JP2000074504A - Method and apparatus for controlling air conditioner - Google Patents

Abstract

(57) [Summary] [Problem] In superheat control of an air conditioner,
Quickly exits the liquid back state at low compressor speed. SOLUTION: A temperature difference ((SH) amount) between a suction refrigerant temperature of a compressor 1 and a heat exchange temperature of an evaporator is detected at predetermined time intervals, and according to the detected (SH) amount. The degree of opening and closing of the electronic expansion valve 5 constituting the refrigeration cycle is adjusted according to the number of operation pulses, and superheat control is performed so that the (SH) amount matches the target value. At this time, while the rotation speed of the compressor 1 is detected by the rotation speed detecting unit 11a, the detected rotation speed (S
-H) The counter unit 11b detects the number of times that the amount continuously stays within the predetermined range, and only when the rotation speed is low below the predetermined value and the count value reaches the predetermined value, the electronic expansion valve 5 The number of operation pulses for adjusting the pressure is made larger than usual, and the opening and closing of the electronic expansion valve 5 is appropriately adjusted to quickly escape the liquid back state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an expansion valve (electronic expansion valve) constituting a refrigeration cycle of an inverter type air conditioner.
More specifically, the so-called superheat control, which adjusts a temperature difference ((S−H) amount) between a suction refrigerant temperature (suction temperature) of a compressor and a heat exchange temperature of an evaporator to a target value. The present invention relates to a method and a device for controlling an air conditioner for performing the above.

[0002]

2. Description of the Related Art As shown in FIG. 4, for example, this air conditioner has a refrigeration cycle including a compressor 1, a four-way valve 2, an indoor heat exchanger 3, an outdoor heat exchanger 4, an electronic expansion valve 5, and the like. . During the cooling operation, the refrigerant is switched from the indoor heat exchanger 3 to the compressor 1 by switching the four-way valve 2 according to the dashed arrow in FIG. 4 and further from the compressor 1 to the indoor heat exchanger 4 via the outdoor heat exchanger 4 and the electronic expansion valve 5. While returning to the exchanger 3, the indoor fan is controlled to rotate according to the set air volume of the remote controller, etc., and the cool air exchanged by the indoor heat exchanger 3 is blown into the room. The compressor 1 is operated at the predetermined operating frequency to control the room temperature.

[0003] During the heating operation, the refrigerant is transferred from the outdoor heat exchanger 4 to the compressor 1, and from the compressor 1 to the outdoor heat exchanger 4 via the indoor heat exchanger 3 and the electronic expansion valve 5, contrary to the cooling operation. On the other hand (see the solid arrow in FIG. 4), the rotation of the indoor fan is controlled in accordance with the set air volume of the remote controller and the like, and the hot air exchanged by the indoor heat exchanger 3 is blown into the room. The compressor 1 is operated at a predetermined operating frequency according to the difference between the two to control the room temperature.

For this purpose, as shown in FIG. 5, the air conditioner includes an indoor unit control unit 6 and an outdoor unit control unit 7 including a microcomputer, a drive circuit, and the like. Along with controlling the indoor fan, a predetermined command (such as an operating frequency corresponding to the difference between the room temperature and the set value) is transferred to the outdoor unit control unit 7, and the outdoor unit control unit 7 controls the compressor 1 and the like based on the command.

[0005] The air conditioner also includes an indoor heat exchanger 3.
Indoor heat exchange thermistor 8 to detect heat exchange temperature of the compressor 1
And an outdoor heat exchange thermistor 10 for detecting the heat exchange temperature of the outdoor heat exchanger 4. Then, in the outdoor unit control unit 7, the difference ((SH) amount) between the suction temperature of the compressor 1 and the temperature (heat exchange temperature) of the evaporator is set to a constant value (target value; for example, 5 deg.). Is performed, that is, the degree of opening and closing of the electronic expansion valve 5 is adjusted to a predetermined value,
Stabilize the refrigeration cycle.

For example, the (S−H) amount is detected every minute,
The electronic expansion valve 5 is driven in accordance with the difference between the (SH) amount and the target value (5 deg.), And the degree of opening and closing of the electronic expansion valve 5 is adjusted. In this case, it is determined whether the (SH) amount is within the range shown in Table 1 below, and the number of operating pulses of the electronic expansion valve 5 is determined.

[0007]

[Table 1]

As is clear from Table 1, as the (SH) amount falls below or exceeds the target value (5 deg.), The number of operating pulses increases, that is, the operation according to the (SH) amount. The number of pulses changes, and the degree of opening and closing of the electronic expansion valve 5 can be appropriately adjusted.

[0009]

However, in the control method of the air conditioner, when the rotational speed of the compressor 1 is low (for example, 50 rps), the pressure loss is inevitably small and the (SH) amount is set to a target value. The value (5 deg.) Does not readily approach, and as shown in FIG. 6, it takes time for the (SH) amount to reach the target value. As a result, the liquid-back state continues for a long time, which not only causes an increase in the load on the compressor 1 but also takes time until the electronic expansion valve 5 has an appropriate throttle amount, and also from the viewpoint of energy saving. Not preferred.

That is, when the compressor 1 has a low rotation speed, the (SH) amount is -2 de because the pressure loss is small.
g. Higher, that is, the (SH) amount is as shown in Table 1 above.
Not only falls to the range of 2 ≦ SH amount <2,
Since the number of operating pulses of the electronic expansion valve 5 is set to a low value in order to prevent hunting in the superheat control,
The number of operation pulses in the range of 2 ≦ SH amount <2 is as small as −2 pulses, and thus the throttle of the electronic expansion valve 5 is insufficient.
This is because the refrigerant in the liquid state returns to the compressor 1, and the state continues for a long time.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to quickly escape a liquid back state at a low rotational speed of a compressor, reduce a load on the compressor, and improve reliability. Another object of the present invention is to provide an air conditioner control method and an apparatus thereof that contribute to energy saving.

[0012]

SUMMARY OF THE INVENTION To achieve the above object, the present invention provides a temperature difference ((SH) amount) between a refrigerant suction temperature of a compressor constituting a refrigeration cycle and a heat exchange temperature of an evaporator.
Is detected at predetermined time intervals, and the degree of opening and closing of an expansion valve constituting the refrigeration cycle is adjusted by the number of operation pulses corresponding to the detected (SH) amount, and the (SH) amount is set to a target value. In the control method for an air conditioner that performs superheat control so as to match, the number of revolutions of the compressor is as low as a predetermined value or less, and the detected (S−H) amount stays within a predetermined range continuously for a predetermined number of times. The number of operating pulses for adjusting the electronic expansion valve is set to be larger than normal only when the electronic expansion valve is operated.

In this case, the predetermined range is at least-
2 deg. With the above, +2 deg. A smaller range is preferred.

According to the present invention, the temperature difference ((S) between the refrigerant suction temperature of the compressor constituting the refrigeration cycle and the heat exchange temperature of the evaporator is determined.
-H) amount is detected at predetermined time intervals, and the degree of opening and closing of the expansion valve constituting the refrigeration cycle is adjusted by the number of operation pulses corresponding to the detected (SH) amount, and the (S-
H) In a control device for an air conditioner that performs superheat control so as to adjust the amount to a target value, a rotation number detecting means for detecting a rotation number of the compressor;
H) a counter that counts the number of times that the amount is within a predetermined range and resets when the amount falls outside the predetermined range; and a counter that resets the number of rotations below a predetermined value and the value of the counter reaches a predetermined value. Operating pulse changing means for changing the number of operating pulses to a value larger than that of a normal operation pulse.

In this case, the predetermined range is at least-
2 deg. With the above, +2 deg. A smaller range is preferred.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In FIG. 1, FIG.
The same parts as those described above are denoted by the same reference numerals, and redundant description will be omitted.
See FIG. 4 for the refrigeration cycle. For the superheat control, see Table 1 above.

According to the control method of the air conditioner of the present invention, the rotational speed of the compressor is low and the superheat amount ((SH))
When the amount is a predetermined range (for example, −2 ≦ (SH) <in Table 1)
When the number of operation pulses of the electronic expansion valve is increased only when the state remains in 2), the degree of opening and closing of the electronic expansion valve changes greatly, and attention is paid to the fact that the electronic expansion valve can quickly escape from the liquid back state.

Therefore, as shown in FIG. 1, in addition to the function of the outdoor unit control section 7 shown in FIG.
And a superheat amount ((SH) amount) detected every predetermined time continuously within a predetermined range (eg, −2 ≦ (SH) amount <2). Counter section 11b for counting the number of times that
When the rotation speed is equal to or less than a predetermined value (for example, 50 rps),
Only when the count value reaches a predetermined value (for example, five times), the number of operating pulses of the electronic expansion valve 5 in the case of −2 ≦ (SH) amount <2 is changed from −2 pulses to −10 pulses. An outdoor unit control unit 11 having an operation pulse changing unit 11c is provided. It should be noted that the rotation speed detection unit 11a and the counter unit 11
b and the operation pulse changing unit 11c can be realized by a microcomputer of the outdoor unit control unit 11.

Next, the operation of the control device for an air conditioner having the above configuration will be described with reference to the flow chart of FIG. 2 and the time chart of FIG.

First, when an operation is performed by the remote controller, the indoor unit control unit 6 transfers a signal (operation frequency or the like) necessary for adjusting the room temperature to the outdoor unit control unit 11. The outdoor unit control unit 11 drives at least the compressor 1 to a predetermined degree, sets the electronic expansion valve 5 to a predetermined opening degree, and operates a refrigeration cycle. Note that, similarly to the conventional case, the indoor unit control unit 6 and the outdoor unit control unit 1
1 performs room temperature adjustment by performing other necessary controls (such as fan rotation control).

In this case, in the heating operation, the outdoor unit control section 11 detects a temperature difference ((SH) amount) between the outdoor heat exchange temperature and the suction temperature, and determines this (SH) amount. Based on Table 1, the number of operating pulses of the electronic expansion valve 5 is determined from Table 1, and the degree of opening and closing of the electronic expansion valve 5 is adjusted with the determined number of operating pulses to set the (SH) amount to the target value (5 deg.). Perform super heat control to match.

In the cooling operation, the indoor unit control unit 6
Transfers the indoor heat exchange temperature to the outdoor unit control unit 11, and the outdoor unit control unit 11 detects the temperature difference ((SH) amount) between the suction temperature (suction temperature) of the compressor 1 and the indoor heat exchange temperature. I do.

At this time, the outdoor unit controller 11 controls the compressor 1
And the (S−H) amount is detected (step ST1). It is determined whether or not this rotation speed is 50 rps or less (when the maximum rotation speed of the compressor is 120 rps) and the current (SH) amount is at least within a range of -2 ≦ SH <2. (Step ST2). In step ST2, the (SH) amount is -2de
g. With the above, 0 deg. The following range (-2 ≦ SH ≦
0) may be determined.

When the rotational speed of the compressor 1 is as low as 50 rps or less and the (SH) amount is within a range of -2≤SH <2, the counter 11b is incremented (+
1) (Step ST3), it is determined whether or not the count value of the counter section 11b has reached 5 (Step ST4).

If the value of the counter section 11b has not reached 5, the process proceeds to step ST5, waits for a predetermined time (for example, one minute), returns to step ST1 after one minute has elapsed, and repeats the above-described steps. That is, the superheat control is performed every predetermined time.

When the rotation speed of the compressor 1 is as low as 50 rps or less, the (SH) amount remains in the range of -2≤SH <2, and the value of the counter 11b reaches 5, That is, even if the superheat control is executed five times, the rotation speed is continuously low at 50 rps or less, and the (SH) amount is continuously in the range of −2 ≦ SH <2. When,
The operation pulse changing unit 11c changes the number of operation pulses from -2 to -1.
At the same time, the counter section 11a is cleared once (step ST6).

Then, it is detected in step ST1 (S-
H) When performing superheat control based on the amount,
Since the number of operation pulses is -10 which is larger than the normal value shown in Table 1, the throttle of the electronic expansion valve 5 is increased, and the (SH) amount is increased (see the dashed arrow A in FIG. 3).

Then, the counter section 11b sets the step ST
6, the above-described processing is repeated, and the rotational speed of the compressor 1 becomes 50 rpm again.
s or less, and the (SH) amount remains in the range of −2 ≦ SH <2, and the value of the counter unit 11b becomes 5 again.
, The number of operation pulses is changed from −2 to −10,
The throttle of the electronic expansion valve is increased (see the dashed arrow B in FIG. 3).

If the rotational speed of the compressor 1 is higher than 50 rps or the (SH) amount is out of the range of 2 ≦ SH <2, the liquid back state is extremely small. The process proceeds to ST7, where the counter 11a is cleared, and the above-described processing is repeated, that is, the process returns to the normal superheat control.

As described above, the rotation speed of the compressor 1 is 50 rpm
s, and the number of operation pulses of the electronic expansion valve 5 is as small as −2, the throttle of the electronic expansion valve 5 is small, and the liquid falls back. However, by changing the number of operation pulses to a large value, Since the adjustment of the degree of opening and closing of the electronic expansion valve 5 can be increased, the liquid back state can be quickly removed.

Further, the rotation speed detector 11a of the above-described embodiment,
The counter unit 11b and the operation pulse changing unit 11c can be realized by a microcomputer that is a control unit of the air conditioner, that is, there is no need to add new hardware and the cost does not increase.

[0032]

As described above, according to the control method of the air conditioner and the apparatus according to the first aspect of the present invention, the temperature of the suction refrigerant of the compressor and the heat exchange temperature of the evaporator constituting the refrigeration cycle are determined. The temperature difference ((S−H) amount) is detected at predetermined time intervals, and the degree of opening and closing of the expansion valve constituting the refrigeration cycle is adjusted by the number of operation pulses according to the detected (S−H) amount, In the method for controlling an air conditioner that performs superheat control so that the (SH) amount is adjusted to a target value, the number of revolutions of the compressor is as low as a predetermined value or less;
Only when the detected (SH) amount stays within a predetermined range continuously for a predetermined number of times, the number of operation pulses for adjusting the electronic expansion valve is set to be larger than the normal time. You can change the number to a larger value,
In other words, since the degree of opening and closing of the electronic expansion valve can be increased, the liquid back state can be quickly removed, the load on the compressor can be reduced, reliability can be improved, and energy can be saved. effective.

According to a second aspect of the present invention, in the first aspect, the predetermined range is at least -2 deg. With the above, +2 deg. Claim 1 because it is a smaller range
In addition to the effect of -2 deg. ≦ S−H <+2 deg. The number of operation pulses in the range of
In addition, since it is easy to fall into the liquid back state when it is within the range, by limiting to the range, there is an effect that the liquid back state can be effectively escaped.

According to the third aspect of the present invention, the temperature difference ((SH) amount) between the suction refrigerant temperature of the compressor constituting the refrigeration cycle and the heat exchange temperature of the evaporator is detected at predetermined time intervals. The degree of opening and closing of the expansion valve constituting the refrigeration cycle is adjusted by the number of operation pulses corresponding to the detected (SH) amount, and superheat control is performed so that the (SH) amount is adjusted to a target value. In the control device for the air conditioner, a rotation speed detecting means for detecting a rotation speed of the compressor, a number of times the detected (SH) amount is within a predetermined range, and counting the number of times that the detected (SH) amount falls outside the predetermined range. A counter which resets when the number of rotations is equal to or less than a predetermined value, and an operation pulse changing unit which changes the number of operation pulses to a value larger than a normal time only when the value of the counter reaches a predetermined value. Of When the number of operations is low and the number of operation pulses is continuously small, the number of operation pulses can be changed to a large value, that is, the degree of opening and closing of the electronic expansion valve can be increased. The state can be quickly released, the load on the compressor can be reduced, reliability can be improved, and energy can be saved. Further, since the rotation speed detecting means, the counter and the operation pulse changing means can be realized by a microcomputer which is a control means of the air conditioner, it is not necessary to add new hardware, and the cost does not increase. This has the effect of requiring only a short time.

According to the invention described in claim 4, in claim 3, the predetermined range is at least -2 deg. With the above, +2 deg. Claim 3 because of the smaller range
In addition to the effect of -2 deg. ≦ S−H <+2 deg. The number of operation pulses in the range of
In addition, since it is easy to fall into the liquid back state when it is within the range, by limiting to the range, there is an effect that the liquid back state can be effectively escaped.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram of a control device according to an embodiment of the present invention, to which an air conditioner control method is applied;

FIG. 2 is a schematic flowchart for explaining the operation of the control device shown in FIG. 1;

FIG. 3 is a schematic time chart for explaining the operation of the control device shown in FIG. 1;

FIG. 4 is a schematic configuration diagram for explaining a refrigeration cycle of the air conditioner.

FIG. 5 is a schematic block diagram for explaining a conventional control device for an air conditioner.

FIG. 6 is a schematic time chart for explaining the operation of the control device shown in FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor 3 Indoor heat exchanger 4 Outdoor heat exchanger 5 Expansion valve (electronic expansion valve) 6 Indoor unit control part 7, 11 Outdoor unit control part 8 Indoor heat exchange thermistor 9 Suction thermistor (Compressor suction temperature sensor) 10 Outdoor Heat exchange thermistor 11a Rotation speed detector 11b Counter 11c Operation pulse changer

Claims (4)

[Claims] 1. A temperature difference ((SH) amount) between a suction refrigerant temperature of a compressor constituting a refrigeration cycle and a heat exchange temperature of an evaporator.
Is detected at predetermined time intervals, and the degree of opening and closing of an expansion valve constituting the refrigeration cycle is adjusted by the number of operation pulses corresponding to the detected (SH) amount, and the (SH) amount is set to a target value. In the control method for an air conditioner that performs superheat control so as to match, the number of revolutions of the compressor is as low as a predetermined value or less, and the detected (S−H) amount stays within a predetermined range continuously for a predetermined number of times. The control method of an air conditioner, wherein the number of operation pulses for adjusting the electronic expansion valve is made larger than usual only when the electronic expansion valve is operated. 2. The predetermined range is at least -2 de.
g. With the above, +2 deg. The control method for the air conditioner according to claim 1, wherein the range is smaller than the range. 3. A temperature difference ((S−H) amount) between a suction refrigerant temperature of a compressor constituting a refrigeration cycle and a heat exchange temperature of an evaporator.
Is detected at predetermined time intervals, and the degree of opening and closing of an expansion valve constituting the refrigeration cycle is adjusted by the number of operation pulses corresponding to the detected (SH) amount, and the (SH) amount is set to a target value. In a control device of an air conditioner performing super heat control so as to match, a rotation speed detecting means for detecting a rotation speed of the compressor, and counting the number of times the detected (SH) amount is within a predetermined range. A counter that resets when the rotation speed is out of the predetermined range, and changes the number of operation pulses to a value larger than a normal time only when the rotation speed is equal to or less than a predetermined value and the value of the counter reaches a predetermined value. A control device for an air conditioner, comprising: an operation pulse changing unit that performs the operation. 4. The predetermined range is at least −2 de.
g. With the above, +2 deg. The control method for an air conditioner according to claim 3, wherein the range is smaller.