CN211557529U - Electromagnetic heating circuit and electromagnetic oven - Google Patents

Abstract

The embodiment of the utility model provides an electromagnetic heating circuit and electromagnetism stove, include: controller, resonant circuit and drive circuit, the controller includes: the control circuit is respectively connected with the comparator and the output circuit; the non-inverting input end and the inverting input end of the comparator are respectively connected with the resonant circuit, and the output end of the comparator is connected with the output circuit; the driving circuit is respectively connected with the output circuit and the resonant circuit; the control circuit is used for acquiring the output voltage of the output circuit in a preset time period, and controlling the change of the voltage value input by the comparator when the output voltage of the output circuit in the preset time period is constant, so that the output voltage of the output circuit is periodically changed. For enabling a fast restart operation of the resonant circuit.

Description

Electromagnetic heating circuit and electromagnetic oven

Technical Field

The embodiment of the utility model provides an electromagnetic heating circuit and electromagnetism stove are related to electromagnetism stove technical field especially.

Background

The induction cooker control circuit is arranged in the induction cooker, and the cookware can be heated in the working process of the induction cooker control circuit.

At present, an induction cooker control circuit includes a resonant circuit and a comparator, when a voltage value at an input end of the comparator changes, a voltage value output by the comparator reverses, for example, from a high level to a low level, or from the low level to the high level, and in a process of reversing the voltage value output by the comparator, an alternating current commercial power can be used for charging the resonant circuit and the resonant circuit resonates, so that a cooker is heated by the resonant circuit. In practical application, because the zero crossing point exists after the alternating current mains supply enters the induction cooker through rectification treatment, when the zero crossing point is long, the voltage value at the input end of the comparator is not changed for a long time, so that the alternating current mains supply stops charging the resonant circuit, the resonant circuit stops resonating, and the resonant circuit stops heating the cookware.

SUMMERY OF THE UTILITY MODEL

An embodiment of the utility model provides an electromagnetic heating circuit and electromagnetism stove for make the quick restart work of resonant circuit.

In a first aspect, the present application provides an electromagnetic heating circuit comprising: a controller 101, a resonant circuit (102) and a drive circuit (103), the controller 101 comprising: a control circuit 111, a comparator 112, and an output circuit 113, wherein,

the control circuit 111 is connected to the comparator 112 and the output circuit 113, respectively;

the non-inverting input end and the inverting input end of the comparator 112 are respectively connected with the resonance circuit (102), and the output end of the comparator 112 is connected with the output circuit 113;

the driving circuit (103) is respectively connected with the output circuit 113 and the resonance circuit (102);

the control circuit 111 is configured to obtain an output voltage of the output circuit 113 in a preset time period, and control the voltage value input by the comparator 112 to change when the output voltage of the output circuit 113 in the preset time period is constant, so that the output voltage of the output circuit 113 changes periodically.

In one possible design, the controller 101 further includes: a first port 114 and a second port 115, wherein,

the same-direction input end of the comparator 112 is connected with the resonant circuit (102) through the first port 114;

the inverting input of the comparator 112 is connected to the resonant circuit (102) via the second port 115.

In another possible design, the control circuit 111 includes: an input control circuit 116 and an output control circuit (117), wherein,

the input control circuit 116 and the output control circuit (117) are respectively connected to the first port 114;

wherein the input control circuit 116 and the output control circuit (117) are configured to set the state of the first port 114 at different times, the input control circuit 116 is configured to set the state of the first port 114 to an input state, and the output control circuit (117) is configured to set the state of the first port 114 to an output state.

In another possible design, the output circuit 113 includes: the programmable pulse generator PPG controls an output circuit 118 and a status reading circuit 119, wherein,

the PPG control output circuit 118 is connected to the status reading circuit 119 and the control circuit 111 respectively;

the state reading circuit 119 is configured to read an output voltage of the PPG control output circuit 118, and send the output voltage of the PPG control output circuit 118 to the control circuit 111.

In another possible design, the resonant circuit (102) comprises: a resonance module 210 and an insulated gate bipolar transistor IGBT module 211, wherein,

the resonance module 210 is respectively connected with the controller 101 and the IGBT module 211, and the IGBT module 211 is connected with the driving circuit (103).

In another possible design, the resonance module 210 includes: a resonating device 212 and a detection device 213, wherein,

the resonant device 212 is connected to the detection device 213 and the IGBT module 211, respectively, and the detection device 213 is further connected to the controller 101.

In another possible design, the resonating device 212 includes: a first inductor and a first capacitor, wherein,

the first inductor and the first capacitor are connected in parallel, and the first inductor and the first capacitor which are connected in parallel have a first parallel junction and a second parallel junction;

the first parallel connection points are respectively connected with the IGBT module 211 and the detection device 213;

the second parallel connection point is connected to the detection device 213.

In another possible design, the detection device 213 includes: a first resistor, a second resistor, a third resistor, and a fourth resistor, wherein,

one end of the first resistor is connected with the second parallel connection point, the other end of the first resistor is connected with one end of the second resistor, and the other end of the second resistor is grounded;

one end of the third resistor is connected with the first parallel connection point, the other end of the third resistor is connected with one end of the fourth resistor, and the other end of the fourth resistor is grounded;

the non-inverting input terminal of the comparator 112 is connected to the connection point of the first resistor and the second resistor through the input control circuit 116 of the control circuit 111, and the inverting input terminal of the comparator 112 is connected to the connection point of the third resistor and the fourth resistor.

In another possible design, the IGBT module 211 includes: an IGBT, a fifth resistor, a sixth resistor and a diode, wherein,

one end of the fifth resistor is connected with the gate pole of the IGBT and one end of the sixth resistor respectively, and the other end of the fifth resistor is connected with the drive circuit (103) and the cathode of the diode respectively;

and the collector of the IGBT is connected with the resonance module, and the emitter of the IGBT, the other end of the sixth resistor and the anode of the diode are grounded.

In another possible embodiment, the driver circuit (103) comprises: a first power supply, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, a first triode, a second triode, and a third triode,

the first power supply is connected with the base electrode of the first triode sequentially through the seventh resistor and the eighth resistor;

the first power supply is also respectively connected with the collector of the first triode, the base of the second triode and the base of the third triode through the ninth resistor;

the first power supply is also connected with a collector of the second triode, an emitter of the second triode is connected with an emission set of the third triode through a tenth resistor, and the collector of the third triode is grounded;

the controller 101 is connected to a connection point of the seventh resistor and the eighth resistor.

In a second aspect, the present application provides an induction cooker comprising the electromagnetic heating circuit of any one of the above first aspects.

The application provides an electromagnetic heating circuit and electromagnetism stove includes: the controller 101 comprises a controller 101, a resonant circuit (102) and a driving circuit (103), wherein the controller 101 comprises a control circuit 111, a comparator 112 and an output circuit 113, wherein the control circuit 111 is respectively connected with the comparator 112 and the output circuit 113; the non-inverting input end and the inverting input end of the comparator 112 are connected with the resonance circuit (102), and the output end of the comparator 112 is connected with the output circuit 113; the driving circuit (103) is respectively connected with the output circuit 113 and the resonance circuit (102); the control circuit 111 is configured to obtain an output voltage of the output circuit 113 in a preset time period, and control the voltage value input by the comparator 112 to change when the output voltage of the output circuit 113 in the preset time period is constant, so that the output voltage of the output circuit 113 changes periodically. In the above process, when the output voltage of the output circuit 113 is constant in the preset time period, the control circuit 111 controls the voltage value input by the comparator 112 to change, so that the resonant circuit (102) is restarted quickly, and the user experience is improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without inventive labor.

Fig. 1 is a first schematic structural diagram of an electromagnetic heating circuit provided in the present application;

fig. 2 is a schematic structural diagram ii of an electromagnetic heating circuit according to an embodiment of the present application;

fig. 3 is a schematic structural diagram three of an electromagnetic heating circuit provided in the embodiment of the present application;

fig. 4 is a schematic structural diagram of an electromagnetic heating circuit according to an embodiment of the present application;

fig. 5 is a time domain waveform diagram of the ac mains provided by the present application;

reference numerals:

100-an electromagnetic heating circuit; 101-a controller;

102-a resonant circuit; 103-a drive circuit;

111-a control circuit; 112-a comparator;

113-an output circuit; 114 — first port;

115 — a second port; 116 — an input control circuit;

117-output control circuit; 118-PPG control output circuit;

119-a state reading circuit; 210-a resonant module;

211-insulated gate bipolar transistor, IGBT, module; 212 — a resonant device;

213 — detection device.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

Fig. 1 is a first schematic structural diagram of an electromagnetic heating circuit provided in the present application. As shown in fig. 1, the electromagnetic heating circuit includes: controller 101, resonant circuit 102 and drive circuit 103, controller 101 includes: a control circuit 111, a comparator 112, and an output circuit 113, wherein,

the control circuit 111 is connected to the comparator 112 and the output circuit 113, respectively;

the non-inverting input end and the inverting input end of the comparator 112 are respectively connected with the resonance circuit (102), and the output end of the comparator 112 is connected with the output circuit 113;

the driving circuit 103 is connected to the output circuit 113 and the resonance circuit 102, respectively;

the control circuit 111 is configured to obtain an output voltage of the output circuit 113 in a preset time period, and control the voltage value input by the comparator 112 to change when the output voltage of the output circuit 113 in the preset time period is constant, so that the output voltage of the output circuit 113 changes periodically.

The controller 101 is a Micro Controller Unit (MCU).

In the present application, the resonant circuit 102 may be connected to the ac mains. During the operation of the electromagnetic heating circuit, the ac mains 1 charges the resonant circuit 102, so that the resonant circuit 102 can resonate.

It should be noted that the ac mains has a time domain waveform diagram as shown in fig. 5, and zero-crossing points exist in the time domain waveform diagram of the ac mains.

When the electromagnetic heating circuit works in a non-zero-crossing point region, the electromagnetic heating circuit has the following working process:

the control circuit 111 controls the output voltage of the comparator 112 to change from a first low level to a first high level, and a rising edge trigger signal is formed in the change process from the first low level to the first high level; the output circuit 113 generates a second low level according to the rising edge trigger signal and transmits the second low level to the driving circuit 103; the driving circuit 103 generates a third high level according to the first low level and transmits the third high level to the resonance circuit (102); after receiving the third high level, the resonant circuit 102 obtains ac power from the ac mains 1, so as to charge the first inductor in the resonant circuit 102.

The control circuit 111 may obtain the output voltage of the output circuit 113, and when it is determined that the output voltage is at the second low level and the duration of the second low level is equal to the first preset duration, the control circuit 111 controls the output circuit 113 to generate the second high level and sends the second high level to the driving circuit 103; the driving circuit 103 stops sending the third high level to the resonant circuit 102 according to the second high level, the ac mains stops charging the first inductor in the resonant circuit 102, and the first inductor and the first capacitor in the resonant circuit 102 form resonance. During the resonance process, the first inductor charges the first capacitor, and after the charging is completed, the first capacitor discharges the first inductor.

The comparator 112 may detect a resonant voltage in the resonant circuit 102, when the comparator 112 determines that the resonant voltage has a minimum voltage value, the output voltage of the comparator 112 changes from a first low level to a first high level to form a rising edge trigger signal, the output circuit 113 outputs a second low level according to the rising edge trigger signal and sends the second low level to the driving circuit 103, and the driving circuit 103 generates a third high level according to the second low level, so that the resonant circuit 102 obtains ac mains from the ac mains 1 to complete charging the first inductor in the resonant circuit 102.

It should be noted that, the process of charging the first inductor by the ac mains supply and the process of resonating the first inductor and the first capacitor can enable the electromagnetic heating circuit to generate heat.

Further, the control circuit 111 includes: the control bus 121, the processor 122, the input control circuit 116 and the output control circuit 117 refer to the embodiment of fig. 2 for the connection relationship among the control bus 121, the processor 122, the input control circuit 116 and the output control circuit 117.

In this application, the processor 122 may control the input control circuit 116 to set the state of the non-inverting input terminal of the comparator 112 to the input state, and the processor 122 may also control the output control circuit 117 to set the state of the non-inverting input terminal of the comparator 112 to the output state.

Further, the present application provides that when the alternating current mains supply has a zero crossing point for a long period of time, the electromagnetic heating circuit has the following working process:

after the processor 122 determines that the output voltage of the output circuit 113 is constant within the preset time period, i.e., the output voltage does not flip over for a long time through the control bus 121, it may be determined that the resonance process of the resonance circuit (102) is stopped, at which time the processor 122 controls the output control circuit 117 to set the non-inverting input terminal of the comparator 112 to the output state and input a low level to the non-inverting input terminal, the voltage value of the low level being smaller than the voltage value of the level of the inverting input terminal of the comparator 112, at which time the output terminal of the comparator 112 outputs the first low level.

Next, the processor 122 controls the input control circuit 116 to set the non-inverting input terminal of the comparator 112 to the input state, where the voltage value of the level of the non-inverting input terminal is greater than the voltage value of the level of the inverting input terminal of the comparator 112, and where the output terminal of the comparator 112 outputs the first high level.

In the above process, in the process that the comparator 112 changes from outputting the first low level to outputting the first high level, the rising edge trigger signal is formed, so that the output circuit 113 generates the second low level according to the rising edge trigger signal, thereby realizing charging of the first inductor. When the duration of the second low level is equal to the first preset duration, the control circuit 111 controls the output circuit 113 to generate a second high level and sends the second high level to the driving circuit 103; the driving circuit 103 stops sending the third high level to the resonant circuit 102 according to the second high level, the ac mains stops charging the first inductor in the resonant circuit 102, and the first inductor and the first capacitor in the resonant circuit 102 form resonance, thereby restarting the periodic working process of the resonant circuit 102.

Optionally, the preset time period may be 2 resonance cycles, that is, 100 microseconds, or 3 resonance cycles, and the like, and specifically, the size of the preset time period is not limited in this application.

Different from the prior art, in the prior art, whether the resonance circuit stops the resonance process is judged according to the complete machine current of the induction cooker, after the resonance process is determined to stop, the coupling state of the cookware is detected, and after the cookware is determined to be successfully coupled, the periodic working process of the resonance circuit is restarted, so that the restarting process is long in time, and the user experience is further reduced. In the application, when the processor determines that the output voltage of the output circuit is constant in a preset time period, the processor controls the comparator to output a first low level, so that the output circuit outputs a second low level, and when the duration of the second low level is equal to the first preset duration, the output circuit is controlled to output a second low level, so that the resonant circuit can be restarted quickly, the time spent for restarting the operation can be usually 200 microseconds, and the user experience is improved.

The application provides an electromagnetic heating circuit includes: the controller 101, the resonant circuit (102) and the driving circuit 103, wherein the controller 101 comprises a control circuit 111, a comparator 112 and an output circuit 113, wherein the control circuit 111 is respectively connected with the comparator 112 and the output circuit 113; the non-inverting input end and the inverting input end of the comparator 112 are connected with the resonant circuit 102, and the output end of the comparator 112 is connected with the output circuit 113; the driving circuit 103 is connected to the output circuit 113 and the resonance circuit 102, respectively; the control circuit 111 is configured to obtain an output voltage of the output circuit 113 in a preset time period, and control the voltage value input by the comparator 112 to change when the output voltage of the output circuit 113 in the preset time period is constant, so that the output voltage of the output circuit 113 changes periodically. In the above process, when the output voltage of the output circuit 113 is constant in the preset time period, the control circuit 111 controls the voltage value input by the comparator 112 to change, so that the resonant circuit 102 is restarted quickly, and the user experience is improved.

The technical means shown in the present application will be described in detail below with reference to specific examples. It should be noted that the following embodiments may be combined with each other, and the description of the same or similar contents in different embodiments is not repeated.

Fig. 2 is a schematic structural diagram of an electromagnetic heating circuit according to an embodiment of the present application. On the basis of fig. 1, as shown in fig. 2, the controller 101 further includes: a first port 114 and a second port 115, wherein,

the unidirectional input of the comparator 112 is connected to the resonant circuit 102 via a first port 114;

the inverting input of the comparator 112 is connected to the resonant circuit 102 via a second port 115.

In one possible design, the control circuit 111 includes: an input control circuit 116 and an output control circuit 117, wherein,

the input control circuit 116 and the output control circuit 117 are connected to the first port 114, respectively;

the input control circuit 116 and the output control circuit 117 are configured to set the state of the first port 114 at different times, the input control circuit 116 is configured to set the state of the first port 114 to an input state, and the output control circuit 117 is configured to set the state of the first port 114 to an output state.

Specifically, the controller 101 is also connected to a power supply 120, wherein the power supply 120 is used for inputting 5 volts to the controller 101.

The input control circuit 116 and the output control circuit 117 are also connected to the processor, respectively.

Further, the processor 122, the input control circuit 116, and the output control circuit 117 in the controller 101 are connected to the control bus 121, respectively.

In another possible design, output circuit 113 includes: the programmable pulse generator PPG controls an output circuit 118 and a status reading circuit 119, wherein,

the PPG control output circuit 118 is connected with the state reading circuit 119 and the control circuit 111 respectively;

the state reading circuit 119 is configured to read an output voltage of the PPG control output circuit 118, and send the output voltage of the PPG control output circuit 118 to the control circuit 111.

Specifically, the status reading circuit 119 is connected to the control bus 121.

It should be noted that the electromagnetic heating circuit may further include a rectifying circuit 410, wherein the ac mains 1 is connected to the rectifying circuit 410, and is configured to process 220 v ac output by the ac mains 1 into 311 v dc including an ac component, and input 311 v dc to the resonant circuit 102.

Optionally, a filter capacitor 411 may be further included in the electromagnetic heating circuit, wherein the filter capacitor 411 is configured to filter an alternating current component in the direct current.

Further, when there is a zero crossing point of a long period in the ac mains, the controller 101 has the following operation:

the state reading circuit 119 reads an output voltage of the PPG control output circuit 118, and uploads the output voltage of the PPG control output circuit 118 to the control bus 121, the processor 122 acquires the output voltage of the PPG control output circuit 118 in a preset time period from the control bus 121, and determines whether the output voltage in the preset time period is constant, if it is determined that the output voltage in the preset time period is constant, the processor 122 controls the output control circuit 117 to set the non-inverting input terminal of the comparator 112 to be in an output state, and meanwhile, the non-inverting input terminal is at a low level, the level value of the low level is smaller than the level value of the inverting input terminal of the comparator 112, and at this time, the comparator 112 outputs a first low level. Then, the processor 122 controls the input control circuit 116 to set the non-inverting input terminal of the comparator 112 to the input state, at which the level value of the non-inverting input terminal is greater than the level value of the inverting input terminal of the comparator 112, at which the output of the comparator 112 is at the first high level. In the above process, the comparator 112 forms a rising edge trigger signal in the process of outputting the first low level to the first high level, so as to realize the charging process of charging the first inductor in the resonant circuit 102.

On the basis of any of the above embodiments, the electromagnetic heating circuit provided in the present application is further described in detail with reference to fig. 3, specifically, refer to fig. 3.

Fig. 3 is a schematic structural diagram three of an electromagnetic heating circuit provided in the embodiment of the present application. On the basis of fig. 2, as shown in fig. 3, the resonant circuit 102 includes: a resonance module 210 and an insulated gate bipolar transistor IGBT module 211, wherein,

the resonant module 210 is connected to the controller 101 and the IGBT module 211, respectively, and the IGBT module 211 is connected to the driving circuit 103.

In one possible design, the resonance module 102 includes: a resonating device 212 and a detection device 213, wherein,

the resonant device 212 is connected to the detection device 213 and the IGBT module 211, respectively, and the detection device 213 is further connected to the controller 101.

In one possible design, resonating device 212 includes: a first inductor 214 and a first capacitor 215, wherein,

the first inductor 214 and the first capacitor 215 are connected in parallel, and the first inductor 214 and the first capacitor 215 connected in parallel have a first parallel connection point 216 and a second parallel connection point 217;

the first parallel connection point 216 is connected to the IGBT module 211 and the detection device 213, respectively;

the second parallel junction 217 is connected to the detection device 213.

In one possible design, the detection device 213 includes: a first resistor 218, a second resistor 219, a third resistor 220, and a fourth resistor 221, wherein,

one end of the first resistor 218 is connected to the second parallel connection point, the other end of the first resistor 218 is connected to one end of the second resistor 219, and the other end of the second resistor 219 is grounded;

one end of the third resistor 220 is connected to the first parallel connection point, the other end of the third resistor 220 is connected to one end of the fourth resistor 221, and the other end of the fourth resistor 221 is grounded;

the non-inverting input terminal of the comparator 112 is connected to the connection point of the first resistor 218 and the second resistor 219 via the input control circuit 116 in the control circuit 111, and the inverting input terminal of the comparator 112 is connected to the connection point of the third resistor 220 and the fourth resistor 221.

In one possible design, the IGBT module 211 includes: an IGBT 222, a fifth resistor 223, a sixth resistor 224, and a diode 225, wherein,

one end of the fifth resistor 223 is connected to the gate of the IGBT 222 and one end of the sixth resistor 224, respectively, and the other end of the fifth resistor 223 is connected to the drive circuit 103 and the negative electrode of the diode 225, respectively;

the collector of the IGBT 222 is connected to the resonant module 210, and the emitter of the IGBT 222, the other end of the sixth resistor 224, and the anode of the diode 225 are grounded.

The first resistor 218, the second resistor 219, the third resistor 220, and the fourth resistor 221, the fifth resistor 223, and the sixth resistor 224 are resistors with fixed resistance values. Diode 225 is a zener diode. The diode 225 is used to stabilize the voltage between the gate and emitter of the IGBT 222.

The resonant circuit 102 provided by the present application has the following working processes: the driving circuit 103 inputs a second high level to the IGBT module 211, and the second high level flows to the gate of the IGBT 222 through the fifth resistor 223, so that the IGBT 222 is turned on, when the IGBT 222 is turned on, the ac mains 1 charges the first inductor 214, the state reading circuit 119 reads the first low voltage output by the PPG control output circuit 118, when the duration of the first low voltage is equal to the first preset duration, the processor 122 controls the PPG control output circuit 118 to output a first high level, so that the driving circuit 103 stops inputting the second high level to the IGBT module 211 according to the first high level, and at this time, the IGBT 222 is turned off, the first inductor 214 and the first capacitor 215 resonate, and when the non-inverting input terminal and the inverting input terminal of the comparator 112 determine that the resonant voltage in the resonant circuit 102 reaches the minimum value based on the terminal voltages of the first resistor 218 and the third resistor 220, comparator 112 controls the first low level output by PPG control output circuit 118.

On the basis of any of the above embodiments, the following describes in detail a structural schematic of the electromagnetic heating circuit provided in the present application with reference to fig. 4, and specifically, refer to fig. 4.

Fig. 4 is a schematic structural diagram of an electromagnetic heating circuit according to an embodiment of the present application. In addition to fig. 3, as shown in fig. 4, the driving circuit 103 in the electromagnetic heating circuit includes: a first power supply 310, a seventh resistor 311, an eighth resistor 312, a ninth resistor 313, a tenth resistor 314, a first transistor 315, a second transistor 316, and a third transistor 317, wherein,

the first power supply 310 is connected with the base of the first triode 315 through the seventh resistor 311 and the eighth resistor 312 in sequence;

the first power supply 310 is further connected to the collector of the first transistor 315, the base of the second transistor 316, and the base of the third transistor 317 through a ninth resistor 313;

the first power supply 310 is further connected to a collector of a second transistor 316, an emitter of the second transistor 316 is connected to an emitter of a third transistor through a tenth resistor 314, and the collector of the third transistor is grounded;

the controller 101 is connected to a connection point of the seventh resistor and the eighth resistor.

Specifically, the first power supply 310 is configured to output a voltage of 18 volts.

Optionally, the driving circuit 103 further includes: and one end of the second capacitor 318 is connected with the base of the third transistor 317, and one end of the second capacitor 318 is grounded.

It should be noted that the first transistor 315 and the second transistor 316 are NPN transistors, and the third transistor 317 is a PNP transistor.

Further, the driving circuit 103 has the following operation processes: when the PPG control output circuit 118 outputs the second low level, the first transistor 315 is turned off, the bases of the second transistor 316 and the third transistor 317 have a high level, the second transistor 316 is turned on, the third transistor 317 is turned off, and the first power supply 310 may transmit the third high level voltage value of 18 v to the resonant circuit 102. When the PPG control output circuit 118 outputs the second high level, the first transistor 315 is turned on, the bases of the second transistor 316 and the third transistor 317 have low levels, the second transistor 316 is turned off, the third transistor 317 is turned on, and the first power supply 310 cannot transmit the third high level to the resonant circuit 102.

The application also provides an induction cooker comprising the electromagnetic heating circuit provided by any of the above embodiments.

Fig. 5 is a time domain waveform diagram of the ac mains provided by the present application. Referring to fig. 5, the time domain wave of the ac mains is a sine wave having a zero crossing point.

At the zero crossing point, the programmable pulse generator PPG controls the output voltage of the output circuit 118 to be unchanged, i.e. there is no periodic change.

When the output voltage of the programmable pulse generator PPG control output circuit 118 does not change, the collector voltage value of the IGBT is 0, that is, the resonant circuit 102 is considered to stop operating.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the embodiments of the present invention, and not to limit the same; although embodiments of the present invention have been described in detail with reference to the foregoing embodiments, those skilled in the art will understand that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the embodiments of the present invention.

Claims (11)

1. An electromagnetic heating circuit, comprising: a controller (101), a resonant circuit (102) and a drive circuit (103), the controller (101) comprising: a control circuit (111), a comparator (112) and an output circuit (113), wherein,

the control circuit (111) is respectively connected with the comparator (112) and the output circuit (113);

the non-inverting input end and the inverting input end of the comparator (112) are respectively connected with the resonance circuit (102), and the output end of the comparator (112) is connected with the output circuit (113);

the driving circuit (103) is respectively connected with the output circuit (113) and the resonance circuit (102);

the control circuit (111) is used for acquiring the output voltage of the output circuit (113) in a preset time period, and when the output voltage of the output circuit (113) in the preset time period is constant, the control circuit controls the voltage value input by the comparator (112) to change so as to enable the output voltage of the output circuit (113) to change periodically.

2. The electromagnetic heating circuit according to claim 1, wherein the controller (101) further comprises: a first port (114) and a second port (115), wherein,

the same-direction input end of the comparator (112) is connected with the resonant circuit (102) through the first port (114);

the inverting input of the comparator (112) is connected to the resonant circuit (102) via the second port (115).

3. The electromagnetic heating circuit according to claim 2, characterized in that the control circuit (111) comprises: an input control circuit (116) and an output control circuit (117), wherein,

the input control circuit (116) and the output control circuit (117) are respectively connected with the first port (114);

wherein the input control circuit (116) and the output control circuit (117) are configured to set the state of the first port (114) at different times, the input control circuit (116) is configured to set the state of the first port (114) to an input state, and the output control circuit (117) is configured to set the state of the first port (114) to an output state.

4. The electromagnetic heating circuit according to any of claims 1-3, wherein the output circuit (113) comprises: a programmable pulse generator PPG controls an output circuit (118) and a status reading circuit (119), wherein,

the PPG control output circuit (118) is respectively connected with the state reading circuit (119) and the control circuit (111);

the state reading circuit (119) is used for reading the output voltage of the PPG control output circuit (118) and sending the output voltage of the PPG control output circuit (118) to the control circuit (111).

5. An electromagnetic heating circuit according to any of claims 1-3, characterized in that the resonance circuit (102) comprises: a resonance module (210) and an insulated gate bipolar transistor, IGBT, module (211), wherein,

the resonance module (210) is respectively connected with the controller (101) and the IGBT module (211), and the IGBT module (211) is connected with the drive circuit (103).

6. The electromagnetic heating circuit according to claim 5, characterized in that the resonance module (210) comprises: a resonator device (212) and a detection device (213), wherein,

the resonance device (212) is respectively connected with the detection device (213) and the IGBT module (211), and the detection device (213) is also connected with the controller (101).

7. An electromagnetic heating circuit according to claim 6, characterized in that the resonator device (212) comprises: a first inductor and a first capacitor, wherein,

the first inductor and the first capacitor are connected in parallel, and the first inductor and the first capacitor which are connected in parallel have a first parallel junction and a second parallel junction;

the first parallel connection points are respectively connected with the IGBT module (211) and the detection device (213);

the second parallel connection point is connected to the detection means (213).

8. The electromagnetic heating circuit according to claim 7, characterized in that the detection means (213) comprise: a first resistor, a second resistor, a third resistor, and a fourth resistor, wherein,

one end of the first resistor is connected with the second parallel connection point, the other end of the first resistor is connected with one end of the second resistor, and the other end of the second resistor is grounded;

one end of the third resistor is connected with the first parallel connection point, the other end of the third resistor is connected with one end of the fourth resistor, and the other end of the fourth resistor is grounded;

the non-inverting input end of the comparator (112) is connected with the connection point of the first resistor and the second resistor through an input control circuit (116) in the control circuit (111), and the inverting input end of the comparator (112) is connected with the connection point of the third resistor and the fourth resistor.

9. The electromagnetic heating circuit according to claim 5, characterized in that the IGBT module (211) comprises: an IGBT, a fifth resistor, a sixth resistor and a diode, wherein,

one end of the fifth resistor is connected with the gate pole of the IGBT and one end of the sixth resistor respectively, and the other end of the fifth resistor is connected with the drive circuit (103) and the cathode of the diode respectively;

and the collector of the IGBT is connected with the resonance module, and the emitter of the IGBT, the other end of the sixth resistor and the anode of the diode are grounded.

10. An electromagnetic heating circuit according to any of claims 1-3, characterized in that the drive circuit (103) comprises: a first power supply, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, a first triode, a second triode, and a third triode,

the first power supply is connected with the base electrode of the first triode sequentially through the seventh resistor and the eighth resistor;

the first power supply is also respectively connected with the collector of the first triode, the base of the second triode and the base of the third triode through the ninth resistor;

the first power supply is also connected with a collector of the second triode, an emitter of the second triode is connected with an emission set of the third triode through a tenth resistor, and the collector of the third triode is grounded;

the controller (101) is connected to a connection point of the seventh resistor and the eighth resistor.

11. An induction cooking hob, characterized in, that it comprises an electromagnetic heating circuit according to any one of the claims 1-10.

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