Interconnects for electrical power distribution systems

A contactor interconnect includes a lead post, a bus bar post and a plurality of electrically conductive heat rejection components. The lead post electrically connects to the bus bar post in series through the plurality of heat rejection components. The heat rejection components in turn connect electrically in parallel with one another between the lead post and the bus bar post for conducting current between the posts and passively dissipating heat conveyed from the lead post toward the bus bar post.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present disclosure relates to power distribution systems, and more particularly to interconnects for coupling contactors and bus bars.

2. Description of Related Art

Aircraft generally include onboard power systems with power generation devices connected to power distribution systems. The power generation system generates electrical power and the power distribution system routes the power from the power generation device to one or more power consuming devices or subsystems for powering onboard electronic systems. Such power generation systems typically include electrical contactors that control power flow through the power distribution systems. The contactors in turn control the flow of current between electrically opposed bus bars, typically through a movable element or relay device.

Contactors can generate heat due to current flow through the conductive elements of the contactor and the power distribution system. Generally, heat is conducted out the contactor leads extending through the contactor housing, into power distribution bus bars connected to the leads, and from the bus bars into the ambient atmosphere. In some power distribution systems, heat dissipation requirements can require sizing the bus bars beyond the size otherwise necessary for conducting electrical current. It can also require forming the bus bars from a heavier material than otherwise necessary, like copper or copper alloy, instead of aluminum or similar material.

Such conventional methods and systems have generally been considered satisfactory for their intended purpose. However, there is still a need in the art for improved contactors and contactor connection devices. The present disclosure provides a solution for this need.

SUMMARY OF THE INVENTION

A contactor interconnect includes a lead post, a bus bar post and a plurality of electrically conductive heat rejection components. The plurality of heat rejection components electrically connects the lead post to the bus bar post. The plurality of heat rejection components are arranged electrically in parallel with one another between the lead post and the bus bar post for conducting current between the posts and passively dissipating heat conveyed from the lead post toward the bus bar post.

In certain embodiments each heat rejection component can include upper and lower heat rejection surfaces that extend between the lead post and bus bar post. Opposed lower and upper heat rejection surfaces adjacent ones of the heat rejection components can define respective coolant flow passages extending therebetween for removing heat from the heat rejection component. Heat can be removed using an active and/or passive coolant flow. Heat can be rejected in a flow direction that is angled with respect current flow through the interconnect, such as at a 90 degree or any other suitable angle.

In accordance with certain embodiments, at least one of the heat rejection components can include a first and a second layer extending between the lead post and the bus bar post, wherein the first layer is integral with the second layer. The first layer can be ultrasonically welded to the second layer. At least one of the first and second layers can extend into at least one of the lead and bus bar posts.

It is contemplated that a third layer can be formed from a material that is different from the materials forming either or both the first and second layers. The third layer can be integral with the heat rejection component first and second layers. The third layer can form a portion of the at least one of the lead post and bus bar post. The third layer can also define a portion of a separation distance between opposed lower and upper heat rejection surfaces of adjacent heat rejection components. The third layer can connect the first and second layers of the heat rejection component with a bus bar for an aircraft power distribution system. The third layer can be ultrasonically welded to the first layer, to the second layer, to the contactor lead, or to the bus bar so as to be integral therewith.

A power distribution system includes a contactor with a lead and an interconnect as described above. The lead can be a first phase lead, the interconnect can be a first phase interconnect, the bus bar post can be a first phase bus bar post, and the power distribution can further include a second phase interconnect coupling a second phase contactor lead to a second phase bus bar lead.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made to the drawings wherein like reference numerals identify similar structural features or aspects of the subject disclosure. For purposes of explanation and illustration, and not limitation, a partial view of an exemplary embodiment of an aircraft electrical system including power distribution system in accordance with the disclosure is shown inFIG. 1and is designated generally by reference character20. Other embodiments of interconnects in accordance with the disclosure, or aspects thereof, are provided inFIGS. 2-5, as will be described. The systems and methods described herein can be used in electric power distribution systems, such as aircraft primary power distribution systems for example.

With reference toFIG. 1, aircraft10is shown including a power distribution system20with a power distribution panel100and an interconnect110, a power bus22, power consuming devices24, and a power source26. Power bus22connects power-consuming devices24with power source26through power distribution panel100and interconnect110. In certain embodiments power bus22is a component of an aircraft primary power system. Power-consuming devices24include, for purpose illustration and not for purposes of limitation, aircraft components such as control electronics, motor controllers, electric motors, and de-icing systems. Power source26is a generator coupled to a prime mover28, such as an aircraft main engine or auxiliary engine, and receives mechanical rotation therefrom for purpose generating a supply of multiphase current. It is to be understood that, in embodiments, power distribution system is a dual phase or a single-phase, i.e. direct current, power distribution system.

With reference toFIG. 2, an internal portion power distribution panel100is shown. Power distribution panel100includes a contactor102connected between generator-side bus bars104and power-consuming device bus bars106by an interconnect110. Contactor102and interconnect110are mounted to power distribution panel100by an epoxy plate121. Epoxy plate121can be formed from a material similar to that of the underlying printed wire board, such as a glass and epoxy laminate material, and is configured and adapted for controlling current through the power distribution system20by switching an internal mechanical relay, transistors, or a combination thereof (not shown inFIG. 2for clarity purposes) between on and off-states. When in the off-state, substantially no current flows from generator-side bus bar104to power-consuming device bus bar106. When in the on-state, current flows from generator-side bus bar104to power-consuming device bus bar106through interconnect110.

Current flow through contactor102generally results in the generation of heat due to resistive heating the internal relay or transistors within contactor102. In conventional systems this heat typically dissipates to the ambient environment through the power distribution panel at a rate sufficient to ensure reliable operation of the power distribution system. In certain types of power distribution panels, heat generated by the contactor dissipates through a circuitous path including one or more contactor leads, interconnects, and bus bars. The bus bars in turn transfer the heat to the ambient air by convection and/or radiation. Depending on the amount of heat generated by the contactors, conventional power panels can include forced convection to dissipate heat. Alternatively or additionally, the bus bars can be sized or include material suitable for operation at elevated temperature to maintain an elevated temperature gradient suitable for transferring heat to the ambient environment. While satisfactory for its intended purpose, the heat rejection requirements for conventional bus bars can require that the bus bars be oversized. The heat rejection requirement can also render conventional bus bars heavier than otherwise necessary, make the bus bars more complex, or require fans and ductwork for forced air cooling systems.

With reference toFIG. 3, contactor102is shown. Contactor102includes a housing108, generator-side leads112and power-consuming device leads114(shown inFIG. 4). Interconnects110couple generator-side leads112to power-consuming device bus bars106through contactor102. As illustrated, contactor102is a three-phase contactor with an A phase, a B phase, and a C phase, (e.g. a first phase, a second phase, and a third phase) with reference numeral suffixes identifying respective phases. It is to be understood that embodiments of the devices described herein can be used in other types of applications, such as dual phase or single-phase applications.

With reference toFIG. 4, interconnect110is shown in a schematic side view. Interconnect110includes a lead post116, a bus bar post118, and a plurality of electrically conductive heat rejection components120. Heat rejection components120for a cooling fin structure connected between lead post116and bus bar post118. Lead post116in turn connects contactor102through power-consuming device lead114. Bus bar post118connects to power-consuming device bus bar106. Epoxy plate121lead post116and provides structural support for the illustrated assembly including contactor102. As illustrated, heat rejection components120are geometrically parallel with one another and orthogonal with respect to lead post116and bus bar post118.

Lead post116is connected electrically in series to bus bar post118by heat rejection components120. Heat rejection components120are electrically connected in parallel with one another between lead post116and bus bar post118for conducting current therebetween. In this respect heat rejection components120present multiple parallel current flow paths between lead post116and bus bar post118. In the illustrated embodiment interconnect110has five heat rejection components with substantially the same conductivity, thereby apportioning current such that about 20% of current moving between lead post116and bus bar post118traverses each heat rejection component120. It is to be understood that interconnect110can include fewer or more heat rejection components as suitable for an intended application.

Each heat rejection component120has an upper surface122and an opposed lower surface124(only one set of these surfaces identified inFIG. 4for purposes of clarity). Upper surface122and lower surface124extend between lead post116and bus bar post118such that opposed upper and lower surfaces of adjacent heat rejection components120and portions of lead post116and bus bar post118define a plurality of respective coolant flow passage126(only one identified inFIG. 4for clarity purposes) therebetween and extending through interconnect110.

When contactor102is in the on-state, heat generated within housing108conducts out of housing108through power-consuming device lead114, into lead post116, and into heat rejection components120. Heat rejection components120have a greater surface area than lead post116for a given electrical cross-section and therefore reject heat to ambient air in the vicinity of upper and lower surfaces122and124, thereby dissipating a greater portion of the heat generated by contactor102than lead post116. In embodiments, heat rejection components120reject substantially all heat generated by contactor102that is not dissipated to the ambient air through housing108and lead post116. In certain embodiments, for environmental conditions where ambient air temperature of about 70 degrees Celsius during which interconnect110carries about 350 amps, interconnect110exhibits a voltage drop of about 150 millivolts and passively dissipates about 26 watts. Heat rejection can be further enhanced by active cooling, i.e. by forcing coolant through coolant flow passage126.

In embodiments, interconnect110is formed from a plurality of relatively thin layers joined to one another. For illustration purposes,FIG. 4shows a first layer130integrally connected to a second layer132and a third layer136by a weld134. At least one of first layer130and second layer132can form respective portions of at least two of heat rejection component120, lead post116, and bus bar post118. Third layer136can be integral with one of power consuming device lead114and power-consuming device bus bar106through weld134. Weld134can be an ultrasonic weld formed using an ultrasonic welding process. Suitable examples of processes for joining layers to form interconnect110include high-power ultrasonic additive manufacturing (UAM) sonic welding processes, such as those available from Fabrisonic LLC. of Columbus, Ohio. UAM allows for integrally joining layers of dissimilar materials into integral structures having interleaved structures. In certain embodiments, posts and/or heat rejection components include sheets of copper or copper alloy materials with bus bars and/or contactor leads include sheets of aluminum or aluminum alloy materials ultrasonically welded to one another and interleaved to form an integral interconnect structure.

With reference toFIG. 5, current, heat and coolant flows associated with interconnect110are shown. With respect to current, a first current flow i1(illustrated as a solid arrow) enters interconnect110through power-consuming device lead114, traverses lead post116, and forms a plurality of second current flows i2(illustrated as solid arrows) that respectively traverse heat rejection components120. Second current flows i2flow to bus bar post118, converge, and form a third current flow i3(illustrated as a solid line arrow) having similar magnitude as first current flow i1.

Heat generated by current flowing through contactor102(shown inFIG. 3) conducts into power-consuming device lead114as a first heat flow H1(illustrated as a dashed arrow). First heat flow H1conducts from power-consuming device lead114into lead post116. From lead post116, first heat flow H1conducts into heat rejection components120as second heat flows H2(illustrated as dashed arrows). As second heat flow H2traverses respective heat rejection components120it radiates and/or convects into the surroundings of interconnect110, thereby generating a third heat flows H3(illustrated with dashed arrows), thereby dissipating into the ambient environment. This allows for power-consuming device bus bar106to be formed from a material constrained only by an intended current flow instead of both current flow and heat rejection requirements, potentially allowing for use of aluminum or aluminum alloy materials (e.g. 6061 aluminum alloy) instead of heavier copper or copper alloy materials. This can potentially reduce the size and/or weight of the power distribution system.

Optionally, dissipation into the ambient environment can be with the assistance of a coolant flow C provided through coolant flow passage126between adjacent heat rejection components120. This can increase the rate of heat dissipation into the ambient environment.

In embodiments, interconnect110forms a heat sink cooled by natural convection cooling of contactors without requiring additional cooling fans, thermal bridging, or heat sinks. This can allow for the use of lightweight contactors for high current applications without requiring fans, fan controllers or other additional components and weight. In certain embodiments, interconnect110provides power-consuming bus bar lead temperature reduction of about 90 degrees Celsius in comparison with conventional interconnect arrangements.