Hybrid rotor for synchronous electric machine

Abstract

A synchronous electric machine includes a stator having a plurality of conductive windings configured to carry an alternating current for generating a rotating magnetic field (RMF), and a hybrid rotor configured to rotate within the stator in accordance with a torque caused by the RMF. The hybrid rotor includes a plurality of laminations axially stacked together. The laminations include a non-permanent magnet subset of the laminations having one or more through holes configured to limit torque pulsation. The laminations include a subset of permanent magnets of the laminations having one or more pockets, where the pockets each removably hold one or more permanent magnets. The permanent magnet is operable to magnetically interact with the RMF.

Description

Technical Field

[0001] The present disclosure relates generally to electric machines, and more particularly to hybrid rotors for synchronous electric machines. Background Art

[0002] Some synchronous machines include a rotor configured to rotate within a stator. Common implementations of these types of synchronous machines include a rotor having permanent magnets that is operable to rotate in response to a magnetic field from the stator. Such implementations are widely used and are generally considered adequate. However, rotors having permanent magnets may be relatively susceptible to torque ripples, particularly those resulting from oscillations of the current used in conjunction with the magnetic field from the stator. Rotors having permanent magnets may also be relatively susceptible to excessive heat that may affect the thermal properties of the rotor. This reliance on permanent magnets may affect the overall performance of the synchronous machine. Summary of the invention

[0003] One aspect of the present disclosure relates to a synchronous electric machine having a hybrid rotor. The hybrid rotor may include a plurality of laminations having a permanent magnet subset and a non-permanent magnet subset for minimizing or reducing torque ripple. The plurality of laminations may be configured to optimize the thermal performance of the rotor.

[0004] A synchronous motor is provided. The synchronous motor includes a stator and a hybrid rotor. The stator includes a plurality of conductive windings configured to carry an alternating current for generating a rotating magnetic field (RMF). The hybrid rotor is configured to rotate within the stator according to a torque caused by the RMF, and the hybrid rotor has a plurality of laminations stacked together axially. A non-permanent magnet subset of the laminations includes one or more through holes configured to limit torque pulsation. A permanent magnet subset of the laminations includes one or more recesses, each of which removably retains one or more permanent magnets. The permanent magnets are operable to interact magnetically with the RMF.

[0005] In some embodiments, the hybrid rotor includes a first non-permanent magnet lamination of a subset of non-permanent magnets at a first distal end and a second non-permanent magnet lamination of a subset of non-permanent magnets at a second distal end axially opposite the first distal end.

[0006] In some embodiments, each lamination of the subset of permanent magnets is disposed between a first distal end and a second distal end.

[0007] In some embodiments, a first permanent magnet lamination of the permanent magnet subset abuts a first non-permanent magnet lamination, and a second permanent magnet lamination of the permanent magnet subset abuts a second non-permanent magnet.

[0008] In some embodiments, the third non-permanent magnet lamination of the non-permanent magnet subset is disposed between the first and second permanent magnet laminations.

[0009] In some embodiments, the hybrid rotor includes a first permanent magnet lamination of a subset of permanent magnets at a first distal end and a second permanent magnet lamination of a subset of permanent magnets at a second distal end axially opposite the first distal end.

[0010] In some embodiments, each lamination of the subset of non-permanent magnets is disposed between a first distal end and a second distal end.

[0011] In some embodiments, an air gap separates the mixing rotor from the stator and varies axially along the length of the mixing rotor, and wherein the air gap is defined as the space between the mixing rotor and the stator.

[0012] In some embodiments, the first portion coincides with a subset of non-permanent magnets and the second portion coincides with a subset of permanent magnets.

[0013] In some embodiments, the first portion coincides with a subset of non-permanent magnets and the second portion coincides with a subset of permanent magnets.

[0014] In some embodiments, the second portion is disposed axially between a pair of first portions.

[0015] In some embodiments, a permanent magnet is removably retained in each pocket.

[0016] In some embodiments, the permanent magnet comprises a magnetic material having a self-generated persistent magnetic field.

[0017] In some embodiments, the subset of non-permanent magnets is free of magnetic material.

[0018] In some embodiments, the subset of non-permanent magnets includes steel, a soft magnetic composite material, or a combination thereof.

[0019] According to an alternative embodiment, a synchronous electric machine includes a stator and a hybrid rotor. The stator includes a plurality of conductive windings configured to carry an alternating current for generating a rotating magnetic field (RMF). The hybrid rotor is configured to rotate relative to the stator, and the hybrid rotor includes a plurality of laminations. A permanent magnet subset of the laminations includes one or more pockets for holding permanent magnets. Each permanent magnet includes a permanent magnetic material having a self-generated persistent magnetic field. A non-permanent magnet subset of the laminations is free of permanent magnetic material.

[0020] In some embodiments, the permanent magnets are operable to magnetically interact with the RMF to generate a magnetic torque in the hybrid rotor.

[0021] In some embodiments, a subset of non-permanent magnets is operable to interact with the RMF to generate reluctance torque in the hybrid rotor.

[0022] According to an alternative embodiment, a motor vehicle is provided. The motor vehicle includes a body, a plurality of drive wheels mounted to the body, and a synchronous motor mounted to the body. The synchronous motor is operable to drive one or more of the drive wheels to propel the motor vehicle. The synchronous motor includes a stator and a hybrid rotor. The stator includes a plurality of conductive windings configured to carry an alternating current for generating a rotating magnetic field (RMF). The hybrid rotor is configured to rotate within the stator according to a torque caused by the RMF. The hybrid rotor includes a plurality of laminations stacked axially together. A non-permanent magnet subset of the laminations includes one or more through holes configured to limit torque pulsations. A permanent magnet subset of the laminations includes one or more recesses, each of which removably holds one or more permanent magnets, which are operable to interact magnetically with the RMF.

[0023] The present invention may also include the following aspects.

[0024] 1. A synchronous motor, comprising:

[0025] a stator comprising a plurality of electrically conductive windings configured to carry an alternating current for generating a rotating magnetic field (RMF);

[0026] a mixing rotor configured to rotate within the stator according to a torque caused by the RMF, the mixing rotor having a plurality of laminations stacked together axially,

[0027] wherein the non-permanent magnet subset of the laminations includes one or more through holes configured to limit torque ripple; and

[0028] Wherein the permanent magnet subset of the laminations comprises one or more pockets, each of the pockets removably retaining one or more permanent magnets operable to magnetically interact with the RMF.

[0029] 2. A synchronous motor according to Scheme 1, wherein the hybrid rotor includes a first non-permanent magnet lamination of the non-permanent magnet subset at a first distal end and a second non-permanent magnet lamination of the non-permanent magnet subset at a second distal end axially opposite to the first distal end.

[0030] 3. A synchronous motor according to claim 2, wherein each lamination of the permanent magnet subset is arranged between the first distal end and the second distal end.

[0031] 4. A synchronous motor according to Option 3, wherein the first permanent magnet lamination of the permanent magnet subgroup is adjacent to the first non-permanent magnet lamination, the second permanent magnet lamination of the permanent magnet subgroup is adjacent to the second non-permanent magnet, and the third non-permanent magnet lamination of the non-permanent magnet subgroup is arranged between the first permanent magnet lamination and the second permanent magnet lamination.

[0032] 5. A synchronous motor according to claim 1, wherein the hybrid rotor comprises a first permanent magnet lamination of the permanent magnet subset at a first distal end and a second permanent magnet lamination of the permanent magnet subset at a second distal end axially opposite to the first distal end.

[0033] 6. The synchronous motor according to claim 5, wherein each lamination of the non-permanent magnet subset is arranged between the first distal end and the second distal end.

[0034] 7. A synchronous motor according to claim 1, wherein an air gap separates the hybrid rotor from the stator and varies axially along the length of the hybrid rotor, and wherein the air gap is defined as the space between the hybrid rotor and the stator.

[0035] 8. A synchronous motor according to claim 7, wherein a first thickness of a first portion of the air gap is smaller than a second thickness of a second portion of the air gap.

[0036] 9. A synchronous motor according to claim 8, wherein the first portion coincides with the non-permanent magnet subset, and the second portion coincides with the permanent magnet subset.

[0037] 10. The synchronous motor according to claim 9, wherein the second portion is axially disposed between a pair of first portions.

[0038] 11. A synchronous motor according to claim 1, wherein the permanent magnet is removably retained in each of the pockets.

[0039] 12. A synchronous motor according to claim 1, wherein the permanent magnets include a magnetic material having a self-generated persistent magnetic field, and wherein the non-permanent magnet subset is free of the magnetic material.

[0040] 13. A synchronous motor according to Option 1, wherein the non-permanent magnet subset comprises steel, a soft magnetic composite material, or a combination thereof.

[0041] 14. A synchronous machine according to claim 13, wherein the subgroup of non-permanent magnets is centrally located along the axial length of the hybrid rotor to limit demagnetization on the permanent magnets in the hybrid rotor.

[0042] 15. A synchronous motor, comprising:

[0043] a stator comprising a plurality of electrically conductive windings configured to carry an alternating current for generating a rotating magnetic field (RMF); and

[0044] A mixing rotor configured to rotate relative to the stator, the mixing rotor comprising a plurality of laminations, wherein:

[0045] The permanent magnet subsets of the laminations include one or more pockets for retaining permanent magnets, each permanent magnet subset including a permanent magnetic material having a self-generated persistent magnetic field; and

[0046] The non-permanent magnet subset of the laminations is free of permanent magnetic material.

[0047] 16. A synchronous motor according to claim 15, wherein the permanent magnets are operable to magnetically interact with the RMF to generate magnetic torque in the hybrid rotor.

[0048] 17. A synchronous motor according to Option 15, wherein the non-permanent magnet subset includes non-permanent magnetic material, wherein the non-permanent magnetic material includes one or more through holes, and the one or more through holes are capable of operating to generate a flux barrier for the RMF.

[0049] 18. A synchronous motor according to Option 17, wherein the non-permanent magnetic material has a first magnetic resistance, the one or more through holes have a second magnetic resistance, and the first magnetic resistance is greater than the second magnetic resistance.

[0050] 19. A synchronous motor according to Option 17, wherein the non-permanent magnetic material comprises steel, a soft magnetic composite material or a combination thereof.

[0051] 20. A motor vehicle comprising:

[0052] Car body;

[0053] a plurality of drive wheels mounted to the vehicle body; and

[0054] a synchronous electric machine mounted to the vehicle body and operable to drive one or more of the drive wheels to propel the motor vehicle, the synchronous electric machine comprising:

[0055] a stator comprising a plurality of electrically conductive windings configured to carry an alternating current for generating a rotating magnetic field (RMF);

[0056] a mixing rotor configured to rotate within the stator according to a torque caused by the RMF, the mixing rotor having a plurality of laminations stacked together axially,

[0057] wherein the non-magnetic subset of the laminations does not include magnets and includes one or more through holes configured to limit torque ripple; and

[0058] Wherein the magnet subset of the stack includes one or more pockets, each of which removably retains one or more magnets operable to magnetically interact with the RMF.

[0059] These features and advantages of the present teaching together with other features and advantages may be apparent from the following detailed description of the mode for implementing the present teaching in conjunction with the accompanying drawings. It should be understood that although the following drawings and embodiments may be described separately, their individual features may be combined into additional embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] The accompanying drawings, which may be incorporated in and constitute a part of this specification, illustrate embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0061] Figure 1 is a perspective view of an exemplary synchronous electric machine having a stator and a hybrid rotor within the stator according to one or more embodiments of the present disclosure.

[0062] Figure 2 is a perspective view of a portion of a mixing rotor in an exemplary configuration according to one or more embodiments of the present disclosure.

[0063] Figure 3 According to one or more embodiments of the present disclosure Figure 2 A perspective view of the non-permanent magnet subgroup of the hybrid rotor.

[0064] Figure 4 According to one or more embodiments of the present disclosure Figure 2 A perspective view of the permanent magnet subgroup of a hybrid rotor.

[0065] Figure 5-6 is a schematic cross-sectional view of a portion of a stator and a hybrid rotor of an exemplary synchronous machine having an air gap between the stator and the hybrid rotor according to one or more embodiments of the present disclosure.

[0066] Figure 7-9 is a schematic diagram of a hybrid rotor 104 having various configurations involving a non-permanent magnet subset 140 and a permanent magnet subset 150 in accordance with one or more embodiments of the present disclosure. DETAILED DESCRIPTION

[0067] As required, detailed embodiments of the present disclosure are disclosed herein; however, it should be understood that the disclosed embodiments are merely examples of the present disclosure, which may be implemented in various forms and alternative forms. The drawings are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, the specific structural and functional details disclosed herein should not be interpreted as limiting, but merely as a representative basis for teaching those skilled in the art to use the present disclosure in various ways.

[0068] Figure 1 is a perspective view of an exemplary synchronous electric machine 100 having a stator 102 and a hybrid rotor 104 within the stator 102 according to one or more embodiments of the present disclosure. The electric machine 100 includes a stator 102 having a plurality of conductive windings configured to carry an alternating current for generating a rotating magnetic field (RMF).

[0069] The motor 100 may include a base 101 coupled to a housing 114 of the motor 100 . The housing 114 may include a controller for controlling input alternating current (AC) and monitoring parameters, etc. The housing 114 may be coupled to a set of fins 117 for dissipating heat generated by the motor 100 .

[0070] A plurality of protrusions 120 are arranged around the inner periphery of the stator 102. The size, shape, number, and overall geometry of these protrusions can vary depending on the design. The protrusions collectively define stator slots 130 between adjacent protrusions. The stator slots 130 are notches in the stator insets in the inner periphery. The spacing and number of slots are related to defining various characteristics of the motor 100, such as the number of poles, the number of phases, and the number of harmonics.

[0071] Still reference Figure 1 , stator slots 130 arranged around the interior of the stator 102 open to an air gap 110 that separates the stator 102 and the mixing rotor 104. For simplicity, although the stator slots 130 in the stator 102 and the various openings in the mixing rotor 104 directly open to the air gap 110, Figure 1 The air gap 110 is defined using two circles extending around the inner circumference of the stator 102 and the exterior of the mixing rotor 104. The mixing rotor 104 in this configuration has a cylindrical profile, but this geometry can vary widely, and other rotors can use different geometries, such as using different numbers and geometries of salient poles distributed around the mixing rotor 104, or other methods. A circular housing 121 is provided across the outer circumference of the stator 102.

[0072] Although not shown to avoid overly obscuring the concepts of the present disclosure, the stator 102 includes a plurality of conductive windings configured to carry an alternating current for generating a rotating magnetic field (RMF). The plurality of conductive windings are wound around the protrusions. In this configuration, as the windings pass along the slots and thus along the longitudinal direction of the rotor, the alternating current can generate an RMF that extends (or extends out of) the radial components of the hybrid rotor 104. Depending on the geometry of the protrusions 120 and the stator slots 130 on the stator and the physical configuration of the hybrid rotor 104, the location and total number of windings may vary without departing from the spirit and scope of the present disclosure.

[0073] The hybrid rotor 104 is configured to rotate within the stator 102 according to the torque caused by the RMF. The hybrid rotor 104 includes a plurality of laminations stacked together axially, and has an axial variable reluctance profile due to the difference in laminations in the plurality of laminations. The plurality of laminations include Figure 2 A non-permanent magnet subset 140 and a permanent magnet subset 150 are shown, with the non-permanent magnet subset including one or more through holes 108 .

[0074] Figure 1 The electric machine 100 also shows a shaft 115. Depending on the application, the shaft 115 can rotate with the hybrid rotor 104 under different loads to perform work. For example, in an electric vehicle (EV), the rotating shaft can be used to rotate one or more wheels.

[0075] Additional aspects of the present disclosure relate to an electric machine 100 that is operably arranged, incorporated into, or otherwise used in a vehicle, such as a motor vehicle. As used herein, "vehicle" is understood to mean a device that is constructed to transport people, things, objects, etc. Non-limiting examples of motor vehicles (e.g., internal combustion engine (ICE) vehicles, electric vehicles including batteries and fuel cell vehicles, etc.) include land vehicles (e.g., cars, trucks, motorcycles, electric bicycles, buses, trains, etc.), aircraft (e.g., airplanes, helicopters, unmanned aerial vehicles, etc.), water vehicles (e.g., boats, watercraft, etc.), and amphibious vehicles (e.g., hovercraft, etc.).

[0076] In an example, an electric vehicle includes a body, a plurality of drive wheels mounted to the body, and a synchronous electric machine (ie, electric machine 100 ) mounted to the body and operable to drive one or more of the drive wheels to propel the electric vehicle.

[0077] The electric machine 100 can be used as a motor to convert electrical energy into mechanical energy, as previously discussed with respect to propulsion of an electric vehicle. Alternatively, the electric machine 100 can be used as a generator to convert mechanical energy into electrical energy. Regardless of the mode of use, the electric machine 100 operates according to the principles of electromagnetic induction, where the movement of a conductor within a magnetic field produces a voltage (as in the case of a motor), and the interaction between the magnetic field and the current produces mechanical motion (as in the case of a generator).

[0078] Figure 2 1 is a perspective view of a portion of a hybrid rotor 104 in an exemplary configuration according to one or more embodiments of the present disclosure. The hybrid rotor 104 includes a plurality of laminations individually stacked axially together in a side-by-side facing relationship. To simplify representation, individual laminations having the same or similar characteristics are grouped or combined into non-permanent magnet subsets 140 of laminations and non-permanent magnet subsets 150 of laminations. For example, the non-permanent magnet subset 140 may include a plurality of individual laminations without magnetic material, such as permanent magnets. The permanent magnet subset 150 may include individual laminations having permanent magnets. The subsets may be as follows: Figure 3 Shown is divided or separated.

[0079] refer to Figure 2 Due to the ability of the non-permanent magnet subset 140 and the permanent magnet subset 150 to produce reluctance torque during operation of the electric machine 100, the hybrid rotor 104 has an axially varying reluctance profile. The reluctance profile is a graphical representation or description of how the reluctance within the electric machine 100 varies with the position of the rotor relative to the stator.

[0080] The non-permanent magnet subset 140 experiences reluctance torque because it has no permanent magnets 154 and is made of a material having high magnetic permeability (ie, non-permanent magnet material). Non-permanent magnet material is defined as a material having high magnetic permeability without permanent magnets.

[0081] Since the permanent magnet subset 150 is made of non-permanent magnet material and includes Figure 4 The permanent magnets 154 are shown, so the permanent magnet subset 150 experiences both reluctance torque and magnetic torque. Non-limiting examples of non-permanent magnet materials are steel, steel laminations, soft magnetic composites (SMC), ferromagnetic cores made of silicon steel, and the like.

[0082] By increasing the reluctance torque using the non-permanent magnet subset 140, the motor 100 is able to maintain its overall torque performance while reducing the magnetic torque, ultimately minimizing or reducing torque ripple. The magnetic torque is reduced by reducing the number of permanent magnets in the lamination having permanent magnets (ie, the permanent magnet subset 140).

[0083] like Figure 2As shown, the permanent magnet subset 150 is disposed between the two non-permanent magnet subsets 140, wherein the axial length of the permanent magnet subset 150 is greater than the combined axial length of the two non-permanent magnet subsets 140. In one embodiment, the permanent magnet subset 150 may have an axial length of 65 mm. Each non-permanent magnet subset 140 may have an axial length of 20 mm. In another embodiment, the permanent magnet subset 150 may have an axial length of 70 mm. Each non-permanent magnet subset 140 may have an axial length of 10 mm.

[0084] Figure 3 According to one or more embodiments of the present disclosure Figure 2 1 is a perspective view of a non-permanent magnet subset 140 of a hybrid rotor 104. The non-permanent magnet subset 140 includes one or more through holes 108 configured to limit torque pulsation. Figure 3 As shown, the through holes 108 may be shaped as concentric rings extending in a radial direction starting from the edge of the mixing rotor 104 toward the center of the mixing rotor. In other embodiments, the through holes 108 may have a different orientation or shape.

[0085] The one or more through holes 108 may be configured to create a flux barrier, which is an air region within the hybrid rotor. The primary purpose of the flux barrier is to create a difference between high and low reluctance (i.e., magnetic resistance) within the non-permanent magnet set 140 to enable the hybrid rotor 104 to rotate due to reluctance torque.

[0086] The non-permanent magnet subset 140 can limit torque ripple by optimizing the magnetic circuit with a low reluctance path for magnetic flux in the motor 100 or by enhancing synchronization by minimizing variations in the magnetic field. Torque fluctuation, also known as torque ripple or torque variation, refers to fluctuations or variations in the output torque of the motor 100 during its operation.

[0087] Figure 4 According to one or more embodiments of the present disclosure Figure 2 1 is a perspective view of a non-permanent magnet subset 140 of a mixing rotor 104. The permanent magnet subset 150 includes one or more pockets 152, each of which removably holds one or more permanent magnets 154. The permanent magnets 154 are operable to magnetically interact with the RMF and to enable the mixing rotor 104 to rotate due to magnetic torque.

[0088] The permanent magnet 154 includes a magnetic material having a self-generated persistent magnetic field (i.e., a permanent magnet material). Non-limiting examples of the permanent magnet 154 include neodymium iron boron (NdFeB) magnets, samarium cobalt (SmCo) magnets, aluminum nickel cobalt (AlNiCo) magnets, ferrite (ceramic) magnets, rare earth magnet alloys (e.g., DyFe, dysprosium iron; TbFe, terbium iron), and / or the like.

[0089] In addition to the magnetic torque, the permanent magnet subset 150 may experience a reluctance torque due to the placement of the permanent magnets 154 inside the permanent magnet subset 150. By placing the permanent magnets 154 inside the permanent magnet subset 150, the interior of the permanent magnet subset 150 has a varying reluctance in the radial direction because the permanent magnets 154 have a different magnetic permeability than the material of the non-permanent magnet subset 140. The varying reluctance of the permanent magnet subset 150 is similar to the reluctance of the permanent magnets 154 used for an interior permanent magnet motor (IPM).

[0090] In another embodiment, the permanent magnets 154 may be fixed to the outer surface of the permanent magnet subset 150. Similar to a surface permanent magnet motor (SPM), the reluctance torque may be small or negligible compared to the magnetic torque generated by the permanent magnets 154.

[0091] Figure 5-6 1 is a schematic cross-sectional view of a portion of a stator 102 and a hybrid rotor 104 of an exemplary synchronous motor 100 according to one or more embodiments of the present disclosure, the synchronous motor having an air gap 110 between the stator 102 and the hybrid rotor. The air gap 110 separates the stator 102 from the hybrid rotor, wherein the air gap 110 has a radial distance that varies axially along the length of the hybrid rotor. The air gap 110 is defined by the stator 102 and the hybrid rotor. In other words, the air gap 110 has a thickness defined as the distance between the inner periphery of the stator 102 and the outer portion of the hybrid rotor 104. The thickness of the air gap 110 may vary axially along the length of the hybrid rotor. For example, the thicknesses 160A and 170A may be different, such as Figure 5 shown.

[0092] like Figure 5 As shown, the air gap 110 may include a first portion 160 and a second portion 170 having different radial distances. The first portion 160 has a radial distance greater than the radial distance of the second portion 170. In other words, the first portion 160 has an air gap 110 that is smaller than the air gap 110 of the second portion 170. The air gap 110 of the first portion 160 is about 0.1% to about 10% smaller than the air gap 110 of the second portion 170. For example, the air gap 110 of the first portion 160 may be about 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, or 10% smaller than the air gap 110 of the second portion 170.

[0093] The first portion 160 coincides with the non-permanent magnet subset 140, and the second portion 170 coincides with the permanent magnet subset 150. Figure 5 As shown, the mixing rotor 104 has two first parts 160 and one second part 170 , wherein the second part 170 is axially arranged between the two first parts 160 .

[0094] In another embodiment, the air gap 110 includes multiple portions with different radial distances. For example, the first portion 160 may overlap with the non-permanent magnet subset 140, with a radial distance of R1 (i.e., 250 mm); the second portion 170 may overlap with the non-permanent magnet subset 150, with a radial distance of R2 (i.e., 225 mm); and the third portion may overlap with the non-permanent magnet subset 140, with a radial distance of R3 (i.e., 238 mm), wherein R1 is greater than R2 and R3, and R3 is greater than R2.

[0095] In another embodiment, the air gap 110 may be uniform, wherein the first portion 160 and the second portion 170 have the same radial distance. Figure 6 As shown, the mixing rotor 104 has two first portions 160 and a second portion 170, wherein the second portion 170 is axially disposed between the two first portions 160. The first portion 160 coincides with the non-permanent magnet subset 140, and the second portion 170 coincides with the permanent magnet subset 150. In other words, the thickness of the air gap 110 can be axially uniform along the length of the mixing rotor. For example, the thickness 160A and 170A of the air gap 110 can be the same, such as Figure 6 shown.

[0096] Figure 7-9 1 is a schematic diagram of a hybrid rotor 104 having various configurations involving a non-permanent magnet subset 140 and a permanent magnet subset 150 according to one or more embodiments of the present disclosure. The non-permanent magnet subset 140 includes a plurality of laminations without magnetic material (e.g., permanent magnets). The permanent magnet subset 150 includes a plurality of laminations with one or more permanent magnets.

[0097] Figure 7 A configuration is shown having a permanent magnet subset 150 disposed between two non-permanent magnet subsets 140. This configuration focuses on optimizing the torque and performance of the electric machine 100 by positioning the permanent magnet subset 150 at the axial core of the hybrid rotor.

[0098] like Figure 7 As shown, the hybrid rotor 104 includes two distal ends axially opposite to each other, each distal end having one of two non-permanent magnet subsets 140. The permanent magnet subset 150 is disposed between the two non-permanent magnet subsets 140. By positioning the permanent magnet subset 150 at the axial core rather than at the distal ends of the hybrid rotor, the leakage flux is reduced; therefore, the interaction of the permanent magnet 154 with the RMF of the stator is increased.

[0099] Additionally, by being positioned at the distal end of the mixing rotor, the non-permanent magnet subset 140 may function as an end plate for the mixing rotor 104 by containing or confining the permanent magnet subset 150; thus reducing the need for end plates.

[0100] Figure 8A configuration is shown having a non-permanent magnet subset 140 disposed between two permanent magnet subsets 150. In this configuration, the non-permanent magnet subset 140 prevents or limits demagnetization of permanent magnets 154 within the hybrid rotor 104 and helps optimize the hybrid rotor's magnet thermal performance.

[0101] During operation of the motor 100, thermal energy (i.e., heat) is concentrated at the center or core of the motor 100. The thermal energy is generated by the electrical load and high frequency operation of the motor 100. If a permanent magnet is located at or near the core of the motor 100, the thermal energy may increase the temperature of the permanent magnet, thereby reducing the strength of the magnetic field emanating from the permanent magnet. If the temperature of the permanent magnet exceeds the Curie temperature of the permanent magnet, the permanent magnet may experience demagnetization. The Curie temperature is the temperature at which a ferromagnetic material (i.e., a permanent magnet) loses its permanent magnetic properties.

[0102] By positioning the non-permanent magnet subset 140 at the core of the hybrid rotor, which is the core of the electric machine 100, the non-permanent magnet subset 140 experiences an increase in temperature rather than the permanent magnet subset 150. By directing thermal energy away from the permanent magnet subset 150, the thermal performance of the hybrid rotor 104 is optimized because the effect of temperature on the permanent magnets 154 is limited by prohibiting the permanent magnets from reaching the Curie temperature.

[0103] Fig. 9 The hybrid rotor 104 is shown having a configuration of a non-permanent magnet subset 140 at the distal ends of the hybrid rotor, with two permanent magnet subsets 150 disposed between the distal ends, and the non-permanent magnet subset 140 disposed between the two permanent magnet subsets 150. This configuration focuses on optimizing the torque and performance of the motor 100 while optimizing the thermal performance of the hybrid rotor.

[0104] like Fig. 9 As shown, the non-permanent magnet subset 140 is positioned at the core of the hybrid rotor 104 and disposed between the permanent magnet subsets 150 because the core of the hybrid rotor 104 experiences the highest temperature during operation of the motor 100. The non-permanent magnet subset 140 absorbs thermal energy and improves the thermal performance of the hybrid rotor. The two permanent magnet subsets 150 optimize the torque and power of the motor 100 because the magnetic torque generated by the permanent magnets 154 provides a higher torque output than the reluctance torque.

[0105] The non-permanent magnet subset 140 combined with the permanent magnet subset 150 reduces the torque ripple experienced by the electric machine 100. The combination of the non-permanent magnet subset 140 and the permanent magnet subset 150 reduces the use of rare earth and heavy rare earth materials while maintaining the performance of the electric machine 100.

[0106] although Figure 7-9Three exemplary configurations are provided, but the present disclosure is not limited to these three configurations. For example, another configuration of the mixing rotor 104 may include a mixing rotor 104 having a permanent magnet subset 150 at the distal ends of the mixing rotor, wherein two non-permanent magnet subsets 140 are disposed between the distal ends, and the permanent magnet subset 150 is disposed between the two non-permanent magnet subsets 140.

[0107] Unless otherwise specified from the context, as used herein, the term "about" should be understood to be within the normal tolerance range in the art, such as within 2 standard deviations of the mean. "About" can be understood to be within 10%, 5%, 1%, 0.5%, 0.1%, 0.05% or 0.01% of the stated value. "About" can alternatively be understood to imply the exact value stated. Unless clearly apparent from the context, the numerical values ​​provided herein are modified by the term "about".

[0108] The terms "comprise", "include" and "have" are inclusive, thus specifying the presence of the features, steps, operations, elements or parts, but not excluding the presence or addition of one or more other features, steps, operations, elements or parts. The order of steps, processes and operations can be changed when possible, and additional or alternative steps can be adopted. As used in this specification, the term "or" includes any one and all combinations of the relevant listed items. The term "any" should be understood to include any possible combination of the referenced items, including "any one" of the referenced items. "One", "an", "the", "at least one" and "one or more" are used interchangeably to indicate that there is at least one item. Unless the context clearly indicates otherwise, there may be multiple such items. Unless otherwise clearly or clearly indicated in the context, including the attached claims, all parameter values ​​(e.g., values ​​of quantities or conditions) should be understood to be modified by the term "about" in all cases, whether or not "about" actually appears before the value. A component that is "configured to" perform a specified function is able to perform the specified function without change, rather than having only the potential to perform the specified function after further modification. In other words, when expressly configured to perform a specified function, the hardware is specifically selected, created, implemented, utilized, programmed, and / or designed for the purpose of performing the specified function.

[0109] Although various embodiments have been described, the description is intended to be exemplary rather than restrictive, and it will be apparent to those of ordinary skill in the art that more embodiments and implementations within the scope of the embodiments are possible. Unless specifically limited, any feature of any embodiment may be used in combination with or replace any other feature or element in any other embodiment. Therefore, the embodiments are not limited except in accordance with the appended claims and their equivalents. Moreover, various modifications and changes may be made within the scope of the appended claims. Although several modes for performing many aspects of the present teachings have been described in detail, those skilled in the art in the field to which these teachings are related will recognize various alternative aspects for practicing the present teachings, which are within the scope of the appended claims. It is intended that all of the contents contained in the above description or shown in the accompanying drawings should be interpreted as illustrative and exemplary of the entire scope of alternative embodiments, and those skilled in the art will recognize that these alternative embodiments are implied by the included content, structurally and / or functionally equivalent to the included content, or become apparent in other ways based on the included content, and should not be limited to only those embodiments that are explicitly depicted and / or described.

Claims

1. A synchronous motor, comprising: a stator comprising a plurality of electrically conductive windings configured to carry an alternating current for generating a rotating magnetic field (RMF); a mixing rotor configured to rotate within the stator according to a torque caused by the RMF, the mixing rotor having a plurality of laminations stacked together axially, wherein the non-permanent magnet subset of the laminations includes one or more through holes configured to limit torque ripple; and Wherein the permanent magnet subset of the laminations comprises one or more pockets, each of the pockets removably retaining one or more permanent magnets operable to magnetically interact with the RMF.

2. The synchronous motor according to claim 1, wherein: The hybrid rotor includes a first non-permanent magnet lamination of the subset of non-permanent magnets at a first distal end and a second non-permanent magnet lamination of the subset of non-permanent magnets at a second distal end axially opposite the first distal end.

3. The synchronous motor according to claim 2, wherein: Each lamination of the permanent magnet subset is disposed between the first distal end and the second distal end.

4. The synchronous motor according to claim 3, wherein: The first permanent magnet lamination of the permanent magnet subset is adjacent to the first non-permanent magnet lamination, the second permanent magnet lamination of the permanent magnet subset is adjacent to the second non-permanent magnet, and the third non-permanent magnet lamination of the non-permanent magnet subset is disposed between the first permanent magnet lamination and the second permanent magnet lamination.

5. The synchronous motor according to claim 1, wherein: The hybrid rotor includes a first permanent magnet lamination of the subset of permanent magnets at a first distal end and a second permanent magnet lamination of the subset of permanent magnets at a second distal end axially opposite the first distal end.

6. The synchronous motor according to claim 5, wherein: Each lamination of the subset of non-permanent magnets is disposed between the first distal end and the second distal end.

7. The synchronous motor according to claim 1, wherein: An air gap separates the mixing rotor from the stator and varies axially along the length of the mixing rotor, and wherein the air gap is defined as the space between the mixing rotor and the stator.

8. The synchronous motor according to claim 7, wherein: A first thickness of the first portion of the air gap is less than a second thickness of the second portion of the air gap.

9. The synchronous motor according to claim 8, wherein: The first portion coincides with the subset of non-permanent magnets and the second portion coincides with the subset of permanent magnets.

10. The synchronous motor according to claim 9, wherein: The second portion is axially disposed between a pair of first portions.

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