High-torque permanent magnet motor with active loss of high heat dissipation coefficient structure

Abstract

The invention discloses a high-torque permanent magnet motor with active loss of a high heat dissipation coefficient structure, which is composed of a permanent magnet rotor, a stator and an armature coil, an active loss ring is applied to the high heat dissipation coefficient part of the motor, and the capacity of nonsynchronous rotating harmonic waves for generating loss on the ring is enhanced by utilizing direct current magnetic regulation or a high-conductivity coefficient material; under the condition that the total loss of the motor is not increased, the loss in the motor is actively migrated to a high-heat-dissipation-coefficient part, and heat source distribution is reconstructed in a mode of increasing the loss of a high-heat-dissipation-coefficient structure. The loss of the low heat dissipation coefficient structure is reduced in a mode of actively increasing the magnetic adjustment copper loss or eddy current loss of the high heat dissipation coefficient structure, the maximum temperature rise and the temperature rise distribution distortion degree are reduced, and the problem that the torque lifting capability of the motor is limited due to the rise of the hot spot temperature is solved. The motor has the characteristics of high torque output capability and low maximum temperature rise, and is suitable for high torque density application occasions such as robot joints and electric vehicle driving.

Description

Technical Field

[0001] The present invention belongs to the field of motor design and manufacturing, and in particular relates to a high-torque permanent magnet motor with a high heat dissipation coefficient and active loss structure. Background Art

[0002] In recent years, with the continuous advancement of motor technology, the requirements for motor performance have become increasingly stringent. Permanent magnet synchronous motors (PMSMs) are high-performance, highly reliable AC motors that couple the armature magnetic field with the rotating magnetic field of the rotor's permanent magnet excitation to produce stable torque. They offer advantages such as simple structure, high power density, high torque density, and strong overload capacity, making them a promising alternative to traditional electromagnetic motors. They are widely used in aerospace, industrial servos, and electric vehicles.

[0003] However, despite their numerous advantages, permanent magnet motors (PMMs) suffer from high losses, compact structures, and poor heat dissipation. The uneven distribution of internal losses is becoming increasingly prominent, especially under high-speed, high-frequency operating conditions, where localized temperature rise becomes a key bottleneck restricting performance and reliability. Research has shown that internal heat, a source of internal motor losses during operation, increases both losses and temperature, significantly impacting the motor's lifespan. Currently, scholars both domestically and internationally have conducted extensive research on the design of permanent magnet motors and heat dissipation methods.

[0004] Domestic motor researchers have conducted detailed research on the temperature-rise characteristics of high-overload motors. Comparing the temperature-rise patterns of the motor's windings and housing under normal and high-temperature conditions, they found that, because the residual flux density of the permanent magnets decreases significantly at high temperatures, the magnetic load decreases. Therefore, to achieve the same output torque, the current must be increased, thus increasing the motor's electrical load. This results in increased copper losses and a higher temperature difference between the windings and housing compared to normal temperature.

[0005] In addition, other motor researchers have proposed a novel water-cooling topology. This cooling structure radially inserts several water-cooling disks into the stator core. These disks are in direct contact with heat sources such as the stator core and windings, effectively removing heat from the motor. To verify the cooling effectiveness of this structure, a conventional water-cooled motor and a motor with a water-cooling disk structure with the same specifications were fabricated. Temperature-rise testing showed that, under rated operating conditions, the water-cooling disk structure reduced winding temperature by over 20°C compared to a conventional water-cooling structure, and also reduced the temperature rise of the permanent magnets to a certain extent.

[0006] For permanent magnet motors, most of the existing temperature rise suppression measures involve some structural improvements on the motor housing, which can effectively suppress the temperature rise of the motor's high heat dissipation coefficient part, but the effect on suppressing the temperature rise on the inner side of the motor with a low heat dissipation coefficient is not significant. Summary of the Invention

[0007] To solve the above problems, the present invention discloses a high-torque permanent magnet motor with active loss in a high heat dissipation coefficient structure. An active loss ring is arranged on the outside of the motor to actively transfer the loss inside the motor to the active loss ring located on the outside, thereby reducing the maximum temperature rise inside the motor and solving the problem of limiting the motor's torque improvement capability due to the rise in hot spot temperature.

[0008] The present invention provides a high-torque permanent magnet motor with a high heat dissipation coefficient and active loss structure, comprising: a rotor and a stator located inside the rotor; an armature winding wound on the stator teeth of the stator; It is characterized by further comprising: Active loss ring, the rotor core has a higher conductivity coefficient than the rotor, and a higher heat dissipation coefficient than the stator and rotor. Its structure is a cylindrical structure with a continuous conductive loop; The active loss ring is connected to the rotor and can rotate synchronously with the rotor. The asynchronous rotating harmonics generated by the armature magnetic field can generate electromagnetic induction with the active loss ring and generate eddy current loss in the active loss ring. When the armature current is determined, the number and amplitude of the asynchronous rotating harmonics are fixed. The active loss ring actively consumes the asynchronous rotating harmonics, and the amount of asynchronous rotating harmonics consumed on the stator is small, so the core loss on the stator is small. By applying the active loss ring, the loss on the stator inside the radial direction of the motor can be actively transferred to the active loss ring with a high heat dissipation coefficient on the radial outside to reconstruct the heat source distribution.

[0009] Optionally, the active loss ring is made of a copper-silver composite alloy.

[0010] Optionally, the electrical conductivity of the active loss ring decreases gradually from the surface layer to the bottom layer.

[0011] Optionally, the bottom layer of the active loss ring is paved with 100% copper powder, the middle layer is paved with a mixture of 70% copper powder and 30% silver powder, and the surface layer is paved with a mixture of 30% copper powder and 70% silver powder.

[0012] Optionally, the active loss ring is fixed to the rotor surface by laser welding.

[0013] Optionally, the contact surface between the active loss ring and the rotor is provided with thermal grease.

[0014] Optionally, the surface of the active loss ring is provided with spiral guide microgrooves for guiding the directional consumption of asynchronous rotating harmonics.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The present invention applies an active loss ring to the high heat dissipation coefficient part of the motor, so that the asynchronous rotating harmonics are consumed in the active loss ring. Without increasing the overall loss of the motor, the loss in the motor can be actively transferred from the low heat dissipation coefficient part to the high heat dissipation coefficient part. Without increasing the overall loss of the motor, the distribution of the heat source in the motor can be controlled, the maximum temperature rise in the motor and the degree of distortion of the temperature rise part can be reduced, and the problem of limiting the torque improvement capability of the motor due to the increase in hot spot temperature can be solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic cross-sectional structure diagram along the axis of a high-torque permanent magnet motor with a high heat dissipation coefficient and active loss structure provided in some embodiments of the present invention; Figure 2 This is a radial cross-sectional diagram of a high-torque permanent magnet motor with a high heat dissipation coefficient and active loss provided in some embodiments of the present invention; Figure 3 This is a schematic diagram of the three-dimensional structure of an active loss ring of a high-torque permanent magnet motor with a high heat dissipation coefficient and active loss provided in some embodiments of the present invention.

[0017] List of Figure Symbols: 1-rotor, 101-rotor core, 102-permanent magnet, 2-stator, 201-stator core, 202-stator teeth, 203-armature winding, 3-active loss ring, 301-active loss ring bottom layer, 302-active loss ring middle layer, 303-active loss ring surface layer. DETAILED DESCRIPTION

[0018] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more. In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0019] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.

[0020] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0021] like Figure 1 and Figure 2 As shown, the present invention discloses a high-torque permanent magnet motor with a high heat dissipation coefficient and active loss structure, including a rotor 1 and a stator 2, wherein the rotor 1 includes a rotor core 101 and a permanent magnet 102, and the stator 2 includes a stator core 201, stator teeth 202 and an armature winding 203.

[0022] The present invention is aimed at the high torque density demand of electric vehicle motors and invents a permanent magnet synchronous motor with high torque output capacity and high efficiency. Most of the existing temperature rise suppression measures for traditional motors are to make some structural improvements on the motor casing, which can effectively suppress the temperature rise in the high heat dissipation coefficient area of ​​the motor, but the temperature rise suppression effect on the inner side of the motor with a low heat dissipation coefficient is not significant. On the basis of the traditional permanent magnet motor, the present invention sets an active loss ring in the high heat dissipation coefficient structural area, and the heat dissipation coefficient of the active loss ring 3 is higher than that of the stator 2 and the various parts in the rotor 1, thereby enhancing the ability of non-synchronous rotating harmonics to generate losses on the ring. Without increasing the total loss of the motor, the loss in the motor is actively migrated to the high heat dissipation coefficient part, and the heat source distribution is reconstructed in a way that increases the loss of the high heat dissipation coefficient structure. The motor of the present invention can reduce the maximum temperature rise and the degree of temperature rise distribution distortion, and solve the problem of limiting the motor torque improvement capability due to the increase in hot spot temperature. Therefore, the present invention has the characteristics of high flexibility and high torque output capability.

[0023] like Figure 1 and Figure 2 As shown, the stator core 201 and the rotor core 101 are made of silicon steel laminations or other magnetic conductive structures. The manufacturing process is the same as that of ordinary motors. The stator core 201 is made of silicon steel sheets stacked on the inner stator base. The positioning ribs are welded to the machine base ring plate through the support plate, and the core is pressed into a whole by tension bolts through the upper and lower tooth pressure plates. The rotor core 101 is cup-shaped, made of stacked silicon steel sheets, and fixed to the inner wall of the rotating shell.

[0024] like Figure 2 As shown, the stator core 201 of the present invention can be split into stator blocks of the same shape, each of which only includes a stator yoke and a stator tooth. In the manufacture of the motor stator, stator blocks of the same shape and simple structure can reduce the difficulty of the manufacturing process.

[0025] like Figure 1 and Figure 2 As shown, the rotor 1 is located outside the stator 2, and the active loss ring 3 is made of a high conductivity material. The conductivity of the active loss ring 3 is higher than that of the rotor core 101, and the heat dissipation coefficient is higher than that of the stator 2 and the rotor 1. Its structure is a cylindrical structure with a continuous conductive loop.

[0026] When the motor is running, the active loss ring 3 rotates synchronously with the rotor 1. Since the conductivity of the active loss ring 3 is higher than that of the rotor core 101, the asynchronous rotating harmonics generated by the armature magnetic field are electromagnetically induced by the active loss ring 3, and eddy current loss is generated in the active loss ring 3. At this time, the amount of asynchronous rotating harmonics consumed on the stator 2 is small, and the core loss on the stator 2 is small.

[0027] like Figure 1 and Figure 2As shown, the active loss ring 3 is fixed to the surface of the rotor 1 by laser welding, which can withstand the centrifugal force of the motor rotation and avoid the risk of high-speed separation. In addition, thermal conductive silicone grease is provided on the contact surface with the rotor 1. The thermal conductive silicone grease fills the microscopic bumps on the contact surface, which can increase the effective thermal contact area. Under the same loss, the temperature rise of the rotor 1 will be significantly reduced.

[0028] like Figure 2 As shown, the armature winding 203 adopts fractional slot concentrated winding, which is wound on the stator teeth 202. In this embodiment, since the ends of the fractional slot concentrated winding are shorter than those of traditional distributed windings, copper loss is low, which helps to reduce the temperature rise when the motor is working under load.

[0029] like Figure 3 As shown, the active loss ring 3 is made of a copper-silver composite alloy. Since the temperature of the motor can reach 120-150°C during continuous operation, the material needs to have high-temperature stability. The copper-silver composite alloy material maintains stable electrical and thermal conductivity at high temperatures, effectively reducing the risk of demagnetization of the permanent magnet 102, making it suitable for high-temperature working conditions of electric vehicle drive motors.

[0030] like Figure 3 As shown, the electrical conductivity of the active loss ring 3 is distributed in a gradient decreasing manner from the surface layer to the bottom layer. Since the electrical conductivity of silver is higher than that of copper, copper and silver can be layered in proportion. The bottom layer 301 of the active loss ring is 100% copper powder, the middle layer 302 of the active loss ring is paved with a mixture of 70% copper powder and 30% silver powder, and the surface layer 303 of the active loss ring is paved with a mixture of 30% copper powder and 70% silver powder. The electrical conductivity of the active loss ring 3 can be distributed in a gradient decreasing manner from the surface layer to the bottom layer.

[0031] like Figure 3 As shown, the thickness of the active loss ring 3 is 1.5-2 mm, which reduces the manufacturing cost of the active loss ring 3 while meeting the requirements.

[0032] like Figure 3 As shown, the surface of the active loss ring 3 is processed with spiral guide micro grooves to guide the directional consumption of asynchronous rotating harmonics.

[0033] The active loss ring proposed by the present invention has a wide range of applications and is applicable to permanent magnet motors of various structures, such as outer rotor motors and inner rotor motors.

[0034] The high-torque permanent magnet motor with a high heat dissipation coefficient and active losses proposed in this example actively transfers losses radially inside the motor to the high-heat dissipation coefficient active loss ring 3 on the radially outer side. This reduces the maximum temperature rise and the degree of temperature rise distribution distortion, thus resolving the problem of hot spot temperature rise limiting the motor's torque capacity. Based on this characteristic, this motor can be applied to any application requiring high torque density, such as robotic joints and electric vehicle drives.

[0035] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A high-torque permanent magnet motor with a high heat dissipation coefficient and active loss, comprising: A rotor (1) and a stator (2) located inside the rotor (1); An armature winding (203) is wound on the stator teeth (202) of the stator (2); It is characterized by further comprising: An active loss ring (3), a rotor core (101) having a higher conductivity coefficient than the rotor (1), a higher heat dissipation coefficient than the stator (2) and the rotor (1), and a cylindrical structure having a continuous conductive loop; The active loss ring (3) is connected to the rotor (1) and can rotate synchronously with the rotor (1); the asynchronous rotating harmonics generated by the armature magnetic field can generate electromagnetic induction with the active loss ring (3) and generate eddy current loss in the active loss ring (3); When the armature current is determined, the number and amplitude of the non-synchronous rotating harmonics are fixed, the active loss ring (3) actively consumes the non-synchronous rotating harmonics, and the amount of non-synchronous rotating harmonics consumed on the stator (2) is small, so the core loss on the stator (2) is small; by applying the active loss ring (3), the loss on the stator (2) inside the radial direction of the motor can be actively transferred to the active loss ring (3) with a high heat dissipation coefficient on the radial outside to reconstruct the heat source distribution.

2. The high-torque permanent magnet motor with high heat dissipation coefficient and active loss according to claim 1, characterized in that: The active loss ring (3) is made of a copper-silver composite alloy.

3. The high-torque permanent magnet motor with high heat dissipation coefficient and active loss according to claim 1, characterized in that: The electrical conductivity of the active loss ring (3) decreases gradually from the surface layer to the bottom layer.

4. The high-torque permanent magnet motor with high heat dissipation coefficient and active loss according to claim 1, characterized in that: The bottom layer of the active loss ring (3) is made of 100% copper powder, the middle layer is made of a mixture of 70% copper powder and 30% silver powder, and the surface layer is made of a mixture of 30% copper powder and 70% silver powder.

5. The high-torque permanent magnet motor with high heat dissipation coefficient and active loss according to claim 1, characterized in that: The active loss ring (3) is fixed to the surface of the rotor (1) by laser welding.

6. The high-torque permanent magnet motor with high heat dissipation coefficient and active loss according to claim 1, characterized in that: The contact surface between the active loss ring (3) and the rotor (1) is provided with thermal conductive silicone grease.

7. The high-torque permanent magnet motor with high heat dissipation coefficient and active loss according to claim 1, characterized in that: The surface of the active loss ring (3) is provided with spiral guide microgrooves for guiding the directional consumption of asynchronous rotating harmonics.

8. The high-torque permanent magnet motor with high heat dissipation coefficient and active loss according to claim 1, characterized in that: The thickness of the active loss ring 3 is 1.5-2 mm.

Images