JPH02166378A - Control device for refrigerator - Google Patents

Abstract

PURPOSE:To make it possible to cut off consumption power loss and increase cooling speed after the restarting of a compressor by providing a control means which changes the rotary speed of said compressor so that a pressure value on a higher pressure side in a refrigeration circuit may exceed a preset value before halting the operation of said compressor. CONSTITUTION:A detected temperature and a preset temperature inside a refrigerator are read into a control means 3 from detections means 1 and 2 where differential temperature is calculated. When differential temperature is judged to be smaller than a preset value and a compressor 5 is forced to end its operation very soon, signals detected by pressure detection components 8a and 8b are incorporated into a pressure detection means 8 where a differential pressure between a high pressure side and a low pressure is calculated and the calculated value is compared with a preset value, thereby changing the rotary speed so that a pressure value on a higher pressure side in a refrigeration circuit before suspension may exceed a preset value. This construction makes it possible to maintain the refrigerant after the suspension of the compressor 5 around a state available before the suspension, minimize power consumption after the restarting, and return the temperature inside the refrigerator promptly back to the state before the suspension.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a refrigerator control device that performs variable speed control of a pressure wI machine.

[Conventional technology]

Figures 10 and 11 are, for example, published in Japanese Patent Application Laid-Open No. 63-17372.
1 is an overall configuration diagram showing a conventional refrigerator control device disclosed in the above publication, and a flowchart showing its operation. In FIG. 10, 1 is a temperature detection element 1 such as a thermistor.
2 is a set temperature detection means for detecting the set temperature by a signal from the variable resistor 2a for setting the inside temperature; 3 is from these detection means 1 and 2; This is a control means that outputs operation control commands in response to signals from the controller, and is composed of a microcomputer or the like. 4
is an operation control means for the compressor 5, which receives an operation control command from the control means 3 and controls the compressor 5 at variable speed. Reference numeral 6 indicates the entire refrigerator, and reference numeral 7 indicates a freezer compartment disposed above the refrigerator 6. Note that the control means 3 is adapted to change the rotational speed of the compressor 5 in accordance with load fluctuations within the refrigerator. that time,
The difference between the detected temperature inside the refrigerator and the set temperature is assigned a rank for each certain range, and the operating frequency of the compressor 5 is also set for each certain stage to perform variable speed control of the compressor 5. Next, the operation of the conventional refrigerator control device will be explained with reference to flowchart 1 in FIG. This flowchart 1 shows a part of the operation in the control program stored in the microcomputer. 8114 shows the operation of determining the operating frequency of the 8114. First, the difference ΔT between the detected temperature Ta in the refrigerator and the set temperature Ts is determined based on the signals from the internal temperature detection means 1 and the set temperature detection means 2 (step 101), and the value of the temperature difference - T is determined (step 101). Step 102). Then, according to this determination result, for example, the temperature difference -T is J
If T=T, the operating frequency F of the compressor 4 is determined to be Fl (step 103), and if AT=T2, F=F.
2 (step 104). That is, the operating frequency F is uniquely determined based on the value of the temperature difference -T (steps 103 to N). At this time, programming is such that when the difference AT between the detected temperature Ta and the set temperature TsO is small, the operating frequency F of the compressor 4 is increased.

[Problem to be solved by the invention]

A conventional refrigerator control device is configured as described above, and uniquely determines the operating frequency of the compressor based on the difference between the detected temperature inside the refrigerator and the set temperature. As a result, the compressor rotation speed immediately before the stop is low, and the pressure difference between the high pressure side and the low pressure side is small. out of control,
The efficiency of the refrigeration cycle decreases, the power consumption of the refrigerator increases, and the time required for the refrigeration cycle to stabilize after restarting the compressor becomes longer (which may lead to worsening of power consumption or a decrease in the cooling speed inside the refrigerator). There was a problem. This invention was made to solve the above problems, and it is possible to reduce the power consumption of the refrigerator.
The purpose of the present invention is to obtain a control device for a refrigerator that has a fast cooling speed after restarting a compressor and has excellent food preservation properties.

[Means to solve problems] A refrigerator control device according to the present invention is a refrigerator control device that controls a compressor at variable speed according to the difference between a detected temperature inside the refrigerator and a set temperature. The compressor is equipped with a control means for changing the rotational speed of the compressor so that the pressure value becomes equal to or higher than a certain set value. [Effect]

In this invention, the control means changes the rotational speed of the compressor so that the pressure value on the high pressure side in the refrigerant circuit before the compressor stops is equal to or higher than a certain set value. The state of the refrigerant can be maintained close to the state of the refrigerant before the compressor is stopped, so there is less loss when the compressor is stopped, and unnecessary power consumption loss after restarting can be reduced. Also,
Since the state of the refrigerant quickly stabilizes after restarting, it is possible to quickly return the temperature inside the refrigerator to the state before the compressor was stopped.

【Example】

An embodiment of the present invention will be described below with reference to the drawings. Figure 1 shows a refrigerator according to this invention! 1 is an overall configuration diagram showing a first embodiment of the 1J control device, and FIG. 2 is a refrigerant circuit diagram thereof. In Figure 1, the same symbols as in Figure 10 are the same.
or a considerable portion. A temperature detection element 1a such as a thermistor is provided in the freezer compartment 7 of the cold Mj 16, and its detection signal is input to the internal temperature detection means 1. Also,
A variable resistor 2a for setting the internal temperature is provided on the front surface of the freezer compartment door, and its detection signal is input to the set temperature detection means 2. Then, the signals from the chamber temperature detection means 1 and the set temperature detection means 2 are taken into the control means 3, and the operating frequency of the pressure w1 machine 5 is calculated based on the signals.
An operating frequency signal is sent to the llT means 4. Further, the operation control means 4 receiving the signal controls the rotation speed of the compressor 5. The control means 3 has a built-in microcomputer, and is adapted to change the rotational speed of the compressor 5 in accordance with changes in the load inside the refrigerator. Moreover, pressure detection elements 8a are provided in the high pressure part and the low pressure part of the refrigerant circuit, respectively.
, 8b are provided, and the detection signal is inputted to the pressure detection means 8, converted into a digital quantity, and outputted to the control means 3. In FIG. 2, 5 is a compressor that compresses refrigerant gas, 9 is a condenser that liquefies the refrigerant gas compressed to a high temperature and high pressure by the compressor 5, and 10 is a condenser that liquefies the liquid refrigerant that has been liquefied by the condenser 9 to a low temperature. This is an evaporator that performs a refrigerating action by a capillary tube that lowers the pressure, and a capillary tube 11 that evaporates the low-temperature, low-pressure refrigerant from the capillary tube 10. The refrigerant gas vaporized in the evaporator 11 is compressed again in the compressor 5. . 13 is the capillary tube 10 and the coagulation w3
This is a differential pressure valve installed in the conduit 12 with the vessel 9, and this differential pressure valve 1
3 is supplied with the pressure on the suction side of the compressor 5 through the pressure pipe 15, and the differential pressure valve 13 is operated by this compressor suction side pressure PL and the discharge side pressure PH of the IAM device 9. . 14 is provided in a pipe connecting the refrigerant outlet side of the evaporator 11 and the suction side of the compressor 5;
This is a check valve to prevent backflow of refrigerant when the system is stopped. Further, the low pressure PL generated at the suction side (low pressure side) section D of the compressor 5 is detected by the pressure detection element 8b, and the high pressure PL generated at the discharge side (high pressure side) section 0 of the compressor 5 is detected by the pressure detection element 8b.
is detected by the pressure detection element 8a. Next, the operation of the refrigerator control device of this embodiment configured as described above will be explained with reference to flowchart 1 in FIGS. 3 and 4. Flowchart 1 in FIG. 3 shows the main program of the entire control device.
is stored in First, after initial setting in step 110, the subsequent main routine begins. That is, in step 120, the detected temperature and set temperature inside the refrigerator are read from the respective detection means 1 and 2 into the control means 3, and in step 130, the temperature difference therebetween is calculated. Next step 14
0, it is determined whether the temperature difference AT is greater than or equal to a certain set value A, and Δ
If T≧A, proceed to step 150, and the temperature difference is 4T.
A new set rotation speed N new for the pressure mms is determined according to the pressure mms, and the rotation speed N new is output to the operation control means 4 in the next step 160. Further, in step 140, if it is determined that the temperature difference, IIIT, is smaller than a certain set value A, that is, if the compressor 5 is close to stopping, the process proceeds to step 170 and step 180. FIG. 4 is a flowchart 1 showing details of the processing routine at steps 170 and 180. First, in step 171, the signals detected by the pressure detection elements 8a and 8b are taken into the pressure detection means 8, and are digitized into a high pressure side pressure value PH and a low pressure side pressure value PL. Pressure value P1. A pressure difference ΔP between l and PL is calculated. In step 181, a certain set value B and the value of the pressure difference 7jP are compared, and if 4P≧B, the process returns to step 150 shown in FIG. 3, and the rotation speed Nnew set by the temperature difference ΔT is determined. Also, -PCB
If so, proceed to the next step 182. Here, the current rotation speed N now is compared with the upper limit rotation speed N wax of the compressor, and if the current rotation speed N now is the upper limit rotation speed Nmax, the process moves to step 184 and the current rotation speed N n
The value of ow is set as the new set rotation speed N new. However, if it is determined in step 182 that the current rotational speed N now is smaller than the upper limit rotational speed Nmaχ,
Proceeding to step 183, the current rotation speed N now plus the additional rotation speed n is set as the new set rotation speed N ne
Let it be w. Then, in the next step 185, it is determined whether or not the internal temperature of the refrigerator meets the compressor OFF condition. If it is determined that the temperature is under the OFF condition, the process moves to step 160 of main flow chart 1. Also, the temperature inside the refrigerator is the pressure [411
If it is determined that the OFF condition is met, step 186
Proceed to and set the new rotation speed Nnew9! Set it to O. As a result, when the compressor is close to stopping and the pressure difference ΔP is smaller than a certain set value B, that is, when the pressure difference ΔP between the suction side and the discharge side of the compressor in the refrigerant circuit is small, the rotation speed of the compressor is reduced. control so that the pressure difference ΔP becomes larger than a certain set value B. As a result, when the compressor 5 is stopped, the pressure difference between the suction side and the discharge side of the compressor 5 is greater than a certain set value B, so the refrigerant flows backward from the 0 section to the D section shown in Fig. 2. It's pressure! 415 is quickly released in large quantities after stopping, but since they are stopped by the check valve 14, the pressure in section D rises rapidly as shown in Fig. 5, and the difference between the pressure value PH and the pressure value PL increases. The differential pressure valve 13 operates when a certain value ΔP = (on the evaporator 11 side), and the state of the refrigerant before the compressor is stopped is maintained. Therefore, the time T required for stabilizing the refrigerant circuit after restart is shortened. In addition, in Fig. 5, Pe is evaporated @
This is the pressure on the discharge side of No. 11. In the above embodiment, the pressure detection elements 8a and 8b are used to detect the pressure difference before and after the compressor, and the set value B where the pressure difference ΔP is
The rotation speed of the compressor 5 was increased only when the
A refrigerator without a pressure sensing element is controlled by this system shown in FIG. FIG. 6 shows a second embodiment of the refrigerator control device according to the present invention. The same reference numerals as in FIG. 1 refer to the same parts, and the differences from FIG. The control means 3A, which sends a command to the operation control means 4 based on the output signal from the set temperature detection means 2, controls the pressure difference ΔP immediately before the pressure tmm is stopped to a large value without using the pressure detection information before and after the compressor. We have made it possible. FIG. 7 is a flowchart 1 showing the operation procedure of the control program of the control means 3A in the second embodiment. In this flowchart 1, steps 110 to 16
0 is the same as the processing steps in FIG. 3 in the first embodiment, so the explanation thereof will be omitted and the different parts will be emphasized. That is, if it is determined in step 140 that the temperature difference -T is smaller than a certain set value A, the process proceeds to step 190, and the current rotational speed NnewIe is changed before the compression e15 is stopped.
Processing is performed to forcibly increase the rotation speed to the maximum rotation speed N1m1131. Then, in the next step 191, it is determined whether the temperature inside the refrigerator is a compressor OFF condition, and if "NO", the process moves to step 160, outputs the rotation speed N new, and performs high rotation operation. If "rYES", the process advances to step 192 and the rotational speed Nnew is set to zero. In this way, when JT<A, the rotational speed of the compressor 5 is forcibly increased to the maximum value Nmix before stopping, thereby increasing the pressure difference JP and eliminating the delay in the operation of the differential pressure valve, and restarting the compressor. Shorten after startup. Therefore, the same effects as those of the first embodiment described above can be achieved at low cost without the need for a pressure detection element. FIG. 8 is an overall system configuration diagram showing a third embodiment of the refrigerator control device according to the present invention. In the figure, the same reference numerals as in FIG. 1 represent the same parts, and the difference from FIG. The configuration is such that an outside air temperature signal from the means 9 is inputted, thereby making it possible to perform the same function as the first embodiment without the need for pressure detection means. Also,
9a is a detection element that detects the outside temperature of the refrigerator 6;
The outside air temperature detected by this element 9a is taken into the outside air temperature detection means 9. FIG. 9 is a flowchart 1 showing the operation procedure of the control program of the control means 3B in the third embodiment. In this flowchart, steps 110 to 16
0 is the same as the processing steps in FIG. 3 in the first embodiment, so the explanation thereof will be omitted and the different parts will be emphasized. That is, in step 140, the temperature difference IU
If it is determined that T is smaller than a certain set value A, the process proceeds to step 200, and it is determined whether the outside air temperature Ta1r is larger or smaller than a certain set value E. Here, when it is determined that Ta1r≧E, the process proceeds to step 150. At this time, since the high-low pressure difference ΔP in the refrigerant circuit is generally large, the compressor is not forced to rotate at high speed before stopping. Furthermore, if it is determined in step 200 that T air<E, the process proceeds to step 210, where the current rotational speed N, new is forcibly increased to the maximum rotational speed Nmax before the compressor 5 is stopped. And next step 2°1
In step 1, it is determined whether the temperature inside the refrigerator is the compressor OFF condition, and r
If NOJ, proceed to step 160 and set the rotation speed N n
It outputs ew and operates at high speed. If it is rYEsJ, the process advances to step 212 and the rotational speed N new is set to zero. In this embodiment, in addition to obtaining the same effects as in the first embodiment, when ΔTEA and Tai≧E,
By stopping forced high-speed rotation before the compressor is stopped, it is possible to reduce power consumption due to unnecessary high-speed rotation, and it is also possible to reduce the running cost of the refrigerator.

【Effect of the invention】

As described above, according to the present invention, the state of the refrigerant circuit after the compressor is stopped can be maintained close to the state before it was stopped.
There is little loss during shutdown, which reduces unnecessary power consumption δ after restart, and the refrigerant condition quickly stabilizes after restart, allowing the temperature inside the refrigerator to quickly return to the state before shutdown. It is possible to improve the preservation of food in the refrigerator.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of a refrigerator control device showing a first embodiment of the present invention, FIG. 2 is a refrigerant circuit diagram thereof, FIG. 3 is a flowchart showing the entire main routine for control, and FIG. Flowchart 1 showing the details of the subroutine of the main part, Figure 5 is a pressure change diagram of each part in the refrigerant circuit,
Fig. 6 is an overall configuration diagram of a refrigerator control device showing a third embodiment of the present invention, Fig. 7 is a flowchart 1 for explaining its operation, and Fig. 8 shows a third embodiment of the invention. The overall configuration of the refrigerator control device, FIG. 9 is the main flowchart 1 for explaining its operation, and FIG. 10 is the conventional refrigerator ff1ll.
#An overall configuration diagram of the device, FIG. 11 is a flowchart 1 showing the operation of FIG. 10. 1.Inner temperature detection means, 1a.Inner temperature detection element, 2.Setting temperature detection means, 2a.Variable resistance type for indoor temperature setting, 3, 3A, 3B.Control means, 4 operations. Control means, 5. Compressor, 6. Refrigerator, 7. Freezer compartment, 8.
・Pressure detection means, 8a, 8b ・Pressure detection element, 9・
...Outside air temperature detection means, 9a...Outside air temperature detection element. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] In a refrigerator control device that is equipped with a differential pressure valve that operates when the compressor is stopped, and that controls the compressor at variable speed according to the difference between the detected temperature inside the refrigerator and the set temperature, the pressure in the refrigerant circuit is A control device for a refrigerator, comprising a control means for changing the rotation speed of a compressor so that the pressure in a high-pressure section becomes equal to or higher than a certain set value.