Synchronous control circuit and method of induction cooker

Abstract

The invention discloses a synchronous control circuit of an induction cooker, and the circuit comprises a filtering module which is connected to a power grid input end VIN; the resonance module is connected with the filtering module; a collector electrode of the IGBT power tube is connected with the resonance module, and an emitter electrode of the IGBT power tube is grounded; and the single-end synchronous control module is connected with the resonance module and is used for detecting the resonance voltage output by the resonance module and generating a trigger signal when the resonance voltage is at a zero-crossing moment or a valley bottom moment, and the trigger signal is set to enable the IGBT power tube to be conducted so as to enable the resonance module to start to store energy. According to the synchronous control circuit of the induction cooker, the trigger signal is generated by accurately detecting the zero-crossing moment and the valley moment of the resonance voltage, so that the IGBT power tube can be switched on at the optimal time, the energy conversion efficiency and stability of the system are improved, the switching loss is reduced, and the heating performance and reliability of the induction cooker are improved.

Description

Technical Field

[0001] The invention relates to the field of circuit design, and in particular to a synchronous control circuit and method for an induction cooker. Background Art

[0002] Induction cooker is a commonly used electrical appliance with high energy conversion efficiency and convenient use. It is widely used in daily life, commercial cooking and industrial fields. The basic circuit principle of induction cooker is to convert the mains power into direct current through a bridge rectifier filter circuit, and then convert it into high-frequency alternating current through voltage resonance conversion. Figure 1 The topological structure diagram of the synchronous control circuit of the induction cooker in the prior art is shown. Figure 1 , the synchronous control circuit of the induction cooker includes a filter module 101, a resonance module 102, a control module 103 and an IGBT switch tube. Among them, the control module 103 includes a third comparator CMP3 and a fourth comparator CMP4, the in-phase input terminal of the third comparator CMP3 is connected to the first terminal A of the resonance module 102, the reverse input terminal is connected to the second terminal B of the resonance module 102, and the output terminal is connected to the reverse input terminal of the fourth comparator CMP4 through the third capacitor C3. The reverse input terminal D of the fourth comparator CMP4 is also connected to the power supply 5V through the second resistor R2, the in-phase input terminal is connected to the reference voltage VREF, and the output terminal is connected to the IGBT switch tube to control the conduction and shutdown of the IGBT switch tube.

[0003] Figure 2 The signal waveform diagram of the synchronous control circuit of the induction cooker in the prior art is shown. Figure 2 , when the voltage phases of point A and point B are exchanged, the output of the third comparator CMP3 flips, and at the moment when the third comparator CMP3 changes from a high level to a low level, the voltage at point D is pulled down, making its voltage less than the reference voltage VREF. At this time, the fourth comparator CMP4 outputs a high-level control signal to drive the IGBT switch tube to turn on, and the resonant circuit begins to store energy. The prior art solution can simultaneously obtain the positive half-cycle and negative half-cycle information of the resonant voltage, thereby accurately judging the phase and amplitude of the resonant voltage, ensuring that the IGBT switch tube is turned on and off at the best time, reducing switching losses and improving system efficiency. This two-terminal detection method has been widely used in the prior art, and its application principle is mature and complete. It has become a technical solution commonly used by technicians in this field, forming a technical bias. Summary of the invention

[0004] However, the inventors found that the two-end detection also has certain limitations during the research process. When the input voltage is low or the output power is low, the energy input to the resonance module 102 is greatly reduced, resulting in a significant reduction in the resonance amplitude. At this time, due to the delay effect of the RC circuit in the control module 103, the accuracy of the voltage phase detection is reduced, so that the third comparator CMP3 cannot accurately output the signal, thereby affecting the normal operation of the fourth comparator CMP4, and may eventually cause the system to enter a stop state and lose the effective switch control function. In addition, the zero-crossing opening method requires that the resonant voltage rises to a level higher than the ground level to trigger the IGBT to turn on, which causes the body diode of the power switch to reverse conduct under the action of negative current, increasing the conduction loss, especially when using a power switch with a MOSFET structure such as SiC, the loss is more significant. At the same time, the traditional two-end detection scheme requires the construction of two independent detection loops, which not only increases the complexity and power consumption of the circuit, but also makes the high-voltage side wiring susceptible to electromagnetic interference, thereby reducing the reliability and anti-interference ability of the system. Therefore, the prior art has the problems of efficiency loss and reliability reduction in low power or specific application scenarios, and urgently needs to be optimized and improved.

[0005] The object of the present invention is to provide a synchronous control circuit and method for an induction cooker, which can improve the accuracy of synchronous control and system reliability, ensure that the output signal is not affected by input voltage and output power, and at the same time simplify the circuit structure, reduce power consumption and cost.

[0006] To achieve the above object, the present invention discloses the following technical solution:

[0007] In one aspect, the present invention provides a synchronous control circuit for an induction cooker, comprising:

[0008] A filter module connected to a grid input terminal VIN;

[0009] A resonance module connected to the filter module;

[0010] An IGBT power tube, the collector of which is connected to the resonant module and the emitter of which is grounded;

[0011] The single-ended synchronous control module is connected to the resonance module, and is used to detect the resonant voltage output by the resonance module, and generate a trigger signal when the resonant voltage is at a zero-crossing moment or a valley moment, and the trigger signal is configured to turn on the IGBT power tube, thereby causing the resonance module to start storing energy.

[0012] Optionally, the resonance module includes a first inductor L1 and a first capacitor C1, the first inductor L1 and the first capacitor C1 are connected in parallel, and a first end of the first inductor L1 is connected to the filtering module, and a second end is connected to the single-ended synchronous control module and the collector of the IGBT power tube.

[0013] Optionally, the single-ended synchronization control module includes:

[0014] A zero-crossing detection unit comprises a first comparator CMP1, wherein an inverting input terminal of the first comparator CMP1 is connected to the second end of the first inductor L1, and a non-inverting input terminal of the first comparator CMP1 is grounded;

[0015] The zero-crossing detection unit is configured to generate a zero-crossing signal S11 when the voltage at the second terminal of the first inductor L1 is lower than zero.

[0016] Optionally, the single-ended synchronization control module further includes:

[0017] A valley detection unit, comprising a second comparator CPM2, wherein a non-inverting input terminal of the second comparator CPM2 is connected to the second end of the first inductor L1, a reverse input terminal is grounded via a second capacitor C2, and the reverse input terminal is further connected to the second end of the first inductor L1 via a first resistor R1;

[0018] The valley detection unit is configured to generate a valley signal S22 when the voltage at the second terminal of the first inductor L1 is at the valley moment.

[0019] Optionally, the single-ended synchronization control module further includes:

[0020] a logic unit, a first input terminal of which is connected to the output terminal of the zero-crossing detection unit, and a second input terminal of which is connected to the output terminal of the valley detection unit;

[0021] The logic unit is configured to receive the zero-crossing signal S11 and the valley signal S22, and generate a trigger signal when the zero-crossing detection unit generates the zero-crossing signal S11 or the valley detection unit generates the valley signal S22.

[0022] Optionally, the single-ended synchronization control module further includes:

[0023] A timing reset unit, whose input end is connected to the logic unit, is configured to maintain a preset time after the trigger signal is generated, and reset the trigger signal after the preset time is reached.

[0024] Optionally, the synchronous control circuit of the induction cooker further includes:

[0025] The control module is connected to the output end of the timing reset unit, and is used to receive the trigger signal and generate a control instruction in combination with the output power set by the user when the trigger signal is generated. The control instruction is set to control the on-time and off-time of the IGBT power tube.

[0026] Optionally, the synchronous control circuit of the induction cooker further includes:

[0027] A driving module, one end of which is connected to the control module and the other end of which is connected to the gate of the IGBT power tube, is used to generate a driving signal according to the control instruction to control the on and off of the IGBT power tube.

[0028] Optionally, the logic unit is an OR gate circuit structure, configured to select the zero-crossing signal S11 or the valley signal S22 received first as the trigger signal.

[0029] Another aspect of the present invention provides a synchronous control method for an induction cooker, comprising:

[0030] The resonant voltage output by the resonant module is detected by the single-ended synchronous control module to obtain the zero-crossing moment and the valley moment of the resonant voltage;

[0031] When the resonant voltage is at a zero-crossing moment or a valley moment, generating a trigger signal;

[0032] According to the trigger signal, the IGBT power tube is controlled to be turned on so that the resonant module starts to store energy;

[0033] According to the output power set by the user, the turn-off moment of the IGBT power tube is controlled, so that the resonance module enters a high-frequency resonance state and transmits energy to the cooker.

[0034] The effects provided in the content of the invention are only the effects of the embodiments, not all the effects of the invention. One of the above technical solutions has the following advantages or beneficial effects:

[0035] The synchronous control circuit of the induction cooker provided in the embodiment of the present application detects the zero-crossing moment and the valley moment of the resonant voltage in real time through a single-ended synchronous control module, and generates a trigger signal Son, ensuring that the IGBT power tube is turned on at the best time and is not affected by changes in input voltage and output power, thereby improving the accuracy and stability of the synchronous control. At the same time, the present invention avoids the problem of oscillation stopping caused by low input voltage or low output power in traditional circuits by accurately controlling the turn-on timing of the IGBT power tube, while reducing the reverse conduction loss of the IGBT power tube when it is turned on at zero crossing, thereby improving the reliability and energy conversion efficiency of the system. In addition, the present invention adopts a single-ended synchronous control module, and only needs to extract the resonant voltage signal from one side of the resonant module, thereby avoiding the complex structure of the traditional two-terminal detection circuit, and reducing the number of circuit elements and wiring difficulty.

[0036] Furthermore, the present invention ensures that the circuit can accurately trigger the signal at the zero-crossing moment or valley moment of the resonant voltage through the design of the zero-crossing detection unit and the valley detection unit, thereby significantly improving the synchronization control accuracy, reducing the risk of false triggering, and enabling the circuit to respond promptly according to the change of the resonant voltage, and optimizing the control timing of the IGBT power tube. At the same time, the logic unit receives the output signals of the zero-crossing detection unit and the valley detection unit, selects the best triggering moment, and ensures that the conduction operation of the IGBT power tube is both efficient and accurate, avoiding unnecessary energy waste. In addition, the control module generates control instructions based on the received trigger signal and the output power set by the user, and accurately regulates the conduction and shutdown moments of the IGBT power tube. The drive module 250 generates drive signals based on these control instructions, further improving the response speed and accuracy of the IGBT power tube control, thereby achieving more efficient energy conversion and more stable system operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0038] Figure 1 The topological structure diagram of the synchronous control circuit of an induction cooker in the prior art is shown;

[0039] Figure 2 The signal waveform diagram of the synchronous control circuit of the induction cooker in the prior art is shown;

[0040] Figure 3 A block diagram of a single-ended synchronous control circuit for an induction cooker according to an embodiment of the present invention is shown;

[0041] Figure 4 shows a circuit topology diagram of a single-ended synchronous control module 230 according to some embodiments of the present invention;

[0042] Figure 5 Shows Figure 4 The signal waveform diagram of the single-ended synchronous control module 230;

[0043] Figure 6 A schematic flow chart of a synchronous control method for an induction cooker according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0045] It should be noted that references to "one embodiment", "embodiment", "example embodiment", etc. in this specification refer to the embodiment being described which may include specific features, structures or characteristics, but not every embodiment must include these specific features, structures or characteristics. In addition, such expressions do not refer to the same embodiment. Furthermore, when describing specific features, structures or characteristics in conjunction with an embodiment, whether or not there is an explicit description, it is indicated that incorporating such features, structures or characteristics into other embodiments is within the knowledge of those skilled in the art.

[0046] In addition, certain words are used in the specification and subsequent claims to refer to specific components or parts. Those with ordinary knowledge in the relevant field should understand that manufacturers can use different nouns or terms to refer to the same component or part. This specification and subsequent claims do not use differences in names as a way to distinguish components or parts, but use differences in the functions of components or parts as the criteria for distinction. "Including" and "including" mentioned throughout the specification and subsequent claims are open-ended terms and should be interpreted as "including but not limited to". In addition, the word "connected" here includes any direct and indirect electrical connection means. Indirect electrical connection means include connection through other devices.

[0047] Figure 3 FIG. 2 shows a block diagram of a single-ended synchronous control circuit of an induction cooker according to an embodiment of the present invention. Figure 3 As shown, the single-ended synchronous control circuit of the induction cooker includes a filter module 210, a resonance module 220, a single-ended synchronous control module 230 and an IGBT power tube. Among them, the filter module 210 is connected to the grid input terminal VIN. The resonance module 220 is connected to the filter module 210. The collector of the IGBT power tube Q1 is connected to the resonance module 220, and the emitter is grounded. The single-ended synchronous control module 230 is connected to the resonance module 220, and is used to detect the resonant voltage output by the resonance module 220, and generate a trigger signal Son when the resonant voltage is at a zero-crossing moment or a valley moment. The trigger signal Son is set to enable the IGBT power tube Q1 to be turned on, so that the resonance module 220 starts to store energy.

[0048] In this embodiment, the working principle of the single-ended synchronous control circuit of the induction cooker is as follows: when the circuit is powered on, the filter module 210 filters the input voltage to reduce the impact of power grid fluctuations on the circuit and provides a relatively stable voltage to the resonance module 220. During the operation of the circuit, the single-ended synchronous control module 230 monitors the output voltage of the resonance module 220 in real time. When the resonance voltage is at the zero-crossing moment or the valley moment, the single-ended synchronous control module 230 generates a trigger signal Son to turn on the IGBT power tube Q1. At this time, the resonance module 220 starts to store energy to ensure that the circuit transmits energy at the appropriate time, thereby improving the synchronization control accuracy and stability of the system.

[0049] According to the scheme of the embodiment of the present invention, the zero-crossing moment and the valley moment of the resonant voltage are detected in real time by the single-ended synchronous control module 230, and the trigger signal Son is generated to ensure that the IGBT power tube Q1 is turned on at the best time and is not affected by the changes in input voltage and output power, thereby improving the accuracy and stability of the synchronous control. At the same time, the present invention avoids the problem of stopping vibration caused by low input voltage or low output power in the traditional circuit by accurately controlling the turn-on timing of the IGBT power tube Q1, and at the same time reduces the reverse conduction loss of the IGBT power tube Q1 when it is turned on at zero crossing, thereby improving the reliability and energy conversion efficiency of the system. In addition, the present invention adopts a single-ended synchronous control module 230, and only needs to extract the resonant voltage signal from one side of the resonant module 220, thereby avoiding the complex structure of the traditional two-terminal detection circuit, and reducing the number of circuit elements and wiring difficulty.

[0050] refer to Figure 3 , the resonance module 220 includes a first inductor L1 and a first capacitor C1, the first inductor L1 and the first capacitor C1 are connected in parallel, and the first end of the first inductor L1 is connected to the filter module 210, and the second end is connected to the collector of the single-ended synchronous control module 230 and the IGBT power tube Q1. When the IGBT power tube Q1 is turned on, the resonance module 220 obtains energy from the power grid through the filter module 210 and stores energy. As the IGBT power tube Q1 is turned off, the resonance module 220 forms a resonant loop in the circuit by relying on the interaction between the inductor and the capacitor, so that the electric energy is periodically exchanged between the inductor and the capacitor at a specific frequency, thereby maintaining a stable resonant state. This process ensures that the circuit can provide efficient and stable high-frequency electric energy to the load, while optimizing the energy transmission efficiency, reducing the loss caused by the hard switching of the switching device, reducing electromagnetic interference (EMI), and improving the overall reliability and service life of the system.

[0051] Figure 4 FIG. 2 shows a circuit topology diagram of a single-ended synchronous control module 230 according to some embodiments of the present invention. Figure 4As shown, the single-ended synchronous control module 230 includes a zero-crossing detection unit 231, a valley detection unit 232, a logic unit 233 and a timing reset unit 234. Among them, the zero-crossing detection unit 231 includes a first comparator CMP1, the inverting input terminal of the first comparator CMP1 is connected to the second end of the first inductor L1, and the non-inverting input terminal is grounded. The zero-crossing detection unit 231 is configured to generate a zero-crossing signal S11 when the voltage at the second end of the first inductor L1 is lower than zero. The valley detection unit 232 includes a second comparator CPM2, the non-inverting input terminal of the second comparator CPM2 is connected to the second end of the first inductor L1, the inverting input terminal is grounded through the second capacitor C2, and the inverting input terminal is also connected to the second end of the first inductor L1 through the first resistor R1. The valley detection unit 232 is configured to generate a valley signal S22 when the voltage at the second end of the first inductor L1 is at the valley moment.

[0052] Figure 5 Shows Figure 4 The signal waveform diagram of the single-ended synchronous control module 230 is shown in FIG. Figure 5 In this embodiment, when the circuit is running, the single-ended synchronous control module 230 monitors the voltage state of the second terminal of the first inductor L1 in real time through the zero-crossing detection unit 231 and the valley detection unit 232 to accurately determine the turn-on time of the IGBT power tube Q1. When the IGBT power tube Q1 is turned off, the voltage at the second terminal of the first inductor L1 is as follows: Figure 6 The LC resonance waveform shown is V L The zero-crossing detection unit 231 continuously detects V L The zero-crossing moment of V L The zero-crossing detection unit 231 is connected to the first input terminal of the logic unit 233 to output a first signal S1 to the logic unit 233, wherein the first signal S1 includes a zero-crossing signal S11. That is, when V L When the voltage is lower than 0V, since the non-inverting input terminal of the first comparator CMP1 is grounded, the zero-crossing signal S11 output by the first comparator CMP1 is a high level signal.

[0053] However, when the input voltage is low or the output power is low, the voltage at the second end of the first inductor L1 may not reach the zero-crossing state, causing the zero-crossing detection module to be unable to detect V LThe zero crossing point of the first inductor L1. At this time, the single-ended synchronous control module 230 detects the voltage of the second terminal of the first inductor L1 through the valley detection unit 232. The valley detection unit 232 is connected to the second input terminal of the logic unit 233 to output the second signal S2 to the logic unit 233, wherein the second signal S2 includes the valley signal S22. Specifically, when the voltage of the second terminal of the first inductor L1 decreases, the voltage of the in-phase input terminal of the second comparator CMP2 is lower than the voltage of the reverse input terminal, and the second signal S2 output by the valley detection unit 232 is a low-level signal; when the voltage of the second terminal of the first inductor L1 starts to rise, the voltage of the in-phase input terminal of the second comparator CMP2 is higher than the voltage of the reverse input terminal, and the valley signal S22 output by the valley detection unit 232 is a high-level signal. The moment when the valley signal S22 is generated is the valley moment of the voltage of the second terminal of the first inductor L1.

[0054] In one embodiment, see Figure 4 and Figure 5 The single-ended synchronous control module 230 further includes a logic unit 233, a first input end of which is connected to the output end of the zero-crossing detection unit 231, and a second input end of which is connected to the output end of the valley detection unit 232. The logic unit 233 is configured to generate a trigger signal Son at the moment when the zero-crossing detection unit 231 generates the zero-crossing signal S11 or the valley detection unit 232 generates the valley signal S22. The level corresponding to the trigger signal Son is a high level, and the IGBT power tube Q1 can be turned on under the high level signal.

[0055] In one embodiment, reference Figure 4 The single-ended synchronous control module 230 further includes a timing reset unit 234, whose input end is connected to the logic unit 233 and is configured to maintain a preset time after the trigger signal Son is generated, and reset the trigger signal after the preset time is reached. Figure 5 , the logic unit 233 is connected to the input end of the timing reset unit 234 through the output end, and outputs the third signal S3 to the timing reset unit 234, wherein the third signal S3 includes the trigger signal Son. As described above, when the logic unit 233 receives the zero-crossing signal S11 or the valley signal S22, the trigger signal Son is generated. When the timing reset unit 234 receives the trigger signal Son, the high level state of the trigger signal Son is maintained for a preset time. When the preset time is reached, the trigger signal Son is forced to be reset to a low level. At this time, the trigger signal Son disappears, and the logic unit 233 outputs a low level signal, i.e., the third signal S3.

[0056] In one embodiment, the logic unit 233 is an OR gate circuit structure, configured to select the first received zero-crossing signal S11 or the valley signal S22 as the trigger signal Son.

[0057] In this embodiment, the logic unit 233 receives the zero-crossing signal S11 and the valley signal S22, and determines the arrival order of the zero-crossing moment and the valley moment of the resonant voltage, and preferentially selects the signal corresponding to the moment that arrives first as the trigger signal Son, and outputs it to the control module 240 to control the conduction of the IGBT power tube Q1, so that the resonant module 220 enters the energy storage state, thereby ensuring that the circuit performs energy conversion at the optimal time, improving the synchronization control accuracy, improving the system stability and energy utilization, and optimizing the heating effect of the induction cooker.

[0058] In one embodiment, the synchronous control circuit of the induction cooker also includes a control module 240, which is connected to the output end of the timing reset unit 234, and is used to generate a control instruction in combination with the output power set by the user at the moment when the trigger signal Son is generated. The control instruction is set to control the on-time and off-time of the IGBT power tube Q1. In this embodiment, the control module 240 adopts the XYF173-N001 model. When the trigger signal Son arrives, the control module 240 first determines the current power setting, and calculates the optimal on-time and off-time of the IGBT power tube Q1 according to the power setting. For higher power requirements, the control module 240 appropriately extends the on-time of the IGBT to increase the energy input of the resonant circuit; for lower power requirements, the on-time of the IGBT is shortened to ensure that the power output meets the set requirements while avoiding overheating or energy waste. Based on the calculated optimal on-time and off-time of the IGBT power tube Q1, a control instruction is generated and sent to the drive module 250 to control the on-time of the IGBT power tube Q1.

[0059] In one embodiment, the synchronous control circuit of the induction cooker further includes a driving module 250, one end of which is connected to the control module 240, and the other end is connected to the gate of the IGBT power tube Q1, and is used to generate a driving signal according to the control instruction to control the on and off of the IGBT power tube Q1. In this embodiment, the driving module 250 receives the control instruction generated by the control module 240 and converts it into a suitable driving signal to accurately control the on and off of the IGBT power tube Q1.

[0060] According to the above embodiment, the present invention ensures that the circuit can accurately trigger the signal Son at the zero-crossing moment or the valley moment of the resonant voltage through the design of the zero-crossing detection unit 231 and the valley detection unit 232, thereby significantly improving the synchronization control accuracy, reducing the risk of false triggering, and enabling the circuit to respond in time according to the change of the resonant voltage, and optimizing the control timing of the IGBT power tube Q1. At the same time, the logic unit 233 receives the output signals of the zero-crossing detection unit 231 and the valley detection unit 232, selects the best triggering moment, and ensures that the conduction operation of the IGBT power tube Q1 is both efficient and accurate, avoiding unnecessary energy waste. In addition, the control module 240 generates control instructions according to the received trigger signal Son and the output power set by the user, and accurately regulates the conduction and shutdown moments of the IGBT power tube Q1. The drive module 250 generates drive signals according to these control instructions, further improving the response speed and accuracy of the control of the IGBT power tube Q1, thereby achieving more efficient energy conversion and more stable system operation.

[0061] Of course, it should be noted that Figure 4 The circuit structure of the single-ended synchronous control module 230 shown is only a preferred circuit structure for achieving the purpose of the present invention. In other embodiments, each circuit module or device may also use other circuit structures that can achieve the same function, and the present application is not limited thereto.

[0062] Figure 6 FIG. 2 is a flow chart showing a synchronous control method for an induction cooker according to an embodiment of the present invention. Figure 6 As shown, the synchronous control method of the induction cooker includes:

[0063] Step S100 , detecting the resonant voltage output by the resonant module 220 through the single-ended synchronous control module 230 , and obtaining the zero-crossing moment and the valley moment of the resonant voltage.

[0064] Step S200: When the resonant voltage is at a zero-crossing moment or a valley moment, a trigger signal Son is generated.

[0065] Step S300: According to the trigger signal, the IGBT power tube Q1 is controlled to be turned on, so that the resonance module 220 starts to store energy.

[0066] Step S400, according to the output power set by the user, the turn-off moment of the IGBT power tube Q1 is controlled, so that the resonance module 220 enters a high-frequency resonance state and transmits energy to the cooker.

[0067] In the synchronous control method of the induction cooker, the specific implementation of each module and unit refers to the relevant content of the embodiment of the synchronous control circuit of the induction cooker, which will not be described in detail here.

[0068] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0069] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A synchronous control circuit for an induction cooker, characterized in that: include: A filter module connected to a grid input terminal VIN; A resonance module connected to the filter module; An IGBT power tube, the collector of which is connected to the resonant module and the emitter of which is grounded; The single-ended synchronous control module is connected to the resonance module, and is used to detect the resonant voltage output by the resonance module, and generate a trigger signal when the resonant voltage is at a zero-crossing moment or a valley moment, and the trigger signal is configured to turn on the IGBT power tube, thereby causing the resonance module to start storing energy.

2. The circuit according to claim 1, characterized in that The resonance module includes a first inductor L1 and a first capacitor C1, the first inductor L1 and the first capacitor C1 are connected in parallel, and a first end of the first inductor L1 is connected to the filter module, and a second end is connected to the single-ended synchronous control module and the collector of the IGBT power tube.

3. The circuit according to claim 2, characterized in that The single-ended synchronous control module comprises: A zero-crossing detection unit comprises a first comparator CMP1, wherein an inverting input terminal of the first comparator CMP1 is connected to the second end of the first inductor L1, and a non-inverting input terminal of the first comparator CMP1 is grounded; The zero-crossing detection unit is configured to generate a zero-crossing signal S11 when the voltage at the second terminal of the first inductor L1 is lower than zero.

4. The circuit according to claim 3, characterized in that The single-ended synchronous control module also includes: A valley detection unit, comprising a second comparator CPM2, wherein a non-inverting input terminal of the second comparator CPM2 is connected to the second end of the first inductor L1, a reverse input terminal is grounded via a second capacitor C2, and the reverse input terminal is further connected to the second end of the first inductor L1 via a first resistor R1; The valley detection unit is configured to generate a valley signal S22 when the voltage at the second terminal of the first inductor L1 is at a valley moment.

5. The circuit according to claim 4, characterized in that The single-ended synchronous control module also includes: a logic unit, a first input terminal of which is connected to the output terminal of the zero-crossing detection unit, and a second input terminal of which is connected to the output terminal of the valley detection unit; The logic unit is configured to generate a trigger signal when the zero-crossing detection unit generates a zero-crossing signal S11 or the valley detection unit generates a valley signal S22.

6. The circuit according to claim 5, characterized in that The single-ended synchronous control module also includes: The timing reset unit, whose input end is connected to the logic unit, is configured to maintain a preset time after the trigger signal is generated, and reset the trigger signal after the preset time is reached.

7. The circuit according to claim 6, characterized in that Also includes: The control module is connected to the output end of the timing reset unit and is used to generate a control instruction in combination with the output power set by the user when the trigger signal is generated. The control instruction is configured to control the on-time and off-time of the IGBT power tube.

8. The circuit according to claim 7, characterized in that Also includes: A driving module, one end of which is connected to the control module and the other end of which is connected to the gate of the IGBT power tube, is used to generate a driving signal according to the control instruction to control the on and off of the IGBT power tube.

9. The circuit according to claim 5, characterized in that The logic unit is an OR gate circuit structure, and is configured to select the zero-crossing signal S11 or the valley signal S22 received first as a trigger signal.

10. A synchronous control method for an induction cooker, characterized in that: The method comprises: The resonant voltage output by the resonant module is detected by the single-ended synchronous control module to obtain the zero-crossing moment and the valley moment of the resonant voltage; When the resonant voltage is at a zero-crossing moment or a valley moment, generating a trigger signal; According to the trigger signal, the IGBT power tube is controlled to be turned on so that the resonant module starts to store energy; According to the output power set by the user, the turn-off moment of the IGBT power tube is controlled, so that the resonance module enters a high-frequency resonance state and transmits energy to the cooker.

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