Toothed bearingless switched reluctance motor

Abstract

The application relates to a bearingless switched reluctance motor with a tooth-shaped structure, which comprises a doubly salient stator, the doubly salient stator comprising a rotor and a stator sleeved on the periphery of the rotor; a plurality of groups of stator teeth extending to the rotor are arranged on the stator; a plurality of groups of rotor teeth extending outward are arranged on the rotor; a plurality of sets of stator windings are arranged on the stator teeth; an inner auxiliary slot of a stator tooth pole is arranged on the inner side of the stator tooth; an inner auxiliary slot of a rotor tooth pole is arranged on the rotor tooth of the rotor. The application provides the bearingless switched reluctance motor with the tooth-shaped structure, which can increase the magnetic resistance, change the magnetic line distribution in the motor, weaken the radial magnetic density in the air gap, increase the tangential magnetic density, finally increase the average torque, greatly reduce the torque ripple, and improve the performance of the bearingless switched reluctance motor.

Description

Technical Field

[0001] This invention relates to the field of machinery, and more specifically to a bearingless switched reluctance motor with a toothed structure. Background Technology

[0002] In the prior art, for example, there is an existing patent, patent number: CN202110629280.2, patent title: A novel switched reluctance motor with a stator and rotor tooth profile; the disclosed novel switched reluctance motor with a stator and rotor tooth profile includes a stator, a rotor, a shaft, stator arc-shaped teeth, rotor auxiliary slots, and rotor ventilation openings. The rotor is embedded in the stator, the rotor is coaxial with the stator, the shaft is located at the center of the rotor, the stator arc-shaped tooth structure is an inward arc-shaped structure on both sides of the stator teeth, the rotor auxiliary slots are rectangular slots on both sides of the rotor teeth, and the rotor ventilation openings are located on the rotor.

[0003] Due to the unique doubly salient pole structure and switching power supply mode of switched reluctance motors, the stator and rotor salient poles are highly saturated during operation, resulting in a significant edge flux effect and highly saturated magnetic circuit. This makes the magnetic circuit characteristics more complex than other motors, with parameters such as current and magnetic flux exhibiting nonlinear changes, leading to more pronounced torque ripple. Furthermore, the electromagnetic torque of a switched reluctance motor is synthesized from the torques of two adjacent phases. The nonlinear current changes caused by the switching power supply mode and high magnetic circuit saturation also contribute to torque ripple during commutation.

[0004] Although the three-phase 12 / 8-pole bearingless switched reluctance motor is a special type of switched reluctance motor, its doubly salient pole structure and switching power supply method remain unchanged. Therefore, the problem of large torque ripple still exists, hindering the further development of bearingless switched reluctance motors. Summary of the Invention

[0005] This invention overcomes the shortcomings of the prior art and provides a bearingless switched reluctance motor with a toothed structure, which can increase the magnetic reluctance and change the distribution of magnetic lines of force inside the motor, thereby weakening the radial magnetic flux density in the air gap and increasing the tangential magnetic flux density, ultimately achieving the purpose of increasing the average torque and significantly reducing torque ripple, which is beneficial to improving the performance of the bearingless switched reluctance motor.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a bearingless switched reluctance motor with a toothed structure, comprising: a doubly salient pole stator and rotor, the doubly salient pole stator and rotor including a rotor and a stator sleeved around the rotor; the stator is provided with a plurality of sets of stator teeth extending toward the rotor; the rotor is provided with a plurality of sets of rotor teeth extending outward; a plurality of sets of stator windings are wound on the stator teeth; the inner side of the stator teeth is provided with auxiliary slots inside the stator tooth poles; the rotor teeth of the rotor are provided with auxiliary slots inside the rotor tooth poles.

[0007] In a preferred embodiment of the present invention, the auxiliary slots inside the rotor tooth poles are parallelogram-shaped auxiliary slots.

[0008] In a preferred embodiment of the present invention, the auxiliary groove inside the stator tooth pole is a square auxiliary groove.

[0009] In a preferred embodiment of the present invention, the rotor rotation direction during motor operation is counterclockwise; the stator tooth edge is the edge of the stator tooth in the contact direction between the stator tooth and the rotor tooth when the motor rotor rotates; the side length of the auxiliary slot inside the stator tooth pole is 3.03%-15.15% of the stator pole width, the distance from the stator tooth edge is 1.51%-15.1% of the stator pole width, and the distance from the stator tooth tip is 1.21%-6.05% of the stator pole height.

[0010] In a preferred embodiment of the present invention, the rotor rotation direction during motor operation is counterclockwise; the rotor tooth edge is the edge of the rotor tooth in the contact direction between the stator tooth and the rotor tooth when the motor rotor rotates; the side length of the auxiliary slot inside the rotor tooth pole is 14.3%-28.6% of the rotor pole height, the height is 7.75%-10.85% of the rotor pole width, the distance from the rotor tooth edge is 1.16%-3.48% of the rotor pole width, and the distance from the rotor tooth tip is 1.43%-5.73% of the rotor pole height.

[0011] In a preferred embodiment of the present invention, it is applicable to a three-phase 12 / 8-pole switched reluctance motor or a three-phase 12 / 8-pole bearingless switched reluctance motor; the stator adopts 12 sets of stator windings.

[0012] In a preferred embodiment of the present invention, the torque ripple coefficient is: (T1-T2) / T3=0.73; where T1 is the maximum torque value when the motor is running stably, T2 is the minimum torque value when the motor is running stably, T3 is the average torque value when the motor is running stably, and the torque ripple coefficient is 0.73.

[0013] In a preferred embodiment of the present invention, the auxiliary groove inside the rotor tooth pole is disposed on the tooth tip of the rotor tooth on the side where the rotor tooth and stator tooth first contact; the auxiliary groove inside the stator tooth pole is disposed on the tooth tip of the stator tooth on the side where the stator tooth and rotor tooth first contact.

[0014] In a preferred embodiment of the present invention, a method for changing the average torque of a motor, employing a bearingless switched reluctance motor with a toothed structure, includes the following: enhancing the average torque of the motor by changing the structure of the motor stator and rotor, thereby significantly reducing motor torque ripple.

[0015] The rotor teeth have parallelogram auxiliary slots inside, and the stator teeth have square auxiliary slots inside. These can increase the magnetic resistance in the magnetic circuit, change the direction of the magnetic lines of force, thereby weakening the radial magnetic flux density in the air gap and increasing the tangential magnetic flux density, thus increasing the average torque and significantly reducing torque pulsation.

[0016] Magnetic flux always closes along the path of least magnetic resistance. By creating parallelogram auxiliary slots inside the rotor tooth poles, the magnetic resistance in the magnetic circuit can be increased, and the direction of the magnetic lines of force can be changed. This allows the magnetic lines of force to enter the rotor through the magnetic circuit between the parallelogram auxiliary slots and the rotor tooth tips, thereby changing the angle at which the magnetic flux enters the rotor teeth. This reduces the radial magnetic flux density in the air gap and increases the tangential magnetic flux density, thereby increasing the average torque and reducing the inherent torque pulsation.

[0017] Square auxiliary slots are created inside the stator teeth, increasing the magnetic resistance in the magnetic circuit and changing the direction of the magnetic lines of force. This causes the magnetic lines of force to be compressed between the stator teeth edges in the contact direction of the stator and rotor teeth when the motor rotor rotates, as the stator and rotor teeth are in contact. This allows some of the magnetic lines of force to enter the rotor teeth through the non-overlapping area of ​​the stator and rotor teeth. The radial force generated in the overlapping area of ​​the stator and rotor teeth is the effective radial force, while the radial component of the magnetic lines of force in the non-overlapping area of ​​the stator and rotor teeth is an ineffective component. The tangential force is generated at the edge of the two overlapping areas, so the tangential component in that part is an effective component. Ultimately, this can further reduce torque pulsation.

[0018] This invention addresses the shortcomings of the prior art, and its beneficial effects are as follows: This invention provides a novel tooth profile structure that can improve average torque and significantly reduce motor torque ripple, thereby improving motor performance. The parallelogram auxiliary slots inside the rotor teeth weaken the radial magnetic flux density in the air gap and increase the tangential magnetic flux density, thus increasing torque and reducing motor torque ripple. The square auxiliary slots inside the stator teeth increase magnetic reluctance, change the direction of magnetic lines of force on the stator teeth, optimize the air gap magnetic flux density waveform, further reduce motor torque ripple, and contribute to improving motor performance. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a novel wide-rotor-tooth bearingless switched reluctance motor with a preferred embodiment of the present invention. Figure 2This is a schematic diagram of the stator teeth of a bearingless switched reluctance motor with a novel tooth structure according to a preferred embodiment of the present invention. Figure 3 This is a schematic diagram of the rotor teeth of a bearingless switched reluctance motor with a novel tooth structure according to a preferred embodiment of the present invention. Figure 4 This is a schematic diagram showing the simulation results comparing the torque of a novel wide-rotor tooth bearingless switched reluctance motor with a new tooth structure according to the present invention with that of a traditional wide-rotor tooth bearingless switched reluctance motor. Figure 5 The prototype dimensions of a bearingless switched reluctance motor with a novel toothed structure for a wide rotor tooth according to the present invention are shown below. Figure 6 This is a comparison diagram of the radial magnetic flux density of the original model and the improved model; Figure 7 The original model has a maximum tangential magnetic flux density of 0.31T, while the improved model has a maximum tangential magnetic flux density of 0.43T, an increase of 38.7%. Figure 8 It is a schematic diagram of the original model's magnetic field lines. Figure 9 This is a schematic diagram of the improved model's magnetic field line orientation. Figure 10 It is a simulation diagram of the magnetic field lines in the original model; Figure 11 It is a simulation diagram of the improved magnetic field line orientation; Figure 12 This is a schematic diagram showing the state of the average torque of the motor with the side length of the parallelogram auxiliary slot inside the rotor tooth pole ranging from 1 to 2 mm. Figure 13 This is a schematic diagram showing the state of motor torque pulsation when the side length of the parallelogram auxiliary slot inside the rotor tooth pole is in the range of 1-2mm. Figure 14 This is a schematic diagram showing the state of the average torque of the motor when the height of the parallelogram auxiliary slot inside the rotor tooth pole is in the range of 1-1.4mm. Figure 15 This is a schematic diagram showing the state of motor torque pulsation when the height of the parallelogram auxiliary slot inside the rotor tooth pole is in the range of 1-1.4mm. Figure 16 This is a schematic diagram showing the effect of the distance between the parallelogram auxiliary slot inside the rotor tooth pole and the edge of the rotor tooth on the average torque of the motor when the distance is in the range of 0.15-0.45mm. Figure 17 This is a schematic diagram illustrating the effect of the distance between the parallelogram auxiliary slot inside the rotor tooth pole and the edge of the rotor tooth in the range of 0.15-0.45mm on the motor torque pulsation. Figure 18This is a schematic diagram showing the effect of the distance between the parallelogram auxiliary slot inside the rotor tooth pole and the tip of the rotor tooth on the average torque of the motor when the distance is in the range of 0.1-0.4mm. Figure 19 This is a schematic diagram showing the effect of the distance between the parallelogram auxiliary slot inside the rotor tooth pole and the tip of the rotor tooth on the motor torque pulsation when the distance is in the range of 0.1-0.4mm. Figure 20 This is a schematic diagram showing the effect of the square auxiliary slots inside the stator teeth with a side length ranging from 0.2 to 1 mm on the average torque of the motor. Figure 21 This is a schematic diagram showing the effect of the square auxiliary slot inside the stator tooth pole with a side length ranging from 0.2 to 1 mm on the motor torque pulsation. Figure 22 This is a schematic diagram showing the influence of the distance between the square auxiliary slot inside the stator tooth pole and the edge of the stator tooth in the range of 0.1-1mm on the average torque of the motor. Figure 23 This is a schematic diagram illustrating the effect of the distance between the square auxiliary slot inside the stator tooth pole and the stator tooth edge on the motor torque pulsation when the distance is in the range of 0.1-1mm. Figure 24 This is a schematic diagram showing the effect of the distance between the square auxiliary slot inside the stator tooth pole and the stator tooth tip on the average torque of the motor when the distance is 0.2-1mm. Figure 25 This is a schematic diagram illustrating the effect of the distance between the square auxiliary slot inside the stator tooth pole and the stator tooth tip on the motor torque pulsation when the distance is 0.2-1mm. Wherein, 1-stator; 2-rotor; 3-stator winding; 4-stator tooth; 5-rotor tooth; 6-square auxiliary slot; 7-parallelogram auxiliary slot; 8-stator tooth edge; 9-rotor tooth edge. Implementation

[0020] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. These drawings are simplified schematic diagrams, which are only used to illustrate the basic structure of the present invention and therefore only show the components relevant to the present invention. Example

[0021] like Figures 1-25 As shown, a bearingless switched reluctance motor with a toothed structure includes: a double salient pole stator and rotor, including a rotor 2, and a stator 1 and 12 sets of stator windings 3 sleeved around the rotor 2. Both the stator 1 and the rotor 2 are salient pole structures. The stator 1 is provided with several sets of stator teeth 4 extending towards the rotor 2; the rotor 2 is provided with several sets of rotor teeth 5 extending outward; and several sets of stator windings 3 are wound on the stator teeth 4.

[0022] The stator tooth 4 has an internal auxiliary slot on its inner side; the internal auxiliary slot of the stator tooth is a square auxiliary slot 6. The rotor 2 rotates counterclockwise when the motor is running; the rotor tooth edge 9 is the edge of the rotor tooth 5 in the contact direction between the stator tooth 4 and the rotor tooth 5 when the motor rotor 2 rotates; the side length of the internal auxiliary slot of the rotor tooth is 14.3%-28.6% of the height of the rotor 2 pole, the height is 7.75%-10.85% of the width of the rotor 2 pole, the distance from the rotor tooth edge 9 is 1.16%-3.48% of the width of the rotor 2 pole, and the distance from the tip of the rotor tooth 5 is 1.43%-5.73% of the height of the rotor 2 pole.

[0023] The rotor teeth 5 of rotor 2 are provided with auxiliary slots inside the rotor tooth poles. The auxiliary slots inside the rotor tooth poles are parallelogram auxiliary slots 7. Specifically, one side of the parallelogram is parallel to the side of the rotor tooth 5, and the other side corresponds to the top arc of the rotor tooth 5. The rotor 2 rotates in the counterclockwise direction when the motor is running; the stator tooth edge 8 is the tooth edge of the stator tooth 4 in the contact direction between the stator tooth 4 and the rotor tooth 5 when the motor rotor 2 rotates; the side length of the auxiliary slot inside the stator tooth pole is 3.03%-15.15% of the width of the stator 1 pole, the distance from the stator tooth edge 8 is 1.51%-15.1% of the width of the stator 1 pole, and the distance from the top of the stator tooth 4 is 1.21%-6.05% of the height of the stator 1 pole.

[0024] Specifically, the torque ripple coefficient is (T1-T2) / T3=0.73; where T1 is the maximum torque value when the motor is running stably, T2 is the minimum torque value when the motor is running stably, and T3 is the average torque value when the motor is running stably.

[0025] The auxiliary groove inside the rotor tooth pole is set on the tooth end of the rotor tooth 5 on the side where the rotor tooth 5 and the stator tooth 4 first contact; the auxiliary groove inside the stator tooth pole is set on the tooth end of the stator tooth 4 on the side where the stator tooth 4 and the rotor tooth 5 first contact. Example

[0026] like Figures 1-25 As shown, a bearingless switched reluctance motor with a toothed structure includes: a double salient pole stator and rotor 2, including a rotor 2, and a stator 1 and 12 sets of stator windings 3 sleeved around the rotor 2. Both the stator 1 and the rotor 2 are salient pole structures. The stator 1 is provided with several sets of stator teeth 4 extending towards the rotor 2; the rotor 2 is provided with several sets of rotor teeth 5 extending outward; and several sets of stator windings 3 are wound on the stator teeth 4.

[0027] The stator tooth 4 has an internal auxiliary slot on its inner side; the internal auxiliary slot of the stator tooth is a square auxiliary slot 6. The rotor 2 rotates counterclockwise when the motor is running; the rotor tooth edge 9 is the edge of the rotor tooth 5 in the contact direction between the stator tooth 4 and the rotor tooth 5 when the motor rotor 2 rotates; the side length of the internal auxiliary slot of the rotor tooth is 14.3%-28.6% of the height of the rotor 2 pole, the height is 7.75%-10.85% of the width of the rotor 2 pole, the distance from the rotor tooth edge 9 is 1.16%-3.48% of the width of the rotor 2 pole, and the distance from the tip of the rotor tooth 5 is 1.43%-5.73% of the height of the rotor 2 pole.

[0028] The rotor teeth 5 of rotor 2 are provided with auxiliary slots inside the rotor tooth poles. The auxiliary slots inside the rotor tooth poles are parallelogram auxiliary slots 7. The rotor 2 rotates in the counterclockwise direction when the motor is running; the stator tooth edge 8 is the edge of the stator tooth 4 in the contact direction between the stator tooth 4 and the rotor tooth 5 when the motor rotor 2 rotates; the side length of the auxiliary slot inside the stator tooth pole is 3.03%-15.15% of the width of the stator 1 pole, the distance from the stator tooth edge 8 is 1.51%-15.1% of the width of the stator 1 pole, and the distance from the tip of the stator tooth 4 is 1.21%-6.05% of the height of the stator 1 pole.

[0029] Specifically, the torque ripple coefficient is (T1-T2) / T3=0.73; where T1 is the maximum torque value during stable operation of the motor, T2 is the minimum torque value during stable operation of the motor, and T3 is the average torque value during stable operation of the motor. The auxiliary slots inside the rotor tooth poles are located on the tooth ends of the rotor tooth 5 on the side where the rotor tooth 5 and stator tooth 4 preferentially contact each other; the auxiliary slots inside the stator tooth poles are located on the tooth ends of the stator tooth 4 on the side where the stator tooth 4 and rotor tooth 5 preferentially contact each other.

[0030] Furthermore, refer to Figure 5 As shown, the design utilizes the structural parameters of this wide rotor tooth 5-bearing-free switched reluctance motor. (Refer to...) Figure 2 As shown, through calculation of specific motor structural parameters, the side length of the square auxiliary slot 6 inside the stator tooth 4 pole ranges from 0.2mm to 1mm, and is taken as 0.7mm in this example; the distance from the stator tooth edge 8 ranges from 0.1mm to 1mm, and is taken as 0.4mm; the distance from the stator tooth tip 4 ranges from 0.2mm to 1mm, and is taken as 0.4mm. (Refer to...) Figure 3As shown, specific motor structural parameters are calculated. The length of the parallelogram auxiliary slot 7 inside the rotor tooth 5 pole ranges from 1mm to 2mm, and is taken as 2mm in this example; the height ranges from 1mm to 1.4mm, and is taken as 1.2mm; the distance from the rotor tooth edge 9 ranges from 0.15mm to 0.45mm, and is taken as 0.15mm; the distance from the rotor tooth tip 5 ranges from 0.1mm to 0.4mm, and is taken as 0.1mm.

[0031] Furthermore, such as Figure 6 The figure shows a comparison of the radial magnetic flux density of the original model and the improved model; the maximum radial magnetic flux density of the original model is 1.43T, while that of the improved model is 1.2T, a reduction of 16.1%. Figure 7 As shown, the maximum tangential magnetic flux density of the original model is 0.31T, while that of the improved model is 0.43T, an increase of 38.7%.

[0032] Figure 8 The diagram shown is a schematic representation of the original model's magnetic field lines. Figure 9 This is a schematic diagram of the magnetic field lines in the improved model.

[0033] It can be seen that adding the square auxiliary slot 6 can change the direction of the magnetic lines of force inside the stator tooth 4 pole, thereby increasing the tangential component of the magnetic lines of force and decreasing the radial component. Figure 10 The image shown is a simulation diagram of the magnetic field lines in the original model without the square auxiliary slot 6. Figure 11 The diagram shown is a simulation of the improved magnetic field line routing. In this example, the side length of the parallelogram auxiliary slot 7 inside the rotor tooth 5 pole ranges from 1 to 2 mm. Its influence on the average torque and torque ripple of the motor is as follows. Figure 12 , Figure 13 As shown, when the side length is 2mm, the average motor torque is the maximum and the torque ripple is the minimum. Therefore, this scheme selects a side length of 2mm for the parallelogram auxiliary slot 7. In this example, the height of the parallelogram auxiliary slot 7 inside the rotor tooth 5 pole ranges from 1 to 1.4mm, and its influence on the average motor torque and torque ripple is as follows. Figure 14 , Figure 15 As shown, when the height is 1.2mm, the average motor torque is the largest and the torque ripple is small. Therefore, this scheme selects a height of 1.2mm for the parallelogram auxiliary slot 7. In this example, the distance between the parallelogram auxiliary slot 7 inside the rotor tooth 5 pole and the rotor tooth edge 9 ranges from 0.15-0.45mm. Its influence on the average motor torque and torque ripple is as follows. Figure 16 , Figure 17As shown, when the distance is 0.15mm, the average motor torque is the maximum and the torque ripple is the minimum. Therefore, this scheme selects a distance of 0.15mm between the parallelogram auxiliary slot 7 and the rotor tooth edge 9. In this example, the distance between the parallelogram auxiliary slot 7 inside rotor tooth 5 and the tip of rotor tooth 5 ranges from 0.1-0.4mm, and its influence on the average motor torque and torque ripple is as follows. Figure 18 , Figure 19 As shown, when the distance is 0.1mm, the average motor torque is the maximum and the torque ripple is the minimum. Therefore, this scheme selects a distance of 0.1mm between the parallelogram auxiliary slot 7 and the tip of the rotor tooth 5. In this example, the side length of the square auxiliary slot 6 inside the stator tooth 4 pole ranges from 0.2-1mm, and its influence on the average motor torque and torque ripple is as follows. Figure 20 , Figure 21 As shown, when the side length is 0.7mm, the average motor torque is larger and the torque ripple is smaller. Therefore, this scheme selects a side length of 0.7mm for the square auxiliary slot 6. In this example, the distance between the square auxiliary slot 6 inside the stator tooth 4 pole and the stator tooth edge 8 ranges from 0.1-1mm. Its influence on the average motor torque and torque ripple is as follows. Figure 22 , Figure 23 As shown, when the distance is 0.4mm, the average motor torque is larger and the torque ripple is smaller. Therefore, this scheme selects a distance of 0.4mm between the square auxiliary slot 6 and the stator tooth edge 8. In this example, the distance between the square auxiliary slot 6 inside stator tooth 4 and the tip of stator tooth 4 ranges from 0.2-1mm, and its influence on the average motor torque and torque ripple is as follows. Figure 24 , Figure 25 As shown, when the distance is 0.4mm, the average torque of the motor is larger and the torque pulsation is smaller. Therefore, this scheme selects the distance between the square auxiliary slot 6 and the top of the stator tooth 4 as 0.4mm. Example

[0034] Based on Embodiment 1 or Embodiment 2; applicable to three-phase 12 / 8 pole switched reluctance motors or three-phase 12 / 8 pole bearingless switched reluctance motors; stator 1 adopts 12 sets of stator windings 3.

[0035] Specifically, such as Figures 1-3 As shown, a bearingless switched reluctance motor with a toothed structure includes: a double salient pole stator and rotor 2, including a rotor 2, and a stator 1 and 12 sets of stator windings 3 sleeved around the rotor 2. Both the stator 1 and the rotor 2 are salient pole structures. The stator 1 is provided with several sets of stator teeth 4 extending towards the rotor 2; the rotor 2 is provided with several sets of rotor teeth 5 extending outward; and several sets of stator windings 3 are wound on the stator teeth 4.

[0036] The stator tooth 4 has an internal auxiliary slot on its inner side; the internal auxiliary slot of the stator tooth is a square auxiliary slot 6. The rotor 2 rotates counterclockwise when the motor is running; the rotor tooth edge 9 is the edge of the rotor tooth 5 in the contact direction between the stator tooth 4 and the rotor tooth 5 when the motor rotor 2 rotates; the side length of the internal auxiliary slot of the rotor tooth is 14.3%-28.6% of the height of the rotor 2 pole, the height is 7.75%-10.85% of the width of the rotor 2 pole, the distance from the rotor tooth edge 9 is 1.16%-3.48% of the width of the rotor 2 pole, and the distance from the tip of the rotor tooth 5 is 1.43%-5.73% of the height of the rotor 2 pole.

[0037] The rotor teeth 5 of rotor 2 are provided with auxiliary slots inside the rotor tooth poles. The auxiliary slots inside the rotor tooth poles are parallelogram auxiliary slots 7. The rotor 2 rotates in the counterclockwise direction when the motor is running; the stator tooth edge 8 is the edge of the stator tooth 4 in the contact direction between the stator tooth 4 and the rotor tooth 5 when the motor rotor 2 rotates; the side length of the auxiliary slot inside the stator tooth pole is 3.03%-15.15% of the width of the stator 1 pole, the distance from the stator tooth edge 8 is 1.51%-15.1% of the width of the stator 1 pole, and the distance from the tip of the stator tooth 4 is 1.21%-6.05% of the height of the stator 1 pole.

[0038] Specifically, the torque ripple coefficient is (T1-T2) / T3=0.73; where T1 is the maximum torque value when the motor is running stably, T2 is the minimum torque value when the motor is running stably, and T3 is the average torque value when the motor is running stably.

[0039] The auxiliary groove inside the rotor tooth pole is set on the tooth end of the rotor tooth 5 on the side where the rotor tooth 5 and the stator tooth 4 first contact; the auxiliary groove inside the stator tooth pole is set on the tooth end of the stator tooth 4 on the side where the stator tooth 4 and the rotor tooth 5 first contact. Example

[0040] Based on Embodiment 1 or Embodiment 2; applicable to three-phase 12 / 8 pole switched reluctance motors or three-phase 12 / 8 pole bearingless switched reluctance motors; stator 1 adopts 12 sets of stator windings 3.

[0041] Specifically, such as Figures 1-3 As shown, a bearingless switched reluctance motor with a toothed structure includes: a double salient pole stator and rotor 2, including a rotor 2, and a stator 1 and 12 sets of stator windings 3 sleeved around the rotor 2. Both the stator 1 and the rotor 2 are salient pole structures. The stator 1 is provided with several sets of stator teeth 4 extending towards the rotor 2; the rotor 2 is provided with several sets of rotor teeth 5 extending outward; and several sets of stator windings 3 are wound on the stator teeth 4.

[0042] The stator tooth 4 has an internal auxiliary slot on its inner side; the internal auxiliary slot of the stator tooth is a square auxiliary slot 6. The rotor 2 rotates counterclockwise when the motor is running; the rotor tooth edge 9 is the edge of the rotor tooth 5 in the contact direction between the stator tooth 4 and the rotor tooth 5 when the motor rotor 2 rotates; the side length of the internal auxiliary slot of the rotor tooth is 14.3%-28.6% of the height of the rotor 2 pole, the height is 7.75%-10.85% of the width of the rotor 2 pole, the distance from the rotor tooth edge 9 is 1.16%-3.48% of the width of the rotor 2 pole, and the distance from the tip of the rotor tooth 5 is 1.43%-5.73% of the height of the rotor 2 pole.

[0043] The rotor teeth 5 of rotor 2 are provided with auxiliary slots inside the rotor tooth poles. The auxiliary slots inside the rotor tooth poles are parallelogram auxiliary slots 7. The rotor 2 rotates in the counterclockwise direction when the motor is running; the stator tooth edge 8 is the edge of the stator tooth 4 in the contact direction between the stator tooth 4 and the rotor tooth 5 when the motor rotor 2 rotates; the side length of the auxiliary slot inside the stator tooth pole is 3.03%-15.15% of the width of the stator 1 pole, the distance from the stator tooth edge 8 is 1.51%-15.1% of the width of the stator 1 pole, and the distance from the tip of the stator tooth 4 is 1.21%-6.05% of the height of the stator 1 pole.

[0044] Specifically, the torque ripple coefficient is (T1-T2) / T3=0.73; where T1 is the maximum torque value when the motor is running stably, T2 is the minimum torque value when the motor is running stably, and T3 is the average torque value when the motor is running stably.

[0045] The auxiliary groove inside the rotor tooth pole is set on the tooth end of the rotor tooth 5 on the side where the rotor tooth 5 and the stator tooth 4 first contact; the auxiliary groove inside the stator tooth pole is set on the tooth end of the stator tooth 4 on the side where the stator tooth 4 and the rotor tooth 5 first contact. Example

[0046] Based on Embodiment 1, Embodiment 2, Embodiment 3, or Embodiment 4; a method for changing the average torque of a motor, using a bearingless switched reluctance motor with a toothed structure, includes the following: enhancing the average torque of the motor by changing the structural form of the motor stator 1 and rotor 2, and significantly reducing the motor torque pulsation.

[0047] The rotor teeth 5 have parallelogram auxiliary slots 7 inside, and the stator teeth 4 have square auxiliary slots 6 inside. These can increase the magnetic resistance in the magnetic circuit, change the direction of the magnetic lines of force, thereby weakening the radial magnetic flux density in the air gap and increasing the tangential magnetic flux density, thus increasing the average torque and significantly reducing torque pulsation.

[0048] Magnetic flux always closes along the path of least magnetic resistance. The parallelogram auxiliary slot 7 is opened inside the rotor tooth 5 pole, which can increase the magnetic resistance in the magnetic circuit and change the direction of the magnetic lines of force. This allows the magnetic lines of force to enter the rotor 2 through the magnetic circuit between the parallelogram auxiliary slot 7 and the tip of the rotor tooth 5, thereby changing the angle at which the magnetic flux enters the rotor tooth 5. This reduces the radial magnetic flux density in the air gap and increases the tangential magnetic flux density, thereby increasing the average torque and reducing the inherent torque pulsation.

[0049] A square auxiliary slot 6 is opened inside the tooth pole of stator tooth 4, which increases the magnetic resistance in the magnetic circuit and changes the direction of the magnetic lines of force. When the magnetic lines of force pass through the square auxiliary slot 6 and rotate with the motor rotor 2, the magnetic circuit between the stator tooth edge 8 in the contact direction of stator and rotor teeth 5 is compressed, and enters rotor tooth 5 through the non-overlapping area of ​​stator and rotor teeth 5. The radial force generated in the overlapping area of ​​stator and rotor teeth 5 is the effective radial force, and the radial component of the magnetic lines of force in the non-overlapping area of ​​stator and rotor teeth 5 is an ineffective component. The tangential force is generated at the edge of the two overlapping areas, and the tangential component in that part is an effective component. Ultimately, this can further reduce torque pulsation.

[0050] Working principle: like Figures 1-25 As shown, the bearingless switched reluctance motor with a toothed structure in this invention takes a 12 / 8 wide rotor tooth 5-axis bearingless switched reluctance motor as an example. By changing the structural form of the stator 1 and rotor 2, the average torque of the motor is enhanced, the torque ripple is significantly reduced, and the motor performance is improved. The structure and working principle of the wide rotor tooth 5-axis bearingless switched reluctance motor are relatively simple. The mechanical angle of its rotor tooth 5 is increased from 15° in the traditional bearingless switched reluctance motor to 30°. This change solves the coupling problem of torque and levitation force in the traditional BSRM. However, the doubly salient pole structure and the switching power supply of the motor are not changed, resulting in the inherent torque ripple still existing. The existence of torque ripple will affect the smooth operation of the motor, aggravate the vibration of the motor, thereby accelerating the wear of components such as the motor shaft and reducing the service life of worn components, which will affect the widespread use of bearingless switched reluctance motors. The rotor teeth 5 of the present invention have parallelogram auxiliary slots 7 inside, and the stator teeth 4 have square auxiliary slots 6 inside. These can increase the magnetic resistance in the magnetic circuit, change the direction of the magnetic lines of force, thereby weakening the radial magnetic flux density in the air gap and increasing the tangential magnetic flux density, so as to increase the average torque and significantly reduce the torque pulsation.

[0051] More specifically, based on the principle of minimum magnetic reluctance of BSRMWR, that is, magnetic flux always closes along the path of minimum magnetic reluctance, a parallelogram auxiliary slot 7 is opened inside the tooth pole of rotor tooth 5. This can increase the magnetic reluctance in the magnetic circuit and change the direction of the magnetic lines of force. The magnetic lines of force enter the rotor 2 through the magnetic circuit between the parallelogram auxiliary slot 7 and the tooth tip of rotor tooth 5, thereby changing the angle at which the magnetic flux enters rotor tooth 5. This reduces the radial magnetic flux density in the air gap and increases the tangential magnetic flux density, thereby increasing the average torque of BSRMWR and reducing the inherent torque pulsation.

[0052] A square auxiliary slot 6 is opened inside the tooth pole of stator tooth 4, which increases the magnetic resistance in the magnetic circuit and changes the direction of the magnetic field lines. When the magnetic field lines pass through the square auxiliary slot 6 and rotate with the motor rotor 2, the magnetic circuit between the stator tooth edges 8 in the contact direction of the stator and rotor teeth 5 is compressed, and some of the magnetic field lines enter the rotor teeth 5 through the non-overlapping area of ​​the stator and rotor teeth 5. Since only the radial force generated in the overlapping area of ​​the stator and rotor teeth 5 is an effective radial force, the radial component of the magnetic field lines in the non-overlapping area of ​​the stator and rotor teeth 5 is an ineffective component. The tangential force is generated at the edge of the two overlapping areas, so the tangential component in this part is an effective component, which can ultimately achieve the purpose of further reducing torque pulsation.

[0053] Simulation tests were conducted using current chopper control to apply the same current to both a BSRMWR employing the novel tooth profile structure of this invention and a conventional BSRMWR. While existing improvements can reduce torque ripple, they do not consider the average torque of the motor, and may even reduce it. This proposed solution increases the minimum resultant torque, significantly reducing motor torque ripple while simultaneously improving the average torque of the motor. Figure 4 This chart compares the output torque of a BSRMWR using the novel tooth structure of this invention and a conventional BSRMWR during steady-state operation. During steady-state motor operation, the average output torque of the BSRMWR using the novel tooth structure is 0.802 Nm, while the average output torque of the conventional BSRMWR is 0.762 Nm, representing a 5.25% increase in average torque. Based on the torque ripple coefficient calculation formula: (maximum torque value during stable motor operation - minimum torque value during stable motor operation) / average torque value during stable motor operation, we can obtain that the torque ripple coefficient of the BSRMWR using the novel tooth structure is 0.73, while the torque ripple coefficient of the conventional BSRMWR is 1.22, representing a 40.2% reduction in torque ripple coefficient. The calculation results show that the BSRMWR with the novel tooth structure of this invention can achieve the goal of increasing average torque and significantly reducing torque ripple.

[0054] Based on the preferred embodiments of the present invention described above, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A bearingless switched reluctance motor with a toothed structure, characterized in that, Includes: a double salient pole stator and rotor, wherein the double salient pole stator and rotor include a rotor and a stator sleeved around the rotor; The stator is provided with several sets of stator teeth that extend toward the rotor; The rotor is provided with several sets of outwardly extending rotor teeth; The stator teeth are wound with several sets of stator windings; The stator teeth are provided with an internal auxiliary groove for the stator tooth pole on the inner side; The rotor teeth are provided with auxiliary grooves inside the rotor tooth poles. The auxiliary slots inside the rotor tooth poles are parallelogram-shaped; the auxiliary slots inside the stator tooth poles are square-shaped. The rotor rotation direction during motor operation is counterclockwise; the stator tooth edge is the stator tooth edge in the contact direction between the stator teeth and the rotor teeth when the motor rotor rotates. The rotor rotation direction during motor operation is counterclockwise; The rotor tooth edge is the edge of the rotor tooth in the contact direction between the stator tooth and the rotor tooth when the motor rotor rotates; The side length of the auxiliary slot inside the rotor tooth pole is 28.6% of the height of the rotor pole, the height is 9.3% of the width of the rotor pole, the distance from the edge of the rotor tooth is 1.16% of the width of the rotor pole, and the distance from the tip of the rotor tooth is 1.43% of the height of the rotor pole. The stator tooth edge is the stator tooth edge in the contact direction between the stator teeth and the rotor teeth when the motor rotor rotates; The side length of the auxiliary groove inside the stator tooth pole is 10.61% of the stator pole width, the distance from the stator tooth edge is 6.04% of the stator pole width, and the distance from the stator tooth tip is 2.42% of the stator pole height.

2. The bearingless switched reluctance motor with a toothed structure according to claim 1, characterized in that: It is applicable to three-phase 12 / 8-pole switched reluctance motors or three-phase 12 / 8-pole bearingless switched reluctance motors; the stator adopts 12 sets of stator windings.

3. The bearingless switched reluctance motor with a toothed structure according to claim 2, characterized in that: The torque ripple coefficient is: (T1-T2) / T3=0.73; where T1 is the maximum torque value when the motor is running stably, T2 is the minimum torque value when the motor is running stably, and T3 is the average torque value when the motor is running stably.

4. The bearingless switched reluctance motor with a toothed structure according to claim 3, characterized in that: The auxiliary groove inside the rotor tooth pole is provided on the tooth tip of the rotor tooth on the side where the rotor tooth and stator tooth preferentially contact each other. The auxiliary groove inside the stator tooth pole is provided on the tooth tip of the stator tooth on the side where the stator tooth and rotor tooth make preferential contact.

5. A method for changing the average torque of a motor, characterized in that, A bearingless switched reluctance motor employing the toothed structure described in any one of claims 1-4; comprising the following: By changing the structure of the motor stator and rotor, the average torque of the motor can be enhanced, and the torque ripple of the motor can be significantly reduced.

6. The method for changing the average torque of a motor according to claim 5, characterized in that: The rotor teeth have parallelogram auxiliary slots inside, and the stator teeth have square auxiliary slots inside. These can increase the magnetic resistance in the magnetic circuit, change the direction of the magnetic lines of force, thereby weakening the radial magnetic flux density in the air gap and increasing the tangential magnetic flux density, thus increasing the average torque and significantly reducing torque pulsation. Magnetic flux always closes along the path of least magnetic resistance. By opening parallelogram auxiliary slots inside the rotor tooth poles, the magnetic resistance in the magnetic circuit can be increased, and the direction of the magnetic lines of force can be changed. This allows the magnetic lines of force to enter the rotor through the magnetic circuit between the parallelogram auxiliary slots and the rotor tooth tips, thereby changing the angle at which the magnetic flux enters the rotor teeth. This reduces the radial magnetic flux density in the air gap and increases the tangential magnetic flux density, thereby increasing the average torque and reducing the inherent torque pulsation. A square auxiliary slot is opened inside the stator tooth pole, which increases the magnetic resistance in the magnetic circuit and changes the direction of the magnetic lines of force. When the magnetic lines of force pass through the square auxiliary slot and rotate with the motor rotor, the magnetic circuit between the stator tooth edges in the stator and rotor tooth contact direction is compressed, and some magnetic lines of force enter the rotor tooth through the non-overlapping area of ​​the stator and rotor teeth. The radial force generated in the overlapping area of ​​the stator and rotor teeth is the effective radial force. The radial component of the magnetic field lines in the non-overlapping area of ​​the stator and rotor teeth is an ineffective component. The tangential force is generated at the edge of the two overlapping areas, and the tangential component of that part is an effective component. Ultimately, this can further reduce torque pulsation.

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