CN213120892U - Topological structure of temperature measuring circuit - Google Patents
Topological structure of temperature measuring circuit Download PDFInfo
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- CN213120892U CN213120892U CN202020782199.9U CN202020782199U CN213120892U CN 213120892 U CN213120892 U CN 213120892U CN 202020782199 U CN202020782199 U CN 202020782199U CN 213120892 U CN213120892 U CN 213120892U
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Abstract
The application discloses topological structure of temperature measurement circuit includes: an excitation coil; a measurement coil, comprising: the first measuring sub-coil is mutually inducted with the exciting coil and the object to be measured; the second measuring sub-coil is mutually inducted with the exciting coil; the homonymous ends of the first measuring sub-coil and the second measuring sub-coil are connected together, and the heteronymous ends are respectively used as output ends of the measuring coils to output measuring signals, so that the temperature of the object to be measured is determined according to the measuring signals and the acquired resonance electrical parameters of the exciting coils. By means of the mode, the temperature of the object to be measured can be determined according to the measuring signal, accurate temperature control is achieved, and the real-time temperature of the object to be measured is accurately measured.
Description
Technical Field
The application relates to the technical field of temperature measurement, in particular to a topological structure of a temperature measurement circuit.
Background
Electromagnetic heating cookers such as induction cookers, electric rice cookers, electric pressure cookers and the like are novel cookers which utilize the electromagnetic induction heating principle to carry out eddy current heating on cookers, have the advantages of high thermal efficiency, convenient use, no gas combustion pollution, safety, sanitation and the like, and are very suitable for modern families.
The Temperature measuring device of the existing electromagnetic heating cooker utilizes an NTC (Negative Temperature Coefficient, thermistor) on a coil panel to indirectly measure the Temperature of a cooker, but the Temperature measuring device has the problems of inaccurate Temperature measurement, lagging Temperature measurement and the like. Because the error of temperature measurement leads to some intelligent culinary art, accurate accuse temperature culinary art, low temperature culinary art, and water boiling be difficult to by the perception scheduling problem.
SUMMERY OF THE UTILITY MODEL
The main technical problem who solves of this application provides a temperature measurement circuit and cooking device, can solve among the prior art electromagnetic heating cooking ware temperature measurement inaccurate, temperature measurement lag scheduling problem.
In order to solve the technical problem, the application adopts a technical scheme that: a topology structure of a thermometric circuit is provided, comprising: an excitation coil and a measurement coil, the measurement coil comprising: the first measuring sub-coil, the exciting coil and the object to be measured are mutually inducted; the second measuring sub-coil and the exciting coil are mutually inducted; the homonymous ends of the first measuring sub-coil and the second measuring sub-coil are connected together, and the heteronymous ends are respectively used as output ends of the measuring coils to output measuring signals, so that the temperature of the object to be measured is determined according to the measuring signals and the acquired resonance electrical parameters of the exciting coils.
The beneficial effect of this application is: the topological structure of the temperature measuring circuit comprises an exciting coil and a measuring coil; the measuring coil can comprise a first measuring sub-coil and a second measuring sub-coil which are connected with the same-name end, the first measuring sub-coil can be mutually inducted with the exciting coil and the object to be measured with temperature respectively, and the second measuring sub-coil can be mutually inducted with the exciting coil so as to offset the mutual induction of the first measuring sub-coil and the exciting coil; the temperature of the object to be measured is determined by outputting a measurement signal through the output end of the measurement coil and acquiring the resonance electrical parameter of the excitation coil. The temperature of the object to be measured is obtained in the above mode, and the temperature of the object to be measured can be accurately detected in real time, so that accurate temperature control is realized.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts. Wherein:
FIG. 1 is a schematic circuit diagram of an embodiment of a temperature measurement circuit of the present application;
FIG. 2 is a schematic diagram of the temperature measurement circuit and heating of an object to be measured;
FIG. 3 is an equivalent model diagram of an embodiment of the temperature measurement circuit of the present application;
FIG. 4 is a waveform diagram of the present application measured voltage and resonance acquisition voltage;
FIG. 5 is a schematic diagram of a topology of an embodiment of a temperature measurement circuit of the present application;
FIG. 6 is a schematic view of a topology of another embodiment of a temperature measurement circuit of the present application;
FIG. 7 is a schematic view of a topology of another embodiment of a temperature measurement circuit of the present application;
FIG. 8 is a schematic view of a topology of yet another embodiment of a temperature measurement circuit of the present application;
FIG. 9 is a schematic circuit diagram of another embodiment of the thermometry circuit of the present application;
FIG. 10 is a schematic structural diagram of a temperature measurement circuit according to another embodiment of the present application;
FIG. 11 is a schematic structural diagram of an embodiment of a coil arrangement in a temperature measurement circuit according to the present application;
FIG. 12 is a schematic structural diagram of another embodiment of a coil arrangement in a temperature measurement circuit according to the present application;
FIG. 13 is a schematic structural view of a second measurement sub-coil and sampling coil winding embodiment of the present application;
FIG. 14 is a schematic structural diagram of another embodiment of the coil arrangement in the temperature measuring circuit of 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, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
The application provides a topological structure of temperature measurement circuit, and this temperature measurement circuit has the temperature measurement function, can be arranged in any kind of equipment to realize accurate accuse temperature, and coupling coil arranges in the temperature measurement circuit can be carried out better to this application. For convenience of explanation, the following description is made of a topology structure in which the temperature measuring circuit is used in the cooking device.
Referring to fig. 1 and fig. 2, fig. 1 is a schematic circuit diagram of a temperature measurement circuit according to an embodiment of the present application, and fig. 2 is a schematic heating diagram of the temperature measurement circuit and an object to be measured. The temperature measuring circuit 100 in this embodiment may include an excitation coil L1 and a measurement coil 120. The measuring coil 120 may include a first measuring sub-coil L2 and a second measuring sub-coil L3.
The first measuring sub-coil L2 may be mutually inductive with the exciting coil L1 and the object to be temperature measured 200, respectively, and the second measuring sub-coil L3 may be mutually inductive with the exciting coil L1.
One pair of homonymous ends of the first measuring sub-coil L2 and the second measuring sub-coil L3 are connected, and the other pair of homonymous ends of the first measuring sub-coil L2 and the second measuring sub-coil L3 are used as output ends of the measuring coil 120 to output measuring signals, so that the temperature of the object 200 to be measured is determined by the measuring signals and the acquired resonance electrical parameters of the exciting coil L1.
Further, the excitation coil L1 may be a heating coil L1, the heating coil L1 and the resonance capacitor Cp may constitute a resonance circuit 110, and the resonance circuit 110 may be used for resonance heating of the object 200 to be temperature measured.
For example, the heating coil L1 and the resonant capacitor Cp may invert to generate a high frequency oscillation source of 15KHz to 60KHz, radiate a magnetic field, and form an eddy current at the bottom of the object 200 to be heated for electromagnetic induction heating. The object to be measured 200 may be various cookers.
Among them, the first measuring sub-coil L2 may be disposed close to the heating coil L1. The first and second measuring sub-coils L2 and L3 form a differential coil, one pair of the same-name terminals of the two are connected together (as marked by x in fig. 1), and the other pair of the same-name terminals serve as the output terminals of the measuring coil 120 to output a measuring signal, so that the temperature of the object to be measured is determined by the measuring signal and the collected resonance electrical parameters of the heating coil L1. Alternatively, it is also possible to determine a thermal resistance parameter of the object to be temperature-measured by measuring the signal and the acquired resonance electrical parameter of the heating coil L1, and determine the temperature of the object to be temperature-measured based on the thermal resistance parameter.
In some embodiments, the second measuring sub-coil L3 may be wound on the magnetic conductor with the resonant tank in which the heating coil L1 is located passing through the magnetic conductor, thereby mutually inducing the second measuring sub-coil L3 to the heating coil L1.
The second measuring sub-coil L3 may be used to generate mutual inductance with the heating coil L1 so as to cancel out the mutual inductance generated by the first measuring sub-coil L2 and the heating coil L1, and thus it is required that the second measuring sub-coil L3 does not mutually interact with the object to be warmed 200 and interferes with the magnetic field far away from the heating coil L1.
The first measuring sub-coil L2 can be regarded as a thermal resistance sampling coil of the object 200 to be measured in temperature. The heating coil L1 converts the object 200 to be temperature-measured into electric energy in the form of a magnetic field and further into heat energy for resonance heating. In the case of performing the resonance heating, the object 200 to be heated, such as various cookers, may be equivalent to a circuit composed of an induction inductor and a thermal resistor, wherein the induction inductor and the heating coil L1 are mutually induced to generate a corresponding induction current, and the induction current flows through the thermal resistor to convert electric energy into heat energy for heating.
It should be noted that the excitation coil L1 is only one embodiment of the present application, and in other embodiments, the excitation coil L1 may be a coil other than a heating coil to achieve other functions. The type of the excitation coil L1 can be selected by those skilled in the art according to actual products, and will not be described in detail herein.
With continued reference to FIG. 1, the thermometric circuit 100 may further include a sampling coil L4, and in some embodiments, the sampling coil L4 is wound around a magnetizer through which the resonant loop 110 of the heating coil L1 passes to allow the sampling coil L4 to mutually induce the heating coil L1 to acquire the resonant electrical parameter of the heating coil L1. The sampling coil L4 may be a high-frequency signal transformer of the heating coil L1, and samples the resonant current flowing through the heating coil L1 in the form of high-frequency mutual inductance. The resonant electrical parameter may be a resonant current flowing through the resonant tank 110.
Referring to fig. 1 and fig. 3 together, fig. 3 is an equivalent model diagram of an embodiment of the temperature measuring circuit of the present application. In this embodiment, the object 200 to be measured includes an inductive inductance Lr and an equivalent thermal resistance Rz.
As shown in FIG. 3, when the heating coil L1 performs resonance heating, the resonance current I1Flows through the resonant circuit 110 in which the heating coil L1 is located, and the sampling coil L4 induces the resonant circuit I flowing through the heating coil L11And generates a corresponding resonant acquisition voltage U1. The measurement voltage output by the measurement coil 120 (including the measurement voltages of the first and second measurement sub-coils L2 and L3) is designated U2.
When the object 200 to be measured in temperature is placed on the heating coil L1, the heating coil L1 and the induction inductor Lr in the object 200 to be measured in temperature mutually induce, thereby generating a corresponding induction current Ir, wherein the induction current Ir flows through the induction inductor Lr and the equivalent thermal resistance Rz.
The heating coil L1 and the induction inductor Lr in the object 200 to be measured generate mutual inductance M1rThen it satisfies the following formula:
in the present application, the second measuring sub-coil L3 of the measuring coils 120 is mutually induced with the heating coil L1, and the first measuring sub-coil L2 is mutually induced with the heating coil L1 and the object to be measured temperature 200, respectively. Therefore, as shown in fig. 3, the inductive inductance Lr of the object to be measured 200 and the first measuring sub-coil L2 generate a mutual inductance Mr2But not mutually induct with L3; the heating coil L1 and the second measuring sub-coil L3 generate mutual inductance M13And generates mutual inductance M with the first measuring sub-coil L212。
For the convenience of subsequent calculations, the measurement coil 120 may be corrected in advance: the measuring coil 120 makes the voltage difference between the two output terminals a preset value when the object to be measured 200 is not placed on the heating unit 110, thereby completing the correction. Alternatively, the preset value may be 0, so as to complete the return-to-zero correction, such that the measurement voltage U2 output by the measurement coil 120 is caused only by the mutual inductance Mr2 between the first measurement sub-coil L2 and the inductive inductance Lr of the object to be temperature measured 200. The corrected voltage difference between the two output terminals is 0 for the following example.
Specifically, when the object 200 to be measured is placed, the inductive inductor Lr generates a mutual inductance M with respect to the first measuring sub-coil L2r2(ii) a When the object 200 to be measured is not placed, the inductive inductor Lr does not generate mutual inductance M on the first measuring sub-coil L2r2Therefore, when the object to be measured for temperature 200 is not placed on the heating coil L1, the voltage difference between the two output terminals of the measuring coil 120 is made 0, thereby zeroing the correcting measuring coil 120. At this time, the voltage difference between the synonym terminals of the first and second measuring sub-coils L2 and L3 is close to 0, i.e., j ω M13＝jωM12To zero-correct the first and second measuring sub-coils L2 and L3, that is, to make the initial U2 equal to 0.
When the object 200 to be measured is placed on the heating coil L1, the induction inductance Lr of the object 200 to be measured mutually generates mutual inductance to the first measuring sub-coil L2Sensing Mr2 without producing mutual inductance to the second measurement sub-coil L3; and the mutual inductance M of the heating coil L1 to the first measuring sub-coil L212And mutual inductance M for the second measurement sub-coil L313After return-to-zero correction, satisfies j omega M13＝jωM12(ii) a Therefore, the measurement voltage U2 output by the measurement coil 120 is generated only by the mutual inductance Mr2 generated by the inductive inductance Lr of the object 200 to be temperature measured to the first measurement sub-coil L2, that is:
U2＝(jωMr2)Ir (2)
in other words, after the return-to-zero correction of the measuring coil 120, the mutual inductance M generated between the second measuring sub-coil L3 and the heating coil L113The mutual inductance M of the heating coil L1 to the first measuring sub-coil L2 is cancelled12Therefore, the measurement voltage outputted by the subsequent measurement coil 120 is generated only due to the mutual inductance Mr2 generated by the inductive inductance Lr of the object 200 to be temperature measured to the first measurement sub-coil L2.
Therefore, by substituting the above formula (1) into the formula (2), it can be seen that
In the formula (3), the resonance current I1Can be measured by a sampling coil L4, specifically, U1 is I1Therefore, the resonant current I can be obtained by sampling the resonant acquisition voltage U1 output by the coil L41(ii) a U2 is the measurement voltage output by the measurement coil 120. After the inductance values of the heating coil L1, the first measuring sub-coil L2, the second measuring sub-coil L3, the sampling coil L4 and the inductance Lr are determined and their mutual positions are determined, then M1r，Mr2May also be determined. Therefore, the magnitude of the thermal resistance Rz of the object 200 to be measured can be calculated by the above formula (3).
Since Lr is an induction inductance of the object 200 to be measured, the object 200 to be measured is generally a cookware for cooking, and the temperature coefficient of the induction inductance Lr is small; the equivalent thermal resistance Rz has a large temperature coefficient, and most stainless steel or iron materials have a temperature coefficient of 0.001-0.007 (20 ℃), so that the equivalent thermal resistance Rz is equal to the temperature coefficient of the equivalent thermal resistance RzU2 and I were measured1The thermal resistance Rz of the object 200 to be measured can be derived, and then the temperature of the object 200 to be measured can be obtained according to the preset thermal resistance-temperature function T ═ f (Rz).
Therefore, in the present embodiment, the thermal resistance parameter of the object 200 to be measured is accurately obtained by detecting the mutual inductance between the measuring coil 120, the object 200 to be measured and the heating coil L1, so that the temperature measuring circuit 100 of the present embodiment can accurately measure the real-time temperature of the object 200 to be measured while heating. When the temperature measuring circuit 100 of the present embodiment is applied to a cooking device, it can realize intelligent cooking operations such as precise temperature control cooking, low-temperature cooking, accurate sensing of water boiling in the cooking device, and the like.
In addition, for the data processing in the temperature measurement circuit 100, it can be known from the formula (3) that the equivalent thermal resistance Rz of the object 200 to be measured can be determined according to the measurement voltage U2 and the resonance acquisition voltage U1, and the temperature of the object 200 to be measured can be determined according to the equivalent thermal resistance Rz.
For example, waveforms of the voltage U1 and the measurement voltage U2 are acquired by high-speed AD sampling resonance, stored in a memory, and then subjected to data processing. Since the resonant collection voltage U1 and the measurement voltage U2 are alternating currents and it can be seen from formula (3) that the measurement voltage U2 is a non-standard function, the values of the resonant collection voltage U1 and the measurement voltage U2 cannot be directly obtained. It is also necessary to perform digital signal processing on its waveform, such as DFT (Discrete Fourier Transform) processing, including:
selecting a finite discrete frequency sequence with the length of M (1-10) and analyzing the Nth trigonometric function U2N＝CV2N*cos(ωNt+ΦV2N) (ii) a Similarly, M-length finite discrete frequency sequences are selected from U1, and the Nth trigonometric function U is analyzed1N＝CV1N*sin(ωNt+ΦV1N)。
Due to U2NAnd U1NThe excitation sources are the same, the discrete frequency points are selected to be the same, so the frequencies of the two are the same, namely, the frequency is omegaNt；CV2NAnd CV1NIs U2NAnd U1NThe amplitude value. Thus, calculate U1NAnd U2NThe phase difference Δ Φ of (a) can be indirectly related to Rz without comparing the specific values of the measurement voltage U2 and the resonance acquisition voltage U1. In addition, in order to reduce the interference factor, it is preferable to select the fundamental waves of U1 and U2 as comparison objects.
Specifically, the phase difference Δ Φ may be obtained in the following manner:
1) and acquiring the ratio of the measurement voltage U2 to the resonance acquisition voltage U1, and performing inverse tangent function operation on the ratio to obtain the phase difference between the measurement voltage U2 and the resonance acquisition voltage U1. Such as the formula: tan (phi)V2N-ΦV1N)＝CV2N*cos(ωNt+ΦV2N)/CV1N*sin(ωN t+ΦV1N) I.e. to obtain tan (phi)V1N-ΦV2N) Obtaining delta phi as phi by inverse tangent function arctanV1N-ΦV2N。
2) The waveforms of the measurement voltage U2 and the resonance acquisition voltage U1 are compared to obtain a phase difference between the measurement voltage U2 and the resonance acquisition voltage U1. Fig. 4 is a waveform diagram of the measurement voltage and the resonance acquisition voltage according to the present application, as shown in fig. 4. By U1NStarting from the voltage waveform a, recording U2NThe time delta phi required by the voltage to arrive at point b is the phase difference, wherein points a and b are at the same voltage value.
3) The measured voltage U2 and the resonance collection voltage U1 are compared by a comparator to obtain a phase difference between the measured voltage U2 and the resonance collection voltage U1. For example, will U1NAnd U2NOutput through I/O interface of U1 in U1NAnd U2NAnd the positive and negative input ends of the comparator are connected into the comparator, so that the phase difference delta phi is obtained.
In addition, those skilled in the art may also obtain the phase difference Δ Φ by using other methods, which are not described in detail herein. After the phase difference delta phi is obtained, measuring delta phi corresponding to the thermal resistance Rz at the temperature of (-50-400 ℃), and establishing a relation of the two, namely T-f (delta phi). In practical use, the temperature of the object 200 to be measured can be obtained by looking up the table or the relationship between the table and the object.
In order to realize the temperature measuring circuit, the application provides various topological structures corresponding to the temperature measuring circuit, and specifically, the topological structures can include the following structures:
referring to fig. 5 and 6, fig. 5 is a schematic view of a topology structure of an embodiment of a temperature measuring circuit according to the present application; FIG. 6 is a schematic view of a topology of another embodiment of a temperature measurement circuit of the present application.
The resonant capacitor Cp may be connected in series with the heating coil L1 to form the resonant tank 110 such that the resonant tank 110 includes a first region a, a second region B, and a third region D. Wherein the first region a may include a first connection line B connected to a first end of the heating coil L1, the second region B includes a second connection line c connected between a second end of the heating coil L1 and a first end of the resonance capacitance Cp, and the third region D includes a third connection line D connected to a second end of the resonance capacitance Cp.
Wherein the second measuring sub-coil L3 and/or the sampling coil L4 may be disposed on at least one of the first connection line B in the first region a, the second connection line C in the second region B, and the third connection line d of the third region C. That is, the second measuring sub-coil L3 and the sampling coil L4 may be disposed on a connection line of the same region, for example, as shown in fig. 5, the second measuring sub-coil L3 and the sampling coil L4 may be disposed on the first connection line b of the first region a; alternatively, the second measuring sub-coil L3 and the sampling coil L4 may be provided on different connection lines, for example, as shown in fig. 6, the second measuring sub-coil L3 is provided on the first connection line B of the first region a, and the sampling coil L4 is provided on the second connection line c of the second region B. Preferably, the second measuring sub-coil L3 and/or the sampling coil L4 are disposed in the same region, which may make the temperature measurement more accurate.
Referring to fig. 7 and 8, fig. 7 is a schematic view of a topology structure of a temperature measuring circuit according to another embodiment of the present application; FIG. 8 is a schematic view of a topology of a temperature measurement circuit according to another embodiment of the present application.
In the present embodiment, the resonant capacitor Cp may be connected in parallel with the heating coil L1 to form the resonant tank 110, such that the resonant tank 110 includes a first region F, a second region E, a third region G and a fourth region H.
Wherein the first region F may include a first connection line F connected between a first end of the heating coil L1 and a first end of the resonance capacitance Cp, the second region E may include a second connection line E connecting the first connection line and the first end of the resonance capacitance Cp, the third region G may include a third connection line G connected between a second end of the heating coil L1 and a second end of the resonance capacitance Cp, and the fourth region H may include a fourth connection line H connecting the third connection line and the second end of the resonance capacitance Cp.
The second measuring sub-coil L3 and/or the sampling coil L4 may be disposed on at least one of the first connection line F in the first region F, the second connection line E in the second region E, the third connection line G in the third region G, and the fourth connection line H in the fourth region H. That is, the second measuring sub-coil L3 and the sampling coil L4 may be provided on a connection line of the same region, for example, as shown in fig. 7, the second measuring sub-coil L3 and the sampling coil L4 are provided on the first connection line F of the first region F; the second measuring sub-coil L3 and the sampling coil L4 may be disposed on a connection line of different regions, for example, as shown in fig. 8, the second measuring sub-coil L3 may be disposed on the first connection line F of the first region F, and the sampling coil L4 may be disposed on the third connection line G of the third region G. Preferably, the second measuring sub-coil L3 and/or the sampling coil L4 are disposed in the same region, which may make the temperature measurement more accurate.
Furthermore, in some embodiments, the sampling coil L4 may be replaced with a resistive sampling unit 130. Referring to fig. 9, fig. 9 is a circuit diagram of another embodiment of the temperature measuring circuit of the present application. The present embodiment includes a resistance sampling unit 130. The resonant capacitor Cp may be connected in parallel with the heating coil L1 to form the resonant tank 110 such that the resonant tank 110 includes a first region F, a second region E, a third region G, and a fourth region H.
The resistance sampling unit 130 may be used to acquire resonant electrical parameters of the heating coil L1. The resistance sampling unit 130 may include a power switch Q1 and a sampling resistor R1. The power switch Q1 may include a control terminal, a first path terminal, and a second path terminal. Wherein the control terminal is used for receiving the resonant frequency signal, and the first path terminal can be connected to the resonant tank 110. One end of the sampling resistor R1 may be connected to the second path terminal of the power switch Q2, and the other end of the sampling resistor R1 may be grounded. Wherein, a node between the sampling resistor R1 and the second path terminal of the power switch Q1 may be used as the output terminal a of the resistance sampling unit 130 to output the acquired resonant electrical parameter of the heating coil L1.
In the present embodiment, the second measuring sub-coil L3 may be disposed on a connection line of any one of the regions E, F, G, H as shown in fig. 9. In addition, it will be understood by those skilled in the art that the resistance sampling unit 130 may also be applied to the resonant capacitor Cp which may be connected in series with the heating coil L1 to form the resonant tank 110, so as to acquire the resonant electrical parameters of the heating coil L1. The position of the resistance sampling unit 130 is not limited as long as it is connected to the resonant tank 110.
Further, please refer to fig. 10, fig. 10 is a schematic structural diagram of a temperature measuring circuit according to another embodiment of the present application. In this embodiment, the temperature measuring circuit 100 may further include a first signal processing unit 141, a second signal processing unit 142, and a main control chip 150.
The first signal processing unit 141 may be connected to an output terminal of the measuring coil 120 to sample the measuring signal, and the second signal processing unit 142 may be connected to an output terminal of the sampling coil L4 or the resistance sampling unit 130 to sample the resonance electrical parameter; the main control chip 150 may be connected to the first signal processing unit 141 and the second signal processing unit 142 to determine a thermal resistance parameter of the object to be measured by measuring the signal and the resonance electrical parameter, and determine the temperature of the object to be measured according to the thermal resistance parameter.
The first signal processing unit 141 and the second signal processing unit 142 may include processing circuits, such as a follower, an operational amplifier circuit, a comparison circuit, and the like, and the first signal processing unit 141 and the second signal processing unit 142 may convert the acquired analog signals into digital signals and input the digital signals to the main control chip 150. The specific principles and steps have been introduced in the above embodiments and will not be described in detail here.
Further, in order to fully utilize the space for arrangement of the temperature measuring circuit, the coil position arrangement in the temperature measuring circuit 100 may be set. Specifically, please refer to fig. 11 to 14, fig. 11 is a schematic structural diagram of an embodiment of a coil arrangement in a temperature measuring circuit according to the present application; FIG. 12 is a schematic structural diagram of another embodiment of a coil arrangement in a temperature measurement circuit according to the present application; FIG. 13 is a schematic structural view of a second measurement sub-coil and sampling coil winding embodiment of the present application; FIG. 14 is a schematic structural diagram of another embodiment of the coil arrangement in the temperature measuring circuit of the present application.
In fig. 11 and 12, a heating coil L1 is provided in an electric control board, and a first measuring sub-coil L2 may be placed over a middle region of a disc surface of the heating coil at a predetermined angle, wherein the predetermined angle may be in a range of 0 to 45 degrees.
The second measuring sub-coil L3 and the sampling coil L4 may be provided away from the heating coil, and preferably both may be fixed on the control circuit board 170 near the heating coil L1, wherein the control circuit board 170 may be a PCB. The current flowing through the resonant tank 110 may pass through the second measuring sub-coil L3 and the sampling coil L4 to avoid interference of the object 200 to be temperature-measured with the second measuring sub-coil L3 and the sampling coil L4.
When the second measuring sub-coil L3 and the sampling coil L4 are adjacently arranged, the iron core 161 of the second measuring sub-coil L3 and the iron core 162 of the sampling coil L4 can be separately arranged (as shown in fig. 11), that is, the second measuring sub-coil L3 and the sampling coil L4 are two independent coils. Alternatively, the second measuring sub-coil L3 and the sampling coil L4 may be wound around the same core 160 (as shown in fig. 12 and 13).
In some embodiments, a second measuring sub-coil L3 may also be disposed below the first measuring sub-coil L2, as shown in fig. 14. The heating coil L1 may include a plurality of heater sub-coils L1.1, and each two adjacent heater sub-coils L1.1 may be connected together by a heating connection line. The first measuring sub-coil L2 may be disposed at a middle region of the heating coil L1, the second measuring sub-coil L3 may be disposed below the first measuring sub-coil L1, and the second measuring sub-coil L3 may be disposed on any one of the heating connection lines, thereby avoiding interference of the object to be measured in temperature 200 with the second measuring sub-coil L3.
The above description is only for the purpose of illustrating embodiments of the present application and is not intended to limit the scope of the present application, and all modifications of equivalent structures and equivalent processes, which are made by the contents of the specification and the drawings of the present application or are directly or indirectly applied to other related technical fields, are also included in the scope of the present application.
Claims (11)
1. A topological structure of a thermometric circuit, comprising:
an excitation coil;
a measurement coil, comprising:
the first measuring sub-coil is mutually inducted with the exciting coil and the object to be measured;
a second measurement sub-coil mutually inductive with the excitation coil;
the temperature measuring device comprises a first measuring sub-coil, a second measuring sub-coil, a first exciting coil, a second exciting coil and a second measuring sub-coil, wherein one pair of same-name ends of the first measuring sub-coil and the second measuring sub-coil are connected, and the other pair of same-name ends of the first measuring sub-coil and the second measuring sub-coil are used as output ends of the measuring coils to output measuring signals, so that the temperature of an object to be measured is determined according to the measuring signals and the acquired resonance electrical parameters of the exciting coils.
2. The thermometric circuit topology of claim 1, wherein said excitation coil is a heating coil; and the resonance capacitor and the heating coil form a resonance loop for performing resonance heating on the object to be measured.
3. The thermometric circuit topology of claim 2, further comprising:
and the sampling coil is used for acquiring the resonance electric parameters of the heating coil.
4. The thermometric circuit topology of claim 3, wherein the resonant capacitor and the heating coil are connected in series to form the resonant tank, such that the resonant tank comprises a first region, a second region and a third region, wherein the first region comprises a first connecting line connecting the first end of the heating coil, the second region comprises a second connecting line connecting the second end of the heating coil and the first end of the resonant capacitor, and the third region comprises a third connecting line connecting the second end of the resonant capacitor;
wherein the second measurement sub-coil and/or the sampling coil is disposed on at least one of the first connection line in the first region, the second connection line in the second region, and the third connection line in the third region.
5. The thermometric circuit topology of claim 3, wherein the resonant capacitor is connected in parallel with the heating coil to form the resonant tank such that the resonant tank comprises a first region, a second region, a third region and a fourth region, wherein the first region comprises a first connection line connected between a first end of the heating coil and a first end of the resonant capacitor, the second region comprises a second connection line connecting the first connection line and a first end of the resonant capacitor, the third region comprises a third connection line connected between a second end of the heating coil and a second end of the resonant capacitor, and the fourth region comprises a fourth connection line connecting the third connection line and a second end of the resonant capacitor;
wherein the second measurement sub-coil and/or the sampling coil is disposed on at least one of the first connection line in the first region, the second connection line in the second region, the third connection line in the third region, and the fourth connection line in the fourth region.
6. The thermometric circuit topology of claim 3, wherein the second measurement sub-coil and/or the sampling coil is disposed on a control circuit board.
7. The thermometric circuit topology of claim 2, further comprising:
a resistance sampling unit for collecting the resonant electrical parameters of the heating coil, wherein the resistance sampling unit comprises:
a power switch including a control terminal, a first path terminal and a second path terminal, wherein the control terminal is used for receiving a resonant frequency signal, and the first path terminal is connected to the resonant tank;
and one end of the sampling resistor is connected with the second path end of the power switch, and the other end of the sampling resistor is grounded, wherein a node between the sampling resistor and the second path end of the power switch is used as an output end of the resistor sampling unit so as to output the acquired resonance electric parameters of the heating coil.
8. The thermometric circuit topology of any of claims 3-6, further comprising:
a first signal processing unit connected to the output of the measuring coil to sample the measuring signal;
and the second signal processing unit is connected with the output end of the sampling coil so as to sample the resonance electric parameters.
9. The thermometric circuit topology of claim 8, further comprising:
and the main control chip is connected with the first signal processing unit and the second signal processing unit so as to determine the thermal resistance parameter of the object to be measured by the measuring signal and the resonance electrical parameter and determine the temperature of the object to be measured according to the thermal resistance parameter.
10. The topology structure of temperature measuring circuit according to claim 2, wherein the first measuring sub-coil is placed on the middle area of the disk surface of the heating coil at a predetermined angle, and the predetermined angle is in the range of 0-45 degrees.
11. The topology of thermometric circuit of claim 2, wherein said heating coil comprises a plurality of heater sub-coils, each two adjacent said heater sub-coils being connected together by a heating connection line, wherein said second measurement sub-coil is disposed on any of said heating connection lines.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| WO2021228116A1 (en) * | 2020-05-12 | 2021-11-18 | 佛山市顺德区美的电热电器制造有限公司 | Heating circuit and cooking apparatus |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| WO2021228116A1 (en) * | 2020-05-12 | 2021-11-18 | 佛山市顺德区美的电热电器制造有限公司 | Heating circuit and cooking apparatus |
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