Motor methods and components

Abstract

The present disclosure provides an electric machine assembly, the electric machine assembly having: a main machine stator core, the main machine stator core having at least one stator column; a set of stator windings, the set of stator windings being wound on the at least one stator column and having a first end and an opposite second end; a coolant inlet housing, the coolant inlet housing defining an inlet channel; a coolant outlet housing, the coolant outlet housing defining an outlet channel, the outlet channel being adjacent to the coolant inlet housing, and wherein the coolant inlet channel and the coolant outlet channel define a coolant loop, the coolant loop being configured to receive a supply of coolant to remove heat generated in the set of stator windings.

Description

Technical Field

[0001] The present disclosure relates to electric machine methods and assemblies. Background Art

[0002] Contemporary aircraft engines include an electric motor assembly or generator system that provides electrical energy to power systems and components on the aircraft using the aircraft engine operating in generator mode. Some aircraft engines may further include a starter / generator (S / G) system or a motor / generator (M / G) that acts as an electric motor to start the aircraft engine from its high pressure spool or to drive the engine from the engine low pressure spool, and as a generator to provide electrical energy to power systems on the aircraft after the engine is running. The motor and generator may be a wet cavity system or a dry cavity system, wherein in the case of the wet cavity system, the cavity containing the rotor and stator is exposed to liquid coolant, while in the case of the dry cavity system, the cavity is not exposed to liquid coolant. Dry cavity cooling may also use liquid coolant in one or more contained cooling systems, but as long as the cavity is not exposed to liquid coolant, they will still be considered dry cavity. Generally speaking, dry cavity systems usually have lower losses, higher efficiency, higher reliability, less maintenance requirements and are attitude independent compared to wet cavity systems. Conversely, wet cavity motors may have higher power density than dry cavity motors due to their higher cooling efficiency. However, this may not be the case once multiple built-in cooling systems are applied to dry cavity motors. Summary of the invention

[0003] In one aspect, the present disclosure relates to an electric machine assembly, the electric machine assembly comprising: a main machine stator core, the main machine stator core having at least one stator post; a set of stator windings, the set of stator windings being wound on the at least one stator post and having a first end and an opposite second end, each of the first end and the second end extending through a common axial end of at least one stator post, the stator windings defining a fluid channel, the fluid channel being arranged to pass through the stator windings and configured to convey a coolant flow; a coolant inlet housing, the coolant inlet housing defining an inlet channel, the inlet channel being arranged at the common axial end of the electric machine assembly and being fluidly connected to the fluid channel at the first end of the set of stator windings; and a coolant outlet housing, the coolant outlet housing defining an outlet channel, the outlet channel being arranged at the common axial end of the electric machine assembly and being fluidly connected to the fluid channel at the second end of the stator windings.

[0004] In another aspect, the present disclosure is directed to a method of cooling a set of stator windings of an electric machine assembly, the method comprising supplying a coolant flow to an inlet channel of a coolant inlet housing disposed at a common axial end of a stator post of the electric machine assembly, the inlet channel being fluidly connected to a first end of a set of stator windings wound around the stator post and defining a closed fluid passage through the stator windings, conveying the coolant flow through the fluid passage of the stator windings, and receiving a return of the coolant flow from the fluid passage at a second end of the set of stator windings at an outlet channel of a coolant outlet housing disposed at the common axial end of the stator post. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] In the attached picture:

[0006] Figure 1 is a perspective view of a gas turbine engine with a generator according to various aspects described herein.

[0007] Figure 2 According to the various aspects described in this specification Figure 1 A perspective view of the exciter of the generator is shown.

[0008] Figure 3 is a schematic cross-sectional view of a generator according to various aspects described in this specification, wherein Figure 2 The line III-III in FIG. 1 intercepts and shows the structure of the generator.

[0009] Figure 4 According to the various aspects described in this specification Figure 3 An enlarged schematic diagram of the generator shown.

[0010] Figure 5is a schematic cross-sectional view of a generator according to various aspects described in this specification, wherein a cooling system of the generator is shown.

[0011] Figure 6 According to the various aspects described in this specification Figure 3 Schematic cross-section of the stator winding of the generator shown.

[0012] Figure 7 According to the various aspects described in this specification Figure 3 Schematic diagram of the stator winding and cooling system of the generator shown. DETAILED DESCRIPTION

[0013] Aspects of the present disclosure may be implemented in any environment where a generator or motor is used, whether the generator or motor is providing driving force or generating electricity. For purposes of this specification, the motor will be collectively referred to as a motor, motor assembly, generator, or similar language, with the intent to clarify that the machine may include one or more stator / rotor combinations.

[0014] Although "a set" of various elements will be described in this specification, it should be understood that a "set" may include any number of corresponding elements, including only one element. The terms "axial" or "axially" as used in this specification refer to a dimension along the longitudinal axis of the motor, or along the longitudinal axis of a component disposed within the motor. The terms "radial" or "radially" as used in this specification refer to a dimension extending between the central longitudinal axis of the motor, the outer rotational circumference, or a circular or annular component disposed within the motor. The terms "proximal" or "proximal" alone or in combination with the terms "radial" or "radially" refer to movement in a direction toward the central longitudinal axis, or a component being relatively closer to the central longitudinal axis than another component.

[0015] All directional terms (e.g., radial, axial, up, down, upward, downward, left, right, lateral, front, back, top, bottom, above, below, vertical, horizontal, clockwise, counterclockwise) are used only for identification purposes to help the reader understand the present disclosure and are not intended to be limiting, particularly with respect to position, orientation, or use. Connectivity terms (e.g., attach, connect, connect, and engage) should be interpreted broadly and, unless otherwise specified, may include intermediate members between a set of elements and relative movement between such elements. Thus, connectivity terms do not necessarily imply that two elements are directly connected to each other and are fixed relative to each other. The exemplary drawings are for illustration only, and the sizes, positions, orders, and relative sizes reflected in the associated drawings may be changed.

[0016] Although the present description is primarily directed to electric machines that provide power generation, it is also applicable to electric machines that provide drive power or electric machines that provide both drive power and power generation. In addition, although the present description is primarily directed to an aircraft environment, aspects of the present disclosure are also applicable to any environment in which electric machines are used. Therefore, a brief overview of the intended environment may help to more fully understand the present invention.

[0017] Figure 1 A gas turbine engine 10 is shown according to one aspect of the present disclosure, the gas turbine engine having an accessory gearbox (AGB) 12 and a generator 14. The gas turbine engine 10 may be a turbofan engine commonly used in modern commercial and military aviation, such as the General Electric GEnx or CF6 series engines, or various other known gas turbine engines, such as turboprop engines or turboshaft engines. The gas turbine engine 10 may also have an afterburner, which burns an additional amount of fuel downstream of the low-pressure turbine region to increase the velocity of the exhaust gases and thereby increase thrust. The AGB 12 may be connected to a turbine shaft (not shown) of the gas turbine engine 10 via a mechanical power takeoff 16. The gas turbine engine 10 may be any suitable gas turbine engine used in modern commercial and military aviation, or various other known gas turbine engines, such as turboprop engines or turboshaft engines. The type and details of the gas turbine engine 10 are not germane to the present disclosure and will not be further described in this specification. Although a generator 14 is shown and described, aspects of the present disclosure may include any motor, generator, motor, starter / generator combination, and are not limited to generator aspects that can provide electrical power. For example, in one non-limiting example, the generator may be operated in a generating mode to provide power, or in a motor mode where power is consumed to produce a rotational force, such as propulsion. Non-limiting examples of the generator 14 may include a synchronous motor architecture.

[0018] Figure 2 1 and 18. A plurality of electrical connections may be provided on the exterior of the generator 14 to enable power input to and power output from the generator 14. The electrical connections may be further connected to a power distribution node of an aircraft having the gas turbine engine 10 via cables to power various devices on the aircraft, such as lights and seat back monitors.

[0019] Non-limiting aspects of the present disclosure may be included, where, for example, a clamping interface may be included, and the clamping interface is used to clamp the generator 14 to the AGB 12. In another non-limiting aspect of the present disclosure, the generator 14 may include a liquid coolant system for cooling or dissipating heat generated by components of the generator 14 or components near the generator 14, such as the gas turbine engine 10. For example, the generator 14 may include a liquid cooling system using oil as a coolant. The liquid cooling system may include a cooling fluid inlet and a cooling fluid outlet (not shown) for controlling the supply of coolant to the generator 14. In yet another non-limiting aspect of the present disclosure, the generator 14 may further include other liquid cooling system components, such as a liquid coolant reservoir in fluid communication with the cooling fluid inlet or the cooling fluid outlet, or a liquid coolant pump that forcibly supplies coolant through the inlet and outlet or the generator 14. Oil is only one non-limiting example of a liquid coolant that can be used in various aspects of the present disclosure. Additional or alternative types of fluid coolants may be included in aspects of the present disclosure, including but not limited to liquids, gases, fluids, or combinations thereof.

[0020] The interior of the generator 14 is Figure 3 The easiest to see is Figure 3 yes Figure 2 A first cross-sectional view of the generator 14 is shown. A rotatable shaft 40 is located within the generator 14 and is the primary structure for supporting various components. The rotatable shaft 40 may have a single diameter, or the diameter may vary along its length. The rotatable shaft 40 is supported by spaced bearings 42 and 44 and is configured to rotate about an axis of rotation 41. Several elements of the generator 14 have fixed components and rotating components, wherein the rotating components are disposed on the rotatable shaft 40. Examples of these elements may include a main engine 50, an exciter 60, and a permanent magnet generator (PMG) 70 housed in a main engine cavity 51. The corresponding rotating components include a main engine rotor 52, an exciter rotor 62, and a PMG rotor 72, respectively, and the corresponding fixed components include a main engine stator 54 or stator core, an exciter stator 64, and a PMG stator 74.

[0021] As shown, aspects of the exciter 60 and the PMG 70 can be coplanar with the plane 22, which is orthogonal or perpendicular to the axis of rotation 41. In this sense, non-limiting aspects of the exciter 60, such as the exciter rotor 62 or the exciter stator 64, or aspects of the PMG 70, such as the PMG rotor 72 or the PMG stator 74, can be coplanar at the orthogonal plane 22. Also as shown, the exciter 60, the exciter rotor 62, or the exciter stator 64 can be disposed along an outer radius of the PMG 70, the PMG rotor 72, or the PMG stator 74. Thus, the exciter 60 can be located radially outward of the PMG 70 relative to the axis of rotation 41.

[0022] Although illustrated aspects of the disclosure are shown wherein the exciter 60 and PMG 70 components are co-disposed at an orthogonal plane 22, aspects of the disclosure may be included wherein the exciter 60 and PMG 70 components are substantially co-planar with each other, or with a single orthogonal plane 22. Other aspects of the disclosure may be included wherein aspects of the exciter 60 and PMG 70 components are configured, arranged, disposed, or the like in a co-planar relationship wherein at least a portion of the exciter 60 or PMG 70 axially overlaps the other component along the axis of rotation 41. Thus, “substantially co-planar” is not limited to exact planar representations, and may include any overlap between the respective components 60, 70 along an axial segment.

[0023] The generator 14 may also include an arm 24 disposed on the rotatable shaft 40 and configured to rotate with the shaft 40. The arm 24 may also provide mounting for at least one of the PMG rotor 72 and the exciter rotor 62. Non-limiting aspects of the present disclosure may be included in which the other of the PMG rotor 72 or the exciter rotor 62 may be directly mounted to the rotatable shaft 40 in a rotatable manner. In another non-limiting aspect of the present disclosure, both the PMG rotor 72 and the exciter rotor 62 may be rotatably mounted to the arm 24. The arm 24 may include a segment 26 that extends radially away from the rotatable shaft 40 such that the arm 24 or segment 26 has a larger radius than the rotatable shaft 40, wherein the radius is measured from the axis of rotation 41. Non-limiting aspects of the present disclosure may be included in which the arm 24 or segment 26 may include a group of arms 24 or segments 26 that are radially spaced around the rotatable shaft 40. The set of arms 24 or segments 26 may be radially spaced based on a desired rotational balance between the exciter rotor 62, the PMG rotor 72, the permanent magnets, the number of poles of the exciter rotor 62 or the PMG rotor 72, the set of arms 24, the set of segments 26, or a combination thereof.

[0024] In another non-limiting aspect of the present disclosure, the arm 24 or segment 26 may include a continuous arm 24 or segment 26, wherein the arm 24 or segment 26 extends continuously (e.g., without radial interruptions or radial gaps) around the rotation axis 41. In this non-limiting aspect of the present disclosure, the exciter rotor poles, the PMG rotor poles, or permanent magnets may be arranged, arranged, radially spaced, or the like based on a number of poles, arms 24, segments 26, or combinations thereof of the exciter rotor 62, the PMG rotor 72, the permanent magnets, the exciter rotor 62, or the PMG rotor 72.

[0025] Although the illustrated examples show aspects of the exciter rotor 62, exciter stator 64, PMG rotor 72, and PMG stator 74 in the same cross-sectional view for ease of understanding, aspects of the disclosure may be included in which the exciter rotor 62, exciter stator 64, PMG rotor 72, or PMG stator 74 are radially offset from the other components. For example, in one non-limiting aspect, the PMG rotor 72 may be radially offset from the exciter rotor 62 to reduce, prevent, or eliminate magnetic interference between the respective components. In another non-limiting aspect of the disclosure, aspects of the exciter 60 or PMG 70 may be electromagnetically shielded from the corresponding components, such as radially isolating the exciter 60 from the PMG 70 to reduce, prevent, or eliminate magnetic interference between the respective components.

[0026] In this manner, the main machine rotor 52, the exciter rotor 62, and the PMG rotor 72 are disposed on or rotatably supported by the rotatable shaft 40, such as directly supported by the shaft 40 or indirectly supported by the shaft 40, as described above with respect to the arm 24. Stationary components such as the main machine stator 54, the exciter stator 64, or the PMG stator 74 may be mounted to any suitable portion of the housing 18 so that relative rotation of the rotor components may electromechanically interact with the respective stator components 54, 64, 74. The main machine stator 54, the exciter stator 64, and the PMG stator 74 define an interior through which the rotatable shaft 40 extends.

[0027] It should be understood that the main machine rotor 52, the exciter rotor 62, and the PMG rotor 72 can have a set of rotor poles, including but not limited to two rotor poles, and the main machine stator 54, the exciter stator 64, and the PMG stator 74 can have a set of stator teeth or stator poles, including but not limited to two stator teeth or stator poles. The set of rotor poles can generate a set of magnetic fields relative to the set of stator poles, so that the generator 14 can operate through the interaction of the magnetic field with the current-carrying conductor to generate force or electricity. The exciter 60 can provide direct current to the main machine 50, and the main machine 50 and the PMG 70 can supply alternating current (AC) power when the rotatable shaft 40 rotates.

[0028] The rotor poles and at least one of the stator teeth and stator poles can be formed by a core having a column and a wire wound on the column to form a winding, wherein the winding has at least one end turn. The illustrated aspects of the present disclosure include at least one set of stator windings 90 arranged longitudinally along the stator housing 18, i.e., parallel to the housing 18 and the rotor rotation axis 41. The set of stator windings 90 can also include a set of stator winding end turns 92, which extend axially beyond the opposite ends of the longitudinal length of the main machine stator 54.

[0029] The components of the generator 14 can be any combination of known generators. For example, the main engine 50 can be a synchronous generator or an asynchronous generator. In addition to the accessories shown in this aspect, other components may also need to be operated in a specific application. For example, in addition to the electromechanical accessories shown, other accessories may also be driven by the same rotatable shaft 40, such as a liquid coolant pump, a fluid compressor, or a hydraulic pump.

[0030] For ease of understanding, Figure 4 An enlarged view of the generator 14 is shown to better understand the operation and effect of the substantially co-planar exciter 60 and PMG 70 .

[0031] By arranging, setting, positioning or similarly arranging aspects of the exciter 60 and the PMG 70 in a generally coplanar relationship, such as near the plane 22 or along the axial direction of the rotation axis 41, the overall length of the rotatable shaft 40 can be reduced relative to a generator, motor or the like, wherein the exciter 60 and the PMG 70 are arranged in series or in sequence along the axial direction of the rotation axis. By reducing the overall length of the rotatable shaft 40, the structure of the generator 14 measured in terms of volume, length, size, compactness, displacement, etc. can be reduced. In this sense, reducing the size of the generator 14 will increase the power density of the generator 14 compared to a similarly positioned motor in which the exciter 60 and the PMG 70 are arranged in series or in sequence along the axial direction of the rotation axis.

[0032] As described above, the generator 14 may be oil cooled and may include a cooling system. The cooling oil may be used to dissipate heat generated by the electrical and mechanical functions of the generator 14. Figure 5 A non-limiting exemplary cooling system 80 is shown. Figure 5 Shown with Figure 3 80 to better illustrate aspects of the cooling system 80. In one example, aspects of the cooling system 80 can use oil based on, for example, expected cooling capacity, high specific heat, high heat capacity, or expected viscosity (e.g., for pumping purposes). In another example, the cooling oil can also provide lubrication for the generator 14. In the illustrated aspects of the present disclosure, the generator 14 can be a dry cavity system with liquid cooling, the dry cavity system having a cooling system 80, which is shown to include a cooling fluid inlet 82 and a shaft outlet 91 for controlling the supply of cooling fluid to the cooling system 80.

[0033] The cooling system 80 may further include, for example, a cooling fluid reservoir and various cooling channels. The rotatable shaft 40 may provide one or more flow channels or passages for the main engine rotor 52, the exciter rotor 62, and the PMG rotor 72. In one non-limiting example aspect of the cooling system 80, the rotatable shaft 40 may define an interior 84 that receives a cooling oil flow (as shown by arrow 85), which may be further pumped, transported, delivered or transferred to another cooling channel. In another non-limiting aspect of the cooling system 80, the arm 24 or segment 26 may include a first cooling channel 100, which is configured or arranged to transmit the cooling oil flow through the arm 24 or segment 26. The first cooling channel 100 may be operably configured to heat the heat generated in the components (including but not limited to the exciter rotor 62, the PMG rotor 72, or a combination thereof) supported in a rotatable manner, and transfer the heat to the cooling oil to remove the heat. In yet another non-limiting aspect of the cooling system 80, the main engine rotor 52 may include a second cooling channel 102 configured or arranged to convey a cooling oil flow through the main engine rotor 52. The second cooling channel 102 may be operably configured to thermally receive heat generated in the main engine rotor 52 and transfer the heat to the cooling oil to remove the heat. The heated oil, remaining oil, unused oil, or unspent oil may be discharged from the rotatable shaft 40 and provided to an outlet, such as the rotor shaft oil outlet 88 or the shaft outlet 91.

[0034] Non-limiting aspects of the present disclosure may be included, wherein the first cooling channel 100 or the second cooling channel 102 may be radially spaced around the rotatable shaft 40. The first cooling channel 100 or the second cooling channel 102 may be radially spaced based on an expected rotational balance or a set of expected heat removal characteristics. For example, in one non-limiting aspect, the first cooling channel 100 or the second cooling channel 102 may be disposed close to a corresponding host 50, exciter 60 or PMG 70 heat generating component to ensure reliable thermal coupling.

[0035] As shown, non-limiting aspects of the cooling system 80 may further include a cooling circuit for a set of stator windings 90 of the main machine stator 54. For example, at least one set of stator windings 90 may be wound on the main machine stator 54.

[0036] A problem with conventional wet cavity or dry cavity generators is that conventional cooling systems have difficulty removing heat generated by at least one of the main machine stator and the set of stator windings, wherein the set of stator windings is arranged or positioned closer to the axial center of the stator. Residual heat near the axial center of the main machine stator or the set of stator windings can cause reduced generator performance or output. For example, stator core losses caused by hysteresis or eddy currents occurring during generator operation may generate unwanted heat. In a non-limiting example, a conventional generator can solve this problem by including a low thermal conductivity layer (e.g., about 0.12 Watts / degree Celsius-meter; "W / mC") between the stator and the stator windings to conduct a small portion of the heat from the stator to the windings, while an external cooling jacket heat discharges most of the heat from the stator. A conventional external cooling jacket includes a coolant channel surrounding at least a portion of the main machine stator, wherein the jacket coolant channel is in fluid communication with a liquid coolant source. The liquid coolant passing through the cooling jacket provides cooling to ensure the intended generator operation, but adding a cooling system increases cost, complexity, and increases the weight and size requirements of the generator system.

[0037] Aspects of the present disclosure provide an alternative solution to address the cooling of at least the main machine stator 54, the set of stator windings 90, or a combination thereof by using a dedicated configuration of the main machine stator windings 90, wherein the dedicated configuration includes a third cooling channel 104 disposed through the windings 90 and configured to convey a cooling oil flow through at least a subset of the stator windings 90. The third cooling channel 104 can be operably configured to thermally receive heat generated in the main machine stator 54 or the set of stator windings 90 and transfer the heat to the cooling oil to remove the heat. In one non-limiting aspect, the first end of the set of stator windings or the third cooling channel 104 can be in fluid communication with the oil flow through, for example, a stator winding coolant inlet housing 122, wherein the stator winding coolant inlet housing defines an inlet channel 106, which is connected to at least a subset of the stator windings 90 to axially extend beyond the stator winding end turns 92. Heated oil, residual oil, unused oil, or unspent oil may be discharged from at least a subset of the stator windings 90 through a stator winding coolant outlet housing 124, wherein the stator winding coolant outlet housing defines an outlet passage 108, which may also be located axially beyond the stator winding end turns 92, for example. The stator winding outlet passage 108 may further be connected to an oil outlet of the generator 14, such as a rotor shaft oil outlet 88 or a shaft outlet 91. Aspects of the present disclosure may be included in which the coolant inlet housing 122 and the coolant outlet housing 124 are axially spaced from one another. At least one of the coolant inlet housing 122 and the coolant outlet housing 124 may be in the form of a pancake or annular configuration relative to the rotation axis 41.

[0038] Although the set of stator windings 90 is schematically shown, multiple sets of stator windings 90 may be included or each stator core slot may include multiple sets of stator windings 90. For example, in one non-limiting example, at least two sets of stator windings 90 may be stacked, layered, embedded, mounted or wound on the stator core slot. Non-limiting aspects of the present disclosure may also be included, wherein at least a subset of the stator windings 90 may include an outer layer of electrically insulating material for electrically insulating the set of stator windings 90 from another set of stator windings 90 or the host stator 54 or stator core.

[0039] Figure 6 A simplified schematic diagram of an exemplary set of stator windings 90 according to aspects disclosed in the present specification is shown. For example, the set of stator windings 90 may include an electrically conductive winding having a fluid channel disposed throughout the entire length of the winding 90. In the illustrated example, the set of stator windings 90 may include a generally square or quadrilateral cross-section having a working liquid or fluid channel 116. Non-limiting aspects of the present disclosure may also be included, wherein the set of stator windings 90 includes a layer of electrically insulating material 118, which is located outside the set of stator windings 90 and encloses the set of stator windings to electrically insulate the set of stator windings 90 from another set of stator windings 90 and the host stator 54, as described above. Although the windings 90 are illustrated as having a generally square cross-section, any geometric shape, profile, etc. (e.g., rectangular, circular, trapezoidal, triangular, etc.) may be used in aspects of the present disclosure. Likewise, although circular fluid passages 116 are illustrated, any geometric shape, profile, etc. (eg, rectangular, circular, trapezoidal, triangular, etc.) may be used in aspects of the present disclosure.

[0040] Although a generally rectangular cross-section of the stator winding 90 is shown, any geometric cross-section may be included in aspects of the present disclosure, including but not limited to circular, oval, square, etc. Likewise, although only a single working fluid channel 116 is shown in cross-sectional view AA, aspects of the present disclosure may include a set of fluid-isolated working fluid channels 116 in a single set of stator windings 90. For example, a single oval or rectangular cross-section of the set of stator windings 90 may include parallel or dual working fluid channels 116. In one non-limiting example aspect of the set of stator windings 90, the diameter of the working fluid channel 166 may be 1.0 mm to 2.0 mm.

[0041] Figure 7A non-limiting example aspect of the stator windings 90 and the third cooling passage 104 is shown. As shown, at least a subset of the stator windings 90 includes a first end 126 of the windings 90 and an opposite second end 128 of the windings 90. At least a subset of the stator windings 90 may pass through or be adjacent to at least one of the stator winding inlet housing 122 and the coolant outlet housing 124. At least one of the stator winding inlet housing 122 and the coolant outlet housing 124 may also include a central hole 120 or through-hole configured to receive or mate with a rotatable shaft (not shown). Non-limiting aspects of the present disclosure may be included, wherein at least one of the stator winding inlet passage 106 and the coolant outlet passage 108 may be in fluid communication with a rotatable shaft coolant flow as described herein. In another example of the illustrated non-limiting example, the first end 126 of the subset of stator windings 90 may extend through or near the stator winding inlet housing 122 and the coolant outlet housing 124 and be connected to an electrical terminal or power output of the generator 14. In the first example, the stator windings 90 may be in fluid communication with the stator winding inlet passage 106 through, for example, the orifice 112 to fluidly receive the coolant (illustrated with a cross section of the coolant inlet housing 122 removed to schematically illustrate the inlet passage 106 as an arrow and across toward the main machine stator). In this first example, the stator windings 90 may pass through the coolant outlet housing 124 via the through passage 110, which is not in fluid communication with the coolant outlet passage 108.

[0042] In another example, another stator winding 90 section may be in fluid communication with the stator winding coolant outlet passage 108 via, for example, an orifice 112 to fluidly provide heated coolant from the main engine stator to the coolant outlet passage 108 (again, illustrated as a cross section with the coolant outlet housing 124 removed to schematically illustrate the outlet passage 108 as an arrow). In this other example, the stator winding 90 may pass through the coolant inlet housing 122 via a through passage 110 that is not in fluid communication with the coolant inlet housing 122. "Heated coolant" as used in this specification may convey that the coolant is removing or has removed heat from an upstream component. The coolant inlet passage 106 and the coolant outlet passage 108 may be further fluidly connected to a coolant circuit or a coolant reservoir.

[0043] During power generation operation, the rotation of the rotatable shaft 40 relative to the fixed generator 14 components will ultimately induce current in the main engine stator winding 90, which is further provided to the generator power outlet, which in turn can be supplied to power or provide energy to a set of electrical loads. Specifically, the rotation of the exciter rotor 62 relative to the exciter stator 64, the rotation of the PMG rotor 72 relative to the PMG stator 74, and the rotation of the main engine rotor 52 relative to the main engine stator 54 will generate heat due to heat losses, copper losses, resistance losses, winding losses, etc. that occur when current passes through the corresponding resistance windings. As described in this specification, in addition to winding losses, the above-mentioned components 52, 54, 62, 64, 72, 74 may generate or retain unwanted heat due to core losses caused by, for example, hysteresis or eddy currents. For example, as described above, heat of the main engine stator 54 can be generated or retained at the axial end facing away from the stator 54.

[0044] The cooling system 80 can implement or provide dry cavity-based cooling through at least the first cooling channel 100, the second cooling channel 102, and the third cooling channel 104 or a subset thereof to conduct heat from the heated component to a cooling liquid, such as cooling oil. In this sense, the heat generated in the corresponding component can be conducted to the cooling liquid (i.e., "hot" liquid) of the cooling system 80, and the cooling liquid can be forcibly pumped out of the heat-generating component.

[0045] In one non-limiting aspect of the present disclosure, at least a subset of the above-described cooling systems 80 can effectively remove, extract, or transfer more than 39 kW of heat from a generator 14 rated at 150 kVA or higher without encountering heat transfer limitations. In yet another non-limiting aspect of the present disclosure, the above-described configuration can be used in a generator 14 to achieve a power density greater than 7.9 kW / kg.

[0046] The above aspects of the present invention enable or enable the generator 14 to have a higher cooling capacity than contemporary generators. Since aspects of the present disclosure significantly improve the cooling capacity of the main engine stator 54 or a set of stator windings 90 and the cooling capacity of the PMG rotor 72, the exciter rotor 62 or a combination thereof, the generator 14 can be designed or operated so that there is no or no additional cooling system outside the generator 14 except for the cooling system 80 described in this specification. For example, aspects of the present disclosure can provide a dry cavity generator 14, wherein the system can be designed or operated so that there is no or no additional cooling system is set outside the generator 14, so that the system provides cooling greater than or equal to a predetermined level, wherein the predetermined level is based on the external liquid cooling jacket. Alternatively or in addition to the above benefits, the above aspects enable or enable the generator 14 to operate at a higher power density or produce a higher power level without causing a loss of power generation efficiency due to unnecessary heating.

[0047] By operating the cooling system 80 to achieve or provide enhanced cooling capabilities and thereby provide higher power generation operating capabilities, the generator 14 can further achieve or enable a higher overall power density compared to a conventional motor, wherein the exciter and PMG are arranged in series or in sequence along the axial direction of the rotation axis. When combined together (coplanar exciter 60 and PMG 70 together with the cooling system 80 described in this specification), the power density of the generator 14 can be equal to or greater than twice the power density of a conventional motor. In one non-limiting example, the generator 14 described in this specification can generate at least 1 megawatt of electrical power using the aspects described in this specification.

[0048] Yet another advantage of the above aspects may include improved efficiency of the cooling system. For example, wet cavity type cooling is an effective cooling strategy for the generator, but is less efficient than dry cavity cooling as described herein. In another non-limiting example, wet cavity cooling can be inefficient due to the interaction of the oil with the moving parts in the cavity, which can result in significant dynamic losses in the generator. Aspects of the present disclosure may provide a dry cavity generator configuration that includes efficient cooling and high power density.

[0049] In one non-limiting example, a generator employing aspects of the present disclosure may include a power density of 7.9 kW / kg or greater than 7.0 kW / kg. A conventional generator with an exciter and PMG arranged in series (ie, not coplanar) may include a power density of 3.3 kW / kg.

[0050] Aspects of the generator 14 described herein may also be included in a method of operating the generator 14. For example, the method of operating the generator 14 may include rotating a rotatable shaft 40 about an axis of rotation 41, wherein the shaft 40 carries an arm 24, the arm extending radially outward from the shaft 40. The arm 24 may be configured to rotatably carry at least one of an exciter rotor 62, a permanent magnet generator rotor 72, or both rotors 62, 72. At least one of the exciter rotor 62 and the permanent magnet generator rotor 72 is mounted to the arm 24 and is substantially coplanar at a plane 22 orthogonal to the axis of rotation 41. In one non-limiting aspect of the present disclosure, the method may optionally include supplying a liquid coolant to a built-in cooling channel, such as a first cooling channel 100 of the arm 24, to extract heat from the arm 24. In another non-limiting aspect of the present disclosure, the method may include supplying liquid coolant to built-in cooling channels, such as the third cooling channels 104 , to extract heat from at least one set of stator windings 90 , wherein the built-in cooling channels extend through the at least one set of stator windings 90 .

[0051] The method described is for illustrative purposes only and is not meant to limit the method in any way, as it is understood that parts of the method may be performed in a different logical order, may include additional or intermediate parts, or the described parts of the method may be divided into multiple parts, or parts of the method may be omitted without detracting from the method.

[0052] Although the above aspects have been described from the perspective of a generator for a gas turbine engine, the above aspects can be used in any electric machine to significantly increase stator or rotor power generation or cooling capabilities. The above aspects of the present disclosure can be very suitable for certain generator applications, such as a two-pole generator (e.g., two stator poles and two rotor poles) located near a turbine engine and thus creating a generator operating environment that is subject to high temperatures and space or volume constraints.

[0053] Many other possible aspects and configurations other than those shown in the above-mentioned figures are covered in the present disclosure. For example, the set of stator windings may include one or more sets of stator windings connected in sequence, wherein the set of stator windings are electrically connected to each other. In another aspect of the present disclosure, it should be understood that the hollow portion of the set of stator windings and the coolant flow passing therethrough may also be applied to the winding portion of the exciter 60, PMG 70, main machine 50, or a combination thereof. In addition, the design and arrangement of the various components can be rearranged so that many different in-line configurations can be achieved. For example, aspects of the present disclosure may be included in which the PMG 70 is located radially outside the exciter 60. In yet another non-limiting aspect, at least one of the main machine rotor, main machine stator, housing, and rotatable shaft may be manufactured by additive manufacturing or three-dimensional printing. Additive manufacturing may further be used for at least one of the cooling channels.

[0054] The above aspects provide a variety of benefits, including higher efficiency, higher reliability, less maintenance, full-state operation, and lighter weight. By increasing the cooling capacity of the dry cavity motor without providing a cooling system external to the motor in addition to the cooling system described in this specification, the motor can eliminate the additional cost, complexity, weight, and size requirements required for an additional cooling system. The resulting motor is lighter, smaller, and has lower complexity than a conventional dry cavity motor. The resulting motor also has a higher power density due to at least one of the following items: a reduction in the axial length of the rotatable shaft, an increase in power generation capacity due to improved cooling capacity, or a combination thereof. The weight reduction, increased cooling capacity, or increased power density is critical in a turbine engine environment and can provide a competitive advantage during flight. The reduced complexity can also correspond to reduced maintenance over time, thereby also providing lower operating costs.

[0055] To the extent not already described, different features and structures of various aspects may be combined with other features and structures as desired. The failure to describe a feature in some aspects should not be construed as an inability to include the method in the aspects, but is described as such for the purpose of brevity. Thus, various features of different aspects may be mixed and matched as desired to form new aspects, whether or not the new aspects are explicitly described.

[0056] Further aspects of the invention are provided by the subject matter of the following clauses:

[0057] 1. A motor assembly, comprising:

[0058] A main engine stator core, wherein the main engine stator core has at least one stator column;

[0059] a set of stator windings wound around the at least one stator post and having a first end and an opposing second end, each of the first end and the second end extending beyond a common axial end of the at least one stator post, the stator windings defining a fluid passage disposed through the stator windings and configured to carry a flow of a coolant;

[0060] a coolant inlet housing defining an inlet passage disposed at a common axial end of the electric machine assembly and in fluid communication with the fluid passage of the first end of the set of stator windings; and

[0061] A coolant outlet housing defines an outlet passage disposed at the common axial end of the electric machine assembly and in fluid communication with the fluid passage at the second end of the stator winding.

[0062] 2. The electric machine assembly according to clause 1, wherein the coolant inlet housing and the coolant outlet housing are arranged to extend axially beyond the longitudinal length of the main machine stator core.

[0063] 3. The electric machine assembly of clause 2, wherein the coolant inlet housing defines a first through-passage sized and configured to receive the stator winding through the second end of the first through-passage.

[0064] 4. The electric machine assembly of clause 3, wherein the coolant outlet housing defines a second through-passage sized and configured to receive the stator winding through the first end of the first through-passage.

[0065] 5. The motor assembly according to clause 2, wherein a second end of the stator winding extends beyond the first through-channel and is connected to an electrical terminal.

[0066] 6. An electric machine assembly according to any one of clauses 1 to 5, wherein the coolant inlet housing and the coolant outlet housing are axially spaced apart.

[0067] 7. An electric machine assembly according to any of clauses 1 to 5, wherein at least one of the coolant inlet housing or the coolant outlet housing is in the form of a flat coolant housing.

[0068] 8. An electric machine assembly according to any of clauses 1 to 5, wherein at least one of the coolant inlet housing or the coolant outlet housing is in the form of an annular coolant housing.

[0069] 9. An electric machine assembly according to any one of clauses 1 to 5, wherein the coolant is at least one of oil or air.

[0070] 10. A motor assembly according to any one of clauses 1 to 5, wherein the motor assembly is a dry cavity motor assembly.

[0071] 11. An electric machine assembly according to any one of clauses 1 to 5, wherein the set of stator windings has a generally quadrilateral cross-section.

[0072] 12. An electric machine assembly according to any one of clauses 1 to 5, further comprising an electrically isolating material externally enclosing the set of stator windings.

[0073] 13. An electric machine assembly according to any of clauses 1 to 5, wherein the set of stator windings defines at least two fluid channels per winding.

[0074] 14. A motor assembly according to any one of clauses 1 to 5, wherein the diameter of the fluid channel is between 1.0 mm and 2.0 mm.

[0075] 15. An electric machine assembly according to any of clauses 1 to 5, wherein the coolant inlet passage, the fluid passage of the stator windings and the coolant outlet passage define a coolant circuit configured to receive a supply of coolant to remove heat generated in a set of stator windings.

[0076] 16. A method of cooling a set of stator windings of an electric machine assembly, the method comprising:

[0077] supplying a coolant flow to an inlet passage of a coolant inlet housing disposed at a common axial end of a stator post of the electric machine assembly, the inlet passage being fluidly connected to a first end of a set of stator windings wound around the stator post and defining a closed fluid passage through the stator windings;

[0078] delivering the coolant flow through fluid passages of the stator windings; and

[0079] A return of the coolant flow from the fluid passage is received at a second end of the set of stator windings at an outlet passage of a coolant outlet housing disposed at a common axial end of the stator post.

[0080] 17. The method of clause 16, wherein supplying, delivering and receiving the coolant flow is configured to remove heat generated in the set of stator windings.

[0081] 18. The method of any of clauses 16 to 17, further comprising generating an electric current in the set of stator windings and supplying the generated electric current to a set of electrical terminals disposed at a common axial end of the stator post.

[0082] 19. The method of clause 18, wherein the set of electrical terminals is further disposed axially through at least one of the coolant inlet housing or the coolant outlet housing, opposite the stator post.

[0083] 20. The method according to any of clauses 16 to 17, wherein supplying the coolant flow comprises supplying the coolant flow to the coolant inlet housing in the form of an annular coolant housing or a flat coolant housing.

[0084] This specification uses examples to disclose the invention, including the best mode, and also enables any technician in the field to practice the invention, including making and using any device or system, and implementing any method covered. The scope of patent protection for the present disclosure is defined by the claims and may include other examples that come to mind for technicians in the field. If the structural elements of other such examples are the same as the literal meaning of the claims, or if such examples include equivalent structural elements that are not substantially different from the literal meaning of the claims, such examples should also be within the scope of the claims.

Claims

1. A motor assembly, comprising: A main engine stator core, wherein the main engine stator core has at least one stator column; a set of stator windings wound around the at least one stator post and having a first end and an opposing second end, each of the first end and the second end extending beyond a common axial end of the at least one stator post, the stator windings defining a fluid passage disposed through the stator windings and configured to carry a flow of a coolant; a coolant inlet housing defining an inlet passage disposed at a common axial end on one side of the electric machine assembly and in fluid communication with the fluid passage at the first end of the set of stator windings; as well as a coolant outlet housing defining an outlet passage disposed at a common axial end on the other side of the motor assembly and in fluid communication with the fluid passage at the second end of the stator winding, wherein the coolant inlet housing and the coolant outlet housing are axially spaced apart, The coolant is at least one of oil or air. 2 . The motor assembly according to claim 1 , wherein the coolant inlet housing and the coolant outlet housing are disposed to extend beyond a longitudinal length of the main machine stator core in an axial direction. 3 . The electric machine assembly of claim 2 , wherein the coolant inlet housing defines a first through-passage sized and configured to receive the stator winding through the second end of the first through-passage. 4 . The electric machine assembly of claim 3 , wherein the coolant outlet housing defines a second through-passage sized and configured to receive the stator winding through the first end of the second through-passage. 5 . The motor assembly of claim 3 , wherein a second end of the stator winding extends beyond the first through passage and is connected to an electrical terminal.

6. The electric machine assembly according to any one of claims 1 to 5, wherein at least one of the coolant inlet housing or the coolant outlet housing is in the form of a flat coolant housing.

7. An electric machine assembly according to any one of claims 1 to 5, wherein at least one of the coolant inlet housing or the coolant outlet housing is in the form of an annular coolant housing.

8. The motor assembly of any one of claims 1 to 5, wherein the motor assembly is a dry cavity motor assembly.

9. An electric machine assembly according to any one of claims 1 to 5, wherein the set of stator windings has a generally quadrilateral cross-section.

10. The electric machine assembly of any one of claims 1 to 5, further comprising an electrically isolating material externally enclosing the set of stator windings.

11. An electric machine assembly according to any one of claims 1 to 5, wherein the set of stator windings defines at least two fluid channels per winding.

12. The motor assembly of any one of claims 1 to 5, wherein the diameter of the fluid channel is between 1.0 mm and 2.0 mm.

13. An electric machine assembly according to any one of claims 1 to 5, wherein the coolant inlet passage, the fluid passage of the stator windings and the coolant outlet passage define a coolant circuit configured to receive a supply of coolant to remove heat generated in a set of stator windings.

14. A method of cooling a set of stator windings of an electric machine assembly, the method comprising: supplying a coolant flow to an inlet passage of a coolant inlet housing disposed at a common axial end of one side of a stator post of the electric machine assembly, the inlet passage being in fluid communication with a first end of a set of stator windings wound around the stator post and defining a closed fluid passage through the stator windings; conveying the coolant flow through the fluid passages of the stator windings; and The return of the coolant flow from the fluid passage is received at a second end of the set of stator windings at an outlet passage of a coolant outlet housing disposed at a common axial end on the other side of the stator post.

15. The method of claim 14, wherein supplying, delivering, and receiving the coolant flow are configured to remove heat generated in the set of stator windings.

16. The method of any one of claims 14 to 15, further comprising generating an electric current in the set of stator windings and supplying the generated electric current to a set of electrical terminals disposed at a common axial end of the stator poles.

17. The method of claim 16, wherein the set of electrical terminals is further disposed axially through at least one of the coolant inlet housing or the coolant outlet housing, opposite the stator post.

18. The method of any one of claims 14 to 15, wherein supplying the coolant flow comprises supplying the coolant flow to the coolant inlet housing in the form of an annular coolant housing or a flat coolant housing.

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