CN115435907A

CN115435907A - Temperature measurement circuit and cooking device

Info

Publication number: CN115435907A
Application number: CN202110610779.9A
Authority: CN
Inventors: 马志海; 许志华; 王云峰; 江德勇; 雷俊; 许超; 刘志才; 刘传兰; 郑量; 江太阳
Original assignee: Foshan Shunde Midea Electrical Heating Appliances Manufacturing Co Ltd
Current assignee: Foshan Shunde Midea Electrical Heating Appliances Manufacturing Co Ltd
Priority date: 2021-06-01
Filing date: 2021-06-01
Publication date: 2022-12-06

Abstract

The application discloses provide a temperature measurement circuit and culinary art device. The temperature measurement circuit is arranged in carrying out the scene that heats to the pan, detects the temperature of pan, and the temperature measurement circuit includes: and the resonant circuit inputs a direct current signal. And the excitation circuit is connected with the resonant circuit and is used for controlling the on-off of a direct current path of the resonant circuit so as to enable the resonant circuit to generate a resonant signal. And the sampling circuit is connected with the exciting circuit and is used for sampling the resonance signal to obtain a characteristic signal. The temperature measuring circuit provided by the application has the advantages of high temperature measuring speed, high accuracy and simple measuring mode.

Description

Temperature measurement circuit and cooking device

Technical Field

The application relates to the technical field of household appliances, in particular to a temperature measuring circuit and a cooking device.

Background

Electromagnetic induction heating, induction heating for short, is to utilize magnetic lines of force produced by a coil panel to cut a pot to produce vortex current so as to produce vortex in the heated material, and the joule heat effect of the vortex current enables the pot to be heated, thereby achieving the purpose of heating. Because the electromagnetic induction heating has the advantages of no open fire, environmental protection, safety, energy conservation and the like, the electromagnetic induction heating is more and more favored by consumers and becomes a cooking utensil with high use frequency in the life of people.

In the electromagnetic heating culinary art technique, in order to pursue high intelligent culinary art, generally can select to carry out the temperature measurement to the pan, be convenient for control according to the temperature variation of pan and adjust the culinary art mode, for example, can automatic lifting heating power when detecting the pan temperature reduction for culinary art efficiency.

Generally speaking, a pot temperature measuring system mostly selects to utilize a thermistor on a coil panel to indirectly measure the temperature of a pot through a ceramic panel, and the indirect temperature measurement causes the problems of inaccurate temperature measurement, lagging temperature measurement and the like. If the temperature of the cooker is suddenly cooled down, the induction cooker cannot sense the temperature in time, small firepower heating can still be given, and the cooking efficiency is low.

Disclosure of Invention

The technical problem that this application mainly solved provides a temperature measurement circuit and culinary art device, and the temperature measurement is fast, the accuracy is high to the measuring mode is simple.

A technical scheme that this application adopted provides a temperature measurement circuit, and the temperature measurement circuit is arranged in carrying out the scene that heats to the pan, detects the pan temperature, and the temperature measurement circuit includes: and the resonant circuit inputs a direct current signal. And the excitation circuit is connected with the resonant circuit and is used for controlling the on-off of a direct current path of the resonant circuit so as to enable the resonant circuit to generate a resonant signal. And the sampling circuit is connected with the exciting circuit and is used for sampling the resonance signal to obtain a characteristic signal.

Further, the characteristic signal includes at least one of a resonance voltage amplitude, a resonance frequency, and a resonance period width.

Further, the sampling circuit includes: and the first end of the first resistor is connected with the exciting circuit, and the second end of the first resistor is connected with the processing circuit and used for acquiring the amplitude of the resonant voltage.

Further, the sampling circuit further comprises: and the anode of the first diode is connected with the excitation circuit, and the cathode of the first diode is connected with the first end of the first resistor. And the first end of the second resistor is connected with the second end of the first resistor, and the second end of the second resistor is grounded. And the first end of the first capacitor is connected with the first end of the second resistor, and the second end of the first capacitor is connected with the second end of the second resistor.

Further, the sampling circuit includes: and the sampling coil is arranged corresponding to the resonant circuit and is used for acquiring the resonant frequency or the resonant period width.

Further, the resonant circuit comprises a resonant coil and a resonant capacitor connected in parallel with the resonant coil, and a direct current signal is input to one end of the resonant coil. The excitation circuit includes: the grid electrode of the first power tube inputs a first pulse modulation signal, the source electrode of the first power tube is connected with the other end of the resonance coil and the sampling circuit, and the drain electrode of the first power tube is grounded. The first power tube is configured to be turned on or off according to the first pulse modulation signal, so that the direct current path of the resonant circuit is turned on or off.

Further, the period of the first pulse modulation signal is fixed.

Further, the resonant circuit includes a resonant coil and a resonant capacitor connected in series with the resonant coil. The excitation circuit includes: and a grid electrode of the second power tube inputs a second pulse modulation signal, and a source electrode of the second power tube inputs a direct current signal. And a grid electrode of the third power tube inputs a third pulse modulation signal, a source electrode of the third power tube is respectively connected with a drain electrode of the second power tube and the resonance coil, and the drain electrode of the third power tube is grounded. The second power tube and the third power tube respectively output direct current signals to the resonant circuit under the control of the second pulse modulation signal and the third pulse modulation signal, so that the resonant circuit resonates and generates resonant signals. The second pulse modulation signal and the third pulse modulation signal are inverted.

Further, the periods of the second pulse modulation signal and the third pulse modulation signal are fixed and unchanged.

Further, the temperature measuring circuit includes: and the anode of the second diode inputs an alternating current signal, and the cathode of the second diode is connected with the resonance circuit and used for rectifying the alternating current signal so as to input a direct current signal to the resonance circuit.

In order to solve the above technical problem, another technical solution adopted by the present application is: the utility model provides a cooking device, this cooking device includes the temperature measurement circuit, and this temperature measurement circuit is the temperature measurement circuit that a last technical scheme provided.

The beneficial effect of this application is: be different from prior art, the temperature measurement circuit that this application scheme provided gives resonance circuit input direct current signal to through excitation circuit control resonance circuit direct current route's break-make, so that resonance circuit produces resonance signal, and then utilize sampling circuit to sample resonance signal, obtain characteristic signal, finally utilize processing circuit to confirm the temperature of pan according to characteristic signal. Through this kind of mode, compare with the traditional mode that utilizes temperature sensing subassembly to carry out the temperature measurement to the pan, the temperature of the measurement pan that the mode that the temperature measurement circuit that this scheme of utilization provided carries out the temperature measurement can be timely, accurate.

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 structural diagram of a first embodiment of a temperature measurement circuit provided in the present application;

FIG. 2 is a schematic diagram of a resonant period, a resonant frequency, and a resonant voltage amplitude of a resonant signal;

FIG. 3 is a schematic structural diagram of a second embodiment of a temperature measurement circuit provided in the present application;

FIG. 4 is a schematic circuit diagram of a temperature measuring circuit according to a third embodiment of the present embodiment;

FIG. 5 is a schematic circuit diagram of a fourth embodiment of a temperature measuring circuit provided in this embodiment;

FIG. 6 is a schematic structural diagram of an embodiment of the present application in which a sampling coil and a heating coil are disposed;

FIG. 7 is a schematic circuit diagram of an embodiment of the present application for setting the sampling coil and the heating coil;

FIG. 8 is a schematic structural diagram of another embodiment of the present application in which a sampling coil and a heating coil are arranged;

FIG. 9 is a schematic circuit diagram of another embodiment of the present application;

FIG. 10 is a block diagram schematically illustrating the structure of an embodiment of a cooking apparatus of the present application;

fig. 11 is a schematic flow chart of an embodiment of a pot temperature measuring method provided in this embodiment.

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 merely illustrative of the application and are not limiting of the application. It should be further noted that, for the convenience of description, only some of the structures associated with the present application are shown in the drawings, not all of them. 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.

Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase 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. It is explicitly and implicitly understood by one skilled in the art that the embodiments described herein can be combined with other embodiments.

Generally speaking, in the process of cooking food, water is often added into a pot or food materials are added during cooking, for example, when soup is stewed, various food materials can be added in batches due to different stewing durations of the food materials, or water needs to be added when the condition that water needs to be added occurs, after cold water or food materials are added, the temperature of the pot suddenly decreases, if the temperature change of the pot cannot be detected in time and the firepower is adjusted, the pot needs to be reheated for a longer time under the current firepower, and the consumed time is longer. This embodiment utilizes temperature measurement circuit to take place the resonance, and then in time reflects the temperature variation trend of pan according to resonant signal's resonance cycle width or resonant frequency or the change trend of resonance voltage amplitude, is convenient for control the pan heating according to temperature variation testing result to it is long when sparingly heating, and the testing result is reliable, and sensitivity is high.

The application provides a temperature measurement circuit is arranged in carrying out the scene that heats to the pan, detects the pan temperature, and the heating methods of pan is not injectd to this embodiment, can heat the pan through modes such as electromagnetic heating, electric ceramic heating or electric heating.

The inventor of the application finds that the resonance inductance of the resonance circuit can be mutually coupled with the cookware during resonance, so that when the temperature of the cookware changes, the mutual coupling relation can correspondingly change the inductance and the reflection internal resistance of the resonance inductance, and the inductance and the reflection internal resistance of the resonance inductance can be determined by measuring the resonance frequency, the resonance period width or the voltage amplitude of the resonance inductance or the resonance signal. Therefore, the temperature measuring circuit provided by the embodiment can indirectly determine the temperature of the cookware according to the resonant frequency, the resonant period width or the voltage amplitude.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a first embodiment of a temperature measurement circuit provided in the present application, and as shown in fig. 1, specifically, the temperature measurement circuit 100 includes a resonant circuit 101, an excitation circuit 102, a sampling circuit 103, and a processing circuit 104, which are connected in sequence.

Wherein a dc signal is input to the resonant circuit 101 to power the entire temperature measurement circuit 100. Acting to control the switching on and off of the dc path of the resonant circuit 101 is an excitation circuit 102 to cause the resonant circuit 101 to resonate and generate a resonant signal. Specifically, resonant circuit 101 and the pan cooperation take place the resonance, and then produce the resonance signal along with the change of pan temperature.

The circuit that samples the resonance signal is the sampling circuit 103, and the characteristic signal is obtained. The characteristic signal based processing circuit 104 can determine the temperature of the pot.

In the present embodiment, the characteristic signal includes at least one of a resonance voltage amplitude, a resonance frequency, and a resonance cycle width. Referring to fig. 2, fig. 2 is a schematic diagram of a resonant period, a resonant frequency and a resonant voltage amplitude of a resonant signal, as shown in fig. 2: the maximum value MAX of each resonance signal is the resonance voltage amplitude, the time difference T between two adjacent resonance signals is the resonance period, and the reciprocal f of the resonance period is the resonance frequency.

Resonant frequency calculation formula:

wherein f is frequency in hertz (Hz); l is inductance in Henry (H); c is capacitance in units of farads (F).

The resonant frequency refers to the frequency that may occur in a circuit having a capacitance and an inductance, if they are in parallel, for some small period of time: the voltage of the capacitor is gradually increased, while the current is gradually reduced; the current of the inductor gradually increases, and the voltage of the inductor gradually decreases. And in another very small time period: the voltage of the capacitor is gradually reduced, while the current is gradually increased; the current of the inductor gradually decreases, and the voltage of the inductor gradually increases. The voltage can be increased to a positive maximum value, the voltage can be reduced to a negative maximum value, the direction of the current can also change in the positive and negative directions in the process, the circuit is called to generate electric oscillation, when the sine frequency of the external input voltage of the resonant circuit reaches a certain specific frequency (namely the resonant frequency of the circuit), the inductive reactance and the capacitive reactance of the resonant circuit are equal, Z = R, the resonant circuit is purely resistive outwards, namely resonant. When resonance occurs, the resonant circuit amplifies the input by a factor of Q, Q being the quality factor.

And the resonance period is the inverse of the resonance frequency, namely the calculation formula of the resonance period is as follows:

the resonance voltage amplitude is the maximum absolute value of the resonance signal waveform during one resonance period.

In this embodiment, the process and principle of the resonant circuit 101 generating the resonant signal varying with the temperature of the pot are as follows:

when the excitation circuit 102 controls the conduction of the dc path, power is supplied to the resonant circuit 101, and the resonant inductor converts the electric field energy into magnetic field energy. When the exciting circuit 102 controls the dc path to be disconnected, the resonant inductor (not shown) and the resonant capacitor (not shown) of the resonant circuit 101 resonate to convert the magnetic field energy into the electric field energy, and the pot and the resonant inductor are coupled to each other, so that a resonant signal reflecting the temperature change of the pot can be output.

The temperature measuring circuit 100 provided by this embodiment provides a dc signal to the resonant circuit 101 for supplying power, and controls the on/off of the dc path of the resonant circuit 101 through the exciting circuit 102, so that the resonant circuit 101 resonates and outputs a resonant signal, the resonant signal carries temperature change information of a pot, the resonant signal is further sampled by the sampling circuit 103 to obtain a characteristic signal, and finally, the processing circuit 104 determines the temperature of the pot based on the characteristic signal. Through this kind of mode, compare with the traditional mode that utilizes temperature sensing subassembly to carry out the temperature measurement to the pan, the mode that the temperature measurement circuit 100 that this scheme of utilization provided carries out the temperature measurement can be timely, the temperature of accurate measurement pan.

In one embodiment, the sampling circuit 103 includes a first resistor (not shown), the excitation circuit 102 is connected to a first end of the first resistor, and the processing circuit 104 is connected to a second end of the first resistor for acquiring the resonant voltage amplitude. In fact, the first resistor is connected in series with the resonant circuit 101 to perform a voltage dividing function, and since the voltage variation across the first resistor is the same as the resonance voltage variation, the resonance voltage amplitude can be collected by using the first resistor.

In another embodiment, the sampling circuit 103 further includes a sampling coil (not shown), and the resonant circuit 101 is disposed corresponding to the sampling coil for acquiring the resonant period width or the resonant frequency.

Alternatively, the Processing circuit 104 may be a CPU (Central Processing Unit), and the Processing circuit 104 may be an integrated circuit chip having signal Processing capability. The processing circuit 104 may also be a general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), an off-the-shelf programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.

In a specific embodiment, a manufacturer obtains a table of correspondence between pan temperature and resonant frequency variation, or a table of correspondence between pan temperature and resonant period width variation, or a table of correspondence between pan temperature and resonant voltage amplitude variation, through multiple tests. And then in the actual heating process, the cookware temperature which is changed by the resonance period width change or the resonance voltage amplitude change or the resonance frequency change is obtained according to the correspondence table and the temperature measuring circuit, and the cookware temperature is obtained.

Referring to fig. 3, fig. 3 is a schematic structural diagram of a second embodiment of the temperature measuring circuit provided in the present application, and as shown in fig. 3, the temperature measuring circuit 100 provided in the present embodiment includes a resonant circuit 101, an excitation circuit 102, a sampling circuit 103, a processing circuit 104, and a control circuit 105.

The excitation circuit 102 is connected to the resonance circuit 101, the control circuit 105, and the sampling circuit 103, respectively, and the sampling circuit 103 is connected to the processing circuit 104.

Wherein a dc signal is input to the resonant circuit 101 for supplying power. The exciting circuit 102 is used to control the on and off of the dc path of the resonant circuit 101, so that the resonant circuit 101 outputs a resonant signal with the temperature change of the pot. Specifically, resonant circuit 101 and the pan cooperation take place the resonance, and then produce the resonance signal along with the change of pan temperature.

The output resonance signal is sampled by the sampling circuit 103, and a characteristic signal is obtained. The processing circuit 104 is used for determining the temperature change of the pot based on the characteristic signal.

The control circuit 105 is configured to output a periodic PPG (programmable Pulse Generator) control signal to control on/off of the excitation circuit 102.

The temperature measuring circuit 100 provided in this embodiment inputs a direct current signal to the resonant circuit 101 to supply power, and the control circuit 105 outputs a periodic PPG control signal to control the turn-off and turn-on of the excitation circuit 102, and further controls the turn-off and turn-on of the direct current path of the resonant circuit 101, so that the resonant circuit 101 generates a resonant signal, and further the sampling circuit 103 collects the resonant signal to obtain a characteristic signal, and finally the processing circuit 104 determines the temperature change of the cookware according to the characteristic signal. Through this kind of mode, compare with the traditional mode that utilizes temperature sensing subassembly to carry out the temperature measurement to the pan, the mode that the temperature measurement circuit 100 that this scheme of utilization provided carries out the temperature measurement can be timely, the temperature of accurate measurement pan.

Referring to fig. 4, fig. 4 is a schematic circuit structure diagram of a third embodiment of the temperature measuring circuit 100, as shown in fig. 4, in the temperature measuring circuit 100 provided in this embodiment, a resonant circuit 101 includes a resonant capacitor C1 and a resonant coil L1 connected in parallel with the resonant capacitor C1, and a direct current signal DC is input to one end of the resonant coil L1 to supply power. A pot Pan is placed above the resonant coil L1, so that the resonant circuit 101 is coupled with the pot Pan and generates a resonant signal varying with the temperature variation of the pot Pan when the resonant circuit resonates. Cookware Pan and resonance coil L1 inductive coupling, resonance coil L1, resonance electric capacity C1 resonance, cookware Pan temperature variation time, coupling inductance change to influence resonance signal's resonance cycle width or resonance voltage amplitude or resonant frequency.

Optionally, the temperature measuring circuit 100 includes a second diode D2, wherein the alternating current signal AC is input to an anode of the second diode D2, and the resonant circuit 101 is connected to a cathode of the second diode D2 and is configured to rectify the alternating current signal AC to provide the direct current signal DC meeting the requirement for the resonant circuit 101. It is understood that, according to the practical application scenario, the alternating current signal AC may be rectified by any other feasible rectifying circuit, which is not limited in this respect.

The excitation circuit 102 includes a first power tube Q1, a gate G of the first power tube Q1 is inputted with a first pulse modulation signal PWM1, the other end of the resonant coil L1 and the sampling circuit 103 are connected to a source C of the first power tube Q1, and a drain E of the first power tube Q1 is grounded. The first power transistor Q1 is configured to be turned off or turned on according to the first pulse modulation signal PWM1, and further, a dc path of the resonant circuit 101 is turned on or turned off.

Alternatively, the period of the first pulse modulation signal PWM1 is set to be fixed.

Optionally, the sampling circuit 103 includes a first resistor R1, the source C of the first power transistor Q1 is connected to a first end of the first resistor R1, the processing circuit 104 is connected to a second end of the first resistor R1, and the first resistor R1 is configured to acquire the amplitude of the resonant voltage. Optionally, the sampling circuit 103 may further include a first diode D1, a second resistor R2, and a first capacitor C2, wherein a first end of the first resistor R1 is connected to the source C of the first power transistor Q1 through the first diode D1.

Specifically, the source C of the first power transistor Q1 is connected to the anode of the first diode D1, the first end of the first resistor R1 is connected to the cathode of the first diode D1, the second end of the first resistor R1 is connected to the first end of the second resistor R2, and the second end of the second resistor R2 is grounded. A first end of the second resistor R2 is connected to a first end of the first capacitor C2, and a second end of the second resistor R2 is connected to a second end of the first capacitor C2.

The first capacitor C2 is a filter capacitor for filtering the resonant signal, and the first resistor R1 and the second resistor R2 are voltage dividing resistors for dividing the resonant voltage signal output by the resonant circuit 101.

Because the first resistor R1 and the second resistor R2 are connected in series with the resonant circuit 101, when the resonant circuit 101 resonates and further generates a resonant voltage signal, the first resistor R1 and the second resistor R2 can play a role in voltage division, that is, the voltage change at the two ends of the first resistor R1 and the second resistor R2 is synchronous with the voltage change of the resonant voltage signal, so that the change of the voltage amplitude value at the two ends of the collected first resistor R1 or the second resistor R2 can reflect the change of the resonant voltage amplitude value of the resonant voltage signal.

Optionally, the first power transistor Q1 may be a damped diode IGBT field effect transistor. The period of the first pulse modulation signal PWM1 is set to be constant.

This embodiment provides and designs temperature measurement circuit 100 based on single tube resonant circuit, only needs a power tube just can make resonant circuit 101 resonance and output resonance signal, and then can make the control circuit who controls temperature measurement circuit 100 become simpler, practices thrift the material and reduce cost.

Referring to fig. 5, fig. 5 is a schematic circuit structure diagram of a fourth embodiment of the temperature measuring circuit provided in this embodiment, and as shown in fig. 5, the resonant circuit 101 includes an oscillating capacitor C1 and a resonant coil L1 connected in series with the oscillating capacitor C1. Pan has been placed to resonant coil L1 top to make resonant circuit 101 when taking place the resonance, with Pan Pan cross coupling and produce the resonance signal that changes along with Pan Pan temperature variation.

The driving circuit 102 includes a third power transistor Q3 and a second power transistor Q2.

The second pulse modulation signal PWM2 is input to the gate G of the second power transistor Q2, and the DC signal DC is input to the source C of the second power transistor Q2. A third pulse modulation signal PWM3 is input to a gate G of the third power tube Q3, a source C of the third power tube Q3 is connected to a drain E of the second power tube Q2 and one end of the resonant coil L1, and the drain E of the third power tube Q3 is grounded.

The third power tube Q3 and the second power tube Q2 respectively output a direct current signal DC meeting requirements to the resonant circuit 101 under the control of the third pulse modulation signal PWM3 and the second pulse modulation signal PWM2, so that the resonant circuit 101 resonates and generates a resonant signal, and the resonant signal has a temperature change of the pot Pan.

In the present embodiment, the second pulse modulation signal PWM2 and the third pulse modulation signal PWM3 are inverted. That is, the third pulse modulation signal PWM3 is at a high level during a period in which the second pulse modulation signal PWM2 is at a low level, whereas the third pulse modulation signal PWM3 is at a low level during a period in which the second pulse modulation signal PWM2 is at a high level. This way, it can be guaranteed that the third power tube Q3 and the second power tube Q2 cannot be conducted at the same time, so as to avoid current punch-through caused by simultaneous conduction.

The third power tube Q3 and the second power tube Q2 may be IGBT fets with damping diodes.

Alternatively, the periods of the third pulse modulation signal PWM3 and the second pulse modulation signal PWM2 are fixed.

Optionally, the temperature measuring circuit 100 includes a second diode D2, wherein the alternating current signal AC is input to the anode of the second diode D2, and the exciting circuit 102 is connected to the cathode of the second diode D2, and is configured to rectify the alternating current signal AC to input the direct current signal DC meeting the requirement to the exciting circuit 102. It is understood that the alternating current signal AC may be rectified by any other feasible rectifying circuit according to the practical application scenario, and is not limited in particular herein.

Optionally, the sampling circuit 103 includes a first resistor R1, the other end of the resonant coil L1 is connected to a first end of the first resistor R1, the processing circuit 104 is connected to a second end of the first resistor R1, and the first resistor R1 is configured to acquire the resonant voltage amplitude. Optionally, the sampling circuit 103 may further include a first diode D1, a second resistor R2, and a first capacitor C2, wherein a first end of the first resistor R1 is connected to the other end of the resonant coil L1 through the first diode D1.

Specifically, the other end of the resonant coil L1 is connected to the anode of the first diode D1, the first end of the first resistor R1 is connected to the cathode of the first diode D1, the second end of the first resistor R1 is connected to the first end of the second resistor R2, and the second end of the second resistor R2 is grounded. A first end of the second resistor R2 is connected to a first end of the first capacitor C2, and a second end of the second resistor R2 is connected to a second end of the first capacitor C2.

The temperature measuring circuit 100 is designed based on the half-bridge resonant circuit, so that the temperature measuring circuit 100 has good temperature measuring performance and high temperature measuring efficiency.

Optionally, in the temperature measuring circuit 100 provided in the two embodiments, the sampling circuit 103 may further include a sampling coil L2, and the resonant coil L1 is disposed corresponding to the sampling coil L2 and is used for acquiring a resonant period width or a resonant frequency. Specifically, the sampling coil L2 and the resonant coil L1 are mutually coupled, and then the resonant period width or the resonant frequency is acquired.

In a specific application scenario, please refer to fig. 6 and fig. 7 in combination, in which fig. 6 is a schematic structural diagram of an embodiment of an arrangement method of a sampling coil and a resonant coil according to the present application, and fig. 7 is a schematic circuit structural diagram of the embodiment of the arrangement method of the sampling coil and the resonant coil according to the present application. The sampling coil L2 of the present embodiment is disposed at the center position of the resonance coil L1 to acquire a resonance signal.

Referring to fig. 8 and 9 in combination, fig. 8 is a schematic structural diagram of another embodiment of an arrangement method of a sampling coil and a resonant coil according to the present application, and fig. 9 is a schematic circuit structural diagram of another embodiment of the arrangement method of the sampling coil and the resonant coil according to the present application. The sampling coil L2 of this embodiment is a current transformer, and the sampling coil L2 is sleeved on the lead-out wire of the resonant coil L1 to collect the resonant signal.

Besides the two arrangements, the arrangement of the sampling coil L2 relative to the resonant coil L1 may be other arrangements, which are not limited herein.

Referring to fig. 10, fig. 10 is a schematic block diagram of a cooking device according to an embodiment of the present application. As shown in fig. 10, the cooking apparatus 110 of the present embodiment includes a temperature measuring circuit 100, and the temperature measuring circuit 100 is the temperature measuring circuit provided in any one of the above embodiments.

In some embodiments, the cooking device 110 is a device using electromagnetic induction heating, such as an induction cooker, an IH rice cooker, etc., which can directly generate heat at the bottom of a pot without using open flame or conduction heating, so that the thermal efficiency is greatly improved. The electromagnetic oven is an electric cooking appliance made by utilizing the electromagnetic induction heating principle. The device consists of a high-frequency induction heating coil, a high-frequency power conversion device, a controller, a ferromagnetic material pot bottom cooker and the like.

The induction cooker mainly comprises two parts: firstly, an electronic circuit system (comprising an electromagnetic furnace coil panel, namely the heating coil) capable of generating a high-frequency alternating magnetic field; and the other is a structural shell (containing a furnace panel capable of bearing high temperature and cold and hot shock) for fixing the electronic circuit system and bearing the cookware.

Referring to fig. 11, fig. 11 is a schematic flow chart of an embodiment of a temperature measuring method for a pot, as shown in fig. 11, the temperature measuring method for a pot provided in this embodiment is implemented by using the temperature measuring circuit provided in any of the above embodiments, wherein during temperature measurement, a direct current signal is provided to the temperature measuring circuit. Specifically, the pot temperature measuring method can comprise the following steps:

s201: the pulse modulation signal is input to the temperature measuring circuit to excite the temperature measuring circuit to generate resonance and output a resonance signal which changes along with the temperature of the cooker.

In this embodiment, if the temperature measuring circuit is the temperature measuring circuit provided in the third embodiment, the temperature measuring circuit utilizes single-tube resonance to generate a resonance signal. The temperature measuring circuit comprises a power tube, therefore, under the condition, the control circuit directly provides a pulse modulation signal for the power tube to enable the temperature measuring circuit to work, and then the temperature measuring circuit is matched with a cooker to output a resonance signal.

If the temperature measuring circuit is the one provided in the fourth embodiment, the temperature measuring circuit utilizes half-bridge resonance to generate a resonance signal. That is, the temperature measuring circuit includes at least two power transistors, and therefore, in this case, the control circuit needs to provide at least two pulse modulation signals for the temperature measuring circuit to respectively drive the two power transistors to work, so as to cooperate with the pot to output the resonance signal. Wherein the two pulse modulated signals are in anti-phase.

Optionally, the period of the pulse modulation signal provided by the thermometry circuit is set to be constant.

As for the specific characteristics of the provided pulse modulation signal, such as duty ratio, period or frequency, etc. can be set according to specific application scenarios, and are not limited in detail herein.

S202: a characteristic signal of the resonance signal is acquired.

In this embodiment, the characteristic signal of the resonance signal may include a variation value of a resonance period, a variation value of a resonance frequency, or a variation value of a resonance voltage amplitude of the resonance signal.

S203: and determining the temperature of the cooker according to the characteristic signals.

In this embodiment, the manufacturer obtains a correspondence table of the pot temperature and the change of the resonant frequency, or a correspondence table of the pot temperature and the change of the resonant period width, or a correspondence table of the pot temperature and the change of the resonant voltage amplitude value through a plurality of tests. And then in the actual heating process, the cookware temperature which is changed by the resonance period width change or the resonance voltage amplitude change or the resonance frequency change is obtained according to the correspondence table and the temperature measuring circuit, and the cookware temperature is obtained.

The cookware temperature measuring method provided by the embodiment comprises the steps of inputting a pulse modulation signal to a temperature measuring circuit, exciting the temperature measuring circuit to resonate, outputting a resonance signal changing along with the temperature of cookware, obtaining a characteristic signal of the resonance signal, and determining the temperature of the cookware based on the characteristic signal. In this way, the temperature of the pot can be determined quickly, accurately and efficiently.

In summary, the temperature measurement circuit provided by the application inputs a direct current signal to the resonant circuit to supply power, and controls the turn-off and turn-on of the direct current path of the resonant circuit through the excitation circuit, so that the resonant circuit generates a resonant signal with cookware temperature change information, the sampling circuit is further used for collecting the resonant signal to obtain a characteristic signal, and finally the processing circuit is used for determining the temperature of the cookware based on the characteristic signal. Through this kind of mode, compare with the traditional mode that utilizes temperature sensing subassembly to carry out the temperature measurement to the pan, the temperature of the measurement pan that the mode that the temperature measurement circuit that this scheme of utilization provided carries out the temperature measurement can be timely, accurate.

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.

In the several embodiments provided in the present application, it should be understood that the disclosed method and apparatus may be implemented in other manners. For example, the above-described device embodiments are merely illustrative, and for example, the division of the above modules or units is only one logical functional division, and there may be other divisions when actually implemented, for example, a plurality of units or components may be combined or may be integrated into another system, or some features may be omitted, or not executed.

Claims

1. The utility model provides a temperature measurement circuit, its characterized in that, temperature measurement circuit is arranged in carrying out the scene of heating to the pan, right the temperature of pan detects, temperature measurement circuit includes:

a resonant circuit to which a direct current signal is input;

the excitation circuit is connected with the resonant circuit and is used for controlling the on-off of a direct current path of the resonant circuit so as to enable the resonant circuit to generate a resonant signal;

the sampling circuit is connected with the excitation circuit and is used for sampling the resonance signal to obtain a characteristic signal;

and the processing circuit is connected with the sampling circuit and used for determining the temperature of the cooker according to the characteristic signal.

2. The thermometric circuit of claim 1,

the characteristic signal comprises at least one of a resonance voltage amplitude, a resonance frequency and a resonance period width.

3. The thermometric circuit of claim 2,

the sampling circuit includes:

the first end of the first resistor is connected with the excitation circuit, and the second end of the first resistor is connected with the processing circuit and used for acquiring the amplitude of the resonance voltage.

4. The temperature sensing circuit of claim 3,

the sampling circuit further includes:

the anode of the first diode is connected with the excitation circuit, and the cathode of the first diode is connected with the first end of the first resistor;

a first end of the second resistor is connected with a second end of the first resistor, and a second end of the second resistor is grounded;

and the first end of the first capacitor is connected with the first end of the second resistor, and the second end of the first capacitor is connected with the second end of the second resistor.

5. The thermometric circuit of claim 2,

the sampling circuit includes:

and the sampling coil is arranged corresponding to the resonant circuit and is used for acquiring the resonant frequency or the resonant period width.

6. The thermometric circuit of claim 1,

the resonance circuit comprises a resonance coil and a resonance capacitor connected with the resonance coil in parallel, and the direct current signal is input to one end of the resonance coil;

the excitation circuit includes:

a grid electrode of the first power tube inputs a first pulse modulation signal, a source electrode of the first power tube is connected with the other end of the resonance coil and the sampling circuit, and a drain electrode of the first power tube is grounded;

the first power tube is configured to be turned on or off according to the first pulse modulation signal, so that a direct current path of the resonant circuit is turned on or off.

7. The temperature sensing circuit of claim 6,

the period of the first pulse modulation signal is fixed and unchanged.

8. The temperature sensing circuit of claim 1,

the resonance circuit comprises a resonance coil and a resonance capacitor connected with the resonance coil in series;

the excitation circuit includes:

a grid electrode of the second power tube inputs a second pulse modulation signal, and a source electrode of the second power tube inputs a direct current signal;

a gate of the third power tube inputs a third pulse modulation signal, a source of the third power tube is connected with a drain of the second power tube and the resonance coil, and a drain of the third power tube is grounded;

the second power tube and the third power tube respectively output the direct current signal to the resonant circuit under the control of the second pulse modulation signal and the third pulse modulation signal, so that the resonant circuit resonates and generates the resonant signal;

the second pulse modulation signal and the third pulse modulation signal are in phase opposition.

9. The thermometric circuit of claim 8,

the periods of the second pulse modulation signal and the third pulse modulation signal are fixed and unchanged.

10. The temperature sensing circuit of claim 1,

the temperature measuring circuit comprises:

and the anode of the second diode is used for inputting an alternating current signal, and the cathode of the second diode is connected with the resonant circuit and used for rectifying the alternating current signal so as to input the direct current signal to the resonant circuit.

11. A cooking device, characterized in that it comprises a temperature measuring circuit, which is a temperature measuring circuit according to any one of claims 1-10.