stator core modules, and the plane of the armature winding coils is parallel to the air-gap plane; The structural dimensions of the two rotor structures are exactly the same and are mirror-symmetric with respect to the stator; The number of stator core modules P s , the number of poles of a single rotor P r , the number of pole pairs p of the armature winding ea and the number of auxiliary teeth on one side of the stator core P s t t Satisfy the following constraints: t t The number of stator auxiliary teeth (4) on a single face of each stator core module.

2. The stator multi-tooth axial flux permanent magnet motor with magnetic field modulation effect according to claim 1, characterized in that, The number t of sector-shaped slots (3) on a single face of each stator core module s and the number t of stator auxiliary teeth (4) t satisfy t t = t s + 1. The number of stator auxiliary teeth (4) on a single face of the iron core (1) is P s t t , where P s is the number of stator core modules.

3. The stator multi-tooth axial flux permanent magnet motor with magnetic field modulation effect according to claim 1, characterized in that, Stator slots are formed between adjacent stator core modules. The stator slots are all rectangular parallel slots, and the width of the slot opening is smaller than the width of the slot body.

4. The stator multi-tooth axial flux permanent magnet motor with magnetic field modulation effect according to claim 1, characterized in that, The rotor includes a rotor core (5) and sector permanent magnets (6). The rotor core (5) is annular, and P sector permanent magnets (6) are evenly mounted along the circumference on the side facing the air gap. r The magnetization directions of two adjacent sector permanent magnets (6) are opposite and both are axial. P r is the number of single-rotor magnetic poles and is an even number.

5. The stator multi-tooth axial flux permanent magnet motor with magnetic field modulation effect according to claim 4, characterized in that, The magnetization directions of the sector-shaped permanent magnets (6) at corresponding positions on the two rotor cores (5) are the same.

6. The stator multi-tooth axial flux permanent magnet motor with magnetic field modulation effect according to claim 1, characterized in that, The armature winding is a double-layer concentrated winding or a single-layer concentrated winding.

Images