CN102905411B - Control circuit for cookware material judgment and method thereof - Google Patents

Control circuit for cookware material judgment and method thereof Download PDF

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Publication number
CN102905411B
CN102905411B CN201210394618.1A CN201210394618A CN102905411B CN 102905411 B CN102905411 B CN 102905411B CN 201210394618 A CN201210394618 A CN 201210394618A CN 102905411 B CN102905411 B CN 102905411B
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China
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described
igbt
mcu
pan
frequency
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CN201210394618.1A
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Chinese (zh)
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CN102905411A (en
Inventor
汪钊
李新峰
孙赫男
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美的集团股份有限公司
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Publication of CN102905411A publication Critical patent/CN102905411A/en
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Abstract

The invention discloses a control circuit for cookware material judgment and a method thereof. The method comprises the following steps: when an electromagnetic heating device works, a control unit controls an IGBT (Insulated Gate Bipolar Transistor) so as to enable a heating unit to heat; a signal generating unit outputs pulse signals to an MCU (Micro Controller Unit) of the control unit correspondingly according to the on/off state of the IGBT; the MCU records the input pulse signals and converts the pulse signals into frequency M; the frequency M is compared with preset frequency threshold N, and the type of cookware is determined to be A when the frequency M is higher than the preset frequency threshold N; the type of the cookware is determined to be B when the frequency M is less than or equal to the preset frequency threshold N; and the MCU adjusts related heating parameters according to the determined type of the cookware, so as to enable the electromagnetic heating device to adjust a heating state. The control circuit and the method have the advantages that an electromagnetic oven can be adjusted into a working state corresponding to the material of the cookware, the material of the cookware is judged in good time so as to carry out error check, and the like; and the material of the cookware is accurately updated so as to adjust the heating state and increase the heating efficiency.

Description

A kind of control circuit and method thereof judging pan material

Technical field

The present invention relates to a kind of control circuit and the method thereof that judge pan material.

Background technology

The material being applied to the pan of electromagnetic heater is numerous, and different from those when unlike material pan works on electromagnetic heater is very large, in order to allow electromagnetic heater be operated in optimum state, judges that the material of pan used is necessary.Method many employings electric current determination methods of current judgement pan type, namely when just starting to heat to the service time that IGBT mono-is fixing, detect IGBT and open the size of after-current, thus judge the material of pan.The shortcoming that the method exists just just judges pan material when just starting to heat, or just judge pan material when detecting and reheating without pot, once misjudgment, it is right so pan cannot to be sentenced again when follow-up laser heating, and different pan current difference influence by voltage under identical PPG is very large, easily causes erroneous judgement under different voltage.

Summary of the invention

For the shortcoming of prior art, the object of this invention is to provide a kind of control circuit and the method thereof that judge pan material.The present invention is used for judging to be placed on the material of the pan that electromagnetic heater heats, and according to the material adjustment heated condition of pan, electromagnetic heater is made to be adjusted to the operating state of corresponding pan material, there is low cost, reliably, judge with advantages such as error correction to pan material in good time, guarantee can accurately more pan material adjustment heated condition, submit to the efficiency of heating surface.

For achieving the above object, technical scheme of the present invention is: a kind of control method judging pan material, and it comprises the following steps:

(1), during electromagnetic heater work, control unit control IGBT makes heating unit heat;

(2) output pulse signal that described in signal generation unit, the on off state of IGBT is corresponding gives the MCU of described control unit;

(3) pulse signal of MCU record input, and convert described pulse signal to frequency M;

(4) frequency M and predeterminated frequency threshold value N is compared, when frequency M is greater than predeterminated frequency threshold value N, judge that pan type is A; If when frequency M is less than or equal to predeterminated frequency threshold value N, judge that pan type is B;

(5) according to the pan type judged, MCU adjusts associated heat parameter, makes electromagnetic heater adjust heated condition.

Also comprise step (a) before step (1), described step (a) detects on described electromagnetic heater whether be placed with pan, and after pan having been detected, described electromagnetic heater is started working.

In step (3), described MCU records high level, the low level pulse number that in certain hour, described IGBT on off state is corresponding, and becomes frequency M according to the time with the Automated generalization of pulse number and be stored in described MCU.

Described MCU records high level, the mode of low level pulse number is: the mode calculating or calculate by the number of low level appearance or be designated as with continuous print high level and low level one by the number of high level appearance calculates.

In described step (4), described MCU records its current PPG/PWM, and with described PPG/PWM for variable, calculates described predeterminated frequency threshold values N.

In step (2), when described IGBT opens, described signal generation unit exports high level, when described IGBT turns off, and described signal generation unit output low level; Or when described IGBT opens, described signal generation unit output low level, when described IGBT turns off, described signal generation unit exports high level.

Simultaneously, the present invention also provides a kind of control circuit judging pan material, it comprises the inversion unit be made up of IGBT and heating unit, signal generation unit and comprise the control unit of MCU, described signal generation unit is connected between described control unit input and described inversion unit, described control unit controls described heating unit by described IGBT and heats, the output pulse signal that described in described signal generation unit, the on off state of IGBT is corresponding gives the MCU of described control unit, described MCU is used for converting described pulse signal to frequency M, and described frequency M and predeterminated frequency threshold value N is compared, described MCU is also for judging pan type according to comparative result, and according to described pan type adjustment associated heat parameter.

Described MCU also for recording its current PPG/PWM, and with described PPG/PWM for variable, calculates described predeterminated frequency threshold values N.Described MCU comprises the pulse signal for recording described IGBT, and converts thereof into the frequency processing module of frequency M.Described MCU comprises for being compared by frequency M and predeterminated frequency threshold value N, and judges the pan type judging module of pan type according to comparative result.

Described signal generation unit is formed primarily of comparator U1, the change voltage that the on off state that comparator U1 receives described IGBT produces, and exports high level/low level accordingly according to described change voltage.

Described signal generation unit also comprises resistance R1, resistance R2, resistance R3 and resistance R4, and resistance R1 one end is connected to heating unit, and the other end is connected with one end of resistance R2, the negative input of comparator U1 respectively, resistance R2 other end ground connection; One end of resistance R3 is connected to the C pole of IGBT, the positive input of other end difference contact resistance R4 one end, comparator U1; Resistance R4 other end ground connection; The output of comparator U1 is connected with control unit.

Compared with prior art, beneficial effect of the present invention is:

(1) the present invention is by signalization generation unit between heating unit and control unit, signal generation unit can according to output pulse signal corresponding to the on off state of IGBT to control unit, control unit produces frequency M, frequency M and predeterminated frequency threshold value N is compared, and judges pan type according to comparative result.Therefore in heating process, the Push And Release continued by IGBT is to realize judging pan material repeatedly, even if occur erroneous judgement also can upper once judge time corrected, and pan material can be judged when pan switches fast, make electromagnetic heater accurately according to pan material adjustment heated condition, the efficiency of heating surface can be improved.

(2) present invention utilizes comparator as signal generation unit, not only structure is simple, and has the feature of low cost, dependable performance.

(3) the present invention can not influence by voltage when electromagnetic heater works, and anti-electromagnetic interference capability is strong.

Accompanying drawing explanation

Fig. 1 is pan determination methods flow chart of the present invention;

Fig. 2 is the schematic diagram of the control circuit of judgement pan material of the present invention.

Embodiment

Below in conjunction with embodiment and accompanying drawing, the present invention is described in detail.

The present embodiment is for electromagnetic oven, and as shown in Figure 1, the control method of the judgement pan material of electromagnetic oven of the present invention, comprises the steps:

(1), during electromagnetic oven work, control unit control IGBT makes heating unit heat;

(2) output pulse signal that described in signal generation unit, the on off state of IGBT is corresponding gives the MCU of described control unit;

(3) pulse signal of MCU record input, and convert described pulse signal to frequency M;

(4) frequency M and predeterminated frequency threshold value N is compared, when frequency M is greater than predeterminated frequency threshold value N, judge that pan type is A; If when frequency M is less than or equal to predeterminated frequency threshold value N, judge that pan type is B;

(5) according to the pan type judged, MCU adjusts associated heat parameter, makes electromagnetic oven adjust heated condition.

Further, also comprise step (a) before step (1), described step (a) detects on electromagnetic oven whether be placed with pan, and after pan having been detected, electromagnetic oven is started working.

Further, in step (3), described MCU records high level, the low level pulse number that in certain hour, IGBT on off state is corresponding, and becomes frequency M according to the time with the Automated generalization of pulse number and be stored in MCU.

Described MCU records high level, the mode of low level pulse number is: the mode calculating or calculate by the number of low level appearance or be designated as with continuous print high level and low level one by the number of high level appearance calculates.

Further, in step (4), described MCU records current PPG/PWM, and with current PPG for variable, calculates described predeterminated frequency threshold values N.

Further, in step (2), when described IGBT opens, described signal generation unit exports high level, when described IGBT turns off, and described signal generation unit output low level.In addition, also can be that, when described IGBT opens, described signal generation unit output low level, when described IGBT turns off, described signal generation unit exports high level.

The present invention also provides a kind of control circuit judging pan material simultaneously, it comprises the inversion unit be made up of IGBT and heating unit, signal generation unit and comprise the control unit of MCU, described signal generation unit is connected between described control unit input and described inversion unit, described control unit controls described heating unit by described IGBT and heats, the output pulse signal that described in described signal generation unit, the on off state of IGBT is corresponding gives the MCU of described control unit, described MCU is used for converting described pulse signal to frequency M, and described frequency M and predeterminated frequency threshold value N is compared, described MCU is also for judging pan type according to comparative result, and according to described pan type adjustment associated heat parameter.

Described MCU also for recording its current PPG/PWM, and with described PPG/PWM for variable, calculates described predeterminated frequency threshold values N.

Described MCU comprises the pulse signal for recording IGBT, and is changed into the frequency processing module of frequency M.Described MCU comprises for being compared by frequency M and predeterminated frequency threshold value N, and judges the pan type judging module of pan type according to comparative result.

Described signal generation unit is formed primarily of comparator U1, the change voltage that the on off state that comparator U1 receives described IGBT produces, and exports high level/low level accordingly according to described change voltage.

Described rectifying and wave-filtering unit is made up of rectifier bridge and the filter inductance L1 be connected with rectifier bridge, filter capacitor C1.Heating unit is made up of the resonant capacitance C2 be connected, coil panel L2.

Concrete, for realizing producing low and high level signal, if Fig. 2 is that frequency of the present invention judges the control circuit that pan material is detailed:

As shown in Figure 2, control circuit specifically comprises rectifier bridge, filter inductance L1, filter capacitor C1, resonant capacitance C2, coil panel L2, IGBT, IGBT drive circuit, resistance R1, resistance R2, comparator U1, resistance R3, resistance R4 and MCU;

Rectifier bridge forward output connects filter inductance L1, rectifier bridge negative sense output head grounding, the filter inductance L1 other end and filter capacitor C1 are connected to A point, and resonant capacitance C2 and coil panel L2 is connected in parallel, one end is connected to A point, and the other end is connected to B point and is extremely connected with the C of IGBT; The E pole ground connection of IGBT, G pole is connected with IGBT drive circuit; Resistance R1 is connected to A point, and the other end is connected with the negative input of resistance R2, comparator U1 respectively, resistance R2 other end ground connection; Resistance R3 is connected to B point, the positive input of other end difference contact resistance R4, comparator U1; Resistance R4 other end ground connection; The output of comparator U1 is connected with MCU; The PPG output port of MCU is connected with IGBT drive circuit.

For understanding the present invention further, operation principle of the present invention is described below:

After electromagnetic oven puts pan, coil panel L2 and pan form an equivalent inductance L by mutual inductance, and the equivalent inductance L produced after being coupled from different pans when coil panel L2 fixes is different.For stainless steel pan and stainless iron material pan, the equivalent inductance after stainless steel pan is coupled with coil panel L2 be less than stainless iron material be coupled with coil panel L2 after equivalent inductance, the course of work of electromagnetic oven and equivalent inductance have following relation:

During electromagnetic oven work, MCU controls IGBT drive circuit by the size of control PPG, IGBT drive circuit is for the switch of control IGBT, when IGBT opens, the C pole tension of IGBT is the low-voltage close to 0V, after IGBT opens a period of time, MCU control IGBT turns off, control circuit freedom of entry resonance condition, close at IGBT inductance L of having no progeny to charge to electric capacity C2, D point voltage rises, when energy in inductance is all transformed into after in electric capacity C2, C2 starts electric discharge, energy has C2 to shift to inductance L, when MCU detects that D point voltage is again open-minded by changing to lower than IGBT during C point voltage higher than C point voltage.Close at IGBT L and the C2 that has no progeny and be in resonance condition, the turn-off time depends on the size of L and C2.

When MCU controls IGBT drive circuit output high level by control PPG, control IGBT is open-minded, B point voltage is 0, A point voltage is voltage after rectifying and wave-filtering, now UC>UD, comparator output low level, start to rise when MCU closes by PPG control driver module control IGBT B point voltage of having no progeny, when rising to UC<UD, comparator exports high level, now MCU is open-minded by controlling driver module control IGBT, comparator exports high level, circulation like this, namely when in each switch periods, IGBT opens, comparator exports a high level, IGBT exports a low level when turning off, the IGBT turn-off time is relevant to equivalent inductance L, the L larger IGBT turn-off time is longer, when PPG determines, high level number and the low level number of comparator output in the unit interval are fewer, comparator output signal frequency is lower.

Described control unit also comprises the inspection pot module detecting and whether electromagnetic oven is placed with pan, heating unit is after confirmation is placed with pan, MCU is heated by PPG control IGBT, the number of high level in the frequency processing module record set time, according to the relation of time and number, pulse number being processed into frequency is stored in control unit, the present embodiment is the time in units of 500MS, the frequency M calculated in MCU reading frequency processing module, MCU calculates frequency threshold N according to PPG, with M-N, judge whether M-N is greater than 0, if fruit M-N is greater than 0, then be judged to pan type A by pan type judging module, if be less than 0, then be judged to pan type B, after judging pan type, MCU adjusts relevant parameter, electromagnetic oven is made to be operated in optimum Working.

The present invention is also applicable to electromagnetism rice cooker, prevention electromagnetic pressure cooker etc. and adopts electromagnetic principle to carry out in the electromagnetic heater heated.

Claims (10)

1. judge a control method for pan material, it is characterized in that, comprise the following steps:
(1), during electromagnetic heater work, control unit control IGBT makes heating unit heat;
(2) output pulse signal that described in signal generation unit, the on off state of IGBT is corresponding gives the MCU of described control unit;
(3) pulse signal of MCU record input, and convert described pulse signal to frequency M;
(4) frequency M and predeterminated frequency threshold value N is compared, when frequency M is greater than predeterminated frequency threshold value N, judge that pan type is A; If when frequency M is less than or equal to predeterminated frequency threshold value N, judge that pan type is B;
(5) according to the pan type judged, MCU adjusts associated heat parameter, makes electromagnetic heater adjust heated condition; Wherein, in described step (4), described MCU records its current PPG/PWM, and with described PPG/PWM for variable, calculates described predeterminated frequency threshold values N.
2. the control method of judgement pan material according to claim 1, it is characterized in that, also comprise step (a) before step (1), described step (a) detects on described electromagnetic heater whether be placed with pan, after pan having been detected, described electromagnetic heater is started working.
3. the control method of judgement pan material according to claim 2, it is characterized in that, in step (3), described MCU records high level, the low level pulse number that in certain hour, described IGBT on off state is corresponding, and becomes frequency M according to the time with the Automated generalization of pulse number and be stored in described MCU.
4. the control method of judgement pan material according to claim 3, it is characterized in that, the mode of described MCU record high level, low level pulse number is: the mode calculating or calculate by the number of low level appearance or be designated as with continuous print high level and low level one by the number of high level appearance calculates.
5. the control method of judgement pan material according to claim 3, is characterized in that, in step (2), when described IGBT opens, described signal generation unit exports high level, when described IGBT turns off, and described signal generation unit output low level; Or when described IGBT opens, described signal generation unit output low level, when described IGBT turns off, described signal generation unit exports high level.
6. one kind judges the control circuit of pan material, it is characterized in that, comprise the inversion unit be made up of IGBT and heating unit, signal generation unit and comprise the control unit of MCU, described signal generation unit is connected between described control unit input and described inversion unit, described control unit controls described heating unit by described IGBT and heats, the output pulse signal that described in described signal generation unit, the on off state of IGBT is corresponding gives the MCU of described control unit, described MCU is used for converting described pulse signal to frequency M, and described frequency M and predeterminated frequency threshold value N is compared, described MCU is also for judging pan type according to comparative result, and according to described pan type adjustment associated heat parameter, described MCU also for recording its current PPG/PWM, and with described PPG/PWM for variable, calculates described predeterminated frequency threshold values N.
7. the control circuit of judgement pan material according to claim 6, is characterized in that, described MCU comprises the pulse signal for recording described IGBT, and converts thereof into the frequency processing module of frequency M.
8. the control circuit of judgement pan material according to claim 6, is characterized in that, described MCU comprises for being compared by frequency M and predeterminated frequency threshold value N, and judges the pan type judging module of pan type according to comparative result.
9. the control circuit of the judgement pan material according to any one of claim 7 ~ 8, it is characterized in that, described signal generation unit is formed primarily of comparator U1, the change voltage that the on off state that comparator U1 receives described IGBT produces, and export high level/low level accordingly according to described change voltage.
10. the control circuit of judgement pan material according to claim 9, it is characterized in that, described signal generation unit also comprises resistance R1, resistance R2, resistance R3 and resistance R4, resistance R1 one end is connected to heating unit, the other end is connected with one end of resistance R2, the negative input of comparator U1 respectively, resistance R2 other end ground connection; One end of resistance R3 is connected to the C pole of IGBT, the positive input of other end difference contact resistance R4 one end, comparator U1; Resistance R4 other end ground connection; The output of comparator U1 is connected with control unit.
CN201210394618.1A 2012-10-17 2012-10-17 Control circuit for cookware material judgment and method thereof CN102905411B (en)

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Families Citing this family (10)

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Publication number Priority date Publication date Assignee Title
CN103607798B (en) * 2013-11-15 2015-09-02 美的集团股份有限公司 The detection method of pan type and electromagnetic heater
CN104214804B (en) * 2014-09-15 2017-01-25 佛山市顺德区美的电热电器制造有限公司 Electromagnetic heating device and cookware detecting method thereof
CN106153683A (en) * 2015-04-10 2016-11-23 佛山市顺德区美的电热电器制造有限公司 Detection device, method and cooking apparatus for the pan material of cooking apparatus
CN105125052B (en) * 2015-07-28 2017-06-16 小米科技有限责任公司 Power regulating method and device
CN105054805A (en) * 2015-08-18 2015-11-18 李智勇 Innovative automatic cooking IH heating device capable of controlling pots, water volumes and temperatures
CN105485734B (en) * 2015-12-24 2018-02-09 宁波德高软件技术有限公司 Pot system is examined in electromagnetic oven total digitalization pulse
CN107816935B (en) * 2016-09-14 2019-12-27 佛山市顺德区美的电热电器制造有限公司 Method and device for detecting deformation of cookware
CN106705146A (en) * 2017-01-16 2017-05-24 胡小庆 Electric heating furnace capable of intelligently switching heating modes
CN109931631A (en) * 2017-12-15 2019-06-25 佛山市顺德区美的电热电器制造有限公司 Heating device, cooking apparatus and method for heating and controlling
CN109959032A (en) * 2017-12-22 2019-07-02 佛山市顺德区美的电热电器制造有限公司 Electromagnetic oven, cookware kind identification method, device and readable storage medium storing program for executing

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE602007007434D1 (en) * 2006-02-02 2010-08-12 Panasonic Corp Induction heating device
CN201204713Y (en) * 2008-05-16 2009-03-04 美的集团有限公司 Protection circuit for electromagnetic heater control device
JP2011249187A (en) * 2010-05-28 2011-12-08 Sanyo Electric Co Ltd Electromagnetic cooker
CN102156415B (en) * 2011-01-24 2012-11-07 浙江爱仕达生活电器有限公司 Pan judgment circuit and judgment method thereof

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