KR102337730B1 - Air conditional and control method thereof - Google Patents

Abstract

An air conditioner according to an embodiment of the present invention includes: an outdoor unit including a plurality of outdoor heat exchangers, a compressor, and a plurality of four sides; at least one indoor unit connected to the outdoor unit and including an expansion valve and an indoor heat exchanger; a low pressure sensor for measuring the low pressure at the inlet of the compressor; a high pressure sensor for measuring the high pressure at the outlet of the compressor; and a control unit for controlling the plurality of sides and the compressor, wherein when the heating operation is turned off and the cooling operation starts, the control unit switches to the plurality of side cooling modes and starts the compressor, After starting, if the high and low pressure difference between the high and low pressure is less than or equal to the first reference value, and the ratio of high and low pressure between the high and low pressure is less than or equal to the second reference value, the compressor is turned off. to and restart the compressor, and after restarting the compressor, if the high and low pressure difference exceeds the first reference value or the high and low pressure ratio exceeds the second reference value, the plurality of four sides is re-switched to the cooling mode .

Description

Air conditioner and its control method {Air conditional and control method thereof}

The present invention relates to an air conditioner and a control method thereof.

In general, an air conditioner is a device that cools or purifies air by using a refrigerant cycle consisting of a compressor, a condenser, an expansion mechanism, and an evaporator in order to create a more comfortable indoor environment for users.

The air conditioner as described above includes an air conditioner in which one indoor unit is connected to one outdoor unit, and a multi-type air conditioner in which a plurality of indoor units are connected to one outdoor unit to obtain the same effect as installing several air conditioners.

Such a multi-type air conditioner is disclosed in the following prior literature.

1. Publication number (published date): 10-2008-0011258 (2008. 02. 01.)

2. Title of invention: Simultaneous heating and cooling multi-air conditioner

The prior literature discloses an air conditioner having a plurality of four sides, and when the operation mode of the air conditioner is changed from a cooling operation to a heating operation or from a heating operation to a cooling operation, the plurality of four sides is switched.

Meanwhile, in an air conditioner having a plurality of quadrilaterals, at least one of the plurality of quadrilaterals may not be successfully switched and thus the quadrilateral switching may fail. In this case, the air conditioner may not operate normally.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an air conditioner capable of determining switching failure of a plurality of four sides when an operation mode of the air conditioner is changed.

It is an object of the present invention to provide an air conditioner capable of normally switching when switching of the plurality of four sides fails.

An air conditioner according to an aspect of the present invention includes: an outdoor unit including a plurality of outdoor heat exchangers, a compressor, and a plurality of four sides; at least one indoor unit connected to the outdoor unit and including an expansion valve and an indoor heat exchanger; a low pressure sensor for measuring the low pressure at the inlet of the compressor; a high pressure sensor for measuring the high pressure at the outlet of the compressor; and a control unit for controlling the plurality of sides and the compressor, wherein when the heating operation is turned off and the cooling operation is started, the control unit switches to the plurality of side cooling modes and starts the compressor, After starting, if the high/low pressure difference between the high and low pressures is less than or equal to the first reference value, and the ratio of high and low pressures between the high and low pressures is less than or equal to the second reference value, the compressor is turned off. to and restart the compressor, and after restarting the compressor, if the high and low pressure difference exceeds the first reference value or the high and low pressure ratio exceeds the second reference value, the plurality of four sides is re-switched to the cooling mode .

In addition, the control unit, after switching the plurality of four sides to the cooling mode, characterized in that the first set time elapses to start the compressor.

In addition, the control unit, after turning off the compressor, when a second set time elapses, it characterized in that the plurality of four-sided switching to the heating mode.

In addition, the first set time is characterized in that longer than the second set time.

According to another aspect of the present invention, there is provided a method for controlling an air conditioner including a compressor, an outdoor unit including a plurality of four sides, and at least one indoor unit connected to the outdoor unit, the method comprising: heating operation is turned off and the cooling operation is on, switching the plurality of four sides to a cooling mode; starting the compressor after the plurality of four sides are switched to a cooling mode; after starting the compressor, turning off the compressor when the high-low pressure difference of the compressor is less than or equal to a first reference value and the high-low pressure ratio of the compressor is less than or equal to a second reference value; after the compressor is turned off, switching the plurality of four sides to a heating mode and restarting the compressor; and, after restarting the compressor, when the high/low pressure difference of the compressor exceeds the first reference value or the high/low pressure ratio exceeds the second reference value, re-switching the plurality of four sides to the cooling mode.

In addition, the step of performing a normal operation when the high-low pressure difference exceeds the first reference value or the high-low pressure ratio exceeds the second reference value after starting the compressor; further includes.

In addition, it is characterized in that the normal operation is performed after re-switching the plurality of four sides to the cooling mode.

In addition, after the step of switching the plurality of four sides to the cooling mode is finished, after a first set time has elapsed, the step of starting the compressor is performed.

In addition, when the step of turning off the compressor is finished, after a second set time has elapsed, the step of switching the plurality of four sides to a heating mode is performed.

In addition, the first set time is characterized in that it is set longer than the second time.

Further, the method further includes; after re-switching the plurality of four sides to the cooling mode, normal operation is performed when the high/low pressure difference exceeds the first reference value or the high/low pressure ratio exceeds the second reference value.

According to an embodiment of the present invention, when the operation mode is changed, there is an effect of determining whether or not the switching of the mortal disease is successful by the high-low pressure difference between the high and low pressures of the compressor and the high-low pressure ratio.

In addition, when it is determined that the four-way switching has failed, the compressor is turned off, the four-way state is returned to before the four-way switching, and the compressor is restarted to re-switch the four-way side while the differential pressure is formed. It has the effect of being able to switch normally by solving these problems by itself.

In addition, the compressor is turned off when the differential pressure of the compressor is not secured, and the compressor is turned on when the differential pressure of the compressor is secured, thereby preventing damage to the compressor by operating the compressor in a state where the differential pressure is not secured.

1 is a configuration diagram showing a heating operation of an air conditioner according to an embodiment of the present invention;
2 is a block diagram showing a cooling operation of the air conditioner according to an embodiment of the present invention;
3 is a block diagram schematically showing a control configuration of an air conditioner according to an embodiment of the present invention;
4 is a flowchart showing a process of changing an operation mode from a heating mode to a cooling mode according to the first embodiment of the present invention;
5 is a flowchart showing a process of changing an operation mode from a heating mode to a cooling mode according to a second embodiment of the present invention;

Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. However, the spirit of the present invention is not limited to the presented embodiments, and those skilled in the art who understand the spirit of the present invention will be able to easily suggest other embodiments within the scope of the same spirit.

1 is a configuration diagram showing a heating operation of an air conditioner according to an embodiment of the present invention. 2 is a block diagram showing a cooling operation of the air conditioner according to an embodiment of the present invention.

1 and 2 , the air conditioner 1 according to the embodiment of the present invention may include an outdoor unit 10 and at least one indoor unit 20 connected to the outdoor unit 10 .

The outdoor unit 10 includes a compressor 110 for compressing a refrigerant, a plurality of outdoor heat exchangers 150 through which outdoor air exchanges heat with the refrigerant, an outdoor expansion valve 160 for expanding the refrigerant, and the air conditioner 1 . It may include a plurality of four sides (141, 142) for changing the refrigerant flow path according to the cooling or heating operation mode of the. Meanwhile, the compressor 110 may be, for example, a differential pressure refueling type compressor.

The outdoor unit 10 is provided on the outlet side of the compressor 110 to separate the oil contained in the refrigerant discharged from the compressor 110 and supply it back to the compressor 110 , the oil separator 130 and the compressor An accumulator 120 provided on the inlet side of 110 to prevent liquid refrigerant from flowing into the compressor 110 may be further included.

The indoor unit 20 may include an indoor expansion valve 210 for expanding the refrigerant and an indoor heat exchanger 220 for heat-exchanging indoor air with the refrigerant.

The air conditioner 1 configured as described above may be operated in a heating operation mode. In this case, the plurality of four sides 141 and 142 may be switched to a heating mode, and the compressor 110 may be operated. can As shown in FIG. 1 , the refrigerant compressed in the compressor 110 may flow to the indoor unit 20 through the oil separator 130 . The oil separator 130 may separate oil contained in the refrigerant discharged from the compressor 110 and supply the oil back to the compressor 110 through a separately provided flow path.

The refrigerant flowing into the indoor unit 20 may be condensed in the indoor heat exchanger 220 in the indoor unit 20 . In the process of being condensed in the indoor heat exchanger 220 , heat is released from the refrigerant, so that the indoor space can be heated. In addition, the condensed refrigerant may flow toward the outdoor unit 10 without being expanded by the indoor expansion valve 210 .

The refrigerant flowing into the outdoor unit 10 may be expanded by the outdoor expansion valve 160 and introduced into the outdoor heat exchanger 150 . In the outdoor heat exchanger 150 , the expanded refrigerant may be evaporated. In addition, the evaporated refrigerant may pass through the plurality of four sides 141 and 142 and then re-introduce into the compressor 110 through the accumulator 120 .

Such a process may be continuously performed while the heating operation is performed, thereby heating the indoor space.

Meanwhile, in the case of the cooling operation, the plurality of four sides 141 and 142 may be switched to the cooling mode. Accordingly, the refrigerant compressed in the compressor 110 may flow into the outdoor heat exchanger 150 to condense the refrigerant as shown in FIG. 2 . In addition, the refrigerant condensed in the outdoor heat exchanger 150 may flow toward the indoor unit 20 , expand by the indoor expansion valve 210 , and evaporate in the indoor heat exchanger 220 . Further, the refrigerant condensed in the outdoor heat exchanger 150 may be expanded in the indoor expansion valve 210 without being expanded in the outdoor expansion valve 160 .

3 is a block diagram schematically showing a control configuration of an air conditioner according to an embodiment of the present invention.

Referring to FIG. 3 , the air conditioner 1 communicates with a wired or wireless remote controller (not shown) to receive a communication unit 40 for receiving an operation command of the air conditioner 1 and a timer 50 for time measurement. may include Then, the air conditioner 1 receives the command of the communication unit 40, receives the data of the high-pressure sensor 172 and the low-pressure sensor 171, the plurality of four sides (141, 142) and a control unit 30 for controlling the compressor 110 .

The controller 30 controls the first quadrilateral 141, the second quadrilateral 142 and The compressor 110 may be controlled. In addition, the controller 30 may receive the operation control command received from the communication unit 40 to control the first quadrilateral 141 , the second quadrilateral 142 , and the compressor. The command received from the communication unit 40 may be, for example, an “on/off command” for turning on/off the air conditioner 1 or a “mode change command” for changing the cooling/heating mode. However, the command received from the communication unit 40 is not limited thereto, and various commands may be received depending on the configuration of the air conditioner 1 .

Next, in FIGS. 4 and 5 , when a "mode change command" is received through the communication unit 40, a process of changing the operation mode from the heating mode to the cooling mode will be described in detail as an example.

4 is a flowchart illustrating a process of changing an operation mode from a heating mode to a cooling mode according to the first embodiment of the present invention.

Referring to FIG. 4 , when a “mode change command” for cooling operation is received through the communication unit 40 while the air conditioner 1 is performing a heating operation, the The heating operation may be turned off, and the cooling operation may be turned on (S101).

In addition, the controller 30 may switch the plurality of four sides 141 and 142 to the cooling mode according to the change of the operation mode (S102). At this time, the compressor 110 may be in an OFF state to change the operation mode.

When the plurality of quadrilaterals 141 and 142 are switched, the control unit 30 may wait for a first set time (S103). The first set time is a time for stabilizing the flow of the refrigerant after the plurality of four sides 141 and 142 are switched. For example, a predetermined time such as 1 minute, 3 minutes, or 5 minutes may be set.

The timer 50 may measure the time after the controller 30 switches the plurality of quadrilaterals 141 and 142 to the cooling mode, and the controller 30 controls the plurality of quadrilaterals 141 and 142 ) after switching to the cooling mode, the compressor 110 may maintain a stopped state until the measured time reaches the first set time.

After switching the plurality of four sides 141 and 142 to the cooling mode, the controller 30 may start the compressor 110 when the measured time elapses the first set time (S104).

The control unit 30 may operate the compressor 110 at a relatively low initial starting frequency and then increase the frequency up to a target frequency. Step S104 of starting the compressor 110 may include starting the compressor 110 up to a target frequency.

When the compressor 110 is operated, the control unit 30 controls the high and low pressure difference between the high pressure and the low pressure measured by the high pressure sensor 172 and the low pressure sensor 171 to exceed a first reference value, or It may be determined whether the low pressure ratio exceeds the second reference value (S105).

Step S105 of determining the high-low pressure ratio and the high-low pressure difference is a step for determining whether switching of the plurality of quadrilaterals 141 and 142 is normally performed.

When the high and low pressure difference exceeds the first reference value or the high and low pressure ratio exceeds the second reference value, the control unit 30 determines that switching of the plurality of four sides 141 and 142 is normally performed, and the air conditioner ( 1) may be operated normally in the cooling operation mode (S106).

The case in which the plurality of quadrilaterals 141 and 142 are normally switched is a case in which all of the plurality of quadrilaterals 141 and 142 are normally switched.

On the other hand, when the high-low pressure difference of the compressor 110 is less than or equal to the first reference value or the high-low pressure ratio of the compressor 110 is less than or equal to the second reference value, the control unit 30 switches the plurality of quadrilaterals 141 and 142 . It can be judged that this is not normally done.

The case where the switching of the plurality of quadrilaterals 141 and 142 is not normally performed is a case in which some of the plurality of quadrilaterals 141 and 142 are successfully switched and the other quadrilaterals are not switched.

When some of the four quadrilaterals 141 and 142 switch successfully and the other four quadrants fail to switch, a closed circuit is formed between the four quadrilaterals that have failed to be switched and the compressor 110, and in this state, the compressor 110 discharges the refrigerant. In this case, the high-pressure gas refrigerant compressed in the compressor 110 flows to all four sides, which is not switched, and to the flow path connected to the compressor 11 , and the high-low pressure difference or the high-low pressure ratio becomes low.

That is, when there is an unsuccessful switch among the plurality of quadrilaterals 141 and 142 , the high-low pressure difference may be less than or equal to the first reference value or the high-low pressure ratio may be less than or equal to the second reference value, and the control unit uses the high-low pressure difference and the high-low pressure ratio to It is possible to determine the success/failure of switching of the four sides (141, 142).

On the other hand, if the compressor is a differential pressure oil supply type compressor and the plurality of four sides 141 and 142 are not switched normally, and the compressor is driven, the oil in the oil separator 130 cannot be recovered to the compressor, and the compressor is may be damaged.

The air conditioner 1 is preferably controlled so that all of the plurality of quadrilaterals 141 and 142 are normally switched when switching of the plurality of quadrilaterals 141 and 142 is not normally performed.

To this end, when the high-low pressure difference of the compressor 110 is equal to or less than the first reference value and the high-low pressure ratio is less than or equal to the second reference value, the controller 30 may turn off the compressor 110 ( S107 ).

And, the control unit 30 may wait for a second set time. The second set time is a time for stabilizing the refrigerant, and for example, a predetermined time such as 20 seconds, 30 seconds, or 40 seconds may be set.

Meanwhile, the first set time may be longer than the second set time. When the second set time is excessively long, the user may mistake it for a malfunction, and it is preferable that the second set time is not set excessively long.

The timer 50 may measure the time when the controller 30 turns off the compressor 110 , and the controller 30 determines that the time measured after turning off the compressor 110 reaches the second set time. Until then, the compressor 110 may be kept stopped.

When the time measured after turning off the compressor 110 elapses a second set time, the control unit 30 may switch the plurality of quadrilaterals 141 and 142 to the heating mode (S109).

Switching the plurality of quadrilaterals 141 and 142 to the heating mode means returning the plurality of quadrilaterals 141 and 142 to a state before the operation mode change. Accordingly, among the plurality of quadrilaterals 141 and 142, the quadrilateral that has been successfully switched will be switched back to the previous state.

When all of the plurality of quadrilaterals 141 and 142 are switched to the heating operation state, the control unit 30 may restart the compressor 110 ( S110 ). The process of restarting the compressor 110 is the same as the step S104, and the frequency can be increased up to the target frequency by starting at a low initial frequency.

When the compressor 110 is restarted, the controller 30 controls the high and low pressure difference between the high pressure and the low pressure measured by the high pressure sensor 172 and the low pressure sensor 171 to exceed a first reference value, or It may be determined whether the low pressure ratio exceeds the second reference value (S111).

When the high and low pressure difference exceeds the first reference value or the high and low pressure ratio exceeds the second reference value, the control unit 30 may re-switch the plurality of four sides 141 and 142 to the cooling mode (S112) . And, the air conditioner 1 may be operated normally in the cooling operation mode (S106).

Meanwhile, when the high-low pressure difference is less than or equal to the first reference value and the high-low pressure ratio is less than or equal to the second reference value in step S111, the controller 30 may turn off the compressor 110 (S107). Then, after waiting for a second set time (S108), the plurality of four sides (141, 142) is switched to the heating mode (S109), the compressor 110 is restarted (S110), and the high and low pressure difference and high You will be able to judge the low pressure ratio again. However, since the plurality of quadrilaterals 141 and 142 are already switched to the heating state in the process of performing step S107 again, in the step of switching the plurality of quadrilaterals 141 and 142, the switched state is will keep

5 is a flowchart showing a process of changing an operation mode from a heating mode to a cooling mode according to a second embodiment of the present invention.

Steps S201 to S212 of FIG. 5 are mostly the same as those of the first embodiment. However, after re-switching the plurality of four sides 141 and 142 to the cooling mode (S212), the control unit 30 controls the high and low pressures measured by the high-pressure sensor 172 and the low-pressure sensor 171 . In the process of re-determining whether the high-low pressure difference exceeds the first reference value or whether the high-low pressure ratio of the high-pressure and low-pressure exceeds the second reference value (S204), it can be determined again whether switching of the four sides has been successful.

The above description is merely illustrative of the technical spirit of the present invention, and various modifications and variations will be possible without departing from the essential characteristics of the present invention by those skilled in the art to which the present invention pertains.

Therefore, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention, but to explain, and the scope of the technical spirit of the present invention is not limited by these embodiments.

The protection scope of the present invention should be construed by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

Claims (11)

an outdoor unit including a plurality of outdoor heat exchangers, a compressor, and a plurality of four sides;
at least one indoor unit connected to the outdoor unit and including an expansion valve and an indoor heat exchanger;
a low pressure sensor for measuring the low pressure at the inlet of the compressor;
a high pressure sensor for measuring the high pressure at the outlet of the compressor; and
A control unit for controlling the plurality of quadrilaterals and the compressor,
The control unit is
When the heating operation is turned off and the cooling operation is started, the compressor is started after switching to the plurality of four-way cooling modes,
After starting the compressor, if the high and low pressure difference exceeds the first reference value or the high and low pressure ratio exceeds the second reference value, normal operation is performed,
After the compressor is started, if the high/low pressure difference between the high pressure and the low pressure is less than or equal to a first reference value, and the high/low pressure ratio between the high and low pressure is less than or equal to a second reference value, the compressor is turned off;
After turning off the compressor, the plurality of four sides is switched to a heating mode and the compressor is restarted,
After restarting the compressor, if the high and low pressure difference exceeds the first reference value or the high and low pressure ratio exceeds the second reference value, the plurality of four sides is re-switched to the cooling mode,
The air conditioner according to claim 1, wherein after the plurality of four sides are re-switched to the cooling mode, the normal operation is performed when the high/low pressure difference exceeds the first reference value or the high/low pressure ratio exceeds the second reference value. The method of claim 1,
The control unit is
The air conditioner according to claim 1, wherein the compressor is started when a first set time elapses after switching the plurality of four sides to the cooling mode. 3. The method of claim 2,
The control unit is
The air conditioner according to claim 1, wherein after a second set time has elapsed after turning off the compressor, the plurality of four sides is switched to a heating mode. 4. The method of claim 3,
The first set time is longer than the second set time. A method for controlling an air conditioner including a compressor, an outdoor unit including a plurality of four sides, and at least one indoor unit connected to the outdoor unit, the method comprising:
switching the plurality of four sides to a cooling mode when the heating operation is turned off and the cooling operation is turned on;
starting the compressor after the plurality of four sides are switched to a cooling mode;
after starting the compressor, normal operation is performed when the high/low pressure difference exceeds the first reference value or the high/low pressure ratio exceeds the second reference value;
turning off the compressor when the high-low pressure difference of the compressor is less than or equal to a first reference value and the high-low pressure ratio of the compressor is less than or equal to a second reference value after starting the compressor;
after the compressor is turned off, switching the plurality of four sides to a heating mode and restarting the compressor;
after restarting the compressor, when the high/low pressure difference of the compressor exceeds a first reference value or the high/low pressure ratio exceeds a second reference value, re-switching the plurality of four sides to a cooling mode; and
A control method of an air conditioner comprising: after re-switching the plurality of four sides to the cooling mode, normal operation is performed when the high and low pressure difference exceeds the first reference value or the high and low pressure ratio exceeds the second reference value. delete delete 6. The method of claim 5,
When the step of switching the plurality of four sides to the cooling mode is finished, after a first set time has elapsed, the step of starting the compressor is performed. 6. The method of claim 5,
After the step of turning off the compressor is finished, after a second set time has elapsed, the step of switching the plurality of four sides to a heating mode is performed. 10. The method of claim 9,
The control method of the air conditioner, characterized in that the first set time is set longer than the second set time. delete

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