CN106358328A - Soft switch detection and temperature control method of induction cooker - Google Patents

Soft switch detection and temperature control method of induction cooker Download PDF

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Publication number
CN106358328A
CN106358328A CN201610909036.0A CN201610909036A CN106358328A CN 106358328 A CN106358328 A CN 106358328A CN 201610909036 A CN201610909036 A CN 201610909036A CN 106358328 A CN106358328 A CN 106358328A
Authority
CN
China
Prior art keywords
circuit
detection
minimum duty
mcu controller
electromagnetic oven
Prior art date
Application number
CN201610909036.0A
Other languages
Chinese (zh)
Inventor
王孝洪
潘志锋
高军
Original Assignee
华南理工大学
广州韵脉质量技术服务有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
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Application filed by 华南理工大学, 广州韵脉质量技术服务有限公司 filed Critical 华南理工大学
Priority to CN201610909036.0A priority Critical patent/CN106358328A/en
Publication of CN106358328A publication Critical patent/CN106358328A/en

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Classifications

    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05BELECTRIC HEATING; ELECTRIC LIGHTING NOT OTHERWISE PROVIDED FOR
    • H05B6/00Heating by electric, magnetic, or electromagnetic fields
    • H05B6/02Induction heating
    • H05B6/06Control, e.g. of temperature, of power
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05BELECTRIC HEATING; ELECTRIC LIGHTING NOT OTHERWISE PROVIDED FOR
    • H05B6/00Heating by electric, magnetic, or electromagnetic fields
    • H05B6/02Induction heating
    • H05B6/10Induction heating apparatus, other than furnaces, for specific applications
    • H05B6/12Cooking devices
    • H05B6/1209Cooking devices induction cooking plates or the like and devices to be used in combination with them
    • H05B6/1227Cooking devices induction cooking plates or the like and devices to be used in combination with them for wok pans and wok pans supports for induction cooking plates

Abstract

The invention discloses a soft switch detection and temperature control method of an induction cooker. The soft switch detection and temperature control method of the induction cooker comprises a rectifying circuit, a resonance circuit, an IGBT circuit, an MCU controller, a drive circuit and a detection circuit, wherein the detection circuit comprises a zero-passing detection circuit and a Vce level detection circuit. The method comprises the following steps: firstly powering on, detecting the induction cooker, determining a minimum duty ratio by virtue of the zero-passing detection circuit and the Vce level detection circuit, determining whether a given power is greater than the minimum duty ratio or not, setting the duty ratio according to the given power if the given power is greater than the minimum duty ratio, and using a whole-period pulse time ratio control method if the given power is less than the minimum duty ratio. By adopting the soft switch detection and temperature control method, the switch loss is greatly reduced, a calorific value is reduced, the service life of the induction cooker is effectively prolonged, the safety and the stability of the induction cooker are improved, and the user requirement can be met.

Description

A kind of electromagnetic oven Sofe Switch detection and temperature-controlled process

Technical field

The present invention relates to electronic technology field is and in particular to a kind of electromagnetic oven Sofe Switch detects and temperature-controlled process.

Background technology

The most of electromagnetic ovens sold on current market, are all by rectification circuit is simply connected and shape with resonance circuit The topology becoming.Really utilize alternating current to produce the changing alternating magnetic field in direction by coil, be in alternating magnetic field The inside of conductor vortex current will occur, this is caused by eddy electric field promotes carrier moving in conductor;Vortex current Joule heating effect makes conductor heat up, thus realizing heating.This structure, when lower powered, because freewheel current is not enough, is led Cause igbt not enable soft open-minded, lead to heating serious, have impact on the life-span of electromagnetic oven.

Content of the invention

In order to overcome shortcoming and the deficiency of prior art presence, the present invention provides a kind of electromagnetic oven Sofe Switch detection and temperature Control method.

The present invention adopts the following technical scheme that

A kind of electromagnetic oven Sofe Switch detection and temperature-controlled process, including rectification circuit, resonance circuit, igbt circuit, mcu Controller, drive circuit and testing circuit, described testing circuit includes zero cross detection circuit and vce level sensitive circuit;

After described energising, three-phase electricity obtains unidirectional current by rectifier circuit rectifies, then supplies resonance circuit, is sent out by mcu Go out drive signal to drive circuit thus controlling the break-make of igbt circuit, described resonance circuit is connected with igbt circuit, described mistake The concrete connection of zero testing circuit, its outfan is connected with mcu controller;

Described vce level sensitive circuit is connected with the two ends of igbt circuit, and its outfan is connected with mcu controller;

Its method specifically comprises the following steps that

Step one electromagnetic oven is energized, and starts working;

Whether step 2 detection electromagnetic oven has pan, if it has, mcu then the concrete material according to pan and size are searched for Little dutycycle;

Particularly as follows: mcu controller provides a preliminary dutyfactor value, drive igbt circuit;

After zero cross detection circuit detects drum zero passage, start vce level sensitive circuit detection igbt both end voltage, work as inspection When the vce surveying is not less than setting value, then the dutycycle that mcu controller is given is unqualified, then changes preliminary dutyfactor value, under continuation Once search for;

If detection vce is less than setting value, preliminary dutyfactor value is qualified, and this value is set to the minimum under current working Dutycycle;

Step 3 when user selects electromagnetic oven low power run, tie according to minimum duty cycle value obtained above by electromagnetic oven Share the actual given operating power in family and adopt burst length complete cycle ratio control mode.

Change preliminary dutyfactor value and be specially linear change, including linearly increasing or linear minimizing.

Described burst length complete cycle ratio control mode particularly as follows:

Because dutycycle is proportional with the power of electromagnetic oven, then minimum duty cycle corresponds to operating power p1;

When the power p2 that user selects is less than power p1, then the output duty cycle of mcu is minimum duty cycle value, now will Operating frequency p1 divides according to equal proportion, and mcu sets the continuous control that power frequency period realizes power p 2.

It is impossible to be less than minimum duty cycle during electromagnetic oven normal work.

Beneficial effects of the present invention:

The present invention guarantees the reliable on off of igbt using soft switch technique detection technique, and effectively reduces switching loss, During low power run, burst length complete cycle ratio controls, and meets user's request, is effectively improved electromagnetic oven service life, improves it Safety and stability.

Brief description

Fig. 1 is the structural representation of hardware unit of the present invention;

Fig. 2 is the vce level sensitive circuit schematic diagram of the present invention;

Fig. 3 is testing circuit operation principle schematic diagram in the present invention;

Fig. 4 (a) is present invention ensure that working in the schematic diagram of the power grade of Sofe Switch;

Fig. 4 (b) is present invention ensure that working in each power grade adjusting power schematic diagram of 50% power grade of Sofe Switch;

Fig. 4 (c) is present invention ensure that working in each power grade adjusting power schematic diagram of 20% power grade of Sofe Switch.

Specific embodiment

With reference to embodiment and accompanying drawing, the present invention is described in further detail, but embodiments of the present invention are not It is limited to this.

Embodiment

A kind of detection of electromagnetic oven Sofe Switch and temperature-controlled process, as shown in figure 1, its hardware unit include rectification circuit, Resonance circuit, igbt circuit, mcu controller, drive circuit and testing circuit, described testing circuit include zero cross detection circuit and Vce level sensitive circuit;

After described energising, civil power 220v/ac obtains unidirectional current by rectifier circuit rectifies, then supplies resonance circuit, passes through Mcu sends drive signal to drive circuit thus controlling the break-make of igbt circuit, unidirectional current within the time of igbt circuit turn-on The induction charging of pressure resonance circuit, thus producing vortex current, final heat production, meet demand.

Described resonance circuit is connected with igbt, the concrete connection of described zero cross detection circuit,

Its outfan is connected with mcu;

As shown in Fig. 2 described vce level sensitive circuit is connected with the two ends of igbt circuit, its outfan is connected with mcu, Va and vb represents resonance potential.

Its method specifically comprises the following steps that

Step one electromagnetic oven is energized, and starts working;

Whether step 2 detection electromagnetic oven has pan, if it has, the mcu controller then concrete material according to pan and size Search minimum duty cycle;Described dutycycle is related to the material of pan and size, because different materials heating is different.

Particularly as follows: mcu provides a preliminary dutyfactor value, drive igbt circuit;

After zero cross detection circuit detects drum zero passage, start vce level sensitive circuit detection igbt circuit both end voltage, When the vce of detection is not less than setting value, then the dutycycle that mcu is given is unqualified, then changes preliminary dutyfactor value, continues next Secondary search;

If detection vce is less than setting value, described setting value is tried one's best and is selected the relatively low magnitude of voltage of ratio, then preliminary dutyfactor value Qualified, this value is set to the minimum duty cycle under current working;

Step 3 when user selects electromagnetic oven low power run, tie according to minimum duty cycle value obtained above by electromagnetic oven Share the actual given operating power in family and adopt burst length complete cycle ratio control mode.

As shown in figure 3, because the discharge time of vce is relevant with pan and line voltage, so start in electromagnetic oven When first carry out examine pot.In conjunction with figure three, mcu controller first provides the dutycycle of certain value, and in ta-tb section, this dutycycle is permissible Vce is detected and be less than certain setting value it can be determined that this dutycycle is qualified after drum zero passage.In tc-td section, mcu is given Dutycycle, between drum inverts twice, can't detect vce and is less than setting value, therefore judge that this dutycycle is unqualified.Thus search Rope goes out minimum duty cycle (power grade), in normal work it is ensured that being not less than this dutycycle, in order to avoid igbt circuit burns out, damages Bad electromagnetic oven.In the case that given dutycycle is less than minimum duty cycle, resonance current can not be reduced to zero it is impossible to realize soft opening Close, thus establishing minimum duty cycle.

The present invention, for low power run situation, obtains minimum duty cycle after judging by Sofe Switch detection, then with certain Dutyfactor value (more than minima) is as trigger.Then according to actual given power, using burst length complete cycle ratio Example control mode.It is assumed that it is 400w that user gives setting power as shown in Fig. 4 (a)-Fig. 4 (c), because being less than minimum duty cycle, According to setting dutyfactor value (being set to the corresponding dutycycle of 2000w) herein, can continuous 1 power frequency period accounting for according to 2000w The setting of empty ratio, then continuous 4 power frequency periods setting trigger is low, you can realize the low-power continuous control of 400w.

Above-described embodiment is the present invention preferably embodiment, but embodiments of the present invention are not subject to described embodiment Limit, other any spirit without departing from the present invention and the change made under principle, modification, replacement, combine, simplify, All should be equivalent substitute mode, be included within protection scope of the present invention.

Claims (4)

1. a kind of detection of electromagnetic oven Sofe Switch with temperature-controlled process it is characterised in that include rectification circuit, resonance circuit, Igbt circuit, mcu controller, drive circuit and testing circuit, described testing circuit includes zero cross detection circuit and the inspection of vce level Slowdown monitoring circuit;
After described energising, three-phase electricity obtains unidirectional current by rectifier circuit rectifies, then supplies resonance circuit, by mcu controller Send drive signal to drive circuit thus controlling the break-make of igbt circuit, described resonance circuit is connected with igbt circuit, described The concrete connection of zero cross detection circuit, its outfan is connected with mcu controller;
Described vce level sensitive circuit is connected with the two ends of igbt circuit, and its outfan is connected with mcu controller;
Its method specifically comprises the following steps that
Step one electromagnetic oven is energized, and starts working;
Step 2 detection electromagnetic oven whether have pan, if it has, mcu controller then the concrete material according to pan and size are searched Rope minimum duty cycle;
Particularly as follows: mcu controller provides a preliminary dutyfactor value, drive igbt circuit;
After zero cross detection circuit detects drum zero passage, start vce level sensitive circuit detection igbt both end voltage, when detection When vce is not less than setting value, then the dutycycle that mcu controller is given is unqualified, then changes preliminary dutyfactor value, continues next time Search;
If detection vce is less than setting value, preliminary dutyfactor value is qualified, this value is set to the minimum duty under current working Than;
When user selects electromagnetic oven low power run, electromagnetic oven combines step 3 according to minimum duty cycle value obtained above The actual given operating power of user adopts burst length complete cycle ratio control mode.
2. method according to claim 1 is specially linear change it is characterised in that changing preliminary dutyfactor value, including Linearly increasing or linear minimizing.
3. method according to claim 1 is it is characterised in that described burst length complete cycle ratio control mode is concrete For:
Because dutycycle is proportional with the power of electromagnetic oven, then minimum duty cycle corresponds to operating power p1;
When the power p2 that user selects is less than power p1, then the output duty cycle of mcu controller is minimum duty cycle value, now Operating frequency p1 is divided according to equal proportion, mcu controller sets the continuous control that power frequency period realizes power p2.
4. method according to claim 1 is it is characterised in that it is impossible to be less than minimum duty cycle during electromagnetic oven normal work.
CN201610909036.0A 2016-10-18 2016-10-18 Soft switch detection and temperature control method of induction cooker CN106358328A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
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Application Number Priority Date Filing Date Title
CN201610909036.0A CN106358328A (en) 2016-10-18 2016-10-18 Soft switch detection and temperature control method of induction cooker

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107124106A (en) * 2017-05-23 2017-09-01 广东工业大学 A kind of mixing control method and device suitable for two-way DC DC converters

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN201001206Y (en) * 2007-01-29 2008-01-02 深圳市鑫汇科电子有限公司 Electromagnetic furnace circuit for implementing steadily low power heating
CN101326856A (en) * 2005-10-14 2008-12-17 E.G.O.电气设备制造股份有限公司 Induction heating device and corresponding operating and pot detection method
CN201323669Y (en) * 2008-11-28 2009-10-07 佛山市顺德区瑞德电子实业有限公司 Control device of continuous heating during low power period of electromagnetic oven
CN204259199U (en) * 2014-12-16 2015-04-08 佛山市顺德区美的电热电器制造有限公司 Electromagnetic Heating control circuit, electromagnetic heater and electromagnetic oven
CN105682273A (en) * 2016-03-31 2016-06-15 杭州信多达电器有限公司 Electromagnetic heating soft start structure and starting method thereof
CN205430652U (en) * 2016-02-02 2016-08-03 佛山市顺德区美的电热电器制造有限公司 Electromagnetic?heating?device and heating control circuit thereof

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101326856A (en) * 2005-10-14 2008-12-17 E.G.O.电气设备制造股份有限公司 Induction heating device and corresponding operating and pot detection method
CN201001206Y (en) * 2007-01-29 2008-01-02 深圳市鑫汇科电子有限公司 Electromagnetic furnace circuit for implementing steadily low power heating
CN201323669Y (en) * 2008-11-28 2009-10-07 佛山市顺德区瑞德电子实业有限公司 Control device of continuous heating during low power period of electromagnetic oven
CN204259199U (en) * 2014-12-16 2015-04-08 佛山市顺德区美的电热电器制造有限公司 Electromagnetic Heating control circuit, electromagnetic heater and electromagnetic oven
CN205430652U (en) * 2016-02-02 2016-08-03 佛山市顺德区美的电热电器制造有限公司 Electromagnetic?heating?device and heating control circuit thereof
CN105682273A (en) * 2016-03-31 2016-06-15 杭州信多达电器有限公司 Electromagnetic heating soft start structure and starting method thereof

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107124106A (en) * 2017-05-23 2017-09-01 广东工业大学 A kind of mixing control method and device suitable for two-way DC DC converters

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