CA2936509A1 - Core for transverse flux electrical machine - Google Patents
Core for transverse flux electrical machine Download PDFInfo
- Publication number
- CA2936509A1 CA2936509A1 CA2936509A CA2936509A CA2936509A1 CA 2936509 A1 CA2936509 A1 CA 2936509A1 CA 2936509 A CA2936509 A CA 2936509A CA 2936509 A CA2936509 A CA 2936509A CA 2936509 A1 CA2936509 A1 CA 2936509A1
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- Prior art keywords
- core
- electrical machine
- reduction portion
- transverse flux
- sheet material
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
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Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K21/00—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets
- H02K21/12—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets with stationary armatures and rotating magnets
- H02K21/14—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets with stationary armatures and rotating magnets with magnets rotating within the armatures
- H02K21/145—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets with stationary armatures and rotating magnets with magnets rotating within the armatures having an annular armature coil
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K1/00—Details of the magnetic circuit
- H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
- H02K1/12—Stationary parts of the magnetic circuit
- H02K1/14—Stator cores with salient poles
- H02K1/145—Stator cores with salient poles having an annular coil, e.g. of the claw-pole type
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K2201/00—Specific aspects not provided for in the other groups of this subclass relating to the magnetic circuits
- H02K2201/12—Transversal flux machines
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K2213/00—Specific aspects, not otherwise provided for and not covered by codes H02K2201/00 - H02K2211/00
- H02K2213/03—Machines characterised by numerical values, ranges, mathematical expressions or similar information
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Iron Core Of Rotating Electric Machines (AREA)
Abstract
A transverse flux electrical machine comprising a rotor portion and a stator portion is presented, the stator portion comprising a plurality of cores for use in conjunction with the rotor, each of the plurality of cores comprising a plurality of ferromagnetic sheet material layers substantially bent in a "U" configuration and stacked one on top of the other, a surface of each sheet material layer being substantially parallel with a core axis of the "U" configuration for reducing eddy currents therein and a pair of legs including, respectively, a reduction portion along the legs, toward a pair of poles thereof.
Description
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2
3 BACKGROUND OF THE INVENTION
4 1. Field of the Invention [01] This invention relates generally to transverse flux electrical machines. The 6 present invention more specifically relates to a core for transverse flux alternators 7 and assembly thereof.
9 2. Description of the Related Art [02] Alternators and motors are used in a variety of machines and apparatuses 11 to produce electricity from mechanical movements. They find applications for 12 energy production and transportation, to name a few. Alternators and motors can 13 use Transverse Flux Permanent Magnet (TFPM) technologies.
14 [03] Transverse flux machines with permanent magnet excitation are known from the literature, such as the dissertation by Michael Bork, Entwicklung und 16 Optimierung einer fertigungsgerechten Transversalflugmaschine [Developing and 17 Optimizing a Transverse Flux Machine to Meet Production Requirements], 18 Dissertation 82, RWTH Aachen, Shaker Verlag Aachen, Germany, 1997, pages 19 if. The circularly wound stator winding is surrounded by U-shaped soft iron cores (yokes), which are disposed in the direction of rotation at the spacing of twice the 21 pole pitch. The open ends of these U-shaped cores are aimed at an air gap 22 between the stator and rotor and form the poles of the stator. Facing them, 23 permanent magnets and concentrators are disposed in such a way that the 24 magnets and concentrators that face the poles of a stator core have the opposite polarity. To short-circuit the permanent magnets, which in the rotor rotation are 26 intermittently located between the poles of the stator and have no ferromagnetic 27 short circuit, short-circuit elements are disposed in the stator.
28 [04] Put otherwise, transverse flux electrical machines include a circular stator 29 and a circular rotor, which are separated by an air space called air gap, that allows =
1 a free rotation of the rotor with respect to the stator, and wherein the stator 2 comprises soft iron cores, that direct the magnetic flux in a direction that is mainly 3 perpendicular to the direction of rotation of the rotor. The stator of transverse flux 4 electrical machines also comprises electrical conductors, defining a toroid coil, which is coiled in a direction that is parallel to the direction of rotation of the 6 machine. In this type of machine, the rotor comprises a plurality of identical 7 permanent magnet parts, which are disposed so as to create an alternated 8 magnetic flux in the direction of the air gap. This magnetic flux goes through the air 9 gap with a radial orientation and penetrates the soft iron cores of the stator, which directs this magnetic flux around the electrical conductors.
11 [05] In the transverse flux electrical machine of the type comprising a rotor, 12 which is made of a plurality of identical permanent magnet parts, and of magnetic 13 flux concentrators, the permanent magnets are oriented in such a manner that 14 their magnetization direction is parallel to the direction of rotation of the rotor.
Magnetic flux concentrators are inserted between the permanent magnets and 16 redirect the magnetic flux produced by the permanent magnets, radially towards 17 the air gap.
18 [06] The transverse flux electrical machine includes a stator, which comprises 19 horseshoe-shaped like soft iron cores, which are oriented in such a manner that the magnetic flux that circulates inside these cores, is directed in a direction that is 21 mainly perpendicular to the axis of rotation of the rotor.
22 [07] The perpendicular orientation of the magnetic flux in the cores of the 23 stator, with respect to the rotation direction, gives to transverse flux electrical 24 machines a high ratio of mechanical torque per weight unit of the electrical machine. Eddy currents influence the magnetic efficiency.
26 [08] Eddy currents (also called Foucault currents) are circular electric currents 27 induced within conductors by a changing magnetic field in the conductor, due to 28 Faraday's law of induction. Eddy currents flow in closed loops within conductors, in 29 planes perpendicular to the magnetic field. They can be induced within nearby stationary conductors by a time-varying magnetic field created by an AC
1 electromagnet or transformer, for example, or by relative motion between a 2 magnet and a nearby conductor. The magnitude of the current in a given loop is 3 proportional to the strength of the magnetic field, the area of the loop, and the rate 4 of change of flux, and inversely proportional to the resistivity of the material.
[09] By Lenz law, an eddy current creates a magnetic field that opposes the 6 magnetic field that created it, and thus eddy currents react back on the source of 7 the magnetic field. For example, a nearby conductive surface will exert a drag 8 force on a moving magnet that opposes its motion, due to eddy currents induced 9 in the surface by the moving magnetic field. This effect is employed in eddy current brakes, which are used to stop rotating power tools quickly when they are 11 turned off. The current flowing through the resistance of the conductor also 12 dissipates energy as heat in the material hence having an adverse effect on 13 electrical machines efficiency. Thus eddy currents are a source of energy loss in 14 alternating current (AC) inductors, transformers, electric motors and generators, and other AC machinery, requiring special construction such as laminated 16 magnetic cores to minimize them.
17 [10] Cores made of a stack of sheet material radially laminated and angularly 18 stacked along the coil of the TFEM is channeling the flux therein while producing 19 circular eddy currents in the lamination plane that are not restrained in the thickness of the lamination. The purpose of stacking laminated sheet material is to 21 decrease the eddy current losses, which is not the case when the motor is in the 22 unaligned positon. The coil needs to be more massive to compensate the lower 23 global efficiency of the TFEM by reducing the Joules losses (conducting losses).
24 The cores housing, that is not laminated, is also more complex to manufacture and assemble to hold each core stack together during the assembly of the stator and 26 part of the magnetic flux is loss to the housing when the magnetic concentrators 27 are in the unaligned position. Other detrimental issues are occurring when honing 28 the stator's interior like a separation of the laminated sheets cores.
29 [11] It is therefore desirable to provide a core design that is minimizing eddy currents. It is desirable to produce a core for an electrical machine that is easy to 31 assemble. It is also desirable to provide a core for an electrical machine that is 1 economical to produce. Other deficiencies will become apparent to one skilled in 2 the art to which the invention pertains in view of the following summary and 3 detailed description with its appended figures.
BRIEF DESCRIPTION OF THE DRAWINGS
6 [12] Figure 1 is an isometric view of a TFEM, in accordance with at least one 7 embodiment of the invention;
8 [13] Figure 2 is an isometric view of a TFEM, in accordance with at least one 9 embodiment of the-invention;
[14] Figure 3 an isometric exploded view of a TFEM in accordance with at least 11 one embodiment of the invention;
12 [15] Figure 4 is an isometric view of a prior art core;
13 [16] Figure 5 is an isometric view of an illustration of the magnetic flux of a 14 prior art core;
[17] Figure 6 is an isometric view of an illustration of the Eddy currents flow of 16 a prior art core;
17 [18] Figure 7 is an isometric view of a core, in accordance with at least one 18 embodiment of the invention;
19 [19] Figure 8 is an isometric view of the magnetic flux in a core, in accordance with at least one embodiment of the invention;
21 [20] Figure 9 is an isometric view of the Eddy currents flow in a core, in 22 accordance with at least one embodiment of the invention;
23 [21] Figure 10 is a side elevation view of a core, in accordance with at least 24 one embodiment of the invention;
[22] Figure 11 is an isometric view of a core, in accordance with at least one 26 embodiment of the invention;
1 [23] Figure 12 is an isometric view of a core, in accordance with at least one 2 embodiment of the invention;
3 [24] Figure 13A is an isometric view of a first core manufacturing step, in 4 accordance with at least one embodiment of the invention;
[25] Figure 13B is an isometric view of a second core manufacturing step, in 6 accordance with at least one embodiment of the invention;
7 [26] Figure 130 is an isometric view of a third core manufacturing step, in 8 accordance with at least one embodiment of the invention;
9 [27] Figure 14 is an isometric view of a core, in accordance with at least one embodiment of the invention;
11 [28] Figure 15 is an isometric semi-exploded view of a TFEM phase assembly 12 in accordance with at least one embodiment of the invention;
13 [29] Figure 16 is an isometric semi-exploded view of a TFEM phase assembly, 14 in accordance with at least one embodiment of the invention;
[30] Figure 17 is an isometric semi-exploded view of a TFEM phase assembly, 16 in accordance with at least one embodiment of the invention;
17 [31] Figure 18 is a top plan view of a portion of a TFEM phase assembly, in 18 accordance with at.least one embodiment of the invention;
19 [32] Figure 19 is a top plan view of a portion of a TFEM phase assembly, in accordance with at least one embodiment of the invention;
21 [33] Figure 20 is a side elevation view of a portion of a TFEM phase assembly, 22 in accordance with at least one embodiment of the invention;
23 [34] Figure 21 is an isometric view of a portion of a TFEM phase assembly, in 24 accordance with at least one embodiment of the invention;
[35] Figure 22 is an isometric view of a portion of a TFEM phase assembly, in 26 accordance with at least one embodiment of the invention;
9 2. Description of the Related Art [02] Alternators and motors are used in a variety of machines and apparatuses 11 to produce electricity from mechanical movements. They find applications for 12 energy production and transportation, to name a few. Alternators and motors can 13 use Transverse Flux Permanent Magnet (TFPM) technologies.
14 [03] Transverse flux machines with permanent magnet excitation are known from the literature, such as the dissertation by Michael Bork, Entwicklung und 16 Optimierung einer fertigungsgerechten Transversalflugmaschine [Developing and 17 Optimizing a Transverse Flux Machine to Meet Production Requirements], 18 Dissertation 82, RWTH Aachen, Shaker Verlag Aachen, Germany, 1997, pages 19 if. The circularly wound stator winding is surrounded by U-shaped soft iron cores (yokes), which are disposed in the direction of rotation at the spacing of twice the 21 pole pitch. The open ends of these U-shaped cores are aimed at an air gap 22 between the stator and rotor and form the poles of the stator. Facing them, 23 permanent magnets and concentrators are disposed in such a way that the 24 magnets and concentrators that face the poles of a stator core have the opposite polarity. To short-circuit the permanent magnets, which in the rotor rotation are 26 intermittently located between the poles of the stator and have no ferromagnetic 27 short circuit, short-circuit elements are disposed in the stator.
28 [04] Put otherwise, transverse flux electrical machines include a circular stator 29 and a circular rotor, which are separated by an air space called air gap, that allows =
1 a free rotation of the rotor with respect to the stator, and wherein the stator 2 comprises soft iron cores, that direct the magnetic flux in a direction that is mainly 3 perpendicular to the direction of rotation of the rotor. The stator of transverse flux 4 electrical machines also comprises electrical conductors, defining a toroid coil, which is coiled in a direction that is parallel to the direction of rotation of the 6 machine. In this type of machine, the rotor comprises a plurality of identical 7 permanent magnet parts, which are disposed so as to create an alternated 8 magnetic flux in the direction of the air gap. This magnetic flux goes through the air 9 gap with a radial orientation and penetrates the soft iron cores of the stator, which directs this magnetic flux around the electrical conductors.
11 [05] In the transverse flux electrical machine of the type comprising a rotor, 12 which is made of a plurality of identical permanent magnet parts, and of magnetic 13 flux concentrators, the permanent magnets are oriented in such a manner that 14 their magnetization direction is parallel to the direction of rotation of the rotor.
Magnetic flux concentrators are inserted between the permanent magnets and 16 redirect the magnetic flux produced by the permanent magnets, radially towards 17 the air gap.
18 [06] The transverse flux electrical machine includes a stator, which comprises 19 horseshoe-shaped like soft iron cores, which are oriented in such a manner that the magnetic flux that circulates inside these cores, is directed in a direction that is 21 mainly perpendicular to the axis of rotation of the rotor.
22 [07] The perpendicular orientation of the magnetic flux in the cores of the 23 stator, with respect to the rotation direction, gives to transverse flux electrical 24 machines a high ratio of mechanical torque per weight unit of the electrical machine. Eddy currents influence the magnetic efficiency.
26 [08] Eddy currents (also called Foucault currents) are circular electric currents 27 induced within conductors by a changing magnetic field in the conductor, due to 28 Faraday's law of induction. Eddy currents flow in closed loops within conductors, in 29 planes perpendicular to the magnetic field. They can be induced within nearby stationary conductors by a time-varying magnetic field created by an AC
1 electromagnet or transformer, for example, or by relative motion between a 2 magnet and a nearby conductor. The magnitude of the current in a given loop is 3 proportional to the strength of the magnetic field, the area of the loop, and the rate 4 of change of flux, and inversely proportional to the resistivity of the material.
[09] By Lenz law, an eddy current creates a magnetic field that opposes the 6 magnetic field that created it, and thus eddy currents react back on the source of 7 the magnetic field. For example, a nearby conductive surface will exert a drag 8 force on a moving magnet that opposes its motion, due to eddy currents induced 9 in the surface by the moving magnetic field. This effect is employed in eddy current brakes, which are used to stop rotating power tools quickly when they are 11 turned off. The current flowing through the resistance of the conductor also 12 dissipates energy as heat in the material hence having an adverse effect on 13 electrical machines efficiency. Thus eddy currents are a source of energy loss in 14 alternating current (AC) inductors, transformers, electric motors and generators, and other AC machinery, requiring special construction such as laminated 16 magnetic cores to minimize them.
17 [10] Cores made of a stack of sheet material radially laminated and angularly 18 stacked along the coil of the TFEM is channeling the flux therein while producing 19 circular eddy currents in the lamination plane that are not restrained in the thickness of the lamination. The purpose of stacking laminated sheet material is to 21 decrease the eddy current losses, which is not the case when the motor is in the 22 unaligned positon. The coil needs to be more massive to compensate the lower 23 global efficiency of the TFEM by reducing the Joules losses (conducting losses).
24 The cores housing, that is not laminated, is also more complex to manufacture and assemble to hold each core stack together during the assembly of the stator and 26 part of the magnetic flux is loss to the housing when the magnetic concentrators 27 are in the unaligned position. Other detrimental issues are occurring when honing 28 the stator's interior like a separation of the laminated sheets cores.
29 [11] It is therefore desirable to provide a core design that is minimizing eddy currents. It is desirable to produce a core for an electrical machine that is easy to 31 assemble. It is also desirable to provide a core for an electrical machine that is 1 economical to produce. Other deficiencies will become apparent to one skilled in 2 the art to which the invention pertains in view of the following summary and 3 detailed description with its appended figures.
BRIEF DESCRIPTION OF THE DRAWINGS
6 [12] Figure 1 is an isometric view of a TFEM, in accordance with at least one 7 embodiment of the invention;
8 [13] Figure 2 is an isometric view of a TFEM, in accordance with at least one 9 embodiment of the-invention;
[14] Figure 3 an isometric exploded view of a TFEM in accordance with at least 11 one embodiment of the invention;
12 [15] Figure 4 is an isometric view of a prior art core;
13 [16] Figure 5 is an isometric view of an illustration of the magnetic flux of a 14 prior art core;
[17] Figure 6 is an isometric view of an illustration of the Eddy currents flow of 16 a prior art core;
17 [18] Figure 7 is an isometric view of a core, in accordance with at least one 18 embodiment of the invention;
19 [19] Figure 8 is an isometric view of the magnetic flux in a core, in accordance with at least one embodiment of the invention;
21 [20] Figure 9 is an isometric view of the Eddy currents flow in a core, in 22 accordance with at least one embodiment of the invention;
23 [21] Figure 10 is a side elevation view of a core, in accordance with at least 24 one embodiment of the invention;
[22] Figure 11 is an isometric view of a core, in accordance with at least one 26 embodiment of the invention;
1 [23] Figure 12 is an isometric view of a core, in accordance with at least one 2 embodiment of the invention;
3 [24] Figure 13A is an isometric view of a first core manufacturing step, in 4 accordance with at least one embodiment of the invention;
[25] Figure 13B is an isometric view of a second core manufacturing step, in 6 accordance with at least one embodiment of the invention;
7 [26] Figure 130 is an isometric view of a third core manufacturing step, in 8 accordance with at least one embodiment of the invention;
9 [27] Figure 14 is an isometric view of a core, in accordance with at least one embodiment of the invention;
11 [28] Figure 15 is an isometric semi-exploded view of a TFEM phase assembly 12 in accordance with at least one embodiment of the invention;
13 [29] Figure 16 is an isometric semi-exploded view of a TFEM phase assembly, 14 in accordance with at least one embodiment of the invention;
[30] Figure 17 is an isometric semi-exploded view of a TFEM phase assembly, 16 in accordance with at least one embodiment of the invention;
17 [31] Figure 18 is a top plan view of a portion of a TFEM phase assembly, in 18 accordance with at.least one embodiment of the invention;
19 [32] Figure 19 is a top plan view of a portion of a TFEM phase assembly, in accordance with at least one embodiment of the invention;
21 [33] Figure 20 is a side elevation view of a portion of a TFEM phase assembly, 22 in accordance with at least one embodiment of the invention;
23 [34] Figure 21 is an isometric view of a portion of a TFEM phase assembly, in 24 accordance with at least one embodiment of the invention;
[35] Figure 22 is an isometric view of a portion of a TFEM phase assembly, in 26 accordance with at least one embodiment of the invention;
5 1 [36] Figure 23 is a side elevation view of a portion of a TFEM phase assembly, 2 in accordance with at least one embodiment of the invention; and 3 [37] Figure 24 is a side elevation view of a portion of a TFEM phase assembly, 4 in accordance with at least one embodiment of the invention.
6 SUMMARY OF THE INVENTION
7 [38] It is one aspect of the present invention to alleviate one or more of the
8 shortcomings of background art by addressing one or more of the existing needs
9 in the art.
[39] The following presents a simplified summary of the invention in order to 11 provide a basic understanding of some aspects of the invention. This summary is 12 not an extensive overview of the invention. It is not intended to identify key/critical 13 elements of the invention or to delineate the scope of the invention.
Its sole 14 purpose is to present some concepts of the invention in a simplified form as a prelude to the more detailed description that is presented later.
16 [40] Generally, an object of the present invention provides a core for a 17 Transverse Flux Electrical Machine (TFEM), which can also be more specifically 18, appreciated as Transverse Flux Permanent Magnet Machine (TFPMM) although 19 TFEM is going to be used below to facilitate reading of the text.
[41] An object of the invention, in accordance with at least one embodiment 21 thereof, is generally described as a core structure for a TFEM.
22 [42] Generally, .an object of the invention, in accordance with at least one 23 embodiment thereof, provides a laminated core for assembly in a TFEM that 24 minimizes the eddy current therein.
[43] An object of the invention, in accordance with at least one embodiment 26 thereof, provides a core for a TFEM that is laminated in the direction parallel to the 27 magnetic field when operatively secured in the TFEM; the flux passes through the 28 core poles parallel to the laminations plane orientation of the laminations in the 29 unaligned position.
1 [44] An object of the invention, in accordance with at least one embodiment 2 thereof, provides a.core that is laminated in a direction partially circling the coil 3 when assembled in a TFEM.
4 [45] An object of the invention, in accordance with at least one embodiment thereof, provides a core that is laminated in a direction partially circling the coil 6 when assembled in a TFEM with an angled portion on the core's legs and a pair of 7 poles of a reduced section.
8 [46] An object of the invention, in accordance with at least one embodiment 9 thereof, provides a more efficient laminated core that allows for a smaller coil in the TFEM that requires less copper thereof.
11 [47] An object of the invention, in accordance with at least one embodiment 12 thereof, provides a laminated core that avoids a lamination of independent sheets 13 stack that has to be bent with different radiuses to achieve a symmetrical sheet 14 stack for the two core poles to have a pole pitch separation distance.
[48] One object of the invention, in accordance with at least one embodiment 16 thereof, provides a core made from cold electrical strip rolled around a rectangular 17 tub, then varnished with the mold to prevent the rolled strip to unroll.
The rolled 18 strip is then cut in two symmetrical parts to obtain two cores and each pole of the 19 core is cut to get the required pole pitch shift between the pair of poles.
[49] One object.of the invention, in accordance with at least one embodiment 21 thereof, provides a core for a TFEM that is composed of a laminated steel sheets 22 and maintains a lower operating temperature when in operation in the TFEM.
23 [50] An object of the invention, in accordance with at least one embodiment 24 thereof, provides a core manufactured with a cold electrical steel strip rolled around a spacer of a shape and size adapted to accommodate therein a coil.
26 [51] Another object of the invention, in accordance with at least one 27 embodiment thereof, provides a core for a TFEM that is laminated in a "U"
shape 28 with a plurality of superposed "U" shaped sheet portion.
=
1 [52] An aspect of the invention, in accordance with at least one embodiment 2 thereof, provides a core made of rolled sheet material having non-conductive 3 varnished applied on a surface thereof.
4 [53] One aspect of the invention, in accordance with at least one embodiment thereof, provides a core made of rolled sheet material using non-conductive 6 varnished to secure together the plurality of superposed layers of rolled sheet 7 material.
8 [54] An aspect of the invention, in accordance with at least one embodiment 9 thereof, provides a.core for a TFEM that is laminated in a configuration adapted to contain the eddy currents in the thickness of the steel sheet when operating in the 11 TFEM.
12 [55] One other aspect of the invention, in accordance with at least one 13 embodiment thereof, provides a pair of cores simultaneously manufactured with a 14 unique rolled strip of cold electrical steel cut in two.
[56] One aspect of the invention, in accordance with at least one embodiment 16 thereof, provides core that are etched to prevent conductivity between adjacent 17 layers of steel sheets.
18 [57] One aspect of the invention, in accordance with at least one embodiment 19 thereof, provides a core having reduced sections abutting operatively facing , 20 concentrators when operatively secured in the TFEM.
21 [58] Another aspect of the invention, in accordance with at least one 22 embodiment thereof, provides a core pole pitch shift provided by reduced sections 23 operatively facing corresponding concentrators when operatively secured in the 24 TFEM.
[59] Another aspect of the invention, in accordance with at least one 26 embodiment thereof, provides a core with angled surfaces on each leg to provide 27 a pole pitch shift.
28 [60] An aspect of the invention, in accordance with at least one embodiment 29 thereof, provides a steel sheet laminating direction that is more resistant to =
1 delamination when machining and honing the core sections operatively facing 2 corresponding concentrators when operatively secured in the TFEM.
3 [61] One other aspect of the invention, in accordance with at least one 4 embodiment thereof, provides TFEM halves for receiving, securing and locating cores in their respective operating locations in a TFEM.
6 [62] Another aspect of the invention, in accordance with at least one 7 embodiment thereof, provides an assembly using the shape of the core to radially 8 locate the core in respect with the TFEM's axis of rotation.
9 [63] One aspect of the invention, in accordance with at least one embodiment thereof, provides smaller halves for securing and locating a plurality of cores 11 therein given the lower eddy current generated by the cores.
12 [64] One aspect of the invention, in accordance with at least one embodiment 13 thereof, provides a transverse flux electrical machine comprising a rotor portion 14 and a stator portion, the stator portion comprising a plurality of cores for use in conjunction with the rotor, each of the plurality of cores comprising a plurality of 16 ferromagnetic sheet material layers substantially bent in a "U"
configuration and 17 stacked one on top of the other, a surface of each sheet material layer being 18 substantially parallel with a core axis of the "U" configuration, and a pair of legs 19 including, respectively, a reduction portion along the legs, toward a pair of poles thereof.
21 [65] Embodiments of the present invention each have at least one of the 22 above-mentioned objects and/or aspects, but do not necessarily have all of them.
23 It should be understood that some aspects of the present invention that have 24 resulted from attempting to attain the above-mentioned objects may not satisfy these objects and/or may satisfy other objects not specifically recited herein.
26 [66] Additional and/or alternative features, aspects, and advantages of 27 embodiments of the present invention will become apparent from the following 28 description, the accompanying drawings, and the appended claims.
1 DESCRIPTION OF EMBODIMENT(S) OF THE INVENTION
2 [67] Our work is now described with reference to the Figures. In the following 3 description, for purposes of explanation, numerous specific details are set forth in 4 order to provide a thorough understanding of the present invention by way of embodiment(s). It may be evident, however, that the present invention may be 6 practiced without these specific details. In other instances, when applicable, well-7 known structures and devices are shown in block diagram form in order to 8 facilitate describing the present invention.
9 [68] A TFEM 10 is illustrated in Figure 1 through Figure 3. The TFEM 10 includes a stator portion 14 and a rotor portion 18. The stator portion 14 is adapted 11 to remain fixed while the rotor portion 1, located within the stator portion 14, is 12 adapted to rotate .in respect with the stator portion 14 about rotation axis 22 13 thereof. The illustrated stator portion 14 is equipped with an array of fins 16 14 radially protruding from the housing 26 to help increase the heat exchange between the housing 26 and the environment. The embodiments illustrated below 16 depict a TFEM 10 with an exemplary number of pairs of poles and an exemplary 17 635 mm (25 inches) diameter at the air gap is for illustrative purposes in the 18 context of the invention. The configuration of the illustrated TFEM 10 includes an 19 internal rotor portion 18 and an external stator portion 14. An alternate embodiment could use an external rotor portion 18 instead of an internal rotor 21 portion 18. The number of phases can change in accordance with the specific 22 application, the desired power output, torque and rotational speed could vary 23 without departing from the scope of the present invention.
24 [69] The TFEM.
of the illustrated embodiments includes a housing 26 adapted to receive therein, for example, three phase modules 30. An axial side member 26 is secured to the housing 26 to hold therein the three assembled electrical phase 27 modules 30 inside the housing 26. Each phase module 30 is adapted to 28 individually provide an electrical phase of alternating current. The present 29 embodiment illustrates three phases 30 axially coupled together to provide tri-phased current when the TFEM 10 is rotatably actuated. In the present 1 embodiment, the axial side member 34 is secured to the housing 26 with a series 2 of fasteners (not illustrated) engaging threaded holes 38.
3 [70] The axial side member 34 and the housing 26 are configured to receive 4 and secure thereto a bearing assembly 42. The bearing assemblies 42 rotatably secure and concentrically locate the rotor portion 18 in respect with the stator 6 portion 14. The actual configuration of the embodiment illustrated in Figure 7 throughout Figure 3 allows removal of the rotor portion 18 in one axial direction 46 8 when the axial side member 34 is unsecured from the housing 26. This allows for 9 easy maintenance of the TFEM 10 once installed in its operating configuration.
[71] As it is also possible to appreciate from the embodiment illustrated in 11 Figure 1 throughout Figure 3 a solid drive member 50 of the rotor portion 18 that 12 rotatably engages and extends through the axial side member 34, on one axial 13 side, and rotatably extends through the housing 26 on the opposite axial side. The 14 solid drive member 50 could alternatively be a hollowed drive member in other unillustrated embodiments. The drive member 50 is adapted to transmit rotatable 16 motive power from an external mechanism (not illustrated) to the TFEM 10.
The 17 external mechanism (not illustrated) could, for example, be a windmill rotatable 18 hub (not illustrated) to which the rotor blades (not illustrated) are secured to 19 transmit rotational. motive power to the TFEM 10. The external mechanism expressed above is a non-limitative example and other external mechanisms 21 adapted to transmit rotational motive power to the TFEM 10 are considered to 22 remain within the scope of the present application.
23 [72] Focusing now on Figure 3 that is illustrating a semi-exploded view of the 24 TFEM 10 where a skilled reader can appreciate the rotor portion 18 is axially extracted from the .stator portion 14. The rotor portion 18 is axially extracted from 26 the stator portion 14 by removing the axial side member 34 from the housing 26. It 27 can be appreciated that the rotor portion 18 of the exemplary embodiment has 28 three distinct axial phase modules 30, each providing an electrical phase, adapted 29 to axially align and operatively cooperate with the three phase modules 30 of the exemplified stator portion 14. The rotor portion 18 includes a plurality of alternated =
1 magnets 54 and concentrators 58 that are disposed parallel with the rotation axis 2 22. Pluralities of Cores 62 are held and located between a pair of aluminum 3 support halve members 66 from which a plurality of pairs of poles 118 are radially 4 and proximally extending therefrom.
[73] As indicated above, the rotor portion 18 is adapted to rotate in respect with 6 the stator portion 14. The speed of rotation can differ depending of the intended 7 purpose. Power remains function of the torque and the rotation speed of the rotor 8 portion 18. Therefore, the TFEM is going to produce more power if the TFEM
rotates rapidly as long as its operating temperature remains in the operating range of its different components to prevent any deterioration thereof (e.g. magnet 11 demagnetization or insulating vanish deterioration, to name a few). The axial side 12 member 34 is adapted to be unsecured from the housing 26 for inspection and 13 maintenance. Figure 3 also illustrates that each phase module 30 of the rotor 18 14 uses a sequence of individual alternated permanent magnet 54 and concentrator 58. Strong permanent magnets 54 can be made of Nb-Fe-B as offered by Hitachi 16 Metals Ltd and NEOMAX Co. Ltd. Alternatively, suitable magnets can be obtained 17 by Magnequench Inc. and part of this technology can be appreciated in patents 18 US 5,411,608, US 5,645,651, US 6,183, 572, US 6,478,890, US 6,979,409 and 19 US 7,144,463.
[74] Each phase module 30 is going to be discussed in more details below.
21 However, a positioning mechanism is provided to angularly locate each phase 22 module 30 in respect with its adjacent phase module 30 so that proper phase shift 23 is maintained. Generally, the phase shift is set at 120 electrical to provide 24 standard symmetrical electric current overlapping over a complete 360 electrical cycle. The 120 phase shift allows to, in theory, eliminate harmonics that are not 26 multiples of three (3). The 120 phase shift illustrated herein is a preferred 27 embodiment and is not intended to limit the angular phase shift of the present 28 invention.
29 [75] The illustrative embodiment of Figure 3 includes three (3) phase modules 30. Another possible embodiment includes a multiple of three (3) phase modules =
1 30 mechanically secured together and electrically connected by phase to increase 2 the capacity of the TFEM 10 by simply increasing the axial length of the TFEM 10.
3 Thus, a nine (9) phase modules 30 would be coupled three-by-three for a "triple"
4 three-phased 30 TFEM 10. Another possible embodiment is a one-phase 30 TFEM 10 including only one phase module 30. One other possible embodiment 6 could be a two-phased TFEM 10 electrically coupled together in a one-phase 7 configuration and with a phase shift of 90 electrical in a two-phase 30 8 configuration.
9 [76] The rotor portion 18 includes a cylindrical support frame 70 preferably removably secured to the rotatable drive member 50. As explained above, the 11 cylindrical support frame 70 is sized and designed to accommodate three electrical 12 phases, each provided by a phase module 30 including its alternate series of 13 magnets 54 and concentrators 58 secured thereon. The circular stator portion 14 14 and the circular rotor portion 18 are separated by an air space called "air gap" 74 that allows an interference-free rotation of the rotor portion 18 with respect to the 16 stator portion 14. Generally, the smallest is the air gap 74 the most performance 17 the TFEM is going to provide. The air gap 74 is however limited to avoid any 18 mechanical interference between the stator portion 14 and the rotor portion 18 and 19 is also going to be influenced by manufacturing and assembly tolerances in addition to thermic expansion of the parts when the TFEM 10 is actuated. The 21 stator portion 14 comprises soft iron cores 62 (C-cores) that direct the magnetic 22 flux in a direction that is mainly perpendicular to the direction of rotation of the 23 rotor portion 18. The stator portion 14 of TFEM 10 also comprises in each phase 24 module 30 electrical conductors defining a toroid coil 78 that is coiled in a direction that is parallel to the direction of rotation of the TFEM 10. In this embodiment, the 26 rotor portion 18 comprises a plurality of identical permanent magnets 54, which 27 are disposed so as to create an alternated magnetic flux in the direction of the air 28 gap 74. This magnetic flux goes through the air gap 74 with a radial orientation 29 and penetrates the soft iron cores 62 of the stator portion 14, which directs this magnetic flux around the toroid coil 78.
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1 [77] In the TFEM 10 of the type comprising a rotor portion 18 including a 2 plurality of identical permanent magnets 54 and of magnetic flux concentrators 58, 3 the permanent magnets 54 are oriented in such a manner that their magnetization 4 direction is parallel=to the direction of rotation of the rotor portion 18, along rotation axis 22. Magnetic flux concentrators 58 are disposed between the permanent 6 magnets 54 and redirect the magnetic flux produced by the permanent magnets 7 54 radially towards the air gap 74. In contrast, the stator portion 14 comprises 8 "horseshoe-shaped" soft iron cores 62, which are oriented in such a manner that 9 the magnetic flux that circulates inside these cores 62 is directed in a direction that is mainly perpendicular to the direction of rotation of the rotor portion 18.
The perpendicular orientation of the magnetic flux in the cores 62 of the stator portion 12 14, with respect to the rotation direction, gives to TFEM a high ratio of mechanical 13 torque per weight unit of the electrical machine.
14 [78] Figure 4 illustrates a prior art core 62 manufactured with a plurality of superposed sheets of metal 82 that are bent and separated with insulating layers 16 86. The sheets of metal 82 are stacked in a plane adapted to be parallel with the 17 axis of rotation 22 when the core 62 is operatively assembled in the TFEM.
The 18 magnetic flux 90 exits from the concentrator 58.1 in a direction orthogonal to the 19 surface of the plurality of superposed sheets of metal 82 as illustrated in Figure 5.
The Eddy currents 94 flow in closed loops within the conductors, in planes 21 perpendicular to the magnetic field 90 and perpendicular to the surfaces of the 22 sheets of metal 82. In contrast, Figure 6 further illustrates the Eddy currents 94 in 23 closed loops in a plane perpendicular to the magnetic field 90 and planar with the 24 surfaces of the sheets of metal 82.
[79] A core 62 manufactured with a plurality of superposed bent sheets of 26 metal 82 about core axis 104, separated with insulating layers 86 stacked in a 27 plane perpendicular with the axis of rotation 22 when the core 62 is operatively 28 assembled in the TFEM, is illustrated in Figure 7. Each leg 114 includes a leg 114 29 section reducing portion 120 embodied as an inclined portion 116 that is progressively reducing the section of each of the legs 114 to provide a pair of 31 poles 118 that is smaller than the section of the legs 114. The inclined portion 116 1 is alternated on opposed sides of the legs 114 thus angularly offsetting the poles 2 118 of a same core 62 to allow magnetic interaction with adjacent concentrators 3 58 when operatively assembled with the rotor portion 18. The reducing portion 120 4 can be adjusted to allow even offset, a distanced offset or partial overlap of the legs' poles 118 in respect with corresponding concentrators 58. The inclined 6 portion 116 is embodied beginning on the core's leg 114, after the bent in the core 7 62. Alternatively, the inclined portion 116 could be embodied beginning next to the 8 bent in the core's leg 114. In another non-illustrated embodiment, in order to 9 radially reduce the height of the core 62 and get a more compact core 62, the inclined portion 116 is beginning on the core's leg 114, before the bent in the core 11 62. The inclined portion 116 is illustrated with a rectilinear or planar surface 12 however, a curved surface 120 could alternatively be embodied without departing 13 from the scope of the present invention. Shape variations in the core 62, using the 14 inclined portion 116, can be adjusted to manage the magnetic flux 90 therein. The magnetic flux 90 exits from the concentrator 58.1 to a first leg 114 of the core 62 in 16 a direction orthogonal to the surface of the plurality of superposed sheets of metal 17 82, as illustrated in Figure 8. The magnetic flux 90 exits the same leg 114 from the 18 opposed leg's surface back to the adjacent concentrator 58.2. This magnetic flux 19 90 path occurs when the concentrators 58 are not radially aligned with the cores' 62 legs 114. Otherwise when the concentrators 58 are aligned with the core's 21 legs 114, the magnetic flux 90 enter one leg 114 of the core 62 and exits through 22 the second leg 114 of the core 62. In both positions the magnetic flux 90 path is 23 parallel to each sheet of metal 82 of the core 62. The Eddy currents 94 flow in 24 closed loops within the conductors in planes perpendicular to the magnetic field 90. Figure 9 further illustrates the Eddy currents 94 in closed loops in a plane 26 perpendicular to the magnetic field 90 and perpendicular with the surfaces of the 27 sheets of metal 82. The Eddy currents 94 are contained in the thickness of the 28 sheets of metal 82 hence producing a plurality of reduced Eddy currents 94 and 29 increasing the efficiency of the core 62.
[80] Figure 10, Figure 11 and Figure 12 depict an exemplary core 62 31 manufactured with a plurality of layers of sheets metal 82. From these Figures, 1 one can appreciate the pattern created by the sheets of metal 82 circling around 2 the central opening 98 configured to receive therein the coil 78 (not illustrated in 3 Figure 10, Figure 11 and Figure 12).
4 [81] A possible manufacturing method for producing a core 62 consists in rolling a strip of sheet metal around a central jig that is sized and designed to 6 leave an opening in the center of the rolled strip of metal 102 forming a double-7 core 106. The rolled strip of ferromagnetic metal 102 is exemplified in Figure 13 a) 8 after a first manufacturing step rolling the strip of sheet metal around the central 9 jig. The double-core 106 is then cut in two along its middle plan 110. The result is depicted in Figure 13 b) showing one half of the double core 106 of Figure 13 a) 11 that is becoming a core 62. A third step is performed to the core's legs 114 at an 12 angle a as illustrated in Figure 13 c). The portions of the legs 114 that are cut on 13 opposite sides of the core 62 to form and locate a pair of poles 118 that are axially 14 offset 122, thus not axially aligned. The pair of poles 118 is axially offset 122 to face different concentrators 58 (not illustrated in Figure 13) and allows movement 16 of the magnetic flux 90 (not illustrated in Figure 13) through the core 62.
The 17 cuttings of the core 62 can be used to adjust the polar offset of the pair of poles 18 118 and the stator overlap, if desirable. Cutting the core 62 should be made in 19 such a way that no. metal residue remains between two layers of sheet of metal 82 hence preventing magnetic shortcuts in the core 62. The core 62 can be etched 21 (etching process) as part of the manufacturing process to ensure no shortcuts are 22 present in the core 62. As mentioned above, a layer of dielectric material, such as 23 electrically insulating resin or varnish, on the faces of the sheets of metal 82 are 24 preventing shortcuts therebetween. An example of a core 62 in its final configuration is depicted in Figure 14. The cores 62 could be further cut to reduce 26 their width and/or their length to build a more compact TFEM. The strip of sheet 27 metal could be stretched, beyond its elastic deformation domain, to change its 28 thickness in specific region of the core 62. Thickness variations of the sheet metal 29 of the layers of the core 62 can be used to modify, alter and/or adjust the magnetic behavior of the cores 62.
1 [82] A
circular array of cores 62 is illustrated in Figure 14, Figure 15 and Figure 2 16 in a predetermined angular array about the axis of rotation 22. The respective 3 positions of each core 62 is determined by corresponding core-receivers 126 4 disposed in each of the pair of support halve members 66.1 and 66.2. The cores 62 are radially located and secured and their pairs of poles 118 are substantially 6 facing the axis of rotation 22. The toroid coil 78 is assembled in the central 7 openings 98 of the cores 62 and connection wires 130 are extending outside the 8 illustrated assembly to be electrically connected. It can be appreciated the cores 9 62 are held by the pair of support halve members 66.1 and 66.2 at an angle thereof, hence providing progressive interaction with the concentrators 58 when 11 operatively assembled with the rotor portion 18 and rotating about the axis of 12 rotation 22.
13 [83] The angle a and angle 13 are illustrated with more details in Figure 17 14 throughout Figure 19. Again, the angle a is dictated by the cut section on each leg of the core 62 while the angle [3 is defined by the shape of the core receivers 126 located in the pair of support halve members 66.1 and 66.2. The core receiver 17 comprises an angled portion 134 adapted to match the corresponding angled 18 portion 138 in each of the legs 114 of the core 62. The angled portion 134 of the 19 core receiver 126 and the corresponding angled portion 138 of the legs 114 are fixing the radial distance of each core 62 in respect with the axis of rotation 22.
21 The final distance of the pair of poles 118 in respect with the rotor portion 18 is 22 going to be determined by the final adjustment of the air gap 74, which could be 23 made by honing the central portion of the assembled stator 14 with a boring machine tool. Figure 20 throughout Figure 23 show a partial assembly of a core with the toroid coil 78 and in cooperation with a set of magnets 54 and concentrators 58. One can appreciate with the partial assembly of the core 62 that 27 the pair of poles 118 is not simultaneously facing a same concentrator 58 because 28 of the opposite cuts with angle a. The angle 13 ensures a progressive interaction 29 between the pair of poles 118 and the concentrators 58.
[84] The description and the drawings that are presented above are meant to 31 be illustrative of the present invention. They are not meant to be limiting of the =
1 scope of the present invention. Modifications to the embodiments described may 2 be made without departing from the present invention, the scope of which is 3 defined by the following claims:
=
[39] The following presents a simplified summary of the invention in order to 11 provide a basic understanding of some aspects of the invention. This summary is 12 not an extensive overview of the invention. It is not intended to identify key/critical 13 elements of the invention or to delineate the scope of the invention.
Its sole 14 purpose is to present some concepts of the invention in a simplified form as a prelude to the more detailed description that is presented later.
16 [40] Generally, an object of the present invention provides a core for a 17 Transverse Flux Electrical Machine (TFEM), which can also be more specifically 18, appreciated as Transverse Flux Permanent Magnet Machine (TFPMM) although 19 TFEM is going to be used below to facilitate reading of the text.
[41] An object of the invention, in accordance with at least one embodiment 21 thereof, is generally described as a core structure for a TFEM.
22 [42] Generally, .an object of the invention, in accordance with at least one 23 embodiment thereof, provides a laminated core for assembly in a TFEM that 24 minimizes the eddy current therein.
[43] An object of the invention, in accordance with at least one embodiment 26 thereof, provides a core for a TFEM that is laminated in the direction parallel to the 27 magnetic field when operatively secured in the TFEM; the flux passes through the 28 core poles parallel to the laminations plane orientation of the laminations in the 29 unaligned position.
1 [44] An object of the invention, in accordance with at least one embodiment 2 thereof, provides a.core that is laminated in a direction partially circling the coil 3 when assembled in a TFEM.
4 [45] An object of the invention, in accordance with at least one embodiment thereof, provides a core that is laminated in a direction partially circling the coil 6 when assembled in a TFEM with an angled portion on the core's legs and a pair of 7 poles of a reduced section.
8 [46] An object of the invention, in accordance with at least one embodiment 9 thereof, provides a more efficient laminated core that allows for a smaller coil in the TFEM that requires less copper thereof.
11 [47] An object of the invention, in accordance with at least one embodiment 12 thereof, provides a laminated core that avoids a lamination of independent sheets 13 stack that has to be bent with different radiuses to achieve a symmetrical sheet 14 stack for the two core poles to have a pole pitch separation distance.
[48] One object of the invention, in accordance with at least one embodiment 16 thereof, provides a core made from cold electrical strip rolled around a rectangular 17 tub, then varnished with the mold to prevent the rolled strip to unroll.
The rolled 18 strip is then cut in two symmetrical parts to obtain two cores and each pole of the 19 core is cut to get the required pole pitch shift between the pair of poles.
[49] One object.of the invention, in accordance with at least one embodiment 21 thereof, provides a core for a TFEM that is composed of a laminated steel sheets 22 and maintains a lower operating temperature when in operation in the TFEM.
23 [50] An object of the invention, in accordance with at least one embodiment 24 thereof, provides a core manufactured with a cold electrical steel strip rolled around a spacer of a shape and size adapted to accommodate therein a coil.
26 [51] Another object of the invention, in accordance with at least one 27 embodiment thereof, provides a core for a TFEM that is laminated in a "U"
shape 28 with a plurality of superposed "U" shaped sheet portion.
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1 [52] An aspect of the invention, in accordance with at least one embodiment 2 thereof, provides a core made of rolled sheet material having non-conductive 3 varnished applied on a surface thereof.
4 [53] One aspect of the invention, in accordance with at least one embodiment thereof, provides a core made of rolled sheet material using non-conductive 6 varnished to secure together the plurality of superposed layers of rolled sheet 7 material.
8 [54] An aspect of the invention, in accordance with at least one embodiment 9 thereof, provides a.core for a TFEM that is laminated in a configuration adapted to contain the eddy currents in the thickness of the steel sheet when operating in the 11 TFEM.
12 [55] One other aspect of the invention, in accordance with at least one 13 embodiment thereof, provides a pair of cores simultaneously manufactured with a 14 unique rolled strip of cold electrical steel cut in two.
[56] One aspect of the invention, in accordance with at least one embodiment 16 thereof, provides core that are etched to prevent conductivity between adjacent 17 layers of steel sheets.
18 [57] One aspect of the invention, in accordance with at least one embodiment 19 thereof, provides a core having reduced sections abutting operatively facing , 20 concentrators when operatively secured in the TFEM.
21 [58] Another aspect of the invention, in accordance with at least one 22 embodiment thereof, provides a core pole pitch shift provided by reduced sections 23 operatively facing corresponding concentrators when operatively secured in the 24 TFEM.
[59] Another aspect of the invention, in accordance with at least one 26 embodiment thereof, provides a core with angled surfaces on each leg to provide 27 a pole pitch shift.
28 [60] An aspect of the invention, in accordance with at least one embodiment 29 thereof, provides a steel sheet laminating direction that is more resistant to =
1 delamination when machining and honing the core sections operatively facing 2 corresponding concentrators when operatively secured in the TFEM.
3 [61] One other aspect of the invention, in accordance with at least one 4 embodiment thereof, provides TFEM halves for receiving, securing and locating cores in their respective operating locations in a TFEM.
6 [62] Another aspect of the invention, in accordance with at least one 7 embodiment thereof, provides an assembly using the shape of the core to radially 8 locate the core in respect with the TFEM's axis of rotation.
9 [63] One aspect of the invention, in accordance with at least one embodiment thereof, provides smaller halves for securing and locating a plurality of cores 11 therein given the lower eddy current generated by the cores.
12 [64] One aspect of the invention, in accordance with at least one embodiment 13 thereof, provides a transverse flux electrical machine comprising a rotor portion 14 and a stator portion, the stator portion comprising a plurality of cores for use in conjunction with the rotor, each of the plurality of cores comprising a plurality of 16 ferromagnetic sheet material layers substantially bent in a "U"
configuration and 17 stacked one on top of the other, a surface of each sheet material layer being 18 substantially parallel with a core axis of the "U" configuration, and a pair of legs 19 including, respectively, a reduction portion along the legs, toward a pair of poles thereof.
21 [65] Embodiments of the present invention each have at least one of the 22 above-mentioned objects and/or aspects, but do not necessarily have all of them.
23 It should be understood that some aspects of the present invention that have 24 resulted from attempting to attain the above-mentioned objects may not satisfy these objects and/or may satisfy other objects not specifically recited herein.
26 [66] Additional and/or alternative features, aspects, and advantages of 27 embodiments of the present invention will become apparent from the following 28 description, the accompanying drawings, and the appended claims.
1 DESCRIPTION OF EMBODIMENT(S) OF THE INVENTION
2 [67] Our work is now described with reference to the Figures. In the following 3 description, for purposes of explanation, numerous specific details are set forth in 4 order to provide a thorough understanding of the present invention by way of embodiment(s). It may be evident, however, that the present invention may be 6 practiced without these specific details. In other instances, when applicable, well-7 known structures and devices are shown in block diagram form in order to 8 facilitate describing the present invention.
9 [68] A TFEM 10 is illustrated in Figure 1 through Figure 3. The TFEM 10 includes a stator portion 14 and a rotor portion 18. The stator portion 14 is adapted 11 to remain fixed while the rotor portion 1, located within the stator portion 14, is 12 adapted to rotate .in respect with the stator portion 14 about rotation axis 22 13 thereof. The illustrated stator portion 14 is equipped with an array of fins 16 14 radially protruding from the housing 26 to help increase the heat exchange between the housing 26 and the environment. The embodiments illustrated below 16 depict a TFEM 10 with an exemplary number of pairs of poles and an exemplary 17 635 mm (25 inches) diameter at the air gap is for illustrative purposes in the 18 context of the invention. The configuration of the illustrated TFEM 10 includes an 19 internal rotor portion 18 and an external stator portion 14. An alternate embodiment could use an external rotor portion 18 instead of an internal rotor 21 portion 18. The number of phases can change in accordance with the specific 22 application, the desired power output, torque and rotational speed could vary 23 without departing from the scope of the present invention.
24 [69] The TFEM.
of the illustrated embodiments includes a housing 26 adapted to receive therein, for example, three phase modules 30. An axial side member 26 is secured to the housing 26 to hold therein the three assembled electrical phase 27 modules 30 inside the housing 26. Each phase module 30 is adapted to 28 individually provide an electrical phase of alternating current. The present 29 embodiment illustrates three phases 30 axially coupled together to provide tri-phased current when the TFEM 10 is rotatably actuated. In the present 1 embodiment, the axial side member 34 is secured to the housing 26 with a series 2 of fasteners (not illustrated) engaging threaded holes 38.
3 [70] The axial side member 34 and the housing 26 are configured to receive 4 and secure thereto a bearing assembly 42. The bearing assemblies 42 rotatably secure and concentrically locate the rotor portion 18 in respect with the stator 6 portion 14. The actual configuration of the embodiment illustrated in Figure 7 throughout Figure 3 allows removal of the rotor portion 18 in one axial direction 46 8 when the axial side member 34 is unsecured from the housing 26. This allows for 9 easy maintenance of the TFEM 10 once installed in its operating configuration.
[71] As it is also possible to appreciate from the embodiment illustrated in 11 Figure 1 throughout Figure 3 a solid drive member 50 of the rotor portion 18 that 12 rotatably engages and extends through the axial side member 34, on one axial 13 side, and rotatably extends through the housing 26 on the opposite axial side. The 14 solid drive member 50 could alternatively be a hollowed drive member in other unillustrated embodiments. The drive member 50 is adapted to transmit rotatable 16 motive power from an external mechanism (not illustrated) to the TFEM 10.
The 17 external mechanism (not illustrated) could, for example, be a windmill rotatable 18 hub (not illustrated) to which the rotor blades (not illustrated) are secured to 19 transmit rotational. motive power to the TFEM 10. The external mechanism expressed above is a non-limitative example and other external mechanisms 21 adapted to transmit rotational motive power to the TFEM 10 are considered to 22 remain within the scope of the present application.
23 [72] Focusing now on Figure 3 that is illustrating a semi-exploded view of the 24 TFEM 10 where a skilled reader can appreciate the rotor portion 18 is axially extracted from the .stator portion 14. The rotor portion 18 is axially extracted from 26 the stator portion 14 by removing the axial side member 34 from the housing 26. It 27 can be appreciated that the rotor portion 18 of the exemplary embodiment has 28 three distinct axial phase modules 30, each providing an electrical phase, adapted 29 to axially align and operatively cooperate with the three phase modules 30 of the exemplified stator portion 14. The rotor portion 18 includes a plurality of alternated =
1 magnets 54 and concentrators 58 that are disposed parallel with the rotation axis 2 22. Pluralities of Cores 62 are held and located between a pair of aluminum 3 support halve members 66 from which a plurality of pairs of poles 118 are radially 4 and proximally extending therefrom.
[73] As indicated above, the rotor portion 18 is adapted to rotate in respect with 6 the stator portion 14. The speed of rotation can differ depending of the intended 7 purpose. Power remains function of the torque and the rotation speed of the rotor 8 portion 18. Therefore, the TFEM is going to produce more power if the TFEM
rotates rapidly as long as its operating temperature remains in the operating range of its different components to prevent any deterioration thereof (e.g. magnet 11 demagnetization or insulating vanish deterioration, to name a few). The axial side 12 member 34 is adapted to be unsecured from the housing 26 for inspection and 13 maintenance. Figure 3 also illustrates that each phase module 30 of the rotor 18 14 uses a sequence of individual alternated permanent magnet 54 and concentrator 58. Strong permanent magnets 54 can be made of Nb-Fe-B as offered by Hitachi 16 Metals Ltd and NEOMAX Co. Ltd. Alternatively, suitable magnets can be obtained 17 by Magnequench Inc. and part of this technology can be appreciated in patents 18 US 5,411,608, US 5,645,651, US 6,183, 572, US 6,478,890, US 6,979,409 and 19 US 7,144,463.
[74] Each phase module 30 is going to be discussed in more details below.
21 However, a positioning mechanism is provided to angularly locate each phase 22 module 30 in respect with its adjacent phase module 30 so that proper phase shift 23 is maintained. Generally, the phase shift is set at 120 electrical to provide 24 standard symmetrical electric current overlapping over a complete 360 electrical cycle. The 120 phase shift allows to, in theory, eliminate harmonics that are not 26 multiples of three (3). The 120 phase shift illustrated herein is a preferred 27 embodiment and is not intended to limit the angular phase shift of the present 28 invention.
29 [75] The illustrative embodiment of Figure 3 includes three (3) phase modules 30. Another possible embodiment includes a multiple of three (3) phase modules =
1 30 mechanically secured together and electrically connected by phase to increase 2 the capacity of the TFEM 10 by simply increasing the axial length of the TFEM 10.
3 Thus, a nine (9) phase modules 30 would be coupled three-by-three for a "triple"
4 three-phased 30 TFEM 10. Another possible embodiment is a one-phase 30 TFEM 10 including only one phase module 30. One other possible embodiment 6 could be a two-phased TFEM 10 electrically coupled together in a one-phase 7 configuration and with a phase shift of 90 electrical in a two-phase 30 8 configuration.
9 [76] The rotor portion 18 includes a cylindrical support frame 70 preferably removably secured to the rotatable drive member 50. As explained above, the 11 cylindrical support frame 70 is sized and designed to accommodate three electrical 12 phases, each provided by a phase module 30 including its alternate series of 13 magnets 54 and concentrators 58 secured thereon. The circular stator portion 14 14 and the circular rotor portion 18 are separated by an air space called "air gap" 74 that allows an interference-free rotation of the rotor portion 18 with respect to the 16 stator portion 14. Generally, the smallest is the air gap 74 the most performance 17 the TFEM is going to provide. The air gap 74 is however limited to avoid any 18 mechanical interference between the stator portion 14 and the rotor portion 18 and 19 is also going to be influenced by manufacturing and assembly tolerances in addition to thermic expansion of the parts when the TFEM 10 is actuated. The 21 stator portion 14 comprises soft iron cores 62 (C-cores) that direct the magnetic 22 flux in a direction that is mainly perpendicular to the direction of rotation of the 23 rotor portion 18. The stator portion 14 of TFEM 10 also comprises in each phase 24 module 30 electrical conductors defining a toroid coil 78 that is coiled in a direction that is parallel to the direction of rotation of the TFEM 10. In this embodiment, the 26 rotor portion 18 comprises a plurality of identical permanent magnets 54, which 27 are disposed so as to create an alternated magnetic flux in the direction of the air 28 gap 74. This magnetic flux goes through the air gap 74 with a radial orientation 29 and penetrates the soft iron cores 62 of the stator portion 14, which directs this magnetic flux around the toroid coil 78.
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1 [77] In the TFEM 10 of the type comprising a rotor portion 18 including a 2 plurality of identical permanent magnets 54 and of magnetic flux concentrators 58, 3 the permanent magnets 54 are oriented in such a manner that their magnetization 4 direction is parallel=to the direction of rotation of the rotor portion 18, along rotation axis 22. Magnetic flux concentrators 58 are disposed between the permanent 6 magnets 54 and redirect the magnetic flux produced by the permanent magnets 7 54 radially towards the air gap 74. In contrast, the stator portion 14 comprises 8 "horseshoe-shaped" soft iron cores 62, which are oriented in such a manner that 9 the magnetic flux that circulates inside these cores 62 is directed in a direction that is mainly perpendicular to the direction of rotation of the rotor portion 18.
The perpendicular orientation of the magnetic flux in the cores 62 of the stator portion 12 14, with respect to the rotation direction, gives to TFEM a high ratio of mechanical 13 torque per weight unit of the electrical machine.
14 [78] Figure 4 illustrates a prior art core 62 manufactured with a plurality of superposed sheets of metal 82 that are bent and separated with insulating layers 16 86. The sheets of metal 82 are stacked in a plane adapted to be parallel with the 17 axis of rotation 22 when the core 62 is operatively assembled in the TFEM.
The 18 magnetic flux 90 exits from the concentrator 58.1 in a direction orthogonal to the 19 surface of the plurality of superposed sheets of metal 82 as illustrated in Figure 5.
The Eddy currents 94 flow in closed loops within the conductors, in planes 21 perpendicular to the magnetic field 90 and perpendicular to the surfaces of the 22 sheets of metal 82. In contrast, Figure 6 further illustrates the Eddy currents 94 in 23 closed loops in a plane perpendicular to the magnetic field 90 and planar with the 24 surfaces of the sheets of metal 82.
[79] A core 62 manufactured with a plurality of superposed bent sheets of 26 metal 82 about core axis 104, separated with insulating layers 86 stacked in a 27 plane perpendicular with the axis of rotation 22 when the core 62 is operatively 28 assembled in the TFEM, is illustrated in Figure 7. Each leg 114 includes a leg 114 29 section reducing portion 120 embodied as an inclined portion 116 that is progressively reducing the section of each of the legs 114 to provide a pair of 31 poles 118 that is smaller than the section of the legs 114. The inclined portion 116 1 is alternated on opposed sides of the legs 114 thus angularly offsetting the poles 2 118 of a same core 62 to allow magnetic interaction with adjacent concentrators 3 58 when operatively assembled with the rotor portion 18. The reducing portion 120 4 can be adjusted to allow even offset, a distanced offset or partial overlap of the legs' poles 118 in respect with corresponding concentrators 58. The inclined 6 portion 116 is embodied beginning on the core's leg 114, after the bent in the core 7 62. Alternatively, the inclined portion 116 could be embodied beginning next to the 8 bent in the core's leg 114. In another non-illustrated embodiment, in order to 9 radially reduce the height of the core 62 and get a more compact core 62, the inclined portion 116 is beginning on the core's leg 114, before the bent in the core 11 62. The inclined portion 116 is illustrated with a rectilinear or planar surface 12 however, a curved surface 120 could alternatively be embodied without departing 13 from the scope of the present invention. Shape variations in the core 62, using the 14 inclined portion 116, can be adjusted to manage the magnetic flux 90 therein. The magnetic flux 90 exits from the concentrator 58.1 to a first leg 114 of the core 62 in 16 a direction orthogonal to the surface of the plurality of superposed sheets of metal 17 82, as illustrated in Figure 8. The magnetic flux 90 exits the same leg 114 from the 18 opposed leg's surface back to the adjacent concentrator 58.2. This magnetic flux 19 90 path occurs when the concentrators 58 are not radially aligned with the cores' 62 legs 114. Otherwise when the concentrators 58 are aligned with the core's 21 legs 114, the magnetic flux 90 enter one leg 114 of the core 62 and exits through 22 the second leg 114 of the core 62. In both positions the magnetic flux 90 path is 23 parallel to each sheet of metal 82 of the core 62. The Eddy currents 94 flow in 24 closed loops within the conductors in planes perpendicular to the magnetic field 90. Figure 9 further illustrates the Eddy currents 94 in closed loops in a plane 26 perpendicular to the magnetic field 90 and perpendicular with the surfaces of the 27 sheets of metal 82. The Eddy currents 94 are contained in the thickness of the 28 sheets of metal 82 hence producing a plurality of reduced Eddy currents 94 and 29 increasing the efficiency of the core 62.
[80] Figure 10, Figure 11 and Figure 12 depict an exemplary core 62 31 manufactured with a plurality of layers of sheets metal 82. From these Figures, 1 one can appreciate the pattern created by the sheets of metal 82 circling around 2 the central opening 98 configured to receive therein the coil 78 (not illustrated in 3 Figure 10, Figure 11 and Figure 12).
4 [81] A possible manufacturing method for producing a core 62 consists in rolling a strip of sheet metal around a central jig that is sized and designed to 6 leave an opening in the center of the rolled strip of metal 102 forming a double-7 core 106. The rolled strip of ferromagnetic metal 102 is exemplified in Figure 13 a) 8 after a first manufacturing step rolling the strip of sheet metal around the central 9 jig. The double-core 106 is then cut in two along its middle plan 110. The result is depicted in Figure 13 b) showing one half of the double core 106 of Figure 13 a) 11 that is becoming a core 62. A third step is performed to the core's legs 114 at an 12 angle a as illustrated in Figure 13 c). The portions of the legs 114 that are cut on 13 opposite sides of the core 62 to form and locate a pair of poles 118 that are axially 14 offset 122, thus not axially aligned. The pair of poles 118 is axially offset 122 to face different concentrators 58 (not illustrated in Figure 13) and allows movement 16 of the magnetic flux 90 (not illustrated in Figure 13) through the core 62.
The 17 cuttings of the core 62 can be used to adjust the polar offset of the pair of poles 18 118 and the stator overlap, if desirable. Cutting the core 62 should be made in 19 such a way that no. metal residue remains between two layers of sheet of metal 82 hence preventing magnetic shortcuts in the core 62. The core 62 can be etched 21 (etching process) as part of the manufacturing process to ensure no shortcuts are 22 present in the core 62. As mentioned above, a layer of dielectric material, such as 23 electrically insulating resin or varnish, on the faces of the sheets of metal 82 are 24 preventing shortcuts therebetween. An example of a core 62 in its final configuration is depicted in Figure 14. The cores 62 could be further cut to reduce 26 their width and/or their length to build a more compact TFEM. The strip of sheet 27 metal could be stretched, beyond its elastic deformation domain, to change its 28 thickness in specific region of the core 62. Thickness variations of the sheet metal 29 of the layers of the core 62 can be used to modify, alter and/or adjust the magnetic behavior of the cores 62.
1 [82] A
circular array of cores 62 is illustrated in Figure 14, Figure 15 and Figure 2 16 in a predetermined angular array about the axis of rotation 22. The respective 3 positions of each core 62 is determined by corresponding core-receivers 126 4 disposed in each of the pair of support halve members 66.1 and 66.2. The cores 62 are radially located and secured and their pairs of poles 118 are substantially 6 facing the axis of rotation 22. The toroid coil 78 is assembled in the central 7 openings 98 of the cores 62 and connection wires 130 are extending outside the 8 illustrated assembly to be electrically connected. It can be appreciated the cores 9 62 are held by the pair of support halve members 66.1 and 66.2 at an angle thereof, hence providing progressive interaction with the concentrators 58 when 11 operatively assembled with the rotor portion 18 and rotating about the axis of 12 rotation 22.
13 [83] The angle a and angle 13 are illustrated with more details in Figure 17 14 throughout Figure 19. Again, the angle a is dictated by the cut section on each leg of the core 62 while the angle [3 is defined by the shape of the core receivers 126 located in the pair of support halve members 66.1 and 66.2. The core receiver 17 comprises an angled portion 134 adapted to match the corresponding angled 18 portion 138 in each of the legs 114 of the core 62. The angled portion 134 of the 19 core receiver 126 and the corresponding angled portion 138 of the legs 114 are fixing the radial distance of each core 62 in respect with the axis of rotation 22.
21 The final distance of the pair of poles 118 in respect with the rotor portion 18 is 22 going to be determined by the final adjustment of the air gap 74, which could be 23 made by honing the central portion of the assembled stator 14 with a boring machine tool. Figure 20 throughout Figure 23 show a partial assembly of a core with the toroid coil 78 and in cooperation with a set of magnets 54 and concentrators 58. One can appreciate with the partial assembly of the core 62 that 27 the pair of poles 118 is not simultaneously facing a same concentrator 58 because 28 of the opposite cuts with angle a. The angle 13 ensures a progressive interaction 29 between the pair of poles 118 and the concentrators 58.
[84] The description and the drawings that are presented above are meant to 31 be illustrative of the present invention. They are not meant to be limiting of the =
1 scope of the present invention. Modifications to the embodiments described may 2 be made without departing from the present invention, the scope of which is 3 defined by the following claims:
=
Claims (20)
1. A core for use in conjunction with an electrical machine, the core comprising.
a plurality of ferromagnetic sheet material layers substantially bent in a "U" configuration and stacked one on top of the other, a surface of each sheet material layer being substantially parallel with a core axis of the "U"
configuration; and a pair of legs including, respectively, a reduction portion along the legs, toward a pair of poles thereof.
a plurality of ferromagnetic sheet material layers substantially bent in a "U" configuration and stacked one on top of the other, a surface of each sheet material layer being substantially parallel with a core axis of the "U"
configuration; and a pair of legs including, respectively, a reduction portion along the legs, toward a pair of poles thereof.
2. The core of claim 1, wherein the reduction portion includes an angled planar portion thereof.
3. The core of claim 1, wherein the reduction portion on a first leg of the core is opposed to the reduction portion on a second leg.
4. The core of claim 1, wherein the reduction portion on the first leg of the core opposed to the reduction portion on the second leg to create a poles offset.
5. The core of claim 1, wherein the reduction portion is adjusting a core overlap in respect with corresponding concentrators..
6. The core of claim 1, wherein adjacent sheet material layers are separated with an insulation layer therebetween
7. The core of claim 1, wherein the core includes a pair of adjacent bents partially circumventing the core axis.
8. The core of claim 1, wherein at least one ferromagnetic sheet material layer includes a thickness variation thereof.
9 The core of claim 8, wherein the thickness variation is located at the bent in the ferromagnetic sheet material layer.
The core of claim 1, wherein the reduction portion is adapted to radially locate the core in respect with an axis of rotation of the electrical machine
11 A transverse flux electrical machine comprising a rotor portion, and a stator portion, the stator portion comprising a plurality of cores for use in conjunction with the rotor, each of the plurality of cores comprising a plurality of ferromagnetic sheet material layers substantially bent in a "U" configuration and stacked one on top of the other, a surface of each sheet material layer being substantially parallel with a core axis of the "U"
configuration, and a pair of legs including, respectively, a reduction portion along the legs, toward a pair of poles thereof.
configuration, and a pair of legs including, respectively, a reduction portion along the legs, toward a pair of poles thereof.
12 The transverse flux electrical machine of claim 11, wherein the reduction portion includes an angled planar portion thereof
13. The transverse flux electrical machine of claim 11, wherein the reduction portion on a first leg of the core is opposed to the reduction portion on a second leg.
14. The transverse flux electrical machine of claim 11, wherein the reduction portion on the first leg of the core opposed to the reduction portion on the second leg to create a poles offset.
15. The transverse flux electrical machine of claim 11, wherein the reduction portion is adjusting a core overlap in respect with corresponding concentrators .
16. The transverse flux electrical machine of claim 11, wherein adjacent sheet material layers are separated with an insulation layer therebetween .
17. The transverse flux electrical machine of claim 11, wherein the core includes a pair of adjacent bents partially circumventing the core axis.
18. The transverse flux electrical machine of claim 11, wherein at least one ferromagnetic sheet material layer includes a thickness variation thereof.
19. The transverse flux electrical machine of claim 18, wherein the thickness variation is located at the bent in the ferromagnetic sheet material layer.
20. The transverse flux electrical machine of claim 11, wherein the reduction portion is adapted to radially locate the core in respect with an axis of rotation of the transverse flux electrical machine.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US201662194352P | 2016-07-19 | 2016-07-19 | |
| CA62/194,352 | 2016-07-19 | ||
| US15/214,159 US10355569B2 (en) | 2015-07-20 | 2016-07-19 | Core for transverse flux electrical machine |
| CA15/214,159 | 2016-07-19 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2936509A1 true CA2936509A1 (en) | 2018-01-19 |
Family
ID=60989354
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA2936509A Abandoned CA2936509A1 (en) | 2016-07-19 | 2016-07-19 | Core for transverse flux electrical machine |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2936509A1 (en) |
-
2016
- 2016-07-19 CA CA2936509A patent/CA2936509A1/en not_active Abandoned
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