An axial magnetic concentration segmented stator permanent magnet motor based on non-uniform Halbach

Abstract

A segmented stator permanent magnet motor based on non-uniform Halbach magnetization includes a modular segmented stator, a composite salient pole rotor, and non-uniform radial axial Halbach permanent magnets. The rotor is coaxially disposed inside the stator. The non-uniform radial axial Halbach permanent magnets disposed on the modular segmented stator include axially magnetized permanent magnets and tangentially magnetized permanent magnets. The modular segmented stator includes armature coils, multiple segmented stator modules arranged parallel along the axial direction, and segmented stator gaps disposed between adjacent segmented stator modules. Each segmented stator module includes stator teeth and a stator yoke. Each segmented stator module is sequentially offset tangentially around the outer circle of the stator by one stator tooth angle along the axial direction. In summary, this invention overcomes the shortcomings of the prior art, has a reasonable design, and axially segments the stator and applies axially magnetized permanent magnets of unequal lengths within the segment gaps. These permanent magnets, together with the non-circumferentially excitation permanent magnets, form a non-uniform Halbach arrangement to achieve magnetization characteristics, and have high application prospects.

Description

Technical Field

[0001] This invention relates to the field of stator permanent magnet motor technology, and in particular to an axially focused segmented stator permanent magnet motor based on non-uniform Halbach. Background Technology

[0002] With the development of the motor industry, permanent magnet motors are widely used in industrial and transportation fields due to their advantages such as high efficiency, high power density, and high reliability. To achieve high torque output at lower transmission speeds, permanent magnet synchronous motors are often cascaded with gear reducers as the main power source in industry. However, the introduction of mechanical gearboxes makes the power system prone to problems such as mechanical losses, transmission efficiency, and noise. To solve this problem, researchers have combined electromagnetic gears with motors to obtain a magnetic field modulation motor structure.

[0003] Magnetic field modulation motors are generally classified into rotor permanent magnet magnetic field modulation motors and stator permanent magnet magnetic field modulation motors according to the position of the permanent magnets. Stator permanent magnet magnetic field modulation motors utilize stator permanent magnets for excitation, and the rotor is made of stacked silicon steel sheets, resulting in a simple structure and high reliability. The armature magnetic field and permanent magnet magnetic field are coupled in the air gap after being modulated by modulation poles to achieve high torque density. However, traditional stator permanent magnet magnetic field modulation motors use single-sided excitation and suffer from severe magnetic leakage, limiting further improvements in torque density. Therefore, directional enhancement of the air gap magnetic field has become a research hotspot in the field of stator permanent magnet magnetic field modulation motors.

[0004] Chinese patent application CN202410653426.0 discloses an intermittent trapezoidal distributed Halbach permanent magnet array that optimizes the air gap magnetic field distribution by adjusting the spacing between the permanent magnet poles and the iron core, reducing high-order harmonics in the air gap magnetic flux density, and increasing output torque, thereby reducing torque ripple. It also involves embedding the Halbach permanent magnet array between the stator split teeth, combined with a DC excitation winding to form a hybrid excitation and magnetic field adjustment mechanism. The static magnetic field generated by the DC excitation winding, after being modulated by the rotor salient poles, interacts with armature harmonics to achieve flexible magnetic field adjustment. Chinese patent application CN201410602830.1 proposes a convex block Halbach permanent magnet array that, while retaining the traditional Halbach permanent magnet array arrangement, optimizes the permanent magnet shape to conform to sinusoidal distribution characteristics, enhancing the air gap magnetic field while weakening unwanted harmonics. While these methods effectively achieve magnetic concentration and optimize the amplitude or composition of air gap harmonics, they do not consider the influence of leakage flux at the armature winding ends or the performance degradation caused by winding temperature rise. To address the above issues, we now provide an axially focused segmented stator permanent magnet motor based on non-uniform Halbach magnetization. Summary of the Invention

[0005] To address the problems mentioned in the background section, this invention provides an axially focused segmented stator permanent magnet motor based on non-uniform Halbach magnetization.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A segmented stator permanent magnet motor based on non-uniform Halbach magnets includes a modular segmented stator, a composite salient pole rotor, and a non-uniform radial-axial Halbach permanent magnet. The composite salient pole rotor is coaxially disposed inside the modular segmented stator, and the non-uniform radial-axial Halbach permanent magnet is disposed on the modular segmented stator. The non-uniform radial-axial Halbach permanent magnet includes an axially magnetized permanent magnet and a tangentially magnetized permanent magnet.

[0008] The modular segmented stator includes an armature coil, multiple segmented stator modules arranged in parallel along the axial direction, and segmented stator gaps disposed along the axial direction between adjacent segmented stator modules. Each segmented stator module includes stator teeth and a stator yoke. Each segmented stator module is tangentially offset by one stator tooth angle along the axial direction around the outer circle of the stator. The permanent magnets in two adjacent segmented stator modules constitute non-uniform radial-axial Halbach permanent magnets with opposite polarities. The segmented stator gaps are disposed between adjacent segmented stator modules and also function as cooling channels to reduce the temperature rise of local hot spots.

[0009] The composite salient pole rotor includes a rotor yoke, a shaft, radial rotor salient poles, and end salient pole rotors located at both ends of the axial direction. The end salient pole rotors are configured to couple the magnetic field excited by the axially magnetized permanent magnet with the armature magnetic field at the end of the armature coil to generate torque, while being fan-shaped to disturb the air inside the motor for ventilation and cooling.

[0010] Furthermore, the axially magnetized permanent magnet is applied along the axial direction to the segmented stator gap and is axially equal to the segmented stator gap. The tangentially magnetized permanent magnet is applied along the circumferential direction to the middle of the stator teeth between adjacent segmented stator modules. They are combined in the axial direction to form a three-segment Halbach magnetic array and in the radial direction to form a four-directional Halbach magnetic array.

[0011] Furthermore, the gap length of the segmented stator gap exhibits a non-linear variation that decreases from the axial center towards both ends.

[0012] Furthermore, the end salient pole rotor, together with the modular segmented stator and the gap between the composite salient pole rotor and the segmented stator, constitute a ventilation and cooling channel, forming a magnetothermal coupling reuse structure.

[0013] Furthermore, the outer diameter of the axially magnetized permanent magnet is smaller than the outer diameter of the modular segmented stator, the inner diameter of the axially magnetized permanent magnet is larger than the inner diameter of the stator yoke, and there is a gap between adjacent axially magnetized permanent magnets, which together with the gap on the outer surface of the axially magnetized permanent magnet constitute a hidden cooling channel.

[0014] Compared with the prior art, the beneficial effects of the present invention are:

[0015] 1. This invention divides the stator core into axial segments and applies axially magnetized permanent magnets of varying lengths within the segment intervals. These permanent magnets, together with non-circumferentially axially excitation permanent magnets, form a non-uniform Halbach arrangement to obtain magnetic focusing characteristics, enhance air gap harmonics, and increase the torque density of the motor. Furthermore, this invention extends the salient pole rotor teeth axially to a portion higher than the end coils and then radially to the outer circle of the stator core. The resulting end salient pole rotor utilizes the axial magnetic field and end coils to generate torque, fully utilizing end leakage flux and increasing output power.

[0016] 2. The magnetothermal coupling multiplexing structure formed by the end salient pole rotor enables internal forced ventilation cooling that adapts to the rotational speed. Combined with the non-uniform segmented stator gap and permanent magnet flow channel, an efficient axial cooling path is constructed, improving the reliability and lifespan of the motor during long-term operation.

[0017] 3. The rotor is a pure silicon steel sheet laminated structure, without permanent magnets or windings, resulting in high mechanical strength and suitability for high-speed operation. This design improves performance without introducing a complex additional cooling system, achieving a balance between high power density and good cost-effectiveness.

[0018] In summary, this invention overcomes the shortcomings of the prior art and has a reasonable design. It divides the stator into axial segments and applies axially magnetized permanent magnets of unequal lengths within the segment intervals. These permanent magnets, together with non-circularly axially excitation permanent magnets, form a non-uniform Halbach arrangement to obtain magnetic focusing characteristics, which has high social value and application prospects. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the axial cross-sectional structure of a motor according to an embodiment of the present invention.

[0021] Figure 2 This is a schematic diagram of the radial structure of a motor according to an embodiment of the present invention.

[0022] Figure 3 This is a three-dimensional exploded view of a rotor according to an embodiment of the present invention.

[0023] Figure 4 This is a comparison diagram of the output torque of the motor of this invention and a traditional flux-switching motor.

[0024] Figure 5 This is the temperature rise diagram of the motor stator of the present invention.

[0025] Figure 6 This is a temperature rise diagram of the stator of a traditional flux-switching motor.

[0026] Figure 7 This is a temperature rise diagram of the armature winding of the motor of the present invention.

[0027] Figure 8 This is a temperature rise diagram of the armature winding of a traditional flux-switching motor.

[0028] In the figure: Modular segmented stator 1, composite salient pole rotor 2, non-uniform radial-axial Halbach permanent magnet 3, armature coil 101, segmented stator module 102, segmented stator gap 103, stator teeth 1021, stator yoke 1022, axially magnetized permanent magnet 301, tangentially magnetized permanent magnet 302, rotor yoke 201, shaft 202, radial rotor salient pole 203, end salient pole rotor 204. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] In order to achieve high-quality torque output from the stator permanent magnet synchronous motor, this invention discloses a segmented stator permanent magnet motor based on axial non-uniform Halbach, based on the exploration of new stator permanent magnet synchronous motors and motor air gap harmonic suppression technologies.

[0031] Example 1

[0032] refer to Figure 1-8 As shown, a segmented stator permanent magnet motor based on axial non-uniform Halbach magnets includes a modular segmented stator 1, a composite salient pole rotor 2, and non-uniform radial-axial Halbach permanent magnets 3.

[0033] The modular segmented stator 1 includes an armature coil 101, segmented stator modules 102, and segmented stator gaps 103. Each segmented stator module 102 includes stator teeth 1021 and a stator yoke 1022. The armature coil 101 is wound on the stator teeth 1021. Each segmented stator module 102 is arranged parallel to the axial direction and is tangentially offset by one stator tooth angle around the outer circle of the stator. This staggered arrangement enhances the modulation effect of the magnetic field. The permanent magnets within adjacent segmented stator modules 102 form non-uniform radial-axial Halbach permanent magnets 3 with opposite polarities. The segmented stator gaps 103 are axially positioned between adjacent segmented stator modules 102, serving as cooling channels to reduce local hot spot temperature rise. The length of the segmented stator gaps 103 is mapped to the surface heat dissipation coefficient of the iron core under the motor's design conditions, and exhibits a non-linear decreasing change from the axial center towards both ends.

[0034] The gap length of the segmented stator gap 103 δ The nonlinear variation decreases from the axial center towards both ends, satisfying...

[0035]

[0036] in, L The axial stacking length of the motor is used as the effective axial length. For axial coordinates, the origin is taken as the axial center of the motor; the range is [ −L / 2, L / 2], δ c The clearance length at the axial center of the motor is taken as the maximum value. δ end The minimum value is the clearance length at the axial end of the motor. p and q The distribution coefficient is obtained through simulation of temperature distribution.

[0037] The non-uniform radial-axial Halbach permanent magnet 3 includes an axially magnetized permanent magnet 301 and a tangentially magnetized permanent magnet 302. The axially magnetized permanent magnet 301 is applied axially at the segmented stator gap 103 and is axially equal in length to the segmented stator gap 103, with its magnetization direction along the motor axis. The tangentially magnetized permanent magnet 302 is embedded inside the stator teeth 1021, with its magnetization direction along the stator tangential direction. By carefully designing the size, position, and magnetization direction of these permanent magnets, they are combined axially to form a three-segment Halbach magnetic array and radially to form a four-directional Halbach magnetic array, making the magnetic field act more concentrated on the air gap and significantly improving the utilization efficiency of the magnetic field.

[0038] The composite salient pole rotor 2 includes a rotor yoke 201, a shaft 202, radial rotor salient poles 203, and end salient pole rotors 204. The composite salient pole rotor 2 is supported by the shaft 202, and its main body is composed of radial rotor salient poles 203 and rotor yoke 201. The end salient pole rotors 204 are located at both ends of the composite salient pole rotor 2 along the axial direction. The end salient pole rotors 204 couple the magnetic field excited by the axially magnetized permanent magnet 301 and the armature magnetic field at the end of the armature coil 101 to generate torque. The end salient pole rotors 204 are fan-shaped, disturbing the air inside the motor through the flow channel formed by the gap between the modular segmented stator 1 and the composite salient pole rotor 2 and the segmented stator gap 103, providing forced ventilation cooling to the motor ends, reducing the temperature rise of local hot spots, and forming a magnetothermal coupling multiplexing structure that can complete electromagnetic energy conversion and end ventilation cooling.

[0039] The outer diameter of the axially magnetized permanent magnet 301 is smaller than the outer diameter of the modular segmented stator 1, and its inner diameter is larger than the inner diameter of the stator yoke 1022. There is a gap between adjacent axially magnetized permanent magnets 301, which together with the gap on the outer surface of the axially magnetized permanent magnet 301 form a hidden flow channel, thereby improving the heat dissipation area and cooling effect.

[0040] Working Principle: After three-phase alternating current is applied to the armature coil 101, a rotating armature magnetic field is generated. Simultaneously, a strong static permanent magnet magnetic field is established on the stator side by a non-uniform radial Halbach permanent magnet 3. The characteristics of this permanent magnet magnetic field are as follows: the non-uniform radial Halbach permanent magnet 3 is formed by axially segmented permanent magnets 301 and tangentially magnetized permanent magnets 302. This array forms a three-segmented magnetic field in the axial direction and a four-directional magnetic focusing effect in the radial direction, which directionally enhances the fundamental amplitude of the air gap magnetic field and optimizes the harmonic components. When the composite salient pole rotor 2 rotates, its radial rotor salient pole 203 acts as a modulation pole, continuously modulating the permanent magnet magnetic field and armature magnetic field on the stator side. The modulated permanent magnet magnetic field harmonics and the armature magnetic field harmonics have the same number of pole pairs and rotate synchronously, thus interacting to generate stable reluctance torque and permanent magnet torque, achieving high-efficiency electromechanical energy conversion. The segmented stator module 102 is tangentially offset along the axial direction, which further optimizes the modulation effect of the magnetic field and helps to reduce torque ripple.

[0041] The composite salient-pole rotor 2's shaft 202 extends radially beyond the end coils to the outer circumference of the stator core, forming an end-salient-pole rotor 204 that generates torque using the axial magnetic field and end coils, fully utilizing end leakage flux and increasing output power. Specifically, the end windings of conventional motors generate significant end leakage flux, which is typically wasted as it doesn't contribute to torque generation. In this invention, the end-salient-pole rotor 204, located at both ends of the rotor, extends into the end winding region. It simultaneously cuts two magnetic fields: one is the axial magnetic field established in the motor end region by the axially magnetized permanent magnet 301, and the other is the end leakage flux magnetic field generated by the armature coils 101. The end-salient-pole rotor 204 interacts with these two magnetic fields, generating additional end axial torque. This design converts harmful leakage flux into useful torque, significantly improving the motor's torque density and material utilization.

[0042] The end-salient pole rotor 204 is designed in a fan-blade shape, which is the magnetothermal coupling multiplexing structure of this invention. This disturbs the air inside the motor, allowing it to flow through a channel formed by the stator-rotor air gap and segmented stator gaps, reducing the temperature rise of local hot spots. The airflow ultimately provides efficient cooling to the stator core, armature windings, and permanent magnets, which have the highest temperatures. The cooling intensity automatically adjusts with the rotational speed (load): the higher the rotational speed, the greater the heat generation, and the stronger the fan-blade effect, the greater the cooling airflow, thus achieving adaptive thermal management.

[0043] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

[0044] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0045] In this invention, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," "link," and "fix" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, a direct connection, or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0046] The control method of this invention is automatic control through a controller. The control circuit of the controller can be implemented by simple programming by those skilled in the art. The power supply is also common knowledge in the field. Furthermore, since this invention is mainly used to protect mechanical devices, the control method and circuit connection will not be explained in detail here.

[0047] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. An axially focused segmented stator permanent magnet motor based on non-uniform Halbach magnetization, characterized in that, include The modular segmented stator (1), the composite salient pole rotor (2), and the non-uniform radial axial Halbach permanent magnet (3) are arranged coaxially inside the stator (1). The non-uniform radial axial Halbach permanent magnet (3) is arranged on the modular segmented stator (1). The non-uniform radial axial Halbach permanent magnet (3) includes an axially magnetized permanent magnet (301) and a tangentially magnetized permanent magnet (302). The modular segmented stator (1) includes an armature coil (101), multiple segmented stator modules (102) arranged in parallel along the axial direction, and segmented stator gaps (103) arranged along the axial direction between adjacent segmented stator modules (102); each segmented stator module (102) includes stator teeth (1021) and stator yokes (1022); each segmented stator module (102) is tangentially offset by one stator tooth angle along the axial direction around the outer circle of the stator; the permanent magnets in two adjacent segmented stator modules (102) constitute non-uniform radial-axial Halbach permanent magnets (3) with opposite polarities; the segmented stator gaps (103) are arranged between adjacent segmented stator modules (102) and also serve as cooling channels to reduce the temperature rise of local hot spots; The composite salient pole rotor (2) includes a rotor yoke (201), a shaft (202), a radial rotor salient pole (203), and end salient pole rotors (204) located at both ends of the shaft (202); the end salient pole rotors (204) are configured to couple the magnetic field excited by the axially magnetized permanent magnet (301) and the armature magnetic field at the end of the armature coil (101) to generate torque, while being fan-shaped to disturb the air inside the motor for ventilation and cooling; The axially magnetized permanent magnet (301) is applied axially to the segmented stator gap (103) and is axially equal in length to the segmented stator gap (103). The tangentially magnetized permanent magnet (302) is applied circumferentially to the middle of the stator teeth (1021) between adjacent segmented stator modules (102). The permanent magnets are combined axially to form a three-segment Halbach magnetic array and radially to form a four-directional Halbach magnetic array. The gap length of the segmented stator gap (103) δ The nonlinear variation decreases from the axial center towards both ends, satisfying... ； in, L The axial stacking length of the motor, For axial coordinates, the origin is taken as the axial center of the motor; the range is [ −L / 2, L / 2], δ c This is the clearance length at the axial center of the motor. δ end This refers to the clearance length at the axial end of the motor. p and q The distribution coefficient is obtained through simulation of temperature distribution.

2. The axially focused segmented stator permanent magnet motor based on non-uniform Halbach as described in claim 1, characterized in that: The end salient pole rotor (204), together with the air gap between the modular segmented stator (1) and the composite salient pole rotor (2) and the segmented stator gap (103), form a ventilation and cooling channel, thus forming a magnetothermal coupling reuse structure.

3. The axially focused segmented stator permanent magnet motor based on non-uniform Halbach as described in claim 1, characterized in that: The outer diameter of the axially magnetized permanent magnet (301) is smaller than the outer diameter of the modular segmented stator (1), the inner diameter of the axially magnetized permanent magnet (301) is larger than the inner diameter of the stator yoke (1022), and there is a gap between adjacent axially magnetized permanent magnets (301), which together with the gap on the outer surface of the axially magnetized permanent magnet (301) form a hidden cooling channel.

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