Aircraft power system

Abstract

An electrical power outlet (O1,O2,O3) for a passenger aircraft has a connector for connection to a personal electronic device (PED); a transceiver to output, and receive, power status update signals t

Description

Technical Field The present invention relates to power distribution systems in a passenger aircraft. Background We have devised a novel system for managing power distribution to a plurality of passenger power outlets (such as in-seat power outlets) in a passenger aircraft. Summary According to a first aspect of the invention there is provided an electrical power outlet for a passenger aircraft, the outlet comprising: a connector for connection to a personal electronic device, PED; a transceiver to emit a power status update signal, and to receive power status update signals from other outlets; a processor, which is configured to be capable of managing power delivered by the outlet in response to power status update signals received from one or more other outlets. By PED, we include, but do not limit to, mobile phones, tablet computers, laptops, notebooks, as well as other electronic devices. The processor may be configured to ensure that the maximum capacity of each power convertor and / or each power supply line, and / or the maximum power capacity of the aircraft electrical supply, is not exceeded or any excess is reduced, by regulating the power delivered by the outlet. These may be termed power budgets. Where there is a system with multiple power outlets in use, the power supplied by one or more individual outputs can be tailored (for example, reduced) and so ensure that total power delivered by the multiple outlets is within, or closer to, the predetermined power delivery capacity of the overall system, or respective part thereof. In broad terms, the outlet can communicate its power status to other outlets and can receive, process and take regulating action based on power status information from other outlets, taking account of predetermined power delivery rules / constraints. The processor may be configured to determine an instantaneous power consumption value some or all of other outlets in a system / network of power outlets. The processor may be configured to determine total power being consumed by one or more of the following: the or all outlets which share a common power converter, the total power being consumed by all outlets which receive power from a respective power supply line, and the total power being consumed globally by all outlets in the system / network. The processor may be configured to compare a determined power consumption value to a determined maximum permissible power value of at least one of: the aircraft supply; the power supply line; the power convertor; the outlet. The memory of the outlet may be configured to store one or more of the following: a power converter group identifier, that the outlet is part of; an outlet identifier of the group; a maximum power output of a power converter; a maximum power capacity of aircraft power supply; a power supply line number / identifier; a power supply line power capacity; a power allocation priority (e.g. the extent to which the outlet can be prioritised for higher / enhanced power allocations than outlets with lower priority); and a maximum power output limit of the outlet (which may be one of several preset options, one of which is selectable during a set-up procedure). The memory may store power management rules, which when applied, determine whether modification of power delivered (to a PED) by the outlet is required. The rules may include one or more of the following values: maximum power capacity of the overall aircraft power supply, maximum power capacity of a power supply line, maximum power capacity of a power convertor, and maximum power deliverable by the outlet. Possible actions brought about by the processor after having applied the power management rules may include at least one of the following: reducing power delivered by the outlet, increasing power delivered by the outlet, maintaining a power level delivered by the outlet. The processor may be configured to use stored data relating to power consumption of the system, or one or more parts thereof, when applying the power management rules. The memory may store at least one decision tree, which is executed by the processor to determine if any action needs to be taken, such as to reduce the power supplied by the outlet, and to what extent. The decision tree may comprise a sequence of processing steps which implement power management rules of the system. The decision tree may require a comparison of power delivery values of some or all of the system (of which the outlet is part) to maximum power delivery values. The steps for each outlet may include one or more of the following: power delivered by a respective power converter, power delivered by a power supply line, and power delivered to the entire system. Each step may include comparison to a respect power budget (e.g. a predetermined maximum power delivery value). For each such step, there may be one more sub-steps, which further relate to generating a decision to control of power delivered to the outlet, based on aspects of the power management rules. Said sub-steps may include one or more of the following: power delivered by the outlet, a power priority allocation of the outlet, and length of time during which power has (continuously) be delivered by the outlet. Each step and sub-step may include a decision which is responsive in the affirmative or in the negative. In broad terms, the processor may be configured to control power delivered by the outlet. The processor may be arranged to store in the memory power values contained in received power status update signals received from other outlets in the system, and which relate to power delivered by each of those outlets. The processor may be arranged to perform calculations using the stored power values relating to other outlets, and may do so on a continual or repeated basis. The calculations may include summing stored power values of some or all of other outlets. The memory may be arranged to store power values of other outlets in tabular format. The processor may be configured to (repeatedly / continually) determine an instantaneous cumulative value of power consumption for different parts / subsets / entirety of the system. For example, the processor may be configured to calculate a power delivery value of a power converter, to which the outlet and other outlets may be connected, which value may be determined by summing the power delivery values of all power outlets which are supplied by the power convertor. The processor may be configured to calculate a power delivery value of a power supply line to which the power converter is connected, which may be determined by summing the power delivery values of all power converters connected to the power supply line (which is given by the sum of all power delivery values of power outlets connected to said power convertors). The processor may be configured to calculate a power delivery value of the aircraft power supply, which may be determined by summing the power delivery values of all power supply lines (which is given by summing the power delivery values of all outlets of the system). The power status update signal may comprise / be indicative of characteristics of power supplied by the outlet. The power status update signal may be representative of a prevailing power usage status of the outlet. The power status update signal may include a power value which is requested to be supplied to a device (which is connected to the outlet). The power status update signal may comprise a radio frequency, RF, message. Power status information related to the outlet may be encoded into said signal. The power status update signal may comprise a signal of varying frequency. Said signal may comprise a chirp. The transceiver may be arranged to emit a power status update signal when there is a change of power supply status at the outlet and / or at predetermined time intervals (in the absence of any such change). The transceiver may be arranged to emit a power status update signal in the absence of any power changes at the outlet within a predetermined period. The transceiver may be arranged to output power status update signals across an air interface, but in addition / alternatively, may use power line transmission (i.e. the signals being sent in the electrical domain through the electrical cabling / lines which is used to provide power to the outlets). The electrical power outlet may comprise a connector for achieving a physical electrical coupling with a counterpart connector (of a PED). The electrical power outlet may comprise an electrical socket, or more generally a female electrical connector. The electrical power outlet may, alternatively or in addition, comprise an inductive charging assembly. Whilst the processor and / or the memory may be incorporated as part of the outlet, i.e. an integral physical entity (for example in a single housing if the outlet), one or both may be provided separately from the outlet module / unit, as distinct physical entities but connected to the outlet module / unit. The processor may be configured to execute machine-readable instructions when applying the rules of power management. The machine-readable instructions may be realised as software or firmware. According to a second aspect of the invention there is provided a system of power outlets for a passenger aircraft, comprising: a plurality of power outlets for connection to PEDs; a power supply line for connection to an aircraft electrical supply; one or more power converters connected to the power supply line; the power outlets connected to the at least one power converter, wherein the power outlets are defined in the first aspect of the invention. The system may convey power from the aircraft supply and distribute through one or more power supply lines. It will be appreciated that a ‘power supply line’ is intended to have a broad meaning such that it may comprise one or more electrical cables. Each power supply line may be provided in a conduit, and the combination of the power line in the conduit which may be termed a power column. Each power supply line may provide power to at least one power convertor. There may be multiple power supply lines for connection to the aircraft’s electrical power supply. Each supply line may provide power to one or more power converters. A power convertor may modify / tailor / condition a power supply from an aircraft supply to render the same suitable for use by a power outlet. The power converter may modify-one or more electrical characteristics of the power supply from the aircraft supply, which may include electrical signal type, power, current magnitude and / or voltage magnitude. A power convertor may comprise an AC-DC convertor. The power converter may be termed a power supply unit, which is located downstream from the aircraft power supply, and connected to the power supply line. Each power outlet may be connected to only one power convertor. Multiple power convertors may be connected to a respective power supply line. Each power convertor provides power to at least one power outlet. Where multiple power outlets are serviced by a power convertor, these may form a subset of power outlets within the system. One or more of the power outlets may be configured to deliver power within different predetermined constraints or rules as compared to other outlets. For example, one or more power outlets may be configured to have a different allowed maximum or maximum average power than one or more other power outlets in the system. The system may convey power from the aircraft power supply and distribute through one or more power supply lines. It will be appreciated that a ‘power supply line’ is intended to have a broad meaning such that it may comprise one or more electrical cables. Each power supply line may be provided in a conduit, and the combination of the power line in the conduit which may be termed a power column. Each power supply line may provide power to at least one power convertor. There may be multiple power supply lines for connection to the aircraft’s electrical power supply. Each supply line may provide power to one or more power converters. All outlets of the system may know (e.g. by being stored in respective memories) what all other outlets are doing (i.e. have intimate knowledge of each member of the population of outlets) and know the limits configured for maximum power per PSU group of outlets connected to a respective power convertor, the maximum power per power supply line and / or the maximum power for the aircraft. Each outlet may know its outlet identifier / number, its power converter number, and the power supply line from which it is powered. This information may be pre-installed into a memory of, or associated with, each outlet. To ensure that during use the capacity of each power convertor and each column (and ultimately the allocated aircraft supply) is not exceeded, or is reduced if exceeded, the power delivered by one, some or all outlets is managed, with the individual outputs being reduced as more and more outlets come into use. According to a third aspect of the invention there is provided a method of managing power supplied to a plurality of passenger power outlets. Any of the above aspects of the invention may comprise, either singularly in combination, one or more features disclosed above, in the description and / or shown in the drawings. This disclosure includes that any features disclosed herein can be used to supplement any of the above aspects, and for such purpose none of those features, individually, is inextricably linked to any other such feature, notwithstanding that multiple features may be disclosed in the context of a particular embodiment in relation to other features. Brief Description of the drawings Various embodiments of the invention will now be described by way of example only in which: Figure 1 is a schematic representation of an aircraft power supply network, Figure 2 is a representation of a decision tree which is used by each outlet which implements power regulation of a system of power outlets. Figure 3 is a schematic representation of a second aircraft power supply network in a further embodiment, and Figure 4 is a schematic representation of a third aircraft power supply network in yet a further embodiment. Detailed Description There is now described a novel system, a novel system architecture, and novel power outlets which are part of said system and said architecture. The disclosed embodiments relate to the innovative management of an aircraft power supply for use by multiple power outlets, which allow passengers to charge / power their personal electronic devices, PEDs. Power management is self-regulating based on an initial set-up / configuration, and ensures that the maximum (rated) capacity of each power convertor and each power line, and in turn that of the allocated aircraft electrical supply, is not exceeded. This ensures that the total power delivered by the multiple outlets is within the predetermined / preconfigured constraints of the overall system, and subparts thereof. Reference is made to Figure 1 which shows an aircraft power supply system, which includes multiple power outlets 01, 02, 03 etc.., which enable passengers to power or charge their PEDs when connected thereto. The system also comprises an aircraft electrical power supply (denoted "AIRCRAFT’) which generates an electrical power supply derived from the aircraft’s engines. A powerline or power column, referenced COL, connects the aircraft electrical power supply to one or more power supply units, each referenced PSU. Each PSU comprises an AC-DC converter, and / or otherwise conditions the power signal to be suitable for use by the power outlet. Connected to each PSU is one or more respective power outlets, which can be seen collectively as grouped to a PSU. Each power outlet may be a USB-type outlet. The power outlets are provided for each passenger seat, and may be incorporated into the respective seat, into a neighbouring seat, or into a neighbouring structure, such as a bulkhead. Each seat may have multiple power outlets provided. Bl, B2 etc are breakout units. In operation, the PSUs send power down electrical wiring and at each seat the respective breakout box allows that main power run to continue to the next seat as a daisy chain while breaking out a power tapping for the seat group. Each power outlet further comprises, or is connected to, a processor, a memory and a transceiver. It will be appreciated that these may be embodied as a single unit / module, such as an integrated circuit hardware, which is incorporated into the outlet. The processor is arranged to update and evaluate a table (which may be termed a power distribution table) comprising instantaneous power delivery values for all outlets, and execute one or more decision trees using the power data. The decision tree includes steps to implement power distribution / sharing rules. An outcome of this processing may be for the processor to bring about a reduction in power delivered by one or more of the outlets. The memory is configured to store the power distribution table, the rule-implementing decision tree(s), together with any relevant characteristics (such as system values, parameters etc), which are required for regulating the distribution of power. The transceiver of each outlet is arranged to emit power status update signals (as radio frequency chirps) to other outlets which are indicative of a change in the power delivered by the outlet (including a power delivered by the outlet at that time). The transceiver is also arranged to receive such signals from other outlets, and cause the processor to execute the decision tree steps (to determine if the power currently delivered by the outlet should be reduced) The system is designed to support an amount of power that can be simultaneously and continuously delivered to all outlets within the system, with additional power delivery being available if not all outlets are in use or some are operating below a or the normal power delivery level. As disclosed above, the example systems herein described may be configured to include certain power allocation rules / criteria, accordingly to which power delivery levels can be delivered across the outlets. Such rules may for example include: • A maximum power that all passengers can use at the same time • A maximum power that each outlet can provide, if available system power permits. • For certain cabin classes (such premium classes), a higher average power may be available (at the expense power available of other cabin classes). These rules / values are stored in the memories of each of the outlets. The following values / parameters are stored in the memory, of each outlet: Which PSU group it belongs to. Which outlet number of the group it is. PSU maximum power output. Aircraft maximum power capacity. Column number. Column power capacity. Priority (e.g. the extent to which the outlet can be prioritised for higher power allocations than other outlets). Maximum power output limit of the outlet (which may be one of several preset options, one of which is selectable during a set-up procedure). A data payload of a chirp which is emitted by a power outlet, may include the following elements: ID of the power column on which the outlet (or rather the outlet’s PSU) resides. Outlet ID ID PSU Group ID Priority value of outlet, indicative of an outlet’s priority when considering to maintain power or reduce the same Current output power level of the outlet. Remaining Hops, namelyhow many more times the message is allowed to be relayed from one outlet to others, and decrements each time the message is re-transmitted. Time that power has been supplied for, which canbe used to help make decisions when power sharing. When an outlet receives a chirp it is able to reconstruct the unique identity of the outlet that initiated it using the combination of PSU group identifier and outlet number. Different sizes of power supplies may be suitable categorised. From this information each outlet writes the information from the received chirp into the power distribution table at the row number corresponding to the unique identity of the outlet that initiated the chirp. The table has data columns which correspond to those shown in Figure 3. Each of the outlets repeatedly evaluates their entire power distribution table summing data to establish the total power being consumed by the outlets of its PSU group (by adding together all entries where the PSU group matches its own), the total power being consumed by all units of its column group (by adding together all rows where the column number matches its own) and the total power being consumed globally by adding together all the rows / entries of the table. When a PED is plugged into an outlet, the outlet, as a default response, begins to provide a minimum predetermined power level for the device to establish what the outlet is and ask for what it wants under the USB PD scheme. Possibly subject to some configuration settings (where outlets of a certain priority or in certain locations, such as cabin class), may have a permanent maximum power limit (for example, economy class seats are never more than a certain maximum power) when the device has requested its power level the outlet chirps to update other outlets that it has allocated the power but it will only actually output that power level if there is adequate power available in the system. Otherwise, it will wait until the power becomes available and supply as much as much power as is available in the power budget from the current table data. At this time the update message from the outlet will propagate through the system and all outlets will accordingly update their power distribution tables with this new knowledge. All outlets continually evaluate their power distribution data and using the same ask the following questions of themselves in terms of power load: 1) Is the PSU I’m powered from OK? 2) Is the column my PSU is on OK? 3) Is the total aircraft load OK? If the answer is ‘YES’ to all three of the above questions then no action is required, but when an outlet chirps and notifies of an increase in its power level to the other outlets such that at least one of those answers becomes ‘NO’, those other outlets then work through decision tree shown in Figure 2 to adjust their power outputs until the new power allocation fits within all the power budgets (i.e. when the answer to all of questions 1), 2) and 3) is ‘YES’). For each question, the stored power distribution table is referred to, a respective power delivery value calculated and then compared with a stored maximum power delivery, one for each of the outlets of the overall system, the PSU connected to the outlet, and the power supply line which is connected to the PSU. These maximum power values may be termed power budgets. In order for each of the questions to be answered ‘YES’, an instantaneous power delivery value must be below the respective power budget. Figure shows a decision tree, which implements each of 1), 2) and 3). The decision tree includes a block of decision steps, which are applied should any of 1), 2) or 3) be answered in the negative. The block includes a series of decision steps, each being a yes / no question. In the block, a first decision step is whether the outlet is operating at greater than a predetermined power value. If power is maintained at the present level, there then follows a decision step relating to the (power) priority assigned to the outlet, and whether according to the power management rules this entitles the outlet to maintain its power, or necessitates a reduction in power . If the decision is that the priority of the outlet allows the outlet to maintain its power level, further included is a decision step which relates to how long a high priority outlet has been operating at a power level. All of the decision steps relate to an action which is either a reduction of power delivered by the outlet or maintenance of the existing power level. As all outlets are working with identically constructed tables, they will all arrive at the same conclusion and a single outlet will reduce power if needed, according to any particular rules applicable to that outlet, such as a designated priority level. As soon as an outlet changes power it then chirps with its new power level (and with the ‘time at power’ register reset to zero for the new level) and all outlets update their tables and continue to constantly ask the same questions 1), 2) and 3). If all the power budgets are met then the system settles, if not then the process continues until it does, at which point if the outlet that just had a PED plugged into it had to defer its full power output, it can now provide it to the device, even though it initially told all other units it had done so in order to cause the power shuffling to make it fit. A further system embodiment is shown in Figure 3, in which there are three PSUs, to each of which one power outlet is provided. Although in the above embodiments, the systems control power in a self-regulating manner (to meet predetermined power budgets), Figure 4 shows a further system embodiment in which an MCU, master control unit, is used to distribute and protect power to the power columns on which the PSUs reside. The embodiment also includes a CMS, central management system (which provides for at least some extent of centralised control in regulating power delivery across the outlets).

Claims

1. An electrical power outlet for a passenger aircraft, the outlet comprising:a connector for connection to a personal electronic device, PED;a transceiver to output power status update signals to other outlets, and to receive power status update signals from other outlets;a processor, which is configured to manage power delivered by the outlet using at least the power status update signals received from one or more other outlets.

2. An outlet as claimed in claim 1 in which the processor is configured to determine an instantaneous power consumption value of some or all of other outlets in a system / network of power outlets.

3. An outlet as claimed in claim 1 or claim 2 in which the processor is configured to determine a value of total power being consumed by one or more of the following: the or all outlets which share a common power converter, the total power being consumed by all outlets which receive power from a respective power supply line, and the total power being consumed globally by all outlets in the system / network.

4. An outlet as claimed in any preceding claim in which the processor configured to compare a calculated power consumption value to a predetermined maximum permissible power value of at least one of: the aircraft power supply; a power supply line; a power convertor; the outlet.

5. An outlet as claimed in any preceding claim in which the processor is configured to control power delivered by the outlet, the control including decrease of power delivered and maintenance of power delivered.

6. An outlet as claimed in any preceding claim in which the memory arranged to store power management rules, which when applied, determine whether modification of power delivered (to a PED) by the outlet is required.

7. An outlet as claimed in claim 6, in which the rules include the use of one or more of the following values: a maximum power capacity of the overall aircraft power supply,a maximum power capacity of a power supply line, a maximum power capacity of a power convertor, and a maximum power deliverable by the outlet.

8. An outlet as claimed in any preceding claim in which the processor is arranged to store in the memory power values contained in received power status update signals from other outlets in the system, and which relate to power delivered by each of those other outlets.

9. An outlet as claimed in claim 8 in which the processor is configured to continually determine an instantaneous cumulative value of power consumption for all and / or subsets of power values of outlets of stored in the memory.

10. An outlet as claimed in any preceding claim in which the power status update signals are indicative of characteristics of power supplied by the originating outlet.

11. An outlet as claimed in any preceding claim in which each of the status update signals include a respective value of power delivered by the outlets.

12. An outlet as claimed in any preceding claim in which the transceiver is arranged to emit a power status update signal when there is a change of power supply status at the outlet and / or at predetermined time intervals (in the absence of any such change).

13. An outlet as claimed in any preceding claim in which the transceiver is arranged to power status update signals over an air interface.

14. A system of power outlets for a passenger aircraft, comprising:a plurality of power outlets for connection to PEDs;a power supply line for connection to an aircraft electrical supply;one or more power converters connected to the power supply line;the power outlets connected to the at least one power converter, wherein the power outlets are outlets as claimed in any of claims 1 to 131.

15. A system as claimed as claimed in claim 14, one or more of the power outlets is configured to deliver power within different power management rules as compared to other outlets.

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