Electromagnetic heating device, cooking appliance and heating control method

Abstract

The application provides an electromagnetic heating device, a cooking utensil and a heating control method. The electromagnetic heating device comprises a rectification filtering module, a zero-crossing detection module, a driving adjustment module, a power switch tube, a resonant heating module and a control module. The rectification filtering module is used for rectifying and filtering an alternating current power supply and supplying the resonant heating module. The zero-crossing detection module is used for detecting a voltage zero-crossing signal of the alternating current power supply. The driving adjustment module is used for providing a driving voltage to the power switch tube so that the power switch tube controls the resonant heating module to work in resonance. The control module is used for, in a first heating period, judging, according to the voltage zero-crossing signal, whether to output a first driving voltage to drive the power switch tube to work before a voltage zero-crossing point of the alternating current power supply by controlling the driving adjustment module; and in a second heating period, outputting a second driving voltage to drive the power switch tube to work by controlling the driving adjustment module. In this way, electromagnetic noise can be continuous during low-power heating.

Description

Technical Field

[0001] This invention relates to the field of household appliance technology, and in particular to an electromagnetic heating device, a cooking appliance, and a heating control method for the electromagnetic heating device. Background Technology

[0002] An induction cooker is an electric cooking appliance that uses the principle of electromagnetic induction heating. It generates an alternating magnetic field through a high-frequency induction heating coil (i.e., an excitation coil), which induces eddy currents in a metal pot placed on the cooktop, thus heating the food. Induction cookers are widely used due to their advantages such as high efficiency and energy saving, ease of control, and wide applicability.

[0003] In related technologies, induction cookers can achieve low-power heating control by intermittent heating through wave dropping, thereby expanding the low-power range of single-tube topology electromagnetic heating. However, during low-power heating with wave dropping, electromagnetic noise is generated during the heating cycle, while there is no electromagnetic noise during non-heating cycles. This results in discontinuous electromagnetic noise during low-power heating, affecting the user experience of the induction cooker. Summary of the Invention

[0004] The present invention aims to at least partially solve one of the problems in related technologies. To this end, embodiments of the present invention provide an electromagnetic heating device, a cooking appliance, and a heating control method for the electromagnetic heating device.

[0005] The electromagnetic heating device provided in the embodiments of the present invention includes a rectifier and filter module, a zero-crossing detection module, a drive adjustment module, a power switch, a resonant heating module, and a control module;

[0006] The rectifier and filter module is connected to the AC power supply and the resonant heating module, and is used to rectify and filter the AC power supply before supplying it to the resonant heating module.

[0007] The zero-crossing detection module is used to detect the zero-crossing signal of the AC power supply.

[0008] The drive adjustment module is connected to the control electrode of the power switch and is used to provide drive voltage to the control electrode of the power switch.

[0009] The power switch is used to control the resonant heating module to resonate according to the driving voltage;

[0010] The control module is connected to the zero-crossing detection module and the drive adjustment module respectively. The control module is used to: determine, based on the voltage zero-crossing signal, before the voltage zero-crossing point of the AC power supply, by controlling the drive adjustment module to output a first drive voltage so that the power switch operates under the first drive voltage; and during the second heating cycle, control the drive adjustment module to output a second drive voltage so that the power switch operates under the drive of the second drive voltage, wherein the drive voltage includes the first drive voltage and the second drive voltage, and the second drive voltage is greater than the first drive voltage.

[0011] In some implementations, the amplitude of the first driving voltage remains constant, and the pulse width of the first driving voltage increases or remains constant.

[0012] The amplitude of the second driving voltage remains constant, and the pulse width of the second driving voltage increases or remains constant.

[0013] In some embodiments, determining, based on the voltage zero-crossing signal, before the voltage zero-crossing point of the AC power supply, to control the drive adjustment module to output a first drive voltage includes:

[0014] Based on the voltage zero-crossing signal, it is determined that the voltage of the AC power supply is within a preset range from the falling region to the zero-crossing point. By controlling the drive adjustment module to output the first drive voltage, the collector voltage of the power switch tube oscillates and decreases.

[0015] In some embodiments, the pulse width of the first driving voltage is greater than or equal to 0.2 microseconds and less than or equal to 1 / 3 of the pulse width of the second driving voltage.

[0016] In some implementations, the pulse width of the collector voltage of the power switch is in the range of 0.5-10 milliseconds.

[0017] In some embodiments, determining, based on the voltage zero-crossing signal, before the voltage zero-crossing point of the AC power supply, to control the drive adjustment module to output a first drive voltage includes:

[0018] Based on the zero-crossing signal, it is determined that the voltage of the AC power supply is within the zero-crossing range, and the first driving voltage is output by controlling the driving adjustment module.

[0019] In some embodiments, the pulse width of the first driving voltage gradually decreases within the range from the zero-crossing point to the peak point of the AC power supply voltage.

[0020] In some implementations, the pulse width of the first driving voltage is greater than or equal to 0.2 microseconds and less than or equal to the pulse width of the second driving voltage.

[0021] In some implementations, at the zero-crossing point of the AC power supply, the collector voltage of the power switch oscillates to a minimum.

[0022] In some embodiments, the drive adjustment module includes a drive unit and a voltage adjustment unit, wherein the drive unit is connected to the control module and the voltage adjustment unit respectively, and the voltage adjustment unit is connected to the control module and the control electrode of the power switch respectively;

[0023] During the first heating cycle, the control module outputs a first control signal to the drive unit and a second control signal to the voltage regulation unit, so that the power switch tube operates under the drive of a first drive voltage with a constant amplitude.

[0024] During the second heating cycle, the control module outputs the first control signal to the drive unit to make the power switch work under the drive of the second drive voltage, and at the same time outputs the third control signal to the voltage regulation unit to make the voltage regulation unit stop working.

[0025] In some embodiments, the power switch is an IGBT, the first control signal is a PPG pulse, the second control signal is a high-level signal, and the third control signal is a low-level signal.

[0026] The cooking appliance provided in this application includes the electromagnetic heating device.

[0027] The heating control method for the electromagnetic heating device provided in this application includes a resonant heating module, a power switch for controlling the resonant heating module to operate in resonance, a drive adjustment module for driving the power switch, and a zero-crossing detection module. The heating control method includes:

[0028] Upon receiving a low-power heating command, the zero-crossing detection module detects the zero-crossing signal of the AC power supply input to the electromagnetic heating device.

[0029] During the first heating cycle, based on the voltage zero-crossing signal, before the voltage zero-crossing point of the AC power supply, the drive adjustment module is controlled to output a first drive voltage so that the power switch operates at the first drive voltage.

[0030] During the second heating cycle, the drive adjustment module is controlled to output a second drive voltage so that the power switch tube operates under the drive of the second drive voltage, wherein the second drive voltage is greater than the first drive voltage.

[0031] In some implementations, the amplitude of the first driving voltage remains constant, and the pulse width of the first driving voltage increases or remains constant.

[0032] The amplitude of the second driving voltage remains constant, and the pulse width of the second driving voltage increases or remains constant.

[0033] In some embodiments, determining, based on the voltage zero-crossing signal, before the voltage zero-crossing point of the AC power supply, to control the drive adjustment module to output a first drive voltage includes:

[0034] Based on the voltage zero-crossing signal, it is determined that the voltage of the AC power supply is between the falling region and the zero-crossing point. By controlling the drive adjustment module to output the first drive voltage, the collector voltage of the power switch tube oscillates and decreases.

[0035] In some embodiments, the pulse width of the first driving voltage is greater than or equal to 0.2 microseconds and less than or equal to 1 / 3 of the pulse width of the second driving voltage.

[0036] In some implementations, the pulse width of the collector voltage of the power switch is in the range of 0.5-10 milliseconds.

[0037] In some embodiments, determining, based on the voltage zero-crossing signal, before the voltage zero-crossing point of the AC power supply, to control the drive adjustment module to output a first drive voltage includes:

[0038] Based on the zero-crossing signal, it is determined that the voltage of the AC power supply is within the zero-crossing interval period, and the first driving voltage is output by controlling the driving adjustment module.

[0039] In some embodiments, the pulse width of the first driving voltage gradually decreases from the zero-crossing point to the peak of the AC power supply voltage.

[0040] In some implementations, the pulse width of the first driving voltage is greater than or equal to 0.2 microseconds and less than or equal to the pulse width of the second driving voltage.

[0041] In some implementations, at the zero-crossing point of the AC power supply, the collector voltage of the power switch oscillates to a minimum.

[0042] In some embodiments, the drive adjustment module includes a drive unit and a voltage adjustment unit, wherein the drive unit is connected to the control electrode of the power switch transistor, and the voltage adjustment unit is connected to the control electrode of the power switch transistor.

[0043] During the first heating cycle, a first control signal is output to the drive unit, and a second control signal is output to the voltage regulation unit, so that the power switch tube operates under the drive of a first drive voltage with a constant amplitude.

[0044] During the second heating cycle, the first control signal is output to the drive unit to make the power switch work under the drive of the second drive voltage, and at the same time, the third control signal is output to the voltage regulation unit to make the voltage regulation unit stop working.

[0045] In some embodiments, the power switch is an IGBT, the first control signal is a PPG pulse, the second control signal is a high-level signal, and the third control signal is a low-level signal.

[0046] In the electromagnetic heating device, cooking appliance, and heating control method of this application, during the first heating cycle, a lower first driving voltage is output by the control drive adjustment module before the zero-crossing point of the AC power supply, based on the voltage zero-crossing signal. This causes the power switching transistor to operate under the drive of the first driving voltage. During the second heating cycle, a second driving voltage is output by the control drive adjustment module, causing the power switching transistor to operate under the drive of the second driving voltage. This ensures, on the one hand, that the power switching transistor is turned on via a transformer drive when the electromagnetic heating device transitions from the first heating cycle to the second heating cycle, thereby reducing the turn-on current of the power switching transistor and mitigating the damage caused by hard turn-on. On the other hand, since the power switching transistor is also driven by a lower driving voltage during the first heating cycle, continuous electromagnetic noise is ensured during low-power heating, improving the user experience.

[0047] Additional aspects and advantages of the embodiments of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0048] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of embodiments taken in conjunction with the accompanying drawings, wherein:

[0049] Figure 1 This is a schematic diagram of a module of an electromagnetic heating device according to certain embodiments of the present invention;

[0050] Figure 2This is a schematic diagram of another module of the electromagnetic heating device according to certain embodiments of the present invention;

[0051] Figure 3 These are waveform diagrams of the electromagnetic heating device according to certain embodiments of the present invention during low-power heating operation.

[0052] Figure 4 These are waveform diagrams of the electromagnetic heating device according to certain embodiments of the present invention during low-power heating operation.

[0053] Figure 5 This is a schematic flowchart of the heating control method of an electromagnetic heating device according to certain embodiments of the present invention.

[0054] Explanation of icon numbers

[0055] 10-Electromagnetic heating device, 11-Rectifier and filter module, 111-First filter unit, 112-Second filter unit, 113-Rectifier unit, 12-Zero-crossing detection module, 13-Drive adjustment module, 131-Drive unit, 132-Voltage adjustment unit, 14-Power switching transistor, 15-Resonant heating module, L01-Resonant coil, C01-Resonant capacitor, 16-Control module, 17-First current detection module, 18-Voltage detection module, 19-Power supply module, 101-Second current detection module, 20-AC power supply. Detailed Implementation

[0056] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0057] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0058] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows for communication; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0059] Please see Figure 1 This application provides an electromagnetic heating device 10, which may include a rectifier and filter module 11, a zero-crossing detection module 12, a drive adjustment module 13, a power switch 14, a resonant heating module 15, and a control module 16.

[0060] The rectifier and filter module 11 is connected to the AC power supply 20 and the resonant heating module 15, and is used to rectify and filter the AC power supply 20 before supplying it to the resonant heating module 15; the zero-crossing detection module 12 is used to detect the zero-crossing signal of the AC power supply 20; the drive adjustment module 13 is connected to the control electrode of the power switch 14, and is used to provide the drive voltage to the control electrode of the power switch 14; the power switch 14 is used to control the resonant heating module 15 to resonate according to the drive voltage.

[0061] The control module 16 is connected to the zero-crossing detection module 12 and the drive adjustment module 13 respectively. The control module 16 is used to determine, according to the voltage zero-crossing signal, before the voltage zero-crossing point of the AC power supply 20, to control the drive adjustment module 13 to output a first drive voltage so that the power switch 14 can work under the first drive voltage during the first heating cycle; and to control the drive adjustment module 13 to output a second drive voltage during the second heating cycle so that the power switch 14 can work under the drive of the second drive voltage. The drive voltage includes the first drive voltage and the second drive voltage, and the second drive voltage is greater than the first drive voltage.

[0062] In the electromagnetic heating device 10 of this application embodiment, during the first heating cycle, based on the voltage zero-crossing signal, a first driving voltage is output by the control drive adjustment module 13 before the zero-crossing point of the AC power supply 20. This causes the power switch 14 to control the resonant heating module 15 to resonate at a lower power under the drive of the first driving voltage. During the second heating cycle, a second driving voltage is output by the control drive adjustment module 13, causing the power switch 14 to control the resonant heating module 15 to resonate at a higher power under the drive of the second driving voltage. Thus, compared to the related technology's method of intermittent heating using waveform dropping to achieve low-power heating, this ensures continuous electromagnetic noise during low-power heating, improving the user experience. Furthermore, when the electromagnetic heating device 10 transitions from the first heating cycle to the second heating cycle, the power switch 14 is turned on using a transformer drive, thereby reducing the turn-on current of the power switch 14 and mitigating the damage caused by the hard turn-on of the power switch 14.

[0063] Specifically, the electromagnetic heating device 10 can be applied to electric cooking appliances made using the principle of electromagnetic induction heating. The electromagnetic heating device 10 can be applied to an induction cooker. It generates an alternating magnetic field through a high-frequency induction heating coil (i.e., an excitation coil), which causes eddy currents to be generated in the metal pot placed on the electromagnetic heating device 10, thereby heating the food.

[0064] Please see Figure 2The AC power supply 20 can use 220V AC mains power for outputting AC power. One end of the rectifier and filter module 11 is connected to the AC power supply 20, and the other end is connected to the resonant heating module 15. The rectifier and filter module 11 is used to rectify and filter the AC power supply 20 and output DC power to supply the resonant heating module 15. The rectifier and filter module 11 may include a first filter unit 111, a rectifier unit 113, and a second filter unit 112 connected in sequence. The first filter unit 111 is connected to the AC power supply 20 and is used to filter out noise interference in the AC power supply. The rectifier unit 113 can rectify the AC power supply 20 and output DC power to supply the second filter unit 112. The second filter unit 112 is connected to the resonant heating module 15 and is used to filter the DC power and output it to the resonant heating module 15. The zero-crossing detection module 12 is connected to the AC power supply 20 and is used to detect the zero-crossing signal of the AC power supply 20.

[0065] The power switch 14 is connected to the resonant heating module 15 and is used to control the resonant heating module 15 to resonate. The power switch 14 can be driven by the drive adjustment module 13. For example, the drive adjustment module 13 is connected to the control electrode of the power switch 14 and is used to provide different drive voltages to the control electrode of the power switch 14, so that the power switch 14 controls the resonant heating module 15 to resonate under different drive voltages.

[0066] It should be noted that the power switch 14 can have a cutoff state and a conduction amplification state. When the drive voltage output by the drive adjustment module 13 to the power switch 14 is 0, the power switch 14 is in the cutoff state. When the drive voltage output by the drive adjustment module 13 to the power switch 14 is greater than the threshold voltage of the power switch 14, the power switch 14 is in the conduction amplification state. The current of the power switch 14 in the conduction amplification state is positively correlated with the magnitude of the drive voltage of the control electrode. That is, the larger the drive voltage of the control electrode of the power switch 14, the larger the current of the power switch 14, and the greater the output power of the resonant heating module 15.

[0067] In this embodiment, the power switch 14 can be an insulated gate bipolar transistor (IGBT). The collector of the IGBT is connected to the resonant heating module 15, the emitter of the IGBT is connected to the second filter unit 112, and the gate of the IGBT is connected to the drive adjustment module 13.

[0068] The resonant heating module 15 can generate a magnetic field through resonant operation, thereby heating the cookware. The resonant heating module 15 may include a resonant coil L01 and a resonant capacitor C01. The resonant coil L01 is connected to the collectors of the second filter unit 112 and the power switch 14, respectively, and the resonant capacitor C01 is connected in parallel across the resonant coil L01.

[0069] The control module 16 is the core control component of the electromagnetic heating device 10. The control module 16 can be the main control chip and is connected to both the zero-crossing detection module 12 and the drive adjustment module 13. The electromagnetic heating device 10 can receive heating control commands through the control module 16 and respond to these commands by controlling the drive adjustment module 13 to output a drive voltage to the control electrode of the power switch 14. This allows the power switch 14 to control the resonant heating module 15 to resonate under the drive voltage. The heating control commands can be input by the user via buttons.

[0070] Furthermore, the heating control command may include a low-power heating command. Under the low-power heating command, the electromagnetic heating device 10 achieves low-power heating. During the low-power heating process, there may be a first heating cycle and a second heating cycle, which alternate. The duration of the first heating cycle is longer than that of the second heating cycle. For example, the time ratio of the first heating cycle to the second heating cycle may be, but is not limited to, 1 / 1, 2 / 1, 3 / 1, etc. Please refer to [link / reference]. Figure 3 or Figure 4 In this embodiment, the time ratio of the second heating cycle to the first heating cycle can be illustrated by taking 3 / 1 as an example.

[0071] During the first heating cycle, if the control module 16 determines that the voltage of the AC power supply 20 is before the zero-crossing point of the AC power supply 20 based on the zero-crossing signal detected by the zero-crossing detection module 12, it can output a first driving voltage to the control electrode of the power switch 14 through the control drive adjustment module 13, so that the power switch 14 can work at the first driving voltage.

[0072] During the second heating cycle, the control module 16 outputs a second driving voltage to the control electrode of the power switch 14 through the control drive adjustment module 13, so that the power switch 14 operates under the second driving voltage. The second driving voltage is greater than the first driving voltage.

[0073] The drive regulation module 13 can output a first drive voltage or a second drive voltage in a fixed-frequency or variable-frequency manner. The amplitude of the first drive voltage remains constant, while the pulse width of the first drive voltage increases or remains constant. Similarly, the amplitude of the second drive voltage remains constant, while the pulse width of the second drive voltage increases or remains constant. Furthermore, the pulse width of the first drive voltage is smaller than the pulse width of the second drive voltage. In this way, by controlling the pulse widths of the first and second drive voltages to increase or remain constant, the current of the power switch 14 is smoothly controlled, thereby minimizing the inrush current of the power switch 14 and preventing damage to it.

[0074] For example, please see Figure 3 , Figure 3 The waveform diagrams of the electromagnetic heating device 10 during low-power heating operation in some embodiments are as follows, from top to bottom: the waveform of the AC power supply 20, the waveform of the voltage zero-crossing signal, the waveform of the zero-volt detection signal, the waveform of the IGBT driving voltage (including the first driving voltage t1 and the second driving voltage t2), and the waveform of the collector C voltage of the IGBT after being driven by the driving voltage.

[0075] In this embodiment, during the first heating cycle, if the control module 16 determines that the voltage of the AC power supply 20 is within a preset range from the falling region to the zero-crossing point based on the voltage zero-crossing signal, it can control the drive adjustment module 13 to output a first drive voltage t1 to the control electrode of the power switch 14 in a frequency conversion manner, causing the collector voltage T0 of the power switch 14 to oscillate and decrease. During the second heating cycle, the control module 16 controls the drive adjustment module 13 to output a second drive voltage t2 to the control electrode of the power switch 14 in a frequency conversion manner, causing the collector voltage T0 of the power switch 14 to oscillate, increase, and then oscillate and decrease.

[0076] During the first heating cycle, while the voltage of the AC power supply 20 is within a preset range from the falling region to the zero crossing point, the pulse width of the first driving voltage t1 increases incrementally. Furthermore, the pulse width of each first driving voltage t1 is greater than or equal to 0.2 microseconds and less than or equal to 1 / 3 of the pulse width of the second driving voltage t2. For example, the pulse width of the first driving voltage t1 can be 0.2 microseconds, 0.5 microseconds, 0.7 microseconds, 1 microsecond, 2 microseconds, or even longer; the specific value of the pulse width of the first driving voltage t1 is not limited. The pulse width range of the collector voltage T0 of the power switch 14 can be 0.5-10 milliseconds. For example, the pulse width range of the collector voltage T0 can be 0.5 mm, 0.6 mm, 0.8 mm, 1 mm, 2 mm, 5 mm, or 10 mm, etc.

[0077] For example, please see Figure 4 , Figure 4In some embodiments, the electromagnetic heating device 10 is shown as another waveform diagram during low-power heating operation. From top to bottom, the waveforms are: AC power supply 20, zero-crossing voltage signal, zero-volt detection signal, IGBT driving voltage (including first driving voltage t1 and second driving voltage t2), and IGBT resonant voltage waveform (collector voltage waveform) after being driven by the driving voltage.

[0078] In this embodiment, during the first heating cycle, if the control module 16 determines that the voltage of the AC power supply 20 is in the zero-crossing range based on the zero-crossing signal, it controls the drive adjustment module 13 to output the first drive voltage t1 in a frequency conversion manner, causing the collector voltage T1 of the power switch 14 to oscillate and increase before oscillating and decreasing. During the second heating cycle, the control module 16 directly controls the drive adjustment module 13 to output the second drive voltage t2 in a frequency conversion manner, causing the collector voltage T0 of the power switch 14 to oscillate and increase before oscillating and decreasing.

[0079] Furthermore, during the first heating cycle, and within the interval from the zero-crossing point to the peak point of the AC power supply 20, the pulse width of the first driving voltage t1 gradually decreases. Also, within the interval from the peak point to the zero-crossing point of the AC power supply 20, the pulse width of the first driving voltage gradually decreases. Moreover, the pulse width of each first driving voltage t1 is greater than or equal to 0.2 microseconds and less than or equal to the pulse width of the second driving voltage t2. For example, the pulse width of the first driving voltage t1 can be 0.2 microseconds, 0.5 microseconds, 0.7 microseconds, 1 microsecond, 2 microseconds, or even longer; the specific value of the pulse width of the first driving voltage t1 is not limited.

[0080] In some implementations, at the zero-crossing point of the AC power supply 20, the collector voltage of the power switch 14 oscillates to a minimum. Specifically, when the control module 16 determines that the voltage of the AC power supply 20 is at a zero-crossing point based on the zero-crossing signal of the AC power supply 20, the drive adjustment module 13 outputs a drive voltage of 0 to the power switch 14, so that the power switch 14 is in the off state and the collector voltage of the power switch 14 oscillates to a minimum.

[0081] In some embodiments, the drive adjustment module 13 includes a drive unit 131 and a voltage adjustment unit 132. The drive unit 131 is connected to the control electrode of the control module 16 and the power switch 14, respectively, and the voltage adjustment unit 132 is connected to the control electrode of the control module 16 and the power switch 14, respectively.

[0082] In the first heating cycle, the control module 16 outputs a first control signal to the drive unit 131 and a second control signal to the voltage regulation unit 132, so that the power switch 14 operates under the drive of the first drive voltage with a constant amplitude; in the second heating cycle, the control module 16 outputs a first control signal to the drive unit 131 so that the power switch 14 operates under the drive of the second drive voltage, and outputs a third control signal to the voltage regulation unit 132 so that the voltage regulation unit 132 stops operating.

[0083] In this embodiment, the first control signal is a PPG pulse, the second control signal is a high-level signal, and the third control signal is a high-level signal. Specifically, during the first heating cycle, the control module 16 sends a PPG pulse to the drive unit 131 and a high-level signal to the voltage regulation unit 132, thereby outputting a first drive voltage to the power switch 14. At this time, the amplitude of the drive pulse of the power switch 14 is the first drive voltage, and the pulse width is the pulse width of the PPG. The width of the PPG can be set to remain constant or increase regularly. After multiple oscillations, when the voltage reaches the zero-crossing point C, that is, when the collector (C) voltage of the power switch 14 oscillates to its minimum, the first heating cycle ends, and the second heating cycle begins. The control module 16 sends a PPG pulse to the drive unit 131 and a low-level signal to the voltage regulation unit 132, thereby outputting a second drive voltage to the power switch 14. The drive voltage of the power switch 14 changes to the second drive voltage, and the power switch 14 is in a normal switching state. Thereafter, the drive voltage of the power switch 14 is maintained at the second drive voltage, and its pulse width remains constant or increases or decreases regularly. At the next zero-crossing point, the drive of the power switch 14 is turned off. This ensures continuous heating of the electromagnetic heating device 10 during low-power heating and reduces electromagnetic noise during the heating process.

[0084] Please see Figure 2 In some embodiments, the electromagnetic heating device 10 may further include a first current detection module 17, a voltage detection module 18, a power supply module 19, and a second current detection module 101. The first current detection module 17 is connected to the rectifier unit 113 and is used to detect the magnitude of the DC current and provide it to the control module 16. The second current detection module 101 is connected to the emitter of the power switch 14 and is used to detect the current of the power switch 14 and provide it to the control module 16. The voltage detection module 18 is connected to the AC power supply 20 and the control module 16 and is used to detect the voltage of the AC power supply 20. The power supply module 19 is connected to the AC power supply 20 and the control module 16 and is used to supply power to the control module 16 according to the AC power supply 20.

[0085] Please see Figure 5This application also provides a heating control method for an electromagnetic heating device 10. The electromagnetic heating device 10 includes a resonant heating module, a power switch for controlling the resonant heating module to operate in resonance, a drive adjustment module 13 for driving the power switch, and a zero-crossing detection module. The heating control method includes:

[0086] 01. Upon receiving a low-power heating command, the zero-crossing signal of the AC power supply input to the electromagnetic heating device is detected by the zero-crossing detection module.

[0087] 02. During the first heating cycle, based on the voltage zero-crossing signal, the first driving voltage is output by the control drive adjustment module before the voltage zero-crossing point of the AC power supply, so that the power switching tube operates at the first driving voltage.

[0088] 03. During the second heating cycle, the second driving voltage is output by the control drive adjustment module so that the power switching tube works under the drive of the second driving voltage, wherein the second driving voltage is greater than the first driving voltage.

[0089] In the heating control method of the electromagnetic heating device in this application embodiment, when a low-power heating command is received, the zero-crossing detection module detects the zero-crossing signal of the AC power supply input to the electromagnetic heating device. This allows the control drive adjustment module to output a first driving voltage before the zero-crossing point of the AC power supply during the first heating cycle, based on the zero-crossing signal. This enables the power switch to control the resonant heating module to operate at a lower power under the drive of the first driving voltage. During the second heating cycle, the control drive adjustment module outputs a second driving voltage, enabling the power switch to control the resonant heating module to operate at a higher power under the drive of the second driving voltage. Thus, compared to the intermittent heating method using waveform dropping in related technologies to achieve low-power heating, this method ensures continuous electromagnetic noise during low-power heating, improving the user experience. Furthermore, by using a transformer drive to turn on the power switch when the electromagnetic heating device transitions from the first heating cycle to the second heating cycle, the turn-on current of the power switch is reduced, mitigating the damage caused by hard turn-on of the power switch. This avoids excessive overheating of the power switching tube, improves the operational reliability of cooking appliances, and expands the heating power range of cooking appliances.

[0090] Specifically, during the first heating cycle, the drive adjustment module can be controlled to output a first drive voltage at a fixed or variable frequency. The amplitude of the first drive voltage remains constant, while the pulse width of the first drive voltage increases or remains constant. During the second heating cycle, the drive adjustment module can be controlled to output a second drive voltage at a fixed or variable frequency. The amplitude of the second drive voltage remains constant, while the pulse width of the second drive voltage increases or remains constant. Furthermore, the pulse width of the first drive voltage is shorter than the pulse width of the second drive voltage. Thus, by controlling the pulse widths of the first and second drive voltages to increase or remain constant, the current of the power switch can be smoothly controlled, thereby minimizing the inrush current of the power switch and preventing damage to the power switch.

[0091] In some implementations, 02 includes:

[0092] 021. Based on the voltage zero-crossing signal, it is determined that the AC power supply voltage is in the falling region to the zero-crossing point. The first driving voltage is output by controlling the drive adjustment module, so that the collector voltage of the power switch tube oscillates and decreases.

[0093] In this embodiment, the drive adjustment module can be controlled to output a first drive voltage t1 in a frequency conversion manner, causing the collector voltage T0 of the power switch to oscillate and decrease. The pulse width of the first drive voltage t1 increases incrementally, and the pulse width of each first drive voltage t1 is greater than or equal to 0.2 microseconds and less than or equal to 1 / 3 of the pulse width of the second drive voltage t2. For example, the pulse width of the first drive voltage t1 can be 0.2 microseconds, 0.5 microseconds, 0.7 microseconds, 1 microsecond, 2 microseconds, or even longer; the specific value of the pulse width of the first drive voltage t1 is not limited. The pulse width range of the collector voltage T0 of the power switch can be 0.5-10 millimeters. For example, the pulse width range of the collector voltage T0 can be 0.5 mm, 0.6 mm, 0.8 mm, 1 mm, 2 mm, 5 mm, or 10 mm, etc.

[0094] In some implementations, 02 includes:

[0095] 022. Based on the voltage zero-crossing signal, it is determined that the AC power supply voltage is within the zero-crossing interval period, and the first driving voltage is output by controlling the drive adjustment module.

[0096] In this embodiment, during the first heating cycle, and within the interval from the zero-crossing point to the peak point of the AC power supply voltage, the pulse width of the first driving voltage t1 gradually decreases. Furthermore, within the interval from the peak point to the zero-crossing point of the AC power supply voltage, the pulse width of the first driving voltage gradually decreases. Each pulse width of the first driving voltage t1 is greater than or equal to 0.2 microseconds and less than or equal to the pulse width of the second driving voltage t2. For example, the pulse width of the first driving voltage t1 can be 0.2 microseconds, 0.5 microseconds, 0.7 microseconds, 1 microsecond, 2 microseconds, or even longer; the specific value of the pulse width of the first driving voltage t1 is not limited.

[0097] In some implementations, the drive regulation module includes a drive unit and a voltage regulation unit, with the drive unit connected to the voltage regulation unit and the voltage regulation unit connected to the control electrode of the power switching transistor.

[0098] Step 02 also includes:

[0099] 023, in the first heating cycle, a first control signal is output to the drive unit, and a second control signal is output to the voltage regulation unit, so that the power switching tube operates under the drive of the first drive voltage with a constant amplitude;

[0100] Step 03 also includes:

[0101] 031. In the second heating cycle, the control module outputs a first control signal to the drive unit to make the power switching tube work under the drive of the second drive voltage, and at the same time outputs a third control signal to the voltage regulation unit to make the voltage regulation unit stop working.

[0102] In this embodiment, the power switch is an IGBT, the first control signal is a PPG pulse, the second control signal is a high-level signal, and the third control signal is a low-level signal. Specifically, during the first heating cycle, a PPG pulse is sent to the drive unit, and a high-level signal is sent to the voltage regulation unit, thereby outputting a first drive voltage to the power switch. At this time, the amplitude of the drive pulse of the power switch is the first drive voltage, and the pulse width is the pulse width of the PPG. The width of the PPG can be set to remain constant or increase regularly. After multiple oscillations, when the voltage reaches the zero-crossing point C, that is, when the collector (C) voltage of the power switch oscillates to its minimum, the first heating cycle ends, and the second heating cycle begins. A PPG pulse is sent to the drive unit, and a low-level signal is sent to the voltage regulation unit, thereby outputting a second drive voltage to the power switch. The drive voltage of the power switch changes to the second drive voltage, and the power switch is in a normal switching state. Thereafter, the drive voltage of the power switch is maintained at the second drive voltage, and its pulse width remains constant or increases and decreases regularly. At the next zero-crossing point, the drive of the power switch is turned off. This ensures continuous heating during low-power heating and reduces electromagnetic noise during the heating process.

[0103] In some implementations, the collector voltage of the power switch oscillates to a minimum at the zero-crossing point of the AC power supply. Specifically, when it is determined from the zero-crossing signal of the AC power supply that the AC power supply voltage is at a zero-crossing point, the drive adjustment module outputs a drive voltage of 0 to the power switch, causing the power switch to be in the off state so that the collector voltage of the power switch oscillates to a minimum.

[0104] This application also provides a cooking appliance, which may include the electromagnetic heating device of any of the above embodiments.

[0105] In the cooking appliance of this application embodiment, during the first heating cycle, a first driving voltage is output by the control drive adjustment module before the zero-crossing point of the AC power supply, based on the voltage zero-crossing signal. This causes the power switch to control the resonant heating module to resonate at a lower power under the drive of the first driving voltage. During the second heating cycle, a second driving voltage is output by the control drive adjustment module, causing the power switch to control the resonant heating module to resonate at a higher power under the drive of the second driving voltage. Thus, compared to related technologies that use wave dropping for intermittent heating to achieve low-power heating, this ensures continuous electromagnetic noise during low-power heating, improving the user experience. Furthermore, by using a transformer drive to turn on the power switch when the electromagnetic heating device transitions from the first heating cycle to the second heating cycle, the turn-on current of the power switch is reduced, minimizing damage caused by hard turn-on. This avoids severe overheating of the power switch, improves the operational reliability of the cooking appliance, and broadens its heating power range.

[0106] Cooking appliances can be electric cooking appliances made using the principle of electromagnetic induction heating, such as induction cookers, induction pressure cookers, or induction rice cookers.

[0107] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0108] 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 this patent application. 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. An electromagnetic heating device, characterized in that, The electromagnetic heating device includes a rectifier and filter module, a zero-crossing detection module, a drive adjustment module, a power switch, a resonant heating module, and a control module. The rectifier and filter module is connected to the AC power supply and the resonant heating module, and is used to rectify and filter the AC power supply before supplying it to the resonant heating module. The zero-crossing detection module is used to detect the zero-crossing signal of the AC power supply. The drive adjustment module is connected to the control electrode of the power switch and is used to provide drive voltage to the control electrode of the power switch. The power switch is used to control the resonant heating module to resonate according to the driving voltage; The control module is connected to the zero-crossing detection module and the drive adjustment module respectively. The control module is used to: determine, according to the voltage zero-crossing signal, before the voltage zero-crossing point of the AC power supply, control the drive adjustment module to output a first drive voltage so that the power switch works at the first drive voltage. During the second heating cycle, the drive adjustment module outputs a second drive voltage to enable the power switch to operate under the drive of the second drive voltage. The drive voltage includes the first drive voltage and the second drive voltage, and the second drive voltage is greater than the first drive voltage.

2. The electromagnetic heating device according to claim 1, characterized in that, The amplitude of the first driving voltage remains constant, and the pulse width of the first driving voltage increases or remains constant. The amplitude of the second driving voltage remains constant, and the pulse width of the second driving voltage increases or remains constant.

3. The electromagnetic heating device according to claim 2, characterized in that, During the first heating cycle, based on the voltage zero-crossing signal, before the voltage zero-crossing point of the AC power supply, the drive adjustment module is controlled to output a first drive voltage, including: Based on the voltage zero-crossing signal, it is determined that the voltage of the AC power supply is within a preset range from the falling region to the zero-crossing point. By controlling the drive adjustment module to output the first drive voltage, the collector voltage of the power switch tube oscillates and decreases.

4. The electromagnetic heating device according to claim 3, characterized in that, The pulse width of the first driving voltage is greater than or equal to 0.2 microseconds and less than or equal to 1 / 3 of the pulse width of the second driving voltage.

5. The electromagnetic heating device according to claim 4, characterized in that, Based on the voltage zero-crossing signal, the voltage of the AC power supply is determined to be within a preset range from the falling region to the zero-crossing point, and the pulse width range of the collector voltage of the power switch is 0.5-10 milliseconds.

6. The electromagnetic heating device according to claim 2, characterized in that, During the first heating cycle, based on the voltage zero-crossing signal, before the voltage zero-crossing point of the AC power supply, the drive adjustment module is controlled to output a first drive voltage, including: Based on the zero-crossing signal, it is determined that the voltage of the AC power supply is within the zero-crossing range, and the first driving voltage is output by controlling the driving adjustment module.

7. The electromagnetic heating device according to claim 6, characterized in that, Within the range of the AC power supply voltage from the zero-crossing point to the peak point of the AC power supply, the pulse width of the first driving voltage gradually decreases.

8. The electromagnetic heating device according to claim 7, characterized in that, The pulse width of the first driving voltage is greater than or equal to 0.2 microseconds and less than or equal to the pulse width of the second driving voltage.

9. The electromagnetic heating device according to any one of claims 1-8, characterized in that, At the zero-crossing point of the AC power supply, the collector voltage of the power switch oscillates to a minimum.

10. The electromagnetic heating device according to claim 1, characterized in that, The drive adjustment module includes a drive unit and a voltage adjustment unit. The drive unit is connected to the control module and the voltage adjustment unit, respectively. The voltage adjustment unit is connected to the control module and the control electrode of the power switch. During the first heating cycle, the control module outputs a first control signal to the drive unit and a second control signal to the voltage regulation unit, so that the power switch tube operates under the drive of a first drive voltage with a constant amplitude. During the second heating cycle, the control module outputs the first control signal to the drive unit to make the power switch work under the drive of the second drive voltage, and at the same time outputs the third control signal to the voltage regulation unit to make the voltage regulation unit stop working.

11. The electromagnetic heating device according to claim 10, characterized in that, The power switch is an IGBT, the first control signal is a PPG pulse, the second control signal is a high-level signal, and the third control signal is a low-level signal.

12. A cooking utensil, characterized in that, Includes the electromagnetic heating device according to any one of claims 1-11.

13. A heating control method for an electromagnetic heating device, characterized in that, The electromagnetic heating device includes a resonant heating module, a power switch for controlling the resonant heating module to resonate, a drive adjustment module for driving the power switch, and a zero-crossing detection module. The heating control method includes: Upon receiving a low-power heating command, the zero-crossing detection module detects the zero-crossing signal of the AC power supply input to the electromagnetic heating device. During the first heating cycle, based on the voltage zero-crossing signal, before the voltage zero-crossing point of the AC power supply, the drive adjustment module is controlled to output a first drive voltage so that the power switch operates at the first drive voltage. During the second heating cycle, the drive adjustment module is controlled to output a second drive voltage so that the power switch tube operates under the drive of the second drive voltage, wherein the second drive voltage is greater than the first drive voltage.

14. The heating control method according to claim 13, characterized in that, The amplitude of the first driving voltage remains constant, and the pulse width of the first driving voltage increases or remains constant. The amplitude of the second driving voltage remains constant, and the pulse width of the second driving voltage increases or remains constant.

15. The heating control method according to claim 14, characterized in that, Based on the voltage zero-crossing signal, before the voltage zero-crossing point of the AC power supply, the drive adjustment module is controlled to output a first drive voltage, including: Based on the voltage zero-crossing signal, it is determined that the voltage of the AC power supply is between the falling region and the zero-crossing point. By controlling the drive adjustment module to output the first drive voltage, the collector voltage of the power switch tube oscillates and decreases.

16. The heating control method according to claim 15, characterized in that, The pulse width of the first driving voltage is greater than or equal to 0.2 microseconds and less than or equal to 1 / 3 of the pulse width of the second driving voltage.

17. The heating control method according to claim 16, characterized in that, The pulse width of the collector voltage of the power switch is in the range of 0.5-10 milliseconds.

18. The heating control method according to claim 15, characterized in that, Based on the voltage zero-crossing signal, before the voltage zero-crossing point of the AC power supply, the drive adjustment module is controlled to output a first drive voltage, including: Based on the zero-crossing signal, it is determined that the voltage of the AC power supply is within the zero-crossing interval period, and the first driving voltage is output by controlling the driving adjustment module.

19. The heating control method according to claim 18, characterized in that, During the period from the zero-crossing point to the peak of the AC power supply, the pulse width of the first driving voltage gradually decreases.

20. The heating control method according to claim 19, characterized in that, The pulse width of the first driving voltage is greater than or equal to 0.2 microseconds and less than or equal to the pulse width of the second driving voltage.

21. The heating control method according to any one of claims 13-20, characterized in that, At the zero-crossing point of the AC power supply, the collector voltage of the power switch oscillates to a minimum.

22. The heating control method according to claim 13, characterized in that, The drive adjustment module includes a drive unit and a voltage adjustment unit. The drive unit is connected to the control electrode of the power switch, and the voltage adjustment unit is connected to the control electrode of the power switch. During the first heating cycle, a first control signal is output to the drive unit, and a second control signal is output to the voltage regulation unit, so that the power switch tube operates under the drive of a first drive voltage with a constant amplitude. During the second heating cycle, the first control signal is output to the drive unit to make the power switch work under the drive of the second drive voltage, and at the same time, the third control signal is output to the voltage regulation unit to make the voltage regulation unit stop working.

23. The heating control method according to claim 22, characterized in that, The power switch is an IGBT, the first control signal is a PPG pulse, the second control signal is a high-level signal, and the third control signal is a low-level signal.

Images