Permanent magnet rotor for synchronous reluctance machine

Abstract

The permanent magnet rotor can include a rotor body and at least one magnet. The rotor body can include at least one rotor cavity. The at least one magnet includes in part Mn-Bi particles, and the at least one magnet can be a sintered magnet or a polymer bonded magnet. The at least one magnet can be located at least partially in the at least one rotor cavity. Furthermore, the at least one magnet can be mounted in the at least one rotor cavity after the formation of the at least one magnet, or the at least one magnet can be formed in the at least one rotor cavity using a mold. In addition, the polymer-bonded magnet can include a composite of a polymer matrix and Mn-Bi particles.

Description

Technical Field

[0001] The present disclosure relates to the field of electric machines, and more particularly, to permanent magnet rotors. Background Art

[0002] A synchronous reluctance machine is a machine in which the rotation of the shaft is synchronized with the frequency of the supply current in the steady state. In such a machine, the stator magnetic field rotates with the line current and the rotor rotates at the same speed as the stator magnetic field. Typically, a synchronous reluctance machine uses ferrite or Nd-Fe-B (neodymium) as the magnetic material in the rotor. Ferrites have a lower intrinsic coercivity and are less expensive than other commercially available compounds, however, neodymium-based magnets have an intrinsic coercivity at least twice that of ferrites, so the demagnetization requirements are higher, which can be achieved when ferrites cannot be used. However, the cost of manufacturing a rotor with neodymium-based magnets can be much higher than with ferrites. In addition, although neodymium-based magnetic materials can be diluted with organic binders, this only results in a minor change in cost. Therefore, an improved rotor is desirable. Summary of the invention

[0003] To solve or at least partially solve the above and other potential problems, an embodiment of the present disclosure provides a permanent magnet rotor for a synchronous motor.

[0004] In some embodiments, a permanent magnet rotor comprises a rotor body comprising at least one rotor cavity; and at least one magnet at least partially arranged in the at least one rotor cavity, the at least one magnet comprising: Mn—Bi particles, wherein the Mn—Bi particles form at least a portion of the at least one magnet.

[0005] In some embodiments, at least one magnet comprises a sintered magnet.

[0006] In some embodiments, at least one magnet comprises a polymer-bonded magnet, wherein the polymer-bonded magnet comprises a composite of a polymer matrix and Mn—Bi particles.

[0007] In some embodiments, the polymer matrix comprises a thermoplastic.

[0008] In some embodiments, the polymer matrix includes a thermosetting polymer.

[0009] In some embodiments, the polymer matrix further comprises: an additive, wherein the additive comprises a lubricant, a plasticizer, and a combination of a lubricant and a plasticizer, wherein the additive reduces the polymer melt viscosity to reduce the processing temperature.

[0010] In some embodiments, the rotor body further comprises a plurality of stacked layers, and wherein each stacked layer of the plurality of stacked layers further comprises at least one rotor cavity.

[0011] In some embodiments, the permanent magnet rotor further includes: wherein the melting point of the Mn-Bi particles includes a predetermined temperature; wherein forming at least one magnet includes heating the Mn-Bi particles within a temperature range based at least in part on the predetermined temperature; and wherein the temperature range includes a temperature of 180°C to 280°C.

[0012] In some embodiments, at least one magnet comprises a hard magnetic material having an intrinsic coercivity of at least 400 kA / m.

[0013] In some embodiments, the rotor body comprises a magnetic anisotropy greater than 3.

[0014] In some embodiments, a method for forming a permanent magnet rotor includes obtaining a rotor body comprising at least one rotor cavity; obtaining Mn-Bi particles; forming at least one magnet by applying heat to the Mn-Bi particles within a temperature range based at least in part on a predetermined temperature; and positioning at least one magnet at at least one rotor cavity.

[0015] In some embodiments, the at least one magnet comprises a sintered magnet, and wherein forming the at least one magnet further comprises: applying a magnetic alignment field to Mn—Bi particles; and sintering the Mn—Bi particles within a temperature range to form the at least one magnet.

[0016] In some embodiments, at least one magnet includes a polymer-bonded magnet, and wherein forming the polymer-bonded magnet further comprises: obtaining a polymer matrix; compounding the polymer matrix and Mn-Bi particles to form a composite; obtaining a mold, wherein the mold includes a mold cavity to accommodate a rotor body; positioning the rotor body into the mold cavity; filling at least one rotor cavity with the composite; and applying a magnetic alignment field to the composite before the polymer matrix solidifies.

[0017] In some embodiments, forming the polymer bonded magnet further comprises: applying a magnetizing field to at least one magnet disposed in at least one rotor cavity.

[0018] In some embodiments, the polymer matrix is ​​a thermoplastic.

[0019] In some embodiments, the polymer matrix is ​​a thermosetting polymer.

[0020] In some embodiments, the method further includes: wherein the predetermined temperature includes a melting point of the Mn-Bi particles; wherein forming at least one magnet includes heating the Mn-Bi particles within a temperature range based at least in part on the predetermined temperature; and wherein the temperature range includes a temperature of 180°C to 280°C.

[0021] In some embodiments, the system includes: a rotor body, which includes: a plurality of stacked layers; wherein each of the plurality of stacked layers also includes at least one rotor cavity; and at least one magnet, arranged near at least one rotor cavity, at least one magnet, having a melting point at a predetermined temperature and partially including: Mn-Bi particles; wherein the Mn-Bi particles form at least one magnet by receiving an electromagnetic field within a temperature range at least partially based on the predetermined temperature; wherein the temperature range includes a temperature of 180°C to 280°C.

[0022] In some embodiments, at least one magnet comprises a sintered magnet.

[0023] In some embodiments, at least one magnet comprises a polymer-bonded magnet, wherein at least one magnet comprises a composite of a polymer matrix and Mn—Bi particles. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Some embodiments of the present disclosure are described herein with reference to the accompanying drawings by way of example only. With specific reference now to the accompanying drawings in detail, it is emphasized that the embodiments shown are by way of example and for the purpose of illustrative discussion of the embodiments of the present disclosure. In this regard, the description shown in the accompanying drawings enables those skilled in the art to clearly see how to implement the embodiments of the present disclosure.

[0025] Figure 1 is a top view of a permanent magnet rotor according to some embodiments.

[0026] Figure 2 is a perspective view of a permanent magnet rotor according to some embodiments.

[0027] Figure 3 is a J×H curve of at least one magnet according to some embodiments.

[0028] Figure 4 is a flow chart of a method according to some embodiments.

[0029] Figure 5 is a flow chart of a method according to some embodiments.

[0030] Figure 6 is a flow chart of a method according to some embodiments.

[0031] Figure 7 is a flow chart of a method according to some embodiments. DETAILED DESCRIPTION

[0032] The permanent magnets implemented in the auxiliary synchronous reluctance machine, including ferrite or neodymium-based magnets, preferably have a surplus of at least 30-40% of the air gap flux density to enhance the machine power factor, the resulting current reduction and the improvement of power density. Ferrites have an intrinsic coercive force between 250kA / m and 450kA / m and are relatively low in cost among the commercially available compounds. Since the intrinsic coercive force of neodymium-based magnets is generally greater than that of ferrites, neodymium iron boron magnets can generally be used when there are higher requirements for demagnetization and ferrites cannot be used. However, the cost of neodymium-based magnets is significantly greater than that of ferrites.

[0033] Currently available machines employ either ferrite or neodymium-based magnets in sintered or bonded form in the rotor. The availability of ferrite is thought to reduce material and manufacturing costs for smaller machines. However, while sintered ferrite can be used in magnet-assisted synchronous reluctance machines up to a certain frame size, ferrite may not be a viable option for larger machines due to the lower intrinsic coercivity of ferrite. This results in an increased cost to implement neodymium-based magnets in the rotor.

[0034] Due to magnetic saturation in the laminate material, typical magnet-assisted reluctance motors, induction motors in cast frames, and induction motors in machined frames have nearly similar magnetic loads when the frame size is between 80 mm and 1000 mm, while the air gap flux density is only a fraction of the saturation value. In addition, based on the electrical load of these three motor types, the ferrite coercivity capability will be exceeded in the 250-315 mm frame size range, above which magnets with higher intrinsic coercivity may be required, where the overall magnetic field strength may be proportional to the electrical load of the stator. Therefore, the permanent magnet rotor 100 in this embodiment can provide an alternative for magnet-assisted reluctance motors of different frame sizes.

[0035] Hereinafter, a permanent magnet rotor 100 and a method of forming the permanent magnet rotor 100 relating to various embodiments of the present invention will be described with reference to the accompanying drawings.

[0036] Among those benefits and improvements disclosed, other objects and benefits of the present disclosure will become apparent from the following description in conjunction with the accompanying drawings. Detailed embodiments of the present disclosure are disclosed herein; however, it should be understood that the disclosed embodiments are merely illustrations of the present disclosure that may be embodied in various forms. In addition, each of the various embodiments of the present disclosure given is intended to be illustrative rather than restrictive.

[0037] All prior patents and publications cited herein are incorporated by reference in their entirety.

[0038] Throughout the specification and claims, the following terms have the meanings explicitly associated herein, unless the context clearly dictates otherwise. The phrases "in one embodiment," "in an embodiment," and "in some embodiments" as used herein do not necessarily refer to the same embodiment, although it may. In addition, the phrases "in another embodiment," "in other embodiments," and "in some other embodiments" as used herein do not necessarily refer to different embodiments, although it may. All embodiments of the present disclosure are intended to be combinable without departing from the scope or spirit of the present disclosure.

[0039] As used herein, the term "intrinsic coercivity" can be defined as the resistance of a material to demagnetization. In other words, intrinsic coercivity refers to the strength of the external magnetic field required to demagnetize a magnetic material to saturation under a reverse magnetic field, which can be expressed in Tesla (T) or kA / m.

[0040] As used herein, the term "residual" may be defined as a measure of the magnetization of a magnetic material once it has been exposed to a magnetic field having a magnetization strength sufficient to magnetically saturate the magnet.

[0041] As used herein, the term "based on" is not exclusive and allows for being based on other factors not described unless the context clearly dictates otherwise. In addition, throughout the specification, the meanings of "a," "an," and "the" include plural references. The meaning of "in..." includes "in..." and "on...".

[0042] As used herein, when describing a structural component, the term "between" does not necessarily require being arranged directly next to other elements. Generally speaking, this term refers to a structure in which an object is sandwiched between two or more other objects. At the same time, the word "between" can describe something that is immediately adjacent to two opposite things. Therefore, in any one or more embodiments disclosed herein, a specific structural element arranged between two other structural elements may be:

[0043] being arranged directly between two other structural elements so that the particular structural element is in direct contact with the other two structural elements;

[0044] being arranged directly beside one of the two other structural elements such that the particular structural element is in direct contact with only one of the two other structural elements;

[0045] indirectly disposed beside only one of the two other structural elements, such that the particular structural element is not in direct contact with only one of the two other structural elements, and there is another element juxtaposing the particular structural element with one of the two other structural elements;

[0046] indirectly disposed between two other structural elements, such that a particular structural element is not in direct contact with both other structural elements, and other features may be disposed between them; or

[0047] Any combination thereof.

[0048] Figure 1 1 is a top view of a permanent magnet rotor 100 according to some embodiments. The permanent magnet rotor 100 may be configured to be installed in a synchronous motor. In some embodiments, the permanent magnet rotor 100 may include a rotor body 103 and at least one magnet 105. In some embodiments, the rotor body 103 may be installed in a synchronous motor and may include at least one rotor cavity 109. In some embodiments, at least one magnet 105 may be arranged in at least one rotor cavity 109. In some embodiments, each of the at least one rotor cavity 109 may include the at least one magnet 105. In some embodiments, the number of at least one rotor cavity in the rotor body 103 may exceed the number of at least one magnet 105 in the rotor body 103. In some embodiments, the number of at least one magnet 105 may be based in part on the desired characteristics of the permanent magnet rotor 100, the synchronous motor, other factors, and combinations thereof.

[0049] In some embodiments, the at least one magnet 105 may at least partially include Mn-Bi particles. In some embodiments, at least one magnet 105 may include manganese bismuth particles, organic binders, inorganic binders, antioxidants, fillers, additives, other materials and combinations thereof. In some embodiments, the Mn-Bi particles may at least partially form a magnet powder. In some embodiments, the magnet powder may be diluted with an organic binder, an inorganic binder, a filler, an additive and a combination thereof. In some embodiments, the Mn-Bi particles may be round, rod-shaped, layered or stacked or any irregular structure. In some embodiments, the composition of at least one magnet may vary depending on the application and conditions of use. In some embodiments, at least one magnet 105 may have an intrinsic coercivity comparable to that of a neodymium-based magnet, which will be discussed further below.

[0050] In some embodiments, at least one magnet 105 may be a sintered magnet. In some embodiments, sintering of Mn-Bi particles may include forming at least one magnet 105. In some embodiments, forming at least one magnet 105 may include applying a magnetic alignment field to the Mn-Bi particles and then sintering the Mn-Bi particles to form the body of at least one magnet 105. Therefore, in some embodiments, forming the sintered at least one magnet 105 may include applying an oriented magnetic alignment field to the Mn-Bi particles to orient the Mn-Bi particles before the sintering process. In some embodiments, after orienting and sintering the at least one magnet 105, the at least one magnet 105 may be mounted to the rotor body 103.

[0051] In some embodiments, at least one magnet 105 may be a polymer-bonded magnet. In some embodiments, at least one magnet 105 may include a polymer matrix (i.e., a polymer binder) and Mn-Bi particles. In some embodiments, the polymer matrix and the Mn-Bi particles may be combined to form a composite. At least one magnet 105 may fill at least one rotor cavity 109 by any of a variety of methods of installing at least one magnet into at least one rotor cavity 109. In some embodiments, at least one magnet 105 may be formed by filling at least one rotor cavity 109 with a composite to form at least one magnet 105. In some embodiments, at least one magnet 105 may be formed by obtaining a mold. The interior of the mold may be defined by a mold cavity to accommodate the rotor body 103. The rotor body 103 may be located in the mold cavity so that the composite may fill a void defined at least in part by at least one rotor cavity 109 and at least a portion of the inner surface of the mold cavity. In some embodiments, the composite may fill at least one rotor cavity 109 so that the body of at least one magnet 105 may be defined at least in part by a combination of at least a portion of the surface of at least one rotor cavity 109 and the inner surface of the mold cavity at at least one rotor cavity 109. When the body of the at least one magnet 105 is frozen, the body of the at least one magnet 105 can at least partially assume a shape defined by at least one rotor cavity 109 and at least a portion of the inner surface of the mold cavity. In some embodiments, the body of the at least one magnet 105 can be formed by a combination of the surface of the at least one rotor cavity 109, the inner surface of the mold cavity, and the injection molded closing plate.

[0052] In some embodiments, the directional magnetic alignment field may be applied to the composite during filling of the composite at the at least one rotor cavity 109. In some embodiments, the directional magnetic alignment field may be applied to the composite after the composite has filled the at least one rotor cavity 109 in the mold. In some embodiments, the directional magnetic alignment field may be applied to the composite before the composite freezes and before the temperature of the composite drops below a set temperature (when the magnetic material of the body can no longer be oriented).

[0053] In some embodiments, a magnetic field may be applied to the at least one magnet 105 and the rotor body after the at least one magnet 105 is formed. In some embodiments, a magnetic field may be applied to the rotor body and the mold. In other embodiments, a magnetic field may be applied to the rotor body after the rotor body is removed from the mold. In some embodiments, a magnetic field may be applied to the at least one magnet 105 after the composite has hardened and the at least one magnet 105 is frozen.

[0054] In some embodiments, the polymer matrix can be a thermoplastic matrix. Therefore, in some embodiments, the composite can be a thermoplastic composite. The thermoplastic composite can be formed into at least a portion of at least one magnet 105 by injection molding. In some embodiments, the thermoplastic composite can include, but is not limited to, polyolefins such as polypropylene, polyethylene, low-density polyethylene (LDPE), high-density polyethylene (HDPE), acetal and ketone-based polymers and copolymers, polyesters (e.g., polyethylene terephthalate, polybutylene terephthalate), polycarbonate, polystyrene, polyether sulfone (PESU), polyphenyl sulfone (PPSU), polysulfone, and polytetrafluoroethylene (PTFE). Other polymers can also be implemented, including but not limited to polylactic acid, ethylene vinyl acetate copolymer (EVA), polyvinyl chloride (PVC), polyetherimide (PEI), polyphenylene sulfide (PPS), polyetheretherketone (PEEK), polyphthalamide (PPA), polyoxymethylene (POM), phenolic formaldehyde (PF), unsaturated polyester (UP), polyurethane (PUR and PU), polyimide, polyamide, polyvinyl alcohol, polyvinylidene chloride, polyacrylonitrile and polyalkyl paraben. The polymer matrix can be a single polymer or any combination of these thermoplastics.

[0055] In some embodiments, the polymer matrix can be a thermosetting polymer matrix. Thus, in some embodiments, the thermosetting polymer composite can form at least a portion of at least one magnet 105 by transfer molding, compression molding, potting, and combinations thereof. Thermosetting polymer matrices can include, but are not limited to, epoxy resins, polyesters, bulk molding compounds (BMC), phenolics, polyisoprene, polybutadiene (butadiene rubber), styrene-butadiene rubber, acrylonitrile-butadiene copolymers, isobutylene-isoprene copolymers, ethylene-propylene copolymers, polychloroprene, polysulfide, polydimethylsiloxane (silicone), polyurethane, polyacrylate elastomers, chlorinated polyethylene, styrene-isoprene-styrene copolymers (SIS), styrene-butadiene-styrene copolymers (SBS), ethylene-propylene-diene polymers, and fluoroelastomers, including tetrafluoroethylene propylene, fluorosilicone, and perfluoroelastomers. The polymer matrix can be a single polymer or any combination of these thermosetting polymers.

[0056] In some embodiments, at least one magnet 105 may be formed at least in part by heating Mn-Bi particles. In some embodiments, the Mn-Bi particles may be heated using any of a variety of heating processes, including but not limited to resistive heating, induction heating, friction heating, conduction, convection, radiation, and combinations thereof. In some embodiments, the Mn-Bi particles may have a melting point at a predetermined temperature. In some embodiments, the predetermined temperature may be based in part on a melting point that causes the hard magnetic phase of the Mn-Bi particles to decompose. In some embodiments, the melting point of the Mn-Bi particles may be approximately 260°C. In some embodiments, forming at least one magnet 105 may include heating the Mn-Bi particles within a temperature range based in part on the predetermined temperature. In some embodiments, forming at least one magnet 105 may include heating the Mn-Bi particles within a temperature range of 180°C to 280°C. In some embodiments, forming at least one magnet 105 may include heating the Mn-Bi particles within a temperature range of 200°C to 280°C.

[0057] In some embodiments, the Mn-Bi particles may be mixed with an organic binder, an inorganic binder, other additives, and combinations thereof to increase or decrease the temperature range at which an electromagnetic field may be applied to form at least one magnet 105. In some embodiments, forming at least one magnet 105 may include heating the Mn-Bi particles within a temperature range of 210°C to 280°C. In some embodiments, forming at least one magnet 105 may include heating the Mn-Bi particles within a temperature range of 220°C to 280°C. In some embodiments, forming at least one magnet 105 may include heating the Mn-Bi particles within a temperature range of 230°C to 280°C. In some embodiments, forming at least one magnet 105 may include heating the Mn-Bi particles within a temperature range of 240°C to 280°C. In some embodiments, forming at least one magnet 105 may include heating the Mn-Bi particles within a temperature range of 250°C to 280°C. In some embodiments, forming at least one magnet 105 may include heating the Mn-Bi particles within a temperature range of 260°C to 280°C. In some embodiments, forming at least one magnet 105 may include heating the Mn-Bi particles within a temperature range of 200°C to 270°C. In some embodiments, forming at least one magnet 105 may include heating Mn-Bi particles in a temperature range of 200°C to 260°C. In some embodiments, forming at least one magnet 105 may include heating Mn-Bi particles in a temperature range of 200°C to 250°C. In some embodiments, forming at least one magnet 105 may include heating Mn-Bi particles in a temperature range of 200°C to 240°C. In some embodiments, forming at least one magnet 105 may include heating Mn-Bi particles in a temperature range of 200°C to 230°C. In some embodiments, forming at least one magnet 105 may include heating Mn-Bi particles in a temperature range of 200°C to 220°C.

[0058] In some embodiments, the polymer matrix may be sensitive to temperature and oxidation. Therefore, in some embodiments, the polymer matrix may include additives to reduce the viscosity of the polymer melt, thereby reducing the processing temperature when forming at least one magnet 105. In some embodiments, the additive may be a lubricant, a plasticizer, an antioxidant, other reagents and combinations thereof. In some embodiments, the plasticizer additive can effectively reduce the mixing and molding temperature of thermoplastics, and may include di-n-butyl phthalate, tripolypropyl phosphate, tripropyl phosphate, diisooctyl adipate, isooctyl ester, epoxidized soybean oil and sebacic acid polypropylene. In some embodiments, the additive may include an antioxidant to reduce oxidation in the polymer matrix and manganese-bismuth particles. In some embodiments, the antioxidant may include hindered phenols, phosphites / phosphites, sulfur synergists, metal deactivators, any antioxidant mixtures and combinations thereof.

[0059] In some embodiments, the rotor body 103 may include at least one rotor cavity 109. In some embodiments, the number and location of the at least one rotor cavity 109 in the rotor body 103 may be based in part on any of a number of features, including but not limited to rotor topology, rotor size, motor size, power rating, stator design, other features, and combinations thereof. In some embodiments, the depth of the at least one rotor cavity 109 may be based at least in part on the desired rotor layout, the size of the at least one magnet 105, other factors, and combinations thereof. In some embodiments, the at least one rotor cavity 109 may extend radially along the rotor body 103. In some embodiments, the at least one rotor cavity 109 may extend axially along the rotor body 103. In some embodiments, the at least one rotor cavity 109 may include but not limited to grooves, channels, holes, holes, other contours, and combinations thereof, wherein the at least one rotor cavity 109 is at least partially defined by the rotor body 103. In some embodiments, the at least one rotor cavity 109 may be arranged in the rotor body 103, and the boundary of the at least one rotor cavity 109 is substantially defined by the rotor body 103. In addition, in some embodiments, the at least one rotor cavity 109 may include a variety of shapes, including but not limited to circular, rounded, angular, linear, and any combination thereof. For example, in some embodiments, at least one rotor cavity 109 may be axially arranged on the surface 111 of the rotor body 103, and at least one rotor cavity 109 has at least one magnet 105 arranged in the at least one rotor cavity 109, so that the at least one magnet 105 does not protrude beyond the surface 111 of the rotor body 103.

[0060] In some embodiments, the shape of the at least one magnet 105 may be complementary to the at least one rotor cavity 109. In some embodiments, the at least one magnet 105 may include any of a variety of shapes independent of the at least one rotor cavity 109. In some embodiments, the at least one magnet 105 may be completely disposed in the at least one rotor cavity 109, wherein no portion of the at least one magnet 105 protrudes beyond the surface of the rotor body 103. In some embodiments, the at least one magnet 105 may at least partially protrude from the at least one rotor cavity 109. In some embodiments, the at least one magnet 105 may be formed prior to being mounted on the rotor body 103, and the at least one magnet 105 may be attached to the rotor body 103 by adhesive, epoxy, adhesive, and combinations thereof. In some embodiments, the at least one magnet 105 may be partially formed by inserting into the at least one rotor cavity 109 and allowed to partially harden or fully harden in the at least one rotor cavity 109. In some embodiments, the shape of the at least one magnet 105 may be based in part on the shape of the at least one rotor cavity 109. In some embodiments, the at least one magnet 105 may be shaped such that when the at least one magnet 105 is installed in the rotor body 103, the surface of the at least one magnet 105 does not extend beyond the surface of the rotor body 103. In some embodiments, the at least one magnet 105 may extend beyond the surface of the rotor body 103 and the contour of the at least one rotor cavity 109. For example, but not limited to, when the polymer matrix of the at least one magnet 105 is formed in a mold containing the rotor body 103, the contour of the at least one magnet 105 may be based on a combination of the at least one rotor cavity 109 and the at least one mold cavity.

[0061] In some embodiments, the rotor body 103 may include a plurality of poles 133. Note that the number and position of each of the plurality of poles 133 shown in the exemplary embodiment are exemplary and non-restrictive. In some embodiments, the rotor body 103 may include at least two poles. In some embodiments, the rotor body 103 may include four poles. In some embodiments, the rotor body 103 may include six poles. In some embodiments, the rotor body 103 may include eight poles. In some embodiments, the rotor body 103 may include more than eight poles. In some embodiments, the rotor body 103 may include ten poles. In some embodiments, the rotor body 103 may include twelve poles. In some embodiments, the rotor body 103 may include fourteen poles. In some embodiments, the rotor body 103 may include up to twenty-four poles. In some embodiments, the rotor body 103 may include more than twenty-four poles.

[0062] Figure 21 is a perspective view of a permanent magnet rotor 100 according to some embodiments. The permanent magnet rotor 100 shown in the figure is an exemplary embodiment and is not limiting. In some embodiments, the rotor body 103 may include a stacked layer 131. In some embodiments, the rotor body 103 may include a plurality of stacked layers 131. In some embodiments, the number of stacked layers 131 may be based on multiple factors, including but not limited to rotor topology, motor design, power requirements, stator design, air gap, other operating characteristics, and combinations thereof.

[0063] In some embodiments, each stacked layer 131 may include at least one rotor cavity 109. In some embodiments, each stacked layer 131 may include the same number of rotor cavities 109, a different number of rotor cavities 109, and combinations thereof. In some embodiments, the position of each of the at least one rotor cavity 109 may be based in part on the number of poles desired in the rotor body 103. Thus, each stacked layer 131 may include a plurality of poles 133 defined in part by the position of the rotor cavities 109.

[0064] In some embodiments, the rotor body 103 may include a hole 135 extending axially through a central portion of the rotor body 103. In some embodiments, the hole 135 may extend through each stacked layer 131 that may form the rotor body 103. In some embodiments, the hole 135 may accommodate a rotor shaft, other components, and combinations thereof.

[0065] The rotor body 103 can be any of a variety of rotor diameters, based at least in part on the size of the motor, the power rating of the motor, the air gap, the air gap flux density, other design and operating characteristics, and combinations thereof. In some embodiments, the rotor diameter can be up to 3000 mm. In some embodiments, the rotor diameter can be in the range of 200 mm to 3000 mm. In some embodiments, the rotor diameter can be in the range of 400 mm to 3000 mm. In some embodiments, the rotor diameter can be in the range of 500 mm to 3000 mm. In some embodiments, in some embodiments, the rotor diameter can be in the range of 1500 mm to 3000 mm. In some embodiments, the rotor diameter can be in the range of 2000 mm to 3000 mm. In some embodiments, the rotor diameter can be in the range of 2500 mm to 3000 mm.

[0066] In some embodiments, at least one magnet 105 may include a residual magnetism of 30-80% of the air gap flux density. In some embodiments, the permanent magnet rotor 100 may include a residual magnetism of 40-80% of the air gap flux density. In some embodiments, the permanent magnet rotor 100 may include a residual magnetism of 50-80% of the air gap flux density. In some embodiments, the permanent magnet rotor 100 may include a residual magnetism of 30-70% of the air gap flux density. In some embodiments, the permanent magnet rotor 100 may include a residual magnetism of 30-60% of the air gap flux density. In some embodiments, the permanent magnet rotor 100 may include a residual magnetism of 30-50% of the air gap flux density.

[0067] Figure 3 is a J×H curve 300 of at least one magnet 105 formed of a polymer matrix and manganese-bismuth particles according to some embodiments. Note that Figure 3 The J×H curve 300 shown in is an illustrative embodiment of the at least one magnet 105 and is not limiting. In some embodiments, the intrinsic coercivity of the at least one magnet 105 can be at least 400 kA / m. In some embodiments, the intrinsic coercivity of the at least one magnet 105 can be at least 500 kA / m. In some embodiments, the intrinsic coercivity of the at least one magnet 105 can be at least 700 kA / m. In some embodiments, the intrinsic coercivity of the at least one magnet 105 can be at least 1000 kA / m. In some embodiments, the intrinsic coercivity of the at least one magnet 105 can be as high as 1200 kA / m.

[0068] In some embodiments, a directional magnetic alignment field may be applied to the body of at least one magnet 105 to partially form at least one magnet 105. The directional magnetic alignment field used to generate magnetic anisotropy should be high enough to drive the magnetic material to saturation. In some embodiments, the directional magnetic alignment field applied to at least one magnet 105 to drive at least one magnet 105 to saturation may be greater than the directional magnetic alignment field of ferrites, but less than the directional magnetic alignment field of neodymium-based magnets. In some embodiments, the body of at least one magnet 105 may be magnetically saturated by a magnetic alignment field of 1-2T. In some embodiments, the body of at least one magnet 105 may be magnetically saturated by a magnetic alignment field of 2T or greater to fully saturate at least one magnet 105.

[0069] In some embodiments, after positioning the at least one magnet 105 in the at least one rotor cavity 109, a magnetizing field may be applied to the body of the at least one magnet 105. In some embodiments, after the body of the at least one magnet 105 is solidified at the at least one rotor cavity 109, a magnetizing field may be applied to the body of the at least one magnet 105. In some embodiments, the magnetizing field applied to the at least one magnet 105 may be 1T to 2T. In some embodiments, the magnetizing field applied to the at least one magnet 105 may be 2T to 3T. In some embodiments, the magnetizing field may be at least 3T.

[0070] Figure 4-7 is a flow chart of a method 400 according to some embodiments. The method 400 generally involves forming a permanent magnet rotor 100 .

[0071] refer to Figure 4 , at 410, method 400 includes obtaining a rotor body 103. The rotor body 103 may include at least one rotor cavity 109, which is arranged on the rotor body 103 to accommodate at least one magnet 105. At 420, method 400 includes obtaining Mn-Bi particles. In some embodiments, the Mn-Bi particles may be magnetic powder. At 430, method 400 includes forming at least one magnet 105. In some embodiments, forming at least one magnet 105 may include heating the Mn-Bi particles. In some embodiments, the Mn-Bi particles may be heated at or within a temperature range. In some embodiments, the temperature range may be based at least in part on a predetermined temperature. In some embodiments, the predetermined temperature may be a melting point that causes decomposition of the hard magnetic phase of the Mn-Bi particles.

[0072] At 440, the method 400 includes positioning the at least one magnet 105 at the at least one rotor cavity 109. In some embodiments, the body of the at least one magnet 105 can be formed before positioning the at least one magnet 105 at the at least one rotor cavity 109. In some embodiments, the body of the at least one magnet 105 can be formed during positioning the at least one magnet 105 at the at least one rotor cavity 109.

[0073] refer to Figure 5 In some embodiments, at least one magnet 105 may be a sintered magnet. In some embodiments, at 510, forming at least one magnet 105 may include applying a magnetic alignment field to the Mn-Bi particles. The magnetic alignment field may orient the Mn-Bi particles while forming the at least one magnet 105. In some embodiments, at 520, forming at least one magnet 105 may include sintering the Mn-Bi particles within the temperature range to form a body of the at least one magnet 105. Sintering the at least one magnet 105 may harden the magnetic material to form a body of the at least one magnet 105.

[0074] refer to Figure 6 , in some embodiments, at least one magnet 105 may be a polymer bonded magnet. In some embodiments, at 610, forming at least one magnet 105 may include obtaining a polymer matrix. The polymer matrix may be a polymer adhesive. In some embodiments, at 620, forming at least one magnet 105 may include mixing the polymer matrix and Mn-Bi particles to form a composite. In some embodiments, at 630, forming at least one magnet 105 may include obtaining a mold. The mold may include a mold cavity. In some embodiments, the shape of the mold cavity may be the shape and size of the rotor body. In some embodiments, the mold cavity may be substantially the shape of the rotor body to allow the composite to be filled into the at least one rotor cavity 109. In some embodiments, at 640, forming at least one magnet 105 may include positioning the rotor body in the mold cavity. In some embodiments, at 650, forming at least one magnet 105 may include filling at least one rotor cavity 109 with the composite. In some embodiments, filling at least one rotor cavity 109 may include filling the mold cavity so that the composite can be introduced into the at least one rotor cavity 109.

[0075] In some embodiments, at 660, forming at least one magnet 105 may include applying a magnetic alignment field to the composite. In some embodiments, the magnetic alignment field may be applied to the composite when the temperature of the composite is close to the filling temperature. In some embodiments, the magnetic alignment field may be applied to the composite before the composite solidifies. In some embodiments, the magnetic alignment field may be applied when the composite fills at least one rotor cavity 109. In some embodiments, the magnetic alignment field may be applied to the composite once the composite fills at least one rotor cavity 109 and before the composite cools. In some embodiments, the magnetic alignment field may be applied to the composite before the composite cools below a set temperature. The composite receives the magnetic alignment field before solidification, otherwise the Mn-Bi particles may be mechanically locked and the orientation of the Mn-Bi particles may be disturbed. In some embodiments, the magnetic alignment field applied to the body of the at least one magnet 105 may be 1T to 2T. In some embodiments, the magnetic alignment field applied to the body of the at least one magnet 105 may be 2T to 3T. In some embodiments, the magnetic alignment field applied to the body of the at least one magnet 105 may be greater than 3T.

[0076] refer to Figure 7 In some embodiments, at 710, forming at least one magnet 105 may further include applying a magnetizing field to at least one magnet 105 disposed in at least one rotor cavity 109. In some embodiments, at 660 ( Figure 6), the magnetic alignment field may be a first magnetizing field, and the magnetizing field may be a second magnetic field applied to the at least one magnet 105 after the at least one magnet 105 is solidified in the at least one rotor cavity 109. In some embodiments, the magnetizing field applied to the body of the at least one magnet 105 may be in the range of 1T to 2T. In some embodiments, the magnetizing field applied to the body of the at least one magnet 105 may be in the range of 2T to 3T.

[0077] aspect

[0078] Various aspects are described below. It should be understood that any one or more features described in the following aspects may be combined with any one or more other aspects.

[0079] In some aspects, the technology described herein relates to a permanent magnet rotor, comprising: a rotor body, comprising: at least one rotor cavity; and at least one magnet, at least partially arranged in the at least one rotor cavity, the at least one magnet comprising: Mn-Bi particles, wherein the Mn-Bi particles form at least a portion of the at least one magnet.

[0080] In some aspects, the technology described herein relates to a permanent magnet rotor in which at least one magnet comprises a sintered magnet.

[0081] In some aspects, the technology described herein relates to a permanent magnet rotor, wherein at least one magnet comprises a polymer bonded magnet, wherein the polymer bonded magnet comprises a composite of a polymer matrix and Mn—Bi particles.

[0082] In some aspects, the technology described herein relates to a permanent magnet rotor wherein the polymer matrix comprises a thermoplastic.

[0083] In some aspects, the technology described herein relates to a permanent magnet rotor wherein the polymer matrix comprises a thermoset polymer.

[0084] In some aspects, the technology described herein relates to a permanent magnet rotor, wherein the polymer matrix further comprises: an additive, wherein the additive comprises a lubricant, a plasticizer, and a combination of a lubricant and a plasticizer, wherein the additive reduces polymer melt viscosity to reduce processing temperature.

[0085] In some aspects, the technology described herein relates to a permanent magnet rotor, wherein the rotor body further comprises a plurality of stacked layers, and wherein each stacked layer of the plurality of stacked layers further comprises at least one rotor cavity.

[0086] In some aspects, the technology described herein relates to a permanent magnet rotor, further comprising: wherein the melting point of the Mn-Bi particles comprises a predetermined temperature; wherein forming at least one magnet comprises heating the Mn-Bi particles within a temperature range based at least in part on the predetermined temperature; and wherein the temperature range comprises a temperature of 180°C to 280°C.

[0087] In some aspects, the technology described herein relates to a permanent magnet rotor in which at least one magnet comprises a hard magnetic material having an intrinsic coercivity of at least 400 kA / m.

[0088] In some aspects, the technology described herein relates to a permanent magnet rotor wherein the rotor body comprises a magnetic anisotropy greater than 3.

[0089] In some aspects, the technology described herein relates to a method for forming a permanent magnet rotor, comprising: obtaining a rotor body, the rotor body comprising at least one rotor cavity; obtaining Mn-Bi particles; forming at least one magnet by applying heat to the Mn-Bi particles within a temperature range based at least in part on a predetermined temperature; and positioning at least one magnet at at least one rotor cavity.

[0090] In some aspects, the technology described herein relates to a method wherein at least one magnet comprises a sintered magnet, and wherein forming the at least one magnet further comprises: applying a magnetic alignment field to Mn—Bi particles; and sintering the Mn—Bi particles within a temperature range to form the at least one magnet.

[0091] In some aspects, the technology described herein relates to a method wherein at least one magnet comprises a polymer-bonded magnet, and wherein forming the polymer-bonded magnet further comprises: obtaining a polymer matrix; compounding the polymer matrix and Mn-Bi particles to form a composite; obtaining a mold, wherein the mold comprises a mold cavity to accommodate a rotor body; positioning the rotor body into the mold cavity; filling at least one rotor cavity with the composite; and applying a magnetic alignment field to the composite before the polymer matrix solidifies.

[0092] In some aspects, the technology described herein relates to a method wherein forming the polymer-bonded magnet further comprises applying a magnetizing field to at least one magnet disposed in at least one rotor cavity.

[0093] In some aspects, the technology described herein relates to methods wherein the polymer matrix is ​​a thermoplastic.

[0094] In some aspects, the technology described herein relates to methods wherein the polymer matrix is ​​a thermoset polymer.

[0095] In some aspects, the technology described herein relates to a method, further comprising: wherein the predetermined temperature includes a melting point of the Mn-Bi particles; wherein forming at least one magnet includes heating the Mn-Bi particles within a temperature range based at least in part on the predetermined temperature; and wherein the temperature range includes a temperature of 180°C to 280°C.

[0096] In some aspects, the technology described herein relates to a system, comprising: a rotor body, comprising: a plurality of stacked layers; wherein each of the plurality of stacked layers further comprises at least one rotor cavity; and at least one magnet, arranged proximate to the at least one rotor cavity, the at least one magnet having a melting point at a predetermined temperature and comprising, in part: Mn-Bi particles; wherein the Mn-Bi particles form at least one magnet by receiving an electromagnetic field within a temperature range at least partially based on the predetermined temperature; wherein the temperature range comprises a temperature of 180°C to 280°C.

[0097] In some aspects, the technology described herein relates to a system wherein at least one magnet comprises a sintered magnet.

[0098] In some aspects, the technology described herein relates to a system wherein at least one magnet comprises a polymer-bonded magnet, wherein at least one magnet comprises a composite of a polymer matrix and Mn—Bi particles.

[0099] It should be understood that changes may be made in detail, especially in the materials of construction employed and the shapes, sizes, and arrangements of parts without departing from the scope of the present disclosure. The specification and described embodiments are examples, with the true scope and spirit of the present disclosure being indicated by the appended claims.

Claims

1. A permanent magnet rotor, comprising: The rotor body comprises: at least one rotor chamber; and at least one magnet disposed at least partially in the at least one rotor cavity, the at least one magnet comprising: Mn-Bi particles, wherein the Mn—Bi particles form at least a portion of the at least one magnet. 2 . The permanent magnet rotor of claim 1 , wherein the at least one magnet comprises a sintered magnet.

3. The permanent magnet rotor of claim 1 , wherein the at least one magnet comprises a polymer bonded magnet, The polymer-bonded magnet comprises a composite of a polymer matrix and the Mn-Bi particles.

4. The permanent magnet rotor of claim 3, wherein the polymer matrix comprises a thermoplastic.

5. The permanent magnet rotor of claim 3, wherein the polymer matrix comprises a thermosetting polymer.

6. The permanent magnet rotor of claim 3, wherein the polymer matrix further comprises: additive, The additives include lubricants, plasticizers, and combinations of the lubricants and plasticizers. The additives reduce the polymer melt viscosity to lower the processing temperature. 7 . The permanent magnet rotor of claim 1 , wherein the rotor body further comprises a plurality of stacked layers, and wherein each of the plurality of stacked layers further comprises the at least one rotor cavity.

8. The permanent magnet rotor according to claim 1, further comprising: wherein the melting point of the Mn-Bi particles comprises a predetermined temperature; wherein forming the at least one magnet comprises heating the Mn—Bi particles within a temperature range based at least in part on the predetermined temperature; and The temperature range includes temperatures from 180°C to 280°C.

9. The permanent magnet rotor of claim 1, wherein the at least one magnet comprises a hard magnetic material having an intrinsic coercivity of at least 400 kA / m.

10. The permanent magnet rotor of claim 1, wherein the rotor body comprises a magnetic anisotropy greater than 3.

11. A method for forming a permanent magnet rotor, comprising: Obtaining a rotor body, wherein the rotor body comprises at least one rotor cavity; Obtaining Mn-Bi particles; forming at least one magnet by applying heat to the Mn—Bi particles within a temperature range based at least in part on a predetermined temperature; and The at least one magnet is positioned at the at least one rotor cavity.

12. The method of claim 11, wherein the at least one magnet comprises a sintered magnet, and wherein forming the at least one magnet further comprises: applying a magnetic alignment field to the Mn-Bi particles; as well as The Mn—Bi particles are sintered within the temperature range to form the at least one magnet.

13. The method of claim 11, wherein the at least one magnet comprises a polymer-bonded magnet, and wherein forming the polymer-bonded magnet further comprises: obtaining a polymer matrix; Compounding the polymer matrix and the Mn-Bi particles to form a composite; Get the mold, wherein the mold comprises a mold cavity to accommodate the rotor body; positioning the rotor body into the mold cavity; filling the at least one rotor cavity with the composite; and A magnetic alignment field is applied to the composite prior to solidification of the polymer matrix.

14. The method of claim 13, wherein forming the polymer-bonded magnet further comprises: A magnetizing field is applied to the at least one magnet disposed in the at least one rotor cavity.

15. The method of claim 13, wherein the polymer matrix is ​​a thermoplastic.

16. The method of claim 13, wherein the polymer matrix is ​​a thermosetting polymer.

17. The method according to claim 11, further comprising: wherein the predetermined temperature includes the melting point of the Mn-Bi particles; wherein forming the at least one magnet comprises applying heat to the Mn—Bi particles within a temperature range based at least in part on the predetermined temperature; and The temperature range includes temperatures from 180°C to 280°C.

18. A system comprising: The rotor body comprises: Multiple stacked layers; wherein each stacked layer in the plurality of stacked layers further comprises at least one rotor cavity; and at least one magnet disposed proximate to the at least one rotor cavity, the at least one magnet having a melting point at a predetermined temperature and comprising, in part: Mn-Bi particles; wherein the Mn—Bi particles form the at least one magnet by receiving an electromagnetic field within a temperature range based at least in part on the predetermined temperature; The temperature range includes temperatures from 180°C to 280°C.

19. The system of claim 18, wherein the at least one magnet comprises a sintered magnet.

20. The system of claim 18, wherein the at least one magnet comprises a polymer-bonded magnet, Wherein the at least one magnet comprises a composite of a polymer matrix and the Mn—Bi particles.

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