JP2016183824A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that in an air conditioner for correcting a suspension condition, every time stop control of a compressor is executed, since the compressor cannot be operated at a high frequency, it may be impossible to execute operation according to operation setting.SOLUTION: An air conditioner, when stop control of a compressor is executed and the compressor stops (S8), corrects a suspension condition so that the suspension condition is more severe than that before the compressor stops (S10), and after the suspension condition is corrected, when the corrected condition satisfies a predetermined release condition (S12: YES), releases correction of the suspension condition (S13).SELECTED DRAWING: Figure 3

Description

  The present invention relates to an air conditioner provided with a high-pressure protection means for a compressor.

  Conventionally, an air conditioner provided with a high-pressure protection means for a compressor is known. For example, in Patent Document 1, a high pressure switch (HPS) is attached to the discharge side of the compressor, and when the refrigerant pressure detected by the high pressure switch reaches a predetermined pressure, the operation of the compressor is temporarily stopped. What performs stop control to perform is known. In this air conditioner, the operation of the compressor is stopped, and after a predetermined time has elapsed, the operation of the compressor is restarted to prevent the refrigerant pressure from excessively rising.

  Also, in the air conditioner that performs stop control of the compressor as described above, as another high-pressure protection means, for example, every time the compressor supply current value reaches a predetermined drooping condition value, the frequency of the compressor There is also known one that performs drooping control that lowers.

JP-A-10-132406

  As described above, in the air conditioner in which the compressor stop control and the droop control are performed, if the stop of the compressor is repeatedly stopped by the stop control, the operation time of the compressor is shortened, so that the operation efficiency is lowered. To do. Accordingly, it is conceivable that correction is performed to reduce the drooping condition value each time the compressor stop control is executed, thereby reducing the frequency of the compressor operation stop and improving the operation efficiency. However, if the drooping condition value is corrected, the compressor cannot be operated at a high frequency, so there is a possibility that the operation according to the operation setting (operation requested by the user) cannot be performed.

  Then, the objective of this invention is providing the air conditioner which can perform the driving | operation according to driving | running setting, after drooping conditions are correct | amended.

  An air conditioner according to a first aspect of the present invention includes a refrigerant circuit in which a compressor, a condenser, an expansion valve, and an evaporator are connected, and a control unit that controls the compressor. The control unit has a predetermined refrigerant pressure. When the pressure is reached, stop control for stopping the compressor, and droop control for reducing the frequency of the compressor when a predetermined droop condition is satisfied, in the droop control, When the stop control is executed and the compressor is stopped, the droop condition is corrected so that the droop condition becomes stricter than before the compressor stops, and after the droop condition is corrected Then, when a predetermined release condition is satisfied, the drooping condition correction is returned.

  In this air conditioner, when the predetermined release condition is satisfied after the drooping condition is corrected, the correction of the drooping condition is returned, so that after the predetermined release condition is satisfied (the refrigerant pressure reaches the predetermined pressure) After a difficult operating condition), the compressor can be operated at a high frequency. Therefore, after the drooping condition is corrected, the operation according to the operation setting can be executed.

An air conditioner according to a second invention is the air conditioner according to the first invention, wherein the predetermined release condition is that any one of conditions (1) to (3) is satisfied. .
Condition (1): When a predetermined time has elapsed since the correction of the drooping condition was executed. Condition (2): When the operation of the air conditioner was stopped. Condition (3): When changed to another operation mode.

  In this air conditioner, the predetermined release condition is any one of the conditions (1) to (3), that is, a condition in which it is possible to determine that the refrigerant pressure is in an operating state in which the refrigerant pressure does not easily reach the predetermined pressure. It is possible to prevent stop control from being executed immediately after the return of.

An air conditioner according to a third invention is the air conditioner according to the first invention, wherein the predetermined release condition satisfies the condition (1) and satisfies the condition (2) or (3). It is characterized by being.
Condition (1): When a predetermined time has elapsed since the correction of the drooping condition was executed. Condition (2): When the operation of the air conditioner was stopped. Condition (3): When changed to another operation mode.

  For example, immediately after the droop condition correction is executed, when the droop condition correction is returned when the operation of the air conditioner is stopped or changed to another operation mode, the refrigerant pressure is high. However, since the correction of the drooping condition is returned, the stop control may be immediately executed when the operation of the air conditioner is started or the operation mode is restored. In this regard, in this air conditioner, the drooping condition correction is not returned until a predetermined time has elapsed after the drooping condition correction has been executed, so the stop control is performed immediately after the drooping condition correction is restored. It is easier to prevent it from being executed.

  An air conditioner according to a fourth invention is the air conditioner according to any one of the first to third inventions, wherein the predetermined drooping condition is determined based on a temperature of the condenser. To do.

  In this air conditioner, since the predetermined drooping condition is determined based on the temperature of the condenser suitable for conversion into the refrigerant pressure, drooping control can be executed efficiently.

  As described above, according to the present invention, the following effects can be obtained.

  In the first invention, when the predetermined release condition is satisfied after the drooping condition is corrected, the correction of the drooping condition is returned. Therefore, when the predetermined release condition is satisfied, the refrigerant pressure reaches the predetermined pressure. After a difficult operating condition), the compressor can be operated at a high frequency. Therefore, after the drooping condition is corrected, the operation according to the operation setting can be executed.

  In the second invention, the predetermined release condition is any one of the conditions (1) to (3), that is, a condition in which it is possible to determine that the refrigerant pressure is in an operating state in which the refrigerant pressure does not easily reach the predetermined pressure. It is possible to prevent stop control from being executed immediately after the return of.

  In the third aspect of the invention, since the drooping condition correction is not returned until a predetermined time has elapsed after the drooping condition correction is executed, the stop control is executed immediately after the drooping condition correction is restored. It is easier to prevent this.

  In the fourth aspect of the invention, since the predetermined drooping condition is determined based on the condenser temperature suitable for conversion into the refrigerant pressure, the drooping control can be executed efficiently.

It is a circuit diagram which shows the refrigerant circuit of the air conditioner which concerns on embodiment of this invention. It is a block diagram of the outdoor control part of the outdoor unit shown in FIG. It is a flowchart which shows operation | movement of an air conditioner.

  Hereinafter, an air conditioner according to an embodiment of the present invention will be described with reference to the drawings.

[Configuration of air conditioner]
As shown in FIG. 1, the air conditioner 1 of this embodiment has the indoor unit 2 installed indoors, and the outdoor unit 3 installed outdoor. The air conditioner 1 has a refrigerant circuit in which a compressor 10, a four-way valve 11, an outdoor heat exchanger 12, an expansion valve (decompression mechanism) 13, and an indoor heat exchanger 14 are connected. In the refrigerant circuit, an outdoor heat exchanger 12 is connected to the discharge port of the compressor 10 via a four-way valve 11, and an expansion valve 13 is connected to the outdoor heat exchanger 12. One end of the indoor heat exchanger 14 is connected to the expansion valve 13, and the suction port of the compressor 10 is connected to the other end of the indoor heat exchanger 14 via the four-way valve 11. The indoor unit 2 is provided with an indoor fan (cross flow fan) 15 disposed so as to face the indoor heat exchanger 14, and the outdoor unit 3 is disposed so as to face the outdoor heat exchanger 12. An outdoor fan (propeller fan) 16 is arranged.

  The air conditioner 1 can be operated in a cooling operation, a heating operation, a dehumidifying operation, a humidifying operation, and the like, and any one of the operations is selected and started by an indoor control unit (not shown) arranged in the indoor unit 2. Operation can be performed, operation switching operation and operation stop operation can be performed.

  In the cooling operation and the dehumidifying operation, the refrigerant discharged from the compressor 10 sequentially flows from the four-way valve 11 to the outdoor heat exchanger 12, the expansion valve 13, and the indoor heat exchanger 14 as indicated by the solid line arrows in the figure. A cooling cycle or a dehumidification cycle is formed in which the refrigerant having passed through the exchanger 14 returns to the compressor 10 through the four-way valve 11. That is, the outdoor heat exchanger 12 functions as a condenser and the indoor heat exchanger 14 functions as an evaporator.

  On the other hand, in the heating operation, when the four-way valve 11 is switched, the refrigerant discharged from the compressor 10 is transferred from the four-way valve 11 to the indoor heat exchanger 14, the expansion valve 13, and the outdoor heat exchanger as indicated by broken arrows in the figure. A heating cycle is formed in which the refrigerant flows in sequence to 12 and the refrigerant that has passed through the outdoor heat exchanger 12 returns to the compressor 10 through the four-way valve 11. That is, the indoor heat exchanger 14 functions as a condenser, and the outdoor heat exchanger 12 functions as an evaporator.

  The outdoor unit 3 includes a high pressure switch 21 (HPS) that is a high pressure sensor and an outdoor heat exchanger temperature detection sensor 22 that detects the temperature of the outdoor heat exchanger 12. The high pressure switch 21 is arranged on the discharge side of the compressor 10. The high-pressure pressure switch 21 and the outdoor heat exchanger temperature detection sensor 22 are connected to the outdoor control unit (control means) 30 disposed in the outdoor unit 3 together with the compressor 10, the four-way valve 11, the expansion valve 13, and the outdoor fan 16. It is connected.

  The outdoor control unit (control means) 30 includes a ROM that stores control programs and data for various operations related to the outdoor unit 3 (air conditioner 1), and operations of each unit of the outdoor unit 3 (air conditioner 1). Members such as a CPU that executes various calculations to generate a signal to be controlled, and a RAM that temporarily stores data such as various settings and calculation results of the CPU are included. As shown in FIG. 2, a stop control unit 31, a droop control unit 32, a correction unit 33, a release unit 34, a timer unit 35, and a storage unit 36 are formed by these various members and software.

  The outdoor control unit 30 controls the frequency of the compressor 10 based on an operation setting (for example, a set temperature), and executes an operation that satisfies the user's request. By the way, for example, when the cooling operation is performed in an area where the outside air temperature is high, since the operation is performed at a pressure close to the design pressure, high pressure protection of the compressor 10 is necessary. Therefore, in the outdoor control unit 30, the stop control unit 31, the drooping control unit 32, the correction unit 33, the release unit 34, the timer unit 35, and the storage unit 36 are respectively in cooling operation (including dehumidification operation). The control described below is executed to protect the compressor 10 from high pressure.

  The stop control unit 31 performs stop control to stop the compressor 10 when the discharge refrigerant pressure of the compressor 10 detected by the high pressure switch 21 reaches a predetermined pressure. When the compressor 10 is stopped, the operation of the compressor 10 is resumed after a predetermined time (for example, 3 minutes) has elapsed. Thereby, it is prevented that the discharge refrigerant pressure of the compressor 10 increases excessively.

  The drooping control unit 32 executes drooping control for reducing the frequency of the compressor 10 when a predetermined drooping condition is satisfied. In the present embodiment, the predetermined drooping condition is determined based on the temperature of the outdoor heat exchanger 12 that functions as a condenser during the cooling operation. Specifically, the drooping control is executed when the temperature of the outdoor heat exchanger 12 detected by the outdoor heat exchanger temperature detection sensor 22 exceeds a predetermined drooping condition value (for example, 60 ° C.). Since the temperature of the outdoor heat exchanger 12 functioning as a condenser is suitable for conversion into discharged refrigerant pressure, drooping control can be executed efficiently.

  When the stop control is executed and the compressor 10 is stopped, the correction unit 33 corrects the drooping condition so that the drooping condition becomes stricter than before the compressor 10 stops. Specifically, each time the stop control is executed, the predetermined drooping condition value is decreased by 1 ° C. Therefore, the correction amount of the drooping condition increases according to the number of times that the stop control is executed. For example, when the number of stop controls is 0, the predetermined drooping condition value is 60 ° C., but each time the number of stop controls increases to 1, 2, 3,. , 57 ° C. Note that the count of the number of stop controls is cleared, for example, when a predetermined release condition described later is satisfied. In the air conditioner 1, the maximum correction value is set, and when the correction amount is the maximum value, the correction amount does not change even when the stop control is executed and the compressor 10 is stopped.

  In the air conditioner 1, a predetermined drooping condition value (for example, 60 ° C.) is determined so that the drooping control is performed before the stop control of the compressor 10 is performed. However, depending on the operating condition, before the temperature of the outdoor heat exchanger 12 reaches a predetermined drooping condition value, the discharge refrigerant pressure of the compressor 10 reaches a predetermined pressure and the stop control of the compressor 10 is executed. Can happen. As a result, the driving time of the compressor 10 is shortened and the operation efficiency is lowered. Therefore, in this air conditioner 1, each time the compressor 10 is stopped, the drooping condition value is reduced, thereby suppressing the stop control from being executed earlier than the drooping control.

After the drooping condition is corrected, the canceling unit 34 executes canceling control for returning the drooping condition correction to the original when the predetermined canceling condition is satisfied. Here, the predetermined release condition is to satisfy the following condition (1) and satisfy the condition (2) or the condition (3). As a result, the compressor can be operated at a high frequency after the operation state in which the refrigerant pressure does not easily reach the predetermined pressure, and the operation according to the operation setting can be performed after the drooping condition is corrected.
Condition (1): When a predetermined time (for example, 1 hour) has elapsed since the correction of the drooping condition has been executed Condition (2): When the operation of the air conditioner is stopped Condition (3): From the cooling operation to another When changed to operation mode

  The timer unit 35 measures a predetermined time after the stop control is executed and a predetermined time after the drooping condition is corrected. The storage unit 36 stores the current number of stop controls and the drooping condition value.

  Next, the operation of the air conditioner 1 will be described with reference to FIG.

  First, it is determined whether or not the cooling operation is being performed (including the dehumidifying operation) (S1). When the cooling operation is not being performed (S1: No), step S1 is repeated. On the other hand, when the cooling operation is being performed (S1: Yes), it is determined whether or not the compressor 10 is stopped (S2). When the compressor 10 is stopped (S2: Yes), it is determined whether or not a predetermined time has elapsed since the stop control of the compressor 10 was executed (S3). If the predetermined time has not elapsed (S3: No), the process returns to step S1. When the predetermined time has elapsed (S3: Yes), the operation of the compressor 10 is resumed (S4).

  When the compressor 10 is not stopped (S2: No), it is determined whether the temperature of the outdoor heat exchanger 12 satisfies the drooping condition (S5). When the droop condition is satisfied (S5: Yes), the frequency of the compressor 10 is lowered. When the drooping condition is not satisfied (S5: No), the process proceeds to step S7.

  In step S7, it is determined whether or not the refrigerant pressure on the discharge side of the compressor 10 is equal to or higher than a predetermined pressure. When the refrigerant pressure is equal to or higher than the predetermined pressure (S7: Yes), the compressor is stopped (S8). Then, it is determined whether or not the drooping condition correction value is MAX (predetermined maximum value) (S9). If the drooping condition correction value is MAX (S9: Yes), the drooping condition correction value remains MAX (predetermined maximum value), and if the drooping condition correction value is not MAX (S9: No), compression is performed. The drooping condition is corrected so that the drooping condition becomes stricter than before the machine 10 stops (S10).

  On the other hand, when the refrigerant pressure is less than the predetermined pressure (S7: No), it is determined whether or not the drooping condition is being corrected (S11). When the drooping condition is being corrected (S11: Yes), it is determined whether the release condition is satisfied (S12). On the other hand, when the drooping condition is not being corrected (S11: No), the process returns to step S1. When the release condition is satisfied (S12: Yes), the correction is canceled and the drooping condition is returned to the predetermined drooping condition value (S13). On the other hand, when the release condition is not satisfied (S12: No), the process returns to step S1.

<Characteristics of the air conditioner of this embodiment>
The air conditioner 1 of this embodiment has the following characteristics.

  In the air conditioner 1 according to the present embodiment, when the predetermined release condition is satisfied after the drooping condition is corrected, the drooping condition correction is returned. The compressor 10 can be operated at a high frequency after an operating condition in which it is difficult to reach the predetermined pressure. Therefore, after the drooping condition is corrected, the operation according to the operation setting can be executed.

  In addition, for example, when the droop condition correction is returned when the operation of the air conditioner is stopped or changed to another operation mode immediately after the droop condition correction is performed, the refrigerant pressure is high. However, since the drooping condition is corrected, the stop control may be immediately executed when the operation of the air conditioner is started or the operation mode is restored. In this regard, in the air conditioner 1 of the present embodiment, since the correction of the drooping condition is not returned until the predetermined time has elapsed after the correction of the drooping condition is performed, immediately after the correction of the drooping condition is restored. It is possible to prevent the stop control from being executed.

  Moreover, in the air conditioner 1 of this embodiment, since predetermined drooping conditions are determined based on the temperature of the outdoor heat exchanger 12 suitable for conversion into refrigerant pressure, drooping control can be executed efficiently.

  As mentioned above, although embodiment of this invention was described, it should be thought that the specific structure of this invention is not limited to the said embodiment. The scope of the present invention is shown not only by the description of the above-described embodiment but also by the scope of claims for patent, and further includes meanings equivalent to the scope of claims for patent and all modifications within the scope.

In the above-described embodiment, the case where the predetermined release condition satisfies the condition (1) and the condition (2) or (3) has been described. However, the predetermined release condition is the condition (1). )-It may be that any one of the conditions (3) is satisfied.
Condition (1): When a predetermined time (for example, 1 hour) has elapsed since the correction of the drooping condition has been executed Condition (2): When the operation of the air conditioner is stopped Condition (3): From the cooling operation to another When changed to operation mode

  As a result, the predetermined release condition is any one of the conditions (1) to (3), that is, a condition in which it is possible to determine that the refrigerant pressure is in an operation state in which the refrigerant pressure does not easily reach the predetermined pressure, and thus the drooping condition correction is returned. After that, stop control can be prevented from being executed immediately. Note that the predetermined release condition may be other than these.

  In the above-described embodiment, the case where the drooping condition is determined based on the temperature of the outdoor heat exchanger 12 has been described. However, the drooping condition may be determined based on the discharge pipe temperature of the compressor 10, or the compressor It may be determined based on 10 supply current values. Specifically, the drooping control may be executed when the discharge pipe temperature of the compressor 10 reaches a predetermined drooping condition value, or the supply current value of the compressor 10 reaches a predetermined drooping condition value. In this case, the drooping control may be executed.

  Further, in the above-described embodiment, the case where the correction is restored (cancelled) when a predetermined cancellation condition is satisfied has been described. However, if the drooping condition is relaxed compared to before the compressor is stopped. , It is not always necessary to put it back.

  Moreover, although the above-mentioned embodiment demonstrated the case where this invention was applied at the time of air_conditionaing | cooling operation, you may apply this invention at the time of heating operation. In that case, the predetermined drooping condition is determined based on, for example, the indoor heat exchanger 14 that functions as a condenser during heating operation.

  If the present invention is used, after the drooping condition is corrected, an operation according to the operation setting can be executed.

1 Air conditioner 10 Compressor 12 Outdoor heat exchanger (condenser, evaporator)
13 Expansion valve 14 Indoor heat exchanger (evaporator, condenser)
30 Outdoor control unit (control means)

Claims (4)

A refrigerant circuit connecting a compressor, a condenser, an expansion valve and an evaporator;
Control means for controlling the compressor,
The control means includes
Stop control to stop the compressor when the refrigerant pressure reaches a predetermined pressure;
When a predetermined drooping condition is satisfied, drooping control is performed to reduce the frequency of the compressor,
In the drooping control,
When the stop control is executed and the compressor is stopped, the droop condition is corrected so that the droop condition becomes stricter than before the compressor stops, and
After the drooping condition is corrected, the correction of the drooping condition is returned when a predetermined release condition is satisfied. The air conditioner according to claim 1, wherein the predetermined release condition is that any one of conditions (1) to (3) is satisfied.
Condition (1): When a predetermined time has elapsed since the correction of the drooping condition was executed. Condition (2): When the operation of the air conditioner was stopped. Condition (3): When changed to another operation mode. The air conditioner according to claim 1, wherein the predetermined release condition satisfies the condition (1) and satisfies the condition (2) or (3).
Condition (1): When a predetermined time has elapsed since the correction of the drooping condition was executed. Condition (2): When the operation of the air conditioner was stopped. Condition (3): When changed to another operation mode.   The air conditioner according to any one of claims 1 to 3, wherein the predetermined drooping condition is determined based on a temperature of the condenser.

Images