CN115435907A - A temperature measuring circuit and cooking device - Google Patents

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

A temperature measuring circuit and cooking device

technical field

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

Background technique

Electromagnetic induction heating, referred to as induction heating, is to use the magnetic field line generated by the coil plate to cut the pot to generate eddy current to generate eddy current inside the heated material, and the Joule heating effect of the eddy current to heat up the pot to achieve the purpose of heating. Because electromagnetic induction heating has the advantages of no open flame, environmental protection, safety, energy saving, etc., it is more and more favored by consumers, and has become a cooking utensil that is frequently used in people's lives.

In electromagnetic heating cooking technology, in order to pursue highly intelligent cooking, it is generally chosen to measure the temperature of the pot, so as to control and adjust the cooking mode according to the temperature change of the pot. For example, when the temperature of the pot is detected to drop, it can automatically Increase heating power to speed up cooking efficiency.

Generally speaking, most pot temperature measurement systems choose to use the thermistor on the coil plate to measure the pot indirectly through the ceramic panel. Because of the indirect temperature measurement, there are problems such as inaccurate temperature measurement and temperature measurement lag. If the temperature of the pot suddenly cools down, the induction cooker will not be able to sense it in time, and it may still be heated with a small fire, and the cooking efficiency is low.

Contents of the invention

The technical problem mainly solved by the application is to provide a temperature measuring circuit and a cooking device, which have fast temperature measurement speed, high accuracy and simple measurement method.

A technical solution adopted in this application is to provide a temperature measuring circuit, which is used to detect the temperature of the pot in the scene of heating the pot. The temperature measuring circuit includes: a resonant circuit, and the resonant circuit inputs a DC Signal. The excitation circuit is connected with the resonant circuit, and is used to control the on-off of the direct current path of the resonant circuit, so that the resonant circuit generates a resonant signal. The sampling circuit is connected with the excitation circuit and is used for sampling the resonance signal to obtain the characteristic signal.

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

Further, the sampling circuit includes: a first resistor, the first end of the first resistor is connected to the excitation circuit, and the second end of the first resistor is connected to the processing circuit for collecting the amplitude of the resonance voltage.

Further, the sampling circuit further includes: a first diode, the anode of the first diode is connected to the excitation circuit, and the cathode of the first diode is connected to the first end of the first resistor. The second resistor, the first end of the second resistor is connected to the second end of the first resistor, and the second end of the second resistor is grounded. The first capacitor, the first end of the first capacitor is connected to the first end of the second resistor, and the second end of the first capacitor is connected to the second end of the second resistor.

Further, the sampling circuit includes: a sampling coil, which is set corresponding to the resonant circuit, and is used to collect the resonant frequency or the width of the resonant period.

Further, the resonant circuit includes a resonant coil and a resonant capacitor connected in parallel with the resonant coil, and a DC signal is input to one end of the resonant coil. The exciting circuit includes: a first power tube, the gate of the first power tube inputs the first pulse modulation signal, the source of the first power tube is connected to the other end of the resonant coil and the sampling circuit, and the drain of the first power tube is grounded. Wherein, the first power tube is configured to be turned on or off according to the first pulse modulation signal, so as to turn on or turn off the DC path of the resonant circuit.

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: a second power tube, the gate of the second power tube inputs a second pulse modulation signal, and the source of the second power tube inputs a direct current signal. The third power tube, the gate of the third power tube inputs the third pulse modulation signal, the source of the third power tube is respectively connected with the drain of the second power tube and the resonant coil, and the drain of the third power tube is grounded. Wherein, the second power tube and the third power tube output DC signals to the resonant circuit under the control of the second pulse modulation signal and the third pulse modulation signal respectively, so that the resonant circuit resonates and generates a resonance signal. The phases of the second pulse modulation signal and the third pulse modulation signal are inverted.

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

Further, the temperature measurement circuit includes: a second diode, the anode of the second diode inputs an AC signal, and the cathode of the second diode is connected to a resonant circuit for rectifying the AC signal to input a DC signal to the resonance circuit.

In order to solve the above technical problems, another technical solution adopted by the present application is to provide a cooking device, which includes a temperature measuring circuit, and the temperature measuring circuit is the temperature measuring circuit provided in the previous technical solution.

The beneficial effects of the present application are: different from the prior art, the temperature measuring circuit provided by the present application inputs a DC signal to the resonant circuit, and controls the on-off of the DC path of the resonant circuit through the excitation circuit, so that the resonant circuit generates a resonant signal, and then A sampling circuit is used to sample the resonance signal to obtain a characteristic signal, and finally a processing circuit is used to determine the temperature of the pot according to the characteristic signal. In this way, compared with the traditional way of measuring the temperature of the pot by using the heat-sensitive component, the way of measuring the temperature by using the temperature measuring circuit provided by this solution can measure the temperature of the pot in time and accurately.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings that need to be used in the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application. For those skilled in the art, other drawings can also be obtained based on these drawings without creative effort. in:

Fig. 1 is a schematic structural diagram of the first embodiment of the temperature measuring circuit provided by the present application;

2 is a schematic diagram of a resonance period, a resonance frequency and a resonance voltage amplitude of a resonance signal;

Fig. 3 is a schematic structural diagram of the second embodiment of the temperature measuring circuit provided by the present application;

Fig. 4 is a schematic diagram of the circuit structure of the third embodiment of the temperature measuring circuit provided in this embodiment;

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

Fig. 6 is a schematic structural view of an embodiment of the arrangement of the sampling coil and the heating coil of the present application;

Fig. 7 is a schematic diagram of the circuit structure of an embodiment of the arrangement of the sampling coil and the heating coil of the present application;

Fig. 8 is a schematic structural view of another embodiment of the arrangement of the sampling coil and the heating coil of the present application;

Fig. 9 is a schematic diagram of the circuit structure of another embodiment of the arrangement of the sampling coil and the heating coil of the present application;

Fig. 10 is a schematic structural block diagram of an embodiment of the cooking device of the present application;

Fig. 11 is a schematic flowchart of an embodiment of a method for measuring the temperature of a pan provided in this embodiment.

detailed description

The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. It should be understood that the specific embodiments described here are only used to explain the present application, but not to limit the present application. In addition, it should be noted that, for the convenience of description, only some structures related to the present application are shown in the drawings but not all structures. Based on the embodiments in this application, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of this 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 present application. The occurrences of this 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 understood explicitly and implicitly by those skilled in the art that the embodiments described herein can be combined with other embodiments.

Generally speaking, in the process of food cooking, it is often the case that water is added to the pot or additional ingredients are added in the middle of cooking. Or when there is a need to add water, it is necessary to add additional water. After adding cold water or ingredients, the temperature of the pot will suddenly drop. It takes a long time to reheat the pan under the fire, which takes a long time. In this embodiment, the resonance of the temperature measuring circuit is used to reflect the temperature change trend of the pan in time according to the resonance cycle width of the resonance signal or the resonance frequency or the resonance voltage amplitude change trend, which is convenient for controlling the heating of the pan according to the temperature change detection result. In order to save the heating time, the detection result is reliable and the sensitivity is high.

The temperature measurement circuit provided in this application is used to detect the temperature of the pot in the scene of heating the pot. This embodiment does not limit the heating method of the pot, for example, electromagnetic heating, electric ceramic heating or electric heating can be used. way to heat the pan.

The inventors of the present application have found through long-term research that the resonant inductance of the resonant circuit can be mutually coupled with the cooker during resonance. Therefore, when the temperature of the cooker changes, this mutual coupling relationship will change the inductance and inductance of the resonant inductor accordingly. Reflected internal resistance, and the inductance and reflected internal resistance of the resonant inductor can be determined by measuring the resonant frequency, resonant cycle width or voltage amplitude of the resonant inductor or the resonant signal. Therefore, the temperature measurement circuit provided in this embodiment can indirectly determine the temperature of the cookware according to the resonant frequency, the width of the resonant period or the voltage amplitude.

Referring to FIG. 1, FIG. 1 is a schematic structural diagram of the first embodiment of the temperature measurement circuit provided by the present application. As shown in FIG. and a processing circuit 104 .

Wherein, the DC signal is input into the resonant circuit 101 to supply power to the entire temperature measuring circuit 100 . It is the excitation circuit 102 that plays a role in controlling the on and off of the DC path of the resonant circuit 101, so as to make the resonant circuit 101 resonate and generate a resonant signal. Specifically, the resonant circuit 101 cooperates with the pot to resonate, and then generates a resonance signal that varies with the temperature of the pot.

The circuit for sampling the resonant signal is the sampling circuit 103 to obtain the characteristic signal. Based on the characteristic signal processing circuit 104 can determine the temperature of the pan.

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

Resonant frequency calculation formula:

Among them, f is the frequency, the unit is Hertz (Hz); L is the inductance, the unit is Henry (H); C is the capacitance, the unit is Farad (F).

The resonant frequency refers to that in a circuit containing capacitance and inductance, if the capacitance and inductance are connected in parallel, it may appear in a small period of time: the voltage of the capacitance gradually increases, while the current gradually decreases; the current of the inductance gradually decreases. increases, the voltage across the inductor decreases gradually. And in another small period of time: the voltage of the capacitor gradually decreases, while the current gradually increases; the current of the inductor decreases gradually, but the voltage of the inductor gradually increases. The increase of the voltage can reach a positive maximum value, and the decrease of the voltage can also reach a negative maximum value. The direction of the current will also change in the positive and negative direction during this process, which is called the electrical oscillation of the circuit. When the resonance When the sinusoidal frequency of the external input voltage of the circuit reaches a certain frequency (that is, the resonant frequency of the circuit), the inductive reactance of the resonant circuit is equal to the capacitive reactance, Z=R, and the resonant circuit is purely resistive to the outside, which is resonance. When resonance occurs, the resonant circuit amplifies the input by a factor of Q, where Q is the quality factor.

The resonant period is the reciprocal of the resonant frequency, that is, the formula for calculating the resonant period is:

The resonance voltage amplitude is the maximum absolute value of the resonance signal waveform within a resonance period.

In this embodiment, the process and principle of the resonant circuit 101 generating a resonant signal that varies with the temperature of the cookware are as follows:

When the excitation circuit 102 controls the conduction of the DC path, it supplies power to the resonant circuit 101, and the resonant inductor converts electric field energy into magnetic field energy. When the excitation circuit 102 controls the disconnection of the DC path, the resonant inductance (not shown) and the resonant capacitor (not shown) of the resonant circuit 101 resonate, and the magnetic field energy is converted into electric field energy. Coupling phenomenon, so this process can output a resonance signal reflecting the temperature change of the pot.

The temperature measurement circuit 100 provided in this embodiment provides a DC signal for the resonant circuit 101 to supply power, and controls the on and off of the DC path of the resonant circuit 101 through the excitation circuit 102, so that the resonant circuit 101 resonates and outputs a resonant signal. The resonant signal carries the temperature change information of the pot, and then the sampling circuit 103 is used to sample the resonant signal to obtain a characteristic signal, and finally the processing circuit 104 is used to determine the temperature of the pot based on the characteristic signal. In this way, compared with the traditional way of measuring the temperature of the pan by using the heat-sensitive component, the way of measuring the temperature by using the temperature measuring circuit 100 provided by this solution can timely and accurately measure the temperature of the pan.

In a specific embodiment, the sampling circuit 103 includes a first resistor (not shown), the excitation circuit 102 is connected to the first end of the first resistor, and the processing circuit 104 is connected to the second end of the first resistor for collecting the resonance voltage amplitude value. In fact, the first resistor is connected in series with the resonant circuit 101 to divide the voltage. Since the change of the voltage across the first resistor is the same as the change of the resonant voltage, the first resistor can be used to collect the amplitude of the resonant voltage.

In another specific embodiment, the sampling circuit 103 further includes a sampling coil (not shown in the figure), and the resonant circuit 101 is arranged corresponding to the sampling coil for sampling the resonant cycle width or resonant frequency.

Optionally, the processing circuit 104 may be a CPU (Central Processing Unit, central processing unit), and the processing circuit 104 may be an integrated circuit chip having a signal processing capability. Processing circuit 104 may also be a general purpose processor, digital signal processor (DSP), application specific integrated circuit (ASIC), off-the-shelf programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic device, discrete hardware component . A general-purpose processor may be a microprocessor, or the processor may be any conventional processor, or the like.

In a specific embodiment, the manufacturer obtains the corresponding relationship table between the temperature of the pan and the change of the resonant frequency, or the table of the corresponding relationship between the temperature of the pan and the change of the resonance period width, or the change of the temperature of the pan and the amplitude of the resonance voltage through multiple tests. The corresponding relationship table. Furthermore, in the actual heating process, the temperature of the cooker is obtained according to the above correspondence table and the change in the width of the resonant period, the change in the amplitude of the resonant voltage, or the change in the resonant frequency obtained when the temperature measuring circuit resonates.

Referring to FIG. 3, FIG. 3 is a schematic structural diagram of the second embodiment of the temperature measurement circuit provided by the present application. As shown in FIG. The processing circuit 104 and the control circuit 105 .

Wherein, the exciting circuit 102 is respectively connected to the resonant circuit 101 , the control circuit 105 and the sampling circuit 103 , and the sampling circuit 103 is connected to the processing circuit 104 .

Wherein, a DC signal is input to the resonant circuit 101 for power supply. The excitation 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 pan. Specifically, the resonant circuit 101 cooperates with the pot to resonate, and then generates a resonance signal that varies with the temperature of the pot.

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

The control circuit 105 is used to output a periodic PPG (Programme Pulse Generator, Programmable Pulse Program Generator) control signal to control the on/off of the excitation circuit 102 .

The temperature measuring circuit 100 provided in this embodiment inputs a DC signal to supply power to the resonant circuit 101, and uses the control circuit 105 to output a periodic PPG control signal to control the turn-off and conduction of the excitation circuit 102, thereby controlling the DC path of the resonant circuit 101 Turn off and on, so that the resonant circuit 101 generates a resonant signal, and then use the sampling circuit 103 to collect the resonant signal to obtain the characteristic signal, and finally use the processing circuit 104 to determine the temperature change of the pot according to the characteristic signal. In this way, compared with the traditional way of measuring the temperature of the pan by using the heat-sensitive component, the way of measuring the temperature by using the temperature measuring circuit 100 provided by this solution can timely and accurately measure the temperature of the pan.

Referring to FIG. 4, FIG. 4 is a schematic diagram of the circuit structure of the third embodiment of the temperature measuring circuit provided in this embodiment. As shown in FIG. 4, in the temperature measuring circuit 100 provided in this embodiment, the resonant circuit 101 includes a resonant capacitor C1 and The resonant coil L1 connected in parallel with the resonant capacitor C1 inputs a direct current signal DC to one end of the resonant coil L1 for power supply. The pan is placed above the resonant coil L1, so that the resonant circuit 101 is mutually coupled with the pan when resonance occurs, and generates a resonant signal that varies with the temperature of the pan. The pan and the resonant coil L1 are inductively coupled, and the resonant coil L1 and the resonant capacitor C1 resonate. When the temperature of the pan changes, the coupling inductance changes, thereby affecting the resonance period width of the resonance signal or the resonance voltage amplitude or resonance frequency.

Optionally, the temperature measurement circuit 100 includes a second diode D2, wherein the AC signal AC is input to the anode of the second diode D2, and the resonant circuit 101 is connected to the cathode of the second diode D2 for the AC signal The AC is rectified to provide the required direct current signal DC for the resonant circuit 101 . It can be understood that, according to actual application scenarios, any other feasible rectification circuit may be used to rectify the AC signal AC, which is not specifically limited herein.

The excitation circuit 102 includes a first power transistor Q1, and inputs the first pulse modulation signal PWM1 to the gate G of the first power transistor Q1, the other end of the resonant coil L1 and the sampling circuit 103 are connected to the source C of the first power transistor Q1, and the second A drain E of the power transistor Q1 is grounded. Wherein, the first power transistor Q1 is configured to be turned off or turned on according to the first pulse modulation signal PWM1 , so as to turn on or turn off the DC path of the resonant circuit 101 .

Optionally, 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 the first end of the first resistor R1, the processing circuit 104 is connected to the second end of the first resistor R1, and the first resistor R1 is used It is used to collect the resonance voltage amplitude. Optionally, the sampling circuit 103 may further include a first diode D1, a second resistor R2 and a first capacitor C2, the first end of the first resistor R1 is connected to the source of the first power transistor Q1 through the first diode D1 Pole C.

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, and the second end of the first resistor R1 is connected to the first The first terminal of the second resistor R2 and the second terminal of the second resistor R2 are 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.

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

Since the first resistor R1 and the second resistor R2 are connected in series with the resonant circuit 101, when the resonant circuit 101 resonates to generate a resonant voltage signal, the first resistor R1 and the second resistor R2 can divide the voltage, that is, the second The change of the voltage across the first resistor R1 and the second resistor R2 is synchronized with the voltage change of the resonant voltage signal, so the collected change of the voltage amplitude across the first resistor R1 or the second resistor R2 can reflect the resonant voltage of the resonant voltage signal change in magnitude.

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

This embodiment provides a temperature measurement circuit 100 based on a single-tube resonant circuit design. Only one power tube is needed to resonate the resonant circuit 101 and output a resonant signal, thereby making the control circuit for controlling the temperature measurement circuit 100 simpler and saving materials. and reduce costs.

Referring to FIG. 5 , FIG. 5 is a schematic diagram of the circuit structure of the fourth embodiment of the temperature measuring circuit provided in this embodiment. As shown in FIG. 5 , the resonant circuit 101 includes a resonant capacitor C1 and a resonant coil L1 connected in series with the resonant capacitor C1 . A pan is placed above the resonant coil L1, so that the resonant circuit 101 is mutually coupled with the pan when resonance occurs, and generates a resonance signal that changes with the temperature of the pan.

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

Wherein, the second pulse modulation signal PWM2 is input to the gate G of the second power transistor Q2, and the direct current signal DC is input to the source C of the second power transistor Q2. The grid G of the third power transistor Q3 inputs the third pulse modulation signal PWM3, the source C of the third power transistor Q3 is respectively connected to the drain E of the second power transistor Q2 and one end of the resonant coil L1, and the third power transistor Q3 The drain of E is grounded.

Among them, the third power transistor Q3 and the second power transistor Q2 are respectively under the control of the third pulse modulation signal PWM3 and the second pulse modulation signal PWM2, and output the direct current signal DC that meets the requirements to the resonant circuit 101, so that the resonant circuit 101 generates Resonate and generate a resonance signal, which carries the temperature change of the pan.

In this embodiment, the phases of the second pulse modulation signal PWM2 and the third pulse modulation signal PWM3 are inverted. That is, when the second pulse modulation signal PWM2 is at a low level, the third pulse modulation signal PWM3 is at a high level; otherwise, when the second pulse modulation signal PWM2 is at a high level, the third pulse modulation signal PWM3 is at a high level. Signal PWM3 is low level. This way can ensure that the third power transistor Q3 and the second power transistor Q2 cannot be turned on at the same time, so as to avoid the current pass-through caused by the simultaneous turn-on.

Wherein, the third power transistor Q3 and the second power transistor Q2 may be IGBT field effect transistors with damping diodes.

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

Optionally, the temperature measurement circuit 100 includes a second diode D2, wherein an AC signal AC is input to the positive pole of the second diode D2, and the excitation circuit 102 is connected to the negative pole of the second diode D2 for controlling the AC signal. The AC is rectified to input the required direct current signal DC to the excitation circuit 102 . It can be understood that, according to actual application scenarios, any other feasible rectification circuit may be used to rectify the AC signal AC, which is not specifically limited herein.

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

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

This embodiment provides a temperature measurement circuit 100 based on a half-bridge resonant circuit design, so that the temperature measurement circuit 100 has good temperature measurement performance and high temperature measurement efficiency.

Optionally, in the temperature measuring circuit 100 provided in the above two embodiments, the sampling circuit 103 may further include a sampling coil L2, and the resonant coil L1 is set corresponding to the sampling coil L2 for collecting the resonant cycle width or resonant frequency. Specifically, the sampling coil L2 and the resonant coil L1 are mutually coupled, and then the resonant cycle width or resonant frequency is collected.

In a specific application scenario, please refer to FIG. 6 and FIG. 7 in combination. FIG. 6 is a schematic structural diagram of an embodiment of the arrangement of the sampling coil and the resonant coil of the present application, and FIG. 7 is an embodiment of the arrangement of the sampling coil and the resonant coil of the present application. The schematic diagram of the circuit structure. The sampling coil L2 of this embodiment is arranged at the center of the resonant coil L1 to collect the resonant signal.

Please refer to FIG. 8 and FIG. 9 in conjunction. FIG. 8 is a schematic structural diagram of another embodiment of the arrangement of the sampling coil and the resonant coil of the present application, and FIG. 9 is a schematic circuit structure diagram of another embodiment of the arrangement of the sampling coil and the resonant coil of the present application. The sampling coil L2 of this embodiment is a current transformer, and the sampling coil L2 is sheathed on the lead-out line of the resonant coil L1 to collect the resonant signal.

In addition to the above two arrangement manners, the arrangement manner of the sampling coil L2 relative to the resonant coil L1 may also have other manners, which are not limited here.

Please refer to FIG. 10 . FIG. 10 is a schematic structural block diagram of an embodiment of the cooking device of the present application. As shown in FIG. 10 , the cooking device 110 of this 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, which may be an induction cooker, an IH rice cooker, etc. It does not need an open flame or conduction heating and allows heat to be directly generated at the bottom of the pot, so the thermal efficiency is greatly improved. An induction cooker is an electric cooking appliance made using the principle of electromagnetic induction heating. It is composed of high-frequency induction heating coil, high-frequency power conversion device, controller and ferromagnetic material pot bottom cooker and other parts.

The induction cooker mainly consists of two parts: one is the electronic circuit system capable of generating high-frequency alternating magnetic field (including the coil plate of the induction cooker, that is, the above-mentioned heating coil); the other is the structural shell used to fix the electronic circuit system and carry the pot (including furnace panels that can withstand high temperatures and rapid changes in cold and heat).

Referring to Fig. 11, Fig. 11 is a schematic flow chart of an embodiment of the method for measuring the temperature of the pan provided in this embodiment. As shown in Fig. 11, the method for measuring the temperature of the pan provided in this embodiment uses The temperature circuit is implemented, wherein, when measuring temperature, a DC signal is provided for the temperature measuring circuit. Specifically, the pot temperature measurement method may include the following steps:

S201: Input a pulse modulation signal to the temperature measuring circuit to excite the temperature measuring circuit to resonate and output a resonant signal that varies with the temperature of the pan.

In this embodiment, if the temperature measuring circuit is the temperature measuring circuit provided in the third embodiment, the temperature measuring circuit uses single tube resonance to generate a resonance signal. That is to say, the temperature measuring circuit includes a power tube. Therefore, in this case, the control circuit directly provides a pulse modulation signal to the power tube to make the temperature measuring circuit work, and then cooperate with the cooker to output a resonance signal.

If the temperature measurement circuit is the temperature measurement circuit provided by the fourth embodiment, the temperature measurement circuit uses half-bridge resonance to generate a resonance signal. That is to say, the temperature measurement circuit includes at least two power tubes. Therefore, in this case, the control circuit needs to provide at least two pulse modulation signals for the temperature measurement circuit to respectively drive the two power tubes to work, and then cooperate with the cooker. output resonance signal. Among them, the phases of the two pulse modulation signals are inverted.

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

As for the specific characteristics of the provided pulse modulation signal, such as duty cycle, cycle or frequency, etc., can be set according to specific application scenarios, and are not specifically limited here.

S202: Obtain a characteristic signal of the resonance signal.

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

S203: Determine the temperature of the pot according to the characteristic signal.

In this embodiment, the manufacturer obtains the corresponding relationship table between the temperature of the pan and the change of the resonant frequency, or the table of the corresponding relationship between the temperature of the pan and the change of the width of the resonance period, or the relationship between the temperature of the pan and the change of the resonance voltage amplitude through multiple tests. Correspondence table. Furthermore, in the actual heating process, the temperature of the cooker is obtained according to the above correspondence table and the change in the width of the resonant period, the change in the amplitude of the resonant voltage, or the change in the resonant frequency obtained when the temperature measuring circuit resonates.

The method for measuring the temperature of the pan provided in this embodiment includes inputting a pulse modulation signal to the temperature measuring circuit to stimulate the temperature measuring circuit to resonate and output a resonance signal that changes with the temperature of the pan, obtain the characteristic signal of the resonance signal, and determine the temperature of the pan based on the characteristic signal. the temperature of the tool. In this way, the temperature of the pan can be determined quickly, precisely and efficiently.

To sum up, the temperature measuring circuit provided by this application inputs a DC signal to supply power to the resonant circuit, and controls the shut-off and conduction of the DC path of the resonant circuit through the excitation circuit, so that the resonant circuit generates a resonant signal with information about the temperature change of the pot , and then use the sampling circuit to collect the resonance signal to obtain the characteristic signal, and finally use the processing circuit to determine the temperature of the pot based on the characteristic signal. In this way, compared with the traditional way of measuring the temperature of the pot by using the heat-sensitive component, the way of measuring the temperature by using the temperature measuring circuit provided by this solution can measure the temperature of the pot in time and accurately.

The above is only the implementation of the application, and does not limit the patent scope of the application. Any equivalent structure or equivalent process conversion made by using the specification and drawings of the application, or directly or indirectly used in other related technologies fields, are all included in the scope of patent protection of this application in the same way.

In the several implementation manners provided in this application, it should be understood that the disclosed methods and devices may be implemented in other ways. For example, the device implementation described above is only illustrative. For example, the division of the above-mentioned modules or units is only a logical function division. In actual implementation, there may be other division methods. Or it can be integrated into another system, or some features can be ignored, or not implemented.

Claims (11)

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.

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