Patent Publication Number: US-2023143600-A1

Title: Aircraft electric motor

Description:
STATEMENT OF FEDERAL SUPPORT 
     This invention was made with government support under Contract No. DE-AR0001351 awarded by the U.S. Department of Energy. The government has certain rights in the invention. 
    
    
     BACKGROUND 
     The present disclosure relates to electric motors, and more particularly, to electric motor assemblies with high efficiency and power density with a light weight for aircraft applications. 
     Traditional electric motors may include a stator and a rotor, with electrical motor windings in the stator that, when energized, drive rotation of the rotor about a central axis. Heat is generated in the motor windings, which are located in slots in the stator. The windings are separated from the exterior of the motor by layers of insulation and laminated steel, which makes up the stator. These contributors to internal thermal resistance limit the allowable heat generation and thus the allowable electrical current in the windings. The energy density of an electric motor is typically limited by heat dissipation from the motor windings of the stator. The requirement to be met is a maximum hot spot temperature in the motor windings that is not to be exceeded. Conventional motor thermal management includes natural convection from large fins on the outside of a motor jacket, or liquid cooling in the motor jacket. Both of these solutions undesirably add volume and/or weight to the motor, due to the addition of, at least, the jacket. 
     BRIEF DESCRIPTION 
     According to some embodiments of the present disclosure, aircraft electric motors are provided. The aircraft electric motors include a motor unit having a rotor and a stator, wherein the stator includes a plurality of windings and cooling channels arranged to provide cooling to the plurality of windings, a drive unit configured to drive operation of the motor unit, and a cooling system. The cooling system includes an oscillating heat pipe containing a first working fluid, wherein the oscillating heat pipe is arranged to pick up heat from at least one winding, the oscillating heat pipe having an evaporator section arranged in thermal contact with the at least one winding and a condenser section arranged away from the evaporator section and a heat pickup portion arranged to receive a second working fluid to remove heat from the condenser section of the oscillating heat pipe. 
     In addition to one or more of the features described herein, or as an alternative, further embodiments of the aircraft electric motors may include a cold plate, wherein the heat pickup portion is part of the cold plate. 
     In addition to one or more of the features described herein, or as an alternative, further embodiments of the aircraft electric motors may include that the cold plate comprises one or more heat dispersion elements arranged to thermally interact with the second working fluid. 
     In addition to one or more of the features described herein, or as an alternative, further embodiments of the aircraft electric motors may include that the heat dispersion elements comprise at least one of fins and pedestals. 
     In addition to one or more of the features described herein, or as an alternative, further embodiments of the aircraft electric motors may include that the heat pick up portion comprises at least one cooling channel formed within the cold plate and configured to receive the second working fluid. 
     In addition to one or more of the features described herein, or as an alternative, further embodiments of the aircraft electric motors may include a pump configured to pump the second working fluid through the at least one cooling channel formed within the cold plate. 
     In addition to one or more of the features described herein, or as an alternative, further embodiments of the aircraft electric motors may include a heat exchanger fluidly coupled to the at least one cooling channel formed within the cold plate, the heat exchanger configured to receive the second working fluid to remove heat therefrom. 
     In addition to one or more of the features described herein, or as an alternative, further embodiments of the aircraft electric motors may include that the cold plate is configured to structurally support at least a portion of the stator. 
     In addition to one or more of the features described herein, or as an alternative, further embodiments of the aircraft electric motors may include that the oscillating heat pipe is integrally formed with the cold plate as a unitary structure. 
     In addition to one or more of the features described herein, or as an alternative, further embodiments of the aircraft electric motors may include that the oscillating heat pipe is embedded within the at least one winding. 
     In addition to one or more of the features described herein, or as an alternative, further embodiments of the aircraft electric motors may include that the oscillating heat pipe is arranged as an in-slot structure arranged adjacent to and in thermal contact with the at least one winding. 
     In addition to one or more of the features described herein, or as an alternative, further embodiments of the aircraft electric motors may include a motor housing arranged about the stator, wherein the heat pickup portion is part of the motor housing. 
     In addition to one or more of the features described herein, or as an alternative, further embodiments of the aircraft electric motors may include that the evaporator section of the oscillating heat pipe is arranged within the stator and the condenser section is arranged within the motor housing. 
     In addition to one or more of the features described herein, or as an alternative, further embodiments of the aircraft electric motors may include that the windings are arranged in a U-shape configuration. 
     In addition to one or more of the features described herein, or as an alternative, further embodiments of the aircraft electric motors may include that the motor unit comprises rotor having U-shaped magnets arranged about the windings of the stator. 
     In addition to one or more of the features described herein, or as an alternative, further embodiments of the aircraft electric motors may include that the cooling system further includes a header and a heat exchanger configured to supply the second working fluid to the heat pickup portion. 
     In addition to one or more of the features described herein, or as an alternative, further embodiments of the aircraft electric motors may include that the rotor and stator are arranged in an annular configuration. 
     In addition to one or more of the features described herein, or as an alternative, further embodiments of the aircraft electric motors may include that the first working fluid is a saturated refrigerant. 
     In addition to one or more of the features described herein, or as an alternative, further embodiments of the aircraft electric motors may include that the first working fluid is a dielectric refrigerant. 
     In addition to one or more of the features described herein, or as an alternative, further embodiments of the aircraft electric motors may include that the dielectric refrigerant is a hydrofluorocarbon (HFC), a hydrofluro-olefin (HFO), or a hydrofluoroether (HFE). 
     According to some embodiments, aircraft electric motors are provided. The aircraft electric motors include a motor unit having a rotor and a stator, wherein the stator includes a plurality of windings and cooling channels arranged to provide cooling to the plurality of windings, a means for driving operation of the motor unit, and a cooling system. The cooling system includes an oscillating heat pipe containing a first working fluid, wherein the oscillating heat pipe is arranged to pick up heat from at least one winding, the oscillating heat pipe having an evaporator section arranged in thermal contact with the at least one winding and a condenser section arranged away from the evaporator section and a means for heat pickup arranged to receive a second working fluid to remove heat from the condenser section of the oscillating heat pipe. 
     In addition to one or more of the features described herein, or as an alternative, further embodiments of the aircraft electric motors may include that the means for driving operation of the motor unit comprises at least one power module system, and the means for heat pickup comprises a cold plate. 
     The foregoing features and elements may be executed or utilized in various combinations without exclusivity, unless expressly indicated otherwise. These features and elements as well as the operation thereof will become more apparent in light of the following description and the accompanying drawings. It should be understood, however, that the following description and drawings are intended to be illustrative and explanatory in nature and non-limiting. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various features will become apparent to those skilled in the art from the following detailed description of the disclosed non-limiting embodiments. The drawings that accompany the detailed description can be briefly described as follows: 
         FIG.  1 A  is a partial view of an embodiment of electric motor; 
         FIG.  1 B  is a cross-sectional view of an embodiment of a stator core of the electric motor of  FIG.  1 A ; 
         FIG.  2 A  is a schematic illustration of an aircraft electric motor in accordance with an embodiment of the present disclosure; 
         FIG.  2 B  is a side elevation view of the aircraft electric motor of  FIG.  2 A ; 
         FIG.  2 C  is a partial cut-away illustration of the aircraft electric motor of  FIG.  2 A ; 
         FIG.  2 D  is a separated-component illustration of the aircraft electric motor of  FIG.  2 A ; 
         FIG.  3 A  is a schematic illustration of a rotor and stator of an aircraft electric motor in accordance with an embodiment of the present disclosure; 
         FIG.  3 B  is a schematic illustration of the rotor and stator of  FIG.  3 A  as arranged within a rotor sleeve in accordance with an embodiment of the present disclosure; 
         FIG.  4    is a schematic illustration of a portion of an aircraft electric motor system in accordance with an embodiment of the present disclosure; 
         FIG.  5    is a schematic illustration of a portion of an aircraft electric motor system in accordance with an embodiment of the present disclosure; 
         FIG.  6 A  is a schematic illustration of a portion of an aircraft electric motor system in accordance with an embodiment of the present disclosure; 
         FIG.  6 B  is an alternative view of the portion of an aircraft electric motor system of  FIG.  6 A ; and 
         FIG.  7    is a schematic view of a power system of an aircraft that may employ embodiments of the present disclosure. 
     
    
    
     The foregoing features and elements may be combined in various combinations without exclusivity, unless expressly indicated otherwise. These features and elements as well as the operation thereof will become more apparent in light of the following description and the accompanying drawings. It should be understood, however, that the following description and drawings are intended to be illustrative and explanatory in nature and non-limiting. 
     DETAILED DESCRIPTION 
     Referring to  FIGS.  1 A- 1 B , schematic illustrations of an electric motor  100  that may incorporate embodiments of the present disclosure are shown.  FIG.  1 A  illustrates a cross-sectional view of the electric motor  100  and  FIG.  1 B  illustrates a cross-sectional view of a stator core of the electric motor  100 . The electric motor  100  includes a rotor  102  configured to rotate about a rotation axis  104 . A stator  106  is located radially outboard of the rotor  102  relative to the rotation axis  104 , with a radial air gap  108  located between the rotor  102  and the stator  106 . As illustrated, the rotor  102  may be mounted on a shaft  110  which may impart rotational movement to the rotor  102  or may be driven by rotation of the rotor  102 , as will be appreciated by those of skill in the art. The rotor  102  and the shaft  110  may be fixed together such that the rotor  102  and the shaft  110  rotate about the rotation axis  104  together as one piece. 
     The stator  106  includes a stator core  112  in which a plurality of electrically conductive stator windings  114  are disposed. In some embodiments, such as shown in  FIG.  1 A , the stator core  112  is formed from a plurality of axially stacked laminations  116 , which are stacked along the rotation axis  104 . In some embodiments, the laminations  116  are formed from a steel material, but one skilled in the art will readily appreciate that other materials may be utilized. The stator windings  114 , as shown, include core segments  118  extending through the stator core  112  and end turn segments  120  extending from each axial stator end  122  of the stator core  112  and connecting circumferentially adjacent core segments  118 . When the stator windings  114  are energized via an electrical current therethrough, the resulting field drives rotation of the rotor  102  about the rotation axis  104 . Although  FIG.  1 A  illustrates the stator core  112  arranged radially inward from the stator windings  114 , it will be appreciated that other configurations are possible without departing from the scope of the present disclosure. For example, in some embodiments, the stator structure may be arranged radially inward from a rotating rotor structure. 
       FIG.  1 B  is an axial cross-sectional view of the stator core  112 . Each lamination  116  of the stator core  112  includes a radially outer rim  124  with a plurality of stator teeth  126  extending radially inwardly from the outer rim  124  toward the rotation axis  104 . Each of the stator teeth  126  terminate at a tooth tip  128 , which, together with a rotor outer surface  130  (shown in  FIG.  1 A ) of the rotor  102 , may define the radial air gap  108 . Circumferentially adjacent stator teeth  126  define an axially-extending tooth gap  132  therebetween. Further, in some embodiments, a plurality of stator fins  134  extend radially outwardly from the outer rim  124 . 
     Electric motors, as shown in  FIGS.  1 A- 1 B  may require cooling due to high density configurations, various operational parameters, or for other reasons. For example, high-power-density aviation-class electric motors and drives may require advanced cooling technologies to ensure proper operation of the motors/drives. These machines are generally thermally limited at high power ratings and their performance can be improved by mitigating thermal limitations. To maintain desired temperatures, a thermal management system (TMS) is integrated into the system, which provides cooling to components of the system. 
     Onboard an aircraft, power requirements, and thus thermal management system (TMS) loads, are substantially higher during takeoff. Sizing of the TMS for takeoff conditions (i.e., maximum loads) results in a TMS having a high weight to accommodate such loads. This results in greater weight and lower power density during cruise conditions which do not generate such loads, and thus does not require a high cooling capacity TMS. Balancing weight constraints and thermal load capacities is important for such aviation applications. 
     In view of such considerations, improved aviation electric motors are provided herein. The aviation electric motors or aircraft electric motors, described herein, incorporate lightweight materials and compact design to reduce weight, improve thermal efficiencies, improve power efficiencies, and improve power density. 
     Turning now to  FIGS.  2 A- 2 D , schematic illustrations of an aircraft electric motor  200  in accordance with an embodiment of the present disclosure are shown.  FIG.  2 A  is an isometric illustration of the aircraft electric motor  200 ,  FIG.  2 B  is a side elevation view of the aircraft electric motor  200 ,  FIG.  2 C  is a partial cut-away view illustrating internal components of the aircraft electric motor  200 , and  FIG.  2 D  is a schematic illustration of components of the aircraft electric motor  200  as separated from each other. The aircraft electric motor  200  includes a motor housing  202 , a cooling system  204 , a first power module system  206 , and a second power module system  208 . 
     The motor housing  202  houses a stator  210  and a rotor  212 , with the rotor  212  configured to be rotatable about the stator  210 . In this illustrative embodiment, the rotor  212  includes a U-shaped magnet  214  arranged within a similarly shaped U-shaped rotor sleeve  216 . The rotor sleeve  216  is operably connected to a hub  218 . The hub  218  is fixedly attached to a first shaft  220 . The first shaft  220  is operably connected to a second shaft  222 . In some configurations, the first shaft  220  may be a high speed shaft and may be referred to as an input shaft. In such configurations, the second shaft  222  may be a low speed shaft and may be referred to as an output shaft. The connection between the first shaft  220  and the second shaft  222  may be by a gear assembly  224 , as described herein. 
     The cooling system  204  is configured to provide cooling to the components of the aircraft electric motor  200 . The cooling system  204 , as shown in  FIG.  2 D , includes a heat exchanger  226  and a header  228 . The heat exchanger  226  and the header  228  may form a closed-loop cooling system that may provide air-cooling to a working fluid at the heat exchanger  226 . The header  228  may be, in some configurations, a two-phase di-electric cooling header. A cooled working fluid may be pumped from the heat exchanger  226  into the header  228  using a pump  229  and distributed into embedded cooling channels  230  that are arranged within the stator  210 . As the aircraft electric motor  200  is operated, heat is generated and picked up by the working fluid within the embedded cooling channels  230 . This heated working fluid is then passed through the header  228  back to the heat exchanger  226  to be cooled, such as by air cooling. Although described as air-cooling, other cooling processes may be employed without departing from the scope of the present disclosure. 
     As shown, the heat exchanger  226  of the cooling system  204  may be a circular structure that is arranged about the motor housing  202 . This configuration and arrangement allows for improved compactness of the system, which may be advantageous for aircraft applications. The rotor sleeve  216  with the magnets  214 , the stator  210 , and the gear assembly  224  fit together (although moveable relative to each other) within the motor housing  202 , providing for a compact (low volume/size) design. 
     As noted above, the rotor sleeve  216  may be operably coupled to a first shaft  220  by the hub  218 . The first shaft  220  may be operably coupled to a first gear element  232  and the second shaft  222  may be operably coupled to a second gear element  234 . The first and second gear elements  232 ,  234  may form the gear assembly  224 . The first and second gear elements  232 ,  234  are arranged to transfer rotational movement from the first shaft  220 , which is driven in rotation by the hub  218  and the rotor sleeve  216  of the rotor  212 , to the second shaft  222 . In some embodiments, the first shaft  220  may be operably connected to a sun gear as the first gear element  232  that engages with a plurality of planetary gears and drives rotation of the second gear element  234  which may be operably connected to the second shaft  222 . In some embodiments, the second shaft  222  may be connected to a fan or other component to be rotated by the aircraft electric motor  200 . 
     The aircraft electric motor  200  includes the first power module system  206  and the second power module system  208 , which may form, in part, a drive unit of the aircraft electric motor  200 . The first and second power module systems  206 ,  208  can include capacitors and other electronics, including, but not limited to, printed circuit boards (PCBs) that may enable control and operation of the aircraft electric motor  200 . Again, the profile of the aircraft electric motor  200  of the present disclosure presents a low profile or compact arrangement that reduces the volume of the entire power system, which in turn can provide for improved weight reductions. In some embodiments, the first and second power module systems  206 ,  208  may be electrically connected to the stator  210  to cause an electric current therein. As the electric current will induce an electromagnetic field which will cause the rotor  212  to rotate. 
     Referring now to  FIGS.  3 A- 3 B , schematic illustrations of a portion of an aircraft electric motor  300  in accordance with an embodiment of the present disclosure is shown.  FIGS.  3 A- 3 B  illustrate a portion of a rotor  302  and a stator  304  of the aircraft electric motor  300 .  FIG.  3 A  illustrates the rotor  302  and the stator  304  and  FIG.  3 B  illustrates these components arranged within a rotor sleeve  306 . 
     The rotor  302  is formed of a plurality of U-shaped magnets  308 . In some configurations, the plurality of magnets  308  can be arranged with alternating polarity in a circular or annular structure. Arranged within the “U” of the U-shaped magnets  308  is the stator  304 . The stator  304  is formed of a plurality of windings  310 . In this configuration, the windings  310  are arranged with a header  312 . The header  312  may be part of a cooling system, such as that shown and described above. The header  312  can be configured to cycle a working fluid through cooling channels  314  for cooling of the windings  310 , as shown in  FIG.  3 B . As shown in  FIG.  3 B , the cooling channels  314  may include a flow restrictor  315  arranged at an inlet side (or an outlet side) of the cooling channel  314 . The flow restrictor  315  may be used to throttle the flow of a cooling fluid to provide efficient cooling within the cooling channels  314 . The cooling fluid may be a saturated refrigerant (e.g., dielectric refrigerants including, but not limited to, hydrofluorocarbons (HFC), hydrofluro-olefins (HFO), and/or hydrofluoroethers (HFE)). 
     The windings  310  may be wrapped about a support structure  316 . The support structure  316 , in some embodiments and as shown in  FIG.  3 B , may include a laminate portion  318  and a magnetic portion  320 . In some such embodiments, the laminate portion  318  may be formed from cobalt steel laminate and the magnetic portion  320  may be formed from a soft magnetic composite. The laminate portion  318  may be provided to capture in-plane flux from outer and inner rotor. The magnetic portion  320  may be provided to capture end rotor flux and may take a shape/filler in a gap through the end turns of the coil. The windings  310  include end connections  322  and may be electrically connected to one or more power module systems of the aircraft electric motor, such as shown above. 
     As shown in  FIG.  3 B , the magnets  306  are U-shaped and arranged within the rotor sleeve  306 . The rotor sleeve  306  is a substantially U-shaped sleeve that is sized and shaped to receive the U-shaped magnets  308 . In this illustrative configuration, the rotor sleeve  306  can include an inner sleeve  324 . The inner sleeve  324  may be configured to provide support to a portion of the magnets  308 . It will be appreciated that there is no direct contact between the windings  310  and the magnets  308 . This lack of contact enables free rotation of the rotor  302  relative to the stator  304  during operation. 
     High-power-density aviation-class electric motor and drives may require advanced cooling technologies. These machines are generally thermally limited at high power ratings and their performance can be improved by mitigating thermal limitations. In-slot cooling is an approach to directly cool the motor windings in the slot, leading to lower temperatures, and ultimately higher power density motors. However, manufacturing complexity arises when connecting many small parallel flow channels on one face of the motor. 
     In accordance with some embodiments of the present disclosure, in-slot cooling is achieved with oscillating heat pipes (OHPs) having an integrated cold plate to provide local cooling to the motor windings with less complexity than individual flow channels. Further, in accordance with embodiments of the present disclosure, a main fluid loop may have less pressure drop as compared to a configuration with fluid routed directly into slot channels. This has a system-level impact in that a pump and/or rejecting heat exchanger can be smaller and/or lighter in weight as compared to prior systems. In one non-limiting example, the OHPs are located in the motor slots, while an integrated cold plate is located externally to the motor slots. For example, the cold plate may be positioned at the axial face of the motor. During operation, the OHP (evaporator section of OHP) picks up heat inside of the motor windings. The heat is rejected at the cold plate side (condenser section of OHP). In some embodiments, the cold plate is integrated with a fluid loop to cool the condenser side of the OHP. In other embodiments, the cold plate section may take the form of a finned heat sink to be cooled with air. Such a system may be passively cooled. For example, passive cooling may employ air movement that is already present in a local environment. As such, in some embodiments, no power input is required to the system for the purpose of cooling and there may be few or no moving parts. As such reliability benefits may be realized in addition to improved cooling. In other configurations, a fan may be used to propel air over a heat sink, therefore introducing power input and moving parts. 
     Turning now to  FIG.  4   , a schematic illustration of a portion of an aircraft electric motor  400  in accordance with an embodiment of the present disclosure is shown. The aircraft electric motor  400  may be similar to that shown and described above, with components omitted for clarity and brevity of discussion. In  FIG.  4   , the aircraft electric motor  400  includes a stator  402  illustrating a single winding  403  (e.g., one winding  310  as shown in  FIGS.  3 A- 3 B ). It will be appreciated that  FIG.  4    is merely illustrative, and the stator  402  may include numerous windings arranged in an annular or circular structure, as shown and described above. The stator  402  may be arranged relative to a rotor and configured to induce rotation of the rotor, as described above. 
     To provide cooling to the windings  403 , each winding may be configured with one or more in-slot oscillating heat pipes  406  (in-slot OHP  406 ). Oscillating heat pipes (OHPs) use pressure-driven, two-phase fluid flow to rapidly transfer heat between heat sources and heat sinks. The in-slot OHP  406  includes an evaporator section  408  (e.g., evaporator portion or section) and a condenser section  410  (e.g., condenser portion or section) and contains a first working fluid  412  therein. The evaporator section  408  of the in-slot OHP  406  extends adjacent to the winding  403  (or between windings  403 ) and acquires heat from the windings  403  during operation of the aircraft electric motor  400 . As a working fluid (e.g., two-phase fluid) within the in-slot OHP  406  picks up heat, the heat will be transferred through the evaporator section  408  to the condenser section  410  through the oscillations of the first working fluid  412  within the evaporator section  408  of the in-slot OHP  406 . 
     The condenser section  410  of the in-slot OHP  406  extends into a cold plate  414 . The heat of the in-slot OHP  406  is rejected from the condenser section  410  into the cold plate  414 . The cold plate  414  includes the condenser section  410  of the in-slot OHP  406  and a heat pickup portion  416  of a cooling loop  418 . The heat pickup portion  416  of the cooling loop  418  may be integrated into the cold plate  414 . The heat pickup portion  416  may be formed of a plurality of channels formed in the cold plate  414  that contain a second working fluid  420 . In some embodiments, the second working fluid may be a coolant or refrigerant, and in some such embodiments may be a single-phase fluid. In some embodiments, the first working fluid  412  within the OHP  406  may be, for example and without limitation, ethanol, acetone, perfluorinated compounds (PFCs), and/or methoxy-nonafluorobutane, etc. Further, in some embodiments for example, and without limitation, the second working fluid  420  may be air, water, ethylene- or propylene-glycol, water mixtures (e.g., EGW, PGW), or a phase-change refrigerant. 
     The cooling loop  418 , in this embodiment, is an active cooling configuration. The second working fluid  420  picks up heat within the cold plate  414  from the condenser section  410  of the OHPs  406 . A pump  422  is used to provide motive force and drive the second working fluid  420  through the cooling loop  418 . The second working fluid  420  is pumped, using the pump  422 , through a heat exchanger  424  arranged along the cooling loop  418 . It will be appreciated that in other configurations, the pump may be downstream of the heat exchanger, and thus the illustrative configuration is not intended to be limiting. The heat exchanger  424  may be an air cooled heat exchanger, a fluid cooled heat exchanger, or the like. In some non-limiting embodiments, the heat exchanger  424  may be similar to the heat exchanger  226  shown in  FIGS.  2 A- 2 D . Heat within the second working fluid  420  is rejected at the heat exchanger  424  and then returned into the cold plate  414  to pick up heat from the condenser section  410  of the OHP  406 . 
     In some embodiments, the in-slot OHPs  406  may be integrally formed with the cold plate  414 . Similarly, at least the heat pickup portion  416  of the cooling loop  418  may also be integrally formed within the cold plate  414 . As such, a single unitary structure may include the OHPs  406 , the cold plate  414 , and a portion of the cooling loop  418 . In some embodiments, the pump  422  and the heat exchanger  424  may be fluidly coupled to the heat pickup portion  416  of the cooling loop  418  by one or more fluid ports  426  on the cold plate  414 . The cold plate  414  may include many different condenser sections  410  of different OHPs  406  and a single heat pickup portion  416  of the cooling loop  418 . In such a configuration, the heat pickup portion  416  may be formed of a flow channel or path that interweaves with the condenser sections  410  of the OHPs  406 . In some embodiments, the integrally formed cold plate  414  and OHPs  406  may serve a secondary function of structural support. That is, the OHPs  406  extends into and between the windings  403  and provides support thereto. Moreover, the cold plate  414  may provide structural support to the stator  402 . In accordance with some embodiments, the cold plate or heat sink can have different geometric profiles than that illustratively shown. For example, the in some embodiments, the cold plate may have a circle shape to match the shape of the motor. In some embodiments, the cold plate can include a hole, aperture, or open area in the center to make space for a motor shaft, motor end windings, and/or other motor components or associated components. 
     Although described as separate components, in some embodiments the OHPs may be integrally formed and embedded with the windings. That is, for example, the cooling channels  314  shown in  FIG.  3 B  which are integral and part of the windings  310  may be filled with a two-phase OHP working fluid. In such a configuration, the end connections  322  may be replaced by the condenser section of the OHPs and the end connections  322  may be part of an integral with a cold plate. 
     Turning now to  FIG.  5   , a schematic illustration of a portion of an aircraft electric motor  500  in accordance with an embodiment of the present disclosure is shown. The aircraft electric motor  500  may be similar to that shown and described above, with components omitted for clarity and brevity of discussion. In  FIG.  5   , the aircraft electric motor  500  includes a stator  502  illustrating a OHP  504  (e.g., a winding with embedded channels or a separate OHP adjacent windings of the stator  502 ). It will be appreciated that  FIG.  5    is merely illustrative, and the stator  502  may include numerous windings arranged in an annular or circular structure, as shown and described above. The stator  502  may be arranged relative to a rotor and configured to induce rotation of the rotor, as described above. 
     The OHP  504  includes a first working fluid  506  that oscillates within an evaporator section  508  to transfer heat to a condenser section  510  of the OHP  504 . The condenser section  510  is part of and integral with a cold plate  512 . In this embodiment, the cooling at the cold plate  512  is passive, as compared to the active pumping described with respect to the embodiment of  FIG.  4   . The condenser section  510  of the OHPs  504  extend into the cold plate  512  which includes a heat pickup portion  514 . The heat pickup portion  514 , of this embodiment, is formed of heat dispersion elements  516 . The heat dispersion elements  516  may be formed as fins, pedestals, plates, dimples, roughness, or similar structures, textures, surface features, etc. that provide an increased surface area to enable heat pick up by a second working fluid  518 . In this passive configuration, the second working fluid  518  may be air that is blown or convey over the heat dispersion elements  516  to remove heat from the heat pickup portion  514 . 
     Turning now to  FIGS.  6 A- 6 B , schematic illustrations of a portion of an aircraft electric motor  600  in accordance with an embodiment of the present disclosure is shown. The aircraft electric motor  600  may be similar to that shown and described above, with components omitted for clarity and brevity of discussion. In  FIGS.  6 A- 6 B , the aircraft electric motor  600  includes a stator  602  having windings  604  (shown in  FIG.  6 B ) arranged with OHPs  606  arranged relative thereto. As described above, in other embodiments, the OHPs may be formed as embedded channels within windings of the stator. It will be appreciated that  FIGS.  6 A- 6 B  are merely illustrative, and the stator  602  may include numerous windings arranged in an annular or circular structure, as shown and described above. The stator  602  may be arranged relative to a rotor and configured to induce rotation of the rotor, as described above. 
     As shown in  FIGS.  6 A- 6 B , the OHPs  606  include an evaporator section  608  and a condenser section  610  with a first working fluid  612  arranged therein. In this embodiment, rather than a cold plate, the cooling of the first working fluid is provided through a motor housing  614 . The motor housing  614 , in this embodiment, includes heat pickup portions  616  which are arranged relative to slots  618  within the motor housing  614 . A second working fluid  620  is passed through the slots  618  of the motor housing  614  to provide heat pick up and cool the first working fluid  612 . The motor housing  614  may operate substantially similar to the cold plates described above and provide structural support to the aircraft electric motor  600  in addition to the cooling properties provided through inclusion of the OHPs  606 . In the configuration illustrated in  FIGS.  6 A- 6 B , the cooling at the heat pickup portions  616  is passive and the second working fluid  620  (e.g., air) is passed through the slots  618 . In other embodiments, the slots  618  may be omitted and replaced by an active cooling scheme, such as plates or fins with a refrigerant or coolant that is passed through such structures using a pump and heat exchanger configuration, similar to that shown and described with respect to  FIG.  4   . 
     Referring now to  FIG.  7   , a power system  700  of an aircraft  702  is shown. The power system  700  includes one or more engines  704 , one or more electric motors  706 , a power bus electrically connecting the various power sources  704 ,  706 , and a plurality of electrical devices  710  that may be powered by the engines  704  and/or motors  706 . The power system  700  includes a power distribution system  712  that distributes power  714  through power lines or cables  716 . The electric motors  706  of the aircraft  702  may be configured similar to the aircraft electric motors shown and described above. 
     Advantageously, embodiments of the present disclosure provide for improved electric motors for aircraft and aviation applications. The aircraft electric motors of the present disclosure have improved cooling configuration that may improve cooling while eliminating or at least reducing the challenges with cooling windings of aircraft electric motors. For example, advantageously, embodiments of the present disclosure include integrated or integral oscillating heat pipes that provide an efficient mechanism for heat removal from windings of aircraft electric motors. Further, advantageously, the integral OHPs with cold plates or other structures can provide structural support or stability to the aircraft electric motors and/or components thereof. 
     The terms “about” and “substantially” are intended to include the degree of error associated with measurement of the particular quantity based upon the equipment available at the time of filing the application. For example, “about” or “substantially” can include a range of ±8% or 5%, or 2% of a given value. 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, element components, and/or groups thereof. 
     While the present disclosure has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the present disclosure. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the present disclosure without departing from the essential scope thereof. Therefore, it is intended that the present disclosure not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this present disclosure, but that the present disclosure will include all embodiments falling within the scope of the claims.