GB2561904A

GB2561904A - Wellfare cabin control system

Info

Publication number: GB2561904A
Application number: GB1706829.7A
Authority: GB
Inventors: Mikolajczyk Piotr
Original assignee: Boss Cabins Ltd
Current assignee: Boss Cabins Ltd
Priority date: 2017-04-28
Filing date: 2017-04-28
Publication date: 2018-10-31
Anticipated expiration: 2037-04-28
Also published as: GB201706829D0; GB2561904B

Abstract

A welfare cabin control system (10) comprises a generator set (12), a plurality of user-activatable electrical appliances (16,18,20,22,24,26) individually connectable to the generator set and a controller (14) controlling the selective connection of each individual electrical appliance to the generator set (12) to draw power concurrently from the generator set when activated by a user. The controller (14) actively monitors the summation of the power requirement of the plurality of electrical appliances concurrently activated. In the event that the power requirement is greater than a power output threshold of the generator set (12), the controller (14) denies power supply to at least one of the appliances (i.e. sheds loads) according to a predetermined appliance hierarchy. The invention may enable the generator set (12) to have a lower maximum power threshold, which may prevent or reduce low-loading of the generator set.

Description

(54) Title ofthe Invention: Wellfare cabin control system Abstract Title: Welfare cabin with load shedding (57) A welfare cabin control system (10) comprises a generator set (12), a plurality of user-activatable electrical appliances (16,18,20,22,24,26) individually connectable to the generator set and a controller (14) controlling the selective connection of each individual electrical appliance to the generator set (12) to draw power concurrently from the generator set when activated by a user. The controller (14) actively monitors the summation of the power requirement of the plurality of electrical appliances concurrently activated. In the event that the power requirement is greater than a power output threshold of the generator set (12), the controller (14) denies power supply to at least one ofthe appliances (i.e. sheds loads) according to a predetermined appliance hierarchy. The invention may enable the generator set (12) to have a lower maximum power threshold, which may prevent or reduce low-loading of the generator set.

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Title - Welfare Cabin Control System

The present invention relates to a welfare cabin electrical generation and control systems.

Welfare cabins are enclosures for crew working on-site, for example in a remote location, which provide facilities that can be used for warmth, water, shelter, cooking, sleeping, and the like.

Traditionally welfare cabins are supplied with an integral generator set, i.e. a diesel engine generator, to supply off-grid power to electrical appliances within the cabin. These electrical appliances include air heaters, water heaters, kettle, microwave, lights, auxiliary power sockets etc. It is a typical requirement of conventional generator sets that they are sufficiently powerful to run all of the internal appliances of the welfare cabin simultaneously. The downside of this is that running all the appliances simultaneously does not occur frequently, or for long periods, so the diesel engine of the generator set can be run close to idle for a significant portion of its operation.

This type of operation represents an inefficient use of the engine, thereby incurring unwanted fuel consumption and increasing engine wear.

If diesel engines are run at either low speeds or low loads, for example when a generator set is left idling as a so-called “standby” generator, or when a low load is applied to a higher-capacity generator set, then incomplete combustion of the fuel can occur, leading to carbon fouling or ‘coking’ issues. Incomplete combustion of the fuel leads to carbon formation in the engine, which is detrimental to engine efficiency and which in turn damages engine components, such as injectors, piston rings, as well as the seals that the piston rings form.

As well as carbon build-up itself, coking can cause further resulting problems with engine operation. For example, as a result of the decreased sealing capacity caused by coking damage, hot combustion gases can reach, and thereby ignite, oil in the system (often indicated by the engine producing blue smoke), which reduces the amount of oil present for lubrication purposes. In addition, incomplete combustion of the fuel may cause the formation of acids in the engine oil, which may cause further damage to the engine components over time.

Such issues, amongst others, increase the likelihood of engine faults and require the engine to be serviced on a regular basis, which thereby increases the maintenance costs associated with welfare cabins. Such costs can contribute to a significant proportion of the overall costs of operating a welfare cabin.

It is an aim of the invention to provide an improved welfare cabin electrical generation/supply system.

There has now been devised a welfare cabin control system, a method of controlling electrical power supplied to first and second electrical loads of a welfare cabin by a generator set, and a data carrier comprising machine readable instructions for operation of a controller of a welfare cabin control system, which overcome or substantially mitigate the aforementioned and/or other disadvantages associated with the prior art.

According to a first aspect of the present invention there is provided a welfare cabin control system comprising a generator set, a plurality of user-activatable electrical appliances individually connectable to the generator set and a controller controlling the selective connection of each individual electrical appliance to the generator set to draw power concurrently from the generator set when activated by a user, wherein the controller actively monitors the summation of the power requirement of the plurality of electrical appliances concurrently activated and in the event that said power requirement is greater than a power output threshold of the generator set, said controller denies power supply to at least one of said appliances according to a predetermined appliance hierarchy.

The plurality of appliances may comprise three, four, five, six or more appliances. The plurality of appliances may comprise a predetermined number of devices hard wired to the welfare cabin control system. The plurality of appliances may comprise a predetermined number of appliances, which may for example be less than twenty, fifteen, twelve or ten appliances.

The invention may permit more-efficient fuel consumption by the generator set, e.g. over prolonged use.

The invention may enable the generator set used to have a lower maximum power threshold, as the generator set does not need to cope with the combined total electrical power demand for concurrent use of all electrical appliances of the welfare cabin due to the ability to selectively supply only a subset of those appliances. The maximum power threshold of the generator set may be less than the summation of the power requirements for all the electrical appliances of the control system. The maximum power threshold of the generator set may be less than or equal to the summation of the power requirements of all-but-one, all-buttwo, all-but-three, or fewer of the electrical appliances of the control system.

The use of a generator set having a lower maximum power threshold may be advantageous as this may prevent or reduce low-loading of the generator set. The welfare cabin control system according to the first aspect of the present invention may therefore result in lower levels of carbon build-up or associated problems in the generator set, which may increase servicing intervals, improve fuel consumption, and/or lead to decreased running costs. A smaller, more costefficient engine capacity may be used.

The controller may be configured to selectively control the electrical power supplied by the generator set to the appliances based on a prioritisation algorithm, for example a pre-programmed prioritisation algorithm. The prioritisation algorithm may determine which of the electrical appliances is supplied with electrical power when the total electrical power required for concurrent use of the activated appliances exceeds a maximum electrical power output threshold of the generator set.

The appliance hierarchy and/or prioritisation algorithm may be determined at least in part by the electrical power consumption of the electrical appliances, e.g. a current/instantaneous, maximum or average power consumption value. For example, where a first appliance has a higher electrical power consumption value than one or more further electrical appliance, the controller may be configured to prioritise supply electrical power to the first appliance where the total electrical power required for concurrent use of the plurality of activated appliances exceeds the electrical power threshold of the generator set, or vice versa.

The prioritisation algorithm or hierarchy may be chosen by a user, or may, for example, be pre-programmed by a manufacturer. The prioritisation algorithm may be alterable by a user, thereby enabling a user to set a preference for which of the electrical appliances is supplied with power when the total electrical power required exceeds of the threshold for the generator set.

Each of the plurality of electrical appliances or appliance types may be labelled as higher priority or lower priority relative to the other electrical appliance(s) or appliance type(s) dependent on its respective position within the hierarchy.

Upon activation of a higher priority appliance by a user, the controller may be configured to switch or restore the supply of electrical power from an activated lower priority appliance to the higher priority appliance. The controller may switch supply of electrical power from a higher priority appliance to an activated lower priority appliance, for example after a pre-determined time period of use of the higher priority appliance has elapsed, or when the operation of the higher priority appliance has ceased.

The controller may comprise a control circuit and one or more switches under control of the control circuit. A plurality of electrical switches may be provided for selectively connecting/disconnecting each appliance to the generator set by the control circuit. The control circuit may comprise a programmable computer chip or other electronic device or data processor.

The controller may be arranged to deny power supply to one or more activated appliances until the power output threshold is met. The controller may be arranged to deny power supply to the lowest priority appliance of the activated appliances in the hierarchy upon determining that the concurrent power requirement is greater than the power output threshold. The controller may iteratively deny power to the next lowest priority appliance of the activated appliances until the power output threshold is met.

The controller may be configured to output a signal indicating when an activated appliance is denied power. The controller may be configured to output a signal indicative of which of the activated electrical appliances is being currently supplied and/or denied electrical power from the generator. The signal may, for example, comprise any or any combination of an electrical/data signal, an audio signal, and/or a visual signal. The welfare cabin control system may comprise a display for displaying which of the electrical appliances is activated and/or being supplied with electrical power in use. This may be beneficial as it may indicate to a user which of the electrical loads is being denied power by the system, e.g. as opposed to being due to an electrical fault in the appliance. Additionally or alternatively, an audio or data/message output system may be used. Each appliance may have associated therewith an audio or data signal, which may be output by the controller when said appliance is denied power by the controller.

The electrical appliances may comprise any or any combination of the following: one or more water heater; one or more cooking appliance; one or more power socket, eg a 13A power socket; one or more air heater; or an energy store, eg a battery/capacitor and/or associated charging system. Any of said appliances may be designated as appliance types. A plurality of the same or different appliances may be assigned to a common appliance type.

The electrical appliances may comprise a kettle, a flowing hot water heater and/or a fan heater.

The system may comprise one or more light or lighting circuit. The light(s) may or may not comprise one of the appliances under the control of the controller. The light(s) may be connected to the generator set via an electrical energy store. The light(s) may be powered by the energy store, e.g. only by the energy store. The energy store may comprise one of the appliances under the control of the controller.

The light(s) may have a different/lower power rating to the (other) electrical appliances.

The electrical power threshold of the generator set may comprise an electrical power which is greater than or equal to the maximum electrical power consumption of any one, or two of the plurality of electrical appliances. The electrical power threshold of the generator set may comprise at least 1 kW, at least 2kW, or at least 3kW. The electrical power threshold of the generator set may comprise at most 3kW, at most 4kW, at most 5kW, at most 6kW, at most 7kW, at most 8kW, at most 9kW, or at most 10kW.

The controller may be configured to automatically begin operation of the generator set when an appliance is activated or else when a minimum power requirement threshold or minimum generator output threshold is met.

The controller may be configured to automatically cease operation of the generator set where no electrical loads are in use or else when the power requirement of the activated appliance(s) fails to meet a minimum power threshold.

The system may comprise an energy store. The controller may or may not monitor the charge level of the energy store. The controller may control selective charging of the energy store by the generator set. The controller may control selective discharging from the energy store to one or more active appliance. The controller may or may not control selective disconnection of the energy store from the generator set, e.g. by denial of power supply in a manner akin to an appliance.

The controller may meet some or all of the power requirement of the activated device(s) from the energy store in addition to, or instead of, via the generator set.

Lighting for the welfare cabin may be powered from the energy store.

The controller may selectively charge the energy store, e.g. in combination with supplying power to one or more other activated appliance. The controller may selective charge the energy store to ensure a minimum power output threshold or desired operating point of the generator set is met.

The engine of the generator set may be operated at a desired operating point, e.g. in a substantially steady state, or else within a predetermined range of variation of said desired operating point. Variation in engine operation over its full operational range may be inhibited or restricted. The engine may be operated only at a fixed operating point or range, e.g. as defined by a torque output, throttle or rotational speed setting.

The controller may monitor the summation of power requirements of activated appliances, i.e. prior to altering a current/existing appliance power supply. The controller may immediately deny supply of power to an activated appliance, e.g. a newly activated appliance, if the summation exceeds the power threshold.

The prioritisation algorithm may determine which or which combination/subset of the electrical appliances is supplied with power when the total electrical power requirement of the activated electrical appliances exceeds the electrical power threshold of the generator set.

The prioritisation algorithm and/or hierarchy may be alterable by a user, thereby enabling a user to set a preference for which of the electrical appliances or appliance types is supplied with power when the total electrical power requirement exceeds the electrical power threshold.

The hierarchy may comprise a ranking from 1 to n (where n is the number of electrical appliances connected to the generator set).

Any or any combination of the electrical appliances may have associated therewith a predetermined or pre-set duration of operation. The predetermined duration of operation may comprise a known maximum duration of an instance of operation of the appliance. The pre-set duration may comprise a duration of a current instance of activation set by a user.

The controller may maintain a log of appliance identification, hierarchy rating and/or power requirement for each appliance of the system. The controller may maintain a log of predetermined and/or historical duration of operation, e.g. an instance of operation, for each appliance of the system.

Where the terms ‘lower ranked’ electrical appliance or ‘higher ranked’ electrical appliance are used, it will be appreciated that those terms may comprise a combination of lower ranked appliances or a combination of higher ranked appliances respectively.

The generator set may comprise a combustion engine and an electrical generator driven by the combustion engine. The generator set may comprise a diesel generator set.

Each appliance may be connected to the controller and/or generator on a wiring circuit. Each appliance, or collection of appliances, may be provided on its own circuit.

The system may further comprise a selective disconnection device for each appliance/circuit. The system may comprise a conventional circuit breaker device, e.g. a fuse box or trip switch device, which may be used in conjunction with or in addition to the controller and its associated switches.

According to a further aspect of the present invention there is provided a method of controlling electrical power supply in a welfare cabin comprising a generator set, a plurality of user-activatable electrical appliances individually connectable to the generator set and a controller controlling the selective connection of each individual electrical appliance to the generator set to draw power concurrently from the generator set when activated by a user, wherein the method comprises actively monitoring the summation of the power requirement of the plurality of electrical appliances concurrently activated and in the event that said concurrent power requirement is greater than a power output threshold of the generator set, denying power supply to at least one of said appliances according to a predetermined appliance hierarchy.

The method may comprise automatically beginning operation of the generator set where it is desired to utilise an electrical appliance, and/or may comprise automatically ceasing operation of the generator set where no electrical appliances are in use.

According to a further aspect of the present invention there is provided a data carrier comprising machine readable instructions for operation of a controller of a welfare cabin control system, the welfare cabin control system comprising a generator set and a plurality of user-activatable electrical appliances individually connectable to the generator, wherein the machine readable instructions cause the controller to: control the selective connection of each individual electrical appliance to the generator set to draw power concurrently from the generator set when activated by a user; actively monitor the summation of the power requirement of the plurality of electrical appliances concurrently activated; and, in the event that said concurrent power requirement is greater than a power output threshold of the generator set, deny power supply to at least one of said appliances according to a predetermined appliance hierarchy.

It will be appreciated that any optional features of any one aspect of the present invention may be equally applied to any other aspect of the present invention.

Practicable embodiments of the invention are described in further detail below with reference to the accompanying drawings, of which:

Figure 1 is a schematic block diagram illustrating a welfare cabin control system according to the first aspect of the present invention; and

Figure 2 is a schematic top plan view of a welfare cabin incorporating the welfare cabin control system of Figure 1; and

Figure 3 shows a test setup for a welfare cabin control system according to an example of the invention.

A welfare cabin control system according to the first aspect of the present invention, generally designated 10, is shown schematically in Figure 1. The welfare cabin control system 10 comprises a generator set 12 (e.g. an AC generator set), a controller 14, a kettle 16, a hot water heater 18, a microwave 20, a power socket 22, an electric air heater 24, and a battery charger 26. Also shown are an energy store in the form of battery bank 28 connected to the battery charger 26, and a secondary power system 30 connected to the battery bank 28.

The appliances 16-26 connected to the generator set may represent a 240V electrical system, e.g. akin to a mains power system. Different voltage systems may be used to reflect mains supply in different countries. The power socket 22 is a 13 Amp socket of conventional type in this example.

The generator set 12 is a conventional diesel generator set, and in presently preferred embodiments may comprise a diesel engine having an output shaft which drives a rotor of an electrical generator. The electrical generator and motor are typically co-located and/or mounted to a common support structure, such as a chassis/frame.

Where electrical power is supplied to the battery charger 26, electrical power may be stored in the battery bank 28. A charge on the battery may be used to power the system, in addition to, or instead of, the generator set 12. Thus the secondary power system 30 and/or appliances 16-24 can be potentially used for a limited period of time via the battery(s) 28 when the generator set 12 is not in operation or fails, or else when the generator set output is insufficient to meet the demands of the devices drawing power from the system.

The secondary power system 30 is a DC system in this example. The battery bank 28 is a 12V battery bank and a corresponding 12V power supply is thus used for system 30 and any devices connected thereto.

The controller 14 comprises a microprocessor, such as a programmable circuit board or programmable logic device. The controller 14 in presently preferred embodiments is pre-programmed with a prioritisation algorithm which dictates a preferential supply of power to the kettle 16, the hot water heater 18, the microwave 20, the 13A power socket 22, the electric air heater 24, and the battery charger 26.

In present embodiments, lighting for the welfare cabin is powered by the secondary power system 30. Thus the lighting needs for the welfare cabin can be met via the energy store rather than directly via the generator set 12. The lighting system can thus be powered by charging the battery bank 28 under the control of the controller 14. The lighting may or may not require separate dedicated control.

In other embodiments, the lighting could be controlled by the controller 114 in a manner akin to other appliances 16-28. Also, other appliances (e.g. low power appliances) could be supplied power via the secondary power system 30 in different embodiments, rather than directly via the AC system of the generator set 14.

In one embodiment, electrical power is selectively supplied to the following electrical loads in order of preference: kettle 16; hot water heater 18; microwave 20; 13A power socket 22; electric air heater 24; battery charger 26.

Each electrical load/appliance may thus be given a ranking of 1-n, where ‘ri is the number of electrical appliances connected to the welfare cabin control system.

In other examples, electrical appliances may be designated appliance types and rankings may be provided for each electrical appliance type. Thus different appliances of a common type could have a common ranking. In such an example, rankings of 1-n may be provided, where ‘n’ is the number of appliance types. Two or more appliances of a common type may be treated as having equal priority.

Additionally or alternatively, banding of rankings for different appliance types could be provided, such that individual appliances of a common type could still be ordered (e.g. if a priority order within appliance types is required to be determined during operation). For example, a ranking may comprise an alphanumeric code indicating both appliance type and ranking within that type. A code having a prefix for the appliance type and a suffix for the ranking within that type could be used as one example, e.g. A1-An, B1-Bn, C1-Cn ..., etc. However other code and/or ranking systems may be devised to this end.

Using any or any combination of the above techniques, each appliance has a ranking that can be used to determine which appliance(s) should be powered in the event that it is not possible to supply instantaneous power to meet all the electrical loads on the system.

If appliance types are used, the following types are proposed:

- water heating

- cooking

- power sockets for user appliances (ancillary devices)

- air/space heating

- electrical energy storage /charging

This order may be used as the order of ranking or priority for controlling the supply of power in use, e.g. with water heating ranked highest. In various embodiments of the invention, charging of the energy store may rank lowest, or below water, cooking or space heating requirements, e.g. due to the lower power requirement of energy store charging. However different welfare cabin scenarios may require a different order to be prescribed or user control to configure a desired ranking of appliance types or individual appliances.

The welfare cabin control system may supply any or any combination of the aforementioned electrical loads 16,18,20,22,24,26 with power provided that the maximum power threshold of the generator set 12 is not reached. Where the maximum power threshold of the generator set 12 is reached, the controller 14 will operate to remove supply of electrical power to one or more of the electrical loadsl 6,18,20,22,24,26 until the electrical power in use by the electrical loads

16,18,20,22,24,26 is lower than the maximum power threshold of the generator set 12.

For example, a generator set 12 may have a maximum power threshold of 3kW. A user may enter the welfare cabin, and turn on the hot water heater 18, which has a power rating of 3kW. If the user attempts to turn on the kettle 16, which has a power rating of 2kW, whilst the hot water heater 18 is in use, then the controller will operate to remove the supply of electrical power to the hot water heater 18, and to supply electrical power to the kettle 16, based on the prioritisation algorithm programmed into the controller 14, since the combined power rating of the kettle 16 and the hot water heater 18 is greater than the maximum power threshold of the generator set 12 (5kW>3kW). Once the kettle 16 has boiled, the kettle 16 will turn off, and the controller 14 will operate to restore supply of electrical power to the hot water heater 18.

Operation of the welfare cabin control system 10 in such a manner means that the power threshold of the generator set 12 only has to be large enough to enable operation of the electrical load 16,18,20,22,24,26 having the largest maximum power rating, as concurrent operation of any combination of electrical loads

16,18,20,22,24,26 resulting in a total power rating greater than the maximum power threshold of the generator set 12 will result in operation of the controller 14 to selectively remove and/or switch supply of power to the electrical loads

16,18,20,22,24,26 until the total power rating of the electrical loads

16,18,20,22,24,26 in concurrent use is lower than the maximum power threshold of the generator set 12.

However the power threshold of the generator set 12 may be larger than that of the single largest electrical load connected to the system, e.g. to be able to accommodate two or more concurrent appliances at once. The maximum power threshold of the generator will be lower than the total power requirement of all electrical loads used concurrently.

The exact maximum power threshold of the generator set relative to the total/collective power requirement of all electrical loads on the system may be selected so as to ensure that the motor is normally operating at a non-idle throttle/rpm setting when in use. This may be determined by analysing normal usage and peaks and troughs in power usage in welfare cabins and selecting a generator set for which a desirable operational range of the motor (i.e. an operational range between idle and a maximum throttle/rpm setting for the engine) at which the engine can operate for prolonged periods without substantial issues arising due to incomplete combustion or coking.

In the present example, instead of defining a desirable range of engine operation, the engine/generator set is controlled to operate at a fixed operating point. In a specific example, the engine will run at 3000 rpm. Whether a fixed operating point or defined sub-range of the available engine operating range is defined, the operation is closer to a steady-state and/or optimal efficiency point for the engine. This can carry significant efficiency and/or other practical benefits for the engine.

In some examples, the controller may not have a minimum power threshold, e.g. such that the generator set engine is always started when an electrical load is applied to the system.

In other examples, a minimum power threshold may be used to ensure that the generator set is not used for prolonged periods of time below the minimum power threshold. For example the controller may inhibit operation of the generator set when the electrical load on the system is below the minimum threshold and/or may initiate electrical supply to one or more additional appliances (e.g. in addition to that selected by the user) to ensure that the minimum power threshold is achieved. In this regard, the controller may select to supply power to the battery charger 26 at a rate sufficient to meet the minimum power threshold.

When a user attempts to switch one or more appliance that does not meet the minimum threshold and the appliance(s) could be powered by the battery 28 alone, the controller may avoid starting up the generator set and may meet the demand using the battery only. Such low-level appliances could comprise lighting and/or user devices connected to socket(s) 22.

In any examples of the invention, the battery or other electrical energy store 28 may comprise one or more sensor indicating the current level of charge and/or available capacity for energy storage. The sensor output is communicated to the controller such that it can be accommodated in power supply decisions made by the controller.

When one or more appliance is activated by the user having an electrical load that does not meet the minimum power threshold, or the fixed generator operating point, the controller may control simultaneous charging of the energy store 28, e.g. in order to make up any deficit.

If the generator set is activated to meet only a battery charging demand of energy store 28 (i.e. indicative of the smallest electrical load on the system), the lighting and/or any other appliances on the secondary power supply system/circuit 30 could be on a timer or other usage sensor in order to avoid unnecessary time for which the power supply system 10 is operating at lower efficiency.

Figure 2 shows a layout of a welfare cabin 32 incorporating the present invention.

It can be seen that the generator set 12 will typically be located in a compartment of the welfare cabin 32, which is separate from one or more living spaces. The welfare cabin may comprise one or two or more partitioned living spaces as well as a water closet. Partitioned office and living quarters are shown in this example. The living space(s) and/or water closet will typically have an external door and/or window.

Further details will not be described since the configuration of different welfare cabins may be accommodated using the present invention. However it is intended that the welfare will provide a temporary or semi-permanent structure which does not require an external power source. Separate internal living spaces may each have one or more

The above description provides an overview of examples of the invention. Further details are discussed below in relation to Figure 3, which shows an example of a practical test system in which the different elements of an operational system are provided on a common support structure (i.e. wall 34) for testing. The generator set 12 itself is not shown in Figure 3.

Each of the appliances 16-26 are connected to the control box 36 (i.e. containing the controller 14 discussed above. In addition, it can be seen that each individual appliance, or plurality appliances having a common appliance type, is connected to the control box 36 via its own connection/circuit. The control box comprises a bank of switches 38 under the control of the controller 14 and each electrical connection/circuit and be selectively connected or disconnected to the power supply from the generator.

A plurality of individual lights 40 of the lighting circuit described above are also shown as being connected to the energy store 28, e.g. on individual or a plurality of lighting circuits. One or more light enclosures may be connected on the/each lighting circuit.

Also shown is a conventional circuit passive breaker device 42, e.g. a fuse box or bank of trip switches for each circuit of the primary electrical system. Thus faults, such as short circuits or the like, in appliances or the generator can cause appliance circuits to be individually or collectively isolated/disconnected in a conventional manner. Thus the active control of the present invention can work in conjunction with a more conventional, passive circuit breaker device. .

Also, each appliance has a user control, e.g. a further switch at the appliance itself, for user activation of each individual device. Thus when an user switches on a device using the user control for the appliance, the controller can monitor the electrical load on the system and decide whether or not to deny power supply to any individual or collection of appliances.

Unlike a conventional fuse box, the controller of the present invention actively monitors the current loading on the generator/system caused by the summation of the appliance loads and selectively disconnects appliances where appropriate based on the predetermined ranking.

A basic implementation of the system may consider instantaneous power requirements only, i.e. such that controller reacts only to instantaneous power demands. However more sophisticated control algorithms may accommodate one or more known characteristic of each appliance. For example a non-volatile data store accessible to the controller may comprise not only an appliance identifier and ranking but also one or more characteristic for the appliance. The characteristic may comprise one or more of:

- a min, max or average duration of an instance of operation of an appliance;

- a power consumption profile for the appliance over time

- an average or fixed power consumption of an appliance

Using any or any combination of the above, the controller could balance instantaneous or short term demands with longer term demands, e.g. selecting to prioritise a known short term, high loading demand in the knowledge that a longer term demand (such as air heating) can be recommenced once the short term demand is completed.

Furthermore there are various ways the energy store 28 can be used in the control system to charge and discharge the energy store in a manner that promotes consistent usage of the combustion engine of the generator set within a desired operational range or at a fixed/steady-state setting..

In examples of the invention described herein a user information or signal output device 27 may be used as shown in Figure 1. The output device in this example comprises a display panel having an individual light (or other visual indicia) indicating the status of each appliance or circuit of the control system. The display may thus indicate when a device is selectively denied power by the controller. This may serve to indicate to a user when a device is actively denied power, rather than the appliance status being confused by the user as being indicative of a fault. The display panel may also indicate a power supply condition to the appliance/circuit by the controller such that users can appreciate the active/automated control of the system.

It has been found that power supply systems of the kind described herein can offer generator/energy efficiency savings compared to conventional generator-driven power supply systems. The term ‘Intelligent Load Management’ has been coined by the applicant as being indicative of a system of the type described herein.

Claims

Claims:

1. A welfare cabin electrical control system comprising: a generator set; a plurality of user-activatable electrical appliances individually connectable to the generator set; and, a controller controlling the selective connection of each individual electrical appliance to the generator set to draw power concurrently from the generator set when activated by a user, wherein the controller actively monitors the summation of the power requirement of the plurality of electrical appliances concurrently activated and in the event that said power requirement is greater than a power output threshold of the generator set, said controller denies power supply to at least one of said appliances according to a predetermined appliance hierarchy.

2. The control system of claim 1, wherein the plurality of appliances comprises a limited number of between five and twenty appliances.

3. The control system of claim 1 or 2, wherein the power output threshold of the generator set is a maximum power output threshold and is less than the summation of the concurrent power requirements for all the electrical appliances of the control system.

4. The control system of claim 1 or 2, wherein the power output threshold of the generator set is less than 7kW or 5kW.

5. The control system of any preceding claim, wherein the controller is configured to selectively deny the supply of electrical power to one or more of the activated appliances based on a predetermined prioritisation algorithm.

6. The control system of any preceding claim, wherein the appliance hierarchy is determined at least in part by an electrical power consumption value for each of the electrical appliances, wherein a higher electrical power consumption value has greater priority in the hierarchy than a lower power consumption value.

7. The control system of any preceding claim, wherein upon activation of a higher priority appliance by a user, the controller is configured to switch the supply of electrical power from an activated lower priority appliance in the hierarchy to the higher priority appliance.

8. The control system of any preceding claim, wherein the controller comprises a control circuit and a plurality of switches under control of the control circuit, the plurality of switches arranged for selectively connecting/disconnecting each appliance to the generator set by the control circuit.

9. The control system of any preceding claim, wherein the controller is arranged to deny power supply successively to a plurality of activated appliances in an order according to the hierarchy until the power output threshold is met.

10. The control system of any preceding claim, comprising a user display and the controller is configured to output a signal indicating when an activated appliance is denied power on the display.

11. The control system of any preceding claim, wherein the electrical appliances comprise any or any combination of: one or more water heater; one or more cooking appliance; one or more power socket; one or more air heater; an energy store; and/or an energy store charging system.

12. The control system of claim 11, wherein the water heater is highest priority in the hierarchy and/or the energy store charger is lowest in the priority.

13. The control system of claim 11 or 12, wherein the water hear and/or the cooking appliance rank higher in the hierarchy than the power socket and/or the air heater.

14. The control system of any one of claims 11 to 13, comprising one or more lighting circuit powered only by the energy store.

15. The control system of any preceding claim, wherein generator set, controller and appliances comprise a primary power supply system, at least one appliance comprising an energy store charging system, wherein an energy store connected to the charging system supplies power to a secondary power supply system.

16. The control system of claim 15, wherein the primary power system is a AC system and the secondary power supply system is a DC system.

17. The control system of any preceding claim, wherein the generator set is activated by the controller and a combustion engine of the generator set is controlled to operate in a restricted operational range and/or at a fixed operating point.

18. The control system of any preceding claim, wherein the hierarchy comprises a ranking from 1 to n, where n is the number of electrical appliances connected to the generator set.

19. The control system of any preceding claim, comprising a data store accessible to the controller, wherein the data store comprises a log of appliance identification, a hierarchy rating and a power requirement for each appliance of the system.

20. The control system of any preceding claim, wherein the generator set comprises a combustion engine and an electrical generator driven by the combustion engine.

21. The control system of any preceding claim, further comprising a circuit breaker device for selective disconnection of appliances from the generator set in the event of a fault.

22. A data carrier comprising machine readable instructions for operation of a controller of a welfare cabin control system, the welfare cabin control system comprising a generator set and a plurality of user-activatable electrical appliances individually connectable to the generator, wherein the machine readable instructions cause the controller to: control the selective connection of each individual electrical appliance to the generator set to draw power concurrently from

5 the generator set when activated by a user; actively monitor the summation of the power requirement of the plurality of electrical appliances concurrently activated; and, in the event that said concurrent power requirement is greater than a power output threshold of the generator set, deny power supply to at least one of said appliances according to a predetermined appliance hierarchy.

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