A demagnetization-resistant motor rotor

Abstract

The application relates to a demagnetization-resistant motor rotor, which comprises a motor stator; the inner wall of the motor stator is circumferentially provided with a stator core; and the middle part of the motor stator is provided with a rotor structure. The demagnetization-resistant motor rotor is provided with a permanent magnet structure, wherein the first magnet slot and the second permanent magnet slot are in V-shaped structures, have a magnetic concentration effect, and are additionally provided with auxiliary slots, so that the magnetic field distribution is more uniform and reasonable, thereby improving the performance of the motor; the second magnetic separation slot is additionally provided, so that the magnetic field distribution of the motor is more reasonable and uniform, the magnetic circuit efficiency is improved, the output performance of the motor is improved, the bypass magnetic circuit is additionally provided to improve the running direction of the magnetic lines, thereby reducing the local demagnetization risk of the permanent magnet, improving the performance and reliability of the motor, the first magnetic separation slot is additionally provided to reduce the magnetic field intensity of the part of the permanent magnet with the maximum demagnetization risk, thereby reducing the probability of the demagnetization risk of the permanent magnet, and the demagnetization resistance of the motor is improved without increasing the thickness of the permanent magnet.

Description

Technical Field

[0001] This invention relates to the field of high-efficiency and energy-saving electric motor technology, specifically to an anti-demagnetizing motor rotor. Background Technology

[0002] Step-start permanent magnet motors are high-efficiency and energy-saving motors. The characteristic of step-start permanent magnet motors is that they can be directly started by power frequency without the need for a frequency converter, which can improve the simplicity of the transmission system, reduce costs, improve the cost performance of the motor, and make it more acceptable to users.

[0003] The two main factors causing irreversible demagnetization of permanent magnets in permanent magnet motors are the reverse demagnetizing field and high temperature. During the operation of a permanent magnet synchronous motor, occasional operation under demagnetizing conditions is unavoidable. This will lead to decreased motor performance, increased losses, severe temperature rise, and even motor shutdown. Therefore, optimizing permanent magnet motors to resist demagnetization is very important.

[0004] Rotor optimization designs to improve the demagnetization resistance of permanent magnets often involve increasing the thickness of the permanent magnets to enhance the motor's demagnetization resistance. This approach directly leads to a significant increase in the manufacturing cost of permanent magnet synchronous motors. Summary of the Invention

[0005] (0) Technical problems to be solved To solve the above-mentioned technical problems, the present invention provides a motor rotor that is resistant to demagnetization.

[0006] (II) Technical Solution Based on this, the present invention provides the following technical solution: a demagnetizing motor rotor, comprising a motor stator; a stator core is circumferentially distributed on the inner wall of the motor stator, a rotor structure is provided in the middle of the motor stator, and a permanent magnet structure is circumferentially distributed on the inner side of the rotor structure; the permanent magnet structure includes a permanent magnet slot one, a bypass magnetic circuit, a magnetic isolation slot one, a permanent magnet, a magnetic isolation slot two, and a permanent magnet slot two; the permanent magnet slot one is opened on the inner side of the rotor structure, a bypass magnetic circuit is provided on the left side of the permanent magnet slot one, a magnetic isolation slot one is provided at the upper left end of the permanent magnet slot one, a permanent magnet is embedded in the middle of the permanent magnet slot one, a magnetic isolation slot two is opened on the right side of the permanent magnet slot one, and a permanent magnet slot two is provided at the lower end of the permanent magnet slot one.

[0007] Preferably, the permanent magnet slot one, the bypass magnetic circuit, the magnetic isolation slot one, and the permanent magnet together constitute an anti-demagnetization structure. There are two sets of anti-demagnetization structures, which are arranged opposite each other along the left and right sides of the magnetic isolation slot two, and the two sets of permanent magnet slot one form a V-shaped structure.

[0008] Preferably, the structure of the first permanent magnet slot is the same as that of the second permanent magnet slot, and the first permanent magnet slot and the second permanent magnet slot are arranged in parallel to each other. The second permanent magnet slot is equipped with a bypass magnetic circuit, a magnetic isolation slot one, a permanent magnet, and a magnetic isolation slot two.

[0009] Preferably, both the magnet slot one and the permanent magnet slot two are inclined at an angle of 18°.

[0010] Preferably, when the permanent magnet is disposed inside the permanent magnet slot, there are auxiliary slots on the left and right sides of the permanent magnet slot, and the depth of the auxiliary slots is 0.5mm.

[0011] Preferably, the second magnetic shielding groove has a length of 5.5 mm and a width of 2 mm.

[0012] Preferably, the bypass magnetic circuit is arranged in multiple segments, and multiple sets of inner grooves are provided on the bypass magnetic circuit. The thickness and spacing of each inner groove are 0.5 mm, and the length of the inner groove is 1.5 mm.

[0013] Preferably, the magnetic isolation groove is located at the corner of the outer layer of the permanent magnet, and the width of the magnetic isolation groove is 0.6mm.

[0014] Preferably, the thickness of the first permanent magnet groove is the same as the thickness of the second permanent magnet groove, and the thickness of the first permanent magnet groove is t. b1 The thickness of the permanent magnet groove 46 is t. b2 The inner diameter of the rotor structure is D. r The outer diameter of the rotor structure is D. sh The expression for the permanent magnet content is: .

[0015] (III) Beneficial Effects Compared with the prior art, the present invention provides a motor rotor that is resistant to demagnetization, which has the following beneficial effects: This demagnetizing motor rotor incorporates a permanent magnet structure. Firstly, magnet slot one and permanent magnet slot two form a V-shaped structure, providing a magnetizing effect. Secondly, auxiliary slots are added to make the magnetic field distribution more uniform and rational, thereby improving motor performance. Thirdly, the addition of magnetic isolation slot two further optimizes the magnetic field distribution, improving magnetic circuit efficiency and output performance. Fourthly, the addition of a bypass magnetic circuit improves the direction of magnetic lines of force, reducing the risk of localized demagnetization of the permanent magnets and enhancing motor performance and reliability. Finally, the addition of magnetic isolation slot one reduces the magnetic field strength of the portion of the permanent magnet most susceptible to demagnetization, thus lowering the probability of demagnetization. All of these improvements enhance the motor's demagnetization resistance without increasing the thickness of the permanent magnets. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a partial cross-sectional structural diagram of the present invention; Figure 3 This is a schematic cross-sectional view of the permanent magnet structure of the present invention; Figure 4 This is a schematic diagram showing the demagnetization rate of the permanent magnet under different temperatures and currents according to the present invention. Figure 5 This is a schematic diagram showing the demagnetization rate of permanent magnets with magnetically insulating grooves of different lengths according to the present invention. Figure 6 This is a schematic diagram showing the demagnetization rate of permanent magnets with different lengths of bypass magnetic circuits according to the present invention. Figure 7 This is a schematic diagram showing the demagnetization rate of permanent magnets with different widths of magnetic isolation grooves according to the present invention; Figure 8 This is a schematic diagram of the electromagnetic torque and reluctance torque of the motor of the present invention.

[0017] In the diagram: motor stator-1, stator core-2, rotor structure-3, permanent magnet structure-4, permanent magnet slot 1-41, bypass magnetic circuit-42, magnetic isolation slot 1-43, permanent magnet-44, magnetic isolation slot 2-45, permanent magnet slot 2-46. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Please see Figures 1-2 An anti-demagnetizing motor rotor includes a motor stator 1; a stator core 2 is circumferentially distributed on the inner wall of the motor stator 1, a rotor structure 3 is provided in the middle of the motor stator 1, and a permanent magnet structure 4 is circumferentially distributed on the inner side of the rotor structure 3.

[0020] Please see Figure 3A demagnetizing motor rotor, the permanent magnet structure 4 includes a permanent magnet slot 41, a bypass magnetic circuit 42, a magnetic isolation slot 43, a permanent magnet 44, a magnetic isolation slot 45, and a permanent magnet slot 46. The permanent magnet slot 41 is located inside the rotor structure 3. The bypass magnetic circuit 42 is located on the left side of the permanent magnet slot 41. The magnetic isolation slot 43 is located at the upper left end of the permanent magnet slot 41. The permanent magnet 44 is embedded in the middle of the permanent magnet slot 41. The magnetic isolation slot 45 is located on the right side of the permanent magnet slot 41. The permanent magnet slot 44 is located at the lower end of the permanent magnet slot 41. The second type of magnet slot 46, the first type of permanent magnet slot 41, the bypass magnetic circuit 42, the first type of magnetic isolation slot 43, and the permanent magnet 44 together constitute an anti-demagnetization structure. There are two sets of anti-demagnetization structures, which are arranged opposite each other on the left and right sides of the second type of magnetic isolation slot 45. The two sets of the first type of permanent magnet slot 41 form a V-shaped structure. The structure of the first type of permanent magnet slot 41 is the same as that of the second type of permanent magnet slot 46. The first type of permanent magnet slot 41 and the second type of permanent magnet slot 46 are arranged in parallel. The second type of permanent magnet slot 46 is equipped with the bypass magnetic circuit 42, the first type of magnetic isolation slot 43, the permanent magnet 44, and the second type of magnetic isolation slot 45.

[0021] In some embodiments, both magnet slot 1 41 and permanent magnet slot 2 46 are inclined at an 18° angle, and the V-shaped structure has a magnetizing effect.

[0022] In some embodiments, when the permanent magnet 44 is disposed inside the permanent magnet slot 41, auxiliary slots exist on the left and right sides of the permanent magnet slot 41, and the depth of the auxiliary slots is 0.5mm. Two-dimensional models are established using finite element software, and the motor model is as follows: Figure 3 As shown, auxiliary slots can effectively improve the demagnetization resistance of motors. In the motor model, auxiliary slots make the magnetic field distribution more uniform and reasonable, thereby improving motor performance. If the auxiliary slots are set too deep, it may lead to excessive stress on the rotor structure, affecting the service life of the motor. If they are set too shallow, the optimization effect is not obvious and the expected improvement effect cannot be achieved. Therefore, parametric simulation of the depth of the auxiliary slots is performed, and the motor is placed under extreme working conditions of temperature and external magnetic field to analyze the influence of auxiliary slots of different depths on the motor's demagnetization resistance. Figure 4 As shown. From Figure 4 As can be seen, when the auxiliary groove is set to a depth of 0.1mm and 0.3mm, it is too shallow and has not achieved the best anti-demagnetization ability, while the depth of 0.7mm is too deep and increases the demagnetization rate of the permanent magnet. Therefore, setting the rotor auxiliary groove to 0.5mm is a relatively reasonable choice.

[0023] In some embodiments, the second magnetic isolation slot 45 has a length of 5.5 mm and a width of 2 mm. Adding the second magnetic isolation slot 45 effectively reduces motor leakage flux, thereby improving motor performance. In the motor model, adding the second magnetic isolation slot 45 makes the magnetic field distribution of the motor more reasonable and uniform, improving magnetic circuit efficiency and motor output performance. However, in the process of adding the intermediate magnetic isolation slot, the mechanical strength of the rotor, especially the stress on the intermediate magnetic bridge, needs to be considered. Therefore, while retaining a 1 mm thick intermediate magnetic bridge, parametric simulations were performed on the length of the second magnetic isolation slot 45, and the motor was placed under extreme operating conditions to analyze the effect of different sizes of intermediate magnetic isolation slots on motor demagnetization. Figure 5 As shown in the figure, the demagnetization rate of the permanent magnet is lowest when the length of the intermediate magnetic slot is set to 5.5mm. Therefore, a width of 2mm and a length of 5.5mm are selected for the intermediate magnetic slot, with each magnetic bridge on both sides of the slot being 0.5mm wide. This effectively balances the motor's performance and mechanical strength, ensuring stable and reliable operation during use.

[0024] In some embodiments, the bypass magnetic circuit 42 is arranged in multiple segments, with multiple sets of inner grooves on the bypass magnetic circuit 42. The thickness and spacing of each inner groove are 0.5 mm, and the length of the inner groove is 1.5 mm. During motor operation, the permanent magnet 44 is prone to demagnetization near the corners of the air gap, which leads to a greater risk of demagnetization at the corners. To solve this problem, the direction of the magnetic field lines can be improved by adding the bypass magnetic circuit 42, thereby reducing the risk of local demagnetization of the permanent magnet and improving the performance and reliability of the motor. In the motor model, the number of segments, position, thickness, and length of the bypass magnetic circuit 42 will all have different effects on the demagnetization resistance of the permanent magnet 44. If the bypass magnetic circuit is positioned too close to the permanent magnet 44, it may collide with the permanent magnet due to deformation caused by the high-speed rotation of the rotor, thus affecting the motor's performance and lifespan, and even posing a risk of motor damage and personal safety. Furthermore, the space available for the bypass magnetic circuit 42 is limited, and the number should not be too small. Therefore, it is advisable to set three bypass magnetic circuit segments within the permanent magnet slot, each with a thickness and spacing of 0.5mm. In addition, the length of the bypass magnetic circuit 42 is parameterized, and the motor is placed under extreme operating conditions to analyze the impact of different bypass magnetic circuit lengths on the motor's demagnetization resistance. Figure 6As shown in the figure, lengths of 1.0mm and 1.25mm did not achieve the optimal demagnetization resistance, while a length of 1.75mm, due to the excessive length of the bypass magnetic circuit 42, caused the magnetic lines of force guided by it to converge again at the edge of the permanent magnet 44, resulting in a large demagnetization field and an increase in the demagnetization rate instead of a decrease. Therefore, the length of the bypass magnetic circuit 42 was ultimately set to 1.5mm. This maximizes the demagnetization resistance of the permanent magnet while ensuring motor performance and reliability, thus ensuring stable motor operation.

[0025] In some embodiments, the magnetic isolation groove 43 is disposed at the corner of the outer layer of the permanent magnet 44. The width of the magnetic isolation groove 43 is 0.6mm. It can effectively reduce the magnetic field strength of the part of the permanent magnet 44 that is most at risk of demagnetization, thereby reducing the probability of demagnetization of the permanent magnet 44. If the magnetic isolation groove 43 is too large, it will reduce the magnetic energy density of the permanent magnet 44 and affect the output performance of the motor. If it is too close to the outer side, the permanent magnet 44 at the corner will be subjected to a larger demagnetizing magnetic field, making the permanent magnet 44 more prone to local demagnetization. If it is too small or too close to the inner side, the effect of the magnetic isolation groove 43 may not be significant. Therefore, the center of the magnetic isolation groove 43 is set at the point of highest demagnetization rate and extends to both sides until it is 1.5mm away from the outermost corner of the permanent magnet 44. At this time, the length of the magnetic isolation groove 43 is 4mm. An improper setting of the width of the magnetic isolation slot 43 will also affect the demagnetization resistance of the permanent magnet. Therefore, the width of the magnetic isolation slot is parameterized, and the motor is placed under extreme operating conditions to analyze the influence of magnetic isolation slots of different widths on the motor's demagnetization resistance. Figure 7 As shown in the figure, the 0.3mm and 0.4mm wide magnetic isolation groove 43 did not achieve the optimal demagnetization effect. However, when the width was set to 0.6mm, the magnetic isolation groove 43 became too large, resulting in a high demagnetization field near it and an increase in the demagnetization rate of the permanent magnet. Therefore, setting the width of the magnetic isolation groove 43 to 0.5mm was ultimately more appropriate.

[0026] In some embodiments, the thickness of permanent magnet groove 41 is the same as the thickness of permanent magnet groove 46, and the thickness of permanent magnet groove 41 is t. b1 The thickness of permanent magnet slot 246 is t. b2 The inner diameter of rotor structure 3 is D. r The outer diameter of rotor structure 3 is D. sh The expression for the permanent magnet content is: ,like Figure 8 As shown, simulations were used to compare different permanent magnet content rates, i.e., K. air Under a given value, the electromagnetic torque and reluctance torque of the motor are... The electromagnetic torque and reluctance torque vary with K... air As the value increases, the reluctance torque increases in K. airIt reaches its maximum value of 188 N·m when the value is 0.35. The magnetic barrier width remains constant, K... air A larger value means more permanent magnets are used, leading to a stronger air gap magnetic field and a greater electromagnetic torque output by the motor. Simultaneously, K... air As the value increases, the width of the magnetic barrier in the direct axis increases, leading to an increase in the direct-axis component of the rotor inductance and a greater reluctance torque. However, K... air Once the value exceeds 0.35, the reluctance torque no longer increases. The minimum value is used as the criterion, K... air The value is set to 0.35, from which the thickness of permanent magnet groove 41 and permanent magnet groove 46 can be obtained.

[0027] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A demagnetizing motor rotor, characterized in that: Including the motor stator (1); The inner wall of the motor stator (1) is circumferentially distributed with stator cores (2), and the middle part of the motor stator (1) is provided with a rotor structure (3), and the inner side of the rotor structure (3) is circumferentially distributed with permanent magnet structures (4). The permanent magnet structure (4) includes a permanent magnet slot 1 (41), a bypass magnetic circuit (42), a magnetic isolation slot 1 (43), a permanent magnet (44), a magnetic isolation slot 2 (45), and a permanent magnet slot 2 (46). The permanent magnet slot 1 (41) is located inside the rotor structure (3). A bypass magnetic circuit (42) is provided on the left side of the permanent magnet slot 1 (41). A magnetic isolation slot 1 (43) is provided at the upper left end of the permanent magnet slot 1 (41). A permanent magnet (44) is embedded in the middle of the permanent magnet slot 1 (41). A magnetic isolation slot 2 (45) is provided on the right side of the permanent magnet slot 1 (41). A permanent magnet slot 2 (46) is provided at the lower end of the permanent magnet slot 1 (41). The permanent magnet slot 1 (41), bypass magnetic circuit (42), magnetic isolation slot 1 (43), and permanent magnet (44) form an anti-demagnetization structure. There are two sets of anti-demagnetization structures, which are arranged opposite to each other on the left and right sides of the magnetic isolation slot 2 (45), and the two sets of permanent magnet slot 1 (41) form a V-shaped structure. The structure of the permanent magnet slot 1 (41) is the same as that of the permanent magnet slot 2 (46), and the permanent magnet slot 1 (41) and the permanent magnet slot 2 (46) are arranged in parallel to each other. The permanent magnet slot 2 (46) is equipped with a bypass magnetic circuit (42), a magnetic isolation slot 1 (43), a permanent magnet (44), and a magnetic isolation slot 2 (45). The bypass magnetic circuit (42) is arranged in multiple segments, and multiple sets of inner grooves are provided on the bypass magnetic circuit (42). The thickness and spacing of each inner groove are 0.5mm, and the length of the inner groove is 1.5mm. The magnetic isolation groove 1 (43) is located at the corner of the outer layer of the permanent magnet (44). The width of the magnetic isolation groove 1 (43) is 0.6mm. The magnetic isolation groove 1 (43) extends to both sides of the permanent magnet (44). The length of the magnetic isolation groove 1 (43) is 4mm. The thickness of the first permanent magnet slot (41) is the same as the thickness of the second permanent magnet slot (46), and the thickness of the first permanent magnet slot (41) is t. b1 The thickness of the permanent magnet groove 2 (46) is t. b2 The inner diameter of rotor structure (3) is D. r The outer diameter of rotor structure (3) is D. sh The expression for the permanent magnet content is: k air The value is 0.

35.

2. The anti-demagnetizing motor rotor according to claim 1, characterized in that: Both permanent magnet slot one (41) and permanent magnet slot two (46) are inclined at an angle of 18°.

3. The anti-demagnetizing motor rotor according to claim 1, characterized in that: When the permanent magnet (44) is placed inside the permanent magnet slot (41), there are auxiliary slots on the left and right sides of the permanent magnet slot (41), and the depth of the auxiliary slots is 0.5mm.

4. The anti-demagnetizing motor rotor according to claim 1, characterized in that: The second magnetic isolation groove (45) has a length of 5.5 mm and a width of 2 mm.

Images