WO2003034789A2

WO2003034789A2 - A system for the coordinated control of electric cooktop plates

Info

Publication number: WO2003034789A2
Application number: PCT/IT2002/000661
Authority: WO
Inventors: Ennio Mezzopera
Original assignee: Tecnowind S.P.A.
Priority date: 2001-10-17
Filing date: 2002-10-15
Publication date: 2003-04-24
Also published as: WO2003034789A3; ITMC20010102A1; AU2002353491A1

Abstract

The present invention refers to a system for the coordinated control of electric cooktop plates, capable of coordinating the alternate operation phases of the simultaneously activated plates, in such a way that the switching on phases of one plate coincide with the switching off phases of the other plates, permitting the simultaneous switching on of the various plates as long as the total power consumption of the plates does not exceed the maximum permitted power set for the cooktop.

Description

A system for the coordinated control of electric cooktop plates.

The present application refers to a system for the coordinated control of electric cooktop plates.

The new control system has been devised to improve control and operation of electric cooktop plates, especially in terms of energy saving. The advantages of the present invention will become evident after a short description of the operating principle of traditional electric cooktop plates.

As it is known, cooktops are typically composed of four electrically heated plates. The temperature of the plates is subject to inertia, meaning that heat is maintained for a period of time after the disconnection of power supply.

It must be noted that the duration of the switching off phase of the plate after switching on depends on the temperature set for the plate, i.e. the higher the temperature is, the shorter the switching off phase will be. Today cooktops are electronically controlled to reduce electric consumption. More precisely, once the user has set the temperature of the plate, traditional electronics alternates the switching on and switching off phases of the plate, while maintaining it at the desired temperature.

In practical terms each plate is switched on and off by means of relays (electromechanical switches) associated with the plates and cooperating with electronics.

It appears evident that in the current technology the duration of the switching on and switching off phase of the plate is not random and depends on the temperature set by the user, meaning that the higher the temperature is, the longer the switching on time will be, and vice versa. If the maximum temperature value is set for the plate, the switching off phases are dramatically reduced, if not eliminated. This operating principle is autonomously applied to each cooktop plate, without taking into consideration the status (on or off) of the other plates.

If the four cooktop plates operate contemporaneously, since their switching on and off phases are not chronologically misaligned, except for a very improbable combination, most of the time two, three or even four plates will be in the switching on phase simultaneously.

In view of the above, electric cooktops have different levels of "maximum permitted" power, with 2.5 - 3.5 - 4.5 Kw for the three levels respectively and the maximum power (approximately 6/7 Kw) for the fourth level.

If the user wants to switch on one plate only, the cooktop can be maintained at the first power level, and then pass to higher levels (up to the last one), to activate two, three or four plates at the same time. In particular, if the four plates are in the switching on phase, power consumption is quite high - i.e. equal to the sum of the power values of the different plates of the cooktop (generally around 6-7 Kw) - and, most of all, cannot be controlled by the user in real time.

As mentioned above, the purpose of the invention is to devise a control system for electric cooktop plates based on the following innovative operating principle: to co-ordinate the operation of each plate with the operation of the other plates based on the maximum power value discretionary set by the user as maximum energy consumption permitted for the cooktop. If the user sets 2.5 Kw as maximum power, it appears evident that the user cannot switch on the two plates (one with 2.5 Kw and one with 1.5 Kw) simultaneously, since the sum of the power values (equal to 4 Kw) would exceed the set maximum power value (equal to 2.5 Kw).

On the contrary, the control system of the invention can advantageously allow for the simultaneous use of the two plates, with a power value lower than the maximum permitted value. The system takes advantage of the cyclic operation of the electric plates, according to which, although it operates continuously, each plate alternates switching on and switching off phases, by taking advantage of thermal inertia. Practically speaking, the operating principle of the new control system is to coordinate the operation of two simultaneously activated plates so that the switching on phase of one plate coincides with the switching off phase of the other plate.

To this end, when the two plates are in different operating phases (switching on and switching off, respectively), the power that is not used by the plate in switching off phase (1.5 Kw) is completely deviated to the plate in switching on phase (2.5 Kw), which can therefore use the 2.5 Kw power value set by the user to get to the maximum heating temperature.

When the second plate is in the switching off phase, the first plate (1.5 Kw) can use the available power to get to the maximum heating temperature.

With the plates set to get to the maximum heating temperature, it is not said that the duration of the switching off phase of the plate will exactly coincide with the duration of the switching on phase of the other plate. In case of no coincidence, the switching phases of the two plates may overlap, thus involving total power consumption (1.5 + 2.5 Kw) higher than the maximum permitted level set for the cooktop.

In this case the control system of the invention allows the user to "realign" the switching on phase of one plate with the switching off phase of the other plate manually. This can be obtained by simply reducing the heating temperature of one or both plates with the adjustment knob.

As mentioned earlier, the lower the heating temperature of the plate, the longer the time between two consecutive switching on phases will be. In this way operation intervals of the two plates are set with such a duration that allows for the "perfect" combination of the switching on phase of one plate with the switching off phase of the other plate.

For illustrative purposes the two plates are indicated with P1 and P2 in the example and the heating temperature level set by the user on plate P2 requests a switching on phase longer than the switching off phase of plate P1.

In this case the control system of the invention informs the user with acoustic and/or luminous signals that the two plates P1 and P3 cannot be simultaneously maintained at the temperature values set with the knobs.

Moreover, the cooktop is provided with a display that shows the maximum temperature value that can be used on plate P2 to maintain it in operation together with plate P1 , in the presence of the maximum permitted power level set for the cooktop. The maximum temperature value that can be used for plate P2 is obviously lower than the value initially set by the user.

It must be noted that the electronic control unit of the control system of the invention can provide the user with information to set the switching on phase of plate P2 to a lower duration compatible with the switching off phase of P1 , by reducing the temperature level set for plate P2.

If the attempt is not successful or if the user intends to use the maximum heating temperature of the plates, the system of the invention will allow the user to increase the maximum power level of the cooktop by means of a specific control. If the cooktop has been set with maximum permitted power of 2.5 Kw, the user can activate the control to get the cooktop to 3.5 Kw maximum permitted power, it being provided that the control system of the invention will automatically get the cooktop to the original lower maximum permitted power, once that the electrical plates have been deactivated. Although the operating principle of the system of the invention has been so far described with reference to the coordinated control of two plates, it must be noted that the system can be used to coordinate the simultaneous operation of three or more plates of the same cooktop.

If, for example, the user wants to switch on a third plate while two plates are in operation, the management system of the invention will "insert" the switching on phase of the third plate in the switching off phases of the first two plates.

Also in this case the operation phases of the three plates may overlap, in such a way that the total power consumption exceeds the maximum permitted power set for the cooktop. And also in this case the user will attempt to restore compatibility between total power consumption and maximum permitted power by means of the adjustment knobs of the cooktop in order to decrease heating temperature.

If the attempt is not successful, or if the user does not intend to reduce the heating temperature of the plates, the control system of the invention will inform the user that the cooktop must be set with higher maximum permitted power.

Finally, it must be noted that, in the case of simultaneous activation of three or more plates, the electronic control unit can automatically overlap the switching on phases of the two plates with lower total power consumption, if the switching on phases of two plates at least must coincide.

Claims

1 ) A system for the coordinated control of electric cooktop plates, of the type comprising an electronic control unit capable of alternating switching on and switching off phases on each plate, while maintaining the temperature values set by the user, characterized in that the control unit coordinates the alternate operation phases of the simultaneously activated plates, in such a way that the switching on phases of one plate coincide with the switching off phases of the other plates, permitting the simultaneous switching on of the various plates as long as the total power consumption of the plates does not exceed the maximum permitted power set for the cooktop, it being provided that, if the maximum permitted power is exceeded, the control unit can inform the user with acoustic and/or luminous signals that the maximum permitted power of the cooktop must be set at a higher value.

2) A system for the coordinated control of electric cooktop plates according to claim 1 , characterized in that it comprises a display that shows the maximum temperature value to be assigned to the simultaneously activated plates to permit simultaneous operation with total power consumption compatible with the maximum permitted power set for the cooktop in that particular moment.

3) A system for the coordinated control of electric cooktop plates according to claim 1, characterized in that it allows the user to instantaneously modify the maximum permitted power set for the cooktop form a lower level to a higher level.

4) A system for the coordinated control of electric cooktop plates according to claim 1 , characterized in that it can get the cooktop back to the lower maximum permitted value once the plates are deactivated. 5) A system for the coordinated control of electric cooktop plates according to claim 1 , characterized in that, in case of simultaneous activation of three or more plates, the electronic control unit can automatically overlap the switching on phases of the two plates with lower total power consumption, if the switching on phases of two plates at least must coincide.