Note: Descriptions are shown in the official language in which they were submitted.
CA 02812401 2014-09-02
A BRAKE ASSEMBLY FOR A VERTICAL AXIS WIND TURBINE
FIELD OF THE INVENTION
[0001] The present invention relates to wind turbines, and more particularly
to a vertical axis
wind turbine that has improved energy harnessing capabilities and wind turbine
speed
management.
BACKGROUND OF THE INVENTION
[0002] Wind turbines are used for generating electricity or otherwise
providing electrical or
mechanical power. Wind turbines rely on winds in order to impart rotation of
propellers that are
carried by a central rotor shaft. The rotor shaft is then operably coupled to
a generator in
instances where electricity is being generated or to a mechanical apparatus
when conversion of
mechanical power is desired.
[0003] Wind turbines are desirable because of low maintenance costs and the
use of available
"free" wind in order to generate clean energy. However, since wind turbines
rely on wind to
generate energy and because the speed of the wind correlates to the efficiency
of the wind
turbine, having the wind turbine rotate at an optimal speed is desired. When
the wind is blowing
at too high of a speed, the electricity generated is at a frequency in excess
of what is allowed to
be transported to the electrical grid. In order to compensate for excess wind
speed, some wind
turbines employ a mechanical or electrical brake in order to reduce the
rotation speed of the wind
turbine. These brakes are generally sufficient for controlling the speed,
however, they do not
capture the energy that would otherwise be created at high wind speeds and
instead
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convert that energy into waste heat. The lack of sufficient rotational speed
control causes the
inverter downstream of the wind turbine to shut down, thus causing downtime in
which
electricity is not being generated.
[00041 Accordingly, a need exists for a method or apparatus for
effectively monitoring the
rotation speed of a wind turbine and capturing energy that would otherwise not
be generated by
conventional devices.
SUMMARY OF THE INVENTION
1.0005] In accordance with one or more embodiments disclosed herein, a
turbine assembly is
provided.
BRIEF DESCRIPTION OF THE DRAWINGS
[00061 The foregoing summary, as well as the following detailed
description of preferred
embodiments, is better understood when read in conjunction with the appended
drawings. For
the purposes of illustration, there is shown in the drawings exemplary
embodiments; however,
the presently disclosed invention is not limited to the specific methods and
instrumentalities
disclosed. In the drawings:
[00071 FIG. I illustrates a perspective view of a wind turbine assembly
according to one or
more embodiments disclosed herein;
[0008] FIG. 2 illustrates an enlarged view of an electromagnetic assembly
and turbine
assembly according to one or more embodiments disclosed herein;
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[0009] FIG, 3 illustrates an exploded interior view of the
electromagnetic assembly
according to one or more embodiments disclosed herein;
[0010] FIG. 4 illustrates a top view of a coil mold and associated coil
packs for use with the
electromagnetic assembly according to one or more embodiments disclosed
herein;
[0011] FIG. 5 illustrates a top view of a magnet mold for use with the
electromagnetic .
assembly according to one or more embodiments disclosed herein;
[0012] FIG. 6 illustrates a top view of a magnet assembly for use with
the electromagnetic
assembly according to one or more embodiments disclosed herein;
[0013] FIG. 7 illustrates a layout of coil packs to magnet ratio
according to one or more
embodiments disclosed herein;
[0014] FIG. 8 illustrates a coil mold having one or more vents defined
between adjacent coil
recesses in which coil packs are received according to one or more embodiments
disclosed
herein;
[0015] FIG. 9 illustrates the wind turbine assembly shown in which
support arms are shown
in a position where the wind turbine assembly is being readied for transport
according to one or
more embodiments disclosed herein;
[00161 FIG. 10 illustrates a schematic of a system diagram according to
one or more
embodiments disclosed herein;
[00171 FIG. 11 illustrates a flow chart depicting one or more methods
disclosed herein;
[0018] FIG 12. illustrates a brake assembly for controlling the rotation
speed of the turbine
assembly disclosed herein; and
[0019] FIGS. 13 through 15 illustrate the brake assembly in various
braking positions.
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DESCRIPTION
[0020] The presently disclosed invention is described with specificity to
meet statutory
requirements. However, the description itself is not intended to limit the
scope of this patent.
Rather, the inventors have contemplated that the claimed invention might also
be embodied in
other ways, to include different steps or elements similar to the ones
described in this document,
in conjunction with other present or future technologies.
[0021] Disclosed herein is a wind turbine that is generally designated
10. The one or more
embodiments illustrated includes a vertical axis wind turbine 10, though
horizontal or non-
orthogonal axis wind turbines may be equally advantageously equipped with the
one or more
improvements disclosed herein. Wind turbine 10 includes a plurality of sails
with each being
indicated generally by the numeral 16. The wind turbine 10 includes a central
post 12 for
supporting the sails. Central post 12 may also include a support 13 for
supporting the post 12
about a ground surface. The wind turbine 10 includes a generator assembly 14
that is configured
for generating energy with a rotor/stator assembly that will be further
described herein and for
controlling the rotation speed of the wind turbine. Any appropriately
configured generator
assembly may be further used in addition to the generator assembly 14 for
generating electricity.
Each sail 16 is operatively connected to drive the generator assembly 14
through a series of arms
18A. It will be appreciated that as the sails 16 are driven by wind, the
turning or movement of
the sales will in turn cause the generator assembly 14 to be driven, which in
turn results in the
generation of electrical energy. Control of the rotation speed of the turbine
10 and thus the
generator assembly 14 will be further discussed herein.
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[0022] An enlarged view of the generator assembly 14 and portion of
turbine 10 is illustrated
in FIG. 2. The generator assembly 14 defines a support 19 on each of the top
and bottom
surfaces thereof that receives each of arms 18A. In this manner, the arms 18A
extend in a
generally upwardly diagonal direction and a generally downwardly diagonal
direction from the
generator assembly 14. A pin 21 is received through an opening defined in each
support 19 and
engagebly receives an end of each of the arms 18A. In this manner, arms 18A
are capable of
upward and downward movement with sail 16 and are replaceable or removable if
desired.
[0023] Generator assembly 14 may include a housing 13 that has an
identical top and bottom
portion 23 and 25 that maintains the internal components in precise
arrangements. In one
embodiment, the design allows for the attachment of ten separate arms 18A
between the
generator assembly 14 and sails 16, and thus five sails 16. In one or more
embodiments, each
arm 18A is positioned at an even 72 degrees apart from each other arm 18A and
thus provides
maximum stress distribution amongst the joints. The bolt patterns may be
identical through the
internal sections of the generator assembly 14 and the top and bottom cast
will lock the separate
pieces into one unit. The straight edges around the cast have been reduced at
least to a 1/8"
chamfer (*cc) to reduce the structural stresses on the unit.
[0024] While the turbine assembly 10 is shown with five sails 16, in
appropriate
embodiments it may be provided with more or less sails 16. Additionally, while
the turbine
assembly 10 is shown having arms 18A originating from the generator assembly
14, only one
arm or multiple arms of a different shape, configuration, and size may be
employed if desired.
[0025] Arm 18A allows for a displacement to an angle of 90 degrees for
portability. The
lateral walls of the arm 18A have been tapped with one half inch holes to
allow the positioning
of the lock pin which will help hold the arms 18A in position.
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100261 The wind turbine assembly 10 described herein is a vertical axis
wind generator. In
one or more embodiments, the turbine assembly 10 may be rated to produce 10KW.
The turbine
assembly 10 is designed to be modular, thereby avoiding major structural
alteration to step up or
down to various capacity generators. If desired, one or more turbines 10 may
be employed in
series or parallel to reach a desired energy output. Additionally, in one or
more embodiments,
multiple generator assemblies 14 may be employed on one central shaft 12 in
order to reach a
desired signal output.
100271 As illustrated more closely in FIG. 3, the generator assembly 14
includes a stator 22
and a rotor 24. As illustrated more closely in FIG. 4 and with additional
reference to FIGS. 5
through 8, the stator 22 includes a coil mold 34 that has the one or more coil
assemblies 27
carried therein. The coil pack assemblies 27 will be described further herein.
[00281 As illustrated more closely in FIG. 5, the rotor 24 includes a
plate 36 to which a
magnet ring 30 illustrated in FIG 6 is provided about. The magnet ring 30 that
may include a
plurality of spaced-apart magnets 32. The magnets 32 will be described further
herein.
[00291 In operation, the thrust generated by the sails 16 in a wind
environment drives the
rotor 24 around the stator 22 inducing a current in the coil assembly coil
mold 34 and thereby
generating power. Stator 22 is configured to be stationary while rotor
assembly 24 rotates about
the stator 22. This is accomplished because plate 33 is attached directly to
the housing 13 where
the coil mold 34 is fixedly attached to the center shaft 12. In appropriate
embodiments, stator 22
may be configured for rotating about rotor assembly 24.
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[0030] in one or more embodiments, there are provided twenty seven (27)
coil pack
assemblies 27 that are circumferentially spaced-apart at an angle of 13.3
degrees from each other
as illustrated more closely in FIG. 4 and FIG. 7. The angle 13.3 degrees has
been advantageously
determined to maintain a 3:4 coil assembly coil mold 34 to magnet 30 ratio
which has been
found to minimize the conversion losses by producing extremely clean 3-phase
alternating
current (AC). This is advantageously depicted in the overhead, exploded view
of FIG. 7 in which
the coil assemblies 27 and magnets 30 are depicted. The coil pack assemblies
27 are wired using
the star convection to maximize voltage at low RPM. The coil pack assemblies
27 have also been
designed to be able to stack over one another thereby making the whole unit
modular. The coils
pack assemblies 27 are divided into three separate phases each consisting of
two 12 gauge
windings and seven 16 gauge windings to maximize voltage. The separate phases
may also be
routed through a capacitor circuit to regulate the induction shocks. A
capacitor-diode interface
may be provided between the coils 27 in order to provide a check on residual
harmonics
backtracking through the generator assembly 14 and thus dissipate shocks or
vibrations.
[00311 In one or more embodiments, the magnet assembly 30 and magnets 32
are laid out as
36 Neodymium permanent magnets 30 held at an even 10 degrees apart from each
other as
illustrated in FIG. 6. This angle maintains the 3:4 coil:magnet ratio as
disclosed herein. The
magnets 30 have been wedged towards the center shaft 12 to align the fields
with conductors of
the coils 27 to promote magnetic induction.
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[00321 Coil mold 34 is provided around the coil pack assemblies 27 to
help position the coil
pack assemblies 27 within acceptable tolerances. The coil mold 34 may define
one or more vents
29 for allowing the ventilation of heat generated during the induction cycles
between adjacent
coil pack assembly housings 28 as illustrated in FIG. 8. The added ventilation
will help maintain
the temperature of the stator 22 thereby improving overall efficiency and
power generation. The
coil mold 34 may also be lined with sheets of ferrous metal to guide the flux
lines and thereby
attain maximum saturation of coils. In one or more experiments, both the
ventilation and ferrous
material dramatically improve generation potential.
[0033] A coil plate 38 may be provided and may attach to the center shaft
12. The coil plate
38 may be made from aluminum. The coil plate 38 is bolted on to the coil mold
34 to minimize
the torsional loads acting at the joints of the mold 34. This may
advantageously reduce or even
out vibrations and improve the life of the stator 22 as a whole.
1.0034] A magnet mold 36 may be provided to align the opposite poles of
the magnets 30 on
to the magnet plate 32. The magnet mold 36 may be provided to stabilize the
opposing fields
generated by the coils 27 and coil mold 34 and will induced current flows
through circuitry
operably coupled with the generator assembly 14. The magnet mold 36 is
connected to the outer
cast of housing 13 and spins along with the rest of the generator assembly 14.
1100351 A magnet plate may also be provided. The magnet plate may be a
steel plate that is
used to align the magnets and fix them to the rest of the structure before
locking the magnet ring
in a mold. The plates provide shielding to the magnetic pole opposite the coil
pack assemblies 26
and plate 27 thereby strengthening the adjacent poles and boosting the power
generation.
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[0036] Vertical axis wind turbines are designed to be most efficient at
lower RPM levels
when compared to horizontal axis wind turbines. The generator assembly 14 has
been designed
with an electromagnetic and an optional frictional brake to control the RPM
level and provide
reliable power. If necessary, assembly 10 is further in communication with a
dump load to
which excess energy can be transferred to in order to raise the internal
resistance of the generator
assembly 14 and cease movement thereof.
[0037] Turning to the sails 16, there is a plurality of sails shown in
the embodiment of FIG.
I. In the case of the embodiment shown in FIG. 1, there are eight equally
spaced sails 16. The
number of sails can vary depending upon application and specific design.
[00381 Also disclosed is a brake assembly 50 illustrated in FIG. 12. The
brake assembly 50
may be provided at any point along shaft 12 of the wind turbine 10. The brake
assembly 50 may
include an actuator 52. Actuator 52 is illustrates as an electrically powered
actuator having a
magnetic translation mechanism and plunger, though any appropriately provided
actuator may
function. Actuator 52 is configured for being in contact with plate 54 which
is then connect
against shaft or cylinder 56. Shaft 56 is connected to the stator shaft or
shaft 12 and therefore
has no axial rotation. A magnet assembly 60 may be provided along a plate 62
that is coupled to
a cylinder or shaft 64. This shaft 64 is operably coupled with sails 16 and is
configured for
rotation during rotation of the turbine assembly 10. This causes the magnet
assembly 60 to also
rotate with rotation of the turbine assembly 10. The actuator 52 then
communicates with a
control module 112 that controls the actuator to translate plate 62 into
closer-spaced or further-
spaced arrangement relative to the magnet assembly 60. Control module 112 will
be discussed
with further reference to FIG. 11.
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[0039] As plate 62 passes into closer-spaced arrangement relative to
magnet assembly 60,
eddy currents are created within plate 62 due to rotation of the magnet
assembly 60 with rotation
of turbine 10. This eddy current then creates a magnetic field which usually
operates in the
reverse direction of rotation of the turbine assembly 10. The brake assembly
50 is thus
configured to impart retarding forces on shaft 12 in order to reduce the
turbine assembly 10
speed to an acceptable level for most efficient power production.
[0040] The actuator 52 may be coupled via control module 112 with an
inverter downstream
of the turbine assembly 10 or other signal monitoring/conditioning device and
is configured to
determine the speed of the turbine assembly 10 based on the measurements of
the inverter as will
be described with further reference to FIG. 10. Additionally, other signal
conditioners instead of
an inverter may be employed, with similar monitored data from the signal
conditioner being used
by control module 112 to determine the rotational speed of the turbine
assembly 10.
10041] FIGS. 13 through 15 represent various open and closed positions
of the braking
assembly 50 (with the actuator not shown for clarity purposes). FIG. 13
illustrates the plate 66
being relatively spaced-apart from magnet assembly 60. In this arrangement,
the distance
between plate 66 and magnet assembly 60 is such that no interaction of eddy
currents
therebetween is likely to create a retarding force to the turbine assembly 10.
[0042] FIG. 14 illustrates the plate 66 being closer-spaced than that
which is shown in FIG.
14. In this spacing, the distance between plate 66 and magnet assembly 60 may
be such that a
moderate amount of retarding forces are created by eddy currents between plate
66 and magnet
assembly 60 to thereby reduce the rotational speed of turbine assembly 10.
[00431 FIG. 15 illustrates plate 66 being closely-spaced to magnet
assembly 60. In this
spacing, the distance between plate 66 and magnet assembly 60 is such that a
significant amount
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of retarding forces are created by eddy currents between plate 66 and magnet
assembly 60 to
thereby reduce the rotational speed of or entirely stop rotation of turbine
assembly 10.
[00441 Each sail 16 comprises a generally J-shaped structure that is
elongated and, as
illustrated in FIG. 1 in a typical application, the .1-shaped sail is
vertically oriented.
[0045] The J-shaped sail 16 includes a leading edge or nose section 18.
This section is
curved and forms an elongated cup along the leading edge of the sale 16. As
illustrated in the
drawings, the leading edge 18 forms an elongated vertical trough.
[00461 Extending from the leading edge or nose section 18 is a back which
is generally
planar in design. The back extending from the nose section 18 terminates in a
trailing edge.
There is a plurality of gussets or struts that are spaced apart and which
extend from the interior of
the nose section 18 to a point just forwardly of the trailing edge. The
function of the gussets or
struts is to reinforce the sail 16 and to make the sail structurally sound.
[0047] The sail 16 can be constructed of various materials such as
aluminum, fiberglass,
plastic or any other suitable material. The thickness of the sail proper, that
is the nose section 18
and the back, in atypical application is approximately 1/8 of an inch to
approximately 1/4 of an
inch. The depth of the curved nose section 18 in one embodiment may be between
about 4 and
about 6 inches measured radially outwardly from the back 20. The height of the
sail 16, as
oriented in FIG. I, in a typical application would be about eighteen feet.
However, it is
appreciated that these dimensions are for exemplary purposes and that the
dimensions of the sail
18 can vary over a significant range depending upon application.
[0048] Note that the sail 18 includes two sides, a face or outer side and
a back side. The face
side would face oncoming wind and the oncoming wind would impinge upon the
upper side of
the sail 18. The back side of the sail 16 is the lower side of the sail
structure. Thus is it
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appreciated that oncoming wind will impinge upon the face side of the sail and
will tend to move
along the face side and impinge into the concave cavity formed by the curved
nose section 18.
This will enable the sail structure to efficiently catch the wind and turn the
oncoming wind into
energy. Then, as viewed in HG. 1, on the back side of the turbine, that is the
side opposite the
wind direction, the back side of the back would face the oncoming wind and
will effectively
reduce resistance or drag.
[0049] The turbine 10 illustrated in FIG. 1 is configured for turning
clockwise. Note that the
sails 16 are slightly angled with respect to the axis of the arms 18A. This
angle can vary but in
one embodiment, but, in one or more embodiments, the back of each sail is
angled at an angle of
approximately 7% off the axis of the adjoining arm 18A. That is the nose 18 of
each sail is
slightly positioned inwardly.
[0050] There are many advantages to the vertical axis type wind turbine
of the present
invention. One of the advantages revolves around the J-shaped sails and their
ability to
efficiently catch the wind and turn the force of the wind into efficient
energy. More particularly,
the J-shaped sails are effective in responding to low wind conditions and yet
producing cost
effective energy in low wind environments. Moreover, the J-shaped sails are
designed to be
relatively light but yet structurally sound.
[0051] One or more advantageous aspects of the one or more disclosed
turbines 10 is the
ability for the turbine 10 to be easily transported. Each of the upper half of
arms 18A are
configured for being, pivoted about support 19 until they are pointed in a
generally upwards
direction and perpendicular to a ground surface. In FIG. 9, three of the five
arms 19A on the
upper half are shown being pivoted fully upright. Each of the lower half of
arms 18A are
configured for being pivoted about support 19 until they are pointed in a
generally downwards
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direction and perpendicular to a ground surface. In this manner, the turbine
10 is easily portable
by removing the sails and pivoting the arms 18A until the turbine assembly
makes a generally
cylindrical structure, which can then be bound or otherwise secured and
transported.
[0052] A system 100 is illustrated in the schematic of FIG. 10 that
includes a wind turbine 10
disclosed herein. The system 100 may include a control module 112 that is
configured to control
the wind turbine 10, specifically the brake assembly 50 in order to adjust the
rotational speed of
the wind turbine 10 to desired levels. This adjustment may be accomplished by
actuation of the
actuator 52 to impart greater braking forces by the brake assembly 50 by
varying the distance
between plate 66 and magnet assembly 60. Control module 112 may also be
configured to, for
example, apply an additional external braking assembly, if one is provided, to
further slow down
the speed of the turbine assembly 10. Additionally, control module 112 may be
further
configured to actuate one or more switches in order to, for example, control
current flow to an
external storage source such as battery 116 or electrical grid 120. A signal
conditioner 114, such
as a power inverter or the like, may be provided for further conditioning of
electricity before it is
passed to the battery 116 or grid 120. The control module 112 is configured to
communicate
with the signal conditioner 114 in order to determine the rotational speed of
the turbine 10. In
this manner, the signal passing through conditioner 114 can be converted into
a rotational speed
of the turbine 10 and the control module 112 can then determine if adjustments
to the rotation
speed of turbine 10 are needed.
[00531 One or more advantageous aspects of the subject matter disclosed
herein includes that
the turbine assembly 10 may be provided with bearings between the generator
assembly 14 and
central post 12 such that parasitic rotational losses are minimized.
Additionally, the 3:4 coil to
magnet ration disclosed herein is especially advantageous because it has been
determined, in one
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or more experiments, that this ratio produces electricity having a general
consistency with the
electrical grid and is thus suitable for return to the electric grid. Due to
the combination of
capturing energy in order to effectuate braking of the turbine assembly 10
when rotating at
beyond desired speeds, turbine assembly 10 has very minimal losses due to
braking and parasitic
losses.
[00541 One or more methods 200 are depicted in FIG. 11 and generally
designated 200. The
one or more methods may include determining 202 a characteristic of energy at
the downstream
inverter 202. The one or more methods 200 may include 204 based on the
determined
characteristic, determining a rotational speed of the turbine assembly. The
one or more methods
200 may include controlling 206 a brake assembly, such as brake assembly 50,
to produce a
retarding force corresponding to a desired rotational speed of the turbine
assembly based on the
determined speed.
[0055] The present invention may, of course, be carried out in other ways
than those
specifically set forth herein without departing from essential characteristics
of the invention. The
present embodiments are to be considered in all respects as illustrative and
not restrictive, and all
changes coming within the meaning and equivalency range of the appended claims
are intended
to be embraced therein.
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