Linear electromagnetic machine

Abstract

A linear electromagnetic machine includes a stator, a translator, and a bearing system. The bearing system remains aligned to resist lateral displacement of the translator relative to the stator when the translator is axially reciprocated. More particularly, the bearing system maintains a motor air gap between the stator and the magnet section of the translator. The stator includes a plurality of stator teeth and windings forming a plurality of phases. The stator teeth and windings are arranged using a stack of hoops with spines to form a stator bore and define a motor air gap. The bearing system may include a bearing housing configured to form a bearing interface that interfaces with a surface of the translator. The bearing interface may include a contact bearing or a non-contact bearing, such as a gas bearing. The current is controlled in the phase to convert between electrical and kinetic energy of the translator.

Description

[0001] This application is a divisional application of Chinese invention patent application No. 201980060703.4, which has entered the Chinese national phase of international application PCT / US2019 / 043321 with the invention name “Linear Electromagnetic Machine” and the international application date of July 24, 2019.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] The present disclosure relates to linear electromagnetic machines, and more particularly to linear electromagnetic machines having a translator, a stator, and a bearing. This application claims the benefit of U.S. Provisional Patent Application No. 62 / 702,860 filed on July 24, 2018 and U.S. Provisional Patent Application No. 62 / 703,338 filed on July 25, 2018, the disclosures of which are incorporated herein by reference in their entirety. Background Art

[0004] Linear motors convert between electrical energy and kinetic energy of moving elements. The design of linear motors must ensure efficient operation, cost-effective construction, and reliability. To match the efficiency of rotary generators, linear generators must be compatible with cheap and lightweight oscillator designs, employ efficient materials, allow geometry optimization, and provide high copper slot fill. The present disclosure addresses all four requirements. Summary of the invention

[0005] In some embodiments, the present disclosure relates to a linear electromagnetic machine (LEM). The LEM includes a stator, a translator, and two bearing housings. The stator includes a plurality of windings and a stator hole. The translator is configured to electromagnetically interact with the stator and is arranged to move axially along an axis substantially within the stator hole. The translator includes a translator bearing surface. A first bearing housing of the two bearing housings is coupled to the stator at a first longitudinal position, and a second bearing housing of the two bearing housings is coupled to the stator at a second longitudinal position. The first bearing housing and the translator bearing surface are capable of forming a first bearing gap, and the second bearing housing and the translator bearing surface are capable of forming a second bearing gap. For example, the first bearing gap and the second bearing gap can be configured to contain pressurized gas and serve as gas bearings. In another example, in some embodiments, the LEM is configured for oil-free operation.

[0006] In some embodiments, the translator includes a magnet segment. For example, the magnet segment and the stator bore can form a motor air gap. In some embodiments, the magnet segment includes a plurality of magnets arranged in longitudinally stacked rows. In some embodiments, an inner row of the longitudinally stacked rows includes magnets having a first axial length. In some such embodiments, a terminal row in the longitudinally stacked rows includes magnets having a second axial length, the second axial length being less than the first axial length. In some embodiments, the translator includes at least one structural feature that engages with at least one magnet of the magnet segment to constrain axial movement of the at least one magnet. In some embodiments, a plurality of magnets are bonded to a surface of the translator. In some embodiments, the translator includes a wrap radially located on the magnet segment. For example, the wrap constrains lateral displacement of the magnet.

[0007] In some embodiments, the magnet segment comprises a first longitudinal length and the plurality of windings comprises a second longitudinal length. The second longitudinal length may be greater than, equal to, or less than the first longitudinal length. In some embodiments, the magnet segment comprises a pole length and the stator comprises a plurality of slots and teeth having a slot pitch. In some such embodiments, the pole length and the slot pitch are substantially unequal.

[0008] In some embodiments, the plurality of windings are grouped into a plurality of phases, and each phase in the plurality of phases includes one or more windings in the plurality of windings. For example, in some embodiments, the plurality of phases is equal to or greater than three phases. In another example, each winding in the plurality of windings corresponds to a phase.

[0009] In some embodiments, the magnet segment includes a plurality of magnets, and the stator includes a plurality of stator teeth arranged azimuthally around a stator hole. The plurality of stator teeth include a pair of consecutive stator teeth having a first azimuth gap. The magnet segment includes a second azimuth gap between azimuthally consecutive magnets of the magnet segment. The first azimuth gap and the second azimuth gap are configured to substantially maintain azimuth alignment. In some embodiments, the first azimuth gap is larger than the second azimuth gap in the azimuth direction. In some embodiments, the translator includes a feature configured to constrain azimuth rotation.

[0010] In some embodiments, the first bearing housing is coupled to the stator via a first flexure assembly configured to provide mechanical stiffness at least for lateral displacement, and the second bearing housing is affixed to the stator via a second flexure assembly configured to provide mechanical stiffness at least for lateral displacement.

[0011] In some embodiments, the present disclosure relates to a linear machine. The linear machine includes a stator having a stator hole, a translator, at least one bearing housing including a surface, and an assembly configured to attach at least one bearing housing to the stator. The translator is configured to move linearly relative to the stator. In some embodiments, the translator includes a magnet segment and a bearing surface. The stator hole and the magnet segment form a motor air gap. The bearing surface and the surface form a bearing interface that enables the translator to align with at least one bearing housing. To maintain the motor air gap, the assembly provides relatively greater stiffness to lateral displacement than to the pitch and roll of the bearing housing. In some embodiments, the bearing housing is axially positioned so as to allow the magnet segment of the translator to travel beyond the end of the stator, beyond the axial length of the hoop stack of the stator, or beyond both the end of the stator and the axial length of the hoop stack of the stator.

[0012] In some embodiments, the translator includes a translator tube, the magnet segments are attached to the translator tube, and the bearing surface includes an outer surface of the translator tube.

[0013] In some embodiments, the assembly includes at least one mount rigidly attached to the stator and at least one flexure attached to the at least one mount and the at least one bearing housing. The at least one flexure provides relatively greater stiffness to lateral displacements than to pitch and roll of the bearing housing. In some embodiments, a fixing device such as a ball joint may be used instead of or in addition to the flexure.

[0014] In some embodiments, the bearing housing extends at least partially azimuthally around the bearing surface, and the at least one flexure extends at least partially azimuthally around the bearing housing.

[0015] In some embodiments, the bearing interface is a gas bearing interface and the linear machine is configured for oil-free operation, or otherwise operates without a liquid lubricant. In some embodiments, the bearing interface is a liquid or solid interface and the linear machine is configured for oil-free operation. For example, pressurized gas is provided to a gas bearing to provide stiffness against lateral displacement. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] According to one or more various embodiments, the present disclosure is described in detail with reference to the following drawings. The drawings are provided for illustrative purposes only and depict only typical or exemplary embodiments. These drawings are provided to facilitate understanding of the concepts disclosed herein and should not be construed as limiting the breadth, scope, or applicability of these concepts. It should be noted that for clarity and ease of description, these drawings are not necessarily drawn to scale.

[0017] Figure 1shows a cross-sectional view of an illustrative linear electromagnetic machine according to some embodiments of the present disclosure;

[0018] Figure 2 shows a perspective view of an illustrative linear electromagnetic machine with cooling according to some embodiments of the present disclosure;

[0019] Figure 3 shows a perspective view of an illustrative linear electromagnetic machine including a hoop stack and a spine according to some embodiments of the present disclosure;

[0020] Figure 4 shows a perspective view of an illustrative stator according to some embodiments of the present disclosure;

[0021] Figure 5 shows a perspective view of an illustrative hoop according to some embodiments of the present disclosure;

[0022] Figure 6 shows an axial view and a perspective view of an illustrative stator tooth including a plurality of laminations according to some embodiments of the present disclosure;

[0023] Figure 7 shows a perspective view of an exemplary hoop arranged with a set of stator teeth according to some embodiments of the present disclosure;

[0024] Figure 8 shows axial and perspective views of illustrative coils according to some embodiments of the present disclosure;

[0025] Fig. 9 shows a perspective view of an illustrative spine according to some embodiments of the present disclosure;

[0026] Fig.10 shows a perspective view of an exemplary end plate according to some embodiments of the present disclosure;

[0027] Fig.11 shows a perspective view of an illustrative assembly including end plates, a hoop coil, and a spine according to some embodiments of the present disclosure;

[0028] Fig.12 shows a perspective view of an illustrative assembly including an end plate, some hoop coils, and a spine according to some embodiments of the present disclosure;

[0029] Fig.13 shows a perspective view of an illustrative assembly stator including an end plate, a hoop, and a spine according to some embodiments of the present disclosure;

[0030] Fig.14 shows a side view of an exemplary axial lamination stack and a perspective view of a set of illustrative axial lamination stacks according to some embodiments of the present disclosure;

[0031] Fig.15 shows a side view of an illustrative hoop coil and spine with lead management and azimuthal clearance according to some embodiments of the present disclosure;

[0032] Fig.16 shows a side view of an illustrative translator according to some embodiments of the present disclosure;

[0033] Fig.17 Some embodiments of the present disclosure are shown Fig.16 An axial end view of a translator;

[0034] Fig.18 shows a cross-sectional side view of an end of an illustrative translator tube and track according to some embodiments of the present disclosure;

[0035] Fig.19 shows a top view of a portion of an illustrative translator having magnet segments according to some embodiments of the present disclosure;

[0036] Fig. 20 shows a perspective view of a portion of an illustrative translator having features for arranging magnets according to some embodiments of the present disclosure;

[0037] Fig.21 shows a perspective view of a portion of an illustrative translator segment with magnets arranged therein, according to some embodiments of the present disclosure;

[0038] Fig. 22 shows a cross-sectional view of a portion of an illustrative magnet segment according to some embodiments of the present disclosure;

[0039] Fig.23 shows a perspective view of an illustrative translator with an enclosure according to some embodiments of the present disclosure;

[0040] Fig.24 shows a perspective view of an exemplary bearing housing according to some embodiments of the present disclosure;

[0041] Fig.25 shows side and front views of a portion of an illustrative assembly including a bearing housing, a bearing mount, a flexure, and a flexure mount according to some embodiments of the present disclosure;

[0042] Fig.26 shows a cutaway cross-sectional view of an illustrative translator and stator according to some embodiments of the present disclosure;

[0043] Fig. 27 shows a cross-sectional view of an illustrative translator and bearing housing according to some embodiments of the present disclosure;

[0044] Fig.28shows an end view of an illustrative translator and additional components according to some embodiments of the present disclosure;

[0045] Fig.29 shows a cross-sectional view of an illustrative translator and stator according to some embodiments of the present disclosure;

[0046] Fig.30 shows a cross-sectional view of an illustrative translator and stator according to some embodiments of the present disclosure;

[0047] Fig.31 shows a block diagram of an exemplary LEM including an exemplary motor air gap according to some embodiments of the present disclosure;

[0048] Fig.32 shows a block diagram of an illustrative motor air gap having a magnetic pole pitch configuration according to some embodiments of the present disclosure;

[0049] Fig.33 shows a block diagram of an illustrative LEM system according to some embodiments of the present disclosure;

[0050] Fig.34 A diagram showing an illustrative system according to some embodiments of the present disclosure;

[0051] Fig.35 shows a block diagram of an illustrative phase control system according to some embodiments of the present disclosure; and

[0052] Fig.36 A cross-sectional side view of an illustrative generator assembly is shown, according to some embodiments of the present disclosure. DETAILED DESCRIPTION

[0053] The present disclosure relates to a linear motor, its components, and a method for controlling a linear motor. The linear motor includes a fixed component, namely a stator, and a movable part, namely a translator. The stator and the translator are configured to interact electromagnetically with each other. For example, the stator may include one or more phases, and the translator may include a magnet segment having one or more magnets. The movement of the translator may be affected by the current in the windings of the phases. For illustration, the current in the phase can be controlled to move the translator by applying a force in the direction of motion of the translator (e.g., acting as a motor), or the current in the phase can be controlled to decelerate (i.e., brake) the translator by applying a force opposite to the direction of motion of the translator (e.g., acting as a generator). Alternatively, in a linear electrical system such as a generator, the current induced in the winding can be extracted as electrical energy. The bearing system keeps the translator aligned relative to the stator and possibly other components to achieve a desired or predictable trajectory. For example, the bearing system can constrain the movement of the translator in a direction away from the expected trajectory.

[0054] Figure 1-3An illustrative linear electromagnetic machine (LEM) is shown in accordance with some embodiments of the present disclosure.

[0055] Figure 1 A cross-sectional view of an illustrative LEM 100 according to some embodiments of the present disclosure is shown. LEM 100 includes a translator 160, a stator 150, bearing housings 102 and 104, bearing mounts 103 and 105, flexures 113 and 115, features 123-126, and bearing interfaces 112 and 114. Translator 160 includes a segment 163 and a tube 162 configured to electromagnetically interact with stator 150. For example, segment 163 (also referred to as an "electromagnetic segment" or "magnet segment") may include a magnet segment having a permanent magnet, an electromagnet, an inductive portion, or a combination thereof. Although referred to as a tube, tube 162 may have any suitable cross-sectional shape, and correspondingly bearing interfaces 112 and 114 may have corresponding shapes. For example, in some embodiments, tube 162 may have a rectangular cross-section, and correspondingly, bearing interfaces 112 and 114 may be flat rather than annular. In further examples, in some embodiments, the tube 162 can have at least one circular cross-section at a first longitudinal distance (ie, axial distance) and at least one rectangular cross-section at a second longitudinal distance, where the first and second longitudinal distances can be equal or different.

[0056] The stator 150 and the segments 163 electromagnetically interact to cause motion of the translator 160, affect motion of the translator 160, convert kinetic energy of the translator 160 (e.g., based on the velocity mass of the translator 160) into electrical energy (e.g., in the windings of the phases of the stator 150 and, if desired, in power electronics coupled to the windings), convert electrical energy (e.g., in the windings of the phases of the stator 150 and, if desired, in power electronics coupled to the windings) into kinetic energy of the translator 160, or a combination thereof. The motor gap 151 (referred to as the "motor air gap") between the stator 150 (e.g., the laminated iron teeth of the stator) and the segments 163 (e.g., the permanent magnets thereof) affects the reluctance of the electromagnetic interaction between the stator 150 and the translator 160. For example, the smaller the motor gap 151, the greater the motor force constant (e.g., greater magnetic flux) that can be achieved between the stator 150 and the translator 160. However, if the motor gap 151 approaches zero (e.g., at one or more locations), the translator 160 may contact the stator 150, causing friction, impact, deformation, electrical shorting, reduced performance, failure, or any combination thereof. Therefore, bearings are used to maintain the lateral alignment of the stator 150 and the translator 160 (e.g., to maintain the motor gap 151 within an operable range).

[0057] In some embodiments, as shown, bearing housings 102 and 104 are attached to stator 150 via bearing mounts 103 and 105 and flexures 113 and 115. For example, by rigidly attaching bearing housings 102 and 104 to stator 150 can help offset lateral (e.g., radial) loads applied to translator 160. In some embodiments, one or both of bearing housings 102 and 104 can be coupled to stator 150 via flexures 113 and 115 to provide stiffness or compliance in one or more directions. In some embodiments, flexures 113 and 115 can be attached to stator 150, and bearing housings 103 and 105 need not be included. In some embodiments, flexures 113 and 115 do not need to be included, and bearing housings 103 and 105 can be attached to bearing housings 102 and 104, respectively. In some embodiments, one or both of bearing housings 102 and 104 need not be attached to stator 150, but can be attached to any other suitable fixed component (e.g., an external frame). In some embodiments, only one bearing housing is needed (eg, bearing housing 102 or bearing housing 104). To illustrate, a cantilevered mounting of a bearing housing to support a translator may provide minimal constraints on the translator, which provides greater tolerance for misalignment.

[0058] In some embodiments, one or both bearing interfaces 112 and 114 are configured as contact bearings. In some embodiments, one or both bearing interfaces 112 and 114 are configured as non-contact bearings. In some embodiments, one or both bearing interfaces 112 and 114 are configured as gas bearings (e.g., a non-contact bearing). In some such embodiments, one or both bearing housings 102 and 104 are configured to receive bearing gas from features 123-126, which may include respective ports for receiving respective bearing gas supplies. For example, with reference to the tubular geometry, each of the bearing housings 102 and 104 may include a bearing surface disposed at a radially inward surface, the bearing surface being configured to interface with respective annular gas bearings in the bearing interfaces 112 and 114. The tube 162 may include a cylindrical bearing surface configured to interface with the annular bearing interfaces 112 and 114. During operation, bearing interfaces 112 and 114 allow translator 160 to move along axis 190 with low or near zero friction and prevent significant lateral (e.g., radial) movement away from axis 190. For example, bearing interfaces 112 and 114 can be configured to maintain a motor air gap 151 between stator 150 (e.g., stator iron teeth and their copper windings) and segment 163 during operation. It will be understood that bearing interfaces 112 and 114 and motor air gap 151 can each have any suitable thickness. For example, in general, the thickness is preferably as thin as possible while ensuring reliable operation. In some embodiments, bearing interfaces 112 and 114 are configured to be 20-150 microns thick, and motor air gap 151 is configured to be 20-40 mm thick.

[0059] In the illustrative example where bearing interfaces 112 and 114 are configured as gas bearings, the bearing gas is configured to exit bearing housings 102 and 104 along a substantially radially inward direction (i.e., a streamline directed toward axis 190) (e.g., to form respective gas bearings in bearing interfaces 112 and 114). The bearing gas may flow through porous portions of bearing housings 102 and 104, conduits and orifices within bearing housings 102 and 104, or a combination thereof, to reach respective bearing interfaces 112 and 114.

[0060] In some embodiments, the bearing housings 102 and 104 may include a coating, a consumable layer, a dry film lubricant, a wear-resistant coating, or a combination thereof at the corresponding bearing surfaces to accommodate, for example, contact with the translator 160 while limiting or avoiding damage to the translator, the bearing housing, or both. In some embodiments, the translator 160 may include a coating, a consumable layer, a dry film lubricant, a wear-resistant coating, or a combination thereof to accommodate, for example, contact with the bearing housings 102 and 104 while limiting or avoiding damage to the translator, the bearing housing, or both. In some embodiments, the bearing housing extends completely and continuously (e.g., along 360° in azimuth) around the translator. In some embodiments, the bearing housing includes one or more bearing segments that extend around the translator over an azimuth range of less than 360°. For example, the bearing housing may include four bearing segments, each of which extends about ninety degrees around the translator with azimuth gaps between the bearing segments. The bearing housing may include any suitable number of bearing segments having any suitable number of gaps and arranged around the translator in any suitable configuration.

[0061] In some embodiments, translator 160 may include one or more pistons or end caps attached to the axial ends of tube 162. For example, tube 162 may serve as a rigid body to couple pistons and other components to form a rigid translator. In other examples, LEM 100 may be used as part of a linear generator (e.g., as Fig.36 ) is included, where one piston is configured to contact the reaction section and the other piston is configured to contact the gas spring. Figure 1 1 and 2 show that the segment 163 is axially shorter than the stator 150, but according to some embodiments of the present disclosure, the segment 163 may be axially shorter than the stator 150, longer than the stator 150, or the same length as the stator 150. In some embodiments, whether the segment 163 is longer, shorter, or the same length as the stator 150, the segment 163 or a portion thereof can be axially positioned outside the stator 150 (e.g., axially beyond the end of the stator 150).

[0062] Figure 2A perspective view of an illustrative LEM 200 with cooling according to some embodiments of the present disclosure is shown. LEM 200 includes a stator 250, a translator 260, bearing assemblies 202 and 204, and a cooling system 270. Translator 260 is configured to move along axis 290, which is constrained by bearing assemblies 202 and 204. Stator 250, which may include multiple phases, is configured to electromagnetically interact with a segment of translator 260, which may include a permanent magnet, an electromagnet, an inductive portion, or a combination thereof. Bearing assemblies 202 and 204 may each include one or more bearing housings, one or more mounts, one or more flexures, any other suitable components, or any suitable combination thereof to form a bearing interface with translator 160 (e.g., its surface 262 may be used as a bearing surface). In some embodiments, LEM 200 may be configured for air cooling, liquid cooling, or both. The cooling system 270 may include a plenum, a jacket, a shroud, a shield, vanes, any other suitable hardware, or any combination thereof, to direct cooling fluid around the components of the stator 250. For example, the LEM 200 may be configured for air cooling, and the cooling system 270 may include a cooling jacket, a shroud, or both, configured to receive and direct cooling air throughout the stator 250. In another example, the LEM 200 may be configured for liquid cooling, and the cooling system 270 may include a cooling jacket configured to receive and direct cooling fluid through the stator 250. In some embodiments, as shown, the stator 250 includes a spine 208 and an end plate 210, which will be Figure 4-13 As shown, the bearing assembly 202 includes a bearing housing 225, a flexure 221, a mount 222, and a feature 220 (e.g., which may include a feature for adjusting the bearing stiffness or a port for bearing gas). In some embodiments, a tie rod 251 is included to provide axial compression to components of the stator 250. For example, the tie rod 251 may include a segment (e.g., a threaded segment) extending axially through the end plate 210 at each end, with washers, nuts, crimp connectors, or other terminal pieces attached to these segments to engage the end plate 210 and maintain compression.

[0063] Figure 3A perspective view of an illustrative linear electromagnetic machine 300 including a hoop stack 351 and a spine 352 is shown according to some embodiments of the present disclosure. The hoop stack 351 includes a plurality of hoops (e.g., including hoop 353 shown, for reference) arranged along an axis 390 to form a stator bore (e.g., formed by stator teeth of hoops attached to the hoop stack 351). As shown, the hoop stack 351 includes an end plate 354 arranged on respective axial ends of the plurality of hoops for structural support. The spine 353 is coupled to the end plate 354 and the hoops of the hoop stack 351 to maintain alignment of the hoops. In some embodiments, one or more optional tie rods 359 may be included to provide axial compression to the hoop stack 351 (e.g., the tie rods 359 may engage with the end plate 354). The bearing assemblies 302 and 304 maintain alignment between the stator 350 and the translator 360 (e.g., lateral alignment of the motor gap). For example, in Figure 4-13 The hoops, coils, stator teeth, and their components are further described in the context of FIG.

[0064] The stator is a LEM component that is configured to accommodate current in one or more phases, electromotive force in one or more phases, or both to provide electromagnetic interaction with the translator. The electromagnetic interaction includes flux interaction (e.g., having a motor air gap that affects magnetic resistance), force interaction (e.g., having a force constant that affects the current-force relationship), or both.

[0065] Figure 4 A perspective view of an illustrative stator 400 is shown in accordance with some embodiments of the present disclosure. The stator 400 includes a plurality of stator teeth 402 (e.g., iron elements, lamination stacks, or both) arranged to form a stator bore, as shown. Although shown as circular, the stator teeth may define any suitable composite surface (e.g., flat, curved, segmented, segmented, circular, non-circular, or other) that may define an air gap in the motor. In some embodiments, the spine 452, end plates 454, and tie rods 452, or any combination thereof, provide structural support to maintain alignment of the stator 400. Leads 413 from multiple windings of the stator 400 may be directed to power electronics, may be coupled between subsets thereof (e.g., to form a star neutral, directly coupling two or more windings in series), or a combination thereof. Although in Figure 4 400 to constrain lateral displacement of a translator configured to electromagnetically interact with stator 400 (e.g., to form a motor air gap with stator 400). In some embodiments, tie rods 451 are included to provide axial compression to components of stator 400 (e.g., hoop coils, stator teeth 402, or both).

[0066] A stator (e.g., stator 400) may include a plurality of ferrous elements for directing magnetic flux. These ferrous elements or "stator teeth" may include ferrous elements arranged in a circular pattern (e.g., as shown in FIG. Figure 5 and Figure 7 As shown, a certain number of laminations are stacked (for example, as shown in FIG. Figure 6 As shown). The lamination stacks are each linear stacks that, when arranged in a circle, can together approximate a circular stator hole. Including more stator teeth can provide a more uniform air gap (e.g., between the teeth and the translator with the magnet segment), allow a tighter air gap, potentially allow better motor performance, or a combination thereof. Including fewer stator teeth can reduce the number of parts and assembly costs. In some embodiments, to achieve high reliability, the cooling system provides stator and winding cooling, the stator is configured for easy wiring of phase leads, the stator is configured to provide space for insulating material (e.g., dielectric insulation, thermal insulation, or both), or a combination thereof.

[0067] Figure 5 A perspective view of an illustrative hoop 500 according to some embodiments of the present disclosure is shown. Hoop 500 is configured to accommodate a set of stator teeth that are at least partially arranged azimuthally about an axis 590 of hoop 500 (e.g., azimuthally about axis 592). For reference, as shown in FIG. Figure 5 As shown, axis 592 represents the axial direction (i.e., longitudinal direction), axis 591 represents the radial direction (i.e., lateral direction), and axis 590 represents the azimuthal direction. Hoop 500 includes body 501 (e.g., main structural portion or "reinforcement ring"), optional recess 504 configured to receive or otherwise engage one or more vertebrae, optional anti-deformation tab 502, and optional abutment 503. For example, in Figure 5Four recesses 504 are shown in the figure, although any suitable number of recesses may be included to accommodate corresponding spines. In some embodiments, the hoop does not include recesses, and the spine is connected to the hoop 500 with or without any additional features. The anti-deformation tab 502 extends axially from the body 501 and is configured to prevent azimuthal or lateral deformation of the laminations of the stator teeth. In some embodiments, the anti-deformation tab 502 may include one or more holes or other features configured to allow cooling air flow to penetrate the stator (e.g., flow through the anti-deformation tab 502 to the windings and stator teeth). The docking portion 503 is configured to accommodate or otherwise engage a feature of the stator tooth to maintain the position of the stator tooth, react to forces on the stator, or both. The hoop 500 can be constructed of metal, metal sheet, plastic, or any other sheet material, including any suitable processing (e.g., bending, breaking, pressing / stamping, cutting, brazing, welding, adhering, or other) to form shapes, forming features, attaching features, or any combination thereof (e.g., anti-deformation tabs 502, recesses 504, butt joints 503).

[0068] Figure 6 An axial view and a perspective view of an illustrative stator tooth 600 are shown according to some embodiments of the present disclosure, the stator tooth 600 comprising a plurality of laminations. Lamination 601 is shown illustrating a sheet of material from which the stator tooth is formed. A plurality of laminations similar to 601 (although they need not be identical) are stacked to form the stator tooth 600. For example, a plurality of steel laminations may be cut from a sheet of metal (e.g., by stamping, laser cutting, plasma cutting, wire cutting, water jet cutting, or any other cutting technique) and then attached to each other (e.g., bonding, interlocking, welding, bolting, or any other suitable means) to form a stack of laminations (i.e., the stator tooth 600). For reference with respect to the stator, as shown in FIG. Figure 6 As shown, axis 692 represents an axial direction, axis 691 represents a radial direction, and axis 690 represents an azimuthal direction (e.g., an azimuth angle about axis 692). As shown, stator tooth 600 includes features 650 and 651 for axially engaging stator teeth. Features 650 and 651 may include bosses, recesses, grooves, slots, steps, raised portions, any other suitable geometric features for engaging axially adjacent stator teeth (e.g., attaching to adjacent hoops), or any combination thereof. In some embodiments, features 650 and 651 provide for assembling a hoop stack (e.g., Figure 3 An indexing feature of a hoop stack 351 in the embodiment of the present invention, an ...

[0069] Region 605 represents a recess configured to accommodate one or more windings. For example, regions similar to region 605 of a stator tooth at a particular axial position are aligned to form a void volume in which a conductive winding (e.g., a conductive winding of a coil) can be wound or otherwise inserted. In some embodiments, the stator tooth 600 or region 605 thereof is wrapped or otherwise covered with an electrically insulating material (e.g., a Nomex sheet) to prevent the winding from electrically shorting to the stator tooth 600. In alternative embodiments, the conductive winding is wrapped or otherwise covered with an electrically insulating material (e.g., a Nomex tape) to prevent the winding from electrically shorting to the stator tooth 600. Feature 603 (including the notch shown) is configured to allow the stator tooth 600 to engage with a hoop (e.g., as Figure 7 For example, feature 603 may be Figure 5 The stator tooth ends 604 (also referred to as stator tooth tips) are used to define a stator hole together with similar features of multiple stator teeth. In some embodiments, the shape of the stator tooth ends 604 can be flat in the azimuthal direction (e.g., in the 690 direction). In alternative embodiments, the shape of the stator tooth ends 604 can have a convex shape, a concave shape, or any other suitable shape required to provide a desired stator hole surface. As shown in dashed outline in the front view, the stator tooth ends 604 can be curved or otherwise contoured to be closer to a circle (e.g., a circular stator hole).

[0070] In one illustrative example, laminations 601 may include thin, low-loss, high-permeability steel laminations. In another illustrative example, laminations 601 may optimize the stator tooth shape to form the motor air gap and provide high copper slot filling (e.g., more windings or winding turns). Figure 6 As shown, the laminations (e.g., laminations 601) of the stator tooth 600 have a sufficiently uniform thickness so that the stator tooth 600 has a rectangular profile when viewed in the axial direction. In some embodiments, the thickness of the laminations 601 does not have to be uniform. For example, the thickness of the laminations 601 at the stator tooth end 604 can be less than the thickness at the outer radial end (e.g., where the feature 603 is located) so that when the stator tooth 600 is formed, the stator tooth 600 forms a V-shaped profile when viewed in the axial direction (e.g., the inner surface of the stator tooth is smaller than the outer surface area of ​​the stator tooth). The V-shaped profile can reduce or eliminate the azimuthal gap between adjacent stator teeth at the outer diameter of a set of stator teeth (e.g., as shown in FIG. 2 ). Figure 7 The stator ring gear shown in Figure 1 increases the amount of steel material in the stator, which can reduce the magnetic flux density and improve efficiency.

[0071] Figure 7A perspective view of an illustrative hoop 701 is shown, according to some embodiments of the present disclosure, the hoop being arranged with a set of stator teeth 702 ("hoop tooth assembly"). The set of stator teeth 702 locally defines a stator hole 703 at a specific axial position or range of positions. Each tooth in the set of stator teeth 702 engages with a docking portion of the hoop 701 (e.g., docking portion 753 is one of them). In some embodiments, each docking portion 753 includes a feature 754 (e.g., a slot shown) that engages with a stator tooth (e.g., a stator tooth in stator teeth 702) and a feature 755 (e.g., a flexure shown) for retaining engagement. In some embodiments, the set of stator teeth 702 can be welded, brazed, glued, crimped, or otherwise attached to the hoop 701, and the feature 755 can be, but is not necessarily, included. The feature 756 (e.g., one or more retainers shown) is configured to provide a path for cooling air to flow to help cool the coil (or its windings), stator teeth, hoop, spine, tie rod, or a combination thereof. In some embodiments, feature 756 may be selectively covered to divide a section of the stator into two or more cooling zones.

[0072] In some embodiments, as shown, the group of stator teeth 702 includes an azimuth gap 704, which is configured to provide an anti-rotation force on the translator, is configured to allow the feature of the translator to move more finely (e.g., a track), allows the coil leads to be away from the winding wiring, or any combination thereof. In some embodiments, a lead cover 705 may be included to guide the coil leads away from the winding, provide alignment of the stator teeth, or both. For example, the lead cover 705 may include an internal channel to keep the coil leads away from the winding wiring or guide. In addition, the lead cover 705 may be composed of a dielectric material (e.g., plastic) to electrically insulate the coil leads from the group of stator teeth 702 and the reinforcement ring 701. In some embodiments, one or more azimuth gaps at the stator hole 703 may be included between the group of stator teeth. In some embodiments, a substantially significant azimuth gap at the stator hole 703 is not included between the group of stator teeth. In some embodiments, one or more azimuth gaps at the stator hole 703 are included and are configured to provide an anti-rotation force. Features 711 (eg, one or more holes as shown) may be included to accommodate tie rods, provide an axial cooling path for cooling air, or both.

[0073] In one illustrative example, the hoop can be a stamping that is used to control the roundness of a single tooth array. When many tooth arrays are stacked axially in series, the hoop, together with any suitable number or type of spines and any suitable number or type of end plates, controls the straightness of the stator bore. The hoop can include any suitable features to attach, engage, preload, or any combination thereof, the lamination stack into an aligned position of these features to reliably define the stator bore, allow snap-fit ​​assembly together, or both. The stacked assembly allows the use of stator tooth ends (e.g., as Figure 6 The stator teeth are preferably provided with a plurality of tooth arrays (shown in Figure 1) to improve motor efficiency and reduce magnetic losses while still allowing easy coil insertion, good slot filling, and simple stator assembly. In some embodiments, the stator teeth include alignment bosses and recesses that are stamped into the laminations to provide positive alignment when multiple tooth arrays are axially stacked together.

[0074] In some embodiments, the stack of hoop tooth assemblies is compressed to increase the stiffness of the stator assembly. In some embodiments, the hoop tooth assemblies can be assembled under compression and secured in place by tie rods, welds, glue, or a combination thereof. In some such embodiments, features (e.g., tabs) are included to prevent individual lamination stacks or stator teeth from buckling or deforming when loaded in compression (e.g., by using anti-deformation tabs). These features can be separate components or can be integrated into the hoop design.

[0075] In some embodiments, a set of stator teeth may include azimuthal gaps at a radially outer region of the stator tooth ring (e.g., based on the tooth design). These gaps may be filled or otherwise eliminated by including a stator tooth lamination of greater thickness at the radially outer ends (e.g., so that the stator teeth taper azimuthally at a smaller radius). For example, when viewed in the axial direction, the stator teeth may have a V-shape in the radial direction, rather than a uniform thickness. Using a V-shape may improve electromagnetic performance, but may increase resistance to the flow of cooling fluid through the stator.

[0076] Figure 8An axial view and a perspective view of an illustrative coil 800 according to some embodiments of the present disclosure are shown. Coil 800 includes a winding 802 and a lead 804. In some embodiments, as shown, coil 800 includes a section of conductive material wrapped in a suitable shape (e.g., the circle shown) to form a winding (i.e., winding 802). The rest of the conductive material forms a lead (i.e., lead 804). For example, lead 804 can be connected to other leads (e.g., leads of other coils), power electronics, electrical terminals, neutral Y-type connectors, any other suitable connectors or any combination thereof. In an illustrative example, when coil 800 is included in a phase controlled by a full bridge, two leads 804 can be connected to a suitable node of an H-bridge circuit for current control. In another illustrative example, when coil 800 is included in a phase controlled by a half bridge, one of the leads 804 can be connected to a suitable node of a half bridge circuit for current control, and another of the leads 804 can be connected to a neutral Y-type connector. In further illustrative examples, when coil 800 is included in one phase, two leads 804 may be coupled to leads of other coils (eg, the phase includes more than one coil).

[0077] In some embodiments, the coil 800 can be formed by copper wire, aluminum wire, any other suitable metal wire or any combination thereof. For example, a copper wire having N stacked strands (e.g., where N is an integer) can be wound (e.g., around a mandrel or other tool to define a coil hole 830) to form a winding 802, and the unwound end forms a lead 804 (e.g., a lead of any suitable length). In some embodiments, as shown, the winding 802, the lead 804, or both can be wrapped with an electrically insulating material to prevent short circuits (e.g., such as Nomex, Kapton, or other suitable one or more materials). In some embodiments, the lead 804 includes an electrical terminal at the end (e.g., a crimped connector, a soldered end, or other suitable components or treatments). In some embodiments, the coil hole 830 is the same as or larger than the stator hole. For example, the coil hole 830 can be larger than the stator hole to prevent the winding 802 from accidentally contacting the translator. In another example, the coil hole 830 can be larger than the stator hole, and the radially inner portion of the stator tooth is arranged radially inward of the coil hole 830. A plurality of coils (each similar to coil 800) may be included in a stator (eg, Figure 4stator 400), thereby constituting the phases of the stator. For example, each phase may include one or more coils electrically connected in series. In another example, each phase may include one coil. In some embodiments, a coil or its winding may be formed using a bondable wire, a wire with bondable insulation, or both. For example, a coil is formed and then the coil or its winding portion is heated (e.g., baked in an oven) to fix. The coil may include a wire having any suitable cross-section, such as a circular, square, or any other suitable shape. The coil may include a wire of any suitable material (e.g., copper, aluminum) or any other suitable wire.

[0078] Fig. 9 A perspective view of an illustrative spine 900 according to some embodiments of the present disclosure is shown. The spine 900 is configured to position, arrange, maintain, align, or otherwise affect the axial stacking of the hoops of the stator. The spine 900 includes a length 901 that is configured to axially straddle one or more hoops of the stator. The spine 900 can be configured to provide axial stiffness, azimuthal stiffness, lateral stiffness (e.g., radial), or a combination thereof for the stacking of hoops. The stator can include any suitable number of spines having any suitable shape. For example, although illustrated as a rectangle, the spine can be curved (e.g., following an arc along an azimuthal angle), segmented, bent, defined by a regular or irregular shape in a plane, or any other suitable shape. In some embodiments, as shown, the spine 900 includes a feature 902 for attaching or otherwise coupling to the hoop of the stator. The feature 902 can include, for example, a hole, a slot, a recess, a boss, a tooth, a pin, a threaded fastener (e.g., a threaded stud), any other suitable feature, or any combination thereof, to position and maintain the arrangement of the hoop. Stator (e.g. Figure 4 One or more spines, each similar to spine 900, may be included in the stator 400 of the embodiment of the present invention to provide structural support, alignment, or both for the stator and its components. In some embodiments, spine 900 spans the length of a single hoop and is attached to other spines in an axial direction so that when stacked axially, the spines collectively span the length of the stator. In some embodiments, spine 900 spans the length of multiple hoops and is attached to other similar spines in an axial direction so that when stacked axially, the spines collectively span the length of the stator. In some embodiments, the spines help define the stator bore by aligning the stator teeth included in the hoop tooth assembly. In addition, during operation, the spines provide stiffness to resist twisting or other displacement of the stator teeth, and therefore potentially resist twisting or other displacement of the stator bore.

[0079] Fig.10A perspective view of an illustrative end plate 1000 is shown in accordance with some embodiments of the present disclosure. End plate 1000 is configured to define the axial extent of a hoop stack. For example, end plate 1000 may be similar to hoop 500, but without corresponding coils or stator teeth. In other examples, end plate 1000 may be similar to hoop 500 including corresponding coils or stator teeth. In other examples, end plate 1000 need not be similar to hoop 500, and may, but need not, include corresponding coils (or multiple coils) or stator teeth. In some embodiments, end plate 1000 is the same as a hoop (e.g., a terminal hoop at either axial end of the stator serves as an end plate without the need for a separate component). In some embodiments, end plate 1000 may be attached to or otherwise coupled to one or more spines (e.g., similar to Fig. 9 Spine 900). For example, feature 901 may include a hole, a slot, a recess, a boss, a tooth, a pin, a threaded fastener (e.g., a threaded stud), any other suitable feature, or any combination thereof, to interface with one or more spines. In some embodiments, end plate 1000 is structurally stiffer than each hoop of the stack to provide structural rigidity to the assembled stator. End plate 1000 includes end plate hole 1030 that is larger than the stator hole. End plate hole 1030 allows the translator to move axially without impeding the movement of the translator. In some embodiments, one or two end plates (each similar to end plate 1000) may be included in a stator (e.g., Figure 4 In the stator 400 of the present invention, the end plates are arranged at the longitudinal ends of the stator. For example, an end plate (e.g., including two end plates) may be included at each longitudinal end of the stator. In some embodiments, in addition to capping the ends of the stator, the end plate 1000 may be used in an intermediate position within the stator to provide additional structural support for the stator stack. In some embodiments, the end plate 1000 may be used to attach the bearing directly to the stator. In some embodiments, one or more end plates may be arranged within the hoop stack (e.g., between two hoop tooth assemblies). The end plate may have any suitable design configured to help hold the hoop together. The spine may have any suitable design configured to help hold the hoop together. In some embodiments, the stator does not have to include a spine, an end plate, or both. In some embodiments, the end plate 1000 includes a feature 1001 for docking with and engaging the spine. In some embodiments, the end plate 1000 includes a feature 1002 for docking with and engaging the tie rod.

[0080] Fig.11A perspective view of an illustrative assembly 1100 is shown, according to some embodiments of the present disclosure, comprising an end plate 1101, one hoop tooth assembly and one coil (collectively referred to as hoop coil assembly 1102 or "hoop coil"), and spines 1103 and 1104. The spines 1103 and 1104 are coupled to the end plate 1101, which defines a first axial side of the stator. The hoop coil assembly 1102 comprises a hoop, a set of stator teeth 1105, and one or more coils 1106 and is arranged axially in line with the end plate 1101 (e.g., along the axis of the stator). In some embodiments, the assembly 1100 is a first building block for a complete stator. Fig.12 A perspective view of an illustrative assembly 1200 is shown, according to some embodiments of the present disclosure, that includes an end plate 1101, a plurality of hoop coil assemblies 1202 (e.g., including hoop coil assembly 1102), and spines 1103 and 1104. Assembly 1200 is a partially assembled stator. Hoop coil assemblies 1202 are stacked along the axis of the stator. In some embodiments, leads 1213 of hoop coil assemblies 1202 are oriented in the same orientation, although they need not be. In some embodiments, assembly 1200 is for a complete stator (e.g., Fig.13 stator 1300) prerequisite. Fig.13 A perspective view of an illustrative assembled stator 1300 is shown according to some embodiments of the present disclosure, the assembled stator 1300 including end plates 1101 and 1301, hoop coils 1302 (e.g., including hoop coil assembly 1202), and spines 1103 and 1104. Hoop coil assemblies 1302 are stacked along the axis of stator 1300 to define a stator aperture (e.g., stator teeth 1305 define the stator aperture). For example, the stator aperture, together with the magnet segments of the translator, defines a motor air gap. In some embodiments, the leads 1313 of the hoop coil assemblies 1302 are oriented in the same orientation, although they need not be. In some embodiments, the leads 1313 are coupled to power electronics (e.g., such as Fig.33 , 3436), the power electronics being configured to control current in one or more of the leads 1313 (e.g., which may correspond to phases). In some embodiments, some of the leads 1313 are coupled to the power electronics, and some of the leads 1313 are coupled to other leads (e.g., to arrange the coils in series or in parallel, or to form a neutral Y-type or star-type node). In some embodiments, one or more of the hoop coil assemblies 1302 are attached to the spines 1103 and 1104 (e.g., by fastening, crimping, interlocking, pressing, tooth-slot docking, pinning, or otherwise positioning and constraining). In some embodiments, the spines 1103 and 1104 provide lateral alignment for the hoop coil assemblies 1302 (e.g., to ensure that the stator bore is substantially straight). The stator 1300 includes four spines as shown (e.g., spines 1103, 1104, 1304, and 1306), but the stator may include any suitable spines. In some embodiments, the axial length, number of phases, or both can be selected by forming a longer stack (e.g., using longer or shorter spines, using offset spines, and more or fewer hoop coils in the stack). In some embodiments, an optional tie rod 1351 can be included to provide axial compression. In some embodiments, the hoop coil assemblies are stacked so that adjacent hoop coil assemblies butt or engage at their respective stator tooth interfaces so that the stator teeth support any compressive loads in the axial direction, while optionally the hoops and spines remain aligned.

[0081] In an illustrative example, the end plates 1101 and 1301 can be configured to interface with a bearing mount, flexure, or bearing housing that is configured to constrain lateral (e.g., radial) displacement of a translator that is configured to electromagnetically interact with the stator 1300. In some embodiments, the hoop coil assembly adjacent the end plate need not have a coil at an axially outer end (e.g., between the hoop coil assembly and the end plate). For example, each hoop coil assembly in the stack can include two coils, one coil at each axial end of a stator tooth, except that the first hoop coil and the last hoop coil (e.g., away from the end plate) include coils only at the axially inner end. In some embodiments, each hoop coil assembly in the stack can include two coils, one coil at each axial end of a stator tooth, including the first hoop coil assembly and the last hoop coil assembly (e.g., the hoop coil assembly adjacent the end plate).

[0082] Fig.14A side view of an illustrative axial lamination 1400 and a perspective view of a set of illustrative axial lamination stacks 1450 are shown according to some embodiments of the present disclosure. Axial lamination 1400 includes a plurality of teeth (e.g., including tooth 1401) separated by a plurality of slots (e.g., slot 1402). As shown, lamination stack 1450 (e.g., including lamination stack 1460) includes a set of lamination stacks (each stack including a plurality of laminations similar to lamination 1400) arranged to form a stator aperture 1453. The set of stator teeth of lamination stack 1450 define stator aperture 1453. Slots 1454 extend azimuthally at least partially around stator aperture 1453, the stator aperture being arranged between axially consecutive rows of stator teeth. In some embodiments, wires may be wound in slots 1454 to form windings. In some embodiments, coils may be mounted in slots 1454, with phase leads routed in any suitable manner. In some embodiments, the axial length of the lamination stacks in the set of lamination stacks is equal to or less than the length of the stator. In some embodiments, the lamination stacks 1450 are arranged using structural and alignment fixtures, features, components, or any combination thereof. For example, the lamination stacks 1450 may be arranged by at least one hoop (e.g., similar to Figure 3 Hoop 353 in), spine (e.g., Figure 3 352 in the spine), end plates (e.g., Figure 3 end plates 354 in the embodiment), tie rods (e.g., Figure 3 The tie rods 359) or any combination thereof are structurally supported and aligned.

[0083] Fig.15An illustrative hoop coil 1500 with a lead management cover (e.g., using cover 1503), an azimuth gap 1504, and spines 1510-1513 are shown in accordance with some embodiments of the present disclosure. Hoop coil assembly 1500 includes hoop 1502, a set of stator teeth 1501, a coil (e.g., including windings 1520 and leads 1521 and 1522), and cover 1503. In some embodiments, as shown, azimuth gap 1504 is included between the set of stator teeth 1501 to affect an anti-clocking force on a translator configured to electromagnetically interact with a stator including hoop coil assembly 1500. Hoop 1502 is coupled to spines 1510, 1511, 1512 or is otherwise constrained from lateral movement (e.g., radially, azimuthally, or otherwise) by spines 1510, 1511, 1512, and 1513. Cover 1503 may, but need not, extend axially and radially across the entire hoop coil 1502, the cover being configured to protect and direct leads 1521 and 1522 away from winding 1520 to power electronics, leads of other windings, a neutral wye / star node, or any other suitable electrical terminal. In some embodiments, the presence of cover 1503 causes a second azimuthal gap between the set of stator teeth 1501. In some embodiments, the azimuthal gaps (e.g., azimuthal gap 1504 and the azimuthal gaps of cover 1503) may be located at any suitable azimuthal position (e.g., substantially 180 degrees apart), may have any suitable size (e.g., substantially the same size), or both. In some embodiments, one or more azimuthal gaps between stator teeth of a hoop coil assembly may be configured to affect anti-synchronization forces on a translator configured to electromagnetically interact with a stator including the hoop coil assembly. As shown, Figure 7Uniform azimuthal spacing between stator teeth is shown for teeth between azimuthal gap 1504 and azimuthal gap for cover 1503, but this is not required. In a hoop coil assembly, the stator teeth may be arranged with any suitable number of azimuthal gaps having any suitable size. In some embodiments, the hoop coil assembly may include two coils per hoop (e.g., on opposite axial sides of the set of stator teeth), although any suitable number of coils (e.g., one or more coils) may be included in a hoop coil. In some embodiments, the stator lamination tooth pitch (also referred to as the stator slot pitch) may vary from hoop coil assembly to hoop coil assembly, based on the axial position of the hoop coil assembly within the stator stack. In some embodiments, if the velocity profile of the translator is highest at the midpoint of the stroke (e.g., the center of the stator), it may be desirable to have a longer stator slot pitch in the middle of the stator because this can reduce the phase frequency and the resulting core losses. Similarly, if the velocity profile of the translator is lowest near the dead point of travel (e.g., the end of the stator), it may be desirable to have a shorter stator slot pitch at the ends of the stator because this can increase the phase frequency or EMF per turn, thereby allowing more work (i.e., force over a distance) to be contributed from the end windings. In some embodiments, hoop coil assemblies located at the end portions of the stator may include a shorter stator slot pitch than the stator slot pitch of hoop coil assemblies located in the center portion of the stator.

[0084] like Figure 11-13 As shown, a plurality of hoops (e.g., Fig.15 Multiple hoop coil assemblies 1500) can be stacked axially to form a stator. For example, multiple hoops with corresponding coils can be stacked along one or more spines (e.g., spines 1510-1513) for alignment, fixation, or both. In some embodiments, for each hoop coil assembly, the number of turns of the windings comprising the coils is the same. In some embodiments, the number of turns of the windings comprising the coils can vary from hoop coil assembly to hoop coil assembly. For example, in some embodiments, a hoop coil assembly positioned toward the end of the stator may include a coil having fewer turns of windings, a hoop coil assembly positioned toward the center of the stator may include a coil having more turns of windings, or a hoop coil assembly positioned toward the end of the stator may include a coil having fewer turns of windings and a hoop coil assembly positioned toward the center of the stator may include a coil having more turns of windings; or vice versa.

[0085] In some embodiments, the stator need not include a separate spine. For example, in some embodiments, multiple hoop coils can be stacked axially together, optionally aligned around a central core axis (e.g., as a substitute for a magnet segment plus a motor air gap), and then welded or bonded to each other. In other examples, the hoop coils can be placed under compression by axial preloading (e.g., placing the stack under compression with tie rods) and then welding, or axial preloading followed by clamping, or both. In some embodiments, multiple hoop coils can be stacked axially together and placed axially under compression using one or more tie rods extending through the stack of hoops. For example, in some embodiments, tie rods can be used in addition to or in place of the spine and end plates. In some embodiments, each axially stacked hoop is in contact with the spine, and the tie rods are used to place the axial stack of the hoop coil assembly under axial compression.

[0086] In some embodiments, components of the present disclosure are configured (e.g., to keep manufacturing costs low) to leverage existing motor manufacturing infrastructure (e.g., presses, molds, coil machines, insulation systems), efficiently utilize laminated sheets, provide compatibility with automated assembly and verification methods, allow streamlined manual assembly, and provide adequate cooling options to achieve high power density and low material and assembly costs.

[0087] In one illustrative example, exposed stator teeth (e.g., metal) and windings (e.g., copper or aluminum wire) around the radially outer portion of the stack assembly (i.e., stator) provide a path for passive or active motor cooling to control temperature and improve motor life (e.g., under high current loads), motor efficiency, motor power, or any combination thereof. In some embodiments, a shield (e.g., such as Figure 4 ), so as to more effectively direct cooling air into the magnetic air gaps between windings, between stator teeth, or a combination thereof.

[0088] The translation assembly or "translator" interacts electromagnetically with the stator to convert between electrical and kinetic energy. Thus, the translator is able to move under the action of electromagnetic forces, move under the action of any forces applied to the translator, generate electromotive force (emf) in each phase of the stator (e.g., and conversely react to the emf generated by the stator), achieve a nominal linear motion path, and withstand thermal and mechanical loads encountered during operation (e.g., cycling).

[0089] Fig.16 A side view of an illustrative translator 1600 is shown, in accordance with some embodiments of the present disclosure. Fig.17 An axial end view of translator 1600 is shown, in accordance with some embodiments of the present disclosure. Fig.16The axial end view is taken from direction 1601. The translator 1600 includes a tube 1612. The translator 1600 includes a section 1613, which may include a feature (e.g., a magnet) for achieving a desired electromagnetic interaction with the stator. The translator 1600 also optionally includes a track 1616, which is configured to provide a position index, an anti-synchronization bearing surface, or both. In some embodiments, the translator 1600 does not include a track, but instead provides sufficient anti-synchronization stiffness in the azimuthal direction through electromagnetic interaction between the translator and the stator (e.g., a stator with azimuthal gaps between stator teeth). In some embodiments, the translator 1600 or its components can be symmetrical about the axis 1690 (e.g., including a circular shape centered on the axis 1690, a fastener pattern, an arrangement of tracks, and other aspects having rotational symmetry). In some embodiments, the translator 1600 or its components need not be symmetrical about the axis 1690. In some embodiments, the section 1613 can have a diameter substantially the same as the tube 1612. In some embodiments, segment 1613 can have a diameter that is smaller or larger than tube 1612. In some embodiments, the outer dimensions of segment 1613, tube 1612, or both can be uniform, non-uniform, or both in the axial direction. For example, tube 1612 can include a taper, a step, or both. In another example, segment 1613 can have a larger diameter at or near its axial center. In some embodiments, translator 1600 can include several segments made of different materials. In some embodiments, the material composition of the segments of translator 1600 can be optimized for desired properties (e.g., weight, mechanical strength, and electrical or thermal properties).

[0090] Track 1616 includes, for example, a surface 1640 that may include a feature for position indication or indexing; a surface 1641 that may include an anti-sync bearing surface; and a surface 1642 that may include an anti-sync bearing surface. In some embodiments, according to the present disclosure, a translator may include zero, one, two, or more than two tracks having any suitable azimuthal or axial position on the translator. For example, in some embodiments, a translator may include more than one track to provide multiple position indications (e.g., for redundancy, accuracy, symmetry, or a combination thereof). In some embodiments, translator 1600 does not have to include any anti-sync tracks. In some embodiments, the magnetic interaction between the translator and the stator may provide sufficient anti-sync stiffness in the azimuthal direction. In some embodiments, in the absence of anti-sync track 1616, for example, the position indexing feature may be directly attached to translator 1600, directly integrated in translator 1600, or both (e.g., directly attached to tube 1612, directly integrated in tube 1612, or both). In some embodiments, surfaces 1641 and 1642 are configured to interface with corresponding anti-sync bearings (e.g., which may include anti-sync gas bearings). The anti-sync bearings may provide stiffness in the azimuth direction, thereby preventing or reducing azimuth movement of the translator. In some embodiments, surface 1640 may include machined features for position indication or indexing, magnetic tape for position indication or indexing, any other suitable features for position indication or indexing, or any combination thereof. In some embodiments, sensing the position of the translator relative to the stator may be determined by sensing the position of one or more rows of magnetic feature segments 1613 of the translator, with or without the use of external position indexing features. For example, the back electromotive force (emf) may be measured in one or more phase windings to determine the relative position of the stator and translator. In other examples, a control signal (e.g., a pulse width modulated signal for applying current), a measured current, or both may be used to determine the relative position of the stator and translator.

[0091] Fig.18A cross-sectional side view of an end of an illustrative translator tube 1810 and a track 1812 is shown in accordance with some embodiments of the present disclosure. For example, the track can be configured to constrain the rotational motion of the translator and / or to mount an encoder strip for position measurement. In some embodiments, the track is attached (e.g., bolted, welded, glued, tied, or any combination thereof) to the translator. The track 1812 can be attached to the translator tube 1810 by any suitable means, such as bolted, welded, glued, tied, or any combination thereof. In some embodiments, the track 1812 can be attached to the translator tube 1810 at any suitable location on the translator tube and at any suitable location on the track. For example, the track 1812 need not be attached to the translator tube 1810 over the entire axial length of the track (e.g., there can be portions of the track that are not attached to the translator tube).

[0092] Fig.19 1 shows a side view of a portion of an illustrative translator 1900 having a magnet segment 1913 according to some embodiments of the present disclosure. The translator 1900 includes a tube 1912 and a magnet segment 1913 (e.g., which may be similar to Fig.16 Segment 1613). The magnet segment can include any suitable features that can electromagnetically interact with the phases of the stator. For example, as shown, the magnet segment can include an array of magnets arranged in a north (N) and south (S) arrangement (e.g., with the N or S poles shown facing outward), a Halbach array, any other suitable magnetic array, or any combination thereof. In some embodiments, the axial lengths of the N and S magnet rows can be substantially the same or substantially different. For example, the magnet rows toward the axial ends of segment 1913 can contribute less to the generation of the magnetic field and can be shorter in axial length (e.g., as shown) compared to the magnet rows toward the axial center of segment 1913. Fig. 22 ). Magnet segment 1913 includes optional end features 1920 and 1921 that are used to outline the magnet segment 1913 and can serve to help transfer forces (e.g., axial forces) applied to translator 1900. Magnet segment 1913 also includes optional positioning features 1922 that are configured to position rows of magnets of the same polarity arrangement. Positioning features 1922 can be configured to position magnets in rows, columns, grids, or any other suitable arrangement with any suitable magnetic pole pitch. In some embodiments, the corresponding stator can include an appropriate number of phases, with the phases having an appropriate axial phase length based on the magnetic pole pitch. Center axis 1990 is shown for reference. For example, magnet segment 1913 can be symmetrical, nearly symmetrical, or otherwise have symmetry about center axis 1990.

[0093] Fig. 20 A device for arranging magnets ( Fig. 20 A perspective view of a portion of an illustrative translator 2000 having a feature 2004 (not shown in the figure). Feature 2004 is configured to help arrange the magnets of segment 2002. In some embodiments, as shown, feature 2004 includes a raised protrusion that is configured to serve as an index for locating the magnets during assembly, operation, or both. In addition, feature 2004 (e.g., the protrusion) can provide resistance against axial acceleration and help hold the magnets in place. In addition, in some embodiments, the magnets can be bonded to the translator using a suitable adhesive. Features 2004 can be, but need not be, evenly spaced. For example, features 2004 can be spaced axially to accommodate magnets having varying axial lengths (e.g., shorter magnets at the axial ends).

[0094] Fig.21A perspective view of a portion of an illustrative translator segment 2100 arranged with magnets 2104 is shown in accordance with some embodiments of the present disclosure. The translator segment 2100 is shown with magnets 2102 and 2103 removed for clarity (e.g., an operable translator includes magnets attached to a body 2110). The magnets 2104 are arranged in rows 2152 that are arranged at a particular axial position or range of positions and extend azimuthally at least partially around the body 2110, and the magnets 2104 are arranged in stacks 2151 that are arranged at a particular azimuth position or range of positions and extend axially. For example, a row in a row 2152 may extend azimuthally around the body 2110, while a stack in a stack 2151 may extend along the entire or nearly the entire axial length of the body 2110. The magnets 2104 may be arranged in rows 2152 of alternating polarity orientations (e.g., N and S). In some embodiments, all magnets in a row have the same polarity orientation, while magnets along a stack have alternating polarity orientations. In some embodiments, as shown, a coupling 2101 is arranged radially below the magnet 2104 to help attach the magnet 2104 to the body 2110. The body 2110 can be made of any suitable material and can be configured to interface with one or more translator tubes (e.g., having bearing surfaces) to form a translator. For example, the body 2110 can be composed of a metal composite that can reduce eddy current losses in the translator. In some embodiments, the translator tube is composed of a non-ferrous material and the body 2110 is composed of an iron material to complete the magnetic circuit (e.g., in a Hallbach arrangement). In some embodiments, the body 2110 can include a bearing surface (e.g., the body 2110 and the magnet 2204 can form a translator without additional structural components). In some embodiments, the magnet is press-fit into the translator or a section thereof (e.g., radially or axially compressed). For example, the magnets may be arranged inside the translator or a segment thereof (eg, if axially press-fitted or 3D printed) such that there is a layer of material (eg, metal) between the magnets and the stator teeth.

[0095] Fig. 22 A cross-sectional view of a portion of an illustrative magnet segment 2200 is shown in accordance with some embodiments of the present disclosure. In some embodiments, the translator assembly includes one or more end features 2202 to constrain the position / motion of magnet 2210 (e.g., to resist acceleration of the magnet). In some embodiments, the translator assembly includes one or more locating features 2204 to constrain the position / motion of magnets 2211 and 2210 (e.g., to resist acceleration of the magnet). In one illustrative example, Fig. 20The features 2004 may include end features 2202, locating features 2204, or both. In some embodiments, the magnets are bonded to the translator tube (e.g., using an adhesive). Fig.23 As shown, the magnet assembly is wrapped with a material (e.g., a material that complies with thermal expansion) to protect the magnet. In some embodiments, the feature 2004 and the end feature 2202 are machined into a body (e.g., similar to Fig.21 2110) or attached to the body, which is attached to one or more translator tubes (e.g., similar to Fig.16 translator tube 1612 in).

[0096] Fig.23 A perspective view of an illustrative translator 2300 with a wrap 2301 is shown in accordance with some embodiments of the present disclosure. In some embodiments, segment 2302 includes magnets arranged in an array (e.g., extending partially or completely around the translator tube or extending axially along the translator tube). An optional wrap 2301 is included to apply a compressive force to the magnets (e.g., in a radially inward direction), protect the magnets from friction / collision, prevent any magnets from popping out (e.g., in the event of a bond failure), or a combination thereof. In some embodiments, the optional wrap 2301 can accommodate thermal expansion. In some embodiments, the wrap 2301 can include, for example, a Kevlar-based material. For example, in some embodiments, the wrap 2301 is applied by wrapping a sheet of Kevlar material around segment 2302 in one or more layers (e.g., similar to a spool). The wrap can be applied to any suitable segment, for example, Fig.16 Segment 1613 having any suitable axial length along a suitable segment and having any suitable thickness.

[0097] While the design of the stator and magnet segments affects motor efficiency, the bearing design affects the mechanical efficiency of the LEM (e.g., the amount of power lost due to bearing friction and windage during operation). For example, if a streamlined cylindrical oscillator is provided with a moderate peak surface speed, windage losses can be minimized, so mechanical losses tend to be dominated by frictional heating in the bearings supporting the oscillator shaft and the magnet array (e.g., translator). Some illustrative examples of linear contact bearing types include planar dry film bearings, linear ball bearings, and oil-lubricated planar bearings. These solutions typically impose one or more constraints on the system, such as continuous lubrication requirements and / or short maintenance intervals, inability to handle high accelerations or high speeds (e.g., without excessive wear or component damage), short replacement intervals and part life, high friction losses, or a combination thereof. The machines and systems of the present disclosure may include contact bearings, non-contact bearings, or both.

[0098] In some embodiments, the present disclosure describes self-aligning aerostatic bearings (e.g., referred to herein as air bearings or gas bearings). Gas bearings can be used in applications requiring high speeds (e.g., >2 m / s, >5 m / s, >10 m / s, >15 m / s), high mechanical efficiency (e.g., low friction losses), long maintenance intervals, and high durability. Gas bearings work by filling a small gap (e.g., a gap at a bearing interface) with compressed air or other gas through an orifice, a porous media, any other suitable flow restriction, or a combination thereof. As the surface of the translator moves laterally (e.g., radially) closer to a fixed bearing surface (i.e., the air gap decreases), the bearing airflow restriction tightens and the pressure in the bearing gap increases. The pressure provides a restoring force to prevent or limit the situation and severity of the translator surface contacting the bearing surface of the bearing housing. In some embodiments, the gas bearings of the present disclosure consume a moderate amount of compressed gas, and, for example, as long as the feed air is filtered and the bearing does not exceed its load capacity, the gas bearings can have a long operating life even under very high reverse accelerations while minimizing or eliminating friction losses associated with contact bearings or fluid dynamic bearings.

[0099] Fig.24A perspective view of an illustrative bearing housing 2400 according to some embodiments of the present disclosure is shown. As shown, the bearing housing 2400 is configured to extend in azimuth around a translator having a circular bearing surface. In some embodiments, the bearing housing 2400 may include one or more azimuth pieces, radial pieces, or axial pieces that may be assembled to form a complete bearing housing. As shown, the bearing housing 2400 is configured to accommodate a gas bearing and includes a channel 2410 and a flow restrictor 2420. The channel 2410 directs and distributes the bearing gas flow within the bearing housing 2400 to the flow restrictor 2420. The channel 2410 may include, for example, a plenum, a flow channel, a manifold, a filter, a bore, a machine recess, a flow control feature, a port for a sensor (e.g., to sense bearing gas pressure, flow, or temperature), a port for receiving a bearing gas supply, a port for removing condensate (e.g., condensed water, oil, or other condensed fluid), any other suitable feature, or any combination thereof. The flow restrictor 2420 is configured to provide bearing gas to a bearing interface (e.g., a bearing gap) at a bearing hole 2430. The flow restrictor 2420 provides bearing gas to a gas bearing at a desired pressure and flow rate, which provides lateral stiffness for the axis deviation movement of the translator. The flow restrictor 2420 may include, for example, an orifice, a porous section, or both, or any other suitable flow restricting feature. For example, in some embodiments, the flow restrictor 2420 includes an array of orifices along the bearing hole 2430. In some embodiments, the flow restrictor 2420 includes a certain thickness of porous material along the bearing hole 2430. In some embodiments, the bearing housing 2400 may include a coating, a consumable layer, a dry film lubricant, a wear-resistant coating, or a combination thereof at the bearing hole 2430 to accommodate the translator, for example, in contact with the translator.

[0100] Despite Fig.24 The bearing housing 2400 is shown as having a cylindrical bearing hole 2430, but the bearing housing may include any suitable surface for forming a bearing interface. For example, the bearing housing may include a semicircular surface, a flat surface, a non-circular curved surface, a segmented flat or curved surface, any other suitable continuous, segmented or segmented surface, or any combination thereof. For example, the bearing housing may include more than one axially separated cylindrical surface for forming a corresponding bearing interface. In another example, the LEM may include a group of three, four or more bearing housings at a specific axial region, which have flat surfaces and form a corresponding bearing interface together with a corresponding flat surface of a translator (e.g., a translator having a triangular, rectangular or other polygonal cross-section). In some embodiments, the bearing housing does not have to include a channel 2410 or a flow restrictor 2420. For example, the bearing housing can be configured as a contact sliding bearing, wherein a low friction coating is applied at the bearing hole 2430.

[0101] Fig.25 Side and axial views of a portion of an illustrative assembly according to some embodiments of the present disclosure are shown, the assembly including a bearing housing 2502, bearing mounts 2503 and 2505, a flexure 2513, and flexure mounts 2504 and 2506. Flexure 2513 is attached to bearing mounts 2503 and 2505, and also to flexure mounts 2504 and 2506. Flexure mounts 2504 and 2506 are attached to bearing housing 2502. Bearing mounts 2503 and 2505 may be attached to a stator, a frame system (e.g., a frame member or a bulkhead), a cylinder, any other suitable component that is substantially fixed relative to the translator, or any combination thereof. As shown, flexure 2513 is relatively stiff for lateral displacement of bearing housing 2502 (e.g., to maintain lateral alignment) and relatively less stiff for pitch and roll of bearing housing 2502 (e.g., to accommodate disturbances during operation, minor misalignments, or asymmetries of the translator tube). Fig.25 The assembly can allow the translator to continue low friction operation in the event of conditions that may cause the translator or other components to bend (e.g., thermal distortion, force-based distortion).

[0102] The alignment features may include self-aligning flexures (e.g., annular flexures, spherical flexures), joints (e.g., spherical joints, heim joints), or both that allow the bearing housing to self-align with the translator tube (e.g., by pitch, roll, or other non-azimuth rotations), thereby reducing the tolerance accuracy required of components at the bearing interface. In some embodiments, the self-alignment features are integrated into the bearing or are part of the bearing (e.g., a spherical bearing). Flexures are particularly helpful for cylindrical gas bearings because they have small clearances and are relatively incapable of applying torque. It will be understood that the present disclosure does not require that the bearing housing be mounted via self-aligning mounts, and any suitable mounts may be used to connect the bearing housing to a fixed component (e.g., a stator). In some embodiments, the flexures 2513 allow the bearing housing 2502 to self-align with the translator (e.g., to offset asymmetry or deformation of the translator) while keeping the electromagnetic section substantially centered in the stator (e.g., a more uniform motor air gap).

[0103] In some embodiments, the bearing housing (eg, bearing housing 2502) can be arranged so that the magnet segments (eg, Fig.16 At least a portion of the segment 1613) may travel axially beyond the axial length of the stator (e.g., Figure 3 stator 350), exceeding the axial length of the stator hoop stack (e.g., Figure 3, hoop stack 351), or both. For example, the bearing housing can be attached to the stator (e.g., via bearing mounts 2503 and 2505) and a sufficient distance from the stator to allow the magnet segments to travel axially beyond the stator (or the hoop stack therein) so that at least a portion of the magnet segments (and their magnets) do not electromagnetically interact with the stator (or the hoop stack therein). This type of configuration and LEM operation may be advantageous for efficiency, power, cost, manufacturing or maintenance purposes, or any other suitable purpose, or any combination thereof. In some embodiments, the bearing housing can be arranged so that the magnet segments (e.g., Figure 6 At least a portion of the segment 1613) may travel axially no further than the axial length of the stator (e.g., Figure 3 stator 350) of the axial length, not exceeding the axial length of the stator hoop stack (e.g., Figure 3 hoop stack 351), or both.

[0104] Fig.26 Cutaway cross-sectional views of a translator 2600 and a stator 2650 are shown according to some embodiments of the present disclosure. In some embodiments, the stator 2650 may include a protrusion 2604 to accommodate the track 2616 during axial movement of the translator 2600 (e.g., when the track 2616 is axially coincident with the bearing housing 2650). In some embodiments, an air gap between the translator 2600 and the stator 2650 need not be maintained in the protrusion 2604. In some embodiments, the stator includes one or more protrusions to accommodate corresponding features of the translator during axial movement of the translator. For example, while a portion of the stator is configured to form an air gap with the translator (e.g., having a predetermined reluctance and dimensional tolerance with the magnet segment 2601), other portions of the stator need not form an air gap with the translator.

[0105] Fig. 27 2700 and bearing housing 2750 according to some embodiments of the present disclosure. In some embodiments, bearing housing 2750 may include one or more protrusions 2704 to accommodate track 2716 during axial movement of translator 2700 (e.g., when track 2716 axially coincides with or otherwise overlaps bearing housing 2750). Fig. 27 As shown, the gas bearing radially disposed between the bearing housing 2750 and the translator 2700 does not extend into the one or more protrusions 2704. In some embodiments, the gas bearing radially disposed between the bearing housing 2750 and the translator 2700 extends into the one or more protrusions 2704. In some embodiments, the bearing housing 2750 has a clamshell type construction, as shown, where two components are mated together to form a complete bearing housing 2750, such as Fig. 27In some embodiments, the bearing housing may be formed from a single azimuthally continuous housing (e.g., Fig.24 ). It should be noted that, for clarity and ease of illustration, the drawings in this patent application are not necessarily drawn to scale and do not reflect the actual or relative dimensions of each feature. The bearing housing may be any suitable shape, such as circular, rectangular, polygonal, curved, or any other shape including a single segment or more than one segment. Although shown as cylindrical in the present disclosure, the translator "tube" may include any suitable cross-sectional shape or cross-sectional shape profile along its axial length. For example, the translator tube may include an outer surface that serves as a bearing surface, and the bearing surface may be flat, circular, curved, segmented, or any other suitable profile at which a bearing gap may be formed to contain a gas bearing.

[0106] Fig.28 An end view of translator 2800 and additional components is shown in accordance with some embodiments of the present disclosure. Translator 2800 includes a track 2816 that is at least partially rigidly attached to a translator tube of translator 2800. Bearing gaps 2845 and 2846 are disposed between track 2816 and bearing housings 2841 and 2842, respectively. Bearing gaps 2845 and 2846 are configured to be filled with a bearing gas having a pressure suitable for use as a gas bearing to maintain or otherwise constrain the azimuthal position of translator 2800 (e.g., during operation or other processes).

[0107] Bearing housings 2841 and 2842 are configured to interface with corresponding gas bearings, which in turn interface with corresponding surfaces of track 2816. In some embodiments, bearing housings 2841 and 2842 are fixed relative to translator 2800. For example, bearing housings 2841 and 2842 can be rigidly or flexibly mounted to (e.g., fastened to), flexibly mounted to (e.g., mounted to via flexures), or integrated to (e.g., as a single piece with) a stator, a bearing housing for constraining lateral movement of the translator, a frame system, any other suitable fixed component, or any combination thereof. In some embodiments, bearing housings 2841 and 2842 are configured to create corresponding gas bearings that provide azimuthal stiffness for the orientation of translator 2800 (e.g., resist azimuthal rotation of translator 2800, thereby providing azimuthal anti-sync). As shown, supply lines 2871 and 2872 are configured to provide bearing gas (e.g., pressurized bearing gas supplied from a compressor or gas spring at greater than 1 atmosphere) to respective bearing housings 2841 and 2842. In some embodiments, contact bearings may be included instead of or in addition to gas bearings. For example, any or all of bearing housings 2841 and 2842 may alternatively include a bearing surface that is configured to contact track 2816, or otherwise limit azimuthal rotation of track 2816 while allowing track 2816 to slide in an axial direction.

[0108] Position sensor 2840 is configured to sense the relative or absolute position of respective tracks 2815 and 2816 (e.g., and thus sense the position of other features of translator 2800). In some embodiments, translator 2800 is a rigid assembly (e.g., each component moves at substantially the same speed except for vibrations, pressure-induced strains, or other small perturbations). In some embodiments, for example, position sensor 2840 may include an encoder read head (e.g., a magnetic or optical encoder read head), and track 2816 includes a corresponding encoder tape 2817 (e.g., a magnetic or optical tape). In some embodiments, position sensor 2840 may include an encoder read head (e.g., a magnetic or optical encoder read head), and track 2816 includes one or more indexing features to indicate position. In some embodiments, position sensor 2840 is fixed relative to translator 2800, and thus is capable of sensing relative motion of the translator relative to a stator, a cylinder, a bearing housing, any other suitable component, or any combination thereof. For example, position sensor 2840 can be rigidly mounted to (e.g., fastened to), flexibly mounted to (e.g., mounted to via a flexure), or integrated to (e.g., as a single piece with) a stator, a bearing housing, a structural frame system, any other suitable fixed component, or any combination thereof. Position sensor 2840 can include an absolute sensor, a relative sensor, an incremental sensor, any other suitable sensor type for measuring the position of translator 2800, or any combination thereof.

[0109] Fig.29 A cross-sectional view of an illustrative translator 2900 and stator 2970 is shown, in accordance with some embodiments of the present disclosure. Fig.29The cross-sectional view of is taken at an axial position, which shows the translator tube 2902, the magnet assembly 2903 and the stator 2970. The magnet assembly 2903 is coupled to the translator tube 2902 (e.g., using a press fit, fastening, bonding, or any other technique to form a rigid assembly). The stator 2970 may include, for example, phase windings and stator teeth (e.g., laminated sheets of iron or steel). The stator 2970 forms a motor air gap 2972 ​​with the magnet assembly 2903 of the translator 2900 (e.g., the motor air gap 2972 ​​affects the electromagnetic interaction of the stator 2970 and the translator 2900 by changing the magnetic resistance). In some embodiments, the stator 2970 may include an azimuth gap 2971 that continues the axial length of the stator 2970 or a portion thereof, and the magnet assembly 2903 of the translator 2900 may include a corresponding azimuth gap 2901 that continues the axial length of the magnet assembly 2903 or a portion thereof. Gaps in the stator (e.g., gap 2971) and gaps in the magnet assembly (e.g., gap 2901) can be aligned in azimuth and function during operation to maintain the relative azimuth position of the magnetic assembly 2903 and the stator 2970 (e.g., and thereby maintain the relative position of the translator 2900 and the stator 2970). The stator 2970 and the translator 2900 can include any suitable number of corresponding gaps (e.g., the translator can include one or more gaps and the stator can include one or more gaps) that are configured to provide anti-synchronization of the translators. When corresponding gaps of the stator and the translator are misaligned in azimuth, an electromagnetic force is generated that causes the gaps to align. For example, in the event of an azimuth misalignment, a restoring force is generated. In some embodiments, one or more gaps in the stator can allow a phase winding to pass through for routing (e.g., by providing an open path for routing wires away from the phase winding). Although in Fig.292971 and gap 2901 are shown to be approximately equal, but the azimuthal lengths of gap 2971 and gap 2901 do not have to be equal. For example, in some embodiments, gap 2971 and gap 2901 can have different azimuthal lengths, and their corresponding centerline azimuthal positions can be aligned. In some embodiments, the anti-synchronization force between the stator and the translator may be the result of a greater prominence due to intentional gaps in the repetition of the stator lamination pole teeth and the magnet segments of the translator. By changing the gap width between the stator lamination pole teeth, the gap width between the translator poles (magnets), and the thickness of the magnets, these intentional gaps can be used to optimize the force / power density and anti-rotational force. In some embodiments, the stator lamination pole teeth do not include any intentional anti-synchronization gaps. In some embodiments, the anti-synchronization force between the stator and the translator may be the result of a smaller prominence in the magnetic field and reluctance curves due to the segmentation of the stator lamination pole teeth and the magnet array. In some embodiments, anti-synchronization stiffness can be provided by the sum or cumulative effect of all small anti-synchronization forces, each small anti-synchronization force straddling the small physical gap between adjacent stator teeth.

[0110] Fig.30 A cross-sectional view of an illustrative translator 3000 and stator 3070 is shown, in accordance with some embodiments of the present disclosure. Fig.30 The cross-sectional view of is taken at an axial position, which shows the translator tube 3002, the magnets 3003 and 3013, and the stator 3070. The magnets 3003 and 3013 are coupled to the translator tube 3002 (e.g., using a press fit, fastening, bonding, or any other technique to form a rigid assembly). The stator 3070 may include, for example, phase windings (not shown) and stator teeth 3075 and 3076. The stator 3070 forms a motor air gap 3072 with the magnets 3003 and 3013 of the translator 3000 (e.g., the motor air gap 3072 affects the electromagnetic interaction of the stator 3070 and the translator 3030 by changing the magnetic resistance). In some embodiments, stator 3070 may include an azimuth gap 3071 that continues the axial length of stator 3070 or a portion thereof, and translator 3000 may include a corresponding azimuth gap 3001 that continues the axial length of the magnet array or a portion thereof between magnets 3003 and 3013. In some embodiments, azimuth gap 3071 is greater than or equal to azimuth gap 3001. For example, as shown, azimuth gap 3071 is greater than azimuth gap 3001. It should be noted that for clarity and ease of illustration, these drawings are not necessarily drawn to scale.

[0111] Fig.31A block diagram of a LEM according to some embodiments of the present disclosure is shown, including an illustrative motor air gap 3150. Stator 3101 includes stator teeth 3103, windings 3102, and any other suitable components (not shown) according to the present disclosure. Translator 3120 includes a magnet array (e.g., Fig.31 3104). The stator teeth 3103 and the translator 3120 form a motor air gap 3150. When current is applied to the windings 3102 (e.g., as shown by "X" and "O", "X" represents current entering the page, and "O" represents current leaving the page), a magnetic flux is generated (e.g., as shown by flux 3105). The motor air gap 3150 affects the magnetic flux 3105 (e.g., by affecting the reluctance of the magnetic circuit). The windings 3102 can be wound in any suitable orientation and optionally connected in any suitable configuration (e.g., in series in either winding orientation).

[0112] Fig.32 A block diagram of an illustrative motor air gap 3250 with a magnetic pole pitch configuration according to some embodiments of the present disclosure is shown. The stator 3201 includes a slot pitch 3210 and the translator section 3203 includes a magnetic pole pitch 3220. In some embodiments, the slot pitch 3210 and the magnetic pole pitch 3220 can be selected to affect the electromagnetic interaction between the stator 3201 and the translator section 3203. For example, in some embodiments, the slot pitch 3210 and the magnetic pole pitch 3220 can be selected to be unequal to reduce the cogging force. In an illustrative example, the ratio of the magnetic pole pitch 3220 to the slot pitch 3210 can be about 14 / 15. It will be understood that according to the present disclosure, the LEM can include any suitable slot pitch and magnetic pole pitch. In some embodiments, the slot pitch 3201 can vary between hoops based on the position of the hoops within the stator stack. In some embodiments, since the velocity profile of the translator may be highest at the midpoint of travel, a longer slot pitch in the middle of the stator will reduce the phase frequency and the attendant core losses, which increase proportionally with the square of the frequency. Similarly, a shorter stator slot pitch at the ends of the stator will increase the phase frequency or EMF per revolution, in which case the translator moves at a lower speed, thereby allowing greater force / work to be contributed from the end windings. Thus, in some embodiments, hoops located at the end portions of the stator may include a shorter stator slot pitch compared to the stator slot pitch of hoops in the center portion of the stator.

[0113] Fig.33A block diagram of an illustrative LEM system 3300 according to some embodiments of the present disclosure is shown. As shown, the LEM system 3300 includes a control system 3310, power electronics 3320, a cooling system 3321, a sensor 3311, a stator 3350, a translator 3360, bearing housings 3330 and 3331, a bearing gas management system 3380, and a bearing gas supply 3390. The components of the LEM system 3300 are coupled via gap interfaces, signal interfaces, flow interfaces, mechanical interfaces, phase lead interfaces, or combinations thereof. For example, the translator 3360 is coupled to the stator 3350 via a gap interface (e.g., a motor air gap), coupled to the bearing housing 3330 via a gap interface (e.g., a bearing interface such as a gas bearing), and coupled to the bearing housing 3331 via a gap interface (e.g., a bearing interface such as a gas bearing).

[0114] The control system 3310 is configured to interface with the power electronics 3320 (e.g., provide control signals to the power electronics, receive feedback from the power electronics) to control the current in the phases of the stator 3350 (e.g., as in Fig.34 ). The power electronics 3320 is coupled to the stator 3350 via a plurality of phase leads, which may include a length of conductive material, electrical terminals and terminal pieces, connectors, sensors (e.g., current sensors), any other suitable components, or any combination thereof. The control system 3310 is configured to interface with the cooling system 3321 (e.g., provide control signals to the cooling system, receive feedback from the cooling system) to control the cooling of the stator 3350 (e.g., remove heat from windings, stator teeth, hoops, or a combination thereof). For example, the cooling system 3321 may include one or more cooling jackets, plenums, manifolds, pumps, compressors, filters, sensors, any other suitable components, or any combination thereof. In another example, the cooling system 3321 may exchange heat and fluid with a reservoir (e.g., the environment provides cooling air and receives heated air). In another example, the control system 3310 may be communicatively coupled to the cooling system 3321 and configured to provide control signals to the cooling system 3321 to cause heat to be removed from a plurality of windings of the stator 3350. The control system 3310 is configured to interface with (e.g., provide control signals to, receive sensor signals from) sensors 3311, which may include, for example,

[0115] According to the present disclosure, bearing housings 3330 and 3331 may include any suitable number and type of bearing housings. As shown, bearing housings 3330 and 3331 are configured for gas bearings (e.g., using bearing gas management system 3380 and bearing gas supply 3390), although the LEM system may include any suitable type of bearings (e.g., contact or non-contact bearings). In some embodiments, one or more sensors are coupled to each bearing housing 3330 and 3331, which are configured to sense, for example, bearing gas pressure, bearing gas temperature, bearing gas flow rate, bearing housing acceleration (e.g., an accelerometer may be attached to the bearing housing to measure vibration), bearing housing temperature, any other suitable characteristic or behavior, or any combination thereof.

[0116] The bearing gas management system 3380 is configured to control at least one aspect of the respective bearing gases provided to the bearing housings 3330 and 3331. For example, the bearing gas management system 3380 may include one or more filters, compressors, pumps, pressure regulators, valves, sensors, any other suitable components, or any combination thereof, to provide bearing gas to the bearing housings 3330 and 3331. For example, the control system 3310 is configured to interface with the bearing gas management system 3380 (e.g., provide control signals to the bearing gas management system, receive feedback from the bearing gas management system) to control at least one characteristic of the bearing gas. In another example, the control system 3310 is configured to interface with the bearing gas management system 3380 (e.g., provide control signals to the bearing gas management system, receive feedback from the bearing gas management system) to control the stiffness of the bearing interface between the translator 3360 and the bearing housings 3330 and 3331 (e.g., for lateral displacement of the translator 3360). The bearing gas supply 3390 may include one or more filters, compressors, pumps, pressure regulators, valves, sensors, any other suitable components, or any combination thereof, to provide bearing gas to the bearing gas management system 3380. In some embodiments, the bearing gas management system 3380 and the bearing gas supply 3390 may be combined into a single system. In some embodiments, the bearing gas supply 3390 need not be included (e.g., the bearing gas management system 3380 may draw in atmospheric air).

[0117] In some embodiments, the stator 3350 includes a plurality of coils and an axis along which the translator 3360 is arranged to move axially, and the bearing housing 3330, the bearing housing 3331, or both are coupled to the stator 3350 to constrain lateral movement of the translator 3360. For example, the coils include windings that interface with a plurality of stator teeth defining an axis (e.g., an axis of a stator bore). In some such embodiments, the control system 3310 is configured to control axial displacement of the translator and to control lateral displacement of the translator. For example, the bearing housing 3330, the bearing housing 3331, or both form a bearing interface with the translator 3360, and the control system 3310 is configured to control the stiffness of the bearing interface to resist lateral displacement of the translator 3360. In an illustrative example, the bearing interface may include a gas bearing interface configured for oil-free operation (e.g., without the use of a liquid lubricant).

[0118] In some embodiments, the bearing gas management system 3380 is configured to provide pressurized gas to the bearing interface. In some such embodiments, the control system 3310 is communicatively coupled to the bearing gas management system 3380 and is configured to provide a control signal to the bearing gas management system 3380 to cause pressurized gas to be provided to the bearing interface. For example, the control system 3310 can cause the bearing gas management system 3380 to control the characteristics of the pressurized gas to control the lateral stiffness for the lateral displacement of the translator. To illustrate, the bearing gas management system 3380 can provide pressurized gas to the bearing clearance by opening a valve. To further illustrate, the bearing gas management system 3380 can provide pressurized gas by controlling a valve, a pressure regulator, or both.

[0119] In some embodiments, power electronics 3320 is coupled to a plurality of windings of stator 3350. Control system 3310 is communicatively coupled to power electronics 3320 and is configured to provide a control signal to power electronics 3320 to cause current to flow in at least one of the plurality of windings, thereby controlling the axial displacement of translator 3360.

[0120] In some embodiments, the one or more sensors of LEM system 3300 include a position sensor that senses an axial position of translator 3360 relative to stator 3350. In some such embodiments, control system 3310 is communicatively coupled to the sensor (e.g., sensor 3311) and is configured to cause current to flow in a plurality of windings of stator 3350 based on the axial position of translator 3360. In some embodiments, control system 3310 is configured to estimate the axial position of translator 3360 relative to stator 3350 and cause current to flow in a plurality of windings of stator 3350 based on the axial position of translator 3360.

[0121] In some embodiments, the translator 3360 includes at least one track having a track surface (e.g., Figure 16-18 and Fig.28 3300). System 3300 may optionally include at least one anti-sync bearing housing (e.g., bearing housing 3332) coupled to stator 3350 and configured to constrain azimuth motion of translator 3360, wherein anti-sync bearing housing 3332 and the track surface form a track interface. For example, control system 3310 is configured to impart stiffness to the track interface to resist azimuth motion of the translator.

[0122] In some embodiments, the bearing housing 3330 is arranged on the first longitudinal side of the stator 3350 to constrain the lateral movement of the translator 3360 on the first longitudinal side of the stator 3350, and the bearing housing 3331 is arranged on the second longitudinal side of the stator 3350 to constrain the lateral movement of the translator 3360 on the second longitudinal side of the stator 3350.

[0123] In some embodiments, the control system 3310 is configured to control the LEM by causing current to flow in at least one of a plurality of windings of the stator to exert a force on a translator along the longitudinal axis of the stator and to control lateral stiffness for lateral displacement of the translator, wherein the translator is arranged to move along the longitudinal axis of the stator. For example, the translator and the stator can form a motor air gap, and the lateral stiffness provided by the bearing can maintain the motor air gap within an operable range. For example, causing current to flow in at least one winding can include providing a control signal to a power electronic device 3320 electrically coupled to the plurality of windings. In another example,

[0124] In some embodiments, control system 3310 is configured to monitor characteristics of the bearing gas, the bearing housing, or both for a fault condition, and brake the translator in response to identification of a fault condition. For example, control system 3310 may brake the converter by causing power electronics 3320 to apply a current to a phase of stator 3350 that applies a force on translator 3360 that resists the motion of translator 3360 (e.g., thereby reducing the speed of translator 3360, or even stopping it). To illustrate, control system 3310 may monitor the mass flow rate of the bearing gas, the pressure of the bearing gas, the temperature of the bearing gas, the temperature of the bearing housing, the vibration of the bearing housing, the force load on the bearing housing, the translator position trajectory, or a combination thereof.

[0125] Fig.34 A diagram of an illustrative system 3400 according to some embodiments of the present disclosure is shown. System 3400 includes LEM 3440, power electronics system 3430, control system 3450, and auxiliary system 3470. System 3400 may be referred to as a LEM system. It will be appreciated that although Fig.34 3430, but LEM 3440 and power electronics system 3430 may also be integrated or otherwise combined to any suitable extent. For example, in some embodiments, LEM 3440 and power electronics system 3430 may be attached to each other (e.g., directly or indirectly) and coupled via phase leads 3435. In other examples, in some embodiments, power electronics system 3430 may be integrated as part of LEM 3440. In other examples, LEM 3440 may include a stator and translator having multiple phases (e.g., and other suitable components such as cylinders, bearings, piping, etc.) with phase leads 3435, wherein phase leads 3435 are coupled to DC bus 3425 via power electronics system 3430.

[0126] In some embodiments, the LEM 3440 may include one or more translators that can reciprocate relative to the corresponding one or more stators under the combined action of gas pressure and electromagnetic forces. The translators may, but need not, include permanent magnets that can generate back electromotive force (emf) in the phases of the corresponding stators. It will be understood that as used herein and as widely understood, back electromotive force refers to voltage. The power electronics system 3430 is configured to control the current in the phases of the stator of the LEM. For example, the power electronics system 3430 can expose the phase leads of the phases of the stator to one or more buses of a DC bus, a neutral line, a ground line, or a combination thereof.

[0127] The power electronics system 3430 may include, for example, switches (e.g., insulated gate bipolar transistors (IGBTs), metal oxide semiconductor field effect transistors (MOSFETs)), diodes, current sensors, voltage sensors, circuits for managing PWM signals, any other suitable components, or any suitable combination thereof. For example, the power electronics system 3430 may include one or more H-bridges, or other motor control topologies for applying current to switches of one or more phases. In some embodiments, the power electronics system 3430 may interface with the LEM 3440 via phase leads 3435 coupled to the windings of the stator, and the power electronics system 3430 may interface with a grid-connected inverter (not shown) via a DC bus 3425 (e.g., a pair of buses, one bus having a higher voltage relative to the other bus). Bus 3422 and bus 3424 together form a DC bus 3425 in the system 3400. For example, bus 3422 may be nominally 800V relative to 0V of bus 3424 (e.g., bus 322 is "high" and bus 324 is "low"). According to the present disclosure, bus 3422 and bus 3424 can be at any suitable nominal voltage (e.g., >100 VDC, >200 VDC, >400 VDC, >600 VDC, over 800 VDC), which can fluctuate around an average value over time. Thus, the term "DC bus" as used herein shall refer to a pair of buses having a substantially fixed average voltage difference, although the instantaneous voltage may fluctuate, vary, exhibit noise, or otherwise be non-constant.

[0128] Fig.35 is a block diagram of an illustrative phase control system 3500 according to some embodiments of the present disclosure. Fig.35 Illustratively, phase control system 3500 includes: phase controller 3502, power electronics 3504, and power supply 3514. In some embodiments, each phase control system (e.g., similar to phase control system 3500) controls the application of current to a single phase of a multi-phase stator. In addition, each phase control system may include elements of the overall electrical system distributed to each phase control system (e.g., Fig.34 3450, power electronics system 3430, and elements of auxiliary system 3470). In one illustrative example, phase control system 3500 and other phase controllers (e.g., other similar controllers) may be included to control multiple phases of the stator.

[0129] In some embodiments, the phase controller 3502 is configured to control current in one or more phases of the stator. In some embodiments, the desired or commanded current to be applied to the corresponding phase is calculated locally by the phase controller 3502. In some embodiments, the desired or commanded current to be applied to one or more phases is transmitted from a central controller, which determines the current to be applied to each phase (e.g., the phase of the stator and optionally other phases of other stators). For example, the desired or commanded current to be applied to one or more phases can be determined to achieve a measured magnet or translator position, to achieve a total LEM force (e.g., the accumulation of electromagnetic forces applied by each phase), to achieve a translator velocity or acceleration, to achieve a desired translator position (e.g., a vertex position), or any combination thereof.

[0130] In some embodiments, the phase controller 3502 is configured to sense the magnetic flux in the corresponding phase. For example, the phase controller 3502 can sense the magnetic flux of the phase and use the sensed magnetic flux as control feedback. In some such embodiments, the phase controller 3502 does not have to include a current sensor or does not have to be configured to receive input from a current sensor. In addition, in some such embodiments, the phase controller 3502 includes a current sensor with relatively reduced performance, requirements, cost, or a combination thereof.

[0131] In some embodiments, the current applied to each phase or the voltage applied to each phase is controlled locally (i.e., in the case of the phase control system 3500) to any suitable extent. In some embodiments, the phase controller 3502 can perform a local control loop on the phase current. For example, the current command can be transmitted from the central controller to the phase controller 3502 via a communication link. According to the present disclosure, any suitable part of the control mechanism can also be distributed. For example, position measurements can be distributed to each phase, and each phase controller 3502 can determine the desired position and force to determine the current command, which can be applied by the power electronics 3504.

[0132] In some embodiments, phase controller 3502 is configured to provide control signals to power electronics 3504. Power electronics 3504 is configured to be electrically coupled to a phase lead of a phase and to provide current to the phase. Thus, power electronics 3504 includes components configured for amperes and voltages associated with a DC bus and phase leads. For example, power electronics 3504 may include Fig.34The phase controller 3502 need not be configured to electrically manage or interact with such large currents or voltages required by the phase leads and the power electronics 3504. In some embodiments, the phase controller 3502 and the power electronics 3504 may be combined or integrated into a single module that is configured to control current and apply current to the phase. In some embodiments, the power electronics 3504 may be shared between more than one phase. For example, the power electronics 3504 may include multiple power circuits that are configured to receive multiple control signals and are configured to apply current to more than one phase.

[0133] In some embodiments, each phase control system can estimate the position of the translator relative to the stator, rather than a central algorithm estimating or measuring the position. Thus, the central algorithm can be distributed among several phase control systems. In some embodiments, each position estimator for a multi-phase control system can be part of a distributed position estimator. The distributed position estimator can estimate the position based on, for example, sensing of the phase voltage in each corresponding phase. In some such embodiments, it is not necessary to include a dedicated position sensor, thereby saving the cost and reliability issues of the position sensor.

[0134] Power supply 3514 is configured to provide power to components of phase control system 3500 in addition to applying current to the corresponding phase. For example, power supply 3514 can provide power for processing functions of phase controller 3502, diagnostics (e.g., for power electronics 3504), any other suitable process requiring power, or any suitable combination thereof. In some embodiments, each phase control system can include a power supply (e.g., similar to power supply 3514).

[0135] In some embodiments, suitable components of the phase control system 3500 can be coupled to the grid via a coupler 3550. For example, the power electronics 3504 can be coupled to the coupler 3550. In some embodiments, the coupler 3550 can include a cable or bus that transmits AC power (e.g., three-phase 480VAC). In some embodiments, the coupler 3550 can include a cable or bus that transmits DC power (e.g., a DC bus), which can be coupled to the grid, for example, via a grid-tied inverter separate from the phase control system 3500.

[0136] In some embodiments, suitable components of the phase control system 3500 can be connected to one or more phases of the LEM via phase leads 3554. For example, the power electronic device 3504 can be connected to the phase lead 3554. In some embodiments, the phase lead 3554 can include two phase leads per phase corresponding to the phase control system 3500 (for example, three phases and six phase leads correspond to the phase control system 3500 or a full-bridge topology). In some embodiments, the phase lead 3554 can include one phase lead per phase corresponding to the phase control system 3500 (for example, six phase leads of six Y-type connected phases correspond to the phase control system 800 or a half-bridge topology). In some embodiments, the phase leads can be wired in a star configuration. For example, for a Y-type configuration, one phase lead from each phase can be connected together to form a neutral (for example, with a net zero current input or output, so the phase current must sum to zero), and each phase control system applies the controlled phase voltage and therefore the current to the other lead of the corresponding phase. In some such embodiments, only a portion of the DC bus voltage (for example, the difference between the bus and the neutral voltage) can be used to apply to each phase. In some embodiments, the phase leads of each phase can be wired in an independent configuration. For example, the phase control system can include a full H-bridge per phase, and the full DC bus voltage can be applied to the phase in either direction (e.g., to allow the desired current to flow in either direction). This configuration provides a larger voltage range available to each phase and control independence from other phases. For example, in the absence of a common neutral wye connection, the phase currents do not have to sum to zero.

[0137] In some embodiments, suitable components of the phase control system 3500 may be coupled to a communication (COMM) link 3556. For example, the phase controller 3502, the power electronics 3504, the power supply 3514, or a combination thereof may be coupled to the COMM link 3556. In some embodiments, the COMM link 3556 may include a wired communication link, such as an Ethernet cable, a serial circuit, any other suitable wired link, or any combination thereof. In some embodiments, the COMM link 3556 may include a wireless communication link, such as a WiFi transmitter / receiver, a Bluetooth transmitter / receiver, any other suitable wireless link, or any combination thereof. The COMM link 3556 may include any suitable communication link that enables the transmission of data, messages, signals, information, or a combination thereof. In some embodiments, the phase control system 3500 is coupled to a central control system via the communication link 3556. For example, in some embodiments, the phase controller 3502 communicates with the central controller via the COMM link 3556.

[0138] In some embodiments, the phase control system 3500 can be configured to extract power from the corresponding phase of the LEM. For example, in the event of a detected system failure or loss of communication, the phase controller 3502 can attempt to extract energy from the kinetic energy of the translator by commanding current in the opposite direction of the back EMF in the corresponding phase.

[0139] In some embodiments including long stators and short magnet segments (e.g., phases extending spatially beyond the magnet segments), some phases are not used for at least a portion of the magnet travel. For example, when a portion of a magnet segment is not located below a phase (e.g., does not axially overlap at least a portion of the phase), the phase will not electromagnetically interact with the magnet segments in an appreciable manner. The unused phases can be used as inductors, and the phase control system 3500 can be configured to store energy in capacitors or perform power conversion to help regulate the DC bus voltage, bus current, bus power, or a combination thereof. Thus, in addition to exciting electromagnetic forces in the LEM, the phase control system 3500 or its phase controller 3502 can also be used for other purposes.

[0140] In some embodiments, the LEM or its components can be tested, operated, characterized, measured, or otherwise interrogated. For example, the stator can be coupled to the power electronics via the phase leads, and current can be applied to the phases to measure ohmic resistance, measure winding inductance, test short circuits between windings, test thermal response of the stator, test the power electronics, test the control system, or a combination thereof. In another example, the LEM can be coupled to the power electronics via the phase leads, to a cooling system, and to a bearing gas management system. The control system can cause the power electronics to apply current to the phase leads (e.g., to cause the translator to move axially and achieve a desired trajectory), cause the cooling system to provide coolant (e.g., cooling air) to the stator, cause bearing gas to be provided to one or more bearing housings, and cause bearing gas to be provided to one or more anti-sync bearing housings.

[0141] In one illustrative example, a LEM may be included as part of a linear generator (e.g., Fig.36 ). The ability to test the LEM and its components without first installing in, for example, a linear generator or other system can allow for easier maintenance, troubleshooting, and characterization of the LEM without the complexity of additional components of a linear generator. For example, a linear generator can include two LEMs, and it would be advantageous to be able to test either LEM as a standalone unit. In some embodiments, an external energy source provides the force to cause the translator to move (e.g., including a compressor, an electromagnetic source, or other suitable source). In some embodiments, the LEM can operate as a standalone unit that is part of a generator, pump, compressor, or actuator.

[0142] Fig.36A cross-sectional view of an illustrative generator assembly 3600 is shown in accordance with some embodiments of the present disclosure. Generator assembly 3600 is configured as an opposed free piston generator. Generator assembly 3600 includes translators 3610 and 3620 configured to move along axis 3606 (e.g., linearly translate along axis 3606). Translators 3610 and 3620 are configured to move within cylinders 3602, 3604, and 3605, thereby forming expansion and compression volumes 3697, 3698, and 3699 in order to perform boundary work (e.g., determined using an integral ∫PdV over an appropriate range such as stroke or cycle). For clarity, the spatial arrangements of the systems and components described herein will generally be referred to in the context of cylindrical coordinates having axial, radial, and azimuthal directions. It will be understood that any suitable coordinate system may be used in accordance with the present disclosure (e.g., cylindrical coordinates may be mapped to any suitable coordinate system). Note that axis 3606 points in an axial direction, and a radial direction is defined as perpendicular to (e.g., pointing away from) axis 3606. An azimuthal direction is defined as an angular direction about axis 3606 (e.g., orthogonal to axis 3606 and a radial direction, and pointing about axis 3606).

[0143] In some embodiments, the stationary components of the generator assembly 3600 include cylinder 3602, cylinder 3604, cylinder 3605, stator 3618, stator 3628, bearing housing 3616, bearing housing 3617, bearing housing 3626, and bearing housing 3627. In some embodiments, the bearing housings 3616 and 3617 are coupled to the stator 3618 (e.g., directly connected or coupled through an intermediate component such as a flexure, a mount, or both). For example, the bearing housings 3616 and 3617 can be aligned with the stator 3618 (e.g., laterally or axially aligned) and attached to the stator 3618 to maintain a radial air gap between the magnet assembly 3613 and the stator 3618. Similarly, in some embodiments, the bearing housings 3626 and 3627 are rigidly coupled to the stator 3628. In further examples, in some embodiments, the bearing housings 3626 and 3627 are aligned with the stator 3618 but are attached to another portion of the generator assembly or component thereof.

[0144] Translator 3610 includes tube 3612, piston 3611, piston 3614, and magnet assembly 3613, all of which are substantially rigidly coupled to move along axis 3606 as a substantially rigid body relative to a fixed component. Translator 3620 includes tube 3622, piston 3621, piston 3624, and magnet assembly 3623, all of which are substantially rigidly coupled to move along axis 3606 as a substantially rigid body. In some embodiments, magnet assemblies 3613 and 3623 can be a region of tubes 3612 and 3622, respectively. In some embodiments, magnet assemblies 3613 and 3623 can include separate components attached to tubes 3612 and 3622, respectively. Reaction section 3697 is defined by pistons 3611, 3621 and bore 3603 of cylinder 3602. Gas springs 3698 and 3699 are defined by respective pistons 3614 and 3624 and respective cylinders 3604 and 3605. Thus, as translators 3610 and 3620 move along axis 3606, the volumes of reaction section 3697, gas spring 3698, and gas spring 3699 expand and contract. In addition, for example, as the volumes increase or decrease, the pressures within these volumes decrease or increase accordingly. Each of bearing housings 3616, 3617, 3626, and 3627 is configured to provide a gas bearing between itself and a corresponding translator (e.g., tubes 3612 and 3622). For example, each of bearing housings 3616, 3617, 3626, and 3627 can be configured to direct pressurized gas to the gas bearing (e.g., via a flow system). In an illustrative example, each of the bearing housings 3616, 3617, 3626, and 3627 can be configured to direct pressurized gas having an absolute pressure greater than ambient pressure (e.g., 1 atmosphere at sea level) to the gas bearings so that the bearing gas has sufficient pressure to flow through the gas bearings and into the environment (e.g., directly or via other conduits). In some embodiments, the bearing gas can be pressurized relative to the environment (e.g., about 1 atmosphere), the pressure in the breathing system (e.g., the boost pressure, or the gas pressure in the exhaust system (which can be greater than or less than 1 atmosphere)), or any other suitable pressure reference. In some embodiments, the generator assembly 3600 is configured for oil-free operation (e.g., without the use of lubricating liquids or solid-solid contact bearings), wherein the bearing housings 3616, 3617, 3626, and 3627 form gas bearings against the translators 3610 and 3620. Cylinder 3602 includes a hole 3603 that accommodates the compression section 3697. Cylinder 3602 also includes illustrative ports 3619 and 3629 that couple bore 3603 to the exterior of cylinder 3602 to allow for fluid exchange.

[0145] Stator 3618, magnet assembly 3613, tube 3612, and bearing housings 3616 and 3617 form a linear electromagnetic machine (LEM) 3656. Similarly, stator 3628, magnet assembly 3623, tube 3622, and bearing housings 3626 and 3628 form LEM 3652. In addition, the LEM may optionally include one or more pistons attached to the translator. For example, the LEM may be defined as including stator 3618, translator 3610, and bearing housings 3616 and 3617. In another example, the LEM may be defined as including stator 3628, translator 3620, and bearing housings 3626 and 3627. The LEM includes a fixed component (e.g., a stator and a bearing housing) and a translation component (e.g., a translator) that is constrained to move along an axis, wherein the stator is capable of exerting an electromagnetic force on the translator to cause and / or generate motion along the axis. The bearing housing of the LEM may, but need not, be attached to the stator. For example, the bearing housing may be coupled to the stator, the structural frame, the cylinder block, or any combination thereof, directly or through one or more intermediate components. The stators 3618 and 3628 may include a plurality of phase windings forming a plurality of phases. The current in each phase may be controlled by a control system (e.g., which may include corresponding power electronics and processing equipment) to affect the position of the translators 3610 and 3620, the movement of the translators 3610 and 3620, the work interaction with the translators 3610 and 3620, or any combination thereof. In some embodiments, the magnet assemblies 3613 and 3623 include permanent magnets arranged in an array (e.g., with alternating south and north poles). Because the translators 3610 and 3620 move as substantially rigid assemblies, the electromagnetic forces applied to the respective magnet assemblies 3613 and 3623 accelerate and decelerate the translators 3610 and 3620. In some embodiments, the stators 3618 and 3628 can be air cooled (e.g., by an air cooling system), liquid cooled (e.g., by a liquid cooling system), or both. In some embodiments, the stators 3618 and 3628 are arranged around the corresponding translators 3610 and 3620 or their corresponding magnet assemblies 3613 and 3623 (e.g., the motor air gap is arcuate and has a thickness profile). For example, the stators 3618 and 3628 can extend completely around (e.g., 360 degrees azimuthally) or partially around (e.g., having azimuthally arranged segments and azimuthally arranged gaps between the windings of the phases) the corresponding translators 3610 and 3620. In some embodiments, the stators 3618 and 3628 are arranged axially along the corresponding translators 3610 and 3620 or their corresponding magnet assemblies 3613 and 3623. For example, magnet assemblies 3613 and 3623 may include flat magnet segments, and stators 3618 and 3628 may include flat surfaces corresponding to the magnet segments (eg, the motor air gap is planar with a thickness profile).In some embodiments, stators 3618 and 3628 extend axially along respective translators 3610 and 3620 or their respective magnet assemblies 3613 and 3623 .

[0146] It will be understood that the present disclosure is not limited to the embodiments described herein, and can be implemented in the context of any suitable system. In some suitable embodiments, the present disclosure is applicable to reciprocating engines and compressors. In some embodiments, the present disclosure is applicable to free piston engines and compressors. In some embodiments, the present disclosure is applicable to combustion devices and reaction devices, such as reciprocating engines and free piston engines. In some embodiments, the present disclosure is applicable to non-combustion devices and non-reaction devices, such as reciprocating compressors and free piston compressors. In some embodiments, the present disclosure is applicable to linear reciprocating devices (e.g., gas springs) with driver sections. In some embodiments, the present disclosure is applicable to oil-free reciprocating and free piston engines and compressors. In some embodiments, the present disclosure is applicable to oil-free free piston engines with internal or external combustion or reaction. In some embodiments, the present disclosure is applicable to oil-free free piston engines operating with compression ignition (e.g., homogeneous charge compression ignition (HCCI), stratified charge compression ignition (SCCI) or other compression ignition), spark ignition or both. In some embodiments, the present disclosure is applicable to oil-free free piston engines operating with gaseous fuel, liquid fuel or both. In some embodiments, the present disclosure is applicable to linear free piston engines. In some embodiments, the present disclosure is applicable to an engine, which may be a combustion engine with internal combustion / reaction or any type of heat engine with external heat addition (eg, from a heat source or external reaction such as combustion).

[0147] The foregoing is merely an illustration of the principles of the present disclosure, and various modifications may be made by those skilled in the art without departing from the scope of the present disclosure. The above embodiments are presented for illustrative purposes rather than limiting purposes. The present disclosure may also take many forms different from those explicitly described herein. Therefore, it is emphasized that the present disclosure is not limited to the explicitly disclosed methods, systems, and devices, but is intended to include variations and modifications thereof, which are within the spirit of the following claims.

Claims

1. A stator for a linear electromagnetic machine, the stator comprising: A plurality of winding hoops constrained and fixedly aligned, wherein: Each winding hoop of the plurality of winding hoops engages a corresponding set of stator teeth of the plurality of sets of stator teeth, and At least one set of stator teeth in the plurality of sets of stator teeth provides an anti-synchronization force on the translator based on an azimuthal gap between adjacent stator teeth in the at least one set of stator teeth.

2. The stator according to claim 1, wherein: The at least one set of stator teeth includes a plurality of azimuthal gaps between respective adjacent pairs of stator teeth in the at least one set of stator teeth, and wherein the plurality of directional gaps includes the azimuthal gaps.

3. The stator according to claim 2, wherein: The azimuth gap is larger than other gaps in the plurality of azimuth gaps.

4. The stator according to claim 1, wherein: Each stator tooth in the plurality of sets of stator teeth includes a mounting feature to engage a winding hoop in the plurality of winding hoops.

5. The stator according to claim 1, wherein: The plurality of groups of stator teeth are arranged to form a stator bore.

6. The stator according to claim 1, wherein: Each stator tooth in the plurality of sets of stator teeth includes a corresponding slot pitch.

7. The stator according to claim 6, wherein: The slot pitch of each stator tooth is based on the axial position of the corresponding stator tooth.

8. The stator according to claim 6, wherein: The slot pitch of each stator tooth is based on the phase frequency of the respective winding hoop that engages the corresponding set of stator teeth.

9. The stator according to claim 1, wherein: A first tooth in at least one set of stator teeth in the plurality of sets of stator teeth comprises: a first axial feature disposed on a first axial side to engage a second stator tooth of the axially adjacent first set of stator teeth; and A second axial feature is disposed on a second axial side and is configured to engage a third stator tooth of a second axially adjacent set of stator teeth, wherein the second axial side is opposite the first axial side.

10. The stator according to claim 1, wherein: The stator will interact with the translator to provide the anti-synchronization force when the translator moves relative to the stator.

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