CN109982467A

CN109982467A - Electromagnetic heating circuit, electromagnetic heating utensil and current control process

Info

Publication number: CN109982467A
Application number: CN201811513750.3A
Authority: CN
Inventors: 孙鹏刚; 赵礼荣
Original assignee: Zhejiang Shaoxing Supor Domestic Electrical Appliance Co Ltd
Current assignee: Zhejiang Shaoxing Supor Domestic Electrical Appliance Co Ltd
Priority date: 2018-12-11
Filing date: 2018-12-11
Publication date: 2019-07-05

Abstract

The present invention provides a kind of electromagnetic heating circuit (100), electromagnetic heating utensil (10) and current control process.The electromagnetic heating circuit (100) includes microprocessing unit (101), level shifting circuit (102), waveform convertion circuit (103), push-pull circuit (104) and IGBT module (105).Wherein, first output end of microprocessing unit (101) is connect with level shifting circuit (102), the second output terminal of microprocessing unit (101) is connect with waveform convertion circuit (103), the input terminal of push-pull circuit (104) is connect with level shifting circuit (102) and waveform convertion circuit (103) respectively, the output end of push-pull circuit (104) is connect with the grid of IGBT module (105), the on or off that microprocessing unit (101) passes through control waveform convertion circuit (103), realize the transient current that IGBT module (105) are considerably reduced when the work of electromagnetic heating utensil (10) small-power, improve the working condition of IGBT module (105).

Description

Electromagnetic heating circuit, electromagnetic heating utensil and current control process

Technical field

The present invention relates to electromagentic furnace technology field more particularly to a kind of electromagnetic heating circuits, electromagnetic heating utensil and electric current Adjusting method.

Background technique

Electromagnetic heating circuit can use electromagnetic induction principle and convert electrical energy into thermal energy, treats heating equipment and is added Heat.Electromagnetic heating circuit application field is relatively broad, such as electric cooker, electric pressure cooker, soy bean milk making machine, coffee machine, blender are various It needs in the electromagnetic heating utensil of heating function.

In general, when electromagnetic heating utensil is in high-power heating, in existing electromagnetic heating circuit, in insulated gate bipolar When voltage zero-cross in the drain electrode of transistor (Insulated Gate Bipolar Transistor, IGBT) module, IGBT mould Block conducting, the electric current very little of IGBT module.However, when electromagnetic heating utensil is in low-power heating, existing electromagnetic heating electricity Lu Zhong, if IGBT module conducting, the electric current of IGBT module is larger in the case where the drain electrode of IGBT module still has certain voltage, The loss of IGBT module is easily caused, the device cost of electromagnetic heating utensil is improved.

Summary of the invention

The present invention provides a kind of electromagnetic heating circuit, electromagnetic heating utensil and current control process, to solve existing electromagnetism That the instantaneous drain-source electrode current of IGBT module is connected is excessive and make since electromagnetic heating utensil is under small-power state for heater circuit The problem of being damaged at IGBT module.

In a first aspect, the present invention provides a kind of electromagnetic heating circuit, comprising: microprocessing unit, level shifting circuit, waveform Translation circuit, push-pull circuit and insulated gate bipolar transistor IGBT module；

Wherein, the first output end of the microprocessing unit is connect with the input terminal of the level shifting circuit, described micro- The second output terminal of processing unit is connect with the input terminal of the waveform convertion circuit, the input terminal of the push-pull circuit respectively with The output end of the level shifting circuit is connected with the output end of the waveform convertion circuit, the output end of the push-pull circuit with The input terminal of the IGBT module connects；

The microprocessing unit, for detecting the actual power and target voltage of electromagnetic heating utensil；

The microprocessing unit is also used to control the waveform convertion circuit and is less than in the actual power of electromagnetic heating utensil The predetermined power and when target voltage is not preset threshold is in the conductive state, so that the push-pull circuit drives the IGBT Module is in amplification region；

The microprocessing unit is also used to control the waveform convertion circuit and is less than in the actual power of electromagnetic heating utensil Predetermined power and the target voltage are in an off state when being preset threshold, so that the push-pull circuit drives the IGBT mould Block is in saturation conduction area；

Wherein, the target voltage is the supply voltage of the electromagnetic heating circuit, and the preset threshold is the electricity The valley of the supply voltage of magnetic heater circuit, alternatively, the supply voltage that the target voltage is the electromagnetic heating circuit rectifies Voltage afterwards, and the preset threshold is the valley of the supply voltage rectified voltage of the electromagnetic heating circuit.

Optionally, the microprocessing unit, for determining the actual power less than predetermined power and determining the mesh Voltage is marked when not being preset threshold, Xiang Suoshu waveform convertion circuit sends Continuity signal, and Xiang Suoshu level shifting circuit sends the One pulse signal, the Continuity signal for being connected the waveform convertion circuit, and be connected to the waveform convertion circuit with it is described The connection of push-pull circuit, first pulse signal is used for so that the push-pull circuit sends the first driving letter to IGBT module Number, first driving signal is for driving IGBT module to be in amplification region.

Optionally, the microprocessing unit is also used to determining the actual power less than described in predetermined power and determination When target voltage is preset threshold, Xiang Suoshu waveform convertion circuit sends cut-off signals, and Xiang Suoshu level shifting circuit sends the Two pulse signals, the cut-off signals for closing the waveform convertion circuit, and disconnect the waveform convertion circuit with it is described The connection of push-pull circuit, second pulse signal is used for so that the push-pull circuit sends the second driving to the IGBT module Signal, second driving signal is for driving the IGBT module to be in saturation conduction area, and second driving signal Amplitude is greater than the amplitude of the first driving signal, and/or, the high-pulse widths of second driving signal are greater than the first driving signal High-pulse widths.

Optionally, the microprocessing unit is also used to when determining that the actual power is greater than or equal to predetermined power, to The waveform convertion circuit sends cut-off signals, and Xiang Suoshu level shifting circuit sends third pulse signal, the cut-off signals For closing the waveform convertion circuit, and disconnect the connection of the waveform convertion circuit and the push-pull circuit, the third Pulse signal is used for so that the push-pull circuit sends third driving signal to the IGBT module, and the third driving signal is used It is in saturation conduction area in the driving IGBT module, and the amplitude of the third driving signal is greater than the width of the first driving signal Value, and/or, the high-pulse widths of the third driving signal are greater than the high-pulse widths of the first driving signal.

Optionally,

The input terminal of the microprocessing unit is connect with the feeder ear of the electromagnetic heating circuit, for obtaining the target Voltage；Alternatively, the input terminal of the microprocessing unit is connect with the rectification output end of the supply voltage of the electromagnetic heating circuit, For obtaining the target voltage；

The microprocessing unit, is also used to obtain target current, and the target current is the reality of the electromagnetic heating utensil Border electric current；

The microprocessing unit is also used to determine the electromagnetic heating according to the target voltage and the target current The actual power of utensil.

Optionally, the microprocessing unit includes: micro-control unit MCU, voltage detecting circuit and current detection circuit；

Wherein, the input terminal of the voltage detecting circuit is the input terminal of the microprocessing unit, for obtaining the mesh Mark voltage；

The current detection circuit, for obtaining the target current；

The first input end of the MCU is connect with the output end of the voltage detecting circuit, the second input terminal of the MCU It is connect with the output end of the current detection circuit, the first output end of the MCU and the input terminal of the level shifting circuit Connection, the second output terminal of the MCU are connect with the input terminal of the waveform convertion circuit.

Optionally, the waveform convertion circuit includes: first switch module, diode and first capacitor；

Wherein, the first end of the first switch module is connect with the second output terminal of the microprocessing unit, and described The second end of one switch module is connect with the cathode of the first end of the first capacitor and the diode respectively, first electricity The second end of appearance is connect with the input terminal of the push-pull circuit, and the third end of the first switch module and the diode are just Pole ground connection；

The microprocessing unit is used to send the Continuity signal to the first switch module, so that the first switch Module closure；

The microprocessing unit is also used to send the cut-off signals to the first switch module, so that described first opens Module is closed to disconnect.

Optionally, the first switch module is triode and the 6th resistance, alternatively, electronic switch.

Optionally, the level shifting circuit includes: first resistor, second resistance and second switch module；

Wherein, the first end of the first resistor connects the first level, the second end of the first resistor and described second The first end of resistance connects, and the first end of the second switch module is connected between first resistor and second resistance, and described the The second end of two switch modules is connect with the input terminal of the push-pull circuit, the third end of the second switch module and described the The second end of two resistance is grounded.

Optionally, the push-pull circuit include: 3rd resistor, third switch module, the 4th switch module, the 4th resistance with And the 5th resistance；

Wherein, the 3rd resistor first end connect the first level, the second end of the 3rd resistor respectively with it is described The output end of level shifting circuit, the output end of the waveform convertion circuit, the first end of the third switch module and institute The first end connection of the 4th switch module is stated, the second end of the third switch module connects first level, the third The third end of switch module is connect with the first end of the 4th resistance, and the second end of the 4th resistance is respectively with the described 4th The second end of switch module is connected with the first end of the 5th resistance, the third end ground connection of the 4th switch module, described The second end of 5th resistance is connect with the input terminal of the IGBT module.

Optionally, the push-pull circuit further include: the second capacitor；

Wherein, the first end of second capacitor is connect with the second end of the 3rd resistor, and the of second capacitor Two ends ground connection.

Optionally, the electromagnetic heating circuit further include: rectification circuit, filter circuit and resonance circuit；

Wherein, the rectification circuit is for rectifying the supply voltage of the electromagnetic heating circuit, the rectified current The positive output end on road is connect with the first input end of the filter circuit, the first output end of the filter circuit with it is described humorous The input terminal connection of vibration circuit, the output end of the resonance circuit is connect with the first output end of the IGBT module, described whole The negative sense output end of current circuit is connect with the second input terminal of the filter circuit, the second output terminal of the filter circuit and institute The second output terminal for stating IGBT module is grounded.

Optionally, the first input end of the voltage detecting circuit is connect with the positive input of the rectification circuit, institute The second input terminal for stating voltage detecting circuit is connect with the negative input of the rectification circuit, for obtaining the target electricity Pressure；Alternatively,

The first input end of the voltage detecting circuit is connect with the positive input of the rectification circuit, the voltage inspection The connection of the first input end of the second input terminal and filter circuit of slowdown monitoring circuit, for obtaining the target voltage.

Optionally, the first input end of the current detection circuit is connect with the second output terminal of the filter circuit, institute The second input terminal for stating current detection circuit is connect with the second output terminal of the IGBT module, for obtaining the target electricity Stream.

Second aspect, the present invention provide a kind of electromagnetic heating utensil, comprising: electromagnetic heating electricity as described in relation to the first aspect Road.

The third aspect, the present invention provide a kind of current control process, comprising:

Obtain the actual power of electromagnetic heating utensil；

Being less than predetermined power in the actual power for determining the electromagnetic heating utensil and determine target voltage not is default threshold When value, the first pulse signal is inputted to level shifting circuit, and it is in the conductive state to control waveform convertion circuit, so as to recommend electricity The electric current of road driving IGBT module is in amplification region；

When the actual power for determining electromagnetic heating utensil is less than predetermined power and determines that target voltage is preset threshold, to Level shifting circuit inputs the second pulse signal, and it is in an off state to control waveform convertion circuit, so that push-pull circuit drives IGBT module is in saturation conduction area；

Wherein, the target voltage is the supply voltage of electromagnetic heating circuit, and the preset threshold is that the electromagnetism adds The valley of the supply voltage of heater circuit, alternatively, the target voltage is the voltage after the supply voltage rectification of electromagnetic heating circuit, And the preset threshold is the valley of the supply voltage rectified voltage of the electromagnetic heating circuit 0.

Optionally, described to be less than predetermined power in the actual power for determining the electromagnetic heating utensil and determine target voltage When not being preset threshold, the first pulse signal is inputted to level shifting circuit, and it is in the conductive state to control waveform convertion circuit, So that push-pull circuit driving IGBT module is in amplification region, comprising:

Continuity signal is sent to the waveform convertion circuit, the Continuity signal is used to that the waveform convertion circuit to be connected, And the connection of connection the waveform convertion circuit and the push-pull circuit；

The first pulse signal is sent to the level shifting circuit, first pulse signal is used for so that described recommend electricity Road direction IGBT module sends the first driving signal, and first driving signal is for driving IGBT module to be in amplification region.

Optionally, described to be less than predetermined power in the actual power for determining electromagnetic heating utensil and determine that target voltage is pre- If when threshold value, the second pulse signal is inputted to level shifting circuit, and it is in an off state to control waveform convertion circuit, so as to push away It draws circuit drives IGBT module and is in saturation conduction area, comprising:

Cut-off signals are sent to the waveform convertion circuit, the cut-off signals are used to close the waveform convertion circuit, And disconnect the connection of the waveform convertion circuit and the push-pull circuit；

The second pulse signal is sent to the level shifting circuit, second pulse signal is used for so that described recommend electricity IGBT module described in road direction sends the second driving signal, and second driving signal is for driving the IGBT module to be in saturation Area is connected, and the amplitude of second driving signal is greater than the amplitude of the first driving signal, and/or, second driving signal High-pulse widths be greater than the first driving signal high-pulse widths.

Optionally, when determining that the actual power is greater than or equal to predetermined power, the method also includes:

Third pulse signal is sent to the level shifting circuit, the third pulse signal is used for so that described recommend electricity IGBT module described in road direction sends third driving signal, and the third driving signal is for driving the IGBT module to be in saturation Area is connected, and the amplitude of the third driving signal is greater than the amplitude of the first driving signal, and/or, the third driving signal High-pulse widths be greater than the first driving signal high-pulse widths.

Optionally, the actual power for obtaining electromagnetic heating utensil, comprising:

The target voltage and target current are obtained, the target current is the actual current of the electromagnetic heating utensil；

According to the target voltage and target current, the actual power of the electromagnetic heating utensil is determined.

Electromagnetic heating circuit, electromagnetic heating utensil and current control process provided by the invention, can by microprocessing unit To obtain the actual power and target voltage of electromagnetic heating utensil in real time.It is less than in the actual power for determining electromagnetic heating utensil pre- If power and determining target voltage when not being preset threshold, microprocessing unit can control the conducting of waveform convertion circuit, and to electricity Flat conversion circuit sends the first pulse signal so that waveform convertion circuit participates in the work of push-pull circuit, in turn, push-pull circuit to The driving voltage that IGBT module is sent reduces, so that IGBT module is in amplification region, the electric current of the IGBT module in amplification region It is smaller, reduce the loss of IGBT module.Voltage as target voltage is constantly close to preset threshold, in IGBT module drain electrode Change until being minimum value, at this point, being less than predetermined power in the actual power for determining electromagnetic heating utensil and determining target voltage When for preset threshold, microprocessing unit can control the shutdown of waveform convertion circuit, and send the second pulse to level shifting circuit Signal, so that waveform convertion circuit is no longer participate in the work of push-pull circuit, in turn, what push-pull circuit can be sent to IGBT module Driving voltage does not change, so that IGBT module can realize electromagnetic heating utensil under small-power state with saturation conduction Normal work.The present invention solves existing electromagnetic heating circuit and is connected since electromagnetic heating utensil is under small-power state IGBT module transient current is excessive and the problem of causing IGBT module to damage, by being in small-power state in electromagnetic heating utensil The lower driving voltage for reducing IGBT module reduces the electric current of IGBT module so that IGBT module is in amplification region, to reduce The loss of IGBT module extends the service life of IGBT module, improves the reliability of IGBT module, so that electromagnetic heater Tool with normal heating, can save the component cost of electromagnetic heating utensil.

Detailed description of the invention

It, below will be to embodiment or existing in order to clearly demonstrate the embodiment of the present invention or technical solution in the prior art Attached drawing needed in technical description is briefly described, it should be apparent that, the accompanying drawings in the following description is the present invention Some embodiments of embodiment, for those of ordinary skill in the art, without any creative labor, also Other drawings may be obtained according to these drawings without any creative labor.

Fig. 1 is the structural schematic diagram of electromagnetic heating circuit provided by the invention；

Fig. 2 a is the envelope waveform schematic diagram of the voltage in electromagnetic heating circuit provided by the invention in IGBT module drain electrode；

Fig. 2 b is the first driving signal that push-pull circuit is sent to IGBT module in electromagnetic heating circuit provided by the invention With the waveform diagram of the second driving signal；

Fig. 3 is the structural schematic diagram of electromagnetic heating circuit provided by the invention；

Fig. 4 a is the circuit diagram of electromagnetic heating circuit provided by the invention；

Fig. 4 b is the circuit diagram of electromagnetic heating circuit provided by the invention；

Fig. 5 a is the structural schematic diagram of electromagnetic heating circuit provided by the invention；

Fig. 5 b is the circuit diagram of electromagnetic heating circuit provided by the invention；

Fig. 6 is the structural schematic diagram of electromagnetic heating utensil provided by the invention；

Fig. 7 is the flow diagram of current control process provided by the invention.

Appended drawing reference:

100-electromagnetic heating circuits；101-microprocessing units；

102-level shifting circuits；103-waveform convertion circuits；

104-push-pull circuits；105-IGBT modules；

106—MCU；107-voltage detecting circuits；

108-current detection circuits；109-rectification circuits；

110-filter circuits；111-resonance circuits；

10-electromagnetic heating utensils.

Specific embodiment

In order to make the object, technical scheme and advantages of the embodiment of the invention clearer, below in conjunction with the embodiment of the present invention In attached drawing, technical scheme in the embodiment of the invention is clearly and completely described, it is clear that described embodiment is A part of the embodiment of the embodiment of the present invention, instead of all the embodiments.Based on the embodiment in the embodiment of the present invention, this field Those of ordinary skill's every other embodiment obtained without making creative work, belongs to implementation of the present invention The range of example protection.

Currently, when electromagnetic heating utensil 10 is in low-power heating, in existing electromagnetic heating circuit, if in IGBT module In the case that 105 drain electrode still has certain voltage, IGBT module 105 is connected, and the transient current of conducting is larger, is easily caused The loss of IGBT module 105 improves the device cost of electromagnetic heating utensil 10.Wherein, the present embodiment is to small-power and high-power Specific corresponding performance number range is without limitation.Generally, low power performance number range is 0-1000 watts (W), powerful Performance number range is 1000W-2200W.

In view of the above-mentioned problems, the electromagnetic heating circuit 100 of the present embodiment can be in small-power in electromagnetic heating utensil 10 When heating, by reducing the driving voltage of IGBT module 105, to reduce the electric current of IGBT module 105, to reduce IGBT module 105 loss.

In the following, the specific structure of electromagnetic heating circuit 100 is described in detail by specific embodiment.Fig. 1 is this hair The structural schematic diagram of the electromagnetic heating circuit of bright offer, as shown in Figure 1, the electromagnetic heating circuit 100 of the present embodiment may include: Microprocessing unit 101, level shifting circuit 102, waveform convertion circuit 103, push-pull circuit 104 and insulated gate bipolar crystal Pipe IGBT module 105.

Wherein, the first output end of microprocessing unit 101 is connect with the input terminal of level shifting circuit 102, micro process list Member 101 second output terminal connect with the input terminal of waveform convertion circuit 103, the input terminal of push-pull circuit 104 respectively with level The output end of conversion circuit 102 is connected with the output end of waveform convertion circuit 103, the output end and IGBT mould of push-pull circuit 104 The input terminal of block 105 connects.

Microprocessing unit 101, for detecting the actual power and target voltage of electromagnetic heating utensil 10.

Microprocessing unit 101, the actual power for being also used to control waveform convertion circuit 103 in electromagnetic heating utensil 10 are less than Predetermined power and when target voltage is not preset threshold is in the conductive state, so that push-pull circuit 104 drives at IGBT module 105 In amplification region.

Microprocessing unit 101, the actual power for being also used to control waveform convertion circuit 103 in electromagnetic heating utensil 10 are less than Predetermined power and target voltage are in an off state when being preset threshold, so that push-pull circuit 104 drives IGBT module 105 to be in Saturation conduction area.

Wherein, target voltage is the supply voltage of electromagnetic heating circuit 100, and preset threshold is electromagnetic heating circuit 100 Supply voltage valley, alternatively, target voltage be electromagnetic heating circuit 100 supply voltage rectification after voltage, and it is default Threshold value is the valley of the supply voltage rectified voltage of electromagnetic heating circuit 100.

For the working condition of real-time monitoring electromagnetic heating utensil 10, in the present embodiment, microprocessing unit 101 can be to electricity The actual power of magnetic heating utensil 10 is detected.In turn, microprocessing unit 101 can compare actual power and predetermined power it Between size, determine the working condition that electromagnetic heating utensil 10 is presently in.

Wherein, predetermined power can be configured according to the actual conditions of electromagnetic heating utensil 10, can be to preset In microprocessing unit 101, it can also be set and be manually entered into microprocessing unit 101 according to being expected by user, this Embodiment does not limit this.

For ease of description, the present embodiment middle low power refers to that the actual power of electromagnetic heating utensil 10 is less than default function Situation corresponding to rate, the high-power actual power for referring to electromagnetic heating utensil 10 are greater than or equal to the corresponding feelings of predetermined power Condition.

It will be understood by those skilled in the art that when the actual power of electromagnetic heating utensil 10 is small-power, IGBT module In the case that 105 drain voltage is zero, conducting IGBT module 105 can just play the role of protect IGBT module 105, but In actual conditions, can still there be certain voltage in the drain electrode of IGBT module 105, and when having voltage in the drain electrode of IGBT module 105 When, the dash current that 105 saturation conduction of IGBT module generates is very big, easily leads to the electricity that IGBT module 105 instantaneously flows through hourglass source electrode It flows through greatly, even more than its range of safety operation, not only IGBT module 105 can generate noise, but also work long hours and be easy damage Bad component therefore, can be by reducing the electric current of IGBT module 105 at this time, so that electromagnetic heating utensil 10 in the present embodiment Small-power can be normally in.

Since the voltage in the drain electrode of IGBT module 105 is easy to be influenced by factors such as ambient enviroments, micro process list Member 101 does not detect the voltage in the drain electrode of IGBT module 105 directly.Again due to the valley of the supply voltage of electromagnetic heating circuit 100 Size be it is set, and valley voltage be easy obtain, therefore, microprocessing unit 101 can set target voltage as electromagnetism The supply voltage of heater circuit 100, at this point, preset threshold is the valley of the supply voltage of electromagnetic heating circuit 100.Micro process list Member 101 can also set target voltage as the voltage after the rectification of the supply voltage of electromagnetic heating circuit 100, at this point, preset threshold For the valley of the supply voltage rectified voltage of electromagnetic heating circuit 100.

Further, microprocessing unit 101 can know the actual power and target voltage of electromagnetic heating utensil 10 in real time, To which microprocessing unit 101 can be determined according to the size between the actual power and predetermined power of electromagnetic heating utensil 10 Whether electromagnetic heating utensil 10 is in small-power state, can also be determined according to the size between target voltage and preset threshold The upper voltage of the drain electrode of IGBT module 105 whether there is and determine the size of the voltage.

Specifically, the first output end of microprocessing unit 101, can by connecting with the input terminal of level shifting circuit 102 With to 102 transmission pulse signal of level shifting circuit, the second output terminal of microprocessing unit 101 by with waveform convertion circuit 103 input terminal connection can transmit signal to waveform convertion circuit 103.

Further, microprocessing unit 101 the actual power for determining electromagnetic heating utensil 10 be less than predetermined power and really When the voltage that sets the goal is not preset threshold, the first pulse signal is inputted to level shifting circuit 102, and control waveform convertion circuit 103 conductings, the waveform convertion circuit 103 after conducting participate in the work of push-pull circuit 104, can reduce level shifting circuit 102 It is input to the amplitude of the first pulse signal of push-pull circuit 104, so that push-pull circuit 104 is input to the driving of IGBT module 105 Voltage magnitude reduces, so that IGBT module 105 is in amplification region.

It will be understood by those skilled in the art that when IGBT module 105 is in amplification region, the conducting voltage of IGBT module 105 It is linear with the electric current of IGBT module 105, and the electric current of IGBT module 105 rises slowly, across after this area, IGBT module 105 are in saturation region, and the electric current rising of IGBT saturation conduction, IGBT module 105 is exceedingly fast, until maximum value.Therefore, IGBT module Via the electric current of source-drain electrode when can be less than 105 saturation conduction of IGBT module via the electric current of source-drain electrode when 105 amplification.

Further, for compared to the IGBT module 105 in existing electromagnetic heating circuit 100, by this present embodiment IGBT module 105 will not saturation conduction, but be in amplification region, therefore, the electric current of IGBT module 105 can be less than in the present embodiment Electric current when IGBT module 105 is connected in existing electromagnetic heating circuit 100 is saved to reduce the consumption of IGBT module 105 The component cost of electromagnetic heating utensil 10.

Further, after one section of preset duration (duration half period in the range of) usually in supply voltage, Target voltage can gradually become preset threshold, and microprocessing unit 101 can still determine 10 actual power of electromagnetic heating utensil at this time When still less than predetermined power, the second pulse signal is inputted to level shifting circuit 102, and controls the shutdown of waveform convertion circuit 103, Waveform convertion circuit 103 after shutdown cannot participate in the work of push-pull circuit 104, so that level shifting circuit 102 is input to and pushes away The amplitude for drawing the second pulse signal of circuit 104 does not change, so that push-pull circuit 104 is input to the drive of IGBT module 105 Dynamic voltage is constant, and IGBT module 105 may be at saturation conduction area at this time, to realize electromagnetic heating utensil 10 in small-power shape Heating process under state slows down the calorific value of IGBT module 105, reduces loss and the noise of IGBT module 105.

Wherein, the first pulse signal and the second pulse signal are different pulse signals, and the first driving signal and second drive Dynamic signal is different pulse signal.In general, low pulse width is less than low pulse in the second pulse signal in the first pulse signal Width, low pulse amplitude is less than low pulse amplitude in the second pulse signal in the first pulse signal, high arteries and veins in the first driving signal Width is rushed less than high-pulse widths in the second driving signal, high impulse amplitude is less than in the second driving signal in the first driving signal High impulse amplitude.And microprocessing unit 101 can be integrated chip, or the circuit that multiple components are built, this implementation Example does not limit this.

Further, in this embodiment whether electromagnetic heating circuit 100 can be in small function according to electromagnetic heating utensil 10 The working condition of rate, microprocessing unit 101 by control waveform convertion circuit 103 whether be connected to level shifting circuit 102 with Between push-pull circuit 104, thus it is possible to vary push-pull circuit 104 is sent to the driving voltage of IGBT module 105, so that IGBT module Working condition locating for 105 changes, so as to adjust via the electric current of 105 hourglass source electrode of IGBT module.

Determine electromagnetic heating utensil 10 be in actual power less than predetermined power small-power state and target voltage not When for preset threshold, under the control action of microprocessing unit 101, waveform convertion circuit 103 is connected, so that waveform convertion circuit 103 participate in the work of push-pull circuit 104, the driving voltage that push-pull circuit 104 is sent to IGBT module 105 are reduced, so that IGBT The driving voltage that module 105 receives is less than IGBT and is in voltage required when saturation conduction area such as, generally 13 volts of V, this When IGBT module 105 be in amplification region, the electric current of IGBT module 105 can be greatly lowered, so as to improve IGBT module 105 Working condition extends the service life of IGBT module 105.

In above process, target voltage can gradually become preset threshold, i.e. voltage in the drain electrode of IGBT module 105 can It gradually changes until becoming minimum value.Microprocessing unit 101 still determines that electromagnetic heating utensil 10 is small still in actual power at this time When the small-power state of predetermined power, under the control action of microprocessing unit 101, waveform convertion circuit 103 is turned off, so that Waveform convertion circuit 103 is no longer participate in the work of push-pull circuit 104, and push-pull circuit 104 is sent to IGBT module 105 The driving voltage of saturation conduction IGBT module 105, to realize the low-power heating process of electromagnetic heating utensil 10.

Electromagnetic heating circuit provided in this embodiment can obtain the reality of electromagnetic heating utensil by microprocessing unit in real time Border power and target voltage.It is less than predetermined power in the actual power for determining electromagnetic heating utensil and determines that target voltage is not pre- If when threshold value, microprocessing unit can control the conducting of waveform convertion circuit, and send the first pulse signal to level shifting circuit, So that waveform convertion circuit participates in the work of push-pull circuit, in turn, the driving voltage that push-pull circuit is sent to IGBT module is reduced, So that IGBT module is in amplification region, the electric current of the IGBT module in amplification region is smaller, reduces the loss of IGBT module.With Target voltage constantly close to preset threshold, the voltage in IGBT module drain electrode changes until being minimum value, at this point, in determination When the actual power of electromagnetic heating utensil is less than predetermined power and determines that target voltage is preset threshold, microprocessing unit can be controlled Waveform convertion circuit shutdown processed, and the second pulse signal is sent to level shifting circuit, so that waveform convertion circuit is no longer participate in The work of push-pull circuit, in turn, push-pull circuit can not change to the driving voltage that IGBT module is sent, so that IGBT mould Block can realize normal work of the electromagnetic heating utensil under small-power state with saturation conduction.The present embodiment solves existing That IGBT module transient current is connected is excessive and cause since electromagnetic heating utensil is under small-power state for electromagnetic heating circuit The problem of IGBT module is damaged, by reducing the driving voltage of IGBT module in the case where electromagnetic heating utensil is in small-power state, So that IGBT module is in amplification region, the electric current of IGBT module is reduced, to reduce the loss of IGBT module, extends IGBT The service life of module improves the reliability of IGBT module, so that electromagnetic heating utensil can save electromagnetism with normal heating Heat the component cost of utensil.

For ease of description, in the present embodiment, the first output end of microprocessing unit 101 can be the port PPG, micro process The second output terminal of unit 101 can be the port CON.

Optionally, microprocessing unit 101, for determining that actual power is less than predetermined power and determines that target voltage is not When preset threshold, Continuity signal is sent to waveform convertion circuit 103, the first pulse signal is sent to level shifting circuit 102, leads Messenger is connected to the connection of waveform convertion circuit 103 and push-pull circuit 104, the first arteries and veins for waveform convertion circuit 103 to be connected Signal is rushed for so that push-pull circuit 104 sends the first driving signal to IGBT module 105, the first driving signal to be for driving IGBT module 105 is in amplification region.

Specifically, microprocessing unit 101 is less than predetermined power and determination in the actual power for determining electromagnetic heating utensil 10 When target voltage is not preset threshold, Continuity signal can be sent to waveform convertion circuit 103 by the port CON, and pass through PPG Port sends the first pulse signal to level shifting circuit 102, leads at this point, Continuity signal can control waveform convertion circuit 103 It is logical so that waveform convertion circuit 103 is connected to push-pull circuit 104, the first pulse signal can allow push-pull circuit 104 to IGBT module 105 sends the first driving signal.

Further, when IGBT module 105 receives first driving signal, the driving that IGBT module 105 receives is electric Pressure is smaller, can make itself to be in amplification region, and the electric current of IGBT module 105 can be less than IGBT module 105 and lead in saturation at this time Electric current when logical.

Optionally, microprocessing unit 101 are also used to determining that actual power is less than predetermined power and determines that target voltage is When preset threshold, cut-off signals are sent to waveform convertion circuit 103, the second pulse signal is sent to level shifting circuit 102, closes Break signal disconnects the connection of waveform convertion circuit 103 and push-pull circuit 104, the second arteries and veins for closing waveform convertion circuit 103 Signal is rushed for so that push-pull circuit 104 sends the second driving signal to IGBT module 105, the second driving signal to be for driving IGBT module 105 is in saturation conduction area, and the amplitude of the second driving signal is greater than the amplitude of the first driving signal, and/or, the The high-pulse widths of two driving signal are greater than the high-pulse widths of the first driving signal.

Specifically, microprocessing unit 101 is less than predetermined power and target in the actual power for determining electromagnetic heating utensil 10 Voltage be preset threshold when, can by the port CON to waveform convertion circuit 103 send cut-off signals, and by the port PPG to Level shifting circuit 102 sends the second pulse signal, at this point, cut-off signals can control the shutdown of waveform convertion circuit 103, so that Waveform convertion circuit 103 is no longer connected to push-pull circuit 104, since the amplitude of the second pulse signal is greater than the first pulse signal Amplitude, and/or, the low pulse width of the second pulse signal is greater than the low pulse width of the first pulse signal, therefore, the second pulse Signal can make push-pull circuit 104 send the second driving signal to IGBT module 105, thus, the amplitude of the second driving signal Greater than the amplitude of the first driving signal, and/or, the high-pulse widths of the second driving signal are greater than the high impulse of the first driving signal Width.

Further, when IGBT module 105 receives second driving signal, which can drive IGBT 105 saturation conduction of module slows down IGBT module to realize heating process of the electromagnetic heating utensil 10 under small-power state 105 calorific value reduces loss and the noise of IGBT module 105.

Optionally, microprocessing unit 101 are also used to when determining that actual power is greater than or equal to predetermined power, to waveform Translation circuit 103 sends cut-off signals, sends third pulse signal to level shifting circuit 102, cut-off signals are for closing wave Fractal transform circuit 103, and the connection of waveform convertion circuit 103 and push-pull circuit 104 is disconnected, third pulse signal is used for so that pushing away It draws circuit 104 and sends third driving signal to IGBT module 105, third driving signal is for driving IGBT module 105 to be in full With conducting area, and the amplitude of third driving signal be greater than the first driving signal amplitude, and/or, the high arteries and veins of third driving signal Rush the high-pulse widths that width is greater than the first driving signal.

Specifically, microprocessing unit 101 can pass through the end CON when determining that actual power is greater than or equal to predetermined power Mouth sends cut-off signals to waveform convertion circuit 103, and sends third pulse letter to level shifting circuit 102 by the port PPG Number, at this point, cut-off signals ensure that waveform convertion circuit 103 turns off, so that waveform convertion circuit 103 and push-pull circuit 104 are no longer Connection, since the amplitude of third pulse signal is greater than the amplitude of the first pulse signal, and/or, the low pulse of third pulse signal Width be greater than the first pulse signal low pulse width, therefore, third pulse signal can allow push-pull circuit 104 to IGBT module 105 sends third driving signal, thus, the amplitude of third driving signal is greater than the amplitude of the first driving signal, and/ Or, the high-pulse widths of third driving signal are greater than the high-pulse widths of the first driving signal.

Wherein, the first pulse signal and third pulse signal are different pulse signals, and the first driving signal and third are driven Dynamic signal is different pulse signal.In general, low pulse width is less than low pulse in third pulse signal in the first pulse signal Width, low pulse amplitude is less than low pulse amplitude in third pulse signal, high arteries and veins in the first driving signal in the first pulse signal It rushes width and is less than high-pulse widths in third driving signal, high impulse amplitude is less than in third driving signal in the first driving signal High impulse amplitude.And second pulse signal and third pulse signal can be identical pulse signal, or different arteries and veins Signal is rushed, only need to guaranteeing the second pulse signal, low pulse amplitude is identical with third pulse signal.When the second pulse signal When from third pulse signal being different pulse signals, low pulse width is less than low in third pulse signal in the second pulse signal Pulse width, low pulse amplitude is equal to low pulse amplitude in third pulse signal in the second pulse signal, in the second driving signal High-pulse widths are less than high-pulse widths in third driving signal, and high impulse amplitude is equal to third driving letter in the second driving signal High impulse amplitude in number.

Further, when IGBT module 105 receives the third driving signal, which can drive IGBT 105 saturation conduction of module, to realize heating process of the electromagnetic heating utensil 10 under high power work state.

Wherein, the setting of the first driving signal, the second driving signal and third driving signal may include a variety of, this implementation Example does not limit this.Under normal circumstances, the first driving signal can be the driving pulse of high level narrower width, to guarantee Voltage in the drain electrode of IGBT module 105 finally minimizes under the electric current of lesser IGBT module 105.Second driving signal and Third driving signal all can be the driving pulse of high level, to guarantee that IGBT module 105 can be with saturation conduction.

Further, electromagnetic heating circuit 100 can be in small-power or powerful according to electromagnetic heating utensil 10 Working condition, microprocessing unit 101 is by controlling whether waveform convertion circuit 103 is connected to level shifting circuit 102 and recommends Between circuit 104, thus it is possible to vary push-pull circuit 104 is sent to the driving voltage of IGBT module 105, so that 105 institute of IGBT module Place's working condition changes, so as to adjust the electric current of IGBT module 105.

Determine electromagnetic heating utensil 10 be in actual power less than predetermined power small-power state and target voltage not When for preset threshold, under the control action of microprocessing unit 101, waveform convertion circuit 103 is connected, so that waveform convertion circuit 103 participate in the work of push-pull circuit 104, and push-pull circuit 104 can send the first driving signal to IGBT module 105, this first The driving voltage that driving signal receives IGBT module 105 is less than required voltage when IGBT saturation conduction, at this time IGBT mould Block 105 is in amplification region, and the electric current of IGBT module 105 can be greatly lowered, so as to improve the work shape of IGBT module 105 Condition extends the service life of IGBT module 105.In above process, target voltage can gradually become preset threshold, micro process list Member 101 at this time still determine electromagnetic heating utensil 10 be in actual power less than predetermined power small-power state when, in micro process Under the control action of unit 101, waveform convertion circuit 103 is turned off, so that waveform convertion circuit 103 is no longer participate in push-pull circuit 104 work, at this point, push-pull circuit 104 can send the second driving signal to IGBT module 105, which makes 105 saturation conduction of IGBT module is obtained, to realize the low-power heating process of electromagnetic heating utensil 10.

Determine electromagnetic heating utensil 10 be in actual power be greater than or equal to predetermined power high-power state when, micro- Under the control action of processing unit 101, waveform convertion circuit 103 is turned off, and microprocessing unit may be implemented in level shifting circuit 102 5V can be converted to 13V by the conversion process of voltage transmitted by 101 under normal circumstances, and in turn, push-pull circuit 104 can be to IGBT module 105 sends third driving signal, so that 105 saturation conduction of IGBT module, to realize electromagnetic heating utensil 10 High-power heating process.

Wherein, preset threshold is different, and the process that the voltage in the drain electrode of IGBT module 105 changes is different.In the following, in conjunction with Fig. 2 a Process is implemented to it with Fig. 2 b to be described in detail.

When microprocessing unit 101 determines that the actual power of electromagnetic heating utensil 10 is less than predetermined power and target voltage and is not When the valley of the supply voltage of electromagnetic heating circuit 100 or supply voltage rectified voltage, at this point, as shown in Figure 2 a, IGBT mould Voltage in the drain electrode of block 105 can be gradually decreased from certain value, until for the valley of drain voltage, generally zero, wherein IGBT mould The period that voltage in the drain electrode of block 105 is gradually reduced corresponds to t1-t2.Accordingly, as shown in Figure 2 b, first driving signal For amplitude Va less than the amplitude VCC of the second driving signal, the duty ratio of the first driving signal is higher than the duty ratio of the second driving signal.

Further, microprocessing unit 101 can control IGBT module 105 and receive the second driving signal, and make IGBT module 105 is in saturation conduction area, wherein in the envelope waveform such as Fig. 2 b of the drain voltage of IGBT module 105 when t2-t3 Between the corresponding waveform of section.

Electromagnetic heating circuit provided in this embodiment can obtain the reality of electromagnetic heating utensil by microprocessing unit in real time Border power and target voltage.It is less than predetermined power in the actual power for determining electromagnetic heating utensil and determines that target voltage is not pre- If when threshold value, microprocessing unit can send Continuity signal to waveform convertion circuit, and send the first arteries and veins to level shifting circuit Signal is rushed, so that waveform convertion circuit is connected, push-pull circuit can send the first driving signal to IGBT module, so that IGBT mould Block is in amplification region, to reduce the electric current of IGBT module, reduces the loss of IGBT module.As target voltage is continuous Close to preset threshold, the voltage in IGBT module drain electrode changes until being minimum value, at this point, in the reality for determining electromagnetic heating utensil When border power is less than predetermined power and determines that target voltage is preset threshold, microprocessing unit can be sent to waveform convertion circuit Cut-off signals, and the second pulse signal is sent to level shifting circuit, so that waveform convertion circuit turns off, push-pull circuit can be to IGBT module sends the second driving signal, so that IGBT module saturation conduction, so that electromagnetic heating utensil can be in small-power shape It is worked normally under state.When the actual power for determining electromagnetic heating utensil is greater than or equal to predetermined power, microprocessing unit can be with Cut-off signals are sent to waveform convertion circuit, and send third pulse signal to level shifting circuit, so that waveform convertion circuit Shutdown, push-pull circuit can send third driving signal to IGBT module, so that IGBT module saturation conduction, thus electromagnetic heating Utensil can work normally under high-power state.In the present embodiment, solves existing electromagnetic heating circuit due to electromagnetic heating Utensil be under small-power state be connected IGBT module transient current it is excessive and the problem of cause IGBT module to damage, by electricity Magnetic heating utensil is under small-power state the driving voltage for reducing IGBT module, so that IGBT module is in amplification region, reduces The electric current of IGBT module extends the service life of IGBT module to reduce the loss of IGBT module, improves IGBT mould The reliability of block so that electromagnetic heating utensil not only can under small-power state normal heating, can also be in high power work Normal heating under state has saved the component cost of electromagnetic heating utensil.

On the basis of above-mentioned Fig. 1 embodiment, since preset threshold may include a variety of ways of realization, micro process The mode that unit 101 obtains target voltage includes a variety of.In the following, to the available target voltage of microprocessing unit 101 and electromagnetism The detailed process for heating the actual current of utensil 10 is described in detail.

Optionally, the input terminal of microprocessing unit 101 is connect with the feeder ear of electromagnetic heating circuit 100, for obtaining mesh Mark voltage；Alternatively, the input terminal of microprocessing unit 101 is connect with the rectification output end of the supply voltage of electromagnetic heating circuit 100, For obtaining target voltage；

Microprocessing unit 101, is also used to obtain target current, and target current is the actual current of electromagnetic heating utensil 10；

Microprocessing unit 101 is also used to determine the practical function of electromagnetic heating utensil 10 according to target voltage and target current Rate.

Specifically, the input terminal of microprocessing unit 101 can by the connection of the feeder ear with electromagnetic heating circuit 100, Target voltage, the present embodiment can also be obtained by the connection of the rectification output end of the supply voltage with electromagnetic heating circuit 100 It does not limit this.

Further, microprocessing unit 101 passes through the actual current of the target voltage and electromagnetic heating utensil 10 that get, Determine the actual power of electromagnetic heating utensil 10.Wherein, the present embodiment obtains the specific reality of target current to microprocessing unit 101 Existing mode is without limitation.

Further, according to the function of microprocessing unit 101, microprocessing unit 101 can be divided into multiple composition portions Point.Below with reference to Fig. 3, the specific structure of microprocessing unit 101 is described in detail.Fig. 3 is that electromagnetism provided by the invention adds The structural schematic diagram of heater circuit, as shown in figure 3, on the basis of electromagnetic heating circuit 100 shown in Fig. 1, optionally, micro process Unit 101 may include: micro-control unit (Microcontroller Unit, MCU) 106, voltage detecting circuit 107 and electricity Current detection circuit 108.

Wherein, the input terminal of voltage detecting circuit 107 is the input terminal of microprocessing unit 101, for obtaining target voltage.

Current detection circuit 108, for obtaining target current.

The first input end of MCU106 is connect with the output end of voltage detecting circuit 107, the second input terminal of MCU106 with The output end of current detection circuit 108 connects, and the first output end of MCU106 is connect with the input terminal of level shifting circuit 102, The second output terminal of MCU106 is connect with the input terminal of waveform convertion circuit 103.

For the working condition of real-time monitoring electromagnetic heating utensil 10, in the present embodiment, voltage detecting circuit 107 can be right Target voltage is detected, and target voltage is sent to microprocessing unit 101, and microprocessing unit 101 is obtained in real time Get target voltage.Current detection circuit 108 can detect target current, and target current is sent to micro process list Member 101, allows microprocessing unit 101 to get target current in real time, so that microprocessing unit 101 can be according to target electricity Pressure and target current calculate the actual power of electromagnetic heating utensil 10.In turn, microprocessing unit 101 can compare electromagnetic heating Size between the actual power and predetermined power of utensil 10 determines the working condition that electromagnetism utensil is presently in.

Further, voltage detecting circuit 107 can be by the connection of the feeder ear with electromagnetic heating circuit 100, to obtain The supply voltage of electromagnetic heating circuit 100, i.e. target voltage are taken, the supply voltage with electromagnetic heating circuit 100 can also be passed through Rectification output end connection, the voltage after supply voltage rectification to obtain electromagnetic heating circuit 100, i.e. target voltage.Into And microprocessing unit 101 can compare the size between the target voltage and preset threshold, so that it is determined that IGBT module 105 is leaked Whether there is voltage on extremely and determines the size of the upper voltage of the drain electrode of IGBT module 105.

Wherein, voltage detecting circuit 107 and current detection circuit 108 can be integrated chip, or multiple member devices The circuit that part is built, the present embodiment do not limit this.

On the basis of above-mentioned Fig. 1 or Fig. 3 embodiment, in conjunction with Fig. 4 a and Fig. 4 b, to 100 medium wave deformation of electromagnetic heating circuit The specific structure for changing circuit 103 is described in detail.Fig. 4 a is the circuit diagram of electromagnetic heating circuit provided by the invention, figure 4b is the circuit diagram of electromagnetic heating circuit provided by the invention, as shown in figures 4 a and 4b, optionally, waveform convertion circuit 103 may include: first switch module, diode and first capacitor.

Wherein, the first end of first switch module is connect with the second output terminal of microprocessing unit 101, first switch module Second end connect respectively with the cathode of the first end of first capacitor and diode, the second end and push-pull circuit of first capacitor 104 input terminal connection, the third end of first switch module and the plus earth of diode.

Microprocessing unit 101 is used to send Continuity signal to first switch module, so that first switch module is closed.Micro- place Reason unit 101 is also used to send cut-off signals to first switch module, so that first switch module disconnects.

In the present embodiment, first switch module can play the role of switch, and the concrete form of first switch module can be with Including a variety of, as shown in fig. 4 a, first switch module can be triode Q1 and the 6th resistance R6, and as shown in Figure 4 b, first opens Closing module can be electronic switch K.For ease of description, in Fig. 4 a and Fig. 4 b, diode is labeled as D1, and first capacitor is labeled as C2, microprocessing unit 101 are illustrated respectively labeled as MCU106.

Specifically, since the actual power in electromagnetic heating utensil 10 is less than predetermined power and target voltage is not default threshold When value, waveform convertion circuit 103 is just connected, and participates in the work of push-pull circuit 104, and therefore, microprocessing unit 101 can pass through The port CON sends Continuity signal to first switch module, and first capacitor is connect with push-pull circuit 104, in turn, is being pushed away Under the driving effect for drawing circuit 104, when the driving voltage that IGBT module 105 receives is less than 105 saturation conduction of IGBT module Driving voltage reduces 105 transient current of IGBT module, plays the role of protecting IGBT module 105.

Further, since the actual power in electromagnetic heating utensil 10 is greater than or equal to predetermined power or target voltage When for preset threshold, waveform convertion circuit 103 is turned off, and is not involved in the work of push-pull circuit 104, therefore, microprocessing unit 101 Cut-off signals can be sent to first switch module by the port CON, first capacitor is disconnected with push-pull circuit 104 and is connected It connects.

Further, when first capacitor is connect with push-pull circuit 104, diode is reversed cut-off.First capacitor with When push-pull circuit 104 disconnects, one end of diode is grounded, and can provide circuit for the electric discharge of first capacitor, also prevent and First capacitor has the electric current on the component of connection reversely to flow in first switch module, plays the work of protection first switch module With.

Secondly, continuing with Fig. 4 a or Fig. 4 b, to the specific structure of level shifting circuit 102 in electromagnetic heating circuit 100 It is described in detail.As shown in Fig. 4 a or Fig. 4 b, optionally, level shifting circuit 102 may include: first resistor, the second electricity Resistance and second switch module.

Wherein, the first end of first resistor connects the first level, the second end of first resistor and the first end of second resistance Connection, the first end of second switch module is connected between first resistor and second resistance, the second end of second switch module with The input terminal of push-pull circuit 104 connects, and the third end of second switch module and the second end of second resistance are grounded.

For ease of description, in Fig. 4 a and Fig. 4 b, second switch module is illustrated with triode Q2, first resistor label For R1, second resistance is labeled as R2, is illustrated respectively.

Specifically, microprocessing unit 101 can be presently in working condition according to electromagnetic heating general ability, to level conversion electricity Road 102 sends different pulse signals.It is not when the actual power of electromagnetic heating utensil 10 is less than predetermined power and target voltage When preset threshold, microprocessing unit 101 can send the first pulse signal to level shifting circuit 102；When electromagnetic heating utensil For 10 actual power less than predetermined power and when target voltage is preset threshold, microprocessing unit 101 can be to level conversion electricity Road 102 sends the second pulse signal；When the actual power of electromagnetic heating utensil 10 is greater than or equal to predetermined power, micro process list Member 101 can send third pulse signal to level shifting circuit 102.

Further, the pulse signal received can be carried out level conversion by level shifting circuit 102, and is transferred to Push-pull circuit 104, so that the available driving voltage for meeting 105 current working status of IGBT module of push-pull circuit 104.

Then, continuing with Fig. 4 a or Fig. 4 b, the specific structure of push-pull circuit 104 in electromagnetic heating circuit 100 is carried out It is described in detail.As shown in Fig. 4 a or Fig. 4 b, optionally, push-pull circuit 104 may include: 3rd resistor, third switch module, Four switch modules, the 4th resistance and the 5th resistance.

Wherein, 3rd resistor first end connect the first level, the second end of 3rd resistor respectively with level shifting circuit 102 output end, the output end of waveform convertion circuit 103, the first end of third switch module and the 4th switch module One end connection, the second end of third switch module connect the first level, and the of the third end of third switch module and the 4th resistance One end connection, the second end of the 4th resistance are connect with the first end of the second end of the 4th switch module and the 5th resistance respectively, the The third end of four switch modules is grounded, and the second end of the 5th resistance is connect with the grid of IGBT module 105.

In the present embodiment, for ease of description, 3rd resistor is labeled as R3 in Fig. 4 a and Fig. 4 b, and third switch module is with three Pole pipe Q3 is illustrated respectively, and the 4th switch module is illustrated with triode Q4, and the 4th resistance mark is R4, the 5th resistance mark R5 is denoted as to be illustrated respectively.

Specifically, it is less than predetermined power in the actual power of electromagnetic heating utensil 10 and target voltage is not preset threshold When, microprocessing unit 101 can send the first pulse signal, and microprocessing unit to level shifting circuit 102 by the port PPG 101 can also be by the port CON to 103 pieces of transmission Continuity signals of waveform convertion circuit, so that in waveform convertion circuit 103 One capacitor can be connect with push-pull circuit 104, that is, under the effect of the first level, first capacitor can be in charged state, with the The voltage at one capacitor both ends is gradually increased, and third switch module can be connected.

Further, by be arranged first capacitor charge constant be greater than microprocessing unit 101 by the port PPG to The time width for the first pulse signal that level shifting circuit 102 is sent, to control the voltage at first capacitor both ends less than first Level, without being equal to first voltage, and the first level is equal with the amplitude of the second driving signal, therefore, push-pull circuit 104 to The driving voltage that IGBT module 105 exports is less than driving voltage when 105 saturation conduction of IGBT module, to reduce IGBT mould The transient current of block 105 plays the role of protecting IGBT module 105 and extends 105 service life of IGBT module.

Further, it is less than predetermined power in the actual power of electromagnetic heating utensil 10 and target voltage is preset threshold When, microprocessing unit 101 can send the second pulse letter to level shifting circuit 102 by the port PPG after one section of duration Number, and microprocessing unit 101 can also be by the port CON to 103 pieces of transmission cut-off signals of waveform convertion circuit, so that waveform becomes The first capacitor changed in circuit 103 is not connect with push-pull circuit 104, and second switch module turns off in level shifting circuit 102, electricity Second switch module works normally in flat conversion circuit 102, allows third switch module and the 4th normal work of switch module Make, and the amplitude of the second pulse signal is equal with the first level, therefore, the driving that push-pull circuit 104 is exported to IGBT module 105 Voltage can make 105 saturation conduction of IGBT module, allow electromagnetic heating utensil 10 normal under low-duty Heating.

Further, when the actual power of electromagnetic heating utensil 10 is greater than or equal to predetermined power, microprocessing unit 101 Third pulse signal can be sent to level shifting circuit 102 by the port PPG, and microprocessing unit 101 can also pass through CON Port to 103 pieces of transmission cut-off signals of waveform convertion circuit so that first capacitor in waveform convertion circuit 103 not with recommend electricity Road 104 connects, and second switch module works normally in level shifting circuit 102, so that third switch module and the 4th switching molding Block can work normally, and the amplitude of third pulse signal is equal with the first level, and therefore, push-pull circuit 104 is to IGBT module The driving voltage of 105 outputs can make 105 saturation conduction of IGBT module, allow electromagnetic heating utensil 10 in small-power work Make normal heating under state.

In addition, optionally, push-pull circuit 104 can also include: the second capacitor continuing with Fig. 4 a or Fig. 4 b.In order to just The second capacitor is labeled as C1 in explanation, Fig. 4 a and Fig. 4 b.

Wherein, the second end connection of the first end and 3rd resistor of the second capacitor, the second end ground connection of the second capacitor.

In the present embodiment, when waveform convertion circuit 103 is connect with push-pull circuit 104, first capacitor and the second capacitor are simultaneously Connection connection, the voltage for being transferred to third switch module and the 4th switch module is the voltage of first capacitor and the second capacitor both ends, The voltage needs to be less than the first level, therefore, can be greater than by the charge constant of setting first capacitor and the second capacitor The time width for the first pulse signal that microprocessing unit 101 is sent by the port PPG to level shifting circuit 102, to control The voltage at first capacitor and the second capacitor both ends is less than the first level, without being equal to first voltage, and the first level and second The amplitude of driving signal is equal, and therefore, the driving voltage that push-pull circuit 104 is exported to IGBT module 105 is less than IGBT module 105 Driving voltage when saturation conduction plays protection IGBT module to reduce the instantaneous drain-source electrode current of IGBT module 105 105 and extend 105 service life of IGBT module effect.

Then, in conjunction with Fig. 5 a and Fig. 5 b, the specific structure that the electromagnetic heating circuit 100 to the present embodiment includes carries out detailed Explanation.Fig. 5 a is the structural schematic diagram of electromagnetic heating circuit provided by the invention, and Fig. 5 b is electromagnetic heating electricity provided by the invention The circuit diagram on road.As shown in Figure 5 a, on the basis of Fig. 1 or Fig. 3, electromagnetism adds the electromagnetic heating circuit 100 of the present embodiment Heater circuit 100 can also include: rectification circuit 109, filter circuit 110 and resonance circuit 111.

Wherein, rectification circuit 109 is used to rectify the supply voltage of electromagnetic heating circuit 100, rectification circuit 109 Positive output end is connect with the first input end of filter circuit 110, the first output end and resonance circuit 111 of filter circuit 110 Input terminal connection, the output end of resonance circuit 111 connect with the drain electrode of IGBT module 105, and the negative sense of rectification circuit 109 exports End is connect with the second input terminal of filter circuit 110, and the second output terminal of filter circuit 110 and the source electrode of IGBT module 105 are equal Ground connection.

In the present embodiment, rectification circuit 109 can be by the supply voltage of input such as commercial power rectification at pulsating dc voltage, side Just 111 operating voltage of resonance circuit is supplied.Wherein, supply voltage can be the single-phase sinusoidal voltage of 220V, 50HZ, can also Think that the mains supply after transformation, the present embodiment do not limit this, only needs the type of supply voltage can satisfy various Work requirements.And rectification circuit 109 can be full-bridge rectifier, or half bridge rectifier, the present embodiment is to this Without limitation.

In the present embodiment, filter circuit 110 plays the role of filtering.Further optionally, voltage detecting circuit 107 with it is whole The positive input of current circuit 109 connects, and the second input terminal of voltage detecting circuit 107 and the negative sense of rectification circuit 109 input End connection, for obtaining target voltage；Alternatively,

The first input end of voltage detecting circuit 107 is connect with the positive input of rectification circuit 109, voltage detecting circuit The connection of 107 the second input terminal and the first input end of filter circuit 110, for obtaining target voltage.

In the present embodiment, due to electromagnetic heating utensil 10 supply voltage respectively with the drain voltage paddy of IGBT module 105 Value is not much different at the time of corresponding, and therefore, in the present embodiment, voltage detecting circuit 107 can be with the input of rectification circuit 109 End connection, in turn, voltage detecting circuit 107 can by detection target voltage whether be electromagnetic heating utensil 10 supply voltage Valley, come the presence or absence of drain voltage for determining IGBT module 105 and size.

Again due to electromagnetic heating utensil 10 supply voltage arrange after voltage respectively with the drain voltage of IGBT module 105 It is not much different at the time of corresponding to valley, therefore, in the present embodiment, voltage detecting circuit 107 can also be connected to rectification circuit Between 109 and filter circuit 110, in turn, whether voltage detecting circuit 107 can be electromagnetic heater by detection target voltage The valley of voltage after the supply voltage of tool 10 arranges, come the presence or absence of drain voltage for determining IGBT module 105 and size.

Wherein, the present embodiment to the specific implementation of voltage detecting circuit 107 without limitation, only need microprocessing unit 101 can quickly determine IGBT by being compared to the target voltage received from voltage detecting circuit 107 with preset threshold The drain electrode of module 105 whether there is voltage, facilitate subsequent corresponding operating.

For example, when voltage detecting circuit 107 and supply voltage are directly connected to, since supply voltage is alternating current, Two backward diodeds being connected in parallel can be set in voltage detecting circuit 107, using components such as voltage sensors, to mesh Mark voltage is detected.It, can be direct when voltage detecting circuit 107 is connected between rectification circuit 109 and filter circuit 110 Using components such as voltage sensors, target voltage is detected.

Optionally, the first input end of current detection circuit 108 is connect with the second output terminal of filter circuit 110, electric current Second input terminal of detection circuit 108 is connect with the second output terminal of IGBT module 105, for obtaining target current.

Specifically, current detection circuit 108 is available by being connected between resonance circuit 111 and IGBT module 105 To target current.Due to electric current and bad acquisition, current detection circuit 108, which can pass through, obtains small ohmically voltage Target current is obtained, due to small ohmically voltage and little, current detection circuit 108 can arrive the voltage input In amplifier in MCU106, to obtain accurate target current.

In a specific embodiment, as shown in Figure 5 b, voltage detecting circuit 107 may include two diode D1 and D2, two resistance R7 and R8 and capacitor C5, wherein the anode of D1 is connect with the positive input of rectification circuit 109, and D2 is just Pole is connect with the negative input of rectification circuit 109, and the cathode of D1 and the cathode of D2 are all connected with one end of R7, the other end point of R7 It is not connect with one end of the first input end of MCU106, one end of R8 and C5, the other end of R8 and the other end of C5 are grounded. Current detection circuit 108 may include resistance RZ1, resistance R9, resistance R10 and capacitor C6, wherein one end of RZ1 respectively with The negative sense output end of rectification circuit 109 is connected with one end of R9, and the other end of RZ1 and the source electrode of IGBT module 105, R9's is another End is connect with the input terminal of amplifier in MCU106, the supply voltage of one end connection MCU106 of R10, the other end difference of R10 Connect one end of C6 and the other end of R9, the other end ground connection of C6.

In the present embodiment, push-pull circuit 104 can by the driving voltage of output, come drive the conducting of IGBT module 105 and Shutdown allows resonance circuit 111 to emit electromagnetic energy according to the switch state of IGBT module 105 and treats heating equipment progress It heats, and can control the power rating of electromagnetic heating circuit 100 by the switch state of IGBT module 105.

Optionally, resonance circuit 111 may include: heating coil and resonant capacitance.Wherein, the first of filter circuit 110 Heating coil is connected in series between output end and the drain electrode of IGBT module 105, resonant capacitance is connected in parallel on the both ends of heating coil. Optionally, the magnetic material of heating coil is ferrite, iron silicon or iron sial.

Further, in this embodiment filter circuit 110 includes a variety of ways of realization, it need to only meet the tool of filter circuit 110 There is energy storage effect.In a kind of specific implementation form of filter circuit 110, optionally, filter circuit 110 may include: filter Wave inductance and filter capacitor；

Wherein, the input terminal of the positive output end of rectification circuit 109 and filter inductance connect, the first end of filter capacitor and Second end is connected in parallel between the output end of filter inductance and the negative sense output end of rectification circuit 109, and the first end of filter capacitor is also It is connect with the input terminal of resonance circuit 111.

In the present embodiment, filter inductance and filter capacitor play the role of filtering, when IGBT module 105 does not turn on, by It is connected in parallel in filter capacitor and finishing circuit, therefore, filter capacitor voltage can synchronize variation with the variation of alternating voltage. Wherein, the number and numerical value of filter inductance and filter capacitor can be selected according to the actual situation.

It should be understood that filter circuit 110, in addition to above-mentioned form, filter circuit 110 can also only include filter capacitor.

Fig. 6 is the structural schematic diagram of electromagnetic heating utensil provided by the invention, as shown in fig. 6, the electromagnetism of the present embodiment adds Hot utensil 10 includes: such as above-mentioned electromagnetic heating circuit 100.

Electromagnetic heating utensil 10 provided in this embodiment includes that above-mentioned reality can be performed such as above-mentioned electromagnetic heating circuit 100 Example is applied, implements principle and technical effect, reference can be made to the technical solution of above-mentioned Fig. 1-Fig. 5 b embodiment, the present embodiment is herein It repeats no more.

Fig. 7 is the flow diagram of current control process provided by the invention, as shown in fig. 7, the electric current tune of the present embodiment Section method may include:

S101, the actual power for obtaining electromagnetic heating utensil 10.

S102, it is less than predetermined power in the actual power for determining electromagnetic heating utensil 10 and determines that target voltage is not default When threshold value, the first pulse signal is inputted to level shifting circuit 102, and it is in the conductive state to control waveform convertion circuit 103, with The electric current for making push-pull circuit 104 drive IGBT module 105 is in amplification region.

S103, it is less than predetermined power in the actual power for determining electromagnetic heating utensil 10 and determines that target voltage is default threshold When value, the second pulse signal is inputted to level shifting circuit 102, and it is in an off state to control waveform convertion circuit 103, so that Push-pull circuit 104 drives IGBT module 105 to be in saturation conduction area.

In conjunction with Fig. 1-Fig. 5 b, the current control process of the present embodiment can be with the micro process list in electromagnetic heating circuit 100 Member 101 is executing subject, and above-described embodiment can be performed in detailed process, principle and technical effect is implemented, reference can be made to above-mentioned The technical solution of Fig. 1-Fig. 5 b illustrated embodiment, details are not described herein again.

On the basis of Fig. 7 embodiment, a kind of specific implementation of S102 can be with are as follows: optionally, to waveform convertion electricity Road 103 sends Continuity signal, and Continuity signal is connected to waveform convertion circuit 103 and recommends for waveform convertion circuit 103 to be connected The connection of circuit 104；

To level shifting circuit 102 send the first pulse signal, the first pulse signal be used for so that push-pull circuit 104 to IGBT module 105 sends the first driving signal, and the first driving signal is for driving IGBT module 105 to be in amplification region.

On the basis of Fig. 7 embodiment, a kind of specific implementation of S103 are as follows: optionally, to waveform convertion circuit 103 Cut-off signals are sent, cut-off signals disconnect waveform convertion circuit 103 and push-pull circuit for closing waveform convertion circuit 103 104 connection；

To level shifting circuit 102 send the second pulse signal, the second pulse signal be used for so that push-pull circuit 104 to IGBT module 105 sends the second driving signal, and the second driving signal is used to that IGBT module 105 to be driven to be in saturation conduction area, and The amplitude of second driving signal is greater than the amplitude of the first driving signal, and/or, the high-pulse widths of the second driving signal are greater than the The high-pulse widths of one driving signal.

On the basis of Fig. 7 embodiment, optionally, when determining that actual power is greater than or equal to predetermined power, this implementation Example current control process can also include:

Cut-off signals are sent to waveform convertion circuit 103, cut-off signals are disconnected for closing waveform convertion circuit 103 The connection of waveform convertion circuit 103 and push-pull circuit 104；

To level shifting circuit 102 send third pulse signal, third pulse signal be used for so that push-pull circuit 104 to IGBT module 105 sends third driving signal, and third driving signal is used to that IGBT module 105 to be driven to be in saturation conduction area, and The amplitude of third driving signal is greater than the amplitude of the first driving signal, and/or, the high-pulse widths of third driving signal are greater than the The high-pulse widths of one driving signal.

On the basis of Fig. 7 embodiment, a kind of specific implementation of S101 are as follows: optionally, obtain target voltage and mesh Electric current is marked, target current is the actual current of electromagnetic heating utensil 10；

According to target voltage and target current, the actual power of electromagnetic heating utensil 10 is determined.

The current control process of the present embodiment, can be performed the embodiment of above-mentioned electromagnetic heating circuit 100, and specific implementation is former Reason and technical effect, reference can be made to the technical solution of above-mentioned Fig. 1-Fig. 5 b illustrated embodiment, details are not described herein again.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention., rather than its limitations；To the greatest extent Pipe present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that: its according to So be possible to modify the technical solutions described in the foregoing embodiments, or to some or all of the technical features into Row equivalent replacement；And these are modified or replaceed, various embodiments of the present invention technology that it does not separate the essence of the corresponding technical solution The range of scheme.

Claims

1. a kind of electromagnetic heating circuit (100) characterized by comprising microprocessing unit (101), level shifting circuit (102), waveform convertion circuit (103), push-pull circuit (104) and insulated gate bipolar transistor IGBT module (105)；

Wherein, the first output end of the microprocessing unit (101) is connect with the input terminal of the level shifting circuit (102), The second output terminal of the microprocessing unit (101) is connect with the input terminal of the waveform convertion circuit (103), described to recommend electricity The input terminal on road (104) is defeated with the output end of the level shifting circuit (102) and the waveform convertion circuit (103) respectively Outlet connection, the output end of the push-pull circuit (104) are connect with the input terminal of the IGBT module (105)；

The microprocessing unit (101), for detecting the actual power and target voltage of electromagnetic heating utensil (10)；

The microprocessing unit (101) is also used to control the waveform convertion circuit (103) in the reality of electromagnetic heating utensil (10) Border power is less than predetermined power and in the conductive state when the target voltage is not preset threshold, so that the push-pull circuit (104) IGBT module (105) is driven to be in amplification region；

The microprocessing unit (101) is also used to control the waveform convertion circuit (103) in the reality of electromagnetic heating utensil (10) Border power is less than predetermined power and in an off state when the target voltage is preset threshold, so that the push-pull circuit (104) IGBT module (105) is driven to be in saturation conduction area；

Wherein, the target voltage is the supply voltage of the electromagnetic heating circuit (100), and the preset threshold is the electricity The valley of the supply voltage of magnetic heater circuit (100), alternatively, the target voltage is the confession of the electromagnetic heating circuit (100) Voltage after piezoelectric voltage rectification, and the preset threshold is the supply voltage rectified voltage of the electromagnetic heating circuit (100) Valley.

2. electromagnetic heating circuit (100) according to claim 1, which is characterized in that the microprocessing unit (101) is used In when determining that the actual power is less than predetermined power and determines that the target voltage is not preset threshold, Xiang Suoshu waveform becomes It changes circuit (103) and sends Continuity signal, Xiang Suoshu level shifting circuit (102) sends the first pulse signal, the Continuity signal For the waveform convertion circuit (103) to be connected, and it is connected to the waveform convertion circuit (103) and the push-pull circuit (104) Connection, first pulse signal be used for so that the push-pull circuit (104) to IGBT module (105) send first driving letter Number, first driving signal is for driving IGBT module (105) to be in amplification region.

3. electromagnetic heating circuit (100) according to claim 1, which is characterized in that the microprocessing unit (101), also For when determining that the actual power is less than predetermined power and determines that the target voltage is preset threshold, Xiang Suoshu waveform to become It changes circuit (103) and sends cut-off signals, Xiang Suoshu level shifting circuit (102) sends the second pulse signal, the cut-off signals For closing the waveform convertion circuit (103), and disconnect the waveform convertion circuit (103) and the push-pull circuit (104) Connection, second pulse signal be used for so that the push-pull circuit (104) Xiang Suoshu IGBT module (105) send second drive Dynamic signal, second driving signal is for driving the IGBT module (105) to be in saturation conduction area, and second driving The amplitude of signal is greater than the amplitude of the first driving signal, and/or, the high-pulse widths of second driving signal are greater than first and drive The high-pulse widths of dynamic signal.

4. electromagnetic heating circuit (100) according to claim 1, which is characterized in that the microprocessing unit (101), also For when determining that the actual power is greater than or equal to predetermined power, Xiang Suoshu waveform convertion circuit (103) to send shutdown letter Number, Xiang Suoshu level shifting circuit (102) sends third pulse signal, and the cut-off signals are for closing the waveform convertion electricity Road (103), and disconnect the connection of the waveform convertion circuit (103) and the push-pull circuit (104), the third pulse signal For making the push-pull circuit (104) Xiang Suoshu IGBT module (105) send third driving signal, the third driving signal For driving the IGBT module (105) to be in saturation conduction area, and the amplitude of the third driving signal is greater than the first driving The amplitude of signal, and/or, the high-pulse widths of the third driving signal are greater than the high-pulse widths of the first driving signal.

5. electromagnetic heating circuit (100) according to claim 1-4, which is characterized in that

The input terminal of the microprocessing unit (101) is connect with the feeder ear of the electromagnetic heating circuit (100), for obtaining State target voltage；Alternatively, the supply voltage of the input terminal of the microprocessing unit (101) and the electromagnetic heating circuit (100) Rectification output end connection, for obtaining the target voltage；

The microprocessing unit (101), is also used to obtain target current, and the target current is the electromagnetic heating utensil (10) Actual current；

The microprocessing unit (101) is also used to determine the electromagnetic heating according to the target voltage and the target current The actual power of utensil (10).

6. electromagnetic heating circuit (100) according to claim 5, which is characterized in that microprocessing unit (101) packet It includes: micro-control unit MCU (106), voltage detecting circuit (107) and current detection circuit (108)；

Wherein, the input terminal of the voltage detecting circuit (107) is the input terminal of the microprocessing unit (101), for obtaining The target voltage；

The current detection circuit (108), for obtaining the target current；

The first input end of the MCU (106) is connect with the output end of the voltage detecting circuit (107), the MCU (106) The second input terminal connect with the output end of the current detection circuit (108), the first output end of the MCU (106) and institute State the input terminal connection of level shifting circuit (102), the second output terminal of the MCU (106) and the waveform convertion circuit (103) input terminal connection.

7. electromagnetic heating circuit (100) according to claim 1-4, which is characterized in that the waveform convertion electricity Road (103) includes: first switch module, diode and first capacitor；

Wherein, the first end of the first switch module is connect with the second output terminal of the microprocessing unit (101), and described The second end of one switch module is connect with the cathode of the first end of the first capacitor and the diode respectively, first electricity The second end of appearance is connect with the input terminal of the push-pull circuit (104), the third end of the first switch module and two pole The plus earth of pipe；

The microprocessing unit (101) is used to send the Continuity signal to the first switch module, so that described first opens Close module closure；

The microprocessing unit (101) is also used to send the cut-off signals to the first switch module, so that described first Switch module disconnects.

8. electromagnetic heating circuit (100) according to claim 7, which is characterized in that the first switch module is three poles Pipe and the 6th resistance, alternatively, electronic switch.

9. electromagnetic heating circuit (100) according to claim 1-4, which is characterized in that the level conversion electricity Road (102) includes: first resistor, second resistance and second switch module；

Wherein, the first end of the first resistor connects the first level, the second end of the first resistor and the second resistance First end connection, the first end of the second switch module is connected between first resistor and second resistance, and described second opens Close module second end connect with the input terminal of the push-pull circuit (104), the third end of the second switch module with it is described The second end of second resistance is grounded.

10. electromagnetic heating circuit (100) according to claim 1-4, which is characterized in that the push-pull circuit It (104) include: 3rd resistor, third switch module, the 4th switch module, the 4th resistance and the 5th resistance；

Wherein, the 3rd resistor first end connect the first level, the second end of the 3rd resistor respectively with the level The first end of the output end of conversion circuit (102), the output end of the waveform convertion circuit (103), the third switch module And the first end connection of the 4th switch module, the second end of the third switch module connect first level, institute The third end for stating third switch module is connect with the first end of the 4th resistance, the second end of the 4th resistance respectively with institute The second end for stating the 4th switch module is connected with the first end of the 5th resistance, the third termination of the 4th switch module The second end on ground, the 5th resistance is connect with the input terminal of the IGBT module (105).

11. electromagnetic heating circuit (100) according to claim 10, which is characterized in that the push-pull circuit (104) is also wrapped It includes: the second capacitor；

Wherein, the first end of second capacitor is connect with the second end of the 3rd resistor, the second end of second capacitor Ground connection.

12. electromagnetic heating circuit (100) according to claim 6, which is characterized in that the electromagnetic heating circuit (100) Further include: rectification circuit (109), filter circuit (110) and resonance circuit (111)；

Wherein, the rectification circuit (109) is described for rectifying to the supply voltage of the electromagnetic heating circuit (100) The positive output end of rectification circuit (109) is connect with the first input end of the filter circuit (110), the filter circuit (110) the first output end is connect with the input terminal of the resonance circuit (111), the output end of the resonance circuit (111) with First output end of the IGBT module (105) connects, the negative sense output end and the filter circuit of the rectification circuit (109) (110) the second input terminal connection, the second of the second output terminal of the filter circuit (110) and the IGBT module (105) Output end is grounded.

13. electromagnetic heating circuit (100) according to claim 12, which is characterized in that the voltage detecting circuit (107) First input end connect with the positive input of the rectification circuit (109), the second of the voltage detecting circuit (107) is defeated Enter end to connect with the negative input of the rectification circuit (109), for obtaining the target voltage；Alternatively,

The first input end of the voltage detecting circuit (107) is connect with the positive input of the rectification circuit (109), described The connection of the first input end of the second input terminal and filter circuit (110) of voltage detecting circuit (107), for obtaining State target voltage.

14. electromagnetic heating circuit (100) according to claim 12, which is characterized in that the current detection circuit (108) First input end connect with the second output terminal of the filter circuit (110), the second of the current detection circuit (108) is defeated Enter end to connect with the second output terminal of the IGBT module (105), for obtaining the target current.

15. a kind of electromagnetic heating utensil (10) characterized by comprising as the described in any item electromagnetism of claim 1-14 add Heater circuit (100).

16. a kind of current control process characterized by comprising

Obtain the actual power of electromagnetic heating utensil (10)；

Being less than predetermined power in the actual power for determining the electromagnetic heating utensil (10) and determine target voltage not is default threshold When value, the first pulse signal is inputted to level shifting circuit (102), and it is in the conductive state to control waveform convertion circuit (103), So that the electric current of push-pull circuit (104) driving IGBT module (105) is in amplification region；

When the actual power for determining electromagnetic heating utensil (10) is less than predetermined power and determines that target voltage is preset threshold, to Level shifting circuit (102) inputs the second pulse signal, and it is in an off state to control waveform convertion circuit (103), so as to push away It draws circuit (104) driving IGBT module (105) and is in saturation conduction area；

Wherein, the target voltage is the supply voltage of electromagnetic heating circuit (100), and the preset threshold is that the electromagnetism adds The valley of the supply voltage of heater circuit (100), alternatively, the target voltage is whole for the supply voltage of electromagnetic heating circuit (100) Voltage after stream, and the preset threshold is the valley of the supply voltage rectified voltage of the electromagnetic heating circuit (100).

17. according to the method for claim 16, which is characterized in that described in the reality for determining the electromagnetic heating utensil (10) When border power is less than predetermined power and determines that target voltage is not preset threshold, the first arteries and veins is inputted to level shifting circuit (102) Signal is rushed, and it is in the conductive state to control waveform convertion circuit (103), so that push-pull circuit (104) drives IGBT module (105) In amplification region, comprising:

Continuity signal is sent to the waveform convertion circuit (103), the Continuity signal is for being connected the waveform convertion circuit And the connection of connection the waveform convertion circuit (103) and the push-pull circuit (104) (103),；

The first pulse signal is sent to the level shifting circuit (102), first pulse signal is used for so that described recommend Circuit (104) sends the first driving signal to IGBT module (105), and first driving signal is for driving IGBT module (105) it is in amplification region.

18. according to the method for claim 16, which is characterized in that described in the practical function for determining electromagnetic heating utensil (10) When rate is less than predetermined power and determines that target voltage is preset threshold, the second pulse signal is inputted to level shifting circuit (102), And it is in an off state to control waveform convertion circuit (103), so that push-pull circuit (104) driving IGBT module (105) is in full With conducting area, comprising:

Cut-off signals are sent to the waveform convertion circuit (103), the cut-off signals are for closing the waveform convertion circuit (103), and the connection of the waveform convertion circuit (103) and the push-pull circuit (104) is disconnected；

The second pulse signal is sent to the level shifting circuit (102), second pulse signal is used for so that described recommend Circuit (104) Xiang Suoshu IGBT module (105) sends the second driving signal, and second driving signal is for driving the IGBT Module (105) is in saturation conduction area, and the amplitude of second driving signal is greater than the amplitude of the first driving signal, and/or, The high-pulse widths of second driving signal are greater than the high-pulse widths of the first driving signal.

19. according to the method for claim 16, which is characterized in that preset function determining that the actual power is greater than or equal to When rate, the method also includes:

Third pulse signal is sent to the level shifting circuit (102), the third pulse signal is used for so that described recommend Circuit (104) Xiang Suoshu IGBT module (105) sends third driving signal, and the third driving signal is for driving the IGBT Module (105) is in saturation conduction area, and the amplitude of the third driving signal is greater than the amplitude of the first driving signal, and/or, The high-pulse widths of the third driving signal are greater than the high-pulse widths of the first driving signal.

20. the described in any item methods of 6-19 according to claim 1, which is characterized in that the acquisition electromagnetic heating utensil (10) Actual power, comprising:

The target voltage and target current are obtained, the target current is the actual current of the electromagnetic heating utensil (10)；

According to the target voltage and target current, the actual power of the electromagnetic heating utensil (10) is determined.