Rotary relay contactor

A contactor with a rotary actuation system, the contactor including a plurality of switching devices configured to switch a plurality of electrical circuits, a plurality of cam followers each operably coupled to one of the switching devices, wherein each cam follower is configured to actuate a switching device, and a cam mechanism, the cam pivotally attached to a point rotation, the cam having plurality of lobes about its perimeter, the cam in operable communication with each cam follower such that upon rotation of the cam mechanism, each cam follower engages a lobe of the plurality of lobes, it causes each cam follower to actuate the respective switching device. The contactor also includes an actuator connected to the cam, the actuator responsive to a control current and operable to rotate the cam and a controller, the controller operable to supply a control current the actuator.

BACKGROUND

The present disclosure relates to controllers, and contactors for switching power sources and loads associated with them, in particular, a rotary contactor for control of power circuits and components on an aircraft.

Vehicles, such as aircraft, typically utilize one or more electronic control unit(s) (ECU) and/or Solid State Power Controllers (SSPC), various sensors, and actuators in various control applications to ensure inflight operation, provide for redundancy, and fail-operational capabilities. A primary function performed by controllers is power control and/or distribution. Electrical systems typically include an electrical power source, which powers a corresponding distribution circuit through a controllable power contactor that selectively interlinks a multitude of distribution circuits. Each distribution circuit is powered by its own source through a corresponding power contactor, however, should a source become defective, the distribution circuit can be powered by the source of another distribution circuit through at least one contactor. Distribution systems of this type are often utilized onboard aircraft. In this environment, each distribution circuit generally powers a distribution bus, which then powers a plurality of electrical loads. Each power source is typically either of a generator driven by an engine of the aircraft, an auxiliary power unit, batteries, and the like.

The contactors reside in a power panel assembly on a primary bus bar structure located within an aircraft electronics bay. The primary bus bars interface to the contactors through terminal posts, assuming it is a 3 phase, AC contactor. In addition to the primary power interfaces, a low power signal connection is required for control and sensing functions. Because the contactors are line replaceable modules (LRMs) each contactor must have an individual chassis to support a multitude of electrical components and wiring harnesses which connect the LRM to the power panel assembly. Moreover, the contactors typically include a harness to provide the interfaces for control and signals. During LRM replacement, tooling is required to remove connectors and large tooling is required to remove fasteners on the primary power interfaces. These interfaces also require a controlled re-torquing procedure and calibrated torque wrench during LRM replacement. Although effective, these features result in a relatively complex LRM that reduces reliability and may result in increased maintenance considerations when located within an aircraft environment.

Furthermore, the present standard for physical implementation of relays and contactors, employs a linear actuator with a cylindrical form e.g., linear solenoid, for the motor drive to switch the internal electric contacts. In the present state of the art regarding electromechanical contactors, the motor structure, and housing is a design driver for the size of the contactor. In aircraft power distribution systems, these form factors are large and not readily implemented in quick line replaceable modules. In order to change the form factor of the relay or contactor assembly to flatten the assembly rather than being generally cylindrical, a new actuator system design is necessary.

Accordingly, it is desirable to provide an uncomplicated line replaceable module with a contactor that is configured to fit with the line replaceable module and minimum of wire harness connections in order to reduce maintenance considerations when located within an aircraft environment.

SUMMARY

According to one embodiment described herein is a contactor with a rotary actuation system, the contactor including a plurality of switching devices configured to switch a plurality of electrical circuits, a plurality of cam followers each operably coupled to one of the switching devices, wherein each cam follower is configured to actuate a switching device, and a cam mechanism, the cam pivotally attached to a point rotation, the cam having plurality of lobes about its perimeter, the cam in operable communication with each cam follower such that upon rotation of the cam mechanism, each cam follower engages a lobe of the plurality of lobes, it causes each cam follower to actuate the respective switching device. The contactor also includes an actuator connected to the cam, the actuator responds to a control current and operable to rotate the cam and a controller, the controller operable to supply a control current the actuator.

In addition to one or more of the features described above, or as an alternative, further embodiments of the rotary actuation system may include that the plurality of switching devices includes at least one of a single pole and a multi-pole switch.

In addition to one or more of the features described above, or as an alternative, further embodiments of the rotary actuation system may include that the plurality of switching devices includes at least three switches, each switch configured to switch a phase of three-phase power.

In addition to one or more of the features described above, or as an alternative, further embodiments of the rotary actuation system may include that the cam mechanism is a polygon wherein each vertex forms one lobe of the plurality of lobes.

In addition to one or more of the features described above, or as an alternative, further embodiments of the rotary actuation system may include that the polygon has at least three vertices.

In addition to one or more of the features described above, or as an alternative, further embodiments of the rotary actuation system may include that the polygon is a hexagon.

In addition to one or more of the features described above, or as an alternative, further embodiments of the rotary actuation system may include that a lobe of the plurality of lobes includes a profile configured to cause latching or hysteresis of the rotation of the cam.

In addition to one or more of the features described above, or as an alternative, further embodiments of the rotary actuation system may include that the actuator is configured to rotate the cam mechanism a selected angular displacement.

In addition to one or more of the features described above, or as an alternative, further embodiments of the rotary actuation system may include that the actuator is a rotary actuator.

In addition to one or more of the features described above, or as an alternative, further embodiments of the rotary actuation system may include that the rotary actuator is configured has a ferromagnetic stator assembly and a ferromagnetic rotor assembly, the stator assembly configured as an arcuate (bow shaped) annular segment and the rotor configured as a sector, the rotor fixed to the cam mechanism.

In addition to one or more of the features described above, or as an alternative, further embodiments of the rotary actuation system may include that the stator assembly includes a stator core having at least two stator teeth and a slot therebetween and a stator coil disposed in the slot.

In addition to one or more of the features described above, or as an alternative, further embodiments of the rotary actuation system may include that the at least one of the stator assembly and the rotor assembly includes ferromagnetic materials including, but not limited to steel laminations, sintered magnetic powder material, or solid ferromagnetic material such a steel.

In addition to one or more of the features described above, or as an alternative, further embodiments of the rotary actuation system may include that the actuator is a linear actuator, the linear actuator having a ferromagnetic stator assembly with a control coil and a piston operably connected to the cam mechanism and configured to rotate the cam mechanism when the linear actuator is activated.

In addition to one or more of the features described above, or as an alternative, further embodiments of the rotary actuation system may include that the linear actuator is a solenoid.

In addition to one or more of the features described above, or as an alternative, further embodiments of the rotary actuation system may include a return spring operably connected to at least one of the actuator or the cam mechanism, the return spring operable to return the cam mechanism to a first position corresponding to the plurality of switching devices being inactive.

In addition to one or more of the features described above, or as an alternative, further embodiments of the rotary actuation system may include that the contactor with a rotary actuation system is configured as a modular line replaceable wherein the plurality of switching devices are distributed at radial points about the perimeter of the cam resulting in a flatter form factor than existing linear contactors.

In addition to one or more of the features described above, or as an alternative, further embodiments of the rotary actuation system may include that the contactor with rotary actuation system is configured for a standard rack mount installation.

Also described herein in another embodiment is an aircraft power distribution system including a power source supplying power to a control unit and a load receiving power from the control unit. The power system also including that the control unit includes a circuit board supporting rack mount plug-in connection and a contactor with a rotary actuation system supported by the board, the contactor configured to selectively provide power from the source to the load in response to a control command.

Additional features and advantages are realized through the techniques of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered a part of the claimed disclosure. For a better understanding of the disclosure with the advantages and the features, refer to the description.

DETAILED DESCRIPTION

For the purposes of promoting an understanding of the principles of the present disclosure, reference will now be made to the embodiments illustrated in the drawings, and specific language will be used to describe the same. It should nevertheless be understood that no limitation of the scope of this disclosure is thereby intended. The following description is merely illustrative in nature and is not intended to limit the present disclosure, its application or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features. As used herein, the term controller refers to processing circuitry that may include an application specific integrated circuit (ASIC), an electronic circuit, an electronic processor (shared, dedicated, or group) and memory that executes one or more software or firmware programs, a combinational logic circuit, and/or other suitable interfaces and components that provide the described functionality.

In general, embodiments herein relate to an application of a method and/or system for an electromagnetic mechanical relay/contactor actuator design with a rotary actuation system to open and close the moveable electrical contact (or contacts). The rotary actuation system provides a flattened, non-cylindrical form factor compared to legacy configurations to optimize installation and integration of the relay contactor assembly into a plug in line replaceable module. In an embodiment, the module assembly would incorporate an actuation motor that is not linear but configured to impart a rotational motion to actuate an electrical contact assembly and provide actuation at the electrical contacts. The rotary actuator relay/contactor operates in a similar fashion to an axially constructed (linear actuated) contactor, except that the electromagnetic actuator in the rotary actuation system creates a rotary motion, and closes contacts arrayed at radial points circumferentially about the axis of rotation. In an embodiment, a partial turn e.g., ¼ turn or ½ turn rotary actuation and a linkage facilitates a change in the shape and direction of a motivation force that enables moving the moveable electrical contact and the overall configuration of the device.

Referring toFIG. 1, an aircraft10is shown. Aircraft10includes one or more control systems shown generally as12. The control system12may include a power system13that interconnects with one or more controllers referred to generally as16and more specifically as16l,16rcommonly located at or near each engine14l,14r. Other controllers16are also be depicted in this instance as16a,16b, and the like. In the described embodiments, the reference numerals are annotated with an “l” or “r” to denote the left or right side of the aircraft10, respectively, for the purpose of simplicity of description. Likewise, the annotation “a”, “b”, . . . “n” is employed to simplify designation of a multiple enumeration of a component or element.

Each of the controllers16may be configured to receive various sensor signals from sensors referred to generally as18and individually as18a,18b, . . .18nall over the aircraft10and may also operate one or more actuators shown generally as20, and more specifically as20a,20b,20c, . . .20nto control the operation of the engines14r,14l, flight controls, (not shown), power systems13and the like. In one embodiment, the actuator20may be a contactor hereinafter referred to as contactor20employed for connecting power busses in the power system13. The control system12and power system13may also be operably connected to various other components throughout the aircraft10, including, but not limited to other controllers16, control panels23, displays25, and the like. Some controllers16e.g.,16amay also be configured to receive power from various aircraft sources, e.g., generators, batteries and the like and distribute power as needed to various systems in the aircraft10The power system13may be part of a controller16. In yet another embodiment, the configuration could be the opposite with the controller16operating as or providing a portion of the power system13, as illustrated by the general depiction of16aand described further herein. In an embodiment, the power system13incudes a contactor20with a rotary actuation system100as described herein for routing power to various components in the aircraft10. In an embodiment, a contactor20may be a three-phase contactor20having at least three separate electrical switches or contacts configured to direct power associated with each phase of a three-phase power bus. In one embodiment, the contactor with rotary actuation system100may be part of a modular primary power distribution board such as described in U.S. Pat. No. 8,559,149, the entire contents of which are incorporated herein by reference.

FIG. 2depicts an example rotary actuation system100and contactor20in accordance with an embodiment as may be included in or connected to a controller16as part of the power system13. The rotary actuation system100includes a rotary actuator110operably coupled to an actuation cam mechanism130pivotally fixed a center point of rotation111and a plurality of actuation lobes referred to generally as134and more specifically as134a,134b, and134cdistributed about a perimeter132of the cam130. The rotary actuator110could be considered similar to a segment or section of a motor (e.g. a typical switched reluctance motor or a stepper motor) with a sector shaped rotor section120and a partially annular stator assembly112. The rotary actuator110includes a fixed stator assembly112having a stator core114and an excitation coil118. The rotary actuator110also includes a ferromagnetic rotor section120fixed to the cam130and pivotally attached to the point of rotation111such that the rotor section120is operable to rotate about the point of rotation111and thereby rotate the cam130.

In an embodiment, stator assembly112is a single pole, typically of the single direct current (DC) type, partially circumscribes the rotor section120. The stator assembly112has a plurality of ferromagnetic stator teeth113coupled to a partially annular ferromagnetic stator core114, (two are depicted). A distal end115of each stator tooth113is proximate an outer annular periphery126of the rotor assembly120. In one embodiment, a small outer air gap125exists between the outer annular periphery126and the stator teeth113. The stator assembly112also has a stator coil118mounted in a slot117between the stator teeth113. In an embodiment, the ferromagnetic stator core112and stator teeth113may be constructed of any variety of ferromagnetic materials including, but not limited to iron laminations, sintered magnetic powder material, or solid ferromagnetic material such as iron or steel. In one embodiment, steel laminations are employed. The stator winding118, also called an armature winding, is typically a single DC winding. Though it could be an alternating current configuration as well.

Continuing withFIG. 2, the ferromagnetic rotor assembly120with at least one magnet122disposed in a ferromagnetic rotor core124at the outer periphery126thereof. In an embodiment, the magnet(s)122may be permanent magnets, however other types of magnets may be employed. There may be a portion of the ferromagnetic core124removed forming a slot123. The rotor assembly120may be constructed of any variety of ferromagnetic materials including, but not limited to iron or steel laminations, sintered magnetic powder material, or solid ferromagnetic material such a steel. In one embodiment, steel laminations are employed. In another the rotor assembly120is machined from a steel block. While in the described embodiments the PMs122are arranged in the same orientation as the axis of the center of rotation111for the rotor assembly120, PMs122can be also arranged at greater angle than zero degrees with respect the rotor center of rotation111. Furthermore, while typically a generally rectangular cross section for the teeth122is employed, different cross sections other than rectangular are envisioned. The number of teeth is typically even to create pole pairs. The general operating principle is that the coil induces a magnetic flux in the stator core, and the flux crosses the air gap into the rotor. The magnetic core of the rotor has lower reluctance to the flow of magnetic flux than the air, and this generates a force that draws the rotor core into alignment with the stator core. Alternately, if permanent magnets are attached to the rotor core, the rotor core could be made from non-magnetic materials. The rotor could be a single PM, and the stator a single electromagnet.

Continuing withFIG. 2, the cam mechanism130is depicted as generally a polygon or circular in shape with lobes134arranged about its outer periphery132generally at the vertices. In an example, the cam130is depicted as a hexagon with three lobes134a,134b, and134care depicted at three of the vertices, though any number are possible depending on the configuration of the cam130and rotary actuation system100. For example, a cam130with a greater number of lobes134could be employed, or multiple cams130could be employed. The cam130is generally depicted as a hexagon but other configurations are possible including other polygons, circle, and the like. In an embodiment, while the cam130is depicted as a hexagon, other configurations are envisioned and the configuration depicted is merely for illustration and simplicity for the purposes of describing the embodiments. It should also be appreciated that the profile of the lobes could be configured to provide for a latching function and/or hysteresis function such that once the peak of the profile is attained, any further motion causes the cam to fully rotate thereby latching to the rotated position. The rotary actuation system100also includes a cam follower shown generally as136and specifically as136a,136b, and136ccorresponding to the lobes134a,134b, and134crespectively. The cam follower136is engaged with the surface of the cam130at the periphery132and configured to follow the surface as the cam130rotates. The cam follower136converts the rotary motion of the cam130to a linear displacement configured to actuate a switching device shown generally as140and specifically as140a,140b, and140crespectively associated with the cam followers136a,136b, and136c. In an embodiment a the switching device140is depicted as a simple single throw single pole switch, however other configurations are envisioned and the configuration depicted is merely for illustration and simplicity. For example, while in one embodiment three single pole switches are employed and configured to switch each phase of a three-phase power source, in other configurations, the switching device could be a single device with multiple poles such as might be employed to switch each phase of a multiphase power source.

In operation, controller16provides a control current Icthe stator coil118. When the coil118is fed with a current, a magnetic flux (Φg) is generated in the stator assembly112, that then interacts magnetically with the ferromagnetic material of the rotor. When a control current Icis applied to the stator coil118, the magnetic circuit formed between the teeth113of the stator assembly112and the rotor assembly120results in the flux crossing the airgap125to align the lines of magnetic flux. As a result, a force will be imparted on the rotor assembly, which will then rotate to align the rotor assembly120, with the teeth113of the stator assembly112. As a result, the cam130is rotated clockwise engaging the lobes134with the cam followers136in a manner such that the switching devices140are activated and providing continuity across the terminals of the switching devices140in the example as depicted. In an embodiment the application of the control current causes the cam to rotate a selected angular displacement e.g., approximately 20°-30° for the cam130shown. However, other angular displacements are possible. Moreover, depending on the configuration of the actuator110, small angular step for each application of control current may be employed with successive/repeated applications incrementing the angular displacement to activate the switching devices. When a spring return150is operably connected to the cam130to ensure that the cam returns to its original position when the control current Icis removed. While the spring150is depicted as linear with an attachment near the periphery132of the cam130, other configurations are possible. For example, a coiled torsion spring about the center of rotation111could also be employed for simplicity.

FIG. 3depicts another possible embodiment and configuration for the rotary actuation system shown generally as200. In this embodiment, the rotary actuation system200employs a linear electromechanical actuator210(e.g. relay or solenoid) comparable to the rotary actuator110of the previous embodiment. In this embodiment the electromechanical actuator210has a fixed stator/coil/armature assembly212with a coil218and a movable ferromagnetic piston220(comparable to the rotor assembly120above) operably connected to the cam130and the spring150. The piston220is operably connected to the cam130such that actuation of the piston in a left-right direction as shown imparts a rotation to the cam130as needed so that the switching devices140are activated as described above.

In operation, for this embodiment once again controller16provides a control current Ic the stator coil218. When the coil118is fed with a control current Ic, a magnetic flux (Φg) is generated in the stator assembly112, that then interacts magnetically with the ferromagnetic piston220. As a result, a force will be imparted on the piston220assembly, which will then compress the spring150and rotate the cam130. Once again, the cam130is rotated clockwise engaging the lobes134with the cam followers136in a manner such that the switching devices140are activated and providing continuity across the terminals of the switching devices140in the example as depicted. When the control current Icis removed, the spring150returns the piston220and the cam130to its original position. Once again, while the spring150is depicted as linear with an attachment near the periphery132of the cam130, other configurations are possible. For example, a coiled torsion spring could also be employed for simplicity.

It should be appreciated that the described embodiments present a unique design for a high current line replaceable unit configured contactor or switching device uniquely configured to be integrated with a circuit board or modular replaceable assemblies such as a modular or rack mounted type configuration power control unit. Advantageously, the rotary actuation enables configuration of a high current switching device in a flatter, modular form factor, thereby avoiding the large cylindrical form factor typical of high current devices (e.g., solenoids). For example the radial layout of the electrical contacts of the switching devices140results in a decreased depth of the contractor apparatus compared to conventional contactors and as a result facilitates installation of the rotary actuation system100as or in a line replaceable unit. This flatter actuator and modular approach allows the heat dissipation in the electric contacts (examples140a,140b, and140c) to be sunk to the installation mounting frame, so that the electrical bus bar is not the primary heat sink for thermal losses due to contact voltage drop.