JPH102660A - Refrigerator defrost control device - Google Patents

Abstract

(57) [Summary] The present invention aims to perform defrosting at an optimal timing before exceeding the limit frost formation amount even when the start of defrosting by detection of frost formation is abnormal. A timer means (20) for measuring the actual time of the cooling operation and a detection output of a frost detection means (11) for detecting the frost formation of the cooler when the actual time of the cooling operation reaches a predetermined cooling time. And defrost control means 17 for starting the defrosting operation and correcting the predetermined cooling time to an optimum value based on the actual times of the latest cooling operations for the past several times.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a defrost control device for a refrigerator.

[0002]

2. Description of the Related Art As a conventional refrigerator defrost control device,
For example, the defrosting is performed again when a predetermined time or more has elapsed from the time when the previous defrosting of the cooler has been completed, or when the accumulated operation time of the compressor has been longer than a predetermined time since the time when the defrosting has been completed. There is. In the defrost control method of this device, the defrost cycle is fixed, and therefore, the time during which defrost is not performed, that is, the setting of the cooling time is performed, for example, in a refrigerator in order to maintain the cooling performance and suppress the generation of residual ice. For example, when a large amount of food with a large amount of water evaporation is stored, it is necessary to set the conditions under severer conditions than usual.

[0003]

Conventionally, the defrost cycle is
For example, in the case of storing a large amount of food with a large amount of water evaporation in the refrigerator, the conditions were set under severer conditions than usual. However, there is a problem that the defrosting is performed, the frequency of energizing the defrost heater increases, and the power consumption increases. In order to solve this problem, for example, there is a demand defrosting method in which a temperature sensor is mounted in a cooler, the amount of frost is detected by a change in the detected temperature, and defrosting is performed according to the amount of frost. It is considered. In this demand defrosting method, useless defrosting is not performed, and appropriate defrosting control can be expected. However, this demand defrosting method still has the following problems. That is, if the manner of frost on the cooler is the same each time, one temperature sensor is mounted on the place where frost is most likely to occur, and when the detected temperature reaches a certain temperature, defrosting is started. In practice, however, the following factors cause that the frost does not always become the same every time, and also depends on individual differences. As a result, between the fins far from the mounting position of the temperature sensor, Clogging may start to occur. Therefore, depending on how frost forms, the change in the detected temperature of the temperature sensor in the cooler is not always the same every time, and in some cases, defrosting may be started with the amount of frost considerably exceeding the allowable value. Ice could have formed.

[0004] Next, factors causing a change in the above-mentioned frost formation will be described. In a refrigerator such as a mid-freezer type comprising a refrigerator compartment, a freezer compartment, and a vegetable compartment from above, there are two left and right flow paths for return air from the freezer to the cooler. If there is a bias in the way of insertion, there will be a difference between the left and right intake air volumes. For example, when the air flow is deviated to the right, in the cooler, the difference between the air volume of the right freezer compartment return air and the air volume of the refrigerator compartment / vegetable compartment return air to the cooler center becomes large. If the balance of the air volume of the left and right freezer compartment return air in the freezer / vegetable compartment partition is lost, the pressure difference (static pressure) between the refrigerator compartment / vegetable compartment return air and the freezer compartment return air increases,
The right freezer compartment return air with the largest air volume enters the flow path of the central refrigerator compartment / vegetable compartment return air with the least air volume. As a result, the flow path of the return air in the refrigerator compartment / vegetable compartment shifts to the left and the way of frosting shifts to the left, causing a change in the pattern of frost formation and an unusual temperature change in the temperature detected by the temperature sensor. A pattern occurs. As a result, the temperature detected by the temperature sensor at the time of the limit frost formation amount differs depending on the pattern of frost formation. In this case, if a plurality of temperature sensors are attached to the cooler and the temperature is detected, it is expected that defrosting can be started with high accuracy, but the cost increases, and if all of the temperature sensors break down, the problem is solved. No. For this reason, there has been a major problem how to accurately detect the amount of frost by simply adding one temperature sensor. In addition, when the temperature sensor is out of order, there is a problem that the defrost may not be performed forever.

[0005] The present invention has been made in view of the above,
Even if the start of defrosting due to frost detection is abnormal, it is possible to perform defrosting at the optimal timing according to the user's usage conditions, etc., before exceeding the limit frost formation amount, and the generation of residual ice due to excessive frost formation An object of the present invention is to provide a defrost control device for a refrigerator that can be suppressed.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the invention according to the first aspect of the present invention is directed to a refrigerator for removing defrost based on a detection result of frost detection means for detecting frost formation of a cooler. In the frost control device, timer means for measuring the actual time of the cooling operation from the end of each defrost until the start of the next defrost,
It is determined whether or not the actual time of the cooling operation measured by the timer means has reached a predetermined cooling time. When the actual time of the cooling operation has reached the predetermined cooling time, the detection output of the frost detection means is determined. Defrost control means for starting defrosting independently of the actual time of the cooling operation measured this time and the actual time of the cooling operation measured up to the previous time and correcting the predetermined cooling time to an optimal value by the actual time. The gist is to have. With this configuration, by adding a protection function of performing forced defrosting when the cooling operation time reaches a predetermined cooling time, defrosting start by frosting detection can be started at a normal set frosting amount depending on a user's use condition and the like. Even if you are uncertain,
Defrosting can be reliably started. Further, by correcting the predetermined cooling time set value based on the latest cooling operation times of the past several times, the optimum predetermined cooling time is automatically set in accordance with the use situation of the user.

According to a second aspect of the present invention, in the refrigerator defrosting control device according to the first aspect, the defrosting control means detects the actual time of the cooling operation for the latest several past times and the detection of the frost formation. In the storage means, the number of times defrosting has been started and the number of times defrosting has been performed when the actual time of the cooling operation has reached the predetermined cooling time are stored in the storage means, and the number of times that defrosting has been detected by the detection of the frost formation is stored. Is larger than a predetermined number of times, the predetermined cooling time is updated by the maximum value among the actual cooling operation times in which the defrosting is detected by the detection of the frosting, and the actual time of the cooling operation reaches the predetermined cooling time. When the number of times of defrosting is larger than a predetermined number, the predetermined cooling time is updated by one step longer. According to this configuration, the correction of the predetermined cooling time is, specifically, the latest defrost start determination condition for the past several times, that is, whether the defrost starts by detecting frost formation or the defrost starts by ending the real time of the cooling operation. The determination is made based on the determination conditions and the cooling operation time. As a result, a more optimal predetermined cooling time is automatically set in accordance with the use situation of the user.

According to a third aspect of the present invention, in the refrigerator defrosting control device according to the first aspect, there is provided a timer means for measuring a required time for defrosting, and the defrosting control means measures the time by the timer means. When the required defrosting time is longer than the predetermined defrosting time, the gist is configured to update the predetermined cooling time by one step shorter. With this configuration, when an abnormality is detected that is longer than the predetermined defrost time, the predetermined cooling time is corrected by one step, for example, one hour, so that the frost detection status exceeds the set frost amount. Even when the determined situation continues, the predetermined cooling time according to the situation is automatically set. This prevents the defrosting time from being abnormally long and affecting the food in the refrigerator.

According to a fourth aspect of the present invention, in the defrost control device for a refrigerator according to the first aspect, the frost formation detecting means detects an air temperature on a flow path of return air from a refrigerator in the cooler. The gist of the present invention is that it is an air temperature sensor in the cooler for detecting. With this configuration, as the cooling time elapses, frost forms on the return air from the refrigerating compartment in the cooler, and the air volume decreases to lower the temperature. By using an air temperature sensor in the cooler that detects the temperature of this portion as the frost detection means, the frost formation of the cooler is accurately detected.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. The defrost control device for a refrigerator according to the present embodiment performs demand control of starting frost formation by detecting frost formation by a temperature sensor mounted in the cooler. A timer for measuring the actual cooling operation time is provided, and a protection function for forcibly starting defrosting when the measured actual time reaches a set predetermined value (predetermined cooling time) is provided. The actual time of the cooling operation until the start of the frost is measured, and the average value of the measured values is corrected for each defrost cycle so that the above-mentioned predetermined value becomes an optimum value. First, referring to FIGS. 2 and 3,
A description will be given of the configuration around the refrigerator and its cooler (evaporator). As shown in FIG. 2, the refrigerator is a mid-freezer type and is roughly divided into four compartments, and includes a refrigerator compartment 1, a first freezer compartment 2a, a second freezer compartment 2b, and a vegetable compartment 3 from above. . Hereinafter, the first freezing room 2a, the second freezing room 2
This is referred to as the freezing room 2 including b. Reference numerals 4 and 5 denote a compressor (compressor) and a cooler (evaporator) in the refrigerating cycle, 6 a fan for circulating the cool air cooled by the cooler 5 into the refrigerator, and 7 a cool air to the refrigerator compartment 1 and the vegetable compartment 3. It is a motor damper that controls the flow. Cooling in the refrigerator is performed by circulating cool air in the refrigerator by a fan 6, and its flow path is separately configured in a refrigerator room 1, a vegetable room 3 and a freezer room 2, and returns to the cooler 5. I have. Reference numeral 8 denotes a freezer compartment temperature sensor for detecting the temperature in the freezer compartment 2, and reference numeral 9 denotes a refrigerator compartment temperature sensor for detecting the temperature in the refrigerator compartment 1. When the value detected by the freezer compartment temperature sensor 8 reaches a predetermined set value, the refrigeration cycle operates, and the fan 6 also rotates in conjunction with this. In addition, refrigerator compartment temperature sensor 9
The opening / closing of the motor damper 7 is controlled by the detected value of.

FIG. 3 shows the vicinity of the cooler 5. The return air of the refrigerator compartment 1 / vegetable compartment 3 flows in the center of the cooler 5, and the return air of the freezer compartment 2 flows on the left and right sides thereof, and the return air of the refrigerator compartment 1 / vegetable compartment 3 flows. At a substantially central portion of the portion, one air temperature sensor 11 inside the cooler serving as frost formation detecting means is attached. The air temperature sensor 11 in the cooler is attached by being thermally insulated from the cooler 5 by the sensor fixture 13, and the return air from the refrigerator compartment 1 and the vegetable compartment 3 flowing through the cooler 5 is provided. The temperature is detected. At the upper left of the cooler 5, a defrost return temperature sensor 12 for detecting the temperature of the cooler 5 itself is attached. During defrost, the detected value of the defrost return temperature sensor 12 becomes a predetermined temperature. In this case, the power supply to the defrost heater is terminated.

Next, the configuration of the defrost control device will be described with reference to the block diagram of FIG. The freezer compartment temperature sensor 8 and the refrigerator compartment temperature sensor 9 are connected to the comp / damper control unit 14. The comp / damper control unit 14 sends a control signal to the motor damper drive unit 15 and the compressor drive unit 16 based on the detected values of the freezer compartment temperature sensor 8 and the refrigerator compartment temperature sensor 9 to turn on / off the compressor 4 and the motor damper 7.
OFF is controlled, and an open / close signal of the motor damper 7 is sent to a defrost control unit 17 as defrost control means. The defrost control unit 17 is connected to the cooler air temperature sensor 11 and the defrost return temperature sensor 12. The defrost control unit 17 is provided with a first timer 18, a second timer 19, and a third timer 20, each of which serves as timer means, and further serves as storage means for storing the actual time of a cooling operation described later. Memory 21 is provided. The comp / damper control unit 14, the defrost control unit 17, the first, second, and third timers 18, 19, 20 and the memory 21 are the microcomputer 2
3. When an open signal of the motor damper 7 is sent from the comp / damper control unit 14 to the defrost control unit 17, that is, when the cooling of the refrigerator compartment 1 and the vegetable compartment 3 is started, the first timer 18 measures a certain time. The defrost controller 17 inputs the temperature detected by the cooler air temperature sensor 11 after the elapse of the predetermined time until the next time the motor damper 7 is closed. As shown in FIG. 4, the measured value of the above-mentioned fixed time by the first timer 18 indicates the transient response of the refrigeration cycle and the heat followability of the air temperature sensor 11 in the cooler after the compressor ON / motor damper is opened. The temperature is set in consideration of the refrigeration cycle and the temperature of the air temperature sensor 11 in the cooler reaches a stable (equilibrium state) state, so that the temperature detected by the air temperature sensor 11 in the cooler can be input. When the temperature detected by the air temperature sensor 11 in the cooler falls below a predetermined value set in advance, the defrost heater driving unit 22
To start defrosting. Third timer 2
0 is a timer for measuring the actual time of the cooling operation, which is reset at the end of each defrost and starts counting. Then, when the count value reaches the set predetermined cooling time, the defrost control unit 17 performs the defrost heater driving unit 22 regardless of the temperature detected by the air temperature sensor 11 in the cooler.
To start the defrosting operation and wait the real-time count value of the third timer 20.
1 stores the actual time count value. The method of storing data in the memory 21 is to overwrite the oldest data with the latest data in order to store the latest real-time data for the past several times. Second
Is a timer for measuring the time required for defrosting.

FIG. 5 shows a change in temperature of the cooler internal temperature (the temperature detected by the cooler internal air temperature sensor 11) when frost formation has progressed. In this data, the operation time from the start of the test is plotted on the horizontal axis, and the detected temperature for each ON / OFF cycle of the motor damper 7 is plotted. With time, frost progresses in the central portion of the cooler (air return portion from the refrigerator compartment / vegetable compartment), the amount of air applied to the air temperature sensor 11 in the cooler decreases, and the detected temperature decreases. At the same temperature as the cooler temperature. The above-mentioned predetermined value is set to, for example, −25 ° C., and the defrosting is started until the defrost amount reaches the limit.

Next, the first control method will be described with reference to the flowchart of FIG. The default setting at power-on is
The defrost control unit 17 sets the initial value of the actual cooling operation time experimentally determined in advance in the third timer 20 and starts the third timer 20. The initial setting real time is set to, for example, an average time (48 hours) in a general use state in summer (step 101). During the cooling operation, the defrost control unit 17 determines whether the temperature detected by the air temperature sensor 11 in the cooler has dropped below a predetermined value, ie, whether frost has formed, during the frost detection section (step 102). (Step 1
03). If frost formation is not detected based on the detected temperature of the cooler air temperature sensor 11, the cooling operation is continued (step 104), and the actual time count value of the third timer 20 exceeds the set predetermined cooling time. It is determined whether or not it has been performed (step 105). If the predetermined cooling time has not elapsed (No in Step 105), the process returns to the frost formation detection determination based on the temperature detected by the air temperature sensor 11 in the cooler. Then, when frost formation is detected based on the detected temperature in the cooler or when it is determined that the actual cooling operation time has exceeded the predetermined cooling time (Yes in step 103, Yes in 105), the actual time counted by the third timer 20 is used. The time data is read out and stored in the memory 21, and whether the start of defrosting is determined by the detection of frost formation or the start of defrosting at the end of real time is determined by the memory 21.
(Step 106), the compressor 4 and the fan 6 are stopped, and a drive signal is sent to the defrost heater drive unit 22 to start defrost (Step 107). Then, when the end of the defrosting is determined (Ye in step 108)
s) The latest seven real-time data stored in the memory 21 is read out (step 109). If the number of times of defrosting detected by frost formation detection is, for example, 6 or more (Yes in step 110), the MAX time is selected from the actual cooling operation time data of defrosting detected by frost formation detection and the predetermined cooling is performed. If the number of times of defrosting in real time is half or more (Step 111), the time set value is set (Step 111).
s) The predetermined cooling time set value is extended by a unit time, for example, one hour, from the previous set value (step 113).
Then, from the next real time determination, the real time is determined using the selected predetermined cooling time set value. When the air temperature sensor 11 inside the cooler fails, the MIN time can be stored and its value can be set.

As described above, according to the present control method, the demand defrost control is provided with a protection function of performing forced defrost when the actual cooling operation time exceeds a set predetermined cooling time. Even if frost formation at the start of defrosting cannot be accurately detected with the normal set frost amount depending on the user's usage condition, or if frost formation cannot be detected due to a failure of the air temperature sensor 11 in the cooler, etc., it is surely removed. Since the frost can be started and the predetermined cooling time set value is corrected by the latest past several times of the defrost start determination conditions and the cooling operation time until the start of the defrost, the predetermined cooling time set value is changed according to the user's usage condition. The optimal time can be automatically set according to the time, so even if the defrost start by frost detection is abnormal, an appropriate defrost time can be determined,
The generation of residual ice due to excessive frost can be prevented.

Referring to the flowchart of FIG. 7 and FIG.
The second control method will be described. This control method determines the time required for defrosting with respect to the first control method, and determines whether the required time for defrosting exceeds a predetermined defrosting time set in advance.
The predetermined cooling time set value is varied. FIG.
The flowchart of (A)-of the flowchart of FIG.
Only the replacement part between (B) is shown. When the frost formation is detected based on the detected temperature in the cooler or when it is determined that the actual cooling operation time exceeds the predetermined cooling time, the n-th defrost start determination condition and the actual cooling operation time measurement data are stored (step 201) and start defrosting (step 2)
02), the second timer 19 for measuring the required time for defrosting is started (step 203). When the end of the defrosting is determined (Yes in step 204), the defrosting time count value of the second timer 19 is compared with a predetermined defrosting time set in advance (step 205). The predetermined defrosting time is determined by previously obtaining a defrosting time corresponding to the set amount of frosting for frosting detection. That is, as shown in FIG. 8, the amount of frost and the defrost time are in a proportional relationship, and this relationship is experimentally determined to determine the predetermined defrost time. Here, the detected frost amount is set to 450 cc, which is the limit frost amount, and the 48-minute defrost time at that time is set to the predetermined defrost time. As a result of the comparison, when the defrost time count value of the second timer 19 is longer than the predetermined defrost time (when an abnormality is detected) (Yes in step 205), this determination result is stored in the memory 21 as the n-th determination result. Then, the predetermined cooling time set value is reduced by a unit time, for example, one hour from the previous set value (step 206) (step 20).
7). On the other hand, if the defrosting time count value of the second timer 19 is smaller than the predetermined defrosting time (in a normal state) (step 2).
(No. 05), the n-th determination result is stored in the memory 21 (step 208), and the latest seven real-time data stored in the memory 21 is read out (step 209). If the frost required time determination is OK (Yes in step 210), as in the first control method, if the number of times of defrosting detection is six or more, for example (Yes in step 211), The MAX time is selected from the actual cooling operation time data that has entered the defrosting by the frost detection (step 212), and is set as a predetermined cooling time setting value (step 213). If it is half or more (Yes in step 214), the predetermined cooling time set value is extended by a unit time, for example, one hour, from the previous set value (step 215). On the other hand, if the determination of the required defrosting time is NG at least once in all the times (No in step 210), the process returns to the cooling operation without updating the predetermined cooling time set value.

As described above, according to the present control method, it is determined whether the previous frost formation detection state and the protection predetermined cooling time set value are good or not based on the required defrosting time. When a larger abnormality is detected, the predetermined cooling time set value is set to be shorter than the previous set value, so that even when the situation where the frost detection situation is determined to exceed the set frost amount continues, the Predetermined cooling time can be set according to the situation, unnecessarily long defrost does not affect the food in the refrigerator, and the generation of residual ice due to excessive frost can be prevented, and appropriate timing according to any situation Can start defrosting.

[0018]

As described above, according to the first aspect of the present invention, there is provided a defrosting control device for a refrigerator that performs defrosting based on the detection result of frosting detection means for detecting frosting of a cooler. Timer means for measuring the actual time of the cooling operation from the end of each defrost to the start of the next defrost, and whether or not the actual time of the cooling operation measured by the timer means has reached a predetermined cooling time When the actual time of the cooling operation has reached the predetermined cooling time, defrosting is started irrespective of the detection output of the frost detection means and the actual time of the cooling operation measured this time and the previous time Defrost control means that corrects the predetermined cooling time to be an optimum value based on the actual time of the cooling operation measured up to, so that when the cooling operation time reaches the predetermined cooling time, forced defrosting is performed. To provide additional protection By correcting the constant cooling time set value based on the latest cooling operation times of the past several times, even if the defrost start due to frost detection is abnormal, defrost can be started at a reliable and optimal timing. Generation of residual ice due to excessive frost can be suppressed.

According to the second aspect of the present invention, the defrosting control means includes the latest real time of the cooling operation for the past several times,
The number of times defrosting is detected by the detection of the frost and the number of times defrosting is started when the actual time of the cooling operation reaches the predetermined cooling time are stored in the storage means, and the number of times the defrosting is detected is detected. If the number of times of frost is greater than a predetermined number, the predetermined cooling time is updated by the maximum value of the actual times of the cooling operation in which defrosting is started upon detection of the frosting, and the actual time of the cooling operation is reduced to the predetermined time. When the number of times of defrosting due to reaching the time is larger than a predetermined number, the predetermined cooling time is configured to be updated by one step longer, so that the correction of the predetermined cooling time is specifically performed for the latest several times in the past. The defrosting start determination condition, that is, the defrosting start by the frost detection or the defrosting start by the real time end of the cooling operation is performed by the determination condition and the cooling operation time,
It is possible to automatically set a more optimal predetermined cooling time according to the use situation of the user and the like.

According to the third aspect of the present invention, there is provided a timer means for measuring a required time for defrosting, wherein the defrosting control means comprises:
When the required time for defrosting measured by the timer means is longer than a predetermined defrosting time, the predetermined cooling time is updated by one step shorter, so that the required time for defrosting is longer than the predetermined defrosting time and an abnormality is detected. When the predetermined cooling time is corrected by one step shorter, the predetermined cooling time is automatically set in accordance with the situation even if the situation where the frost detection status is judged to exceed the set frost amount continues. can do. Therefore, the defrosting time is not abnormally long and does not affect the food in the refrigerator, and the defrosting can be started at an appropriate timing according to any situation, and the generation of residual ice due to excessive frosting can be prevented. Can be suppressed.

According to the fourth aspect of the present invention, the frost detection means is an air temperature sensor in a cooler for detecting an air temperature on a flow path of return air from a refrigerator in the cooler. It is possible to easily and reliably detect frost formation on the vessel, and to accurately start defrosting by frost formation detection.

[Brief description of the drawings]

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

FIG. 2 is a sectional view showing an internal configuration of the refrigerator applied to the embodiment.

FIG. 3 is a diagram showing a configuration around a cooler in the refrigerator.

FIG. 4 is a diagram for explaining an input timing of temperature information to a defrost control unit in the embodiment.

FIG. 5 is a diagram showing an example of a change in the detection temperature of an air temperature sensor in a cooler when frost formation advances in the embodiment.

FIG. 6 is a control flowchart for explaining a first control method in the embodiment.

FIG. 7 is a control flowchart for explaining a second control method in the embodiment.

FIG. 8 is a diagram showing a relationship between the amount of frost and the required time for defrosting in the embodiment.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 refrigeration room 5 cooler 11 cooler air temperature sensor serving as frost detection means 17 defrost control unit (defrost control means) 19 second timer (timer means) for measuring required defrost time 20 cooling operation Third timer for measuring real time (timer means) 21 Memory (storage means)

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Atsushi Kusunoki 8 in Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture Inside the Toshiba Living Space Systems Research Institute (72) Inventor Tsuneji Tsukuni 3-chome, Shimbashi, Minato-ku, Tokyo No. 3-9 Toshiba Abu E Co., Ltd. (72) Inventor Hiroaki Asakura 3-3-9 Shimbashi, Minato-ku, Tokyo Toshiba Abu E Co., Ltd.

Claims (4)

[Claims] In a defrosting control device for a refrigerator that performs defrosting based on a detection result of a frosting detection unit that detects frosting of a cooler, from the end of each defrosting to the next start of defrosting. Timer means for measuring the actual time of the cooling operation, and determining whether or not the actual time of the cooling operation measured by the timer means has reached a predetermined cooling time, wherein the actual time of the cooling operation is the predetermined cooling time. When it reaches, the defrosting is started independently of the detection output of the frost detection means and the predetermined cooling time is determined by the actual time of the cooling operation measured this time and the actual time of the cooling operation measured up to the previous time. A defrost control device for a refrigerator, comprising: a defrost control unit that corrects to an optimum value. 2. The defrosting control means reaches a predetermined cooling time for the actual time of the cooling operation for the latest several past times, the number of times the defrosting is started by detecting the frost formation, and the actual time of the cooling operation. The number of times that defrosting has been performed is stored in the storage means, and if the number of times that defrosting has been detected in the detection of the frosting is greater than a predetermined number, the cooling operation in which defrosting has been detected in the detection of the frosting. The predetermined cooling time is updated by the maximum value of the real time, and when the actual time of the cooling operation reaches the predetermined cooling time and the number of defrosting operations is larger than the predetermined number, the predetermined cooling time is decremented. 2. The defrosting control device for a refrigerator according to claim 1, wherein the controller is configured to update the length of the stage. 3. A timer means for measuring a required time for defrosting, wherein the defrosting control means controls the predetermined cooling time when the required time for defrosting measured by the timer means is longer than a predetermined time for defrosting. The refrigerator defrosting control device according to claim 1, wherein the device is configured to be updated one step shorter. 4. The air conditioner according to claim 1, wherein the frost detection means is an air temperature sensor in the cooler for detecting an air temperature on a flow path of return air from the refrigerator in the cooler. Refrigerator defrost control device.