CN116263358A - Heating temperature measurement circuit and cooking device - Google Patents
Heating temperature measurement circuit and cooking device Download PDFInfo
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- CN116263358A CN116263358A CN202111542405.4A CN202111542405A CN116263358A CN 116263358 A CN116263358 A CN 116263358A CN 202111542405 A CN202111542405 A CN 202111542405A CN 116263358 A CN116263358 A CN 116263358A
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- 238000010438 heat treatment Methods 0.000 title claims abstract description 39
- 238000010411 cooking Methods 0.000 title claims abstract description 18
- 238000009529 body temperature measurement Methods 0.000 title abstract description 19
- 239000002184 metal Substances 0.000 claims abstract description 105
- 229910052751 metal Inorganic materials 0.000 claims abstract description 105
- 230000006698 induction Effects 0.000 claims abstract description 55
- 238000005070 sampling Methods 0.000 claims abstract description 46
- 230000008859 change Effects 0.000 claims abstract description 15
- 230000001939 inductive effect Effects 0.000 claims abstract description 12
- 230000005284 excitation Effects 0.000 claims description 50
- 238000000034 method Methods 0.000 description 11
- 238000010586 diagram Methods 0.000 description 10
- 230000008878 coupling Effects 0.000 description 8
- 238000010168 coupling process Methods 0.000 description 8
- 238000005859 coupling reaction Methods 0.000 description 8
- 230000004907 flux Effects 0.000 description 6
- 238000012545 processing Methods 0.000 description 6
- 230000008569 process Effects 0.000 description 5
- 238000001514 detection method Methods 0.000 description 4
- 238000004804 winding Methods 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
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- 230000005674 electromagnetic induction Effects 0.000 description 2
- 230000002159 abnormal effect Effects 0.000 description 1
- 238000004132 cross linking Methods 0.000 description 1
- 239000003779 heat-resistant material Substances 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 238000013507 mapping Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K7/00—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements
- G01K7/36—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using magnetic elements, e.g. magnets, coils
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- A—HUMAN NECESSITIES
- A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
- A47J—KITCHEN EQUIPMENT; COFFEE MILLS; SPICE MILLS; APPARATUS FOR MAKING BEVERAGES
- A47J36/00—Parts, details or accessories of cooking-vessels
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B40/00—Technologies aiming at improving the efficiency of home appliances, e.g. induction cooking or efficient technologies for refrigerators, freezers or dish washers
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Abstract
The application discloses heating temperature measurement circuit and cooking device, this heating temperature measurement circuit includes: the exciting coil is used for generating an alternating magnetic field when being electrified so as to enable the metal object to generate electric eddy; the differential coil set is used for inducing the eddy current to generate a first electric signal; the sampling coil is used for sampling a second electric signal of the exciting coil; the induction coil is used for inducing the position change of the metal object to obtain a third electric signal; and the control circuit is connected with the differential coil group, the sampling coil and the induction coil and is used for determining the temperature of the metal object according to the first electric signal, the second electric signal and the third electric signal. Through the mode, the accuracy of temperature measurement of the metal object can be improved.
Description
Technical Field
The application relates to the technical field of temperature detection, in particular to a heating temperature measuring circuit and a cooking device.
Background
In general, when heating a metal object, it is necessary to detect and control the temperature of the metal object, for example, a cooking device, and in order to achieve good control of the cooking device, it is necessary to measure the temperature of the metal object by heating the metal object by the cooking device. For example, when a set heating curve is used to heat a metal object, it is necessary to detect whether the temperature of the metal object satisfies the set heating curve, and for example, when the temperature of the metal object is abnormal, the cooking device may be caused to suspend heating.
One existing method is to detect the temperature of a metal object by a thermistor, but the temperature detection is inaccurate due to the problem of position setting of the thermistor.
Disclosure of Invention
For solving above-mentioned problem, this application provides heating temperature measurement circuit and cooking device, can promote the accuracy of carrying out temperature measurement to the metal object.
The application adopts a technical scheme that: there is provided a heating and temperature measuring circuit including: the exciting coil is used for generating an alternating magnetic field when being electrified so as to enable the metal object to generate electric eddy; the differential coil set is used for inducing the eddy current to generate a first electric signal; the sampling coil is used for sampling a second electric signal of the exciting coil; the induction coil is used for inducing the position change of the metal object to obtain a third electric signal; and the control circuit is connected with the differential coil group, the sampling coil and the induction coil and is used for determining the temperature of the metal object according to the first electric signal, the second electric signal and the third electric signal.
Wherein, differential coil group includes: the first coil is arranged corresponding to the exciting coil; and the second coil is sleeved on the connecting wire of the excitation coil.
The exciting coil is arranged as a coil disc, and the first coil is arranged corresponding to the center of the coil disc.
The sampling coil is sleeved on the connecting wire of the excitation coil.
Wherein the induction coil coverage area corresponds to at least a plurality of different locations of the excitation coil coverage area; the control circuit is used for: determining a first phase difference of the first electrical signal and the second electrical signal; correcting the first phase difference according to the amplitude change condition of the third electric signal to obtain a second phase difference; the temperature of the metal object is determined from the second phase difference.
The coverage area of the exciting coil comprises a geometric center point and at least one distribution point pair symmetrical based on the geometric center point, and the coverage area of the induction coil at least corresponds to the at least one distribution point pair.
The induction coil comprises a plurality of sub-coils, the third electric signal comprises a plurality of sub-signals, and the plurality of sub-coils at least correspond to a plurality of different positions of the coverage area of the excitation coil; the control circuit is used for: determining a first phase difference of the first electrical signal and the second electrical signal; correcting the first phase difference according to the plurality of sub-signals to obtain a second phase difference; the temperature of the metal object is determined from the second phase difference.
The coverage area of the excitation coil comprises a geometric center point and at least one distribution point pair symmetrical based on the geometric center point, and the plurality of sub-coils at least correspond to the at least one distribution point pair; the control circuit is used for: determining the ratio of two sub-signals corresponding to the two sub-coils of at least one distribution point pair as a compensation value; the sum of the first phase difference and the compensation value is determined as the second phase difference.
Wherein the coverage area of the excitation coil comprises a geometric center point, and the plurality of sub-coils are uniformly distributed in a circumferential direction based on the geometric center point.
The other technical scheme adopted by the application is as follows: the cooking device comprises the heating temperature measuring circuit.
The application provides a heating temperature measurement circuit includes: the exciting coil is used for generating an alternating magnetic field when being electrified so as to enable the metal object to generate electric eddy; the differential coil set is used for inducing the eddy current to generate a first electric signal; the sampling coil is used for sampling a second electric signal of the exciting coil; the induction coil is used for inducing the position change of the metal object to obtain a third electric signal; and the control circuit is connected with the differential coil group, the sampling coil and the induction coil and is used for determining the temperature of the metal object according to the first electric signal, the second electric signal and the third electric signal. Through the above-mentioned mode, utilize differential coil group, sampling coil and induction coil to gather corresponding electrical signal respectively, and then confirm the temperature of metal object according to the electrical signal that gathers, compare in the mode that utilizes differential coil and sampling coil to carry out temperature determination among the correlation technique, this embodiment utilizes differential coil and induction coil to carry out temperature determination, can solve the problem that the temperature deviation that removes the metal object to cause is big, and then promotes the accuracy of carrying out temperature measurement to the metal object.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art. Wherein:
FIG. 1 is a schematic diagram of an embodiment of a heating and temperature measuring circuit provided in the present application;
FIG. 2 is a schematic structural view of an embodiment of the exciting coil, the first coil and the metal object provided in the present application;
FIG. 3 is a schematic diagram of an embodiment of an excitation coil and an induction coil provided herein;
FIG. 4 is a schematic diagram of an embodiment of an excitation coil provided herein;
FIG. 5 is a schematic diagram of another embodiment of an excitation coil and an induction coil provided herein;
FIG. 6 is a schematic structural view of another embodiment of the excitation coil and induction coil provided herein;
FIG. 7 is an equivalent circuit diagram of the excitation coil, the first coil, the second coil, the sampling coil, and the metal object provided herein;
FIG. 8 is a schematic diagram of a phase difference curve of a heating temperature measurement circuit provided by the application without an induction coil;
FIG. 9 is a schematic diagram of compensation values in the heating and temperature measuring circuit provided by the application;
FIG. 10 is a schematic diagram of a phase difference when the heating and temperature measuring circuit provided by the application is compensated by an induction coil;
fig. 11 is a schematic structural view of a first embodiment of a cooking apparatus provided in the present application;
fig. 12 is a schematic structural view of a second embodiment of the cooking apparatus provided herein;
fig. 13 is a schematic structural view of a third embodiment of a cooking apparatus provided in the present application.
Detailed Description
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. It is to be understood that the specific embodiments described herein are for purposes of illustration only and are not limiting. It should be further noted that, for convenience of description, only some, but not all of the structures related to the present application are shown in the drawings. All other embodiments, which can be made by one of ordinary skill in the art based on the embodiments herein without making any inventive effort, are intended to be within the scope of the present application.
The terms "first," "second," and the like in this application are used for distinguishing between different objects and not for describing a particular sequential order. Furthermore, the terms "comprise" and "have," as well as any variations thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, system, article, or apparatus that comprises a list of steps or elements is not limited to only those listed steps or elements but may include other steps or elements not listed or inherent to such process, method, article, or apparatus.
Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the present application. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those of skill in the art will explicitly and implicitly appreciate that the embodiments described herein may be combined with other embodiments.
The inventor researches for a long time to find that the related non-contact temperature measurement can cause the problems of large temperature deviation and the like when moving the metal object, and based on the problems, the application provides the following scheme for solving the problems of large temperature deviation when moving the metal object.
Referring to fig. 1, fig. 1 is a schematic structural diagram of an embodiment of a heating and temperature measuring circuit provided in the present application. The heating temperature measurement circuit comprises: the device comprises an excitation coil L1, a differential coil group 11, a sampling coil L5, an induction coil LX and a control circuit 13.
The exciting coil L1 is used for generating an alternating magnetic field when being electrified, so that the metal object generates eddy current.
The differential coil set 11 is used for inducing eddy currents to generate a first electrical signal.
The partial coils in the differential coil group 11 may be disposed within an electromagnetic coupling range of the excitation coil L1, which generates an alternating magnetic field when energized.
The sampling coil L5 is used for sampling the second electric signal of the excitation coil L1.
The induction coil LX is used for inducing the position change of the metal object to obtain a third electric signal.
The control circuit 13 is connected to the differential coil group 11, the sampling coil L5 and the induction coil LX for determining the temperature of the metal object from the first electrical signal, the second electrical signal and the third electrical signal.
Specifically, a correction value may be determined based on the third electrical signal, and the original calculation mode may be compensated by using the correction value, so as to determine the temperature of the metal object.
Wherein the exciting coil L1 is used for carrying out resonance heating on the metal object. Part of the coils in the differential coil group 11 may be mutually-inductive with the excitation coil L1 and the metal object, respectively. The remaining coils in the differential coil group 11 may be mutually inductive with the excitation coil L1.
In some embodiments, the degree of electromagnetic induction between coils is related not only to the mutual inductance between them, but also to their respective self-inductance, and depends on the degree of tightness of the flux linkage coupling between the coils. For example, the degree of tightness of the flux linkage coupling between two coils is expressed by a coupling coefficient "k", and generally the magnetic flux generated by one coil cannot pass through the other coil, so that in general, the coupling coefficient k <1, k=1 if the leakage magnetic flux is small and negligible. In addition, the mutual inductance M between two coils is an intrinsic parameter of the coils and depends on the number of turns, the geometric dimensions, the relative positions of the two coils and the magnetic medium. The value of M reflects the ability of one coil to generate magnetic flux in the other.
In this embodiment, the differential coil set 11, the sampling coil L5 and the induction coil LX are used to collect corresponding electrical signals respectively, and then the temperature of the metal object is determined according to the collected electrical signals, compared with the mode of determining the temperature by using the differential coil set 11 and the sampling coil L5 in the related art, the temperature determination by using the differential coil set 11 and the induction coil LX in this embodiment can solve the problem of large temperature deviation caused by moving the metal object, and further the accuracy of temperature measurement on the metal object is improved.
Further, the description is continued with reference to fig. 1:
wherein the differential coil group 11 includes: a first coil L2 and a second coil L3.
Wherein the first coil L2 is arranged corresponding to the excitation coil L1; for example, in the electromagnetic coupling range of the excitation coil L1. The second coil L3 is sleeved on the connecting wire of the exciting coil L1. It will be appreciated that the coil includes, in addition to the coil-shaped region, a connection wire for generating an alternating magnetic field when energized, the connection wire being responsible for connecting to a power supply for switching in the electrical signal.
Wherein, the first end of the first coil L2 is connected with the first end of the second coil L3, and the second end of the first coil L2 and the second end of the second coil L3 are both connected with the control circuit 13. The first end of the first coil L2 and the first end of the second coil L3 are identical-name ends, that is, the identical-name ends of the first coil L2 and the second coil L3 are connected, and the second coil L3 is sleeved on the connecting wire of the exciting coil L1.
It will be appreciated that the physical phenomenon of the current carrying coils being interconnected by the magnetic fields of each other is known as magnetic coupling. The direction of magnetic flux generated by the induced current and the situation of cross-linking each other are determined according to the right spiral rule according to the winding direction of the two coils, the reference direction of the magnetic induced current and the relative position of the two coils. If the directions of the first coil L2 and the second coil L3 are identical, the start ends of the two coil windings are identical to each other, and the end ends of the two coil windings are identical to each other.
Because the same-name ends of the first coil L2 and the second coil L3 are connected, mutual inductance between the second coil L3 and the exciting coil L1 can eliminate mutual inductance between the first coil L2 and the exciting coil L1, so that the first electric signal received by the control circuit 13 is only mutual inductance of the eddy current reflected by the first coil L2 and the metal object.
In some embodiments, the electrical parameters of the first coil L2 and the second coil L3 are the same. For example, each turn of the first coil L2 is thicker than each turn of the second coil L3, but the number of turns of the second coil L3 is greater than the number of turns of the first coil L2.
It will be appreciated that in this way, the mutual inductances formed by the first coil L2 and the second coil L3, respectively, and the excitation coil L1 are identical in value, under the same conditions of the electrical parameters. Since the same-name ends of the first coil L2 and the second coil L3 are connected, they can cancel each other.
The control circuit 13 collects a first electrical signal by connecting the first coil L2 and the second coil L3, and the control circuit 13 collects a third electrical signal by connecting the induction coil LX, and the control circuit 13 collects a second electrical signal by connecting the sampling coil L5. The control circuit 13 determines the temperature of the metal object from the first electrical signal, the second electrical signal and the third electrical signal.
In this embodiment, the differential coil set 11, the induction coil LX and the sampling coil L5 are utilized to determine the temperature, so that the problem of large temperature deviation caused by moving a metal object can be solved, and the accuracy of temperature measurement on the metal object is further improved.
In some embodiments, as shown in fig. 2, the excitation coil L1 is provided as a coil disk, and the first coil L2 is provided corresponding to the center of the coil disk. Wherein the first coil L2 and the excitation coil L1 are coaxially arranged. In other embodiments, the first coil L2 may be coaxially disposed on one side of the exciting coil L1, for example, on the side of the exciting coil L1 near the metal object, or on the side of the exciting coil L1 far from the metal object.
In other embodiments, the first coil L2 is in a three-dimensional spiral shape, and the first coil L2 and the excitation coil L1 are coaxially disposed.
Through the center setting that corresponds the coil panel with first coil L2, can carry out electromagnetic coupling with the metal object when carrying out temperature measurement, obtain great mutual inductance relatively, and then can promote the accuracy of the temperature of measuring.
The sampling coil L5 is sleeved on the connecting wire of the exciting coil L1. In an application scene, the sampling coil L5 is not mutually induced with the metal object and can be arranged far away from the placement area of the metal object. The electrical parameters of the sampling coil L5 may be the same as or different from those of the first coil L2.
In some embodiments, the induction coil LX may be disposed on a side of the excitation coil L1 close to the metal object, or on a side of the excitation coil L1 away from the metal object. Wherein the coverage area of the induction coil LX corresponds to at least a plurality of different locations of the coverage area of the excitation coil L1. As shown in fig. 3, the induction coil LX has a cross shape for inducing a change in the position of the metal object to obtain a third electric signal. Specifically, the induction coil LX receives an electric signal reflected by a metal object in mutual inductance with the excitation coil L1.
The control circuit 13 is configured to determine a first phase difference of the first electrical signal and the second electrical signal; correcting the first phase difference according to the amplitude change condition of the third electric signal to obtain a second phase difference; the temperature of the metal object is determined from the second phase difference.
It will be appreciated that when the metal object moves and the position changes, the region where the metal object is mutually induced with the exciting coil L1 also changes, and thus the electric signal reflected by the metal object also changes. Thus, the first electrical signal also changes, while the second electrical signal of the sampling coil L5 sampling the excitation coil L1 does not change, the temperature as originally calculated is inaccurate. In some embodiments, the maximum value of the amplitude of the third electrical signal and the minimum value of the amplitude may be used to obtain a comparison value, and then the comparison value is used to correct the first phase difference to obtain a second phase difference; the temperature of the metal object is determined from the second phase difference.
In some embodiments, the coverage area of the excitation coil L1 includes a geometric center point and at least one distribution point pair symmetrical based on the geometric center point, and the coverage area of the induction coil LX corresponds to at least one distribution point pair.
As shown in fig. 4, the coverage area of the excitation coil L1 includes a geometric center point O, and distribution points a and B based on geometric center point symmetry, and distribution points C and D based on geometric center point symmetry. The distribution points A and B are a distribution point pair, and the distribution points C and D are a distribution point pair. The coverage area of the induction coil LX may correspond to the distribution point a and the distribution point B, or correspond to the distribution point C and the distribution point D. Or the coverage area of the induction coil LX may correspond to the distribution points a and B and to the distribution points C and D.
In some embodiments, the induction coils LX may be disposed above, below, or at distribution points of the respective distribution points.
In some embodiments, the induction coil LX comprises a plurality of sub-coils, the third electrical signal comprising a plurality of sub-signals, the plurality of sub-coils corresponding to at least a plurality of different locations of the coverage area of the excitation coil L1; the control circuit 13 is configured to determine a first phase difference of the first electrical signal and the second electrical signal; correcting the first phase difference according to the plurality of sub-signals to obtain a second phase difference; the temperature of the metal object is determined from the second phase difference.
As shown in fig. 5, the induction coil LX includes a first sub-coil LX1, a second sub-coil LX2, a third sub-coil LX3, and a fourth sub-coil LX4. The first, second, third and fourth sub-coils LX1, LX2, LX3 and LX4 correspond to a plurality of different locations of the coverage area of the excitation coil L1. The electric signals at different positions can be sensed.
In some embodiments, the coverage area of the excitation coil L1 includes a geometric center point, and at least one distribution point pair symmetrical based on the geometric center point, and the plurality of sub-coils correspond to at least one distribution point pair; the control circuit 13 is configured to determine, as a compensation value, a ratio of two sub-signals corresponding to two sub-coils of at least one distribution point pair; the sum of the first phase difference and the compensation value is determined as the second phase difference.
Referring to fig. 4 and 5, in fig. 4, the coverage area of the excitation coil L1 includes a geometric center point O, and distribution points a and B based on geometric center point symmetry, and distribution points C and D based on geometric center point symmetry. The first sub-coil LX1 in fig. 5 may correspond to the distribution point a, the third sub-coil LX3 may correspond to the distribution point B, the second sub-coil LX2 may correspond to the distribution point C, and the fourth sub-coil LX4 may correspond to the distribution point D.
In some embodiments, the temperature detection is illustrated with two sub-coil pairs corresponding to one distribution point:
if the first sub-coil LX1 can correspond to the distribution point a and the third sub-coil LX3 can correspond to the distribution point B, the first sub-coil LX1 can sense a first sub-signal, the third sub-coil LX3 can sense a second sub-signal, and then the ratio of the first sub-signal to the second sub-signal is determined, and the ratio is used as a compensation value; the sum of the first phase difference and the compensation value is determined as the second phase difference. The temperature of the metal object is determined from the second phase difference.
In some embodiments, the temperature detection is illustrated with four sub-coil pairs corresponding to two distribution points:
if the first sub-coil LX1 can correspond to the distribution point a and the third sub-coil LX3 can correspond to the distribution point B, the first sub-coil LX1 can sense the first sub-signal, the third sub-coil LX3 can sense the second sub-signal, and the first ratio of the first sub-signal to the second sub-signal is determined.
The second sub-coil LX2 may correspond to the distribution point C, and the fourth sub-coil LX4 may correspond to the distribution point D, so that the second sub-coil LX2 can sense the third sub-signal, the fourth sub-coil LX4 can sense the fourth sub-signal, and a second ratio of the third sub-signal to the fourth sub-signal is determined.
Determining the average value of the first ratio and the second ratio to obtain an average ratio, and taking the average ratio as a compensation value; the sum of the first phase difference and the compensation value is determined as the second phase difference. The temperature of the metal object is determined from the second phase difference.
The process by which the control circuit 13 determines the temperature of the metal object can be expressed by the following formula:
T＝K*(△φ+ε)+C。
wherein T represents the measured temperature of the metal object, deltaphi represents the first phase difference, epsilon represents the compensation value, deltaphi+epsilon represents the second phase difference, K and C represent constants, wherein K and C are fitted in advance according to the relationship between phase and temperature.
In some embodiments, the coverage area of the excitation coil L1 includes a geometric center point, and the plurality of sub-coils are uniformly distributed in a circumferential direction based on the geometric center point.
As shown in fig. 6, the first sub-coil LX1, the second sub-coil LX2, the third sub-coil LX3, and the fourth sub-coil LX4 are uniformly distributed in the circumferential direction based on the geometric center point O. The third electrical signal is obtained by sensing the change in position of the metal object in the manner according to any of the embodiments described above.
Referring to fig. 7, when the exciting coil L1 performs resonance heating, a resonance current i1 flows through a resonance circuit in which the exciting coil L1 is located. The sampling coil L5 is wound on the magnetizer, and the resonant circuit of the exciting coil L1 passes through the magnetizer, so that the resonating circuit induces a resonant current i1 flowing through the exciting coil L1 and generates a corresponding resonant acquisition voltage u5. The measured voltage output by the first coil L2 and the second coil L3 is denoted as u23.
Specifically, when a metal object is placed on the excitation coil L1, the excitation coil L1 is mutually transformed with the induction inductance Lr of the metal object 30 to obtain a mutual inductance M1r, thereby generating a corresponding induction current ir, wherein the induction current ir flows through the induction inductance Lr and the equivalent thermal resistance Rz.
The first coil L2 is mutually transformed with the exciting coil L1 and the metal object, respectively, and the second coil L3 is mutually transformed with the exciting coil L1. Therefore, the induction inductance Lr of the metal object generates mutual inductance Mr2 with the first coil L2, but does not generate mutual inductance with the second coil L3; the excitation coil L1 generates a mutual inductance M12 with the first coil L2, and generates a mutual inductance M13 with the second coil L3.
The resonance current i1 can be measured by the sampling coil L5, specifically, uin is the mapping voltage of i1, so that the resonance current i1 can be obtained through the resonance acquisition voltage u5 output by the sampling coil L5; u23 is the measured voltage output from the first coil L2 and the second coil L3. Then Mr2 can also be determined after the inductance values of the excitation coil L1, the first coil L2, the second coil L3, the sampling coil L5 and the inductance Lr, and their mutual positions, are determined. Thus, an electrical parameter LR of the metal object can be calculated, wherein the electrical parameter LR can be magnetic permeability or electrical conductivity or equivalent thermal resistance Rz. In some embodiments, the sampling coil L5 may be a current transformer of the excitation coil L1, and samples the resonant current flowing through the excitation coil L1 in the form of mutual inductance.
The temperature coefficient of the induction inductance Lr due to the metal object 30 is small; the equivalent thermal resistance Rz has a larger temperature coefficient, and most stainless steel or iron materials have a temperature coefficient between 0.001 and 0.007 (20 ℃), so that the thermal resistance Rz of the metal object can be deduced when u23, u5 and i1 are measured, and then the temperature of the metal object can be obtained according to a preset thermal resistance-temperature function T=f (Rz).
In an application scenario, the metal object 30 is a metal pot, the exciting coil L1 may be a coil disc, and the sampling coil L5 samples the current of the exciting coil L1; the first coil L2 samples the electric signal of the metal object 30 and the electric signal of the exciting coil L1, the second coil L3 is sleeved on the exciting coil L1, the electric signal of the exciting coil L1 is sampled, and the identical ends of the first coil L2 and the second coil L3 are connected to form a pair of differential coil groups 11.
The differential coil set 11 can eliminate the electric signal of the exciting coil L1 and only retain the electric signal (phase and amplitude) of the metal object 30, and the electric signal sampled by the sampling coil L5 and the electric signal of the differential coil set 11 are subjected to phase difference, namely, ΔΦ=Φl5- Φl2_l3, wherein Φl2_l3 represents the phase of the differential coil set 11, namely, the phase of the first electric signal, and Φl5 represents the phase of the sampling coil L5, namely, the phase of the second electric signal. The electric parameters (magnetic conductivity and electric conductivity) of the metal cookware can be indirectly obtained, and the electric parameters of the metal cookware can change regularly along with the change of temperature, so that the function of the temperature and delta phi of the metal cookware can be established. However, the metal pot is positioned at different positions of the exciting coil L1, and the electric parameters of the metal pot are kept unchanged, but delta phi measured by the sampling coil L5 and the differential coil set 11 is changed, so that the electric signal of the induction coil LX is introduced for compensation.
The metal object 30 has mutual inductance Mr2 to the first coil L2 and no mutual inductance to the second coil L3; the exciting coil L1 has mutual inductance M13 to the second coil L3 and mutual inductance M12 to the first coil L2, so that the mutual inductance of M13= -M12 to the first coil L2 and the second coil L3 is only Mr2, the Mr2 is converted into an electric signal to obtain a first electric signal u23, meanwhile, the sampling coil L5 also measures a second electric signal u5 of the exciting coil L1, and a phase difference delta phi = phi L5-phi L2_L3 is obtained for two groups of signals u23 and u5.
And then determining the compensation value epsilon by using the acquired third electric signal of the induction coil LX. Specifically, the compensation value ε may be determined according to the specific structure of induction coil LX. The compensation value epsilon may in particular be determined in accordance with any of the embodiments described above.
When the position of the metal object 30 is fixed relative to the exciting coil L1, i.e. the coefficient epsilon is fixed, the temperature of the metal object 30 may be expressed as t=k×ΔΦ+c (K and C are constants obtained by fitting in advance according to the relationship between the phase and the temperature), and when the position of the metal object 30 changes relative to the exciting coil L1, ΔΦ changes, the third electric signal of the induction coil LX also changes asymmetrically, i.e. the coefficient epsilon also changes, i.e. it can be understood that ΔΦ changes with the position of the metal object 30, and the formula t=k×ΔΦ+epsilon) +c can be obtained.
The comparison is illustrated in conjunction with fig. 8, 9 and 10:
fig. 8 is a graph of Δφ without compensation, as shown in fig. 8, where the metal object 30 has different Δφ curves at different locations with a uniform temperature differential (90 ℃ to 30 ℃). And as the position in distance is further away, Δφ is smaller.
Referring to fig. 9, the metal object 30 has different epsilon curves at different locations, and epsilon increases with distance.
Thus, compensating for Δφ with ε, the metal cookware has the same Δφ curve at different locations under a uniform temperature differential, as shown in FIG. 10.
So far, the problem of large temperature deviation caused by moving the metal object 30 is solved, and the accuracy of temperature measurement on the metal object 30 is further improved.
Referring to fig. 11, fig. 11 is a schematic structural diagram of an embodiment of a cooking apparatus provided in the present application, and the cooking apparatus 100 includes a heating temperature measurement circuit 10.
The heating and temperature measuring circuit 10 may be the same as the heating and temperature measuring circuit 10 in any of the above embodiments, and detailed description thereof is omitted herein.
In other embodiments, referring to fig. 12, cooking device 100 includes a faceplate 20 and a thermal thermometry circuit 10.
The panel 20 includes a first side and a second side, wherein the first side is a heating surface for placing the metal object 30, and the heating temperature measuring circuit 10 is disposed on the second side. Alternatively, the panel 20 is made of a nonmetallic heat resistant material.
The exciting coil L1 in the heating and temperature measuring circuit 10 generates an alternating magnetic field when energized, and the metal object generates an eddy current under the action of the alternating magnetic field, so as to heat the metal object 30 (metal pot) by the exciting coil L1.
When the temperature of the metal object 30 is measured, an excitation signal is provided for the excitation coil L1, so that the excitation coil L1 generates an alternating magnetic field, the metal object 30 generates electric eddy currents under the action of the alternating magnetic field, and the electric eddy currents further enable the first differential coil set 11 to induce the electric eddy currents to generate a first electric signal through electromagnetic induction; generating a second electric signal by the induced eddy current of the sampling coil L5 group; the induction coil LX inducts the position change of the metal object to obtain a third electric signal; the control circuit 13 determines the temperature of the metal object from the first electric signal, the second electric signal, and the third electric signal.
Referring to fig. 13, the cooking apparatus 100 includes an exciting coil L1, a first coil L2, a second coil L3, an induction coil LX, a sampling coil L5, a control circuit 13, an inverter circuit, and an LX inverter circuit. The control circuit 13 includes a processor 131 and a signal processing circuit 132.
The signal processing circuit 132 is connected to the first coil L2, the second coil L3, the sampling coil L5, and the processor 131, and is configured to receive the first electric signal generated by the induced eddy currents of the first coil L2 and the second coil L3; and the receiving sampling coil L5 samples the second electric signal of the exciting coil L1, and the receiving induction coil LX inducts the position change of the metal object to obtain a third electric signal, and performs signal processing, and sends the processed first electric signal, second electric signal and third electric signal to the processor 131. The signal processing circuit 132 includes circuits such as op-amp and filter, processes the first, second and third electrical signals, and inputs them into the processor 131, so that the processor 131 can complete temperature calculation, and the processor 131 also controls the inverter circuit to operate.
The processor 131 is connected to the inverter circuit, and further controls the inverter circuit to invert the connected voltage into an ac resonance signal through LC resonance, and then supplies the ac resonance signal to the exciting coil L1. The LX inverter circuit excites the induction coil LX to resonate, and the signal processing circuit 132 samples the voltage, current or frequency of the induction coil LX to record.
The direct current power supply DC provides direct current temperature measurement voltage.
In summary, this application utilizes differential coil group 11, sampling coil L5 and induction coil LX to gather corresponding electrical signal respectively, and then confirms the temperature of metal object according to the electrical signal that gathers, compare in the mode that utilizes a set of differential coil and sampling coil to carry out temperature determination among the correlation technique, this embodiment utilizes differential coil group 11 and induction coil LX to carry out temperature determination, can solve the problem that the temperature deviation that removes the metal object to cause is big, and then promotes the accuracy of carrying out temperature measurement to the metal object.
In the several embodiments provided in the present application, it should be understood that the disclosed methods and apparatuses may be implemented in other manners. For example, the above-described device embodiments are merely illustrative, e.g., the division of the modules or units is merely a logical functional division, and there may be additional divisions when actually implemented, e.g., multiple units or components may be combined or integrated into another system, or some features may be omitted, or not performed.
The units described as separate units may or may not be physically separate, and units shown as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the embodiment.
In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, each unit may exist alone physically, or two or more units may be integrated into one unit. The integrated units may be implemented in hardware or in software functional units.
The foregoing description is only of embodiments of the present application, and is not intended to limit the scope of the patent application, and all equivalent structures or equivalent processes according to the specification and drawings of the present application, or direct or indirect application in other related technical fields, are included in the scope of the patent protection of the present application.
Claims (10)
1. A heating and temperature measuring circuit, characterized in that the heating and temperature measuring circuit comprises:
the exciting coil is used for generating an alternating magnetic field when being electrified so as to enable the metal object to generate electric eddy;
the differential coil set is used for inducing the electric eddy current to generate a first electric signal;
a sampling coil for sampling a second electrical signal of the excitation coil;
the induction coil is used for inducing the position change of the metal object to obtain a third electric signal;
and the control circuit is connected with the differential coil group, the sampling coil and the induction coil and is used for determining the temperature of the metal object according to the first electric signal, the second electric signal and the third electric signal.
2. The heating and temperature measuring circuit according to claim 1, wherein,
the differential coil set includes:
a first coil arranged corresponding to the excitation coil;
the second coil is sleeved on the connecting wire of the excitation coil.
3. The heating and temperature measuring circuit according to claim 2, wherein,
the exciting coil is arranged as a coil panel, and the first coil is arranged corresponding to the center of the coil panel.
4. The heating and temperature measuring circuit according to claim 1, wherein,
the sampling coil is sleeved on the connecting wire of the excitation coil.
5. The heating and temperature measuring circuit according to claim 1, wherein,
the induction coil coverage area corresponds to at least a plurality of different locations of the excitation coil coverage area;
the control circuit is used for:
determining a first phase difference of the first electrical signal and the second electrical signal;
correcting the first phase difference according to the amplitude change condition of the third electric signal to obtain a second phase difference;
and determining the temperature of the metal object according to the second phase difference.
6. The heating and temperature measuring circuit according to claim 5, wherein,
the coverage area of the exciting coil comprises a geometric center point and at least one distribution point pair symmetrical based on the geometric center point, and the coverage area of the induction coil at least corresponds to the at least one distribution point pair.
7. The heating and temperature measuring circuit according to claim 1, wherein,
the induction coil comprises a plurality of sub-coils, the third electrical signal comprising a plurality of sub-signals, the plurality of sub-coils corresponding to at least a plurality of different locations of a coverage area of the excitation coil;
the control circuit is used for:
determining a first phase difference of the first electrical signal and the second electrical signal;
correcting the first phase difference according to the plurality of sub-signals to obtain a second phase difference;
and determining the temperature of the metal object according to the second phase difference.
8. The heating and temperature measuring circuit according to claim 7, wherein,
the coverage area of the exciting coil comprises a geometric center point and at least one distribution point pair symmetrical based on the geometric center point, and the plurality of sub-coils at least correspond to the at least one distribution point pair;
the control circuit is used for:
determining the ratio of two sub-signals corresponding to the two sub-coils of the at least one distribution point pair as a compensation value;
and determining a sum of the first phase difference and the compensation value as the second phase difference.
9. The heating and temperature measuring circuit according to claim 7, wherein,
the coverage area of the excitation coil includes a geometric center point, and the plurality of sub-coils are uniformly distributed in a circumferential direction based on the geometric center point.
10. A cooking device, characterized in that it comprises a heating and temperature measuring circuit according to any one of claims 1-9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111542405.4A CN116263358A (en) | 2021-12-13 | 2021-12-13 | Heating temperature measurement circuit and cooking device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111542405.4A CN116263358A (en) | 2021-12-13 | 2021-12-13 | Heating temperature measurement circuit and cooking device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116263358A true CN116263358A (en) | 2023-06-16 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111542405.4A Pending CN116263358A (en) | 2021-12-13 | 2021-12-13 | Heating temperature measurement circuit and cooking device |
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| Country | Link |
|---|---|
| CN (1) | CN116263358A (en) |
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2021
- 2021-12-13 CN CN202111542405.4A patent/CN116263358A/en active Pending
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