JP2998848B2 - Refrigerator refrigerator control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention is based on an empirical rule based on an empirical rule for minimizing the temperature rise in a refrigerator during defrosting in a defrosting control of a refrigerator-freezer (hereinafter abbreviated as a refrigerator) and eliminating an influence on foods. The present invention relates to a refrigerator-freezer control device which infers an optimal precool time and a defrost time based on a control rule obtained and a membership function of fuzzy variables constituting the rule, and outputs the result.

[0002]

2. Description of the Related Art A refrigerator-freezer control device controls a fan motor, a compressor, and an electric damper so as to control the temperature of a freezing room, a refrigerator room, and a vegetable room of a refrigerator at a set temperature. . Furthermore, by applying electricity to the defrost heater, the frost attached to the evaporator is removed.
For example, Japanese Patent Publication No. 2-53707, Japanese Patent Publication No. 2-631
No. 53 discloses this.

[0003] Hereinafter, a control device for a conventional refrigerator-freezer will be described with reference to the drawings, in particular, defrost control of an evaporator.

FIG. 5 is a block diagram of a conventional refrigerator-freezer control device. In FIG. 5, reference numeral 1 denotes a refrigerator main body, which is composed of an outer box 2, an inner box 3, and a urethane foam insulating material 4 formed in a gap between the two, and three doors 5, 6, and 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 freezer compartment door switch that operates by opening and closing the door 5 of the freezer compartment 8, 19 denotes a freezer compartment temperature sensor, and 20 denotes an outside air temperature sensor. 21 is fan 1
4 for driving the fan motor. Reference numeral 22 denotes a defrost heater for removing frost attached to the evaporator 13.

Reference numeral 26 denotes an outside air temperature detecting means for detecting the outside air temperature outside the refrigerator by the outside air temperature sensor 20,
27 is a compressor operating time integrating means for integrating the operating time of the compressor after the completion of the defrosting. 36
Is a defrost control means for judging the start of defrost control based on the outside air temperature detected by the outside air temperature detection means 26 and the integrated operation time of the compressor integrated by the compressor operation time integration means 27.

[0007] 33 controls the fan motor 21 and controls the fan 1
4 is a fan motor control means for driving the compressor 4, 34 is a compressor control means for driving the compressor 17,
Reference numeral 35 denotes a defrost heater control unit that controls the energization of the defrost heater 22.

[0008] The operation of the control device for a refrigerator-freezer constructed as described above will be described below with reference to Figs. FIG. 6 is a flowchart for explaining the conventional defrosting control of the evaporator 13.

First, the outside air temperature detecting means 26 detects the outside air temperature Tout outside the refrigerator (Step 20), and the compressor operating time integrating means 27 operates the compressor which is the operating time of the compressor since the previous defrosting was completed. The integration time X is integrated (Step 21). And
The defrost control means 36 determines the start of the defrost control from the outside air temperature Tout and the accumulated operating time X of the compressor (S
step22). Here, (Table 1) shows an example of the relationship between the outside air temperature Tout and the accumulated operating time X of the compressor when the conventional defrost control is started.

[0010]

[Table 1]

When it is determined that defrosting has started, the fan motor control means 33 controls the temperature rise in the refrigerator during defrosting.
Controls the fan motor 21 to drive the fan 14, and the compressor control means 34 drives the compressor 17 to perform pre-cooling (pre-cooling) for a certain time (Step 23). Next, when the precooling is completed, the defrost heater control means 35 supplies power to the defrost heater 22 to start defrost (Step 24). Then, when the completion of the defrosting is detected by the bimetal thermostat or the like, the defrosting heater control means 35 stops the energization to the defrosting heater 22, and ends the defrosting (Step 25).

[0012]

However, in the above-described configuration, the start of defrosting is determined as shown in (Table 1).
In this case, the defrosting end was performed only by detecting the end of the defrosting by using a bimetal thermostat or the like. Therefore, fine defrosting control could not be performed. Heat load, etc.), there was a problem that foods could be adversely affected by overcooling or insufficient cooling.

The present invention solves the above problems,
Heat load of food in the freezer compartment (hereinafter abbreviated as load),
By calculating the amount of frost adhering to the evaporator and the operation amount according to the door opening / closing frequency (frequency of using the refrigerator),
An object of the present invention is to provide a control device for a refrigerator-freezer that can perform fine defrosting control.

[0014]

According to the present invention, there is provided a refrigerator-freezer control apparatus according to the present invention, wherein a freezer is provided in a freezer compartment for freezing or chilling and storing food. A temperature sensor, an internal temperature detecting means for detecting an internal temperature in the freezer compartment by the freezer temperature sensor, a differentiating means for obtaining a change rate of the internal temperature by an output of the internal temperature detecting means, Heat load calculating means for calculating the heat load amount of food in the freezer compartment (food temperature × heat capacity) from the inside temperature detected by the temperature detecting means and the rate of change of the inside temperature determined by the differentiating means;
An outside air temperature sensor provided outside the refrigerator, an outside air temperature detecting means for detecting the outside air temperature outside the refrigerator using the outside air temperature sensor, and a compressor operation time integration for integrating the operation time of the compressor after defrosting is completed. Means for calculating the amount of frost formed on the evaporator from the outside air temperature detected by the outside air temperature detection means and the cumulative operation time of the compressor integrated by the compressor operation time integration means. A computing unit, a freezer compartment door switch that operates by opening and closing the freezer compartment door, a door open / close detector that detects opening and closing of the freezer compartment door from the operation of the freezer compartment door switch, and an output from the door open / close detector. Door open / close frequency calculating means that calculates the door open / close frequency based on the signal to be used, and empirical rules for determining the precool time and the defrost time. A memory for storing control rules,
The heat load amount calculated by the heat load calculation means, the frost amount calculated by the frost formation amount calculation means, the door opening / closing frequency calculated by the door opening / closing frequency calculation means, and the memory A fuzzy inference processor that performs a fuzzy logic operation to calculate a precool time and a defrost time based on the extracted control rules, and a fan that controls a fan motor based on the precool time and the defrost time calculated by the fuzzy inference processor The motor control means includes a motor control means, a compressor control means for driving the compressor, and a defrost heater control means for controlling energization of the defrost heater.

[0015]

According to the present invention, the load amount calculated by the heat load calculating means, the frost amount of the evaporator calculated by the frost amount calculating means, and the door opening / closing frequency calculating means are calculated. A fuzzy logic operation is performed by the fuzzy inference processor based on the door opening / closing frequency and the control rules retrieved from the memory, and a precool time and a defrost time are obtained. Therefore, based on the operation amount obtained as described above, the fan is controlled by controlling the fan motor, the pre-cool is performed by driving the compressor, and the defrost is performed by energizing the defrost heater. Defrost control can be performed.

[0016]

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 for a refrigerator-freezer 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 amount of frost in the embodiment of the present invention. FIG. 2C is a graph showing the membership function of the fuzzy variable with respect to the frequency of opening and closing the door in the embodiment of the present invention. FIG. 4 is a flowchart for explaining the operation in the embodiment of the present invention, and FIG. 4 is a flowchart for explaining the procedure of fuzzy inference in the embodiment of the present invention.

In FIG. 1, reference numeral 23 denotes a refrigerator temperature detecting means for detecting the refrigerator temperature in the freezer compartment. Numeral 24 denotes a differentiating means for differentiating the output from the internal temperature detecting means 23 to obtain a change rate of the internal temperature. Numeral 25 is a heat load calculating means. The load amount of food in the freezer compartment (food temperature x Heat capacity). Numeral 28 is a calculation unit for calculating the amount of frost. The frost formation on the evaporator 13 is calculated based on the outside air temperature detected by the outside air temperature detection unit 26 and the integrated operation time of the compressor integrated by the compressor operation time integration unit 27. Calculate the amount of frost. Reference numeral 29 denotes a door opening / closing detecting unit which detects opening / closing of the door 5 of the freezing room 8 based on the operation of the freezing room door switch 18.
Numeral 30 denotes a door opening / closing frequency calculating means, which calculates the door opening / closing frequency based on a signal output from the door opening / closing detecting means 29. Reference numeral 31 denotes a memory which stores a control rule based on an empirical rule for obtaining a precool time and a defrost time.

Reference numeral 32 denotes a fuzzy inference processor, which is a load calculated by the heat load calculating means 28, a frost amount of frost adhering to the evaporator 13 calculated by the frost amount calculating means 28, and a door. Based on the door opening / closing frequency calculated by the opening / closing frequency calculating means 30 and the control rule fetched from the memory 31, fuzzy logic operation is performed to calculate the precool time and the defrost time.

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

First, the door opening / closing detecting means 29 determines whether or not the door 5 of the freezer compartment 8 is closed based on the operation of the freezer compartment door switch 18 (Step 1). The compressor 17 is stopped (Step 2). At this time, food is put in and taken out of the freezing room 8 (Step 3). Next, when the door 5 is closed (Step 4), the refrigerator temperature detecting means 23 detects the refrigerator temperature Tfc in the freezer compartment by the freezer compartment temperature sensor 19 (Step 5), and the differentiating means 24 becomes as shown in (Equation 1). Then, the output from the internal temperature detecting means 23 is differentiated to determine the internal temperature change rate ΔTfc (Step 6).

[0022]

(Equation 1)

Then, the heat load calculating means 25 calculates the load W of the food in the freezer compartment from the temperature Tfc in the refrigerator and the rate of change ΔTfc in the temperature in the refrigerator (Step 7).

Next, the outside air temperature detecting means 26 detects the outside air temperature Tout outside the refrigerator by the outside air temperature sensor 20 (Step 8), and the compressor operating time integrating means 27 operates the compressor for the operating time since the previous defrosting was completed. (St)
ep9). The calculation means 28 for calculating the amount of frost calculates the outside air temperature T
out and the accumulated operating time X of the compressor, the evaporator 13
The frost formation amount U of the frost adhering to is calculated (Step 10).

Further, the door opening / closing frequency calculating means 30 calculates the door opening / closing frequency D based on the signal output from the door opening / closing detecting means 29 (Step 11).

The calculated load W, frost formation U and door opening / closing frequency D are input to the fuzzy inference processor 32 (Step 12). Fuzzy inference processor 32
Then, the control rule stored in the memory 31 is taken out in advance, and the precool time pt and the defrost time dt are calculated by fuzzy inference (Step 13). Here, the frost formation amount U of the frost adhering to the evaporator 13 and the door In particular, when the door opening / closing frequency D is low, it is determined whether to start the defrosting control based on the opening / closing frequency D (Step 14). And
If the defrost control is started, the fan motor control means 3
Numeral 3 drives the fan 14 by controlling the fan motor 21, and the compressor control means 34 drives the compressor 17 to perform precooling based on the precooling time pt (Step 15).

Next, when the precooling is completed, the defrost heater control means 35 energizes the defrost heater 22 and defrosts the frost adhering to the evaporator based on the defrost time dt (S
step16).

Here, the fuzzy inference for obtaining the pre-cool time and the defrost time for performing the optimal defrost control of the evaporator is executed based on the following control rules.

First, the following nine control rules are employed in this embodiment to determine the precool time. For example, Rule 1: If the load is large and the amount of frost is large, increase the precool time. Rule 2: If the load is normal and the amount of frost is normal, set the precool time to normal. Rule 3: If the load is small and the amount of frost is small,
Shorten the pre-cool time.

And so on.

This is because if the load increases, it takes time to lower the internal temperature and the precooling time must be lengthened, and if the amount of frost increases, it takes time to perform defrosting. It is a rule obtained from experience that the pre-cooling time must be lengthened because it is necessary to lower the storage temperature. Therefore, the above language rule is a control rule for a precooling time in which the inventor can perform a precooling in the optimal defrosting control of the evaporator, obtained from a number of experimental data, and defines the relationship between the load amount and the amount of frost formation. (Table 2).

[0032]

[Table 2]

(Table 2) is a table showing the relationship between the control rules. The load W is set in three stages in the horizontal direction (LW = many, MW = medium,
SW = small), and the amount of frost U in the vertical direction is divided into three stages (LU =
(Multi, MU = medium, SU = small), and at the position where the divided load amount W and frost amount U intersect, the optimum position corresponding to the load amount W and frost amount U Three pre-cooling times (LPT = long, MPT = medium, SPT =
Short).

The above language rules are stored in the memory 31 of FIG.
Is stored according to the following rule. The number of control rules employed in this embodiment is nine. Rule 1: IF Wis LW and UIs LU THEN PTis LPT Rule 2: IF Wis MW and UIs MU THEN PTis MPT Rule 3: IF Wis SW and Uis SU THEN PT is SPT ... Rule 1, Rule 2,..., Rule 9 determine the load amount W, the frost amount U, and the precool time PT stepwise as shown in (Table 2), so that fine control is performed. Calculates the degree to which the antecedent part (IF part) of the control rule is satisfied with the actually measured load amount w and frost formation amount u in the middle of each stage of the load amount W and the frost formation amount U. And the pre-cool time pt according to the degree
Needs to be estimated. Therefore, in the present embodiment, the degree is calculated using a membership function of a fuzzy variable with respect to the load amount W and the frost formation amount U.

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. 2B shows the fuzzy variable S for the frost formation amount U.
Membership functions μSU (u), μM of U, MU, LU
U (u) and μLU (u). The fuzzy inference executed by the fuzzy inference processor 32 includes the control rule 1, rule 2,..., Rule 9 and FIG.
A fuzzy logic operation is performed using the membership function of (b) to calculate the manipulated variable.

Hereinafter, the procedure of fuzzy inference which is Step 13 of FIG. 3 will be described with reference to the flowchart of FIG.

[0037] In Step 17, by using the membership function of fuzzy variable by the fuzzy inference processor 32 for loading w ₀ and frost quantity u _0, membership value in the load weight w ₀ and frost quantity u ₀ (in the drawing (Displayed as M value).

In Step 18, the degree to which the membership value of the fuzzy variable with respect to the obtained load w ₀ and frost formation u ₀ satisfies the antecedent of each of the nine rules is as follows. It is calculated by the synthesis method.

In the figure, the fuzzy variable for the load amount is indicated by A, and the fuzzy variable for the frost amount is indicated by B. Rule 1: h1 = μLW (w ₀ ) ∩μLU (u ₀ ) = MIN ｛μLW (w ₀ ), μLU (u ₀ )｝ --- (1) Rule 2: h2 = μMW (w ₀ ) ∩μMU ( u ₀ ) = MIN {μMW (w ₀ ), μMU (u ₀ )} --- (2) Rule 3: h3 = μSW (w ₀ ) ∩μSU (u ₀ ) = MIN ｛μSW (w ₀ ), μSU (U ₀ )｝ −−− (3) Equation (1) indicates that the proposition that the w ₀ falls in the area LW for the load W and the u ₀ falls in the area LU for the frost formation U are , W ₀ is in the LW and u ₀ is in the LU as a smaller value, that is, the antecedent of Rule 1 is established at the rate of h1. Similarly, in the case of rules 2 and 3, which are formulas (2) and (3), it indicates that the antecedent is established at the ratio of h2 and h3, respectively.

In Step 19, the pre-cool time at the load w ₀ and the frost formation u ₀ is obtained by the membership function of the execution part of the control rule as follows. The precool time pt ₀ is calculated using the height method, which is one of the single point methods, by using the ratios h1 and h
Calculated as shown in (Equation 2) as the value of the weighted average of h9.

[0041]

(Equation 2)

Thus, the precool time pt ₀ is obtained. Therefore, in this embodiment, since the load amount and the frost amount are used as the control parameters, fine control is possible. In addition, since the control rules are based on human empirical rules, precooling in the defrosting control of the evaporator can be performed in an optimal precooling time.

Next, the following nine control rules are employed in this embodiment to determine the defrosting time. For example, Rule 1: If the frequency of door opening and closing is low and the amount of frost is large, extend the defrosting time. Rule 2: If the door opening / closing frequency is normal and the amount of frost is normal, set the defrost time to normal. Rule 3: If the frequency of door opening and closing is high and the amount of frost is small, shorten the defrosting time.

And so on.

This is because if the amount of frost increases, it takes time to perform defrosting, and the defrosting time must be lengthened. If the frequency of opening and closing the door increases, the frequency of use of the refrigerator increases. This is a rule obtained from the experience that if the energization of the defrost heater is performed for a long time, the food may be adversely affected. Therefore, the language rule is a control rule for the defrosting time that can be performed in the defrosting control of the optimal evaporator, which is obtained from a number of experimental data by the inventor. The relationship is as shown in (Table 3).

[0046]

[Table 3]

Here, the method of calculating the defrost time by fuzzy inference is the same procedure as the method of calculating the precool time described above, and a description thereof will be omitted.

[0048]

As described above, the present invention relates to a refrigerator which can freeze or refrigerate food and store it.
A freezer compartment temperature sensor provided in the freezer compartment, an internal compartment temperature detecting means for detecting the internal compartment temperature in the freezer compartment by the freezer compartment temperature sensor, and a change rate of the internal compartment temperature by an output of the internal compartment temperature detecting means. A heat load (food temperature × heat capacity) of food in the freezer compartment is calculated from the differentiating means to be obtained, and the internal temperature detected by the internal temperature detecting means and the rate of change of the internal temperature obtained by the differentiating means. Means for calculating a heat load to be performed, an outside air temperature sensor provided outside the refrigerator, an outside air temperature detecting means for detecting the outside air temperature outside the refrigerator by the outside air temperature sensor, and operation of the compressor after defrosting is completed. A compressor operating time integrating means for integrating time, an outside air temperature detected by the outside air temperature detecting means, and a compressor operating time integrated by the compressor operating time integrating means. Means for calculating the amount of frost adhering to the evaporator from the rolling integration time, a freezing compartment door switch that operates by opening and closing the freezing compartment door, and freezing from the operation of the freezing compartment door switch. Door opening / closing detecting means for detecting opening / closing of a door of a room, door opening / closing frequency calculating means for calculating a door opening / closing frequency based on a signal output from the door opening / closing detecting means, and an empirical rule for obtaining a precool time and a defrost time. A memory that stores a control rule based on, the heat load amount calculated by the heat load calculation unit, and the frost amount calculated by the frost formation amount calculation unit,
A fuzzy inference processor for performing a fuzzy logic operation to calculate a pre-cool time and a defrost time based on the door opening / closing frequency calculated by the door opening / closing frequency calculating means and the control rule fetched from the memory; Based on the pre-cool time and the defrost time calculated by the above, by providing a fan motor control means for controlling the fan motor, a compressor control means for driving the compressor, and a defrost heater control means for controlling the energization of the defrost heater, In defrosting control, it is possible to minimize the rise in the internal temperature during defrosting, to obtain an optimal operation amount based on an empirical rule that can eliminate the influence on food, and to finely control the defrosting of the evaporator. . For example, when pre-cooling is performed, overcooling or insufficient cooling is prevented, and the food is not adversely affected.
Further, since the door opening / closing frequency is calculated and defrosting control is started at a time when the refrigerator is not frequently used, defrosting is performed in accordance with the amount of frost formed on the evaporator, so that optimal defrosting control can be performed.

[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 the amount of frost in the embodiment; 7 is a graph showing a membership function of a fuzzy variable with respect to a door opening / closing time in the embodiment.

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

FIG. 4 is a flowchart for explaining a procedure of fuzzy inference in the embodiment.

FIG. 5 is a block diagram of a conventional refrigerator-freezer control device.

FIG. 6 is a flowchart for explaining an operation in a conventional example.

[Explanation of symbols]

 18 Freezer compartment door switch 19 Freezer compartment temperature sensor 20 Outside air temperature sensor 23 Internal temperature detecting means 24 Differentiating means 25 Heat load calculating means 26 Outside air temperature detecting means 27 Compressor operating time integrating means 28 Defrosting amount calculating means 29 Door opening and closing Detecting means 30 Calculation means for door opening frequency 31 Memory 32 Fuzzy inference processor 33 Compressor control means 34 Fan motor control means 35 Defrost heater control means

────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI G05D 23/00 G05D 23/00 G (56) References JP-A-4-139372 (JP, A) JP-A-4-124574 ( JP, A) JP-A-4-169768 (JP, A) JP-A-4-263771 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F25D 11/00-13/00 F25D 21/06-21/08 F25D 29/00 G05B 13/02 G05D 23/00

Claims (1)

(57) [Claims] 1. A freezing refrigerator capable of freezing or chilling and storing foods, wherein a freezing room temperature sensor provided in the freezing room and an inside temperature of the freezing room detected by the freezing room temperature sensor. Temperature detecting means, differentiating means for obtaining a change rate of the internal temperature based on the output of the internal temperature detecting means, internal temperature detected by the internal temperature detecting means, and internal temperature obtained by the differentiating means. Heat load of food in the freezer compartment (food temperature x heat capacity)
Calculating the heat load, an outside air temperature sensor provided outside the refrigerator, an outside air temperature detection means for detecting the outside air temperature outside the refrigerator by the outside air temperature sensor, and a compressor after defrosting is completed. Means for accumulating the operating time of the compressor, the outside air temperature detected by the outside air temperature detecting means, and the accumulated operating time of the compressor integrated by the compressor operating time integrating means, A means for calculating the amount of frost to calculate the amount of frost, a freezer compartment door switch that operates by opening and closing the door of the freezer compartment, and a door opening and closing detecting means for detecting the opening and closing of the door of the freezer compartment from the operation of the freezer compartment door switch A door opening / closing frequency calculating means for calculating a door opening / closing frequency based on a signal output from the door opening / closing detecting means; A memory that stores a control rule based on an empirical rule for determining the interval, a heat load amount calculated by the heat load calculation unit, a frost formation amount calculated by the frost formation calculation unit, and the door A fuzzy inference processor that performs fuzzy logic operation to calculate pre-cool time and defrost time based on the door opening / closing frequency calculated by the opening / closing frequency calculation means and the control rule retrieved from the memory, and a calculation by the fuzzy inference processor. A fan motor control unit that controls a fan motor, a compressor control unit that drives a compressor, and a defrost heater control unit that controls energization of a defrost heater based on the pre-cool time and the defrost time that have been set. Control device for refrigerator-freezer.