High-current density electrical machinery

Abstract

The electric machine includes a stator having a stator bore and a stator winding, the stator winding arranged to receive an electric current and generate an electric current having a power between 1 MW and 50 MW, the stator having a rated current of 5 A / mm 2 and a rotor is disposed at least partially within the stator bore and has a rotor winding, the rotor having a current density of 5 A / mm 2 Thus, the high pressure cooling system is operable to actively cool the stator and rotor, and the rotor windings and stator windings interact to either generate rotor rotation to drive a connected device in response to receiving electrical current, or generate electrical current in response to rotor rotation driven by a connected device.

Description

[Technical Field]

[0001] Electromechanical devices are used as generators, motors, or both, depending on the application. Large-scale industrial and marine electromechanical devices are often used as synchronous generators and / or motors, such as marine propulsion drive motors. Therefore, these electromechanical devices operate at numerous different speeds and various loads. [Background technology]

[0002] In one embodiment, the electromachine includes a stator having a stator bore and stator windings. The stator windings are arranged to receive current and generate a current having a power between 1 MW and 50 MW. The stator has a current of 5 A / mm 2 The stator current density is as described above. The rotor is at least partially located within the stator bore and has rotor windings. The rotor current density is 5 A / mm². 2 That concludes the explanation. The high-pressure cooling system is capable of operating to actively cool the stator and rotor. The rotor windings and stator windings interact with one of the generatings of the rotor's rotation, driving connected devices in response to the reception of current, and generating current in response to the rotation of the rotor driven by the connected devices.

[0003] In another configuration, the electromachine includes a stator having a stator bore and stator windings, a rotor at least partially located within the stator bore and having rotor windings, and a first cooling circuit operable to cool the stator windings with a first flow of high-pressure fluid. A second cooling circuit operable to cool the rotor windings with a second flow of high-pressure fluid, and the first and second cooling circuits constitute a closed system.

[0004] In another configuration, the electromachine includes a stator having a stator bore and stator windings. The stator housing is arranged to surround the stator and includes a first wall supporting a first bearing and a second wall supporting a second bearing. The rotor is at least partially located within the stator bore and has rotor windings. The rotor is rotatably supported by a first bearing and a second bearing. An excitation system is coupled to the rotor and located within the stator housing between the first and second bearings. The excitation system is operable to supply excitation current to the rotor windings. A high-pressure cooling system is operable to supply a first flow of high-pressure fluid to cool either the stator windings or the rotor windings. [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] Before describing embodiments of the present invention in detail, it should be understood that the present invention is not limited in its application to the structural details and arrangement of components described herein or illustrated in the following drawings. Other embodiments of the present invention are possible and can be carried out or implemented in various ways. Furthermore, it should be understood that the expressions and terms used herein are for illustrative purposes only and should not be considered limiting.

[0006] Next, various technologies relating to the system and method will be described with reference to the drawings, where similar reference numerals represent similar elements throughout. The drawings and various embodiments used in this patent document to illustrate the principles of the disclosure are for illustrative purposes only and should not be construed as limiting the scope of the disclosure. Those skilled in the art will understand that the principles of the disclosure can be implemented in any appropriately arranged apparatus. It should be understood that a function described as being performed by a particular system element may be performed by multiple elements. Similarly, for example, an element may be configured to perform a function described as being performed by multiple elements. Numerous innovative teachings of this application will be described with reference to exemplary, non-limiting embodiments.

[0007] Furthermore, it should be understood that the terms used herein should be interpreted broadly unless explicitly limited in some examples. For example, the terms “including,” “having,” and “comprising,” as well as their derivatives, mean inclusive without limitation. The singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise. In addition, the terms “and / or” as used herein refer to and encompass any possible combination of one or more of the enumerated items relating to them. The term “or” is inclusive and means “and / or” unless the context clearly indicates otherwise. Furthermore, while multiple embodiments or structures may be described herein, any features, methods, steps, components, etc. described in relation to one embodiment shall apply equally to other embodiments unless otherwise specifically stated.

[0008] Furthermore, while terms such as “first,” “second,” and “third” may be used in this specification to refer to various elements, information, functions, or actions, these elements, information, functions, or actions should not be limited by these terms. Rather, these numerical adjectives are used to distinguish different elements, information, functions, or actions from one another. For example, a first element, information, function, or action may be referred to as a second element, information, function, or action, and similarly, a second element, information, function, or action may be referred to as a first element, information, function, or action without departing from the scope of this disclosure.

[0009] Furthermore, the term “adjacent” can mean that an element is relatively close to another element but not in contact with it, or that an element is in contact with another part, unless the context clearly indicates otherwise. Additionally, the expression “based on” is intended to mean “at least partially based on” unless explicitly stated otherwise. Terms such as “approximately” or “substantially” are intended to cover variations in values ​​that fall within the normal industry manufacturing tolerances for that dimension. In the absence of industry standards, the following variations exist:

[0010] To facilitate the identification of discussions concerning specific elements or actions, the most significant digit or number in a reference number refers to the figure number in which that element first appears. [Brief explanation of the drawing]

[0011] [Figure 1] Figure 1 is a cross-sectional view of a generator, taken along its centerline, axis of rotation, or longitudinal axis. [Figure 2] Figure 2 is a perspective view of a rotor suitable for use in the generator shown in Figure 1. [Figure 3] Figure 3 is a perspective view showing a portion of a stator suitable for use in the generator shown in Figure 1. [Figure 4] Figure 4 is a perspective view of a rotor suitable for use in the generator shown in Figure 1. [Figure 5]FIG. 5 is a perspective cross-sectional view of a rotor including a pressurized rotor cooling system suitable for use in the generator of FIG. 1. [Figure 6] FIG. 6 is an axial end view of a portion of the rotor slots of the rotor of FIG. 5. [Figure 7] FIG. 7 is a schematic cross-sectional view of a portion of the slot of FIG. 6 and the rotor of FIG. 5. [Figure 8] FIG. 8 is a perspective partial broken-away perspective view of a portion of the axial end of the slot of the rotor of FIG. 5 showing a first ring seal area. [Figure 9] FIG. 9 is a perspective partial broken-away view of a portion of another axial end of the slot of the rotor of FIG. 5 showing another first ring seal area. [[ID=​​​​​​​​​​​​​​​​​​​​​​​​​​​Figure 19 is a cross-sectional view of a pump arrangement used for cooling an electric machine. [Figure 20] Figure 20 is a cross-sectional view of another pump arrangement used for cooling an electric machine. [Figure 21] Figure 21 is a schematic cross-sectional view of a low-speed electric machine.

Best Mode for Carrying Out the Invention

[0012] As shown in FIG. 1, the generator 100 includes a stator 300 and a rotor 200 supported to rotate within the stator 300. The stator 300 includes a stator housing 102 that surrounds and substantially encloses the stator core 104. The stator core 104 is often composed of a number of laminations 116 laminated longitudinally (along the axis of rotation). Each lamination 116 is shaped to define the desired characteristics of the rotor body 120, including cutouts or, alternatively, a bore 118 sized to receive the rotor 200.

[0013] In some configurations, a stator cooling system 106 is provided to cool the stator 300 and improve the efficiency and current density of the stator 300. In some configurations, a cooling gas is employed as the stator coolant. However, the stator 300 can include liquid cooling, such as water cooling, if desired.

[0014] The rotor 200 includes a rotor body 120, a rotor shaft 122, and two retaining rings 114 coupled to the rotor shaft 122. In many embodiments, the rotor body 120 is considered part of the rotor shaft 122. The illustrated rotor shaft 122 is rotatably supported by bearings 110 located at both ends of the rotor 200. A turbine coupling 108 is located at one end of the rotor 200 and facilitates connection of the rotor 200 to a turbine (e.g., a combustion turbine, steam turbine, hydraulic turbine, wind turbine, etc.) or to other prime movers when operating as a generator. When operating as a motor, the turbine coupling 108 can also be connected to power output devices such as propellers, compressors, and gearboxes. The opposite end of the rotor 200 may include an excitation system coupling 112 that allows connection to an excitation system or other rotating equipment.

[0015] The generator 100 shown in Figure 1 is a synchronous generator. However, asynchronous generators or motors, etc., may also include the features described herein.

[0016] Figure 2 illustrates the rotor 200 of Figure 1 in more detail. The rotor body 120 includes a series of rotor slots 202 extending longitudinally along the rotor body 120. The rotor windings 204 are arranged within the rotor slots 202 and define one or more pairs of poles. In the illustrated structure, the rotor windings 204 form two poles. However, other structures may include four, eight, or more poles as needed. The rotor 200 also includes conductors 206, sometimes referred to as the magnetic field, which are connected to an excitation system that generates a magnetic field by supplying current at a desired voltage to the rotor windings 204. A suitable excitation system may include, but is not limited to, an exciter, a current collector, and a rotary transformer.

[0017] The rotor 200 may also include a rotor cooling system 208 that operates to cool the rotor 200. Depending on the design, the rotor 200 may be air-cooled, but other designs may use a different fluid, such as hydrogen.

[0018] Returning to Figure 3, the stator core 104 is illustrated in more detail. In most structures, the stator core 104 is formed from a series of laminates 116 stacked longitudinally. Each laminate 116 includes cutouts, openings, or features that define the desired characteristics of the stator core 104 when stacked. Each laminate 116 includes a number of teeth 302 that are equally spaced circumferentially around a bore 118. The teeth 302 cooperate to define a series of slots extending longitudinally in the stator core 104. Bars 306 are placed within the slots and electrically connected to each other to define a series of stator windings. In the illustrated generator 100, the stator windings are arranged to define three phases. Generally, the three phases are electrically arranged to define a delta circuit, or a Y circuit as desired. Of course, other structures may include single phases, or more than three phases (i.e., six phases) as needed.

[0019] As part of the stator cooling system 106, each of the bars 306 may include one or more coolant passages 310 that allow coolant to flow along the length of the bar 306. As described, a coolant fluid such as water is often used to cool the stator 300.

[0020] Figure 4 better shows the rotor 200 of Figure 2 with one of the retaining rings 114 removed. The rotor 200 is a two-pole rotor having a single rotor winding 204 shown in place. The rotor 200 includes a rotor shaft 122 supporting a plurality of teeth 302 extending radially outward around the outer circumference of the rotor shaft 122. In most constructions, the teeth 402 are machined from a solid shaft such that the teeth 402 and the rotor shaft 122 form an inseparable part. Each tooth 402 cooperates with an adjacent tooth 402 to define one of the rotor slots 202 between them.

[0021] Each tooth 402 defines the outermost surface that defines the maximum diameter of the rotor shaft 122. The retaining ring fitting portion 404 may be machined on the teeth 402 near its axial end to provide a fitting position for the retaining ring 114. Of course, the retaining ring fitting portion 404 may be omitted in other structures, or several different arrangements of the retaining ring fitting portion 404 may be included.

[0022] The rotor winding 204 is formed from a series of coils defining a continuous or complete loop. Thus, each coil extends in a first axial direction along a first rotor slot 202, forming a loop at a first end to define an end turn 406, and then extends in a second axial direction in the second rotor slot 202 in the opposite direction to the first, forming a second turn to complete the loop. A series of coils are stacked and connected to one another to define various rotor windings 204, which work together to define the desired poles.

[0023] A layer of insulator 408 is placed between adjacent coils within each rotor slot 202 to insulate them from each other in order to reduce the possibility of undesirable connections between the coils. One or more wedges 410 are placed on the outer diameter or top of each rotor slot 202 to wedge the coils and insulators and to prevent undesirable movement during operation. The retaining rings 114 are then coupled to the rotor shaft 122 such that each retaining ring 114 engages with one of the retaining ring fittings 404, so that the retaining rings 114 can cover and protect the end turns 406 while holding the end turns 406 in place.

[0024] Figure 5 shows a rotor 500 suitable for use with the generator 100 of Figure 1. The rotor 500 includes a rotor cooling system 520 that allows for the circulation of a pressurized coolant, typically air, through the rotor body 120 to cool the rotor body 120, more specifically the rotor windings 204, and to provide more efficient operation at both higher current densities and higher power densities than can be achieved by other means.

[0025] The rotor cooling system 520 is a closed system that can receive compressed air from a stationary compressor (not shown) so that the air (or other gas, if used) in the system is maintained at a desired high pressure (i.e., higher than atmospheric pressure). The rotor cooling system 520 includes a coolant pump 502, an inlet bore 504, an outlet annular section 506, one or more inlet openings 516, a first coolant space 512, and a second coolant space 508. The coolant pump 502 in the illustrated structure includes a centrifugal pump or other mechanism that is directly connected to rotate co-rotating with the rotor shaft 122 and can circulate already pressurized air or other gas through the rotor cooling system 520. Alternatively, an external pump or compressor may be incorporated into the stationary section of the rotor cooling system to circulate the coolant. The coolant pump 502 is positioned to exhaust warm air cooled by a heat exchanger (not shown) and return it to the inlet bore 504 as part of the closed-loop high-pressure rotor cooling system 520, but other configurations are possible.

[0026] The inlet bore 504 extends along the entire length of the rotor 500 and includes a plug 518 positioned at one end to seal the inlet bore 504, thereby facilitating the containment of high-pressure coolant into it. One or more inlet openings 516 extend through the rotor shaft 122, providing a fluid connection between the inlet bore 504 and the first coolant space 512. In the illustrated structure, multiple inlet openings 516 extend radially through the rotor shaft 122. The number of inlet openings 516 and the size of those inlet openings 516 are selected to ensure a desired flow rate between the inlet bore 504 and the first coolant space 512.

[0027] The first coolant space 512 includes a pair of end turns 406 and is defined by the cooperation of the rotor shaft 122, the rotor body 120, one of the retaining rings 114, and the end plate 514. The first end of the retaining ring 114 cooperates with the rotor body 120 to define the first ring seal area 510. The second opposite end of the retaining ring 114 engages with the outer diameter of the end plate 514. The inner diameter of the end plate 514 engages with the rotor shaft 122 and seals the first coolant space 512. Although the end plate 514 is described as a single part, it should be noted that multiple parts or components may cooperate to define the end plate 514.

[0028] The first coolant space 512 is fluidly connected to the rotor slot 202 to facilitate the flow of high-pressure coolant from the first coolant space 512 to the second coolant space 508. The second coolant space 508 includes a second end turn 406 opposite the first end turn 406. The second coolant space 508 is substantially the same as the first coolant space 512 and is defined by the cooperation of the rotor shaft 122, the rotor body 120, the other retaining ring 114, and another end plate 514. The second coolant space 508 collects high-pressure coolant from the rotor slot 202 and directs its flow to the discharge annular section 506.

[0029] The discharge annular section 506 is formed by the cooperation of the rotor bore and the annular sleeve 522, which is located inside the rotor bore and spaced apart from the outer wall of the rotor bore. Therefore, the annular sleeve 522 divides the rotor bore into an inlet bore 504 inside the rotor annular sleeve 522 and the discharge annular section 506 formed by the cooperation of the rotor bore and the annular sleeve 522.

[0030] Figure 6 illustrates one apex or outer diameter portion of the rotor slot 202, which better illustrates the arrangement of the wedge 410. In the illustrated structure, each tooth 602 defines a tooth hook 604 that extends at an oblique angle with respect to the radial axis of the rotor 200.

[0031] Each wedge 410 includes two wedge hooks 606 and two seal slots 610. Each wedge hook 606 includes an oblique surface positioned to engage with one of the tooth hooks 604. Each seal slot 610 includes a rectangular cross-section groove extending along the wedge 410 in a direction substantially parallel to the longitudinal axis of the rotor 200. The illustrated structure includes rectangular seal slots 610, but other shapes may be used as desired. The seal slots 610 may be part of the wedge extrusion or machined into the wedge 410 after extrusion, as desired.

[0032] The sealing member 608 (or other sealing member) is positioned within the sealing slot 610 and is sized to form a fluid-tight seal between the teeth 602 defining the rotor slot 202 and the wedge 410 positioned within the rotor slot 202. In the illustrated structure, the sealing member 608 has a D-shaped cross-section. Of course, other shapes (e.g., O-shaped cross-section) or other sealing members can be used as desired.

[0033] In the illustrated structure, the wedge 410 and sealing member 608 extend along the entire length of the rotor slot 202 to reduce the possibility of leakage. In addition, in the illustrated structure, each side of the wedge 410 supports a separate sealing member 608. However, in other structures, a sealing member 608 in the form of a continuous loop may also be used if necessary.

[0034] One suitable sealing member 608 for use in the structure of Figure 6 includes an elastic material formed in a "D" shape (i.e., a D-shaped cross-section), but is a single member with two separate ends rather than being formed in a loop. Furthermore, some structures include an adhesive portion 614 or material on the flat side of the D-shaped cross-section. The adhesive portion 614 attaches the sealing member 608 to the wedge 410, reducing the possibility of the sealing member 608 moving relative to or stretching undesirably during the installation of the wedge 410. Two separate sealing members 608 are used, one positioned on each side of the wedge 410. Suitable elastic materials include rubber, synthetic rubber, or other suitable materials.

[0035] Figure 7 shows in more detail the ring seal region 510 located adjacent to the first coolant space 512. However, it should be understood that the illustrated ring seal region 510 can also be located adjacent to the second coolant space 508.

[0036] The ring seal region 510 includes two separate seals formed between the retaining ring 114 and the rotor body 120. The shrink-fit seal 706 is formed between the retaining ring 114 and the rotor body 120 when the retaining ring is positioned in its working position with a proper shrink fit. A ring seal 702 is positioned between the retaining ring 114 and the rotor body 120, forming another circumferential seal. The ring seal 702 defines an inner diameter that coincides with the position of the sealing member 608, so that the ring seal 702 also cooperates with the sealing member 608 to complete the sealing of the first coolant space 512. The pressure 704 applied by the high-pressure coolant is completely contained, as the only path from the first coolant space 512 is through the rotor slots 202 and rotor windings 204 contained therein. In the illustrated structure, the ring seal 702 is a continuous circular sealing member having an O-shaped cross-section. Of course, other shapes (e.g., D-shaped cross-sections) and arrangements can also be employed. A typical ring seal 702 is formed from an elastic material (e.g., rubber), but other structures can employ more rigid materials, composite seals, spring-based seals, etc. Thus, the ring seal 702 should not be limited to the arrangement shown in Figure 7.

[0037] Figure 8 shows another arrangement of the ring seal area 510 suitable for use with one or both of the retaining rings 114 (not shown in Figure 8). The arrangement in Figure 8 forms at least partially the same shrink-fit seal between the retaining ring 114 and the rotor body 120, more specifically between the rotor teeth 402 and the wedge 810, as described with respect to Figure 7.

[0038] The structure in Figure 8 includes a ring seal 808, which is a composite of an elastic member 802 and a sleeve 804. The elastic member 802 may include a solid continuous member having an O-shaped cross-section, or it may be formed from other more rigid or composite materials, as described with respect to the ring seal 702 in Figure 7. In another structure, the elastic member 802 includes a spring-biased seal formed from a coil-like material similar to a coil spring (e.g., an inclined coil spring, a helical spring, etc.). Thus, in this structure, the elastic member 802 has an annular cross-section.

[0039] The sleeve 804 is formed to have a U-shaped cross-section that defines a receiving space in which the elastic member 802 is positioned. The sleeve 804 covers and protects the elastic member 802 during operation and makes direct contact with the rotor body 120, the wedge 810, and the retaining ring 114 when the retaining ring 114 is in its operating position. It should also be noted that the open end of the U-shaped cross-section is positioned to face the direction in which the high-pressure fluid is positioned (i.e., the direction of the first coolant space 512 and the second coolant space 508). In this configuration, when the sleeve 804 is exposed to the high-pressure fluid, the U-shaped cross-section tends to expand, thereby increasing the sealing effect of the ring seal 808.

[0040] Unlike the structure in Figure 7, the ring seal 808 includes an inner diameter portion positioned radially outward from the sealing member 608. Rather than cooperating with the sealing member 608 to form a seal, the ring seal 808 is positioned to pass through the intersection of the tooth hook 604 and the wedge hook 606. In this position as well, the same effective seal is formed. Of course, the ring seal 808 can also be positioned radially inward from the illustrated position to contact the sealing member 608 as needed, forming a seal very similar to that described with respect to Figure 7.

[0041] The retaining ring key 806 is positioned in a slot formed in the rotor body 120 and the wedge 810, and works in cooperation with the retaining ring 114 to maintain the retaining ring 114 in its desired operating position.

[0042] Figure 9 shows a structure similar to that of Figure 8, except for the positioning of the ring seal 808. In the structure of Figure 9, the inner diameter of the ring seal 808 is aligned with the sealing member 608 so that the ring seal 808 and the sealing member 608 cooperate to define at least a portion of the seal between the retaining ring 114, the rotor body 120, and the wedge 810.

[0043] Figure 10 shows an alternative structure of wedge 1008 suitable for use in place of or with wedges 410 and 810. Wedge 1008 includes a wedge body 1010, a wedge insert 1002, a wedge cap 1004, and one or more wedge bolts 1006. The wedge body 1010 is similar to that of wedge 810, but is shorter so that the remaining components, positioned at either end, complete wedge 1008 and make wedge 1008 the same length as wedge 810. Figure 10 shows one end of wedge 1008, but it should be understood that the same or similar arrangement can be formed at either end. For this reason, only one end will be described in detail.

[0044] The wedge insert 1002 is positioned to be substantially in contact with the end of the wedge body 1010 and may have the same or similar cross-sectional shape as the wedge body 1010. The wedge insert 1002 is formed from an elastic material that expands radially and circumferentially in response to axial compression. The material used is selected to provide the desired expansion, as will be described in more detail. The wedge cap 1004 forms a seal by the Poisson effect. However, another type of wedge insert based on geometric interference also works. In this configuration, the wedge insert has a tapered shape with a thin outer wall that can be pressed axially. This thin outer wall, if a sufficiently suitable material is used, flexes and provides sufficient contact pressure to seal.

[0045] The wedge cap 1004 is positioned to contact the wedge insert 1002 such that the wedge insert 1002 is sandwiched between the wedge cap 1004 and the wedge body 1010. The wedge cap 1004 has the same or similar cross-sectional shape as the wedge body 1010 and is generally formed from similar materials. The wedge bolt 1006 passes through the wedge cap 1004 and the wedge insert 1002 and engages with the wedge body 1010 in a screwable manner. When the wedge bolt 1006 is tightened, the wedge insert 1002 is compressed and expands or bulges radially and circumferentially. This expansion enhances the contact between the wedge insert 1002 and the adjacent part, forming a more effective seal between them.

[0046] The remaining structure of the ring seal region 510 in Figure 10 is the same as that in Figure 8. The ring seal 808 is positioned such that its inner diameter matches or is near the outer diameter of the wedge insert 1002. The structure of the ring seal 808 is otherwise the same as that described with respect to Figures 8 and 9. The retaining ring key 806 is also formed and positioned in the same manner as described with respect to Figures 8 and 9.

[0047] The wedge 1008 includes two sealing members 608 as described above. The sealing members 608 can engage with the wedge body 1010, the wedge insert 1002, and the wedge cap 1004, respectively, in substantially the same manner as described above. Furthermore, the ring seal 808 is positioned on the outer diameter of the sealing members 608, as described with respect to the structure in Figure 8.

[0048] It should be noted that the features described above can be combined to define different arrangements of the ring seal region 510. Therefore, the arrangements should not be limited to the examples provided herein.

[0049] Figure 11 shows an example of a combination of the different elements described above cooperating to define the ring seal area 510. In the illustrated structure, the wedge 1102 includes a wedge body 1104, a wedge insert 1002, a wedge cap 1004, and one or more wedge bolts 1006. The wedge body 1104 includes a receptacle for receiving the wedge insert 1002 such that the inner diameter of the wedge insert 1002 is positioned adjacent to or in contact with the wedge body 1104. Furthermore, the plane of the wedge insert 1002 is in contact with the plane of the wedge body 1104. The wedge cap 1004 is positioned in the same manner as described for the wedge insert 1002, except that the wedge cap 1004 is in contact with the wedge insert 1002. Thus, the wedge insert 1002 is sandwiched between the wedge cap 1004 and the wedge body 1104. As described with respect to the structure in Figure 10, the wedge insert 1002 and wedge cap 1004 may have the same or similar cross-sectional shape as the wedge body 1104. The wedge bolt 1006 passes through the wedge cap 1004 and the wedge insert 1002 and engages threadlessly with the wedge body 1104, compressing the wedge insert 1002 and causing the desired radial and circumferential expansion. In this structure, the wedge insert 1002 directly contacts the retaining ring 114 and the wedge body 1104 to form a first seal.

[0050] The ring seal 702 is positioned axially away from the rotor body 120, between the wedge body 1104 and the retaining ring 114. The illustrated ring seal 702 is the same as the ring seal 702 described with respect to Figure 7, and a detailed description is omitted. Of course, the ring seal 702 can be replaced with a ring seal similar to or identical to the ring seal 808 described with respect to Figure 8, if desired.

[0051] Similar to the arrangements in Figures 7 to 10, the retaining ring key 806 is positioned at the end closest to the rotor body 120 and operates in much the same manner as the retaining ring key described earlier. Finally, the arrangement in Figure 11 includes three different shrink fit positions 1106 that operate to further enhance the seal of the ring seal area 510.

[0052] Figure 12 shows an electromachine 1200 including a stator 1202, a rotor 500, and a stator housing 1204 positioned to surround and enclose at least a portion of the stator 1202 and rotor 500. The electromachine 1200 shown in Figure 12 may include a generator, a motor, or a machine capable of operating as either a generator or a motor. Furthermore, the electromachine 1200 may be synchronous or asynchronous and may operate at high speed (e.g., 10,000 RPM), low speed (e.g., 100 RPM), and any speed in between. Thus, the terms electromachine, generator, and motor are all applicable to the components illustrated herein.

[0053] The rotor 500 may be one of the rotors described with respect to Figures 1 to 11, or may include variations of those rotors. The stator 1202 defines a stator bore 1220 that receives the rotor 500. During operation, the electromachine 1200 can generate electricity (i.e., act as a generator) or use electricity (i.e., act as a motor). Some electromachines 1200 may act as either a generator or a motor, as may be required for certain modes of operation.

[0054] The stator housing 1204 includes a first wall supporting a first bearing 1206 and a second wall opposite the first wall supporting a second bearing 1208. In the illustrated structure, the stator housing 1204 includes two side walls extending between the first and second walls and a top covering the space defined by the side walls, the first wall, and the second wall. The first bearing 1206 and the second bearing 1208 cooperate to fully and rotatably support the rotor 500.

[0055] An excitation system 1210, such as an excitation device or alternative excitation device, can be positioned between the first bearing 1206 and the second bearing 1208, such that the excitation system 1210 is located within the stator housing 1204. Positioning the excitation system 1210 within the stator housing 1204 and between the bearings allows for a slight reduction in the rotor 500's length, while also providing further protection for the excitation system 1210 and, as will be described in more detail, the ability to cool the excitation system 1210 within the stator 1202.

[0056] The first heat exchanger 1212 and the second heat exchanger 1214 are located on the stator housing 1204 and are part of the cooling system of the electromechanical unit 1200. Any number of heat exchanger configurations are suitable for use as the first heat exchanger 1212 and / or the second heat exchanger 1214. For example, a closed air circuit air-cooled (CACA) configuration can be used for either or both of the first heat exchanger 1212 and / or the second heat exchanger 1214, as can a closed air circuit water-cooled (CACW) configuration. If desired, an air-to-water (CWA) configuration can also be used. It should be noted that in the descriptions of heat exchanger configurations, air is referred to as the cooling fluid. However, other gases (e.g., hydrogen, refrigerants, etc.) can be used if desired. Furthermore, where water is described as the coolant in the heat exchanger, other fluids or other cooling sources can be used if desired.

[0057] Figure 13 shows a portion of the stator 1202, including the stator core 1302 and stator windings 1304. The stator core 1302 may include multiple stacks arranged in a stacking direction to form a magnetic core. A series of structural members, such as tension rods and bolts, hold the stacks in the desired position. Each stack has a cross-sectional shape that defines the stator bore 1220 and an optional stator slot 1402 (illustrated in Figure 14). In some structures, the stacks or the stator core 1302 itself define a cooling gap that allows coolant to flow through the stator core 1302 in a direction substantially perpendicular to the central axis of the stator bore 1220. Of course, in other structures, a flow path can be provided that allows the coolant to flow parallel to the bore or in any other desired direction.

[0058] The stator winding 1304 includes a plurality of stator coils 1404 (shown in Figure 14) that are arranged within various stator slots 1402 and electrically connected to define a continuous stator winding 1304. The stator winding 1304 can be arranged in a Y-circuit or delta-circuit for a three-phase electric machine 1200, or in any other desired arrangement (e.g., a single-phase machine). One or more main lead wires 1306 extend through the stator housing 1204 to allow external electrical connections to the stator winding 1304.

[0059] Turning to Figure 14, one of the stator slots 1402 is shown to better illustrate the stator coil 1404 arranged therein. The stator coil 1404 can be arranged in any desired pattern, including the arrangement illustrated in Figure 14. Each of the stator coils 1404 has a substantially rectangular cross-section, where a coil channel 1406 is defined. The coil channel 1406 allows for the flow of coolant to directly cool the stator coil 1404, as will be described in more detail. The illustrated structure includes stator coils 1404 having a substantially rectangular cross-section and substantially rectangular coil channels 1406, but other shapes or arrangements can be adopted as desired.

[0060] To guide the coolant into the coil channel 1406, the stator 1202 includes an inlet manifold 1502 and a plurality of coolant tubes 1504 at one end of the stator 1202. As shown in Figure 15, the inlet manifold 1502 distributes the cold coolant to each of the coolant tubes 1504, which then guide the coolant to various stator coils 1404. The coolant flows through the coil channel 1406 to the other side of the stator 1202, where a second set of coolant tubes 1504 collects the coolant and guides it to an outlet manifold 1602 (shown in Figure 16) for collection.

[0061] Figure 16 better illustrates the flow path of the coolant outside the stator coil 1404. As described with respect to Figure 15, the inlet manifold 1502 receives the cold coolant for distribution to the stator coil 1404. After passing through the stator coil 1404, the coolant is collected in the outlet manifold 1602. The outlet manifold 1602 is similar to the inlet manifold 1502 in that it forms a partial arc to allow for easy collection or distribution to / from various stator coils 1404. Of course, other shapes or arrangements can also be employed.

[0062] After accumulating in the outlet manifold 1602, the hot coolant flows through one or more transfer pipes 1604 to the return flange 1606. In the illustrated structure, the transfer pipes 1604 pass through the stator housing 1204, and the return flange 1606 is located outside the stator housing 1204. However, in other configurations, the return flange 1606 may also be located inside the stator housing 1204.

[0063] One or more exhaust pipes 1608 extend between a first end and a second end of the stator core 1302. Each exhaust pipe 1608 is a roughly cylindrical tube sized to allow cooling gas to pass from one end of the stator core 1302 to the other end of the stator core 1302 without directly cooling the stator core 1302.

[0064] Figures 17 and 18 show together the cooling system of the electromechanical unit 1200, including a high-pressure cooling system 1700 and a low-pressure cooling circuit 1800. The high-pressure cooling system 1700 is positioned to directly cool the stator coils 1404, which constitute the stator windings 1304 and rotor windings 204. Specifically, a first cooling circuit 1702 is provided for cooling the stator coils 1404, and a second cooling circuit 1704 is provided for cooling the rotor windings 204. Before proceeding, it should be noted that the term “high pressure” as used herein with respect to the cooling system refers to the gauge pressure within the high-pressure cooling system 1700 sufficient to move a cooling fluid, typically air, through the high-pressure cooling system 1700 at the desired flow rate. In most configurations, the desired flow rates of the first cooling circuit 1702 and the second cooling circuit 1704 are independent of each other and are selected to achieve the cooling required for the application. The actual pressure in the first cooling circuit 1702 and the second cooling circuit 1704 is preferably higher than atmospheric pressure (e.g., 2 to 20 bar) so that the system is pressurized. However, the pump assembly 1218, or an alternative external pump, operates to slightly increase the pressure to achieve the desired flow rate. The actual pressure in the first cooling circuit 1702 and the second cooling circuit 1704 is controlled by an external pressure source, such as an instrument air source, an external compressor, or a supply of high-pressure gas.

[0065] Referring to Figure 17, the first cooling circuit 1702 begins at the pump assembly 1218, where the flow of cooling gas, in this configuration air, is led to the first heat exchanger 1212, where the cooling gas is cooled. As previously mentioned, the first heat exchanger 1212 can use a number of different cooling sources, including air-to-air, water, or another liquid. Once cooled, the now cold cooling gas exits the first heat exchanger 1212 and flows into the inlet manifold 1502. The inlet manifold 1502 distributes the cooling gas to the stator coil 1404 via the coolant tube 1504. The cooling gas flows along the length of the stator coil 1404, cooling the stator coil 1404. The heated cooling gas exits the stator winding 1304 at the opposite end of the stator 1202 via the second coolant tube 1504. The hot cooling gas is collected in an outlet manifold 1602 and directed to the opposite end of the electromachine 1200 using one or more transfer pipes 1604. The transfer pipes 1604 lead to a return flange 1606 that connects to the pump assembly 1218 to return the hot cooling gas to the pump assembly 1218. The pump assembly 1218 operates to increase the pressure of the cooling air to maintain a desired flow rate through the first cooling circuit 1702, as will be described in more detail.

[0066] The portion of the second cooling circuit 1704 passing through the rotor 500 has been described in detail with respect to Figures 1 to 11. The second cooling circuit 1704 begins at the pump assembly 1218, where a flow of high-temperature cooling gas, in this example air, is led to the first heat exchanger 1212 for cooling. The illustrated first heat exchanger 1212 is a cooling circuit that can contain three circuits, one of which contains the cooling air for the first cooling circuit 1702, and another which contains the cooling air for the second cooling circuit 1704, and operates to cool the cooling air in the other two circuits. In this way, the first heat exchanger 1212 cools two separate flows of cooling air without mixing the air. Of course, in other configurations, separate heat exchangers may be included, or the flows for cooling may be combined within the first heat exchanger 1212 and separated before entering the electromechanical unit 1200, so that the first heat exchanger 1212 contains only two circuits.

[0067] After exiting the first heat exchanger 1212, the now cooled cooling gas in the second cooling circuit 1704 is led to the rotor inlet bore 504. The cooling gas flows to the far end of the rotor 500, through the rotor core, specifically through the rotor windings 204 as described above, and cools the rotor windings 204. The hot cooling gas exits the rotor windings 204 and enters the discharge annular section 506 defined by the annular sleeve 522, returning to the pump assembly 1218. The pump assembly 1218 is pumped at least 5 A / mm 2 , compressive 6~10A / mm 2 The system operates to increase the pressure of the cooling air to maintain a desired flow rate through the second cooling circuit 1704 at a desired flow rate that is at least partially selected to achieve a desired current density between the two.

[0068] In a structure including a first heat exchanger 1212 having only two circuits (i.e., a cold circuit and a hot circuit), the hot cooling gas enters as a single flow, is cooled within the first heat exchanger 1212, and then exits the first heat exchanger 1212, splitting into two flows: one for the first cooling circuit 1702 and the other for the second cooling circuit 1704.

[0069] During operation, cooling gas (air) may leak from the first cooling circuit 1702 and / or the second cooling circuit 1704. Supplemental air may be supplied from gas supply 1706, which may include external gas storage, instrument air, or other sources of clean cooling gas.

[0070] Looking at Figure 18, the low-pressure cooling circuit 1800 is configured to supply additional cooling gas, in this example air, to cool the components of the electromechanical unit 1200 located within the stator housing 1204. The high-pressure cooling system 1700 is a closed system containing multiple sealed flow paths in one or more closed loops, whereas the low-pressure cooling circuit 1800 is an open system in which the cooling gas flows freely in a space that is not completely closed or sealed. The low-pressure cooling circuit 1800 begins with a fan 1216 rotating with the rotor 500. The fan 1216 is fixedly mounted to the rotor 500 and rotates with it to generate a flow of low-pressure cooling air, although an external fan may be a suitable alternative depending on the application. The low-pressure cooling air flows from the fan 1216 to a second heat exchanger 1214, where it is cooled in a similar manner to that described with respect to the first heat exchanger 1212. The second heat exchanger 1214 discharges the cooled low-pressure cooling air into the space containing the stator core 1302. A portion of the low-pressure cooling air flows through the stator core 1302, cooling it. A portion of this cooling air is discharged into the stator bore 1220, where it flows toward each end of the stator 1202. The low-pressure cooling air that does not pass through the stator core 1302 is led through one or more low-pressure cooling ducts 1802 leading to the excitation system space 1804 within the stator housing 1204. The low-pressure cooling air in the excitation system space 1804 provides cooling not only to the excitation system 1210 but also to other components that may be located within the excitation system space 1804 (e.g., permanent magnet generators (PMGs)). The low-pressure cooling air in the excitation system space 1804 flows back into the fan 1216 through one or more exhaust pipes 1608 formed within the stator housing 1204. Alternatively, the flow direction of this low-pressure cooling circuit can be reversed by reversing the direction in which the fan discharges (i.e., the fan direction).

[0071] Figure 19 shows a rotor-mounted pump assembly 1900 suitable for use as pump assembly 1218. The rotor-mounted pump assembly 1900 includes a pump housing 1902 enclosing a first pump impeller 1904 and a second pump impeller 1906. The illustrated first pump impeller 1904 and second pump impeller 1906 are closed centrifugal impellers, other types of impellers are also possible. The first pump impeller 1904 and second pump impeller 1906 are directly mounted to the rotor 500 in a back-to-back configuration and are designed to rotate with it. Of course, other configurations and mountings are possible if necessary.

[0072] A primary seal 1908 is coupled to the pump housing 1902, forming a seal between the stationary pump housing 1902 and the rotor 500. The primary seal 1908 includes a gas seal arrangement, but may include a number of different arrangements as needed to provide the desired sealing efficiency. A number of secondary seals 1910 are positioned between the pump housing 1902 and the rotor 500, the first pump impeller 1904, and the second pump impeller 1906 to establish the desired seal and independent flow paths.

[0073] As shown in Figure 19, the arrangement of the rotor-mounted pump assembly 1900 causes the rotation of the rotor 500 to rotate both the first pump impeller 1904 and the second pump impeller 1906. The first pump impeller 1904 draws in hot cooling gas (air) from the first cooling circuit 1702 into the first hot gas return space 1912. The first pump impeller 1904 compresses, pumps, or blows out the hot cooling gas from the rotor-mounted pump assembly 1900 via the first hot gas outlet 1916. The first hot gas outlet 1916 leads to the first heat exchanger 1212, where the hot cooling gas is cooled.

[0074] The second pump impeller 1906 draws in hot cooling gas (air) from the second cooling circuit 1704 into the second hot gas return space 1914. The second pump impeller 1906 compresses, pumps, or blows out the hot cooling gas from the rotor-mounted pump assembly 1900 via the second hot gas outlet 1918. The second hot gas outlet 1918 leads to the first heat exchanger 1212, where the hot cooling gas is cooled.

[0075] Figure 20 shows an external pump assembly 2000, which is also suitable for use as part of the pump assembly 1218. The external pump assembly 2000 includes a pump housing 1902 that surrounds a portion of the rotor 500. A primary seal 1908, similar to the primary seal 1908 in Figure 19, and a secondary seal 1910, similar to those described with respect to Figure 19, are provided to form a seal between the rotor 500 and the stationary pump housing 1902. The pump housing 1902 defines a second hot gas outlet 1918 that captures hot cooling gas from the second cooling circuit 1704 and directs it to the first heat exchanger 1212.

[0076] Instead of employing a shaft-mounted impeller as illustrated in Figure 19, the structure in Figure 20 includes an external pump 2002 (sometimes called a compressor or blower). The external pump 2002 receives the flow of cooled gas from the first heat exchanger 1212, increases the pressure or flow rate of the cooled gas, and directs it to the rotor inlet bore 504. Another external pump 2002 may also be provided to compress or pump the cooled gas within the first cooling circuit 1702. The external pump for the first cooling circuit 1702 is much simpler because the first cooling circuit 1702 includes components that do not move significantly relative to each other, and therefore does not require the formation of seals between stationary and rotating parts as required in the second cooling circuit 1704.

[0077] It should be noted that there are numerous possible variations in the arrangement of the pump assembly 1218 and the first heat exchanger 1212. For example, a rotor-mounted pump assembly 1900 could be used as the pump assembly 1218, or a fully externally driven system such as the external pump assembly 2000 shown in Figure 20 could be used. In other configurations, one of the first cooling circuit 1702 and the second cooling circuit 1704 includes a shaft-mounted pump, while the other of the first cooling circuit 1702 and the second cooling circuit 1704 includes an external pump. In addition, the pumps can be positioned at different locations within each cooling circuit, as desired, regardless of the configuration.

[0078] Furthermore, the first high-temperature gas outlet 1916 and the second high-temperature gas outlet 1918 may be coupled to a single flow that can be generated by one or more external pumps, one or more shaft-mounted impellers, or a combination thereof.

[0079] The first heat exchanger 1212 can also include several different configurations. In the configuration shown in Figure 17, the first heat exchanger 1212 includes a first internal circuit or loop for the cold fluid and two separate internal circuits or loops for the hot fluid. The first cooling circuit 1702 includes the first of the hot fluid loops in the first heat exchanger 1212, and the second cooling circuit 1704 includes the second of the hot fluid loops. Thus, in this configuration, the cooling fluids of the first cooling circuit 1702 and the second cooling circuit 1704 do not mix but are cooled by a common cold fluid circuit.

[0080] In an alternative configuration, the heat exchanger includes one low-temperature fluid loop and one high-temperature fluid loop. In this configuration, the first cooling circuit 1702 and the second cooling circuit 1704 are combined into a single flow before entering the first heat exchanger 1212. After passing through the first heat exchanger 1212, the single flow is again split into the first cooling circuit 1702 and the second cooling circuit 1704. In this configuration, controllable valves or orifices may be required to achieve the desired flow through the two cooling circuits.

[0081] In other configurations, two completely separate heat exchangers may be employed, each associated with either the first cooling circuit 1702 or the second cooling circuit 1704. Other arrangements of the pump and heat exchangers are also possible.

[0082] Figure 21 shows a low-speed electromachine 2100 that can be operated as a generator for generating electricity or as a motor for driving other devices such as propellers, compressors, pumps, etc. The low-speed electromachine 2100 has a high current density (i.e., 5 A / mm²). 2 Above or above, or 6-10 A / mm 2 It provides the above-mentioned power supply while including numerous features suitable for operation at rotational speeds below 1200 RPM.

[0083] The low-speed electromachine 2100 includes a stator housing 2102, a stator 2104, and a rotor 2106. The stator housing 2102 is positioned to house and protect the stator 2104 and defines a first space 2118 and a second space 2120.

[0084] The stator housing 2102 supports a first bearing 2116 and a second bearing 2108, which are arranged to rotatably support the rotor 2106. As discussed earlier, the rotor 2106 includes rotor windings 2110 that cooperate with stator windings 2124 to generate electricity when operated as a generator or to generate mechanical torque when operated as a motor. The excitation system 1210 (e.g., an exciter) is located within the stator housing 2102 between 2116 and 2108, as previously described.

[0085] The low-speed electromachine 2100 includes a cooling system that operates to cool the rotor 2106 and stator 2104, more specifically the rotor windings 2110 and stator housing 1204. The cooling system includes a fan 2112, a heat exchanger 2114, and a return path 2122. The fan 2112 is preferably positioned in the second space 2120 so as to draw air from the second space 2120 during operation and discharge that air into the heat exchanger 2114. Since the rotor 2106 operates at a low speed, it is not possible to effectively drive the fan 2112 directly. The fan 2112 may be driven by a generator if a gearbox or other device is employed to increase the speed and efficiency of the fan 2112. Alternatively, the fan 2112 may be driven electrically or mechanically by a separate motor.

[0086] The heat exchanger 2114 is located inside the stator housing 2102, but can alternatively be located outside the stator housing 2102. The heat exchanger 2114 receives the flow of cooling air from the fan 2112 and discharges the cooled cooling air into a return path 2122 that leads the air from the heat exchanger 2114 to the first space 2118.

[0087] During operation, cooling air in the first space 2118 flows through the rotor windings 2110 and stator windings 2124, providing cooling. The air then exits the rotor windings 2110 and stator windings 2124 and collects in the second space 2120. Fan 2112 operates to draw in the hot cooling air from the second space 2120 and direct it to the heat exchanger 2114. The heat exchanger 2114 receives a flow of cooling fluid that operates to cool the air supplied by fan 2112. The cooling fluid can be external air or another fluid such as water, which may be required to provide the desired cooling. In some configurations, a refrigeration system is provided to provide the desired cooling. The air cooled by the heat exchanger 2114 returns to the first space 2118 along the return path 2122 and starts the cycle again.

[0088] Although the return path 2122 is shown as being outside the stator housing 2102, it should be noted that, depending on the structure, the return path 2122 can be located entirely or partially inside the stator housing 2102.

[0089] During operation, the excitation system 1210 or other system supplies current to the rotor 200 at the desired voltage. The current flows through the rotor windings 204, establishing two poles in a two-pole generator / motor and more poles in a higher-pole generator / motor. The turbine, other prime mover, or driven component (e.g., propeller) is coupled to the rotor 200 and operates to rotate the rotor 200 at the desired speed or to be driven by the rotor 200. In the case of a synchronous electromachine 1200 with a two-pole rotor 200, the rotor rotates at 3600 RPM to generate electricity at 60 Hz. To generate electricity at 50 Hz, the rotor 200 rotates at 3000 RPM. Variations of this include constant-speed and variable-speed machines operating from 1 RPM to 20,000 RPM.

[0090] When the electromachine 1200 operates as a generator, the rotating magnetic field of the rotor 200 interacts with the generator's stator 300 to induce an alternating three-phase current at a frequency proportional to the rotor 200's speed. Cooling both the rotor 200 and the stator 300 increases the current density of both, while simultaneously maintaining the desired efficiency and maintenance interval.

[0091] The rotor 500 includes a rotor cooling system 520, 1704 and is initially assembled by positioning coils or rotor windings 204 into various rotor slots 202, or reassembled after maintenance. The rotor windings 204 are stacked to extend radially outward to substantially fill the rotor slots 202 and are electrically connected to define one of the poles of the rotor 500.

[0092] Since wedges 410, 810, 1008, and 1102 are substantially the same as each other, the assembly will be described in relation to wedge 1102. However, it will be clear that many of the steps are equally applicable to some or all of the other wedges 410, 810, 1008, and 1102.

[0093] The sealing member 608 is positioned on the side of various wedges 1102 (see Figure 6). As described, the sealing member 608 is D-shaped, and in some structures, the flat surface of the D shape contains an adhesive to facilitate attachment of the sealing member 608 to the wedge 1102.

[0094] The sealing members 608 are located radially inward of the wedge hooks 606 and are therefore inserted into each wedge 1102 before assembly into the rotor slots 202. This position of the sealing members 608 increases the likelihood that a sealing member 608 will be accommodated within the rotor slots 202 if one of the sealing members 608 deteriorates or fails. The position of the sealing members 608 away from the outer surface of the rotor 500 also helps to shield the sealing members 608 from large temperature fluctuations that may occur due to surface currents or other heating effects. The sealing members 608 also help to isolate the rotor windings 204 from the wedge hooks 606, shielding conductive wedge plating material that may loosen within the wedges from the rotor windings 204, thereby reducing the possibility of ground faults caused by this material.

[0095] Next, the wedges 1102 are attached to various rotor slots 202 to support the rotor windings 204 in the desired position during operation. The sealing member 608 is compressed against the wall of the rotor body 120 defining the rotor slots 202 to which each wedge 1102 is attached, thereby forming a primary seal for each rotor slot 202. The contact pressure between the wedge hook 606 and the tooth hook 604 of each rotor slot 202 also acts as a secondary seal to suppress unwanted leakage from the rotor slots 202. Thus, the attachment of the wedges 1102 provides an axially positioned seal to suppress leakage from the radially outward openings of the rotor slots 202. However, each end of the rotor slots 202 is still not sealed.

[0096] Wedge 1102 requires some additional assembly that may not be necessary for the other wedges 410, 810, and this assembly can be performed before or after mounting wedge 1102 to rotor 500, as desired. Each end of wedge 1102 receives a wedge insert 1002. Next, a wedge cap 1004 is positioned adjacent to each of the wedge inserts 1002. Each of the wedge bolts 1006 passes through the wedge cap 1004 and one of the wedge inserts 1002 and engages screwably with the wedge body 1104. Tightening the wedge bolts 1006 compresses the wedge insert 1002 axially and simultaneously expands it radially and circumferentially. The expansion of the wedge insert 1002 promotes cooperation between the wedge body 1104, the retaining ring 114 (after installation) or the ring seal 808, and the rotor teeth 402, further strengthening the seal between them. It should be noted that the wedge insert 1002 and the wedge cap 1004 can be attached to the wedge body 1104 without tightening the wedge bolt 1006. Then, after the wedge 1102 is in its operating position, the wedge bolt 1006 can be tightened to provide the desired compression of the wedge insert 1002.

[0097] Referring to Figure 10, the ring seals 808 are then positioned at both ends of the rotor 500. Both ring seals 808 are preferably continuous circular seals that extend around the circumference of the rotor 500 and engage with the rotor teeth 602, as well as the wedge 1102. The ring seals 808 are positioned radially outward of the wedge insert 1002 and can be positioned either before or after tightening the wedge bolts 1006. Generally, positioning the ring seals 808 in their desired operating position before tightening the wedge bolts 1006 will be easier because the ring seals 808 have a slightly loose fit before the wedge insert 1002 expands.

[0098] It should be noted that Figure 11 illustrates a slightly different position of the ring seal 702, and that it employs the ring seal 702 from Figure 7, rather than the ring seal 808 from Figure 8. It is important to note that the concepts described herein can be rearranged and used in different combinations to achieve the sealing required for a particular design. Thus, the sealing arrangements described should be considered only as examples and should not be considered limiting in any sense.

[0099] Next, the retaining ring 114 is installed as shown in Figures 10 and 11. In a typical installation, the retaining ring 114 is heated before installation to allow it to expand due to heat and provide a desired shrink fit at one or more shrink-fit positions 1106. Once installed, the retaining ring 114 works in cooperation with the rotor body 120, rotor shaft 122, and end plate 514 to define a first coolant space 512 and a second coolant space 508.

[0100] As shown in Figure 11, the retaining ring 114 works in cooperation with each wedge body 1104 to define three shrink-fit positions 1106 that form a seal. Furthermore, the ring seal 702 works in cooperation with the retaining ring 114 and the wedge body 1104 to define a primary seal. Finally, once expanded, the wedge insert 1002 provides yet another sealing point between the rotor 500 and the retaining ring 114, resulting in multiple effective sealing points that suppress leakage from the first coolant space 512 and the second coolant space 508.

[0101] Referring to Figure 5, the operation of the rotor cooling system 520 is described. While the rotor 500 is rotating, the coolant pumps 502, 1218 draw in warm air from the discharge annular section 506 and direct this air to the outside air cooler or heat exchanger 1212. The cooled air then flows along the inlet bore 504 to the inlet opening 516, where high-pressure air (generally greater than atmospheric pressure) enters the first coolant space 512. The first coolant space 512 is in fluid communication with each of the rotor slots 202 so that the high-pressure air can enter the rotor slots 202. The high-pressure air flows along the length of the rotor slots 202 to provide cooling and is collected in the second coolant space 508. The high-pressure air is directed from the second coolant space 508 to the discharge annular section 506, where it is drawn in by the coolant pumps 502, 1218 and discharged from the rotor 500. The seals described above reduce the possibility of leakage from the first coolant space 512, the second coolant space 508, and the rotor slot 202.

[0102] The proposed high-current-density electromachine uses a rotor 500 as a pressure vessel, pressurizing each rotor slot 202, a first coolant space 512, and a second coolant space 508. Wedges 410, 810, 1008, and 1102 include two conforming sealing members 608 that contact the side walls of the rotor slots 202. These sealing members 608 ensure airtightness of the rotor slots 202.

[0103] The pressurized lotus slots 202 enable direct cooling of the rotor winding 204 with high-pressure fluid without increasing frictional losses and without many complex electrical / fluid dual-purpose connections. Direct cooling with pressurized fluid enables mechanical operation with increased field current and ultimately enables a higher current density than previous air-cooled machines.

[0104] By using the high-pressure cooling system 1700 in combination with the low-pressure cooling circuit 1800 to cool the stator 1202, the stator 1202 can be made more compact and the current density of the electrical machine 1200 can be increased. Specifically, the electrical machine 1200 illustrated herein results in an electrical machine operating in the range of 1 MW to 50 MW with a current density exceeding 5 A / mm 2 and, in many configurations, operating between 6 A / mm 2 and 10 A / mm 2 and, in some configurations, providing an output density of at least 1.0 kW / kg at 3600 RPM.

[0105] The current density is measured at the minimum cross-sectional area of the conductors of the rotor winding and the stator winding. Thus, each of the rotor and the stator has a current density, and in most of the configurations described herein, those current densities are greater than 5 A / mm 2 and many are between 6 and 10 A / mm 2 inclusive.

[0106] Furthermore, by arranging the excitation system 1210 between the first bearing 1206 and the second bearing 1208, the cooling of the excitation system 1210 can be enhanced and the rotor 500 can be shortened. Also, by arranging the excitation system 1210 between the first bearing 1206 and the second bearing 1208, the pump assembly 1218 can be arranged closer to the first bearing 1206. This positioning reduces the vibration and runout of the pump assembly 1218 and thus enables a more effective seal between the pump housing 1902 and the rotor 500. <​​While exemplary embodiments of this disclosure have been described in detail, those skilled in the art will understand that various modifications, substitutions, variations, and improvements disclosed herein can be made without departing from the spirit and scope of the disclosure in its broadest form. In addition, any feature described in relation to one embodiment is equally applicable to other embodiments described herein.

[0108] Nothing in this specification should be read as implying that any particular element, step, act, or function is an essential element that must be included in the claims: the scope of the patent subject matter is defined solely by the permitted claims. Furthermore, these claims are not intended to evoke a means-plus-function claim structure unless the exact phrase “means for” is followed by a participle.

Claims

1. It is an electrical machine, A stator comprising a stator bore and stator windings, wherein the stator windings are arranged to receive current and generate a current having a power between 1 MW and 50 MW, and the stator has a current of 5 A / mm ２ Stator having a larger stator current density, A rotor having rotor windings, at least partially disposed within a stator bore, wherein the rotor has a winding capacity of 5 A / mm ２ A rotor having a larger rotor current density, and A high-pressure cooling system capable of operating to actively cool the stator and the rotor, wherein the rotor windings and the stator windings interact to rotate the rotor in response to the reception of the current to drive a connected device, or to generate the current in response to the rotation of the rotor driven by the connected device. Includes, The high-pressure cooling system comprises a first cooling circuit operable to cool the stator windings with a first flow of high-pressure fluid, and a second cooling circuit operable to cool the rotor windings with a second flow of high-pressure fluid, wherein the second cooling circuit is separate from the first cooling circuit.

2. The rotor current density and the stator current density are each 6 to 10 A / mm². ２ The electrical machine according to claim 1, characterized in that it is the same as the one described in claim 1.

3. The electric machine according to claim 1, further comprising a stator housing surrounding the stator, wherein the stator housing includes a first bearing and a second bearing, and the rotor is rotatably supported by the first bearing and the second bearing.

4. The electric machine according to claim 3, further comprising an excitation system operable to supply an excitation current to the rotor winding, wherein the excitation system is supported to rotate by the rotor and is located between the first bearing and the second bearing.

5. The electromachine according to claim 4, further comprising a low-pressure cooling circuit that includes a low-pressure airflow within the stator housing and is operable to at least partially cool the excitation system and the stator.

6. The electromachine according to claim 5, wherein the low-pressure cooling circuit includes a fan coupled to the rotor and capable of operating to generate the low-pressure airflow.

7. The electromachine according to claim 1, wherein the first cooling circuit includes a first heat exchanger operable to cool the first flow of high-pressure fluid and the second flow of high-pressure fluid.

8. The electromachine according to claim 1, wherein the first cooling circuit includes a first rotor-mounted pump operable to increase the pressure of the first flow of high-pressure fluid and a second rotor-mounted pump operable to increase the pressure of the second flow of high-pressure fluid.

9. The electromachine according to claim 1, wherein the second cooling circuit includes a first rotor-mounted pump operable to increase the pressure of the second flow of high-pressure fluid and an external pump separated from the rotor and operable to increase the pressure of the first flow of high-pressure fluid.

10. The electromachine according to claim 1, wherein the first cooling circuit includes a first external pump and a second external pump, each separated from the rotor, the first external pump being operable to increase the pressure of a first high-pressure fluid flow, and the second external pump being operable to increase the pressure of a second high-pressure fluid flow.

11. The electromachine according to claim 1, wherein each of the first cooling circuit and the second cooling circuit is a closed loop, and the first high-pressure fluid flow and the second high-pressure fluid flow include air.

12. It is an electrical machine, Stator including stator bore and stator windings, A rotor having rotor windings, which is at least partially disposed within the stator bore, A first cooling circuit capable of operating to cool the stator windings with a first flow of high-pressure fluid, And, A second cooling circuit capable of operating to cool the rotor windings with a second flow of high-pressure fluid, The first cooling circuit and the second cooling circuit constitute a closed system. The rotor further includes a stator housing surrounding the stator, the stator housing includes a first bearing and a second bearing, and the rotor is rotatably supported by the first bearing and the second bearing. The stator housing further includes a low-pressure airflow and a low-pressure cooling circuit that is operable to at least partially cool the excitation system and the stator. An electrical machine characterized by the following features.

13. The stator winding is arranged to receive current and generate a current having a power between 1 MW and 50 MW, and the rotor is 5 A / mm ２ Defining a higher rotor current density, the stator is 5 A / mm ２ The electromachine according to claim 12, which defines a larger stator current density.

14. The rotor current density and the stator current density are both 6 A / mm². ２ From 10 A / mm ２ The electrical machine according to claim 13, which is between [the specified range].

15. The electromachine according to claim 12, wherein the low-pressure cooling circuit includes a fan coupled to the rotor and capable of operating to generate the low-pressure airflow.

16. The electromachine according to claim 12, further comprising a first heat exchanger operable to cool the first flow of high-pressure fluid and the second flow of high-pressure fluid, and a second heat exchanger operable to cool the flow of low-pressure fluid.

17. An electrical machine, Stator including stator bore and stator windings, A rotor having rotor windings, which is at least partially disposed within the stator bore, A first cooling circuit capable of operating to cool the stator windings with a first flow of high-pressure fluid, And, A second cooling circuit capable of operating to cool the rotor windings with a second flow of high-pressure fluid, The first cooling circuit and the second cooling circuit constitute a closed system. The electromechanical device is characterized in that the first cooling circuit includes a first rotor-mounted pump operable to increase the pressure of the first flow of high-pressure fluid and a second rotor-mounted pump operable to increase the pressure of the second flow of high-pressure fluid.

18. An electrical machine, Stator including stator bore and stator windings, A rotor having rotor windings, which is at least partially disposed within the stator bore, A first cooling circuit capable of operating to cool the stator windings with a first flow of high-pressure fluid, And, A second cooling circuit capable of operating to cool the rotor windings with a second flow of high-pressure fluid, The first cooling circuit and the second cooling circuit constitute a closed system. The electromechanical device is characterized in that the first cooling circuit includes a first rotor-mounted pump operable to increase the pressure of the second flow of high-pressure fluid, and an external pump separated from the rotor and operable to increase the pressure of the first flow of high-pressure fluid.

19. The electromachine according to claim 12, wherein each of the first cooling circuit and the second cooling circuit is a closed loop, and the first flow of high-pressure fluid and the second flow of high-pressure fluid contain air.

20. It is an electrical machine, Stator including stator bore and stator winding, A stator housing is arranged to surround the stator and includes a first wall supporting a first bearing and a second wall supporting a second bearing. A rotor having rotor windings at least partially arranged within the stator bore, the rotor being rotatably supported by the first bearing and the second bearing, An excitation system coupled to the rotor and located within the stator housing between the first bearing and the second bearing, wherein the excitation system is operable to supply an excitation current to the rotor windings, and Includes a high-pressure cooling system that can be operated to supply a first flow of high-pressure fluid to cool one of the stator windings and the rotor windings, The high-pressure cooling system includes a first cooling circuit operable to cool the stator windings with a first flow of high-pressure fluid, and a second cooling circuit operable to cool the rotor windings with a second flow of high-pressure fluid, wherein the second cooling circuit is separate from the first cooling circuit. An electrical machine characterized by the following features.

21. The stator winding is arranged to receive a current and generate a current having a power between 1 MW and 50 MW, and the rotor defines a rotor current density greater than 5 A / mm ２ and the stator defines a stator current density greater than 5 A / mm ２ The electrical machine according to claim 20, wherein the electrical machine is defined as having a stator current density greater than 5 A / mm

22. The rotor current density and the stator current density are, respectively, 6 to 10 A / mm². ２ The electrical machine according to claim 21, characterized in that it is the same as the one described above.

23. The electromachine according to claim 20, further comprising a low-pressure cooling circuit that includes a low-pressure airflow within the stator housing and is operable to at least partially cool the excitation system and the stator.

24. The high-pressure cooling system includes a first heat exchanger operable to cool the first flow of a high-pressure fluid and a second heat exchanger operable to cool the low-pressure flow of air. The electrical machine according to claim 23.

25. The electromachine according to claim 20, wherein the first cooling circuit includes a first rotor-mounted pump operable to increase the pressure of the first flow of high-pressure fluid and a second rotor-mounted pump operable to increase the pressure of the second flow of high-pressure fluid.

26. The electromachine according to claim 20, wherein the first cooling circuit includes a first rotor-mounted pump operable to increase the pressure of the second flow of high-pressure fluid, and an external pump separated from the rotor and operable to increase the pressure of the first flow of high-pressure fluid.

27. The electromachine according to claim 20, wherein each of the first cooling circuit and the second cooling circuit is a closed loop, and the first flow of high-pressure fluid and the second flow of high-pressure fluid contain air.

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