KR0176919B1 - Food temp.control method and device thereof in ref. - Google Patents

Abstract

The present invention relates to a food temperature sensing apparatus and method of a refrigerator, and in the related art, when the viewing angle is wider than the size of the load, the load temperature detection is affected by the infrared rays emitted by other objects in the viewing angle in addition to the infrared radiation emitted by the load. Difficult, the narrow angle of view enables accurate load temperature detection, but requires a separate drive device difficult to configure the device, the reliability is reduced due to the limitation of the life of the drive device.

In addition, since the technology applied to the refrigerator is not conventional, there is a problem in that the reliability of the driving device for driving the thermopile sensor is degraded when the application time is long.

Therefore, the present invention accurately detects the food temperature introduced into the refrigerator by using a thermopile sensor and thermistor so that the food can be stored at a temperature maximizing the freshness of the food so that the food storage in the refrigerator has a great effect in improving storage. do.

Description

Food temperature sensing device and method of refrigerator

1 is a configuration diagram of a load temperature sensor using a thermopile sensor of a conventional microwave oven.

2 is a view showing a viewing angle of a driving device and a thermopile sensor for driving a conventional thermopile sensor.

3 is a block diagram of a food temperature sensing apparatus of the present invention refrigerator.

4 is a detailed configuration of the food temperature sensing apparatus of the present invention a refrigerator.

FIG. 5 is a detailed structural diagram of the food position / size sensing means in FIG.

(a) is the formation structure of thermistor,

(b) is a structural diagram showing the shape of the first food support,

(c) is a structural diagram of the first food support,

(d) is a structural diagram of the second food support part.

FIG. 6 is a diagram for explaining the relationship between the viewing angle of the thermopile sensor and the food distance in FIG.

7 is a flowchart illustrating a food temperature sensing method of the refrigerator of the present invention.

FIG. 8 is an explanatory diagram showing the case where the size of food is larger than the viewing angle of the thermopile sensor in FIG.

FIG. 9 is an explanatory diagram showing a case where the size of food is smaller than the viewing angle of the thermopile sensor in FIG.

10 is another flow chart of the food temperature sensing method of the present invention refrigerator.

* Explanation of symbols for main parts of the drawings

10: Thermopile sensor 20: Food position / size detection unit

20a: thermistor 20b: lead wire

20c: hole 20d: first food support

20e: protrusion 20f: second food support

30: temperature sensing unit 40: temperature compensating unit

The present invention relates to the detection of food temperature in a refrigerator. In particular, the temperature of the food put into the refrigerator is accurately sensed using a thermopile sensor and a plurality of thermistors, so that the food can be stored at a temperature that maximizes the freshness of the food. It relates to a food temperature sensing device and method.

The load temperature sensing device configuration using the thermopile sensor of the conventional microwave oven, as shown in Figure 1, by detecting the infrared radiation emitted from the load (1) with a guide to the heating chamber and converts the detected infrared rays into a voltage value From the thermopile sensor 2 to be output, the analog / digital converter 3 for converting the analog voltage value output from the thermopile sensor 2 into a digital value, and from the analog / digital converter 3 The load temperature detection unit 4 receives the value received and measures the load temperature, and recognizes the progress of cooking according to the load temperature received from the load temperature detection unit 4, and the appropriate temperature desired by the load temperature is determined. Is it possible to output the control signal of the microcomputer 5 for controlling each necessary part and the microcomputer 5 for cooking the food at an appropriate level according to the detected load temperature? The heat control part 6 and the heating part 7 which heat a load using a magnetton, a heater, etc. according to the control output of the said heating control part 6 are comprised.

Looking at the conventional technology configured as described above are as follows.

When the user places the load 1 on the turntable 8 located in the center of the heating chamber and selects a cooking start key through a key matrix not shown, the microcomputer 5 recognizes this and controls to perform cooking. The signal is output to the heating unit 7 through the heating control unit 6.

When cooking starts, the turntable 8 starts to rotate, and the load 1 placed on the turntable 8 also starts to rotate together, and electromagnetic waves or heat are generated by the heating unit 7 made of a magnettone or a heater. Then, when cooking proceeds, infrared rays are emitted from the load 1 and the infrared rays are detected by the thermopile sensor 2 and converted into voltages corresponding to the detected infrared rays to convert the analog / digital converter 3. )

Accordingly, when the analog / digital converter 3 converts the analog voltage value into a digital value and transmits the analog voltage value to the load temperature detector 4, the load temperature detector 4 detects the load temperature from the input digital value. And output to the microcomputer 5.

Therefore, the microcomputer 5 receives the load temperature output from the load temperature sensor 4 to recognize the progress of cooking, and transmits a control signal to the heating unit 7 through the heating control unit 6 so that proper cooking proceeds. ) To finish cooking.

However, in FIG. 1, only a temperature of a load placed in a fixed viewing angle using a thermopile sensor was measured.

Therefore, when the load is out of the viewing angle, as shown in FIG. 2, the driving device for driving the thermopile sensor is narrowed, and the viewing angle of the thermopile sensor is narrowed. After sensing, the temperature of the load was obtained.

However, in the prior art as described above, when the viewing angle is wider than the size of the load, it is difficult to accurately detect the load temperature due to the influence of the infrared rays emitted by other objects in the viewing angle in addition to the infrared rays emitted by the load. Accurate load temperature can be detected, but a separate drive device is required, which makes the device difficult to configure and reduces reliability due to limitations due to the life of the drive device.

In addition, since the technology applied to the refrigerator has not been conventionally applied to the refrigerator, there is a problem in that the reliability of the driving device for driving the thermopile sensor is degraded because the use time is long.

Accordingly, an object of the present invention is to provide a food temperature sensing apparatus and method of a refrigerator to accurately detect the temperature of the food put into the refrigerator, to store the food at a temperature that maximizes the freshness of the food, thereby contributing to the improvement of food storage. In providing.

Food temperature sensing method of the refrigerator according to the present invention for achieving the above object, as shown in Figure 7, the first step of detecting the temperature in the refrigerator using a plurality of thermistors for a predetermined period; A second step of measuring a change in the average temperature by calculating an average value for the change in the temperature sensed in the first step; A third step of determining the actual food size by comparing the average value calculated in the second step and the set value to obtain the number of thermistors larger than the set value; A fourth step of inferring a compensation value of the food temperature using the number of thermistors obtained in the third step; A fifth step of obtaining an actual food temperature value by compensating the food temperature directly sensed by the thermopile sensor with the compensation value inferred in the fourth step; The sixth step is to detect the on / off of the refrigerator door to recognize that the new food came on at the time of sensing the temperature of the food again and to continuously correct the temperature in the food when off.

As shown in FIG. 3, the food temperature sensing device of the refrigerator according to the present invention for carrying out the method comprising the steps described above detects infrared rays emitted from the food stored in the refrigerator, and detects the infrared rays as voltage values. A thermopile sensor for converting the output to a sensor; Food position / size sensing means for determining the position and size of the food and for sensing the temperature around the food; Temperature sensing means for sensing the temperature of the food by inputting the voltage value transmitted from the thermopile sensor and inferring a compensation value of the food temperature using the food size input from the food position / size sensing means; And a temperature compensating means for obtaining an actual food temperature value compensated by using the temperature of the food output from the temperature sensing means and the compensation value.

In the above, the food position / size detection means, a plurality of thermistors to measure the temperature of the vicinity of the food; A first food support portion to which conductive wires connected to the plurality of thermistors are printed and into which the thermistors are inserted; The second food support is provided with a plurality of protrusions forming a space so that the thermistor is seated on the plane.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

4 is a configuration diagram of a food temperature sensor of a refrigerator according to the present invention. As shown in the drawing, a thermopile sensor which detects infrared rays emitted from food stored in a refrigerator, converts the detected infrared rays into voltage values, and outputs them. 10); A food position / size sensing unit 20 for determining the position and size of the food and sensing the temperature around the food; The temperature sensing unit detects the temperature of the food by inputting the voltage value transmitted from the thermopile sensor 10 and infers a compensation value of the food temperature using the food size input from the food position / size sensing unit 20. 30; The temperature compensation unit 40 is configured to obtain the actual food temperature value compensated using the temperature and the compensation value of the food output from the temperature sensing unit 30.

And, the food position / size detection unit 20, as shown in Figure 5, a plurality of thermistors (20a) formed of a matrix to measure the temperature of the vicinity of the food; A first food support 20d to which conductive wires 20b connected to the plurality of thermistors 20a are printed, and into which the thermistors 20a are inserted; The second food support portion 20f is provided with a plurality of protrusions 20e forming a space so that the thermistor 20a is seated on a plane.

Referring to the operation and effect of the present invention configured as described in detail as follows.

When the consumer opens the refrigerator door and puts food in the refrigerator, the thermopile sensor 10 detects infrared rays emitted by the food present in its viewing angle to determine temperature information of the portion.

At this time, if the size of the food is larger than the viewing angle as shown in FIG. 8, the temperature measured by the thermopile sensor 10 is close to the temperature of the food, but as shown in FIG. 9, the food is viewed from the thermopile sensor 10. If occupies only a part of the temperature, the temperature measured by the thermopile sensor 10 due to the infrared rays emitted by the object in the portion of the field not occupied by the food is different from the temperature of the food.

In order to compensate for this measurement error, when the food occupies only a part of the viewing angle, the second food support portion of the food position / size sensing unit 20 on which the food is placed is removed in order to eliminate the effect of infrared radiation of the remaining part. Made of material with very low emissivity.

Here, looking at the configuration of the food position / size detection unit 20, as shown in Figure 5 (a) a plurality of thermistors (20a) for sensing the temperature of the surrounding food is formed in a matrix form, Conductors 20b are connected to the four thermistors 20a, and the conductors 20b are formed of holes 20c at positions where the plurality of thermistors 20a are seated, as shown in FIG. 5 (b). 1 It is printed on the food support 20d as shown in FIG. 5 (c).

The first food support 20d is made of an insulator so that the conductive wires 20b are not electrically shorted with each other, and the second food support 20e, which is bonded on the first food support 20d and directly comes into contact with food, is made of As shown in FIG. 5 (d), the projections 20e are provided so that the thermistors are seated at the plurality of thermistors 20a, and the emissivity of infrared rays is made of extremely low material.

And, as shown in FIG. 6, the thermopile sensor 10 has a fixed viewing angle [theta] and receives infrared radiation of food belonging to a circle of radius r when the distance between the sensor and the food is h. It is designed to detect food temperature.

Therefore, when the food occupies only a part of the viewing angle of the thermopile sensor 10, the food occupies the ratio of the viewing angle, and the temperature measured by the thermopile sensor 10 is compensated by the above ratio to obtain an accurate food temperature.

That is, when the viewing angle is R, the area occupied by the food is r, and the temperature measured by the thermopile sensor 10 is T _p , the temperature T of the food is expressed by Equation 1 below.

In Equation (1), R is a value that can be known when the viewing angle of the thermopile sensor 10 is fixed, so that the exact food temperature can be known from Eq.

In order to compensate the temperature of the food put into the refrigerator, first, when the food is placed on the second food support 20f of the food position / size sensing unit 20, the conductive wire 20b connected to the thermistors 20a of the placed portion is placed. Through the temperature information is transferred to the temperature sensing unit 30 as shown in Equation (2) below.

Then, the thermistor 20a of the food position / size detector 20 detects the temperature in the vicinity of the food, and the number of detection is continuously measured by the set repetition number K _s to the temperature detector 30. To pass.

The temperature sensing unit 30 calculates the amount of change in the temperature value measured and transmitted each time as shown in Equation (2) below.

After calculating the amount of change in temperature detected by the set number of repetitions (K _s ) as in Equation (2), the average value for the amount of change is calculated as in Equation (3) below.

The average value obtained from Equation (3) is compared with the set value (T _s ) as shown in Equation (4) below to obtain the number of thermistors having a higher temperature change rate than the set value (Ts) and the thermistors that are not. As described above, the compensation value C of the food temperature can be known by the ratio of the food size r to the viewing angle area R.

In the same way as described above, the temperature compensator 40 detects the temperature (T _p ) with the thermopile sensor 10 after obtaining the compensation value C of the food temperature, and expresses this value as shown in Equation (6). To compensate, recognize the actual food temperature value (T).

The compensation value (C) thus obtained is used until new food is introduced, and when the new food is detected by the same method as the door open detection, the compensation value (C) is again obtained. Sense the temperature.

Referring to the above operation process again based on the flowchart shown in FIG. 7, the temperature detection frequency (k) of the thermistor is set to zero " 0 " (k = 0) when food is put into the refrigerator. temperature information through a lead wire connected to the thermistor (T _i (k)) changes the value of the detected temperature by receiving a (△ T _i (k)) that is, in a sense to that before the n-th one thermistor detects temperature temperature Calculate the difference.

As described above, the temperature information _Ti (k) and the change value ΔT _i (k) of the temperature are calculated by the set number k _s .

After the calculation is completed for the set number of times k _s , the average value Avg (ΔT _i ) of the change values of the temperature calculated so far is calculated.

Compute the calculated average temperature change Avg (ΔT _i ) with the set value T _s , and if the average temperature change Avg (ΔT _i ) is larger than the set value T _s , obtain the number of thermistors at this time. Using this number of thermistors, we find the actual food size.

Therefore, the compensation value C of the food temperature is inferred by using the number of thermistors whose temperature change average value Avg (ΔT _i ) is larger than the set value T _s .

That is, the compensation value (C) of food temperature is the number of thermistors (i ') whose temperature change average value (Avg (ΔT _i )) is larger than the set value (T _s ) divided by the total number of thermistors (i). do.

When the compensation value (C) of the food temperature are determined as above by thermopile sensor temperature of the food (T _p) directly detected and the temperature of the detected food products to (T _p) a temperature compensation value (C) Multiply by to know the actual food temperature value (T = T _p * C).

In this way, when the temperature of the food is corrected by detecting the on / off of the door of the refrigerator, when it is on, new food is recognized and the temperature of the food is detected again, and when it is off, the temperature of the food is continuously corrected. do.

In addition, when the food location / size detection unit 20 does not make the second food support part with an extremely low infrared emissivity material such as aluminum, when the food occupies only a part of the viewing angle, it compensates for the effect of infrared radiation of the remaining part. The method to give is as follows.

Since the temperature measured by the thermopile sensor 10 is a value obtained by averaging the temperature of the food and the temperature of the second food support portion in which the food in the viewing angle is not placed, the temperature measured by the thermopile sensor 10 is T _p , and the viewing angle is measured. When the area occupied by the food is r, the viewing angle is R, and the temperature of the second food support portion in which the food is not placed is T _k , the food temperature is represented by Equation (7).

In Equation (7), K _T is a constant relating to infrared emissivity with temperature at the second food support.

The area r occupied by the food in the viewing angle in Equation (7) is obtained as follows.

When the food is put into the interior, the temperature information is transferred to the temperature sensing unit 30 as shown in Equation (8) through the wires connected to the thermistors in the food position / size sensing unit 20 by the set number of repetitions (K _s ). The measurement was continued, and the measured temperature information was the same as in the above formula (2).

The temperature sensor 30 receiving the temperature information calculates a change amount of temperature each time and then averages the change amounts so far as shown in Equation (3).

When the number of thermistors having a higher temperature change rate than the set value and the number of thermistors having a higher temperature change rate than the set value are obtained by comparing the averaged value with the set value (K _s ), the food size (r) for the viewing angle area (R) ) Ratio can be known, and the compensation value (C) is obtained according to equation (5).

After obtaining the compensation value (C) of the food temperature as described above, the temperature sensor 30 senses the temperature (T _p ) with the thermopile sensor 10, and the temperature (the temperature of the second food support portion where the food is not placed by the thermistor ( T _k ) is sensed and provided to the temperature compensator 40.

Accordingly, the temperature compensator 40 receives the compensation value C and the temperature T _k of the second food support portion in which the food is not placed, and compensates this temperature value as shown in Equation (8) to actual food temperature value T. Recognize.

Here, K _T is a constant relating to the infrared emissivity according to the temperature of the second food support.

The compensation value (C) thus obtained is used until new food is introduced, and when the new food is detected by the same method as the door open detection, the compensation value (C) is again obtained. Sense the temperature.

When the second food support portion, which is the place where food is placed, is not made of a material having extremely low infrared emissivity, once again referring to the flow chart of FIG. 10, first, the temperature detection frequency (k) of the thermistor is zero " 0 " If (k = 0) the food is put into the refrigerator, the temperature information (T _i (k)) of the part where the food is placed is input through the lead wires connected to the thermistors. The amount of change ΔT _i (k) is calculated.

At this time, the change amount of temperature ΔT _i (k) is calculated by the set number of times k _s .

After the calculation is completed for the set number of times k _s , the average value Avg (ΔT _i ) of the change values of the temperature calculated so far is calculated.

Compute the calculated average temperature change Avg (ΔT _i ) with the set value T _s , and if the average temperature change Avg (ΔT _i ) is larger than the set value T _s , obtain the number of thermistors at this time. Using this number of thermistors, we can infer the compensation value (C) of food temperature.

That is, the compensation value (C) of food temperature is the number of thermistors (i ') whose temperature change average value (Avg (ΔT _i )) is larger than the set value (T _s ) divided by the total number of thermistors (i). do.

When the compensation value (C) of the food temperature is obtained as described above, the thermopile sensor directly detects the temperature (T _p ) of the food, and detects the temperature (T _k ) of the second food support portion in which the food is not placed by the thermistor. This value is multiplied as follows to recognize the actual food temperature value (T).

In this way, when the temperature of the food is corrected by detecting the on / off of the door of the refrigerator, when it is on, new food is recognized and the temperature of the food is detected again, and when it is off, the temperature of the food is continuously corrected. do.

As described in detail above, the present invention accurately detects the food temperature introduced into the refrigerator by using a thermopile sensor and thermistor so that the food can be stored at a temperature maximizing the freshness of the food, thereby improving storage characteristics when storing the food in the refrigerator. Make it a big effect.

Claims (10)

A thermopile sensor which detects infrared rays emitted from the food stored in the refrigerator and converts the detected infrared rays into voltage values; Food position / size sensing means for determining the position and size of the food and for sensing the temperature around the food; Temperature sensing means for sensing the temperature of the food by inputting the voltage value transmitted from the thermopile sensor and inferring a compensation value of the food temperature using the food size input from the food position / size sensing means; And a temperature compensating means for obtaining an actual food temperature value compensated by using the temperature and the compensation value of the food output from the temperature sensing means. 2. The apparatus of claim 1, wherein the food position / size sensing means comprises: a plurality of thermistors for measuring the temperature in the vicinity of the food; A first food support portion to which conductive wires connected to the plurality of thermistors are printed and into which the thermistors are inserted; Food temperature sensing device of the refrigerator, characterized in that consisting of a second food support provided with a plurality of projections to form a space so that the thermistor is seated on the plane. The food temperature sensing apparatus of the refrigerator of claim 1 or 2, wherein the thermistor is formed in a matrix form. The food temperature sensing apparatus of the refrigerator of claim 2, wherein the first food support part is made of an insulator so that the conductors are not electrically shorted. The food temperature sensing apparatus of the refrigerator according to claim 2, wherein the second food support part is made of a material such as aluminum having extremely low infrared emissivity and excellent thermal conductivity. A first step of sensing a temperature in a refrigerator by using a plurality of thermistors for a predetermined period; A second step of measuring a change in the average temperature by calculating an average value for the change in the temperature sensed in the first step; A third step of determining the actual food size by comparing the average value calculated in the second step and the set value to obtain the number of thermistors larger than the set value; A fourth step of inferring a compensation value of the food temperature using the number of thermistors obtained in the third step; A fifth step of obtaining an actual food temperature value T by compensating the food temperature T _p directly sensed by the thermopile sensor with the compensation value C inferred in the fourth step; The food temperature sensing method of the refrigerator comprising the sixth step of detecting the on / off of the refrigerator door to recognize that the new food came on at the same time to detect the temperature of the food again and to continuously correct the temperature in the food when off . 7. The method of claim 6, wherein the compensation value of the food temperature is calculated by dividing the total number of thermistors by the number of thermistors having a larger average value of temperature change than the set value. The method according to claim 6, wherein in step 5, the actual food temperature value T is obtained by multiplying the temperature T _p sensed by the thermopile sensor by the compensation value C (T = T _p * C). Food temperature sensing method of the refrigerator characterized in that. A first step of sensing the temperature of the vicinity of the food using a plurality of thermistors for a certain period of time; A second step of measuring a change in the average temperature by calculating an average value for the change in the temperature sensed in the first step; A third step of determining the actual food size by comparing the average value calculated in the second step and the set value to obtain the number of thermistors larger than the set value; A fourth step of inferring a compensation value of the food temperature using the number of thermistors obtained in the third step; A fifth step of directly sensing the food temperature T _p by a temperature T _k and a thermopile sensor on which the food support is not placed with the thermistor; A sixth step of obtaining an actual food temperature value (T) using the compensation value (C) deduced in the fourth step and the temperature (T _k ) (T _p ) detected in the fifth step; The food temperature sensing method of the refrigerator comprising a seventh step of detecting the on / off of the refrigerator door to recognize that the new food came on at the same time to detect the temperature of the food again and to continuously correct the temperature in the food when off . 10. The method of claim 9, wherein the actual food temperature value T in the sixth step is obtained by the method as follows. However, K _T is a constant for the infrared emissivity according to the temperature of the food support