Aircraft high current switch module

A switch module includes a first single-throw switch having a first input terminal 20 switchable to a common terminal. A second single-throw switch has a second input terminal switchable to the common terminal. A first control is coupled to the first single-throw switch and a second control is coupled to the second single-throw switch. The first and second controls are configured to independently control, respectively, the first and second single-throw switches.

BACKGROUND

High current electrical networks, such as the primary system in an aircraft electrical system, can utilize an individual single-throw switch for each switchable branch connecting an element in the network. The single-throw switch can conduct tens or hundreds of amperes from one or more sources of electrical power to various essential and non-essential loads in the network. Each switch can often be connectorized and/or rack mounted.

Unfortunately, each switch can require a custom design in a network having many individual switches, thereby increasing cost and complexity. Additionally, each switch can require at least two high-current connector terminals for connecting the switched element, each connector terminal posing a risk to a reliability of the network should the terminal fail. The individual switch can also include a custom housing that retains the connector terminals, protects the switch, and/or occupies a finite volume in the aircraft electrical system.

SUMMARY

In one aspect, there is disclosed a switch module which can comprise a first single-throw switch having a first input terminal switchable to a common terminal. A second single-throw switch can have a second input terminal switchable to the common terminal. A first control can be coupled to the first single-throw switch and a second control can be coupled to the second single-throw switch. The first and second controls can be configured to independently control, respectively, the first and second single-throw switches.

In another aspect, there is disclosed a method of interconnecting a plurality of elements in a network having at least two switchable branches. The method can comprise identifying a network node where a first switchable branch connecting a first element meets a second switchable branch connecting a second element. The method can further include configuring a switch module with a first single-throw switch having a first input terminal and a second single-throw switch having a second input terminal. The first and the second single-throw switches can be connected in series at a common terminal. The method can further include locating the common terminal of the switch module at the network node, connecting the first input terminal to the first element, and connecting the second input terminal to the second element.

In yet another aspect, there is disclosed an aircraft which can comprise a network having at least two switchable branches. The aircraft can include a network node where a first switchable branch connecting a first element meets a second switchable branch connecting a second element. A switch module can have a first single-throw switch with a first input terminal connected to the first element and can have a second single-throw switch with a second input terminal connected to the second element. The first and the second single-throw switches can be connected in series at a common terminal. A first control can be coupled to the first single-throw switch and a second control can be coupled to the second single-throw switch. The first and second controls can be configured to independently control, respectively, the first and second single-throw switches.

DETAILED DESCRIPTION

FIG. 1illustrates an electrical network30comprising a plurality of elements32connectable by at least two switchable branches34. The at least two switchable branches34can each selectively connect at least one of the plurality of elements32to one of a plurality of network nodes36. Each of the network nodes36can be defined as the place where two or more switchable branches34electrically meet. For example,FIG. 1illustrates ten switchable branches34connecting the plurality of elements32through network nodes36. Each element32can be a source of electrical power such as a left or right generator50, a battery52, or a secondary source54. Each element32can also be a load such as a left or right primary load40, a left or a right secondary load42, or a left or right starter44. Each of the switchable branches34can be implemented as an individual single-pole or multi-pole switch, depending on the number of conductors being switched through the switchable branch.

A bus bar56can function as one of the network nodes36and can comprise a low resistance conductor for receiving power from at least one source of electrical power in the network30, such as one of the generators50, and delivering the received power to at least two other elements32in the network, such as one of the primary loads40and one of the secondary loads42. The resistance of each bus bar56can be considered to be approximately zero ohms compared to a resistance of a load, such as one of the secondary loads42, since the electrical meeting point between two switchable branches34meeting at the bus bar56is essentially the same anywhere along the bus bar56and thus forms one network node36. The bus bar56can also be considered to be an element32, and a switchable branch34can switch the bus bar56to another network node36or to another bus bar.

Continuing withFIG. 1, the electrical network30can be, but is not limited to, a primary system of a high current aircraft electrical system. For example, the primary system can be a 28V direct current (DC) primary electrical system for a small to medium twin-engine aircraft. The primary system can also be an alternating current (AC) primary electrical for a commercial or military aircraft, such as a three-phase AC system. Loads within the primary system of the aircraft can include essential and non-essential loads. Each switchable branch34can be of custom design to accommodate a high current flow that is unique from other switchable branches in the electrical network30. The electrical network30can also apply to ground transportation, rail, or marine applications where high current electrical power distribution is required.

Each of the switchable branches34can be individually packaged and connectorized. The electrical network30can be configured via switchable branches34for a variety of operating modes, such as energizing one of the starters44or bridging a left bus bar56to a right bus bar56. The primary loads40can be considered essential loads and can be energized directly by one of the bus bars56. For example, in an aircraft, the primary loads40can each be, but are not limited to, a galley load, an electro-thermal airframe de-icing systems, or a transformer rectifier unit (TRU). The secondary loads42can be considered non-essential loads and can be energized through one of the switchable branches34. Examples of secondary loads42can be, but are not limited to, avionics equipment, exterior lighting, and cabin lighting.

The secondary source54can be a ground power supply supplying power to electrical network30from a terrestrial power supply (not shown). For example, secondary source54can be a terrestrial power supply positioned at an airport terminal adjacent to an aircraft parked for loading and unloading the aircraft. In alternate applications, the secondary source54can be a battery or a power supply positioned at a trucking yard, rail yard, or marine harbor for supplying power to a ground, rail, or marine application.

Referring now toFIG. 2, in various aspects of the present disclosure, a switch module10can comprise two single-throw switches12connected in series and each having an input terminal20switchable to a common terminal26at the series connection. The A and B single-throw switches12can each have a control14(A or B, respectively) to control the switching of the single-throw switch12independent of the other single-switch in the switch module10. In an aspect illustrated inFIG. 2, each single-throw switch12can be a single-pole single-throw (SPST) switch closing or opening a circuit for one conductive pathway. The common terminal26and at least one of the input terminals20can be configured to connect to one of a source of electrical power or a load.

The switch module10can be an aircraft high current switch module configured for a primary system of an aircraft electrical system. For example, the switch module10can be designed to suit a high current or environmental specifications unique to the aircraft electrical system. At least one of the single-throw switches12can be a solid state switch such as a MOSFET or other device. The solid state switch12can be unique to an aircraft specification such as temperature, shock, vibration, current rating, protection against transient signals, operating voltage, or operating current. The single-throw switch12can also be an electromechanical switch such as a relay or circuit breaker and can be controlled by control14.

At least one of the single-throw switches12can be bidirectional for passing current in both directions. For example, a bidirectional switch can be a Triac, relay, or other device configured to pass the voltages and currents particular to an aircraft electrical network when controlled by control14. Alternatively, one or more of the single-throw switches12can be unidirectional, such as a silicon controlled rectifier (SCR) having unidirectional properties.

Referring now toFIG. 3, in various aspects of the disclosure, the switch module10can include a current measuring device16in series with each of the single-throw switches12. The current measuring device can include a small series resistor across which a voltage is measured, a Hall Effect sensor, or other components known in the art. The current measuring device16can be monitored by a control circuit (not shown) to verify the open/close state of single-throw switch12or to detect operating conditions that exceed the specifications of the switch module10. Alternatively, the switch module10can include the current measuring device16in series with only one of the single-throw switches12.

Referring now toFIG. 4, in various aspects of the disclosure, the switch module110can include three single-throw switches112(A, B, and C) each having its own input terminal120switchable to a common terminal126and having an independent control114control (A, B, or C, respectively). As inFIG. 2, each single-throw switch12can be a single-pole single-throw (SPST) switch closing or opening a circuit for one conductive pathway.

Referring now toFIG. 5, in various aspects of the disclosure, the switch module210can comprise two multi-pole single-throw switches213(A and B) each comprising three single-pole single-throw switches212each having an input terminal (220,221, or222) switchable to a common terminal (226,227, or228, respectively). The multi-pole single-throw switches213can each have an independent control114(A or B). For example, switch module210can comprise two single-throw switches each capable of selectively switching a three-conductor signal, such as a three-phase AC signal, to the common terminals226,227, and228.

Switch module210can further comprise a housing230enclosing the single-pole single-throw switches212. In embodiments not shown, the housing230can also be included in the switch module10(FIG. 2-3) or110(FIG. 4) enclosing the single-throw switches12or112, respectively. At least one of the common terminals (226,227,228) or input terminals (220,221,222) can be mounted to the housing230for relieving a strain imposed on the mounted terminal when connecting or disconnecting a cable or conductor (not shown) from the switch module210. The switch module210can be rack mounted, and the housing230can be configured to mount to a rack (not shown).

Alternatively, the switch module210can be configured for rack mounting and the housing230can be mounted to the switch module210. At least one of the input (220) or the common226terminals can include a connector (not shown) for connecting the one or more terminals (220,226) of the switch module210to a primary electrical system of an aircraft by hand. For example, the input and common terminals of the switch can be a sliding plug or jack having a low contact resistance, similar in principle to the common banana plug, for quick installation and repair of the switch module.

Referring toFIGS. 2-5, the input and common terminals can be connectorized for quick installation and repair without a tool. The switch module (10,110,210) can also include a mounting frame (not shown) holding the single-pole switches in alignment for connecting or soldering the input and common terminal to a printed circuit board. The switch module can be applied to any small to medium sized commercial or private aircraft, and to large commercial passenger aircraft. Beneficially, the connection corresponding to common terminals (26,126,226) and between the two or more single-throw switches in the switch module are internal and can thereby eliminate an external terminal or connector in electrical network30. The switch module could also be used in ground or sea applications where high-current electrical power distribution is required, particularly where high current switches are individual modules that are connectorized.

Referring now toFIG. 6, in various aspects of the disclosure, the elements32in the network ofFIG. 1can be interconnected using a plurality of switch modules10ofFIG. 2to implement the switchable branches34. Each of the network nodes36can be defined as the place where two or more switchable branches34electrically meet. A common terminal26of each of the switch modules10can be located at one of the plurality of network nodes36. In the illustrated example ofFIG. 6, five switch modules10having a total of five common terminals26are used to implement the switch topology ofFIG. 1by locating common terminals26at network nodes36. Alternate arrangements of switch modules10can exist to implement the switch topology ofFIG. 1, and one is described below forFIG. 7.

Beneficially, a standardized switch module10can be skillfully deployed by assigning the common terminal26to network node36in electrical network30in order to reduce the number of components in the electrical network30. Additionally, if the switch module10includes a housing (230,FIG. 5) enclosing each switch module10, then a reduction in the volume occupied by the switchable branches can be realized. Also, a total of fifteen input and common terminals ofFIG. 6can represent a 25 percent reduction in the number of switch terminals needing connection within electrical network30compared to the twenty terminals required inFIG. 1, and thereby can improve the reliability of electrical network30.

Continuing withFIG. 6, in various aspects, the battery bus bar56can be simplified to tie only three components together (the three upper switch modules10) since some of the connections to the battery bus bar56are now absorbed within the three upper switch modules. This can be a smaller number of connections than the six connections required for the individual single-throw switchable branches34ofFIG. 1.

In aspects not shown, a switch module can be designed to include three single-throw switches each having an input terminal switchable to a common terminal with the advantage that greater economies of scale and compactness can be achieved over the two-switch module10illustrated inFIG. 6. In applying a three-switch embodiment of the switch module to electrical network30, network nodes can be identified where three or more switchable branches meet electrically, and then the common terminal of the switch module can be located at the network node. However, it may occur that at least one of the single-throw switches in at least one of the three-switch modules will be unused, such as when a network node connects to only two switchable branches. For example, the switchable branches ofFIG. 1can be replaced by four switch modules each containing three single-throw switches (instead of the five switch modules ofFIG. 6), and can result in a total of two single-throw switches being unused.

Referring now toFIG. 7, in various aspects of the disclosure, another arrangement of interconnecting the plurality of elements32inFIG. 1is shown using the switch module10ofFIG. 2. An alternate selection of network nodes36can be identified which, when assigned to the common terminals26of switch module10ofFIG. 1, fully instantiate the switch topology ofFIG. 1without leaving unused single-throw switches12. Note that the number of elements32and switch modules10connected to each of the left and right bus bars56decline from four connections inFIG. 1to three connections inFIG. 7. This implementation of switch modules10inFIG. 7can absorb five of the20terminal connections ofFIG. 1and can lead to a 25 percent of reduction in the terminal connections in electrical network30.

Additional configurations of switch module10are possible, and can beneficially accommodate other constrains in a high current distribution system, such as wiring particulars and the location of various elements32. For example, referring toFIG. 7, the left side starter44and the battery52may be located close to each other in the aircraft and form a more convenient node for implementing switch module10than the battery52and the secondary source54.

FIG. 8illustrates a second electrical network31which can comprise eight elements32and two bus bars56connectable by eight switchable branches34. Sources of electrical power include three generators50and the secondary source54. Electrical loads include two primary loads40and two secondary loads42. Each of the switchable branches34can represent an individual multi-pole switch switching an AC signal having two or more conductors. A bus tie58can tie two or more bus bars56together for the purpose of providing redundancy should the left or right side fail in the electrical network31.

The bus tie58can function as one of the network nodes36and can comprise a low resistance conductor for receiving power from at least one source of electrical power in the network30, such as one of the generators50, and delivering the received power to at least two other elements32in the network, such as the left and right bus bars56.

Referring now toFIG. 9, in various aspects of the disclosure, the elements32in the network ofFIG. 8can be interconnected using a plurality of switch modules10ofFIG. 2to implement the switchable branches34. The common terminal26of each switch module10can be located at one of the plurality of network node36formed between two switchable branches being instantiated by the switch module10. In the illustrated example ofFIG. 9, four switch modules having a total of four common terminals26can be used to implement the switch topology ofFIG. 8. Alternate arrangements (not shown) of switch modules10can be employed to implement the switch topology ofFIG. 8, and may or may not result in one or more unused single-throw switches20.

Bus tie58can be absorbed by the switch module10in the center ofFIG. 9. The total number of input terminals20and common terminals26can be reduced from the sixteen terminals ofFIG. 8to the twelve terminals ofFIG. 9. In an alternate configuration not shown, switch modules having three or more single-throw switches can be configured to implement the switch topology ofFIG. 8.

Many other possible embodiments and configurations in addition to that shown in the above figures are contemplated by the present disclosure. To the extent not already described, the different features and structures of the various embodiments can be used in combination with each other as desired. That one feature cannot be illustrated in all of the embodiments is not meant to be construed that it cannot be, but is done for brevity of description. Thus, the various features of the different embodiments can be mixed and matched as desired to form new embodiments, whether or not the new embodiments are expressly described. Moreover, while “a set of” or “a plurality of” various elements have been described, it will be understood that “a set” or “a plurality” can include any number of the respective elements, including only one element. Combinations or permutations of features described herein are covered by this disclosure.