CN1172229A - Microwave oven equipped with thermopile sensor and thawing method using the same - Google Patents
Microwave oven equipped with thermopile sensor and thawing method using the same Download PDFInfo
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- CN1172229A CN1172229A CN97112111A CN97112111A CN1172229A CN 1172229 A CN1172229 A CN 1172229A CN 97112111 A CN97112111 A CN 97112111A CN 97112111 A CN97112111 A CN 97112111A CN 1172229 A CN1172229 A CN 1172229A
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B6/00—Heating by electric, magnetic or electromagnetic fields
- H05B6/64—Heating using microwaves
- H05B6/66—Circuits
- H05B6/68—Circuits for monitoring or control
- H05B6/688—Circuits for monitoring or control for thawing
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B6/00—Heating by electric, magnetic or electromagnetic fields
- H05B6/64—Heating using microwaves
- H05B6/6447—Method of operation or details of the microwave heating apparatus related to the use of detectors or sensors
- H05B6/645—Method of operation or details of the microwave heating apparatus related to the use of detectors or sensors using temperature sensors
Abstract
The invention relates to an improved micro-wave oven provided with a thermocouple sensor and a method for utilizing the micro-wave oven to defrost so as to lead the micro-wave oven to be able to detect the surface temperature of food through the thermocouple sensor; and thereby acquiring the best defrosting condition and remarkably reducing the defrosting time according to the detected surface temperature of food, the side of food, the output of a weight optimized permatron and the confirmed best defrosting time.
Description
The present invention relates to a kind of defreezing method that is equipped with the micro-wave oven of thermocouple sensor and utilizes this micro-wave oven, particularly a kind of improved defreezing method that is equipped with the micro-wave oven of thermocouple sensor and utilizes this micro-wave oven, by utilizing a thermocouple sensor to make it possible to detect the surface temperature of food, according to the food surface temperature that detects, the output of the size of food and the Weight-optimised magnetron of food, with definite best thawing the deadline, therefore obtained best thawing condition and reduced thawing time significantly.
Fig. 1 has shown a kind of structure of existing micro-wave oven.
As shown in the figure, existing micro-wave oven comprises that is arranged on heating clamber 20 central parts, be used for placing the turntable 30 of frozen food, one provides the magnetron 27 of microwave with the frozen food that thaws by the doping waveguide to food, a turntable motor 29 that is used to rotate turntable 30, one is arranged on heating clamber 20 sides top, be used to detect the frozen food temperature and the voltage transition that provides is the thermocouple sensor 21 corresponding to the voltage of detected temperatures, one is used for heating clamber 20 backlighted electric lights 32, a cooling fan 28 that is used to cool off magnetron 27, a voltage that is used to receive from thermocouple sensor 21, determine thawing time and to the microcomputer 22 of the control element of micro-wave oven output control signal, and according to control signal connection/cut-out electric light 32 from microcomputer 22, magnetron 27, the gauge tap 23 to 26 of cooling fan 28 and turntable motor 29.In addition, also has a weight sensor that is connected in the turntable motor shaft, is used for weighing frozen food weight.
With reference now to Fig. 1 to Fig. 4 C, explains the operation of thawing of the frozen food that utilizes existing micro-wave oven.
As shown in Figure 1, frozen food 31 is placed on the turntable 30 that is arranged in the heating clamber 20, and the Qianmen is closed.After this, when selecting to thaw switch, microcomputer is distinguished defrost mode, and carries out operation as shown in Figure 3.
At first, microcomputer 22 is connected switch 23 to 26 to drive magnetron 27, cooling fan 28, turntable motor 29 and electric light 32 in step S1.
Turntable motor 29 rotates turntable 30.
In step S2, when turntable 30 was rotated, microcomputer 22 utilized the weight sensor that is connected in the turntable motor shaft to measure the weight of frozen food 31.
In step S3, the time that turntable 30 rotates a circle is to utilize the one-period time T o of power supply and the counting P of turntable motor 29 to calculate.
Q＝(1/T0)/P
Be hypothesis P=5 in the prior art, T0=20 millisecond and Q=10 calculate second.
After the calculating of the time that the rotates a circle Q of the turntable 29 in step S3 is finished, and in step S4 through after 250 milliseconds, microcomputer 22 control systems in step S5 make magnetron 27 export 0 watt as shown in Figure 2, the power output of 300 watts and 600 watts.
Output-controlled when magnetron 27, and when step S6 closes magnetron 27, receive voltage from thermocouple sensor 21, and in step S7, calculate the voltage V that is directly proportional with the temperature of frozen food 31 according to following formula.
V＝R*(V1－V3)＋S*V2＋T
Wherein V1 represents the voltage that obtains by the output of amplifying thermocouple sensor 21, and V2 represents the voltage of thermocouple sensor, and V3 represents the reference voltage of thermocouple sensor, R, and S and T represent coefficient.
Calculate after the voltage V corresponding to the temperature of frozen food 31, in step S8, detect the time that rotates a circle (Q second) of turntable 30 and whether pass by.The result finishes the measurement to the weight W of frozen food 31 when the time that rotates a circle (Q second) past tense of turntable 30 in step S9.
In magnetron 27 closing state, when when turntable 30 rotates a circle, measuring the weight W of frozen food 31, calculate the time T 1 of 600 watts of power of magnetron 27 outputs at step S10.
T1＝0.06*W
Although thermocouple sensor 21 does not detect the completion status of thawing, in step S10 and S11, calculate the timing (TLmax that the operation of thawing is finished, after this being called maximum thaws the deadline) and the heating of magnetron stop regularly (after this TLmin is called minimum and thaws the deadline).
TLmax＝2*W
TLmin＝1*W
When obtain minimum and maximum finish regularly TLmax and TLmin after, flow process is returned step S4, and carries out the operation of step S4 to S8.
In addition, in step S8, after the rotational time (Q second) in two weeks of rotation of in step S11, having passed through turntable 30, in step S12 and S13, detect thawing time and whether thaw between the deadline TLmax in thaw deadline TLmin and maximum of minimum.
If testing result is operating time of thawing to have surpassed minimum deadline TLmin and the maximum deadline TLmax that thaws, conclude that so operation is to thaw to finish.If testing result is operating time of thawing to have surpassed the minimum deadline TLmin that thaws, but surpass the maximum deadline TLmax that thaws, so in step S14 and S15 with following formula calculated value L and M.
L＝min/ave
M＝dV/dt
Wherein min represents the minimum voltage value that obtains in turntable rotates a circle process, and ave represents mean value, and dV/dt representative voltage V is with respect to the value of the differential calculation acquisition of time.
Value L is the evaluation of estimate that is used for calculating the variable quantity of the voltage data of measuring in turntable 30 processes of rotating a circle, and the M representative is used to judge the value whether temperature of food is promptly raise.
Shown value L among Fig. 4 A.Fig. 4 B has shown the value under the heavy load situation, Fig. 4 C shown when temperature between the upper and lower part of infra-red range, i.e. value L under little loading condition.
Therefore, value L and reference value 0.094 relatively, reference value 0.094 is used for judging and is surpassing the minimum deadline TLmin but surpass the thaw variable quantity of voltage data of deadline TLmax state of maximum of thawing in step S14.
If result relatively be value L less than reference value 0.094, owing to this represents that this value is within the ultrared scope like that shown in Fig. 4 C, so decision operation is to thaw to finish.
In addition, if value L is greater than reference value 0.094, because this represents that this value is equivalent to the appropriate load shown in Fig. 4 A and the 4B or than heavy load, the size and the reference value 10 that will be worth M so in step S15 compare, so that select one in two values.
As a result, M on duty is during less than reference value 10, and this load is judged as the load that the temperature that do not make the food core increases.Therefore, when time arrival maximum was thawed deadline TLmax, the operation of thawing was finished.
In addition, if be worth M greater than reference value 10, this load is judged as the load of the temperature increase that makes the food core.Therefore, conclude thaw the operation finish.
In the defreezing method for frozen food, the surface temperature of food 31 is measured with thermocouple sensor 21.The output of magnetron 27 is to control according to the time that the weight W of measuring frozen food with weight sensor obtains.Therefore, determined the deadline of thawing.
Be directly proportional with frozen food weight W that weight sensor is measured the T1=0.06W that sets in the time with high power output (600 watts) heated food.After this rotating a circle at turntable 30 provides 300 watts voltage in time of (Q second), and does not provide 300 watts voltage in the time of rotate a circle at turntable 30 subsequently (Q second).
But, in the prior art,, therefore increased the cost of making and safeguarding owing to, when the output of control magnetron, used weight sensor in order to use high voltage frozen food T1 heat time heating time.In addition, when thawing with 300 watts voltage after the time T1 frozen food a large amount of, the time that needs to grow just can reach the deadline of thawing.In addition, be very strong owing to compare the output of magnetron with less load, so food may be locally heated.The excessive in addition operation of thawing may make frozen food heat unevenly.
If departing from middle heart, the food of the cooking is placed on the turntable weight of weighing food, thereby the operation that leads to errors so mistakenly.
Therefore, an object of the present invention is to provide a kind of improved micro-wave oven that is equipped with thermocouple sensor and a kind of defreezing method that utilizes this micro-wave oven that has overcome the above-mentioned problem that runs in the prior art.
Another object of the present invention is that a kind of improved micro-wave oven and a kind of defreezing method that utilizes this micro-wave oven that is equipped with thermocouple sensor will be provided, it can read the data from thermocouple sensor, and control the output of magnetron continuously according to the data that read, thereby from the best power output of magnetron output, and needn't consider the size and the weight thereof of food.
A further object of the present invention is that a kind of improved micro-wave oven and a kind of defreezing method that utilizes this micro-wave oven that is equipped with thermocouple sensor will be provided, it can be according to judging that from the data of thermocouple sensor food surface is liquid food surface transformation time from the state-transition of freezing, and frozen food quickly therefore can thaw.
Further aim of the present invention is that a kind of improved micro-wave oven and a kind of defreezing method that utilizes this micro-wave oven that is equipped with thermocouple sensor will be provided, the value that the variation of temperature amount of measuring when it can utilize to rotate a circle according to turntable and the offset of load (food) change is determined the deadline of thawing, thereby can obtain the optimum operating condition of thawing.
A further object of the invention is that a kind of improved micro-wave oven and a kind of defreezing method that utilizes this micro-wave oven that is equipped with thermocouple sensor will be provided, it can utilize a thermocouple sensor to detect the food surface temperature, and according to the food surface temperature of measuring, the size of food and the output of Weight-optimised magnetron thereof, thaw the deadline with definite optimum, thereby can obtain best thawing condition and reduce thawing time significantly.
For finishing above-mentioned purpose, a kind of micro-wave oven that is equipped with a thermocouple sensor is provided, it comprises a microcomputer, this microcomputer comprises that one is used for reading voltage signal sampling unit from the data signal of A/D converter at each time ts, one is used for the voltage signal in each voltage time sampling is converted to a temperature T, elimination is from the noise of the temperature T of conversion, and be the maximum of T max that a magnetron connection/cut-out cycle (tm) Time Calculation goes out a temperature, a minimum of a value Tmin, voltage signal processing unit with a mean value Tmean, one is used at the maximum of T max of a magnetron connection/cut-out cycle extraction about this temperature T, minimum of a value Tmin, temperature data sampling unit with mean value Tmean sample, one is used to utilize data that the temperature data sampling unit extracts to go out optimal magnetron connection/break time a magnetron connection/cut-out computation of Period, feasible the thawing of deadline of determining to thaw operates in the Best Times termination, calculate and the abnormal operation judging unit with the magnetron ratio of operating turn-on time that when determining to have abnormal operation, stops thawing by the state of judging food, with one be used for according to calculating from magnetron ratio turn-on time and the output of abnormal operation judging unit is exported a control signal to magnetron connection/cut-out switch, and the magnetron connection/cut-out on-off controller of the output of control magnetron, the micro-wave oven that wherein is equipped with a thermocouple comprises a ultrared light collecting device that is used to assemble from food, one is used to produce one corresponding to the transducer module (thermocouple sensor) from the ultrared voltage of light collecting device, one is used for the amplifier that is amplified to a predetermined level from the output voltage of transducer module, one is used for the A/D converter that is converted to a digital voltage signal from the voltage signal of amplifier, with a voltage signal that is used to handle from A/D converter, algorithm control magnetron connections/the cut-outs switch of the thaw routine that provides according to relevant inside and control the microcomputer that is placed on the energy of the food the heating clamber from the magnetron supply.
For finishing above-mentioned purpose, provide a kind of utilization to be equipped with the defreezing method of the micro-wave oven of thermocouple type sensor, the first step of the initial temperature T of it may further comprise the steps: one is cut off a period of time with magnetron---this time was obtained by a combination time that turntable rotates a circle when key signals is thawed in input and a response time before the turntable normal rotation---and detection food, one is utilized digital filter that the temperature T that detects in first step is filtered into Tf, and be that the temperature T f relevant for this filtration in a magnetron connection/cut-out cycle calculates a maximum of T max, second step of a minimum of a value Tmin and a mean value Tmean, one judges whether that a magnetron connection/cut-out cycle is over and done with, when judging but the result does not also have past tense to return first and second steps in this magnetron connection/cut-out cycle, filter the third step that this maximum of T max calculates a filter value Tmaxf with utilizing when the magnetron connection/cut-out period expires, a changing value Δ Tmaxf who calculates the filter value Tmaxf of the maximum of T max in the third step, and judge the 4th step of the recruitment of this value, one is calculated an additional thawing time ta when this changing value Δ Tmaxf increases in the 4th step, determine the deadline of thawing, calculate magnetron ratio turn-on time, and when not increasing, calculates changing value Δ Tmaxf the 5th step of magnetron ratio turn-on time, one is utilized magnetron ratio turn-on time, with mean value Tmean, and current time of passing judge the 6th step of the abnormality of the mode of operation of the algorithm that thaws and food, with the 7th step of when decision operation is abnormality in the 6th step, thaws and operating and when decision operation is not abnormality, turn back to first step by the termination of cut-out magnetron.
For finishing above-mentioned purpose, provide a kind of utilization to be equipped with the defreezing method of the micro-wave oven of a thermocouple type sensor according to another embodiment of the invention, it may further comprise the steps: the rotate a circle first step of measurement variation of temperature amount of time of calculating turntable, second step of calculating a basis corresponding to the value Kd of the offset variation of the variable quantity that calculates in the first step, one by a temperature value---this temperature value be the Current Temperatures by the load in each magnetron connection/cut-out cycle (tm) deduct initial temperature obtain---multiply by the different weights value and calculates the third step of magnetron ratio turn-on time P and one and stopping the 4th step of thawing and operating when obtaining this value with a load temperature variable quantity of measuring in each magnetron connection/cut-out cycle (tm) Kd is on duty.
From the following description, can more clearly understand other advantage, purpose and feature of the present invention.
Will understanding more fully be arranged to the present invention by following detailed description that provides and accompanying drawing, accompanying drawing only is to provide in the mode that illustrates, does not therefore limit the present invention, wherein:
Fig. 1 is the block diagram that shows a kind of existing microwave oven;
Fig. 2 is the oscillogram of magnetron output control signal of frozen food of thawing in this existing micro-wave oven;
Fig. 3 is the flow chart of an existing method of defreezing by microwave oven of explanation;
Fig. 4 A to 4C is the curve map as the frozen food duration L that thaws in existing micro-wave oven, wherein:
Fig. 4 A is the curve map that shows as the appropriate duration L of load;
Fig. 4 B is the curve map that shows as high capacity duration L;
Fig. 4 C is the curve map that shows as low load duration L;
Fig. 5 is that explanation is according to the block diagram that has the micro-wave oven of a thermocouple sensor of the present invention;
Fig. 6 A and 6B are presented at the food that will cook and one to be installed in key diagram according to the opereating specification between the transducer module on the heating clamber top of micro-wave oven of the present invention;
Fig. 7 is the block diagram that shows the micro-wave oven that has a thermocouple sensor according to another embodiment of the invention;
Fig. 8 A and 8B are presented at the food that will cook and a key diagram that is installed in according to the opereating specification between the transducer module on heating clamber of the present invention top;
Fig. 9 A and 9B show when the curve map of the surface temperature variation of food during defrosting food according to the present invention;
Figure 10 A shows the surface temperature variation of food when food is placed on the core of turntable according to the present invention and the curve map of the correlation between rate of change;
The curve map of the correlation when Figure 10 B is a side that shows when the core that food is placed on turntable according to the present invention between the surface temperature variation of food and the rate of change;
Figure 10 C and 10D shown according to the thawing condition between a little food of the present invention and the big food, and when correlation be according to the thawing condition when the maximum value calculation in each magnetron connection/cut-out cycle is come out;
Figure 11 has shown the curve map that relies on the food surface temperature change according to magnetron of the present invention ratio turn-on time P;
Figure 12 shows that magnetron connections/cut-outs control the oscillogram of exporting, and wherein tm is a constant magnetron connection/cut-out cycle, and magnetron changes connection/break time;
Figure 13 is the oscillogram that shows magnetron connection/cut-out control output, and wherein be constant the turn-on time of magnetron, and magnetron connection/cut-out cycle tm changes;
Figure 14 is the block component diagram that shows according to the microcomputer in the micro-wave oven of Fig. 5 of the present invention;
Figure 15 has shown according to variations in temperature of the present invention with relevant for the maximum of temperature, the temperature variation characteristic of mean value and minimum of a value;
Figure 16 has shown the curve map according to additional thawing time example calculation of the present invention;
Figure 17 is the flow chart that shows according to the defreezing method of the micro-wave oven that utilizes a thermocouple sensor of the present invention;
Figure 18 is the timing diagram when a defrost mode finishes;
Figure 19 be show according to of the present invention be constant when the magnetron connection/cut-out cycle, and magnetron turn-on time the automatic defreezing method in the micro-wave oven of Figure 14 when being different key diagram;
Figure 20 A to 20D is that its intermediate value Tmaxf obtains by the maximum of T max that leaches relevant temperature according to the curve map of the rate temperature change of the changing value Δ Tmaxf about value Tmaxf of the present invention;
Figure 21 is the flow chart of the method for the increase of judgment value Δ Tmaxf in the micro-wave oven of Figure 17;
Figure 22 be show according to of the present invention for identical electric loading offset and the curve map of the correlation between the variations in temperature of measurement;
Figure 23 is the curve map that shows according to the correlation between the variable quantity of the offset of electric loading of the present invention and acquisition when turntable rotates;
Figure 24 is the curve map that shows according to correlation between the value of variable quantity of the present invention and Kd;
Figure 25 is the flow chart according to the defreezing method of the micro-wave oven that utilizes a thermocouple sensor of the present invention;
Fig. 5 to 13 has shown according to a microwave oven structure that is equipped with a thermocouple sensor of the present invention.
As shown in the figure, the micro-wave oven that is equipped with a thermocouple sensor according to the present invention comprises a ultrared light focusing unit that is used to assemble from food 10, one is used to produce corresponding to from the light focusing unit infrared ray with from the transducer module 2 of the ultrared voltage of turntable 9, one is used for the amplifier 3 that is amplified to a predetermined level from the output voltage of transducer module 2, one is used for the A/D converter 4 that is converted to digital voltage signal from the voltage signal of amplifier 3, with a voltage signal that is used to handle from A/D converter 4, according to a microcomputer 5 of supplying with the energy that is placed on the food 10 in the heating clamber 1 based on the magnetron connection/cut-out switch 6 of algorithm control and the control magnetron of thaw routine.
Microcomputer 5 comprises that one is used for reading voltage signal sampling unit 51 from the data signal of A/D converter 4 at each time ts, one is used for the voltage signal in each voltage time sampling is converted to temperature T, elimination is included in the noise in the temperature T of conversion, and the maximum of T max of the temperature of output magnetron connection/cut-out cycle tm, the voltage signal processing unit 52 of minimum of a value Tmin and mean value Tmean, a maximum of T max who is used for extracting relevant temperature T in each magnetron connection/cut-out cycle, the temperature data sampling unit 53 of minimum of a value Tmin and mean value Tmean, one is used to utilize data computation that the temperature data sampling unit extracts optimal magnetron connection/break time in each magnetron connection/cut-out cycle, determine to make to thaw and operate in thawing that Best Times finishes and finish regularly, whether judgement exists abnormality in food, if and judged result be exist abnormality to stop thawing magnetron ratio turn-on time of operation calculates and abnormal operation judging unit 54 and one are used for according to calculating from magnetron ratio turn-on time and the magnetron connection/cut-out on-off controller 55 of a control signal is exported in the output of abnormal operation judging unit 54 to magnetron connection/cut-out switch 6.
The algorithm that native system comprises has: one is used for the algorithm that is converted to temperature T at the voltage signal of each time sample, a digital filter algorithm that is used for eliminating the noise that is included in temperature T, a maximum value calculation algorithm that is used to calculate the maximum of T max of magnetron connection/cut-out cycle tm, the minimum of a value computational algorithm of the minimum of a value Tmin of a temperature that is used to calculate magnetron connection/cut-out cycle tm and one are used to calculate the mean value calculation algorithm of mean value of the temperature of magnetron connection/cut-out cycle tm.
In addition, the defreezing method of the micro-wave oven of thermocouple sensor that utilizes according to the present invention comprises: one is cut off a period of time with magnetron---be during this period of time be used in the time that the turntable of the incipient stage of the operation of thawing rotates a circle add that the rotation response time before the turntable normal rotation obtains---, first step with the initial temperature T that detects food, one is utilized digital filter that the temperature T that detects in first step is filtered into temperature T f, with the maximum of T max that calculates magnetron about the temperature T f that filters, second step of minimum of a value Tmin and mean value Tmean, judge whether the magnetron connection/cut-out cycle go over for one, if the cycle is not carried out first second step in the past, and utilize this maximum of T of filtration max to calculate the third step of filtration value Tmaxf, the changing value Δ Tmaxf of the filtration value Tmaxf of the maximum of T max of calculating in third step, and judge that it increases the 4th step of state, one calculates an additional thawing time ta when changing value Δ Tmaxf increases in the 4th step, determine to thaw and finish regularly, calculate magnetron ratio turn-on time, and when not increasing, changing value Δ Tmaxf calculates the 5th step of magnetron ratio turn-on time, one is utilized magnetron ratio turn-on time, mean value Tmean and the time that passes before the current time are judged the 6th step of the abnormal operation state of the algorithm that thaws, with one when in the 6th step, judging when having abnormal operation by cutting off magnetron stop thawing operation and just often turn back to the 7th step of first step when mode of operation.
Explanation is about the increase state of the changing value Δ Tmaxf of the filtration value Tmaxf of the maximum of T max in the 4th step now.
When current when passing time tr, relatively the currency Δ Tmaxf (tr) of Δ Tmaxf and the value Δ Tmaxf (tr-tm) of value Δ Tmaxf before time T m less than three magnetron connection/cut-out cycles (3*tm).If comparative result be value Δ Tmaxf (tr) greater than value Δ Tmaxf (tr-tm), the value of concluding Δ Tmaxf has increased so, if value Δ Tmaxf is worth less than this, the value of concluding Δ Tmaxf does not increase so.
In addition, explanation now is about the increase state of the changing value Δ Tmaxf of the filtration value Tmaxf of the maximum of T max in the 4th step.
When current when passing time tr, the currency Δ Tmaxf (tr) of Δ Tmaxf and the value Δ Tmaxf (tx-tm) and Δ Tmaxf (tr-2*tm) comparison of value Δ Tmaxf before time tm and time 2*tm greater than three magnetron connection/cut-out cycles (3*tm).If comparative result be value Δ Tmaxf (tr) greater than value Δ Tmaxf (tr-tm), or the value Δ Tmaxf (tr) greater than the value Δ Tmaxf (tr-2*tm)+δ (positive number) greater than 0, the value of concluding Δ Tmaxf has increased so.In other situation, conclude that this value does not increase.
As shown in figure 25, the defreezing method that is equipped with the micro-wave oven of thermocouple sensor according to the present invention comprises: a first step of measuring the variation of temperature amount in starting stage calculating turntable rotates a circle process, second step of the offset calculated value Kd of the variable quantity coupling of calculating in basis and the first step, the temperature value that handle is relevant---this temperature value is that the initial temperature that the Current Temperatures that is used in each magnetron connection/cut-out cycle tm deducts load obtains---multiply by the different weights value so that calculate the third step of magnetron ratio turn-on time P, during less than constant value Dr, stop the 4th step of thawing and operating with one---this value be used in the magnetron ratio turn-on time P that obtains in the third step deduct the value that the load temperature variable quantity value of multiply by Kd of measuring at each magnetron connection/cut-out cycle tm obtains obtain---on duty.
With reference now to description of drawings, according to the operation that is equipped with the micro-wave oven of thermocouple sensor and utilizes the method for this defreezing by microwave oven of the present invention.
At first, as shown in Figure 5, the frozen food 10 that thaw is placed on the turntable 9 that is arranged in the heating clamber 1, and press the key (not shown) that thaws, microcomputer 5 is distinguished above-mentioned operation, drives signal to one of turntable motor 8 output then, and connects magnetron connection/cut-out switch 5.
After this, when turntable motor 8 rotated turntable 9 and connect magnetron connection/cut-out switch 5, magnetron 7 was excited, and to the frozen food 10 output microwaves that are placed on the turntable 9, thereby frozen food 10 is thawed.
The light focusing unit of transducer module 2 is focused at the infrared ray that produces in the operating process of thawing, and sends it to thermocouple sensor.Thermocouple sensor is converted to a voltage to the infrared ray of assembling, and this voltage is outputed to amplifier 3.
Light focusing unit comprises convex lens or a concave mirror, makes the visual field of thermocouple sensor narrow down and improves the output voltage of thermocouple sensor.
As shown in Figure 5, can transducer module 2 downward-sloping predetermined angles be made to divide from the upper lateral part of heating clamber 1 to monitor turntable 9, and as shown in Figure 7, can depart from the core of heating clamber 1 at this.Therefore, can measure the temperature of the core and the lateral parts of turntable 9.
Explanation now is placed on the size of the food on the turntable 9 and the setting angle of transducer module 2.
Fig. 6 A and 6B have shown the transducer module 2 that is installed in heating clamber 1 side.Fig. 8 A and 8B have shown the transducer module 2 that is installed in heating clamber top.To illustrate in greater detail the setting angle of transducer module 2 later on.
A/D converter 4 is converted to digital voltage data to the analog voltage signal of the temperature of the related food that is amplified to a predetermined level, outputs to microcomputer 5 then.
Here, this magnetron connection/cut-out switch 6 comprises a delay cell, a transistor, or the like.
Therefore excite the magnetron of controlling by magnetron connections/cut-outs switch 67, and produced the microwave that covering is placed on the food 10 in the heating clamber 1.
In addition, turntable motor 8 rotates turntable 9 with preset time cycle, thereby heated food equably.
Fig. 9 A and 9B have shown food surface variation of temperature when the heats cold jelly food.
That is, the food surface variation of temperature is shown as two transition points in Fig. 9 A.In the state of the freezing food surface of maintenance, surface temperature was raising always before first transition point occurred.In addition, to second transition point, food surface is from the freezing solid-state liquid state that changes 0 degree temperature into of 0 degree temperature from first transition point.
The energy that magnetron 7 is supplied with is consumed in the transformation of above-mentioned surperficial phase state.Therefore, there is not the food surface variations in temperature.
After this, continue heated food, surperficial phase transformation has taken place.At this moment, the surface temperature of food remains on 100 ℃ temperature.
As shown in Fig. 9 B, the food surface rate temperature change slows down when phase transformation occurring, does not have variations in temperature when phase transformation occurs.Therefore, rate temperature change is 0.After this, rate temperature change is accelerated.
In the operation of the frozen food that thaws, thawing, to finish regularly be that phase transformation according to from the freezing state to the liquid state is determined the finish time.
The moment from the freezing state to the liquid state is exactly that rate temperature change is increased to moment more than 0.
But, when utilizing thermocouple sensor actual measurement food surface temperature, the rate temperature change shown in Fig. 9 A and the 9B than Figure 10 A to the rate temperature change height shown in the 10D.
That is to say that when the phase transformation of carrying out from the freezing state to the liquid state, not having variations in temperature is desirable requirement.As shown in Figure 10 A and 10D, the temperature of measuring in the transformation time interval has raise.
As shown in Fig. 6 A to 8B, above-mentioned increase is because the visual field of thermocouple sensor and the size of food cause.
Fig. 6 A and 6B have shown the correlation between the visual field and food size when thermocouple sensor is installed in the upper lateral part of heating clamber 1.Because when food is enough big, have only the infrared ray that produces from food surface to project on the thermocouple sensor, what show among Fig. 9 A and the 9B is the food surface temperature.
As shown in Fig. 6 B, when food hour, the infrared ray that infrared ray that food produces and turntable 9 produce all projects on the thermocouple sensor.
Therefore, obtained the characteristic of the food surface variations in temperature as shown in Figure 10 A to 10D.
Fig. 8 A and 8B have shown the correlation between the visual field and food size when thermocouple sensor is installed in the top of heating clamber 1.Shown in Fig. 8 A, when food was enough big, only the infrared ray from food surface projected on the thermocouple sensor.Therefore, obtained the characteristic of food surface variations in temperature as shown in Figure 9A and 9B.
In addition, as shown in Fig. 8 B, when food hour, all project on the thermocouple sensor from the infrared ray of food and from the infrared ray of turntable 9.
Therefore, obtain the characteristic that the food temperature as shown in Figure 10 A to 10D changes.
As a result, rely on according to the food surface temperature and judge the size of food indirectly and can avoid the local excessive of food to thaw and thaw deficiency according to the output that the size of food is suitably controlled magnetron.
In addition, as shown in Figure 10 A to 10D, when the moment that the freezing state of food surface changes liquid state into, the temperature that little food is measured is higher than the temperature that big food is measured.
Magnetron is for being longer than big food the heat time heating time of pot foods.Utilize the measurement temperature of thermocouple sensor, can determine optimal magnetron output according to the size of food.
The processing procedure of magnetron output is determined in explanation now.
Suppose that magnetron ratio turn-on time is P, and the food surface temperature is T, can determines magnetron ratio turn-on time P with following equation (1) so.
P＝f(T)………(1)
Suppose that magnetron turn-on time is ton, and magnetron break time be toff, obtained equation P=ton/ (ton+toff) so.F (T) representative can be expressed as one about the linear equation form of temperature T or the function of non-linear form, supposes that magnetron connection/cut-out cycle tm is a constant.
According to equation (1), because magnetron connection/cut-out cycle tm is a constant, so temperature T is to calculate at predetermined cycle tm.
Therefore, calculate magnetron ratio turn-on time P again at a magnetron connection/cut-out cycle tm, and change it subsequently.
For example, when area of heating surface temperature as shown in Figure 10 A to 10D is approximately-5 ℃ little and big food, suppose that magnetron ratio turn-on time for big food is 80% (for example, magnetron was connected 8 seconds, with cut-out 2 seconds) be optimum state, pot foods must (for example, 60%) heating under less than magnetron ratio turn-on time of magnetron ratio turn-on time of larger food, thereby has prevented to cross and thaw.
Therefore, determine that like this magnetron ratio turn-on time P makes ratio P and food surface temperature be inversely proportional to.
Magnetron ratio turn-on time is determined according to a single order ratio equation.
P＝k1*(Tr－T)……(2)
Wherein K1 represents a proportionality constant, and Tr represents a constant.
Figure 11 has shown an example of equation (2).
Because magnetron ratio turn-on time can not be greater than 1, temperature T is less than-5 ℃, so P=1.
Because the calculating according to the magnetron ratio turn-on time P of equation (2) can only be undertaken by the food surface temperature that the magnetron sensor is determined, so sensor may be damaged by various environmental factors.
In order to overcome above-mentioned problem, can calculate magnetron ratio turn-on time P with the linear equation that adds rate temperature change.
P＝K1*(Tr－T)＋k2*ΔT………(3)
Wherein Δ T represents the changing value of food surface temperature in the unit interval.For example, if the magnetron connection/cut-out cycle is constant 10 seconds, Δ T represents the variation of food surface temperature in 10 second time so.
In addition, based on equation (3) and consider the initial temperature of food, can use following equation.
P＝K1*{Tr－[K2*T＋K3(T－T0)]}
＝K1*[Tr－(T－K3*T0)]……(4)
Wherein T0 represents the initial temperature of the food that thermocouple sensor measures, and (T-T0) represent poor between Current Temperatures and the initial temperature, and K2 and K3 represent the weighted value less than 1, weighted value wherein can suitably be set make it can satisfy the equation of K2+K3=1.In addition, can cancel the value of K2.
Figure 12 has shown that magnetron connection/cut-out cycle tm is that constant and magnetron connection/cut-out cycle are the examples of variable.
In equation (1), magnetron ratio turn-on time is to calculate in magnetron connection/cut-out cycle tm is the state of constant.In addition, as shown in figure 13, can calculate magnetron connection/cut-out cycle tm and control magnetron connection/rupturing operation by---keeping constant magnetron ton turn-on time when measuring the food surface temperature---according to the food surface temperature of measuring.Also can calculate magnetron connection/cut-out cycle tm and control magnetron connection/rupturing operation by---keeping constant magnetron toff break time when measuring the food surface temperature---according to the food surface temperature of measuring.
Can as following equation, utilize the magnetron ratio turn-on time P that calculates according to equation (1) to (4) to calculate magnetron connection/cut-out cycle tm.
tm＝P*ton………(5)
toff
tm＝——………(6)
P-1
Wherein, keep constant, keep constant at equation (6) intermediate value toff at equation (5) intermediate value ton.
When thawing frozen food, can utilize thermocouple sensor to determine according to the amount of food that the best is thawed and finish regularly and optimal magnetron connection/cut-out ratio P according to above-mentioned method.
That is to say, owing to can directly distinguish the processing procedure that a food surface temperature is changing, thereby can obtain best thaw and heat, and can be in the Best Times end operation of thawing.
Therefore, with reference now to Figure 14 the frozen food defreezing method is described.
That is to say that temperature T=(W1*Ts+W2*Te), this temperature is by food surface temperature T s and the temperature T e addition of weighting W1 and W2 obtain respectively in transducer module 2 measurements.
Weighted value W1 and W2 change according to the size of food and the internal temperature of heating clamber 1.
Voltage transitions after A/D converter 4 will amplify is a digital voltage signal, and the signal after will changing outputs to microcomputer 5.
Voltage signal sampling unit 51 is sampled to the digital voltage data from A/D converter 4 with the interval of regulation, and the voltage data of sampling is outputed to voltage signal processing unit 52.
Voltage signal processing unit 52 is converted to temperature to the voltage data of sampling, and removes the noise that is included in the temperature T that calculates.After this, calculate maximum about this temperature T, mean value, minimum of a value, or the like, and with its output.The temperature T that processing calculates is so that can carry out the algorithm that thaws.
That is to say a kind of algorithm that is used for the voltage signal a constant time ts sampling is converted to a temperature T of voltage signal processing unit 52 execution, a kind of digital filter algorithm that noise is removed from temperature T of being used for, a kind of maximum value calculation algorithm that is used to calculate a connection/cut-out cycle tm maximum of T max, a kind of minimum of a value computational algorithm that is used to obtain the minimum of a value Tmin of (tm) time in magnetron connection/cut-out cycle, the mean value calculation algorithm of a kind of mean value Tmean of the temperature that is used to calculate (tm) time in magnetron connection/cut-out cycle, or the like, and the temperature data that calculates outputed to temperature data sampling unit 53.
The digital filter algorithm comprises following linear equation, utilizes it to eliminate electromagnetic wave from the voltage data of sampling.
Tf(t)＝θ1
*Tf(t－ts)＋θ2
*Tf(t－2
*ts)＋，…，θn
*Tf(t－n
*ts)
ω0
*T(t)＋ω1
*T(t－ts)＋，…，＋ωm
*T(t－ts)……(7)
Wherein Tf (t) representative is at the temperature value of time t filtration, the temperature value that Tf (t-ts) representative filters at time t-ts, θ 1-θ n representative is for the weighted value that filters temperature value, T (t) representative is by the temperature value that comprises noise of sampling voltage calculated signals, and ω 0-ω m represents for the temperature value weighted value that comprises noise.
For microcomputer 5 can be relatively easy to calculate, can suppose that all values θ 1-θ n is 0, the value of ω 0-ω m all is that 1/m is with the temperature of measurement before obtaining and the mean value between the current measurement temperature.
In addition, the maximum algorithm, the minimum of a value algorithm, the mean value algorithm, or the like be used to calculate the maximum of T max of magnetron connection/cut-out cycle tm about temperature value Tf, minimum of a value Tmin, mean value Tmean, or the like.
As the temperature T f that calculate by voltage signal processing unit 52 handles, and about the maximum of temperature T f, when minimum of a value Tmin and mean value Tmean output to temperature data sampling unit 53, temperature data sampling unit 53 extracts maximum of T max, minimum of a value Tmin and mean value Tmean, and the value that will extract outputs to calculating of magnetron ratio turn-on time and abnormal operation judging unit 54.
Magnetron ratio turn-on time calculates and abnormal operation judging unit 54 utilizes temperature T f according to equation (1) to (6) and about the maximum of T max of temperature T f, minimum of a value Tmin and mean value Tmean calculating optimum magnetron connection/break time, determine that the feasible operation of thawing of additional thawing time ta can stop and judge the abnormality of food at Best Times.
Magnetron ratio turn-on time calculate and abnormal operation judging unit 54 in, can utilize temperature T f and about maximum of T max, minimum of a value Tmin and mean value Tmean calculating optimum magnetron ratio turn-on time of temperature T f according to equation (1) to (6).But,, therefore use minimum of a value Tmin because minimum of a value is identical with the mean value of food surface temperature.
That is to say that magnetron ratio turn-on time is to utilize temperature T and calculate about the minimum of a value Tmin of this temperature according to equation (1) to (6).
In addition, in calculating of magnetron ratio turn-on time and abnormal operation judging unit 54, the deadline of thawing utilizes maximum of T max to determine.
That is to say, as shown in Figure 15, can shown in Fig. 9 A, judge the operation deadline of thawing at the point (that is, second changes the point that forms) of rate temperature change increase.As shown in Figure 15, the most clearly appear in the curve of formation about this is peaked.
In calculating of magnetron ratio turn-on time and abnormal operation judging unit 54, the calculating of additional thawing time utilizes time tc to carry out, second transition point in the curve map of the relevant temperature transition of this time tc, occurred, also can be used for same purpose to temperature T c at the food of this time tc.Can distribute a predetermined additional thawing time at time tc, and needn't consider the amount of food.
The time tc and the linear equation below the food temperature Tc of this time passes through that can utilize second transition point to form calculate additional thawing time ta.
ta＝C1*tc＋C2………..(8)
ta＝C3*Tc＋C4………..(9)
C1 wherein, C2, C3 and C4 represent constant.
Figure 16 has shown the example about equation (8) and (9).
In addition, magnetron ratio turn-on time calculate and abnormal operation judging unit 54 in, the state of food is with mean value Tmean judgement, because mean value is indicated the whole state of food more accurately, rather than maximum of T max and minimum of a value Tmin.
When judging the abnormality of food, if mean value Tmean greater than a predetermined temperature (for example, 20 ℃), because magnetron ratio turn-on time calculates and abnormality judging unit 54 may conclude that the user excessively thaws or do not have the state of food to import the key signals that thaws at food, so export a signal that cuts off magnetron 7 immediately, thereby stop thawing operation.
If judge the abnormality of food with maximum of T max, when food was placed on the turntable 9 prejudicially, maximum of T max may surpass 20 ℃ of temperature that are used for this magnetron connection/cut-out cycle time.
Therefore, the operation of thawing may stop in frozen food thaws not enough state.
In addition, if judge the abnormality of food with minimum of a value Tmin, since very little at the latter temperature variable quantity of the operation of thawing, thereby need long time very unfriendly, make minimum of a value can not surpass 20 ℃ temperature.
Can come calculating mean value Tmean with simple arithmetic mean of instantaneous value.In addition, in order more easily to calculate, can use the value of (Tmax+Tmin)/2.
In addition, magnetron ratio turn-on time calculates and abnormality judging unit 54 utilizes magnetron ratio turn-on time and the time that passes before current time to judge the abnormal operation of the algorithm that thaws.If judged result is to have the abnormal operation state, magnetron ratio turn-on time calculates and abnormality judging unit 54 is exported a signal to stop thawing operation to magnetron connection/cut-out switch.
If magnetron ratio turn-on time is calculated in as shown in Figure 11 such, and the value that calculates is concluded that so the algorithm fails of thawing arrives the transition point of temperature variation curve, thereby is stopped thawing operation less than 0.2.
The transition point that rate temperature change increases appears to measure when temperature is lower than 10 ℃ and occurs.When temperature was 10 ℃, magnetron ratio turn-on time was 0.5 (15-10)=0.25.When currency was 0.2, current minimum temperature was 11 ℃.Therefore, its expression has surpassed transition point.
In addition, less at current magnetron ratio turn-on time, and when after the operation of the algorithm that thaws, having passed the long time, judge that the algorithm that thaws can not arrive the transition point of temperature curve, therefore stop thawing operation.
As shown in figure 11, when magnetron ratio turn-on time is 0.3, and pass by five minutes after the algorithm that thaws, this operation of thawing is terminated.
As shown in figure 14, finish the result of judgement according to magnetron ratio turn-on time that magnetron ratio turn-on time calculates and abnormal operation judging unit 54 calculates and the operation of thawing, magnetron connection/cut-out on-off controller 5 is exported a connection/shutoff signal to magnetron connection/cut-out switch 6.
6 operations according to connection/cut-out gauge tap of magnetron connection/cut-out switch switch on or off magnetron.
Figure 17 has shown the defreezing method that is equipped with the micro-wave oven of thermocouple sensor according to of the present invention.
With reference now to description of drawings, according to defreezing method of the present invention.
At first, thaw during key signals the variable of initialization execution algorithm when what a user imported the frozen food that thaws.That is, in step S100, replace variable ti with 0.
After initialization of variable, magnetron is cut off one section zero-time tp, measure the initial temperature of food 10 then.
Here time tp adds the turntable motor 8 normal rotation rotation response time before time that turntable 9 rotates a circle.
If the time that turntable 9 rotates a week is 10 seconds, the rotation response time of turntable motor 8 is 3 seconds, and time tp is 13 seconds so.
In step S101, calculate the time t of the operation of thawing continuously, and whether the sample time ts of detectable voltage signals goes over.
In step S101, in step S102, calculate the value of tr=t-tp in the past after sample time ts.After this, the value that in step S103, compares tr and tc+ta.
If result relatively is the value of tr value greater than tc+ta, cut off magnetron 7, therefore in step S104, stop thawing operation.If the value of tr is not more than the value of tc+ta, then in step S105, read voltage data V from A/D converter 4, be used to calculate temperature T corresponding to voltage data V.
Be worth the time that on behalf of the food surface rate temperature change, tc accelerate here, the representative of ta value is since the additional thawing time of time tc.
In step S106, with of the temperature T filtering of digital filter algorithm, thereby calculate temperature T f, and therefrom eliminate noise in step S105, calculating.
When the calculating of temperature T f finishes, in step S107, calculate the maximum of T max of (tm) time in magnetron connection/cut-out cycle, minimum of a value Tmin and mean value Tmean, and in step S108, compare the value of tr and ti+tm and judge whether magnetron connection/cut-out cycle tm goes over.
If the result who judges does not have in the past (tm) time in magnetron connection/cut-out cycle, that is,,, and repeat step S101 to S107 so to control signal of magnetron connection/cut-out switch output if value ti is different with tm.If cycle tm is over and done with in magnetron connection/cut-out, that is,, filters maximum of T max so, thereby in step S109, obtain filtration value Tmaxf about the temperature T f of food if value tr is identical with ti+tm.
At this moment obtain the mean value of Tmax (t-tm) and Tmax (t) value with following formula.
Wherein Tmax (t) represents the maximum of T max that calculates at time t.
In step S110, calculate the variation of maximum of T maxf with following formula.
ΔTmaxf(t)＝Tmaxf(t)-Tmaxf(t-tm)………..(11)
Wherein Δ Tmaxf (t) representative is in the value of the Δ Tmax of time t calculating.
After calculating peaked changing value Δ Tmax, judge in step S111 whether this changing value increases.
As shown in Figure 20 A to 20D, under various conditions---the amount of food for example, or the like---the increase of the peaked changing value Δ Tmax of filtration appears at the different time.Particularly, as shown in Figure 20 B, can not judge transition point with the increase of value Δ Tmax.
That is to say, as shown in Figure 20 B, even some B is actually transition point, may be but put A by the wrong actual transition point that is identified as, thereby make the frozen food deficiency of thawing.
In addition, as shown in Figure 20 C and 20D,,, judge that the quantity of the data of transition point is restricted because transition point appeared in the very short time if food is less.
Figure 21 has shown a transition point determination methods of avoiding the problems referred to above.
That is, tr on duty is during less than three magnetron connection/cut-out cycles (3*tm), and---it is the currency of Δ Tmaxf, and------it is the value of the Δ Tmaxf before time tm---compares with the value of Δ Tmaxf (tr-tm) the value of Δ Tmaxf (tr).If result relatively is the value of the value of Δ Tmaxf (tr) greater than Δ Tmaxf (tr-tm), judge that so the value of Δ Tmaxf has increased.If the value of Δ Tmaxf (tr), is judged the value of Δ Tmaxf so less than the value of Δ Tmaxf (tr-tm) and is not increased.
In addition, if the value of tr is greater than value 3*tm,---it is the currency of Δ Tmaxf, and------they are the values of the Δ Tmaxf before time tm and time 2*tm---compares with the value of Δ Tmaxf (tr-tm) and Δ Tmaxf (tr-2*tm) so the value of Δ Tmaxf (t).If result relatively is the value of the value of Δ Tmaxf (tr) greater than Δ Tmaxf (tr-tm), or the value of Δ Tmaxf (tr) is greater than the value of Δ Tmaxf (tr-2*tm)+δ---wherein δ represents one greater than 0 positive number---, judges that so the value of Δ Tmaxf increases.
Increase if in step S111, judge this value, in step S112, calculate additional thawing time so according to equation (8) and (9), and with current time t substitute variable tc.
Next, in step S113, calculate magnetron ratio turn-on time P according to equation (1) to (7).After this in step S114, judge whether thawing and have abnormality in algorithm or the food.
, when judging abnormality, use mean value Tmean here, magnetron ratio turn-on time P, current passing the time, or the like.
In step S114, there is abnormality if judge, cut off magnetron 7, thereby the operation that stopped thawing.If judge not have abnormality, then a control signal outputed to magnetron connection/cut-out switch 6.
Then, initializing variable, calculating the above-mentioned value of relevant new magnetron connections/cut-out cycle time (tm), and with being worth tr replacement value ti.
Therefore, by above-mentioned steps frozen food is thawed with best thawing time.
So far illustrated by switching on or off the magnetron of operation control.If a user will control magnetron by a plurality of operations, can change magnetron computational methods connection/break time with computational methods of calculating the magnetron output quantity so.
That is to say, replace the magnetron ratio turn-on time P that calculates by equation (1) to (5) with the amount of magnetron output.
Therefore, can utilize the data of measuring from thermocouple sensor, by the output quantity of control magnetron, the frozen food that in optimum state, thaws, and needn't consider the size of food, thereby shortened thawing time the biglyyest.
Determine the to thaw another kind of method of deadline of explanation now.Deadline of thawing utilizes magnetron ratio turn-on time P and temperature to advance the speed definite.
P-Kd*{T(k)-T(k-1)}≤Dr………..(12)
If satisfied aforesaid equation (12), EO thaws.
In equation (12), the temperature of the food that T (k-1) representative was measured before (tim) time in magnetron connection/cut-out cycle, Dr represents constant, the value that the offset of Kd representative dependence load (food) changes.
As 22 variations in temperature that shown the offset that depends on load (food) that thermocouple sensor is measured.
In the occasion of eccentric load, because temperature variation is very little, prolonged the deadline of thawing, therefore cause excessively and thaw.
Therefore in the occasion of eccentric load, increasing value Kd makes that the operation of thawing for little temperature variation is terminated.
For the offset of sensing lead, used the measurement variation of temperature amount A0 that in turntable rotates a circle process, obtains.
Figure 23 has shown the variation of the measurement variation of temperature amount A0 of the offset that depends on load when turntable rotates.As shown in the figure, the measurement variation of temperature amount A0 that obtains in the process of rotating a circle increases with the increase of offset.
For the value of the Kd that calculates the offset that depends on load, must obtain variable quantity A0 and depend on correlation between the value of the Kd that offset changes.In the present invention, the value of Kd utilizes look-up table to calculate from variable quantity.
For example, the value of Kd be set at one wherein variable quantity less than the K1 in the scope of the value of a constant a1 and the value of Kd be set at one wherein variable quantity greater than the K2 in the scope of the value of a constant a2.
If variable quantity between the value of a1 and a2, is arranged on the value of Kd between the value of K1 and K2 so.
With reference now to Figure 25, illustrates that the thawing of offset of determining to depend on load finish regularly and the method for variable quantity.In step S200, when key signals is thawed in input, give the initial value of the variable of the operation of thawing.
In step S201, calculate and measure variation of temperature amount a0 when turntable rotates a circle.
In step S202, utilize the value of look-up table according to the variable quantity a0 calculating K d that in step S201, calculates.After calculating the value of Kd, just measure the Current Temperatures T (k) of food whenever a magnetron connection/cut-out cycle of past (tm).After this, the value that---it deducts initial temperature T (0) with Current Temperatures T (k) and obtains---multiply by Kd with temperature value in step S203 is calculated magnetron ratio turn-on time P.(it deducts the value that value that variable quantity by T (the k)-T (k-1) of the load temperature of measuring in each multiply by Kd obtains by the magnetron ratio turn-on time P that obtains in magnetron connection/cut-out cycle (tm) and obtains in step S203) on duty when being less than or equal to constant Dr, stops thawing operation.In other situation, repeat this operation by increasing a magnetron connection/cut-out cycle.
So far determined the variation of temperature amount A0 that in the process that turntable rotates a circle, measures and depended on thawing of load offset to finish regularly, so that so thaw frozen food.
As mentioned above, the method of defreezing by microwave oven of a thermocouple sensor that utilizes according to the present invention utilizes the measurement temperature of thermocouple sensor to control the output of magnetron (therefore having shortened thawing time), with utilize this thermocouple sensor to calculate the rotate a circle measurement variation of temperature amount of time of turntable, thereby the frozen food that can under optimum condition, thaw, and needn't consider the size of food.In addition, by determining to depend on thawing the deadline of load offset, can carry out the best operation of thawing, and needn't consider the position of load (food).
Although described the preferred embodiments of the present invention for illustrative purposes, those of ordinary skill in the art will understand and can carry out various modifications to it, increase and replace, and the scope and spirit of the present invention that do not break away from claims to be quoted from.
Claims (9)
1. a micro-wave oven that has a thermocouple comprises: a ultrared light collecting device that is used to assemble from food, one is used to produce corresponding to from the infrared ray of light collecting device with from the transducer module (thermocouple sensor) of the ultrared voltage of turntable, one is used for the amplifier that is amplified to a predetermined level from the output voltage of transducer module, one is used for the A/D converter that is converted to digital voltage signal from the voltage signal of amplifier, with a voltage signal that is used to handle from A/D converter, the algorithm control magnetron connection/cut-out switch of the thaw routine that provides according to a relevant inside, supply with the microcomputer of the energy be placed on the food the heating clamber with control from magnetron, described microcomputer comprises:
One is used for reading voltage signal sampling unit from the data signal of A/D converter at each time ts;
One is used for the voltage signal that extracts at each voltage time is converted to temperature T, elimination is from the noise of the temperature T of conversion, with the maximum of T max that calculates (tm) time in magnetron connection/cut-out cycle, the voltage signal processing unit of minimum of a value Tmin and mean value Tmean;
One is used for the maximum of T max in the relevant temperature T in a magnetron connection/cut-out cycle, the temperature data sampling unit of minimum of a value Tmin and mean value Tmean sampling;
One is used to utilize the optimal magnetron connection/break time of the data computation of temperature data sampling unit sampling a magnetron connection/cut-out cycle, determine to make thaw magnetron ratio turn-on time of operation of deadline and stopping when judging that the food state is determined to have abnormal operation of thawing of operating in that Best Times stops that thaws to calculate and the abnormal operation judging unit; With
One is used for exporting a signal and controlling a magnetron connection/cut-out on-off controller from the output of magnetron to magnetron connection/cut-out switch according to the output from calculating of magnetron ratio turn-on time and abnormal operation judging unit.
2. micro-wave oven as claimed in claim 1, wherein said voltage signal processing unit is utilized an algorithm that is used to change at the voltage signal of each time ts sampling, a digital filter algorithm that is used to eliminate from the noise of temperature T, the maximum value calculation algorithm of the maximum of T max of a temperature that is used to calculate (tm) time in magnetron connection/cut-out cycle, the minimum of a value computational algorithm of the minimum of a value Tmin of a temperature that is used to calculate (tm) time in magnetron connection/cut-out cycle and one are used to calculate the mean value calculation algorithm process signal of mean value Tmean of the temperature of (tm) time in magnetron connection/cut-out cycle.
3. defreezing method that utilizes the micro-wave oven of a thermocouple sensor comprises step:
One is cut off a period of time to magnetron---time that turntable rotates a circle when being used in input during this period of time and thawing key signals adds that the rotation response time before the turntable motor normal rotation obtains---and detect the first step of the initial temperature of food;
Maximum of T max who utilizes digital filter that the temperature T that detects in first step is filtered into Tf and calculate the magnetron connections/cut-out cycle about the temperature T f of filtration, second step of a minimum of a value Tmin and a mean value Tmean;
Judge whether a magnetron connection/cut-out cycle go over for one, when judged result is the third step that does not have past tense to turn back to first and second steps in the magnetron connection/cut-out cycle and utilize a filtration value Tmaxf of maximum of T max calculating who filters when the magnetron connection/cut-out cycle is over and done with;
The changing value Δ Tmaxf of the filtration value Tmaxf of the maximum of T max of calculating in third step and judge the 4th step of the recruitment of this value;
One is calculated an additional thawing time when changing value Δ Tmaxf increases in the 4th step, determine the deadline of thawing, and calculates magnetron ratio turn-on time and the 5th step of calculating magnetron ratio turn-on time when changing value does not increase;
One is utilized magnetron ratio turn-on time and mean value Tmean, and the current time that passes is judged the 6th step of the abnormality of the mode of operation of the algorithm that thaws and food; With
The 7th step of when decision operation is abnormality in the 6th step, thaws and operating and when decision operation is not abnormality, turn back to first step by the termination of cut-out magnetron.
4. method as claimed in claim 3, wherein said magnetron ratio turn-on time P utilizes the minimum of a value Tmin of the associated temperature of food to calculate, rather than with the temperature T of food.
5. method as claimed in claim 3, the wherein said deadline of thawing is to utilize the maximum of T max of the associated temperature of food to calculate, rather than with the temperature T of food.
6. method as claimed in claim 3, wherein said abnormality be utilize relevant temperature T one average time Tmean, magnetron ratio turn-on time P and current time that passes are judged.
7. method as claimed in claim 3, wherein in the 4th step, pass the time during current less than three magnetron connection/cut-out cycles (3*tm), the value of Δ Tmaxf (tr) (it is the value of Δ Tmaxf) is compared with the value (it is the value at the Δ Tmaxf of tm before the time) of Δ Tmaxf (tr-tm), when the value of Δ Tmaxf (tr) during greater than the value of Δ Tmaxf (tr-tm), the changing value Δ Tmaxf that judges the filtration value Tmaxf of maximum of T max increases, when the value of Δ Tmaxf (tr) is not more than the value of Δ Tmaxf (tr-tm), judge that it is not increasing.
8. method as claimed in claim 3, wherein in the 4th step, current when passing time tr greater than three magnetron connection/cut-out cycles (3*tm), the value of Δ Tmaxf (tr) (it is the currency of Δ Tmaxf) is compared with the value (they are the values of the Δ Tmaxf before the time at tm and 2*tm) of Δ Tmaxf (tr-tm) and Δ Tmaxf (tr-2*tm), when the value of Δ Tmaxf (tr) value greater than Δ Tmaxf (tr-tm), greater than the value of Δ Tmaxf (tr-2*tm)+δ (less than 0 positive number) time, judge that the changing value Δ Tmaxf of the filtration value Tmaxf of maximum of T max increases with the value of Δ Tmaxf (tr).
9. defreezing method that utilizes the micro-wave oven of a thermocouple sensor comprises step:
The rotate a circle first step of measurement variation of temperature amount of time of calculating turntable;
One is calculated second step that depends on the value Kd that changes corresponding to the offset of the variable quantity that calculates in first step;
One by multiply by the third step that different weighted values is calculated magnetron ratio turn-on time P to a temperature value (it be Current Temperatures by the load in each magnetron connection/cut-out cycle (tm) deduct initial temperature obtain); With
One when Kd on duty obtained this value with a load temperature variable quantity of measuring in each in magnetron connection/cut-out cycle (tm), stop the 4th step of thawing and operating.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR20800/1996 | 1996-06-11 | ||
| KR1019960020800A KR100186390B1 (en) | 1996-06-11 | 1996-06-11 | Method of defrosting frozen food in a microwave oven |
| KR20800/96 | 1996-06-11 | ||
| US08/871,405 US6013907A (en) | 1997-06-09 | 1997-06-09 | Microwave oven equipped with thermopile sensor and thawing method using the same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1172229A true CN1172229A (en) | 1998-02-04 |
| CN1106537C CN1106537C (en) | 2003-04-23 |
Family
ID=26631899
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN97112111A Expired - Fee Related CN1106537C (en) | 1996-06-11 | 1997-06-11 | Microwave oven equipped with thermopile sensor and thawing method using the same |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JP3270714B2 (en) |
| KR (1) | KR100186390B1 (en) |
| CN (1) | CN1106537C (en) |
| BR (1) | BR9703528B1 (en) |
| GB (1) | GB2314173B (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100434806C (en) * | 2004-07-20 | 2008-11-19 | 石芹侠 | Contact type temperature measuring and controlling instrument for microwave oven |
| CN102235693A (en) * | 2010-04-27 | 2011-11-09 | 乐金电子(天津)电器有限公司 | Defrosting method of microwave oven |
| CN106403482A (en) * | 2016-08-29 | 2017-02-15 | 合肥华凌股份有限公司 | Unfreezing device, unfreezing method and refrigerator |
| CN106455863A (en) * | 2014-06-06 | 2017-02-22 | 皇家飞利浦有限公司 | Cooking device and method of cooking food item based on predicting food core temperature |
| CN110916533A (en) * | 2019-11-27 | 2020-03-27 | 上海达显智能科技有限公司 | Baking control method and device for baking equipment, baking equipment and toaster |
| CN111713959A (en) * | 2019-03-22 | 2020-09-29 | 夏普株式会社 | Heating device |
| CN112013432A (en) * | 2020-07-17 | 2020-12-01 | 广东美的厨房电器制造有限公司 | Microwave oven, control method thereof, and computer readable medium |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2337832B (en) * | 1998-05-29 | 2002-07-31 | Sanyo Electric Co | Cooking appliance that can detect temperature of foodstuff using infrared sensor |
| JP3762580B2 (en) * | 1999-08-12 | 2006-04-05 | 株式会社東芝 | Cooker |
| FR2810493B1 (en) * | 2000-06-20 | 2004-09-24 | Brandt Cooking | METHOD AND APPARATUS FOR HEATING A FOOD AT A SETPOINT TEMPERATURE |
| SE523597C2 (en) * | 2000-11-23 | 2004-05-04 | Skarhamn Internat Ab | Method and apparatus for thawing frozen goods consisting of an organic cell mass such as food |
| KR100518445B1 (en) * | 2003-07-18 | 2005-09-29 | 엘지전자 주식회사 | Apparatus for controlling of micro wave oven and method thereof |
| JP4967796B2 (en) * | 2007-05-15 | 2012-07-04 | パナソニック株式会社 | Microwave heating device |
| MD391Z (en) * | 2009-08-04 | 2012-01-31 | Институт Химии Академии Наук Молдовы | Device for measuring the temperature in a microwave oven |
| JP6641560B2 (en) * | 2016-09-30 | 2020-02-05 | 東芝ホームテクノ株式会社 | Cooker |
| JP6681595B2 (en) * | 2017-02-24 | 2020-04-15 | パナソニックＩｐマネジメント株式会社 | Heating cooker and reheating method in heating cooker |
| JP7207777B1 (en) * | 2021-09-24 | 2023-01-18 | シロカ株式会社 | heating cooker |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5597612A (en) * | 1979-01-20 | 1980-07-25 | Sanyo Electric Co Ltd | Electronic control type cooking unit |
-
1996
- 1996-06-11 KR KR1019960020800A patent/KR100186390B1/en not_active IP Right Cessation
-
1997
- 1997-06-10 GB GB9712055A patent/GB2314173B/en not_active Expired - Fee Related
- 1997-06-11 JP JP15347597A patent/JP3270714B2/en not_active Expired - Fee Related
- 1997-06-11 CN CN97112111A patent/CN1106537C/en not_active Expired - Fee Related
- 1997-06-11 BR BRPI9703528-9A patent/BR9703528B1/en not_active IP Right Cessation
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100434806C (en) * | 2004-07-20 | 2008-11-19 | 石芹侠 | Contact type temperature measuring and controlling instrument for microwave oven |
| CN102235693A (en) * | 2010-04-27 | 2011-11-09 | 乐金电子(天津)电器有限公司 | Defrosting method of microwave oven |
| CN102235693B (en) * | 2010-04-27 | 2015-06-10 | 乐金电子(天津)电器有限公司 | Defrosting method of microwave oven |
| CN106455863A (en) * | 2014-06-06 | 2017-02-22 | 皇家飞利浦有限公司 | Cooking device and method of cooking food item based on predicting food core temperature |
| CN106403482A (en) * | 2016-08-29 | 2017-02-15 | 合肥华凌股份有限公司 | Unfreezing device, unfreezing method and refrigerator |
| CN111713959A (en) * | 2019-03-22 | 2020-09-29 | 夏普株式会社 | Heating device |
| CN110916533A (en) * | 2019-11-27 | 2020-03-27 | 上海达显智能科技有限公司 | Baking control method and device for baking equipment, baking equipment and toaster |
| CN110916533B (en) * | 2019-11-27 | 2021-05-25 | 上海达显智能科技有限公司 | Baking control method and device for baking equipment, baking equipment and toaster |
| CN112013432A (en) * | 2020-07-17 | 2020-12-01 | 广东美的厨房电器制造有限公司 | Microwave oven, control method thereof, and computer readable medium |
Also Published As
| Publication number | Publication date |
|---|---|
| KR100186390B1 (en) | 1999-03-20 |
| GB9712055D0 (en) | 1997-08-13 |
| JPH1096517A (en) | 1998-04-14 |
| CN1106537C (en) | 2003-04-23 |
| BR9703528A (en) | 1998-10-06 |
| BR9703528B1 (en) | 2009-08-11 |
| GB2314173A (en) | 1997-12-17 |
| KR980003213A (en) | 1998-03-30 |
| JP3270714B2 (en) | 2002-04-02 |
| GB2314173B (en) | 1999-06-16 |
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