U.S. patent application number 13/187744 was filed with the patent office on 2011-11-10 for transverse and/or commutated flux system stator concepts.
This patent application is currently assigned to MOTOR EXCELLENCE, LLC. Invention is credited to David G. Calley, Thomas F. Janecek.
Application Number | 20110273035 13/187744 |
Document ID | / |
Family ID | 42130517 |
Filed Date | 2011-11-10 |
United States Patent
Application |
20110273035 |
Kind Code |
A1 |
Calley; David G. ; et
al. |
November 10, 2011 |
TRANSVERSE AND/OR COMMUTATED FLUX SYSTEM STATOR CONCEPTS
Abstract
Disclosed are transverse and/or commutated flux machines and
components thereof, and methods of making and using the same.
Certain exemplary stators for use in transverse and commutated flux
machines may be configured with gaps therebetween, for example in
order to counteract tolerance stackup. Other exemplary stators may
be configured as partial stators having a limited number of magnets
and/or flux concentrators thereon. Partial stators may facilitate
ease of assembly and/or use with various rotors. Additionally,
exemplary floating stators can allow a transverse and/or commutated
flux machine to utilize an air gap independent of the diameter of a
rotor. Via use of such exemplary stators, transverse and/or
commutated flux machines can achieve improved performance,
efficiency, and/or be sized or otherwise configured for various
applications.
Inventors: |
Calley; David G.;
(Flagstaff, AZ) ; Janecek; Thomas F.; (Flagstaff,
AZ) |
Assignee: |
MOTOR EXCELLENCE, LLC
Flagstaff
AZ
|
Family ID: |
42130517 |
Appl. No.: |
13/187744 |
Filed: |
July 21, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12942495 |
Nov 9, 2010 |
8008821 |
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13187744 |
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12611728 |
Nov 3, 2009 |
7851965 |
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12942495 |
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61110874 |
Nov 3, 2008 |
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61110879 |
Nov 3, 2008 |
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61110884 |
Nov 3, 2008 |
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61110889 |
Nov 3, 2008 |
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61114881 |
Nov 14, 2008 |
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61168447 |
Apr 10, 2009 |
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Current U.S.
Class: |
310/46 |
Current CPC
Class: |
H02K 37/02 20130101;
H02K 2201/12 20130101; H02K 41/025 20130101; H02K 2201/15 20130101;
Y10T 29/49012 20150115; H02K 1/246 20130101; H02K 1/04 20130101;
H02K 1/02 20130101 |
Class at
Publication: |
310/46 |
International
Class: |
H02K 37/02 20060101
H02K037/02 |
Claims
1. An electrical machine, comprising: a partial stator assembly
comprising: a flux concentrator; a first magnet connected to a
first side of the flux concentrator; and a second magnet connected
to a second side of the flux concentrator opposite the first side,
wherein the first magnet and the second magnet are magnetically
oriented such that a common magnetic pole is present on the first
and second sides of the flux concentrator; and a conductive coil at
least partially enclosed by the partial stator assembly, wherein
the conductive coil is configured with a single winding
configuration, and wherein the electrical machine is at least one
of a transverse flux machine or a commutated flux machine.
2. The electrical machine of claim 1, wherein the ratio of the
length of the conductive coil to the thickness of the conductive
coil is less than 20:1.
3. The electrical machine of claim 1, wherein the conductive coil
is configured to remove, via conduction, at least 70% of the heat
generated in the conductive coil arising from interaction of the
conductive coil with the partial stator assembly.
4. The electrical machine of claim 1, further comprising an
electronics board coupled to the conductive coil, wherein the
length of the conductive coil from an edge of the partial stator
assembly to an edge of the electronics board is less than two
inches.
5. The electrical machine of claim 1, wherein the conductive coil
is at least partially enclosed by multiple partial stator
assemblies.
6. The electrical machine of claim 1, wherein the conductive coil
comprises a laminated material.
7. The electrical machine of claim 1, further comprising a
multipath rotor coupled to the partial stator assembly.
8. The electrical machine of claim 1, wherein the electrical
machine comprises a plurality of partial stator assemblies and a
plurality of conductive coils such that the electrical machine is a
polyphase device.
9. The electrical machine of claim 1, wherein the partial stator
assembly extends along less than 10% of the circumference of the
electrical machine.
10. A method of manufacturing an electrical machine, the method
comprising: coupling a conductive coil to a partial stator assembly
in a single winding configuration; and coupling a rotor to the
partial stator assembly, wherein the electrical machine is at least
one of a transverse flux machine or a commutated flux machine.
11. The method of claim 10, further comprising coupling an
electronics board to the conductive coil.
12. The method of claim 11, wherein the length of the conductive
coil between the partial stator assembly and the electronics board
is less than 2 inches.
13. The method of claim 10, wherein the rotor is a multipath
rotor.
14. The method of claim 10, wherein coupling the conductive coil to
a partial stator assembly comprises coupling the conductive coil to
a plurality of partial stator assemblies in a single winding
configuration.
15. The method of claim 10, wherein coupling the conductive coil to
a partial stator assembly comprises: coupling a first conductive
coil to a first partial stator assembly in a single winding
configuration; and coupling a second conductive coil to a second
partial stator assembly in a single winding configuration.
16. A method for generating electricity, the method comprising:
coupling an electrical machine to a load, wherein the electrical
machine comprises: a partial stator assembly; a conductive coil
configured with a single winding configuration; and a rotor coupled
to the partial stator assembly, wherein the electrical machine is
at least one of a transverse flux machine or a commutated flux
machine; and rotating the rotor to induce a voltage in the
conductive coil.
17. The method of claim 16, wherein the electrical machine further
comprises an electronics board coupled to the conductive coil, and
wherein the length of the conductive coil between the partial
stator assembly and the electronics board is less than 2
inches.
18. The method of claim 16, wherein the rotor is a multipath
rotor.
19. The method of claim 16, wherein the electrical machine
comprises a plurality of partial stator assemblies, each coupled to
the rotor.
20. The method of claim 16, wherein the rotating the rotor is
responsive to a force applied to the rotor by at least one of: an
engine in a portable generator, a propeller, or a rider of a
bicycle.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. Ser. No.
12/942,495 filed on Nov. 9, 2010, now U.S. Patent Application
Publication No. 2011/0050010 entitled "TRANSVERSE AND/OR COMMUTATED
FLUX SYSTEM STATOR CONCEPTS".
[0002] U.S. Ser. No. 12/942,495 is a divisional of U.S. Ser. No.
12/611,728 filed on Nov. 3, 2009, now U.S. Pat. No. 7,851,965
entitled "TRANSVERSE AND/OR COMMUTATED FLUX SYSTEM STATOR
CONCEPTS".
[0003] U.S. Ser. No. 12/611,728 is a non-provisional of U.S.
Provisional No. 61/110,874 filed on Nov. 3, 2008 and entitled
"ELECTRICAL OUTPUT GENERATING AND DRIVEN ELECTRICAL DEVICES USING
COMMUTATED FLUX AND METHODS OF MAKING AND USE THEREOF INCLUDING
DEVICES WITH TRUNCATED STATOR PORTIONS."
[0004] U.S. Ser. No. 12/611,728 is also a non-provisional of U.S.
Provisional No. 61/110,879 filed on Nov. 3, 2008 and entitled
"ELECTRICAL OUTPUT GENERATING AND DRIVEN ELECTRICAL DEVICES USING
COMMUTATED FLUX AND METHODS OF MAKING AND USE THEREOF."
[0005] U.S. Ser. No. 12/611,728 is also a non-provisional of U.S.
Provisional No. 61/110,884 filed on Nov. 3, 2008 and entitled
"METHODS OF MACHINING AND USING AMORPHOUS METALS OR OTHER
MAGNETICALLY CONDUCTIVE MATERIALS INCLUDING TAPE WOUND TORROID
MATERIAL FOR VARIOUS ELECTROMAGNETIC APPLICATIONS."
[0006] U.S. Ser. No. 12/611,728 is also a non-provisional of U.S.
Provisional No. 61/110,889 filed on Nov. 3, 2008 and entitled
"MULTI-PHASE ELECTRICAL OUTPUT GENERATING AND DRIVEN ELECTRICAL
DEVICES WITH TAPE WOUND CORE LAMINATE ROTOR OR STATOR ELEMENTS, AND
METHODS OF MAKING AND USE THEREOF."
[0007] U.S. Ser. No. 12/611,728 is also a non-provisional of U.S.
Provisional No. 61/114,881 filed on Nov. 14, 2008 and entitled
"ELECTRICAL OUTPUT GENERATING AND DRIVEN ELECTRICAL DEVICES USING
COMMUTATED FLUX AND METHODS OF MAKING AND USE THEREOF."
[0008] U.S. Ser. No. 12/611,728 is also a non-provisional of U.S.
Provisional No. 61/168,447 filed on Apr. 10, 2009 and entitled
"MULTI-PHASE ELECTRICAL OUTPUT GENERATING AND DRIVEN ELECTRICAL
DEVICES, AND METHODS OF MAKING AND USING THE SAME." The entire
contents of all of the foregoing applications are hereby
incorporated by reference.
TECHNICAL FIELD
[0009] The present disclosure relates to electrical systems, and in
particular to transverse flux machines and commutated flux
machines.
BACKGROUND
[0010] Motors and alternators are typically designed for high
efficiency, high power density, and low cost. High power density in
a motor or alternator may be achieved by operating at high
rotational speed and therefore high electrical frequency. However,
many applications require lower rotational speeds. A common
solution to this is to use a gear reduction. Gear reduction reduces
efficiency, adds complexity, adds weight, and adds space
requirements. Additionally, gear reduction increases system costs
and increases mechanical failure rates.
[0011] Additionally, if a high rotational speed is not desired, and
gear reduction is undesirable, then a motor or alternator typically
must have a large number of poles to provide a higher electrical
frequency at a lower rotational speed. However, there is often a
practical limit to the number of poles a particular motor or
alternator can have, for example due to space limitations. Once the
practical limit is reached, in order to achieve a desired power
level the motor or alternator must be relatively large, and thus
have a corresponding lower power density.
[0012] Moreover, existing multipole windings for alternators and
electric motors typically require winding geometry and often
complex winding machines in order to meet size and/or power needs.
As the number of poles increases, the winding problem is typically
made worse. Additionally, as pole count increases, coil losses also
increase (for example, due to resistive effects in the copper wire
or other material comprising the coil). However, greater numbers of
poles have certain advantages, for example allowing a higher
voltage constant per turn, providing higher torque density, and
producing voltage at a higher frequency.
[0013] Most commonly, electric motors are of a radial flux type. To
a far lesser extent, some electric motors are implemented as
transverse flux machines and/or commutated flux machines. It is
desirable to develop improved electric motor and/or alternator
performance and/or configurability. In particular, improved
transverse flux machines and/or commutated flux machines are
desirable.
SUMMARY
[0014] This disclosure relates to transverse and/or commutated flux
machines. In an exemplary embodiment, an electrical machine
comprises a partial stator assembly comprising a flux concentrator,
a first magnet connected to a first side of the flux concentrator,
and a second magnet connected to a second side of the flux
concentrator opposite the first side. The first magnet and the
second magnet are magnetically oriented such that a common magnetic
pole is present on the first and second sides of the flux
concentrator. The electrical machine further comprises a conductive
coil at least partially enclosed by the partial stator assembly.
The conductive coil is configured with a single winding
configuration, and the electrical machine is at least one of a
transverse flux machine or a commutated flux machine.
[0015] In another exemplary embodiment, a method of manufacturing
an electrical machine comprises coupling a conductive coil to a
partial stator assembly in a single winding configuration, and
coupling a rotor to the partial stator assembly. The electrical
machine is at least one of a transverse flux machine or a
commutated flux machine.
[0016] In another exemplary embodiment, a method for generating
electricity comprises coupling an electrical machine to a load. The
electrical machine comprises a partial stator assembly, a
conductive coil configured with a single winding configuration, and
a rotor coupled to the partial stator assembly. The electrical
machine is at least one of a transverse flux machine or a
commutated flux machine. The method further comprises rotating the
rotor to induce a voltage in the conductive coil.
[0017] The contents of this summary section are provided only as a
simplified introduction to the disclosure, and are not intended to
be used to limit the scope of the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] With reference to the following description, appended
claims, and accompanying drawings:
[0019] FIG. 1A illustrates an exemplary transverse flux machine in
accordance with an exemplary embodiment;
[0020] FIG. 1B illustrates an exemplary commutated flux machine in
accordance with an exemplary embodiment;
[0021] FIG. 2A illustrates an exemplary axial gap configuration in
accordance with an exemplary embodiment;
[0022] FIG. 2B illustrates an exemplary radial gap configuration in
accordance with an exemplary embodiment;
[0023] FIG. 3A illustrates an exemplary cavity engaged
configuration in accordance with an exemplary embodiment;
[0024] FIG. 3B illustrates an exemplary face engaged configuration
in accordance with an exemplary embodiment;
[0025] FIG. 3C illustrates an exemplary face engaged axial gap
configuration in accordance with an exemplary embodiment;
[0026] FIG. 4 illustrates various motor performance curves in
accordance with an exemplary embodiment;
[0027] FIG. 5 illustrates, in a cut-away view, an exemplary
transverse flux machine configured for use in a vehicle in
accordance with an exemplary embodiment;
[0028] FIG. 6 illustrates a side perspective view of an exemplary
commutated flux machine section in accordance with an exemplary
embodiment;
[0029] FIG. 7 illustrates a perspective view of an exemplary gapped
stator coupled with an exemplary rotor and coil in accordance with
an exemplary embodiment;
[0030] FIGS. 8A-8C illustrate exemplary partial stators coupled to
a rotor in accordance with an exemplary embodiment;
[0031] FIGS. 9A-9C illustrate exemplary partial stators and
truncated coils coupled to an exemplary electronics board in
accordance with an exemplary embodiment; and
[0032] FIGS. 10A-10B illustrate an exemplary floating stator in
accordance with an exemplary embodiment.
DETAILED DESCRIPTION
[0033] While exemplary embodiments are described herein in
sufficient detail to enable those skilled in the art to practice
the invention, it should be understood that other embodiments may
be realized and that logical electrical, magnetic, and/or
mechanical changes may be made without departing from the spirit
and scope of the present disclosure. Thus, the following
descriptions are not intended as a limitation on the use or
applicability of the present disclosure, but instead, are provided
merely to enable a full and complete description of exemplary
embodiments.
[0034] For the sake of brevity, conventional techniques for
electrical system construction, management, operation, measurement,
optimization, and/or control, as well as conventional techniques
for magnetic flux utilization, concentration, control, and/or
management, may not be described in detail herein. Furthermore, the
connecting lines shown in various figures contained herein are
intended to represent exemplary functional relationships and/or
physical couplings between various elements. It should be noted
that many alternative or additional functional relationships or
physical connections may be present in a practical electrical
system, for example an AC synchronous electric motor.
[0035] Prior electric motors, for example conventional DC brushless
motors, suffer from various deficiencies. For example, many
electric motors are inefficient at various rotational speeds and/or
loads, for example low rotational speeds. Thus, the motor is
typically operated within a narrow RPM range and/or load range of
suitable efficiency. In these configurations, gears or other
mechanical approaches may be required in order to obtain useful
work from the motor.
[0036] Moreover, many electric motors have a low pole count.
Because power is a function of torque and RPM, such motors must
often be operated at a high physical RPM in order to achieve a
desired power density and/or electrical frequency. Moreover, a
higher power density (for example, a higher kilowatt output per
kilogram of active electrical and magnetic motor mass) optionally
is achieved by operating the motor at high rotational speed and
therefore high electrical frequency. However, high electrical
frequency can result in high core losses and hence lower
efficiency. Moreover, high electrical frequency can result in
increased cost, increased mechanical complexity, and/or decreased
reliability. Additionally, high electrical frequency and associated
losses create heat that may require active cooling, and can limit
the operational range of the motor. Heat can also degrade the life
and reliability of a high frequency machine.
[0037] Still other electric motors contain large volumes of copper
wire or other coil material. Due to the length of the coil
windings, resistive effects in the coil lead to coil losses. For
example, such losses convert a portion of electrical energy into
heat, reducing efficiency and potentially leading to thermal damage
to and/or functional destruction of the motor.
[0038] Moreover, many prior electric motors offered low torque
densities. As used herein, "torque density" refers to Newton-meters
produced per kilogram of active electrical and magnetic materials.
For example, many prior electric motors are configured with a
torque density from about 0.5 Newton-meters per kilogram to about 3
Newton-meters per kilogram. Thus, a certain electric motor with a
torque density of 1 Newton-meter per kilogram providing, for
example, 10 total Newton-meters of torque may be quite heavy, for
example in excess of 10 kilograms of active electrical and magnetic
materials. Similarly, another electric motor with a torque density
of 2 Newton-meters per kilogram providing, for example, 100 total
Newton-meters of torque may also be quite heavy, for example in
excess of 50 kilograms of active electrical and magnetic materials.
As can be appreciated, the total weight of these electric motors,
for example including weight of frame components, housings, and the
like, may be significantly higher. Moreover, such prior electric
motors are often quite bulky as a result of the large motor mass.
Often, a motor of sufficient torque and/or power for a particular
application is difficult or even impossible to fit in the available
area.
[0039] Even prior transverse flux machines have been unable to
overcome these difficulties. For example, prior transverse flux
machines have suffered from significant flux leakage. Still others
have offered torque densities of only a few Newton-meters per
kilogram of active electrical and magnetic materials. Moreover,
various prior transverse flux machines have been efficiently
operable only within a comparatively narrow RPM and/or load range.
Additionally, using prior transverse flux machines to generate
substantial output power often required spinning relatively massive
and complicated components (i.e., those involving permanent magnets
and/or relatively exotic, dense and/or expensive flux concentrating
or conducting materials) at high rates of speed. Such high-speed
operation requires additional expensive and/or complicated
components for support and/or system reliability. Moreover, many
prior transverse flux machines are comparatively expensive and/or
difficult to manufacture, limiting their viability.
[0040] In contrast, various of these problems can be solved by
utilizing transverse flux machines configured in accordance with
principles of the present disclosure. As used herein, a "transverse
flux machine" and/or "commutated flux machine" may be any
electrical machine wherein magnetic flux paths have sections where
the flux is generally transverse to a rotational plane of the
machine. In an exemplary embodiment, when a magnet and/or flux
concentrating components are on a rotor and/or are moved as the
machine operates, the electrical machine may be a pure "transverse"
flux machine. In another exemplary embodiment, when a magnet and/or
flux concentrating components are on a stator and/or are held
stationary as the machine operates, the electrical machine may be a
pure "commutated" flux machine. As is readily apparent, in certain
configurations a "transverse flux machine" may be considered to be
a "commutated flux machine" by fixing the rotor and moving the
stator, and vice versa. Moreover, a coil may be fixed to a stator;
alternatively, a coil may be fixed to a rotor.
[0041] Moreover, there is a spectrum of functionality and device
designs bridging the gap between a commutated flux machine and a
transverse flux machine. Certain designs may rightly fall between
these two categories, or be considered to belong to both
simultaneously. Therefore, as will be apparent to one skilled in
the art, in this disclosure a reference to a "transverse flux
machine" may be equally applicable to a "commutated flux machine"
and vice versa.
[0042] Moreover, transverse flux machines and/or commutated flux
machines may be configured in multiple ways. For example, with
reference to FIG. 2A, a commutated flux machine may be configured
with a stator 210 generally aligned with the rotational plane of a
rotor 250. Such a configuration is referred to herein as "axial
gap." In another configuration, with reference to FIG. 2B, a
commutated flux machine may be configured with stator 210 rotated
about 90 degrees with respect to the rotational plane of rotor 250.
Such a configuration is referred to herein as "radial gap."
[0043] With reference now to FIG. 3A, a flux switch 352 in a
commutated flux machine may engage a stator 310 by extending at
least partially into a cavity defined by stator 310. Such a
configuration is referred to herein as "cavity engaged." Turning to
FIG. 3B, flux switch 352 in a commutated flux machine may engage
stator 310 by closely approaching two terminal faces of stator 310.
Such a configuration is referred to herein as "face engaged."
Similar engagement approaches may be followed in transverse flux
machines and are referred to in a similar manner.
[0044] In general, a transverse flux machine and/or commutated flux
machine comprises a rotor, a stator, and a coil. A flux switch may
be located on the stator or the rotor. As used herein, a "flux
switch" may be any component, mechanism, or device configured to
open and/or close a magnetic circuit. (i.e., a portion where the
permeability is significantly higher than air). A magnet may be
located on the stator or the rotor. A coil is at least partially
enclosed by the stator or the rotor. Optionally, flux concentrating
portions may be included on the stator and/or the rotor. With
momentary reference now to FIG. 1A, an exemplary transverse flux
machine 100A may comprise a rotor 150A, a stator 110A, and a coil
120A. In this exemplary embodiment, a magnet may be located on
rotor 150A. With momentary reference now to FIG. 1B, an exemplary
commutated flux machine 100B may comprise a rotor 150B, a stator
110B, and a coil 120B. In this exemplary embodiment, a magnet may
be located on stator 110B.
[0045] Moreover, a transverse flux machine and/or commutated flux
machine may be configured with any suitable components, structures,
and/or elements in order to provide desired electrical, magnetic,
and/or physical properties. For example, a commutated flux machine
having a continuous, thermally stable torque density in excess of
50 Newton-meters per kilogram may be achieved by utilizing a
polyphase configuration. As used herein, "continuous, thermally
stable torque density" refers to a torque density maintainable by a
motor, without active cooling, during continuous operation over a
period of one hour or more. Moreover, in general, a continuous,
thermally stable torque density may be considered to be a torque
density maintainable by a motor for an extended duration of
continuous operation, for example one hour or more, without thermal
performance degradation and/or damage.
[0046] Moreover, a transverse flux machine and/or commutated flux
machine may be configured to achieve low core losses. By utilizing
materials having high magnetic permeability, low coercivity, low
hysteresis losses, low eddy current losses, and/or high electrical
resistance, core losses may be reduced. For example, silicon steel,
powdered metals, plated powdered metals, soft magnetic composites,
amorphous metals, nanocrystalline composites, and/or the like may
be utilized in rotors, stators, switches, and/or other flux
conducting components of a transverse flux machine and/or
commutated flux machine. Eddy currents, flux leakage, and other
undesirable properties may thus be reduced.
[0047] A transverse flux machine and/or commutated flux machine may
also be configured to achieve low core losses by varying the level
of saturation in a flux conductor, such as in an alternating
manner. For example, a flux conducting element in a stator may be
configured such that a first portion of the flux conducting element
saturates at a first time during operation of the stator.
Similarly, a second portion of the same flux conducting element
saturates at a second time during operation of the stator. In this
manner, portions of the flux conducting element have a level of
magnetic flux density significantly below the saturation induction
from time to time, reducing core loss. For example, significant
portions of the flux conducting element may have a level of flux
density less than 25% of the saturation induction within the 50% of
the time of its magnetic cycle. Moreover, any suitable flux density
variations may be utilized.
[0048] Furthermore, a transverse flux machine and/or commutated
flux machine may be configured to achieve low coil losses. For
example, in contrast to a conventional electric motor utilizing a
mass of copper C in one or more coils in order to achieve a desired
output power P, a particular transverse flux machine and/or
commutated flux machine may utilize only a small amount of copper C
(for example, one-tenth as much copper C) while achieving the same
output power P. Additionally, a transverse flux machine and/or
commutated flux machine may be configured to utilize coil material
in an improved manner (for example, by reducing and/or eliminating
"end turns" in the coil). In this manner, resistive losses, eddy
current losses, thermal losses, and/or other coil losses associated
with a given coil mass C may be reduced. Moreover, within a
transverse flux machine and/or commutated flux machine, a coil may
be configured, shaped, oriented, aligned, manufactured, and/or
otherwise configured to further reduce losses for a given coil mass
C.
[0049] Additionally, in accordance with principles of the present
disclosure, a transverse flux machine and/or commutated flux
machine may be configured to achieve a higher voltage constant. In
this manner, the number of turns in the machine may be reduced, in
connection with a higher frequency. A corresponding reduction in
coil mass and/or the number of turns in the coil may thus be
achieved.
[0050] Yet further, in accordance with principles of the present
disclosure, a transverse flux machine and/or commutated flux
machine may be configured to achieve a high flux switching
frequency, for example a flux switching frequency in excess of 1000
Hz. Because flux is switched at a high frequency, torque density
may be increased.
[0051] With reference now to FIG. 4, a typical conventional
electric motor efficiency curve 402 for a particular torque is
illustrated. Revolutions per minute (RPM) is illustrated on the X
axis, and motor efficiency is illustrated on the Y axis. As
illustrated, a conventional electric motor typically operates at a
comparatively low efficiency at low RPM. For this conventional
motor, efficiency increases and then peaks at a particular RPM, and
eventually falls off as RPM increases further. As a result, many
conventional electric motors are often desirably operated within an
RPM range near peak efficiency. For example, one particular prior
art electric motor may have a maximum efficiency of about 90% at
about 3000 RPM, but the efficiency falls off dramatically at RPMs
that are not much higher or lower.
[0052] Gearboxes, transmissions, and other mechanical mechanisms
are often coupled to an electric motor to achieve a desired output
RPM or other output condition. However, such mechanical components
are often costly, bulky, heavy, and/or impose additional energy
losses, for example frictional losses. Such mechanical components
can reduce the overall efficiency of the motor/transmission system.
For example, an electric motor operating at about 90% efficiency
coupled to a gearbox operating at about 70% efficiency results in a
motor/gearbox system having an overall efficiency of about 63%.
Moreover, a gearbox may be larger and/or weigh more or cost more
than the conventional electric motor itself. Gearboxes also reduce
the overall reliability of the system.
[0053] In contrast, with continuing reference to FIG. 4 and in
accordance with principles of the present disclosure, a transverse
and/or commutated flux machine efficiency curve 404 for a
particular torque is illustrated. In accordance with principles of
the present disclosure, a transverse and/or commutated flux machine
may rapidly reach a desirable efficiency level (for example, 80%
efficiency or higher) at an RPM lower than that of a conventional
electric motor. Moreover, the transverse and/or commutated flux
machine may maintain a desirable efficiency level across a larger
RPM range than that of a conventional electric motor. Additionally,
the efficiency of the transverse and/or commutated flux machine may
fall off more slowly past peak efficiency RPM as compared to a
conventional electric motor.
[0054] Furthermore, in accordance with principles of the present
disclosure, a transverse and/or commutated flux machine may achieve
a torque density higher than that of a conventional electric motor.
For example, in an exemplary embodiment a transverse and/or
commutated flux machine may achieve a continuous, thermally stable
torque density in excess of 100 Newton-meters per kilogram.
[0055] Thus, in accordance with principles of the present
disclosure, a transverse and/or commutated flux machine may
desirably be employed in various applications. For example, in an
automotive application, a transverse and/or commutated flux machine
may be utilized as a wheel hub motor, as a direct driveline motor,
and/or the like. Moreover, in an exemplary embodiment having a
sufficiently wide operational RPM range, particularly at lower
RPMs, a transverse and/or commutated flux machine may be utilized
in an automotive application without need for a transmission,
gearbox, and/or similar mechanical components.
[0056] An exemplary electric or hybrid vehicle embodiment comprises
a transverse flux motor for driving a wheel of the vehicle, wherein
the vehicle does not comprise a transmission, gearbox, and/or
similar mechanical component(s). In this exemplary embodiment, the
electric or hybrid vehicle is significantly lighter than a similar
vehicle that comprises a transmission-like mechanical component.
The reduced weight may facilitate an extended driving range as
compared to a similar vehicle with a transmission like mechanical
component. Alternatively, weight saved by elimination of the
gearbox allows for utilization of additional batteries for extended
range. Moreover, weight saved by elimination of the gearbox allows
for additional structural material for improved occupant safety. In
general, a commutated flux machine having a broad RPM range of
suitable efficiency may desirably be utilized in a variety of
applications where a direct-drive configuration is advantageous.
For example, a commutated flux machine having an efficiency greater
than 80% over an RPM range from only a few RPMs to about 2000 RPMs
may be desirably employed in an automobile.
[0057] Moreover, the exemplary transmissionless electric or hybrid
vehicle may have a higher overall efficiency. Stated otherwise, the
exemplary vehicle may more efficiently utilize the power available
in the batteries due to the improved efficiency resulting from the
absence of a transmission-like component between the motor and the
wheel of the vehicle. This, too, is configured to extend driving
range and/or reduce the need for batteries.
[0058] Additionally, the commutated flux machine is configured to
have a high torque density. In accordance with principles of the
present disclosure, the high torque density commutated flux machine
is also well suited for use in various applications, for example
automotive applications. For example, a conventional electric motor
may have a torque density of between about 0.5 to about 3
Newton-meters per kilogram. Additional techniques, for example
active cooling, can enable a conventional electric motor to achieve
a torque density of up to about 50 Newton-meters per kilogram.
However, such techniques typically add significant additional
system mass, complexity, bulk, and/or cost. Additionally, such
conventional electric motors configured to produce comparatively
high amounts of torque, for example the Siemens 1FW6 motor, are
limited to comparatively low RPM operation, for example operation
below 250 RPMs.
[0059] In contrast, in accordance with principles of the present
disclosure, an exemplary passively cooled transverse flux machine
and/or commutated flux machine may be configured with a continuous,
thermally stable torque density in excess of 50 Newton-meters per
kilogram. As used herein, "passively cooled" is generally
understood to refer to systems without cooling components requiring
power for operation, for example water pumps, oil pumps, cooling
fans, and/or the like. Moreover, this exemplary transverse flux
machine and/or commutated flux machine may be configured with a
compact diameter, for example a diameter less than 14 inches.
Another exemplary transverse flux machine and/or commutated flux
machine may be configured with a continuous, thermally stable
torque density in excess of 100 Newton-meters per kilogram and a
diameter less than 20 inches. Accordingly, by utilizing various
principles of the present disclosure, exemplary transverse flux
machines and/or commutated flux machines may be sized and/or
otherwise configured and/or shaped in a manner suitable for
mounting as a wheel hub motor in an electric vehicle, because the
transverse flux machine and/or commutated flux machine is
significantly lighter and/or more compact than a conventional
electric motor. In this manner, the unsprung weight of the
resulting wheel/motor assembly can be reduced. This can improve
vehicle handling and reduce the complexity and/or size of
suspension components.
[0060] Further, in accordance with principles of the present
disclosure, a transverse flux machine and/or commutated flux
machine may desirably be utilized in an electromechanical system
having a rotating portion, for example a washing machine or other
appliance. In one example, a conventional washing machine typically
utilizes an electric motor coupled to a belt drive to spin the
washer drum. In contrast, a transverse flux machine and/or
commutated flux machine may be axially coupled to the washer drum,
providing a direct drive configuration and eliminating the belt
drive element. Alternatively, a transverse flux machine and/or
commutated flux machine, for example one comprising a partial
stator, may be coupled to a rotor. The rotor may have a common axis
as the washer drum. The rotor may also be coupled directly to the
washer drum and/or integrally formed therefrom. In this manner, a
transverse flux machine and/or commutated flux machine may provide
rotational force for a washing machine or other similar
electromechanical structures and/or systems.
[0061] Moreover, in accordance with principles of the present
disclosure, a transverse flux machine and/or commutated flux
machine may desirably be utilized to provide mechanical output to
relatively lightweight vehicles such as bicycles, scooters,
motorcycles, quads, golf carts, or other vehicles. Additionally, a
transverse flux machine and/or commutated flux machine may
desirably be utilized in small engine applications, for example
portable generators, power tools, and other electrical equipment. A
transverse flux machine and/or commutated flux machine may
desirably be utilized to provide mechanical output to
propeller-driven devices, for example boats, airplanes, and/or the
like. A transverse flux machine and/or commutated flux machine may
also desirably be utilized in various machine tools, for example
rotating spindles, tables configured to move large masses, and/or
the like. In general, transverse flux machines and/or commutated
flux machines may be utilized to provide electrical and/or
mechanical input and/or output to and/or from any suitable
devices.
[0062] An electrical system, for example an electric motor, may be
any system configured to facilitate the switching of magnetic flux.
In accordance with an exemplary embodiment and with reference again
to FIG. 1A, an electrical system, for example transverse flux
machine 100A, generally comprises a rotor portion 150A, a stator
portion 110A, and a coil 120A. Rotor portion 150A is configured to
interact with stator portion 110A in order to facilitate switching
of magnetic flux. Stator portion 110A is configured to be
magnetically coupled to rotor portion 150A, and is configured to
facilitate flow of magnetic flux via interaction with rotor portion
150A. Coil 120A is configured to generate an output responsive to
flux switching and/or accept a current input configured to drive
the rotor. Transverse flux machine 100A may also comprise various
structural components, for example components configured to
facilitate operation of transverse flux machine 100A. Moreover,
transverse flux machine 100A may comprise any suitable components
configured to support, guide, modify, and/or otherwise manage
and/or control operation of transverse flux machine 100A and/or
components thereof.
[0063] In accordance with an exemplary embodiment and with renewed
reference to FIG. 1B, a commutated flux machine (CFM) system 100B
comprises a stator 110 (for example, stator 110B), a rotor 150 (for
example, rotor 150B), and a coil 120 (for example, coil 120B). In
various embodiments, CFM system 100B has a generally
circumferential stator which comprises multiple magnets 111B and
flux concentrators 112B to form a complete circle. In an exemplary
embodiment, stator 110B partially encloses coil 120B. Furthermore,
rotor 150B has passive switching elements 151B, and rotates to
interact with stator 110B and switch magnetic flux.
[0064] In an exemplary embodiment of the circumferential stator
110B, magnets 111B and flux concentrators 112B are arranged in
alternating fashion. In one exemplary embodiment, magnets 111B are
magnetically oriented in alternating directions while interleaving
with flux concentrators 112B. Stated another way, magnets 111B may
be arranged so that a north magnetic side of a particular magnet
111B is facing a north magnetic side of another magnet 111B, with a
flux concentrator 112B therebetween. Likewise, a south magnetic
side may be oriented facing another south magnetic side, separated
by a flux concentrator 112B. The interleaving and alternating
directions result in each flux concentrator 112B having a net
magnetic pole.
[0065] In an exemplary embodiment, and with reference now to FIG.
5, a transverse and/or commutated flux machine may be implemented
with multiple partial stators, for example as a wheel hub motor.
For example, a transverse flux machine 500 may comprise a rotor
550, one or more coils 520 (shown as 520A and 520B), and one or
more partial stators 510 (shown as 510A, 510B, and 510C). Moreover,
via use of a plurality of partial stators, transverse flux machine
500 may be configured to produce polyphase output and/or operate
responsive to polyphase input, for example when each of the
plurality of partial stators correspond to a different phase.
[0066] With reference now to FIG. 6, in an exemplary embodiment a
CFM stator unit 610 comprises a flux concentrator 612 and a magnet
611 that are both substantially C-shaped. The C-shaped components
611, 612 can be defined as having a first leg 615, a second leg
616, and a return portion 617 that connects to the first and second
legs 615, 616. In an exemplary embodiment, CFM stator unit 610 is
generally C-shaped to accommodate a substantially annular or
doughnut shaped rotor portion 650 in a cavity engaged
configuration. In another exemplary embodiment, CFM stator unit 610
is configured to be face engaged with rotor portion 650.
Furthermore, in addition to C-shaped, in exemplary embodiments the
shapes of the stator components may be U-shaped, rectangular,
triangular, rounded cross-sectional shapes, and/or any other
suitable shapes known to one skilled in the art.
[0067] In an exemplary embodiment, a stator further comprises a
structural support that holds the magnets and flux concentrators
for assembly and/or spacing. The structural support is designed to
not interfere with the motion of the CFM system. In another
exemplary embodiment, the stator further comprises cooling devices.
The cooling devices may include radiative portions, conductive
cooling portions, and/or the like. In yet another exemplary
embodiment, the stator may also comprise components that measure
certain characteristics of the device, such as Hall effect sensors
and/or the like. Furthermore, in various exemplary embodiments the
stator comprises components configured to drive the rotor.
[0068] With reference again to FIG. 6, CFM stator unit 610 may at
least partially enclose a coil 620. Coil 620 may be any suitable
height, width, and/or length to generate an electrical current
responsive to flux switching in the stator. Coil 620 may also be
any suitable height, width, and/or length configured to transfer a
current to drive the rotor. In an embodiment, coil 620 is circular
about an axis of rotation. In various exemplary embodiments, coil
620 has a diameter of between approximately 2 inches and
approximately 36 inches in the plane of rotation. Moreover, coil
620 may have any suitable diameter, length, and/or other dimensions
and/or geometries, as desired.
[0069] In an exemplary embodiment, coil 620 is coupled to an
interior surface of concentrator 611. Moreover, in another
exemplary embodiment, concentrator 611 is "wrapped" around coil 620
so that the interior surface of concentrator 611 is slightly larger
than the height and width of coil 620 with as little as gap as
possible. Coil 620 may also be desirably spaced away from and/or
magnetically insulated from rotor switch 650, for example in order
to reduce eddy currents and/or other induced effects in coil 620
responsive to flux switching near the surface of rotor switch
650.
[0070] In an exemplary embodiment, coil 620 is electrically coupled
to a current source. The current source may be any suitable current
source, but in one exemplary embodiment the current source is
alternating power. It should be noted that coil 620 could be
connected to be a source in general applications.
[0071] In an exemplary embodiment, coil 620 is generally
constructed from copper. However, coil 620 may be made out of any
suitable electrically conductive material and/or materials such as
copper, silver, gold, aluminum, superconducting materials, and/or
the like. In an exemplary embodiment, coil 620 is a loop. The loop
is in contrast to windings, which may have greater losses than a
single loop. Furthermore, coil 620 may be one solid piece, or may
be made by coiling, layering, stacking, and/or otherwise joining
many smaller strands or wires of electrically conductive material
and/or low-loss materials together.
[0072] In accordance with an exemplary embodiment, the stator and
rotor interact to create a magnetic flux circuit. Flux conduction
is created, for example, by the switching elements of the rotor
bridging the gap between opposite pole flux concentrators. In an
exemplary embodiment, opposite pole flux concentrators are adjacent
in the stator. In various exemplary embodiments, a flux path is
created through the switching elements of the rotor. In another
exemplary embodiment, a flux path is created through a magnet
separating the adjacent flux concentrators. In an exemplary
embodiment, AC synchronous flux flow is generated in response to
similar flux conduction and flux paths being created simultaneously
in adjacent flux concentrators. In another exemplary embodiment,
asynchronous flux flow is generated in response to flux conduction
and flux paths being created in adjacent flux concentrators at
slightly delayed intervals.
[0073] In an exemplary generator embodiment, as the rotor moves
into new position relative to the stator, flux flows in an opposite
direction within the stator as compared to a prior position of the
rotor. The change in flux direction causes the flux to be conducted
around the coil in alternating directions. The alternating flux
direction results in generation of alternating electrical output in
the coil.
[0074] In an exemplary motor embodiment, the rotor is driven to
rotate. The rotor movement is controlled, in an exemplary
embodiment, by a control system which controls, for example, rotor
RPM, axial positioning, acceleration, rotational direction,
deceleration, starting, and/or stopping. In an exemplary
embodiment, the rotor is driven in either direction (clockwise or
counterclockwise), for example depending on a preference of an
operator. The control system may further comprise programming
memory, and a user interface, which may include graphics. The
control system may include ports for coupling to additional
electrical devices and/or may be coupled to additional electrical
devices wirelessly. The control system may further comprise sensors
for monitoring and measuring desired values of the system. These
values may include one or more of phase matching, phase
propagation, output waveforms, flux density, voltage constant,
torque constant, webers of flux switched, RPM, system malfunctions,
and/or the like. A power source may be coupled to the control
system. This power source may be any suitable power source for
operation of the control system, such as alternating current,
direct current, capacitive charge, and/or inductance. In an
exemplary embodiment, the power source is a DC battery.
[0075] Portions of rotor and/or stator elements may comprise any
suitable flux conducting material and/or materials, such as steel,
silicon steel, amorphous metals, metallic glass alloys,
nanocrystalline composite, and powdered metals such as powdered
iron.
[0076] In an exemplary embodiment, portions of a commutated and/or
transverse flux machine, for example CFM system 100B, such as
portions of the stator 110B or rotor 150B may be comprised of
Metglas.RTM. brand amorphous metal products produced by Hitachi
Metals America, for example Metglas.RTM. brand magnetic alloy
2605SA1 and/or the like. In general, such magnetic alloys have
excellent flux conducing properties (e.g., permeability, for
example, may be up to hundreds of thousands of times the
permeability of silicon steel). Such magnetic alloys are also
resistant to the effects of heat and losses), such as may occur
with high speed operation of devices in accordance with aspects of
the present disclosure. For example, losses for devices using such
magnetic alloys, compared to using silicon steel, may be reduced
from about 800 watts to about 30 watts or less, in some exemplary
applications. Moreover, utilization of such magnetic alloys can
allow for higher speed operation without the need for auxiliary
cooling. For example, a device using magnetic alloy in place of
silicon steel may be configured to achieve a continuous operation
at a higher RPM, for example an RPM two times greater, five times
greater, ten times greater, or even more. These features, in
addition to other factors, allow the power to weight ratios of
exemplary transverse and/or commutated flux devices to
increase.
[0077] In certain exemplary embodiments, portions of CFM system
100B, such as portions of stator 110B or rotor 150B, may be
comprised of stacked laminated steel. The orientation of the
laminations may be varied to enhance flux transmission. For
instance, certain laminations may be oriented in a radial
direction. This approach may enhance mechanical strength and/or
ease assembly. Alternatively, such as for a return portion in a
flux conducting element of a stator, the surfaces of the
laminations may be oriented parallel to the direction of flux
transmission, thereby reducing eddy currents and/or other losses.
Minimizing eddy current effects and/or otherwise enhancing flux
transmission can be achieved using powdered iron; however, powdered
iron generally does not conduct magnetic flux as efficiently as,
for example, steel laminate (or other flux conducting material,
such as Metglas.RTM. 2605SA1) and does not include the physical
layer features potentially useful in minimizing or otherwise
addressing eddy current and other losses. In addition, the use of
powdered iron has the further drawback of increased hysteresis
losses.
[0078] In an exemplary embodiment, portions of CFM system 100B,
such as portions of the stator magnets, may comprise rare earth
permanent magnets. Magnetic material may comprise any suitable
material, for example neodymium-iron-boron (NIB) material. In an
exemplary embodiment, the rare earth permanent magnets have a
suitable magnetic field, for example a field in the range of 0.5 to
2.5 Tesla. In other exemplary embodiments, the stator magnets
comprise inducted magnets and/or electromagnets. The inducted
magnets and/or electromagnets may be made out of iron, iron alloys,
metallic alloys, and/or the like, as well as other suitable
materials as is known.
[0079] In an exemplary embodiment, a flux concentrator gathers the
flux from one or more coupled magnets. A flux concentrator is
typically made of some form of iron, such as silicon steel,
powdered metals, amorphous metals, metallic glass alloys,
nanocrystalline composite, and/or the like. Furthermore, in various
exemplary embodiments, the flux concentrator may be made out of any
suitable material, for example a material with a high permeability,
high flux saturation, and/or high electrical resistance.
[0080] In addition to a circumferential CFM system as described,
various other configurations of a CFM stator may be utilized. These
other configurations include, but are not limited to, a gapped
stator, a partial stator, and a floating stator.
[0081] In an exemplary embodiment and with reference now to FIG. 7,
a gapped stator CFM system 700 comprises multiple commutated flux
stator sections 701 assembled generally about the circumference of
a coil 720 and a rotor 750. The gapped stator CFM system 700
further comprises a gap 702 between each of the multiple commutated
flux stator sections 701. Furthermore, in an exemplary embodiment,
a structural support (not shown) is located in gap 702 of gapped
stator system 700.
[0082] In accordance with an exemplary embodiment, gapped stator
CFM system 700 further comprises a support structure. The support
structure holds multiple commutated flux stator sections 701 into
place. In an exemplary embodiment, the support structure comprises
several sections configured to hold the magnets and flux
concentrators. Commutated flux stator sections 701 may be
partitioned using spacers, for example portions of the support
structure. The spacers may be configured to provide proper
alignment of the multiple commutated flux stator sections 701. In
an exemplary embodiment, the spacers are approximately as thick as
a magnet in commutated flux stator sections 701. Moreover, the
spacers may have any suitable thickness, as desired.
[0083] In various exemplary embodiments, the number of commutated
flux stator sections 701 in gapped stator system 700 may range from
2 to 360 or more. The arc length of the multiple commutated flux
stator sections 701 is less than the circumference of rotor 750. As
defined herein, the arc length of multiple commutated flux stator
sections 701 is the encompassed distance of rotor 750, not
including the gap distance. In various exemplary embodiments, the
total arc length of multiple commutated flux stator sections 701 is
in the range of about 1% to about 95% of the circumference of rotor
750. In one embodiment, multiple commutated flux stator sections
701 are equally distributed about rotor 750 to form a substantially
circumferential stator. In another embodiment, multiple commutated
flux stator sections 701 are unequally distributed about rotor 750.
For example, multiple commutated flux stator sections 701 may be
located on only half of the circumference of rotor 750.
[0084] In another example, multiple commutated flux stator sections
701 are configured with uneven distances between each section.
However, in an AC synchronous embodiment, multiple commutated flux
stator sections 701 are typically located such that the switching
portions of rotor 750 can magnetically engage each of multiple
commutated flux stator sections 701. This can be accomplished, for
example, by designing the distance between multiple commutated flux
stator sections 701 to be a multiple of the distance between the
switching elements of rotor 750.
[0085] In an exemplary embodiment, first magnet 711 has an outer
edge parallel to, and opposite of, the interface between first
magnet 711 and flux concentrator 712. Similarly, in the exemplary
embodiment, second magnet 713 has an outer edge parallel to, and
opposite of, the interface between second magnet 713 and flux
concentrator 712. Stated another way, commutated flux stator
section 701, in one embodiment, is "square" with respect to coil
720. In an exemplary embodiment, a "square" commutated flux stator
section 701 facilitates manufacturing and assembly. In a modular
approach, each commutated flux stator section 701 is manufactured
with substantially flush inner cavities instead of rounded inner
cavities. However, magnets 711, 713 and/or flux concentrator 712
can also be angled. For example, magnets 711, 713 might have a
narrow first leg in comparison to the second leg, creating a
tapered shape. Furthermore, flux concentrator 712 can also be
tapered towards the axis of rotation of rotor 750. Moreover,
magnets 711, 712 and/or flux concentrators 712 may be shaped,
sized, and/or otherwise configured in any suitable manner, for
example to achieve a desired torque density, output voltage
waveform, and/or the like.
[0086] An advantage of a gapped stator configuration compared to a
similar circumferential stator configuration is a decrease in
weight. Another advantage is a decrease in the amount of magnetic
material. Less magnetic material can result in a less expensive
system. A decrease is weight is an advantage in various
applications where a lower power is sufficient but extra weight is
undesirable, for example due to structural stress.
[0087] In an exemplary embodiment, gaps 702 between commutated flux
stator sections 701 are configured to provide ventilation for
cooling. In other exemplary embodiments, various heat extraction
devices such as heat sinks, other heat dispersive materials, fan
blades, and/or other suitable devices may be added to and/or placed
at least partially within gaps 702 between commutated flux stator
sections 701.
[0088] Furthermore, in addition to cooling devices, other devices
may be located in gaps 702 between commutated flux stator sections
701. In an exemplary embodiment, one or more measuring devices are
located in gaps 702. The measuring devices, for example, may
include devices to measure RPM, magnetic field strength, efficiency
of the system, and/or the like.
[0089] Another advantage of gapped stator CFM system 700 is
generally directed to assembly and/or repair of the stator. In an
exemplary embodiment, commutated flux stator sections 701 are
modular. Moreover, sections 701 may be separately removable and/or
removable in multiple groups. Such a modular approach to assembly
and/or disassembly results in easier replacement, as the removal
and replacement of a section does not necessitate removing
additional sections.
[0090] Also, the presence of gaps 702 enables a more forgiving
manufacturing tolerance for gapped stator CFM system 700. For
example, when alternating magnets and flux conducting elements are
repeatedly stacked together, manufacturing tolerance variations can
be cumulative, leading to magnets and/or flux conducting elements
that are out of a desired alignment. By utilizing one or more gaps
702, the location of magnets and/or flux conducting elements can be
periodically re-zeroed, eliminating tolerance stackup. As can be
appreciated, less precisely manufactured components may thus be
effectively utilized, reducing the expense of the system.
Furthermore, the dimensions of gaps 702 may also be a function of
at least one of an on-center distance between poles in gapped
stator CFM system 700, a switch thickness of rotor 750, or the
number of poles in gapped stator CFM system 700.
[0091] In addition to gapped stators disclosed above, principles of
the present disclosure also contemplate "partial" or "truncated"
stators. In accordance with an exemplary embodiment, a partial
stator system comprises a stator that forms less than 360.degree.
coverage of a disk-shaped and/or annular rotor. In an exemplary
embodiment, and with reference to FIG. 8A, a partial stator system
800 comprises a partial stator 810 and a rotor 850. Partial stator
system 800 may be a portion of a fully circumferential stator
design. For example, partial stator 810 may be coupled to less than
25% of the circumference of rotor 850. In another embodiment,
partial stator 810 is coupled to less than 50% of the circumference
of rotor 850. Moreover, partial stator 810 may at least partially
enclose a portion of the circumference of rotor 850, for example a
portion in the range of 1%-95%. In various embodiments, the range
may be from 1%-75%, 2%-66%, or 5%-33%. Furthermore, the
relationship with partial stator 810 and rotor 850 may be described
in terms of relative arc lengths. For example, partial stator 810
may have an arc length less than 25% of the arc length of rotor
850.
[0092] In an exemplary embodiment and as illustrated in FIGS. 8B
and 8C, a partial stator system 800 can also comprise gapped stator
sections as previously described. In an exemplary embodiment,
partial stator system 800 is an axial gap configuration, as shown
in FIG. 2A. In another exemplary embodiment, partial stator system
800 is a radial gap configuration, as shown in FIG. 2B.
[0093] In various exemplary embodiments, partial stator system 800
is configured with an engagement between stator 810 and rotor 850.
This engagement can be utilized for different purposes. For
example, the engagement can be tailored for different sized rotors
and/or different shaped rotors. Furthermore, in an exemplary
embodiment the engagement is designed for at least one of:
tailoring a voltage constant, tailoring a torque constant,
tailoring a power density, or optimizing voltage and/or torque
density for a specific application, and/or the like. Moreover, if
partial stator system 800 comprises multiple stator sections, any
particular stator section may be individually adjusted, for example
for one of reasons set forth above.
[0094] Moreover, multiple partial stator sections may desirably be
utilized, for example, in order to product polyphase output and/or
respond to polyphase input. In various exemplary embodiments,
multiple partial stator sections may be utilized, each
corresponding to a different phase. However, any combination of
partial stator sections and/or phases may be utilized, as
desired.
[0095] In general, partial stator system 800 may be desirably
utilized if an application requires less than the maximum power
obtainable with a fully circumferential stator. In an exemplary
embodiment, a number of commutated flux stator sections in partial
stator system 800 can be customized to an application's
requirements, for example a desired power output, efficiency,
expense, and/or the like. In an exemplary embodiment, partial
stator system 800 is designed based in part on a ratio between
desired electrical output and the mass of system 800. Partial
stator system 800 may also be designed in part based on the ratio
between a rotor diameter and either of the electrical output or
weight of system 800. In an exemplary embodiment, partial stator
system 800 achieves more torque without increasing the amount of
the stator material by increasing the diameter of the rotor.
[0096] Such applications may include bikes, scooters, washing
machines, motorcycles, portable generators, power tools, and/or
small engine applications. Partial stators may offer many and/or
all of the benefits of gapped stators as discussed above. Moreover,
partial stator system 800 may provide improved serviceability, for
example because the stator components are more accessible and/or
easier to assemble/disassemble compared to a fully circumferential
stator.
[0097] Partial and/or gapped stators may be coupled to other
components, for example control electronics. In an exemplary
embodiment and with reference to FIG. 9A, a partial stator system
900 further comprises an electronics board 901 to capture the
generated output from a coil 920. In another exemplary embodiment,
electronics board 901 can be configured to provide power to partial
stator system 900, for example delivering power to drive a rotor.
Furthermore, in an exemplary embodiment, partial stator system 900
may be implemented within a commutated flux machine and/or a
transverse flux machine. In one exemplary embodiment, a partial
stator 910 is electrically connected to a truncated coil 920 that
is mounted directly to electronics board 901. Electronics board 901
may, in an exemplary embodiment, include various electronic
components 930. In an exemplary embodiment, electronic components
930 include integrated circuits, capacitors, invertors, and other
suitable components, as desired.
[0098] Furthermore, in an exemplary embodiment, electronics board
901 is located a short distance from partial stator 910, and thus
the length of truncated coil 920 from partial stator 910 to
electronics board 901 is also short. In an exemplary embodiment,
the length of truncated coil 920 from partial stator 910 to
electronics board 901 is 1 inch or less. In another embodiment, the
length of truncated coil 920 from partial stator 910 to electronics
board 901 is in the range of 1-2 inches. Moreover, the length of
truncated coil 920 may be any suitable length; however, the length
of truncated coil 920 may often be desirably minimized to reduce
resistive and/or other losses.
[0099] In accordance with an exemplary embodiment, a thickness to
length ratio of truncated coil 920 is configured to permit a
significant percentage of heat generated in truncated coil 920 to
be removed conductively. In an exemplary embodiment, a significant
percentage may be 70% or more of the generated heat. In various
exemplary embodiments, a significant percentage may be between
about 40% of the generated heat and 95% of the generated heat. With
the appropriate physical dimensions and/or material properties, in
an exemplary embodiment, truncated coil 920 can significantly cool
itself conductively. In an exemplary embodiment, the ratio of the
length of truncated coil 920 to the thickness of truncated coil 920
is about 20:1. In various exemplary embodiments, the ratio may be
between about 10:1 to about 75:1. Moreover, the ratio may be any
suitable ratio configured to allow truncated coil 920 to
conductively transfer a suitable amount of heat, for example heat
generated within the portion of truncated coil 920 at least
partially enclosed by truncated stator 910.
[0100] Moreover, additional components, for example cooling
components 931, may be coupled directly to coil 920. In an
exemplary embodiment, cooling components 931 may utilize at least
one of radiant, convective, or conductive cooling. Cooling
components 931 may also be formed from and/or comprise a portion of
coil 920. In this manner, thermal energy transferred from coil 920
to electronics board 901 may be reduced. Moreover, a rotor coupled
to partial stator system 900 generally cools more effectively than
a rotor in a fully circumferential stator system. This is due at
least in part to the rotor only conducting flux in a portion of the
rotation, which results in less heating of the rotor, also provides
time for the rotor to cool when not conducting flux.
[0101] Furthermore, in various exemplary embodiments, truncated
coil 920 is configured with minimal end turn material and/or no end
turn material. An end turn may be considered to be a portion of a
coil that is not linked by substantial flux. In other words, the
portion of the coil that is not coupled to a flux concentrator
and/or magnets may be considered to be an end turn. In general, end
turns are undesirable because they incur coil losses without doing
useful work. For example, an end turn of a traditional motor incurs
large losses as current flows through an end turn coil portion.
Coil losses may include resistive losses, eddy current losses,
thermal losses, and/or other coil losses associated with a given
coil mass and/or configuration. Furthermore, heating of the coil
due to resistance is also reduced if using less coil material. In
one embodiment, truncated coil 920 comprises a monolithic material
core. Moreover, truncated coil 920 may comprise any suitable
material, for example layered, laminated, and/or otherwise shaped
and/or formed material, as desired.
[0102] In various exemplary embodiments, multiple commutated flux
stator sections each have a corresponding truncated coil 920 in a
single winding configuration, which can be connected to a single
electronics board 901 (see, e.g., FIG. 9C). In other exemplary
embodiments, truncated coil 920 comprises a double winding and/or
more windings (see, e.g., FIG. 9B).
[0103] In addition to partial and/or gapped stators, principles of
the present disclosure contemplate "floating" stators. As used
herein, a "floating" stator may be a stator configured to be at
least partially adjustable and/or moveable with respect to a rotor,
for example in order to maintain a desired air gap. With reference
now to FIGS. 10A and 10B, in an exemplary embodiment a floating
stator system 1000 comprises a partial stator 1010, a rotor 1050,
and one or more guide mechanisms 1011. Rotor 1050 may be attached
to another object and held in place, and stator 1010 may be capable
of floating. Alternatively, stator 1010 may be attached to another
object and held in place, and rotor 1050 may be capable of
floating.
[0104] In an exemplary embodiment, guide mechanisms 1011 are
configured to help align rotor 1050 and/or mechanically facilitate
a size of an air gap between rotor 1050 and partial stator 1010.
Prior systems were often unable to achieve a targeted air gap as
the diameter of the rotor increased. For example, many motors
and/or generators are configured with an air gap no smaller than
1/250 of the diameter of the rotor, in order to prevent the rotor
and stator from contacting and/or damaging one another. This is
generally due to manufacturing tolerances and/or other
difficulties, for example the difficulty of producing perfectly
round components.
[0105] In contrast, via use of a floating stator 1010, floating
stator system 1000 can be configured with an air gap independent of
the diameter of a rotor. For example, in an exemplary embodiment,
floating stator system 1000 is configured with a rotor diameter of
36 inches. This floating stator system 1000 may also be configured
with an air gap of only 0.036 inches. In contrast, prior motors
and/or generators having a similar rotor diameter were often
configured with an air gap no smaller than 0.144 inches (i.e., an
air gap no small than 1/250 of the diameter of the rotor). By
decoupling selecting an air gap from a corresponding rotor
diameter, commutated and/or transverse flux systems having large
rotor diameters (and corresponding high torque) may be configured
with narrow air gaps, improving the performance of the system.
Stated another way, floating stator 1010 is capable of adjusting to
gradual deviations in the diameter of the rotor.
[0106] Guide mechanisms 1011 may be at least one of wheels, rails,
bearings, bumpers, spacers, lubricious material, and/or the like.
Moreover, guide mechanisms may be any suitable device configured to
direct, guide, and/or align rotor 1050 and partial stator 1010. In
various exemplary embodiments, guide mechanisms 1011 also function
to help clean off debris from rotor 1050. In these embodiments,
guide mechanisms 1011 further comprise at least one of brushes, air
or gas jets, wipers, or magnetic pick-up wipers to deflect magnetic
debris. Moreover, guide mechanisms 1011 may comprise any suitable
mechanism for clearing debris from rotor 1050.
[0107] Floating rotors can improve device manufacturing tolerances,
ease of manufacturing, and robustness of overall design. Moreover,
in an exemplary embodiment, a floating rotor further comprises a
hubless design, such that the rotor is not connected to a central
hub. In this manner, increased space in the middle of the rotor is
provided. Moreover, such a hubless design can increase heat
dissipation capabilities, for example by providing additional room
for cooling airflow.
[0108] Furthermore, a hubless design may be configured to increase
the floating capabilities of the rotor and/or stator, and/or to
allow more tolerance within the system. Such increased floating
and/or tolerance may be useful in flux machines that undergo sudden
changes of direction, for example when installed in a vehicle. For
example, in a vehicle, turning may increase a chance of a rotor and
stator scraping, due to the angular momentum of the system.
Moreover, in a vehicle, a rotor and stator may scrape and/or
otherwise contact one another in an undesirable manner for various
reasons, for example contact with a pothole, lateral acceleration
during a turn, an external force, and/or the like. A hubless design
may be configured to prevent rotor/stator contact resulting from
any and/or all of the foregoing.
[0109] Suitable methods of forming and/or materials for stators,
rotors, coils, switches, flux concentrators, and/or other flux
conducting components of transverse and/or commutated flux machines
may be found in U.S. patent application Ser. No. 12/611,733 filed
Nov. 3, 2009, now U.S. Pat. No. 7,923,886 entitled "TRANSVERSE
AND/OR COMMUTATED FLUX SYSTEM ROTOR CONCEPTS". Principles of the
present disclosure may suitably be combined therewith.
[0110] Principles of the present disclosure may also suitably be
combined with principles for rotors in transverse flux machines
and/or commutated flux machines as disclosed in U.S. patent
application Ser. No. 12/611,733 filed Nov. 3, 2009, now U.S. Pat.
No. 7,923,886 entitled "TRANSVERSE AND/OR COMMUTATED FLUX SYSTEM
ROTOR CONCEPTS", the contents of which are hereby incorporated by
reference in their entirety.
[0111] Principles of the present disclosure may also suitably be
combined with principles of polyphase transverse flux machines
and/or polyphase commutated flux machines as disclosed in U.S.
patent application Ser. No. 12/611,737 filed Nov. 3, 2009, now U.S.
Pat. No. 7,686,508 entitled "POLYPHASE TRANSVERSE AND/OR COMMUTATED
FLUX SYSTEMS", the contents of which are hereby incorporated by
reference in their entirety.
[0112] Moreover, principles of the present disclosure may suitably
be combined with any number of principles disclosed in any one of
and/or all of the U.S. patent applications incorporated by
reference herein. Thus, for example, a particular commutated flux
machine may incorporate use of a partial stator, use of a tape
wound rotor, use of a polyphase design, and/or the like. All such
combinations, permutations, and/or other interrelationships are
considered to be within the scope of the present disclosure.
[0113] While the principles of this disclosure have been shown in
various embodiments, many modifications of structure, arrangements,
proportions, the elements, materials and components, used in
practice, which are particularly adapted for a specific environment
and operating requirements may be used without departing from the
principles and scope of this disclosure. These and other changes or
modifications are intended to be included within the scope of the
present disclosure and may be expressed in the following
claims.
[0114] In the foregoing specification, the invention has been
described with reference to various embodiments. However, one of
ordinary skill in the art appreciates that various modifications
and changes can be made without departing from the scope of the
present disclosure. Accordingly, the specification is to be
regarded in an illustrative rather than a restrictive sense, and
all such modifications are intended to be included within the scope
of the present disclosure. Likewise, benefits, other advantages,
and solutions to problems have been described above with regard to
various embodiments. However, benefits, advantages, solutions to
problems, and any element(s) that may cause any benefit, advantage,
or solution to occur or become more pronounced are not to be
construed as a critical, required, or essential feature or element
of any or all the claims. As used herein, the terms "comprises,"
"comprising," or any other variation thereof, are intended to cover
a non-exclusive inclusion, such that a process, method, article, or
apparatus that comprises a list of elements does not include only
those elements but may include other elements not expressly listed
or inherent to such process, method, article, or apparatus. Also,
as used herein, the terms "coupled," "coupling," or any other
variation thereof, are intended to cover a physical connection, an
electrical connection, a magnetic connection, an optical
connection, a communicative connection, a functional connection,
and/or any other connection. When language similar to "at least one
of A, B, or C" is used in the claims, the phrase is intended to
mean any of the following: (1) at least one of A; (2) at least one
of B; (3) at least one of C; (4) at least one of A and at least one
of B; (5) at least one of B and at least one of C; (6) at least one
of A and at least one of C; or (7) at least one of A, at least one
of B, and at least one of C.
STATEMENT OF INVENTION
[0115] A commutated flux stator section, comprising a flux
concentrator, a first magnet connected to a first side of the flux
concentrator and having an outer edge parallel to, and opposite of,
the interface between the first magnet and the flux concentrator,
and a second magnet connected to a second side of the flux
concentrator opposite the first side. The second magnet may have an
outer edge parallel to, and opposite of, the interface between the
second magnet and the flux concentrator. The first magnet and the
second magnet may be magnetically oriented such that a common
magnetic pole is present on the first and second sides of the flux
concentrator. The commutated flux stator section may partially
enclose a radial section of a coil. The distance between the outer
edges of the first and second magnet may be substantially equal
throughout the commutated flux stator section partially enclosing
the coil. The outer edge of the first magnet may be parallel to the
outer edge of the second magnet. The first magnet and the second
magnet may have the same thickness. The commutated flux stator
section may comprise part of a commutated flux machine having an
axis of rotation, and the commutated flux stator section may be
tapered towards the axis of rotation. The first magnet, the second
magnet, and the flux concentrator may be individually tapered
towards the axis of rotation.
[0116] A commutated flux stator section comprising a plurality of
commutated flux stator sections assembled at least partially about
the circumference of a rotor, wherein the arc length of the
plurality of commutated flux stator sections is less than the
circumference of the rotor. A gap may be located between each of
the plurality of commutated flux stator sections. A supporting
structure may be located between one or more of the plurality of
commutated flux stator sections. A tolerancing space may be located
between at least two of the plurality of commutated flux stator
sections. The tolerancing space may be configured to facilitate
assembly of a commutated flux machine. The width of the tolerancing
space may be a function of at least one of: a manufacturing
tolerance, an on-center distance between poles in the commutated
flux machine, a switch thickness of the rotor, or the number of
poles in the commutated flux machine. The total arc length of the
plurality of commutated flux stator sections may be in the range of
about 1% to about 95% of the circumference of the rotor. A first
subset of the plurality of commutated flux stator sections may each
comprise a flux concentrator having a first polarity. A remaining
subset of the plurality of commutated flux stator sections may each
comprise a flux concentrator having a second polarity opposite the
first polarity. The rotor may be a multipath rotor.
* * * * *