A high-speed permanent magnet motor

Abstract

The utility model provides a kind of high-speed permanent magnet motor belongs to motor design technical field, include: motor shell, inside installation stator assembly, stator winding, rotor assembly, motor rotating shaft and bearing, stator assembly, stator assembly is composed of stator core and stator slot, and stator winding is embedded in the groove bottom position of stator slot.The utility model design structure is reasonable and compact, and the structure of long-tooth stator core and stator slot cooperate groove bottom arrangement stator winding releases radial space, so that bearing is embedded installation, shortens bearing span, improves critical speed and mechanical stability;Axial heat dissipation flow passage design realizes directional cooling while optimizing electromagnetic efficiency, solves permanent magnet demagnetization risk;Solid permanent magnet small shaft diameter embedded structure ensures the strength of rotor at the same time, effectively reduces centrifugal load and wind abrasion loss, improves high-speed operation reliability;Make the high power density of motor and ultrahigh speed in compact space obtain synergistic breakthrough.

Description

Technical Field

[0001] This utility model relates to the field of motor design technology, and in particular to a high-speed permanent magnet motor. Background Technology

[0002] High-speed permanent magnet motors are widely used in hydrogen fuel cell air compressors, flywheel energy storage, and other fields due to their high power density and excellent efficiency. In existing technologies, embedded permanent magnet motors (IPMs) embed permanent magnets into the rotor core slots, forcing an increase in rotor diameter. The rotor centrifugal force is proportional to the square of the diameter, and material strength limits the speed that can be increased further. Simultaneously, the multi-pole design doubles the power supply frequency, and iron losses increase with the 1.3-1.5 power of the frequency, significantly reducing efficiency. Surface-mounted permanent magnet motors (SPMs) use a permanent magnet with a sheath structure, and the single-pole pair design requires a 180° span coil, causing the winding ends to protrude axially. To avoid this, the bearings are forced to move outwards, increasing the span and limiting the rotor's critical speed.

[0003] While recent advancements in solid permanent magnet embedded rotor designs have reduced rotor diameter, their stators still utilize short-tooth, equal-width slots. This type of structure requires the windings to fill the slot cavities to maintain tooth magnetic flux density, inevitably resulting in the coil ends protruding outwards. Attempting to place the windings at the bottom of the slots introduces a triple problem: insufficient magnetic field strength at the bottom of the slots, leading to decreased electromagnetic torque; saturation of the tooth tip magnetic flux density, increasing iron losses; and insufficient space for wire bending, resulting in continued outward protrusion at the ends. These issues prevent the bearing span from being shortened, hindering the increase of the critical speed.

[0004] A more prominent contradiction lies in the trade-off between heat dissipation and efficiency. Traditional full-slot windings impede cooling airflow, causing the permanent magnet temperature to rise continuously and significantly increasing the risk of demagnetization. Increasing the number of pole pairs can reduce iron losses, but this leads to increased inverter losses. Existing technologies have consistently failed to synergistically optimize mechanical stability, electromagnetic efficiency, and thermal management performance under high-speed conditions. This results in an irreconcilable situation in radial space between electromagnetic performance optimization and mechanical dynamic enhancement, leading to a long-standing passive predicament for high-speed motors: "increasing speed inevitably sacrifices power, and increasing power inevitably limits speed." Utility Model Content

[0005] This invention proposes a high-speed permanent magnet motor to solve the problem mentioned in the background art that the existing technology has always been unable to synergistically optimize mechanical stability, electromagnetic efficiency and thermal management performance under high-speed conditions; and that high-speed motors have long been trapped in a passive situation where "increasing speed inevitably sacrifices power, and increasing power inevitably limits speed".

[0006] The technical solution of this utility model is implemented as follows:

[0007] The motor housing contains the stator assembly, stator windings, rotor assembly, motor shaft, and bearings.

[0008] The stator assembly consists of a stator core and stator slots. The stator core has a cylindrical structure with multiple radially extending stator slots evenly distributed on its inner circumference. Each stator slot extends non-through from the inner circumference to the outer circumference of the stator core, forming a deep slot structure for embedding the stator winding. The stator slots have a long tooth-shaped structure in the radial cross-section of the stator core, forming a long tooth-shaped stator core.

[0009] The stator winding is embedded at the bottom of the stator slot, and the inner diameter of the end of the stator winding is larger than the inner diameter of the long tooth stator core.

[0010] Rotor assembly, including motor shaft and permanent magnet;

[0011] The bearing is placed in the groove formed by the end of the stator winding and the long toothed stator core.

[0012] By adopting the above technical solutions, traditional limitations are broken through the stator topology reconstruction. The rotor uses a solid cylindrical permanent magnet directly embedded in the motor shaft, which reduces the diameter, achieving rotor weight reduction and lowering centrifugal force and windage loss. The stator adopts a long-tooth stator core and a method of winding the stator windings at the bottom of the stator slots, which can greatly shorten the bearing span, making the structure compact, increasing the critical speed, reducing iron loss and windage loss, while the open channels improve heat dissipation capacity, thus improving motor efficiency. Finally, through electromagnetic-mechanical synergistic optimization, the traditional bottleneck of high-speed, high-power motors is broken through.

[0013] Preferably, the stator winding adopts a double-layer short-pitch winding or sinusoidal winding design.

[0014] By adopting the above technical solutions, large-angle spans at the winding end faces can be avoided, phase band harmonics of the motor windings can be improved, and iron losses and motor heat generation can be reduced.

[0015] Preferably, the stator winding is only located in the bottom region of the stator slot, and the stator winding end inner diameter is increased.

[0016] By adopting the above technical solution, the inner diameter of the stator winding end face is much larger than the inner diameter of the long-tooth stator core, and because the winding end face protrudes, it forms a groove that can accommodate the bearing. This shortens the bearing span, thereby increasing the critical speed, and the internal space of the motor is also utilized more efficiently.

[0017] Preferably, the stator also includes a gap between the inner ring of the stator winding and the inner ring of the stator core in the stator slot, forming an axial cooling and heat dissipation channel.

[0018] By adopting the above technical solution, an axial cooling and heat dissipation channel is formed in the area of ​​the stator slot without winding filling structure. A certain part of the heat generated by the permanent magnet during operation can be dissipated, avoiding demagnetization of the permanent magnet due to high temperature. The structural design of the cooling and heat dissipation channel being directly connected to the rotor air gap results in the shortest heat dissipation path. The non-contact physical isolation between the cooling and heat dissipation channel and the permanent magnet provides dual protection of insulation and electromagnetic performance.

[0019] Preferably, the cross-sectional shape of the cooling and heat dissipation channel is an open trapezoid.

[0020] By adopting the above technical solution, the trapezoidal cross section can reduce turbulence, and the wide tooth root of the trapezoid can resist electromagnetic vibration deformation.

[0021] Preferably, in the rotor assembly, the motor shaft is installed at the center of the motor housing, and the permanent magnet has a solid cylindrical structure and is embedded in the center of the motor shaft.

[0022] By adopting the above technical solution, a high-performance solid cylindrical permanent magnet is embedded in the motor shaft, which can make full use of the motor rotor shaft diameter, reduce rotor weight, effectively reduce centrifugal force, and enable the motor to support higher speeds. Under the premise of meeting the requirements of motor electromagnetic performance and rotor material strength, the motor rotor shaft diameter can be designed to be smaller.

[0023] Preferably, the bearing is directly mounted at the end of the stator winding-free portion of the long-toothed stator core.

[0024] By adopting the above technical solution, the installation space of the bearing is further freed up, the bearing span is shortened, and the critical speed is further improved.

[0025] By adopting the above technical solution, the beneficial effects of this utility model are as follows:

[0026] This utility model features a reasonable and compact design. By using a long-toothed stator core and stator slots to accommodate the stator windings at the bottom of the slots, radial space is released, allowing for embedded bearing installation, shortening the bearing span, and improving critical speed and mechanical stability. The axial heat dissipation channel design optimizes electromagnetic efficiency while achieving directional cooling, thus mitigating the risk of permanent magnet demagnetization. The solid permanent magnet with a small shaft diameter embedded structure ensures rotor strength while effectively reducing centrifugal load and windage loss, improving high-speed operation reliability. This allows the motor to achieve a synergistic breakthrough in high power density and ultra-high speed within a compact space. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of this utility model 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 this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is an axial cross-sectional view of the present invention;

[0029] Figure 2 This is a radial cross-sectional view of the present invention;

[0030] in:

[0031] 1. Stator core; 2. Stator slot; 3. Stator winding; 4. Bearing; 5. Cooling and heat dissipation channel; 6. Cylindrical permanent magnet; 7. Motor shaft; 8. Protective layer; 9. Motor housing. Detailed Implementation

[0032] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0033] refer to Figures 1 to 2 A high-speed permanent magnet motor, comprising:

[0034] 3. Stator assembly, stator winding, rotor assembly and bearing.

[0035] The stator assembly, specifically the stator core 1, is mechanically fixedly mounted inside the motor housing 9. The stator core 1 has a cylindrical structure with multiple radially extending stator slots 2 evenly distributed along its inner circumference. The stator slots 2 have a long tooth-shaped radial cross-section on the stator core 1. The stator core 1 and stator slots 2 are integral, and the radial cross-section of the stator core 1 also has a long tooth-shaped structure. Stator windings 3 are arranged in the bottom region of the stator slots 2. Within each individual stator slot 2, a certain gap exists between the stator winding 3 and the inner ring of the stator core 1. This gap creates an axially continuous cooling and heat dissipation channel 5 from the slot opening to the inner circle of the stator. The stator windings 3 adopt a double-layer short-pitch topology and are only arranged in the bottom region of the stator slots 2. Since the inner diameter of the stator winding 3 end is much larger than the inner diameter of the long tooth stator core 1, the two together form an inwardly recessed groove. This groove can be used to place the bearing 4, effectively releasing the radial installation space of the bearing 4, thereby compressing the bearing 4 span to the theoretical minimum value of the traditional motor structure.

[0036] The rotor assembly, with the motor shaft 7 mounted inside the motor housing 9 via bearings 4, consists of a solid cylindrical permanent magnet 6 embedded within the motor shaft 7, forming an integrated rotor structure. Specifically, the cooling and heat dissipation channel 5 has a trapezoidal cross-section, which helps improve cooling efficiency. Simultaneously, the wide tooth root structure of the long-tooth stator core 1 enhances its resistance to electromagnetic vibration. The motor uses multiple pole pairs, resulting in a small span for the stator winding 3, which significantly reduces the axial extension length at the winding ends, thus reducing the overall size of the motor. The tooth tip width and tooth root width of the long-tooth stator core are maintained within a specific ratio range, and the tooth height and stator inner diameter are kept in an optimized proportion, ensuring that the geometric configuration ensures that the cross-sectional area of ​​the cooling and heat dissipation channel 5 is within an effective range after the stator winding 3 is installed. During the operation of the high-speed permanent magnet motor, the heat generated by the winding current can be conducted to the back of the long-tooth stator core 1 through the copper wire at the bottom of the slots and further dissipated. The heat generated by the solid cylindrical permanent magnet 6 is dissipated through the axial cooling and heat dissipation channel 5. This heat dissipation design significantly improves the overall heat dissipation performance of the motor. By effectively suppressing the temperature rise of the permanent magnet, it can prevent the permanent magnet from demagnetizing due to high temperature, thereby ensuring the stable operation and long life of the motor.

[0037] Specifically, during assembly, the motor shaft 7 is fitted onto the outer surface of the permanent magnet 6. When installing the bearing 4, first combine the long-toothed stator core 1 with the end of the stator winding 3, then insert the motor shaft 7 into the stator cavity, install the bearing 4, and then fit the motor housing 9. During final assembly, the stator winding 3 is embedded in the slot bottom, and the winding end is bent into a ring structure, with the inner ring of the end maintaining a specific gap with the outer ring of the bearing 4. The motor housing 9 can be equipped with a ring-shaped air collector, the outlet of which connects to the back of the stator, forming a closed cooling circulation loop.

[0038] Preferably, the surface of the permanent magnet has a protective layer.

[0039] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A high speed permanent magnet electric machine characterized by, include: The motor housing (9) contains a stator assembly, stator windings (3), rotor assembly and bearings (4). The stator assembly is installed between the motor housing (9) and the rotor assembly; The stator winding (3) is located at the bottom of the stator slot (2) in the stator assembly, and the inner diameter of the end of the stator winding (3) is larger than the inner diameter of the stator core (1). The rotor assembly is located at the center of the stator assembly; The bearing (4) is located close to the stator core (1).

2. A high speed permanent magnet electric machine according to claim 1, characterized in that: The stator assembly includes a stator core (1) and stator slots (2). The stator core (1) has a cylindrical structure with multiple radially extending stator slots (2) evenly distributed on its inner circumference. The stator slots (2) have a long tooth-shaped structure in the radial section of the stator core (1), and the radial section of the stator core (1) also has a long tooth-shaped structure.

3. A high speed permanent magnet electric machine according to claim 1, characterized in that: The stator winding (3) adopts a double-layer short-pitch winding or sinusoidal winding design.

4. A high speed permanent magnet electric machine as recited in claim 1, characterized by: In the stator slot (2), a cooling and heat dissipation channel (5) is formed between the inner ring of the stator winding (3) and the inner ring of the stator core (1) in the direction of the axis of the stator core (1).

5. A high speed permanent magnet electric machine according to claim 4, characterized in that: The cross-sectional shape of the cooling and heat dissipation channel (5) is an open trapezoid.

6. A high speed permanent magnet electric machine as recited in claim 1, characterized by: The rotor assembly includes a motor shaft (7) and a permanent magnet (6).

7. A high speed permanent magnet electric machine as claimed in claim 6, characterized in that: In the rotor assembly, the motor shaft (7) is installed at the center of the motor housing (9), and the permanent magnet (6) is a solid cylindrical structure and is embedded in the center of the motor shaft (7).

8. A high speed permanent magnet electric machine as recited in claim 6, characterized by: The surface of the permanent magnet (6) has a protective layer (8).

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