WO2013108046A1

WO2013108046A1 - Electrical supply controller

Info

Publication number: WO2013108046A1
Application number: PCT/GB2013/050123
Authority: WO
Inventors: Daniel LAWES; Simon WALTERS; Michael YEOMAN
Original assignee: South Downs Solar Limited
Priority date: 2012-01-20
Filing date: 2013-01-21
Publication date: 2013-07-25
Also published as: AU2013210888A1; GB2498558B; GB201200957D0; GB2498558A

Abstract

An electrical supply controller has a switch (9) for selectively coupling and decoupling an electrical supply (3) to a hot water immersion heater (11). A first current sensor (19) detects when an electric current delivered from a renewable source of electricity (2), such as a photovoltaic panel, exceeds a first threshold current. A first wireless transmitter (22) transmits a first signal in response to the electric current exceeding the first threshold current, and a wireless receiver (25) is arranged, in response to receiving the first signal, to cause the switch (9) to couple the electrical supply (3) to the output (10). A second current sensor (20) detects when an electric current delivered to an electrical device (15), such as a kettle, exceeds a second threshold current. A second wireless transmitter (23) transmits a second signal in response to the second current sensor (20) detecting the electrical current exceeding the second threshold current. In response to receiving the second signal, the wireless receiver(25) causes the switch (9) to decouple the electrical supply (3) from the hot water immersion heater (11).

Description

ELECTRICAL SUPPLY CONTROLLER

Field of the Disclosure The present disclosure relates to an electrical supply controller. It is particularly, but not exclusively, applicable to switching an electrical supply in response to variations in the current delivered from a renewable source of electricity.

Background to the Disclosure

Sources of electricity that use renewable energy tend to provide fluctuating amounts of electricity, dependent on variations in the natural resource from which the electricity is generated. For example, photovoltaic (PV) panels typically generate most electricity during the middle of the day when the sky is clear, less electricity early in the morning and late in the evening or when the sky is cloudy, and virtually no electricity at night.

An increasing number of buildings, whether homes, offices, public buildings, commercial buildings or industrial premises, have their own means of generating electricity from renewable energy. For example, PV panels are installed on roofs or wind turbines are installed in gardens or surrounding land. However, in most cases the renewable source of electricity is not sufficient by itself for supplying all the electricity required by the building, due in large part to the fluctuations in the amount of electricity provided. Buildings with their own renewable sources of electricity still therefore tend to be connected to an electricity grid for supplying electricity from power stations when needed. This allows the electricity generated by the renewable source to be

supplemented by electricity from the electricity grid when demand for electricity in the building exceeds the amount of electricity being provided by the renewable source. Thus, peaks in demand for electricity in the building can still be met.

So that the benefit of the renewable source of electricity can be maximised, the electricity grid is often also connected so as to collect electricity generated by the renewable source when it is not being used in the building. Companies providing electricity from the electricity grid have devised charging schemes to reflect this, with customers paying for electricity supplied to them from the electricity grid and receiving money for electricity collected from their building's renewable source by the electricity grid.

In order for customers to derive the optimum benefit from this arrangement, there is a need for the use of electricity with their building to be carefully controlled. For example, customers may try to ensure that electrical devices within the building that require large amounts of electricity use electricity provided by the renewable source as far as possible. Various systems for controlling when electrical devices within buildings are switched on and switching between using electricity from the renewable source and the electricity grid are available. However, these systems tend to be complex. Moreover, they typically require extensive wiring in to the electrical circuits within the building. This makes them expensive for the customer.

Summary of the Disclosure

According to a first aspect of the present disclosure, there is provided an electrical supply controller comprising:

a switch arranged to selectively couple and decouple an electrical supply to an output;

a first current sensor arranged to detect when an electric current delivered from a source of electricity to the electrical supply exceeds a first threshold current;

a first wireless transmitter arranged to transmit a first signal in response to the first current sensor detecting the electric current delivered by the source of electricity to the electrical supply exceeding the first threshold current; and

a wireless receiver arranged, in response to receiving the first signal, to cause the switch to couple the electrical supply to the output.

According to a second aspect of the present disclosure, there is provided a method of controlling an electrical supply using a switch arranged to selectively couple and decouple an electrical supply to an output, the method comprising:

detecting when an electric current delivered from a source of electricity to the electrical supply exceeds a first threshold current;

wirelessly transmitting a first signal in response to detecting the electric current delivered by the source of electricity to the electrical supply exceeding the first threshold current; and,

in response to wirelessly receiving the first signal, causing the switch to couple the electrical supply to the output.

Through the use of a wireless transmitter and a wireless receiver, the controller can be installed simply and cheaply.

The source of electricity may be arranged to generate electricity from renewable energy. It may be a renewable source of electricity. For example, the source of electricity may be photovoltaic, such as a photovoltaic panel or array. Alternatively, it may be a wind turbine. Usually, the electrical supply also receives electricity from an electricity grid. In other words, the electrical supply may be coupled to receive electricity from the electricity grid and from the (renewable) source of electricity.

The output is usually coupled to an electrical device that requires a relatively large amount of electricity in comparison to other electrical devices in the same electrical system. This might be 2 kW or more, for example. In one example, the output is coupled to, or is, a hot water immersion heater.

The switch and the wireless receiver may be integrated into a switching unit. The switching unit may be mountable in a back box of a household electrical circuit. This further simplifies installation.

The first current sensor may comprise a transducer inductively couplable to a conductor of the current delivered by the source of electricity to the electrical supply. Again, the use of a transducer can simplify installation and improve safety.

The first current sensor may have an interface that allows the first threshold current to be adjusted.

The electrical supply controller may further comprise:

a second current sensor arranged to detect when an electric current delivered to an electrical device from the electrical supply exceeds a second threshold current; and a second wireless transmitter arranged to transmit a second signal in response to the second current sensor detecting the electrical current delivered to the electrical device from the electrical supply exceeding the second threshold current,

wherein the wireless receiver is arranged, in response to receiving the second signal, to cause the switch to decouple the electrical supply from the output.

The electrical supply controller may further comprise:

a third current sensor arranged to detect when an electric current supplied to another electrical device from the electrical supply exceeds a third threshold current; and a third wireless transmitter arranged to transmit a third signal in response to the third current sensor detecting the electrical current supplied to the other electrical device from the electrical supply exceeding the third threshold current,

wherein the wireless receiver is arranged, in response to receiving the third signal, to cause the switch to decouple the electrical supply from the output.

The signal(s) may be at a frequency of approximately 433 MHz.

Preferred embodiments of the invention are described below, by way of example only, with reference to the accompany drawings. Brief Description of the Accompanying Drawings

Figure 1 is a schematic illustration of an electrical system incorporating an electrical supply controller according to a preferred embodiment.

Figure 2 is a schematic illustration of a first current sensor and first wireless transmitter of the electrical supply controller.

Figure 3 is a schematic illustration of a second current sensor and a second wireless transmitter of the electrical supply controller.

Figure 4 is a schematic illustration of a wireless receiver and a switch of the electrical supply controller.

Figure 5 is a flow chart showing operation of the electrical supply controller.

Detailed Description of the Preferred Embodiments Referring to Figure 1 , a building has an electrical system 1 including a renewable source of electricity 2 coupled to an electrical supply 3 via a first electrical circuit 4 to provide electricity to the electrical supply 3. An electricity grid 5 is also coupled to the electrical supply 3 via a second electrical circuit 6 to provide electricity to the electrical supply 3. Third and fourth electrical circuits 7, 8 are coupled to the electrical supply 3 to allow the supplied electricity to be distributed around the building.

In this embodiment, the renewable source of electricity 2 is a photovoltaic (PV) panel, including an inverter for converting direct current (DC) from the PV panel to alternating current (AC) compatible with the electricity grid 5, and the electrical supply 3 is a domestic fuse box or consumer unit. The renewable source of electricity 2 and the electricity grid 5 are coupled to a bus-bar of the electrical supply 3. The bus-bar is a conductor with sufficient capacity to carry the entire electrical load of the electrical supply 3. It couples the renewable source of electricity 2 and the electricity grid 5 to one another, so that they can deliver electricity via a common path, either to the electrical supply 3 or to elsewhere via the electricity grid 5.

The third electrical circuit 7 couples the electrical supply 3 to a first switch 9. The first switch 9 has an output 10 coupled to an immersion heater 11 of a domestic hot water tank 12. The fourth electrical circuit 8 couples the electrical supply 3 to first and second electrical sockets 13, 14. First and second electrical appliances 15, 16 are coupled to the fourth electrical circuit 8 via first and second electrical plugs 17, 18, which are respectively coupled to the first and second electrical sockets 13, 14. In this embodiment, the first electrical appliance 15 is a kettle and the second electrical appliance 16 is a microwave oven.

An electrical supply controller comprises first, second and third current sensors 19, 20, 21 , first, second and third wireless transmitters 22, 23, 24, a wireless receiver 25 and the first switch 9. The first current sensor 19 is arranged to detect electrical current in the first electrical circuit 4 and is coupled to the first wireless transmitter 22. The second current sensor 20 is positioned between the first electrical socket 13 and the first electrical plug 17 so as to be able to detect electrical current being delivered to the first electrical appliance 15, and is coupled to the second wireless transmitter 23. The third current sensor 21 is positioned between the second electrical socket 14 and the second electrical plug 18 so as to be able to detect electrical current being delivered to the second electrical appliance 16, and is coupled to the third wireless transmitter 23. The first, second and third wireless transmitters 22, 23 and 24 are arranged to communicate with the wireless receiver 25 using radio signals, and the wireless receiver 25 is coupled to the first switch 9.

Referring to Figure 2, the first current sensor 19 comprises a transducer 26 inductively coupleable to the first electrical circuit 4. The transducer 26 is a loop of one or more turns of a conducting material that fits around a wire 27 of the first electrical circuit 4. The first wireless transmitter 22, coupled to the first current sensor 19, has an antenna 28 for transmitting first and second signals, an interface 29 for setting a first threshold current and an indicator 30 for showing whether or not the first current sensor 19 and/or the first wireless transmitter 22 is/are operating.

When the transducer 26 is in position, electrical current passing along the wire 27 induces an electrical current in the loop. This electrical current induced in the loop is proportional to the electrical current passing along the wire 27. The current sensor 19 has a circuit for detecting the induced electrical current, and hence the electrical current in the wire 27. The first current sensor 19 is arranged to compare the electrical current detected in the wire 27 to the first threshold current. In more detail, the electrical current induced in the loop is converted to a voltage using a potentiometer, and this voltage is compared to a reference voltage determined by appropriate calibration. The first wireless transmitter 22 is arranged to transmit the first signal when the electrical current detected in the wire 27 passes above the first threshold current, and to transmit the second signal when the electrical current detected in the wire 27 passes below the first threshold current.

Referring to Figure 3, the second current sensor 20 and second wireless transmitter 23 are integrated into a single unit 31. The unit 31 comprises an integral electrical socket 32 and an integral electrical plug 33, electrically coupled to one another within the unit 31. In the illustrated arrangement, the integral electrical plug 33 of the unit 31 is plugged in to the first electrical socket 13 of the electrical system 1 and the first electrical plug 17 of the electrical system 1 is plugged in to the integral electrical socket 32 of the unit 31. In other words, the unit 31 is positioned between the first electrical socket 13 and the first electrical plug 17. In this respect, it is similar to a plug/socket adaptor for converting a single socket into multiple sockets or for converting a socket of one geographical region type to a socket of another geographical region type.

In this embodiment, the second current sensor 20 is located within the unit 31. The second current sensor 20 has a circuit for detecting current passing through the unit 31 , between the integral electrical plug 33 and the integral electrical socket 32. With the unit 31 positioned in the electrical system 1 as described, this electrical current is that being delivered to the first electrical appliance 15. The second wireless transmitter 23 is also located within the unit 31. It is coupled to the second current sensor 20 and has an antenna 34 for transmitting third and fourth signals and an indicator 35 for showing whether or not the second current sensor 20 and/or the second wireless transmitter 23 is operating.

The second current sensor 20 is arranged to compare the electrical current detected in the unit 31 to a second threshold current. The second wireless transmitter 23 is arranged to transmit the third signal when the electrical current detected in the unit 31 passes above the second threshold current, and to transmit the fourth signal when the electrical current detected in the unit 31 passes below the second threshold current.

The third current sensor 21 and third wireless transmitter 24 are identical to the second current sensor 20 and second wireless transmitter 23, except that the third current sensor 21 is arranged to use a third threshold current and the third wireless transmitter 23 is arranged to transmit fifth and sixth signals. Also, in the illustrated arrangement, the third current sensor 21 and third wireless transmitter 24 are arranged between the second electrical socket 14 and the second electrical plug 18 of the electrical system 1 , so as to detect the electrical current being provided to the second electrical appliance 16.

Referring to Figure 4, the wireless receiver 25 and switch 9 are integrated into a face plate 36 suitable to fitting to a housing 37 through which wires 38 of the third electrical circuit 7 pass. In this embodiment, the housing 37 is that of a back box of a conventional household electrical fitting. The wireless receiver 25 has an antenna 39 for receiving the first to sixth signals from the first, second and third wireless transmitters 22, 23, 24. The wireless receiver 25 is coupled to the switch 9, which is coupled to the wires 38 of the third electrical circuit 7 so as to couple or decouple the immersion heater 1 1 from the electrical supply 3. The wireless receiver 25 also has an indicator 40 for showing whether or not the wireless receiver 25 operating.

Referring to Figure 5, in operation, at step S1 , the first current sensor 19 detects the electrical current in the first electrical circuit 4 passing above the first threshold current. This is indicative of the renewable source of electricity 2 providing an increasing amount of electricity. At step S2, in response to the first current sensor 19 detecting the electrical current in the first electrical circuit 4 passing above the first threshold current, the first wireless transmitter 22 transmits the first signal.

The wireless receiver 25 receives the first signal and, at step S3, in response causes the switch 9 to couple the electrical supply 3 to the immersion heater 11. This means that electricity is now supplied to the immersion heater 11 , and this electricity is at least in part that provided from the renewable source of electricity 2.

At step S4, the second current sensor 20 detects the electrical current being provided to the first electrical appliance 15 passing above the second threshold current. This is indicative of the first electrical appliance 15, which in this embodiment is a kettle, being turned on. At step S5, in response to the second current sensor 20 detecting the electricity being provided to the first electrical appliance 15 passing above the second threshold current, the second wireless transmitter 23 transmits the third signal.

The wireless receiver 25 receives the third signal and, at step S6, in response causes the switch 9 to decouple the electrical supply 3 from the immersion heater 1 1.

This means that electricity is now no longer supplied to the immersion heater 1 1 , reducing the load on the electrical supply 3 such that the electrical current being supplied to the first appliance 15 is to a greater extent that provided from the renewable source of electricity 2.

At step S7, the second current sensor 20 detects the electrical current being provided to the first electrical appliance 15 passing below the second threshold current. This is indicative of the first electrical appliance 15 being turned off. At step S8, in response to the second current sensor 20 detecting the electrical current being provided to the first electrical appliance 15 passing below the second threshold current, the second wireless transmitter 23 transmits the fourth signal.

The wireless receiver 25 receives the fourth signal and, at step S9, in response causes the switch 9 to couple the electrical supply 3 to the immersion heater 11. This resumes the supply of electricity to the immersion heater 1 1 , meaning that the immersion heater is again turned on, and using electricity provided from the renewable source of electricity 2.

At step S10, the first current sensor 19 detects the electrical current in the first electrical circuit 4 passing below the first threshold current. This is indicative of the renewable source of electricity 2 providing a decreasing amount of electricity. At step S1 1 , in response to the first current sensor 19 detecting the electrical current in the first electrical circuit 4 passing below the first threshold current, the first wireless transmitter 22 transmits the second signal.

The wireless receiver 25 receives the second signal and, at step S12, in response causes the switch 9 to decouple the electrical supply 3 from the immersion heater 1 1. This means that electricity is now no longer supplied to the immersion heater 1 1 , reducing the load on the electrical supply 3 and ensuring that electricity from the electricity grid 5 is not used unnecessarily.

The sequence of operation described with reference to Figure 5 is just one possibility. Whilst the second signal is normally transmitted following the first signal, and likewise the fourth signal following the third signal and the sixth signal following the fifth signal, each pair of signals may be transmitted at any time with respect to one another, including being interleaved with one another. In order to deal with this, the wireless receiver 25 treats the first and second signals as master control signals, and the third, fourth, fifth and sixth signals as temporary override signals. That is, the wireless receiver 25 controls the switch 9 such that it only couples the electrical supply 3 to the output 10 between receiving the first signal and receiving the second signal. Outside of that time, the wireless receiver 25 controls the switch 9 to decouple the electrical supply 3 from the output 10 irrespective of receiving any of the third, fourth, fifth and sixth signals.

Between receiving the first signal and receiving the second signal, the wireless receiver 25 additionally controls the switch 9 upon receiving the third, fourth, fifth and sixth signals, as needed. In response to receiving the third signal or the fifth signal, it controls the switch 9 to decouple the electrical supply 3 from the output 10, and in response to receiving the fourth signal or the sixth signal, it controls the switch 9 to couple the electrical supply 3 to the output 10. However, any decoupling overrides any coupling, in the sense that after having received the third and the fifth signals, coupling only occurs once both the fourth and the sixth signals have been received. Similarly, if the second signal is received before the fourth and/or sixth signals are received, no coupling will occur when the fourth or sixth signals are then received.

It will be appreciated that the first to sixth signals may be different from one another, e.g. at a different frequency or containing a different code, in order that the wireless receiver 25 can distinguish between them and control the switch 9 as

appropriate. This may be achieved by using different channels around the 433 MHz frequency. However, in another embodiment, the third and fifth signals may be the same and the fourth and sixth signals may be the same, and the wireless receiver 25 may count the signals to provide the required control.

Where, as in the described embodiments, the output 10 is coupled to an immersion heater 1 1 or some similar load, it will be appreciated that the output 10 may not draw any current even when it is coupled to the electrical supply 3. For example, the immersion heater 1 1 may be thermostatically controlled only to heat water to a particular temperature. It may also be timed to only operate during certain hours of the day, or to be turned off during certain periods.

It is noteworthy that, whilst the indicators 30, 35, 40 are described above as indicating operation of the first current sensor 19 and/or the first wireless transmitter 22, the second current sensor 20 and/or the second wireless transmitter 23, and the wireless receiver 25, this may, more specifically, reflect a number of different things. In one example, it is simply an indication that power is being supplied to the respective devices, e.g. that they are turned on. However, in another embodiment, each wireless transmitter 22, 23, 24 respectively pairs with the wireless receiver 25 using a communication protocol and the indicators 30, 35 on the wireless transmitters 22, 23 indicate that this pairing has occurred. It is also noteworthy that, whilst the antennas 28, 34, 39 are shown in the drawings as being outside of the housings of the first and second wireless transmitters 22, 23 and the wireless receiver 25, the antennas may be located within the respective housings. In such embodiments, the housings should be non-conducting, e.g. of plastics material, so as not to shield the signals.

Other variations and modifications will be apparent to the skilled person. Such variations and modifications may involve equivalent and other features which are already known and which may be used instead of, or in addition to, features described herein. Features that are described in the context of separate embodiments may be provided in combination in a single embodiment. Conversely, features which are described in the context of a single embodiment may also be provided separately or in any suitable subcombination.

It should be noted that the term "comprising" does not exclude other elements or steps, the term "a" or "an" does not exclude a plurality, a single feature may fulfil the functions of several features recited in the claims and reference signs in the claims shall not be construed as limiting the scope of the claims. It should also be noted that the Figures are not necessarily to scale; emphasis instead generally being placed upon illustrating the principles of the present invention.

Claims

1. An electrical supply controller comprising:

a switch (9) arranged to selectively couple and decouple an electrical supply (3) to an output (10);

a first current sensor (19) arranged to detect when an electric current delivered from a source of electricity(2) to the electrical supply (3) exceeds a first threshold current; a first wireless transmitter (22) arranged to transmit a first signal in response to the first current sensor (19) detecting the electric current delivered by the source of electricity (2) to the electrical supply (3) exceeding the first threshold current; and

a wireless receiver (25) arranged, in response to receiving the first signal, to cause the switch (9) to couple the electrical supply (3) to the output.

2. The electrical supply controller of claim 1 , wherein the source of electricity (3) is arranged togenerate electricity from renewable energy.

3. The electrical supply controller of claim 1 or claim 2, wherein the source of electricity (3) is photovoltaic.

4. The electrical supply controller of any one of the preceding claims, wherein the output (10) is coupled to a hot water immersion heater (1 1).

5. The electrical supply controller of any one of the preceding claims, wherein the switch (9) and the wireless receiver (25) are integrated into a switching unit (36).

6. The electrical supply controller of claim 5, wherein the switching unit (36) is mountable in a back box (37) of a household electrical circuit.

7. The electrical supply controller of any one of the preceding claims, wherein the first current sensor (19) comprises a transducer (26) inductively couplable to a conductor of the current delivered by the source of electricity (2) to the electrical supply (3).

8. The electrical supply controller of any one of the preceding claims, wherein the first current sensor (19) has an interface (29) that allows the first threshold current to be adjusted.

9. The electrical supply controller of any one of the preceding claims, comprising: a second current sensor (20) arranged to detect when an electric current delivered to an electrical device (15) from the electrical supply (3) exceeds a second threshold current; and

a second wireless transmitter (23) arranged to transmit a second signal in response to the second current sensor (20) detecting the electrical current delivered to the electrical device (15) from the electrical supply (3) exceeding the second threshold current,

wherein the wireless receiver (25) is arranged, in response to receiving the second signal, to cause the switch (9) to decouple the electrical supply (3) from the output.

10. The electrical supply controller of claim 9, comprising:

a third current sensor (21) arranged to detect when an electric current supplied to another electrical device (16) from the electrical supply (3) exceeds a third threshold current; and

a third wireless transmitter (24) arranged to transmit a third signal in response to the third current sensor (21) detecting the electrical current supplied to the other electrical device (16) from the electrical supply (3) exceeding the third threshold current,

wherein the wireless receiver (25) is arranged, in response to receiving the third signal, to cause the switch (9) to decouple the electrical supply (3) from the output.

11. The electrical supply controller of any one of the preceding claims, wherein the signal(s) is/are at a frequency of approximately 433 MHz.

12. A method of controlling an electrical supply using a switch (9) arranged to selectively couple and decouple an electrical supply (3) to an output (10), the method comprising:

detecting when an electric current delivered from a source of electricity (2) to the electrical supply (3) exceeds a first threshold current;

wirelessly transmitting a first signal in response to detecting the electric current delivered by the source of electricity (2) to the electrical supply (3) exceeding the first threshold current; and,

in response to wirelessly receiving the first signal, causing the switch (9) to couple the electrical supply (3) to the output (10).