JPH06137739A - Defreezing control device - Google Patents

Abstract

PURPOSE:To perform a defreezing controlling operation for defreezing frozen foods in response to a weight and a size of the foods. CONSTITUTION:At a first fuzzy inference processor 60, a fuzzy logic calculation is carried out in response to a first stage time, a second stage time and a control rule taken out of a first memory 61 by a time memory means 58 for storing a first stage time where an electrical energization of a radiation heater 31 is increased up to a predetermined temperature by a defreezing chamber temperature sensor and by a time memory means 59 for storing a temperature of the defreezing chamber temperature sensor upon completion of a second stage and then a rate off electrical energization at a third stage is calculated and then the radiation heater 31 at the third stage is controlled in response to this result of calculation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerator with a thawing chamber for thawing frozen food.

[0002]

2. Description of the Related Art Conventionally, an example of using a heater for thawing frozen food is known. For example, Japanese Patent Publication Sho 48
This is the example shown in Japanese Patent Publication No. 25414, and FIG.
It will be described with reference to FIG. Reference numeral 1 denotes a thawing box, which includes an outer box 2 made of metal or synthetic resin, and an inner box 3 made of aluminum or the like having a large thermal conductivity and provided inside the outer box 2 with an appropriate interval. Has been formed. Reference numeral 4 denotes a linear heater, which is heat conductively adhered to the inner box 3 by an aluminum foil 5 such that the bottom surface of the thawing box 1 is sparse and the top surface is dense. 6 is the outer box 2 and aluminum foil 5
It is a heat insulating material interposed between.

In such a structure, when the food to be thawed 7 is placed on the bottom of the thaw box and the thaw action is started, the heater 4 is heated.
The heat is applied from the entire circumference of the inner box 3 to heat the food 7 to be thawed to cause the food to be thawed.

[0004]

However, in such a configuration, although heat can be transferred from the bottom portion of the thawing box to the bottom portion of the food to be thawed by heat conduction, the bottom portion can be thawed, but the top surface of the thawing box can be thawed. And there is little radiant heating from the sides, and heating is primarily by convection of warmed air in the thaw box. Therefore, there is a problem that the thawing unevenness with the central portion of the food to be thawed is likely to be large, the thawing time is long, and the thawing quality depends on the weight and size of the food. There is also a problem that the finished state is not constant depending on the weight and size of the food.

The present invention solves the above-mentioned problems, and an object of the present invention is to reduce unevenness in thawing and to perform thawing in a short time and with peace of mind.

[0006]

In order to solve the above-mentioned problems, a refrigerator according to the present invention has a radiation heater covered with a curved reflecting plate.
In contrast to the configuration in which the cool air whose flow rate is adjusted by the fan and the damper device is introduced into the defrosting chamber which has the temperature sensor on the upper surface and the temperature sensor on the back surface of the bottom plate that is heat conductively adhered to the lower surface, As a step, a first timer for measuring the time from the start of thawing until the temperature sensor rises to a predetermined temperature, a time storage means for storing the time measured by the first timer, and a first step of energizing the radiant heater A first duty ratio setting means for setting the rate, a second timer for setting the time of the second stage,
A temperature storage means for storing the temperature of the temperature sensor at the end of the second stage, and a second for setting the energization rate of the second stage of the radiant heater.
And a memory for storing a control rule based on an empirical rule for obtaining the duty ratio of the radiant heater in the third stage, and a time and temperature storage unit in the first stage stored in the time storage unit. Based on the temperature at the end of the second stage and the control rule fetched from the memory, the fuzzy inference processor for performing the fuzzy logic operation to calculate the duty ratio of the radiant heater in the third step, and the fuzzy inference processor And a third timer for setting the time of the third step, and a third, third, and third duty ratio setting means for setting the duty ratio of the third-stage radiant heater. The radiant heater control means for controlling the radiant heater based on the signal and the control means for forcibly operating the fan and forcibly releasing the damper device in the first stage and forcibly closing the damper device in the second stage are provided.

Further, in order to determine the finished state of thawing, for example, hardened or softened according to the preference of the user, a finish setting switch for inputting the preference of the user and the energization rate of the radiant heater. It is provided with a plurality of memories for storing control rules based on empirical rules and finish selecting means for judging which one of the plurality of memories should be selected according to the state of the finish setting switch.

A fan and a damper unit flow into a thawing chamber having a radiation sensor covered with a curved reflector on the upper surface and a temperature sensor on the lower surface which is in thermal conductive contact with the back surface of the bottom plate. For the configuration that introduces cold air whose amount is adjusted,
The first step of measuring the time from the start of thawing until the temperature sensor rises to a predetermined temperature, the time storage means for storing the time measured by the first timer, and the first step of the radiant heater. The first duty ratio setting means for setting the duty ratio, the second timer for setting the time of the second stage, the temperature storage means for storing the temperature of the temperature sensor at the end of the second stage, and the radiant heater A second duty ratio setting means for setting the duty ratio of the second stage, a memory for storing a control rule based on an empirical rule for obtaining the time of the third stage, and a memory for the first stage stored in the time storage means. A fuzzy logic operation is performed based on the time and the temperature at the end of the second stage stored in the temperature storage means and the control rule retrieved from the memory.
A fuzzy inference processor for calculating the time of the stage, a third timer for setting the time of the third stage calculated by the fuzzy inference processor, and a third duty ratio setting means for setting the duty ratio of the radiant heater of the third stage And the radiant heater control means for controlling the radiant heater based on the signals of the first, second and third duty ratio setting means, the fan is forced to operate, and the damper device is forcedly released in the first stage, and the second The stage is provided with a control means for forcibly closing.

In addition, a finish setting switch for inputting the user's preference for designation of the finished state of thawing, for example, stiffening or softening according to the preference of the user, and the input of the finish setting switch A plurality of memories for storing a control rule based on an empirical rule for obtaining the time of three stages,
There is provided a finish selecting means for judging which one of the plurality of memories should be selected according to the state of the setting switch.

[0010]

According to the present invention, due to the above structure, indirect radiation is performed through the upper surface and the reflecting surface of the food to be thawed, and the food to be thawed absorbs heat almost uniformly.

The fan is forcibly operated during thawing,
As a first step, the radiant heater is energized at the energization rate set by the first energization rate setting means from the start of thawing until the temperature sensor rises to a predetermined temperature, and the damper device is opened to cool the air. be introduced. In the second stage, the radiant heater is energized for a certain period of time at the duty ratio set by the second duty ratio setting means, and the damper device is closed to suppress the inflow of cold air.

Then, based on the time required for the first step, the temperature at the end of the second step, and the control rule fetched from the memory, a fuzzy logic operation is performed by a fuzzy inference processor to obtain a third duty ratio. And a third timer time is required. Therefore, the duty ratio and the timer time obtained as described above are used to find the optimum duty ratio and the timer time according to the size and weight of the food to be thawed and the preference of the user, and there is little unevenness in thawing, and the thawing can be done in a short time with peace of mind. Is something that can be done.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A defrosting control apparatus showing an embodiment of the present invention will be described below with reference to FIGS. In FIG.
8 is a refrigerator body, an outer box 9, an inner box 10 and both boxes 9,
It is composed of a heat insulating material 11 filled in the space 10.
Reference numeral 12 is a cooling room (hereinafter, referred to as refrigerating room 12), and 13
Is a freezing compartment defined above the refrigerating compartment 12. 15
Is a compressor of the refrigeration cycle provided at the bottom of the refrigerator body 8,
Reference numeral 16 is a cooler provided on the back surface in the freezer compartment 13.

Reference numeral 17 denotes a fan for forcibly ventilating the cool air cooled by the cooler 16 into the refrigerating compartment 12, the freezing compartment 13 and the thawing compartment 14, and 18 is provided at the inlet of the thawing compartment 14 to inflow cold air by an electric input. It is a damper device that opens and closes to adjust the amount.

Reference numeral 21 is a thaw chamber 14 for cooling the cool air from the fan 17.
The reference numeral 22 is a discharge duct, and 22 is a suction duct for returning the cold air that has cooled the inside of the thawing chamber 14 to the cooler 16.

Reference numeral 23 is a freezing room temperature sensor for detecting the temperature of the freezing room 13, and 24 is a defrosting room temperature sensor.

Next, the detailed structure of the thawing chamber 14 is shown in FIG.
This will be described with reference to FIG. 25 is a synthetic resin outer box, 26
Is an inner box made of metal such as aluminum, and has a curved reflection plate 27 and a bottom plate 2 arranged below the reflection plate 27 so as to face each other.
8 and both plates 27 and 28 are connected to each other at three sides by a substantially U-shaped side plate 29. In addition, the thawing room temperature sensor 24
Are thermally conductively attached to the vicinity of the central portion of the back surface of the bottom plate 28. Reference numeral 30 denotes a door that is openably and closably provided at the front opening of the inner box 26, and has a double structure made of synthetic resin that forms an air layer to improve heat insulation. Reference numeral 31 is a radiant heater made of a quartz glass tube, which is provided facing the reflection plate 27 of the inner box 26 at a predetermined interval, and radiates far infrared rays of about 5 μm or more by itself. The emission efficiency of far infrared rays may be further enhanced by baking and coating a ceramic paint containing as a main component.

Reference numeral 33 denotes a thawing dish which is detachably installed on the bottom plate 28 and on which the food to be thawed 34 is placed. Reference numeral 35 denotes a protective net for preventing burns which is attached so as to cover the radiant heater 31 at a constant interval. Reference numeral 37 is a heat insulating material inserted between the outer box 25 and the inner box 26, and has a discharge air passage 38 communicating with the discharge duct 21 and the damper device 18 at the upper portion, and a suction air passage 39 communicating with the suction duct 22 at the rear portion. Is forming. Four
0 is a discharge port formed in a large number on the reflection plate 27 of the inner box 26 so as to connect the inside of the thawing chamber 14 and the discharge air passage 38, and 41 is a inside of the inner box 26 so that the inside of the thawing chamber 14 and the suction air passage 39 are connected. It is a suction port formed in the side plate 29.

Further, in FIG. 5, 42 is the refrigerator main body 8
It is an operation plate provided on a part of the outer shell of the user, and the finished state desired by the user (eg, "hard", "standard", "soft")
A finish setting switch 43 (in this case, “standard” if nothing is set) and a defrosting switch 44 for starting or stopping the defrosting operation are provided.

Next, the control relationship will be described with reference to FIG. Decompression control means 50 is stage control means 51, first
Timer 52, second timer 53, third timer 54,
First duty ratio setting means 55, second duty ratio setting means 5
6, third electrification rate setting means 57, time storage means 58, temperature storage means 59, fuzzy inference processor 60, first memory 61, second memory 62, third memory 63, finish selection means 64, heater It is composed of control means 65 and damper control means 66.

Reference numeral 67 is a defrosting chamber temperature detecting means for converting the temperature of the defrosting chamber temperature sensor 24 into an electric signal, and 68 is freezing chamber temperature detecting means for converting the temperature of the freezing chamber temperature sensor 23 into an electric signal.

Numeral 69 is a refrigerator control means for controlling the compressor 15 by a signal from the freezing room temperature detecting means 68, and a fan 17 by a signal from the freezing room temperature detecting means 68 and the defrosting control means 50.
To control. This is because if the temperature of the freezer rises, the compressor 1
5 and the fan 17 are operated, and if the temperature drops, the compressor 15
The fan 17 is controlled to be stopped, but the fan 17 is forcibly operated when the defrosting is started.

The stage control means 51 judges whether or not the defrosting switch has been pushed, and if pushed, the defrosting control is started, and the first timer 52, the first duty ratio setting means 55, and the second duty ratio setting means 55 are set in accordance with each stage. Timer 53 and second duty ratio setting means 5
6, the operation signal is sent to the third timer 54 and the first duty ratio setting means 57. Further, the stage control means 51 notifies the refrigerator control means 69 that the thawing is started, the damper control means 66 to notify each stage, and the damper control means 6
Reference numeral 6 controls the damper device 18.

The first timer 52 regulates the time of the first stage, and operates by the operation signal of the stage control means 51, and continues the timer operation until the defrosting chamber temperature detecting means 67 reaches the set temperature. The first duty ratio setting means 55 sets the duty ratio of the radiant heater 31 in the first stage.

The second timer 53 regulates the time of the second stage, and the operating time is set in advance, and the second duty ratio setting means 56 sets the duty ratio of the radiant heater 31 in the second stage. Has been done.

The third timer 54 regulates the time of the third stage, and the operating time is preset. The third duty ratio setting means 57 is defined by the duty ratio of the radiant heater 31 at the third stage, and the duty ratio is the time storing means 58 for storing the time of the first stage and the time when the second stage is completed. Temperature storage means 59 for storing the temperature of the defrosting chamber, and a first memory 61 for storing a control rule based on an empirical rule for obtaining the energization rate, which corresponds to the finish state desired by the user set by the finish switch 43. , The second memory 62 and the third memory 63, the fuzzy logic operation result is set by the fuzzy inference processor 60 based on the control rule extracted from the memory selected by the finish selecting unit 64.

The heater control means 65 controls the radiant heater 31 at the duty ratios set in the operating duty ratio setting means 55, 56 and 57. At this time, the duty factor is on / off
Not only the control but also the conversion of the electric power of the heater such as phase control may be performed.

The operation of the above arrangement will be described with reference to the flow chart shown in FIG.

First, the food to be thawed (for example, beef steak meat having a thickness of 20 mm) 34 to be thawed is placed on the thaw plate 33 at approximately the center and placed on the bottom plate 26. First, in STEP 1, the defrosting control is started by turning on the defrosting switch 44. When the thawing control is started, in STEP 2, the stage control means 51 outputs the operation signals of the first timer 52 for measuring the time of the first stage and the first duty ratio setting means 55. Then, the first timer 52
Starts the time counting, and the heater control means 65 causes the radiant heater 3 to operate at the duty ratio set by the first duty ratio setting means 55.
Control 1 In this embodiment, the energization rate is set to 100%, and the radiant heater 31 is energized continuously.

Next, in STEP 3, the stage control means 51
Sends to the refrigerator control means 69 that defrosting has started as a defrosting signal, and the refrigerator control means 69 forcibly operates the fan 17. Then, in STEP 4, the damper device 18 is forcibly opened. Therefore, it is mainly 5 μm from the top surface.
Since the above far infrared rays are continuously and directly or almost indirectly radiated to the food to be defrosted 34 through the reflecting plate 25, in general food products having an absorption wavelength band in the far infrared wavelength range. Far infrared rays are efficiently absorbed, and the heat quickly penetrates into the inside of the food to be defrosted 34. By such continuous heating, the temperature of the food to be defrosted 34 that was in a frozen state (for example, -20 ° C) in the first stage can be quickly raised.

On the other hand, the cool air cooled by the cooler 16 is guided to the discharge air passage 38 in the thawing chamber 14 through the discharge duct 21 in the refrigerator body and the damper device 18 by the forced air blowing action of the fan 17. The air is descended and blown like a shower from a large number of discharge ports 40 on the surface. Therefore, the radiant heater 31 described above is used.
In addition to the effect of heat permeation into the food due to the far-infrared radiation, the thawing proceeds in a state where the temperature unevenness between the surface and the center of the food to be defrosted 34 does not increase while suppressing the surface temperature rise. In addition, the air warmed by the heating action in the thawing chamber 14 is returned to the cooler 16 from the suction port 41 and the suction air passage 40 provided at the rear part of the room through the suction duct 22 of the refrigerator body 8 and cooled again. Repeat the circulation.

While the continuous heating action including such cooling action proceeds, if it is determined in STEP 5 whether the temperature of the thaw chamber temperature sensor 24 is higher or lower than the set value (for example, 15 ° C.), the higher temperature is set in STEP 5. Wait until

When it is judged in STEP 5 that the temperature is high (15 ° C. or higher), it is judged that the first stage is completed, and STEP 6
The time storage means 58 stores the time L1 required for the first step.
Stored in the first timer 52 and the first duty ratio setting means 5
Stop 5 Here, the required time L1 is almost proportional to the area of the food.

Next, in STEP 7, the stage control means 51 sets the time of the second stage (for example, 5 minutes).
The timer 53 and the operation signal of the second duty ratio setting means 56 are output. Then, the second timer 53 starts counting time, and the heater control means 65 controls the radiant heater 31 at the duty ratio set by the second duty ratio setting means 56.
In this embodiment, the energization rate is set to 0% and the radiant heater 31
Is stopped. Then, in STEP 8, the damper device 18 is forcibly closed.

Then, in STEP 9, the second timer 53
Waits until the timer finishes counting, then STEP1
0, the temperature T2 of the thaw chamber sensor 24 at the end of the second stage
Is stored in the temperature storage means 59, and the second timer 53, the second
The duty ratio setting means 56 is stopped.

In this way, the heating action and the cold air blowing are interrupted so that the temperature of the food to be thawed 34 is easily transmitted to the thaw chamber temperature sensor 24, and T2 indirectly detects the weight of the food to be thawed.

Next, the time L1 required for the first stage measured in STEP 11 is input to the fuzzy inference processor 60. Next, in STEP 12, the temperature T2 of the thaw chamber temperature sensor 24 at the end of the second stage is the fuzzy inference processor 6
Input to 0.

Then, in STEP 13, the finish selection means 64 judges the finish state input by the user with the finish setting switch 43, and in STEP 14, the memory storing the control rule corresponding to the finish setting is selected. Here, the first memory 61 corresponds to the standard, the second memory 62 corresponds to the harder, and the third memory 63 corresponds to the softer. And STE
In P15, the fuzzy inference processor 60 takes out the control rule stored in the first memory 61 if it is a standard setting, and obtains the energization rate D of the radiant heater 31 in the third stage by fuzzy inference.

From this, the third duty ratio setting means 57
Conductivity D obtained by the fuzzy inference processor 60
Is set (STEP 16). And STEP17
Then, the stage control means 51 outputs the operation signals of the third timer 54 which sets the time of the third step and the third duty ratio setting means 57. The third duty ratio setting means 57 is ST
The heater control means 65 controls the radiant heater 31 at the energization rate D set in EP16. Then, in STEP 18, the damper device 18 is forcibly opened.

Then, in STEP 19, the third timer 5
Wait until 4 finishes counting time, and after that, STEP
20, the stage control means 51 controls the refrigerator control means 6
The sending of the defrosting signal to 9 is stopped, and the refrigerator control means 69 releases the forced operation of the fan 17. Further, the stage control means 51 controls the damper device 18 via the damper control means 66 so as to stop the control of the forced opening or the forced closing of the damper device 18 and maintain the defrosting chamber 14 at a constant temperature, for example, −3 ° C. Then, in STEP 21, the thawing is completed.

Here, the fuzzy inference for obtaining the optimum duty ratio D of the radiant heater 31 in the third stage is executed based on the following control rule.

The control rules adopted in the first memory 61 of this embodiment are the following nine rules. For example, rule 1: If the time of the first stage is short and the temperature of the second stage is low, set the conduction rate to the middle level.

Rule 2: If the time of the first stage is short,
If the temperature in the second stage is moderate, reduce the duty ratio slightly.

Rule 3: If the time of the first stage is short,
If the temperature in the second stage is high, reduce the duty ratio. ··· Rule 7: If the time of the first stage is long and the temperature of the second stage is low, increase the duty ratio.

Rule 8: If the time of the first stage is long,
If the temperature in the second stage is moderate, increase the duty ratio slightly.

Rule 9: If the time of the first stage is long,
If the second stage temperature is high, set the duty ratio to the middle level. Etc.

This is because as the area of the food 34 to be defrosted increases, the time of the first step becomes longer. Therefore, as the time of the first step becomes longer, it becomes more difficult for heat to be transferred and it becomes difficult to thaw, and it is necessary to increase the electrical conductivity. There is. Also, the food to be thawed food 34
The larger the value of, the lower the temperature of the second stage. Therefore, the lower the temperature of the second stage is, the larger the load is, and the larger the duty ratio is.

Therefore, the above-mentioned language rule is a control rule which can be set from the experimental data so as to set the optimum energization rate, and the relation between the first stage time L and the second stage temperature T Is shown in (Table 1).

[0049]

[Table 1]

(Table 1) is a table showing the relationship of the control rules. The time L of the first step is three steps (BL = large, M) in the horizontal direction.
L = medium, SL = small), and the temperature T of the second stage in the vertical direction
Are arranged in three stages (HT = high, MT = medium, LT = low), and the first stage time L and the second stage temperature T, which are divided as described above, are located at respective intersecting positions. The optimum current-carrying ratio D corresponding to the first stage time L and the second stage temperature T is arranged.

When the language rule is stored in the first memory 61 of FIG. 1, it is stored according to the following rule rule. The control rules adopted in this embodiment are nine.

Rule 1: IF L is SL and T is LT THEN D is M Rule 2: IF L is SL and T is MT THEN D IS MS Rule 3: IF L is SL and T is HT THEN D is S. -Rule 7: IF L is BL and T is LT THEN D is B rule 8: IF L is BL and T is MT THEN D IS MB rule 9: IF L is BL and T is HT THEN D is M control rule 1, In the rules 2, ..., Rule 9, since the time L of the first stage, the temperature T of the second stage, and the duty ratio D are determined stepwise as shown in (Table 1), detailed control is possible. When performing, the time L of the first step actually measured in the middle of each step of the time L of the first step and the temperature T of the second step
In the temperature T2 of 1 and the second stage, the antecedent part (I
Calculate the degree to which the F part) is satisfied,
It is necessary to estimate the energization rate D at the set temperature according to the degree. Therefore, in this embodiment, the degree is calculated by using the membership function of the fuzzy variable with respect to the time L of the first stage and the temperature T of the second stage.

FIG. 7A shows the membership function μS of the fuzzy variables SL, ML and BL with respect to the time L in the first stage.
7 shows L (L1), μML (L1), μBL (L1), and FIG. 7B shows the membership function μL of the fuzzy variables LT, MT, HT with respect to the temperature T in the second stage.
It shows T (T2), μMT (T2), and μHT (T2).

The fuzzy inference executed by the fuzzy inference processor 60 is a fuzzy logic operation using the control rules 1, rules 2, ..., Rule 9 and the membership functions of FIGS. 7 (a) and 7 (b). The third-stage duty factor calculation is performed.

The procedure of fuzzy inference in STEP 15 of FIG. 6 will be described below with reference to the flowchart of FIG.

In STEP 30, the fuzzy inference processor 60 causes the first stage time L 1 and the second stage temperature T
Using the membership function of fuzzy variables for 2,
The membership value (indicated as M value in the figure) at the first stage time L1 and the second stage temperature T2 is calculated.

In STEP 31, the degree to which the membership values of the fuzzy variables for the obtained first stage time L1 and second stage temperature T2 satisfy the antecedent part of each of the nine rules is described below. It is calculated by the synthetic method as follows.

In the figure, the fuzzy variable with respect to the time L in the first stage is indicated by A, and the fuzzy variable with respect to the temperature T in the second stage is indicated by B.

Rule 1: h1 = μSL (L1) ∩μLT (T2)
= ΜSL (L1) × μLT (T2) --- (1) Rule 2: h2 = μSL (L1) ∩μMT (T2)
= ΜSL (L1) × μMT (T2) --- (2) Rule 3: h2 = μSL (L1) ∩μHT (T2)
= ΜSL (L1) × μHT (T2) --- (2) ... Rule 7: h7 = μBL (L1) ∩μLT (T2)
= ΜBL (L1) × μLT (T2) ----- (7) Rule 8: h8 = μBL (L1) ∩μMT (T2)
= ΜBL (L1) × μMT (T2) --- (8) Rule 9: h9 = μBL (L1) ∩μHT (T2)
= ΜBL (L1) × μHT (T2) ----- (9) In the formula (1), L1 is the region SL with respect to the time L of the first stage.
And T2 is the region L for the temperature T of the second stage
The proposition of entering T means that the value of the product of the ratio of L1 entering SL and the ratio of T2 entering LT is satisfied, that is, the antecedent part of rule 1 is satisfied at the ratio of h1. Similarly, in the case of rules 2, ..., Rule 9, which are expressions (2), ..., (9), the antecedent parts are h2 and h2, respectively.
..., which means that it is established at the ratio of h9.

In STEP 32, the time L1 of the first stage and the second time are determined by the membership function of the execution part of the control rule.
The energization rate D of the third stage at the stage temperature T2 is obtained as follows. The duty ratio D is calculated by using the height method, which is one of the one-point conversion methods, as the value of the weighted average of the proportions h1, h2, ..., H9 in which the antecedent part of each control rule holds (Equation 1). Calculate as shown in.

[0061]

[Equation 1]

As a result, the third-stage energization rate D is obtained. Further, the control rule adopted in the second memory 62 of the present embodiment corresponds to a hard finish, so the first rule
The control rule adopted in the first memory 61 is lower than the control rule adopted in the first memory 61 because the conduction rate is lower than that of the first memory 61. , The energization rate is high and the second
The control rule adopted in the memory 62 is rule 1: If the time of the first step is short and the temperature of the second step is low, reduce the duty ratio slightly.

Rule 2: If the time of the first stage is short,
If the temperature in the second stage is moderate, reduce the duty ratio.

Rule 3: If the time of the first stage is short,
If the temperature of the second stage is high, make the duty ratio very small.・ ・ ・ Rule 7: If the temperature of the first stage is long and the temperature of the second stage is low, increase the duty factor slightly.

Rule 8: If the time of the first stage is long,
If the temperature in the second stage is medium, set the duty ratio to medium.

Rule 9: If the time of the first stage is long,
If the temperature in the second stage is high, reduce the duty ratio slightly.
Etc.

The control rule adopted in the third memory 63 is rule 1: If the time of the first step is short and the temperature of the second step is low, increase the duty ratio slightly.

Rule 2: If the time of the first stage is short,
If the temperature in the second stage is medium, set the duty ratio to medium.

Rule 3: If the time of the first stage is short,
If the temperature in the second stage is high, reduce the duty ratio slightly.・ ・ ・ Rule 7: If the time of the first stage is long and the temperature of the second stage is low, increase the duty ratio to a very large value.

Rule 8: If the time of the first stage is long,
If the second stage temperature is moderate, increase the duty ratio.

Rule 9: If the time of the first stage is long,
If the temperature in the second stage is high, increase the duty ratio slightly. Etc.

Therefore, in this embodiment, the first stage time and the second stage temperature are used as the control parameters, and the optimum radiant heater 3 is selected according to the area and size of the food to be defrosted 34.
Defrosting can be performed at a duty ratio of 1, and fine control is possible.

Further, since the control rule for inferring the energization ratio is switched by setting the finish state, it is possible to obtain the finish state preferred by the user.

Next, another embodiment will be described with reference to the drawings. Further, in the figure, the same components as those in the conventional example and the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted. The structure of the refrigerator and the structure of the thawing chamber 14 shown in FIGS. 2 to 5 are the same as those of the first embodiment.

In FIG. 9, reference numeral 70 denotes a defrosting control means, which is a stage control means 51, a first timer 52, and a second timer 5.
3, third timer 71, first duty ratio setting means 55, second duty ratio setting means 56, third duty ratio setting means 72,
Time storage means 58, temperature storage means 59, fuzzy inference processor 80, first memory 81, second memory 82,
The third memory 83, finish selection means 64, heater control means 65, and damper control means 66 are included.

The third duty ratio setting means 72 defines the duty ratio of the radiant heater 31 in the third stage, and the duty ratio is set in advance. The third timer 71 regulates the time of the third stage, and the timer time is the temperature storing means 58 for storing the time of the first stage and the temperature for storing the defrosting chamber temperature when the second stage is completed. A storage unit 59, a first memory 71, a second memory 82, which stores a control rule based on an empirical rule for obtaining a duty ratio, which corresponds to a finish state desired by the user set by the finish switch 43.
It is set by the fuzzy logic operation result in the fuzzy inference processor 80 based on the control rule fetched from the memory selected by the finish selecting means 64 in the third memory 83.

In such a structure, the operation will be described with reference to the flowchart shown in FIG.

First, the food 34 to be thawed to be thawed is placed on the bottom plate 26 by placing it on the thaw plate 33 at approximately the center thereof. Then, first in STEP 1, the defrosting switch 4
When 4 is turned on, the thawing action is started. When the thawing control starts, in STEP 2, the stage control means 5
1 outputs the operation signal of the 1st timer 52 which measures the time of the 1st step, and the 1st duty ratio setting means 55. Then, the first timer 52 starts time counting, and the heater control means 65 controls the radiant heater 31 at the duty ratio set by the first duty ratio setting means 55. In this embodiment, the duty factor is 10
It is set to 0%, and the radiant heater 31 is continuously energized.

Next, in STEP 3, the stage control means 51
Sends to the refrigerator control means 69 that defrosting has started as a defrosting signal, and the refrigerator control means 69 forcibly operates the fan 17. Then, in STEP 4, the damper device 18 is forcibly opened. Therefore, it is mainly 5 μm from the top surface.
Since the above far infrared rays are continuously and directly or almost indirectly radiated to the food to be defrosted 34 through the reflecting plate 25, in general food products having an absorption wavelength band in the far infrared wavelength range. Far infrared rays are efficiently absorbed, and the heat quickly penetrates into the inside of the food to be defrosted 34. By such continuous heating, the temperature of the food to be defrosted 34, which was frozen in the first stage, can be quickly raised.

On the other hand, the cool air cooled by the cooler 16 is guided to the discharge air passage 38 in the thawing chamber 14 through the discharge duct 21 in the refrigerator body and the damper device 18 by the forced air blowing action of the fan 17. The air is descended and blown like a shower from a large number of discharge ports 40 on the surface. Therefore, the radiant heater 31 described above is used.
In addition to the effect of heat permeation into the food due to the far-infrared radiation, the thawing proceeds in a state where the temperature unevenness between the surface and the center of the food to be defrosted 34 does not increase while suppressing the surface temperature rise. In addition, the air warmed by the heating action in the thawing chamber 14 is returned to the cooler 16 from the suction port 41 and the suction air passage 40 provided at the rear part of the room through the suction duct 22 of the refrigerator body 8 and cooled again. Repeat the circulation.

While the continuous heating action including such cooling action proceeds, it is determined in STEP 5 whether the temperature of the thaw chamber temperature sensor 24 is higher or lower than the set value, and if it is low, the STE
Wait until it gets higher at P5.

When it is determined in STEP 5 that the temperature is high, it is determined that the first stage has ended, and the process proceeds to STEP 6 in which the time L1 required for the first stage is stored in the time storage means 58, and the timer 52, the first The duty factor setting means 55 is stopped. Here, the required time L1 is almost proportional to the area of the food.

Next, in STEP 7, the stage control means 51 causes the second timer 53 to set the second stage time.
Then, the operation signal of the second duty ratio setting means 56 is output.
Then, the second timer 53 starts counting time, and the heater control means 65 controls the radiant heater 31 at the duty ratio set by the second duty ratio setting means 56. In this embodiment, the energization rate is set to 0% and the radiant heater 31 is stopped. Then, in STEP 8, the damper device 18 is forcibly closed.

Then, in STEP 9, the second timer 53
Waits until the timer finishes counting, then STEP1
0, the temperature T2 of the thaw chamber sensor 24 at the end of the second stage
Is stored in the temperature storage means 59, and the second timer 53, the second
The duty ratio setting means 56 is stopped.

In this way, the heating action and cold air blowing are interrupted, and the temperature of the food to be thawed 34 is easily transmitted to the thaw chamber temperature sensor 24, and T2 indirectly detects the weight of the food to be thawed.

Next, the time L1 required for the first stage measured in STEP 41 is input to the fuzzy inference processor 80. Next, in STEP 42, the temperature T2 of the thawing chamber temperature sensor 24 at the end of the second stage is the fuzzy inference processor 8
Input to 0.

Then, in STEP 13, the finish selection means 64 determines the finish state input by the user with the finish setting switch 43, and in STEP 14, the memory storing the control rule corresponding to the finish setting is selected. Here, the first memory 71 corresponds to the standard, the second memory 82 corresponds to the harder, and the third memory 83 corresponds to the softer. And STE
In P43, the fuzzy inference processor 80 takes out the control rule stored in the first memory 71 if it is a standard setting, and obtains the third-stage timer time TM by fuzzy inference.

As a result, the third timer 71 is set to the timer time TM obtained by the fuzzy inference processor 80 (STEP 44). Then, in STEP 17, the stage control means 51 sets the time of the third stage to the third stage.
The timer 71 and the operation signal of the third duty ratio setting means 72 are output. Then, the third duty ratio setting means 72 controls the radiant heater 31 by the heater duty controlling means 65 at the set duty ratio. Then, in STEP 18, the damper device 18 is forcibly opened.

Then, in STEP 19, the third timer 7
1 counts the time and waits until the time set in STEP44 is reached, and then proceeds to STEP20 where the stage control means 51 stops sending the defrosting signal to the refrigerator control means 69, and the refrigerator control means 69 causes the fan 17 to operate. Cancel the forced operation. Further, the stage control means 51 stops the control of the forced opening or the forced closing of the damper device 18 to stop the decompression chamber 1.
The damper device 18 is controlled via the damper control means 66 so as to maintain 4 at a constant temperature, for example, −3 ° C. And S
Thawing is completed at TEP21.

Here, the fuzzy inference for obtaining the timer time TM in the third step is executed based on the following control rule.

The control rules adopted in the first memory 71 of this embodiment are the following nine rules. For example, rule 1: If the time of the first stage is short and the temperature of the second stage is low, set the timer time to the middle level.

Rule 2: If the time of the first stage is short,
If the second stage temperature is moderate, shorten the timer time slightly.

Rule 3: If the time of the first stage is short,
If the second stage temperature is high, shorten the timer time. ··· Rule 7: If the first stage time is long and the second stage temperature is low, increase the timer time.

Rule 8: If the time of the first stage is long,
If the second stage temperature is medium, increase the timer time slightly.

Rule 9: If the time of the first stage is long,
If the second stage temperature is high, set the timer time to the middle level.
Etc.

This is because as the area of the food 34 to be defrosted increases, the time of the first step becomes longer. Therefore, the longer the time of the first step, the less heat is transmitted and the more difficult it is to thaw.
It is necessary to increase the step timer time. Further, as the size of the food to be thawed 34 becomes larger, the temperature of the second stage becomes lower. Therefore, the lower the temperature of the second stage becomes, the larger the load becomes, and the timer time of the third stage needs to be increased. It is a rule obtained from such experience.

Therefore, the above-mentioned language rule is a control rule that can be set from the experimental data to set the optimum timer time, and the relation between the first stage time L and the second stage temperature T Is shown in (Table 2).

[0098]

[Table 2]

(Table 2) is a table showing the relationship of the control rules. The time L of the first step is three steps (BL = large, M) in the horizontal direction.
L = medium, SL = small), and the temperature T of the second stage in the vertical direction
Are arranged in three stages (HT = high, MT = medium, LT = low), and the first stage time L and the second stage temperature T, which are divided as described above, are located at respective intersecting positions. Optimal timer time T corresponding to the first stage time L and the second stage temperature T
M is arranged.

When the language rules are stored in the first memory 71 shown in FIG. 1, they are stored according to the following rule rule. The control rules adopted in this embodiment are nine.

Rule 1: IF L is SL and T is LT THEN TM is M Rule 2: IF L is SL and T is MT THEN TM is is MS Rule 3: IF L is SL and T is HT THEN TM is S. -Rule 7: IF L is BL and T is LT THEN TM is L rule 8: IF L is BL and T is MT THEN TM is is ML rule 9: IF L is BL and T is HT THEN TM is M control rule 1, In the rules 2, ..., Rule 9, since the first stage time L, the second stage temperature T, and the timer time TM are determined stepwise as shown in (Table 2), detailed control is possible. In the case of performing
At the time L1 of the first step and the temperature T2 of the second step in the middle of each step of the step temperature T, the degree to which the antecedent part (IF section) of the control rule is satisfied is calculated, It is necessary to estimate the timer time TM of the set temperature according to the degree. Therefore, in this embodiment, the degree is calculated by using the membership function of the fuzzy variable with respect to the time L of the first stage and the temperature T of the second stage.

FIG. 11A shows the membership function μ of the fuzzy variables SL, ML and BL with respect to the time L in the first stage.
11 shows SL (L1), μML (L1), μBL (L1), and FIG. 11B shows the membership function μLT (T2) of the fuzzy variables LT, MT, HT with respect to the temperature T in the second stage. , ΜMT (T2), μHT (T2) are shown.

The fuzzy inference executed by the fuzzy inference processor 80 is a fuzzy logic operation using the control rules 1, rules 2, ..., Rule 9 and the membership functions of FIGS. 11 (a) and 11 (b). The timer time of the third stage is calculated.

The procedure of fuzzy inference in STEP43 of FIG. 10 will be described below with reference to the flowchart of FIG.

At STEP 30, the fuzzy inference processor 80 causes the first stage time L 1 and the second stage temperature T
Using the membership function of fuzzy variables for 2,
The membership value (indicated as M value in the figure) at the first stage time L1 and the second stage temperature T2 is calculated.

In STEP31, the degree to which the membership values of the fuzzy variables for the obtained first stage time L1 and second stage temperature T2 satisfy the antecedent part of each of the nine rules is described below. It is calculated by the synthetic method as follows.

In the figure, the fuzzy variable for the time L in the first step is indicated by A, and the fuzzy variable for the temperature T in the second step is indicated by B.

Rule 1: h1 = μSL (L1) ∩μLT (T2)
= ΜSL (L1) × μLT (T2) --- (1) Rule 2: h2 = μSL (L1) ∩μMT (T2)
= ΜSL (L1) × μMT (T2) --- (2) Rule 3: h2 = μSL (L1) ∩μHT (T2)
= ΜSL (L1) × μHT (T2) --- (2) ... Rule 7: h7 = μBL (L1) ∩μLT (T2)
= ΜBL (L1) × μLT (T2) ----- (7) Rule 8: h8 = μBL (L1) ∩μMT (T2)
= ΜBL (L1) × μMT (T2) --- (8) Rule 9: h9 = μBL (L1) ∩μHT (T2)
= ΜBL (L1) × μHT (T2) ----- (9) In the formula (1), L1 is the region SL with respect to the time L of the first stage.
And T2 is the region L for the temperature T of the second stage
The proposition of entering T means that the value of the product of the ratio of L1 entering SL and the ratio of T2 entering LT is satisfied, that is, the antecedent part of rule 1 is satisfied at the ratio of h1. Similarly, in the case of rules 2, ..., Rule 9, which are expressions (2), ..., (9), the antecedent parts are h2 and h2, respectively.
..., which means that it is established at the ratio of h9.

At STEP 32, the time L1 of the first stage and the second time are determined by the membership function of the execution part of the control rule.
The timer time TM of the third stage at the stage temperature T2 is obtained as follows. The timer time TM is calculated by using the height method, which is one of the one-point conversion methods, as the value of the weighted average of the proportions h1, h2, ..., H9 in which the antecedent part of each control rule holds (Equation 2). Calculate as shown in.

[0110]

[Equation 2]

As a result, the timer time TM of the third stage is obtained. Further, since the control rule adopted in the second memory 82 of the present embodiment corresponds to a hard finish,
Since the timer time is set lower than that of the control rule adopted in the first memory 71 and the finished rule of the control rule adopted in the third memory 83 is soft, the control adopted in the first memory 71 is controlled. The timer time is set higher than the rule, and the control rule adopted in the second memory 82 is rule 1: If the time of the first step is short and the temperature of the second step is low, shorten the timer time slightly.

Rule 2: If the time of the first stage is short,
If the second stage temperature is moderate, shorten the timer time.

Rule 3: If the time of the first stage is short,
If the second stage temperature is high, make the timer time very short.・ ・ ・ Rule 7: If the time of the first stage is long and the temperature of the second stage is low, increase the timer time slightly.

Rule 8: If the time of the first stage is long,
If the second stage temperature is medium, set the timer time to medium.

Rule 9: If the time of the first stage is long,
If the second stage temperature is high, shorten the timer time slightly. Etc.

The control rule adopted in the third memory 83 is rule 1: If the time of the first step is short and the temperature of the second step is low, increase the timer time slightly.

Rule 2: If the time of the first stage is short,
If the second stage temperature is medium, set the timer time to medium.

Rule 3: If the time of the first stage is short,
If the second stage temperature is high, shorten the timer time slightly. ··· Rule 7: If the time of the first stage is long and the temperature of the second stage is low, make the timer time very long.

Rule 8: If the time of the first stage is long,
If the second stage temperature is moderate, increase the timer time.

Rule 9: If the time of the first stage is long,
If the second stage temperature is high, increase the timer time slightly. Etc.

Therefore, in this embodiment, the time of the first stage and the temperature of the second stage are used as the control parameters, and the optimum time of the third stage is deduced by deducing the optimum time of the third stage from the area and size of the food 34 to be thawed. Can be performed, and fine control is possible.

Further, since the control rule for inferring the timer time is switched by setting the finish state, it is possible to obtain the finish state that the user likes.

[0123]

As described above, according to the present invention, a fan for forcibly ventilating the thawing chamber, a damper device provided at the inlet of the thawing chamber for adjusting the amount of cold air inflow, a thawing switch for starting the thawing action, and a thawing process The first step is to measure the time from the start of thawing until the temperature sensor rises to a predetermined temperature.
Timer and the time storage means for storing the time measured by the first timer, the first duty ratio setting means for setting the duty ratio of the first stage of the radiant heater, and the time for the second stage. A second timer, temperature storage means for storing the temperature of the temperature sensor at the end of the second step, second energization rate setting means for setting the second step energization rate of the radiant heater, and time storage means. With respect to the input of the finish setting switch for inputting the time of the first stage and the temperature at the end of the second stage stored in the temperature storage means, the finish of the food to be defrosted desired by the user, and the finish setting switch. A plurality of memories for storing a control rule based on an empirical rule for obtaining the duty ratio of the radiant heater in the third stage; and a finish selecting means for judging which of the plurality of memories should be selected according to the state of the setting switch. , Based on the control rule extracted from the memory, the fuzzy logic operation is performed to calculate the duty ratio of the radiant heater in the third stage, and the duty ratio of the radiant heater in the third stage calculated by the fuzzy inference processor is calculated. Radiant heater control for controlling the radiant heater based on the signals from the third duty ratio setting means to be set, the third timer to set the time of the third stage, and the first, second and third duty ratio setting means. Means and forced operation of the fan,
The damper device has a control means for forcibly releasing the first stage and forcibly closing the second stage. With this configuration, the time and temperature of the first stage are stored, and the area and size of the food to be defrosted are stored. With this, it is possible to perform thawing at the optimum radiant heater energization rate, and fine control is possible.

Further, since the control rule for inferring the energization ratio is switched by setting the finish state, it is possible to obtain the finish state that the user likes.

Also, a fan for forcibly ventilating the thaw chamber,
A damper device installed at the inlet of the thawing chamber to adjust the amount of cold air flowing in, a thawing switch for starting the thawing action, and the first stage during thawing, the time from the start of thawing until the temperature sensor rises to a predetermined temperature A first timer for measurement, a time storage means for storing the time measured by the first timer, a first duty ratio setting means for setting the duty ratio of the first stage of the radiant heater, and a second stage A second timer for setting the time,
A temperature storage means for storing the temperature of the temperature sensor at the end of the second stage, and a second for setting the energization rate of the second stage of the radiant heater.
Of the duty ratio setting means, the time of the first step stored in the time storage means, the temperature at the end of the second step stored in the temperature storage means, and the finish of the food to be defrosted desired by the user. A setting switch, a plurality of memories for storing a control rule based on an empirical rule for obtaining the time of the third stage for the input of the finish setting switch, and which memory among the plurality of memories is selected depending on the state of the setting switch. A final selection means for determining whether or not, a fuzzy inference processor for performing a fuzzy logic operation based on a control rule fetched from a memory to calculate a third step time, and a third step time calculated by the fuzzy inference processor. And a third duty ratio setting means for setting the duty ratio of the radiant heater at the third stage, and first, second and third duty ratios. A radiant heater control means for controlling the radiant heater based on a signal of a constant section, fan forced operation, the forced release damper device the first stage, second stage and a control means for forcibly closing.

With this configuration, the time of the first stage and the temperature of the second stage are stored, the optimum time for the third stage can be deduced from the area and size of the food to be defrosted, and the defrosting can be carried out. It can be controlled.

Further, since the control rule for inferring the timer time is switched by setting the finish state, the finish state which the user prefers can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram of a decompression control device showing a first embodiment of the present invention.

FIG. 2 is a vertical sectional view of a refrigerator with a thawing chamber equipped with the thawing chamber of the present invention.

FIG. 3 is a perspective view of the thawing chamber of FIG.

FIG. 4 is a sectional view taken along line A-A ′ of the thawing chamber of FIG.

[Fig. 5] Enlarged view of the defrosting operation plate

FIG. 6 is a flowchart of the defrosting control according to the first embodiment of the present invention.

FIG. 7 (a) is a graph showing a membership function of a fuzzy variable with respect to time required for the first step in the first embodiment of the present invention. (B) is a second step in the first embodiment of the present invention. Graph showing membership function of fuzzy variables with respect to thawing chamber temperature at the end of

FIG. 8 is a flowchart for explaining the procedure of fuzzy inference in FIG.

FIG. 9 is a block diagram of a decompression control device showing a second embodiment of the present invention.

FIG. 10 is a flowchart of the defrosting control according to the second embodiment of the present invention.

FIG. 11 (a) is a first diagram of the second embodiment of the present invention.
The graph showing the membership function of the fuzzy variable with respect to the time required for the step (b) is a graph showing the membership function of the fuzzy variable with respect to the time required for the first step in the second embodiment of the present invention.

FIG. 12 is a perspective view of a conventional thawing box.

13 is a cross-sectional view taken along line BB of the defrosting box in FIG.

[Explanation of symbols]

 14 Thaw Chamber 17 Fan 18 Damper Device 24 Thaw Chamber Temperature Sensor 29 Radiant Heater 31 Temperature Sensor 43 Finish Setting Switch 44 Thaw Switch 51 Stage Control Means 52 First Timer 53 Second Timer 57 Third Conductivity Setting Means 58 Temperature Storage unit 59 Time storage unit 60 Fuzzy inference processor 61 First memory 62 Second memory 63 Third memory 64 Finish setting selection unit 65 Heater control unit 66 Damper control unit 69 Refrigerator control unit 71 Third timer 80 Fuzzy inference Processor 81 First memory 82 Second memory 83 Third memory

Claims (4)

[Claims] 1. A reflecting plate having a curved reflecting surface, a radiant heater provided below the reflecting plate at a predetermined interval, a bottom plate arranged to face the reflecting plate, and the bottom. A thaw chamber provided with a temperature sensor that is in thermal conductive contact with the back surface of the face plate, a cooling chamber provided with the thaw chamber as a single unit, and a fan for forcedly passing cold air cooled by a cooler into the thaw chamber. A damper device provided at the inlet of the thawing chamber to adjust the amount of cold air flowing in, a thawing switch for starting the thawing action, and a first stage during thawing, the temperature sensor rises to a predetermined temperature from the start of thawing. First timer for measuring the time until, the time storage means for storing the time measured by the first timer, and the first duty ratio setting means for setting the duty ratio of the first stage of the radiant heater And a second timer for setting the time of the second stage A temperature storage means for storing the temperature of the temperature sensor at the end of the second stage, and a second duty ratio setting means for setting a second duty ratio of the radiant heater,
A memory for storing a control rule based on an empirical rule for obtaining the energization rate of the radiant heater in the third stage, the time of the first stage stored in the time storage means, and the second time stored in the temperature storage means. Based on the temperature at the end of the stage and the control rule fetched from the memory, a fuzzy logic processor performs a fuzzy logic operation in a third stage to calculate a duty ratio of the radiant heater, and a fuzzy reasoner processor. A third duty ratio setting means for setting a duty ratio of the radiant heater in a third stage, a third timer for setting a time duration of a third stage, and the first, second and third duty ratio setting means. Radiant heater control means for controlling the radiant heater on the basis of the signal of ## EQU1 ## and the fan forcibly operating, and the damper device forcibly releases the first stage and forcibly closes the second stage. Thawing control device consisting of a stage. 2. A thaw switch for starting a thaw action,
A finish setting switch for inputting the finish of the food to be defrosted desired by the user, and a plurality of storing control rules based on an empirical rule for obtaining the energization rate of the radiant heater in the third stage with respect to the input of the finish setting switch Memory of the
The defrosting control apparatus according to claim 1, further comprising a finish selection unit that determines which one of the plurality of memories is selected according to the state of the setting switch. 3. A reflection plate having a curved reflection surface, a radiant heater provided below the reflection plate at a predetermined distance, a bottom plate arranged to face the reflection plate, and the bottom. A thaw chamber provided with a temperature sensor that is in thermal conductive contact with the back surface of the face plate, a cooling chamber provided with the thaw chamber as a single unit, and a fan for forcedly passing cold air cooled by a cooler into the thaw chamber. A damper device provided at the inlet of the thawing chamber to adjust the amount of cold air flowing in, a thawing switch for starting the thawing action, and a first stage during thawing, the temperature sensor rises to a predetermined temperature from the start of thawing. First timer for measuring the time until, the time storage means for storing the time measured by the first timer, and the first duty ratio setting means for setting the duty ratio of the first stage of the radiant heater And a second timer for setting the time of the second stage A temperature storage means for storing the temperature of the temperature sensor at the end of the second stage, and a second duty ratio setting means for setting a second duty ratio of the radiant heater.
A second memory that stores a control rule based on an empirical rule for obtaining the time of the third step, the time of the first step stored in the time storage means, and the end of the second step stored in the temperature storage means. A fuzzy logic operation is performed based on the time temperature and the control rule extracted from the memory.
A fuzzy inference processor for calculating the time of a step, a third timer for setting the time of the third step calculated by the fuzzy inference processor, and a third duty ratio for setting a duty ratio of the radiant heater in the third step The setting means, the radiant heater control means for controlling the radiant heater based on the signals from the first, second and third duty ratio setting means, and the fan are forced to operate, and the damper device has the first step. A defrosting control device comprising a control means for forcibly releasing and forcibly closing the second stage. 4. A thaw switch for starting a thaw action,
A finish setting switch for inputting the finish of the food to be defrosted desired by the user; a plurality of memories for storing a control rule based on an empirical rule for obtaining the time of the third stage for the input of the finish setting switch; 4. The defrosting control device according to claim 3, further comprising finish selection means for determining which one of the plurality of memories should be selected according to the state of the setting switch.