U.S. patent application number 15/379819 was filed with the patent office on 2017-05-25 for asymmetrical unipolar flame ionizer using a step-up transformer.
The applicant listed for this patent is CLEARSIGN COMBUSTION CORPORATION. Invention is credited to IGOR A. KRICHTAFOVITCH, CHRISTOPHER A. WIKLOF.
Application Number | 20170146234 15/379819 |
Document ID | / |
Family ID | 55218180 |
Filed Date | 2017-05-25 |
United States Patent
Application |
20170146234 |
Kind Code |
A1 |
KRICHTAFOVITCH; IGOR A. ; et
al. |
May 25, 2017 |
ASYMMETRICAL UNIPOLAR FLAME IONIZER USING A STEP-UP TRANSFORMER
Abstract
A system and method for electrically charging a combustion flame
with a power supply.
Inventors: |
KRICHTAFOVITCH; IGOR A.;
(KIRKLAND, WA) ; WIKLOF; CHRISTOPHER A.; (EVERETT,
WA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
CLEARSIGN COMBUSTION CORPORATION |
SEATTLE |
WA |
US |
|
|
Family ID: |
55218180 |
Appl. No.: |
15/379819 |
Filed: |
December 15, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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PCT/US2015/040277 |
Jul 14, 2015 |
|
|
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15379819 |
|
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62030960 |
Jul 30, 2014 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F23D 14/84 20130101;
F23N 5/123 20130101; F23C 99/001 20130101 |
International
Class: |
F23C 99/00 20060101
F23C099/00 |
Claims
1. A system for electrically controlling a combustion flame,
comprising: a burner configured to generate the combustion flame,
wherein the combustion flame includes a resistance and a
capacitance; an ionizer positioned proximate to the burner to
supply ions of a first polarity to the combustion flame to charge
the capacitance of the combustion flame to one or more voltage
levels; and a power supply coupled to the ionizer and configured to
provide an output voltage signal of the first polarity to the
ionizer to excite the ionizer to supply the ions of the first
polarity to the combustion flame, wherein the power supply includes
a transformer and an output dampener operatively coupled in
parallel to the transformer, wherein the output dampener suppresses
a second polarity of the output voltage signal to limit delivery of
ions of the second polarity to the combustion flame by the
ionizer.
2. The system of claim 1, wherein the capacitance is between three
and five picofarads (3-5 pF).
3. The system of claim 1, wherein the ionizer is positioned at
least 1 inch away from combustion flame.
4. The system of claim 1, wherein the first polarity is positive
and the second polarity is negative.
5. The system of claim 1, wherein the first polarity is negative
and the second polarity is positive.
6. The system of claim 1, wherein the ionizer includes an emitting
electrode.
7. The system of claim 6, wherein the ionizer includes a collecting
electrode.
8. The system of claim 7, wherein the emitting electrode and the
collecting electrode are positioned on opposite sides of the
combustion flame to direct a flow of the ions into the combustion
flame.
9. The system of claim 7, wherein the collecting electrode is the
burner that is configured to generate the combustion flame.
10. The system of claim 1, wherein the ionizer is configured to
supply the ions upon excitation with approximately 4 kV.
11. The system of claim 1, wherein output voltage signal of the
first polarity is a square-wave pulse.
12. The system of claim 1, wherein the power supply includes a
primary winding and a secondary winding.
13. The system of claim 12, wherein the output dampener is
electrically coupled in parallel to the primary winding.
14. The system of claim 12, wherein the output dampener is
electrically coupled in parallel to the secondary winding.
15. The system of claim 12, wherein the output dampener includes a
resistor.
16. The system of claim 15, wherein the output dampener includes a
diode electrically coupled in series to the resistor.
17. The system of claim 16, wherein the diode is oriented to allow
current to continue flowing through the primary winding of the
transformer after power is removed from the primary winding.
18. A system for electrically controlling a combustion flame,
comprising: a first power supply configured to generate a first
output voltage pulse of a first polarity in excess of a first
predetermined threshold, wherein the first power supply includes a
first step-up transformer, wherein the first power supply includes
a first output dampener coupled to the first step-up transformer
and configured to at least partially suppress a second output
voltage pulse of a second polarity to prevent the second output
voltage pulse from exceeding a second predetermined threshold; a
second power supply configured to generate a third output voltage
pulse of the first polarity in excess of the first predetermined
threshold, wherein the second power supply includes a second
step-up transformer, wherein the second power supply includes a
second output dampener coupled to the second step-up transformer
and configured to at least partially suppress a fourth output
voltage pulse of the second polarity to prevent the fourth output
voltage pulse from exceeding the second predetermined threshold,
wherein the second polarity is different than the first polarity; a
first ionizer operatively coupled to the first power supply and
configured to supply first ions of the first polarity to a
combustion flame to charge the combustion flame, in response to
receipt of the first output voltage pulse; a second ionizer
operatively coupled to the second power supply and configured to
supply second ions of the first polarity to the combustion flame to
charge the combustion flame, in response to receipt of the third
output voltage pulse; and a controller communicatively coupled to
the first power supply and to the second power supply to
selectively cause the first ionizer and the second ionizer to
supply the first ions and the second ions to the combustion
flame.
19. The system of claim 18, wherein the first predetermined
threshold is approximately 4 kV and the second predetermined
threshold is approximately -4 kV.
20. The system of claim 18, wherein the first polarity is positive
and the second polarity is negative.
21. The system of claim 18, wherein the controller time-multiplexes
operation of the first power supply and the second power supply so
that the first output voltage pulse and the third output voltage
pulse are generated sequentially.
22. The system of claim 18, wherein the first output dampener
includes a first resistor and a first diode, wherein the first
diode is oriented to enable a first current to continue flowing
through a primary winding of the first transformer, wherein the
second output dampener includes a second resistor and a second
diode, wherein the second diode is oriented to enable a second
current to continue flowing through a primary winding of the second
transformer.
23. The system of claim 18, wherein the first ionizer includes a
first emitter electrode and a first collector electrode, wherein
the second ionizer includes a second emitter electrode and a second
collector electrode.
24. The system of claim 23, wherein the first emitter electrode and
the first collector electrode are positioned on first opposite
sides of the combustion flame, and the second emitter electrode and
the second collector electrode are positioned on second opposite
sides of the combustion flame.
25. The system of claim 18, further comprising: a third power
supply configured to generate a fifth output voltage pulse of the
second polarity in excess of the second predetermined threshold,
wherein the third power supply includes a third step-up
transformer, wherein the third power supply includes a third output
dampener coupled to the third step-up transformer and configured to
at least partially suppress a sixth output voltage pulse of the
first polarity to prevent the sixth output voltage pulse from
exceeding the first predetermined threshold; and a third ionizer
operatively coupled to the third power supply and configured to
supply third ions of the second polarity to the combustion flame to
charge the combustion flame, in response to receipt of the fifth
output voltage pulse, wherein the controller is configured to time
multiplex operation of the third power supply to selectively cause
the third power supply to generate the fifth output pulse to supply
the combustion flame with the third ions of the second
polarity.
26. The system of claim 18, wherein the combustion flame includes a
resistance and a capacitance, wherein the capacitance is
approximately 3-5 pF.
27. A method for electrically controlling a combustion flame,
comprising: generating, with a power supply, a voltage signal
having a first portion of a first polarity and having a second
portion of a second polarity, wherein the first portion of the
voltage signal is greater than or equal to a first predetermined
threshold; suppressing the second portion of the voltage signal,
with an output dampener, to prevent the second portion of the
voltage signal from exceeding a second predetermined threshold, by
reducing a rate of current change in a transformer of the power
supply, while generating the second portion of the voltage signal;
and generating ions of the first polarity, with an ionizer, in
response to receiving the first portion of the voltage signal,
wherein generating ions includes supplying the ions to a combustion
flame to charge the combustion flame to a voltage to alter one or
more characteristics of the combustion flame.
28. The method of claim 27, wherein the combustion flame includes a
capacitance.
29. The method of claim 28, wherein the capacitance is between
three and five picofarads (3-5 pF).
30. The method of claim 27, wherein the first polarity is positive
and the second polarity is negative.
31. The method of claim 27, wherein the first predetermined
threshold is 4 kV and the second predetermined threshold is -4
kV.
32. The method of claim 27, wherein the output dampener includes a
resistor and a diode coupled in series, wherein the output dampener
is coupled in parallel to the transformer.
33. The method of claim 27, wherein the transformer includes a
primary winding and a secondary winding and the output dampener is
coupled to the primary winding.
34. The method of claim 27, wherein suppressing the second portion
of the voltage signal to prevent the second portion of the voltage
signal from exceeding the second predetermined threshold prevents
the ionizer from generating ions of the second polarity.
35. The method of claim 27, wherein the first predetermined
threshold is a corona onset voltage for a fluid that is proximate
to the ionizer.
36. The method of claim 27, wherein the second predetermined
threshold is a negative corona onset voltage.
37. The method of claim 27, wherein the ionizer includes an emitter
electrode and a collector electrode.
38. The method of claim 27, wherein the ionizer includes an emitter
electrode and the combustion flame functions as a collector
electrode.
39. The method of claim 27, wherein the ionizer includes an emitter
electrode and a burner is coupled to the power supply to function
as a collector electrode, wherein the burner generates the
combustion flame.
40. The method of claim 27, wherein the power supply generates the
voltage signal in response to receiving a command signal from a
controller.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a U.S. Continuation Application
which claims priority benefit under 35 U.S.C. .sctn.120 (pre-AIA)
of co-pending International Patent Application No.
PCT/US2015/040277, entitled "ASYMMETRICAL UNIPOLAR FLAME IONIZER
USING A STEP-UP TRANSFORMER," filed Jul. 14, 2015 (docket number
2651-220-04); which application claims priority benefit from U.S.
Provisional Patent Application No. 62/030,960, entitled
"ASYMMETRICAL UNIPOLAR FLAME IONIZER USING A STEP-UP TRANSFORMER,"
filed Jul. 30, 2014 (docket number 2651-220-02); each of which, to
the extent not inconsistent with the disclosure herein, is
incorporated herein by reference.
SUMMARY
[0002] According to an embodiment, a system for electrically
controlling a combustion flame may include a burner configured to
generate the combustion flame. The combustion flame includes a
resistance and a capacitance. The system may include an ionizer
positioned proximate to the burner to supply ions of a first
polarity to the combustion flame to charge the capacitance of the
combustion flame to one or more voltage levels. The system may
include a power supply coupled to the ionizer and configured to
provide an output voltage signal of the first polarity to the
ionizer to excite the ionizer to supply the ions of the first
polarity to the combustion flame. The power supply may include a
transformer and an output dampener operatively coupled in parallel
to the transformer. The output dampener can suppress a second
polarity of the output voltage signal to limit delivery of ions of
the second polarity to the combustion flame by the ionizer.
[0003] According to an embodiment, a system for electrically
controlling a combustion flame may include a first power supply
configured to generate a first output voltage pulse of a first
polarity in excess of a first predetermined threshold. The first
power supply may include a first step-up transformer. The first
power supply may include a first output dampener coupled to the
first step-up transformer and configured to at least partially
suppress a second output voltage pulse of a second polarity to
prevent the second output voltage pulse from exceeding a second
predetermined threshold. The system may include a second power
supply configured to generate a third output voltage pulse of the
first polarity in excess of the first predetermined threshold. The
second power supply may include a second step-up transformer. The
second power supply may include a second output dampener coupled to
the second step-up transformer and configured to at least partially
suppress a fourth output voltage pulse of the second polarity to
prevent the fourth output voltage pulse from exceeding the second
predetermined threshold. The second polarity may be different than
the first polarity. The system may include a first ionizer
operatively coupled to the first power supply and configured to
supply first ions of the first polarity to a combustion flame to
charge the combustion flame, in response to receipt of the first
output voltage pulse. The system may include a second ionizer
operatively coupled to the second power supply and configured to
supply second ions of the first polarity to the combustion flame to
charge the combustion flame, in response to receipt of the third
output voltage pulse. The system may include a controller
communicatively coupled to the first power supply and to the second
power supply to selectively cause the first ionizer and the second
ionizer to supply the first ions and the second ions to the
combustion flame.
[0004] According to an embodiment, a method for electrically
controlling a combustion flame may include generating, with a power
supply, a voltage signal having a first portion of a first polarity
and having a second portion of a second polarity. The first portion
of the voltage signal is greater than or equal to a first
predetermined threshold. The method may include suppressing the
second portion of the voltage signal, with an output dampener, to
prevent the second portion of the voltage signal from exceeding a
second predetermined threshold, by reducing a rate of current
change in a transformer of the power supply, while generating the
second portion of the voltage signal. The method may include
generating ions of the first polarity, with an ionizer, in response
to receiving the first portion of the voltage signal. Generating
ions can include supplying the ions to a combustion flame to charge
the combustion flame to a voltage to alter one or more
characteristics of the combustion flame.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] FIG. 1 is a block diagram of a system for applying voltage
to a combustion flame, according to an embodiment.
[0006] FIG. 2 is a graphical illustration of a voltage suppression
function of the system for applying voltage to a combustion flame,
according to an embodiment.
[0007] FIG. 3 is a block diagram of a system for applying voltage
to a combustion flame, according to an embodiment.
[0008] FIG. 4 is a block diagram of a system for applying voltage
to a combustion flame, according to an embodiment.
[0009] FIG. 5 is a flow diagram of a method for electrically
controlling a combustion flame, according to an embodiment.
DETAILED DESCRIPTION
[0010] In the following detailed description, reference is made to
the accompanying drawings, which form a part hereof. In the
drawings, similar symbols typically identify similar components,
unless context dictates otherwise. Other embodiments may be used
and/or other changes may be made without departing from the spirit
or scope of the disclosure.
[0011] Electrodynamic combustion control may be used to control
and/or vary characteristics of a combustion flame or combustion
reaction. The application of a voltage, charge, current, and/or
electric field to a combustion flame may be used to improve heat
distribution of the flame, to stabilize the flame, and/or to
prevent flame impingement. The application of electrodynamic
combustion control may also improve the energy efficiency, shape,
and/or heat transfer of the flame.
[0012] The inventors have identified several issues that may be
associated with applying a high-power voltage to a combustion
flame. For example, if an electrode of a power supply is directly
coupled or inserted within a combustion flame, and the combustion
flame inadvertently contacts a grounded conductor or a grounded
housing, the combustion flame can electrically couple the power
supply to grounded contact point and potentially damage the power
supply.
[0013] Another example of an issue identified by the inventors is
that traditional power supply configurations may be limited to
charging a load with the voltage that is only as high as the power
supply can generate. Accordingly, a power supply configuration that
could charge a load to a voltage that is higher than the capacity
of the power supply may enable the power supply to be designed or
built to lower voltage specifications than the desired load
voltage.
[0014] Disclosed herein are methods and systems of applying a
unipolar charge to a combustion flame. The methods and systems
enable physical isolation between the power supply and the
combustion flame while enabling the power supply to charge the
combustion reaction to higher voltages than the power supply itself
can output.
[0015] FIG. 1 illustrates an electrodynamic flame control system
100 for charging a combustion flame to one or more voltage levels,
according to one embodiment. As used herein "electrodynamic flame
control" may refer to the application of a voltage, charge,
current, and/or electric field to control combustion flame behavior
and to improve heat distribution in a combustion volume. In one
embodiment, the application of the charge or current to the
combustion flame includes supplying ions or electrons to the
combustion flame with an ionizer. The electrodynamic flame control
system 100 includes a power supply 102 and an ionizer 104 for
charging a combustion flame 106 to one or more voltage levels,
according to one embodiment.
[0016] The power supply 102 may be configured to charge the
combustion flame 106 to one or more voltage levels without
physically contacting, connecting to, or coupling with the
combustion flame 106, according to one embodiment. Physically
decoupling the power supply 102 from the combustion flame 106 can
protect the power supply 102 from inadvertent damage, e.g.,
short-circuiting through the combustion flame 106 to ground. The
power supply 102 may be electrically coupled to the ionizer 104 to
charge the combustion flame 106 to one or more voltage levels. In
one embodiment, the ionizer 104 is disposed or positioned proximate
to, but external to, the combustion flame 106 so that a physical
connection or coupling is absent between the power supply 102 and
the combustion flame 106. The power supply 102 can be configured to
supply the ionizer 104 with a high-power voltage, e.g., greater
than or equal to approximately 4 kilovolts ("kV"), to enable the
ionizer 104 to ionize fluids that are proximate to or adjacent to
the ionizer 104 and/or that are proximate to the combustion flame
106. According to one embodiment, the power supply 102 can be
configured to supply the ionizer 104 with a high-power voltage that
is less than or equal to a breakdown voltage, e.g., +/-10 kV, of
the fluid that is to be ionized. The corona onset voltage can be
+/-4 kV for some fluids. In one embodiment, the power supply 102
can be configured to supply the ionizer 104 with a high-power
voltage that is greater than or equal to the corona onset voltage
of a fluid and that is less than or equal to a breakdown voltage
for the fluid. By supplying ions to the combustion flame 106,
rather than directly charging the combustion flame 106 with a
voltage, the power supply 102 can selectively charge the combustion
flame 106 to one or more voltage levels without physically
contacting, connecting to, or coupling with the combustion flame
106.
[0017] The ionizer 104 can be implemented using any one of a number
of ionizer configurations to supply ions to the combustion flame
106 in order to charge the combustion flame 106 to one or more
voltage levels, according to one embodiment. For example, the
ionizer 104 can include one or more electrodes, one or more fluid
displacement mechanisms, one or more fluid supply mechanisms,
and/or one or more fluid delivery mechanisms, according to various
embodiments. For example, the one or more electrodes can include a
single emitter electrode, an emitter electrode and a collector
electrode, or multiple emitter electrodes and multiple collector
electrodes. Other names for the electrodes can include corona
electrode, counter electrode, target electrode cathode, anode, or
the like. In one embodiment, the ionizer 104 includes a single
emitter electrode and uses the combustion flame 106 or a burner 108
as a collector electrode. When the voltage between the emitter
electrode and collector electrode of the ionizer 104 approaches,
equals, and/or exceeds the corona onset voltage, e.g., 4 kV, the
carrier fluid molecules that are proximate to or in the vicinity of
the emitter electrode begin ionizing. The ionizer 104 can be
configured to provide a strong ionic stream, i.e., an ionic
current, from just a few kilovolts of voltage. The ions can have a
charge that is of the same polarity as the emitter electrode, and
the ions are repulsed from the emitter electrode in the direction
of the combustion flame 106 and/or in the direction of the
collector electrode. Because the combustion flame 106 includes a
resistance 110 (e.g., 3-4 megaohms) and a capacitance 112 (e.g.,
3-5 picofarads "pF"), receipt of cations or anions (i.e., positive
or negative charged ions) by the combustion flame 106 results in an
increase in voltage or electrical potential in the combustion flame
106.
[0018] The voltage of the combustion flame 106 that results from
injection of ions can be characterized, described, or defined in
terms of charge, capacitance, and/or current. The voltage across
the capacitance 112 of the combustion flame 106 can be expressed in
terms of charge, capacitance, and/or current as:
V=Q/C (Equation 1);
and
V=(I*t)/C (Equation 2),
[0019] where V is voltage,
[0020] Q is charge,
[0021] C is capacitance,
[0022] I is current, and
[0023] t is time.
Equation 1simply states that the voltage is proportional to the
charge Q stored by a capacitance C, so increasing charge on a fixed
capacitance will proportionally increase the voltage across a
capacitance. Similarly, Equation 2 expresses charge as a product of
current and time and shows that providing current, such as a stream
of ions, to a fixed capacitance for a period of time will also
increase the voltage across the capacitance. Accordingly, by
configuring the power supply 102 and the ionizer 104 to supply the
combustion flame 106 with ions, i.e., charge, the power supply 102
and the ionizer 104 can selectively charge the combustion flame 106
to one or more voltage levels, according to various
embodiments.
[0024] The power supply 102 may be configured to excite the ionizer
104 to generate unipolar ions, according to one embodiment. If the
power supply 102 provides or excites the ionizer 104 with a voltage
that is equal to or in excess of a positive corona onset voltage,
the ionizer 104 generates positive ions. However, if the power
supply 102 provides the ionizer 104 with a voltage that is equal to
or less than a negative corona onset voltage, the ionizer 104
generates negative ions. Therefore, if the power supply 102 causes
the ionizer 104 to supply the combustion flame 106 with positive
ions, but then causes the ionizer 104 to supply the combustion
flame 106 with negative ions, the power supply 102 may
inadvertently, unintentionally, and/or undesirably discharge the
combustion flame 106. The power supply 102 is configured to provide
the ionizer 104 with one or more voltage signals that enable the
ionizer 104 to generate unipolar ions, i.e., ions of a single
polarity, according to one embodiment.
[0025] The power supply 102 includes a voltage supply 114, a
transformer 116, and an output dampener 118, according to one
embodiment. The voltage supply 114 selectively generates
square-wave pulses of half a square-wave period, one square-wave
period, or multiple square-wave periods, according to various
embodiments. In one embodiment, the voltage supply 114 is
implemented as a DC voltage supply in series with a switch that is
operative to selectively decouple the DC voltage supply from the
transformer 116 and/or from the output dampener 118, according to
various embodiments.
[0026] The transformer 116 can be coupled between the voltage
supply 114 and the ionizer 104 to convert a first voltage signal
having a first voltage level into a second voltage signal having a
second, higher, voltage level, according to one embodiment. The
transformer 116 may be a step-up transformer that converts a
voltage signal that is, for example, between 100-500 V into a
voltage signal that is, for example, between 4-10 kV, according to
one embodiment. The transformer 116 may include a primary winding
120 and a secondary winding 122. The primary winding 120 may have a
number of turns that is less than a number of turns of the
secondary winding 122. The primary winding 120 may be connected to
the voltage supply 114, and the secondary winding 122 may be
connected to the ionizer 104, according to one embodiment.
[0027] The output dampener 118 enables the power supply 102 to
provide a first polarity output voltage signal that exceeds or
surpasses a first polarity corona onset voltage while limiting,
suppressing, dampening, and/or preventing a second polarity output
voltage signal from exceeding or surpassing a second polarity
corona onset voltage, according to one embodiment. For example, the
output dampener 118 enables the power supply 102 to provide a first
polarity output voltage signal that is above a first polarity
corona onset voltage of 4 kV while prohibiting the power supply 102
from generating a second polarity output voltage signal that is
below or more negative than -4 kV. In other embodiments, the output
dampener 118 enables the power supply 102 to provide a first
polarity voltage signal that is below or more negative than -4 kV
while prohibiting the power supply 102 from generating a second
polarity voltage signal that is above or more positive than 4 kV.
Thus, the power supply 102 can be configured to generate a positive
high-power voltage that is equal to or greater than a positive
corona onset voltage, or the power supply 102 can be configured to
generate a negative high-power voltage that is equal to or more
negative than a negative corona onset voltage, according to various
embodiments.
[0028] The output dampener 118 can include one or more passive
electronic components configured to suppress or dampen power supply
output voltage surges or spikes of a particular polarity, according
to one embodiment. The output dampener 118 can be referenced by
several different terms, such as output voltage controller, output
voltage suppressor, output voltage filter, output filter, voltage
filter, output limiter, output voltage limiter, field regulator,
magnetic field regulator, magnetic field rate suppressor, or the
like. In one implementation, the output dampener 118 is a resistor
operatively or electrically coupled in parallel to the voltage
supply 114 and to the transformer 116. In another implementation,
the output dampener 118 is a resistor in series with a diode, with
the resistor and diode being coupled in parallel to the voltage
supply 114 and to the transformer 116. The output dampener 118 can
be operatively or electrically coupled to the primary winding 120
of the transformer 116 or can be optionally and alternatively
coupled to the secondary winding 122 of the transformer 116,
according to various embodiments.
[0029] In one embodiment, the operation of the output dampener 118
can be described in terms of magnetic flux .phi.. After the voltage
supply 114 applies a voltage to the primary winding 120, current
begins flowing through the primary winding 120. As the current
through the primary winding 120 increases with time, the magnetic
flux .phi. that permeates the primary winding 120 and the secondary
winding 122 also increases with time. The change in magnetic flux
.phi. with respect to time determines the magnitude of the voltage
generated across the secondary winding 122. Faraday's law describes
the magnitude of the voltage across the secondary winding 122 as
follows:
V=N*(d.phi./dt) (Equation 3),
where V is the voltage across the secondary winding 122,
[0030] N is the number of turns of the secondary winding 122,
and
[0031] D.phi./dt is the rate of change of the magnetic flux .phi.
through the secondary
winding 122 with respect to time.
[0032] Since the voltage across the secondary winding 122 is
proportional to the change in the magnetic flux .phi., the
increases in rate of the magnetic flux .phi. generate a positive
voltage and decreases in the rate of the magnetic flux .phi.
generate a negative voltage, across the secondary winding 122.
Furthermore, faster magnetic flux .phi. changes, i.e., higher rates
of change, generate higher voltages across the secondary winding
122. Therefore, the output dampener 118 can enable the power supply
102 to generate a positive voltage that exceeds a positive corona
onset voltage by not impeding increases in the magnetic flux .phi.,
and the output dampener 118 can limit, suppress, or dampen the
negative voltage generated by the power supply 102 by slowing the
rate by which the magnetic flux .phi. collapses or decreases when
the voltage supply 114 removes voltage from the primary winding
120, according to one embodiment. In another embodiment, the output
dampener 118 is configured to enable the power supply 102 to
generate a negative voltage that exceeds or is more negative than
the negative corona onset voltage while limiting, suppressing,
dampening, or preventing the power supply output voltage from
exceeding the positive corona onset voltage.
[0033] The rate by which the magnetic flux .phi. decreases is
proportional to the rate by which current through the primary
winding 120 decreases. The output dampener 118 can reduce the
maximum negative voltage across the secondary winding 122 by
reducing the rate of change of the magnetic flux .phi. by reducing
the rate of change of the current through the primary winding 120,
according to one embodiment. Without the output dampener 118, when
the power supply 102 removes voltage from across the primary
winding 120, e.g., by opening a switch, the power supply 102
removes a path for current in the primary winding 120 to continue
flowing. The current that was flowing through the primary winding
120 is abruptly changed from a first current level to a second
current level that is approximately 0 amps ("A"). The abrupt change
from the first current level to the second current level results in
a rapid decrease in the magnetic flux .phi. and therefore can
result in a large induced negative voltage across the secondary
winding 122.
[0034] The output dampener 118 provides a current path 124 to allow
current that was flowing through the primary winding 120 to at
least partially continue flowing. In one embodiment, the output
dampener 118 includes a resistor in series with a diode, and the
diode is oriented to allow current to flow in the direction of the
current path 124. The current that was flowing through the primary
winding 120 gradually decreases as it dissipates through the
resistance of the output dampener 118, but the initial rate of
change of the current through the primary winding 120 from a first
current level to a second current level can be significantly
reduced, as compared to when the power supply 102 does not include
the output dampener 118. As a result, the output dampener 118
enables the power supply 102 to excite the ionizer 104 to
selectively generate ions of a single polarity for charging the
combustion flame 106 to one or more voltage levels, according to
one embodiment.
[0035] While the discussion above is generally directed towards
embodiments where the output dampener 118 is connected in parallel
to the primary winding 120, it is to be understood that in other
implementations of the power supply 102, the output dampener 118
can perform the same function by being connected to the secondary
winding 122, instead of to the primary winding 120.
[0036] FIG. 2 illustrates graphs of the operation of the power
supply 102 (shown in FIG. 1) with and without the implementation of
the output dampener 118 (shown in FIG. 1), according to one
embodiment. A graph 202 illustrates an example of an output voltage
signal 203 that could be generated by the power supply 102, if the
power supply 102 does not include the output dampener 118. The
graph 202 includes an x-axis 204 that represents output voltage
levels with respect to a y-axis 206 that represents time. The graph
202 also includes an indication of a first corona onset voltage 208
and an indication of a second corona onset voltage 210. In one
embodiment, the first corona onset voltage 208 is a positive corona
onset voltage, and the second corona onset voltage 210 is a
negative corona onset voltage. In one embodiment, the first corona
onset voltage 208 is approximately 4 kV, and the second corona
onset voltage 210 is approximately -4 kV. The output voltage signal
203 includes a first section 212 and a second section 214. The
first section 212 is generated when the voltage supply 114 (shown
in FIG. 1) applies a first input voltage level to the transformer
116 (shown in FIG. 1). As shown, the first section 212 exceeds the
first corona onset voltage 208 to cause the ionizer 104 (shown in
FIG. 1) to generate positively charged ions. The second section 214
is generated when the voltage supply 114 removes the first input
voltage level from the transformer 116, or when the voltage supply
114 rapidly applies a second input voltage level to the transformer
116 that is lower than the first voltage level. The second section
214 exceeds the second corona onset voltage 210 and causes the
ionizer 104 to generate negatively charged ions, resulting in the
discharge of the combustion flame 106.
[0037] A graph 216 illustrates an example of an output voltage
signal 218 that could be generated by the power supply 102, if the
power supply 102 includes or implements the output dampener 118,
according to one embodiment. The graph 216 includes an x-axis 220
that represents output voltage levels with respect to a y-axis 222
that represents time. The graph 216 includes an indication of the
first corona onset voltage 208 and an indication of the second
corona onset voltage 210. The output voltage signal 218 includes a
first section 224 and a second section 226. The first section 224
is generated when the voltage supply 114 applies a first input
voltage level to the transformer 116. As shown, the first section
224 exceeds the first corona onset voltage 208 to cause the ionizer
104 to generate positively charged ions. The second section 226 is
generated when the voltage supply 114 applies a second input
voltage level to the transformer 116, e.g., when the voltage supply
114 removes the first input voltage level from the transformer 116.
As shown, by incorporating the output dampener 118 into the power
supply 102, the maximum negative amplitude 228 of the second
section 226 of the output voltage signal 218 can be limited,
suppressed, or dampened so that the second section 226 does not
exceed the second corona onset voltage 210. In other words,
implementation of the output dampener 118 prevents the power supply
102 from causing the ionizer 104 to generate negatively charged
ions, according to one implementation of the output dampener 118.
In other implementations, the output dampener 118 can be used to
enable the ionizer 104 to generate negatively charged ions while
preventing the ionizer 104 from generating positively charged
ions.
[0038] FIG. 3 illustrates an electrodynamic flame control system
300 for charging the combustion flame 106 to one or more voltage
levels, according to one embodiment. The electrodynamic flame
control system 300 represents one particular implementation of the
electrodynamic flame control system 100 of FIG. 1, according to one
embodiment. In the electrodynamic flame control system 300, the
output dampener 118 includes a resistor 302 electrically connected
or coupled to a diode 304 to enable current to flow from a first
node 306 to a second node 308. The resistor 302 and the diode 304
reduces the negative rate of current change through the primary
winding 120 when the voltage supply 114 removes voltage from the
primary winding 120. By reducing the negative rate of current
change through the primary winding 120, the output dampener 118
reduces the negative rate of magnetic flux .phi. change and
therefore reduces the peak value of the voltage that is induced
across the secondary winding 122 when the voltage supply 114
removes voltage from across the primary winding 120, according to
one embodiment. In other implementations of the output dampener
118, the orientation of the diode 304 can be changed to allow
current to flow from the second node 308 to the first node 306.
Such a reversal in orientation could be used to apply a negative
polarity voltage to the transformer 116 while limiting the peak
value of a positive voltage induced across the secondary winding
122 when the voltage supply 114 removes the negative polarity
voltage from across the primary winding 120, according to one
embodiment.
[0039] In one embodiment, the ionizer 104 of the electrodynamic
flame control system 100 can be implemented in the electrodynamic
flame control system 300 as a first electrode 310 and a second
electrode 312. The first electrode 310 can be electrically coupled
or connected to a first output terminal 314 and the second
electrode 312 can be electrically coupled or connected to a second
output terminal 316. The electrodes 310, 312 receive voltage,
energy, and/or power from the power supply 102, to supply ions to
the combustion flame 106 to charge the combustion flame 106 to one
or more voltage levels. In one embodiment, the first electrode 310
is a conductor such as a wire, a piece of metal, and/or a needle.
In one embodiment, second electrode 312 is a conductor that is
larger, e.g., has more surface area and/or more volume, than the
first electrode 310. In one embodiment, the first electrode 310 is
positioned proximate to and external to the combustion flame 106.
In one embodiment, proximate to and external to the combustion
flame 106 include being positioned at least 1 inch away from the
combustion flame 106. In one embodiment, the second electrode 312
is positioned proximate to and external to the combustion flame
106. In one embodiment, the first electrode 310 is positioned on
one side of the combustion flame 106 and the second electrode 312
is positioned on another side of the combustion flame 106. In
alternative implementations, the second electrode 312 is positioned
within the combustion flame 106. In one embodiment, the second
output terminal 316 of the power supply 102 is electrically coupled
or connected to the burner 108 so that the burner 108 functions as
the second electrode 312. In one embodiment, the second electrode
312 is omitted from the electrodynamic flame control system 300 and
the first electrode 310 is used to supply ions to the combustion
flame 106.
[0040] The power supply 102 may be configured to charge the
combustion flame 106 to a particular voltage that may be higher
than an output voltage of the power supply 102, according to one
embodiment. The combustion flame 106 includes the capacitance 112,
which may be charged by the receipt of ions from the electrodes
310, 312. As described previously in Equation 1 and Equation 2, the
voltage across the capacitance 112 can be expressed in terms of
charge, e.g., V=Q/C, or in terms of current, e.g., V=(l*t)/C. The
power supply 102 may be configured to provide an output voltage to
the ionizer 104 (shown in FIG. 1) or to the electrodes 310, 312
that is between 4-10 kV because 4 kV can be the corona onset
voltage and because 10 kV can be the breakdown voltage of the
surrounding or proximate fluid. Assuming, the capacitance 112 is
approximately 3 pF, the power supply 102 and the electrodes 310,
312 can charge the combustion flame 106 to 15 kV by supplying 45
nanocoulombs ("nC") to the capacitance 112. Described in another
way, the power supply 102 and electrodes 310, 312 can charge the
combustion flame 106 to 15 kV by supplying 45 nanoampere-seconds
("nA-s"), which can be supplied with an ion current of 4.5
milliamperes ("mA") for 10 microseconds (".mu.s"). Alternatively,
the power supply 102 and the electrodes 310, 312 can charge the
combustion flame 106 to 40 kV by supplying 120 nA-s with 12 mA for
10 .mu.s (i.e., 100 kHz pulse). Thus, by using the ionizer 104 or
the electrodes 310, 312, the power supply 102 can be configured to
charge the combustion flame 106 to a voltage that is higher than
the output voltage of the power supply 102, according to various
embodiments.
[0041] FIG. 4 illustrates an electrodynamic flame control system
400 for charging the combustion flame 106 to one or more voltage
levels, according to one embodiment. The electrodynamic flame
control system 400 includes a controller 402 that is
communicatively coupled or operatively coupled to control multiple
instances of the power supply 102 (inclusive of power supplies
102a, 102b, 102c, 102d), according to one embodiment. The
controller 402 can be configured to selectively operate the voltage
supplies 114 (shown in FIG. 1) of the power supplies 102 and the
corresponding ionizers 104 (inclusive of ionizer 104a, 104b, 104c,
104d). The controller 402 can be configured to customize the
quantity, duration, and polarity of ions supply to the combustion
flame 106. In one embodiment, the controller 402 causes the power
supplies 102a, 102b, 102c, 102d to sequentially provide ions of a
single polarity to the combustion flame 106 by time-multiplexing
the ion generation. In another embodiment, the controller 402
causes one or more of the power supplies 102a, 102b, 102c, 102d to
generate positive ions to selectively charge the combustion flame
106 while causing others of the power supplies 102a, 102b, 102c,
102d to selectively and sequentially generate negative ions to
selectively discharge the combustion flame 106. In one
implementation, the controller 402 time-multiplexes the operation
of the power supplies 102a, 102b, 102c, 102d by: causing the power
supply 102a to selectively charge the combustion flame 106; causing
the power supply 102b to selectively discharge the combustion flame
106; causing the power supply 102c to selectively charge the
combustion flame 106; and causing the power supply 102d to
selectively discharge the combustion flame 106. More or less power
supplies 102 and ionizers 104 can be implemented to customize the
quantities, polarity, and duration of ions supply to the combustion
flame 106, according to various embodiments.
[0042] FIG. 5 illustrates a method 500 for operating an
electrodynamic combustion system, according to one embodiment.
[0043] At block 502, the method generates, with a power supply, a
voltage signal having a first portion of a first polarity and
having a second portion of a second polarity, according to one
embodiment. The first portion of the voltage signal can be greater
than or equal to a first predetermined threshold.
[0044] At block 504, the method suppresses the second portion of
the voltage signal, with an output dampener, to prevent the second
portion of the voltage signal from exceeding a second predetermined
threshold, by reducing a rate of current change in a transformer of
the power supply, while generating the second portion of the
voltage signal, according to one embodiment.
[0045] At block 506, the method generates ions of the first
polarity, with an ionizer, in response to receiving the first
portion of the voltage signal, according to one embodiment.
Generating ions can include supplying the ions to a combustion
flame to charge the combustion flame to a voltage to alter one or
more characteristics of the combustion flame.
[0046] While various aspects and embodiments have been disclosed
herein, other aspects and embodiments are contemplated. The various
aspects and embodiments disclosed herein are for purposes of
illustration and are not intended to be limiting, with the true
scope and spirit being indicated by the following claims.
* * * * *