JP3135287B2 - Refrigerator refrigerator control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a control rule based on an empirical rule and a membership function of a fuzzy variable constituting the rule for storing refrigerated food in a refrigerated room with freshness for a long period of time. The present invention relates to a refrigerator-freezer control device that infers an opening degree of a damper and a frequency of a fan motor and outputs the result.

[0002]

2. Description of the Related Art A control device of a refrigerator-freezer includes a fan motor, a compressor, a fan motor, a compressor, and the like so as to control the temperature of each of a refrigerator room, a refrigerator room, and a vegetable room of a refrigerator-freezer (hereinafter abbreviated as a refrigerator) at a set temperature. The damper is controlled, for example, in Japanese Utility Model Laid-Open No. 54-4472, Japanese Patent Laid-Open No. 2-2987.
No. 7 discloses this.

[0003] In the following, a control apparatus for a conventional refrigerator-freezer will be described with reference to the drawings, in particular, temperature control of a refrigerator.

FIG. 6 is a block diagram showing a conventional control device for a refrigerator. In FIG. 6, reference numeral 1 denotes a refrigerator main body, which is composed of an outer box 2 and an inner box 3 and a urethane foam heat insulating material 4 formed in a gap between the two boxes, and three doors 5, 6, 7 are disposed in a front opening. ing. Doors 5, 6, and 7 are a freezer compartment 8, a refrigerator compartment 9, and a vegetable compartment 10 of the refrigerator body 1, respectively.
Are arranged corresponding to the openings.

[0005] The bottom plate 11 of the freezer compartment 8 and the top plate 12 of the refrigerator compartment 9
The evaporator 13 and a fan 14 are provided behind the evaporator 13 in the partition wall surrounded by. Further, ventilation paths 15 and 16 for introducing cooling air from the evaporator 13 into each chamber are formed at the back of the freezing chamber 8 and the refrigerator compartment 9. 17 is a compressor. Reference numeral 18 denotes a refrigerator compartment door switch that operates by opening and closing the door 6 of the refrigerator compartment 9, and 19 denotes a refrigerator compartment temperature sensor. Reference numeral 20 denotes a fan motor for driving the fan 14.

Reference numeral 21 denotes door opening / closing detecting means for detecting the opening / closing of the door 6 of the refrigerator compartment 9 based on the operation of the refrigerator compartment door switch 18, and 22 detects the temperature in the refrigerator compartment by the refrigerator compartment temperature sensor 19. This is a refrigerator temperature detecting means. 23
Is a damper for shutting off and introducing cooling air into the refrigerator compartment 9.
Reference numeral 33 denotes the opening / closing operation of the damper 23 and the turning on / off of the fan motor 20 based on the inside temperature detected by the inside temperature detecting means 22.
This is an operation means for obtaining the -off operation.

A fan 31 controls the fan motor 20 and controls the fan 1
Reference numeral 32 denotes a damper control unit for driving the damper 23, and reference numeral 39 denotes a compressor control unit for driving the compressor 17.

[0008] The operation of the control device for a refrigerator-freezer constructed as described above will be described below with reference to Figs.

FIG. 7 is a flowchart for explaining the conventional temperature control of the refrigerator compartment 9. First, the door opening / closing detecting means 21 detects the operation of the refrigerator compartment door switch 18 from the operation of the refrigerator compartment 9.
It is determined whether or not the door 6 is closed (S
step21). If the door 6 is closed, the refrigerator temperature detecting means 22 detects the refrigerator temperature Tpc in the refrigerator compartment by the refrigerator compartment temperature sensor 19 (Step 22). Then, the calculating means 33 determines whether the fan motor is on or off according to the internal temperature Tpc.
ff operation, damper opening / closing operation and compressor on-o
The ff operation is calculated (Step 23).

The fan motor control means 31 drives the fan 14 by controlling the fan motor 20.
The damper control means 32 controls the damper 23, and the compressor control means 39 controls the compressor 17 (St
ep24). As described above, the appropriate temperature of the cool air is sent to the refrigerator compartment 9 to control the temperature of the refrigerator compartment. If the door 6 is open, the fan 14 is stopped (Step 25).

[0011]

However, in the above configuration, the on-off of the fan motor is performed based on the information on only the internal temperature Tpc detected by the internal temperature detecting means 22.
off operation, damper opening / closing operation, and compressor on-
Since the off operation was calculated, it was not possible to perform a fine temperature control. For example, it is not possible to perform an optimum temperature control when food is packed or a sudden visitor wants to cool down quickly, for example, in summer. Had problems.

The present invention solves the above problems,
Heat load (hereinafter abbreviated as load) and thermal load fluctuation (hereinafter abbreviated as load fluctuation) of food in the refrigerator compartment, and the number of rotations of the fan motor and the degree of opening of the damper according to changes in the ambient temperature in the refrigerator The purpose of the present invention is to provide a control device for a refrigerator-freezer that can perform fine temperature control by calculating.

[0013]

According to the present invention, there is provided a refrigerator-freezer control apparatus according to the present invention, comprising: a refrigerator having a refrigerator compartment for chilling and storing food.
A refrigerating compartment door switch that operates by opening and closing the refrigerating compartment door, a door opening and closing detecting device that detects opening and closing of the refrigerating compartment door from the operation of the refrigerating compartment door switch, and a timer counter built-in. Door opening time calculation means for calculating a door opening time by an output signal, an outside air temperature sensor provided outside the refrigerator, and an outside air temperature detection means for detecting the outside air temperature outside the refrigerator by the outside air temperature sensor, A refrigerating compartment temperature sensor provided in the refrigerating compartment; an in-compartment temperature detecting means for detecting an in-compartment temperature in the refrigerating compartment by the refrigerating compartment temperature sensor; a door opening time calculated by the door opening time calculating means; An atmosphere for calculating an ambient temperature change degree of the refrigerator compartment from the outside air temperature detected by the temperature detecting means and the inside temperature detected by the inside temperature detecting means. Means for calculating the air temperature, differentiating means for determining the rate of change of the internal temperature based on the output of the internal temperature detecting means, and the internal temperature detected by the internal temperature detecting means and the internal quantity determined by the differentiating means. A heat load calculating means for calculating a heat load of the food in the refrigerator compartment (food temperature × heat capacity) from the rate of change of the internal temperature, and further calculating a heat load fluctuation (increase / decrease of the heat load); A memory for storing a control rule based on an empirical rule for obtaining a rotational speed and an opening degree of the damper; and a heat load amount calculated by the heat load calculating means, a heat load change calculated by the heat load calculating means, and a calculation by the atmosphere temperature calculating means. A fuzzy inference program for performing a fuzzy logic operation based on the calculated degree of change in the ambient temperature of the refrigerator compartment and the control rules retrieved from the memory to calculate the rotation speed of the fan motor and the opening of the damper. A fan motor control means for controlling the fan motor based on a rotation speed of the fan motor and an opening degree of the damper calculated by the fuzzy inference processor; and a damper control means for controlling the damper.

[0014]

According to the present invention, the load amount and the load fluctuation calculated by the heat load (hereinafter referred to as load) calculating means, the degree of change in the ambient temperature of the refrigerator compartment calculated by the calculating means of the ambient temperature, and the memory having the above structure are provided. Based on the control rules extracted from the above, a fuzzy logic operation is performed by a fuzzy inference processor, and the rotation speed of the fan motor and the opening of the damper are obtained. Therefore, the fan is driven by controlling the fan motor based on the rotation speed obtained as described above, and the damper is controlled based on the opening degree obtained as described above. be able to.

[0015]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a control device for a refrigerator according to an embodiment of the present invention.

FIG. 1 is a block diagram of a control device of a refrigerator according to an embodiment of the present invention. FIG. 2A is a graph showing a membership function of a fuzzy variable with respect to a load in the embodiment of the present invention. ) Is a graph showing the membership function of the fuzzy variable with respect to the load change in the embodiment of the present invention, FIG. 2C is a graph showing the membership function of the fuzzy variable with respect to the degree of change in the ambient temperature in the embodiment of the present invention, and FIG. FIG. 4 is a flowchart for explaining the operation in the embodiment of the present invention, FIG. 4 is a graph showing the relationship between the door opening and closing time and the ambient temperature in the embodiment of the present invention, and FIG. 5 shows the procedure of fuzzy inference in the embodiment of the present invention. It is a flowchart for explaining.

In FIG. 1, reference numeral 24 denotes an outside air temperature detecting means, which detects an outside air temperature outside the refrigerator by an outside air temperature sensor 38. Reference numeral 25 denotes a door opening time calculating unit which calculates a door opening time based on a signal output from the door opening / closing detecting unit 21. Numeral 26 denotes an atmospheric temperature calculating means. The door opening time calculated by the door opening time calculating means 25, the outside air temperature detected by the outside air temperature detecting means 24, and the inside temperature detected by the inside temperature detecting means 22. The degree of change in the ambient temperature of the refrigerator is calculated from the temperature.

Reference numeral 27 denotes a differentiating means for differentiating the output from the internal temperature detecting means 22 to obtain a change rate of the internal temperature.
Numeral 28 is a load calculating means. The load amount of the food in the freezer compartment (food temperature × heat capacity) is calculated based on the internal temperature detected by the internal temperature detecting means 22 and the rate of change of the internal temperature obtained by the differentiating means 27. ) Is calculated, and the load variation (increase / decrease of the load amount) is further calculated. Reference numeral 29 denotes a memory which stores a control rule based on an empirical rule for obtaining the rotation speed of the fan motor 35 and the opening of the damper 37.

Numeral 30 denotes a fuzzy inference processor. The load amount and the load variation calculated by the load calculating means 28, the degree of change in the ambient temperature of the refrigerator compartment calculated by the atmospheric temperature calculating means 26, and the memory 30 are retrieved. A fuzzy logic operation is performed based on the set control rules, and the rotation speed of the fan motor 35 and the opening of the damper 37 are calculated. Based on these results, the fan motor control means 34 controls the fan motor 35 having a variable rotational speed, and the damper control means 3
In step 6, the variable opening damper 37 is controlled.

The operation of the refrigerator-freezer control device configured as described above will be described below with reference to FIGS.

First, the door opening / closing detecting means 21 determines whether or not the door 6 of the refrigerator compartment 9 is closed based on the operation of the refrigerator compartment door switch 18 (Step 1). If the door 6 is closed, the outside air temperature is determined. The detecting means 24 detects the outside air temperature Tout outside the refrigerator by the outside air temperature sensor 38 (S
Step 2), the refrigerator temperature detecting means 22 detects the refrigerator temperature Tpc ₀ in the refrigerator compartment by the refrigerator compartment temperature sensor 19 (St).
ep3).

When the door 6 is opened, the door opening time calculating means 25 starts a timer counter in the door opening time calculating means 25 in order to calculate the door opening time based on the signal from the door opening / closing detecting means 21. (Step
4) Stop the fan 35 and the compressor 17 (St)
ep5). At this time, foods are taken in and out of the refrigerator compartment 9, and outside air flows into the compartment (Step 6).

Next, when the door 6 is closed (Step
7) The door opening time calculation means 25 stops the timer counter (Step 8), and calculates the door opening time H from this timer counter (Step 9). Then, the atmospheric temperature calculating means 26 calculates the door opening time H calculated by the door opening time calculating means 25 and the outside air temperature detecting means 24.
Is calculated from the outside air temperature Tout detected by the above and the inside temperature Tpc ₀ detected by the inside temperature detecting means 22 (Step 10). Here, as the door opening time increases, the ambient temperature of the food in the refrigerator increases, and the relationship between the door opening time and the ambient temperature is a characteristic curve as shown in FIG. Is obtained, and the degree of change in ambient temperature D is

[0024]

(Equation 1)

[0025] Further, the refrigerator temperature detecting means 22 detects the refrigerator temperature Tpc in the refrigerator room by the refrigerator temperature sensor 19 (Step 11), and the differentiating means 27 outputs the output from the refrigerator temperature detecting means 22 as shown in (Equation 2). Is differentiated, and the rate of change △ Tpc of the internal temperature is obtained (Step
12).

[0026]

(Equation 2)

Then, the load calculating means 28 calculates the load of the food in the refrigerator based on the internal temperature Tpc detected by the internal temperature detecting means 22 and the rate of change ΔTpc of the internal temperature determined by the differentiating means 27. The amount W is calculated (Step 13), and the load variation V is calculated as shown in (Equation 3) (St
ep14).

[0028]

(Equation 3)

Next, the calculated load W and load variation V
The ambient temperature change degree D is input to the fuzzy inference processor 30 (Step 15). The fuzzy inference processor 30 takes out the control rules stored in the memory 29 in advance and calculates the rotation speed m of the fan motor by fuzzy inference. Similarly, the opening degree n of the damper is calculated (Step 16). The fan motor control means 34 drives the fan 14 by controlling the fan motor 35 based on the rotation speed m of the fan motor, and the damper control means 36 controls the damper 37 based on the opening degree n of the damper. (Step 18).

Here, fuzzy inference for obtaining the rotation speed of the fan motor and the opening degree of the damper for optimally controlling the temperature of the refrigerator compartment is executed based on the following control rules.

The control rules employed in this embodiment are the following 27 rules. For example, rule 1: if the load amount is large, the load fluctuation is positive, and the degree of change in the ambient temperature is large,
Increase the rotation speed of the fan motor and increase the opening of the damper.

Rule 2: If the load is medium, the load fluctuation is zero, and the degree of change in the ambient temperature is medium, the rotation speed of the fan motor is set to be medium and the opening of the damper is set to be medium.

Rule 3: If the load is small, the load variation is positive, and the degree of change in the ambient temperature is small, the rotation speed of the fan motor is reduced and the opening of the damper is reduced. ... Rule 27: If the load is small, the load fluctuation is negative and the degree of change in the ambient temperature is small, the fan motor is turned off and the damper is closed. It is.

This is because if the load amount is large or the degree of change in the ambient temperature is large, it is necessary to send a lot of cool air to cool down, the opening degree of the damper must be increased, and the rotation of the fan motor must be accelerated. This is a rule obtained from experience.

Therefore, the language rule is a control rule for the rotational speed of the fan motor and the opening of the damper, which can be optimally controlled in the temperature of the refrigerating compartment, obtained by the inventor from a number of experimental data. (Table 1) shows the relationship between the load amount, the load fluctuation, and the degree of change in the ambient temperature.

[0036]

[Table 1]

(Table 1) is a table showing the relationship between the control rules. The load W is determined in three stages in the horizontal direction (LW = many, MW = medium,
SW = small), load fluctuation V in three stages (IV = positive, NV =
Zero, DV = negative), the degree of change in ambient temperature D in the vertical direction is divided into three stages (LD = large, MD = medium, SD = small), and the load amount W and load variation V are classified as described above. At the intersection of the ambient temperature change D and the load amount W, the load fluctuation V, and the optimal fan motor rotation speed and damper opening corresponding to the ambient temperature change D are arranged.

The above language rules are stored in the memory 29 of FIG.
Is stored according to the following rules. The number of control rules adopted in this embodiment is 27.

Rule 1: IF Wis LW and Vis IV and Dis LD LD THEN Mis H Nis H Rule 2: IF Wis MW and Vis NV and Dis MD MD THEN Mis M Nis M Rule 3: IF Wis SW and Vis IV and Dis SD SD THEN Miss L Nis L Rule 27: IF Wis SW and Vis DV and Dis SD THEN Miss OFF Nis OFF Rule 1 above. 2... The rule of rule 27 determines the load amount W, the load variation V, the ambient temperature change D, the rotational speed M of the fan motor, and the opening N of the damper stepwise as shown in (Table 1). Therefore, when performing fine control, the load amount W, the load fluctuation V, and the ambient temperature In the measured load amount w, load change v, and ambient temperature change degree d, the antecedent part (IF
), It is necessary to calculate the degree of satisfying the above-mentioned part, and to estimate the rotational speed m of the fan motor and the opening degree n of the damper according to the degree. For this reason, in the present embodiment, the above-described degree is determined by the load amount W, the load fluctuation V,
Is calculated using a fuzzy variable membership function for.

FIG. 2A shows the membership function μSW of the fuzzy variables SW, MW, and LW with respect to the load W.
2 (w), μMW (w) and μLW (w). FIG. 2 (b) shows the fuzzy variable D with respect to the load variation V.
V, NV, IV membership functions μDV (v), μN
FIG. 2 shows V (v) and μIV (v).
(C) is a fuzzy variable S for the ambient temperature change D.
D, MD, LD membership function μSD (d), μM
D (d) and μLD (d). The fuzzy inference executed by the fuzzy inference processor 30 includes the control rule 1, the rule 2,..., The rule 27 and FIG.
A fuzzy logic operation is performed using the membership functions (b) and (c) to calculate the frequency.

The fuzzy inference procedure of Step 16 and Step 17 of FIG. 3 will be described below with reference to the flowchart of FIG.

[0042] In Step 19, load w ₀ by fuzzy reasoning processor 30, by using the membership function of the fuzzy variables to the load variation v ₀ and ambient temperature gradient d _0, load w _0, a load fluctuation v ₀ and ambient temperature Degree of change d ₀
Of the membership value (represented by the M value in the figure) at the time.

In Step 20, the obtained load amount w ₀ ,
The degree to which the membership value of the fuzzy variable with respect to the load variation v ₀ and the degree of change in the ambient temperature d ₀ satisfies the antecedents of each of the 27 rules is calculated by the synthesis method as follows.

In the figure, the fuzzy variable for the load amount is indicated by A, the fuzzy variable for the load change is indicated by B, and the fuzzy variable for the ambient temperature change is indicated by C.

Rule 1: h1 = μLW (w ₀ ) ∩IV (v ₀ ) ∩LD (d ₀ ) = MIN ｛μLW (w ₀ ), μIV (v ₀ ), μLD (d ₀ )｝ --- ( 1) Rule 2: h2 = μMW (w ₀ ) ∩μNV (v ₀ ) ∩μMD (d ₀ ) = MIN ｛μMW (w ₀ ), μNV (v ₀ ), μMD (d ₀ )｝ --- (2 Rule 3: h3 = μSW (w ₀ ) ∩μIV (v ₀ ) ∩μSD (d ₀ ) = MIN {μSW (w ₀ ), μIV (v ₀ ), μSD (d ₀ )} --- (3) Rule 27: h27 = μSW (w ₀ ) ∩μDV (v ₀ ) ∩μSD (d ₀ ) = MIN ｛μSW (w ₀ ), μDV (v ₀ ), μSD (d ₀ )｝ --- ( 27) (1), the w ₀ enters the region LW for loading W, and the v ₀ enters the region IV to the load variation V, and the d ₀ is Kiri囲Proposition that enters an area LD for temperature gradient D is the ratio of w ₀ enters the LW, v ₀ is the rate and d ₀ entering the IV established at a rate of as smaller value of the ratio entering the LD, i.e. rules The antecedent part of 1 indicates that it is established at the rate of h1. Similarly, in the case of Rule 2, Rule 3,..., Rule 27, which are Expressions (2), (3),..., (27), the antecedents are the ratios of h2, h3,. It is expressed that it holds.

In Step 20, the fan motor frequency and the opening degree of the damper at the load amount w ₀ , the load fluctuation v ₀ and the ambient temperature change degree d ₀ are obtained by the membership function of the execution part of the control rule as follows. . The fan motor frequency m ₀ and the damper opening n ₀ are calculated using the maximum height method, which is one of the single point methods, of the ratios h1, h2,. Maximum height h within
The value of the consequent part of the control rule having i is calculated as follows.

M ₀ = M (max {h1, h2,..., H27}) n ₀ = F (max {h1, h2,..., H27}) Thus, the frequency m ₀ of the fan motor and the damper opening n ₀ of is obtained.

Therefore, in this embodiment, since the load amount, the load fluctuation, and the degree of change in the ambient temperature are used as the control parameters, fine control can be performed. Also,
Since the control rules are based on human empirical rules, it is possible to control the temperature of the refrigerating compartment with the optimal rotation speed of the fan motor and the opening of the damper.

[0049]

As described above, the present invention relates to a refrigerator-freezer equipped with a refrigerator compartment capable of refrigerated and storing food, wherein the refrigerator compartment door switch which operates by opening and closing the refrigerator compartment door, and the refrigerator compartment door are provided. Door opening / closing detection means for detecting the opening / closing of the door of the refrigerator compartment from the operation of the switch, a door counter built-in, and a door opening time calculation means for calculating a door opening time by a signal output from the door opening / closing detection means; An outside air temperature sensor provided outside the refrigerator, an outside air temperature detecting means for detecting the outside air temperature outside the freezer refrigerator by the outside air temperature sensor, a refrigerator room temperature sensor provided inside the refrigerator compartment, and refrigeration by the refrigerator room temperature sensor. An internal temperature detecting means for detecting an indoor internal temperature, and a door opening time calculated by the door opening time calculating means and detected by the outside air temperature detecting means. Calculating means for calculating the degree of change in the ambient temperature of the refrigerator from the measured outside air temperature and the internal temperature detected by the internal temperature detecting means; and the internal temperature of the refrigerator based on the output of the internal temperature detecting means. A heat load (food temperature × heat capacity) of the food in the refrigerator compartment from the differentiating means for obtaining the rate of change, and the internal temperature detected by the internal temperature detecting means and the change rate of the internal temperature obtained by the differentiating means. ), And further, a heat load calculating means for calculating a heat load fluctuation (increase / decrease in heat load amount), a variable opening damper and a variable speed fan motor provided in the refrigerator compartment for feeding cool air, A memory that stores a control rule based on an empirical rule for obtaining the opening degree of the damper and the number of revolutions of the fan motor, and a heat load amount calculated by the heat load calculation unit,
A fuzzy logic operation is performed on the basis of the degree of change in the ambient temperature of the refrigerator compartment calculated by the means for calculating the thermal load and the ambient temperature and the control rules retrieved from the memory, and the opening degree of the damper and the rotational speed of the fan motor , A damper control means for controlling the degree of opening of the damper calculated by the fuzzy inference processor, and a fan motor control means for controlling the fan motor, so that the refrigerated food in the refrigerator compartment can be kept fresh. It is possible to obtain an optimal operation amount based on an empirical rule that can be well stored for a long period of time, and it is possible to finely control the temperature of the refrigerator compartment. For example, when a large amount of food is packed in summer when the outside air temperature is high, rapid cooling can be performed by the rotation speed of the fan motor and the opening of the damper according to the load of the food.
In addition, since the temperature is controlled by the operation amount according to the load of the food, unnecessary energy is not consumed.

[Brief description of the drawings]

FIG. 1 is a block diagram of a control device of a refrigerator according to an embodiment of the present invention.

2A is a graph showing a membership function of a fuzzy variable with respect to a load in the embodiment; FIG. 2B is a graph showing a membership function of a fuzzy variable with respect to a load change in the embodiment; Graph showing membership function of fuzzy variables with respect to ambient temperature change in example

FIG. 3 is a flowchart for explaining the operation in the embodiment;

FIG. 4 is a graph showing a relationship between a door opening / closing time and an ambient temperature in the embodiment.

FIG. 5 is a flowchart for explaining a procedure of fuzzy inference in the embodiment.

FIG. 6 is a block diagram of a conventional refrigerator-freezer control device.

FIG. 7 is a flowchart for explaining an operation in a conventional example.

[Explanation of symbols]

 9 Refrigerating Room 18 Refrigerating Room Door Switch 19 Refrigerating Room Temperature Sensor 21 Door Open / Close Detecting Means 22 Inside Temperature Detecting Means 24 Outside Air Temperature Detecting Means 25 Door Opening Time Calculating Means 26 Atmospheric Temperature Calculation Means 27 Differentiating Means 28 Load Calculation Means 29 Memory 30 Fuzzy inference processor 34 Fan motor control means 35 Fan motor 36 Damper control means 37 Damper 38 Outside air temperature sensor

Continuation of the front page (51) Int.Cl. ⁷ identification code FI G05D 23/00 G05B 19/05 J (58) Investigated field (Int.Cl. ⁷ , DB name) F25D 11/02 F25D 17/06 312 F25D 17/08 306 G05B 13/02 G05B 19/05 G05D 23/00

Claims (1)

(57) [Claims] 1. A refrigerating refrigerator provided with a refrigerating compartment capable of refrigerating and storing foods, a refrigerating compartment door switch which operates by opening and closing a door of the refrigerating compartment, and a door opening and closing detecting opening and closing of the refrigerating compartment door switch. A door opening time calculating means incorporating a detecting means, a timer counter, and calculating a door opening time based on a signal output from the door opening / closing detecting means; an outside air temperature sensor provided outside the refrigerator; and the outside air temperature sensor Outside air temperature detecting means for detecting the outside air temperature outside the refrigerator, refrigerator internal temperature detecting means for detecting the temperature of the refrigerator compartment provided in the refrigerator compartment, the door opening time calculated by the door opening time calculation means, The degree of change in the ambient temperature of the refrigerator compartment is calculated from the outside air temperature detected by the outside air temperature detecting means and the inside temperature detected by the inside temperature detecting means. Calculating means for calculating an ambient temperature, a differentiating means for calculating a rate of change of the internal temperature based on an output of the internal temperature detecting means, and an internal temperature detected by the internal temperature detecting means and calculated by the differentiating means. A heat load calculating means for calculating the heat load of the food in the refrigerator compartment (food temperature × heat capacity) from the rate of change of the temperature in the refrigerator, and further calculating the heat load fluctuation (increase / decrease of the heat load), and sending in cool air. A variable opening damper and a variable speed fan motor provided in the refrigerator compartment, a memory storing a control rule based on an empirical rule for determining the opening degree of the damper and the rotation speed of the fan motor, and Heat load calculated by the calculating means,
A fuzzy logic operation is performed on the basis of the degree of change in the ambient temperature of the refrigerator compartment calculated by the calculating means for the thermal load fluctuation and the ambient temperature and the control rule extracted from the memory, and the opening degree of the damper and the fan motor. A fuzzy inference processor for calculating the frequency, damper control means for controlling the opening of the damper based on the opening of the damper and the rotation speed of the fan motor calculated by the fuzzy inference processor, and controlling the rotation speed of the fan motor. A controller for a refrigerator-freezer comprising a fan motor control means.