U.S. patent application number 15/341321 was filed with the patent office on 2017-04-13 for virtual electronic circuit breaker.
This patent application is currently assigned to Astronics Advanced Electronic Systems Corp.. The applicant listed for this patent is Astronics Advanced Electronic Systems Corp.. Invention is credited to Massoud Vaziri.
Application Number | 20170104326 15/341321 |
Document ID | / |
Family ID | 58500097 |
Filed Date | 2017-04-13 |
United States Patent
Application |
20170104326 |
Kind Code |
A1 |
Vaziri; Massoud |
April 13, 2017 |
Virtual Electronic Circuit Breaker
Abstract
A virtual electronic circuit breaker having an electrical relay
and a control circuit, the control circuit including a load and
wire protection ("OC") detection unit, a microprocessor and a
driver. The OC detection unit is configured to monitor a power flow
and the electrical relay is effective to control it. The driver is
effective to cause the relay to stop the power flow upon receipt of
a deactivation command. The OC detection unit is effective to cause
the driver to receive a deactivation command if the OC detection
unit senses that a short circuit condition or an overload condition
exists. The microprocessor of the control unit is configured so as
to be capable of, at least, receiving input from the OC detection
unit and sending output to the driver.
Inventors: |
Vaziri; Massoud; (Redmond,
WA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Astronics Advanced Electronic Systems Corp. |
Kirkland |
WA |
US |
|
|
Assignee: |
Astronics Advanced Electronic
Systems Corp.
Kirkland
WA
|
Family ID: |
58500097 |
Appl. No.: |
15/341321 |
Filed: |
November 2, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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14044303 |
Oct 2, 2013 |
|
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15341321 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H02H 3/165 20130101;
H02H 3/105 20130101; H02H 1/06 20130101; H02H 3/083 20130101 |
International
Class: |
H02H 3/16 20060101
H02H003/16; H02H 3/00 20060101 H02H003/00; H02H 1/00 20060101
H02H001/00 |
Claims
1. A virtual electronic circuit breaker, comprising: an electrical
relay effective to control an amount of power flow; a solid state
switch in parallel with the electrical relay; a control circuit,
having a single Load and Wire Protection ("OC") detection unit, a
microprocessor and a driver; said driver effective to cause said
relay to stop said power flow upon receipt by the driver of a
deactivation command; said single OC detection unit configured to
both monitor said power flow and effective to cause said driver to
receive a deactivation command in response to a detection, by said
single OC detection unit, that an overload condition exists; and
said microprocessor configured to be capable of receiving input
from said single OC detection unit, sending output to said driver,
and configured to be capable of receiving a "reset" command, a
"collar" command, an "on" command, and an "off" command from a
control panel.
2. The virtual electronic circuit breaker of claim 1 wherein said
power flow is selected from the group consisting of 1-phase
alternating current (AC), 3-phase AC and direct current (DC).
3. The virtual electronic circuit breaker of claim 2 wherein said
power flow is 1-phase AC and said virtual electronic circuit
breaker is located on an aircraft.
4. The virtual electronic circuit breaker of claim 1 wherein said
microprocessor is effective to send to outside said control circuit
an amount of indication and status information.
5. The virtual electronic circuit breaker of claim 4 wherein said
microprocessor is effective to send said information to an aircraft
cockpit.
6. The virtual electronic circuit breaker of claim 1 further
comprising a silicon-controlled rectifier (SCR) in parallel with
the relay, wherein a voltage across the relay causes the SCR to
trigger.
7. The virtual electronic circuit breaker of claim 1 wherein said
virtual electronic circuit breaker is located on an aircraft.
8. The virtual electronic circuit breaker of claim 7 wherein said
microprocessor is effective to cause said driver to receive a
deactivation command upon receipt by the microprocessor of an "off"
command.
9. The virtual electronic circuit breaker of claim 1 wherein said
microprocessor is effective to communicate with a programming and
test bus.
10. The virtual electronic circuit breaker of claim 1, further
comprising a redundant source of power effective to allow said
control circuit and said relay to operate while only receiving
power from said redundant source of power.
11. The virtual electronic circuit breaker of claim 1 further
comprising a ground fault interruption (GFI) detection unit.
12. The virtual electronic circuit breaker of claim 11 wherein said
GFI detection unit is effective to, when the GFI detection unit
senses that a ground fault condition has occurred, communicate to
said microprocessor that a ground fault condition has occurred.
13. The virtual electronic circuit breaker of claim 12 wherein said
GFI detection unit is integrated with said control circuit.
14. An electrical system for an aircraft, comprising a source of
limited power; a load, drawing an amount of power flow from said
source of limited power; an electrical relay effective to control
said amount of power flow; a solid state switch in parallel with
the electrical relay; a control circuit, having a single Load and
Wire Protection ("OC") detection unit, a microprocessor and a
driver; said driver effective to cause said relay to stop said
power flow upon receipt by the driver of a deactivation command;
said single OC detection unit configured to both monitor said power
flow and effective to cause said driver to receive a deactivation
command in response to a detection, by said single OC detection
unit, that an overload condition exists; and said microprocessor
configured to be capable of receiving input from said single OC
detection unit, sending output to said driver, and configured to be
capable of receiving a "reset" command, a "collar" command, an "on"
command, and an "off" command from a control panel.
15. The electrical system of claim 14, wherein said source of
limited power is an aircraft engine.
16. The electrical system of claim 15, wherein said load is the
actuator mechanism of an aircraft control surface.
17. A method of protecting an electronic circuit with a virtual
electronic circuit breaker, comprising the steps of: providing a
power flow; providing an electrical relay effective to control said
amount of power flow; providing a solid switch in parallel with the
electrical relay; providing a control circuit, having a single Load
and Wire Protection ("OC") detection unit, a microprocessor and a
driver, wherein said driver is effective to cause said relay to
stop said power flow upon receipt by the driver of a deactivation
command, and wherein said microprocessor is configured to be
capable of receiving input from said single OC detection unit,
sending output to said driver, and configured to be capable of
receiving a "reset" command, a "collar" command, an "on" command,
and an "off" command from a control panel; monitoring said power
flow utilizing said single OC detection unit; and causing said
driver to receive a deactivation command when an overload condition
is sensed.
18. The method of claim 17 wherein said power flow is 1-phase AC
and said virtual electronic circuit breaker is located on an
aircraft.
19. The method of claim 17 wherein said microprocessor is effective
to receive commands from and send information to outside said
control circuit.
20. The method of claim 17 wherein said microprocessor is effective
to cause said driver to receive a deactivation command upon receipt
by the microprocessor of an "off" command
Description
FIELD OF THE DISCLOSURE
[0001] The subject matter of the present disclosure generally
relates to circuit control devices, and more particularly relates
to virtual circuit breakers utilizing microprocessors.
BACKGROUND OF THE DISCLOSURE
[0002] Control devices for circuits are important in many
electrical applications. For instance, various circuit breaker
designs that are useful in numerous applications have been
previously developed and disclosed.
[0003] In current aerospace power distribution systems, electrical
loads are fed through a thermal circuit breaker and a power relay
connected in-series, in order to provide load and wire protection
(over-current or "OC") and load On/Off control (switching).
Alternatively, a Solid State Power Controller (SSPC) may be used to
perform these same functions.
[0004] The thermal circuit breaker/power relay solution has a long
service history, but this combination can be bulky and labor
intensive for installation and trouble shooting. The SSPC solution
has also been successfully implemented and operated with favorable
service history. However, SSPCs are not cost and/or volume
effective for higher power loads, largely due to the fact such
applications require a high number of metal-oxide-semiconductor
field-effect transistors (MOSFETs).
[0005] By example, U.S. Pat. No. 6,470,224 to Drake et al.
discloses an aircraft power system including a SSPC disposed within
a secondary power distribution assembly. Another example is U.S.
Patent Application Publication No. 2013/0100567 to Reynolds et al.,
which discloses a system for protecting electrical power
distribution circuits. Yet another example is U.S. Patent
Application Publication No. 2013/0050880 to Rozman et al., which
discloses a solid state power controller system. The disclosures of
U.S. Pat. No. 6,470,224 and Patent Application Publication Nos.
2013/0100567 and 2013/0050880 are incorporated by reference herein
in their entirety.
[0006] The subject matter of the present disclosure is directed to
overcoming, or at least reducing the effects of, one or more of the
problems set forth above.
BRIEF SUMMARY OF THE DISCLOSURE
[0007] Disclosed is a virtual electronic circuit breaker (VECB)
having an electrical relay and a control circuit. The electrical
relay is effective to control the power flow of a power line. The
control circuit has a load and wire protection ("OC") detection
unit, a microprocessor and a driver. When an overload or short
circuit condition is detected, the driver receives a command that
the relay should stop the flow of power in the power line and, in
return, the relay is caused to shut off power flow in the line,
thus preventing or mitigating potential damage and/or harm.
[0008] There exists many different embodiments of the disclosed
system, including many that have additional functionality to that
discussed above. For instance, a redundant power supply can allow
the relay and control circuit to operate without another source of
power. A ground fault interrupt (GFI) detection unit can sense, and
begin the response to, a ground fault condition. The microprocessor
of the control circuit can actively control the circuit's
operation, and in some embodiments, receive and communicate
information with other components outside the disclosed system.
[0009] The disclosed subject matter presents several advantages
over previously available systems and methods.
[0010] One advantage of the disclosed subject matter is that it can
be utilized with 1-phase Alternating Current (AC), 3-phase AC or
Direct Current (DC) power with minor circuit changes.
[0011] Another advantage is that utilization of the disclosed
subject matter may decrease overall project costs, depending in
part on the load rating of any particular implementation.
[0012] Yet another advantage of the disclosed subject matter is
that it allows for the utilization of conventional, proven
components such as off the shelf (OTS) power relays and control
circuits. This may, in turn, result in schedule and project cost
reductions.
[0013] Yet another advantage of the disclosed subject matter is
that an over-current rating change only requires a software
set-point change, given that the power relay should be compatible
for the highest programmable VECB rating.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The foregoing summary, preferred embodiments, and other
aspects of the subject matter of the present disclosure will be
best understood with reference to a detailed description of
specific embodiments, which follows, when read in conjunction with
the accompanying drawings, in which:
[0015] FIG. 1 is a schematic diagram of an embodiment, having a
power bus, relay, load and control circuit.
[0016] FIG. 2 is a schematic diagram of the embodiment of FIG. 1,
having additional features such as a redundant board power supply
and GFI detection function.
[0017] FIG. 3 is a schematic diagram of an embodiment having two
relays, each connected to a dedicated driver.
[0018] FIG. 4 is a diagram of degradation testing.
[0019] FIG. 5 is a diagram of waveforms during relay opening.
[0020] FIG. 6 is a diagram of waveforms during the contactor
commutation period.
[0021] FIG. 7 illustrates a circuit board for use during lifecycle
testing.
[0022] FIG. 8 is a schematic diagram of another embodiment, with
the solid state switch in parallel with the relay.
[0023] Like reference numbers and designations in the various
drawings indicate like elements. Arrows in the schematic drawings
should be understood to represent logic pathways that are generally
indicative of the flow direction of information or logic, and that
such arrows do not necessarily represent traditional electrical
pathways.
DETAILED DESCRIPTION OF THE DISCLOSURE
[0024] FIG. 1 is a schematic diagram of one embodiment of the VECB.
A power bus 101, which may be a source of limited power, such as a
generator on an aircraft, supplies an amount of power flow along
power line 102, which is in this embodiment carrying 3-phase AC
power. It should be understood that the disclosed subject matter
can be utilized with 1-phase AC and 3-phase AC power, as well as
other power configurations, including without limitation 28VDC and
270VDC. Electrical relay 103 is effective to control this power
flow. For example, relay 103 can allow power to flow from power bus
101 to load 104 or, inversely, prevent such flow. Various
electrical relays are suitable for use with the disclosed subject
matter, including by way of example commercially available OTS
units. Control circuit 105 includes OC detection unit 106,
microprocessor 107 and driver 108. Upon receipt of a deactivation
command, driver 108 is effective to cause relay 103 to stop the
flow of power in power line 102. OC detection unit 106 is
configured to monitor the power flow in power line 102 with, for
example, a current sensor(s). OC detection unit 106 is capable of
detecting whether a short circuit or overload condition exists. If
one of these conditions is sensed, OC detection unit 106 causes
driver 108 to receive a deactivation command, which, in turn, would
cause the power flow in power line 102 to be shut off, thereby
preventing or limiting the damage or harm that might otherwise be
caused by an overload or short circuit condition. Microprocessor
107 is configured to, at a minimum, be capable of receiving input
from OC detection unit 106 and sending output to driver 108. It is
understood that microprocessor 107 may perform any number of
additional functions, and may be programmable to operate and
control the control circuit 105 in a variety of fashions.
[0025] FIG. 2 is a schematic diagram of the embodiment of FIG. 1
having additional features and functionality. Redundant Board Power
Supply 109 is connected to control circuit 105 and relay 103 and is
effective to allow control circuit 105 and relay 103 to operate
even when redundant board power supply is the only power source for
these units. Such a redundant power supply increases overall system
integrity and can help guard against unexpected power loss from
other sources. This can be particularly important in applications,
such as aircraft, where it is critical that system functionality be
maintained even in the event of a loss of primary power.
[0026] In the embodiment of FIG. 2, microprocessor 107 is capable
of sending and receiving various information outside of the control
circuit. Such functionality may be useful in applications where
control of the embodiment system by an outside entity, for instance
a flight officer of an aircraft, is advantageous or required. In
the embodiment, indication and status information is sent outside
of the embodiment system. This information, by way of example, may
be recorded, viewed, analyzed or otherwise manipulated. For
example, a visual control panel in the cockpit of an aircraft could
indicate to a flight officer that the embodiment system is
operating effectively. It is understood that there are many human
interface schemes, for example, flight deck multi-function displays
(MFDs), capable of being utilized with the disclosed subject matter
and which will be apparent to those of skill in the art to which
the present disclosure pertains.
[0027] In the embodiment of FIG. 2, microprocessor 107 is effective
to receive "reset," "collar," "on," and "off" commands from outside
of the embodiment system. This allows the embodiment system, and
thus the power flow in power line 102, to be controlled remotely,
either automatically or by a human operator. For instance, upon
receipt of an "off" command by the microprocessor, the
microprocessor may cause driver 108 to receive a deactivation
command and thereby cause relay 103 to shut off power flow in power
line 102.
[0028] In the embodiment of FIG. 2, microprocessor 107 is effective
to communicate with a programming and test bus. This allows for the
embodiment virtual circuit electronic breaker to be tested to
ensure correct operation, and in certain embodiments, for the
circuit to be programmed with various settings and/or for various
tasks. For example, the threshold for determining that an overload
condition existed in the circuit could be raised, to for example,
account for load equipment with higher current demand that require
larger wire gage that are designed for higher overloads in power
line 102. It should be understood that microprocessor 107 may
receive input from various input devices, such as control panels,
keyboards, etc.
[0029] The embodiment depicted by FIG. 2 includes GFI detection
unit 110. In the particular embodiment, the GFI detection unit 110
is integrated with control circuit 105, but could optionally be not
integrated. GFI detection unit 110 is effective to, when it senses
that a ground fault condition has occurred, communicate to the
microprocessor that such a condition has occurred. This allows the
embodiment system to detect and react to ground fault conditions.
In an embodiment, an arc fault detection and protection algorithm
can be programmed into the microprocessor. In another embodiment,
GFI protection can be added by including an additional current
sensor (i.e., current transformer or hall effect sensor).
[0030] FIG. 3 is a schematic depiction of an embodiment in which a
single control circuit 301 operates to control the power flow in
both first power line 302 and second power line 303. In the
embodiment, first relay 304 is effective to control the flow of
power in first power line 302. Similarly, second relay 305 is
effective to control the flow of power in second power line 303.
First driver 306 is effective to cause first relay 304 to stop the
flow of power in first power line 302 upon receipt by first driver
306 of a deactivation command. Similarly, second driver 307 is
effective to cause second relay 305 to stop the flow of power in
second power line 303 upon receipt by second driver 307 of a
deactivation command. OC detection unit 308 monitors both first
power line 302 and second power line 303 and is effective to cause
first driver 306 or second driver 307 to receive a deactivation
command if a current overflow or short circuit condition is
detected in first power line 302 or second power line 303,
respectively. As illustrated by the embodiment depicted by FIG. 3,
components utilized in practicing the disclosed subject matter need
not have one-to-one relationships with one another or exist only in
single units.
[0031] In one embodiment, relay 103 is connected in parallel with a
solid state switch (SSSW). The SSSW is configured to close before
the relay 103 activates. Thus, before the relay 103 opens or
closes, the SSSW closes, which in turn prevents arc formation on
the relay contacts. Without the SSSW connected in parallel with the
relay 103 and being configured to close before the relay activates,
the relay 103 would otherwise need to be upsized significantly to
prevent arc formation. However, the use of a relay in parallel with
the SSSW prevents arc formation that would otherwise results from
the high voltage.
[0032] The invention utilizes the Tyco/Axicom V23079 relay
(manufactured by TE Connectivity Ltd. of Schauffhausen,
Switzerland), which is a standard telecom relay with a switching
current of 5 Amps and two changeover contacts formed from silver
nickel and gold-covered. The V23079 relay is rate for a 2 Amp
continuous current. Product literature accompanying the relay
recommends to never parallel relay contacts to double the contact
rating.
[0033] In this embodiment, the relay 103 includes two sets of
contacts. Each set of relay contacts is initially rated for 2 Amps
maximum continuous current. However, using the aforementioned
inventive feature of connecting the relay in parallel with the
SSSW, total continuous current is able to run at up to 4 Amps per
contact (8 Amps per contact set). Thus, use of the parallel
formation of SSSW with relay 103 allows for a contactor to be
utilized at twice the specification rating, which allows for a
reduction of the relay size otherwise required. It should be noted
that the invention additionally contemplates current flow of 5 Amps
per contact, up to 10 Amps per set.
[0034] The invention performed testing to increase the maximum
current to exceed double the rated current by paralleling relay
contacts with a SSSW. Relay degradation was determined by analyzing
contact resistance, with a measurement taken before each testing
series, and then again at points during testing. Utilizing the
inventive device, contact resistance did not change during testing,
indicating minimal relay degradation. The testing results are in
FIG. 4.
[0035] The testing included capturing waveforms to provide details
about the contactor commutation process. The waveforms are
illustrated in FIGS. 5-6. FIG. 5 illustrates waveforms of a
zoomed-in period of the relay opening, and the transition of
current from the relay to the silicon-controlled rectifier (SCR).
FIG. 6 illustrates a wider view of the entire commutation
period.
[0036] As shown in FIG. 5, CH1 is the line during the commutation
process. CH2 is the SCR current, and CHM is the relay current. CH3
is the voltage across the relay at 20V/div. FIG. 5 illustrates that
the transition of current from relay to SCR occurs quickly, in 1-2
microseconds, and that voltage across the relay never rise to a
potential voltage for arcs to occur.
[0037] FIG. 6 illustrates CH4 as the control input to open the
contactor. The contactor does not open until the relay starts to
open (i.e., after a delay). As shown, the current quickly transfers
from the relay (CHM) to the SCR (CH2), and then terminates within
another two microseconds on a current zero crossing.
[0038] The inventive device can therefore provide a reliable
contactor that can sustain in excess of 1,500,000 cycles of contact
cycles using a small, inexpensive relay.
[0039] FIG. 7 illustrates an exemplary circuit board lifecycle test
board, showing a bus contactor and load connections, used to test
the relay.
[0040] The inventive relay 103 in accordance with this embodiment
allows for switching of AC currents up to 15 Amps on a 115VAC, 400
Hz power bus. Control circuit 105 enables or closes an
opto-isolator, and then opens relay 103. The circuit 105 controls
the relay opening asynchronously with the AC bus waveform, allowing
the relay to open under minimal load stress due to the
opto-isolator having zero-cross detection features. Contactors do
not open until the relay begins to open (usually a delay of about 2
microseconds).
[0041] Once the relay 103 begins to open, voltage across the relay
causes a SCR in parallel with the relay 103 to trigger. This causes
current going through the relay to transfer to the SCR, causing the
relay 103 to then complete its opening with no arc formation. The
SCR then opens at the next current zero. It should be noted that
transition of current from relay 103 to SCR occurs very quickly,
such as 1-2 microseconds or a similar timeframe, thereby not
allowing the voltage across the relay to rise to an arc potential.
This avoids any damage to the contactors.
[0042] FIG. 8 illustrates an exemplary embodiment, with the circuit
breaker including a solid-state switch in parallel with the relay.
The inventive device in this embodiment offers the same
functionality as a MOSFET-based electronic circuit breaker. In
accordance with the invention, the device can be configured for
1-phase, 2-phase or 3-phase operations. Moreover, the device
utilizes inexpensive, commercial relays, significantly lowering the
cost per channel as compared to full solid-state electronic circuit
breakers.
[0043] As illustrated, a solid state switch is in parallel with the
relay, which prevents arc formation during opening and closing of
the relay. The prevention of arc formation increases longevity of
the relay, with an expected lifespan of 100 million cycles at its
intended current level.
[0044] The device allows for the channel rating to be scaled up by
utilizing multiple relays in parallel, as well as a higher current
solid state switch, while still remaining cost competitive. Thus, a
35 Amp virtual electronic circuit breaker remains cost-effective,
with the equivalent function of a thermal circuit and a relay in
series, whereas a 35 Amp solid state electronic circuit breaker is
cost-prohibitive. Further, the channel I2t rating can be changed
utilizing either simple discrete components, or a microprocessor
set point.
[0045] Shown in Appendix B is a Test Log of the contactor lifecycle
test.
[0046] It should be understood that various components of the
disclosed subject matter may communicate with one another in
various manners. For instance, components may communicate with one
another via a wire or, alternatively, wirelessly and by electrical
signals or via digital information. It is noted that PWB may be
utilized in the construction of many embodiments.
[0047] Although the disclosed subject matter has been described and
illustrated with respect to embodiments thereof, it should be
understood by those skilled in the art that features of the
disclosed embodiments can be combined, rearranged, etc., to produce
additional embodiments within the scope of the invention, and that
various other changes, omissions, and additions may be made therein
and thereto, without parting from the spirit and scope of the
present invention.
* * * * *