Rotating electric machine having rotor comprising low coertial and high

Abstract

A rotor for a rotary electric machine includes a ring-shaped stacked rotor lamination layers ("root lams") constructed from a magnetic core material. The rotor lamination layers include inner axial surfaces that collectively define a first plurality of openings through the magnetic core material, a second plurality of openings through the magnetic core material, and a third plurality of openings through the magnetic core material. Each respective one of the first plurality of permanent magnets, the second plurality of permanent magnets, and the third plurality of permanent magnets is disposed within a respective one of the first plurality of openings, the second plurality of openings, and the third plurality of openings, respectively. The first plurality of permanent magnets and the third plurality of permanent magnets include high-coercivity magnets. The second plurality of permanent magnets includes a low-coercivity magnet.

Description

Technical Field

[0001] The present invention relates to a rotating electric machine having a rotor including both a low coercivity and a high coercivity magnet. Background Art

[0002] A rotating electric machine of a type used in an electric drive system operates in an electric mode, in which an output torque is transmitted to a coupled load, such as one or more wheels of a motor vehicle, and / or in a power generation mode, in which the machine rotates for power generation. In a typical configuration, the electric machine includes a cylindrical rotor formed by annularly stacked thin magnetic rotor laminations or "rotor lams". The magnetic material of the rotor laminations is typically an alloy of iron and silicon, commonly referred to in the art as electrical steel.

[0003] Permanent magnets, such as but not limited to rare earth magnets, such as neodymium (Nd) magnets, also known as NdFeB, NIB or Neo magnets, are disposed within openings or slots in the rotor to generate an electric machine magnetic flux having a magnetic flux field along a predefined path, which can be enhanced and / or opposed. Enhancing the magnetic flux field increases the torque generation of the electric machine, while opposing the magnetic flux field will limit the torque generation of the electric machine. The configuration or topology of the permanent magnets disposed within the rotor determines the power density of the electric machine.

[0004] Neodymium magnets are rare earth magnets made of an alloy of neodymium (Nd), iron (Fe) and boron (B). Nd magnets have a high coercivity, i.e., resistance to demagnetization, and a high magnetic energy density (BH max ). Reducing the amount of rare earth elements used in the electric machine can improve sustainability. Summary of the Invention

[0005] Accordingly, disclosed herein are a rotating electric machine and a rotor having both high coercivity permanent magnets and low coercivity permanent magnets configured in parallel within a three-level topology, where each level is a magnetic flux barrier.

[0006] The high coercivity permanent magnets can include rare earth magnets, such as but not limited to neodymium (Nd) magnets and / or samarium (Sm) magnets, while the low coercivity magnets can include, for example but not limited to, ferrite, aluminum, nickel and cobalt ("Alinco") and / or ceramic magnets, which include less than about 10% by weight of rare earth elements and / or less than about 1% by weight of heavy rare earth materials, such as but not limited to Nd, terbium (Tb) and / or dysprosium (Dy). The combination of high coercivity permanent magnets and low coercivity permanent magnets reduces the use of rare earth elements in the electric machine and improves sustainability.

[0007] The strategic arrangement of three flux barriers within the rotor can enhance the torque performance of the motor while ensuring the smooth passage of the magnetic field. Additionally, the position and distribution of two types of permanent magnets disposed within each flux barrier can further enhance the torque performance of the motor while providing robustness against demagnetization and minimizing cross-demagnetization.

[0008] In addition, permanent magnets having rectangular and / or curved shapes are disclosed.

[0009] A rotor for a rotating electric machine can include an annular stack of rotor laminations (“rotor lams”) constructed of a magnetic core material. Each rotor lamination can have an inner axial surface or lamination wall that together define a first plurality of openings through the magnetic core material, a second plurality of openings through the magnetic core material, and a third plurality of openings through the magnetic core material.

[0010] Each rotor can include a first plurality of permanent magnets, with each respective one of the first plurality of permanent magnets disposed within a corresponding one of the first plurality of openings. The first plurality of permanent magnets can include high coercivity magnets, such as but not limited to rare earth magnets, such as neodymium (Nd) magnets or samarium (Sm) magnets.

[0011] Each rotor can include a second plurality of permanent magnets, with each respective one of the second plurality of permanent magnets disposed within a corresponding one of the second plurality of openings. The second plurality of permanent magnets can include low coercivity magnets, such as but not limited to ferrite magnets, and / or other magnets including less than about 10% rare earth elements by weight and / or less than about 1% heavy rare earth elements by weight.

[0012] Each rotor can include a third plurality of permanent magnets, with each respective one of the third plurality of permanent magnets disposed within a corresponding one of the third plurality of openings. The third plurality of permanent magnets can include high coercivity magnets, such as but not limited to rare earth magnets, such as neodymium (Nd) magnets or samarium (Sm) magnets.

[0013] The first plurality of permanent magnets can be arranged in a first stacked configuration. Each of the first plurality of permanent magnets can have parallel magnetization.

[0014] The second plurality of permanent magnets can be arranged in a second stacked configuration. Each of the second plurality of permanent magnets can have parallel magnetization.

[0015] The second plurality of permanent magnets can include curved magnets having radial magnetization.

[0016] According to one aspect of the present disclosure, at least one of the second plurality of openings includes a double-ridge profile.

[0017] According to one aspect of the present disclosure, at least one of the curved magnets can include a polymer support layer between at least one of the curved magnets and a corresponding one of the second plurality of openings.

[0018] According to one aspect of the present disclosure, each of the second plurality of permanent magnets may be adhesively bonded to the annularly stacked rotor laminations.

[0019] The third plurality of permanent magnets may be arranged in a third stacked configuration. Each of the third plurality of permanent magnets may have parallel magnetization.

[0020] According to one aspect of the present disclosure, each of the first plurality of permanent magnets and each of the third plurality of permanent magnets may have a rectangular configuration.

[0021] According to one aspect of the present disclosure, the first plurality of permanent magnets and the third plurality of permanent magnets may include rare earth magnets. The second plurality of permanent magnets may include ferrite magnets and / or other magnets including less than about 10% by weight of rare earth elements and / or less than about 1% by weight of heavy rare earth elements.

[0022] The height of at least one ferrite magnet may be greater than the height of at least one rare earth magnet.

[0023] According to one aspect of the present disclosure, at least some of the first plurality of openings, the plurality of second openings, and the plurality of third openings may define one or more cooling channels therethrough at positions adjacent to at least some of the first plurality of magnets, the second plurality of permanent magnets, and the third plurality of permanent magnets.

[0024] According to another aspect of the present disclosure, the rotor may include a three-layer topology including a first flux barrier, a second flux barrier, and a third flux barrier.

[0025] The first flux barrier may be composed of a first magnet of the first plurality of permanent magnets, a first magnet of the second plurality of permanent magnets, and a first magnet of the third plurality of permanent magnets.

[0026] The second flux barrier may be composed of a second magnet of the first plurality of permanent magnets, a second magnet of the second plurality of magnets, and a second magnet of the third plurality of magnets.

[0027] The third flux barrier may be composed of a third magnet of the first plurality of permanent magnets, a third magnet of the second plurality of permanent magnets, and a third magnet of the third plurality of permanent magnets.

[0028] According to another aspect of the present disclosure, the rotor may include a first radial web and a second radial web. The first radial web may be disposed between the first plurality of permanent magnets and the second plurality of permanent magnets. The second radial web may be disposed between the second plurality of permanent magnets and the third plurality of permanent magnets.

[0029] The first plurality of permanent magnets and the third plurality of permanent magnets may include rare earth magnets, while the second plurality of permanent magnets may include ferrite magnets and / or other magnets comprising less than about 10% by weight of rare earth elements and / or less than about 1% by weight of heavy rare earth elements.

[0030] According to another aspect of the present disclosure, a rotating electric machine may include a stator and a rotor having an annular stack of laminated sheets (“rotor laminations”) or flux barriers surrounded by the stator. The annular stack of rotor laminations may be made of a core material. The annular stack of rotor laminations may have an outer diameter surface and an inner diameter surface defining a plurality of openings through the core material.

[0031] Each rotor may include a set of permanent magnets disposed in the openings within an annular stack in a three-layer topology. Each of the three layers may contain at least three permanent magnets.

[0032] The three layers may include a first layer adjacent to the outer diameter surface, a second layer adjacent to the first layer, and a third layer adjacent to the inner diameter surface.

[0033] The set of permanent magnets may include (i) a plurality of low coercivity permanent magnets, and (ii) a plurality of high coercivity permanent magnets adjacent to the low coercivity permanent magnets. The plurality of low coercivity permanent magnets may be separated from the plurality of high coercivity permanent magnets by one or more radial webs of the core material.

[0034] According to one aspect of the present disclosure, at least one of the three layers may include at least one of the plurality of low coercivity permanent magnets disposed on each side of one of the one or more radial webs of the core material.

[0035] The low coercivity magnets may include, for example but not limited to, ferrite magnets and / or other magnets comprising less than about 10% by weight of rare earth elements and / or less than about 1% by weight of heavy rare earth elements. The high coercivity magnets may include, for example but not limited to, rare earth magnets such as Nd or Sm magnets.

[0036] According to another aspect of the present disclosure, an electric vehicle may include an electric drive system that includes a rotating electric machine configured to be coupled to one or more wheels disposed on a drive shaft, a battery pack electrically connected to the rotating electric machine, and a controller configured to control the rotating electric machine.

[0037] The rotor may include a first plurality of permanent magnets, each of the first plurality of permanent magnets being disposed within a corresponding one of the first plurality of openings. The first plurality of permanent magnets includes high coercivity magnets such as, for example but not limited to, rare earth magnets such as Nd magnets or samarium (Sm) magnets.

[0038] The rotor may include a second plurality of permanent magnets, with each of the second plurality of permanent magnets disposed within a corresponding one of the second plurality of openings. The second plurality of permanent magnets includes low coercivity magnets, such as but not limited to ferrite magnets, and / or other magnets including less than about 10% rare earth elements by weight and / or less than about 1% heavy rare earth elements by weight.

[0039] The rotor may include a third plurality of permanent magnets, with each of the third plurality of permanent magnets disposed within a corresponding one of the third plurality of openings. The third plurality of permanent magnets includes high coercivity magnets, such as but not limited to rare earth magnets, such as Nd or Sm magnets.

[0040] According to another aspect of the present disclosure, the first plurality of permanent magnets may be arranged in a first stacked configuration. Each of the first plurality of permanent magnets may have parallel magnetization.

[0041] The second plurality of permanent magnets may be arranged in a second stacked configuration. Each of the second plurality of permanent magnets may have parallel magnetization or radial magnetization.

[0042] The third plurality of permanent magnets may be arranged in a third stacked configuration. Each of the third plurality of permanent magnets may have parallel magnetization.

[0043] According to one aspect of the present disclosure, the first plurality of permanent magnets and the third plurality of permanent magnets may include rare earth magnets. The second plurality of permanent magnets may include ferrite magnets and / or other magnets including less than about 10% rare earth elements by weight and / or less than about 1% heavy rare earth materials by weight.

[0044] Alternatively, an electric vehicle may include an electric drive system that includes a rotating electric machine configured to be coupled to one or more wheels disposed on a drive shaft, a battery pack electrically connected to the rotating electric machine, and a controller configured to control the rotating electric machine.

[0045] The rotating electric machine may include a stator and a rotor having an annular stacked lamination (a "rotor lamination") or a flux barrier surrounded by the stator. The annular stacked rotor lamination may be composed of a magnetic core material. The annular stacked rotor lamination may have an outer diameter surface and an inner diameter surface defining a plurality of openings through the magnetic core material.

[0046] Each rotor may include a set of permanent magnets disposed within openings in an annular stack in a three-layer topology. Each of the three layers may contain at least three permanent magnets.

[0047] The three layers may include a first layer adjacent to the outer diameter surface, a second layer adjacent to the first layer, and a third layer adjacent to the inner diameter surface.

[0048] The set of permanent magnets can include (i) a plurality of low coercivity permanent magnets, and (ii) a plurality of high coercivity permanent magnets adjacent to the low coercivity permanent magnets. The plurality of low coercivity permanent magnets can be separated from the plurality of high coercivity permanent magnets by one or more radial webs of core material.

[0049] According to one aspect of the present disclosure, at least one of the three layers can include at least one of the plurality of low coercivity permanent magnets disposed on each side of one of the one or more radial webs of core material.

[0050] The low coercivity magnets can include, for example but not limited to, ferrite magnets, and / or other magnets containing less than about 10% rare earth elements by weight and / or less than about 1% heavy rare earth elements by weight. The high coercivity magnets can include, for example but not limited to, rare earth magnets such as Nd or Sm magnets.

[0051] Combining high coercivity (rare earth) magnets with parallel magnetization and low coercivity (ferrite) magnets with both parallel and radial magnetization in a parallel configuration can optimize the balance between sustainability and performance. Centering the ferrite magnets improves the saturation of structural members (e.g., the stack of laminations of an annularly stacked rotor lamination stack), minimizes cross demagnetization, increases rotor robustness, and improves high-speed operation while enabling the fabrication of curved magnets.

[0052] Distributing the rare earth magnets on each side of the ferrite magnets, towards the rotor surface, maximizes torque and provides robustness against demagnetization. Strategically placing three flux barriers within the rotor enhances torque performance while ensuring a smooth passage of the magnetic field.

[0053] Additionally, the ferrite permanent magnets reduce or eliminate the thin magnetic bridges of the annularly stacked rotor lamination stack in the web regions of the annularly stacked rotor lamination stack to improve the operating efficiency and performance of the motor, for example by reducing unwanted leakage flux / magnetic short circuits, while providing useful mechanical support.

[0054] The present invention provides the following technical solutions:

[0055] 1. A rotor for a rotating electric machine, the rotor comprising:

[0056] An annularly stacked rotor lamination stack (“rotorlams”) constructed of core material, the rotor lamination stack having an inner axial surface that collectively defines a first plurality of openings through the core material, a second plurality of openings through the core material, and a third plurality of openings through the core material;

[0057] A first plurality of permanent magnets, each respective one being disposed within a corresponding one of the first plurality of openings, wherein the first plurality of permanent magnets includes high coercivity magnets;

[0058] A second plurality of permanent magnets, each respective one being disposed within a corresponding one of the second plurality of openings, wherein the second plurality of permanent magnets includes low coercivity magnets; and

[0059] A third plurality of permanent magnets, each respective one being disposed within a corresponding one of the third plurality of openings, wherein the third plurality of permanent magnets includes additional high coercivity magnets.

[0060] 2. The rotor according to embodiment 1, wherein the first plurality of permanent magnets are arranged in a first stacked configuration, and each of the first plurality of permanent magnets has parallel magnetization.

[0061] 3. The rotor according to embodiment 2, wherein the third plurality of permanent magnets are arranged in a third stacked configuration, and each of the third plurality of permanent magnets has parallel magnetization.

[0062] 4. The rotor according to embodiment 3, wherein each of the first plurality of permanent magnets and each of the third plurality of permanent magnets has a rectangular configuration.

[0063] 5. The rotor according to embodiment 4, wherein the first plurality of permanent magnets and the third plurality of permanent magnets include rare earth magnets, and wherein the second plurality of permanent magnets includes ferrite magnets.

[0064] 6. The rotor according to embodiment 5, wherein the height of at least one of the ferrite magnets is greater than the height of at least one of the rare earth magnets.

[0065] 7. The rotor according to embodiment 1, wherein the second plurality of permanent magnets are arranged in a second stacked configuration, and each of the second plurality of permanent magnets has parallel magnetization.

[0066] 8. The rotor according to embodiment 1, wherein the second plurality of permanent magnets are arranged in a second stacked configuration including curved magnets having radial magnetization.

[0067] 9. The rotor according to embodiment 8, wherein at least one of the second plurality of openings includes a double-ridge profile.

[0068] 10. The rotor according to embodiment 1, wherein at least one of the second plurality of openings includes a polymer support layer between the permanent magnet corresponding to at least one of the second plurality of openings and at least one of the second plurality of openings.

[0069] 11. The rotor according to embodiment 1, wherein each of the second plurality of permanent magnets is bonded to the annular stacked rotor laminations.

[0070] 12. The rotor according to embodiment 1, wherein at least some of the first plurality of openings, the plurality of second openings, and the plurality of third openings define one or more cooling channels therethrough at positions adjacent to at least some of the first plurality of permanent magnets, the second plurality of permanent magnets, and the third plurality of permanent magnets.

[0071] 13. The rotor according to embodiment 1, further comprising a three - layer topology, comprising:

[0072] A first flux barrier, which is composed of the first magnet in the first plurality of permanent magnets, the first magnet in the second plurality of permanent magnets, and the first magnet in the third plurality of permanent magnets;

[0073] A second flux barrier, which is composed of the second magnet in the first plurality of permanent magnets, the second magnet in the second plurality of magnets, and the second magnet in the third plurality of magnets; and

[0074] A third flux barrier, which is composed of the third magnet in the first plurality of permanent magnets, the third magnet in the second plurality of permanent magnets, and the third magnet in the third plurality of permanent magnets.

[0075] 14. The rotor according to embodiment 13, further comprising a first radial web and a second radial web, wherein the first radial web is disposed between the first plurality of permanent magnets and the second plurality of permanent magnets, and wherein the second radial web is disposed between the second plurality of permanent magnets and the third plurality of permanent magnets.

[0076] 15. The rotor according to embodiment 14, wherein the first plurality of permanent magnets and the third plurality of permanent magnets comprise rare - earth magnets, and wherein the second plurality of permanent magnets comprises ferrite magnets.

[0077] 16. A rotating electrical machine, comprising:

[0078] A stator;

[0079] A rotor having an annular stack of laminated sheets ("rotor laminations") surrounded by the stator, the annular stack being made of a magnetic core material, the rotor laminations having an outer - diameter and an inner - diameter surface defining a plurality of openings therethrough; and

[0080] A set of permanent magnets disposed in the openings and arranged in a three - layer topology within the annular stack, each of the three layers containing at least three permanent magnets, the three layers comprising:

[0081] A first layer adjacent to the outer - diameter surface;

[0082] A second layer adjacent to the first layer; and

[0083] A third layer adjacent to the inner diameter surface, the set of permanent magnets including (i) a plurality of low coercivity permanent magnets, and (ii) a plurality of high coercivity permanent magnets adjacent to the plurality of low coercivity permanent magnets and separated therefrom by one or more radial webs of core material.

[0084] 17. The rotating electrical machine according to aspect 16, wherein at least one of the three layers includes at least one of the plurality of low coercivity magnets disposed on each side of one of the one or more radial webs of the core material.

[0085] 18. The rotating electrical machine according to aspect 16, wherein the low coercivity permanent magnets include ferrite magnets, and the high coercivity permanent magnets include rare earth permanent magnets, and wherein the second plurality of permanent magnets includes ferrite magnets.

[0086] 19. An electric vehicle, comprising:

[0087] An electric drive system, comprising:

[0088] A rotating electrical machine configured to be coupled to one or more wheels disposed on a drive shaft;

[0089] A battery pack electrically connected to the rotating electrical machine; and

[0090] A controller configured to control the rotating electrical machine, wherein the rotating

[0091] electrical machine includes:

[0092] A stator; and

[0093] A rotor having a plurality of laminated layers ("rotor laminations") surrounded by the stator, the plurality of rotor laminations being made of core material, the rotor laminations having an inner axial surface that collectively defines a first plurality of openings through the core material, a second plurality of openings through the core material, and a third plurality of openings through the core;

[0094] A first plurality of permanent magnets, each respective one being disposed within a corresponding one of the first plurality of openings, wherein the first plurality of permanent magnets includes high coercivity magnets;

[0095] A second plurality of permanent magnets, each respective one being disposed within a corresponding one of the second plurality of openings, wherein the second plurality of permanent magnets includes low coercivity magnets; and

[0096] A third plurality of permanent magnets, each respective one being disposed within a corresponding one of the third plurality of openings, wherein the third plurality of permanent magnets includes high coercivity magnets.

[0097] 20. The electric vehicle according to embodiment 19, wherein the first plurality of permanent magnets and the third plurality of permanent magnets comprise rare earth magnets, and wherein the second plurality of permanent magnets comprise ferrite magnets.

[0098] The foregoing summary is not representative of every embodiment or every aspect of the present disclosure. When taken in conjunction with the accompanying drawings and the appended claims, the foregoing features and advantages of the present disclosure, as well as other possible features and advantages, will become apparent from the following detailed description of the embodiments and best mode for carrying out the present disclosure. Additionally, the present disclosure expressly includes combinations and sub-combinations of the elements and features presented above and below. BRIEF DESCRIPTION OF THE DRAWINGS

[0099] Figure 1 is a schematic view of an exemplary motor vehicle having an electric drive system including a rotating electric machine according to the present disclosure, wherein the rotating electric machine has a rotor including low coercivity magnets and high coercivity magnets.

[0100] Figure 2A 、 Figure 2B and Figure 2C are schematic plan views of representative pole portions of a rotor according to the present disclosure, which rotor can be used as Figure 1 part of the electric machine shown.

[0101] Figure 3A 、 3B and 3C are schematic views according to the present disclosure of openings through Figure 2A the representative pole portions of the rotor shown.

[0102] Figures 3A-1 to 3A-4 is a schematic view according to the present disclosure of Figure 3A the laminated wall profile of the opening circled at location A shown.

[0103] Figure 4 is a schematic plan view showing a representative pole portion of a rotor that can be used as Figure 1 part of an electric machine, to which a plurality of permanent magnets are bonded according to the present disclosure.

[0104] Figure 5 is a schematic plan view of another representative pole portion of a rotor according to the present disclosure, which rotor is a Figure 1 usable part of the machine shown. DETAILED DESCRIPTION

[0105] The present disclosure may take many different forms of embodiments. Representative examples of the present disclosure are shown in the drawings and are described in detail herein as non-limiting examples of the disclosed principles. For this reason, elements and limitations described in the abstract, introduction, overview, and detailed description sections but not explicitly set forth in the claims should not be incorporated into the claims by implication, inference, or otherwise, either individually or collectively.

[0106] For the purposes of this description, unless explicitly stated otherwise, the use of the singular includes the plural and vice versa, the terms "and" and "or" shall be both conjunctive and disjunctive, "any" and "all" shall each mean "any and all", and the words "including", "containing", "comprising", "having", etc. shall mean "including but not limited to". In addition, approximating words such as "about", "almost", "substantially", "generally", "approximate" may be used herein in the sense of "at, close to, or almost at...", or "within 0 - 5% of...", or "within acceptable manufacturing tolerances", or a logical combination thereof.

[0107] Reference is made to the accompanying drawings, in which like reference numerals refer to like components. Figure 1 A motor vehicle 10 having an electric drive system 11 is schematically shown, and the electric drive system 11 includes a rotating electric machine (M E ) 12 in the form of an electric motor / generator unit. As described in detail below with reference to Figures 2A to 4 , the electric machine 12 includes a rotor 12R that is reinforced and assembled in accordance with the present disclosure. The described rotor 12R can be beneficial for various types of wheeled and / or tracked land vehicles, propeller-driven boats and aircraft, mobile work platforms, etc. Non-vehicle systems can similarly benefit from this teaching, such as including electrified powertrain architectures, power plants, mobile platforms, robots, lifting or conveying equipment, etc. Figure 1 The illustrated motor vehicle 10 thus merely illustrates one possible beneficial application.

[0108] The electric drive system 11 includes a rotating electric machine 12, the operation of which is regulated and controlled in real time by control signals (arrow CC O ) from an on-vehicle controller (C) 50. Those skilled in the art will understand that a motor controller, such as Figure 1 schematically represented controller 35, responds to input signals (arrow CC O ) by generating control signals (arrow CC I ) and transmitting them to one or more relevant subsystems within the electric drive system 11, such as driver pedal requests, the temperature and angular velocity of the electric machine 12, etc.

[0109] Instructions for controlling the electric machine 12 may be recorded in a memory (M) and be responded to by one or more processors (P) in response to input signals (arrow CCI ) and is executed in real time. Although omitted for simplicity, the controller 35 may include one or more electronic control modules, units, processors, and their associated hardware components, and will be equipped with sufficient memory (M), application-specific integrated circuits (ASICs), system-on-chips (SoCs), input / output circuits, high-speed clocks or oscillators, and other hardware and software in tangible and intangible variations as required to provide the desired functionality.

[0110] Figure 1 The illustrated electric machine 12 also includes a stator 12S. As understood in the art, the stator 12S may include slots wound or filled with conductive stator windings (not shown) such that when energized, the interaction between the stator 12S and the rotor 12R causes rotation of the rotor 12R. The rotor 12R is coupled via an output member 19 to one or more wheels 14 disposed on a drive shaft 22.

[0111] In the illustrated hybrid example of the motor vehicle 10, an internal combustion engine (E) 17 having a plurality of combustion cylinders 17C transmits engine torque (arrow T I ) to an input member 21 of a transmission (T) 20 (e.g., a multi-speed gearbox) via an input clutch C E ), while in other examples, such as when the motor vehicle 10 is configured as a battery electric vehicle, the engine 17 is omitted.

[0112] In the illustrated hybrid example, motor torque (arrow T M ) from the electric machine 12 is transmitted to the input member 21 either alone or in combination with engine torque (arrow T E ) supplied by the engine 17. In other embodiments, the electric machine 12 powers the transmission 20 alone, i.e., motor torque (arrow T M ) alone provides the input torque (arrow T I ), or the electric machine 12 may be directly coupled to one or more wheels 14 to act as a wheel motor (not shown). In the illustrated exemplary example, output torque (arrow T 0 ) is directed from an output member 121 of the transmission 20 via the drive shaft 22 to the wheels 14 to propel the motor vehicle 10.

[0113] The electric machine 12 is schematically shown in Figure 1 with the stator 12S coaxially disposed relative to the rotor 12R in a typical radial flux configuration, and the present teachings may also be extended to an axial flux configuration. In some examples, the electric machine 12 may be configured as a multi-phase / alternating current (AC) traction or propulsion motor. When so constructed, the electric drive system 11 may include a high voltage traction battery pack (B HV)15, such as a multi-cell rechargeable lithium-ion configuration or another suitable high-voltage / high-power battery chemistry. While the term "high voltage" is relative to a typical 12 - 15V auxiliary voltage level and thus may refer to any voltage level above it, an exemplary battery electric propulsion application of the type envisioned herein may require the battery pack 15 to have a voltage capability of 300 - 500V or higher.

[0114] Continuing to refer Figure 1 , the battery pack 15 may be electrically connected to the power inverter module (PIM) 16 via a high-voltage DC voltage bus (VDC), and the PIM 16 is in turn electrically connected to the stator 12S via a high-voltage AC voltage bus (VAC). Although the PIM 16 is omitted for simplicity of illustration, the PIM 16 is internally configured and externally controlled by the ON / OFF states of multiple dies of semiconductor switches, which are typically embodied as IGBTs or MOSFETs. Thus, the DC input voltage to the PIM 16 is inverted and controlled to ultimately deliver an AC output voltage and corresponding phase currents (Ia, Ib, Ic) through high-speed pulse-width modulation or other suitable switching operations of the PIM 16. In a regenerative event such as braking, the PIM 16 may operate in the reverse manner, i.e., by converting the AC input voltage into a DC output voltage suitable for recharging the constituent battery cells of the battery pack 15.

[0115] Other components may be connected to Figure 1 the illustrated electric drive system 11, such as but not limited to the illustrated DC - DC converter / auxiliary power module (APM) 25 and a lead-acid or other type of auxiliary battery (B AUX ) 26 operating at a lower auxiliary voltage (V AUX ). As described above, the auxiliary voltage level is typically 12 - 15V, so the APM 25 can operate through internal switching operations and signal filtering, as is well known in the art, to receive a relatively high DC voltage from the DC voltage bus (VDC) and output the auxiliary voltage (V AUX ) to the auxiliary battery 26. Thus, the motor 12 is just one of the multiple devices that require reliable and continuous electrical energy supply from the battery pack 15 during the continuous propulsion operation of the motor vehicle 10.

[0116] Now referring Figure 2A 、 Figure 2B and Figure 2C , there is provided Figure 1 a schematic plan view of a representative pole portion 12R of the rotor 12R shown in MAG , the pole portion 12R MAG comprises annularly stacked rotor laminations ("rotorlams") 120, one of which is from Figure 2A, 2B visible from the perspective of 2C. The rotor lamination 120 constructed of a core material (such as but not limited to silicon steel (FeSi) and / or cobalt steel (FeCo)) has inner axial surfaces 122, 123, and the inner axial surfaces 122, 123 together define a first plurality of openings 124 through the core material of the rotor lamination 120, a second plurality of openings 126 through the core material of the rotor lamination 120, and a third plurality of openings 128 through the core material of the rotor lamination 120.

[0117] A first plurality of permanent magnets 130 are disposed within the first plurality of openings 124 through the core material of the rotor lamination 120, and each respective one of the first plurality of permanent magnets 130 is disposed within a corresponding one of the first plurality of openings 124 through the core material of the rotor lamination 120. The first plurality of permanent magnets 130 include high coercivity magnets, such as but not limited to rare earth magnets, such as neodymium (Nd) magnets and / or samarium (Sm) magnets. Although the first plurality of magnets 130 include rare earth magnets, it should be understood that some of the first plurality of magnets 130 may not include rare earth magnets.

[0118] A second plurality of permanent magnets 132 are disposed within the second plurality of openings 126 through the core material of the rotor lamination 120, and each respective one of the second plurality of permanent magnets 132 is disposed within a corresponding one of the second plurality of openings 126 through the core material of the rotor lamination 120. The second plurality of permanent magnets include low coercivity magnets, such as but not limited to magnets including less than about 10% by weight of rare earth elements and / or less than about 1% by weight of heavy rare earth elements, such as FeN, ferrite, Alinco, and / or ceramic magnets. Although the second plurality of magnets 132 include magnets containing less than about 10% by weight of rare earth elements and / or less than about 1% by weight of heavy rare earth elements, it should be understood that some of the second plurality of magnets 132 may include more than about 10% by weight of rare earth elements and / or more than about 1% by weight of heavy rare earth elements.

[0119] In addition, although the illustrated example shows each of the second plurality of openings 125 as having a curved profile and the second plurality of permanent magnets 132 include curved magnets, it should be understood that the second plurality of openings 126 may alternatively have a flat profile and the second plurality of permanent magnets 132 may alternatively include rectangular or flat magnets with parallel magnetization.

[0120] A third plurality of permanent magnets 134 are provided with a third plurality of openings 128 through the core material of the rotor lamination 120, with each respective one of the third plurality of permanent magnets 134 being disposed within a corresponding one of the third plurality of openings 128. The third plurality of permanent magnets 134 includes high coercivity magnets, such as but not limited to rare earth magnets, such as Nd or Sm magnets. Although the third plurality of magnets 134 includes rare earth magnets, it should be understood that some of the third plurality of magnets 134 may not include rare earth magnets.

[0121] In addition, although each of the first plurality of permanent magnets 130, the second plurality of permanent magnets 132, and the third plurality of permanent magnets 134 is shown as having a one-piece construction, it should be understood that, based on the individual application, one or more of the first plurality of permanent magnets 130, the second plurality of permanent magnets 132, and the third plurality of permanent magnets 134 may alternatively have a segmented construction, where each permanent magnet includes two or more magnet portions bonded together using an epoxy or phenolic adhesive, such as but not limited to polyurethane, benzoxazine, bismaleimide, methacrylate, etc.

[0122] The first plurality of permanent magnets 130 are arranged in a first stacked configuration 140, with each of the first plurality of permanent magnets 130 having parallel magnetization, as indicated by the arrows 146 in Figure 2B and 2C .

[0123] The second plurality of permanent magnets 132 are arranged in a second stacked configuration 142.

[0124] According to another aspect of the present disclosure, the second plurality of permanent magnets 132 includes curved magnets having parallel magnetization as indicated by the arrows 148 in Figure 2B , or radial magnetization as indicated by the arrows 152 in Figure 2C .

[0125] The third plurality of permanent magnets 134 are arranged in a third stacked configuration 144, with each of the third plurality of permanent magnets 134 having parallel magnetization, as indicated by the arrows 150 in Figure 2B and 2C .

[0126] Now referring to Figure 3A , Figure 3B and Figure 3C , there is provided a schematic cross-sectional plan view ([[]] Figure 3B [[]]) of a representative one of the first plurality of openings 124 through the core material of the rotor lamination 120 shown in [[[]] Figure 1 [[]]], a schematic cross-sectional plan view ([[]] Figure 3A [[]]) of a representative one of the second plurality of openings 126 through the core material of the rotor lamination 120 shown in [[[]] Figure 1 [[]]], Figure 1 ), through Figure 3B ), through Figure 1 and Figure 3A), and passing through Figure 1 A schematic cross-sectional plan view of a representative one of a third plurality of openings 128 in the core material of the rotor lamination 120 shown in Figure 3C ).

[0127] As Figure 3A Further shown, each bent magnet 132 includes a first bent surface 132A and a second bent surface 132B. The inner axial surfaces 122, 123 of each of the second plurality of openings 126 have curved profiles 122 CP , 123 CP ( Figure 3A-1 ), and each bent magnet 132 is disposed within a second plurality of openings 126 passing through the core material of the annular rotor lamination 120.

[0128] According to another aspect of the present disclosure, the inner axial surface 123 of at least one of the second plurality of openings 126 includes a single raised profile 123 SH , as Figure 3A-2 shown, or a double-raised profile 123 DH , as Figure 3A-3 shown. Although the illustrated examples show that the inner axial surface 123 of at least one of the second plurality of openings 126 has a single-raised profile or a double-raised profile, it should be understood that based on individual applications, the profile of the inner axial surface 123 may include more than two raised portions.

[0129] According to another aspect of the present disclosure, as Figure 3A-4 shown, at least one of the second plurality of openings 126 includes a polymer support layer 160 between the bent magnet 132 corresponding to at least one of the second plurality of openings 126 and at least one of the second plurality of openings 126.

[0130] The polymer support layer 160 may include, but is not limited to, epoxy resin, phenolic binder, polyurethane, benzoxazine, bismaleimide, methacrylate, etc. The polymer support layer 160 may also include mineral or fiber fillers to increase stiffness, strength, and / or reduce thermal expansion.

[0131] According to another aspect of the present disclosure, as Figure 4 shown, each of the second plurality of permanent magnets 132 is bonded to the annularly stacked rotor lamination 120 via an adhesive 162, and the adhesive 162 is, for example but not limited to, epoxy resin, phenolic binder, polyurethane, benzoxazine, bismaleimide, methacrylate, etc. According to one aspect of the present disclosure, the adhesive 162 may include mineral and / or fiber fillers to increase stiffness and / or strength, and / or reduce the coefficient of thermal expansion.

[0132] Before bonding each of the plurality of second magnets 132 to the annularly stacked rotor laminations 120 via an adhesive 162, a primer, such as but not limited to epoxy resin, phenolic resin, and / or polyurethane, or a surface treatment, such as but not limited to plasma treatment, silane treatment, and / or chemical conversion coating, may be applied to the surface of each of the plurality of second magnets 132.

[0133] As Figure 3B and 3C shown, with continued reference to FIG. 2, each of the first plurality of permanent magnets 130 disposed within the first plurality of openings 124 of the core material passing through the rotor laminations 120, and each of the third plurality of permanent magnets 134 disposed within the third plurality of openings 128 of the core material passing through the rotor laminations 120, has a rectangular configuration.

[0134] According to one aspect of the present disclosure, the first plurality of permanent magnets 130 and the third plurality of permanent magnets 134 comprise rare earth magnets, and the second plurality of permanent magnets 132 comprise ferrite magnets.

[0135] The height H of at least one of the second plurality of permanent magnets 132 F is greater than the height H of at least one of the first plurality of permanent magnets 130 and / or at least one of the second plurality of permanent magnets 132 R .

[0136] As Figures 2A to 3C and Figure 4 shown, at least some of the first plurality of openings 124, the plurality of second openings 126, and the plurality of third openings 128 define one or more cooling channels C therethrough at least in proximity to at least some of the first plurality of permanent magnets 130, the second plurality of permanent magnets 132, and the third plurality of permanent magnets 134 C .

[0137] Returning to FIG. 2, the rotor laminations 120 include a three - layer topology having a first flux barrier 170, a second flux barrier 172, a third flux barrier 174, a first radial web 176, and a second radial web 178.

[0138] The first flux barrier 170 is composed of the first magnet 130' among the first plurality of permanent magnets, the first magnet 132' among the second plurality of permanent magnets 132, and the first magnet 134' among the third plurality of permanent magnets 134. The second flux barrier 172 is composed of the second magnet 130'' among the first plurality of permanent magnets 130, the second magnet 132'' among the second plurality of magnets 132, and the second magnet 134'' among the third plurality of magnets 134. The third flux barrier 174 is composed of the third magnet 130''' among the first plurality of permanent magnets 130, the third magnet 132''' among the second plurality of permanent magnets 132, and the third magnet 134''' among the third plurality of permanent magnets 134.

[0139] The first radial web 176 is disposed between the first plurality of permanent magnets 130 and the second plurality of permanent magnets 132. The second radial web 178 is disposed between the second plurality of permanent magnets 132 and the third plurality of permanent magnets 134.

[0140] The first plurality of permanent magnets 130 and the third plurality of permanent magnets 134 include rare earth magnets, such as Nd magnets, and the second plurality of permanent magnets 132 include magnets containing less than about 10% by weight of rare earth elements and / or less than about 1% by weight of heavy rare earth elements, such as ferrite magnets.

[0141] Return to reference Figure 1 A rotating electrical machine is disclosed, which includes a stator 12S and a rotor 12R. The rotor 12R has a plurality of laminated sheets ("rotor laminated sheets") 120 surrounded by the stator 12S. Each of the plurality of rotor laminated sheets 120 constructed of a magnetic core material includes inner axial surfaces 122, 123, and the inner axial surfaces 122, 123 together define a first plurality of openings 124 through the magnetic core material of the rotor laminated sheet 120, a second plurality of openings 126 through the magnetic core material of the rotor laminated sheet 120, and a third plurality of openings 128 through the magnetic core material of the rotor laminated sheet 120.

[0142] The first plurality of permanent magnets 130, with each respective one disposed within a corresponding one of the first plurality of openings 124, wherein the first plurality of permanent magnets 130 include high coercivity magnets.

[0143] The second plurality of permanent magnets 132, with each respective one disposed within a corresponding one of the second plurality of openings 126, wherein the second plurality of permanent magnets 132 include low coercivity magnets.

[0144] The third plurality of permanent magnets 134, with each respective one disposed within a corresponding one of the third plurality of openings 128, wherein the third plurality of permanent magnets 134 include high coercivity magnets.

[0145] The first plurality of permanent magnets 130 are arranged in a first stacked configuration 140, wherein each of the first plurality of permanent magnets 130 has parallel magnetization.

[0146] The second plurality of permanent magnets 132 are arranged in a second stacked configuration 142, wherein each of the second plurality of permanent magnets 132 has parallel magnetization and radial magnetization.

[0147] The third plurality of permanent magnets 134 are arranged in a third stacked configuration 144, wherein each of the third plurality of permanent magnets 134 has parallel magnetization.

[0148] The first plurality of permanent magnets 130 and the third plurality of permanent magnets 134 include rare earth magnets, such as Nd magnets, while the second plurality of permanent magnets 132 include magnets containing less than about 10% by weight of rare earth elements and / or less than about 1% by weight of heavy rare earth elements, such as ferrite magnets.

[0149] Return reference Figure 1 , also disclosed is a motor vehicle 10 including an electric drive system 11 (“electric vehicle”) having a rotating electric machine (M E ) 12, wherein the rotating electric machine 12 has a rotor 12R including low coercivity magnets and high coercivity magnets. The electric vehicles 10, 11 having the rotating electric machine 12 are configured to be coupled to one or more wheels 14 disposed on a drive shaft 22. A battery pack 15 is electrically connected to the rotating electric machine 12, and a controller 35 is configured to control the rotating electric machine 12.

[0150] The rotating electric machine 12 includes a stator 12S and a rotor 12R, and the rotor 12R has a plurality of laminated layers (“rotor laminated layers”) 120 surrounded by the stator 12S. The plurality of rotor laminated layers 120 constructed of a core material include inner axial surfaces 122, 123 that together define a first plurality of openings through the core material of the rotor laminated layers 120, a second plurality of openings through the core material of the rotor laminated layers 120, and a third plurality of openings through the core of the rotor laminated layers 120.

[0151] The first plurality of permanent magnets 130, each respective one being disposed in a corresponding one of the first plurality of openings 124. The first plurality of permanent magnets 130 include high coercivity magnets.

[0152] Each respective one of the second plurality of permanent magnets 132 is disposed in a corresponding one of the second plurality of openings 126. The second plurality of permanent magnets 132 include low coercivity magnets.

[0153] The third plurality of permanent magnets 134, each respective one being disposed in a corresponding one of the third plurality of openings 128. The third plurality of permanent magnets 134 include high coercivity magnets.

[0154] The first plurality of permanent magnets 130 and the third plurality of permanent magnets 134 include rare earth magnets, such as Nd magnets, while the second plurality of permanent magnets 132 include magnets containing less than about 10% rare earth elements by weight and / or about 1% heavy rare earth elements by weight, such as ferrite magnets.

[0155] Now refer to Figure 5 , there is provided Figure 1 Another representative pole portion 12R of the rotor 12R shown MAG in a schematic plan view, the pole portion 12R MAG includes annularly stacked rotor laminations ("rotor lams") 220, one of which is visible from the Figure 5 perspective. The rotor laminations 220 constructed of a core material (such as but not limited to silicon steel (FeSi) and / or cobalt steel (FeCo)) have inner axial surfaces 222, 223 that jointly define a plurality of openings 224 through the core material of the rotor laminations 220.

[0156] The rotor laminations 220 have an outer diameter surface 23 - O and an inner diameter surface 23 - I that define a plurality of openings 224 through the core material of the rotor laminations 220.

[0157] Each rotor lamination 220 includes a set of permanent magnets 230, 232, 234 that are disposed in the openings 224 within the annularly stacked rotor laminations 220 in a three - layer topology. Each of the three layers 270, 272, 274 contains at least three permanent magnets 230, 232, 234.

[0158] The three layers can include a first layer 274 adjacent to the outer diameter surface 23 - O, a second layer 272 adjacent to the first layer 274, and a third layer 270 adjacent to the inner diameter surface 23 - I.

[0159] The set of permanent magnets 230, 232, 234 includes (i) a plurality of low coercivity permanent magnets 232, and (ii) a plurality of high coercivity permanent magnets 230, 234 adjacent to the low coercivity permanent magnets 232. The plurality of low coercivity permanent magnets 232 are separated from the plurality of high coercivity permanent magnets 230, 234 by one or more radial webs 276 of the core material of the rotor laminations 220.

[0160] According to one aspect of the present disclosure, at least one of the three layers 270, 272, 274 includes at least one of the plurality of low coercivity permanent magnets 232 disposed on each side of one of the one or more radial webs 276 of the core material of the rotor laminations 220.

[0161] The low coercivity magnet 232 may include, for example but not limited to, a ferrite magnet, and / or other magnets including less than about 10% rare earth elements by weight and / or less than about 1% heavy rare earth elements by weight. The high coercivity magnets 230, 234 may include, for example but not limited to, rare earth magnets such as Nd or Sm magnets.

[0162] As understood in the art, such a pole portion 12R MAG repeats around the entire circumference of the annular rotor lamination 120, and the number of such pole portions 12R in a given configuration of the rotor 12R MAG is thus equal to the number of poles of the rotor 12R. The exemplary pole portion 12R MAG is depicted as having non-limiting representative dimensions and internal construction, in this case Figure 1 one of six pole portions 12R in a 6-pole configuration of the rotor 12R MAG each, and each pole portion 12R MAG defines nine rotor openings 124, 126, 128. In other words, in various embodiments, the rotor 12R may have fewer or more pole portions 12R MAG , regardless of the number, shape, and orientation of the depicted rotor openings 124, 126, 128.

[0163] Each fully formed rotor lamination 120 defines a closed annular space or ring having an outer diameter surface 23-O and an inner diameter surface 23-I, as understood in the art, and thus a given pole portion 12R MAG extends radially between its respective outer diameter surface 23-O and inner diameter surface 23-I. When fully assembled, the rotor 12R and its constituent axially extending annular stack of rotor laminations 120 form a cylindrical central pivot. A rotor shaft (not shown) may be splined or otherwise engaged to the inner diameter surface 23-I of the annular stack of rotor laminations 120 and coupled to a load 24, such as Figure 1 the output member 19, the transmission 20, and / or the shaft 22 as shown.

[0164] Thus, the foregoing disclosure can be implemented by the annular stack of rotor laminations 120 having high coercivity permanent magnets and low coercivity permanent magnets configured as described herein Figure 1 for the rotor 12R shown in the non-limiting applications.

[0165] The detailed description and the drawings or figures support and describe the present teachings, but the scope of the present teachings is defined only by the claims. Although some best modes and other embodiments for carrying out the present teachings have been described in detail, there are various alternative designs and embodiments for practicing the present teachings as defined in the appended claims. In addition, the present disclosure expressly includes combinations and sub-combinations of the elements and features presented above and below.

Claims

1. A rotor for a rotating electric machine, the rotor comprising: annularly stacked rotor lamination layers ("rotor laminations") constructed of a core material, the rotor lamination layers having inner axial surfaces that collectively define a first plurality of openings through the core material, a second plurality of openings through the core material, and a third plurality of openings through the core material; a first plurality of permanent magnets, each respective one disposed within a corresponding one of the first plurality of openings, wherein the first plurality of permanent magnets comprises high coercivity magnets; a second plurality of permanent magnets, each respective one disposed within a corresponding one of the second plurality of openings, wherein the second plurality of permanent magnets comprises low-coercivity magnets; and A third plurality of permanent magnets, each respective one of which is disposed within a corresponding one of the third plurality of openings, wherein the third plurality of permanent magnets includes additional high-coercivity magnets. 2 . The rotor of claim 1 , wherein the first plurality of permanent magnets are arranged in a first stacked configuration, each of the first plurality of permanent magnets having a parallel magnetization. 3 . The rotor of claim 2 , wherein the third plurality of permanent magnets are arranged in a third stacked configuration, each of the third plurality of permanent magnets having a parallel magnetization. 4 . The rotor of claim 3 , wherein the first plurality of permanent magnets and the third plurality of permanent magnets comprise rare earth magnets, and wherein the second plurality of permanent magnets comprises ferrite magnets. 5 . The rotor of claim 1 , wherein the second plurality of permanent magnets are arranged in a second stacked configuration, each of the second plurality of permanent magnets having a parallel magnetization.

6. The rotor of claim 1, wherein the second plurality of permanent magnets are arranged in a second stacked configuration comprising curved magnets having radial magnetization. 7 . The rotor of claim 1 , wherein at least one of the second plurality of openings comprises a polymer support layer between a permanent magnet corresponding to at least one of the second plurality of openings and the at least one of the second plurality of openings.

8. The rotor of claim 1, wherein each of the second plurality of permanent magnets is bonded to the annularly stacked rotor lamination layers.

9. The rotor of claim 1 , wherein at least some of the first plurality of openings, the second plurality of openings, and the third plurality of openings define one or more cooling passages therethrough at locations adjacent to at least some of the first plurality of permanent magnets, the second plurality of permanent magnets, and the third plurality of permanent magnets.

10. The rotor according to claim 1, further comprising a three-layer topology, comprising: a first flux barrier comprised of a first magnet in the first plurality of permanent magnets, a first magnet in the second plurality of permanent magnets, and a first magnet in the third plurality of permanent magnets; a second flux barrier comprised of a second magnet from the first plurality of permanent magnets, a second magnet from the second plurality of magnets, and a second magnet from the third plurality of magnets; and A third flux barrier is comprised of a third magnet from the first plurality of permanent magnets, a third magnet from the second plurality of permanent magnets, and a third magnet from the third plurality of permanent magnets.

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