A dual electrode temperature compensated cooking apparatus

Abstract

The utility model relates to a kind of double electrode temperature compensation cooking equipment, including base and the panel for placing cookware, panel covers on base, base is built-in processing module, heating furnace tray, at least one capacitance detection module is equipped in the furnace tray interior space of heating furnace tray, each capacitance detection module has the detection electrode for sensing cookware, wherein at least one capacitance detection module is equipped with reference electrode for sensing the temperature around detection electrode, the distance of reference electrode top surface from panel is less than the distance of detection electrode top surface from panel to form height difference;Capacitance digital conversion circuit is built-in in base, capacitance digital conversion circuit is respectively coupled each electrode, for obtaining the single-end self-capacitance of each detection electrode and reference electrode or the differential self-capacitance of detection electrode and reference electrode formed;Processing module is coupled capacitance digital conversion circuit, for the detection signal of outputting whether there is cookware on double electrode temperature compensation cooking equipment according to the differential result of the self-capacitance of detection electrode and reference electrode.

Description

Technical Field

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

[0002] Ceramic cooktops use resistance heating to cook food. 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 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. The detection is not limited to the placement of metal pots. However, since the capacitance is concentrated between the two plates, the capacitance change is small, resulting in low detection sensitivity. It is difficult to detect small pots with a bottom of less than 10cm. Utility Model Content

[0005] To address the shortcomings of existing technologies, a dual-electrode temperature-compensated cooking device is provided.

[0006] The cooking device of this utility model includes a base and a panel for placing cookware. The panel covers the base. The base has a built-in processing module and a heating plate. The heating plate has at least one capacitance detection module inside its internal space. Each capacitance detection module has a detection electrode for sensing the cookware. At least one capacitance detection module has a reference electrode for sensing the temperature around the detection electrode. The distance between the top surface of the reference electrode and the panel is less than the distance between the top surface of the detection electrode and the panel, thus forming a height difference. The base has a built-in capacitance-to-digital conversion circuit, which is coupled to each electrode to obtain the single-ended self-capacitance of each detection electrode and the reference electrode, or the differential self-capacitance formed by the detection electrode and the reference electrode. The processing module is coupled to the capacitance-to-digital conversion circuit to output a detection signal indicating whether cookware is present on the dual-electrode temperature-compensated cooking device based on the differential result of the self-capacitance between the detection electrode and the reference electrode.

[0007] The cooking device of this utility model also includes the following auxiliary technical solutions:

[0008] The height difference between the top surfaces of the reference electrode and the detection electrode is at least 0.5 cm.

[0009] The reference electrode and the detection electrode have the same projected area and shape relative to the panel.

[0010] In this case, the projected areas of the reference electrode and the detection electrode relative to the panel are misaligned or overlapped.

[0011] The heating plate has a resistance wire arranged at its bottom. The dual-electrode temperature-compensated cooking device has a power supply and a selector switch. The resistance wire is switched between the capacitor-to-digital converter circuit and the power supply via the selector switch in a time-sharing manner. The resistance wire serves as a multiplexed element for both the heating element and the reference electrode. The selector switch is a relay.

[0012] The capacitor detection module is located at the center of the heating furnace plate.

[0013] The capacitor detection module has at least three modules, which are evenly distributed around the center of the heating furnace plate.

[0014] This includes a switch array, and a capacitance-to-digital conversion circuit that couples each detection electrode through the switch array to obtain the self-capacitance of each detection electrode and / or the mutual capacitance formed by two detection electrodes.

[0015] This includes a prompting device for the coupling processing module.

[0016] The cooking device of this invention has electrodes arranged inside the heating plate to form a self-capacitive diverging electric field, resulting in high signal detection strength and improved sensitivity. It has a good detection effect on iron pots, glass kettles, or small pots. The electrodes are located inside the heating plate, and the temperature around the detection electrodes is sensed by setting a reference electrode, forming a height difference. The pots or kettles have different degrees of influence on the two. The temperature interference is eliminated by using the difference between the two while retaining the effective signal of the pots or kettles, ensuring the accuracy of detection. Attached Figure Description

[0017] Figure 1 A top view of the heating furnace plate of this utility model is provided.

[0018] Figure 2 A schematic diagram of the first arrangement of electrodes inside the heating furnace plate is given.

[0019] Figure 3 A schematic diagram of a second arrangement of electrodes inside the heating furnace plate is given.

[0020] Figure 4 A schematic diagram of a third arrangement of electrodes inside the heating furnace plate is given. 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] Cooking appliances such as electric ceramic cooktops consist of a base and a heating panel, with the heating panel covering the top of the base for placing cookware. See Figures 1 to 4 The base houses a heating plate 10 and a control circuit board. Resistance wires 11 are arranged at the bottom of the heating plate 10 for resistance heating. The control circuit board contains a chip 20, which integrates a processing module and a capacitance-to-digital converter (CDC) circuit. The capacitance-to-digital converter circuit, 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 and comparing it with a reference capacitance (see US Patent Number: 5,134,401). This improves the measurement sensitivity to the capacitance to the 1ff level and provides multiple channels, simplifying the circuit design.

[0023] A capacitance detection module 12 is installed inside the heating pan 10. The capacitance detection module 12 can be a single module, located at the center of the heating pan, or... Figure 1 As shown, three or more capacitance detection modules 12 are set up, with each module evenly distributed around the center of the heating furnace plate. (Reference) Figure 2 , Figure 3 Each capacitance detection module 12 has a detection electrode 121 for sensing the cookware. At least one capacitance detection module 12 is provided with a reference electrode 122 for sensing the temperature around the detection electrode 121. The distance between the top surface of the reference electrode 122 and the panel is less than the distance between the top surface of the detection electrode 121 and the panel, thus forming a height difference. The capacitance-to-digital conversion circuit is coupled to each electrode through twisted pair 30 to obtain single-ended self-capacitance or differential self-capacitance formed by the detection electrode and the reference electrode. The processing module is coupled to the capacitance-to-digital conversion circuit to output a detection signal for the presence or absence of cookware on the dual-electrode temperature-compensated cooking device based on the differential result of the self-capacitance between the detection electrode 121 and the reference electrode 122.

[0024] When acquiring self-capacitance, the CDC outputs excitation to the electrodes and receives the received value as single-ended self-capacitance from the electrodes themselves. When acquiring differential self-capacitance, the two electrodes are connected to the differential channel of the CDC, and the CDC directly outputs the differential result. During operation, placing a pot on the electrode causes a sudden change in self-capacitance. The presence of a pot or kettle above the electrode is determined based on the change in capacitance. Because the electrodes are arranged inside the heating plate 10, forming a divergent electric field of self-capacitance, the signal detection strength is high, the sensitivity is improved, and it has a good detection effect on iron pots, glass kettles, or small pots. The electrodes are located inside the heating plate 10, and high temperature affects the detection. By setting a reference electrode 122 to sense the temperature around the detection electrode 121 and forming a height difference, the pot or kettle has different degrees of influence on the two. The difference between the two is used to eliminate temperature common-mode noise while retaining the effective capacitance change of the pot or kettle, ensuring detection accuracy.

[0025] In this invention, the reference electrode 122 and the detection electrode 121 have the same projected area and shape relative to the panel, resulting in high consistency in temperature compensation. The projected areas of the reference electrode 122 and the detection electrode 121 relative to the panel are staggered, such as... Figure 4 As shown, to reduce spatial coupling interference, or, the projected areas of the two relative panels overlap, such as... Figure 2 As shown, this reduces the temperature gradient difference between the two electrodes.

[0026] The capacitance detection module 12 has only one located at the center of the heating plate, with electric field lines radiating outwards from the center, forming a single-center detection structure, reducing the number of electrodes and wiring complexity. Alternatively, at least three capacitance detection modules 12 can be evenly distributed around the center of the heating plate to achieve wide coverage and adapt to a wider variety of cookware. Based on the evenly distributed capacitance detection modules 12, the chip 20 has a built-in switch array. The capacitance-to-digital conversion circuit couples each detection electrode 121 through the switch array to obtain the self-capacitance of each detection electrode 121 and / or the mutual capacitance formed by pairs of detection electrodes 121, further detecting whether the cookware is placed correctly. The cooking device can be further equipped with a prompting device for the coupled processing module to provide a prompt when the cookware is not placed correctly.

[0027] As an improvement, the height difference between the top surfaces of the reference electrode 122 and the detection electrode 121 is at least 0.5 cm, ensuring that the pot has a much greater impact on the capacitance of the detection electrode 121 than on the reference electrode 122, thereby improving the signal-to-noise ratio.

[0028] As another improvement, the dual-electrode temperature-compensated cooking device has a power supply and a selector switch. The resistance wire 11 is switched between the capacitor digital conversion circuit and the power supply via the selector switch in a time-sharing manner. The resistance wire 11 serves as a multiplexed element for both the heating element and the reference electrode 122, saving hardware costs and space. At the same time, the time-sharing design avoids signal interference. Furthermore, a relay is used as the selector switch to achieve high isolation and withstand voltage, ensuring reliable detection.

[0029] 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 dual-electrode temperature-compensated cooking device, The system includes a base and a panel for placing cookware, the panel covering the base, and a built-in processing module and heating plate. Its features include: The heating plate has at least one capacitance detection module in its internal space. Each capacitance detection module has a detection electrode for sensing the cookware. At least one capacitance detection module has a reference electrode for sensing the temperature around the detection electrode. The distance between the top surface of the reference electrode and the panel is less than the distance between the top surface of the detection electrode and the panel, thus forming a height difference. The base has a built-in capacitor-to-digital converter circuit, which is coupled to each electrode to obtain the single-ended self-capacitance of each detection electrode and the reference electrode or the differential self-capacitance formed by the detection electrode and the reference electrode. The processing module is coupled with a capacitor-to-digital converter circuit, which is used to output a detection signal indicating whether there is a cookware on the dual-electrode temperature-compensated cooking device based on the difference in self-capacitance between the detection electrode and the reference electrode.

2. The dual-electrode temperature-compensated cooking device according to claim 1, characterized in that: The height difference between the top surfaces of the reference electrode and the detection electrode should be at least 0.5 cm.

3. The dual-electrode temperature-compensated cooking device according to claim 1, characterized in that: The reference electrode and the detection electrode have the same projected area and shape relative to the panel.

4. The dual-electrode temperature-compensated cooking device according to claim 1, characterized in that: The projected areas of the reference electrode and the detection electrode relative to the panel are misaligned or overlapped.

5. The dual-electrode temperature-compensated cooking device according to claim 1, characterized in that: The heating pan has a resistance wire arranged on its bottom. The dual-electrode temperature-compensated cooking device has a power supply and a selector switch. The resistance wire is switched between the capacitor digital conversion circuit and the power supply in a time-division manner through the selector switch. The resistance wire serves as a multiplexed element for both the heating element and the reference electrode.

6. The dual-electrode temperature-compensated cooking device according to claim 5, characterized in that: The selector switch is a relay.

7. The dual-electrode temperature-compensated cooking device according to claim 1, characterized in that: The capacitance detection module is located at the center of the heating furnace plate.

8. The dual-electrode temperature-compensated cooking device according to claim 1, characterized in that: The capacitance detection module has at least three modules, which are evenly distributed around the center of the heating furnace plate.

9. The dual-electrode temperature-compensated cooking device according to claim 8, characterized in that: It includes a switch array, and a capacitance-to-digital conversion circuit couples each detection electrode through the switch array to obtain the self-capacitance of each detection electrode and / or the mutual capacitance formed by two detection electrodes.

10. The dual-electrode temperature-compensated cooking device according to claim 9, characterized in that: The device includes a prompting mechanism for the coupling processing module.

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