A pot detection circuit, method and electromagnetic cooker for a global heating electromagnetic cooker
The detection method for induction cookers with full-area heating, achieved through a coupled feedback loop and MCU control, solves the problem of intermittent non-heating when detecting cookware, improves heating efficiency and user experience, and realizes uninterrupted cookware detection and heating.
Patent Information
- Application Number
- CN202510932905.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-08
- Publication Date
- 2026-02-10
- Estimated Expiration
- 2045-07-08
AI Technical Summary
Existing induction cooktops with full-area heating exhibit intermittent heating failures when detecting cookware, resulting in low heating efficiency. This is especially problematic in multi-LC resonant circuits where the polling time is excessively long, negatively impacting the user experience.
A coupled feedback loop is used to receive the pulse detection signal from the MCU control unit, which excites the LC resonant circuit to generate an equivalent impedance. The presence of the cookware is determined by the feedback signal, and the inverter circuit is turned on to generate a high-frequency square wave voltage, which drives the induction coil to generate an alternating magnetic field to form eddy current to heat the cookware.
It enables rapid detection of cookware without switching the electronic switch, improving heating efficiency, reducing system losses, and enhancing user experience without affecting normal heating.
Smart Images
Figure CN120447066B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of electromagnetic heating technology, and in particular to a cookware detection circuit, method, and electromagnetic stove for a full-range heating electromagnetic stove. Background Technology
[0002] In the existing technology, each burner of the all-area heating induction cooker is equipped with an array of LC resonant circuits. All LC resonant circuits of each burner are connected to an inverter. The inverters of multiple burners are connected in parallel or not in parallel through electronic switches, so that a single LC resonant circuit can work when not connected in parallel, or multiple LC resonant circuits can work simultaneously when connected in parallel, thus meeting the power output requirements of different cookware and different heating needs.
[0003] However, existing induction cooktops with full-area heating require the electronic switch to switch at zero voltage and zero current when polling to detect the coil position and output heating power. This causes the inverter to pause operation first, which in turn stops the oscillation of the LC resonant circuit that is heating, resulting in intermittent heating failure. Furthermore, when a certain LC resonant circuit is working, if the user randomly places a pot on it and uses a polling method to detect whether there is a pot on other LC resonant circuits, the more LC resonant circuits there are, the longer the polling time and the longer the intermittent time become, resulting in poorer heating efficiency of the full-area heating induction cooktop, which seriously affects the user experience. Summary of the Invention
[0004] In view of the above-mentioned defects or deficiencies in the related technologies, the purpose of this application is to provide a cookware detection circuit, method and induction cooker for a full-area heating induction cooker, which can continuously detect whether there is a cookware on the induction coil of multiple LC resonant circuits of the full-area heating, which can effectively improve the heating efficiency of the full-area heating induction cooker and thus improve the user experience.
[0005] To achieve the above objectives, this application provides the following solution:
[0006] In a first aspect, this application provides a cookware detection method for a full-range heating induction cooker, comprising: multiple sets of LC resonant circuits and an MCU control unit, wherein any set of LC resonant circuits is connected to a coupling feedback circuit and an inverter circuit;
[0007] The first output terminal of the MCU control unit is connected to the input terminal of the coupling feedback loop; the first output terminal of the coupling feedback loop is connected to the LC resonant loop; the second output terminal of the coupling feedback loop is connected to the input terminal of the MCU control unit; the second output terminal of the MCU control unit is connected to the LC resonant loop; the third output terminal of the MCU control unit is connected to the input terminal of the inverter loop; the output terminal of the inverter loop is connected to the LC resonant loop; when the all-area heating induction cooker is in the powered-on state, the coupling feedback loop receives the pulse detection signal sent by the MCU control unit and excites the LC resonant loop based on the pulse detection signal. The LC resonant circuit generates an equivalent impedance and a feedback signal based on the equivalent impedance. The MCU control unit is used to determine whether there is a pot on the induction coil of the LC resonant circuit based on the feedback signal. If there is a pot, the inverter circuit and the LC resonant circuit are turned on, and a heating control signal is generated and sent to the inverter circuit. The inverter circuit is used to generate a high-frequency square wave voltage based on the heating control signal and to drive the induction coil of the LC resonant circuit to generate an alternating magnetic field based on the high-frequency square wave voltage. The LC resonant circuit is used to form a closed loop with the pot in the alternating magnetic field to generate eddy currents and to heat the pot based on the eddy currents.
[0008] Optionally, the LC resonant circuit includes a resistor Rs1_1, an induction coil L1_1, and a relay K1_1; wherein, one end of the resistor Rs1_1 is connected to the first output terminal of the coupled feedback circuit, and the other end of the resistor Rs1_1 is connected to one end of the induction coil L1_1; the other end of the induction coil L1_1 is connected to one end of the relay K1_1, the other end of the relay K1_1 is connected to the output terminal of the inverter circuit, and the input terminal of the relay K1_1 is connected to the second output terminal of the MCU control unit; the relay K1_1 is used to conduct the inverter circuit and the LC resonant circuit under the control of the MCU control unit; the induction coil L1_1 is used to generate an alternating electromagnetic field under the drive of a high-frequency square wave voltage when the relay K1_1 is in the energized state, and to form a closed loop with the pot placed on the induction coil L1_1 to generate eddy current.
[0009] Optionally, the coupling feedback loop includes: capacitor C10_3, capacitor C10_4, capacitor C10_5, and comparator U1; wherein, one end of capacitor C10_3 is connected to the first output terminal of the MCU control unit, the other end of capacitor C10_3 is connected to one end of capacitor C10_5, the other end of capacitor C10_5 is connected to one end of capacitor C10_4, and the other end of capacitor C10_4 is connected to the input terminal of the LC resonant circuit; the midpoint of the connection between capacitors C10_3 and C10_5 is a detection point, and the detection point is connected to the positive input terminal of comparator U1; the negative input terminal of comparator U1 is connected to the MCU control unit. The fourth output terminal of the control unit is connected, and the output terminal of the comparator U1 is connected to the input terminal of the MCU control unit. When the relay K1_1 is open, the capacitors C10_3, C10_4, and C10_ form a coupling circuit. The coupling circuit is used to couple the pulse detection signal to generate a coupling signal, and based on the coupling signal, the LC resonant circuit is excited to generate an equivalent impedance, and a detection signal is generated at the detection point under the action of the equivalent impedance. The comparator U1 is used to compare the detection signal with the reference voltage output by the MCU control unit to generate a feedback signal. The feedback signal is a square wave signal with different duty cycles.
[0010] Optionally, the coupling feedback loop further includes: diode D10_1 and resistor R10_6; the detection point is connected to the positive input terminal of comparator U1 through diode D10_1 and resistor R10_6; diode D10_1 is used to filter the negative pulse voltage of the detection signal so that the detection signals input to comparator U1 are all positive pulse voltages.
[0011] Optionally, the coupling feedback loop further includes: resistor R10_2, transistor Q1, and resistor R10_3; one end of resistor R10_2 is connected to the first output terminal of the MCU control unit, one end of resistor R10_2 is connected to the base of transistor Q1, the emitter of transistor Q1 is grounded, the collector of transistor Q1 is connected to one end of capacitor C10_3 and resistor R10_3 respectively, the other end of resistor R10_3 is connected to VCC, and capacitor C10_3 is connected to the first output terminal of the MCU control unit through resistor R10_2 and the collector of transistor Q1; resistor R10_2, transistor Q1, and resistor R10_3 form an inverting amplification loop, which is used to invert and amplify the pulse detection signal output by the MCU control unit, and output the inverted amplified pulse detection signal to capacitor C10_3.
[0012] Optionally, any one of the LC resonant circuits is further connected to a first driving circuit and a second driving circuit; the inverter circuit includes a first inverter circuit and a second inverter circuit; the first inverter circuit and the second inverter circuit are connected in series; the first inverter circuit and the second inverter circuit are connected in series to form the midpoint of a bridge arm, and the midpoint of the bridge arm serves as the input terminal of the inverter circuit and is connected to the LC resonant circuit; the third output terminal OUTA1 of the MCU control unit is connected to the input terminal of the first inverter circuit through the first driving circuit, and the third output terminal OUTB1 of the MCU control unit is connected to the input terminal of the second inverter circuit through the second driving circuit; the MCU control unit outputs a first heating control signal to the first inverter circuit through the first driving circuit; and outputs a second heating control signal to the second inverter circuit through the second driving circuit; the first heating control signal and the second heating control signal are complementary square wave signals; the first inverter circuit and the second inverter circuit are used to work alternately under the drive of two sets of complementary square wave signals to generate a high-frequency square wave voltage.
[0013] Optionally, the first drive circuit includes a resistor R3, a driver U2, and a resistor R5; one end of the resistor R5 is connected to the third output terminal OUTA1 of the MCU control unit, the other end of the resistor R5 is connected to the input terminal of the driver U2, the output terminal of the driver U2 is connected to one end of the resistor R3, and the other end of the resistor R3 is connected to the input terminal of the first inverter circuit; the first drive circuit is used to amplify the first heating control signal and output the amplified first heating control signal to the first inverter circuit; the second drive circuit includes a resistor R4, a driver U3, and a resistor R6; one end of the resistor R6 is connected to the third output terminal OUTB1 of the MCU control unit, the other end of the resistor R6 is connected to the input terminal of the driver U3, the output terminal of the driver U3 is connected to one end of the resistor R4, and the other end of the resistor R4 is connected to the input terminal of the second inverter circuit; the second drive circuit is used to amplify the second heating control signal and output the amplified second heating control signal to the second inverter circuit.
[0014] Secondly, this application provides a cookware detection method for a full-range heating induction cooker, the method being applied to the MCU control unit described in any of the above claims, the method comprising:
[0015] When the induction cooker with full-area heating is powered on, a pulse detection signal is sent to the coupling feedback loop; and the feedback signal output by the coupling feedback loop is acquired; based on the feedback signal, it is determined whether there is a pot on the induction coil of the LC resonant loop; if there is a pot, the inverter loop and the LC resonant loop are turned on, and a heating control signal is generated and sent to the inverter loop, so that the inverter loop generates a high-frequency square wave voltage based on the heating control signal, and drives the induction coil of the LC resonant loop to generate an alternating magnetic field based on the high-frequency square wave voltage; the LC resonant loop forms a closed loop with the pot in the alternating magnetic field to generate eddy currents, and heats the pot based on the eddy currents.
[0016] Optionally, the feedback signal is a square wave signal with different duty cycles; the step of determining whether there is a pot on the induction coil of the LC resonant circuit based on the feedback signal includes: reading the duty cycle value of the feedback signal; if the duty cycle of the feedback signal is greater than the reference duty cycle value, there is a pot on the induction coil of the LC resonant circuit; if the duty cycle of the feedback signal is less than or equal to the reference duty cycle value, there is no pot on the induction coil of the LC resonant circuit.
[0017] Thirdly, this application provides a full-range heating induction cooker, including a control board, wherein the control board integrates a cookware detection circuit for the full-range heating induction cooker as described in any of the above claims, or the control board is used to execute the cookware detection method for the full-range heating induction cooker as described in any of the above claims.
[0018] According to the specific embodiments provided in this application, the following technical effects are disclosed:
[0019] This application provides a cookware detection circuit, method, and induction cooker for a full-range heating induction cooker. It receives a pulse detection signal from an MCU control unit via a coupled feedback loop, and excites an LC resonant circuit to generate an equivalent impedance based on the pulse detection signal, and generates a feedback signal based on the equivalent impedance. The MCU control unit receives the feedback signal and determines whether a cookware is present on the induction coil of the LC resonant circuit. If a cookware is present, the inverter circuit and the LC resonant circuit are activated, and a heating control signal is generated and sent to the inverter circuit. The heating control signal drives the inverter circuit to generate a high-frequency square wave voltage. The voltage-driven induction coil of the LC resonant circuit generates an alternating magnetic field. This LC resonant circuit forms a closed loop with the cookware within the alternating magnetic field, generating eddy currents, which then heat the cookware. This allows the system to detect whether a normal cookware is placed on the induction coil of other LC resonant circuits without switching electronic switches, even when a cookware is already heating on the induction coil of the induction cooker. This avoids affecting the already heated cookware and effectively improves the heating efficiency of the induction cooker. Furthermore, the detection process is unaffected by the number of LC resonant circuits, offering advantages such as low system loss and high detection efficiency, thus significantly improving the user experience. Attached Figure Description
[0020] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0021] Figure 1 This application provides a schematic diagram of a cookware detection circuit for a full-range heating induction cooker.
[0022] Figure 2 This application provides a circuit diagram for detecting cookware in a full-range heating induction cooker;
[0023] Figure 3 This is a flowchart illustrating a method for detecting cookware in a full-range heating induction cooker according to an embodiment of this application.
[0024] Figure 4 This application provides a functional module diagram of an induction cooker with full-area heating. Detailed Implementation
[0025] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0026] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the technical solutions claimed in this application will be further described in detail below with reference to the accompanying drawings and specific embodiments.
[0027] In one exemplary embodiment, such as Figure 1 As shown, a cookware detection circuit for a full-range heating induction cooker is provided. This circuit may include multiple LC resonant circuits 20 and an MCU control unit 10. Each LC resonant circuit 20 is connected to a coupling feedback circuit 30 and an inverter circuit 40. Specifically, the first output terminal of the MCU control unit 10 is connected to the input terminal of the coupling feedback circuit 30; the first output terminal of the coupling feedback circuit 30 is connected to the LC resonant circuit 20; the second output terminal of the coupling feedback circuit 30 is connected to the input terminal of the MCU control unit 10; the second output terminal of the MCU control unit 10 is connected to the LC resonant circuit 20; the third output terminal of the MCU control unit 10 is connected to the input terminal of the inverter circuit 40; and the output terminal of the inverter circuit 40 is connected to the LC resonant circuit 20.
[0028] When the induction cooker with full-area heating is powered on, the coupling feedback loop 30 receives the pulse detection signal sent by the MCU control unit 10, and excites the LC resonant loop 20 to generate an equivalent impedance based on the pulse detection signal, and generates a feedback signal based on the equivalent impedance. The MCU control unit 10 determines whether there is a pot on the induction coil of the LC resonant loop 20 based on the feedback signal. If there is a pot, the inverter loop 40 and the LC resonant loop 20 are turned on, and a heating control signal is generated and sent to the inverter loop 40. The inverter loop 40 generates a high-frequency square wave voltage based on the heating control signal, and drives the induction coil of the LC resonant loop 20 to generate an alternating magnetic field based on the high-frequency square wave voltage.
[0029] It should be noted that the pulse detection signal sent by the MCU control unit 10 is received through the coupling feedback loop 30, and the equivalent impedance is generated based on the pulse detection signal to excite the LC resonant loop 20, and a feedback signal is generated based on the equivalent impedance. The MCU control unit 10 receives the feedback signal and determines whether there is a pot on the induction coil of the LC resonant loop 20. If there is a pot, the inverter loop 40 and the LC resonant loop 20 are turned on, and a heating control signal is generated and sent to the inverter loop 40. The heating control signal drives the inverter loop 40 to generate a high-frequency square wave voltage, and the high-frequency square wave voltage drives the LC resonant loop 20 to generate a high-frequency square wave voltage. The induction coil of the LC resonant circuit 20 generates an alternating magnetic field. Through the LC resonant circuit 20 forming a closed loop with the cookware in the alternating magnetic field, eddy currents are generated, and the cookware is heated based on these eddy currents. This allows for the detection of whether a normal cookware is placed on the induction coil of other LC resonant circuits 20 when a cookware is already heating on the induction cooker, without switching electronic switches. This avoids affecting the already heated cookware and effectively improves the heating efficiency of the induction cooker. Furthermore, the detection process is unaffected by the number of LC resonant circuits 20, offering advantages such as low system loss and high detection efficiency, effectively enhancing the user experience.
[0030] Furthermore, such as Figure 2 As shown, the LC resonant circuit 20 includes a resistor Rs1_1, an induction coil L1_1, and a relay K1_1. One end of the resistor Rs1_1 is connected to the first output terminal of the coupling feedback circuit 30, and the other end of the resistor Rs1_1 is connected to one end of the induction coil L1_1. The other end of the induction coil L1_1 is connected to one end of the relay K1_1, and the other end of the relay K1_1 is connected to the output terminal of the inverter circuit 40. The input terminal of the relay K1_1 is connected to the second output terminal of the MCU control unit 10. Under the control of the MCU control unit, the relay K1_1 conducts the inverter circuit and the LC resonant circuit. When the relay K1_1 is in the energized state, the induction coil L1_1 generates an alternating electromagnetic field under the drive of a high-frequency square wave voltage, and forms a closed loop with the pot placed on the induction coil L1_1 in the alternating electromagnetic field to generate eddy current.
[0031] Furthermore, such as Figure 2As shown, the above-mentioned coupled feedback loop 30 includes: capacitor C10_3, capacitor C10_4, capacitor C10_5, and comparator U1; wherein, one end of capacitor C10_3 is connected to the CHECK_PWM pin of the MCU control unit 10, the other end of capacitor C10_3 is connected to one end of capacitor C10_5, the other end of capacitor C10_5 is connected to one end of capacitor C10_4, and the other end of capacitor C10_4 is connected to the input terminal of the LC resonant circuit 20; the midpoint of the connection between capacitors C10_3 and C10_5 is detection point A, and detection point A is connected to the positive input terminal of comparator U1; the negative input terminal of comparator U1 is connected to the MCU control unit 10. The fourth output terminal of the control unit 10 is connected, and the output terminal of comparator U1 is connected to the LOAD1 pin of the MCU control unit 10. When relay K1_1 is off, capacitors C10_3, C10_4, and C10_5 form a coupling circuit. The coupling circuit is used to couple the pulse detection signal to generate a coupling signal, and excites the LC resonant circuit 20 to generate an equivalent impedance based on the coupling signal. Under the action of the equivalent impedance, a detection signal is generated at the detection point A. Comparator U1 compares the detection signal with the reference voltage output by the MCU control unit 10 to generate a feedback signal. The feedback signal is a square wave signal with different duty cycles.
[0032] It should be noted that when the pulse detection signal output by the MCU control unit 10 is injected into the LC resonant circuit 20 through the coupling circuit, the rising and falling edges of the pulse detection signal will excite the LC resonant circuit 20 to generate a transient response; that is, if there is no pot: the impedance of the LC resonant circuit 20 is low, the transient response is characterized by rapid oscillation decay, and the detection signal edge is steep; if there is a pot: the impedance of the LC resonant circuit 20 is high, the transient response decays faster, and the detection signal edge becomes gentler.
[0033] Furthermore, such as Figure 2 As shown, the coupling feedback loop 30 further includes a diode D10_1 and a resistor R10_6; wherein, detection point A is connected to the positive input terminal of comparator U1 through diode D10_1 and resistor R10_6; the anode of diode D10_1 is connected to detection point A, the cathode of diode D10_1 is connected to one end of resistor R10_6, and the other end of resistor R10_6 is connected to the positive input terminal of comparator U1; diode D10_1 is used to filter the negative pulse voltage of the detection signal so that the detection signal input to comparator U1 is always a positive pulse voltage.
[0034] Furthermore, such as Figure 2As shown, the coupling feedback loop 30 also includes: resistor R10_2, transistor Q1, and resistor R10_3; wherein, one end of resistor R10_2 is connected to the first output terminal of MCU control unit 10, one end of resistor R10_2 is connected to the base of transistor Q1, the emitter of transistor Q1 is grounded, the collector of transistor Q1 is connected to capacitor C10_3 and one end of resistor R10_3 respectively, the other end of resistor R10_3 is connected to VCC, and capacitor C10_3 is connected to the first output terminal of MCU control unit 10 through resistor R10_2 and the collector of transistor Q1.
[0035] It should be noted that resistor R10_2, transistor Q1, and resistor R10_3 form an inverting amplification circuit. This circuit amplifies the pulse detection signal output from the MCU control unit 10 and outputs the amplified signal to capacitor C10_3. The first output of the MCU control unit 10 is the CHECK_PWM pin, the second output is the JDQ1 pin, and the third outputs are the OUTA1 and OUTB1 pins. The input of the MCU control unit 10 is the LOAD1 pin.
[0036] In some specific implementation methods, such as Figure 2 As shown, each set of LC resonant circuits 20 is also connected to a drive circuit 50, which includes a first drive circuit and a second drive circuit; the inverter circuit 40 includes a first inverter circuit and a second inverter circuit; the first inverter circuit and the second inverter circuit are connected in series; the first inverter circuit and the second inverter circuit are connected in series to form the midpoint B of the bridge arm, and the midpoint B of the bridge arm serves as the input terminal of the inverter circuit 40 and is connected to the LC resonant circuit 20; the third output terminal OUTA1 of the MCU control unit 10 is connected to the input terminal of the first inverter circuit through the first drive circuit, and the third output terminal OUTB1 of the MCU control unit 10 is connected to the input terminal of the second inverter circuit through the second drive circuit; the MCU control unit 10 outputs a first heating control signal to the first inverter circuit through the first drive circuit; and outputs a second heating control signal to the second inverter circuit through the second drive circuit; the first heating control signal and the second heating control signal are complementary square wave signals; the first inverter circuit and the second inverter circuit are used to work alternately under the drive of the two sets of complementary square wave signals to generate a high-frequency square wave voltage.
[0037] It should be noted that the first inverter circuit and the second inverter circuit involved in this application are both IGBT (Insulated Gate Bipolar Transistor) power circuits. In other embodiments, MOSFET power circuits or SiC MOSFET power circuits may also be used.
[0038] Furthermore, such as Figure 2As shown, the first drive circuit includes resistor R3, driver U2, and resistor R5; one end of resistor R5 is connected to the third output terminal OUTA1 of MCU control unit 10, the other end of resistor R5 is connected to the input terminal of driver U2, the output terminal of driver U2 is connected to one end of resistor R3, and the other end of resistor R3 is connected to the input terminal of the first inverter circuit; the second drive circuit includes resistor R4, driver U3, and resistor R6; one end of resistor R6 is connected to the third output terminal OUTB1 of MCU control unit 10, the other end of resistor R6 is connected to the input terminal of driver U3, the output terminal of driver U3 is connected to one end of resistor R4, and the other end of resistor R4 is connected to the input terminal of the second inverter circuit.
[0039] It should be noted that the first drive circuit is used to amplify the first heating control signal and output the amplified first heating control signal to the first inverter circuit; the second drive circuit is used to amplify the second heating control signal and output the amplified second heating control signal to the second inverter circuit.
[0040] refer to Figure 2 As can be understood from the above embodiments, the external AC power supply, after rectification, is connected to both ends of capacitor C1, namely DC+ and GND. Capacitors C10_1 and C10_2 are connected in series and then in parallel with capacitor C1. Resistor Rs1_1 represents the equivalent resistance of the induction coil L1_1 combined with the cookware. The values of resistor Rs1_1 and induction coil L1_1 change with the cookware. One end of resistor Rs1_1 is connected to the connection point of capacitors C10_1 and C10_2, and the other end of resistor Rs1_1 is connected to induction coil L1_1. The other end of induction coil L1_1 is connected to relay K1_1. The other end of relay K1_1 is connected to the midpoint of the bridge arm formed by the first inverter circuit and the second inverter circuit. The first inverter circuit includes capacitor C4 and IGBT1 (Insulated Gate Bipolar Transistor). The collector of IGBT1 is connected to the DC+ terminal of capacitor C1, and the gate of IGBT1 is connected to driver U2 via resistor R3. Capacitor C4 is connected in parallel with IGBT1. The second inverter circuit includes capacitor C5 and IGBT2. The gate of IGBT2 is connected to driver U3 via resistor R4. The collector of IGBT2 is connected to the emitter of IGBT1, and the emitter of IGBT2 is connected to the GND terminal of capacitor C1. Capacitor C5 is connected in parallel with IGBT2. Driver U2 is connected to the OUTA1 pin of MCU control unit 10 via resistor R5, and driver U3 is connected to the OUTB1 pin of MCU control unit 10 via resistor R6.
[0041] The CHECK_PWM pin of the MCU control unit 10 is connected to resistor R10_2. The CHECK_PWM pin of the MCU control unit 10 sends a PWM signal (pulse detection signal) to resistor R10_2. Transistor Q1 amplifies the PWM signal and applies it to capacitor C10_3. One end of capacitor C10_4 is connected to the midpoint between capacitors C10_1 and C10_2, and the other end of capacitor C10_4 is connected to capacitor C10_5. The other end of capacitor C10_5 is connected to capacitor C10_3, diode D10_1, and resistor R10. Phase 4 is connected, with the other end of resistor R10_4 connected to the GND terminal of capacitor C1, and the other end of diode D10_1 connected to resistor R10_6 and then entering the positive input terminal of comparator U1; the DAC_PWM pin of MCU control unit 10 is connected to resistor R10_7, the other end of resistor R10_7 is connected to capacitor C10_6 and then connected to the negative input terminal of comparator U1, and the other end of capacitor C10_6 is connected to GND; the output terminal of comparator U1 is connected to the LOAD1 pin of MCU control unit 10 through pull-up resistor R10_8. When relay K1_1 is energized, capacitors C1, C10_1, C10_2, resistor Rs1_1, induction coil L1_1, relay K1_1, capacitors C4 and C5, IGBT1 and IGBT2 form a typical half-bridge resonant inverter circuit. Among them, capacitors C10_1, C10_2, resistor Rs1_1, induction coil L1_1 and relay K1_1 form an LC oscillation circuit.
[0042] When the induction cooker with full-area heating is powered on, the detection process is as follows: When the induction cooker with full-area heating starts working, relay K1_1 remains open. The MCU control unit 10 first applies a PWM signal of a certain frequency and duty cycle to resistor R10_2 through the CHECK_PWM pin. After being amplified by transistor Q1, it is directly applied to capacitor C10_3. The rising edge of the PWM signal can be quickly coupled through capacitors C10_3, C10_5, and C10_4 to a set of LC oscillation circuits composed of capacitors C10_1, C10_2, resistor Rs1_1, induction coil L1_1, and relay K1_1. Since the LC oscillation circuit operates at a certain frequency, if a suitable pot is placed on induction coil L1_1, the value of resistor Rs1_1 increases accordingly. The rising edge spike of the detection signal applied to detection point A will decrease significantly, and the amplitude of the detection signal will decrease rapidly before slowly charging back to VCC. Considering that the detection signal will inevitably have a negative pulse at detection point A due to capacitive coupling, the detection signal is first deflected by diode D10_1 to remove the negative pulse voltage before being connected to the positive input of comparator U1. Simultaneously, the DAC_PWM pin of the MCU control unit 10 sets the reference voltage at the negative input of comparator U1 via D / A conversion. The output of comparator U1 outputs feedback signals (square wave signals) with different duty cycles based on the voltage signals at its positive and negative inputs. The MCU control unit 10 reads the change in the duty cycle value of the feedback signal through the LOAD1 pin to determine whether there is a suitable pot for heating placed on the induction coil L1_1 of the LC resonant circuit 20. If there is a suitable pot for heating on the induction coil L1_1, then the MCU control unit 10... By raising the voltage of the third output pin JDQ1, the corresponding relay K1_1 is energized. After a debounce delay, the first heating control signal driver U2 is output from the OUTA1 pin, and the second heating control signal is output from the OUTB1 pin to driver U3. Drivers U2 and U3 drive IGBT1 and IGBT2 to work alternately. When IGBT1 and IGBT2 work alternately, they will invert and generate a high-frequency current that flows through the induction coil L1_1. The induction coil L1_1 generates an alternating magnetic field, causing the pot on the induction coil L1_1 to heat up directly and start cooking. When there are multiple LC resonant circuits 20, the MCU control unit 10 can cyclically execute the above detection process on the corresponding LC resonant circuit 20.
[0043] Based on the same inventive concept, this application also provides a cookware detection method for a full-area heating induction cooker, which is applied to the cookware detection circuit of the full-area heating induction cooker involved in the above embodiments. The solution provided by this method is similar to the implementation scheme described in the cookware detection circuit of the full-area heating induction cooker. Therefore, the specific limitations in one or more embodiments of the cookware detection method for a full-area heating induction cooker provided below can be found in the limitations of the cookware detection circuit of the full-area heating induction cooker above, and will not be repeated here.
[0044] In one exemplary embodiment, such as Figure 3 As shown, a cookware detection method for a full-range heating induction cooker is provided. The execution subject of this method is the MCU control unit in the above embodiment. The method may include the following steps S301 to S303, specifically:
[0045] Step S301: With the induction cooker in full-area heating mode powered on, a pulse detection signal is sent to the coupling feedback loop; and the feedback signal output by the coupling feedback loop is acquired.
[0046] Step S302: Determine whether there is a pot on the induction coil of the LC resonant circuit based on the feedback signal;
[0047] In step S303, when a pot is present, the inverter circuit and the LC resonant circuit are turned on, and a heating control signal is generated and sent to the inverter circuit, so that the inverter circuit generates a high-frequency square wave voltage based on the heating control signal, and drives the induction coil of the LC resonant circuit to generate an alternating magnetic field based on the high-frequency square wave voltage; the LC resonant circuit forms a closed loop with the pot in the alternating magnetic field to generate eddy current, and heats the pot based on the eddy current.
[0048] As an optional implementation, the generation of the feedback signal in step S301 includes: when the full-range heating induction cooker is in the powered-on state, the inverting amplification circuit amplifies the pulse detection signal received from the MCU control unit and outputs the amplified pulse detection signal to the coupling circuit; the coupling circuit generates a coupling signal based on the pulse detection signal, and excites the LC resonant circuit to generate an equivalent impedance based on the coupling signal, and generates a detection signal at the detection point under the action of the equivalent impedance; the comparator U1 compares the detection signal with the reference voltage output by the MCU control unit to generate a feedback signal; the feedback signal is a square wave signal with different duty cycles.
[0049] It should be noted that the reference duty cycle involved in the embodiments of this application is the duty cycle value set inside the MCU control unit. The reference duty cycle value and reference voltage shall be based on the actual application, and the embodiments of this application do not impose specific limitations.
[0050] As an optional implementation, step S302 may include: reading the duty cycle value of the feedback signal; if the duty cycle of the feedback signal is greater than the reference duty cycle value, there is a pot on the induction coil of the LC resonant circuit; if the duty cycle of the feedback signal is less than or equal to the reference duty cycle value, there is no pot on the induction coil of the LC resonant circuit.
[0051] As an optional implementation, step S303 may include: outputting a first heating control signal to a first inverter circuit through a first drive circuit; outputting a second heating control signal to a second inverter circuit through a second drive circuit; the first heating control signal and the second heating control signal are complementary square wave signals; the first inverter circuit and the second inverter circuit work alternately under the drive of the two sets of complementary square wave signals to generate a high-frequency square wave voltage.
[0052] In this implementation, a pulse detection signal sent by the MCU control unit is received through a coupled feedback loop. This pulse detection signal excites the LC resonant circuit to generate an equivalent impedance, and a feedback signal is generated based on this equivalent impedance. The MCU control unit receives the feedback signal and determines whether a pot is on the induction coil of the LC resonant circuit. If a pot is present, the inverter circuit and the LC resonant circuit are activated, generating a heating control signal and sending it to the inverter circuit. The heating control signal drives the inverter circuit to generate a high-frequency square wave voltage, which in turn drives the induction coil of the LC resonant circuit to generate an alternating magnetic field. The LC resonant circuit forms a closed loop with the pot in the alternating magnetic field to generate eddy currents, which then heat the pot. This method allows for the detection of pots on the induction coils of other LC resonant circuits without switching electronic switches, even when pots are already heating in the all-area heating induction cooker. This avoids affecting pots already heating and effectively improves the heating efficiency of the all-area heating induction cooker. Furthermore, the detection process is unaffected by the number of LC resonant circuits, resulting in low system loss and high detection efficiency.
[0053] In one exemplary embodiment, such as Figure 4 As shown, a full-range heating induction cooker 400 is provided. The full-range heating induction cooker includes a control board 401, on which a cookware detection circuit of the full-range heating induction cooker in the above embodiment is integrated.
[0054] In one exemplary embodiment, the control board includes an MCU control unit, which is used to execute the cookware detection method for the all-area heating induction cooker described above.
[0055] 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.
[0056] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.
Claims
1. A cookware detection circuit for a full-range heating induction cooker, characterized in that, The circuit includes multiple sets of LC resonant circuits and an MCU control unit. Each set of LC resonant circuits is connected to a coupling feedback circuit and an inverter circuit. Each LC resonant circuit includes a resistor Rs1_1, an induction coil L1_1, and a relay K1_1. The coupling feedback loop includes: capacitors C10_3, C10_4, and C10_5; resistor R10_2; transistor Q1; resistor R10_3; diode D10_1; resistor R10_6; resistor R10_7; capacitor C10_6; resistor R10_8; and comparator U1. Diode D10_1 filters the negative pulse voltage of the pulse detection signal output by the MCU control unit, ensuring that all detection signals input to comparator U1 are positive pulse voltages. Resistor R10_2, transistor Q1, and resistor R10_3 form an inverting amplification loop, which amplifies the pulse detection signal in reverse and outputs the amplified pulse detection signal to capacitor C10_3. The inverter circuit includes a first inverter circuit and a second inverter circuit. The first inverter circuit and the second inverter circuit are connected in series to form the midpoint B of the bridge arm. The midpoint B of the bridge arm serves as the input terminal of the inverter circuit and is connected to the LC resonant circuit. In this configuration, the first output terminal CHECK_PWM of the MCU control unit is connected to one end of resistor R10_2, the other end of resistor R10_2 is connected to the base of transistor Q1, the emitter of transistor Q1 is grounded, the collector of transistor Q1 is connected to capacitor C10_3 and one end of resistor R10_3, the other end of resistor R10_3 is connected to VCC, the other end of capacitor C10_3 is connected to one end of capacitor C10_5, the other end of capacitor C10_5 is connected to one end of capacitor C10_4, and the other end of capacitor C10_4... The resistor Rs1_1 is connected to one end of the capacitor; the midpoint between the capacitors C10_3 and C10_5 is the detection point A, which is connected to the positive input terminal of the comparator U1 through the diode D10_1 and the resistor R10_6; the negative input terminal of the comparator U1 is connected to the fourth output terminal DAC_PWM of the MCU control unit through the resistor R10_7 and the capacitor C10_6, and the other end of the capacitor C10_6 is grounded; the output terminal of the comparator U1 is connected to the input terminal of the MCU control unit, LOAD1, through the resistor R10_8. The other end of the resistor Rs1_1 is connected to one end of the induction coil L1_1; the other end of the induction coil L1_1 is connected to one end of the relay K1_1; the other end of the relay K1_1 is connected to the midpoint B of the bridge arm of the inverter circuit; and the input terminal of the relay K1_1 is connected to the second output terminal of the MCU control unit. The third output terminal of the MCU control unit is connected to the input terminals of the first inverter circuit and the second inverter circuit, respectively. When the induction cooker with full-area heating is powered on, for any set of LC resonant circuits that are not conducting heating, relay K1_1 is in the open state. Capacitors C10_3, C10_4, and C10_5 form a coupling circuit. This coupling feedback circuit is used to receive the pulse detection signal sent by the MCU control unit. The coupling circuit is used to couple the pulse detection signal to generate a coupling signal, and based on the coupling signal, it excites the LC resonant circuit to generate an equivalent impedance. Under the action of the equivalent impedance, a detection signal is generated at detection point A. Comparator U1 is used to compare the detection signal with the reference voltage output by the MCU control unit to generate square wave feedback signals with different duty cycles. The MCU control unit is used to determine whether there is a pot on the induction coil of the LC resonant circuit based on different duty cycles of the feedback signal. When it is determined that there is a pot, the MCU control unit controls the relay K1_1 of the corresponding LC resonant circuit to be in the energized state, thereby connecting the first inverter circuit, the second inverter circuit, and the LC resonant circuit, generating a first heating control signal and a second heating control signal, and sending the first heating control signal to the first inverter circuit and the second heating control signal to the second inverter circuit; the first heating control signal and the second heating control signal are complementary square wave signals; The first inverter circuit and the second inverter circuit are used to work alternately under the drive of two sets of complementary square wave signals to generate a high-frequency square wave voltage, and drive the induction coil of the LC resonant circuit to generate an alternating magnetic field based on the high-frequency square wave voltage. The LC resonant circuit is used to form a closed loop with the cookware in an alternating magnetic field to generate eddy currents, and to heat the cookware based on the eddy currents. While any one of the LC resonant circuits is heating the cookware, the other unheated LC resonant circuits are still connected to the MCU control unit through their respective coupling feedback circuits. The MCU control unit continues to detect the cookware without affecting the LC resonant circuits that are already heating the cookware. The step of determining whether there is a pot on the induction coil of the LC resonant circuit based on different duty cycles of the feedback signal includes: reading the duty cycle value of the feedback signal; if the duty cycle value of the feedback signal is greater than a reference duty cycle value, there is a pot on the induction coil of the LC resonant circuit; if the duty cycle value of the feedback signal is less than or equal to the reference duty cycle value, there is no pot on the induction coil of the LC resonant circuit.
2. The cookware detection circuit for the all-area heating induction cooker according to claim 1, characterized in that, Each of the LC resonant circuits is also connected to a first driving circuit and a second driving circuit; the third output terminal OUTA1 of the MCU control unit is connected to the input terminal of the first inverter circuit through the first driving circuit, and the third output terminal OUTB1 of the MCU control unit is connected to the input terminal of the second inverter circuit through the second driving circuit. The MCU control unit outputs a first heating control signal to the first inverter circuit through the first drive circuit; and outputs a second heating control signal to the second inverter circuit through the second drive circuit; the first heating control signal and the second heating control signal are complementary square wave signals; The first inverter circuit and the second inverter circuit are used to work alternately under the drive of two sets of complementary square wave signals to generate high-frequency square wave voltage.
3. The cookware detection circuit for the all-area heating induction cooker according to claim 2, characterized in that, The first drive circuit includes a resistor R3, a driver U2, and a resistor R5; one end of the resistor R5 is connected to the third output terminal OUTA1 of the MCU control unit, the other end of the resistor R5 is connected to the input terminal of the driver U2, the output terminal of the driver U2 is connected to one end of the resistor R3, and the other end of the resistor R3 is connected to the input terminal of the first inverter circuit; the first drive circuit is used to amplify the first heating control signal and output the amplified first heating control signal to the first inverter circuit; The second drive circuit includes a resistor R4, a driver U3, and a resistor R6; one end of the resistor R6 is connected to the third output terminal OUTB1 of the MCU control unit, the other end of the resistor R6 is connected to the input terminal of the driver U3, the output terminal of the driver U3 is connected to one end of the resistor R4, and the other end of the resistor R4 is connected to the input terminal of the second inverter circuit; the second drive circuit is used to amplify the second heating control signal and output the amplified second heating control signal to the second inverter circuit.
4. A method for testing cookware in a full-range heating induction cooker, characterized in that, The method is applied to the cookware detection circuit according to claims 1-3 above, and the method includes: When the induction cooker with full-area heating is powered on, for any set of LC resonant circuits that are not conducting heating, relay K1_1 is in the open state. Capacitors C10_3, C10_4, and C10_5 form a coupling circuit. This coupling feedback circuit is used to receive the pulse detection signal sent by the MCU control unit. The coupling circuit is used to couple the pulse detection signal to generate a coupling signal, and based on the coupling signal, it excites the LC resonant circuit to generate an equivalent impedance. Under the action of the equivalent impedance, a detection signal is generated at detection point A. Comparator U1 is used to compare the detection signal with the reference voltage output by the MCU control unit to generate square wave feedback signals with different duty cycles. The MCU control unit is used to determine whether there is a pot on the induction coil of the LC resonant circuit based on different duty cycles of the feedback signal. When it is determined that there is a pot, the MCU control unit controls the relay K1_1 of the corresponding LC resonant circuit to be in the energized state, thereby connecting the first inverter circuit, the second inverter circuit, and the LC resonant circuit, generating a first heating control signal and a second heating control signal, and sending the first heating control signal to the first inverter circuit and the second heating control signal to the second inverter circuit; the first heating control signal and the second heating control signal are complementary square wave signals; The first inverter circuit and the second inverter circuit are used to work alternately under the drive of two sets of complementary square wave signals to generate a high-frequency square wave voltage, and drive the induction coil of the LC resonant circuit to generate an alternating magnetic field based on the high-frequency square wave voltage. The LC resonant circuit is used to form a closed loop with the cookware in an alternating magnetic field to generate eddy currents, and to heat the cookware based on the eddy currents. While any one of the LC resonant circuits is heating the cookware, the other unheated LC resonant circuits are still connected to the MCU control unit through their respective coupling feedback circuits. The MCU control unit continues to detect the cookware without affecting the LC resonant circuits that are already heating the cookware. The step of determining whether there is a pot on the induction coil of the LC resonant circuit based on different duty cycles of the feedback signal includes: reading the duty cycle value of the feedback signal; if the duty cycle value of the feedback signal is greater than a reference duty cycle value, there is a pot on the induction coil of the LC resonant circuit; if the duty cycle value of the feedback signal is less than or equal to the reference duty cycle value, there is no pot on the induction coil of the LC resonant circuit.
5. A global heating induction cooker, characterized in that, The device includes a control board, which integrates the cookware detection circuit of the full-area heating induction cooker as described in any one of claims 1-3, or the control board is used to execute the cookware detection method of the full-area heating induction cooker as described in claim 4.
Citation Information
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