KR102662390B1 - Refrigerator automatic control system - Google Patents

Abstract

The present invention is an automatic control system for a refrigerator. To describe it in more detail, it aims to provide a more efficient control system by analyzing the state of the refrigerant and controlling the refrigerator more accurately and sensitively. , in a refrigerator including a condenser, a compressor control unit configured in the refrigerator to control the compressor according to the suction pressure of the compressor, an outdoor unit fan control unit configured in the refrigerator to control the outdoor unit fan according to the discharge pressure of the compressor, and a temperature control unit configured to control the compressor. It is characterized in that it includes at least one of a compressor cooling control unit configured in the refrigerator and a regulation control unit configured in the refrigerator to regulate the suction pressure of the compressor. By this invention, freezing, refrigeration, and air conditioning states are achieved and abnormal states are achieved. This is an invention that can expect a number of effects, such as increasing the efficiency of the refrigerator and extending its lifespan, by detecting and controlling it in advance.

Description

Refrigerator automatic control system {Refrigerator automatic control system}

The present invention is a refrigerator automatic control system, which, to be described in more detail, is intended to control the operation of the refrigerator or each device that makes up the refrigerator.

Various methods are being developed to control refrigerators.

For example, as published in Republic of Korea Patent No. 0416685 (announced on April 28, 2004), a regenerator, condenser, evaporator, and absorber are connected by piping to form a circulation path for refrigerant and absorbent liquid, and the heating amount of the regenerator is loaded. In the control method of an absorption refrigerator controlled according to the above, the temperature of the regenerator is detected, the heating amount of the regenerator is limited for a first predetermined time from when the temperature of the regenerator reaches a predetermined temperature, and the heating amount of the regenerator is limited at the elapse of the first predetermined time. When the temperature of the regenerator is lower than the predetermined temperature, the heating amount of the regenerator is controlled according to the load, and when the temperature of the regenerator reaches the predetermined temperature within a second predetermined time after the elapse of the first predetermined time, the operation of the regenerator is stopped to maintain a stopped state. A control method for an absorption refrigerator characterized in that it continues is known.

Other technologies include a compressor that compresses refrigerant gas, a drive motor that drives the compressor, and a device that controls the number of rotations of the drive motor, as published in Korean Patent No. 0459091 (announced on December 3, 2004). A control device for a refrigerator equipped with an inverter, comprising: a suction pressure detection means of the compressor, an overload detection means of the inverter, and a control unit that receives signals from the detection means and outputs a predetermined power switching control signal. It includes a power switching means that switches the power to the driving motor according to a control signal from the control unit, and a vibration measuring means including a vibration detection unit, a vibration meter, and a recorder. A refrigerator control system that generates a first power conversion signal to be supplied to the compressor, and transmits a rotation frequency control signal to the inverter so that the inverter provides a rotation frequency that changes continuously or in steps to the drive motor of the compressor. The device is announced.

Another technology, as published in Korean Patent Publication No. 2017 No. 0076253 (published on July 4, 2017), includes operating a refrigerator to store cold air in the coolant, measuring the temperature of the coolant, Determining whether the temperature is below a preset first set temperature; If the temperature of the coolant is below the first set temperature, measuring the outside air temperature and obtaining a first set time corresponding to the outside temperature. , measuring the operating time of the refrigerator and determining whether the time exceeds the first set time, and if the operating time of the refrigerator exceeds the first set time, operating the refrigerator. A refrigerator control method has been disclosed that includes the step of stopping, wherein the first set time is preset so that the higher the outside temperature is, the longer it becomes.

KR 10-0416685 B1 (2004.04.28.) KR 10-0459091 B1 (2004.12.03.) KR 10-2017-0076253 A (2017.07.04.)

In the present invention, a new technology was created to solve the problems of the prior art described above. Existing refrigerators or air conditioners control the operation of the refrigerator by measuring only the temperature and humidity of the room where the evaporator is installed, making agile and sensitive control impossible. In contrast, the purpose of the present invention is to provide a more efficient refrigerator automatic control system by controlling the cooler more accurately and sensitively by analyzing the states of the refrigerant flowing in and the refrigerant being discharged from the compressor.

In addition, although not separately described, other purposes within the scope that can be inferred considering the specific details and claims for carrying out the invention below are also included in the overall subject of the present invention.

In the present invention, as a specific means for solving the problems of the above invention, in constructing an automatic refrigerator control system, in a refrigerator including an evaporator, compressor, and condenser, a compressor control unit configured in the refrigerator to control the compressor according to the suction pressure of the compressor and, an outdoor fan control unit configured in the refrigerator to control the outdoor fan according to the discharge pressure of the compressor, a compressor cooling control section configured in the refrigerator to control the temperature of the compressor, and a regulation control section configured in the refrigerator to control the suction pressure of the compressor. It is characterized by including the above.

The compressor control unit includes a suction pressure sensor configured in the refrigerant suction line to measure the pressure of the refrigerant suction line between the evaporator and the compressor, and a first conversion portion configured to convert the pressure value measured from the suction pressure sensor into a digital signal. , It may be characterized by including an arithmetic unit configured to determine whether the digital signal transmitted from the conversion unit is a value within a preset range, and a first switch configured to turn the compressor on/off in conjunction with the arithmetic unit.

The outdoor unit fan control unit includes a discharge pressure sensor configured in the refrigerant discharge line to measure the pressure of the refrigerant discharge line between the compressor and the condenser, and an outdoor unit configured to receive the pressure value measured from the discharge pressure sensor and control the rotation speed of the outdoor unit fan. It may be characterized as including a fan shifting device.

A second conversion unit configured to convert the pressure value measured from the discharge pressure sensor into a digital signal, a calculation unit configured to determine whether the digital signal transmitted from the conversion unit is within a preset range, and a calculation unit linked to the calculation unit to turn on the outdoor fan. It may further include a second switch configured to control /off operation.

The compressor cooling control unit includes a discharge temperature sensor configured in the refrigerant discharge line to measure the temperature of the refrigerant discharge line between the compressor and the condenser, and a third conversion unit configured to convert the temperature value measured from the discharge temperature sensor into a digital signal. , characterized in that it includes an arithmetic unit configured to determine whether the digital signal transmitted from the third conversion unit is a value within a preset range, and a third switch configured to control the on/off operation of the injection valve installed in the compressor in conjunction with the arithmetic unit. can do.

The compressor control unit includes a suction pressure sensor configured in the refrigerant suction line to measure the pressure in the refrigerant suction line between the evaporator and the compressor, and a discharge pressure sensor configured in the refrigerant discharge line to measure the pressure in the refrigerant discharge line between the compressor and the condenser. A sensor, a first conversion unit and a second conversion unit configured to convert each pressure value measured from the suction pressure sensor and the discharge pressure sensor into a digital signal, and a digital signal transmitted from the first conversion unit and the second conversion unit. It may be characterized by including a calculation unit configured to determine whether the value is within a preset range, and a first switch configured to control the on/off operation of the compressor in conjunction with the calculation unit.

The regulation control unit includes a regulation line configured to communicate with the refrigerant suction line between the evaporator and the compressor and the refrigerant discharge line between the compressor and the condenser, and a suction configured in the refrigerant suction line to measure the pressure of the refrigerant suction line between the evaporator and the compressor. A pressure sensor, a first conversion unit configured to convert the value measured from the suction pressure sensor into a digital signal, a calculation unit configured to determine whether the digital signal transmitted from the first conversion unit is a value within a preset range, and an output value of the calculation unit. A triac configured to receive the pulse wave signal and generate a pulse wave signal, and a PWM valve that opens and closes according to the pulse wave signal received by the triac to prevent the low pressure side pressure from dropping excessively by spraying the discharge gas into the suction pipe through the regulation line. It may be characterized as being included.

When the refrigerator stops operating, the interlock unit configured to turn off the PWM valve by an interlocked relay may be further included.

According to the specific means for solving the above-mentioned problem, it is possible to detect in advance whether the target freezing, refrigeration, or air conditioning state is achieved or an abnormal state occurs before measuring the temperature of the evaporator, thereby preventing unnecessary operation of the refrigerator. By eliminating energy waste, unnecessary power consumption and maintenance costs can be prevented.

Additionally, by preventing excessive operation of the refrigerator, the lifespan of the refrigerator and its components can be extended and the probability of malfunction can be greatly reduced.

It is an invention with many expected effects, such as being able to control the compressor suction pressure without causing any risks to the equipment, such as failure of sliding part lubrication.

1 is a configuration diagram of a refrigerator to which an example of the present invention is applied.
Figure 2 is a main circuit diagram to which the compressor control unit of the present invention is applied.
Figure 3 is a flowchart showing the operation of the compressor control unit of the present invention
Figure 4 is a main circuit diagram to which the outdoor fan control unit of the present invention is applied.
Figure 5 is a flowchart showing the operation of the outdoor fan control unit of the present invention
Figure 6 is a main circuit diagram to which the compressor cooling control unit of the present invention is applied.
Figure 7 is a flowchart showing the operation of the compressor cooling control unit of the present invention
Figure 8 is a flow chart of the main parts to which the refrigerator control unit of the present invention is applied.
Figure 9 is a circuit diagram showing the operation of the regulation control unit of the present invention.
Figure 10 is a main circuit diagram to which the regulation control unit of the present invention is applied.
Figure 11 is a circuit diagram of the automatic control system of the present invention

The present invention seeks to provide an automatic control system for a refrigerator, and will be described in more detail with the drawings below. The attached drawings are only examples to easily explain the content and scope of the technical idea of the present invention and are limited thereto. This does not mean that the terms used are only for explaining the embodiment in detail and should not be construed as being limited to the terms in question.

The refrigerator automatic control system 1 of the present invention described above is applied to the refrigerator 100 (including refrigerators and air conditioners) including the evaporator 101, compressor 102, and condenser 103 as shown in FIG. It is an automatic control system (1) for automatically controlling the refrigerator 100 or each device of the refrigerator 100 according to the measured value of the sensor installed in the refrigerator 100.

The freezer 100 is operated by the load side (sales showcase for food display, freezer room, freezer, refrigerator, cooling dehumidifier, water chiller, industrial and commercial air conditioner, ice maker, etc.) for a predetermined purpose, that is, when a set temperature or humidity is reached or the product When freezing is completed, the freezer 100 no longer needs to be operated, so it is automatically stopped by the automatic controller, and then automatically restarted when the variable (temperature, humidity, or associated pressure) falls outside a set range. do.

For equipment that is subject to refrigeration or whose load fluctuates significantly due to the surrounding environment and purpose of use, the freezer (100) will need to be turned on or off frequently, and for equipment that has small load fluctuations, the time interval between turns on of the freezer (100) will be small. It will be long.

In the present invention, various control systems that control each device are configured in detail, and will be explained sequentially and step by step with drawings.

As the first automatic control system 1, the compressor control unit 2 as shown in FIGS. 2 and 3 will be described.

During the refrigerant circulation process of the refrigerator 100, when the low-temperature, low-pressure gaseous refrigerant flows from the evaporator 101 to the compressor 102, the measured state of the refrigerant is as follows.

In cases where the refrigerant is commonly used, such as R-404a, R-507a, and R-448a, and for refrigeration (target temperature -25 to -18℃), the normal pressure of the refrigerant is 0.5 to 2.5 kg/㎠, and refrigeration ( If the purpose is a target temperature of -5 to 15℃, the normal pressure is 1 to 3.5kg/cm2, and if the purpose is air conditioning (target temperature 15℃ or higher), the normal pressure is 2 to 4.5kg/cm2.

Since the refrigerator 100 (including the refrigerator and air conditioner) does not need to be operated within the above pressure range, the refrigerator 100 stops operating, and if the pressure is out of the range, the refrigerator 100 restarts to adjust the temperature to the target temperature. It should work.

In order to measure the pressure of the low-pressure refrigerant in the refrigerant suction line 102a between the evaporator 101 and the compressor 102, a suction pressure sensor 21 is installed in the refrigerant suction line 102a to detect a range of -0.5 to 11 bar. ) is installed, and the low pressure measurement step of measuring the pressure with the suction pressure sensor 21 begins.

In the low pressure measurement step, a first conversion unit 22 linked to the sensor is configured to convert the analogue value of the pressure measured from the suction pressure sensor 21 into a digital signal and converts it into a digital value. It goes through a first current conversion step, and the first conversion unit 22 is preferably made of a transmitter.

The calculation unit 11 is configured to receive a digital signal (variable current) from the first conversion unit 22 through a first current conversion step and determine whether the value of the digital signal is within a set range by comparing it with a preset value, The calculation unit 11 compares and contrasts the values and goes through a calculation step.

It goes through a first switching step in which the first switch 23, which is configured to operate according to the result (True/False) determined by the calculation unit 11, is operated, and the first switch 23 is preferably made of a transistor.

After going through the first switching step, as shown in FIG. 2, the output terminal No. 16 of the first switch 23 is linked to the starting circuit of the compressor 102, so that the compressor 102 is stopped or operated. 100) The control stage is reached.

Therefore, when the compressor 102 is stopped, the refrigerator 100 also stops operating, and when the compressor 102 operates, the refrigerator 100 also starts operating, so that the target temperature of the refrigerator 100 is maintained. Refrigerant flows.

As the second automatic control system 1, the outdoor fan control unit 3 as shown in FIGS. 4 and 5 will be described.

The reason why the refrigerant pressure in the system must be maintained in an appropriate range in a refrigeration device is the same principle as maintaining the appropriate blood pressure in the human body. If the blood pressure is too high, it can lead to serious diseases such as blood vessel rupture, and conversely, if the blood pressure is too low, the Since sufficient blood is not supplied to every corner, each organ is unable to perform smooth physical activities.

Likewise, in the refrigerator 100, if the pressure at which the refrigerant is discharged from the compressor 102 is too high, serious problems such as pipe damage, overheating of the compressor 102, and increased power costs occur. Conversely, if the discharge pressure is too low, the refrigerant is connected to a long pipe. The expansion valve of the cooler in a freezer or refrigerator is unable to maintain the appropriate passing pressure, causing the cooler to not perform to its full potential.

In addition, in winter, the temperature is different depending on the installation location of each accessory equipment. Since the refrigerant pressure in the outdoor unit coil exposed to the outside is inevitably lower than the refrigerant pressure in the receiver, which is a tank that stores and supplies refrigerant gas in the machine room, the compressor ( If the pressure of the refrigerant discharged from 102) is not maintained at an appropriate level, the refrigerant is not smoothly transferred from the outdoor unit to the receiver, which reduces refrigeration efficiency and causes malfunction due to insufficient refrigerant circulation. Therefore, the pressure of the refrigerant discharged from the compressor 102) It is desirable to maintain it in the range of 12kg/cm2 to 15kg/cm2.

The outdoor fan control unit (3) receives the pressure value from one high-pressure sensor to control the pressure of the refrigerant discharged from the compressor (102) and creates a two-path circuit to mix them, so when it is controlled by only one path, problems with parts may occur. (100) We wanted to reduce the risk of becoming unable to drive by half.

As a configuration to achieve the above effect, the second automatic control system (1) measures the pressure of the refrigerant discharge line (102b) between the compressor (102) and the condenser (103) and controls the outdoor unit fan (not shown) accordingly. to control.

The outdoor fan is installed in the outdoor unit, and the outdoor unit is a device in which the condenser 103 is installed as one unit.

At this time, the control method varies depending on the number of fans installed in the outdoor unit.

If only one outdoor fan is installed, the speed of the outdoor fan is controlled.

When two or more outdoor unit fans are installed, half (rounded down) of the outdoor unit fans control the speed of the outdoor unit fan, and the other half (rounded down) of the outdoor unit fans are controlled by turning the outdoor unit fan on/off. .

Looking at the above configuration in more detail, it is as follows.

To measure the pressure of the refrigerant discharge line (102b) between the compressor (102) and the condenser (103), a discharge pressure sensor (31) capable of detecting a range of 0 to 30 bar is provided in the refrigerant discharge line (102b), and the discharge It begins with the high pressure measurement step of measuring pressure with the pressure sensor 31.

In order to receive the analog value measured from the discharge pressure sensor 31 in the high pressure measurement step, an outdoor fan transmission device 32 connected to 4 ~ 20 mA analog output terminals 23 and 24 in the drawing is provided. , it goes through an outdoor fan shifting step in which analog values are input and the speed of the outdoor fan is changed.

The output of output terminals 23 and 24 is a trigger signal.

Specifically, in the outdoor unit fan shifting step, the outdoor unit fan shifting device 32 receives the above trigger signal and increases the rotation speed of the outdoor unit fan according to the preset setting value as the pressure increases, and decreases the rotation speed of the outdoor unit fan as the pressure increases, thereby reducing the refrigerant discharge line. By maintaining the pressure at 102b, the outdoor unit fan control completion stage is reached in which the outdoor unit fan control is completed.

Since the outdoor fan shifting device 32 is installed to be interlocked with the power supply part of the outdoor fan, as a result, the outdoor fan shifting device 32 is immediately connected according to the pressure of the refrigerant discharge line 102b measured by the discharge pressure sensor 31. It is configured so that the fan speed of the outdoor unit can be changed.

In addition, as seen above, when a plurality of outdoor unit fans are provided, a configuration that can turn on and off half of the outdoor units is further provided.

The second conversion unit 33, which is a transmitter, is configured to convert the value measured from the discharge pressure sensor 31 into a digital signal, so that the second current conversion step is performed from the high pressure measurement step.

The calculation unit 11 is configured to determine whether the digital signal transmitted from the second conversion unit 33 is within a preset range, and a calculation step in which the calculation unit 11 determines the value is performed.

A second switch 34, such as a transistor switch, is configured to be linked to the calculation unit 11 to control the on/off operation of the outdoor fan according to the result value (True/False) determined in the calculation stage, and the second switch ( 34) applies power to output terminal No. 18 in the drawing to achieve an outdoor unit fan on/off stage in which the outdoor unit fan is turned on or off.

Therefore, according to the pressure of the refrigerant discharge line (102b) measured by the discharge pressure sensor (31), the speed of half of the outdoor unit fans is adjusted, and the other half of the outdoor unit fans are stopped or operated, reaching the outdoor unit fan control completion stage. It will be done.

As the third automatic control system 1, the compressor cooling control unit 4 as shown in FIGS. 6 and 7 will be described.

The compressor 102 is a device that increases the pressure of the refrigerant and inevitably generates heat. Therefore, if the heat generation of the compressor 102 is excessive, cooling is required and this is to be automatically adjusted.

A discharge temperature sensor 41 is configured in the refrigerant discharge line 102b to measure the temperature of the refrigerant discharge line 102b between the compressor 102 and the condenser 103, and the temperature is measured by the discharge temperature sensor 41. The temperature measurement step begins.

A third conversion unit 42, which is a transmitter, is configured to convert the analog temperature value measured from the discharge temperature sensor 41 into a digital signal, and the third current conversion step is converted into a digital value in the third conversion unit 42. is in progress.

The calculation unit 11 is configured to determine whether the digital signal transmitted from the third conversion unit 42 is within a preset range, and goes through a calculation step in which the calculation unit 11 outputs a result value (True/False).

A third switch 43 is configured to be linked to the calculation unit 11 to control the on/off operation of the injection valve installed in the compressor 102 according to the result of the calculation unit 11, and the third switch 43 is configured to control the on/off operation of the injection valve installed in the compressor 102 according to the result of the calculation unit 11. (43) enters the third switching stage where it is opened or closed.

In the drawing, voltage is applied to output terminal No. 20, so the injection valve 44 opens and goes through an injection valve opening and closing stage.

At this time, since the injection valve 44 must be operated electronically, it is preferably configured as an electromagnetic valve (solenoid valve).

Typically, when the temperature of the refrigerant discharged from the compressor 102 rises to 85°C, the injection valve 44 opens to inject and expand the refrigerant gas into the compressor 102, and the temperature of the compressor 102 itself decreases by absorbing the heat of evaporation. When the temperature deviation is adjusted to ±5℃, when the discharge temperature of the compressor (102) drops to 80℃, the injection valve (44) closes to stop cooling of the compressor (102), and when the temperature deviation exceeds the temperature deviation, the injection valve (44) opens again. ) is repeatedly opened to cool the compressor 102, ending in a compressor cooling step.

As the fourth automatic control system (1), the refrigerator control unit as shown in FIG. 8 will be described.

Among the configurations described above, a suction pressure sensor 21 configured in the refrigerant suction line 102a to measure the pressure of the refrigerant suction line 102a between the evaporator 101 and the compressor 102, the compressor 102, and Low pressure measurement that can check whether there is an abnormality in the compressor 102 by using the discharge pressure sensor 31 configured in the refrigerant discharge line 102b to measure the pressure of the refrigerant discharge line 102b between the condenser 103. Step and high pressure measurement step are performed respectively.

The first converter 22 and the second converter 33 are configured to convert each pressure value measured from the suction pressure sensor 21 and the discharge pressure sensor 31 into digital signals, respectively, to output digital signals. The digital signals converted from each step through the first current conversion step and the second current conversion step are transmitted to the calculation unit 11.

The calculation unit 11 simultaneously checks the suction pressure of the suction pressure sensor 21 and the discharge pressure of the discharge pressure sensor 31, and goes through a calculation step to check whether one of the two pressures is inappropriate.

When power is applied in the first switching step through the first switch 23 configured to control the on/off operation of the refrigerator 100 in conjunction with the calculation unit 11 in the calculation step, It goes through a compressor control step to emergency stop the compressor 102, which leads to an emergency stop of the refrigerator 100, so it is a safety system that can be treated as a refrigerator 100 control step.

In addition, in addition to the abnormal high pressure and abnormal low pressure mentioned above, although not shown in the drawing, the refrigerator 100 can be brought to an emergency stop even in the event of a refrigerant leak by detecting the refrigerant level.

In addition, in the event of an emergency stop, an alarm can be output to notify the user visually and audibly. However, since it is a general configuration, the description of the notification part will be omitted.

As the fifth automatic control system 1, the regulation control unit 5 as shown in FIGS. 9 and 10 will be described.

It begins with a low pressure measurement step of measuring the pressure from the suction pressure sensor 21 configured in the refrigerant suction line 102a to measure the pressure of the refrigerant suction line 102a between the evaporator 101 and the compressor 102.

A first conversion unit 22, which is a transmitter, is provided to convert the measured analog value into a digital signal, and a first current conversion step is performed to convert the previously measured pressure into a digital signal.

The digital signal transmitted from the first conversion unit 22 is provided in the calculation unit 11 to determine whether the value is within a preset range, and goes through a calculation step.

The calculation unit 11 outputs a signal by substituting the integrated time for the pressure value input in real time, and is provided with a TRIAC (triode for alternating current) to receive the signal. The triac transmission stage is performed in which the signal is transmitted.

The triac 51 is an electronic component used to control AC voltage and current by connecting two SCRs and switching them in both directions.

The triac 51 goes through a pulse wave generation step where it creates a pulse wave signal from the signal input from the calculation unit 11 and transmits it to the PWM valve 52 through output terminal No. 19 in the drawing.

The pulse wave is shown in the table image below.

PWM (Pulse Width Modulation) is a device that controls an analog circuit with a digital output and is a method of controlling the average voltage by changing the load (duty) ratio within a certain period.

As shown in FIG. 1, the regulation line 53 is connected so that the refrigerant suction line 102a between the evaporator 101 and the compressor 102 and the refrigerant discharge line 102b between the compressor 102 and the condenser 103 communicate with each other. ) is composed.

The PWM valve 52 is configured in the regulation line 53, and the PWM valve control step is completed in which the regulation line 53 is controlled to communicate or block by opening or closing the PWM valve 52.

When the regulation line 53 is opened, the discharge gas is sprayed into the suction pipe to prevent the pressure on the low pressure side from dropping excessively.

In addition, when the load on the evaporator 101 is reduced and the low pressure drops to just before the set pressure to stop operation, and the refrigerator 100 is operated for a long time, the refrigerator 100 overheats and oil foaming increases, increasing the risk of damage to the refrigerator 100 and the evaporator 101. Frosting occurs frequently, and when the load is low, the freezer (100) heats up frequently, shortening its lifespan or increasing power costs. Therefore, it is important to maintain an appropriate low pressure to minimize the freezing of the freezer (100) when the load is low. do.

As shown in FIG. 9, the above configuration is further provided with an interlock circuit (54) so that the PWM valve 52 is also locked when the temperature or humidity is satisfied and the refrigerator 100 is stopped. It receives the operation signal (on/off signal of the refrigerant supply valve) of (100) and opens and closes the PWM valve (52) by operating the auxiliary relay.

That is, when the load-side cooler electromagnetic valve is turned on, the PWM valve 52 operates, and when the load-side cooler electromagnetic valve is turned off, the PWM valve 52 does not operate.

Therefore, when all the electronic valves for cooling operation are closed in the refrigerator 100, the power to the PWM valve 52 is cut off because the circuit is configured in the interlock unit 54, and the discharge gas cannot be sprayed to the suction side, so the pressure rises to the low pressure set value. Going down, the freezer 100 is stopped.

As described above, the most preferred embodiments of the present invention have been described in the detailed description of the present invention, but various modifications may be made without departing from the technical scope of the present invention. Therefore, the scope of protection of the present invention should not be limited to the above-mentioned embodiments, but should be recognized to the technologies in the patent claims described later and to equivalent technical means from these technologies.

100:Freezer
101: Evaporator
102: Compressor
102a: Refrigerant suction line
102b: Refrigerant discharge line
102c: Auxiliary refrigerant line
102d: High and low pressure pressure switch
103: Condenser
1:Automatic control system
11: Computation unit
2: Compressor control unit
21: Suction pressure sensor
22: First conversion unit
23: 1st switch
3: Outdoor fan control unit
31: Discharge pressure sensor
32: Outdoor fan transmission device
33: Second conversion unit
34: Second switch
4: Compressor cooling control unit
41: Discharge temperature sensor
42: Third transformation unit
43: Third switch
44: Injection valve
5: Regulation control unit
51:Triac
52:PWM valve
53: Regulation line
54: Interlock part

Claims (8)

In the refrigerator automatic control system (1) including an evaporator (101), a compressor (102), and a condenser (103),
A compressor control unit 2 configured in the refrigerator 100 to control the compressor 102 according to the suction pressure of the compressor 102;
an outdoor fan control unit 3 configured in the refrigerator 100 to control the outdoor fan according to the discharge pressure of the compressor 102;
A compressor cooling control unit (4) configured in the refrigerator (100) to control the temperature of the compressor (102);
A regulation control unit (5) configured in the refrigerator (100) to regulate the suction pressure of the compressor (102);
includes,
The compressor control unit (2) is,
A suction pressure sensor 21 configured in the refrigerant suction line 102a to measure the pressure of the refrigerant suction line 102a between the evaporator 101 and the compressor 102;
A first switch (23) configured to turn on/off the compressor (102) according to the pressure value measured from the suction pressure sensor (21);
includes,
The outdoor fan control unit (3) is,
A discharge pressure sensor 31 configured in the refrigerant discharge line 102b to measure the pressure of the refrigerant discharge line 102b between the compressor 102 and the condenser 103;
an outdoor fan transmission device (32) configured to control the rotational speed of the outdoor fan according to the pressure value measured from the discharge pressure sensor (31);
a second switch (34) configured to control the on/off operation of the outdoor fan according to the pressure value measured from the discharge pressure sensor (31);
includes,
The compressor cooling control unit (4),
A discharge temperature sensor 41 configured in the refrigerant discharge line 102b to measure the temperature of the refrigerant discharge line 102b between the compressor 102 and the condenser 103;
A third switch 43 configured to control the on/off operation of the injection valve 44 installed in the compressor 102 according to the temperature value measured from the discharge temperature sensor 41;
Included in the compressor cooling control unit (4) is that when the temperature of the refrigerant discharged from the compressor (102) rises above 85°C, the injection valve (44) opens and injects and expands the refrigerant gas into the compressor (102) to absorb the heat of evaporation. When the temperature of the compressor 102 itself decreases and the discharge temperature of the compressor 102 falls below 80°C, the injection valve 44 closes to repeatedly stop cooling of the compressor 102 to control the temperature of the compressor 102. do,
The regulation control unit (5),
A regulation line 53 configured to communicate with the refrigerant suction line 102a between the evaporator 101 and the compressor 102 and the refrigerant discharge line 102b between the compressor 102 and the condenser 103;
A triac (51) configured to generate a pulse wave signal according to the value measured from the suction pressure sensor (21);
A PWM valve (52) that opens and closes according to the pulse wave signal received by the triac (51) to prevent the low pressure side pressure from dropping excessively by spraying the discharge gas into the suction pipe through the regulation line (53);
An interlock unit 54 configured to turn off the PWM valve 52 by an interlocked relay when the refrigerator 100 stops operating;
A refrigerator automatic control system comprising: delete delete delete delete delete delete delete

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