Heat collection type high overload capacity permanent magnet motor based on polygonal dissipation groove iron yoke

Abstract

The heat collection type high-overload-capacity permanent magnet motor is composed of a permanent magnet inner rotor and a heat collection type stator, polygonal dissipation grooves with acute angle characteristics are applied to the positions, right facing the centers of stator grooves, of the stator iron yokes, and through the matching design of the harmonic wave wavelength and the groove distance between the dissipation grooves, the heat collection type high-overload-capacity permanent magnet motor is formed. And the target asynchronous rotating harmonic waves are guided to be dissipated at the acute-angle slot tip in the forms of eddy-current loss and magnetic hysteresis loss, so that a heat source in the motor is forced to be enriched in a dissipation slot, an iron yoke heat collection structure is formed, and temperature rise distribution in the motor is reconstructed. Under the overload working condition, the ring position where the highest temperature rise and heat accumulation radial distribution of the motor are located is concentrated at the acute-angle groove tip, heat dissipation components such as heat conduction ceramic are added in the dissipation groove, and the problem that the torque output capacity is limited under the overload working condition of the motor is solved. The motor has high overload capacity and is suitable for high-torque-density application occasions such as robot joints and electric vehicle driving.

Description

TECHNICAL FIELD

[0001] The application relates to the field of permanent magnet motors, in particular to a heat collection type high overload capacity permanent magnet motor based on a polygonal dissipation slot yoke, and belongs to the technical field of motor design, efficiency optimization method and heat management. BACKGROUND

[0002] Taking an electric vehicle as an example, the driving motor needs to keep high efficiency operation under the rated working condition, and has a short-time overload capacity of 150%-200% under transient working conditions such as climbing and sudden acceleration. Similar requirements also exist in high-end application scenarios such as industrial robot servo systems and aerospace actuation systems. Permanent magnet synchronous motors (PMSM) have become the preferred solution due to their advantages such as efficiency and power density, but their overload performance is facing a fundamental bottleneck: when the PMSM works in a 150% overload working condition, the temperature rise rate can reach 3-5 times that of the rated working condition, and the local hot spot temperature exceeding 180℃ will cause irreversible demagnetization of the permanent magnet, which seriously restricts the system reliability. The essence of this problem lies in the fact that the "uniform magnetic circuit design" and "distributed heat dissipation architecture" of the traditional motor are difficult to match the nonlinear thermal-magnetic coupling requirements under high overload working conditions.

[0003] The current mainstream solutions have three technical shackles: first, in terms of magnetic circuit design, the traditional stator adopts homogeneous silicon steel sheet lamination, and the saturation magnetic flux density is uniform, which leads to disordered fluctuations of the stator tooth magnetic flux density under high armature reaction, causing local magnetic saturation and dramatic increase of eddy current loss. Secondly, in terms of heat management, existing technologies such as stator shell water cooling or rotor shaft oil cooling can reduce the average temperature rise, but the local hot spot of micron scale cannot be effectively cooled. More importantly, the traditional design considers the magnetic saturation characteristics and the heat dissipation path separately, for example, by adding permanent magnets to adjust the magnetic field in the slot, but it does not solve the additional eddy current heating problem caused thereby, forming a "magnetic-thermal contradiction". SUMMARY

[0004] The purpose of the present application is to provide a heat collection type high overload capacity permanent magnet motor based on a polygonal dissipation slot yoke, which solves the problem of local hot spots caused by the accumulation of non-synchronous rotating harmonics in the motor by combining the harmonic migration mechanism and the structure heat collection design.

[0005] The present application provides a heat collection type high overload capacity permanent magnet motor based on a polygonal dissipation slot yoke, which comprises: a rotor and a stator, wherein the stator comprises stator teeth, armature coils and a stator yoke; The stator yoke is provided with a plurality of polygonal dissipation grooves, and acute-angle groove tips are formed in the polygonal dissipation grooves; through matching arrangement of a target non-synchronous rotating harmonic wavelength and a slot pitch between adjacent polygonal dissipation grooves, the electric field enhancement effect, the forced bending of the eddy current path and the distortion of the magnetic force line at the acute-angle groove tips can be caused, so that the target non-synchronous rotating harmonic is guided to dissipate in the form of eddy current loss and magnetic hysteresis loss at the acute-angle groove tips, the heat source in the motor is forced to be enriched in the polygonal dissipation grooves, the heat is accumulated at the polygonal dissipation grooves, the temperature rise distribution in the motor is restructured, the active heat dissipation component is applied, and the "harmonic migration polygonal dissipation groove heat collection active heat dissipation" mechanism is formed.

[0006] Optionally, the polygonal dissipation groove is an equilateral triangle, a rhombus or an irregular polygon.

[0007] Optionally, the angle of the acute-angle groove tip is less than 60°, so as to enhance the electric field concentration effect and the target non-synchronous rotating harmonic guiding capability.

[0008] Optionally, the polygonal dissipation groove is arranged in the middle region between the stator yoke and the stator tooth in the radial direction, so as to realize effective heat aggregation in the radial direction.

[0009] Optionally, the polygonal dissipation groove is filled with heat-conducting ceramic, graphite heat dissipation sheet or high-thermal-conductivity insulating resin material, so as to form a heat-electricity-magnetism coupling active heat dissipation channel from the tip to the shell, and heat conduction efficiency is improved.

[0010] Optionally, the polygonal dissipation grooves are equidistantly arranged in the circumferential direction.

[0011] Optionally, the slot pitch between adjacent polygonal dissipation grooves is an odd multiple of the half wavelength of the target non-synchronous rotating harmonic, so as to realize directional dissipation of the target non-synchronous rotating harmonic.

[0012] Optionally, the stator yoke is formed in a lamination manner, and the polygonal dissipation grooves are arranged in each layer of the lamination, and the polygonal dissipation grooves are arranged in a staggered manner between layers, so as to expand the heat source migration path and enhance the three-dimensional heat dissipation performance.

[0013] Compared with the prior art, the present application has the following beneficial effects: 1. The application proposes a structure of a magnetic saturation induction core: a polygonal dissipation slot with an acute slot tip is formed in the center of the stator yoke, and the target non-synchronous rotating harmonic wavelength is matched and arranged between the slot spacing of adjacent polygonal dissipation slots, realizing the directional capture and dissipation of non-synchronous rotating harmonics. Through the mechanisms of electric field enhancement effect, forced bending of eddy current path, and magnetic line distortion, the non-synchronous rotating harmonic wavelength is concentrated and dissipated in the form of eddy current loss and magnetic hysteresis loss at the acute slot tip, thereby effectively enriching the heat source in the dissipation slot area, constructing an active heat dissipation channel of "thermal-electric-magnetic coupling", realizing the spatial fixed control of the heat source, and specifically strengthening the weak heat dissipation area, so that the motor can still operate stably under short-time high load, and the torque output capacity is improved.

[0014] 2. The application has strong heat control ability. The application realizes the directional migration and active dissipation of harmonic loss through the dissipation slot structure, effectively avoids local overheating of the magnet edge or shaft end, and improves the thermal management efficiency.

[0015] 3. The application improves the overload capacity. The application specifically strengthens the weak heat dissipation area, so that the motor can still operate stably under short-time high load, and the torque output capacity is improved.

[0016] 4. The application has good structure adaptability. The application is applicable to internal rotor type and external rotor type motor topologies, and can be flexibly applied to various high torque density occasions, especially in compact space, variable load, and high cooling requirement scenes such as robots, electric vehicles, and industrial servo systems.

[0017] 5. The application considers both cost and performance. Compared with increasing the overall heat capacity, the application improves performance through local structure optimization, maintains simple structure while ensuring heat control performance improvement, reduces manufacturing and maintenance costs, and has higher cost performance. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 It is a structure diagram of a heat collecting type high overload capacity permanent magnet motor based on a polygonal dissipation slot yoke.

[0019] Figure 2 It is a stator structure diagram of a heat collecting type high overload capacity permanent magnet motor based on a polygonal dissipation slot yoke.

[0020] Figure 3 It is a structure diagram of a polygonal dissipation slot yoke.

[0021] Label explanation: 1. Rotor; 2. Stator.

[0022] 101. Rotor shaft; 102. Rotor core; 103. Rotor surface-mounted permanent magnet; 201. Stator tooth; 202. Armature coil; 203. Stator yoke; 204. Polygonal dissipation slot; 204-1. Acute slot tip. DETAILED DESCRIPTION

[0023] In the description of the present application, it needs to be understood that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, which are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements 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. In addition, the terms "first", "second" and the like are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined with "first", "second" and the like can explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise stated, the meaning of "a plurality of" is two or more. In the description of the present application, it needs to be explained that, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood through specific circumstances.

[0024] The present application will be further described below in conjunction with the drawings. The following examples are only used to more clearly illustrate the technical solutions of the present application, and cannot be used to limit the protection scope of the present application.

[0025] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application will be further described in detail below in conjunction with the drawings and examples.

[0026] In the prior art known to the inventors of the present application, due to the uncontrollable position of internal harmonic loss of the motor, the traditional permanent magnet motor often has local hot spot areas such as stator tooth ring, permanent magnet end face or shaft neck, resulting in local insulation aging, permanent magnet demagnetization, efficiency reduction and reliability reduction. Although the common water cooling, oil cooling or heat pipe structure can reduce the overall temperature in the macroscopic aspect, the targeted effect on the local hot spot area is limited, especially under the action of high frequency non-synchronous rotating harmonic, it is still easy to produce "hot spot" and cannot be quickly dispersed. In the working condition of strong armature reaction, high current density or existence of high order harmonic disturbance, it is easy to cause disordered distribution of magnetic saturation, dispersed heat source, and then cause problems such as rising of overall temperature rise, efficiency reduction, magnet demagnetization and the like.

[0027] The embodiment introduces a "polygonal dissipation slot" structure in the yoke of the stator to solve the above-mentioned hotspot and overload limitation problems, that is, a plurality of polygonal dissipation slots are opened along the surface of the yoke.

[0028] Specifically, as shown in the accompanying drawings, Figure 1 The embodiment provides a heat collecting type high overload capacity permanent magnet motor based on a polygonal dissipation slot yoke, which comprises a rotor 1 and a stator 2. The rotor 1 comprises a shaft 101, a rotor core 102 and rotor surface-mounted permanent magnets 103. The stator 2 comprises stator teeth 201, armature coils 202, a stator yoke 203 and polygonal dissipation slots 204.

[0029] The polygonal dissipation slots 204 are opened on the stator yoke 203, and the polygonal dissipation slots 204 form acute-angle slot tips 204-1. Through the matching design of the target non-synchronous rotating harmonic wavelength and the slot pitch of adjacent polygonal dissipation slots 204, the electric field enhancement effect, the forced bending of the eddy current path and the distortion of the magnetic force line at the acute-angle slot tips 204-1 can be caused, the non-synchronous rotating harmonic is guided to dissipate in the form of eddy current loss and magnetic hysteresis loss at the acute-angle slot tips 204-1, the heat source in the motor is forced to be enriched in the polygonal dissipation slots 204, the heat is accumulated at the polygonal dissipation slots 204, the temperature rise distribution in the motor is reconstructed and the active heat dissipation component is applied, and the "harmonic migration-polygonal dissipation slot heat collection-active heat dissipation" mechanism is formed.

[0030] The number, acute-angle and slot pitch between adjacent polygonal dissipation slots 204 of the acute-angle slot tips 204-1 in the polygonal dissipation slots 204 are determined by the migration harmonic wavelength and the magnetic flux density distribution.

[0031] The polygonal dissipation slots 204 are equilateral triangles, rhombuses or irregular polygons, and the acute-angle slot tips 204-1 have an angle less than 60°, which is used to enhance the electric field concentration effect and the non-synchronous rotating harmonic guiding capacity.

[0032] The polygonal dissipation slots 204 are arranged in the middle region between the stator yoke 203 and the stator teeth 201 in the radial direction to realize the effective aggregation of heat in the radial direction.

[0033] The stator yoke 203 is composed in a lamination manner, and the polygonal dissipation slots 204 are opened in each layer of the lamination, and the polygonal dissipation slots 204 are arranged in a staggered manner between layers to expand the heat source migration path and enhance the three-dimensional heat dissipation performance.

[0034] The angle of the acute corner slot tip 204-1 in the polygonal dissipation slot 204 is less than 60°; the polygonal dissipation slots 204 are arranged equidistantly along the circumference of the stator yoke 203, and the slot spacing between adjacent polygonal dissipation slots 204 is an odd multiple of the half wavelength of the target asynchronous rotating harmonic, so as to ensure that the magnetic fields between adjacent slots are opposite, and the maximum gradient is formed at the tip, which makes the electric field concentration area formed at the acute corner slot tip 204-1, and through the Faraday's law of electromagnetic induction and the Lenz's law, the varying magnetic flux generates a locally enhanced induced potential at the acute corner slot tip 204-1, thereby inducing a higher amplitude eddy current loop. At the same time, the magnetic lines of force are sharply bent at the position of the acute corner slot tip 204-1, changing the original magnetic flux path, so that the eddy current path is forced to bend and concentrate in the acute corner slot tip 204-1 area. Since the eddy current loss and the hysteresis loss depend on the electric field strength, the magnetic flux change rate and the material resistance, these sharp corner areas instantaneously generate higher density electromagnetic loss, thereby efficiently converting harmonic energy into local heat energy, realizing the directional capture and concentrated dissipation of harmonics.

[0035] This structural mechanism is similar to an "energy trap", so that the asynchronous harmonic energy is concentrated and accumulated as a heat source in the acute corner slot tip 204-1 area of the polygonal dissipation slot 204, rather than spreading to the winding or magnet blind area. At the same time, the polygonal dissipation slot 204 is filled with high-thermal-conductivity insulating material, and a micro-heat-pipe or PTC temperature control module is integrated, forming a heat-electricity-magnetic coupling active heat dissipation channel from the tip to the shell. These heat conduction paths are connected to the shell cooling system, which can quickly conduct the heat generated to the outside of the polygonal dissipation slot 204, avoiding local overheating.

[0036] The polygonal dissipation slots 204 are arranged equidistantly along the circumference of the stator yoke, and the multi-layer laminated stamping structure causes the slot bodies of the polygonal dissipation slots 204 to be arranged in a staggered manner in the axial direction, thereby forming a three-dimensional heat migration network, so that the heat diffusion path between the layers is more abundant. The geometric size, angle and position of the whole structure can be optimized through finite element electromagnetic-thermal simulation, so as to be matched with the main asynchronous harmonic mode in the motor. The structural level harmonic guiding and heat dispersion mechanism enables the motor to realize "controllable hot spot, controllable loss, and controllable heat", so as to ensure that the motor can still maintain stable temperature rise, continuously output high torque and have limited efficiency loss under high overload state.

[0037] In summary, the frequency matching between the target asynchronous rotating harmonic wavelength and the polygonal dissipation slot 204 design strengthens the "capture ability" of the structure to the harmonic, which becomes the main heat source area. The iron loss, including the hysteresis loss and the eddy current loss, and the copper loss are significantly improved, and the heat power density rapidly rises, so that this area becomes the heat accumulation core area.

[0038] Because the structure of the application clearly controls and guides the magnetic flux to the acute corner slot tip 204-1 area of the polygonal dissipation slot 204, and "locks" the heat source distribution position by matching the slot distance with the target non-synchronous rotating harmonic wavelength, the active heat dissipation structure can be arranged in the acute corner area of the polygonal dissipation slot 204, rather than trying to evenly distribute the heat source. Instead, the structure actively guides the harmonic heat to the most suitable location for heat dissipation. Such design realizes local heat collection and rapid heat conduction. The high-thermal-conductivity material in the polygonal dissipation slot 204 and the thermal control component can be directly configured at the tip position where the heat source is most concentrated, thereby forming a closed-loop channel from internal heat collection to external heat dissipation system. This effectively ensures that the motor remains stable in temperature rise under short-time high-load operation, and avoids triggering the over-temperature protection and the risk of permanent magnet demagnetization.

[0039] To effectively control the temperature rise in this area, a concentrated heat dissipation structure composed of high-thermal-conductivity material is arranged at the axial ends of the polygonal dissipation slot 204 of the stator yoke 203. This structure can adopt one or more of the following combinations: high-thermal-conductivity copper or aluminum end plate, embedded heat pipe channel, liquid cooling jacket ring channel, and high-thermal-conductivity interface material such as graphite gasket.

[0040] The thermal conductivity of the above-mentioned heat dissipation structure is preferably not less than 200 W / m·K, which significantly improves the motor's high-load running time and reliability.

[0041] The above is only the preferred embodiment of the application. It should be noted that for those skilled in the art, without departing from the technical principles of the application, several improvements and modifications can be made, which should also be considered within the scope of protection of the application.

Claims

1. A heat collecting type high overload capacity permanent magnet motor based on polygonal dissipating slot iron yoke, comprising: A rotor (1) and a stator (2), wherein the stator (2) comprises a stator tooth (201), an armature coil (202), and a stator yoke (203); The stator yoke (203) is characterized in that a plurality of polygonal dissipation grooves (204) are formed on the stator yoke (203), and acute-angle groove tips (204-1) are formed in the plurality of polygonal dissipation grooves (204); through matching arrangement of a target non-synchronous rotating harmonic wavelength and a slot pitch between adjacent polygonal dissipation grooves (204), an electric field enhancement effect, a forced bending of an eddy current path, and a magnetic force line distortion are caused at the acute-angle groove tips (204-1), so as to guide the target non-synchronous rotating harmonic to dissipate in the form of eddy current loss and magnetic hysteresis loss at the acute-angle groove tips (204-1), force heat sources in the motor to be enriched in the polygonal dissipation grooves (204), accumulate heat at the polygonal dissipation grooves (204), reconfigure a temperature rise distribution in the motor, and apply an active heat dissipation component, so as to form a "harmonic migration-polygonal dissipation groove heat collection-active heat dissipation" mechanism.

2. The permanent magnet electric machine of claim 1, wherein, The plurality of polygonal dissipation grooves (204) are equilateral triangles, rhombuses, or irregular polygons.

3. The permanent magnet electric machine of claim 1, wherein, The acute-angle groove tips (204-1) have an angle less than 60°, for enhancing an electric field concentration effect and a target non-synchronous rotating harmonic guiding capability.

4. The permanent magnet electric machine of claim 1, wherein, The plurality of polygonal dissipation grooves (204) are arranged in a middle region between the stator yoke (203) and the stator tooth (201) in a radial direction, so as to effectively accumulate heat in the radial direction.

5. The permanent magnet electric machine of claim 1, wherein, The plurality of polygonal dissipation grooves (204) are filled with heat-conductive ceramic, graphite heat dissipation sheets, or high-thermal-conductivity insulating resin materials, to form a heat-electricity-magnetism coupling active heat dissipation channel from a tip to a shell, for improving heat conduction efficiency.

6. The permanent magnet electric machine of claim 1, wherein, A slot pitch between adjacent polygonal dissipation grooves (204) is an odd multiple of a half wavelength of the target non-synchronous rotating harmonic, so as to realize directional dissipation of the target non-synchronous rotating harmonic.

7. The permanent magnet electric machine of claim 1, wherein, The stator yoke (203) is formed in a lamination manner, and each layer of punching sheet is provided with the plurality of polygonal dissipation grooves (204), and the plurality of polygonal dissipation grooves (204) are arranged in a staggered manner between layers, so as to expand a heat source migration path and enhance three-dimensional heat dissipation performance.

8. The permanent magnet electric machine of claim 1, wherein, The plurality of polygonal dissipation grooves (204) of the stator yoke (203) are provided with a concentrated heat dissipation structure formed of high-thermal-conductivity materials at both axial ends.

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