JPH02115674A - Controller for cooler - Google Patents

Abstract

PURPOSE:To extend the stopping period of a compressor and to save electricity by calculating the operating ratio from the ratio of the operating period to the stopping period of the compressor, and increasing the set temperature range in case of the low operation ratio. CONSTITUTION:When the count of a counter T is '0' or more, i.e., the operating ratio is smaller than 40% in low operation ratio, LR flag is set, while when the ratio is larger than 40% in high operation ratio, the LR flag is reset. Then, the counter T is reset. When the flag is set, an output port P2 is set to 'H', and a lower limit temperature is set to -24 deg.C. The output port P2 is set to 'L', and an upper limit temperature is set to -16 deg.C. A mean target temperature is also set to -20 deg.C. That is, a microcomputer 13 sets the upper limit temperature to -18 deg.C and the lower limit temperature to -22 deg.C in case of high operation ratio by checking the ratio of one cycle from the previous stop to the stop of this time each time the compressor 12 is stopped, and sets the upper limit temperature to -16 deg.C and the lower limit temperature to -24 deg.C in case of the low ratio to increase the set temperature range.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a control device for a cooling device that operates a compressor to cool a space to be cooled.

(b) Conventional technology A conventional type cooling device, for example, in a refrigerator, the temperature range is set based on the upper and lower temperature limits inside the refrigerator, and the compressor is operated when the temperature rises to the upper limit temperature and stops when the temperature falls to the lower limit temperature. By doing so, the temperature inside the refrigerator is controlled to the target temperature on average. At this time, the operating condition of the compressor is as follows: In the summer, the outside temperature is high, so the temperature inside the refrigerator rises quickly, and it is difficult to cool down, so the operating time is long; The driving time tends to be short and the stop time tends to be long. However, even in winter when cooling is not particularly necessary, if cooling operation is performed in the same temperature range as in summer, unnecessary operation is often performed no matter how low the operating rate is.

Therefore, in the past, as shown in Japanese Patent Application Laid-Open No. 56-130573, a sensor was installed to detect the outside temperature, and when the outside temperature was low, the temperature range was expanded to extend the period when the compressor was stopped. .

(c) Problems to be solved by the invention In this way, a device that is controlled based on outside temperature requires a special sensor, and in addition, cooling is required when a large heat load is stored inside the refrigerator in the winter. Despite this, there was a problem that the temperature range was large and it was difficult to enter cooling operation.

(d) Means for Solving the Problems In order to solve such problems, the present invention provides a control device for a cooling device that detects the temperature of a space to be cooled and adjusts the temperature within a predetermined set temperature range. The operating rate is calculated based on the ratio between the operating period and the stopping period of the machine, and in the case of a low operating rate, the set temperature range is expanded.

(E) Effect According to the present invention, the set temperature range can be changed without using an outside temperature sensor. Furthermore, it is possible to cope with load fluctuations in the space to be cooled.

(f) Example Next, the first example of the case where the present invention is applied to a refrigerator will be described.
This will be explained based on FIGS. 4 to 4. In FIG. 1, 1 is a refrigerator, and 2 and 3 are a freezer compartment and a refrigerator compartment that are vertically divided by a partition wall 4 in the refrigerator. 5 is partition board 7
This is a cooler housed in a cooling chamber 8 formed behind the freezing chamber 2. The cold air cooled by the cooler 5 is sucked in by an upper blower 6 and sent to the freezer compartment 2 through a partition plate 7.
It is supplied to the refrigerating chamber 3 from the discharge hole formed in the 11, and each chamber is cooled. The discharge hole 11 is opened and closed by a damper (not shown), thereby controlling the temperature inside the refrigerator compartment 3. 12 is a compressor, which together with the cooler 5 constitutes a predetermined refrigerant circuit. After the cold air discharged into the freezing chamber 2 circulates within the room, it flows into the return passage 9 through the suction hole 9A formed in the partition wall 4 and returns to the cooling chamber 8. After the cold air discharged into the refrigerator compartment 3 circulates within the room, it flows into the return passage 10 from the suction hole 10A on the lower front surface of the partition wall 4 and returns to the cooling compartment 8.

Next, FIG. 2 shows the control circuit of the refrigerator 1. 13 is a microcomputer, the output of the comparator 514 is connected to the PI, and the resistor 1 is connected to the output port P2.
5 is connected. A voltage obtained by dividing the DC power supply VDD by a variable resistor 16 and a resistor 17 is input to the ten input terminal of the comparator 14, and a positive feedback resistor 18 is connected between the ten input terminal and the output of the comparator 14. A resistor 15 is connected to the input terminal. 19 is a sensor that detects the temperature inside the freezer compartment 2;
A terminal voltage of a sensor 19 consisting of a negative characteristic thermistor, which is obtained by dividing VDD with a resistor 20, is inputted to one input terminal of a comparator 14. The coil of the relay 21 is connected to the output port P3 of the microcomputer 13, and the relay 2
A contact point 1 is connected to an alternating current power supply AC in series with a parallel circuit of a blower 6 and a compressor 12. Furthermore, the coil of a relay 22 is connected to the output terminal P4 of the microcomputer 13, and the contact point of the relay 22 is connected to the defrosting heater 2 of the cooler 5.
3 in series with the power supply AC.

Next, the microcomputer 13 in FIGS. 3 and 4
The operation will be explained using a flowchart showing the software. In step 25, it is determined whether the compressor 12 is currently in operation. Here, assuming that the compressor 12 has just stopped, the process proceeds to step 26, where the microcomputer 9-13 adds the count A to the counter T that it has as its function. It is assumed that the counter T has been reset at this time. Next, in step 27, it is determined whether the counter T has overflowed, and if not, the process proceeds to step 30. In step 30, it is determined whether the cooler 5 is currently being defrosted.

Here, the microcomputer 13 accumulates the operating time of the compressor 12, and sets the output port P4 to a high potential (hereinafter referred to as "H") equal to VDD at a predetermined accumulated time, and closes the contacts of the relay 22. Close it and energize the heater 23,
Defrosting of the cooler 5 is started, and a predetermined sensor (not shown) senses the defrosting end temperature (for example, +10°C) of the cooler 5, and the output port P4 is set to a low potential (hereinafter referred to as "L") equal to the ground potential.
” ), open the contact of the switch 22 and peak -
23 is de-energized to complete defrosting.

If the cooler 5 is not being defrosted in step 30, the process advances to step 31 and the input capo (PI) which is the output of comparison 1B14
is "H", and if it is "H", go to step 33 and turn output port P3 to r) (as J, close the contacts of relay 21 and energize compressor 12 and blower 6 to operate. When Capo) PI is "L", the process proceeds to step 32, where the output port P3 is set to "L" and the contacts of the relay 21 are opened to stop the compressor 12 and the blower 6.

Here, the comparator 14 determines whether its output (P2) is "H" or "
When P2 is "H", the output is reversed to "L" when the temperature of the freezer compartment 2 is -24℃, for example, and the output is When port P2 is "L", it is reversed to "L" at -22°C. That is, the comparator 14 outputs an output at the lower limit temperature of -24°C or -22°C.
(From J to "L", in steps 31 to 32 compressor 1
Stop 2.

Also, the comparator 14 outputs an output when its output is "L")
When P2 is "H", the output is reversed to rHJ when the temperature of the freezer compartment 2 is, for example, -18°C, and when output port P2 is "L", the output is reversed to rL (J) at -16°C. vessel 14
changes the output from "L" to "L" at the upper limit temperature of -18℃ or -16℃.
H'', and the compressor 12 is operated in steps 31 to 33.

If the input port PI is "L" in step 31, the compressor 12, etc., continues to be stopped in step 32, and in step 24, it is determined whether the compressor 12 has switched from the operating state to the stopped state. Then, proceed to step 41 and determine whether the capo) PI is r) (J, and currently r HJ
If not, proceed to step 43 and determine whether the LR flag is set. If it is assumed that it is currently reset, proceed to step 47 and set output capo P2 to "H" and set the upper limit temperature of the freezer compartment 2 as described above. The temperature is set to -18° C. and the process proceeds to step 48, where it is again determined whether defrosting is in progress, and if defrosting is not in progress, the process returns to the previous step.

The above is repeated, and the counter T continues to add the count A while the compressor 12 is stopped.

As the compressor 12 continues to stop, the temperature of the freezer compartment 2 decreases to 118.
When the temperature rises to 0.degree. C., the output of the comparator 14 is reversed to "H", so in step 33, the compressor 12 (and the blower 6 as well) is operated. Further, from step 41, the process proceeds to 42, and since the LR flag has been reset, the process proceeds to step 46, where the output port P2 is set to "L" and the lower limit temperature is set to -22°C. Next, from step 25, the process proceeds to 29, where the counter T subtracts the count B.

The above steps are repeated to operate the compressor 12, the counter T adds up the count B, and when the temperature of the freezer compartment 2 drops to 122° C., the output of the comparator 14 is reversed to "L". This causes the compressor 12 to be stopped in step 32. As a result, the temperature inside the freezer compartment 2 is controlled to an average of -20°C.

Next, from step 34, due to this stop, step 35
Proceed to. (Proceeding from step 34 to step 35 is the compressor 12.
This is only when switching from running to stopped. ) Since the OF flag is set to 1 in step 35, the process proceeds to step 37 to determine whether the count of counter T is smaller than O.

Here, if count A is 2 and count B is 3, the reason why the count of counter T becomes 0 is because the operating rate of the compressor 12 (operating period/(operating period + stop period)) is A/(A+
P1), that is, at 40%. Therefore, the count is O
When it is smaller, the operating rate is greater than 40%, and when it is greater than or equal to 0, it is less than 40%.

When the count of the counter T is 0 or more in step 37, that is, when the operating rate is a low operating rate of 40% or less, the LR flag is set in step 39, and when the count is smaller than 0, that is, the operating rate is 40%. When the operating rate is higher, the LR flag is reset in step 38. Next, in step 40, the counter T is reset.

When the LR flag is set, the process proceeds from step 42 to step 44, where capo P2 is set to "H" and the lower limit temperature is set to -24 DEG C. as described above. Further, from step 43, the process proceeds to step 45, where capo P2 is set to "L" and the above-mentioned upper limit temperature is set to -16 DEG C. The average target temperature is still 12
It is 0°C.

That is, each time the compressor 12 stops, the microcomputer 13 checks the operating rate of one cycle from the previous stop to the current stop, and when the operating rate is high, it sets the upper limit temperature to -18°C and the lower limit temperature. -22°C, and when the operating rate is low, the upper limit temperature is -16°C and the lower limit temperature is -24°C, and the set temperature range is expanded.

When the operating rate is low, there is no need for cooling so much, so there is no problem in extending the stop period of the compressor 12 by expanding the set temperature range.

If defrosting is started during the above control, step 30
The process then proceeds to step 32 to stop the compressor 12, and the process proceeds to steps 34 and 35 to perform the above-mentioned processing. From step 48, the process proceeds to step 51, where the LR flag is forcibly reset and a high operating rate state is established. Therefore, after defrosting is completed, compressor 1
When No. 2 is operated, the temperature range is at a high operating rate, so that the interior of the refrigerator, where the temperature is rising, can be quickly cooled after defrosting is completed.

In addition, if the compressor 12 is stopped for a long time and the count of the counter T overflows, steps 27 to 28 are performed.
The process proceeds to step 35 and sets the OF flag, then proceeds from step 35 to step 36 to reset the OF flag, and in step 39 sets the LR flag, so even if the count of counter T becomes an abnormal value, the It is possible to enter a low operating rate state.

Although the present invention is applied to a refrigerator in the embodiment, the present invention is not limited thereto and may be applied to other cooling devices. Further, in the embodiment, the operation rate was determined at 40%, but the operation rate may be determined at other operation rates by appropriately setting the values of Curran A and B.

(G) Effects of the Invention According to the present invention, it is possible to expand the set temperature range when the compressor is in a low operating rate state, thereby extending the stop period of the compressor, thereby saving power. In particular, since the temperature range can be changed without using an outside temperature sensor, it is possible to reduce the number of parts and reduce the failure rate, and when the load on the space to be cooled increases, the operating rate is expanded, so the temperature range can be quickly restored. The cooling effect is not impaired.

[Brief explanation of the drawing]

Each figure shows an embodiment of the present invention; FIG. 1 is a longitudinal sectional view of a refrigerator, FIG. 2 is a control circuit diagram of the refrigerator, and FIGS. 3 and 4 are flow charts showing software of a microcomputer.

Claims (1)

[Claims] 1) In a device that detects the temperature of the space to be cooled and adjusts the temperature within a predetermined set temperature range, the operating rate is calculated based on the ratio of the operating period and the stopping period of the compressor, and in the case of a low operating rate, the A control device for a cooling device characterized by expanding a set temperature range.