Electromagnetic heating IGBT (Insulated Gate Bipolar Translator) driving circuit and electromagnetic cooking utensil

Abstract

The invention provides an electromagnetic heating IGBT (Insulated Gate Bipolar Translator) driving circuit, which is characterized in that a driving signal input end is used for receiving a driving signal for driving an IGBT; the push-pull module is used for controlling the conducting state of the IGBT; the driving module is connected with a driving signal input end to obtain a driving signal so as to form a driving working signal for driving the push-pull module to work; the driving power supply is used for supplying power to the IGBT driving circuit; the driving circuit further comprises an adjusting module and a zero-crossing sampling module, the output end of the adjusting module is connected with the driving module, the input end of the adjusting module is connected with the output end of the zero-crossing sampling module, and the adjusting module adjusts a driving working signal of the driving module according to an alternating-current zero-crossing signal obtained by the zero-crossing sampling module. According to the invention, the conduction speed of the IGBT can be reduced, and the explosion risk and the switching-on noise can be reduced. According to the invention, the conduction speed of the IGBT can be controlled based on the AC zero-crossing signal, the explosion risk and the opening noise can be reduced, and the energy loss can be reduced.

Description

Technical Field

[0001] The invention relates to the technical field of electromagnetic heating, in particular to an IGBT driving circuit for electromagnetic heating and an electromagnetic cooking appliance. Background Art

[0002] At present, most of the common induction cookers on the market use electromagnetic resonant circuits composed of IGBTs (Insulated Gate Bipolar Transistor) to realize their electromagnetic heating functions, and most of the electromagnetic resonant circuits work in parallel resonance. However, during the process of IGBT wave loss or intermittent heating, the IGBT may be turned off for a long time. In this case, the voltage of the IGBT collector will gradually increase with the charging of the capacitor, usually increasing to 1.4 times the AC power, which will cause the IGBT to be turned on in the subsequent conduction. The presence of high on-voltage will cause the IGBT to have an excessively high on-current at the moment of conduction. Both high on-voltage and high on-current will increase the risk of explosion and working noise of the induction cooker, affecting the safety of the induction cooker and the user experience. Summary of the invention

[0003] In view of the problems that when the existing induction cooker performs intermittent heating or continuous heating by using an electromagnetic resonant circuit composed of IGBT, the on-state voltage and on-state current of the IGBT are too high, the risk of machine explosion and the working noise are increased, the purpose of the present invention is to provide an IGBT driving circuit for electromagnetic heating and an electromagnetic cooking appliance, which utilizes the characteristic that the energy of alternating current is the lowest at the zero-crossing moment, and adjusts the on-state speed of the IGBT according to the alternating current zero-crossing signal, so as to realize slow turning on of the IGBT at the zero-crossing moment and fast turning on of the IGBT at the non-zero point moment, effectively avoiding the problem of excessive on-state voltage and on-state current of the IGBT, reducing the risk of machine explosion and the start-up noise, and ensuring the safety of the induction cooker and the user experience.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] An IGBT driving circuit for electromagnetic heating, comprising:

[0006] A driving signal input terminal, used to receive a driving signal for driving the IGBT;

[0007] Push-pull module, used to control the conduction state of IGBT;

[0008] A driving module connected to a driving signal input terminal to obtain a driving signal to form a driving working signal for driving the push-pull module to work;

[0009] A driving power supply, used to supply power to the IGBT driving circuit;

[0010] It is characterized by further comprising an adjustment module and a zero-crossing sampling module.

[0011] The output end of the regulating module is connected to the driving module, and the input end is connected to the output end of the zero-crossing sampling module. The regulating module adjusts the driving working signal of the driving module according to the AC zero-crossing signal obtained by the zero-crossing sampling module.

[0012] In this technical solution, the driving working signal is adjusted by the AC zero-crossing signal, so as to realize the adjustment of the conduction speed of the IGBT. By collecting the AC zero-crossing signal of the AC power, the zero-crossing moment and the non-zero-crossing moment of the AC power can be accurately distinguished. The energy possessed at the zero-crossing moment and the non-zero-crossing moment of the AC power is different. The driving working signal is adjusted according to the energy characteristics of the AC power at different moments. Adjusting the driving working signal is equivalent to adjusting the starting condition of the input end of the push-pull module. The conduction speed of the IGBT can be adjusted by adjusting the opening speed of the push-pull module, which can effectively solve the risk of explosion caused by the excessive on-voltage and on-current of the IGBT and the high noise caused by the opening, and ensure the safety of the induction cooker and the user experience.

[0013] The present invention is further configured as follows: when the AC zero-crossing signal is at the zero-crossing moment, the regulating module is turned off to reduce the opening speed of the push-pull module at the zero-crossing moment;

[0014] When the AC zero-crossing signal is at a non-zero-crossing moment, the regulating module is enabled to increase the opening speed of the push-pull module at the non-zero-crossing moment.

[0015] Through this setting, the zero-crossing moment and non-zero-crossing moment of the AC power are divided based on the AC zero-crossing signal, and the opening speed of the push-pull module can be reduced by turning off the adjustment module at the zero-crossing moment of the AC power, thereby achieving the purpose of slowly turning on the IGBT, thereby reducing the risk of machine explosion and opening noise. At the non-zero-crossing moment, the opening speed of the push-pull module is increased by controlling the enabling of the adjustment module, thereby achieving the purpose of quickly starting the IGBT and further reducing the energy loss when the IGBT is started.

[0016] The present invention is further configured as follows: the regulating module is a current regulating module, and the current regulating module regulates the current at the input end of the push-pull module according to an AC zero-crossing signal.

[0017] Through this configuration, since the turn-on speed of the push-pull module can be determined by the current size of its input end, increasing the input current can increase the turn-on speed of the push-pull module, while reducing the input current can reduce the turn-on speed of the push-pull module. Therefore, the turn-on speed of the push-pull module can be controlled by adjusting the current, thereby achieving the purpose of adjusting the conduction speed of the IGBT. The control method for adjusting the conduction speed of the IGBT is simple and efficient.

[0018] The present invention is further configured as follows: the current regulating module includes a driving speed regulating circuit,

[0019] The driving speed regulating circuit is closed at the zero-crossing moment according to the AC zero-crossing signal to reduce the current at the input end of the push-pull module;

[0020] The driving speed regulating circuit is enabled at a non-zero point according to the AC zero-crossing signal to increase the current at the input end of the push-pull module.

[0021] Through this setting, the current at the input end of the push-pull circuit can be further controlled by driving the on-off state of the speed control circuit, thereby adjusting the conduction speed of the IGBT. A pure hardware method is used to adjust the conduction speed of the IGBT, and the adjustment effect is more stable and reliable.

[0022] The present invention is further configured as follows: the regulating module includes at least one current regulating element connected in series between the input end of the push-pull module and the output end of the zero-crossing sampling module,

[0023] The current regulating element increases the resistance of the regulating module at the zero-crossing moment according to the AC zero-crossing signal to reduce the current at the input end of the push-pull module;

[0024] The current regulating element reduces the resistance of the regulating module at a non-zero-crossing moment according to the AC zero-crossing signal to increase the current at the input end of the push-pull module.

[0025] Through this setting, the current is regulated specifically by the current regulating element. The current regulating element can increase the resistance of the regulating module at the zero-crossing moment, thereby reducing the current at the input end of the push-pull module. The push-pull module can slowly turn on the IGBT to avoid the occurrence of high conduction voltage and high conduction current. At the non-zero-crossing moment, the resistance of the regulating module can be reduced, thereby increasing the current at the input end of the push-pull module. The push-pull module can quickly turn on the IGBT and reduce energy loss. The method of adjusting the current by adjusting the resistance value can also be achieved through pure hardware, the adjustment operation is simple, and the adjustment effect is more stable and reliable.

[0026] The present invention is further configured as follows: the zero-crossing sampling module includes a voltage detection element, and the zero-crossing sampling module detects the zero-crossing moment of the alternating current through the voltage detection element and generates a corresponding alternating current zero-crossing signal.

[0027] Through this setting, the voltage detection element is used to realize the detection of the zero-crossing moment of the alternating current. The energy of the alternating current is the lowest at the zero-crossing moment. By detecting the voltage of the alternating current, the zero-crossing moment can be collected, and an alternating zero-crossing signal is generated based on the detection result of the voltage detection element. The generated alternating zero-crossing signal can feedback the zero-crossing moment and the non-zero-crossing moment. After obtaining the alternating zero-crossing signal, the adjustment module can adjust the driving working signal of the driving module according to the alternating zero-crossing signal for the zero-crossing moment and the non-zero-crossing moment, thereby realizing automatic adjustment of the conduction speed of the IGBT.

[0028] The present invention is further configured such that: the voltage detection element is any one of a zero-crossing detection chip, an optocoupler zero-crossing sampling module or a buck regulator tube zero-crossing sampling module.

[0029] Through this setting, the purpose of detecting the zero-crossing moment can be achieved through any one of the zero-crossing detection chip, the optocoupler zero-crossing sampling module or the buck regulator zero-crossing sampling module, among which the optocoupler zero-crossing sampling module and the buck regulator zero-crossing sampling module can both realize the detection of the zero-crossing moment in a pure hardware manner, and the zero-crossing detection of the three all realizes the judgment of the zero-crossing moment by detecting the voltage of the alternating current, and the judgment accuracy of the zero-crossing moment of the alternating current is relatively high.

[0030] The present invention is further configured as follows: the zero-crossing sampling module includes a rectifier element and a voltage divider element connected in series in the zero-crossing sampling module, the alternating current is input into the voltage divider element through the rectifier element, and the zero-crossing sampling module outputs an alternating zero-crossing signal according to the voltage divided by the voltage divider element.

[0031] Through this configuration, AC power is converted into DC power based on the rectifying element, and then the zero-crossing moment and non-zero-crossing moment of the AC power are distinguished based on the voltage signal of the converted DC power by the voltage divider element, so that an AC zero-crossing signal is generated and output based on the zero-crossing moment and the non-zero-crossing moment. The detection method is simple and the accuracy of the detection result can be guaranteed.

[0032] The present invention is further configured to include a control signal input end of the regulating module, the control signal input end receiving an external control signal to shut down the regulating module at the zero-crossing moment of the alternating current.

[0033] Through this setting, the opening and closing of the regulation module can be controlled by an external control signal, and the regulation module can also be closed at the zero-crossing moment, thereby controlling the current at the input end of the push-pull module, realizing the adjustment of the conduction speed of the push-pull module, and then controlling and adjusting the conduction speed of the IGBT to avoid the occurrence of high conduction voltage and high conduction current.

[0034] An electromagnetic cooking appliance, an electromagnetic cooking appliance, includes a main control circuit for controlling the operation of the electromagnetic cooking appliance, the cooking appliance includes a first power operating mode and a second power operating mode, the power of the second operating mode is greater than the power of the first operating mode, and the power of the first power operating mode is not greater than 600 watts, the main control circuit includes the IGBT drive circuit in any one of the above embodiments, so that the first power operating mode and the second power operating mode are both continuous heating modes.

[0035] It should be noted that in any of the above technical solutions, the electromagnetic cooking appliance includes any one of an induction cooker, an electric rice cooker, an electric pressure cooker, and an electric hot pot.

[0036] In the description of the present invention, it should be noted that the "electromagnetic cooking appliance" mentioned in the present invention may include any cooking equipment that can cook food and to which the technical solution of the present invention can be applied, including but not limited to induction cookers, electric pressure cookers, electric rice cookers, and electric hot pots.

[0037] The beneficial effects of the present invention are:

[0038] 1. The characteristic that the energy of AC power is the lowest at the moment of zero crossing is utilized, and the driving working signal is adjusted based on the AC zero crossing signal. Based on the adjusted driving working signal, the push-pull module will have different conduction speeds, thereby controlling the IGBT to conduct at different conduction speeds at different times. Specifically, at the moment of AC power crossing zero, the conduction speed of the IGBT is slowed down, so that at the moment of IGBT conduction, there will be no high conduction voltage and high conduction current, reducing the risk of explosion and turn-on noise, ensuring the safety of the induction cooker and the user experience, and for non-zero crossing moments, the conduction speed of the IGBT is also accelerated to further reduce the energy loss when the IGBT is turned on.

[0039] 2. No software judgment and control is required. The IGBT conduction speed can be regulated and controlled based on the zero-crossing sampling signal by pure hardware, and the regulation effect is more stable and reliable.

[0040] 3. The IGBT driving circuit is integrated into the main control circuit to improve its convenience of use and reduce its cost. The main control circuit uses the IGBT driving circuit in the utility model to enable the electromagnetic cooking appliance to achieve continuous heating and cooking regardless of whether it is in the second working mode with higher power or the first working mode with lower power. Especially in the first working mode with lower power, compared with the intermittent heating mode adopted in the prior art, the user experience is greatly optimized. At the same time, since the voltage and current at the moment of IGBT conduction are reduced, the service life of the electromagnetic cooking appliance is guaranteed. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1It is a structural schematic diagram of an electromagnetic heating IGBT drive circuit of the present invention;

[0042] Figure 2 It is a comparison diagram of a driving signal when a regulating module is enabled and a signal applied to the base of an IGBT to drive the IGBT according to an embodiment of the present invention;

[0043] Figure 3 is a comparison diagram of a driving signal when a regulating module is turned off and a signal applied to the base of an IGBT to drive the IGBT according to an embodiment of the present invention;

[0044] Figure 4 It is an overall circuit diagram of an IGBT driving circuit according to an embodiment of the present invention.

[0045] Among them: 1. driving signal input terminal, 2. push-pull module, 3. driving module, 4. regulating module, 5. zero-crossing sampling module, 6. IGBT. DETAILED DESCRIPTION

[0046] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0047] An IGBT driving circuit for electromagnetic heating, such as Figure 1 As shown, including:

[0048] A driving signal input terminal 1, used for receiving a driving signal for driving the IGBT6;

[0049] Push-pull module 2, used to control the conduction state of the IGBT;

[0050] A driving module 3, connected to a driving signal input terminal to obtain a driving signal to form a driving working signal for driving the push-pull module to work;

[0051] A driving power supply, used to supply power to the IGBT driving circuit;

[0052] It also includes a regulation module 4 and a zero-crossing sampling module 5.

[0053] The output end of the regulating module is connected to the driving module, and the input end is connected to the output end of the zero-crossing sampling module. The regulating module adjusts the driving working signal of the driving module according to the AC zero-crossing signal obtained by the zero-crossing sampling module.

[0054] The driving signal is a fixed signal, and the driving signal is used to determine the on-off cycle of the IGBT. The push-pull module can control the on and off of the IGBT according to the on-off cycle of the IGBT determined by the driving signal. The on-speed of the push-pull module directly affects the on-speed of the IGBT. Therefore, in this embodiment, a driving working signal for controlling the operation of the push-pull module is provided, and the driving working signal can be adjusted directly according to the AC zero-crossing signal through the circuit structure to achieve the adjustment of the driving working signal. Thus, while driving the IGBT with a fixed on-off cycle of the IGBT, the on-speed of the IGBT can be adjusted according to the zero-crossing information contained in the AC zero-crossing signal. The above-mentioned adjustment of the driving working signal is equivalent to the adjustment and control of the start-up conditions of the push-pull module.

[0055] The zero-crossing sampling module can distinguish between the zero-crossing moment and the non-zero-crossing moment of the AC power. The AC power has the lowest energy at the zero-crossing moment. The startup speed of the push-pull module is reduced at the zero-crossing moment, thereby controlling the IGBT to open slowly. This can fully utilize the advantage of the lowest energy at this time, avoid the occurrence of high conduction voltage and high conduction current, and thus reduce the risk of gates and opening noise. In addition, at the non-zero-crossing moment, the startup speed of the push-pull module is also adjusted. By increasing the startup speed of the push-pull module, the energy loss generated when the IGBT starts can be reduced, further optimizing the operation of the IGBT drive circuit, and ensuring the safety of the induction cooker and the user experience.

[0056] As an embodiment of the present invention, the push-pull module includes a switch element Q1, a switch element Q3, a capacitor C2, a resistor R2, a resistor R6, a resistor R9, a resistor R12, a resistor R13, a capacitor C2 and a Zener diode ZD1, and the driving module includes a resistor R3, a resistor R8, a resistor R10, a resistor R11, a switch element Q4 and a Zener diode ZD2.

[0057] The drive signal input terminal is connected to one end of the resistor R10, the other end of the resistor R10 is connected to the base of the switch element Q4, and the other end of the resistor R10 is also connected to the drive power supply VCC through the resistor R8, the emitter of the switch element Q4 is grounded, and a resistor R11 and a voltage zener diode ZD2 are also connected in parallel between the emitter of the switch element Q4 and the other end of the resistor R10. The collector of the switch element Q4 is simultaneously connected to the bases of the switch element Q1 and the switch element Q3, and the collector of the switch element Q4 is also connected to the drive power supply VCC through the resistor R3.

[0058] The base of the switch element Q1 is connected to the base of the switch element Q3, and the emitter of the switch element Q1 is connected to the emitter of the switch element, and the collector of the switch element Q1 is also connected to the driving power supply VCC through the resistor R2. The collector of the switch element Q3 is grounded through the resistor R13, and the base of the switch element Q3 is also grounded in sequence through the capacitor C2 and the resistor R12 connected in series. One end of the resistor R6 is connected to the emitters of the switch element Q1 and the switch element Q3 at the same time, and the other end of the resistor R6 is connected to the base of the IGBT. The resistor R9 and the voltage regulator diode ZD1 are connected in parallel to the base and emitter of the IGBT.

[0059] As an embodiment of the present invention, when the AC zero-crossing signal is at the zero-crossing moment, the regulating module is turned off to reduce the opening speed of the push-pull module at the zero-crossing moment;

[0060] When the AC zero-crossing signal is at a non-zero-crossing moment, the regulating module is enabled to increase the opening speed of the push-pull module at the non-zero-crossing moment.

[0061] The opening speed of the push-pull module is adjusted by controlling the opening and closing state of the regulating module. When the AC zero-crossing signal shows the zero-crossing moment, the voltage applied to the regulating module should be in a low-level state. At this time, the regulating module will be turned off, and the voltage or current applied to the input end of the push-pull module will change accordingly, thereby reducing the opening speed of the push-pull module and slowing down the conduction of the IGBT. When the AC zero-crossing signal shows a non-zero-crossing moment, the regulating module is in a normal operating state, thereby increasing the opening speed of the push-pull module and speeding up the conduction of the IGBT.

[0062] Specifically, in this embodiment, when the adjustment module is enabled, the comparison diagram of the driving signal and the signal applied to the IGBT base to drive the IGBT is as follows: Figure 2 As shown;

[0063] In this embodiment, when the regulating module is turned off, the driving signal and the signal applied to the IGBT base to drive the IGBT are compared as shown in the figure below: Figure 3 shown.

[0064] Preferably, the regulating module is set as a current regulating module, and the current regulating module regulates the current at the input end of the push-pull module according to the AC zero-crossing signal, and directly controls the opening speed of the push-pull module by regulating the current at the input end of the push-pull module.

[0065] Furthermore, the current regulation module includes a driving speed regulation circuit,

[0066] The driving speed regulating circuit is closed at the zero-crossing moment according to the AC zero-crossing signal to reduce the current at the input end of the push-pull module;

[0067] The driving speed regulating circuit is enabled at a non-zero point according to the AC zero-crossing signal to increase the current at the input end of the push-pull module.

[0068] The overall circuit diagram of an IGBT driving circuit according to an embodiment of the present invention is as follows: Figure 4 shown.

[0069] Specifically, Figure 4 As shown, the driving speed regulation circuit includes a resistor R1 and a switch element Q2, wherein one end of the resistor R1 is connected to the driving module, that is, one end of the resistor R1 is connected to the base of the switch element Q1 and the switch element Q3 through the resistor R3, the other end of the resistor R1 is connected to the collector of the switch element Q2, the emitter of the switch element Q2 is connected to the switch element Q1 and the switch element Q3, and the base of the switch element Q2 is connected to the input end of the zero-crossing sampling module.

[0070] When the AC zero-crossing signal is at the zero-crossing moment, the voltage applied to the collector of the switch element Q2 will be between 0-0.7V, and the switch element Q2 will be turned off. After the switch element Q2 is turned off, the parallel relationship between the resistor R1 and the resistor R3 in the driving module will be changed, and the resistance value applied between the input end of the push-pull module and the driving power supply will increase, thereby reducing the current at the input end of the push-pull module. When the AC zero-crossing signal is at a non-zero point, the voltage on the switch element Q2 will rise, and the switch element Q2 will be turned on, and the resistor R1 will establish a parallel relationship with the resistor R3 in the driving module, so that the resistance value applied between the input end of the push-pull module and the driving power supply will decrease, thereby increasing the current at the input end of the push-pull module.

[0071] As a preferred embodiment of the present invention, the regulating module includes at least one current regulating element connected in series between the input end of the push-pull module and the output end of the zero-crossing sampling module.

[0072] The current regulating element increases the resistance of the regulating module at the zero-crossing moment according to the AC zero-crossing signal to reduce the current at the input end of the push-pull module;

[0073] The current regulating element reduces the resistance of the regulating module at a non-zero-crossing moment according to the AC zero-crossing signal to increase the current at the input end of the push-pull module.

[0074] The purpose of adjusting the current at the input end of the push-pull module is achieved by using a current regulating element, and the current at the input end of the push-pull module is not simply adjusted by controlling the on and off state of the regulating module. The current regulating element can adjust the current at the input end of the push-pull module within the adjustment range, and does not only include the two states of on and off.

[0075] Specifically, the current regulating element may be an element with linearly variable resistance, such as a potentiometer or a variable resistor, etc., and the resistance of the regulating module may be adjusted according to the time when the AC zero-crossing signal is located.

[0076] As an embodiment of the present invention, the zero-crossing sampling module includes a rectifier element and a voltage divider element connected in series in the zero-crossing sampling module. The alternating current is input into the voltage divider element through the rectifier element, and the zero-crossing sampling module outputs an alternating zero-crossing signal according to the voltage divided by the voltage divider element.

[0077] Specifically, Figure 4 As shown, the rectifying element includes a rectifying diode D1 and a rectifying diode D2, and the voltage dividing element includes a resistor R4 and a resistor R7. The positive electrode of the rectifying diode D1 is connected to the AC live wire, the positive electrode of the rectifying diode D2 is connected to the AC neutral wire, the negative electrode of the rectifying diode D1 and the negative electrode of the rectifying diode D2 are simultaneously connected to one end of the resistor R4, and the other end of the resistor R4 is grounded through the resistor R7.

[0078] In order to ensure the detection effect of the zero-crossing sampling module, the accurate output of the AC zero-crossing signal and the safe operation of the adjustment module, the zero-crossing sampling module is also provided with a filter capacitor C1 and a current limiting resistor R5. The filter capacitor C1 is connected in parallel with the resistor R7. One end of the current limiting resistor R5 is connected between the resistor R4 and the resistor R7, and the other end of the current limiting resistor R5 is connected to the input end of the adjustment module, that is, the other end of the current limiting resistor R5 is connected to the base of the switching element Q2.

[0079] After being rectified by the rectifier diodes D1 and D2, the AC power is converted into DC power, and then divided by the resistors R4 and R7 to form a voltage of 0-5V. At the zero-crossing moment of the AC power, the divided voltage generated by the resistors R4 and R7 is reduced to the range of 0-0.7V, and the base voltage of the switch element Q2 is lower than the turn-on voltage, and the switch element Q2 will be turned off accordingly. At the non-zero-crossing moment of the AC power, the base voltage of the switch element Q2 will rise, and the switch element Q2 will be turned on again. The voltage characteristics of the AC power at the zero-crossing moment are used to realize the control of the regulation module.

[0080] As a preferred embodiment of the present invention, the zero-crossing sampling module includes a voltage detection element. The zero-crossing sampling module detects the zero-crossing moment of the alternating current through the voltage detection element and generates a corresponding alternating current zero-crossing signal.

[0081] In an AC circuit, the voltage changes with time in a sinusoidal wave. When the waveform changes from a positive half-cycle to a negative half-cycle or from a negative half-cycle to a positive half-cycle, the point passing through the x-coordinate is the zero-crossing point. Therefore, the voltage of the AC power is 0V at the zero-crossing moment, and the voltage detection element can be used to detect the voltage of the AC power, thereby realizing the detection of the zero-crossing moment.

[0082] Furthermore, the voltage detection element is any one of a zero-crossing detection chip, an optocoupler zero-crossing sampling module, or a buck regulator zero-crossing sampling module.

[0083] The zero-crossing detection chip directly integrates the zero-crossing detection function. By inputting the AC signal into the zero-crossing detection chip, the zero-crossing detection result can be directly output.

[0084] The optocoupler zero-crossing sampling module realizes zero-crossing detection by using two optocouplers connected in reverse parallel. After the alternating current is input into the optocoupler zero-crossing sampling module, since the two optocouplers are connected in reverse parallel, the two optocouplers are turned on in turn in the positive and negative half-cycles of the alternating current. When the alternating current is at a non-zero point, only one optocoupler is turned on. At this time, the optocoupler zero-crossing sampling module will output a low level. When the alternating current is at zero point, both optocouplers are not turned on. The optocoupler zero-crossing sampling module will output a high level, thereby distinguishing between the zero-crossing moment and the non-zero-crossing moment.

[0085] The buck regulator tube zero-crossing sampling module is similar to the principle of zero-crossing detection of the optocoupler zero-crossing sampling module, and can first step down the AC power, and then implement zero-crossing detection based on the conduction state of two reverse-parallel regulator tubes.

[0086] As a preferred embodiment of the present invention, it also includes a control signal input terminal 7 of the regulating module, and the control signal input terminal receives an external control signal to close the regulating module at the zero-crossing moment of the alternating current.

[0087] An external control signal can be formulated based on the detection result of the zero-crossing moment of the alternating current. At the zero-crossing moment of the alternating current, an external control signal is generated and input into the control signal input terminal. After receiving the external control signal, the regulating module will shut down automatically, which can also achieve the purpose of shutting down the regulating module at the zero-crossing moment.

[0088] In addition, the present invention also provides an electromagnetic cooking appliance, including a main control circuit for controlling the operation of the electromagnetic cooking appliance, the cooking appliance including a first power working mode and a second power working mode, the power of the second working mode is greater than the power of the first working mode, and the power of the first power working mode is not greater than 600 watts, the main control circuit includes an IGBT driving circuit in any of the above embodiments, so that the first power working mode and the second power working mode are both continuous heating modes. The IGBT driving circuit is integrated into the main control circuit to improve its convenience of use and reduce its cost, and the main control circuit, through the IGBT driving circuit in the utility model, enables the electromagnetic cooking appliance to achieve continuous heating cooking regardless of whether it is in the second working mode with a larger power or the first working mode with a smaller power, especially in the first working mode with a smaller power, compared with the intermittent heating mode adopted in the prior art, the use experience is greatly optimized, and at the same time, the voltage and current at the moment of IGBT conduction are reduced, thereby ensuring the service life of the electromagnetic cooking appliance.

[0089] The above-described embodiment is only a preferred solution of the present invention and does not limit the present invention in any form. There are other variations and modifications without exceeding the technical solution described in the claims.

Claims

1. An IGBT driving circuit for electromagnetic heating, comprising: A driving signal input terminal, used to receive a driving signal for driving the IGBT; Push-pull module, used to control the conduction state of IGBT; A driving module connected to a driving signal input terminal to obtain a driving signal to form a driving working signal for driving the push-pull module to work; A driving power supply, used to supply power to the IGBT driving circuit; It is characterized by further comprising an adjustment module and a zero-crossing sampling module. The output end of the regulating module is connected to the driving module, and the input end is connected to the output end of the zero-crossing sampling module. The regulating module adjusts the driving working signal of the driving module according to the AC zero-crossing signal obtained by the zero-crossing sampling module.

2. An IGBT driving circuit for electromagnetic heating according to claim 1, characterized in that: When the AC zero-crossing signal is at the zero-crossing moment, the regulating module is turned off to reduce the opening speed of the push-pull module at the zero-crossing moment; When the AC zero-crossing signal is at a non-zero-crossing moment, the regulating module is enabled to increase the opening speed of the push-pull module at the non-zero-crossing moment.

3. The IGBT driving circuit for electromagnetic heating according to claim 2, characterized in that: The regulating module is a current regulating module, and the current regulating module regulates the current at the input end of the push-pull module according to the AC zero-crossing signal.

4. The IGBT driving circuit for electromagnetic heating according to claim 3, characterized in that: The current regulation module includes a driving speed regulation circuit, The driving speed regulating circuit is closed at the zero-crossing moment according to the AC zero-crossing signal to reduce the current at the input end of the push-pull module; The driving speed regulating circuit is enabled at a non-zero point according to the AC zero-crossing signal to increase the current at the input end of the push-pull module.

5. The IGBT driving circuit for electromagnetic heating according to claim 1, characterized in that: The regulating module includes at least one current regulating element connected in series between the input end of the push-pull module and the output end of the zero-crossing sampling module. The current regulating element increases the resistance of the regulating module at the zero-crossing moment according to the AC zero-crossing signal to reduce the current at the input end of the push-pull module; The current regulating element reduces the resistance of the regulating module at a non-zero-crossing moment according to the AC zero-crossing signal to increase the current at the input end of the push-pull module.

6. The electromagnetic heating IGBT driving circuit according to claim 1, characterized in that: The zero-crossing sampling module includes a voltage detection element. The zero-crossing sampling module detects the zero-crossing moment of the alternating current through the voltage detection element and generates a corresponding alternating current zero-crossing signal.

7. The IGBT driving circuit for electromagnetic heating according to claim 6, characterized in that: The voltage detection element is any one of a zero-crossing detection chip, an optocoupler zero-crossing sampling module, or a buck regulator tube zero-crossing sampling module.

8. The electromagnetic heating IGBT driving circuit according to claim 1, characterized in that: The zero-crossing sampling module includes a rectifier element and a voltage divider element connected in series in the zero-crossing sampling module. The alternating current is input into the voltage divider element through the rectifier element, and the zero-crossing sampling module outputs an alternating zero-crossing signal according to the voltage divided by the voltage divider element.

9. The IGBT driving circuit for electromagnetic heating according to claim 1, characterized in that: It also includes a control signal input end of the regulating module, which receives an external control signal to close the regulating module at the zero-crossing moment of the alternating current.

10. An electromagnetic cooking appliance, comprising a main control circuit for controlling the operation of the electromagnetic cooking appliance, the cooking appliance comprising a first power operating mode and a second power operating mode, the power of the second operating mode being greater than the power of the first operating mode, and the power of the first power operating mode being no greater than 600 watts, characterized in that: The main control circuit is provided with the IGBT driving circuit according to any one of claims 1 to 9, so that the first power operating mode and the second power operating mode are both continuous heating modes.

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