WO2005069688A2

WO2005069688A2 - Method for triggering heating elements, device, and cooking hob

Info

Publication number: WO2005069688A2
Application number: PCT/EP2005/000185
Authority: WO
Inventors: Klaus-Wolfgang Klingner; Martin Baier; Martin Bellm
Original assignee: E.G.O. Elektro-Gerätebau GmbH
Priority date: 2004-01-14
Filing date: 2005-01-12
Publication date: 2005-07-28
Also published as: DE102004003126B4; WO2005069688A3; DE102004003126A1

Abstract

Disclosed is a method that makes it possible to operate a subarea (30, 32) of a cooking hob, which comprises several partial elements (30a, 30b, 30c, 32a, 32b, 32c, 32d, 32e, 32f, 32g), at a freely selectable power, said power being evenly distributed across the entire subarea, even when the heating elements (30a, 30b, 30c, 32a, 32b, 32c, 32d, 32e, 32f, 32g) are able to release only power with discrete power stages. According to the inventive method, some heating elements are operated at maximum power while one heating element is operated in a clocked mode if possible and the remaining heating elements remain without power.

Description

Description Control method for heating elements and device as well as hob

Field of application and state of the art

The invention relates to a control method for a partial area of a heating surface with the features of the preamble of claim 1 and to a device and a hob, in which the control method is used.

In modern cooktops with several cooktops, each with one or more heating elements, the power output of the cooktops is controlled by hiding individual half-waves in the AC supply depending on a specified target output for the heating elements, so that the desired target output is not achieved by the hidden half-waves is reached. The disadvantage of this solution is that, with an increasing number of heating elements, very large fluctuations in the power consumption of the hob can occur if several heating elements hide half-waves in parallel to one another. Task and solution

The invention has for its object to provide a control method for a partial area of a heating field consisting of individual heating elements, it should be possible with the method to achieve a uniform and specifically determinable power output over this partial area.

This problem is solved by a control method with the features of claim 1. Advantageous and preferred embodiments tion of the invention are specified in the further claims and are explained in more detail below. The wording of the claims is made the content of the description by express reference.

According to the invention the drive method for a portion of a heating surface having n _H eizfi _ä c _h e heating elements, wherein the partial region riBereich heating elements having discrete power levels, in six steps, of which the steps 1 to 4 are preliminarily and steps 5 and 6 continuously during of the heating process:

1. Determining a predetermined target power P _S oiι,

2. Calculate a maximum number of heating elements which, at the highest power level, do not together exceed the target power Psoii,

3. calculating the power difference Prviuster between the desired power P _o ii and one of the determined number of non of heating at the highest power level output power Po _n, 4. Setting n _M us _t he patterns of clocks with optionally different power levels, which in means lead to a power output of Pfviuster, wherein n _M is the maximum model (n _be-rich non),

5. Operation of non heating elements with the highest power level, n _M model heating elements in the pattern operation, that is with the respectively predetermined by the respective pattern power stage, and (n _Be reic _h - non-n _M u _s t _e r) heating elements without power output and

6. permanent change of the assignment of the function specified under 5. to the actual heating elements in a rotation process, whereby the defined patterns run through and are started again after completion. - ~

The heating surface can be both a heating surface for only one cooking vessel, which has several heating elements, so that the heated surface can be adapted to the size of the cooking vessel, as well as a heating surface for one or more cooking vessels, in which the cooking vessels can be arranged anywhere on the heating surface and in which the heating surface is divided into a plurality of elements that can be controlled separately from each other, so that only the heating elements are specifically supplied with energy that are arranged so that they stand on the heating surface can heat. In the sub-region, it may also be the entire heating surface with all n _H eiz _f i e _Äch act heating elements. The heating elements have discrete power levels that determine the amount of power they can output. In the smallest case there are two power levels, with 0% of the maximum power being output in one of the power levels and 100% of the maximum power being output in the other of the power levels. A heating element with a total of four discrete power levels could, for example, give 0%, 33.3%, 66.6% and 100% of its maximum power. The power to be determined in the first step of the method can be set directly by an operator or can also come from a control device which, for example, specifies the target power Ps _o ii on the basis of an automatic cooking program or a manual input with specific power profiles. The target power Psoii should not exceed the maximum power that can be output by all heating elements in the sub-area at the highest power level. In the second step, the number of heating elements is determined which, when operating at the highest power level, together come as close as possible to the target power P _Sθ ιι without exceeding it. The number of these heaters is non in the least case, zero, even the power output provided a heating element at maximum power, the target performance would exceed Psoii, and in the highest case nβereic _h, all the heating elements of the subregion with the highest power level if the target performance overall Psoii reach or the target power Psoii is above the maximum power that can be output by all heating elements in the sub-area.

In the third method step, it is determined how large the difference between the power P _{0n that can} be output by n ₀ n heating elements at the highest power _level and the desired power Psoii is. This power must be applied by one or more heating elements that cannot be operated continuously at the highest power level in order not to exceed the power Ps _o ii. If these power difference Prvius he _t is not zero, in the fourth method step, a number n _M u _s t r _e patterns of clocks of different power levels composed that can achieve these power difference P _M model. The patterns consist of any number of cycles of the same length, each of which is carried out at a specific performance level. The respective average power outputs of these patterns must sums the power difference P _M u _ste r arise. Due to the fixed number of cycles and the discrete power levels of the heating elements, it is not absolutely possible to achieve the PMuster power exactly. By increasing the number of cycles per pattern and increasing the number of discrete power levels, a more precise adjustment can be made possible, although this is normally not necessary. Even if the method allows, in principle, more than one pattern of cycles with different power levels to be used, preferably only one pattern should be defined, which runs on a heating element in the pattern mode. The number of samples shall be the number n _Be reaching the heating elements in the partial area minus the number of non heating elements that are operated at each of maximum power, not exceed.

Within these first four process steps, the number of heating elements that are operated at the highest power level, the number of heating elements in sample mode, and the pattern itself are determined. In the actual operation of the heating elements of the sub-area, the functions "power output at the highest power level", "power output according to a defined model" and "no power output" are assigned to the heating elements of the sub-area in a rotating manner if there is at least one heating element of each function, each heating element in the sub-area is also assigned to each function in rotation. After a fixed number of cycles, preferably after each cycle, the function assignment continues to rotate. As a result, all heating elements, over the duration the sample averaged, operated with approximately the same output, however, despite the discrete power levels of the heating elements, it is only ever necessary to control an adapted power output with respect to one heating element - the heating element that is currently being operated in the sample mode elements are operated without a power output or at the highest power level. The heating elements are preferably induction heating elements.

In a development of the method the number NMU is _t he the one pattern. This represents a particularly expedient embodiment of the method, since only one heating element is in sample operation. As a result, the remaining heating elements are operated at full power or are not in operation.

In a development of the method, the discrete power levels of the heating elements are generated by omitting individual half-waves of a cycle in the AC supply.

With this form of control, a number of half-waves, which is preferably even, are combined to form one cycle. By omitting a different number of half-waves within one The various discrete power levels can be achieved with such a clock. If standards or regulations stipulate that the negative and positive half-waves must be balanced within a certain number of half-waves, the number of power levels is reduced. In the case of cycles with six half-waves each, in which the number of negative and positive half-waves per cycle must be balanced, the four alternatives for the cycle with zero half-waves, with two half-waves, with four half-waves or with six half-waves result. Such a cycle can therefore assume the discrete power levels "no power output", "one third of the maximum power", "two thirds of the maximum power" and "maximum power". Particularly advantageous when using the control method according to the invention with clock cycles which differ in their power output due to the omission of half-waves is the minimization of fluctuations in the power consumption of the heating field, since in the partial areas only the heating elements operated with samples, preferably therefore only one heating element, alternately partially omitting half-waves and partially not omitting.

In a further development of the invention, the pattern is composed exclusively of cycles of two different power levels, with no power being output at one power level and the other power level being the next higher power level to the power difference P _M.

In such a method, the number of cycles in which an intermediate stage between no power output and the maximum power output is applied is reduced as far as possible. This is advantageous in the sense of simple control of the heating elements.

In another development of the method, the pattern is composed exclusively of cycles of two different performance levels, where the one power level is the next higher power level to the power difference pattern and the other power level is the next lower power level to the power difference PMuster. In this way, a relatively balanced output is achieved.

In a development of the method, the cycles of different performance levels are evenly distributed in the pattern. The even distribution of the cycles of different performance levels means that the output is very even within the duration of a passage through the sample.

In a further development of the method, the cycles are arranged in blocks of the same power levels and arranged in the pattern. This is the simplest method for distributing the clocks of different power levels within the pattern. With regard to a control device for such a method, this offers the advantage that the control device can specify cycles of a higher power level until the required power P _M us _t er within the pattern has been reached, and then only until the end of the run through the pattern to specify cycles without output.

In the invention, the number of clocks of the pattern is a prime number which is greater than the number of heating elements neereic _h of the portion is preferably greater than the number of heating elements nHeizfiäche the entire heating surface.

Such a determination of the number of cycles of the pattern ensures that no irregular distribution occurs when the functions are assigned to the heating elements in a rotating manner. Such an irregular distribution could result in a heating element being in and out of the pattern operation again and again at the same cycles of the pattern the consequence would be the inhomogeneous output of the sub-area. By selecting such a prime number as the number of cycles of the pattern, a different heating element as the first heating element has the function "output according to pattern" with each pass through the pattern. It is particularly expedient if the number of cycles of the pattern is greater than the number of is heaters n _H eizfi _ä c _h e of the entire heating surface. such a method does not require that depends on the number nBereic of the heating elements in the partial area _h are each a prime number are determined must instead. is always a uniquely determined for the entire heating surface prime This can be permanently programmed in a control unit to carry out the method.

The object on which the method is based can also be achieved by a device with the features of claim 9, preferably a control device, for controlling heating elements of a hob, as well as by a hob with the features of claim 10, this device being designed to do the described Execute procedure.

Such a device can be part of a hob together with several heating elements. In a further development of such a hob, induction devices are preferably provided as heating elements.

These and further features of preferred further development of the invention emerge from the claims and also from the description and the drawings, the individual features being realized individually or in groups in the form of sub-combinations in one embodiment of the invention and in other areas and can represent advantageous and protectable versions for which protection is claimed here. Brief description of the drawings

Embodiments of the invention are shown schematically in the drawings and are explained in more detail below. In the drawings show:

Fig. 1 is a schematic representation of the method, Fig. 2 is a plan view of a heating surface with two sub-areas in operation, Fig. 3 shows a pattern of 41 cycles, in which the power output is determined for each cycle for each of the three heating elements of the first sub-area 4 is a pattern of 41 cycles, in which the power output is determined for each cycle for one of the seven heating elements of the second sub-area,

5 shows three operating states of the first of the two regions in operation from FIG. 2, FIG. 6 seven operating states of the second of two regions in operation from FIG. 2 and FIG. 7 a representation of a complete pattern of 41 cycles, whereby for Each cycle shows how high the power output is and which of the heating elements is currently delivering maximum power, which of the heating elements is not performing power and which of the heating elements is delivering power in accordance with the sample specification.

Detailed description of the exemplary embodiments

1 shows a schematic representation of the method according to the invention. Input parameters of the process, the maxi- mum power PHeizeiement that can deliver a heating element in each case, the number of heating elements n _Ber verifiable that belong to the part to be heated range, and in the entire portion to be obtained power P _Sθ ιι- On the basis of these predetermined values, the number of non-heating elements is determined in a first step 10, which in operation does not just exceed the total target power Psoii during operation at full power PHeementement. In a subsequent step 12, the power Pon is calculated, the non this number of heating elements at full power P _H eizeiement in operation guaranteed. In the following step 14, the power difference jdoe is calculated, the target power and the power Po of Psoii no _n heating elements in each full power P _H eiz _e is iement between the total. In a next step 16, the n _M model pattern advertising set composed of bars of different power levels and, where appropriate, together provide the service jdoe average in their sum. The number of cycles per pattern nja _kt ePro pattern is fixed in the present case. Alternatively, it would, however, also possible for the number of cycles per sample nja teProMuster dependent on other values preferably, the number n _Be reic _h of the heating elements in the subregion, flexible set.

In phase 18 of operation, the heating elements are operated on the basis of the determined values and the defined pattern. The heating elements can basically perform one of three different functions. A number of heating elements are operated with maximum power. A number n of heating element patterns, which are preferably only one heating element, are operated with patterns defined in step 16. The remaining heating elements in the section do not deliver any power. The assignment of these functions to the actual heating elements changes permanently. The assignment is changed at short intervals, preferably at intervals of the time length of a cycle.

Fig. 2 shows a heating surface with a total of 38 heating elements. The maximum output of each heating element is 300 watts. Two sections 30, 32 of the heating surface are in operation. The partial area 30 consists of a total of three heating elements 30a, 30b, 30c. The target power of this partial area 30 is 360 watts. The second section 32 consists of a total of seven heating elements 32a, 32b, 32c, 32d, 32e, 32f, 32g. The target power of this second section 32 is 1350 watts.

In order to achieve the desired output of 360 watts in subarea 30, one heating element is operated with its maximum output of 300 watts and a second heating element is operated in sample mode, that is to say with a pattern of cycles of different power levels. This is such that it leads to a power output of approx. 60 watts over the length of a complete pass. A third heating element of section 30 is not needed to achieve the desired output of 360 watts. In the illustrated operating state of the partial area 30, the cross-hatched heating element 30b is operated with its maximum output of 300 watts, the single-hatched field 30a is operated with the pattern, and the heating element 30c has no power output.

In order to achieve the target power of 1350 watts with respect to the second partial area 32, a total of four heating elements are operated with their full power of 300 watts each and a further heating element is operated in the sample mode. Two heating elements of section 32 are not needed to achieve the target output of 1350 watts. In the operating state shown, the four fields 32a, 32e, 32f, 32g each output their maximum power. The heating element 32d is operated with the pattern. The two heating elements 32b, 32c do not output any power.

3 and 4 show the control patterns 34, 36 of the heating elements of the partial areas 30, 32 which are respectively in pattern operation. Since the entire heating surface has thirty-eight heating elements, the number of heating elements is

Bars per pattern 41 selected as the next prime number. The sample accordingly consist of forty-one cycles, each cycle can assume one of four discrete power levels. The performance levels are 0%, 33.3%, 66.6% and 100% of the performance. Converted to absolute power, this means that the power levels are 0 watts, 100 watts, 200 watts and 300 watts.

The heating element operated with the sample in the first partial area 30 must provide the power difference between the target power 360 watts and that of the one heating element operated at maximum power 300 watts. Since the power difference of 60 watts is still below the second of the discrete power levels of 100 watts, the pattern consists of clocks with 0 watts of power and 100 watts of power. The corresponding pattern 34 is shown in FIG. 3. It consists of 25 cycles with 100 watts of power and 16 cycles with 0 watts of power. The cycles of the same power are combined into blocks. The average power for the entire pattern is 60.97 watts. Based on the entire partial area 30, this results in an average power output of 360.97 watts over one pass of the pattern. This is only slightly above the target power of 360 watts for this subarea 30.

4 shows the pattern 36 of the heating element of the partial area 32 operated with a pattern. The power to be applied by this heating element of the partial area 32 is 150 watts. The next higher discrete power level delivers 200 watts. The pattern has 31 cycles with the discrete power level of 200 watts. In addition, the sample shows ten bars without output. As with the pattern of the first partial area 30, the pattern of the second partial area 32 is divided into blocks with clocks of the same line level. The power emitted by the replaceable heating element in this sample averages 151, 21 watts over one pass of the sample. Together with the four heating elements of the second sub-area 32, which at full power operated, the total output is 1351, 21 watts. The target power of the second partial area 32 is thus exceeded by only a little more than one watt.

5 and 6 show the different assignments of the functions of the heating elements to the different heating elements for the first partial area 30 and the second partial area 32. The cross-hatched heating elements are each the heating elements which are operated at maximum power. The simply hatched heating elements are the heating elements on which the respective pattern of the partial area runs.

5 shows three operating states of the first subarea 30. In the operating state 40, the heating element 30b is operated at full power, the heating element 30a is operated with the pattern 34 and the heating element 30c is not operated. After a specified time, preferably after a cycle of the pattern, the heating elements change their assignment to the functions, so that the second operating state 42 is established. This is followed by the third operating state 44 after the same time period. Subsequently, the first operating state 40 is continued again. It can be seen that in this way each of the heating elements has assumed each function once. The choice of the prime number 41 as the number of cycles of the pattern ensures that the same heating element does not begin to carry out the pattern each time the pattern is passed. In the event that the pattern started on heating element 30a on the first pass, it will start on heating element 30b on the second pass. This ensures that the heating elements emit power very evenly.

6 shows the assignment of the functions to the heating elements for the second partial area 32. The second partial area 32 has a total of seven different phases 50, 52, 54, 56, 58, 60, 62. In the phase 50, the heating element 32g represents the heating element that outputs power according to the pattern 36. The four heating elements 32b, 32c, 32d, 32e are operated at full power. The two heating elements 32a, 32f are operated without power. With each change from one phase to the next, the assignment changes, so that after seven phase changes, each heating element was operated a total of four times at full power, twice without power and once according to the pattern from FIG. 5. This results in a uniform power output for the entire second partial area 32.

7 shows a complete run through the pattern for the first partial region 30. For each of the 41 cycles, it is shown which heating element is in alternating operation for the respective cycle and thus carries out a power output according to the sample. The pattern begins with phase 70, in which the heating element 30a represents the alternating heating element. From there, the assignment of the functions to the heating elements of the subarea 30 is changed with each cycle. During the first 25 cycles, the power output of the removable heating element is 100 watts. In the subsequent 16 cycles, from phase 95 to phase 110, the power output of the removable heating element is 0 watts in each case. So after a complete run of the pattern,

1. that the heating element 30a was operated with 300 watts for 14 cycles, with 100 watts for 9 cycles and with 0 watts for 18 cycles, that is to say with 124.39 watts on average,

2. that the heating element 30b was operated for 14 cycles with 300 watts, for 8 cycles with 100 watts and for 19 cycles with 0 watts, ie with an average of 121.95 watts and 3. that the heating element 30c was operated for 13 cycles with 300 watts, for 8 cycles with 100 watts and for 20 cycles with 0 watts, ie on average with 114.63 watts.

The fact that the heating element 30b would start to carry out the pattern the next time through the pattern means that these performance differences are compensated for during longer operation.

Claims

claims

1. A driving method of a partial area (30, 32) a heating surface with nHeizfiäc _h e heating elements, wherein the partial region (30, 32) n _R ange heating elements (30a, 30b, 30c, 32a, 32b, 32c, 32d, 32e, 32f, 32g) with discrete power levels, it being possible with the method to achieve a power output that is uniform and specifically determinable over the sub-area (30, 32), with the preparatory method steps: 1. determining a predetermined target power Ps _o ii, 2 . calculating a non highest number of heating elements do not exceed the highest at each power level together, the target power Psoii, 3. calculating the power difference P _M model between the target power P _o ii and one of the determined number of heating elements at highest non Power level output power Po _n , 4. Definition of n-pattern samples (34, 36) of cycles with possibly different power levels, which on average lead to a power output of P _M u _s t lead _e r, where n _M u _s t _e r max (n _R ange-non) is, and the steps in the execution: 5th operation of non heating elements with the highest power level, n model heating elements with the respective pattern given power level and (he n _{Ber-verifiable} non- n _M u _st) heating elements without power output and the sixth permanent change of assignment of under 5 specified functions to the actual heating elements (30a, 30b, 30c, 32a, 32b, 32c, 32d , 32e, 32f, 32g) in a rotation process, the defined patterns (34, 36) going through and starting again each time after completion. _ _

2. The method according to claim 1, characterized in that the number of patterns n pattern is one.

3. The method according to claim 1 or 2, characterized in that the discrete power levels of the heating elements are generated by omitting individual half-waves of a cycle in the AC supply.

4. The method according to any one of claims 1 to 3, characterized in that the pattern (34, 36) is composed exclusively of clocks of two different power levels, with no power being output at one power level and the other power level being the to the power difference P _M ust _e r next higher power level.

5. The method according to any one of claims 1 to 3, characterized in that the pattern is composed exclusively of clocks of two different power levels, the one power level being the next higher power level to the power difference PMuster and the other power level being the power level difference P _M is u r _ste next lower power level.

6. The method according to any one of the preceding claims, characterized in that the cycles of different power levels are evenly distributed in the pattern.

Method according to one of claims 1 to 5, characterized in that the clocks are combined in blocks of the same power levels in the pattern (34, 36).

8. The method according to any one of the preceding claims, characterized in that the number of cycles of the pattern (34, 36) is a prime number which is greater than the number of heating elements (30a, 30b, 30c, 32a, 32b, 32c, 32d, 32e, 32f, 32g) n _Ber eic _h of the portion (30, 32), wherein preferably the number of bars of the pattern (34, 36) is greater than the number of heating elements nHeiztiäc _h e is the entire heating surface.

9. Device, preferably a control unit, for controlling heating elements (30a, 30b, 30c, 32a, 32b, 32c, 32d, 32e, 32f, 32g), in particular for controlling heating elements (30a, 30b, 30c, 32a, 32b, 32c , 32d, 32e, 32f, 32g) of a hob as a heating surface, characterized in that it is designed to carry out the method according to one of claims 1 to 8.

10. Hob as a heating surface with a plurality of heating elements (30a, 30b, 30c, 32a, 32b, 32c, 32d, 32e, 32f, 32g) and a control device for controlling the heating elements (30a, 30b, 30c, 32a, 32b, 32c, 32d , 32e, 32f, 32g), characterized in that the control device is a device according to claim 9.

1 1. hob according to claim 10, characterized in that the heating elements (30a, 30b, 30c, 32a, 32b, 32c, 32d, 32e, 32f,

32g) are induction devices.