Electromagnetic heating device and cooking appliance

Abstract

The application provides an electromagnetic heating device and a cooking appliance. The electromagnetic heating device comprises a plurality of resonant heating circuits and a control chip. The resonant heating circuit comprises a heating module, a power switch tube, a driving module and a synchronization detection module. The driving module is used for driving the power switch tube to turn on and turn off, so that the power switch tube controls the heating module to work. The synchronization detection module is used for detecting a synchronization signal of the resonant heating circuit. The control chip comprises a driving port, a switch port and a synchronization detection port. Each driving port is connected with the driving module of at least two resonant heating circuits. The switch port is connected with the driving module and the synchronization detection module. Each synchronization detection port is connected with the synchronization detection module of at least two resonant heating circuits. The synchronization detection module detects the synchronization signal and provides the detection module with the synchronization signal when the switch port outputs a low-level signal. The driving module drives the power switch tube to turn on when the switch port outputs a low-level signal and the driving port outputs a driving signal.

Description

Technical Field

[0001] This invention relates to the field of household appliance technology, and in particular to an electromagnetic heating device and a cooking utensil. 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] Multi-coil induction cooktops require numerous I / O ports if a single chip is used to simultaneously drive and control the multi-coil resonant heating circuit. In particular, the PPG drive port for the resonant heating circuit needs an independent timer, and the hardware drive functions associated with synchronization signals and PPG outputs are also required. Chips typically have limited PPG output ports. Using high-specification chips is costly, while using conventional chips results in insufficient drive ports. Furthermore, using two or more single-chip systems to simultaneously drive and control the multi-coil resonant heating circuit, without achieving synchronized frequency control, can lead to asynchronous magnetic fields between the coils, mutual interference, or the generation of sharp noise. Summary of the Invention

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

[0005] The electromagnetic heating device provided by the embodiments of the present invention includes a filter and rectifier circuit, multiple resonant heating circuits and a control chip. The filter and rectifier circuit is connected to an AC power supply and each of the resonant heating circuits, and is used to rectify and filter the AC power supply before inputting it to the resonant heating circuit.

[0006] Each of the resonant heating circuits includes a heating module, a power switch, a driving module, and a synchronization detection module. The heating module is connected to the filter and rectifier circuit and the power switch. The driving module is connected to the control electrode of the power switch and is used to drive the power switch to turn on and off to control the heating module to resonate. The synchronization detection module is connected to the rectifier and filter circuit and the power switch and is used to detect the synchronization signal of the resonant heating circuit.

[0007] The control chip includes a drive port, a switch port, and a synchronization detection port. The drive port can output a pulse signal, which includes a drive signal. The switch port can output a low-level signal and a high-level signal. Each drive port is connected to at least two drive modules of the resonant heating circuit. The switch port is connected to the drive module and the synchronization detection module. Each synchronization detection port is connected to at least two synchronization detection modules of the resonant heating circuit.

[0008] The synchronization detection module detects the synchronization signal and provides it to the detection module when the switch port outputs a low-level signal, and stops detecting the synchronization signal when the switch port outputs a high-level signal;

[0009] The driving module drives the power switch to conduct when the switch port outputs a low-level signal and the driving port outputs a driving signal.

[0010] In some embodiments, the driving module includes:

[0011] The drive unit is connected to the drive port;

[0012] A drive switch unit is connected to the drive unit and the switch port. When a low-level signal is received from the switch port, the drive unit controls the drive unit to connect to the control electrode of the power switch. When the drive unit is connected to the control electrode of the power switch, if a drive signal is received from the drive port, the drive unit controls the power switch to turn on.

[0013] In some embodiments, the drive switching unit includes a semiconductor switching device.

[0014] In some implementations, the synchronization detection module includes:

[0015] The signal detection unit is connected to the rectifier filter circuit, the power switch, and the synchronization detection port, respectively.

[0016] The selection unit, connected to the switch port and the signal detection unit, is used to control the signal detection unit to detect the synchronization signal of the resonant heating circuit and output it to the synchronization detection port when a low-level signal is received from the switch port.

[0017] In some embodiments, the signal detection unit includes a first detection terminal and a second detection terminal. The first detection terminal is connected to the rectifier filter circuit and is used to detect the relative static voltage of the heating module. The second detection terminal is connected to the power switch and is used to detect the dynamic voltage of the heating module.

[0018] In some embodiments, the selection unit is connected to the first detection terminal, and the selection unit is used to connect the first detection terminal to the rectifier filter circuit when a low-level signal is received from the switch port, and to disconnect the first detection terminal from the rectifier filter circuit when a high-level signal is received from the switch port.

[0019] In some implementations, the selection unit includes a semiconductor switching device.

[0020] In some embodiments, the control chip further includes a voltage protection port, and the resonant heating circuit further includes a voltage protection detection module. The voltage protection detection module is connected to the voltage protection port and can detect the resonant voltage of the heating module and generate an adjustment signal based on the resonant voltage, so that the control chip adjusts the pulse width of the drive signal according to the adjustment signal.

[0021] In some embodiments, the voltage protection detection module includes:

[0022] The first voltage protection unit, connected to the power switch and the voltage protection port, is used to generate a first adjustment signal when the resonant voltage of the heating module is detected to be greater than a first voltage threshold, so that the control chip adjusts the pulse width of the drive signal according to the adjustment signal.

[0023] The second voltage protection unit is connected to the power switch and the voltage protection port. It is used to generate a second adjustment signal when the resonant voltage of the heating module is detected to be greater than the second voltage threshold, so that the control chip stops outputting the drive signal according to the second adjustment signal. The second voltage threshold is greater than the first voltage threshold.

[0024] In some embodiments, the voltage protection detection module is connected to the second detection terminal to detect the resonant voltage of the heating module through the second detection terminal.

[0025] In some implementations, the control chip is used for:

[0026] When the synchronization detection port receives a synchronization signal from any of the resonant heating circuits, the pulse signal is generated based on the synchronization signal and output through the drive port.

[0027] The cooking appliance provided in this application includes the electromagnetic heating device described above.

[0028] In the electromagnetic heating device, cooking appliance, and heating control method of this application, a control chip connects the drive port to the drive modules of at least two resonant heating circuits, connects the switch port to the drive module and the synchronization detection module, and connects the synchronization detection port to the synchronization detection modules of at least two resonant heating circuits. This achieves multiplexing of the drive port, switch port, and synchronization detection port, enabling the control chip to control the drive modules of multiple resonant heating circuits through one drive port and multiple switch ports, thereby achieving heating control of multiple resonant heating circuits. Simultaneously, the switch port can also be used to detect and control the synchronization signal in the resonant heating circuit. Thus, a single control chip can achieve drive control of multiple resonant heating circuits. On the one hand, it can achieve synchronous frequency control of multiple resonant heating circuits, avoiding mutual interference of magnetic fields between resonant heating circuits and reducing the noise of the electromagnetic heating device. On the other hand, it reduces the material cost of the electromagnetic heating device.

[0029] 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

[0030] 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:

[0031] Figure 1 This is a schematic diagram of a module of an electromagnetic heating device according to certain embodiments of the present invention;

[0032] Figure 2 This is a schematic diagram of the circuit module of an electromagnetic heating device according to certain embodiments of the present invention;

[0033] Figure 3 This is a circuit diagram of a driving module according to certain embodiments of the present invention;

[0034] Figure 4 This is a circuit diagram of a synchronization detection module according to certain embodiments of the present invention;

[0035] Figure 5 This is a circuit diagram of a voltage protection detection module according to certain embodiments of the present invention.

[0036] Explanation of icon numbers

[0037] 100-Electromagnetic heating device, 10-Rectifier and filter circuit, 11-First filter unit, 12-Second filter unit, 13-Rectifier unit, 20-Resonant heating circuit, 21-Heating module, 22-Power switch tube, 23-Drive module, 231-Drive unit, 232-Drive switch unit, 24-Synchronization detection module, 241-Signal detection unit, 242-Selection unit, 25-Voltage protection detection module, 251-First voltage protection unit, 252-Second voltage protection unit, 30-Control chip, PPG-Drive port, SW-Switch port, SYNC-Synchronization detection port, INT-Voltage protection port, 200-AC power supply. Detailed Implementation

[0038] 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.

[0039] 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.

[0040] 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.

[0041] Please see Figure 1 and Figure 2 The present invention provides an electromagnetic heating device 100, which includes a filter and rectifier circuit, multiple resonant heating circuits 20 and a control chip 30. The filter and rectifier circuit is connected to an AC power supply 200 and each resonant heating circuit 20, and is used to rectify and filter the AC power supply 200 before inputting it to the resonant heating circuit 20.

[0042] Each resonant heating circuit 20 includes a heating module 21, a power switch 22, a drive module 23, and a synchronization detection module 24. The heating module 21 is connected to a filter and rectifier circuit and the power switch 22. The drive module 23 is connected to the control electrode of the power switch 22 and is used to drive the power switch 22 to turn on and off to control the heating module 21 to resonate. The synchronization detection module 24 is connected to the rectifier and filter circuit 10 and the power switch 22 and is used to detect the synchronization signal of the resonant heating circuit 20.

[0043] The control chip 30 includes a drive port PPG, a switch port SW, and a synchronization detection port SYNC. The drive port PPG can output pulse signals, including drive signals. The switch port SW can output low-level signals and high-level signals. Each drive port PPG is connected to at least two drive modules 23 of the resonant heating circuit 20. The switch port SW is connected to the drive module 23 and the synchronization detection module 24. Each synchronization detection port SYNC is connected to at least two synchronization detection modules 24 of the resonant heating circuit 20.

[0044] The synchronization detection module 24 detects the synchronization signal and provides it to the detection module when the switch port SW outputs a low-level signal, and stops detecting the synchronization signal when the switch port SW outputs a high-level signal; the drive module 23 drives the power switch 22 to conduct when the switch port SW outputs a low-level signal and the drive port PPG outputs a drive signal.

[0045] In the electromagnetic heating device 100 of this application embodiment, the control chip 30 connects the drive port PPG to the drive modules 23 of at least two resonant heating circuits 20, connects the switch port SW to the drive modules 23 and the synchronization detection module 24, and connects the synchronization detection port SYNC to the synchronization detection modules 24 of at least two resonant heating circuits 20. This allows the control chip 30 to control the drive modules 23 of multiple resonant heating circuits 20 through one drive port PPG and multiple switch ports SW, thereby achieving heating control of multiple resonant heating circuits 20. At the same time, the switch port SW can also be used to detect and control the synchronization signal in the resonant heating circuits 20. Thus, a single control chip 30 can achieve drive control of multiple resonant heating circuits 20. On the one hand, it can achieve synchronous frequency control of multiple resonant heating circuits 20, avoiding mutual interference of magnetic fields between resonant heating circuits 20 and reducing the noise of the electromagnetic heating device 100. On the other hand, it reduces the material cost of the electromagnetic heating device 100.

[0046] Specifically, the electromagnetic heating device 100 can be applied to electric cooking appliances made using the principle of electromagnetic induction heating. The electromagnetic heating device 100 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 100, thereby heating the food.

[0047] Please see Figure 1 and Figure 2 The electromagnetic heating device 100 includes a rectifier filter circuit 10, a resonant heating circuit 20, and a control chip 30.

[0048] The electromagnetic heating device 100 is connected to an AC power supply 200 via a rectifier and filter circuit 10. The rectifier and filter circuit 10 rectifies and filters the AC power supply 200 and outputs DC power to supply the resonant heating circuit 20, thereby powering the resonant heating circuit 20. The AC power supply 200 can be a 220V AC mains power supply. The rectifier and filter circuit 10 may include a first filter unit 11, a rectifier unit 13, and a second filter unit 12 connected in sequence. The first filter unit 11 is connected to the AC power supply 200 and is used to filter out noise interference in the AC power supply 200. The rectifier unit 13 rectifies the AC power supply 200 and outputs DC power to the second filter unit 12. The second filter unit 12 is connected to the resonant heating circuit 20 and is used to filter the DC power before outputting it to the resonant heating circuit 20.

[0049] The electromagnetic heating device 100 achieves its heating function through resonant heating circuits 20. Multiple resonant heating circuits 20 are included; for example, there may be 2, 3, 4, 5, 6, or even more resonant heating circuits 20. That is, the specific number of resonant heating circuits 20 is unlimited. All resonant heating circuits 20 are connected to a control chip 30, which is used to drive and control the multiple resonant heating circuits 20.

[0050] Each resonant heating circuit 20 may include a heating module 21, a power switch 22, a drive module 23, and a synchronization detection module 24. The heating module 21 is connected to the second filter unit 12 of the rectifier circuit and the collector of the power switch 22, respectively. The rectifier circuit 10 supplies power to the heating module 21. The heating module 21 can resonate to generate a magnetic field, thereby heating the cookware. The heating module 21 may include a resonant capacitor L1 and a resonant capacitor C1. The resonant capacitor L1 is connected to the second filter unit 12 and the collector of the power switch 22, respectively, and the resonant capacitor C1 is connected in parallel across the resonant capacitor L1.

[0051] The power switch 22 is used to control the heating module 21 to perform resonant heating. The drive module 23 is connected to the control electrode of the power switch 22 and is used to output a drive voltage to the power switch 22 to drive it to turn on and off, thereby controlling the heating module 21 to perform resonant heating. The power switch 22 can be an Insulated Gate Bipolar Transistor (IGBT). The power switch 22 can have an off state and a conduction amplification state. When the drive voltage output by the drive module 23 to the power switch 22 is 0, the power switch 22 is in the off state. When the drive voltage output by the drive module 23 to the power switch 22 is greater than the threshold voltage of the power switch 22, the power switch 22 is in the conduction amplification state. The current of the power switch 22 in the conduction amplification state is positively correlated with the magnitude of the drive voltage at the control electrode. That is, the larger the drive voltage at the control electrode of the power switch 22, the larger the current of the power switch 22, and the greater the output power of the heating module 21.

[0052] The synchronization detection module 24 is connected to the collectors of the rectifier filter circuit 10 and the power switch 22 respectively, and is used to detect the synchronization signal of the resonant heating circuit 20.

[0053] The control chip 30 may include multiple sets of ports, each set including a drive port PPG, one or more switch ports SW, and a synchronization detection port SYNC. The control chip 30 can output pulse signals through the drive port PPG, which may include drive signals and invalid signals; for example, a low pulse signal indicates a drive signal, and a high pulse signal indicates an invalid signal. It can also output low-level or high-level signals through the switch ports SW and receive synchronization signals from the resonant heating circuit 20 through the synchronization detection port SYNC. In each set of ports, the drive port PPG can connect to at least two drive modules 23 of the resonant heating circuit 20, each switch port SW connects one drive module 23 and one synchronization detection module 24 in the resonant heating circuit 20, and each synchronization detection port SYNC can connect to at least two synchronization detection modules 24 in the resonant heating circuit 20. Thus, the control chip 30 can implement drive control of one or more resonant heating circuits 20 through each set of ports.

[0054] The control chip 30 can drive the resonant heating circuit 20 through each group of ports in the following ways:

[0055] When the pulse signal output by the control chip 30 through the drive port PPG is the drive signal, and the low-level signal is output through the switch port SW, the synchronization detection module 24 can detect the synchronization signal of the resonant heating circuit 20 according to the low-level signal and provide it to the control chip 30. The drive module 23 drives the power switch 22 to conduct according to the drive signal and the low-level signal.

[0056] When the control chip 30 outputs a pulse signal through the drive port PPG as a drive signal and outputs a high-level signal through the switch port SW, the synchronization detection module 24 can stop detecting the synchronization signal of the resonant heating circuit 20 according to the high-level signal, and the drive module 23 drives the power switch 22 to turn off according to the invalid signal and the low-level signal.

[0057] When the pulse signal output by the control chip 30 through the drive port PPG is invalid and a low-level signal is output through the switch port SW, the synchronization detection module 24 can detect the synchronization signal of the resonant heating circuit 20 according to the low-level signal and provide it to the control chip 30. The drive module 23 drives the power switch 22 to turn off according to the invalid signal and the low-level signal.

[0058] When the pulse signal output by the control chip 30 through the drive port PPG is invalid and a high-level signal is output through the switch port SW, the synchronization detection module 24 can stop detecting the synchronization signal of the resonant heating circuit 20 according to the high-level signal, and the drive module 23 drives the power switch 22 to turn off according to the invalid signal and the high-level signal.

[0059] Thus, a single control chip 30 can be used to drive and control multiple resonant heating circuits 20. On the one hand, it can achieve synchronous frequency control of multiple resonant heating circuits 20, avoiding mutual interference of magnetic fields between resonant heating circuits 20 and reducing the noise of electromagnetic heating device 100. On the other hand, it reduces the material cost of electromagnetic heating device 100.

[0060] For example, in some examples, the control chip 30 includes a drive port PPG1, a switch port SW1 and a switch port SW2, and a synchronization detection port SYNC1. The resonant heating circuit 1 includes a heating module 1, a power switch 1, a drive module 1, and a synchronization detection module 1. The resonant heating circuit 2 includes a heating module 2, a power switch 2, a drive module 2, and a synchronization detection module 2. Specifically, the drive port PPG1 connects to drive module 1 and drive module 2, the switch port SW1 connects to synchronization detection module 1, the switch port SW2 connects to synchronization detection module 2, and the synchronization detection port SYNC1 connects to synchronization detection module 1 and synchronization detection module 2.

[0061] When the drive port PPG1 outputs a pulse signal, and the switch port SW1 and switch port SW2 both output a low-level signal, the drive module 1 drives the power switch transistor 1 to control the heating module 1, and the drive module 1 drives the power switch transistor 2 to control the heating module 2. The synchronization detection module 1 detects the synchronization signal of the resonant heating circuit 1, and the synchronization detection module 2 detects the synchronization signal of the resonant heating circuit 2. During this process, the control chip 30 controls the resonant heating circuit 1 and the resonant heating circuit 2 to achieve synchronous heating.

[0062] When drive port PPG1 outputs a pulse signal, switch port SW1 outputs a low-level signal, and switch port SW2 outputs a high-level signal, drive module 1 drives power switch 1 to control heating module 1 to operate, and drive module 2 stops driving power switch 2 to control heating module 2 to operate. Synchronization detection module 1 detects the synchronization signal of resonant heating circuit 1, and synchronization detection module 2 stops detecting the synchronization signal of resonant heating circuit 2. During this process, control chip 30 only controls resonant heating circuit 1 to achieve resonant heating.

[0063] When the drive port PPG1 outputs a pulse signal, the switch port SW1 outputs a high-level signal, and the switch port SW2 outputs a low-level signal, drive module 1 stops driving power switch 1 to control heating module 1, drive module 2 drives power switch 2 to control heating module 2, and synchronization detection module 1 stops detecting the synchronization signal of resonant heating circuit 1, while synchronization detection module 2 detects the synchronization signal of resonant heating circuit 2. During this process, control chip 30 only controls resonant heating circuit 2 to perform resonant heating.

[0064] When drive port PPG1 outputs a pulse signal, switch port SW1 outputs a high-level signal, and switch port SW2 outputs a high-level signal, drive module 1 stops driving power switch 1 to control heating module 1, drive module 2 stops driving power switch 2 to control heating module 2, synchronization detection module 1 stops detecting the synchronization signal of resonant heating circuit 1, and synchronization detection module 2 stops detecting the synchronization signal of resonant heating circuit 2. Both resonant heating circuit 1 and resonant heating circuit 2 are inactive.

[0065] In some embodiments, the drive module 23 includes a drive unit 231 and a drive switch unit 232. The drive unit 231 is connected to the drive port PPG, and the drive switch unit 232 is connected to the drive unit 231 and the switch port SW. Upon receiving a low-level signal from the switch port SW, the drive unit 231 is controlled to connect to the control electrode of the power switch 22. When the drive unit 231 is connected to the control electrode of the power switch 22, if it receives a drive signal from the drive port PPG, it drives the power switch 22 to conduct.

[0066] Specifically, the drive switch unit 232 is used to control the connection or disconnection between the drive unit 231 and the control electrode of the power switch 22. When the drive switch unit 232 receives a low-level signal from the switch port SW, it controls the drive unit 231 to connect with the control electrode of the power switch 22. At this time, the drive unit 231 can drive the power switch 22 to turn on and off according to the pulse signal of the drive port PPG, thereby enabling the power switch 22 to control the heating module 21 to perform resonant heating. When the drive switch unit 232 receives a high-level signal from the switch port SW, it controls the drive unit 231 to disconnect from the control electrode of the power switch 22. At this time, the drive unit 231 cannot drive the power switch 22 to turn on and off according to the pulse signal of the drive port PPG, and the heating module 21 stops resonant heating.

[0067] Thus, the control chip 30 controls the connection and disconnection of the drive unit 231 and the power switch tube 22 through the drive switch unit 232, thereby enabling the multi-channel resonant heating circuit 20 to achieve alternating heating.

[0068] In this embodiment, the drive switching unit 232 includes a semiconductor switching device. Understandably, the high-speed switching characteristics of semiconductors allow the multi-channel resonant heating circuit 20 to alternately heat at high speed, and can expand and improve the output power range and uniformity of the resonant heating circuit 20.

[0069] Further, please refer to Figure 2 and Figure 3The drive switch unit 232 may include resistors R507 and R508 and transistor Q504. One end of resistor R507 is connected to the switch port SW. The control electrode (gate) of transistor Q504 is connected to the other end of resistor R507. The collector of transistor Q504 is connected to drive unit 231. The emitter of transistor Q504 is connected to the emitter of power switch 22. One end of resistor R508 is connected to the gate of transistor Q504, and the other end is connected to the emitter of transistor Q504.

[0070] The driving unit 231 includes transistors Q501, Q502, and Q503, resistors R501, R502, R503, R504, R505, and R506, capacitors C501, C502, C503, and C504, and diode ZD501. One end of resistor R501 is connected to a preset voltage power supply; one end of resistor R502 is connected to the other end of resistor R501 and the driving port PPG; and one end of resistors R503 and R504 are also connected to the preset voltage power supply. The gate of transistor Q501 is connected to the other end of resistor R502, the collector of transistor Q501 is connected to the other end of resistor R503, and the emitter of transistor Q501 is connected to the emitter of power switch 22. The gate of transistor Q502 is connected to the other end of resistor R503, and the collector of transistor Q502 is connected to the other end of resistor R504. The gate of transistor Q503 is connected to the other end of resistor R503, the collector of transistor Q503 is connected to the other end of resistor R504, and the emitter of transistor Q503 is connected to the emitter of power switch 22. One end of resistor R505 is connected to the emitter of transistor Q502, and the other end of resistor R505 is connected to the gate of power switch 22. One end of capacitor C504, resistor R506, and diode ZD501 is connected to the control electrode of power switch 22, and the other end of capacitor C504, resistor R506, and diode ZD501 is connected to the emitter of power switch 22. Capacitors C501, C502, and C503 are connected in parallel, with one end connected to a power supply with a preset voltage and the other end connected to the emitter of power switch 22.

[0071] When the drive port PPG outputs a drive signal (low level signal), the switch port SW outputs a low level, transistor Q501 is turned off, transistor Q504 is turned off, transistor Q502 is turned on, Q503 is turned off, and power switch 22 is turned on.

[0072] When the drive port PPG outputs a drive signal (low level signal), the switch port SW outputs a high level, transistor Q501 is turned off, transistor Q504 is turned on, transistor Q502 is turned off, Q503 is turned on, and power switch 22 is turned off.

[0073] When the drive port PPG is configured to open-drain output (high level), transistor Q501 is turned on, transistor Q502 is turned off, Q503 is turned on, and power switch 22 is turned off.

[0074] In some embodiments, the synchronization detection module 24 includes a signal detection unit 241 and a selection unit 242. The signal detection unit 241 is connected to the rectifier filter circuit 10, the power switch 22, and the synchronization detection port SYNC. The selection unit 242 is connected to the switch port SW and the signal detection unit 241. When the selection unit 242 receives a low-level signal from the switch port SW, it controls the signal detection unit 241 to detect the synchronization signal of the resonant heating circuit 20 and output it to the synchronization detection port SYNC.

[0075] Specifically, the signal detection unit 241 is connected to the second filter unit 12 of the rectifier filter circuit 10, the collector of the power switch 22, and the SYNC synchronization detection port. The signal detection unit 241 is used to detect the relative static voltage of the heating module 21 (the voltage at the connection between the second filter unit 12 and the heating module 21) and the dynamic voltage of the heating module 21 (the voltage at the connection between the heating module 21 and the collector of the power switch 22), and generates a synchronization signal based on the static voltage and the dynamic voltage and outputs it to the control chip 30.

[0076] Selection unit 242 is used to control the connection and disconnection between signal detection unit 241 and second filter unit 12, or to control the connection and disconnection between signal detection unit 241 and the collector of power switch 22, thereby controlling the detection of the synchronization signal of resonant heating circuit 20 by signal detection unit 241. When selection unit 242 receives a low-level signal from switch port SW, it can control signal detection unit 241 to connect with second filter unit 12, or control signal detection unit 241 to connect with collector of power switch 22, so that signal detection unit 241 can simultaneously detect relative static voltage and dynamic voltage, and generate synchronization signal based on static voltage and dynamic voltage. When selection unit 242 receives a high-level signal from switch port SW, it can control signal detection unit 241 to disconnect from second filter unit 12, or control signal detection unit 241 to connect with collector port of power switch 22, so that signal detection unit 241 can only detect dynamic voltage or only detect relative static voltage, and cannot detect synchronization signal.

[0077] It should be noted that when the power switch 22 is turned off, the resonant inductor current of the heating module 21 is at its maximum. The current of the resonant inductor cannot change abruptly. The resonant inductor charges the resonant capacitor C1 of the heating module 21. When the resonant inductor current is 0, the voltage of the resonant capacitor C1 reaches its maximum. At this time, the resonant capacitor C1 begins to charge the resonant inductor. The current on the resonant inductor increases first. When the relative static voltage VA = the dynamic voltage VB, the charging current on the resonant inductor reaches its maximum. Then the current gradually decreases. When the current is 0, the voltage of the resonant capacitor C1 is at its minimum. At this time, the power switch 22 needs to be turned on to synchronize the phase of the drive current with the resonant current. The synchronization signal is detected by detecting the voltage (i.e., the relative static voltage and the dynamic voltage) across the heating module 21 to detect the current phase.

[0078] Furthermore, the signal detection unit 241 includes a first detection terminal and a second detection terminal. The first detection terminal is connected to the second filter unit 12 of the rectifier filter circuit 10 and is used to detect the relative static voltage of the heating module 21. The second detection terminal is connected to the collector of the power switch 22 and is used to detect the dynamic voltage of the heating module 21. The selection unit 242 can be connected to either the first detection terminal or the second detection terminal. Understandably, when the selection unit 242 is connected to the first detection terminal, it is used to control whether the first detection terminal is connected to the second filter unit 12, that is, the selection unit 242 is used to control whether the first detection terminal detects the relative static voltage. When the selection unit 242 is connected to the second detection terminal, it is used to control whether the second detection terminal is connected to the collector of the power switch 22, that is, the selection unit 242 is used to control whether the second detection terminal detects the relative static voltage.

[0079] In this embodiment, the selection unit 242 is connected to the first detection terminal. The selection unit 242 is used to connect the first detection terminal to the rectifier filter circuit 10 when a low-level signal of the switch port SW is received, and to disconnect the first detection terminal from the rectifier filter circuit 10 when a high-level signal of the switch port SW is received.

[0080] Selection unit 242 includes a semiconductor switching device. Understandably, the high-speed switching characteristics of the semiconductor switching device allow the multi-channel resonant heating circuit 20 to alternately heat at high speed. This expands and enhances the output power range and uniformity of the resonant heating circuit 20.

[0081] Please see Figure 2 and Figure 4Specifically, the selection unit 242 includes resistors R112 and R113 and transistor Q101. One end of resistor R112 is connected to the switch port SW. The control electrode (gate) of transistor Q101 is connected to the other end of resistor R112. The collector of transistor Q101 is connected to the first detection terminal. The emitter of transistor Q101 is grounded. One end of resistor R113 is connected to the gate of transistor Q101, and the other end is connected to the emitter of transistor Q101.

[0082] The signal detection unit 241 includes resistors R101, R102, R103, R104, R105, R106, and R107, capacitors C101, C102, and C103, and a comparator U1C. One end of resistor R101 is connected to the collector of the power switch 22, one end of resistor R102 is connected to the other end of resistor R101, one end of resistor R103 is connected to the second filter unit 12, resistor R104 and capacitor C102 are connected in parallel, with one end connected to the other end of resistor R103 and the other end grounded. One end of resistor R105 is connected to resistor R102 and the other end is grounded, and capacitor C103 is connected in parallel across resistor R105. One end of capacitor C101 is connected to the positive input terminal of comparator U1C, and the other end is connected to the negative input terminal of comparator U1C. The positive input terminal of comparator U1C is connected to the other end of resistor R102, and the negative input terminal is connected to the other end of resistor R103. The output terminal is connected to the SYNC synchronization detection port. One end of resistor R106 is connected to the other end of resistor R101, and the other end of resistor R106 is connected to voltage protection detection module 25. One end of resistor R107 is connected to a 5V power supply, and the other end is connected to the SYNC synchronization detection port.

[0083] In some embodiments, the control chip 30 further includes a voltage protection port INT, and the resonant heating circuit 20 further includes a voltage protection detection module 25. The voltage protection detection module 25 is connected to the voltage protection port INT and can detect the resonant voltage of the heating module 21 and generate an adjustment signal based on the resonant voltage, so that the control chip 30 adjusts the pulse width of the drive signal according to the adjustment signal.

[0084] Thus, when the resonant voltage of the heating module 21 is too high, the control chip 30 can adjust the pulse width of the drive signal, thereby reducing the resonant voltage of the heating module 21 during resonant heating, preventing the power switch 22 from being damaged due to excessive resonant voltage, and improving the reliability of the resonant heating circuit 20.

[0085] The voltage protection detection module 25 can be directly connected to the collector of the power switch 22, or it can be connected to the second detection terminal of the signal detection unit 241 to detect the resonant voltage of the heating module 21 through the second detection terminal.

[0086] Please refer to the figure. In this embodiment, the voltage protection detection module 25 is described with the second detection terminal as an example. In this way, the voltage protection detection module 25 can share part of the voltage divider circuit with the signal detection unit 241, thereby reducing the number of components in the voltage protection detection module 25 and reducing the material cost of the electromagnetic heating device 100.

[0087] In some embodiments, the voltage protection detection module 25 includes a first voltage protection unit 251 and a second voltage protection unit 252. The first voltage protection unit 251 is connected to the collector of the power switch 22 and the voltage protection port INT, and is used to generate a first adjustment signal when the resonant voltage of the heating module 21 is detected to be greater than a first voltage threshold, so that the control chip 30 adjusts the pulse width of the drive signal according to the adjustment signal. The second voltage protection unit 252 is connected to the collector of the power switch 22 and the voltage protection port INT, and is used to generate a second adjustment signal when the resonant voltage of the heating module 21 is detected to be greater than a second voltage threshold, so that the control chip 30 stops outputting the drive signal according to the second adjustment signal, where the second voltage threshold is greater than the first voltage threshold.

[0088] In this way, the power switch 22 can be guaranteed to operate within a safe voltage range.

[0089] Please see Figure 2 and Figure 5 Specifically, the first voltage protection unit 251 includes resistors R108, R109, R110, and R111, capacitors C104 and C105, and a comparator U1D. The positive input terminal of comparator U1D is connected to a regulated power supply, and the negative input terminal is connected to the synchronization detection unit 241. Resistors R108 and R109 are connected in series and then in parallel with capacitor C104, which is then connected to the negative input terminal of comparator U1D and ground. One end of resistor R110 is connected to a 5V power supply, and the other end is connected to the output terminal of comparator U1D. One end of resistor R111 is connected to the output terminal of comparator U1D, and the other end is connected to the voltage protection detection port INT of the control chip. One end of capacitor U105 is connected to the other end of resistor R111, and the other end is grounded.

[0090] The second voltage protection unit 252 includes resistors R207 and R208, capacitor C204, and comparator U1B. Resistors R207 and R208 are connected in series, then in parallel with capacitor C204, and finally connected to the negative input terminal of comparator U1B and ground. The negative input terminal of comparator U1B is also connected to synchronization detection unit 241.

[0091] In some implementations, the control chip 30 is used to generate a pulse signal based on the synchronization signal and output it through the drive port PPG when the synchronization detection port SYNC receives a synchronization signal from any one of the resonant heating circuits 20.

[0092] Specifically, during the process of the control chip 30 driving multiple resonant heating circuits 20 to operate at the same frequency through a set of ports, a drive signal is first output through the drive port PPG, and a low-level signal is output through each switch port SW. This causes the drive module 23 of each resonant heating circuit 20 to drive the power switch 22 of the corresponding resonant heating circuit 20 to turn on, and causes each synchronization detection module 24 to detect the synchronization signal of the corresponding resonant heating circuit 20 and send it to the control chip 30. If the control chip 30 receives multiple synchronization signals, the control chip 30 generates a pulse signal according to the first received synchronization signal, and then outputs the pulse signal through the drive port PPG to the drive module 23 of each resonant heating circuit 20, so that the drive module 23 drives the corresponding power switch 22 to turn on and off, thereby controlling the heating module 21 to resonate.

[0093] This application also provides a cooking appliance, which may include the electromagnetic heating device 100 of any of the above embodiments.

[0094] In the cooking appliance of this application, a control chip connects the drive port to the drive modules of at least two resonant heating circuits, connects the switch port to the drive module and the synchronization detection module, and connects the synchronization detection port to the synchronization detection modules of at least two resonant heating circuits. This allows the control chip to control the drive modules of multiple resonant heating circuits through one drive port and multiple switch ports, thereby achieving heating control of multiple resonant heating circuits. At the same time, the switch ports can also be used to detect and control the synchronization signal in the resonant heating circuits. Thus, a single control chip can achieve drive control of multiple resonant heating circuits. On the one hand, it can achieve synchronous control of multiple resonant heating circuits, avoiding mutual interference of magnetic fields between resonant heating circuits and reducing the noise of the electromagnetic heating device. On the other hand, it reduces the material cost of the electromagnetic heating device.

[0095] 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.

[0096] 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.

[0097] 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 may include a filter rectifier circuit, multiple resonant heating circuits and a control chip. The filter rectifier circuit is connected to an AC power supply and each of the resonant heating circuits, and is used to rectify and filter the AC power supply before inputting it to the resonant heating circuit. Each of the resonant heating circuits includes a heating module, a power switch, a driving module, and a synchronization detection module. The heating module is connected to the filter and rectifier circuit and the power switch. The driving module is connected to the control electrode of the power switch and is used to drive the power switch to turn on and off to control the heating module to resonate. The synchronization detection module is connected to the rectifier and filter circuit and the power switch and is used to detect the synchronization signal of the resonant heating circuit. The control chip includes a drive port, a switch port, and a synchronization detection port. The drive port can output a pulse signal, which includes a drive signal. The switch port can output a low-level signal and a high-level signal. Each drive port is connected to at least two drive modules of the resonant heating circuit. The switch port is connected to the drive module and the synchronization detection module. Each synchronization detection port is connected to at least two synchronization detection modules of the resonant heating circuit. The synchronization detection module detects the synchronization signal and provides it to the detection module when the switch port outputs a low-level signal, and stops detecting the synchronization signal when the switch port outputs a high-level signal; The driving module drives the power switch to conduct when the switch port outputs a low-level signal and the driving port outputs a driving signal.

2. The electromagnetic heating device according to claim 1, characterized in that, The driving module includes: The drive unit is connected to the drive port; A drive switch unit is connected to the drive unit and the switch port. When a low-level signal is received from the switch port, the drive unit controls the drive unit to connect to the control electrode of the power switch. When the drive unit is connected to the control electrode of the power switch, if a drive signal is received from the drive port, the drive unit controls the power switch to turn on.

3. The electromagnetic heating device according to claim 2, characterized in that, The drive switch unit includes semiconductor switching devices.

4. The electromagnetic heating device according to claim 1, characterized in that, The synchronous detection module includes: The signal detection unit is connected to the rectifier filter circuit, the power switch, and the synchronization detection port, respectively. The selection unit, connected to the switch port and the signal detection unit, is used to control the signal detection unit to detect the synchronization signal of the resonant heating circuit and output it to the synchronization detection port when a low-level signal is received from the switch port.

5. The electromagnetic heating device according to claim 4, characterized in that, The signal detection unit includes a first detection terminal and a second detection terminal. The first detection terminal is connected to the rectifier filter circuit and is used to detect the relative static voltage of the heating module. The second detection terminal is connected to the power switch and is used to detect the dynamic voltage of the heating module.

6. The electromagnetic heating device according to claim 5, characterized in that, The selection unit is connected to the first detection terminal. The selection unit is used to connect the first detection terminal to the rectifier filter circuit when a low-level signal is received from the switch port, and to disconnect the first detection terminal from the rectifier filter circuit when a high-level signal is received from the switch port.

7. The electromagnetic heating device according to claim 5, characterized in that, The selection unit includes a semiconductor switching device.

8. The electromagnetic heating device according to claim 6, characterized in that, The control chip also includes a voltage protection port, and the resonant heating circuit also includes a voltage protection detection module. The voltage protection detection module is connected to the voltage protection port and can detect the resonant voltage of the heating module and generate an adjustment signal based on the resonant voltage, so that the control chip adjusts the pulse width of the drive signal according to the adjustment signal.

9. The electromagnetic heating device according to claim 8, characterized in that, The voltage protection detection module includes: The first voltage protection unit, connected to the power switch and the voltage protection port, is used to generate a first adjustment signal when the resonant voltage of the heating module is detected to be greater than a first voltage threshold, so that the control chip adjusts the pulse width of the drive signal according to the adjustment signal. The second voltage protection unit is connected to the power switch and the voltage protection port. It is used to generate a second adjustment signal when the resonant voltage of the heating module is detected to be greater than the second voltage threshold, so that the control chip stops outputting the drive signal according to the second adjustment signal. The second voltage threshold is greater than the first voltage threshold.

10. The electromagnetic heating device according to claim 8, characterized in that, The voltage protection detection module is connected to the second detection terminal to detect the resonant voltage of the heating module through the second detection terminal.

11. The electromagnetic heating device according to claim 1, characterized in that, The control chip is used for: When the synchronization detection port receives a synchronization signal from any of the resonant heating circuits, the pulse signal is generated based on the synchronization signal and output through the drive port.

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

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