Rotor structure and motor

Abstract

This invention provides a rotor structure and a motor. The rotor structure includes a rotor core (2), on which filling slots (4) and permanent magnet slots (5) are provided. Permanent magnets (6) are installed in the permanent magnet slots (5). The filling slots (4) are distributed on the outer periphery of the rotor core (2). The filling slots (4) include q-axis filling slots (42) and d-axis filling slots (41). The q-axis filling slots (42) include connecting filling slots (43) and independent filling slots (44). The connecting filling slots (43) are arranged in the same layer as the permanent magnet slots (5) and are located at both ends of the permanent magnet slots (5). The independent filling slots (44) are located between adjacent connecting filling slots (43), and the spacing between the independent filling slots (44) and the adjacent connecting filling slots (43) on both sides is unequal. According to the rotor structure of this invention, the efficiency and performance of the motor can be improved.

Description

Technical Field

[0001] This invention relates to the field of motor technology, and more specifically, to a rotor structure and a motor. Background Technology

[0002] Permanent magnet assisted synchronous reluctance motors have advantages such as high efficiency, high power factor, high torque density, and wide response frequency, and are widely used in the field of industrial motors. However, permanent magnet assisted synchronous reluctance motors require frequency converter control and cannot achieve self-starting, resulting in self-starting problems. In addition, frequency converters are expensive and have losses, leading to a decrease in system efficiency.

[0003] The self-starting permanent magnet assisted synchronous reluctance motor combines the advantages of an asynchronous motor with the characteristics of a permanent magnet assisted synchronous reluctance motor. It achieves self-starting through the asynchronous torque generated by the rotor bars of a squirrel-cage structure, and achieves constant speed operation through permanent magnet torque and reluctance torque. Compared to an asynchronous motor, it can operate at a constant speed with low rotor losses and high efficiency; compared to an asynchronous-starting permanent magnet synchronous motor, it requires fewer permanent magnets, resulting in lower motor cost. Compared to a permanent magnet assisted synchronous reluctance motor, it does not require a frequency converter for starting, further reducing costs.

[0004] Current self-starting permanent magnet assisted synchronous reluctance motors have improved efficiency by combining a permanent magnet assisted synchronous reluctance motor with an asynchronous motor. However, the improvement in motor efficiency is still limited, which restricts the performance of the motor. Summary of the Invention

[0005] The main objective of this invention is to provide a rotor structure and motor that can improve motor efficiency and performance.

[0006] To achieve the above objectives, according to one aspect of the present invention, a rotor structure is provided, including a rotor core, on which filling slots and permanent magnet slots are provided. Permanent magnets are installed in the permanent magnet slots. The filling slots are distributed on the outer periphery of the rotor core. The filling slots include q-axis filling slots and d-axis filling slots. The q-axis filling slots include connecting filling slots and independent filling slots. The connecting filling slots are arranged in the same layer as the permanent magnet slots and are located at both ends of the permanent magnet slots. The independent filling slots are located between adjacent connecting filling slots. The spacing between the independent filling slots and the connecting filling slots on both adjacent sides is unequal.

[0007] Furthermore, under the same pole, the number of permanent magnet slots is the same as the number of permanent magnets, the number of permanent magnet slots is N, the number of filling slots is M, and 3*N < M < 6*N.

[0008] Furthermore, under the same pole, the number of q-axis filling slots is M1, 3*N≤M1≤5*N, and the number of d-axis filling slots is M2, N≤M2≤3*N.

[0009] Furthermore, along the circumferential direction of the rotor core, the thickness between two adjacent connecting filling slots is k1, the total thickness of the independent filling slots located on one side of the d-axis is k2, 0.15*k1≤k2≤0.5*k1, and the thickness of the connecting filling slots is k3, k2≤k3.

[0010] Furthermore, in the section perpendicular to the central axis of the rotor core, the distance between the extension line of the q-axis filling groove near the d-axis and the center of the rotor core is L, 0.65*R≤L≤0.85*R, where R is the outer radius of the rotor core.

[0011] Furthermore, 0.7*R≤L≤0.8*R.

[0012] Furthermore, the distance between the extension line of each q-axis filling groove near the d-axis and the center of the rotor core is equal.

[0013] Furthermore, the distance between the extension line of the side of the connecting filling groove near the d-axis and the center of the rotor core is L1, and the distance between the extension line of the side of the independent filling groove near the d-axis and the center of the rotor core is L2, where L1≤L2.

[0014] Furthermore, the q-axis filling groove has a tangent edge on the side near the outer circle of the rotor. The thickness of the tangent edge along the circumferential direction is k31. The relationship between the thickness k31 of the tangent edge and the thickness k of the q-axis filling groove where the tangent edge is located satisfies 0.3*k≤k31≤0.7*k. The included angle between the tangent edge and the radial side of the q-axis filling groove where the tangent edge is located is α, 120°≤α≤160°.

[0015] Furthermore, in a section perpendicular to the central axis of the rotor core, along the d-axis direction, the distance between the innermost permanent magnet slot and the center of the rotor core is H1, the distance between the innermost permanent magnet slot and the outermost permanent magnet slot is H2, and the distance between the outermost permanent magnet slot and the d-axis filling slot is H3, where H3 < H2 < H1.

[0016] Furthermore, 1.5*H2≤H1≤2.5*H2, 1.5*H3≤H2≤2.5*H3.

[0017] Furthermore, 0.82*R≤H1+H2+H3≤0.92*R, where R is the outer radius of the rotor core.

[0018] Furthermore, in the section perpendicular to the central axis of the rotor core, along the d-axis direction, the distance between the innermost permanent magnet slot and the outermost permanent magnet slot is H2, and the distance between the innermost connecting filling slot and the outermost connecting filling slot is k6, where 0.8*k6≤H2≤1.2*k6.

[0019] Furthermore, in a cross section perpendicular to the central axis of the rotor core, along the d-axis direction, the length of the permanent magnet located at the innermost radial direction is s1 and the thickness is d1, and the length of the permanent magnet located at the outermost radial direction is s2 and the thickness is d2, where s1 > s2 and d2 ≥ d1.

[0020] Furthermore, there are multiple d-axis filling slots. In a cross-section perpendicular to the central axis of the rotor core, the maximum radial width of the multiple d-axis filling slots is d3, the distance between adjacent d-axis filling slots is d4, and the maximum spacing between the two outermost d-axis filling slots along the circumferential direction is s3. 1.5*d2<d3<3*d2, d2<d4<2*d2, s3>s2.

[0021] Furthermore, there are dividing ribs between the connecting filling groove and the permanent magnet groove in the same layer. In the cross section perpendicular to the central axis of the rotor core, the thickness of the dividing rib is k4, and the thickness of the connecting filling groove is k3, 0.15*k3≤k4≤0.3*k3.

[0022] Furthermore, the distance between the two connecting filling grooves located on both sides of the q-axis and adjacent to the q-axis is k5, and the thickness of the connecting filling groove is k3, where k3≤k5≤2*k3.

[0023] Furthermore, in a section perpendicular to the central axis of the rotor core, the ratio between the length of at least part of the connecting filling groove along the q-axis and the length of the corresponding permanent magnet in the same layer is greater than 0.5.

[0024] Furthermore, in a cross-section perpendicular to the central axis of the rotor core, the ratio of the length to the thickness of the permanent magnet is less than 0.15.

[0025] Furthermore, the ratio of the length to the thickness of the permanent magnet ranges from [0.04, 0.14].

[0026] Furthermore, along the d-axis, the length of the permanent magnet located at the innermost radial direction is s1, and the thickness is d1; the length of the permanent magnet located at the outermost radial direction is s2, and the thickness is d2; d1 / s1 < d2 / s2.

[0027] Furthermore, the permanent magnet groove and the permanent magnet have two layers. The permanent magnet is made of rare earth permanent magnet material. The permanent magnet groove, the permanent magnet and the filling groove are arranged symmetrically with respect to the d-axis.

[0028] Furthermore, the filling slots are filled with conductive but non-magnetic material, and short-circuit end rings are set at both ends of the rotor core. The short-circuit end rings cover all the filling slots and short-circuit the filling slots to form a squirrel cage structure.

[0029] Furthermore, there are multiple d-axis filling slots. Within a section perpendicular to the central axis of the rotor core, the maximum radial width of the multiple d-axis filling slots is d3. The outer circumference of the short-circuit end ring is an arc structure, and the inner circumference is a polygon structure composed of straight lines and arcs. The radial width of the short-circuit end ring on the d-axis is dd1, and the radial width of the short-circuit end ring on the q-axis is dq2, where dd1 ≥ 1.5 * d3.

[0030] Furthermore, dq2 ≥ dd1.

[0031] Furthermore, 1.5*dd1≤dq2≤2*dd1.

[0032] According to another aspect of the present invention, an electric motor is provided, comprising a stator structure and a rotor structure, wherein the rotor structure is the rotor structure described above, and the stator structure is sleeved on the outer periphery of the rotor structure.

[0033] According to the technical solution of this invention, the rotor structure includes a rotor core with filling slots and permanent magnet slots. Permanent magnets are installed in the permanent magnet slots. The filling slots are distributed on the outer periphery of the rotor core and include q-axis filling slots and d-axis filling slots. The q-axis filling slots include connecting filling slots and independent filling slots. The connecting filling slots are arranged in the same layer as the permanent magnet slots and are located at both ends of the permanent magnet slots. The independent filling slots are located between adjacent connecting filling slots, and the spacing between the independent filling slots and the adjacent connecting filling slots on both sides is unequal. This rotor structure's arrangement of connecting filling slots and permanent magnet slots in the same layer and at both ends of the permanent magnet slots, with the independent filling slots located between adjacent connecting filling slots and the unequal spacing between the independent filling slots and the adjacent connecting filling slots on both sides, allows the magnetic conductive channels on both sides of the independent filling slots to have different magnetic conductive areas, thereby allowing different magnetic flux. This difference can improve torque ripple during motor operation, reduce motor operating noise, reduce harmonic losses, and improve motor efficiency. Attached Figure Description

[0034] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0035] Figure 1 A schematic diagram of a rotor structure according to an embodiment of the present invention is shown;

[0036] Figure 2 A partial structural diagram of a rotor structure according to an embodiment of the present invention is shown;

[0037] Figure 3 A partial structural diagram of a rotor structure according to an embodiment of the present invention is shown;

[0038] Figure 4A schematic diagram of a rotor structure according to an embodiment of the present invention is shown;

[0039] Figure 5 A comparison diagram of the rotational speeds of a motor according to an embodiment of the present invention and a motor of related technologies during the starting process is shown.

[0040] Figure 6 A comparison diagram of the permanent magnet operating points during the starting process of a motor according to an embodiment of the present invention and a motor of related technologies is shown; and

[0041] Figure 7 A graph comparing the efficiency of a motor according to an embodiment of the present invention with that of a motor in related technologies is shown.

[0042] The above figures include the following reference numerals:

[0043] 1. Rotor structure; 2. Rotor core; 3. Rotor laminations; 4. Filling slots; 41. d-axis filling slot; 42. q-axis filling slot; 43. Connecting filling slot; 44. Independent filling slot; 45. Trimmed edge; 5. Permanent magnet slot; 51. First permanent magnet slot; 52. Second permanent magnet slot; 6. Permanent magnet; 61. First permanent magnet; 62. Second permanent magnet; 7. Shaft hole; 8. Short-circuit end ring; 9. Dividing rib. Detailed Implementation

[0044] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0045] See also Figures 1 to 7 As shown, according to an embodiment of the present invention, the rotor structure includes a rotor core 2, on which a filling groove 4 and a permanent magnet groove 5 are provided. A permanent magnet 6 is installed in the permanent magnet groove 5. The filling groove 4 is distributed on the outer periphery of the rotor core 2. The filling groove 4 includes a q-axis filling groove 42 and a d-axis filling groove 41. The q-axis filling groove 42 includes a connecting filling groove 43 and an independent filling groove 44. The connecting filling groove 43 is arranged in the same layer as the permanent magnet groove 5 and is located at both ends of the permanent magnet groove 5. The independent filling groove 44 is located between adjacent connecting filling grooves 43. The distance between the independent filling groove 44 and the connecting filling grooves 43 on both sides is unequal.

[0046] The connecting filling slot 43 of the rotor structure is arranged in the same layer as the permanent magnet slot 5 and is located at both ends of the permanent magnet slot 5. The independent filling slot 44 is located between the adjacent connecting filling slots 43. The spacing between the independent filling slot 44 and the adjacent connecting filling slots 43 on both sides is not equal, which allows the magnetic conductive channels on both sides of the independent filling slot 44 to have different magnetic conductive areas. This results in different magnetic flux allowed to pass through on both sides of the independent filling slot 44. This difference can reduce the cogging torque of the motor, reduce the torque pulsation during motor operation, reduce the operating noise of the motor, reduce harmonic losses, and improve motor efficiency.

[0047] The rotor structure can improve the magnetic flux density and magnetic flux utilization of the motor and reduce the cogging torque by optimizing the distribution of the filling slots 4. It is suitable for various application scenarios such as electric vehicles, industrial motors, and household appliance motors, and the performance of the motor is significantly improved.

[0048] In one embodiment, the rotor core 2 is formed by axially stacking multiple rotor laminations 3. The rotor laminations 3 are provided with multiple filling grooves 4, multiple permanent magnet grooves 5 and shaft holes 7. Permanent magnets 6 are inserted into the permanent magnet grooves. The filling grooves 4 are distributed on the outer periphery of the rotor laminations 3.

[0049] In one embodiment, under the same pole, the number of permanent magnet slots 5 is the same as the number of permanent magnets 6, the number of permanent magnet slots 5 is N, the number of filling slots 4 is M, and 3*N < M < 6*N.

[0050] In one embodiment, under the same pole, the number of q-axis filling slots 42 is M1, 3*N≤M1≤5*N, and the number of d-axis filling slots 41 is M2, N≤M2≤3*N.

[0051] This design can effectively improve the starting torque of the motor by increasing the number and distribution of the filling slots 4. The filling slots 4 will form a squirrel cage effect during the asynchronous start-up phase, generating asynchronous torque to help the motor accelerate from a stationary state to synchronous speed, thus improving the motor's starting capability.

[0052] The number M1 of q-axis filling slots 42 satisfies 3N≤M1≤5N. Under one pole, the number of q-axis filling slots 42 is 3 to 5 times the number of permanent magnet slots 5. This helps to increase the magnetic reluctance of the motor in the q-axis direction, thereby increasing the magnetic reluctance torque during operation and improving the synchronous operation performance and efficiency of the motor.

[0053] The number M2 of d-axis filling slots 41 satisfies N≤M2≤3*N. Under one pole, the number of d-axis filling slots 41 is 1 to 3 times the number of permanent magnet slots. The presence of d-axis filling slots 41 can improve the demagnetization resistance of permanent magnets and also reduce the amount of permanent magnets used to a certain extent, thus reducing costs.

[0054] By optimizing the number and layout of the filling slots 4, the high starting torque requirement during motor startup and the high efficiency and low cost requirements during operation are both taken into account. During startup, the squirrel-cage effect is crucial for increasing starting torque, while during operation, the appropriate use of reluctance torque and permanent magnets helps improve motor efficiency and reduce operating costs. By rationally setting the relative number and distribution of the filling slots 4 and permanent magnet slots 5, a dual improvement in motor starting capability and operating efficiency can be achieved.

[0055] In one embodiment, along the circumferential direction of the rotor core 2, the thickness between two adjacent connecting filling grooves 43 is k1, the total thickness of the independent filling groove 44 located on one side of the d-axis is k2, 0.15*k1≤k2≤0.5*k1, and the thickness of the connecting filling groove 43 is k3, k2≤k3.

[0056] By adjusting the thickness and spacing of the connecting filler slots 43, the magnetic circuit design of the motor can be optimized, ensuring the formation of an effective magnetic conduction channel between the connecting filler slots 43. This improves the magnetic flux density and utilization rate of the motor, reduces cogging torque, and enhances the motor's starting capability and operating efficiency, making it suitable for industrial motors requiring high efficiency and performance. Precisely limiting the thickness and spacing of the connecting filler slots and independent filler slots effectively improves the magnetic flux distribution inside the motor, enabling it to utilize magnetic flux more efficiently during operation. The reduced cogging torque results in smoother motor operation, reduces noise and vibration during operation, and improves the motor's operating efficiency and power performance.

[0057] In one embodiment, in a cross section perpendicular to the central axis of the rotor core 2, the distance between the extension line of the side of the q-axis filling groove 42 near the d-axis and the center of the rotor core 2 is L, 0.65*R≤L≤0.85*R, where R is the outer radius of the rotor core 2.

[0058] The selection of this range is based on the motor's magnetic circuit design and considerations for optimizing reluctance torque, aiming to ensure that the filler slot has sufficient depth to generate effective asynchronous torque during motor startup. Specifically, the depth of the filler slot affects its conductivity during the asynchronous startup phase. The greater the depth, the longer the current path can be formed by materials that are usually conductive but not magnetic, such as aluminum or copper, resulting in stronger asynchronous torque and facilitating rapid motor startup.

[0059] In one embodiment, 0.7*R≤L≤0.8*R. By further reducing the range of L, the filling slot can be designed to be closer to the radius center of the rotor core 2. This design can further enhance the effect of asynchronous torque, while avoiding the q-axis filling slot 42 being too close to the rotor edge, reducing filling slot losses, and thus maintaining the high efficiency of the motor.

[0060] In one embodiment, the distance between the extension line of the side of each q-axis filling groove 42 near the d-axis and the center of the rotor core 2 is equal.

[0061] In this embodiment, one pole includes two permanent magnet slots 5, namely the first permanent magnet slot 51 and the second permanent magnet slot 52, two permanent magnets 6, namely the first permanent magnet 61 and the second permanent magnet 62, four connecting filling slots 43 and two independent filling slots 44. The four connecting filling slots 43 are divided into two groups of two, and the two groups of connecting filling slots 43 are symmetrical about the d-axis. The two independent filling slots 44 are located on both sides of the d-axis and are symmetrical about the d-axis.

[0062] On one side of the d-axis, along the direction away from the q-axis, the distances between the extension lines of the two connecting filling slots 43 and one independent filling slot 44 near the d-axis and the center of the rotor core 2 are L1, L2, and L3, respectively, where L1 = L2 = L3. L1 = L2 = L3 indicates that the distances between each q-axis filling slot 42 and the center of the rotor core are equal. This design enables a smoother and more reliable motor starting process. Combined with the aforementioned constraint on the relationship between L and R, it ensures that the q-axis filling slot 42 has a certain length radially, thereby effectively improving the motor's starting capability.

[0063] With this design, the motor can reach synchronization more quickly during startup, reducing startup time. At the same time, during startup, the squirrel cage effect formed by the material in the filling slot can protect the permanent magnet, preventing excessive demagnetization of the permanent magnet under high starting torque, and ensuring stable magnetic performance of the motor during startup and operation.

[0064] In one embodiment, the q-axis filling groove 42 extends in a direction generally parallel to the q-axis; the permanent magnet groove 5 is perpendicular to the d-axis or extends at both ends in a direction generally parallel to the q-axis.

[0065] In one embodiment, the distance between the extension line of the side of the connecting filling groove 43 near the d-axis and the center of the rotor core 2 is L1, and the distance between the extension line of the independent filling groove 44 near the d-axis and the center of the rotor core 2 is L2, where L1≤L2.

[0066] On one side of the d-axis, along the direction away from the q-axis, the distances between the extension lines of the two connecting filling slots 43 and one independent filling slot 44 near the d-axis and the center of the rotor core 2 are L1, L2, and L3, respectively, where L2 ≥ L1 = L3. By limiting the distances between the independent filling slot 44 and the connecting filling slot 43 and the center of the rotor core 2, a good starting effect can be achieved.

[0067] In one embodiment, the q-axis filling groove 42 has a tangent edge 45 near the outer circle of the rotor. The thickness of the tangent edge 45 in the circumferential direction is k31. The relationship between the thickness k31 of the tangent edge 45 and the thickness k of the q-axis filling groove 42 where the tangent edge 45 is located satisfies 0.3*k≤k31≤0.7*k. The included angle between the tangent edge 45 and the radial side of the q-axis filling groove 42 where the tangent edge 45 is located is α, where 120°≤α≤160°.

[0068] Setting the condition 0.3*k≤k31≤0.7*k means that the thickness of the tangent edge is controlled between 30% and 70% of the filler groove thickness. This design considers a balance between two aspects: on the one hand, the tangent edge cannot be too narrow, otherwise it cannot effectively change the shape of the filler groove, and its effect on improving the magnetic field distribution is limited; on the other hand, the tangent edge cannot be too wide, otherwise it will excessively reduce the magnetic permeability area of ​​the filler groove, which may affect the starting capability and reluctance torque of the motor. An appropriate proportion of tangent edge thickness helps to adjust the permeability of the filler groove, optimize the magnetic field distribution, and thus reduce torque ripple.

[0069] Setting the angle range of 120°≤α≤160° ensures that the tangent edge forms an obtuse angle with the edge of the q-axis filling groove. This avoids sharp transitions in the magnetic field and reduces magnetic field distortion. The obtuse angle design helps to smooth the magnetic field distribution, reduce abrupt changes in local magnetic field strength, and thus reduce torque pulsation caused by magnetic field inhomogeneity.

[0070] In this embodiment, the thickness k of the q-axis filling groove 42 where the cut edge 45 is located varies depending on the q-axis filling groove 42. When the q-axis filling groove 42 is a connected filling groove 43, k takes the value k3, 0.3*k3≤k31≤0.7*k3. When the q-axis filling groove 42 is an independent filling groove 44, assuming that the number of independent filling grooves 44 on one side of the d-axis is one, the thickness of the independent filling groove 44 is k2, 0.3*k2≤k31≤0.7*k2.

[0071] In one embodiment, in a cross section perpendicular to the central axis of the rotor core 2, along the d-axis direction, the distance between the innermost permanent magnet slot 5 and the center of the rotor core 2 is H1, the distance between the innermost permanent magnet slot 5 and the outermost permanent magnet slot 5 is H2, and the distance between the outermost permanent magnet slot 5 and the d-axis filling slot 41 is H3, where H3 < H2 < H1.

[0072] In one embodiment, 1.5*H2≤H1≤2.5*H2, 1.5*H3≤H2≤2.5*H3.

[0073] The values ​​of H1, H2, and H3 gradually increase, indicating a shift from the rotor center to the outer periphery. This fully utilizes the rotor space, avoiding excessive compression of the permanent magnets near the center, which could lead to performance degradation. Simultaneously, arranging more filler slots and a squirrel-cage structure on the outer periphery enhances the motor's starting capability and demagnetization resistance. Reluctance torque is a crucial characteristic of synchronous reluctance motors, originating from the torque generated by the difference in reluctance between the d and q axes during rotor rotation. Increasing the dimensional differences between H1, H2, and H3 increases the reluctance difference between the d and q axes, thereby increasing the reluctance torque and resulting in stronger output capability during synchronous operation.

[0074] The configuration of H1, H2, and H3 also affects the magnetic circuit design of the motor. A reasonable magnetic circuit design can reduce losses on the magnetic flux path and improve the utilization rate of magnetic flux. Furthermore, setting 0.82*R≤H1+H2+H3≤0.92*R ensures that the permanent magnet slot 5 and the filling slot 4 are positioned appropriately on the rotor, avoiding excessively narrow or wide magnetic circuits, reducing magnetic saturation and leakage, and thus improving the overall efficiency of the motor.

[0075] In one embodiment, 0.82*R≤H1+H2+H3≤0.92*R, where R is the outer radius of the rotor core 2. More precise dimensional control can further improve the reluctance torque of the motor while maintaining good magnetic flux distribution.

[0076] In one embodiment, in a cross section perpendicular to the central axis of the rotor core 2, along the d-axis direction, the distance between the innermost permanent magnet slot 5 and the outermost permanent magnet slot 5 is H2, and the distance between the innermost connecting filling slot 43 and the outermost connecting filling slot 43 is k6, where 0.8*k6≤H2≤1.2*k6.

[0077] In this embodiment, since the connecting filling groove 43 has two layers, k6 = k1.

[0078] The area between the permanent magnet slots 5 forms the q-axis magnetic channel. A suitable thickness prevents oversaturation, which would affect the motor's q-axis magnetic field and inductance, thus impacting the reluctance torque. The spacing thickness H2 between the permanent magnet slots 5 is the q-axis magnetic channel, directly related to the motor's reluctance characteristics. By setting the relationship between H2 and k4, the thickness of the q-axis magnetic channel can be ensured to be moderate, avoiding oversaturation due to an excessively wide channel or ineffective flux flow due to an excessively narrow channel. A suitable H2 ensures good reluctance torque during motor operation, thereby improving the motor's output and efficiency.

[0079] In one embodiment, in a cross section perpendicular to the central axis of the rotor core 2, along the d-axis direction, the length of the innermost permanent magnet 6 is s1 and the thickness is d1, and the length of the outermost permanent magnet 6 is s2 and the thickness is d2, where s1 > s2 and d2 ≥ d1.

[0080] The motor torque mainly consists of two parts: permanent magnet torque and reluctance torque. In the permanent magnet slot design, the inner permanent magnet length s1 is greater than the outer permanent magnet length s2, meaning the inner permanent magnet has a larger area and can therefore provide more magnetic flux. Part of this flux is connected in series with the outer permanent magnet, and part passes through the q-axis magnetic channel, increasing the q-axis flux. Simultaneously, this unequal width design also affects the motor's torque characteristics; the outer permanent magnet slot is narrower, and its corresponding outer circular area is smaller. The narrower permanent magnet improves the utilization rate of the permanent magnet.

[0081] Setting the outer permanent magnet thickness d2 to be greater than or equal to the inner permanent magnet thickness d1 enhances the permanent magnet's resistance to demagnetization. The thickness of the permanent magnet is directly related to its resistance to demagnetization; a greater thickness results in stronger resistance. During motor operation, especially during startup and overload conditions, permanent magnets are susceptible to demagnetization due to external magnetic fields. Increasing the thickness of the outer permanent magnet effectively resists these external magnetic fields, reducing the risk of demagnetization and ensuring stable motor operation under various conditions.

[0082] In one embodiment, there are multiple d-axis filling slots 41. In a cross section perpendicular to the central axis of the rotor core 2, the maximum radial width of the multiple d-axis filling slots 41 is d3, the distance between adjacent d-axis filling slots 41 is d4, and the maximum spacing between the two outermost d-axis filling slots 41 in the circumferential direction is s3, where 1.5*d2 < d3 < 3*d2, d2 < d4 < 2*d2, and s3 > s2.

[0083] Setting the d3 thickness between 1.5d2 and 3d2 effectively improves the rotor's mechanical strength and creates a magnetic barrier near the permanent magnet, helping to prevent the magnetic field from directly passing through the permanent magnet during motor operation, thereby reducing the risk of demagnetization. Simultaneously, an appropriate d3 thickness ensures the formation of the squirrel cage structure, enhancing the motor's self-starting capability through the asynchronous torque of the squirrel cage.

[0084] The range of d4 is set between 1d2 and 2d2 to ensure that the distribution between the filling slots is neither too dense, which would lead to material waste and reduced mechanical strength, nor too sparse, which would weaken the squirrel cage effect. A reasonable setting of d4 can form an effective magnetic path while avoiding magnetic circuit saturation and optimizing the motor's starting characteristics.

[0085] The length s3 is set to be greater than the thickness s2 of the permanent magnet. This length setting can ensure that the filling slots are sufficiently distributed in the circumference of the rotor. This not only increases the area of ​​the conductive material and improves the conductivity of the squirrel cage during the start-up phase, thereby enhancing the asynchronous starting torque, but also helps to form a more uniform magnetic barrier, thus better protecting the permanent magnet and preventing demagnetization.

[0086] In one embodiment, a dividing rib 9 is provided between the connecting filling groove 43 and the permanent magnet groove 5 in the same layer. In a cross section perpendicular to the central axis of the rotor core 2, the thickness of the dividing rib 9 is k4, and the thickness of the connecting filling groove 43 is k3, where 0.15*k3≤k4≤0.3*k3.

[0087] Appropriate dividing ribs 9 can reduce magnetic leakage and simultaneously separate the filling groove 4 from the permanent magnet groove 5.

[0088] In one embodiment, the distance between two connecting filling grooves 43 located on both sides of the q-axis and adjacent to the q-axis is k5, and the thickness of the connecting filling groove 43 is k3, where k3≤k5≤2*k3.

[0089] Appropriate inter-pole squirrel cage slot settings can reduce motor torque pulsation and improve motor efficiency.

[0090] In one embodiment, within a cross-section perpendicular to the central axis of the rotor core 2, the length of the connecting filler groove along the q-axis is more than twice the thickness of the connecting filler groove, i.e., s11 / k3 > 0.5. The q-axis filler groove extending towards the shaft hole 7 can, on the one hand, increase the area of ​​the filler groove and modify the motor's starting capability, and on the other hand, the generated asynchronous magnetic field can increase the demagnetization resistance of the permanent magnet.

[0091] In one embodiment, the ratio of the area O1 of the connecting filling groove 43 at both ends of the permanent magnet groove 5 to the area O2 of the permanent magnet groove 5 satisfies: 0.4≤O1 / O2≤1, and the ratio of the area O1 of the outer connecting filling groove 43 to the area O2 of the permanent magnet groove 5 is greater than the ratio of the area O1 of the inner connecting filling groove 43 to the area O2 of the permanent magnet groove 5.

[0092] In one embodiment, in a cross section perpendicular to the central axis of the rotor core 2, the ratio between the length of at least part of the connecting filling groove 43 along the q-axis and the length of the corresponding permanent magnet 6 in the same layer is greater than 0.5.

[0093] In this embodiment, the length of the innermost connecting filling groove 43 is s11, the length of the permanent magnet in the same layer is s1, and s11 / s1 > 0.5. The length of the outermost connecting filling groove 43 is s22, the length of the permanent magnet in the same layer is s2, and s22 / s2 > 0.5.

[0094] The area ratio of the connecting filling groove 43 at both ends of the permanent magnet slot to that of the permanent magnet slot 5 is designed to be between 0.4 and 1, with the outer layer being larger than the inner layer. This ensures a good balance between the squirrel-cage asynchronous torque and the permanent magnet braking torque during motor startup. The squirrel-cage asynchronous torque is mainly responsible for motor startup, while the permanent magnet braking torque contributes to the stability and efficiency of the motor during constant speed operation.

[0095] The area of ​​the connecting filling groove 43 gradually decreases from the direction away from the q-axis. This gradient design allows the squirrel-cage asynchronous torque to be more concentrated on the rotor surface when the motor starts, thereby enhancing the torque output during the start-up phase.

[0096] The ratio of the length of the partial connecting filling groove 43 along the q-axis to the length of the permanent magnet in the same layer perpendicular to the d-axis is set to be greater than 0.5. This ensures that while the permanent magnet provides braking torque, the squirrel cage structure can effectively generate asynchronous torque, thereby improving the motor's starting capability and synchronous operation capability.

[0097] In one embodiment, at one pole, the ratio of the total area of ​​the permanent magnet 6 to the total area of ​​the corresponding permanent magnet slot 5 is c, where 0.4 ≤ c ≤ 0.7.

[0098] In one embodiment, in a cross-section perpendicular to the central axis of the rotor core 2, the ratio of the length to the thickness of the permanent magnet 6 is less than 0.15.

[0099] In one embodiment, the ratio of the length to the thickness of the permanent magnet 6 ranges from [0.04, 0.14].

[0100] For the two-layer magnetic barrier structure, the permanent magnet 6 includes a first permanent magnet 61 and a second permanent magnet 62, wherein the first permanent magnet 61 has a length of s1 and a thickness of d1, and the second permanent magnet 62 has a length of s2 and a thickness of d2.

[0101] In one embodiment, along the d-axis direction, the length of the innermost permanent magnet 6 is s1 and the thickness is d1, and the length of the outermost permanent magnet 6 is s2 and the thickness is d2, where d1 / s1 < d2 / s2.

[0102] The ratio c of the permanent magnet area to the corresponding permanent magnet slot area is in the range of 0.4 to 0.7. This ratio ensures a good match between the permanent magnet 6 and the permanent magnet slot 5. The proportion of the permanent magnet 6 occupying the slot area is moderate, which helps to optimize the magnetic circuit design of the motor, improve the magnetic flux utilization of the permanent magnet, reduce the amount of permanent magnet used, and thus improve the reluctance torque and overall efficiency of the motor.

[0103] The thickness-to-length ratios d1 / s1 and d2 / s2 of the permanent magnet are controlled between 0.04 and 0.14, with d1 / s1 being smaller than d2 / s2. A smaller thickness-to-length ratio means the permanent magnet has a larger magnetic flux area, increasing the motor's output torque. An even smaller ratio in the inner layer results in a larger magnetic flux, which can increase both permanent magnet torque and reluctance torque.

[0104] In one embodiment, the permanent magnet groove 5 and the permanent magnet 6 are two layers, the permanent magnet 6 is made of rare earth permanent magnet material, and the permanent magnet groove 5, the permanent magnet 6 and the filling groove 4 are arranged symmetrically with respect to the d-axis.

[0105] In this embodiment, the permanent magnet slot 5 and the permanent magnet 6 are two-layered. The permanent magnet 5 is made of rare earth permanent magnet material. The filling slot 4, the permanent magnet slot 5 and the permanent magnet 6 are arranged symmetrically with respect to the d-axis or q-axis. The multi-layered permanent magnet slot 5 and the corresponding connecting filling slot 43 form a magnetic barrier, which makes the magnetic field of the q-axis and d-axis of the rotor structure asymmetrical, generating magnetic reluctance torque and increasing the motor output.

[0106] By adopting a double-layer permanent magnet design, the reluctance torque of the motor and the torque generated by the permanent magnet can be further improved.

[0107] In one embodiment, the filling slots 4 are filled with conductive but non-magnetic material, and short-circuit end rings 8 are respectively provided at both ends of the rotor core 2. The short-circuit end rings 8 cover all the filling slots 4 and short-circuit the filling slots 4 to form a squirrel cage structure.

[0108] Conductive but non-magnetic materials include aluminum, aluminum alloys, copper, and copper alloys.

[0109] The squirrel cage structure can generate asynchronous torque, enabling the motor to start automatically.

[0110] In one embodiment, there are multiple d-axis filling slots 41. In a cross section perpendicular to the central axis of the rotor core 2, the maximum radial width of the multiple d-axis filling slots 41 is d3. The outer circumference of the short-circuit end ring 8 is an arc structure, and the inner circumference is a polygon structure composed of straight lines and arcs. The radial width of the short-circuit end ring 8 on the d-axis is dd1, and the radial width of the short-circuit end ring 8 on the q-axis is dq2, where dd1 ≥ 1.5 * d3.

[0111] This design ensures that the short-circuit end ring can efficiently contact each filling slot, reducing waste of short-circuit end ring material, while achieving better starting capability.

[0112] The radial widths dd1 on the d-axis and dq2 on the q-axis of the short-circuit ring 8 ensure the conductivity of the squirrel cage structure while satisfying the reluctance constraint. dd1 ≥ 1.5 * d3 means that the width of the short-circuit ring 8 in the d-axis direction is at least 1.5 times the maximum radial width d3 of the d-axis filling groove. This ensures sufficient conductive area to reduce resistance, thereby generating a larger asynchronous torque at startup.

[0113] In one embodiment, dq2 ≥ dd1.

[0114] In one embodiment, 1.5*dd1≤dq2≤2*dd1.

[0115] By further refining the width requirements of the short-circuit end ring 8 in the q-axis direction, the width of dq2 not only needs to be greater than dd1, but also needs to be controlled between 1.5 and 2 times that of dd1. This helps to optimize the current path during motor startup, reduce local current concentration, and improve the uniform distribution of current while ensuring the strength and stability of the squirrel cage structure, thereby enhancing the starting torque.

[0116] By properly setting the radial width of the end ring, it can be ensured that the squirrel cage structure can work effectively when the motor starts, generating sufficient asynchronous torque, enabling the motor to start smoothly from a stationary state and reach a synchronous state, shortening the starting time, and enhancing the motor's starting capability and anti-demagnetization capability.

[0117] Through the above design, the rotor structure provided in this application can significantly improve the reluctance torque of the motor, reduce cogging torque, and enhance the overall efficiency and operating performance of the motor. Simultaneously, by filling the filling slot with conductive but non-magnetic material and setting short-circuit end rings to form a squirrel cage structure, additional torque can be provided during motor startup and low-speed operation, enhancing the motor's starting capability and low-speed running stability. This rotor structure is not only suitable for traditional applications such as electric vehicles, industrial motors, and home appliances, but also meets the special needs of emerging fields such as drones, precision instruments, and medical equipment, demonstrating broad application prospects and practical benefits. In practical applications, this rotor structure can significantly improve the motor's energy efficiency ratio, reduce energy consumption, decrease noise and vibration, and improve the stability and reliability of the equipment.

[0118] According to an embodiment of the present invention, the motor includes a stator structure and a rotor structure 1, wherein the rotor structure 1 is the rotor structure described above, and the stator structure is sleeved on the outer periphery of the rotor structure 1.

[0119] Figure 5 In comparison of the starting speed of the present invention and the prior art, the starting capability of the motor is enhanced and the starting time is significantly shortened after adopting the structure of the present invention. Figure 6In comparison with the operating point of the permanent magnet during the starting process of the present invention and the prior art, by adopting the structure of the present invention and using the filling groove to protect the permanent magnet, the minimum operating point of the permanent magnet is significantly improved during the starting process of the motor under harsh conditions, and the anti-demagnetization ability is enhanced. Figure 7 In order to compare the efficiency of the present invention with that of the prior art, under the same cost, the rotor structure of the present invention can effectively improve the motor efficiency under various load torques.

[0120] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0121] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in sequences other than those illustrated or described herein.

[0122] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., 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 rotor structure, characterized in that, The rotor core (2) includes a rotor core (2) with a filling groove (4) and a permanent magnet groove (5). A permanent magnet (6) is installed in the permanent magnet groove (5). The filling groove (4) is distributed on the outer periphery of the rotor core (2). The filling groove (4) includes a q-axis filling groove (42) and a d-axis filling groove (41). The q-axis filling groove (42) includes a connecting filling groove (43) and an independent filling groove (44). The connecting filling groove (43) is arranged in the same layer as the permanent magnet groove (5) and is located on the rotor core (2). At both ends of the magnet slot (5), the independent filling slot (44) is located between the adjacent connecting filling slot (43), and the distance between the independent filling slot (44) and the adjacent connecting filling slots (43) on both sides is not equal; the q-axis filling slot (42) has a tangent (45) on the side near the outer circle of the rotor, the thickness of the tangent (45) along the circumferential direction is k31, the relationship between the thickness k31 of the tangent (45) and the thickness k of the q-axis filling slot (42) where the tangent (45) is located satisfies 0.3*k≤k31≤0.7*k, and the included angle between the tangent (45) and the radial side of the q-axis filling slot (42) where the tangent (45) is located is α, 120°≤α≤160°.

2. The rotor structure according to claim 1, characterized in that, Under the same pole, the number of permanent magnet slots (5) is the same as the number of permanent magnets (6), the number of permanent magnet slots (5) is N, the number of filling slots (4) is M, 3*N<M<6*N.

3. The rotor structure according to claim 2, characterized in that, Under the same pole, the number of q-axis filling grooves (42) is M1, 3*N≤M1≤5*N, and the number of d-axis filling grooves (41) is M2, N≤M2≤3*N.

4. The rotor structure according to claim 1, characterized in that, Along the circumferential direction of the rotor core (2), the thickness between two adjacent connecting filling grooves (43) is k1, the total thickness of the independent filling groove (44) located on one side of the d-axis is k2, 0.15*k1≤k2≤0.5*k1, and the thickness of the connecting filling groove (43) is k3, k2≤k3.

5. The rotor structure according to claim 1, characterized in that, In a cross section perpendicular to the central axis of the rotor core (2), the distance between the extension line of the side of the q-axis filling groove (42) near the d-axis and the center of the rotor core (2) is L, 0.65*R≤L≤0.85*R, where R is the outer radius of the rotor core (2).

6. The rotor structure according to claim 5, characterized in that, 0.7*R≤L≤0.8*R.

7. The rotor structure according to claim 5, characterized in that, The distance between the extension line of the side of each q-axis filling groove (42) near the d-axis and the center of the rotor core (2) is equal.

8. The rotor structure according to claim 5, characterized in that, The distance between the extension line of the side of the connecting filling groove (43) near the d-axis and the center of the rotor core (2) is L1, and the distance between the extension line of the side of the independent filling groove (44) near the d-axis and the center of the rotor core (2) is L2, where L1≤L2.

9. The rotor structure according to claim 1, characterized in that, In a cross section perpendicular to the central axis of the rotor core (2), along the d-axis direction, the distance between the innermost permanent magnet slot (5) and the center of the rotor core (2) is H1, the distance between the innermost permanent magnet slot (5) and the outermost permanent magnet slot (5) is H2, and the distance between the outermost permanent magnet slot (5) and the d-axis filling slot (41) is H3, where H3 < H2 < H1.

10. The rotor structure according to claim 9, characterized in that, 1.5*H2≤H1≤2.5*H2, 1.5*H3≤H2≤2.5*H3.

11. The rotor structure according to claim 10, characterized in that, 0.82*R≤H1+H2+H3≤0.92*R, where R is the outer radius of the rotor core (2).

12. The rotor structure according to claim 1, characterized in that, In a cross section perpendicular to the central axis of the rotor core (2), along the d-axis direction, the distance between the innermost permanent magnet slot (5) and the outermost permanent magnet slot (5) is H2, and the distance between the innermost connecting filling slot (43) and the outermost connecting filling slot (43) is k6, 0.8*k6≤H2≤1.2*k6.

13. The rotor structure according to claim 1, characterized in that, In a cross section perpendicular to the central axis of the rotor core (2), along the d-axis direction, the length of the permanent magnet (6) located at the innermost radial side is s1 and the thickness is d1, and the length of the permanent magnet (6) located at the outermost radial side is s2 and the thickness is d2, where s1 > s2 and d2 ≥ d1.

14. The rotor structure according to claim 13, characterized in that, There are multiple d-axis filling slots (41). In a cross section perpendicular to the central axis of the rotor core (2), the maximum radial width of the multiple d-axis filling slots (41) is d3, the distance between adjacent d-axis filling slots (41) is d4, and the maximum spacing between the two outermost d-axis filling slots (41) along the circumferential direction is s3. 1.5*d2<d3<3*d2, d2<d4<2*d2, s3>s2.

15. The rotor structure according to claim 1, characterized in that, The connecting filling groove (43) and the permanent magnet groove (5) in the same layer have a dividing rib (9). In the cross section perpendicular to the central axis of the rotor core (2), the thickness of the dividing rib (9) is k4, and the thickness of the connecting filling groove (43) is k3, 0.15*k3≤k4≤0.3*k3.

16. The rotor structure according to claim 1, characterized in that, The distance between the two connecting filling grooves (43) located on both sides of the q axis and adjacent to the q axis is k5, and the thickness of the connecting filling groove (43) is k3, k3≤k5≤2*k3.

17. The rotor structure according to claim 1, characterized in that, In a cross section perpendicular to the central axis of the rotor core (2), the ratio between the length of at least a portion of the connecting filling groove (43) along the q-axis and the length of the corresponding permanent magnet (6) in the same layer is greater than 0.

5.

18. The rotor structure according to claim 1, characterized in that, In a cross section perpendicular to the central axis of the rotor core (2), the ratio of the length to the thickness of the permanent magnet (6) is less than 0.

15.

19. The rotor structure according to claim 18, characterized in that, The ratio of the length to the thickness of the permanent magnet (6) is in the range of [0.04, 0.14].

20. The rotor structure according to claim 18, characterized in that, Along the d-axis, the length of the permanent magnet (6) located at the innermost radial side is s1 and the thickness is d1, and the length of the permanent magnet (6) located at the outermost radial side is s2 and the thickness is d2, where d1 / s1 < d2 / s2.

21. The rotor structure according to claim 1, characterized in that, The permanent magnet groove (5) and the permanent magnet (6) are two layers. The permanent magnet (6) is made of rare earth permanent magnet material. The permanent magnet groove (5), the permanent magnet (6) and the filling groove (4) are arranged symmetrically with respect to the d-axis.

22. The rotor structure according to claim 1, characterized in that, The filling groove (4) is filled with conductive but non-magnetic material. Short-circuit end rings (8) are respectively provided at both ends of the rotor core (2). The short-circuit end rings (8) cover all the filling grooves (4) and short-circuit the filling grooves (4) to form a squirrel cage structure.

23. The rotor structure according to claim 22, characterized in that, There are multiple d-axis filling slots (41). In the cross section perpendicular to the central axis of the rotor core (2), the maximum radial width of the multiple d-axis filling slots (41) is d3. The outer circumference of the short-circuit end ring (8) is an arc structure, and the inner circumference is a polygon structure composed of straight lines and arcs. The radial width of the short-circuit end ring (8) on the d-axis is dd1, and the radial width of the short-circuit end ring (8) on the q-axis is dq2. dd1≥1.5*d3.

24. The rotor structure according to claim 23, characterized in that, dq2≥dd1.

25. The rotor structure according to claim 24, characterized in that, 1.5*dd1≤dq2≤2*dd1.

26. An electric motor, comprising a stator structure and a rotor structure (1), characterized in that, The rotor structure (1) is the rotor structure according to any one of claims 1 to 25, and the stator structure is sleeved on the outer periphery of the rotor structure (1).

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