Dry burning detection method based on active microwave detection and intelligent electric appliance

Abstract

The invention provides a dry burning detection method based on active microwave detection and an intelligent electric appliance. The method comprises the following steps: transmitting a microwave signal to the cookware, and receiving a reflection signal of the microwave signal; obtaining a phase angle of the reflected signal, and extracting characteristic parameters of the phase angle; and judging whether the cookware is dry-heated according to the characteristic parameters. The technical problem that dry burning detection lags behind in the prior art is solved, and early warning is triggered before moisture is completely evaporated.

Description

Dry-burning detection method and smart appliances based on active microwave detection Technical Field

[0001] This application relates to the field of smart electrical appliance technology, and in particular to a dry-burning detection method based on active microwave detection and a smart electrical appliance. Background Technology

[0002] As people's living standards improve and technologies such as the internet, big data, artificial intelligence, and voice interaction become more widespread, traditional lifestyles are gradually changing, and the use of home appliances is increasingly moving towards intelligentization. While bringing more convenience to users, the functions of various home appliances are also becoming more diversified.

[0003] Range hoods are essential appliances for people to remove cooking fumes during daily cooking. However, during cooking, users may become distracted and cause cookware to dry-burn, producing a large amount of fumes and even posing a fire hazard. Currently, range hoods cannot actively detect dry-burning conditions, and existing technologies to prevent dry-burning mostly rely on temperature sensors or smoke detectors, which have a delayed response and cannot predict the risk of dry-burning in advance. Summary of the Invention

[0004] Therefore, it is necessary to provide a dry-burning detection method and a smart appliance based on active microwave detection to address the above-mentioned technical problems.

[0005] In a first aspect, embodiments of the present invention propose a dry-burning detection method based on active microwave detection, the method comprising:

[0006] It emits microwave signals to the cookware and receives the reflected signals.

[0007] Obtain the phase angle of the reflected signal and extract the characteristic parameters of the phase angle;

[0008] The pot is determined to be dry-burned based on the characteristic parameters.

[0009] In some embodiments, a single-frequency microwave signal is emitted to the cookware, the characteristic parameter including the dielectric loss tangent.

[0010] In some embodiments, determining whether the cookware is dry-burning based on the characteristic parameters includes:

[0011] Obtain the slope abrupt change factor of the dielectric loss tangent;

[0012] Based on the slope mutation factor, it is determined whether the cookware is dry-burning.

[0013] In some embodiments, dual-frequency microwave signals are emitted to the cookware, and the characteristic parameters include the ratio of the phase angles corresponding to the dual-frequency microwave signals.

[0014] In some embodiments, determining whether the cookware is dry-burning based on the characteristic parameters includes:

[0015] Obtain the rate of change of the ratio of the phase angles over time;

[0016] Based on the rate of change, determine whether the cookware is dry-burning.

[0017] In some embodiments, the method further includes:

[0018] Establish a coupling model between the phase angle and the liquid level height;

[0019] The liquid level in the pot is determined based on the phase angle and the coupling model.

[0020] In some embodiments, the method further includes:

[0021] The current cooking mode of the cookware is determined based on the temporal fluctuation characteristics of the dielectric loss tangent.

[0022] In some embodiments, the method further includes:

[0023] The current cooking mode of the cookware is determined based on the temporal fluctuation characteristics of the dielectric loss tangent.

[0024] In some embodiments, the method further includes:

[0025] The material of the cookware is determined based on the difference in the phase angles.

[0026] Match the corresponding cooking mode according to the material.

[0027] Secondly, embodiments of the present invention propose a smart appliance that employs the detection method described in the first aspect, wherein the smart appliance is one of a range hood or an integrated stove.

[0028] In some embodiments, the method includes:

[0029] It emits microwave signals to the cookware and receives the reflected signals.

[0030] Obtain the phase angle of the reflected signal and extract the characteristic parameters of the phase angle;

[0031] The pot is determined to be dry-burned based on the characteristic parameters.

[0032] In some embodiments, a single-frequency microwave signal is emitted to the cookware, the characteristic parameter including the dielectric loss tangent.

[0033] In some embodiments, determining whether the cookware is dry-burning based on the characteristic parameters includes:

[0034] Obtain the slope abrupt change factor of the dielectric loss tangent;

[0035] Based on the slope mutation factor, it is determined whether the cookware is dry-burning.

[0036] In some embodiments, dual-frequency microwave signals are emitted to the cookware, and the characteristic parameters include the ratio of the phase angles corresponding to the dual-frequency microwave signals.

[0037] In some embodiments, determining whether the cookware is dry-burning based on the characteristic parameters includes:

[0038] Obtain the rate of change of the ratio of the phase angles over time;

[0039] Based on the rate of change, determine whether the cookware is dry-burning.

[0040] In some embodiments, the method further includes:

[0041] Establish a coupling model between the phase angle and the liquid level height;

[0042] The liquid level in the pot is determined based on the phase angle and the coupling model.

[0043] In some embodiments, the method further includes:

[0044] The current cooking mode of the cookware is determined based on the temporal fluctuation characteristics of the dielectric loss tangent.

[0045] In some embodiments, the method further includes:

[0046] The current cooking mode of the cookware is determined based on the temporal fluctuation characteristics of the dielectric loss tangent.

[0047] In some embodiments, the method further includes:

[0048] The material of the cookware is determined based on the difference in the phase angles.

[0049] Match the corresponding cooking mode according to the material.

[0050] Compared with existing technologies, this technical solution has the following advantages: it transmits microwave signals to the cookware and receives the reflected signals, obtains the phase angle of the reflected signals, extracts the characteristic parameters of the phase angle, and determines whether the cookware is dry-burning based on the characteristic parameters, thus solving the technical problem of lagging dry-burning detection in existing technologies. Attached Figure Description

[0051] Figure 1 is a schematic diagram of the module connection of a smart appliance according to an embodiment of the present invention;

[0052] Figure 2 is a flowchart of a dry burning detection method based on active microwave detection according to an embodiment of the present invention;

[0053] Figure 3 is a flowchart of a liquid level determination method according to an embodiment of the present invention;

[0054] Figure 4 is a flowchart of a cooking mode determination method according to an embodiment of the present invention. Detailed Implementation

[0055] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are merely some examples or embodiments of the present invention. For those skilled in the art, the present invention can be applied to other similar scenarios based on these drawings without creative effort. Unless obvious from the context or otherwise specified, the same reference numerals in the drawings represent the same structures or operations.

[0056] As indicated in this invention and the claims, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" do not specifically refer to the singular and may also include the plural. Generally speaking, the terms "comprising" and "including" only indicate the inclusion of explicitly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements.

[0057] While this invention makes various references to certain modules in an apparatus according to embodiments of the invention, any number of different modules can be used and run on a computing device and / or processor. Modules are merely illustrative, and different aspects of the apparatus and methods may use different modules.

[0058] It should be understood that when a unit or module is described as "connected" or "coupled" to other units, modules, or blocks, it may refer to a direct connection or coupling, or communication with other units, modules, or blocks, or the presence of intermediate units, modules, or blocks, unless the context explicitly indicates otherwise. The term "and / or" as used herein may include any and all combinations of one or more of the related listed items.

[0059] Figure 1 is a schematic diagram of the module connection of a smart appliance according to an embodiment of the present invention. As shown in Figure 1, the smart appliance includes a main controller and a microwave transceiver module and a fan drive module connected to the main controller.

[0060] Smart appliances include range hoods and integrated cooktops.

[0061] Microwave transceiver modules are installed, for example, under a smoke hood or smoke baffle, to transmit microwave signals to the cookware and receive its reflected signals.

[0062] The main controller executes the dry burning detection method and controls the fan using the fan drive module based on the dry burning judgment result.

[0063] Figure 2 is a flowchart of the dry-burning detection method based on active microwave detection according to an embodiment of the present invention. As shown in Figure 1, the process includes the following steps:

[0064] S202: Transmit microwave signals to the cookware and receive its reflected signals;

[0065] S204: Obtain the phase angle of the reflected signal and extract the characteristic parameters of the phase angle;

[0066] S206: Determine whether the cookware is dry-burning based on the characteristic parameters.

[0067] Based on the above steps S202-S206, a microwave signal is emitted to the cookware and its reflected signal is received. The phase angle of the reflected signal is obtained and the characteristic parameters of the phase angle are extracted. Based on the characteristic parameters, it is determined whether the cookware is dry-burning, which solves the technical problem of lagging dry-burning detection in the prior art and triggers an early warning before the moisture evaporates completely.

[0068] In the first example embodiment, the microwave signal is a single-frequency signal, such as 20 GHz. Water molecules are highly polar, resulting in a phase angle close to 180° (total internal reflection), while air has approximately 0° (no phase shift). When the medium state inside the pot changes abruptly (water → air), the disappearance of the inflection point of the dielectric loss tangent (tanδ) is captured, enabling an early warning of the risk of dry burning before the temperature rises significantly.

[0069] When a microwave signal is incident on a cookware, the reflection coefficient for:

[0070]

[0071] Where the complex dielectric constant is (Plural form).

[0072] In this example embodiment, the dry-burning detection method is specifically as follows:

[0073] Step 1: Transmit microwave signals (For example, transmitting a 20GHz sine wave):

[0074]

[0075] Where A represents the amplitude of the microwave signal, and t represents time. Indicates frequency.

[0076] Step 2: Receive the reflected signal :

[0077] Where B represents the amplitude of the reflected signal, This represents the phase angle of the reflected signal.

[0078] Step 3: I-channel demodulation:

[0079] Low-pass filtering removes high-frequency components ( )back:

[0080] Step 4: Q-path demodulation:

[0081] Low-pass filtering removes high-frequency components ( )back:

[0082] IQ demodulation is a common signal processing technique widely used in communications, radio, and other fields. In IQ demodulation, I represents the real part and Q represents the imaginary part. This demodulation scheme can decompose complex signals into simple orthogonal components, which facilitates signal processing and analysis. The phase angle can also be obtained directly using IQ demodulation chips or circuits.

[0083] Step 5: Phase Angle calculate:

[0084] This arctangent function uses The function is chosen because it returns the phase angle across all quadrants, making it valid for all angles. Therefore, it can be used to convert vectors to angles without the risk of division by zero, and it also returns results in the correct quadrant. In contrast, the ordinary arctangent function arctan(x) only outputs values ​​in the quadrant. It cannot cover the complete 360° phase change, when This can cause a phase jump (e.g., θ=135° is incorrectly mapped to -45°).

[0085] Step 6: Dielectric loss tangent calculate:

[0086]

[0087] When dry burning, This causes the molecule to approach 0, resulting in a lower dielectric loss tangent. The curve loses its abrupt inflection point.

[0088] Step 7: Determining if the product is dry-burned:

[0089] Define the slope mutation factor (the second derivative characterizes the curve mutation).

[0090] Through slope mutation factor The nonlinear abrupt changes in the dielectric relaxation process are quantified. For example, during normal cooking, K fluctuates periodically (relaxation is caused by moisture evaporation); during dry burning, the absolute value of K drops sharply (the medium suddenly becomes air, and relaxation disappears).

[0091] The dry-burning test grading is shown in Table 1 below:

[0092] Table 1

[0093]

[0094] For example, when 0.5 ≥ K ≥ 0.15 and lasts for 2 seconds, the corresponding response level is L1, at which time the voice prompt "Please pay attention to the water level in the pot" is given; when 0.15 > K ≥ 0.08 and lasts for 3 seconds, the corresponding response level is L2, at which time the stove firepower is reduced by 50%, and the range hood fan speed is increased by 1 level; when 0.08 > K, the corresponding response level is L3, at which time the gas valve is closed, the range hood fan speed is increased to the highest level, and an alarm is issued.

[0095] In this example embodiment, in addition to dry burning detection, it also links with equipment such as range hoods to achieve active protection under different dry burning levels.

[0096] During cooking, the liquid level in the pot can be measured for further control over the cooking process. Current technology uses ultrasonic level gauges to detect liquid level, but these gauges are susceptible to interference from cooking fumes and are prone to failure, and also require additional costs.

[0097] In a further embodiment, as shown in FIG3, the method further includes:

[0098] S302: Establish the coupling model between the phase angle and the liquid level height:

[0099] There is a nonlinear positive correlation between the phase angle and the liquid level height. Based on this relationship, a coupling model between the two is established.

[0100] S304: Determine the liquid level height based on the phase angle and the coupling model.

[0101] After obtaining the phase angle using the above method, it can be substituted into the coupling model to solve for the liquid level height.

[0102] In practical applications, when the liquid level H is less than the threshold Ha, a voice prompt will remind you to add water; when the liquid level H is greater than the threshold Hb, a voice prompt will remind you that there is too much water to prevent overflow.

[0103] In this embodiment, the liquid level can be obtained without additional hardware, reducing costs.

[0104] For existing smart appliances, such as range hoods, users need to adjust the fan speed manually according to the cooking mode, resulting in a low level of automation.

[0105] In a further embodiment, the method further includes: determining the current cooking mode of the cookware based on the temporal fluctuation characteristics of the dielectric loss tangent.

[0106] When the dielectric loss tangent tanδ rises slowly (e.g., slope 0.02 / s), it is determined to be frying mode, and the fan speed is switched to medium. When the dielectric loss tangent tanδ oscillates violently (amplitude > 0.15), it is determined to be stewing mode. When the liquid level is less than the threshold Ha, a voice prompt will remind you to add water and the fan speed will be switched to low. When the dielectric loss tangent tanδ changes rapidly at high frequency, it is determined to be stir-frying mode, and the fan speed will be switched to high.

[0107] In this embodiment, the current cooking mode of the cookware is automatically determined based on the temporal fluctuation characteristics of the dielectric loss tangent, thereby improving the level of intelligence and realizing intelligent control.

[0108] Since single-frequency microwave signals are susceptible to steam interference, in the second example embodiment, the microwave signal is a dual-frequency microwave signal, for example, alternately transmitting 20GHz and 1GHz dual-frequency microwave signals to the cookware to cancel out environmental noise.

[0109] In this example embodiment, the dry-burning detection method is specifically as follows:

[0110] Step 1: Transmit a 20GHz sine wave signal:

[0111]

[0112] in, Indicates frequency.

[0113] Step 2: Receive the reflected signal:

[0114] Step 3: Obtain the first phase angle through IQ demodulation

[0115]

[0116]

[0117] =arctan2( )

[0118] Step 4: Similarly, obtain the second phase angle corresponding to the 1GHz microwave signal.

[0119] Step 5: Define the dual-frequency phase difference ratio R:

[0120]

[0121] During normal cooking, the R value changes monotonically with temperature (dominated by water molecule relaxation); when dry burning occurs, the R value changes abruptly (no relaxation peak in the air dielectric response).

[0122] Step 6: Dry burning test:

[0123] For example, when If the condition persists for 3 seconds or other threshold values, it is considered dry burning. (Laboratory calibration value) It represents the rate of change of the ratio of phase angles over time.

[0124] Considering that induction cookers or cooking modes are often related to the material of the cookware, it is generally necessary to manually select the cookware material.

[0125] In a further embodiment, as shown in FIG4, the method further includes:

[0126] S402: Determine the material of the cookware based on the difference in the phase angles;

[0127] S404: Match the corresponding cooking mode according to the material.

[0128] The material of the cookware affects the phase angle of its reflected signal. Therefore, in this embodiment, the material of the cookware can be determined based on the difference in phase angle Δθ, as shown in Table 2.

[0129] Table 2

[0130]

[0131] After determining the material of the cookware, the system executes the corresponding cooking mode. For example, when a ceramic pot is identified, the system automatically limits the maximum power to prevent it from cracking.

[0132] It should be understood that although the steps in the flowchart above are shown sequentially as indicated by the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowchart above may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages in other steps.

[0133] This invention also proposes a smart appliance that uses the detection method described in the above embodiments. The smart appliance is one of a range hood or an integrated stove.

[0134] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, or optical storage, etc. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.

[0135] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0136] The above embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A dry-burning detection method based on active microwave detection, characterized in that, The method includes: transmitting a microwave signal to a cookware and receiving its reflected signal; obtaining the phase angle of the reflected signal and extracting the characteristic parameters of the phase angle; and determining whether the cookware is dry-burning based on the characteristic parameters.

2. The method according to claim 1, characterized in that, A single-frequency microwave signal is emitted to the cookware, the characteristic parameter of which includes the dielectric loss tangent.

3. The method according to claim 2, characterized in that, The step of determining whether the cookware is dry-burning based on the characteristic parameters includes: obtaining the slope abrupt change factor of the dielectric loss tangent; and determining whether the cookware is dry-burning based on the slope abrupt change factor.

4. The method according to claim 1, characterized in that, The cookware is emitting dual-frequency microwave signals, and the characteristic parameters include the ratio of the phase angles corresponding to the dual-frequency microwave signals.

5. The method according to claim 4, characterized in that, The step of determining whether the cookware is dry-burning based on the characteristic parameters includes: obtaining the rate of change of the ratio of the phase angles over time; and determining whether the cookware is dry-burning based on the rate of change.

6. The method according to claim 1, characterized in that, The method further includes: establishing a coupling model between the phase angle and the liquid level; and determining the liquid level inside the pot based on the phase angle and the coupling model.

7. The method according to claim 2, characterized in that, The method further includes: determining the current cooking mode of the cookware based on the temporal fluctuation characteristics of the dielectric loss tangent.

8. The method according to claim 3, characterized in that, The method further includes: determining the current cooking mode of the cookware based on the temporal fluctuation characteristics of the dielectric loss tangent.

9. The method according to claim 4, characterized in that, The method further includes: determining the material of the cookware based on the difference in phase angles; and matching the corresponding cooking mode based on the material.

10. A smart appliance, characterized in that, It employs the detection method described in any one of claims 1 to 9, wherein the intelligent appliance is one of a range hood or an integrated stove.

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