A cooking apparatus

Abstract

The utility model relates to a kind of cooking equipment, including shell, processing module is built-in in shell, heating device and electric capacity sensor, electric capacity sensor includes at least two perception electrodes, each perception electrode is distributed in heating device periphery and extends to center across heating device outer circle;Cooking equipment is provided with capacitance digital conversion circuit, capacitance digital conversion circuit is respectively coupled each perception electrode, to obtain the self-capacitance of perception electrode and / or mutual capacitance formed by two perception electrodes;Processing module is coupled capacitance digital conversion circuit, for the detection signal of whether there is utensil on cooking equipment according to self-capacitance and / or mutual capacitance output.

Description

Technical Field

[0001] This utility model relates to household stoves, and more particularly to a cooking device. Background Technology

[0002] Ceramic cooktops utilize resistance heating, cooking food through a combination of infrared radiation and conduction. Compared to induction cooktops, ceramic cooktops do not rely on magnetic field induction, making them suitable for any cookware, including glass, ceramic, and stainless steel.

[0003] For safety, energy efficiency, and equipment protection reasons, such as preventing the heating panel from cracking due to high temperatures from dry heating and avoiding the risk of burns, electric ceramic cooktops need to detect whether a pot is placed on top. Traditional sensing solutions include weight, infrared, electromagnetic, and current feedback. Current sensing is a post-event feedback; weight sensing is affected by the elastic support required by the panel itself, requiring a probe to extend out of the panel and touch the bottom of the pot, resulting in a complex design; infrared sensing is difficult to detect glass or slanted-bottom pots, and electromagnetic sensing is difficult to detect metal pots.

[0004] Patent CN119914906A provides a cooking appliance and a method for detecting the absence of a pot. The method detects the pot based on capacitance. It uses a double-layer induction plate set on the side of the main body of the stove plate near the panel. The double-layer induction plate and the resistor form an RC oscillation. When the pot is placed on it, the capacitance changes, causing the oscillation to change. Based on this, the detection is not limited to the placement of metal pots. However, because the capacitance is concentrated between the two plates, the capacitance change is small, resulting in low detection sensitivity and difficulty in detecting small pots with a bottom of less than 10cm. Utility Model Content

[0005] To address the shortcomings of existing technologies, this utility model provides a cooking device.

[0006] The cooking device of this utility model includes a housing, within which a processing module, a heating device, and a capacitive sensor are built. The capacitive sensor includes at least two sensing electrodes, each distributed around the heating device and extending from the outer edge of the heating device toward the center. The cooking device is equipped with a capacitance-to-digital conversion circuit, which is coupled to each sensing electrode to obtain the self-capacitance of the sensing electrode and / or the mutual capacitance formed by pairs of sensing electrodes. The processing module is coupled to the capacitance-to-digital conversion circuit and is used to output a detection signal indicating whether a pot or pan is present on the cooking device based on the self-capacitance and / or mutual capacitance.

[0007] Furthermore, the sensing electrodes are configured to be at least three.

[0008] Furthermore, the sensing electrodes are evenly distributed around the heating device.

[0009] Furthermore, the sensing electrode extends inward from the outer ring of the heating device by at least 1 / 6 of the radius of the heating device.

[0010] Furthermore, the cooking device is an electric ceramic stove with a heating panel on the top surface of the shell. Several springs are located at the bottom of the heating panel, and each spring is distributed around the heating device to elastically support the heating panel. The springs are also used as sensing electrodes.

[0011] Furthermore, the spring is made of a high-temperature resistant and conductive material.

[0012] Furthermore, it includes a capacitor for filtering out AC mains frequencies, with the spring coupled to the processing module via the capacitor.

[0013] Furthermore, the spring is provided with a conductor for enhancing the capacitance signal, and the conductor is coupled to the spring.

[0014] Furthermore, the conductor can be integrally formed with the spring as an extension of the spring; or the conductor and the spring can be separate components.

[0015] Furthermore, the capacitor-to-digital converter circuit couples each sensing electrode separately through a switch array.

[0016] Furthermore, it includes a prompting device for the coupling processing module.

[0017] The cooking device of this invention achieves a simple structure and high sensitivity by means of the electrode arrangement of the capacitive sensor, while significantly improving the detection limit of the pot diameter. Attached Figure Description

[0018] Figure 1 A schematic diagram of the structure of a reusable electric ceramic stove with springs around the stove as sensing electrodes is given.

[0019] Figure 2 A circuit diagram showing a spring connected in series with a small capacitor to the chip is provided.

[0020] Figure 3 A circuit diagram is shown that connects the CDC and electrodes in the chip via a switch array. Detailed Implementation

[0021] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention.

[0022] See Figures 1 to 3The housing of cooking appliances such as electric ceramic cooktops consists of a base and a heating panel. A heating element 5 and a control circuit board are housed within the housing. The heating element 5 includes, but is not limited to, resistance heating or infrared heating. The control circuit board contains a chip 1, which integrates a processing module and a capacitance-to-digital converter (CDC). The capacitance-to-digital converter (CDC), such as AD7142 or AD7147, uses Δ-Σ modulation to directly convert the measured capacitance value into a digital value by repeatedly charging and discharging the capacitor under test and comparing it with a reference capacitance (see US Patent Number: 5,134,401). This improves the measurement sensitivity of capacitance to the 1ff level and provides multiple channels, simplifying circuit design and effectively reducing costs and installation difficulty.

[0023] Several sensing electrodes 4 are arranged around the heating device 5. The sensing electrodes 4 are distributed around the heating device 5, extending from the outer ring of the heating device 5 towards the center. The extension direction can be inclined or towards the center. To further improve the detection effect, the length of the electrode extension from the outer ring of the heating device 5 inward is at least 1 / 6 of the radius of the heating device 5. There are at least two sensing electrodes 4. A capacitance-to-digital conversion circuit is coupled to each sensing electrode 4 via wire 2 to obtain the self-capacitance of the sensing electrode 4 and / or the mutual capacitance formed by pairs of sensing electrodes 4. The processing module is coupled to the capacitance-to-digital conversion circuit via wire 2 to output a detection signal indicating the presence or absence of a cookware on the cooking device based on the self-capacitance and / or mutual capacitance. When obtaining the self-capacitance, the capacitance-to-digital conversion circuit outputs an excitation to the electrode and simultaneously receives the signal from the electrode itself. When obtaining the mutual capacitance, two electrodes form a planar mutual capacitance plate. The capacitance-to-digital conversion circuit outputs an excitation to one electrode and receives the signal from the other electrode. Placing a pot on the electrode causes a sudden change in self-capacitance and / or mutual capacitance. The change in capacitance value determines whether a pot or kettle is above the electrode. Mutual capacitance is mainly used to eliminate the influence of temperature, achieving a high signal-to-noise ratio. The detection scheme is simple in structure due to the ease of electrode placement and low cost. The self-capacitance electrode generates a divergent electric field, and / or mutual capacitance forms a planar electric field. The electrode extends from the outer ring of the heating device 5 towards the center, resulting in high signal detection intensity and improved sensitivity. It has good detection effects on iron pots, glass kettles, or small pots.

[0024] As an improvement, the sensing electrodes 4 are configured with at least three, forming mutual capacitances in pairs, and are evenly distributed around the heating device 5, enabling further detection of whether the cookware is placed correctly. The cooking equipment can be further equipped with a prompting device in the coupling processing module to provide a warning when the cookware is not placed correctly.

[0025] The ceramic glass heating panel of the electric ceramic cooker needs to withstand high temperatures and the weight of the cookware. Several springs are distributed around the heating element 5 at the bottom. The ceramic glass provides elastic support to ensure the panel won't deform due to thermal expansion and contraction or pressure during long-term use, and to absorb impact when the cookware is suddenly placed or moved, reducing the risk of breakage of the brittle glass / ceramic panel. Due to the structural characteristics of the electric ceramic cooker, the existing springs in the device can be reused as sensing electrodes 4 in the detection scheme, further simplifying the structure and process, reducing costs, and facilitating wiring. The length of the springs can be adapted to the size of the cookware to be detected, and when extension is needed, the springs have sufficient space to extend towards the base. Since the springs are distributed around the heating wires of the electric ceramic cooker's heating plate, to prevent the springs from bending due to heat and touching the heating wires, causing a short circuit, the spring material is made of a high-temperature resistant and conductive material. For further protection, a capacitor 31 is installed on the circuit board to filter out the AC frequency of the mains power. The capacitor 31 is a small capacitor with a withstand voltage of 100pF, which filters out the 50Hz AC power frequency. In foreign regions, it is designed for the local AC power frequency. The spring is coupled to the processing module through the capacitor 31 to achieve AC power frequency isolation in the event of a short circuit, thus achieving a higher level of safety performance.

[0026] Furthermore, a conductor for enhancing the capacitance signal can be provided on the spring. The conductor is coupled to the spring to enhance the self-capacitance and / or mutual capacitance signals, thereby improving sensitivity. Preferably, the conductor can be integrally formed with the spring as an extension of the spring; or the conductor can be separately provided from the spring, such as by attaching an iron sheet or conductive needle to the spring.

[0027] Furthermore, the capacitance-to-digital conversion circuit couples each sensing electrode 4 through the switch array 32, which can effectively utilize CDC channel resources and flexibly switch capacitance acquisition.

[0028] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit the scope of protection of this utility model. Although this utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this utility model without departing from the essence and scope of the technical solutions of this utility model.

Claims

1. A cooking device, comprising a housing, wherein the housing houses a processing module, a heating device, and a capacitive sensor, characterized in that: The capacitive sensor includes at least two sensing electrodes, each distributed around the heating device and extending from the outer edge of the heating device towards the center; the cooking device is equipped with a capacitance-to-digital conversion circuit, which is coupled to each of the sensing electrodes to obtain the self-capacitance of the sensing electrodes and / or the mutual capacitance formed by pairs of sensing electrodes; the processing module is coupled to the capacitance-to-digital conversion circuit and is used to output a detection signal indicating whether there is a pot or cookware on the cooking device based on the self-capacitance and / or mutual capacitance.

2. The cooking apparatus according to claim 1, characterized in that: The sensing electrodes are configured in a configuration of at least three.

3. The cooking apparatus according to claim 2, characterized in that: Each sensing electrode is evenly distributed around the heating device.

4. The cooking apparatus according to claim 1, characterized in that: The sensing electrode extends inward from the outer ring of the heating device by at least 1 / 6 of the radius of the heating device.

5. The cooking apparatus according to claim 1, characterized in that: The cooking device is an electric ceramic stove. The top surface of the shell has a heating panel, and the bottom of the heating panel has several springs. Each spring is distributed around the heating device to elastically support the heating panel. The springs are reused as the sensing electrodes.

6. The cooking apparatus according to claim 5, characterized in that: The spring is made of a high-temperature resistant and conductive material.

7. The cooking apparatus according to claim 5 or 6, characterized in that: It includes a capacitor for filtering out AC mains frequencies, and the spring is coupled to the processing module via the capacitor.

8. The cooking apparatus according to claim 5, characterized in that: The spring is provided with a conductor for enhancing the capacitance signal, and the conductor is coupled to the spring.

9. The cooking apparatus according to claim 8, characterized in that: The conductor is integrally formed with the spring as an extension of the spring; or the conductor and the spring are separate components.

10. The cooking apparatus according to claim 1, characterized in that: The capacitor-to-digital converter circuit couples each sensing electrode separately through a switch array.

11. The cooking apparatus according to claim 2, characterized in that: The device includes a prompting mechanism for the coupling processing module.

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