Patent Application
20250112011
The following description relates to controlling electrical contactors and, more particularly, to protecting hardware providing arc protection when opening contactors and especially during a short circuit event.
Contactor assemblies are used in electrical applications, such as aircraft power distribution systems, where power and current flow control of single or multi-phase power distribution system is required. A primary power distribution assembly typically has a panel on which several electrical contactors are mounted.
Each of the contactors is connected to an electrical bus bar and allows current to flow through the contactor and the corresponding bus bar whenever the contactor is in a closed position. The electrical power and current flow through the contactor is controlled by mechanically actuating a contact plate within the contactor such that, when current flow is desired to pass through the contactor, the contact plate is pushed into electrical contact with two leads and forms an electrical path coupling the leads and thereby allowing current to flow through it.
In aerospace electric power generation and distribution systems, electric power is provided from power sources such as generators, converters, Transformer Rectifier Units (TRUs), and batteries to load buses or between load buses via such contactors. In the event of a failure, contactors may be closed to provide power from an alternate power source or opened to prevent cascading failure effects.
These contactors may be controlled by control units such as generator control units or bus power control units. Determination for whether these contactors should be open or closed is performed in controller software or firmware based on a number of inputs such as generator voltage, bus voltage, TRU voltage, etc. pending the controller type.
In a short circuit event the controller determines that the contactors should be opened. In such a case, however, due to the short circuit, a high energy arc may be formed across the main contactors preventing isolation via the main contacts of a contactor. One approach to ensure the arc is not formed (or if it is that it is extinguished quickly) is to provided a fuse in-line with the contactor. The fuses can be traditional fuses or so-called “pyrofuses.” Both types of fuses are “one-time use” devices that need to be replaced after they have been blown or otherwise activated.
Disclosed is mechanical contactor isolation system. The system can be used in a short circuit or any time the contactor is to be opened.
In one embodiment, a high voltage DC contactor control system that includes a first contactor configured to be connected to a positive feeder line, the first contactor being controlled by a drive voltage and having a first portion and a second portion that when contacting allow current to flow between them. The system also includes a short circuit protection system operably connected to the drive voltage configured to reducing arcing between portions of the first contactor. The short circuit protection system includes: a first arc prevention element; and a first arc prevention driver arranged to cause the first arc prevention element to be disposed between the first and second portions of the first contactor to prevent arcing between them.
In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the system can further include: a sensor to sense a short circuit; and a contactor controller configured to control operation of the first contactor and the short circuit protection system.
In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, in the event of a short circuit, the contactor controller is configured to cause the first contactor to open in the event of a short circuit and to cause the short circuit protection supply system to move the first arc prevention element between the first and second portions.
In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, first arc prevention element can begin moving at the same time as or before the first contactor begins opening.
In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the first contactor can be configured to be to be opened by removing the drive voltage from it and that first arc prevention element can be configured to be moved when the drive voltage is applied to the first arc prevention driver.
In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, first arc prevention driver can be a coil.
In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the first arc prevention element can include a metallic portion and an insulating portion and the first arc prevention driver can be configured to electrically interact with the metallic portion to cause the insulation portion to move between the first and second portion of the contactor.
In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the insulating portion can be formed of a dielectric material.
In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the system can further include a second contactor connected to a negative feeder line, the second contactor being controlled by the drive voltage and having a first portion and a second portion that when contacting allow current to flow between them.
In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the short circuit protection system can further include a second arc prevention element and a second arc prevention driver configured to cause the second arc prevention element to be disposed between the first and second portions of the second contactor to prevent arcing between them.
Also disclosed is a method of controlling a DC contactor. The method can include: determining that short circuit exists on a positive feeder line; opening a first contactor connected to the positive feeder line, the first contactor being controlled by a drive voltage and having a first portion and a second portion that when contacting allow current to flow between them; and moving a first arc prevention element between the first and second portions of the first contactor to prevent arcing between them.
In addition to one or more of the features described above, or as an alternative to any of the foregoing method embodiments, the first arc prevention element can be controlled by a first arc prevention driver.
In addition to one or more of the features described above, or as an alternative to any of the foregoing method embodiments, a contactor controller can control operation of the first contactor and the first arc prevention driver based on the determination that the short circuit exists.
In addition to one or more of the features described above, or as an alternative to any of the foregoing method embodiments, the first contactor can be caused to be opened by removing the drive voltage from it and the first arc prevention element is caused to be moved when the drive voltage is applied to the first arc prevention driver.
In addition to one or more of the features described above, or as an alternative to any of the foregoing method embodiments, first arc prevention driver can be a coil.
In addition to one or more of the features described above, or as an alternative to any of the foregoing method embodiments, the first arc prevention element can include a metallic portion and an insulating portion and the first arc prevention driver electrically interacts with the metallic portion to cause the insulation portion to move between the first and second portion of the contactor.
In addition to one or more of the features described above, or as an alternative to any of the foregoing method embodiments, the insulating portion can be formed of a dielectric material.
Also disclosed is a high voltage DC contactor control system that includes a control element configured to be connected to a positive feeder line to control power through the positive feeder line. The control element can be a solid-state element (e.g., a transistor) in one embodiment. The system also includes: a short circuit protection system operably connected to a drive voltage configured to reducing arcing between portions of the first contactor. The short circuit protection system in this embodiment includes: a first contactor configured to be connected to a positive feeder line, wherein first contactor can be configured to be controlled by a drive voltage and have a first portion and a second portion that when contacting allow current to flow between them; a first arc prevention element; and a first arc prevention driver configured to cause the first arc prevention element to be disposed between the first and second portions of the first contactor to prevent arcing between them.
In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the system can further include a sensor to sense a short circuit and a controller configured to control operation of the control element and the short circuit protection system.
In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the controller be configured to cause the control element to become non-conductive in the event of a short circuit and that causes the short circuit protection supply system to move the first arc prevention element between the first and second portions in the event of a short circuit.
In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the first arc prevention element can begin moving as or before the first contactor begins opening.
The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike:
While the invention is further discussed below, it has been discovered that while the current fail-safes utilized in the industry may be effective, certain improvements can be made. In particular, arcing can be reduced or eliminated in all situations and in short circuit situation in particular by inserting insulated arc prevention elements either in a mechanical contactor or in a contactor that is part of.
The disclosed system can be reusable and such, the insulated arc prevention elements do not need to be replaced due to normal operation of when a short is detected.
With reference to
The power is sent to a panel box 24 that contains multiple electrical buses and contactor assemblies for controlling how the power is distributed throughout the aircraft 10. Through the use of the contactor assemblies, power may be controlled for each onboard electrical load.
An exemplary panel box 24 includes multiple bus bars that can be connected to various aircraft systems by contactor assemblies (or simply contactors). Not by way of limitation but for example only,
The contactor assembly 100 further includes a contactor actuator 111 that can be, for example, a solenoid that includes a plunger 112 with an insulator 113 at a distal end thereof and a movable bus bar 114. At a central portion thereof, the movable bus bar 114 is coupled to the plunger 112 via the insulator 113. At opposite ends thereof, the movable bus bar 114 includes contact pads 1141 and 1142. The movable bus bar 114 is movable by the contactor actuator 111 into a first position and a second position.
At the first position, the contact pads 1141 of the movable bus bar 114 contact the stationary contact pads 1061 and 1062 such that the corresponding individual internal bus bars 106 are electrically coupled with one another. At the second position, the contact pads 1141, 1142 are displaced from the stationary contact pads 1061 and 1062 such that the corresponding internal bus bars 106 are decoupled from one another.
Thus, in operation, the electrical contactor 102 is operable in a first mode or in a second mode. In the first mode, corresponding internal bus bars 106 are electrically-coupled with each other in the interior 108 of the housing 104. In the second mode, the corresponding internal bus bars 106 are electrically decoupled from one another in the interior 108 of the housing 104.
In
The operating logic 152 can be any hardware of software (or combination thereof) that is used to determine whether a particular contactor should be opened of closed. Determination of whether a particular contactor should be open or closed is performed in controller software or firmware in the logic 152 and can be based on a number of inputs such as generator voltage, bus voltage, TRU voltage depending on the controller type. In the below explanation, the operating logic can receive signal from a sensor that indicates that a short circuit has occurred. The signal can be directly from a sensor 180 (e.g, a current sensor) or from another sensor or controller etc. In the event a short circuit occurs, the contactor actuator 111 moves the bus bar 114 into the second (open) position. Further, it shall be understood that the contactor control circuitry 150 can provide contactor enable signals to additional contactor systems 100. These signals can be provided to a mechanical contactor or can be provided to a solid-state contactor/control element.
As shown more fully below, in addition, the contactor control circuitry 150 will also cause current through the bus bars 106 to cease by mechanically inserting insulated arc prevention elements in the current path. This can prevent arcing between, for example, elements 1061/1141 and 1062/1142 when the contactor 102 opens.
While a mechanical contactor is shown above, the teachings herein can be implemented in the case of a solid-state control element. This is shown, for example, in
With reference now to
As shown, each system includes two contactors/control elements, one of the main positive line (V+) and one for the main negative line (V−). These are high voltage DC lines (feeders) in one embodiment. As such, the voltage on V+ and V− can be +/−135+/−270 Vdc, +/−400 Vdc or even higher. Indeed, these lines can carry high current in high voltage networks in some cases. The teachings herein apply to all situations but more particularly to high voltage
In
In
Both
In any embodiment herein, the contactor control circuitry 150 of
As shown in
Regardless of the form, upon receiving a signal (e.g., a voltage/current) the arc prevention driver 334 will cause one or more insulated arc prevention elements 332a, 332b to be inserted into the incoming or outgoing power flow so that the power does not pass through the contactors 102 as they are opened in a short circuit situation. Of course, the insulated arc prevention elements 332a, 332b may be used in other cases (e.g., high current that is not the result of a short) as well.
As shown, the metallic shaft 502 is adjacent or otherwise in electrical contact (e.g, surround) by the arc prevention driver 334. Application of a voltage across the arc prevention driver 334 will cause an interaction with the shaft 502 that causes the insulated arc prevention element 332 to move. As shown below, this can cause the insulated portion 504 to be disposed between portions of the contactors as they are being opened to reduce arc time or prevent it completely.
The contactors 102a, 102b each include a first and second portions that can move relative to one another. As shown, the first or positive contactor 102a includes a first portion 102a (1) and a second portion 102a(2). Similarly, the second or negative contactor 102b includes a first portion 102b(1) and a second portion 102b(2). The first portion and second portion of each contactor 102 can be arranged (e.g., spring loaded) such that when they not receiving a driving current/voltage, the portions are separated and do not pass power/current. This is shown in
As shown in
As shown in
The application of the voltage to the first and second arc prevention driver 334a, 334b can occur when the contactor control circuitry 150 receives an indication (e.g., sensor signal) that a short has occurred as illustrated in
In another embodiment, the systems shown in
In more detail,
The contactors 102a, 102b each include a first and second portions that can move relative to one another. As shown, the first or positive contactor 102a includes a first portion 102a(1) and a second portion 102a(2). Similarly, the second or negative contactor 102b includes a first portion 102b(1) and a second portion 102b(2).
In the event that a short circuit is detected, the gate drive signal can be set to the appropriate level so that the control elements 402a, 402b become non-conductive.
In a manner similar to the above, upon application of voltage (e.g., 28V) to first and second arc prevention drivers 434a, 434b, the insulated arc prevention elements 432a, 432b move to the right so they are disposed between the portions of the contactors 102 such that the dielectric portion of the insulated arc prevention elements 432a, 432b is between the portions and thereby prevents or stops arcing between them.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, element components, and/or groups thereof.
While the present disclosure has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the present disclosure. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the present disclosure without departing from the essential scope thereof. Therefore, it is intended that the present disclosure not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this present disclosure, but that the present disclosure will include all embodiments falling within the scope of the claims.
