GB2511835A

GB2511835A - Power Switching Device and Method

Info

Publication number: GB2511835A
Application number: GB1304683.4A
Authority: GB
Inventors: John Kennedy; Craig Nutter
Original assignee: ESSE ENGINEERING Ltd
Current assignee: ESSE ENGINEERING Ltd
Priority date: 2013-03-15
Filing date: 2013-03-15
Publication date: 2014-09-17
Also published as: GB201304683D0

Abstract

A cooking or heating device (Fig. 1, 10) comprises hotplates 12, 14 and ovens 20, 22 heated by one or more elements, where a power supply 28 provides each element with power in a time division manner between the elements. A microcontroller 30 may control the supply of power alternately to each element using TRIACs 32, 34, 36, 38. The device 10 may be a domestic stove or range using a mains power supply 28 and may comprise at least two hotplates 12, 14 and ovens 20, 22 heated by at least one element, which may be formed from a heat conducting material. The device may include a control panel 24 for controlling the power supply to the heating elements. The power supplied to the device may be pulsing and divided equally between the number of hotplates and ovens that are on at the same time. Alternatively if only one hotplate or oven is on then power may be supplied continuously. The device can therefore use conventional mains power supplies without the supply becoming overloaded.

Description

Power Switching Device and Method This invention relates to a cooking and/or heating device, particularly, but not limited to, a cooking/heating device which uses a mains power supply.

Most existing cooking/heating devices operate by drawing power from a mains supply via a standard plug and socket arrangement, whether in domestic or industrial situations. When the plug is inserted into the socket and turned on, current flows into the cooking/heating device and the various hotplates and/or ovens of the device may be operated by the user to provide heat when desired.

Most range cookers that include oven/s plus hotplates require at least a 35 Amp power supply and are hard wired to a fused spur of the electrical supply, so do not come supplied with electrical plugs to go into standard sockets. There are existing examples of cookers capable of being "plugged in" and the total power they can draw from the standard electrical socket if their individual ovens/hotplates are all on full is 3kw. However the disadvantage is that this is a sum of the maximum of each oven/hotplate and they are unable to make better use of any spare power if one or more zones are either not in use or up to temperature.

It is an object of the present invention to address the above mentioned disadvantages.

According to an aspect of the present invention there is provided a cooking/heating device, the device having one or more hotplates and/or ovens, each operable to be heated by one or more elements, wherein each element is powered by a power supply and the power supply is operable to be supplied in a time division manner between the one or more elements.

The cooking/heating device may encompass any known device suitable for cooking and/or heating, for example a cooker, oven, burner, stove, range, etc. Suitably, the device uses a mains power supply, preferably therefore the device is a domestic cooking/heating device rather than an industrial device. More preferably the cooking/heating device is a domestic range.

By mains power supply' it is meant the standard electricity supply received in domestic environments, typically via receptacles or outlets such as plugs and sockets wired into buildings. For example, in the UK, the mains power supply is typically 230V at 50Hz, in the US the mains power supply is typically 120V at 60Hz, in Japan the mains power supply is typically bOy at 50 or 60Hz.

Preferably the cooking/heating device comprises at least two hotplates and/or ovens, more preferably at least three hotplates and/or ovens, still more preferably four hotplates and/or ovens.

In a particularly preferred embodiment, the cooking heating device comprises two ovens and two hotplates.

Suitably each hotplate and/or oven is heated by at least one element. However, each hotplate and/or oven may be heated by any number of elements necessary to heat the hotplate and/or oven, for example, one oven may be heated by three or four different elements.

Preferably the at least one element is a heating element.

Suitably therefore, the at least one element is formed from a heat conducting material, for example, metals such as steel, iron, copper, tungsten, etc. Suitably, the cooking/heating device of the invention may be operated when desired to turn on the element/s for a given hotplate and/or oven. Preferably the element/s for a given hotplate and/or oven are turned on in unison such that, for example, when the oven which may comprise four elements is turned on, all four elements are turned on together.

Suitably, the cooking/heating device is operated by the user, suitably by any known means allowing a user input, including for example switches, dials, buttons etc. said means comprising the ability to turn on the hotplate and/or ovens of the device.

By turn on' it is meant that power is supplied to the one or more elements of the hotplate/and or ovens by the operation of a user input, suitably to heat the one or more elements.

Suitably, the power supplied to the one or more elements of the hotplate and/or ovens is pulsing, and/or supplied in a time-division manner.

Preferably the pulsing power supply is divided between, preferably substantially equally between, the number of hotplates and/or ovens which are on at the same time.

Preferably, if only one hotplate or oven is turned on, the power supply is continuous to that one hotplate. Preferably, therefore, in any given time period the power is supplied to the one hotplate or oven for the full time period, until a desired temperature is reached.

Preferably, if two hotplates and/or ovens are turned on, the power supply is supplied alternately, preferably over two substantially equal periods, between the two hotplates and/or ovens in pulses of, for example, 0.5 seconds. Preferably, therefore, in any given time period the power is supplied to each hotplate and/or oven for half the time period.

Preferably, if three or more hotplates and/or ovens are turned on, the power supply is supplied for three substantially equal periods between each hotplate and/or oven. Preferably, for three hotplates and/or ovens, the power is pulsed cyclically for three periods of approximately, for example, 0.5 seconds.

Preferably, for four hotplates and/or ovens, the power is pulsed cyclically for four substantially equal periods,for example of approximately 0.5 seconds.

Power is a function of the current and voltage of a supply as determined by the equation P = IV. Preferably, therefore, the power supply is pulsed, or time-divided, by pulsing the current supplied to the one or more hotplates and/or ovens.

Preferably the pulsing power supply is supplied to the one or more hotplates and/or ovens by a circuit comprised within the cooking/heating device, preferably the circuit comprises a device suitable for dividing the mains power supply between the required hotplate/s and/or oven/s over a given time period such that each receives a substantially equal time share of the mains power supply. Preferably the circuit uses a triac for each section to be powered. Preferably a PlC (RTM) microcontroller is used to control the triacs in the various zones. Software in the microcontroller controls the firing of the triacs.

Advantageously, each hotplate and/or oven that is required by the user to be turned on still receives the full amount of power supply required, but in a regular pulse, such that at any one moment in time, only one of the hotplate/s and/or oven/s is receiving power from the mains supply.

A further advantage of the invention is that when use of only one of the hotplates/ovens is required it can be given the full power that it requires. An alternative solution to powering multiple electric elements in a cooker/stove, as discussed in the introduction, is to limit a power supply to an individual section so that all sections can be powered simultaneously. The solution provided herein uses time division to allow a full power supply for rapid heating up to a required temperature when only one or two (for example) of the sections are required, but still allowing all sections to be used (at a lower power and so heating more slowly) when desired.

The solution allows a cooker/heating device to be powered by a domestic power supply and to be used to the maximum power for a given oven/hotplate in some circumstances, whilst still allowing all ovens/hotplates to be used concurrently with reduced performance.

Therefore, such an arrangement avoids the problem of an excessive power demand on the main supply and avoids the problem of the fuse blowing when the cooking/heating device is turned on at the mains.

For a better understanding of the invention, and to show how embodiments of the same may be carried into effect, reference will now be made, by way of example, to the accompanying diagrammatic drawings in which: Figure 1 is a schematic diagram of an cooker with two hotplates and two ovens; and Figure 2 is a schematic circuit diagram of a power supply and control circuitry of the oven shown in Figure 11.

Figure 1 shows and cooker 10, comprising two hotplates 12 and 14 with respective cover 16 and 18. The cooker 10 also has two ovens 20 and 22. A control panel 24 is used to control the heating of the two hotplates 12 and 14 and the two ovens 20 and 22 by manipulation of control knobs in the usual way.

Control circuitry is located behind a service door 26. The control circuitry is shown schematically in Figure 2.

A power supply 28 provides power to a microcontroller 30, which controls the supply of power to four triacs 32, 34, 36 and 38, each of which respectively supplies power to one of the hotplates 16/18 or ovens 20/22.

In use the microcontroller 30 supplies power from a mains supply to which the cooker 10 is connected under control of the control panel 24.

When a user selects only one of the hotplates 16/18 or ovens 20/22 for operation, the microcontroller 30 supplies full power to the selected hotplate/oven until it reaches a set temperature. Thus, the chosen hotplate/oven achieves its working temperature in a timely way.

When a user selects two of the hotplates/ovens for operation, the microcontroller 30 controls the relevant triacs of the two hotplates/ovens to divide the power supply substantially equally between the two as long as they demand power for heating, thereby receiving half the madmum power available. The division of power is achieved by a time division, in which full power is given to one hotplate/oven for a period of, for example, 0.5 seconds, followed by full power to the other hotplate/oven for 0.5 seconds. The supply cycle is then repeated. Thus, the two hotplates/ovens reach their required temperatures two times faster than if the power supply had been limited to supplying a quarter of the maximum available power to each of the two hotplates and two ovens.

The time division may be set at a different time period to the 0.5 seconds mentioned above.

For example, the time period may be much shorter at, for example, 0.1 seconds. The period may be chosen to reduce unwanted heating of the control equipment.

When a user selects three of the hotplates/ovens for operation, the microcontroller 30 controls the relevant triacs of the three hotplates/ovens to divide the power supply substantially equally between the three as long as they demand power for heating, thereby receiving a third of the maximum power available. The division of power is achieved by a time division, in which full power is given to one hotplate/oven for a period of, for example, 0.5 seconds, followed by full power to the second hotplate/oven for 0.5 seconds and then full power to the third hotplate/oven for 0.5 seconds. The supply cycle is then repeated. Thus, the three hotplates/ovens reach their required temperatures faster than if the power supply had been limited to supplying a quarter of the maximum available power to each of the two hotplates and two ovens.

When a user selects all four of the hotplates/ovens for operation, the microcontroller 30 controls the relevant triacs of the four hotplates/ovens to divide the power supply substantially equally between the four as long as they demand power for heating, thereby receiving a quarter of the maximum power available. The division of power is achieved by a time division, in which full power is given to one hotplate/oven for a period of, for example, 0.5 seconds, followed by full power to the second hotplate/oven for 0.5 seconds, then full power to the third hotplate/oven for 0.5 seconds and full power to the fourth hotplate/oven for 0.5 seconds. The supply cycle is then repeated. Thus, the four hotplates/ovens reach their required temperatures at the same speed as if the power supply had been limited to supplying a quarter of the maximum available power to each of the two hotplates and two ovens.

In view of the above operation scheme the cooker 10 functions more quickly for three out of the four scenarios for heating the hotplates/ovens when compared to the cooker being controlled by supplying a maximum of one quarter of full power to the hotplates/ovens. Thus, considerable performance advantages are achieved for a relatively small extra cost in control circuitry.

Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

Claims: 1. A cooking/heating device having one or more hotplates and/or ovens, each operable to be heated by one or more elements, wherein each element is powered by a power supply and the power supply is operable to be supplied in a time division manner between the one or more elements.
2. The cooking/heating device of claim 1, wherein the device is a cooker, oven, burner, stove, or range.
3. The cooking/heating device of any preceding claim, wherein the device uses a mains power supply.
4. The cooking/heating device of any preceding claim, wherein the cooking/heating device is a domestic range.
5. The cooking/heating device of any preceding claim, wherein the device comprises at least two hotplates and/or ovens. o 20
6. The cooking/heating device of any preceding claim, wherein the cooking/heating device comprises two ovens and two hotplates.
7. The cooking/heating device of any preceding claim, wherein each hotplate and/or oven is heated by at least one element.
8. The cooking/heating device of any preceding claim, wherein the at least one element is a heating element.
9. The cooking/heating device of any preceding claim, wherein the at least one element is formed from a heat conducting material, such as steel, iron, copper ortungsten.
10. The cooking/heating device of any preceding claim, wherein the device is operable to turn on the element/s for a given hotplate and/or oven when desired, wherein the tuming on comprises supplying power to the one or more elements of the hotplate and/or ovens by the operation of user input.
11. The cooking/heating device of claim 12, wherein the element/s for a given hotplate and/or oven are operable to be turned on in unison.B
12. The cooking/heating device of any of claims 12 to 14, wherein the power supplied to the one or more elements of the hotplate and/or ovens is pulsing.
13. The cooking/heating device of claim 15, wherein the pulsing power supply is divided between the number of hotplates and/or ovens which are on at the same time.
14. The cooking/heating device of claim 16, wherein the pulsing power supply is divided substantially equally between the number of hotplates and/or ovens which are on at the same time.
15. The cooking/heating device of any one of claims 12 to 17, wherein when only one hotplate or oven is tumed on, the power supply is substantially continuous to that one hotplate.
16. The cooking/heating device of claim 18, wherein in any given time period the power is supplied to the one hotplate or oven for the full time period, until a desired temperature is reached. r

0 20
17. The cooking/heating device of any one of claims 17 to 19, wherein when two hotplates and/or ovens are turned on, the power supply is supplied alternately between the two hotplates so that in any given time period the power is supplied to each hotplate and/or oven for half the time period.
18. The cooking/heating device of any one of claims 17 to 20, wherein when three or more hotplates and/or ovens are turned on, the power supply is supplied for three substantially equal periods between each hotplate and/or oven.
19. The cooking/heating device of any one of claims 17 to 21, wherein when four hotplates and/or ovens are turned on, the power is pulsed cyclically for four substantially equal periods.
20. The cooking/heating device of claim 21 or 22, wherein the substantially equal period is approximately 0.5 seconds.
21. The cooking/heating device of any preceding claim, wherein the power supply is pulsed, or time-divided, by pulsing the current supplied to the one or more hotplates and/or ovens.
22. The cooking/heating device of claim 24, wherein the device further comprises a circuit for supplying the pulsing power supply to the one or more hotplates and/or ovens.
23. The cooking/heating device of claim 25, wherein the circuit comprises a device suitable for dividing the mains power supply between the required hotplate/s and/or oven/s over a given time period such that each receives a substantially equal time share of the mains power supply.
24. The cooking/heating device of claim 25 or 26, wherein the circuit uses a triac for each section to be powered.
25. The cooking/heating device of claim 27, wherein a PlC (RTM) microcontroller is used to control the triacs in the various zones.
26. The cooking/heating device of claim 28, wherein software in the microcontroller controls the firing of the triacs. rN (4