JPH05346279A - Controller for refrigerating cycle - Google Patents

Abstract

PURPOSE:To always accurately control opening of an electronic expansion valve irrespective of the length of operating time. CONSTITUTION:If a large deviation occurs between an actual opening of an electronic expansion valve 4 and a value of an opening command from opening control means 8, a discharge temperature of a compressor 1 becomes high. Malfunction detecting means 10 outputs a malfunction detection signal if the discharge temperature T0 becomes a predetermined value or higher. Thus, compressor stop instructing means 13 generates a stop command, and compressor control means 15 stops the compressor 1. When a timer 11 measures one minutes after the malfunction is detected, full-closing operation instructing means 14 outputs a full-close command to the means 8. Thus, the valve is fully closed. Then, the means 8 opens the valve to an opening corresponding to a deviation (Te-Ti) of temperatures Te, Ti. When a timer 12 finishes to measure 2min and 20sec, the stop command output from the means 13 is eliminated, and the compressor 1 is restarted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for controlling a refrigeration cycle such as an air conditioner or a refrigerator having an electronic expansion valve.

[0002]

2. Description of the Related Art An expansion valve is incorporated in a refrigerant circuit in order to properly adjust the refrigerant flow rate, but recently, an electronic expansion valve using a pulse motor is often adopted in consideration of the certainty of control. Has been done. This electronic expansion valve changes the valve opening stepwise according to the number of input pulses.

By the way, in the conventional air conditioner and refrigerator, the valve opening degree of the electronic expansion valve is once fully closed every time the power is turned on, and then the valve opening degree is controlled to the valve opening degree commanded. I'm trying to open. This means that the valve opening of the electronic expansion valve at a certain point should originally correspond to the cumulative number of pulses input up to that point, but if the valve is caught during opening / closing operation, the valve will open. Since the correspondence between the degree and the cumulative number of pulses is lost, after a certain amount of operating time, the electronic expansion valve is once fully closed and the valve opening is set to zero. This is because it is necessary to secure the correspondence relationship of.

[0004]

As described above, in the conventional device, the zero adjustment of the electronic expansion valve is performed every time the power is turned on. There is no big difference in the correspondence with numbers.

However, when continuously operated for a long time, the correspondence between the actual valve opening and the number of pulses may be greatly deviated due to the above-mentioned valve catching. In such a case, it becomes impossible to properly control the flow rate of the refrigerant, so that, for example, the refrigerant discharge temperature of the compressor may become abnormally high, or a breakdown of the compressor may occur. ..

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a refrigeration cycle control device capable of always accurately controlling the opening degree of an electronic expansion valve regardless of the operating time. It is a thing.

[0007]

As a means for solving the above problems, a first aspect of the present invention has an electronic expansion valve for adjusting the flow rate of a refrigerant in a refrigerant circuit, and is for detecting the temperature of a predetermined portion of the refrigerant circuit. In a refrigeration cycle control device having an opening control means for controlling the opening of this electronic expansion valve based on
An abnormality detecting means for detecting an abnormal state of the refrigerant circuit, a compressor stop command means for instructing the compressor to stop when the abnormality detecting means detects an abnormality, and an opening state when the abnormality detecting means detects an abnormality. And a setting operation instructing means for instructing a reference position setting operation of the electronic expansion valve to the degree control means.

A second aspect of the present invention is the refrigeration cycle control device according to the first aspect, wherein the setting operation commanding means sets the high pressure side and the low pressure side in the refrigerant circuit after the abnormality detecting means detects an abnormal state. It is characterized in that the reference position setting operation is instructed after a sufficient time has elapsed for the pressure difference with the side to fall below a certain level.

[0009]

In the structure of the first aspect of the present invention, when a large deviation occurs between the actual opening degree of the electronic expansion valve and the opening degree grasped by the opening degree control means, the refrigerant flow rate is properly controlled. As a result, the refrigerant circuit becomes abnormal.

The abnormality detecting means detects this abnormal state. Based on the abnormality detecting signal, the compressor stop command means outputs a compressor stop command to the compressor control means, and the setting operation command means is the opening control means. The reference position setting operation command is output to. As a result, the compressor stops operating and the valve of the electronic expansion valve is driven to the reference position.

After the valve of the electronic expansion valve is driven to the reference position, the opening control means drives the valve of the electronic expansion valve again to the valve opening determined by the temperature detection of the predetermined portion of the refrigerant circuit.

In the configuration of the second aspect of the invention, the reference position setting operation is started after the high pressure side and the low pressure side of the refrigerant circuit are balanced to some extent, rather than immediately performing the fully closing operation when the abnormality detecting means detects the abnormality. I am trying to do it. Therefore, the reference position setting operation is not hindered by the pressure difference between the high pressure side and the low pressure side, and the valve opening degree of the electronic expansion valve can be reliably adjusted to the reference position.

[0013]

Embodiments of the present invention will be described below with reference to FIGS. FIG. 1 is a block diagram showing the configuration of this embodiment.

In FIG. 1, the refrigerant discharged from the compressor 1 is sent to the outdoor heat exchanger 3 through the four-way valve 2. The refrigerant that has undergone heat exchange in the outdoor heat exchanger 3 is the electronic expansion valve 4
It is sent to the outdoor heat exchanger 5 through the passage, is further heat-exchanged there, and is then circulated again through the four-way valve 2 to the suction port of the compressor 1.

On the suction side of the compressor 1 and the inlet side of the indoor heat exchanger 5, the refrigerant temperature sensors 6 and 6, respectively.
7 is attached so that the refrigerant temperatures Ti and Te are output to the opening degree control means 8. Opening control means 8
Controls the opening of the electronic expansion valve 4 on the basis of the deviation (Te-Ti) between the refrigerant temperatures Ti and Te to properly adjust the flow rate of the refrigerant flowing in the refrigerant circuit.

A refrigerant temperature sensor 9 is attached to the discharge side of the compressor 1, and the refrigerant temperature T0 is output to the abnormality detecting means 10. The abnormality detection signal from the abnormality detection means 10 is output to the timers 11 and 12 and the compressor stop command means 13. Timer 11
Is the time T1 (for example, 1 minute) after the abnormality detection signal is input.
After the lapse of time, a signal is output to the full-close operation command means 14 as the setting operation command means.
The reference numeral 2 outputs the signal to the compressor stop command means 13 after a time T2 (for example, 2 minutes and 20 seconds) has elapsed since the abnormality detection signal was input.

The compressor stop command means 13 outputs a compressor stop command to the compressor control means 15 immediately when an abnormality detection signal is input, and when a signal is input from the timer 12, the compressor stop command that has been output until then is output. It is designed to be released immediately.

Next, the operation of the present embodiment thus constructed will be described with reference to the flowchart of FIG.

During normal operation, the opening control means 8 inputs the indoor heat exchanger temperature Te from the refrigerant temperature sensor 7 and the compressor suction temperature Ti from the refrigerant temperature sensor 6 (step 1), and deviates between both temperatures. An opening degree command signal based on (Te-Ti) is output to control the opening degree of the electronic expansion valve 4 (step 2).

On the other hand, the abnormality detecting means 10 inputs the compressor discharge temperature T0 from the refrigerant temperature sensor 9 (step 3) and determines whether or not the temperature T0 exceeds 120 ° C. (step 4).

Although the actual valve opening of the electronic expansion valve 4 should originally match the value of the opening command from the opening control means 8, as described above, inside the electronic expansion valve 4. If you get caught, etc. A large deviation will occur between the actual valve opening and the value of the opening command. When such a deviation occurs, the amount of refrigerant sucked by the compressor 1 becomes insufficient, so that the compressor discharge temperature T0 rapidly rises, and
It will exceed ℃.

Then, the abnormality detection means 10 outputs an abnormality detection signal, and the compressor stop command means 13 outputs a compressor stop command to the compressor control means 15 based on this. Then, the compressor control means 15 stops the operation of the compressor 1 based on the input of this stop command. At this time, the timers 11 and 12 have time T1 and
Start the measurement of T2 (step 5).

When one minute has passed after the abnormality detecting means 10 outputs the abnormality detecting signal, the timer 11 outputs a time-up signal to the fully closing operation instructing means 14 (step 6).
As a result, the fully-closed operation command means 14 outputs a fully-closed operation command, and the opening degree control means 8 fully closes the electronic expansion valve 4 (step 7). Here, the reason why the full-close operation is not started immediately when the abnormality detection means 10 detects an abnormality and the full-close operation is started after waiting for 1 minute is that the high pressure side and the low pressure side in the refrigerant circuit are in between. This is because the pressure difference with the side balances to a certain level or less, so that the fully closing operation is smoothly performed without being hindered, and the valve opening degree can be reliably set to zero.

After the electronic expansion valve 4 is fully closed, the opening control means 8 outputs an opening command to open the valve of the electronic expansion valve 4 again up to the valve opening corresponding to the deviation (Te-Ti). (Step 8). At this time, the actual valve opening of the electronic expansion valve 4 and the value of the opening command should normally be substantially the same.

Next, the timer 12 outputs a time-up signal to the compressor stop command means 13 when 2 minutes and 20 seconds have passed (step 9). As a result, the stop command that has been output from the compressor stop command means 13 until then is no longer output, so the compressor control means 1
5 starts the operation of the compressor 1 again (step 10).

FIG. 3 is a time chart showing the changes in the operating state of the compressor 1 and the state of the valve opening degree of the electronic expansion valve 4 in the above-described operation in comparison.

In this figure, t1 is the abnormality detecting means 10
Is detected, t2 is the start time of the fully-closed operation of the electronic expansion valve 4, t3 is the end time of the fully-closed operation, t4 is the end time of the opening control again, and t5 is the restart time of the compressor 1.

FIG. 4 shows steps 3 and 4 surrounded by a dotted line in the flow chart of FIG.
1 and 12 are replaced.

That is, in the embodiment shown in FIG. 1, it is determined that the compressor 1 is abnormal when the discharge temperature of the compressor 1 is higher than a certain temperature. In this case, however, it is determined that the compressor motor is abnormal when the compressor motor breaks down. It is supposed to do.

In this case, the abnormality detecting means 10 of FIG. 1 inputs the input current I of the compressor motor from a current sensor (not shown) instead of the compressor discharge temperature T0 (step 11), and the input current I is When the set value Is (for example, 20 A) is exceeded, it is determined that there is an abnormality (step 12).

In the above embodiment, the setting operation commanding means is the fully closing operation commanding means, and the position where the valve is fully closed is the reference position. However, the setting operation commanding means is the fully opening operation commanding means. A configuration in which the position where the valve is fully opened may be used as the reference position.

[0032]

As described above, according to the present invention, the means for detecting an abnormality caused by the deviation of the opening of the electronic expansion valve is provided, and when the abnormality is detected, the reference position setting operation is performed each time. Since the valve is thereafter driven to the original position, the opening degree of the electronic expansion valve can always be accurately controlled regardless of the length of the operating time.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an exemplary embodiment of the present invention.

FIG. 2 is a flowchart regarding the operation of FIG.

FIG. 3 is a time chat tote related to the operation of FIG.

FIG. 4 is a flowchart in which a portion surrounded by a dotted line in FIG. 2 is replaced with another step.

[Explanation of symbols]

 1 Compressor 4 Electronic Expansion Valve 8 Opening Control Means 10 Abnormality Detection Means 13 Compressor Stop Command Means 14 Setting Operation Command Means (Fully Closed Operation Command Means) 15 Compressor Control Means

Claims (2)

[Claims] 1. A refrigeration cycle having an electronic expansion valve for adjusting the flow rate of a refrigerant in a refrigerant circuit and opening control means for controlling the opening of the electronic expansion valve based on the temperature detection of a predetermined portion of the refrigerant circuit. In the control device, abnormality detection means for detecting an abnormal state of the refrigerant circuit, compressor stop command means for instructing stop of the compressor when the abnormality detection means detects an abnormality, and when the abnormality detection means detects an abnormality A refrigeration cycle control device, further comprising: a setting operation command means for instructing the opening control means to perform a reference position setting operation of the electronic expansion valve. 2. The refrigeration cycle control device according to claim 1, wherein the setting operation commanding means sets the pressure difference between the high pressure side and the low pressure side in the refrigerant circuit after the abnormality detecting means detects the abnormal state. The refrigeration cycle control device is configured to instruct the reference position setting operation after a lapse of a time sufficient for the temperature to fall below a certain level.