ES2324449A1 - Cooking surface having a plurality of heating elements and method for operating a cooking surface - Google Patents

Abstract

The invention relates to a cooking surface having a plurality of heating elements (10) and a control unit (12) designed to assign a plurality of the heating elements (10) to a group (14) and to regulate the heating power of the heating elements (10) at a prescribed target power. In order to provide a generic cooking surface and a method for operating a cooking surface, having a simplified and less error-prone controller, the invention proposes that the control unit (12) be provided to use a characteristic value for a total heating power generated for one of all the heating elements (10) associated with the group (14), and to compare said value to a prescribed target power for the entire group (14).

Description

Cooking field with a plurality of elements of heating and procedure for the actuation of a field Cooking

The invention relates to a cooking field with a plurality of heating elements according to the concept general of claim 1 and a method for actuation of a cooking field according to the general concept of claim 10

From WO 97/37515 a field of cooking with a plurality of heating elements, and of made with induction heating elements, and a unit of I send. The control unit is configured to assign several of the heating elements to a group and regulate a power of heating of each of the heating elements of individual way in a predetermined theoretical power. Each of the heating elements has an exciter unit own with an inverter, so that the frequencies of the heating current, with which the element of induction heating, are independently adjustable from each other to achieve the respective theoretical power of the individual heating elements.

The task of the invention consists especially of make available a cooking range according to gender as well as a procedure for operating a cooking field with a Simplified control and less susceptible to failures.

The task is solved according to the invention by the characteristics of claims 1 and 11, while secondary claims can be extracted configurations and advantageous improvements of the invention.

The invention relates in particular to a field of cooking with a plurality of heating elements and a control unit, which is configured to assign several of the heating elements to a group and regulate a power of heating of the heating elements in a power theoretical default.

It is proposed that the command unit be planned to use as parameter a parameter for a power of total heating generated by all the elements of warming assigned to the group and compare it with a power Theoretical default for the whole group. In this way, you can noticeably simplify an effort for regulation in comparison with heating power regulations conventional in which the heating power of each particular heating element is individually regulated at a predetermined value. Especially then if elements of particular heating of those arranged especially in a grid are covered only in a fraction by the battery of cooking to be heated, and if in procedures Conventional heating power regulation the heating power absorbed by the element of heating is regulated at a value dependent on this fraction, Regulation can be greatly simplified.

The invention is based in particular on the knowledge that the power absorption of elements of heating covered only in a fraction with the battery of cooking that has to be heated is very dependent on this fraction. Especially in the case of induction heating elements, but also in the case of heating elements by radiation, the heating power absorbed with parameters of equal performance in the rest is a growing function of strictly monotonous way of covering fraction. In a group of heating elements that are gathered in an area heating and heat together a piece of cooking battery, the power absorption of elements of Covered heating only partially adjusts automatically therefore at a lower value than the heating power of heating elements completely covered. A command or explicit regulation of the heating power of elements heating partially covered at a lower value may Therefore, it should be removed advantageously.

By "intended" is to be understood in this context also "configured" and "arranged". Unit of control can be provided for the regulation according to the invention through a hardware circuit, in which for example the Group heating elements are connected in parallel, or by appropriate command software that can determine the total heating power as a linear combination fixed default of the heating powers of the individual heating elements. Each type is usable of regulator that is reasonable to the expert, that may be adapted to the response behavior of the elements of heating.

The term regulation must describe in this context especially closed regulator circuits. The utilization of the total heating power as regulated magnitude implies especially regulator circuits in which all parameters operating heating elements are determined by default parameters and by total heating power encoded in the parameter, without however, not by parameters for the heating power of particular heating elements or other parameters.

Due to the strong dependence on the power of heating of the degree of coverage, the advantages of invention are especially effective then if the elements of heating are configured as heating elements by  induction.

Losses can be avoided by destructive interference if the control unit is configured for, for the regulation of the total heating power, simultaneously modify a heating frequency of Induction heating elements.

Also if mainly the group can also understand subgroups for heating several areas of heating, flexible regulation can be carried out, adapted to a special cooking battery element, especially then if the group of heating elements forms a zone of heating for heating a piece of battery cooking.

A simple regulation of many heating elements if the control unit is configured for, for the regulation of the power of total heating of the heating elements, modify in the same measure the values of an operating parameter of each of all heating elements.

You can get a power delivery differentiated if the control unit is configured to operate at least one of the heating elements assigned to a group with a heating power other than at least one second of the heating elements assigned to the group.

This applies especially then if the unit control is configured to activate heating elements radially outside the group with a heating power greater than radially internal heating elements of the group. In this way, radiation losses greater than radially external heating elements can be compensated, and a homogeneous temperature of the cooking battery base.

In addition, at least the heating element with lower heating power can be connected and periodically disconnected for setting a relationship predetermined heating power of a first heating element with respect to the power of heating of a second heating element, so that the relationship of the duration of the phases, in which the first heating element is connected, with respect to the duration of the phases, in which the second element of heating is connected, corresponds to the relationship default

Regulation can be achieved especially simple if a regulator circuit that uses as magnitude regulated the parameter for the total heating power is the only regulating circuit that affects the heating power of the heating elements. Also the duration of the phases mentioned above can be determined for example in a circuit regulator.

Another aspect of the invention relates to a procedure for operating a cooking field with a plurality of heating elements, in which several of the heating elements are assigned to a group, and in which a heating power of the heating elements is regulated in a predetermined theoretical power.

For the improvement of the procedure, it is proposed, inter alia, that a parameter for a total heating power generated by all the heating elements assigned to the group be used as a regulated quantity and compared with a predetermined theoretical power for the whole group.

Other advantages are taken from the following Description of the drawings. In the drawing a Example of embodiment of the invention. The drawing, the description and the claims contain numerous features in combination. The expert will consider the characteristics so advantageous also separately and will bring them together in other combinations reasonable.

It shows:

Fig. 1 a cooking field with a plurality of heating elements and a control unit,

Fig. 2 the cooking field of figure 1 with a heating zone, in which a partial group of elements radially heated interior is powered with a heating power less than a partial group of elements radially external heating,

Fig. 3 a schematic representation of a temporal progression of heating currents of the first group partial heating elements and the second partial group of heating elements and

Fig. 4 a schematic representation of a regulator circuit for the actuation of a cooking field according to figures 1 to 3.

Figure 1 shows a cooking field with a plurality of heating elements 10 and a control unit 12, which is configured to assign several of the elements of heating 10 to a group 14 and regulate a power of heating of heating elements 10 in a power theoretical default. The heating elements 10 are induction heating elements that are arranged in a grid with rectangular meshes. In control unit 12 a search program that uses the elements is implemented heating 10 as inductive sensors for the detection of 16a, 16b and define ferromagnetic cooking battery parts heating zones depending on the results of the search program, each of which contains the elements heating 10 that are completely covered or in more than a predetermined fraction by the base of the battery piece of cooking 16.

The heating zones defined by the search program are represented in figure 1 by scratches of the heating elements 10, which are gathered in a group that forms the respective heating zone.

A user can adjust a power of desired total heating of the heating zone, that is, of the heating elements 10 gathered in group 14 that forms the heating zone through a user interface 18 indicated here only schematically, for example via buttons or a touch screen.

According to the invention, the control unit 12 is configured through a software and hardware configuration suitable for using a parameter for a regulated quantity total heating power generated by all the elements of heating 10 assigned to group 14, and compare it with a default theoretical power for the entire group 14.

To each of the heating elements 10 a high heating current is supplied frequency (figure 3) through an inverter 20.1 - 20.N (figure 4) not explicitly represented here, in which the power of heating of heating elements 10 is also very dependent on the heating frequency of the current heating through the amplitude of the current of heating, and due to the steep dispersion curve in comparison of the ferromagnetic material of the base of the piece of cooking battery 16.

The control unit 12 captures each time the power absorption of inverters 20.1 - 20.N, for example by capturing the loss angles in the coils of induction, and adds the individual powers of the elements of  heating 10 of the group 14 concerned to determine a value real V_ {real} for the total heating power of the group 14 heating elements 10. Next, the unit command 12 compares the real value V_ {real} captured in such a way the total heating power in a comparator unit 22 (figure 4) with a predetermined theoretical value V_ {Theoretical} of the total heating power, and reduces the powers of heating of the individual heating elements 10 in the same measure if the theoretical value V_ {Theoretical} is less than the real value V_ {real}, or increases the heating power of the individual heating elements 10 if the theoretical value V_ {Theoretical} is greater than the real V_ {.

In alternative embodiments, via a serial or parallel connection can be determined directly and without addition a parameter for the power of total warming

The control unit 12 uses to regulate the total heating power especially the frequency of heating of the induction heating elements that modify it simultaneously, so that the frequency of heating is the same in all heating elements 10 assigned to a heating zone. The phases of the currents 10 heating elements adjacent heating they are directly opposite each other, so that they can avoid destructive interference of magnetic fields generated by heating elements 10 adjacent.

In the regulation of the heating power total, the heating powers captured in the inverters Individuals 20.1 - 20.N are not determined individually by the control unit 12, but are only added in a addition step schematically represented in figure 4. Due to the different degree of coupling of the elements of heating 10 to the base of the cooking battery piece 16, to Despite the equal parameters of the supply current, the power really dissipated in induction coils is different. In the example represented in Figure 2, the element heating 10a is covered by the battery part of cooking only partially while the element of heating 10b is completely covered. Therefore the heating element 10b will transmit to the battery part of cooking 16 automatically during operation a heating power almost twice greater than the element of heating 10a partially covered.

More accurately said, the control unit 12 is configured through its command software for, to regulate the total heating power of the elements of heating 10, modify the values of a operating parameter of each of all the elements of heating 10. In the simplified embodiment, described above, the control unit 12 modifies the frequency of heating simultaneously, so that the frequencies of heating of the different heating elements 10 They are always in the 1: 1 ratio. The amplitude of the current of warming can remain constant at least essentially.

If the size of the heating zone exceeds a predetermined threshold value, so that an element of medium heating be surrounded by four sides of others heating elements 10, assigned to the same area of heating, the control unit 12 determines a power of medium heating over a period of an element of heating 10 assigned to a first partial group 14a, of such way that differs from the heating power of a second partial group 14b of heating elements 10.

The various partial groups 14a, 14b are delimited from each other in an example of figure 2 by Different scratches.

The control unit 12 determines in particular the average heating powers of the different partial groups 14a, 14b, so that a partial group 14a of elements of heating 10 externally radially is operated with a heating power greater than a partial group 14b of heating elements 10 radially inside the group 14.

The control software of the control unit 12 used to set a default ratio of the heating power of a first heating element 10 of the first partial group 14a with respect to the power of heating of a second heating element 10 of the second partial group 14b a periodic connection and disconnection of heating elements 10. When this happens, the element of heating 10 is connected and disconnected periodically with the lower heating power, so that the ratio of the duration of the phases, in which the first element of heating is connected, with respect to the duration of the phases, in which the second heating element is connected, corresponds to the default relationship.

If for example the first element of heating 10 remains connected continuously, the relationship mentioned above corresponds to the relationship of the duration of the phases, in which the first element of heating 10 is connected, with respect to the duration of the period.

In an exemplary embodiment represented in the Figure 3, the heating frequency is in the region of MHz and does not correspond to the time scale of the representation, while the duration of the period may be A few seconds In the example, the duration of the period is 2 seconds The partial group 14b of the elements of heating 10 means, whose heating current is schematically represented in the lower curve, they are connected and disconnected in the example in phases with a duration of one second in the change, while the 14th partial group of heating elements 10 externally radially remains Connected continuously.

The average heating power during the duration of the heating elements period 10 radially interiors can be divided into two in this way in comparison with the heating power of the elements of heating 10 outdoors radially. If the power of total heating is modified, the heating powers means are changed to the same extent, since the parameters for the determination of the duration of the phases, that is, the duration of the phases and moments of connection and disconnection, They may remain unmodified.

The regulator circuit that uses the parameter for the total heating power as a regulated quantity is, as stated above, the only regulatory circuit that affects The heating power of the heating elements 10.

A regulatory circuit represented schematically for the operation of the cooking field is depicted in figure 4. A comparator unit 22 determines a difference between the theoretical value V_ {theoretical} and the actual value V_ {real} and the control unit 12 determines the frequency of heating of the heating currents generated by the inverters 20.1 - 20.N so that the real value V_ {real} is modify in the direction of the theoretical value V_ {theoretical}.

Order signals, which command unit 12 gives investors 20.1 - 20.N, they are identical at least in the inside the partial groups 14a, 14b described above. He real value V_ {real} is a parameter for the power of total heating, and is determined in addition step 24 by adding the heating power of the individual heating elements 10 determined so dependent on the angle of loss or other parameters.

Another aspect of the invention relates to a procedure for operating a cooking field of the type described above, comprising a plurality of elements of heating 10. According to the procedure, several of the heating elements 10 to a group 14 so dependent on the search program, and a power of heating of heating elements 10 is regulated in a predetermined theoretical power.

For the improvement of the procedure, it is proposed inter alia that a parameter for a total heating power generated by all heating elements 10 assigned to group 14 be used as a regulated quantity, and that it be compared with a predetermined theoretical power for the whole group 14.

Reference symbols

10

Heating element

12

Control unit

14

Group

14 to

Partial group

14b

Partial group

16

Cooking battery part

16th

Cooking battery part

16b

Cooking battery part

18

User interface

twenty

Investor

22

Comparator unit

24

Addition step

Claims (10)

1. Cooking range with a plurality of heating elements (10) and a control unit (12), which is configured to assign several of the heating elements (10) to a group (14) and regulate a heating power of the heating elements (10) in a predetermined theoretical power, characterized in that the control unit (12) is intended to use as a regulated quantity a parameter for a total heating power generated by all the heating elements (10) assigned to the group (14) and compare it with a theoretical power (V_ {theoretical}) predetermined for the whole group (14). 2. Cooking field according to claim 1, characterized in that the heating elements (10) are configured as induction heating elements. 3. Cooking field at least according to claim 2, characterized in that the control unit (12) is configured to simultaneously modify a heating frequency of the induction heating elements for the regulation of the total heating power. 4. Cooking field according to one of the preceding claims, characterized in that the group (14) of heating elements (10) forms a heating zone for heating a piece of cooking battery (16). 5. Cooking field according to one of the preceding claims, characterized in that the control unit (12) is configured to modify the values of an operating parameter of each of all the heating elements (10) to the same extent for the regulation of the total heating power of the heating elements (10). 6. Cooking field according to one of the preceding claims, characterized in that the control unit (12) is configured to operate at least one of the heating elements (10) assigned to a group (14) with a different heating power that at least one second of the heating elements (10) assigned to the group (14). 7. Cooking field according to claim 5, characterized in that the control unit (12) is configured to operate external heating elements (10) radially of the group (14) with a heating power greater than internal heating elements (10) radially of the group (14). 8. Cooking field according to one of the preceding claims, characterized in that the control unit (12) is configured to periodically connect and disconnect at least the heating element (10) with the lower heating power for setting a ratio predetermined of the heating power of a first heating element (10) with respect to the heating power of a second heating element (10), such that the ratio of the duration of the phases, in which the first element heating (10) is connected, with respect to the duration of the phases, in which the second heating element (10) is connected, corresponds to the predetermined ratio. 9. Cooking field according to one of the preceding claims, characterized in that a regulating circuit that uses the parameter for the total heating power as a regulated quantity is the only regulating circuit that concerns the heating power of the heating elements (10 ). 10. Procedure for actuating a cooking field with a plurality of heating elements (10), in which several of the heating elements (10) are assigned to a group (14), and in which a power of heating of the heating elements (10) is regulated in a predetermined theoretical power, characterized in that a parameter for a total heating power generated by all the heating elements (10) assigned to the group (14) is used as a regulated quantity and is compared to a predetermined theoretical power (V_ {theoretical}) for the whole group (14).