Motor rotor structure, assembly method and motor with magnetic focusing effect

Abstract

This invention discloses a motor rotor structure, assembly method, and motor with a magnetic focusing effect, belonging to the field of permanent magnet synchronous motors. The rotor structure includes a rotor core and a Halebeck magnet array. The Halebeck magnet array includes circumferentially magnetized magnets and radially magnetized magnets alternately distributed along the circumference. The radial thickness of the radially magnetized magnets is greater than that of the circumferentially magnetized magnets, causing rotor core bosses to form at each circumferentially magnetized magnet location. The radially magnetized magnets are divided into N magnet blocks along the circumference, with the radial thickness of the side blocks gradually increasing from the outer edge to the inner edge. Preferably, the two sides of the radially magnetized magnets are recessed towards the center block, forming a "V" shape, and the apex of the "V" shape is the intersection of the outer edge of the side block, the circumferentially magnetized magnets, and the rotor core bosses. This invention can utilize the magnetic focusing effect of the Halebeck permanent magnet array while solving the problems of high assembly difficulty, severe demagnetization, and low overload performance of the Halebeck permanent magnet array.

Description

Technical Field

[0001] This invention belongs to the field of permanent magnet synchronous motors, and more specifically, relates to a motor rotor structure with a magnetic focusing effect, an assembly method, and a motor. Background Technology

[0002] Replacing traditional internal combustion engines with distributed electric propulsion offers advantages such as lightweight structure, high integration, high efficiency, and low noise. It also significantly improves system safety redundancy, aircraft starting efficiency, and payload capacity, making it a crucial technological means for aviation electrification. The electric drive system is the core power equipment for all-electric aircraft during takeoff, landing, and cruise flight; its performance directly determines the aircraft's quality and pilot experience. Considering the aerospace industry's high sensitivity to weight and volume, and the different requirements placed on the electric drive system during takeoff, cruise, and landing, high power density, high torque density, high efficiency, high reliability, and high overload performance are simultaneously demanded. Finding greater torque density and stronger overload performance based on traditional permanent magnet motor topologies is the key and challenging aspect of designing such aviation electric drive systems.

[0003] Permanent magnet synchronous motors (PMSMs), with their high power density and efficiency, are the preferred motor type for propulsion systems in aerospace electric drives. Halbach permanent magnet arrays possess a magnetic focusing effect, increasing the air gap magnetic flux density, thus increasing the motor's magnetic load and consequently improving its output torque. Therefore, using Halbach PSMs is one feasible solution for effectively improving motor torque density. However, the unique magnetization direction of traditional Halbach magnets makes installation and fixation difficult. If rotor sleeves are used for reinforcement, they encroach on the air gap thickness, severely affecting the motor's electromagnetic performance. This negates the performance advantages of the Halbach PSM array, potentially even resulting in a negative performance improvement. Furthermore, the unique magnetization direction also leads to severe demagnetization at the contact points between the circumferential and radial blocks. Under overload or fault conditions, excessive armature reaction can cause large-scale demagnetization, seriously jeopardizing the safety and reliability of the motor system. In the aerospace field, this can lead to serious flight accidents, endangering lives and property. Therefore, properly managing the magnetic circuit distribution to keep the magnetic flux density at the junction of the circumferential and radial blocks of the magnet within a safe range is one of the important technical requirements for the application of Heilbeck magnets in high-safety fields.

[0004] In addition to the aforementioned requirements for high torque density and high reliability, electric drive systems must also possess high overload performance to cope with the complex operating conditions of aircraft. While the traditional Hellbeck permanent magnet rotor structure optimizes magnetic circuit guidance and significantly reduces rotor core saturation, it still fails to demonstrate significant advantages in overload performance. Therefore, how to innovatively propose a novel rotor structure that balances high torque density and high overload performance, tailored to traditional motor topologies and incorporating Hellbeck permanent magnet arrays, is one of the important directions for advancing motor technology in future aerospace electric drive systems.

[0005] The patent application CN202110253188.0 discloses an external rotor motor with a polygonal dovetail-shaped spliced ​​magnet structure. The rotor magnet is designed by splicing multiple permanent magnets with isosceles triangles or quadrilaterals in cross-section around a circle through the design of a first permanent magnet, a second permanent magnet, and a third permanent magnet, forming a closed-loop rotor magnet. The Helbeck magnetization method is used so that the electromagnetic force on the stator coil in each stator slot forms a closed loop along the circumferential tangential direction, thereby giving the external rotor a stable torque and achieving stable rotation. However, the rotor structure is too complex and may result in insufficient mechanical strength. Furthermore, the patent only sets "reinforcing ribs" on the motor shell for fixation. If the magnet is segmented axially, the stability of the installation will be seriously compromised.

[0006] Patent application CN202011388249.6 discloses a rotor structure and motor for a high torque density axial magnetic field permanent magnet motor. It combines surface-mount and built-in permanent magnet rotor structures, employing a segmented modular rotor core, and applies a Heilbeck permanent magnet array structure to an axial flux motor. This segmented rotor core structure offers advantages in ease of processing and installation. Furthermore, by using a non-magnetic rotor support disk, it reduces permanent magnet leakage, increases the main magnetic flux, and further enhances the motor's torque density. However, this solution only uses adhesive to bond the permanent magnets, without considering the potential for thermal instability of the adhesive. Additionally, when the motor speed is too high, the mechanical strength of the axial flux motor after installation will be impacted, and its application scenarios will be significantly limited.

[0007] Overall, while utilizing the magnetic focusing effect of the Heilbeck permanent magnet array, there are still problems such as the difficulty of assembling the Heilbeck permanent magnet array, serious demagnetization, and low overload performance. Summary of the Invention

[0008] In response to the shortcomings and improvement needs of existing technologies, this invention provides a motor rotor structure, assembly method, and motor with a magnetic focusing effect. The purpose is to effectively solve the problems of high assembly difficulty, severe demagnetization, and low overload performance of the Heilbeck permanent magnet array while utilizing the magnetic focusing effect of the Heilbeck permanent magnet array.

[0009] To achieve the above objectives, according to one aspect of the present invention, a motor rotor structure with a magnetic focusing effect is provided, including a rotor core and a Heilbeck magnet array embedded in the rotor core; the Heilbeck magnet array includes circumferentially magnetized magnets and radially magnetized magnets alternately distributed along the circumferential direction; the radial thickness of the radially magnetized magnets is greater than the radial thickness of the circumferentially magnetized magnets, such that rotor core bosses are formed at each circumferentially magnetized magnet location;

[0010] The radially magnetized magnet is divided into N magnet blocks along the circumference. The magnet located in the center is called the center block, and the magnet blocks on both sides are called the side blocks. The radial thickness of the side blocks gradually increases from the outer side to the inner side, and the radial thickness of the center block is not less than the maximum radial thickness of the side blocks.

[0011] Where N≥3; the outer edge of the edge block is the side adjacent to the circumferentially magnetized magnet, and the inner edge is the side closest to the center block.

[0012] Furthermore, the two sides of the radially magnetized magnet are recessed towards the central block, forming a "V" shape, and the apex of the "V" shape is the intersection of the outer side of the side block, the circumferentially magnetized magnet, and the rotor core boss.

[0013] Furthermore, in the same radially magnetized magnet, there is an angle between the magnetization direction of the side block and the magnetization direction of the center block.

[0014] Furthermore, the angle between the magnetization direction of the side blocks and the magnetization direction of the center block in the same radially magnetized magnet is set as follows:

[0015] Using the angle between the magnetization direction of the side block and the magnetization direction of the center block in the same radial magnetized magnet as the optimization variable, and taking the maximum motor torque and the minimum demagnetization at the intersection of the outer side of the side block, the circumferential magnetized magnet and the rotor core boss as the objectives, a multi-objective optimization model is established.

[0016] Solve the multi-objective optimization model and set the solution result as the angle between the magnetization direction of the side block and the magnetization direction of the center block in the same radially magnetized magnet.

[0017] In some alternative embodiments, the radially magnetized magnet is in the shape of a "crown" with its thickness gradually decreasing radially from the center to both sides.

[0018] In some alternative embodiments, the top of the central block in the radially magnetized magnet is flattened.

[0019] According to another aspect of the present invention, an assembly method for the above-described motor rotor structure with a magnetic focusing effect is provided, comprising:

[0020] After each radial magnet is magnetized, it is embedded into the corresponding magnet slot in the rotor core.

[0021] After magnetizing each circumferential magnet, it is embedded into the corresponding magnet slot in the rotor core.

[0022] According to another aspect of the present invention, a permanent magnet synchronous motor is provided, comprising the motor rotor structure with magnetic focusing effect described above provided by the present invention.

[0023] In summary, the above-described technical solutions conceived in this invention can achieve the following beneficial effects:

[0024] (1) In the motor rotor structure with magnetic focusing effect provided by the present invention, the radial thickness of the radially magnetized magnet in the Heilbeck magnet array is greater than the radial thickness of the circumferentially magnetized magnet, so that the rotor core forms a rotor core boss at the circumferentially magnetized magnet. This rotor core boss can play a role in installing, fixing and positioning the radially magnetized magnet, effectively solving the problem of difficult magnet assembly. At the same time, the presence of the rotor core boss makes the magnetic reluctance of the rotor core d-axis and q-axis no longer consistent, thereby introducing a magnetic reluctance torque component into the motor. When the motor is running under high load conditions, the magnetic weakening method can be adopted to further improve the motor torque, improve the motor torque density and overload performance. In the present invention, the radially magnetized magnet is divided into multiple segments along the circumference, and the radial thickness of the side block gradually increases from the outer side to the inner side, which increases the effective core area between adjacent radially magnetized magnets, alleviates the saturation phenomenon of the rotor core, further improves the torque density of the motor, and alleviates the demagnetization. Overall, this invention can effectively solve the problems of difficult assembly, severe demagnetization, and low overload performance of Halebec permanent magnet arrays while utilizing the magnetic focusing effect of Halebec permanent magnet arrays.

[0025] (2) In a preferred embodiment of the present invention, the two sides of the radially magnetized magnet are recessed toward the central block, forming a “V” shape. The end of the “V” shape is the intersection of the outer side of the side block, the circumferentially magnetized magnet, and the rotor core boss. Based on this structural design, the side block can be engaged with the rotor core boss. When the motor rotor rotates, the rotor core will exert a tight pressure on the magnet through this side to ensure the assembly and fixation of the radially magnetized magnet. At the same time, it plays a fixing and tight pressing role on the circumferentially magnetized magnet. Thus, when the motor rotor rotates, the rotor core forms a continuous self-fixing effect on the radially magnetized magnet and the radially magnetized magnet on the circumferentially magnetized magnet, reducing the dependence on adhesive force.

[0026] (3) In a preferred embodiment of the present invention, the magnetization directions of the side blocks and the center blocks in the radially magnetized magnets are different, but exist at a certain angle. This can further alleviate the saturation of the rotor core, increase the torque density of the motor, and prevent the permanent magnets from demagnetizing. In a further preferred embodiment, the angle between the magnetization directions of the side blocks and the center blocks is optimized by comprehensively considering the motor torque and demagnetization, thereby achieving the optimal overall performance of the motor.

[0027] (4) In some optional embodiments of the present invention, the radially magnetized magnet is in the shape of a crown with the thickness gradually decreasing from the center to both sides. This can maximize the effective core area between adjacent radially magnetized magnets, thereby maximizing the relief of rotor core saturation, increasing motor torque density, and preventing permanent magnet demagnetization. In other optional embodiments, the top of the center block of the radially magnetized magnet is flattened. This can save magnet usage and reduce motor cost while using the structural design of the side blocks to alleviate rotor core demagnetization. Attached Figure Description

[0028] Figure 1 A schematic diagram of a rotor structure with a magnetic focusing effect provided in Embodiment 1 of the present invention;

[0029] Figure 2 This is a schematic diagram of the d-axis and q-axis currents in the rotor structure provided in Embodiment 1 of the present invention, and a vector diagram of the motor space.

[0030] Figure 3 A schematic diagram of the main magnetic circuit magnetic lines and the effective core area in the rotor structure provided in Embodiment 1 of the present invention;

[0031] Figure 4 This is a schematic diagram of a rotor structure with a magnetic focusing effect provided in Embodiment 2 of the present invention;

[0032] Figure 5 This is a schematic diagram of a rotor structure with a magnetic focusing effect provided in Embodiment 3 of the present invention;

[0033] Figure 6 This is a schematic diagram of the d-axis and q-axis currents in the rotor structure provided in Embodiment 1 of the present invention, and a vector diagram of the motor space.

[0034] Figure 7 This is a schematic diagram of a rotor structure with a magnetic focusing effect provided in Embodiment 4 of the present invention;

[0035] In all the accompanying drawings, the same reference numerals are used to denote the same elements or structures, wherein:

[0036] 1-Rotor core, 2-Rotor core boss, 3-Circumferential magnet, 4-Radial magnet, 5-Center block, 6-Side block. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0038] In this invention, the terms "first," "second," etc. (if present) in the invention and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0039] To achieve both good electromagnetic performance of the motor and secure assembly of the magnets and rotor core without the need for a rotor sheath, while also improving the motor's overload performance, this invention provides a motor rotor structure, assembly method, and motor with a magnetic focusing effect. The overall concept involves improving the structure of the radially magnetized magnets in the Heilbeck magnet array. This improvement creates rotor core bosses on the rotor core for mounting, fixing, and positioning the radially magnetized magnets. These bosses introduce reluctance torque components, increasing the motor's torque density and overload performance. Furthermore, increasing the rotor core area between adjacent radially magnetized magnets reduces the rotor core's saturation, further enhancing the motor's torque density and preventing permanent magnet demagnetization.

[0040] The rotor structure provided by this invention can be applied to both radial flux outer rotor motor topologies and radial flux inner rotor motor topologies. It is easy to understand that in the radial flux outer rotor motor topology, the Halebeck magnet array is embedded in the inner circumference of the rotor core; in the radial flux inner rotor motor topology, the Halebeck magnet array is embedded in the outer circumference of the rotor core.

[0041] The following is an example.

[0042] Example 1:

[0043] A motor rotor structure with a magnetic focusing effect is described in this embodiment, which is applicable to a radial flux external rotor permanent magnet motor topology, such as... Figure 1 , Figure 2 and Figure 3 As shown, the rotor core 1 includes a rotor core 1 and a Hellbeck magnet array embedded in the inner circumference of the rotor core 1. The Hellbeck magnet array includes circumferentially magnetized magnets 3 and radially magnetized magnets 4 that are alternately distributed along the circumference. The radial thickness of the radially magnetized magnets 4 is greater than the radial thickness of the circumferentially magnetized magnets 3, so that the rotor core 2 forms rotor core bosses 2 at each circumferentially magnetized magnet 3.

[0044] The radially magnetized magnet 4 is divided into 3 magnet blocks along the circumference. The magnet block located in the center is called the center block 5, and the magnet blocks located on both sides are called the side blocks 6. The radial thickness of the side blocks 6 gradually increases from the outer side to the inner side, and the radial thickness of the center block 5 is not less than the maximum radial thickness of the side blocks 6.

[0045] The outer edge of the edge block is the side adjacent to the circumferentially magnetized magnet, and the inner edge is the side closest to the center block.

[0046] In this embodiment, the radial thickness of the radially magnetized magnet is greater than the radial thickness of the circumferentially magnetized magnet, resulting in a rotor core boss on the rotor core. On one hand, this rotor core serves to install, fix, and position the radially magnetized magnet, effectively solving the problem of difficult installation of the Heilbeck magnet array. On the other hand, due to the presence of the rotor core boss 2, the magnetic reluctance along the d-axis and q-axis of the rotor core 1 is no longer consistent, such as... Figure 2 As shown, since the magnetic reluctances of the d and q axes are different, a reluctance torque component can be introduced into the motor. Therefore, when the motor is operating under high load conditions, the torque can be further obtained by weakening the magnetic field, thereby improving the torque density and overload performance of the motor.

[0047] Furthermore, this embodiment features a circumferentially segmented design for the radially magnetized magnets, with the radial thickness of the side blocks gradually increasing from the outer edge to the inner edge. Specifically, the uppermost side of the side block closest to the rotor core forms a slope with the center block, increasing the effective core area between adjacent radially magnetized magnets, alleviating rotor core saturation, and improving the motor's torque density. Figure 3 As shown.

[0048] In practical applications, the number of segments in a radially magnetized magnet can be flexibly set to any number greater than or equal to 3, depending on actual needs. It's easy to understand that in a radially magnetized magnet, the edge blocks refer to the magnet blocks that are in contact with the circumferentially magnetized magnet on both sides, and the center block is the magnet block located in the middle of the radially magnetized magnet. Furthermore, when the number of circumferential segments in a radially magnetized magnet is odd, there is only one center block in a single radially magnetized magnet; when the number of circumferential segments in a radially magnetized magnet is even, there are two center blocks in a single radially magnetized magnet.

[0049] In practical applications, the magnetization directions of multiple magnet blocks in the same radial magnet can be the same. In this case, the magnetization directions of the side blocks and the center block are consistent, with an angle of 0°. Alternatively, the magnetization directions of multiple magnet blocks in the same radial magnet can be different. In this case, there is an angle greater than 0° between the magnetization directions of the side blocks and the center block. To further reduce the risk of motor demagnetization, as a preferred embodiment, in this example, the magnetization directions of the side blocks and the center block in the same radial magnet have an angle. This can further alleviate the saturation of the rotor core, increase the torque density of the motor, and prevent permanent magnet demagnetization. This embodiment further optimizes the magnetization angle difference design. Specifically, the angle between the magnetization directions of the side blocks and the center block in the same radial magnet is set as follows:

[0050] Using the angle between the magnetization direction of the side block and the magnetization direction of the center block in the same radial magnetized magnet as the optimization variable, and taking the maximum motor torque and the minimum demagnetization at the intersection of the outer side of the side block, the circumferential magnetized magnet and the rotor core boss as the objectives, a multi-objective optimization model is established.

[0051] Solve the multi-objective optimization model and set the solution result as the angle between the magnetization direction of the side block and the magnetization direction of the center block in the same radially magnetized magnet.

[0052] In the Heilbeck magnet array designed in this embodiment, the intersection of the outer edge of the radially magnetized magnet block, the circumferentially magnetized magnet, and the rotor core boss is the point with the greatest demagnetization in the entire motor. This embodiment uses the degree of demagnetization at this point as one of the optimization targets, which can effectively prevent the demagnetization of permanent magnets and effectively improve the overall performance of the motor.

[0053] In practical applications, the shape of the radially magnetized magnets, except for the edge blocks, can be determined by considering both cost and performance, such as... Figure 1 As shown, in this embodiment, the radially magnetized magnets are crown-shaped with their thickness gradually decreasing radially from the center to both sides. This maximizes the effective core area between adjacent radially magnetized magnets, thereby alleviating rotor core saturation to the greatest extent, increasing motor torque density, and preventing permanent magnet demagnetization. It should be noted that this is only an optional implementation and should not be construed as the sole limitation of the invention. In other embodiments of the invention, the top of the center block in the radially magnetized magnets can also be flattened, thereby saving magnet usage and reducing motor cost while utilizing the side block structure design to alleviate rotor core demagnetization.

[0054] In this embodiment, the material of the magnet can be a rare earth permanent magnet, such as neodymium iron boron, samarium cobalt, etc.; the material of the rotor core can be a silicon steel sheet or a magnetically conductive soft magnetic material such as magnetically conductive steel.

[0055] In summary, the trapezoidal circumferential magnets, the segmented circumferential radial magnets, and the rotor core bosses proposed in this embodiment work together to ensure that the Heilbeck magnets are firmly secured to the rotor core during rotor rotation. This eliminates the need for additional rotor sheaths that could compromise the motor's electromagnetic performance, thus significantly improving the motor's torque density and efficiency. Furthermore, based on the self-fixing rotor structure, different magnetization directions are used for the segmented circumferential radial magnets to better optimize the magnetic circuit guidance, reduce the risk of rotor core saturation and permanent magnet demagnetization, and ensure high torque density and high reliability. The rotor core boss design introduces a reluctance torque component into the motor, enabling it to further increase torque density under high load conditions through magnetic weakening, thereby enhancing the motor's overload capacity. The technology proposed in this patent can be applied to both radial flux external rotor motor topologies and radial flux internal rotor motor topologies, exhibiting strong portability and versatility. It focuses on further improving the torque density and overload capacity of the motor, while also addressing issues such as high reliability and ease of assembly. This will effectively promote the application and promotion of this type of motor in industry, especially in fields such as electric vehicles and aerospace where high motor efficiency and power density are required.

[0056] Example 2:

[0057] A motor rotor structure with a magnetic focusing effect. This embodiment is similar to Embodiment 1 above, except that this embodiment is applicable to a radial flux internal rotor permanent magnet motor topology, such as... Figure 4 As shown, it includes a rotor core 1 and a Heilbeck magnet array embedded in the outer circumference of the rotor core 1.

[0058] Similar to Embodiment 1 above, in this embodiment, the Heilbeck magnet array includes circumferentially magnetized magnets 3 and radially magnetized magnets 4, which are alternately distributed along the circumference. The radial thickness of the radially magnetized magnets 4 is greater than the radial thickness of the circumferentially magnetized magnets 3, so that the rotor core 2 forms rotor core bosses 2 at each of the circumferentially magnetized magnets 3. The radially magnetized magnets 4 are divided into 3 magnet blocks along the circumference, with the central magnet block being the central block 5 and the magnet blocks on both sides being the side blocks 6. The radial thickness of the side blocks 6 gradually increases from the outer side to the inner side, and the radial thickness of the central block 5 is not less than the maximum radial thickness of the side blocks 6.

[0059] In this embodiment, the specific implementation of the Heilbeck magnet array can be referred to the description in Embodiment 1 above, and will not be repeated here.

[0060] Example 3:

[0061] A motor rotor structure with a magnetic focusing effect is disclosed in this embodiment, which is applicable to a radial flux external rotor permanent magnet motor topology. This embodiment is similar to Embodiment 1 above, except that, considering that in Embodiment 1, the fixing of the rotor magnets still heavily relies on the adhesive force of high-temperature glue, etc., this invention further optimizes the design of the radially and circumferentially magnetized magnets in the Heilbeck magnet array, proposing a Heilbeck structure with continuous sub-fixing capability.

[0062] Similar to Embodiment 1 above, as Figure 5 and Figure 6 As shown, this embodiment includes a rotor core 1 and a Heilbeck magnet array embedded in the inner circumference of the rotor core 1; the Heilbeck magnet array includes circumferentially magnetized magnets 3 and radially magnetized magnets 4, which are alternately distributed along the circumference; the radial thickness of the radially magnetized magnets 4 is greater than the radial thickness of the circumferentially magnetized magnets 3, so that the rotor core 2 forms rotor core bosses 2 at each of the circumferentially magnetized magnets 3; the radially magnetized magnets 4 are divided into 3 magnet blocks along the circumference, the one located in the center magnet block is the center block 5, and the magnet blocks located on both sides are the side blocks 6; the radial thickness of the side blocks 6 gradually increases from the outer side to the inner side, and the radial thickness of the center block 5 is not less than the maximum radial thickness of the side blocks 6.

[0063] Unlike Embodiment 1 described above, as Figure 5 As shown, in this embodiment, the two sides of the radially magnetized magnet are recessed towards the central block, forming a "V" shape. The apex of the "V" shape is the intersection of the outer side of the side block, the circumferentially magnetized magnet, and the rotor core boss. Correspondingly, the overall shape of the circumferentially magnetized magnet is trapezoidal, with the long side of the trapezoid near the rotor core and the short side of the trapezoid on the air gap side. Simultaneously, the rotor core boss also has a trapezoidal structure, with the long side of the trapezoid contacting the circumferentially magnetized magnet. Based on this structural design, in the radially magnetized magnet, the portion of the outer side of the side block near the core engages with the rotor core boss. When the motor rotor rotates, the rotor core exerts a tight pressure on the magnet through this side to ensure the assembly and fixation of the radially magnetized magnet. The outer side of the side block, which contacts the circumferentially magnetized magnet, provides a fixing and tightening effect on the circumferentially magnetized magnet when the motor rotates. Thus, when the motor rotor rotates, a continuous self-fixing effect is formed between the rotor core and the radially magnetized magnets, and between the radially magnetized magnets and the circumferentially magnetized magnets.

[0064] In addition, as an optional implementation method, such as Figure 5 As shown in this embodiment, the top of the center block in the radially magnetized magnet can also be flattened, thereby saving the amount of magnet used and reducing the cost of the motor while mitigating rotor core demagnetization by utilizing the structural design of the side blocks.

[0065] like Figure 6As shown in this embodiment, since the magnetic reluctances of the d and q axes are different, a magnetic reluctance torque component can be introduced into the motor. Therefore, when the motor is running under high load conditions, the magnetic field can be weakened to further obtain torque, thereby improving the torque density and overload performance of the motor.

[0066] In this embodiment, the specific implementation of the remaining structures can be referred to the description of Embodiment 1 above, and will not be repeated here.

[0067] Example 4:

[0068] A motor rotor structure with a magnetic focusing effect. This embodiment is similar to Embodiment 3 above, except that this embodiment is applicable to a radial flux internal rotor permanent magnet motor topology, such as... Figure 7 As shown, the rotor core 1 includes a rotor core 1 and a Hellbeck magnet array embedded in the inner circumference of the rotor core 1. The Hellbeck magnet array includes circumferentially magnetized magnets 3 and radially magnetized magnets 4 that are alternately distributed along the circumference. The radial thickness of the radially magnetized magnets 4 is greater than the radial thickness of the circumferentially magnetized magnets 3, so that the rotor core 2 forms rotor core bosses 2 at each circumferentially magnetized magnet 3.

[0069] The radially magnetized magnet 4 is divided into 3 magnet blocks along the circumference. The magnet block located in the center is called the center block 5, and the magnet blocks located on both sides are called the side blocks 6. The radial thickness of the side blocks 6 gradually increases from the outer side to the inner side, and the radial thickness of the center block 5 is not less than the maximum radial thickness of the side blocks 6.

[0070] In this embodiment, the specific implementation of the Heilbeck magnet array can be referred to the description of Embodiment 3 above, and will not be repeated here.

[0071] Example 5:

[0072] An assembly method for a motor rotor structure, wherein the motor rotor structure is the motor rotor structure with magnetic focusing effect provided in any one of embodiments 1 to 4 above. This embodiment includes:

[0073] After each radial magnet is magnetized, it is embedded into the corresponding magnet slot in the rotor core.

[0074] After magnetizing each circumferential magnet, it is embedded into the corresponding magnet slot in the rotor core.

[0075] In motor rotor structures with Helbeck magnet arrays, it is necessary to first magnetize one type of magnet and assemble it into the rotor core, then magnetize another type of magnet and assemble it into the rotor core, thus completing the assembly of the entire rotor structure. Because adjacent magnets of the same type have opposite magnetization directions, they attract each other after assembly into the rotor core, making installation difficult. In this embodiment, the presence of rotor core bosses in the rotor core allows for the fixing and positioning of the radially magnetized magnets after assembly, effectively reducing the assembly difficulty.

[0076] Example 6:

[0077] A permanent magnet synchronous motor includes a motor rotor structure with a magnetic focusing effect provided in any one of the above embodiments 1 to 4.

[0078] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A motor rotor structure with a magnetic focusing effect, comprising a rotor core and a Halebeck magnet array embedded in the rotor core; the Halebeck magnet array comprising circumferentially magnetized magnets and radially magnetized magnets alternately distributed along the circumference; characterized in that, The radial thickness of the radially magnetized magnet is greater than the radial thickness of the circumferentially magnetized magnet, so that the rotor core forms rotor core bosses at each circumferentially magnetized magnet. The radially magnetized magnet is divided into circumferential sections. N There are 10 magnetic steel blocks, with the central magnetic steel block being the center block and the magnetic steel blocks on both sides being the side blocks; the radial thickness of the side blocks gradually increases from the outer side to the inner side, and the radial thickness of the center block is not less than the maximum radial thickness of the side blocks. in, N ≥3; When the number of circumferential segments of the radially magnetized magnet is odd, there is only one center block in a radially magnetized magnet; when the number of circumferential segments of the radially magnetized magnet is even, there are two center blocks in a radially magnetized magnet; the outer side of the side block is the side adjacent to the circumferential magnet, and the inner side is the side closer to the center block; the two sides of the radially magnetized magnet are concave towards the center block, forming a "V" shape, and the vertex of the "V" shape is the intersection of the outer side of the side block, the circumferential magnet, and the rotor core boss.

2. The motor rotor structure with magnetic focusing effect as described in claim 1, characterized in that, In the same radially magnetized magnet, there is an angle between the magnetization direction of the side block and the magnetization direction of the center block.

3. The motor rotor structure with magnetic focusing effect as described in claim 2, characterized in that, The angle between the magnetization direction of the side blocks and the magnetization direction of the center block in the same radially magnetized magnet is set as follows: Using the angle between the magnetization direction of the side block and the magnetization direction of the center block in the same radial magnetized magnet as the optimization variable, and taking the maximum motor torque and the minimum demagnetization at the intersection of the outer side of the side block, the circumferential magnetized magnet and the rotor core boss as the objectives, a multi-objective optimization model is established. Solve the multi-objective optimization model and set the solution result as the angle between the magnetization direction of the side block and the magnetization direction of the center block in the same radially magnetized magnet.

4. The motor rotor structure with magnetic focusing effect as described in claim 1, characterized in that, The radially magnetized magnet is crown-shaped with its thickness gradually decreasing from the center to both sides.

5. The motor rotor structure with magnetic focusing effect as described in claim 1, characterized in that, In the radially magnetized magnet, the top of the central block is flattened.

6. The assembly method of the motor rotor structure with magnetic focusing effect as described in any one of claims 1 to 5, characterized in that, include: After each radial magnet is magnetized, it is embedded into the corresponding magnet slot in the rotor core. After magnetizing each circumferential magnet, it is embedded into the corresponding magnet slot in the rotor core.

7. A permanent magnet synchronous motor, characterized in that, The motor rotor structure with magnetic focusing effect as described in any one of claims 1 to 5 is included.

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