JPH0746010B2 - Operation control device for refrigerator - Google Patents

Description

TECHNICAL FIELD The present invention relates to a refrigerator operation control device.

FIG. 4 shows the configuration of a conventional refrigerator operation control device and its problems. Reference numeral 1 is an inside temperature detecting means for detecting an inside temperature, 2 is a set temperature detecting means for detecting a set temperature, 3 is an amount of frost accumulated in a cooler, and a defrosting start signal is given when a predetermined amount of frost is reached. Defrosting start detecting means 4 for outputting is a defrosting ending detecting means for detecting when the temperature of the cooler becomes a predetermined temperature or more during defrosting and ending the defrosting. Reference numeral 5 is a control means, which is an input terminal I ₀ , I
_{It has 1} , ₁ , ₂ and I ₃ and output terminals ₀ and ₁ . Then, the inputs from the in-compartment temperature detecting means 1 and the set temperature detecting means 2 are compared, and the rotation speed of the compressor 6 is determined according to the temperature of both.

For example, in the case of "inside temperature <set temperature", the compressor 6 is stopped, in the case of "inside temperature> set temperature", the compressor 6 is operated at a high rotation speed, and when inside temperature = set temperature It is determined that the compressor 6 is operated at a low rotation speed and the like, and is output from the output terminal ₀ . Reference numeral 7 denotes an operation control means, which is, for example, a transistor inverter which receives the rotation speed determined by the control means 5 and operates the compressor 6 at the rotation speed.

Reference numeral 8 denotes a relay, which has a contact 8'and turns on / off the contact 8'by the output of the control means 5 to turn on / off the defrosting heater 9.

Considering the time when the power of the refrigerator is turned on for the first time in such a configuration, the inside of the refrigerator is almost the same as the outside air temperature, and the inside temperature> the set temperature, and the control means 5 operates the compressor 6 at a high rotation speed. Decide to do. Therefore, the compressor operates at a high rotation speed. The change of the input current applied to the compressor 6 at this time is shown in FIG. Fifth
Point A in the figure is the peak value of the motor current. The time T from the start of operation to the peak of the current value is usually about
It takes 30 minutes, which varies depending on the outside temperature, the temperature inside the refrigerator, and the cooling system.

For this reason, a very large current flows at point A, and an element such as a transistor capable of withstanding this current must be used for the operation control means 7, which is expensive.

OBJECTS OF THE INVENTION Therefore, the present invention reduces the current peak value at point A shown in FIG. 5 to reduce the cost of the operation control means by making elements such as transistors used in the operation control means a small capacity. It is an object of the present invention to provide a control device capable of coping with changes in outside air temperature, in-chamber temperature and cooling system.

To achieve this object, the present invention provides a current detection means for detecting the input current supplied to the compressor of the refrigerator, and when the input current supplied to the compressor exceeds a predetermined value, The rotation speed of the compressor determined by is reduced, and if it becomes less than a predetermined value after that, the rotation speed determined by the internal temperature and the set temperature is controlled so as to reduce the current peak value after the power is turned on.
It is designed to operate stably even with changes in the outside temperature, the inside temperature, and the cooling system.

Description of Embodiments An embodiment of the present invention will be described below with reference to the accompanying drawings. First
The figure is a diagram showing a configuration of an embodiment of the present invention, the internal temperature detection means 1, set temperature detection means 2, defrost start detection means 3, defrost end detection means 4, control means 5, compressor 6, The relay 8 and the heater 9 have the same structure as the conventional example.

Reference numeral 7 denotes an operation control means, which is a DC brushless motor drive circuit that switches the voltage applied to each phase of the winding while detecting the rotation of the motor of the compressor 6 and changes the rotation speed by controlling the voltage applied to the motor. (Hereinafter referred to as operation control means). Reference numeral 10 is a current detecting means for detecting an input current applied to the compressor 6 by, for example, a CT (current transformer) 10 'and sending an output to the control means 5.

The operation will be described below with reference to FIG.

In one step, the internal temperature detected by the internal temperature detecting means 1 is input from the input terminal I ₀ . Next, in step 2, the set temperature detected by the set temperature detecting means 2 is input from the input terminal I ₁ . Next, in 3 steps, the inside temperature input in 1 step is compared with the set temperature input in 2 steps, and the rotation speed of the compressor 6 is determined in 4 steps. In 5 steps, the input current value given to the compressor 6 detected by the current detecting means 10 is input. In 6 steps, it is judged whether or not the current value input in 5 steps is larger than a predetermined value, and if it is larger or equal, it proceeds to 7 steps, and if it is smaller, it proceeds to 8 steps and the rotation speed determined in 4 steps is set to the operation control means. Output to 7. This 6
If the result of the determination in step 8 is to proceed to step 8, the input current value is in a state in which there is a margin for the elements of the operation control means 7, and the determined rotation speed is output as it is. Next, in 9 steps, it is judged from the output of the defrosting start detecting means 3 whether or not defrosting is started. If defrosting is started, the operation proceeds to 10 steps. Normally, the above operation is repeated. When the compressor 6 is operated and the cooling operation is performed when the power is turned on or after the defrosting is completed, the cooling load of the refrigerator gradually increases and the compressor 6
When the input current value given to
From step S7, the control unit 5 outputs the intermediate rotation speed to the operation control unit 7 with respect to the rotation speed determined in Step S4, and the process proceeds to step S9. If defrosting start is detected in 9 steps, the process proceeds to 10 steps, and in 10 steps, the rotation speed of the compressor 6 is set to 0 rotation (OFF) and the output terminal
_The operation control means 7 outputs from ₀ . Next, in 11 steps,
A defrost signal is output from the output terminal _{1, the} relay 8 is turned on, and the heater 9 is energized to start defrosting.

Next, if there is no output by the output of the defrosting completion detecting means 4 in step 12, the process returns to step 12 and the output of the defrosting completion detecting means 4 is taken in again and defrosting is continued during this period. If there is an output, the operation proceeds to step 13 and the heater 9 is turned off to end the defrosting and returns to step 1.

Thus, as shown in FIG. 3, when the refrigerator is powered on for the first time, the compressor 6 starts operating at a high rotational speed as described above, and the temperature difference between the inlet and the outlet of the cooler disappears. Since the load of the compressor 6 increases and the current value tends to exceed a predetermined value, that is, point B in FIG. 3, at this time, the rotation speed of the compressor 6 is operated at an intermediate rotation speed and the current value is controlled to decrease. . Further, when the current value falls below the predetermined value, the cooling performance is not significantly affected by returning the operation speed determined by the original internal temperature and the set temperature.

Therefore, by detecting the input current applied to the compressor 6,
By operating the compressor 6 at an intermediate speed when the current value is higher than a predetermined value, it is possible to reduce the peak current as in the point A in FIG. The element can be made small in capacity, and the configuration of the operation control means 7 can be made inexpensive. Further, even if the time to the current peak changes due to changes in the outside air temperature, the temperature inside the refrigerator, and the cooling system, it is possible to prevent excessive current, and stable operation is possible.

Furthermore, not only when the power is turned on, but also the peak current during operation after defrosting can be reduced.

3a and 3c, a shows the characteristics of the present invention, b shows the characteristics of the conventional example, and in FIG. 3b, c shows the inside temperature,
D indicates the cooler outlet temperature, and E indicates the cooler inlet temperature.

EFFECTS OF THE INVENTION As is clear from the above description, the operation control device for a refrigerator of the present invention includes current detection means for detecting the input current supplied to the compressor of the refrigerator, and the input current supplied to the compressor exceeds a predetermined value. In this case, the number of revolutions of the compressor determined by the internal temperature and the set temperature is reduced, and if the rotational speed falls below a predetermined value, the rotational speed determined by the internal temperature and the set temperature is restored. The elements such as transistors used for the operation control means can be made to have a small capacity, can be made inexpensive, and have no great influence on the cooling performance. In addition, stable operation can be realized even with changes in the outside air temperature, the inside temperature, and the cooling system.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of an operation control device for a refrigerator of the present invention, FIG. 2 is a flow chart, and FIG. 3 is a diagram showing changes in input current when the operation control device of the present invention is used. FIG. 4 is a diagram showing a configuration of a conventional refrigerator operation control device, and FIG. 5 is a diagram showing a change in input current after turning on a power source by a conventional control method. 1 ... internal temperature detecting means, 2 ... set temperature detecting means, 5
...... Control means, 7 …… Operation control means, 10 …… Current detection means.

Claims (1)

[Claims] Claim: What is claimed is: 1. An inside temperature detecting means for detecting the inside temperature,
Input from the set temperature detecting means for detecting the set temperature of the inside temperature, the current detecting means for detecting the input current given to the compressor of the refrigerator, the inside temperature detecting means, the set temperature detecting means and the current detecting means The control means for determining and sending out the number of revolutions of the compressor and the operation control means for operating the compressor at the number of revolutions determined by the control means, and the input current given to the compressor exceeds a predetermined value. In this case, the number of revolutions of the compressor determined by the internal temperature and the set temperature is reduced, and if the rotational speed falls below a predetermined value, the refrigerator is controlled to return to the rotational speed determined by the internal temperature and the set temperature. Operation control device.