CN101848566B - Heating device - Google Patents

Abstract

The invention provides a heating device. The heating device comprises a first induction coil, a second induction coil, a control panel, a power supply unit and a control unit, wherein the control panel is used to adjust the heating energy of the first induction coil and the second induction coil to generate an adjusting signal; the power supply unit is connected with the first induction coil and the second induction coil to separately provide a first power source and a second power source for the first and second induction coils; the control unit is connected with the control panel and the power supply unit to generate control signals according to the adjusting signal to control the first and second power sources of the power supply unit; during a first time interval, the power supply unit provides electrical energy for the first and second induction coils at the same time, the frequency difference of the first power source and the second power source is more than 15KHz or less than 1KHz; and during a second time interval, the power supply unit ceases to provide electrical energy for the first or second induction coil. The heating device can not generate noises of which volume is uncontrollable, and the induction heating quantity of the food container can be adjusted by the user.

Description

Heater

Technical field

The present invention relates to a kind of heater, relate in particular to a kind of heater that can heat a plurality of food material containers simultaneously.

Background technology

In recent years along with the progress of science and technology, the heater of people's culinary art no longer only has single kind to select, except the heater that utilizes the heating of gas fuel, the multiple choices such as microwave oven, infrared-type baking box and electric-heating heating furnace are more arranged, these heaters miscellaneous respectively have its pluses and minuses, can be applicable to respectively the occasion of culinary art and the culinary art of various different food materials, to satisfy the different users that require.

The traditional heating device utilizes induction coil to make the cook utensil heating, supplies power to the electric weight size control of induction coil to the heat that adds of cook utensil by adjustment again.In order simultaneously two cook utensils to be heated, have more a plurality of induction coils realizing simultaneously a plurality of cook utensils heating in some heaters, and supply power to induction coil electric weight size separately by adjustment and make cook utensil can have different heating-up temperatures.

Yet the traditional heating device can make to have difference on the frequency between the induction coil and produce the noise that the people can hear frequency range, and then make the traditional heating device produce noise when adjusting respectively the electric weight size supply power to induction coil.Because traditional heater can produce noise when operation, therefore except can't being applicable to quiet occasion, more can cause the user can't be wholwe-hearted when culinary art, the quality of impact culinary art.Moreover; noise and revocable volume; the material of employed food materials, food materials consumption, cook utensil size and cook utensil is different and change in the time of can be along with the user cooking; cause the user to think heater operation exception or fault by mistake and send and repair, make heater manufacturer increase the unnecessary cost of overhaul.

Summary of the invention

Therefore, how to develop a kind of heater that improves above-mentioned known technology defective, be in fact the present problem in the urgent need to address of correlative technology field.

The object of the present invention is to provide a kind of heater, when using a plurality of induction coils respectively to many food material containers induction heating, heater can not produce the noise of uncontrollable volume, simultaneously, more can adjust respectively induction coil to separately food material container induction heating add heat or heating-up temperature, make the heat that adds of food material container induction heating separately be the heat that adds of user's wish adjustment.

For reaching above-mentioned purpose, of the present invention one than the broad sense execution mode for a kind of heater is provided, in order to at least one food material container induction heating, this heater comprises: the first induction coil; The second induction coil; One control panel, signal is adjusted in corresponding generation one with the heat energy size of this second induction coil in order to adjust this first induction coil; One Power supply unit is connected in this first induction coil and this second induction coil, in order to provide respectively one first power supply and a second source to this first induction coil and this second induction coil; And a control unit, be connected in this control panel and this Power supply unit, in order to produce this first power supply and this second source that control signal is controlled this Power supply unit according to this adjustment signal.Wherein, provide simultaneously electric energy to the first induction coil and the second induction coil in interval control unit control of very first time Power supply unit, and the difference on the frequency of the first power supply and second source is greater than 15 KHz or less than 1 KHz, and stop to provide electric energy to the first induction coil or the second induction coil in the second time interval control unit control Power supply unit, and this control unit is before this very first time interval and this second time interval, detect first a heat characteristic parameter value, this heat characteristic parameter value is one first minimum frequency value, one second minimum frequency value, one first minimal power values and one second minimal power values.

For reaching above-mentioned purpose, of the present invention another than the broad sense execution mode for a kind of heater is provided, in order to at least one food material container induction heating, this heater comprises: the first induction coil; The second induction coil; Control panel, signal is adjusted in corresponding generation with the heat energy size of the second induction coil in order to adjust the first induction coil; The Power supply unit is connected in the first induction coil and the second induction coil, in order to the first power supply and second source to the first induction coil and the second induction coil to be provided respectively; And control unit, be connected in control panel and Power supply unit, in order to produce the first power supply and the second source that control signal is controlled the Power supply unit according to adjusting signal.Wherein, interval and the 3rd time interval in the very first time, the difference on the frequency of the first power supply and second source is greater than 15 KHz, and in the second time interval, the difference on the frequency of the first power supply and second source is less than 1 KHz, and this control unit is before this very first time interval, this second time interval and the 3rd time interval, detect first a heat characteristic parameter value, this heat characteristic parameter value is one first minimum frequency value, one second minimum frequency value, one first minimal power values and one second minimal power values.

The present invention can not produce the noise of uncontrollable volume, can divide simultaneously other adjust induction coil to the food material container induction heating add heat or heating-up temperature, make the heat that adds of food material container induction heating be the heat that adds of user's wish adjustment.

Description of drawings

Fig. 1: be the heater schematic diagram of preferred embodiment of the present invention.

Fig. 2 A: be the first frequency of the heater of preferred embodiment of the present invention and the frequency sequential schematic diagram of second frequency.

Fig. 2 B: be the first frequency of the heater of another preferred embodiment of the present invention and the frequency sequential schematic diagram of second frequency.

Fig. 2 C: be the first frequency of the heater of another preferred embodiment of the present invention and the frequency sequential schematic diagram of second frequency.

Fig. 2 D: be the first frequency of the heater of another preferred embodiment of the present invention and the frequency sequential schematic diagram of second frequency.

Fig. 3 A: be the first frequency of the heater of another preferred embodiment of the present invention and the frequency sequential schematic diagram of second frequency.

Fig. 3 B: be the first frequency of the heater of another preferred embodiment of the present invention and the frequency sequential schematic diagram of second frequency.

Description of reference numerals in the above-mentioned accompanying drawing is as follows:

Embodiment

Some exemplary embodiments that embody feature ﹠ benefits of the present invention will be described in detail in the explanation of back segment.Be understood that the present invention can have in different modes various variations, its neither departing from the scope of the present invention, and explanation wherein and the accompanying drawing usefulness that ought explain in itself, but not in order to limit the present invention.

See also Fig. 1, it is for the heater schematic diagram of preferred embodiment of the present invention.As shown in Figure 1, heater 1 comprises the first induction coil 11a, the second induction coil 11b, control panel 12, Power supply unit 13 and control unit 14, and by the first induction coil 11a and the second induction coil 11b respectively to the first food material container 2a and the second food material container 2b induction heating.Wherein, the first induction coil 11a and the second induction coil 11b are connected to the first power output end and the second source output of Power supply unit 13.

Control panel 12 is connected with control unit 14, and is arranged at heater 1 outside, and is big or small in order to the heat energy of adjusting the first induction coil 11a and the second induction coil 11b, and corresponding the generation adjusted signal K ₁Be sent to control unit 14.Power supply unit 13 is connected to the first induction coil 11a, the second induction coil 11b and control unit 14, in order to the first power supply V to be provided respectively ₁With second source V ₂To the first induction coil 11a and the second induction coil 11b, make the first induction coil 11a and the second induction coil 11b the operation and respectively to the first food material container 2a and the second food material container 2b induction heating.Control unit 14 is connected in control panel 12 and Power supply unit 13, in order to according to adjusting signal K ₁Produce control signal K ₂And control Power supply unit 13 exports the electric weight size of the first induction coil 11a and the second induction coil 11b to.In the present embodiment, the control unit 14 of heater 1 of the present invention can be but not be defined as pulse frequency modulated controller (pulse frequency modulation controller, PFM controller) or digital signal processor (digital signal processor, DSP).

In the present embodiment, Power supply unit 13 is for example AC-AC change-over circuit, and wherein, the electric weight size that Power supply unit 13 exports the first induction coil 11a to is inversely proportional to the first power supply V ₁First frequency f ₁The frequency values of (not shown), similarly, the electric weight size that Power supply unit 13 exports the second induction coil 11b to is inversely proportional to second source V ₂Second frequency f ₂The frequency values of (not shown).In the present embodiment, Power supply unit 13 conversion input power V _InAlternating voltage and frequency and produce respectively the first power supply V ₁With second source V ₂Be sent to the first induction coil 11a and the second induction coil 11b, wherein, Power supply unit 13 can be according to control signal K ₂Make the first power supply V ₁First frequency f ₁(not shown) and second source V ₂Second frequency f ₂(not shown) corresponding signal K that adjusts ₁Change, the electric weight that exports the first induction coil 11a and the second induction coil 11b with control Power supply unit 13 to is big or small, and then controls the first induction coil 11a and the second induction coil 11b and respectively the first food material container 2a and the second food material container 2b added the heat size.

In the present embodiment, control panel 12 comprises at least two touch-tone adjustment elements 121～122, in order to the heating-up temperature of adjusting 1 couple of the first food material container 2a of heater and the second food material container 2b or add heat, in certain embodiments, the adjustment element of control panel 12 more can use revolving adjustment element (not shown).When the user adjusted the temperature of wish heating or adds heat by the adjustment element 121～122 of control panel 12, control panel 12 can produce corresponding adjustment signal K ₁, and control unit 14 produces corresponding control signal K via calculating again after receiving adjustment signal K1 ₂, with first frequency f corresponding to control Power supply unit 13 outputs ₁(not shown) and second frequency f ₂(not shown).

The first induction coil 11a of heater 1 of the present invention and the second induction coil 11b can be separately to the first food material container 2a or the second food material container 2b induction heating, the first induction coil 11a and the second induction coil 11b also can be simultaneously to single larger food material container (not shown) induction heating, below will be take the first induction coil 11a and the respectively operation of the heater 1 of the present invention as demonstration example illustrates to the first food material container 2a and the second food material container 2b induction heating of the second induction coil 11b.

See also Fig. 2 A and cooperate Fig. 1, it is the first frequency of the heater of preferred embodiment of the present invention and the frequency sequential schematic diagram of second frequency.Shown in Fig. 2 A, in very first time t ₁Before, heater 1 does not heat operation, and Power supply unit 13 does not supply power to the first induction coil 11a and the second induction coil 11b, the first power supply V ₁With second source V ₂Be zero voltage value, so the first induction coil 11a and the second induction coil 11b do not heat operation.In very first time t ₁The time, the user opens heater 1, and the user sets respectively the first food material container 2a by control panel 12 and the second food material container 2b wants to add heat size or temperature.In the present embodiment, heater 1 set according to the user begin the heating operation before, i.e. very first time t ₁To the 3rd time t ₃Between, control unit 14 can detect first some heat characteristic parameter values, for example the first minimum frequency value f _Min1, the second minimum frequency value f _Min2, the first minimal power values P _Min1And the second minimal power values P _Min2, below will enumerate its detection method but not as limit.

In very first time t ₁To the second time t ₂Between, second frequency f ₂Be maintained the second maximum frequency values f _Max2, it is the second minimal power values P that correspondence makes the second induction coil 11b _Min2, and control unit 14 can be controlled Power supply unit 13 with first frequency f ₁Frequency values by the first maximum frequency values f _Max1Gradually be reduced to the first minimum frequency value f _Min1, to detect first frequency f ₁Be the first maximum frequency values f _Max1The time the first minimal power values P corresponding to the first induction coil 11a _Min1, and the first induction coil 11a is the first maximum power value P _Max1The time first frequency f ₁The first corresponding minimum frequency value f _Min1

Similarly, in the second time t ₂To the 3rd time t ₃Between, first frequency f ₁Be maintained the first maximum frequency values f _Max1, it is the first minimal power values P that correspondence makes the first induction coil 11a _Min1, and control unit 14 can control Power supply unit 13 with the frequency values of second frequency f2 by the second maximum frequency values f _Max2Gradually be reduced to the second minimum frequency value f _Min2, to detect second frequency f2 as the second maximum frequency values f _Max2The time the second minimal power values P corresponding to the second induction coil 11b _Min2, and the second induction coil 11b is the second maximum power value P _Max2The time second frequency f ₂The second corresponding minimum frequency value f _Min2In certain embodiments, at very first time t ₁To the second time t ₂Between, heater 1 can be set second source V ₂For zero voltage value (not shown) so that the second induction coil 11b is out of service, at the second time t ₂To the 3rd time t ₃Between, heater 1 can be set the first power supply V ₁For zero voltage value (not shown) makes the first induction coil 11a out of service.

In the 3rd time t ₃Heater 1 begins the heating operation afterwards, and the first induction coil 11a and the second induction coil 11b can be respectively to the first food material container 2a and the second food material container 2b induction heating.In interval T of the very first time _A1, except first frequency f ₁With second frequency f ₂Frequency values greater than outside people's audible sound pitch critical frequency, first frequency f ₁With second frequency f ₂Difference on the frequency more can be set as greater than people's audible sound pitch critical frequency or less than the low critical frequency of people's sub-audible sound, wherein, people's audible sound pitch critical frequency is about 15k～25k hertz (Hz), and the low critical frequency of people's sub-audible sound is about the 1k hertz.

In the present embodiment, in interval T of the very first time _A1The time, first frequency f ₁Be first frequency value f ₁₁, second frequency f ₂Be second frequency value f ₂₁, and first frequency value f ₁₁Less than second frequency value f ₂₁, be inversely proportional to respectively first frequency f owing to being sent to the power of the first induction coil 11a and the second induction coil 11b ₁And second frequency f ₂Frequency values, so the electric energy of Power supply unit 13 output mainly is sent to the first induction coil 11a, and by the first induction coil 11a to the first food material container 2a induction heating.

In the second time interval T _A2, the first power supply V ₁Be zero voltage value, the first induction coil 11a stops the first food material container 2a induction heating, at this moment, and second frequency f ₂Be the 4th frequency values f22 and greater than people's audible sound pitch critical frequency, because the first power supply V ₁Be zero voltage value, so Power supply unit 13 output electric energy all are sent to the second induction coil 11b, and pass through the second induction coil 11b to the second food material container 2b induction heating.Then, control unit 14 can repeat interval T of the above-mentioned very first time in control Power supply unit 13 _A1With the second time interval T _A2

In the present embodiment, heater 1 is in interval T of the very first time _A1, with first frequency f ₁With second frequency f ₂Difference on the frequency set greater than people's audible sound pitch critical frequency or less than the low critical frequency of people's sub-audible sound, heat simultaneously when moving, because of first frequency f although can effectively prevent the first induction coil 11a and the second induction coil 11b ₁With second frequency f ₂Difference on the frequency circle between the low critical frequency of people's sub-audible sound and people's audible sound pitch critical frequency, and produce the noise of uncontrollable volume, also so that Power supply unit 13 be sent to the electric weight size of the first induction coil 11a and the second induction coil 11b can't unit control.In other words, in interval T of the very first time _A1, control unit 14 can only be with first frequency f ₁Or second frequency f ₂One of them is main, makes the first induction coil 11a or the second induction coil 11b add heat size or temperature to add heat size or the temperature of the first food material container 2a or the second food material container 2b for what the user set.

In the present embodiment, in interval T of the very first time _A1, control unit 14 is with first frequency f ₁Be the whole first frequency value of homophony f ₁₁, and according to adjusting signal K ₁Control Power supply unit 13 produces corresponding first frequency f ₁, and then control the electric energy size that Power supply unit 13 exports the first induction coil 11a to, make the first induction coil 11a to the add heat of the first food material container 2a induction heating amount for the adjustment of user's wish.As for, second frequency f ₂In interval T of the very first time _A1Second frequency value f ₂₁, need to be greater than people's audible sound pitch critical frequency or less than the restriction adjustment of the low critical frequency of people's sub-audible sound according to difference on the frequency, so, second frequency value f ₂₁Can't make the second induction coil 11b that the heat size correct response that adds of the second food material container 2b induction heating is gone out the heat that adds of user's wish adjustment.

Yet, at second frequency f ₂Be the 4th frequency values f ₂₂The second time interval T _A2, because the first power supply V ₁Be zero voltage value, second frequency f ₂The 4th frequency values f ₂₂As long as just can not produce the noise of uncontrollable volume greater than people's audible sound pitch critical frequency, so, second frequency f ₂Be not subjected to that difference on the frequency need to greater than people's audible sound pitch critical frequency or less than the restriction of the low critical frequency of people's sub-audible sound, control unit 14 can be correct in adjusting signal K without restriction ₁Control Power supply unit 13 produces corresponding second frequency f2, and then the electric energy size correct response that makes Power supply unit 13 export the second induction coil 11b to goes out the heat that adds of user's wish adjustment.Continue, by repeating interval T of the very first time _A1With the second time interval T _A2, can realize correctly adjusting respectively the first induction coil 11a and the second induction coil 11b the first food material container 2a and the second food material container 2b added heat or temperature.

In the present embodiment, heater 1 is in interval T of the very first time _A1During with the second time interval Ta2, the first induction coil 11a and the second induction coil 11b be adding heat and can change the first food material container 2a and the second food material container 2b respectively, so use mean value calculation to add heat, wherein, the first induction coil 11a on average adds heat P to first of the first food material container 2a ₁Relational expression is:

$P_1=P_{11}\left(f_{11}\right)\·\frac{T_{a1}}{T_{a1}+T_{a2}}=P_{11}\left(f_{11}\right)\·\frac{T_{a1}}{T_a},$

Wherein, first adds heat P ₁₁Be the first induction coil 11a heat that adds to the first food material container 2a when interval Ta1 of the very first time, can be along with interval T of the very first time _A1Middle first frequency f ₁First frequency value f ₁₁And change, and heating cycle T _aBe interval T of the very first time _A1With the second time interval T _A2Addition.

The second induction coil 11b on average adds heat P to second of the second food material container 2b ₂Relational expression is:

$P_2=P_{21}\left(f_{21}\right)\·\frac{T_{a1}}{T_{a1}+T_{a2}}+P_{22}\left(f_{22}\right)\·\frac{T_{a2}}{T_{a1}+T_{a2}}=P_{21}\left(f_{21}\right)\·\frac{T_{a1}}{T_a}+P_{22}\left(f_{22}\right)\·\frac{T_{a2}}{T_a},$

Wherein, second adds heat P ₂₁Be that the second induction coil 11b is in interval T of the very first time _A1The time to the heat that adds of the second food material container 2b, can be along with interval T of the very first time _A1Middle second frequency f ₂Second frequency value f ₂₁And change, and the 4th adds heat P ₂₂Be that the second induction coil 11b is in the second time interval T _A2The time to the heat that adds of the second food material container 2b, can be along with the second time interval T _A2Middle second frequency f ₂The 4th frequency values f ₂₂And change.

By above-mentioned relational expression as can be known, first on average adds heat P ₁More can utilize and adjust interval T of the very first time _A1Time span make first on average to add heat P ₁Be the heat that adds of user's wish adjustment, similarly, second on average adds heat P ₂Also can utilize and adjust interval T of the very first time _A1Or the second time interval T _A2Time span make second on average to add heat P ₂The heat that adds for the adjustment of user's wish.Therefore, in interval T of the very first time _A1The time, although second frequency f ₂Second frequency value f ₂₁Be subject to first frequency f ₂First frequency value f ₁₁, can't make the second induction coil 11b that the heat size correct response that adds of the second food material container 2b induction heating is gone out the heat that adds of user's wish adjustment, but can be by adjusting respectively the second time interval T _A2Middle second frequency f ₂The 4th frequency values f ₂₂, interval T of the very first time _A1Or the second time interval T _A2Time span, make second on average to add heat P ₂The heat that adds for the adjustment of user's wish.

In addition, the first induction coil 11a is the first maximum power value P _Max1The time, first frequency f ₁The first corresponding minimum frequency value f _Min1Can change with material along with the container size of the first food material container 2a, and first frequency f ₁Be the first maximum frequency values f _Max1The time, the first corresponding minimal power values P _Min1Also can change with material along with the container size of the first food material container 2a.In like manner, the second induction coil 11b is the second maximum power value P _Max2The time, second frequency f ₂The second corresponding minimum frequency value f _Min2Can change with material along with the container size of the second food material container 2b, and second frequency f ₂Be the second maximum frequency values f _Max2The time, the second corresponding minimal power values P _Min2Also can change with material along with the container size of the second food material container 2b, therefore, the first minimum frequency value f _Min1, the second minimum frequency value f _Min2, the first minimal power values P _Min1, the second minimal power values P _Min2Non-is fixed value.

Yet, the calculation relational expression of the induction heating amount of the first induction coil 11a and the first minimum frequency value f _Min1And the first minimal power values P _Min1Relevant (be not shown in above-mentioned first and on average add heat P ₁Relational expression), the calculation relational expression of the induction heating amount of the second induction coil 11b and the second minimum frequency value f _Min2And the second minimal power values P _Min2Relevant (be not shown in above-mentioned second and on average add heat P ₂And control unit 14 utilization is adjusted signal K relational expression), ₁, the first minimum frequency value f _Min1, the first minimal power values P _Min1, the second minimum frequency value f _Min2And the second minimal power values P _Min2Calculate and produce control signal K ₂Therefore, if control unit 14 with the first minimum frequency value f _Min1, the first minimal power values P _Min1, the second minimum frequency value f _Min2And the second minimal power values P _Min2Be set as fixed value, meeting is so that control unit 14 there are errors in computation the poor and larger control signal K that produces error ₂, cause heater 1 can't correctly reach the heating-up temperature of wish adjustment or add heat.

Because the control unit 14 of heater 1 of the present invention can detect first the first correct minimum frequency value f when bringing into operation _Min1, the first minimal power values P _Min1, the second minimum frequency value f _Min2And the second minimal power values P _Min2, and control unit 14 is in calculating interval T of the very first time _A1, the second time interval T _A2, first add heat P ₁₁, second add heat P ₂₁And the 4th add heat P ₂₂The time, use the first correct minimum frequency value f _Min1, the first minimal power values P _Min1, the second minimum frequency value f _Min2And the second minimal power values P _Min2Correctly calculate and the corresponding control signal K that does not have error amount that produces ₂, therefore, the problem that heater 1 can't correctly reach the heating-up temperature of wish adjustment or add heat can not occur in heater 1 of the present invention.

See also Fig. 2 B and cooperate Fig. 1 and Fig. 2 A, it is the first frequency of the heater of another preferred embodiment of the present invention and the frequency sequential schematic diagram of second frequency.Fig. 2 B is similar in appearance to Fig. 2 A, and Fig. 2 B and Fig. 2 A difference are among Fig. 2 B at interval T of the very first time _A1The time, control unit 14 is with second frequency f ₂Be the whole second frequency value of homophony f ₂₁Make the second induction coil 11b add heat size or temperature to add heat size or the temperature of the second food material container 2b for what the user set, need to adjust first frequency f greater than people's audible sound pitch critical frequency or less than the restriction of the low critical frequency of people's sub-audible sound according to difference on the frequency again ₁First frequency value f ₁₁, and at the second time interval T _A2, second source V ₂Be zero voltage value, the second induction coil 11b stops the second food material container 2b induction heating, at this moment, and first frequency f ₁Be the 3rd frequency values f ₁₂And greater than people's audible sound pitch critical frequency.Similarly, because second source V ₂Be zero voltage value, so Power supply unit 13 output electric energy all are sent to the first induction coil 11a, and pass through the first induction coil 11a to the first food material container 2a induction heating.Continue, control unit 14 can repeat interval T of the very first time among Fig. 2 B in control Power supply unit 13 _A1With the second time interval T _A2

In the present embodiment, the first induction coil 11a on average adds heat P1 relational expression to first of the first food material container 2a and is:

$P_1=P_{11}\left(f_{11}\right)\·\frac{T_{a1}}{T_a}+P_{12}\left(f_{12}\right)\·\frac{T_{a2}}{T_a},$

Wherein, first adds heat P ₁₁Be that the first induction coil 11a is in interval T of the very first time _A1The time to the heat that adds of the first food material container 2a, can be along with interval T of the very first time _A1Middle first frequency f ₁First frequency value f ₁₁And change, and the 3rd adds heat P ₁₂Be that the first induction coil 11a is in the second time interval T _A2The time to the heat that adds of the first food material container 2a, can be along with the second time interval T _A2Middle first frequency f ₁The 3rd frequency values f ₁₂And change.

The second induction coil 11b on average adds heat P to second of the second food material container 2b ₂Relational expression is:

$P_2=P_{21}\left(f_{21}\right)\·\frac{T_{a1}}{T_a},$

Wherein, second adds heat P ₂₁Be that the second induction coil 11b is in interval T of the very first time _A1The time to the heat that adds of the second food material container 2b, can be along with interval T of the very first time _A1Middle second frequency f ₂Second frequency value f ₂₁And change.

See also Fig. 2 C and cooperate Fig. 1, Fig. 2 A and Fig. 2 B, it is the first frequency of the heater of another preferred embodiment of the present invention and the frequency sequential schematic diagram of second frequency.Fig. 2 C is different from Fig. 2 A and Fig. 2 B part and is among Fig. 2 C T heating cycle _aExcept interval T of the very first time _A1With the second time interval T _A2More comprise the 3rd time interval T outward, _A3With the 4th time interval T _A4Wherein, interval T of the very first time of Fig. 2 C _A1With the second time interval T _A2Be same as the interval T of the very first time of Fig. 2 A _A1With the second time interval T _A2, control unit 14 is same first with first frequency f ₁Be the whole first frequency value of homophony f ₁₁, need to adjust second frequency f greater than people's audible sound pitch critical frequency or less than the restriction of the low critical frequency of people's sub-audible sound according to difference on the frequency again ₂Second frequency value f ₂₁In the same manner, among Fig. 2 C at the second time interval T _A2, the first power supply V ₁Be zero voltage value, the first induction coil 11a stops the first food material container 2a induction heating, and second frequency f ₂Be that the 4th frequency values f22 is also greater than people's audible sound pitch critical frequency.

As for, the 3rd time interval T of Fig. 2 C _A3With the 4th time interval T _A4Then similar in appearance to interval T of the very first time of Fig. 2 B _A1With the second time interval T _A2Shown in Fig. 2 C, in the 3rd time interval T _A3, control unit 14 is first with second frequency f ₂Be whole the 6th frequency values f of homophony ₂₃, need to adjust first frequency f greater than people's audible sound pitch critical frequency or less than the restriction of the low critical frequency of people's sub-audible sound according to difference on the frequency again ₁The 5th frequency values f ₁₃Similarly, among Fig. 2 C at the 4th time interval T _A4, second source V ₂Be zero voltage value, the second induction coil 11b stops the second food material container 2b induction heating, and first frequency f ₁Be the 7th frequency values f ₁₄Also greater than people's audible sound pitch critical frequency.

In the present embodiment, control unit 14 is prior to interval T of the very first time _A1With first frequency f ₁Be the whole first frequency value of homophony f ₁₁, again in the 3rd time interval T _A3Exchange is with second frequency f ₂Be whole the 6th frequency values f of homophony ₂₃, and in the second time interval T _A2Set the first power supply V ₁Be zero voltage value, and with second frequency f ₂The 4th corresponding frequency values f ₂₂Setting is greater than people's audible sound pitch critical frequency, more in the 4th time interval T _A4Set second source V ₂Be zero voltage value, and with first frequency f ₁The 7th corresponding frequency values f ₁₄Setting is greater than people's audible sound pitch critical frequency.

See also Fig. 2 D and cooperate Fig. 1 and Fig. 2 C, it is the first frequency of the heater of another preferred embodiment of the present invention and the frequency sequential schematic diagram of second frequency.Fig. 2 D is opposite with Fig. 2 C, and in Fig. 2 D, control unit 14 is prior to interval T of the very first time _A1With second frequency f ₂Be the whole second frequency value of homophony f ₂₁, again in the 3rd time interval T _A3Exchange is with first frequency f ₁Be whole the 5th frequency values f of homophony ₁₃, and in the second time interval T _A2Set second source V ₂Be zero voltage value, and with first frequency f ₁The 3rd corresponding frequency values f ₁₂Setting is greater than people's audible sound pitch critical frequency, more in the 4th time interval T _A4Set the first power supply V ₁Be zero voltage value, and with second frequency f ₂The 8th corresponding frequency values f ₂₄Setting is greater than people's audible sound pitch critical frequency.

In Fig. 2 C and Fig. 2 D, control unit 14 can be respectively by adjusting interval T of the very first time _A1, the second time interval T _A2, the 3rd time interval T _A3, the 4th time interval T _A4, first frequency value f ₁₁, second frequency value f ₂₁, the 3rd frequency values f ₁₂, the 4th frequency values f ₂₂, the 5th frequency values f ₁₃, the 6th frequency values f ₂₃, the 7th frequency values f ₁₄And/or the 8th frequency values f ₂₄Deng operational parameter value, make the first food material container 2a and the first food material container 2a add that heat or temperature level equal respectively the adjustment of user's wish add heat or temperature level, owing to can adjust more operational parameter values, therefore, control unit 14 can more easily make the first food material container 2a and the first food material container 2a add that heat or temperature level equal respectively the adjustment of user's wish add heat or temperature level.

See also Fig. 3 A and cooperate Fig. 1, it is the first frequency of the heater of another preferred embodiment of the present invention and the frequency sequential schematic diagram of second frequency.As shown in Figure 3A, in very first time t ₁Before, heater 1 does not heat operation, in very first time t ₁To the 3rd time t ₃Between, control unit 14 can detect first some heat characteristic parameter values, and its operational mode is same as above not to be repeated them here.In the present embodiment, heating cycle T _aComprise interval T of the very first time _A1, the second time interval T _A2And the 3rd time interval T _A3, in T heating cycle _aMiddle first frequency f ₁With second frequency f ₂Equally greater than people's audible sound pitch critical frequency, and in interval T of the very first time _A1With the 3rd time interval T _A3, first frequency f ₁With second frequency f ₂Difference on the frequency can be set as greater than people's audible sound pitch critical frequency, in the second time interval T _A2The time, first frequency f ₁With second frequency f ₂Difference on the frequency then be set as less than the low critical frequency of people's sub-audible sound.Wherein, first frequency f ₁With second frequency f ₂In the second time interval T _A2The time be respectively the first high frequency values f _1HWith the second high frequency values f _2H, and in interval T of the very first time _A1Or the 3rd time interval T _A3One of them can correspond to the first low frequency value f _1LOr the second low frequency value f _2L

In other words, if first frequency f ₁In interval T of the very first time _A1Be the first low frequency value f _1L, first frequency f then ₁In the 3rd time interval T _A3Can be the first high frequency values f _1HIf, first frequency f ₁In interval T of the very first time _A1Be the first high frequency values f _1H, first frequency f then ₁In the 3rd time interval T _A3Can be the first low frequency value f _1LIn like manner, if second frequency f ₂In interval T of the very first time _A1Be the second low frequency value f _2L, second frequency f then ₂In the 3rd time interval T _A3Can be the second high frequency values f _2HIf, second frequency f ₂In interval T of the very first time _A1Be the second high frequency values f _2H, second frequency f then ₂In the 3rd time interval T _A3Can be the second low frequency value f _2L

In the embodiment of Fig. 3 A, first frequency f ₁In interval T of the very first time _A1Be the first low frequency value f _1L, first frequency f ₁In the 3rd time interval T _A3Be the first high frequency values f _1H, and second frequency f ₂In interval T of the very first time _A1Be the second high frequency values f _2H, second frequency f ₂In the 3rd time interval T _A3Be the second low frequency value f _2LThe first induction coil 11a on average adds heat P to first of the first food material container 2a ₁Relational expression is:

$P_1={\mathrm{<figure-callout\; id="1L"\; label="P"\; filenames="H2009101288867E00071.png"\; state="\{\{state\}\}">P</figure-callout>}}_{1L}\left({\mathrm{<figure-callout\; id="1L"\; label="f"\; filenames="H2009101288867E00071.png"\; state="\{\{state\}\}">f</figure-callout>}}_{1L}\right)\&CenterDot;\frac{T_{a1}}{T_a}+P_{1H}\left(f_{1H}\right)\&CenterDot;\frac{T_{a2}+T_{a3}}{T_a},$

Wherein, the first low frequency adds heat P _1LBe that the first induction coil 11a is the first low frequency value f _1LThe time to the heat that adds of the first food material container 2a, and the first high-frequency heating amount P _1HBe that the first induction coil 11a is the first high frequency values f _1HThe time to the heat that adds of the first food material container 2a.

As for, the second induction coil 11b on average adds heat P to second of the second food material container 2b ₂Relational expression is:

$P_2=P_{2L}\left(f_{2L}\right)\&CenterDot;\frac{T_{a3}}{T_a}+P_{2H}\left(f_{2H}\right)\&CenterDot;\frac{T_{a1}+T_{a2}}{T_a},$

Wherein, the second low frequency adds heat P _2LBe that the second induction coil 11b is the second low frequency value f _2LThe time to the heat that adds of the second food material container 2b, and the second high-frequency heating amount P _2HBe that the second induction coil 11b is the second high frequency values f _2HThe time to the heat that adds of the second food material container 2b.

In the present embodiment, in interval T of the very first time _A1The time, control unit 14 can be with first frequency f ₁Be whole the first low frequency value f of homophony _1L, and according to adjusting signal K ₁Control Power supply unit 13 produces corresponding first frequency f ₁, make the first induction coil 11a to the add heat of the first food material container 2a induction heating amount for the adjustment of user's wish, need to adjust second frequency f greater than the restriction of people's audible sound pitch critical frequency according to difference on the frequency again ₂The second high frequency values f _2HIn the 3rd time interval T _A3The time, control unit 14 can be with second frequency f ₂Be whole the second low frequency value f of homophony _2L, and according to adjusting signal K ₁Control Power supply unit 13 produces corresponding second frequency f ₂, make the second induction coil 11b to the add heat of the second food material container 2b induction heating amount for the adjustment of user's wish, need to adjust first frequency f greater than the restriction of people's audible sound pitch critical frequency according to difference on the frequency again ₁The first high frequency values f _1H

Because control unit 14 is respectively at interval T of the very first time _A1With the 3rd time interval T _A3With first frequency f ₁Or second frequency f ₂Be main, adjust the first low frequency value f _1LOr the second low frequency value f _1L, therefore, can make first on average to add heat P ₁With second on average add heat P ₂Be adjusted into respectively the heat that adds of user's wish adjustment.In certain embodiments, control unit 14 more can be by adjusting respectively interval T of the very first time _A1, the second time interval T _A2And the 3rd time interval T _A3, make first on average to add heat P ₁With second on average add heat P ₂Be adjusted into respectively the heat that adds of user's wish adjustment.

See also Fig. 3 B and cooperate Fig. 1 and Fig. 3 A, it is the first frequency of the heater of another preferred embodiment of the present invention and the frequency sequential schematic diagram of second frequency.Fig. 3 B is similar in appearance to Fig. 3 A, shown in Fig. 3 B, and first frequency f ₁In interval T of the very first time _A1Be the first high frequency values f _1H, first frequency f ₁In the 3rd time interval T _A3Be the first low frequency value f _1L, and second frequency f ₂In interval T of the very first time _A1Be the second low frequency value f _2L, second frequency f ₂In the 3rd time interval T _A3Be the second high frequency values f _2HThe first induction coil 11a on average adds heat P to first of the first food material container 2a ₁Relational expression is:

$P_1={\mathrm{<figure-callout\; id="1L"\; label="P"\; filenames="H2009101288867E00071.png"\; state="\{\{state\}\}">P</figure-callout>}}_{1L}\left({\mathrm{<figure-callout\; id="1L"\; label="f"\; filenames="H2009101288867E00071.png"\; state="\{\{state\}\}">f</figure-callout>}}_{1L}\right)\&CenterDot;\frac{T_{a3}}{T_a}+P_{1H}\left(f_{1H}\right)\&CenterDot;\frac{T_{a1}+T_{a2}}{T_a},$

As for, the second induction coil 11b on average adds heat P to second of the second food material container 2b ₂Relational expression is:

$P_2=P_{2L}\left(f_{2L}\right)\&CenterDot;\frac{T_{a1}}{T_a}+P_{2H}\left(f_{2H}\right)\&CenterDot;\frac{T_{a2}+T_{a3}}{T_a}.$

In the present embodiment, in interval T of the very first time _A1The time, control unit 14 can be with second frequency f ₂Be whole the second low frequency value f of homophony _2L, and according to adjusting signal K ₁Control Power supply unit 13 produces corresponding second frequency f ₂, make the second induction coil 11b to the add heat of the second food material container 2b induction heating amount for the adjustment of user's wish, need to adjust first frequency f greater than the restriction of people's audible sound pitch critical frequency according to difference on the frequency again ₁The first high frequency values f _1HIn the 3rd time interval T _A3The time, control unit 14 can be with first frequency f ₁Be whole the first low frequency value f of homophony _1L, and according to adjusting signal K ₁Control Power supply unit 13 produces corresponding first frequency f ₁, make the first induction coil 11a to the add heat of the first food material container 2a induction heating amount for the adjustment of user's wish, need to adjust second frequency f greater than the restriction of people's audible sound pitch critical frequency according to difference on the frequency again ₂The second high frequency values f _2H

Similarly, since control unit 14 respectively at interval T of the very first time _A1With the 3rd time interval T _A3With first frequency f ₁Or second frequency f ₂Be main, adjust the first low frequency value f _1LOr the second low frequency value f _2L, therefore, can make first on average to add heat P ₁With second on average add heat P ₂Be adjusted into respectively the heat that adds of user's wish adjustment.In certain embodiments, control unit 14 more can be by adjusting respectively interval T of the very first time _A1, the second time interval T _A2And the 3rd time interval T _A3, make first on average to add heat P ₁With second on average add heat P ₂Be adjusted into respectively the heat that adds of user's wish adjustment.

In addition, in certain embodiments, control unit 14 can be with the first high frequency values f _1H, the second high frequency values f _2H, the first low frequency value f _1LWith the second low frequency value f _2LBe maintained respectively the first maximum frequency values f _Max1, the second maximum frequency values f _Max2, the first minimum frequency value f _Min1With the second minimum frequency value f _Min2, again by adjusting respectively interval T of the very first time _A1, the second time interval T _A2And the 3rd time interval T _A3Time span, realize that the first induction coil 11a is respectively the heat that adds of user's wish adjustment to the second food material container 2b induction heating amount to the first food material container 2a induction heating amount and the second induction coil 11b.Because, the first high frequency values f _1H, the second high frequency values f _2H, the first low frequency value f _1LWith the second low frequency value f _2LMaintain respectively the first maximum frequency values f _Max1, the second maximum frequency values f _Max2, the first minimum frequency value f _Min1With the second minimum frequency value f _Min2After the temperature of the first food material container 2a and the second food material container 2b rises to the temperature of user's setting, for the first food material container 2a and the second food material container 2b being maintained the temperature that the user sets, the size that control unit 14 can run off according to heat is suitably with interval T of the very first time _A1, the second time interval T _A2Or the 3rd time interval T _A3Time span be adjusted into zero.

As for, interval T of the above-mentioned very first time _A1, the second time interval T _A2, the 3rd time interval T _A3And the 4th time interval T _A4, more can not limit sequencing, adjust arbitrarily or interval T of the ordering very first time _A1, the second time interval T _A2, the 3rd time interval T _A3And the 4th time interval T _A4Sequencing, heater 1 can reach above-mentioned function equally.

In sum, heater 1 of the present invention will be divided at least interval T of the very first time running time _A1With the second time interval T _A2, in one of them time interval, interval T of the very first time for example _A1, except being sent to the first frequency f of the first induction coil 11a ₁With the second frequency f that is sent to the second induction coil 11b ₂Setting is greater than outside people's audible sound pitch critical frequency, more with first frequency f ₁With second frequency f ₂Difference on the frequency be set as greater than people's audible sound pitch critical frequency or less than the low critical frequency of people's sub-audible sound, can not produce the noise of uncontrollable volume when the first induction coil 11a and the second induction coil 11b are moved.More in another time interval, the second time interval T for example _A2, stop the operation of the first induction coil 11a, make second frequency f ₂Frequency values only need to be greater than the Single restriction of people's audible sound pitch critical frequency, and then make add heat or the heating-up temperature of the first induction coil 11a and the second induction coil 11b can be correctly add heat or heating-up temperature for the adjustment of user's wish.

In addition, heater 1 of the present invention can detect first some correct heat characteristic parameter values when bringing into operation, for example the first minimum frequency value f _Min1, the second minimum frequency value f _Min2, the first minimal power values P _Min1And the second minimal power values P _Min2, and control unit 14 is in calculating interval T of the very first time _A1, the second time interval T _A2, the 3rd time interval T _A3, the 4th time interval T _A4, first on average add heat P ₁With second on average add heat P ₂The time, use correct heat characteristic parameter value calculation and produce corresponding control signal K ₂, therefore, the problem that heater 1 can't correctly reach the heating-up temperature of wish adjustment or add heat can not occur in heater 1 of the present invention.Moreover because heater 1 of the present invention has a time interval at least, the first induction coil 11a and the second induction coil 11b be induction heating simultaneously, more can make the heating time of Integral heating device 1 shorter.

The present invention must be appointed by those of ordinary skills and executes that the craftsman thinks and be to modify as all, right neither scope of taking off such as the wish protection of attached claim institute.

Claims (39)

1. heater, in order to at least one food material container induction heating, this heater comprises:

One first induction coil;

One second induction coil;

One control panel, signal is adjusted in corresponding generation one with the heat energy size of this second induction coil in order to adjust this first induction coil;

One Power supply unit is connected in this first induction coil and this second induction coil, in order to provide respectively one first power supply and a second source to this first induction coil and this second induction coil; And

One control unit is connected in this control panel and this Power supply unit, in order to produce this first power supply and this second source that a control signal is controlled this Power supply unit according to this adjustment signal;

Wherein, controlling this Power supply unit in interval this control unit of a very first time provides electric energy to this first induction coil and this second induction coil simultaneously, and the difference on the frequency of this first power supply and this second source is greater than 15 KHz or less than 1 KHz, and control this Power supply unit in one second this control unit of time interval and stop to provide electric energy to this first induction coil or this second induction coil, and this control unit is before this very first time interval and this second time interval, detect first a heat characteristic parameter value, this heat characteristic parameter value is one first minimum frequency value, one second minimum frequency value, one first minimal power values and one second minimal power values.

2. heater as claimed in claim 1, wherein this first induction coil and this second induction coil are respectively to one first food material container and one second food material container induction heating.

3. heater as claimed in claim 1, wherein this control unit produces this control signal exports this first induction coil and this second induction coil to control this Power supply unit electric weight size according to this adjustment signal.

4. heater as claimed in claim 1, wherein this control unit is pulse frequency modulated controller or digital signal processor.

5. heater as claimed in claim 1, wherein this control panel comprises at least two buttons and adjusts elements or rotary adjustment element.

6. heater as claimed in claim 1, wherein this Power supply unit is the AC-AC change-over circuit.

7. heater as claimed in claim 1, the wherein alternating voltage of this Power supply cell translation one input power and frequency and produce respectively this first power supply and this second source is sent to this first induction coil and this second induction coil.

8. heater as claimed in claim 1, wherein this Power supply unit makes a first frequency of this first power supply and a second frequency of this second source change adjusting signal according to this control signal, exports the electric weight size of this first induction coil and this second induction coil to control this Power supply unit.

9. heater as claimed in claim 8, wherein this control unit is before this very first time interval and this second time interval, control the frequency values that this Power supply unit little by little reduces this first frequency, this the first minimum frequency value corresponding to this first frequency when detecting this first induction coil as first maximum power value, and this first frequency this first minimal power values corresponding to this first induction coil when being first maximum frequency values.

10. heater as claimed in claim 9, wherein before interval and this second time interval, this second source of more controlling this Power supply unit is that zero voltage value is so that this second induction coil is out of service to this control unit in this very first time.

11. heater as claimed in claim 8, wherein this control unit is before this very first time interval and this second time interval, control the frequency values that this Power supply unit little by little reduces this second frequency, this the second minimum frequency value corresponding to this second frequency when detecting this second induction coil as second maximum power value, and this second frequency this second minimal power values corresponding to this second induction coil when being second maximum frequency values.

12. heater as claimed in claim 11, wherein this control unit is before this very first time interval and this second time interval, and this first power supply of more controlling this Power supply unit is that zero voltage value is so that this first induction coil is out of service.

13. heater as claimed in claim 8, wherein interval in this very first time, difference on the frequency circle of this first frequency and this second frequency is in 15 KHz～25 KHz, and the frequency values of this first frequency and this second frequency is greater than 15 KHz.

14. heater as claimed in claim 8, wherein in this second time interval, this first power supply is zero voltage value, and the frequency values of this second frequency is greater than 15 KHz.

15. heater as claimed in claim 8, wherein this control unit is controlled this first frequency and this second frequency that this Power supply unit repeats this very first time interval and this second time interval, to adjust the heat that adds of this first induction coil and this second induction coil.

16. heater as claimed in claim 8, also comprise one the 3rd time interval and one the 4th time interval, be connected in after this very first time interval and this second time interval, wherein, exchange the operation of this first frequency and this second frequency in the 3rd time interval.

17. heater as claimed in claim 16, wherein this control unit is adjusted more respectively the time span of this very first time interval, this second time interval, the 3rd time interval and the 4th time interval.

18. heater as claimed in claim 16, wherein this control unit prior to this very first time interval take the frequency values of this first frequency as whole this first frequency of homophony, again in the exchange of the 3rd time interval, take the frequency values of this second frequency as whole this second frequency of homophony.

19. heater as claimed in claim 16, wherein this control unit prior to this very first time interval take the frequency values of this second frequency as whole this second frequency of homophony, again in the exchange of the 3rd time interval, take the frequency values of this first frequency as whole this first frequency of homophony.

20. a heater, in order to at least one food material container induction heating, this heater comprises:

One first induction coil;

One second induction coil;

One control panel, signal is adjusted in corresponding generation one with the heat energy size of this second induction coil in order to adjust this first induction coil;

One Power supply unit is connected in this first induction coil and this second induction coil, in order to provide respectively one first power supply and a second source to this first induction coil and this second induction coil; And

One control unit is connected in this control panel and this Power supply unit, in order to produce this first power supply and this second source that a control signal is controlled this Power supply unit according to this adjustment signal;

Wherein, interval and one the 3rd time interval in a very first time, the difference on the frequency of this first power supply and this second source is greater than 15 KHz, and in one second time interval, the difference on the frequency of this first power supply and this second source is less than 1 KHz, and this control unit is before this very first time interval, this second time interval and the 3rd time interval, detect first a heat characteristic parameter value, this heat characteristic parameter value is one first minimum frequency value, one second minimum frequency value, one first minimal power values and one second minimal power values.

21. heater as claimed in claim 20, wherein this first induction coil and this second induction coil are respectively to one first food material container and one second food material container induction heating.

22. heater as claimed in claim 20, wherein this control unit produces this control signal exports this first induction coil and this second induction coil to control this Power supply unit electric weight size according to this adjustment signal.

23. heater as claimed in claim 20, wherein this control unit is pulse frequency modulated controller or digital signal processor.

24. heater as claimed in claim 20, wherein this control panel comprises at least two buttons adjustment elements or rotary adjustment element.

25. heater as claimed in claim 20, wherein this Power supply unit is the AC-AC change-over circuit.

26. heater as claimed in claim 20, the wherein alternating voltage of this Power supply cell translation one input power and frequency and produce respectively this first power supply and this second source is sent to this first induction coil and this second induction coil.

27. heater as claimed in claim 20, wherein this Power supply unit makes a first frequency of this first power supply and a second frequency of this second source change adjusting signal according to this control signal, exports the electric weight size of this first induction coil and this second induction coil to control this Power supply unit.

28. heater as claimed in claim 20, wherein, this first frequency corresponded to this first minimum frequency value when this first induction coil was first maximum power value, this second frequency corresponded to this second minimum frequency value when this second induction coil was second maximum power value, this first induction coil corresponded to this first minimal power values when this first frequency was first maximum frequency values, and this second induction coil corresponded to this second minimal power values when this second frequency was second maximum frequency values.

29. heater as claimed in claim 27, wherein this control unit is before this very first time interval, this second time interval and the 3rd time interval, control the frequency values that this Power supply unit little by little reduces this first frequency, this the first minimum frequency value corresponding to this first frequency when detecting this first induction coil as this first maximum power value, and this first frequency this first minimal power values corresponding to this first induction coil when being this first maximum frequency values.

30. heater as claimed in claim 29, wherein this control unit is before this very first time interval, this second time interval and the 3rd time interval, and this second source of more controlling this Power supply unit is that zero voltage value is so that this second induction coil is out of service.

31. heater as claimed in claim 28, wherein this control unit is before this very first time interval, this second time interval and the 3rd time interval, control the frequency values that this Power supply unit little by little reduces this second frequency, this the second minimum frequency value corresponding to this second frequency when detecting this second induction coil as this second maximum power value, and this second frequency this second minimal power values corresponding to this second induction coil when being this second maximum frequency values.

32. heater as claimed in claim 31, wherein this control unit is before this very first time interval, this second time interval and the 3rd time interval, and this first power supply of more controlling this Power supply unit is that zero voltage value is so that this first induction coil is out of service.

33. heater as claimed in claim 28, wherein in this second time interval, this first frequency and this second frequency are respectively one first high frequency values and one second high frequency values, and in this very first time interval or the 3rd time interval one of them correspond to one first low frequency value or one second low frequency value.

34. heater as claimed in claim 33, wherein this first frequency is this first low frequency value in this very first time interval, this first frequency is this first high frequency values in the 3rd time interval, and this second frequency is this second high frequency values in this very first time interval, and this second frequency is this second low frequency value in the 3rd time interval.

35. heater as claimed in claim 33, wherein this first frequency is this first high frequency values in this very first time interval, this first frequency is this first low frequency value in the 3rd time interval, and this second frequency is this second low frequency value in this very first time interval, and this second frequency is this second high frequency values in the 3rd time interval.

36. heater as claimed in claim 33, wherein this first low frequency value and this second low frequency value are set as respectively this first minimum frequency value and this second minimum frequency value, and this first high frequency values and this second high frequency values are set as respectively this first maximum frequency values and this second maximum frequency values, and this control unit is adjusted respectively the time span of this very first time interval, this second time interval and the 3rd time interval.

37. heater as claimed in claim 27, wherein in this very first time interval and the 3rd time interval, difference on the frequency circle of this first frequency and this second frequency is in 15 KHz～25 KHz, and the frequency values of this first frequency and this second frequency is greater than 15 KHz.

38. heater as claimed in claim 27, wherein this control unit is controlled this first frequency and this second frequency that this Power supply unit repeats this very first time interval, this second time interval and the 3rd time interval, to adjust the heat that adds of this first induction coil and this second induction coil.

39. heater as claimed in claim 20, wherein this control unit is adjusted more respectively the time span of this very first time interval, this second time interval and the 3rd time interval, and the time span of should the very first time interval, this second time interval and the 3rd time interval is adjusted into zero, so that at least one this food material container is maintained at a design temperature.

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