Air conditioner, air conditioner control method, and indoor unit

Abstract

An air conditioner control method according to an embodiment of the present disclosure comprises the steps of: performing a first operation corresponding to one of a cooling operation and a heating operation; stopping the first operation on the basis of a command to switch from the first operation to a second operation corresponding to the other of the cooling operation and the heating operation; in a state in which the first operation is stopped, performing pressure equilibrium control so that a refrigerant pressure difference between both sides of a switching valve for the second operation decreases; determining, on the basis of the pressure equilibrium control, whether the refrigerant pressure difference decreases; and determining whether to perform the second operation on the basis of the determination result.

Description

Air conditioner, control method of air conditioner, and indoor unit

[0001] One embodiment of the present disclosure relates to an air conditioner, a method for controlling an air conditioner, an indoor unit included in the air conditioner, and a computer-readable recording medium having a program for executing the air conditioner control method on a computer.

[0002] A multi-system air conditioner, known as a system air conditioner, includes one or more outdoor units and two or more indoor units and can perform centrally controlled air conditioning for an entire building or one or more floors of a building.

[0003] A multi-type air conditioner can control two or more indoor units to operate simultaneously in different operating modes (e.g., cooling operation and heating operation). The multi-type air conditioner can switch between the cooling operation and heating operation of each indoor unit.

[0004] When a transfer valve is suddenly opened to switch operating modes in a multi-type air conditioner, refrigerant flows from the high-pressure section to the low-pressure section, which can cause noise and vibration in the air conditioner or damage to the refrigerant pipes. Accordingly, control methods are being developed to reduce the refrigerant pressure difference that occurs during the switching of operating modes.

[0005] Furthermore, even if control is performed to reduce the refrigerant pressure difference, the pressure difference may not decrease normally if there is a malfunction in the valve equipped in the air conditioner or if a control error occurs. If the operating mode is changed while the refrigerant pressure difference has not been reduced, problems such as noise, vibration, and damage to the refrigerant pipes in the air conditioner will still persist.

[0006] A control method for an air conditioner according to one embodiment of the present disclosure, comprising an outdoor unit, a plurality of indoor units connected to the outdoor unit, and a mode change control device for connecting the outdoor unit and the plurality of indoor units and switching between cooling operation and heating operation of each indoor unit, comprises: a step of performing a first operation corresponding to either cooling operation or heating operation; a step of stopping the first operation based on a command to switch to a second operation corresponding to the other of the cooling operation or heating operation in the first operation; a step of performing pressure-balancing control such that, in a state where the first operation is stopped, the refrigerant pressure difference between both sides of a switching valve for the second operation is reduced; a step of determining whether the refrigerant pressure difference based on the pressure-balancing control is reduced; and a step of determining whether to perform the second operation based on the result of the determination.

[0007] An air conditioner according to one embodiment of the present disclosure comprises an outdoor unit, a plurality of indoor units connected to the outdoor unit, a mode change control device for connecting the outdoor unit and the plurality of indoor units and for switching between cooling operation and heating operation of each indoor unit, a memory comprising one or more storage media for storing one or more instructions, and at least one processor comprising a processing circuit.

[0008] By executing one or more instructions individually or in combination by the at least one processor according to one embodiment of the present disclosure, the air conditioner performs a first operation corresponding to either a cooling operation or a heating operation.

[0009] By executing the one or more instructions individually or in combination by the at least one processor according to one embodiment of the present disclosure, the air conditioner stops the first operation based on a switching instruction to a second operation corresponding to the other of the cooling operation or the heating operation in the first operation.

[0010] By executing one or more instructions individually or in combination by the at least one processor according to one embodiment of the present disclosure, the air conditioner performs pressure-balancing control such that the refrigerant pressure difference between both sides of the switching valve for the second operation is reduced when the first operation is stopped.

[0011] By executing the one or more instructions individually or in combination by the at least one processor according to one embodiment of the present disclosure, the air conditioner determines whether the refrigerant pressure difference based on the pressure equilibrium control is reduced.

[0012] By executing the one or more instructions individually or in combination by the at least one processor according to one embodiment of the present disclosure, the air conditioner determines whether to perform the second operation based on the result of the determination.

[0013] An indoor unit connected to an outdoor unit and a mode change control device according to one embodiment of the present disclosure comprises an indoor heat exchanger, an indoor EEV, an indoor unit communication unit, a memory comprising one or more storage media for storing one or more instructions, and at least one processor comprising a processing circuit.

[0014] According to one embodiment of the present disclosure, the one or more instructions are executed individually or in combination by the at least one processor, thereby the indoor unit performs a first operation corresponding to either a cooling operation or a heating operation by opening the indoor EEV, obtains a switching command to a second operation corresponding to the other of the cooling operation or the heating operation during the first operation, stops the first operation by controlling the indoor EEV to close based on the switching command, transmits a control signal corresponding to the switching command to the outdoor unit and the mode change control device through the indoor unit communication unit, determines whether the refrigerant pressure difference between both sides of the switching valve for the second operation is reduced while the first operation is stopped, and determines whether to perform the second operation by opening the indoor EEV based on the result of the determination.

[0015] A computer-readable recording medium is provided, on which a program for performing a control method of an air conditioner according to one embodiment of the present disclosure is recorded.

[0016] The present disclosure can be easily understood from the combination of the following detailed description and the accompanying drawings, where reference numerals denote structural elements.

[0017] FIG. 1 is a schematic diagram illustrating the configuration of an air conditioner according to one embodiment of the present disclosure.

[0018] FIG. 2a is a drawing for explaining components connected to a refrigerant pipe of an air conditioner according to one embodiment of the present disclosure.

[0019] FIG. 2b is a diagram schematically illustrating the flow of refrigerant according to the cooling operation and heating operation of an air conditioner according to one embodiment of the present disclosure.

[0020] FIG. 3 is a diagram illustrating a mode change control device for an air conditioner and the refrigerant flow of a plurality of indoor units according to one embodiment of the present disclosure.

[0021] FIG. 4a is a diagram illustrating the process of switching an air conditioner from cooling operation to heating operation according to one embodiment of the present disclosure.

[0022] FIG. 4b is a table to explain the valve operation when the air conditioner of FIG. 4a switches from cooling operation to heating operation.

[0023] FIG. 5a is a diagram illustrating the process of switching an air conditioner from heating operation to cooling operation according to one embodiment of the present disclosure.

[0024] FIG. 5b is a table to explain the valve operation when the air conditioner of FIG. 5a switches from heating operation to cooling operation.

[0025] FIG. 6a is a diagram illustrating the process of switching an air conditioner from cooling operation to heating operation according to one embodiment of the present disclosure.

[0026] FIG. 6b is a table to explain the valve operation when the air conditioner of FIG. 6a switches from cooling operation to heating operation.

[0027] FIG. 7a is a diagram illustrating the process of switching an air conditioner from cooling operation to heating operation according to one embodiment of the present disclosure.

[0028] FIG. 7b is a table to explain the valve operation when the air conditioner of FIG. 7a switches from cooling operation to heating operation.

[0029] FIG. 8a is a diagram illustrating a process in which an air conditioner according to one embodiment of the present disclosure switches from cooling operation to heating operation.

[0030] FIG. 8b is a table to explain the valve operation when the air conditioner of FIG. 8a switches from cooling operation to heating operation.

[0031] FIG. 9a is a diagram illustrating the process of switching an air conditioner from cooling operation to heating operation according to one embodiment of the present disclosure.

[0032] FIG. 9b is a table to explain the valve operation when the air conditioner of FIG. 9a switches from cooling operation to heating operation.

[0033] FIG. 10 is a block diagram of an indoor unit, a mode change control device, and an outdoor unit according to one embodiment of the present disclosure.

[0034] FIG. 11 is a flowchart illustrating a method for detecting a pressure-balancing control error when switching the operating mode of an air conditioner according to one embodiment of the present disclosure.

[0035] FIG. 12 is a flowchart illustrating a method for detecting a pressure-balancing control error when an air conditioner according to one embodiment of the present disclosure switches from cooling operation to heating operation.

[0036] FIG. 13 is a flowchart illustrating a method for detecting a pressure-balancing control error when an air conditioner according to one embodiment of the present disclosure switches from heating operation to cooling operation.

[0037] FIG. 14 is a diagram illustrating the operation of an air conditioner acquiring an operation mode switching command according to one embodiment of the present disclosure.

[0038] FIG. 15 is a flowchart illustrating a method for detecting a pressure-balancing control error when switching the operating mode of an air conditioner according to one embodiment of the present disclosure.

[0039] FIG. 16 is a detailed block diagram of an air conditioner according to one embodiment of the present disclosure.

[0040] The various embodiments of this document and the terms used therein are not intended to limit the technical features described in this document to specific embodiments, and should be understood to include various modifications, equivalents, or substitutions of said embodiments.

[0041] In relation to the description of the drawings, similar reference numerals may be used for similar or related components.

[0042] The singular form of the noun corresponding to the item may include one or multiple items, unless the relevant context clearly indicates otherwise.

[0043] In this document, each of the phrases such as "A or B", "at least one of A and B", "at least one of A or B", "A, B or C", "at least one of A, B and C", and "at least one of A, B, or C" may include any one of the items listed together in the corresponding phrase, or all possible combinations thereof.

[0044] The term “and / or” includes a combination of multiple related described components or any of the multiple related described components.

[0045] Terms such as "first," "second," or "first" or "second" may be used simply to distinguish a component from another component and do not limit the components in other aspects (e.g., importance or order).

[0046] Where any (e.g., 1st) component is referred to as "coupled" or "connected" to another (e.g., 2nd) component, with or without the terms "functionally" or "communicationly," it means that said any component may be connected to said other component directly (e.g., via a wire), wirelessly, or through a third component.

[0047] Terms such as “include” or “have” are intended to specify the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in this document, and do not preclude the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0048] When it is said that one component is “connected,” “combined,” “supported,” or “in contact” with another component, this includes not only cases where the components are directly connected, combined, supported, or in contact, but also cases where they are indirectly connected, combined, supported, or in contact through a third component.

[0049] When it is said that a component is located “on” another component, this includes not only cases where one component is in contact with the other, but also cases where another component exists between the two components.

[0050] In the present disclosure, "processor" may include various processing circuits and / or a plurality of processors. For example, the term "processor" as used herein, including in the claims, may include at least one processor and various processing circuits. In at least one processor, one or more processors may be configured to perform the various functions described herein in a distributed manner, either individually or collectively. As used herein, "processor," "at least one processor," and "one or more processors" may be configured to perform various functions. However, these terms cover, without limitation, situations where one processor performs some of the functions and other processor(s) perform other parts of the functions, and situations where a single processor can perform all functions. Additionally, at least one processor may include a combination of processors performing various functions of the disclosed functions in a distributed manner. At least one processor may execute program instructions to achieve or perform various functions.

[0051] In the present disclosure, the term “user” means a person who controls a system, function, or operation, and may include a developer, administrator, installer, or repair technician.

[0052] Hereinafter, air conditioners according to various embodiments will be described in detail with reference to the drawings.

[0053] FIG. 1 is a schematic diagram illustrating the configuration of an air conditioner according to one embodiment of the present disclosure. FIG. 2a is a diagram for explaining components connected to the refrigerant pipes of an air conditioner according to one embodiment of the present disclosure. With reference to FIG. 1 and FIG. 2a, components of an air conditioner (1000) according to one embodiment of the present disclosure will be described.

[0054] An air conditioner (1000) according to one embodiment of the present disclosure is a device that performs functions such as air purification, ventilation, humidity control, cooling, or heating in an air-conditioned space, and means a device having at least one of these functions. The air conditioner (1000) may be implemented in the form of a cooling unit, a heating unit, a heating and cooling unit, an air purifier, or a dehumidifier.

[0055] An air conditioner (1000) according to one embodiment of the present disclosure may include an outdoor unit (100), a plurality of indoor units (200-1, 200-2, ..., 200-n), and a mode change control device (300). The outdoor unit (100) may be provided in an outdoor space to perform heat exchange between outdoor air and refrigerant. The plurality of indoor units (200-1, 200-2, ..., 200-n) may be provided in an indoor space to perform heat exchange between indoor air and refrigerant. The mode change control device (300) may distribute refrigerant supplied from the outdoor unit (100) to the plurality of indoor units (200-1, 200-2, ..., 200-n) and allow cooling or heating to be performed selectively. An outdoor unit (100), a plurality of indoor units (200-1, 200-2, ..., 200-n), and a mode change control device (300) may be connected via a refrigerant pipe. In the present disclosure, each of the plurality of indoor units (200-1, 200-2, ... 200-n) may be referred to as an indoor unit (200).

[0056] Referring to FIG. 2a, the outdoor unit (100) may include a compressor (110) that compresses the refrigerant and an outdoor heat exchanger (120) that performs heat exchange between the outdoor air and the refrigerant.

[0057] Each of the plurality of indoor units (200-1, 200-2, ... 200-n) may include an indoor heat exchanger (210-1, 210-2, ..., 210-n: 210) that performs heat exchange between indoor air and refrigerant, and an indoor EEV (Electronic Expansion Valve) (220-1, 220-2, ..., 220-n: 220) that reduces the pressure of the refrigerant supplied to the indoor heat exchanger (210) during cooling.

[0058] Here, the EEV may be a valve that controls the amount of refrigerant passing through the EEV or the pressure of the refrigerant by controlling the opening degree (i.e., the degree of valve opening). When the opening degree is expressed as an opening rate from 0% to 100%, an opening degree of 0% may mean a state where the valve is completely closed, and an opening degree of 100% may mean a state where the valve is completely open. The minimum opening degree refers to a state where the EEV is opened to the minimum extent and has a predetermined opening degree greater than 0%. When the EEV is opened to the minimum opening degree, the EEV may be used as an expansion device to increase the refrigerant pressure difference on both sides of the valve. The maximum opening degree refers to a state where the EEV is opened to the maximum extent and may correspond to an opening degree of 100%, but is not limited thereto. When the EEV is opened to the maximum opening degree, the refrigerant can pass freely through the EEV, so the refrigerant pressure difference on both sides of the valve may be reduced. The EEV may be referred to as an electronic expansion valve, an electric valve, an electronic valve, etc.

[0059] A mode change control device (300) is provided between an outdoor unit (100) and an indoor unit (200) and can deliver refrigerant provided from the outdoor unit (100) to each of the refrigerant pipes of the plurality of indoor units (200-1, 200-2, ..., 200-n). For example, the mode change control device (300) can selectively deliver liquid refrigerant or high-pressure gaseous refrigerant delivered from the outdoor unit (100) to each of the plurality of indoor units (200-1, 200-2, ..., 200-n). The mode change control device (300) can control each of the plurality of indoor units (200-1, 200-2, ..., 200-n) to operate in different modes simultaneously.

[0060] The mode change control device (300) can switch between the cooling operation and the heating operation of the indoor unit (200). The mode change control device (300) may be referred to as a distributor or as a mode change unit (MCU) that controls the switching between the cooling operation and the heating operation.

[0061] The mode change control device (300) is provided inside the refrigerant pipe and may include a transfer valve that controls the flow of refrigerant according to the operating mode of the air conditioner (1000), namely heating operation and cooling operation. For example, the transfer valve may include a heating valve and a cooling valve. Each of the heating valve and the cooling valve may be provided in multiple numbers according to the number of indoor units provided in the air conditioner (1000). For example, the mode change control device (300) may include a plurality of heating valves (310-1, 310-2, ..., 310-n: 310) and a plurality of cooling valves (320-1, 320-2, ..., 320-n: 320). The mode change control device (300) can change the direction of refrigerant flow by opening one of the heating valve and the cooling valve provided corresponding to each indoor unit and closing the other, depending on the operating mode of each indoor unit.

[0062] The outdoor unit (100) and the mode change control device (300) can be connected through a high-pressure gas pipe, a low-pressure gas pipe, and a liquid pipe. The mode change control device (300) and a plurality of indoor units (200-1, 200-2, ..., 200-n) can be connected through a refrigerant pipe and a liquid pipe corresponding to the high-pressure gas pipe or the low-pressure gas pipe.

[0063] FIG. 2b is a diagram schematically illustrating the flow of refrigerant according to the cooling and heating operations of an air conditioner according to one embodiment of the present disclosure. For convenience of explanation, content that overlaps with that described in FIG. 1 and FIG. 2a is omitted. In FIG. 2b, it is assumed that the heating valve (310) corresponds to any one of a plurality of heating valves (310-1, 310-2, ..., 310-n), the cooling valve (320) corresponds to any one of a plurality of cooling valves (320-1, 320-2, ..., 320-n), the indoor unit (200) corresponds to any one of a plurality of indoor units (200-1, 200-2, ..., 200-n), the indoor heat exchanger (210) corresponds to any one of an indoor heat exchanger (210-1, 210-2, ..., 210-n), and the indoor EEV (220) corresponds to any one of an indoor EEV (220-1, 220-2, ..., 220-n).

[0064] Referring to the cooling operation (201) of FIG. 2b, during the cooling operation (201) of the indoor unit (200), the cooling valve (320) may be in an open state and the heating valve (310) may be in a closed state. The high-pressure liquid refrigerant delivered through the liquid pipe (316) passes through the indoor EEV (220) to become a low-pressure liquid refrigerant, then performs heat exchange in the indoor heat exchanger (210), and then becomes a low-pressure gaseous state. The low-pressure gaseous refrigerant may pass through the cooling valve (320) and exit through the low-pressure gas pipe (314). The low-pressure gaseous refrigerant may be delivered to the outdoor unit (100).

[0065] The indoor heat exchanger (210) can perform heat exchange between the refrigerant and the air by utilizing the phase change (e.g., evaporation) of the refrigerant. For example, while the low-pressure liquid refrigerant flowing through the indoor heat exchanger (210) evaporates, the refrigerant can absorb heat from the air. The indoor space can be cooled by blowing air that has been cooled while passing through the cooled indoor heat exchanger (210). The indoor heat exchanger (210) receives low-temperature, low-pressure liquid refrigerant from the outdoor unit (100) and can discharge low-pressure gaseous refrigerant to the mode change control device (300) through heat exchange.

[0066] Referring to the heating operation (202) of FIG. 2b, when the indoor unit (200) is in heating operation (202), the heating valve (310) may be in an open state and the cooling valve (320) may be in a closed state. After the refrigerant in a high-pressure gas state delivered through the high-pressure gas pipe (311) passes through the heating valve (310), it performs heat exchange in the indoor heat exchanger (210), then exits as high-pressure liquid refrigerant and can pass through the indoor EEV (220). The low-pressure liquid refrigerant that has passed through the indoor EEV (220) can be delivered to the outdoor unit (100) through the liquid pipe (316).

[0067] The indoor heat exchanger (210) can perform heat exchange between the refrigerant and the air by utilizing the phase change (e.g., condensation) of the refrigerant. For example, while the refrigerant in a high-pressure gaseous state is condensed in the indoor heat exchanger (210), the refrigerant can release heat to the air. The space can be heated by blowing air heated while passing through the high-temperature indoor heat exchanger (210). The indoor heat exchanger (210) receives high-temperature, high-pressure gaseous refrigerant from the outdoor unit (100) and the mode change control device (300), and can discharge high-pressure liquid refrigerant to the indoor EEV (220) through heat exchange.

[0068] The air conditioner (1000) can switch between the cooling operation (201) and the heating operation (202) of the indoor unit (200) through the mode change control device (300). For example, the air conditioner (1000) can stop the operation of the indoor unit (200) and open the other of the heating valve (310) and the cooling valve (320) to switch the operation mode while either the heating valve (310) or the cooling valve (320) is open.

[0069] In this case, when switching the operating mode, the refrigerant pressure difference between both sides of the switching valve (e.g., heating valve (310) and cooling valve (320)) may be large. If the switching valve is suddenly opened, the refrigerant in the high-pressure section flows into the low-pressure section, causing significant noise and vibration in the indoor unit (200) and the mode change control device (300). In severe cases, this may also cause damage to the piping structure. An air conditioner (1000) according to one embodiment of the present disclosure may perform pressure equalization control to equalize the pressure on both sides of the switching valve when switching the operating mode. The air conditioner (1000) may use a pressure equalization EEV for pressure equalization control. The pressure equalization EEV can adjust the refrigerant pressure by controlling the opening degree so that the pressure difference between the high-pressure section and the low-pressure section is reduced. Accordingly, even if the switching valve is opened for the next refrigerant cycle, refrigerant flow noise and vibration may be significantly reduced.

[0070] For example, when the cooling valve (320) is open and the heating valve (310) is closed for cooling operation (201) of the indoor unit (200), both sides of the closed heating valve (310) can form a high-pressure section and a low-pressure section, respectively. In other words, the high-pressure gas pipe (311) connected to the first side of the heating valve (310) (e.g., the outdoor unit (100) side) becomes the high-pressure section, and the refrigerant pipe (312) connected to the second side of the heating valve (310) (e.g., the indoor unit (200) side) becomes the low-pressure section. In this state, when the heating valve (310) is suddenly opened for heating operation (202), noise is generated as the refrigerant in the high-pressure section flows into the low-pressure section. However, as in one embodiment of the present disclosure, when the pressure-balanced EEV is controlled while the operation is stopped, the refrigerant pressure in the low-pressure section increases, and consequently, the pressure difference between the high-pressure section and the low-pressure section can be reduced. In this way, when the pressure difference between the high-pressure section and the low-pressure section is reduced, even if the heating valve (310) is opened for heating operation (202), a sudden flow of refrigerant does not occur, so the refrigerant flow noise can be reduced. In the present disclosure, the first side of the heating valve (310) is exemplified as being the outdoor unit (100) side, and the second side of the heating valve (310) is exemplified as being the indoor unit (200) side.

[0071] Additionally, for example, when the heating valve (310) is open and the cooling valve (320) is closed for heating operation (202) of the indoor unit (200), both sides of the closed cooling valve (320) can form a high-pressure section and a low-pressure section, respectively. In other words, the low-pressure gas pipe (314) connected to the first side of the cooling valve (320) (e.g., the outdoor unit (100) side) becomes the low-pressure section, and the refrigerant pipe (312) connected to the second side of the cooling valve (320) (e.g., the indoor unit (200) side) becomes the high-pressure section. In this state, when the cooling valve (320) is suddenly opened for cooling operation (201), noise is generated as the refrigerant in the high-pressure section flows into the low-pressure section. However, as in one embodiment of the present disclosure, when the pressure-balanced EEV is controlled while the operation is stopped, the refrigerant pressure in the high-pressure section is reduced, and consequently, the pressure difference between the high-pressure section and the low-pressure section can be reduced. In this way, when the pressure difference between the high-pressure section and the low-pressure section is reduced, even if the cooling valve (320) is opened for cooling operation (201), a sudden flow of refrigerant does not occur, so the refrigerant flow noise can be reduced. In the present disclosure, the first side of the cooling valve (320) is exemplified as being the outdoor unit (100) side, and the second side of the cooling valve (320) is exemplified as being the indoor unit (200) side.

[0072] For example, the air conditioner (1000) can perform control to increase the pressure of the refrigerant before the high-pressure gaseous refrigerant used for heating operation is introduced after performing cooling operation. In other words, the air conditioner (1000) can increase the pressure of the refrigerant in the low-pressure section before switching from cooling operation to heating operation. For example, the air conditioner (1000) can perform control to decrease the pressure of the refrigerant before the low-pressure gaseous refrigerant used for cooling operation is introduced after performing heating operation. In other words, the air conditioner (1000) can decrease the pressure of the refrigerant in the high-pressure section before switching from heating operation to cooling operation.

[0073] Hereinafter, with reference to FIGS. 4a to 9a, an operation of reducing the pressure difference between a high-pressure section and a low-pressure section using various types of pressure-balanced EEVs according to one embodiment of the present disclosure is described. For example, the pressure-balanced EEV may include at least one of the indoor EEV (220) of FIG. 4a, the cooling sub-valve (430) of FIG. 5a, the heating EEV (610) of FIG. 6a, the cooling EEV (620) of FIG. 7a, the heating sub-valve (830) of FIG. 8a, or the cooling sub-valve (840) of FIG. 9a. This will be described in each figure.

[0074] Additionally, with reference to FIGS. 11 to 15, an operation to detect whether pressure balancing has been successfully performed is described before the air conditioner (1000) according to one embodiment of the present disclosure switches the operating mode. If there is a malfunction, such as foreign matter jamming in the EEV type valve, while the air conditioner (1000) is performing pressure balancing control, pressure balancing may not be performed normally. If the switching valve is opened while the pressure difference between both sides of the switching valve has not decreased, significant noise and vibration may still occur in the indoor unit (200) and the mode change control device (300). For example, if the air conditioner (1000) determines that the temperature of the indoor heat exchanger has not reached a certain level even after pressure balancing control is completed, it may control the operation to stop and display an error code. The air conditioner (1000) may switch the operating mode only when the temperature of the indoor heat exchanger reaches a certain level after pressure balancing control is completed. Accordingly, the air conditioner (1000) can prevent or reduce refrigerant flow noise and vibration that occur when switching operating modes.

[0075] Hereinafter, with reference to FIGS. 3 to 5b, an air conditioner (1000) including a mode change control device (300a) according to one embodiment of the present disclosure will be described.

[0076] FIG. 3 is a diagram illustrating a mode change control device for an air conditioner and the refrigerant flow of a plurality of indoor units according to one embodiment of the present disclosure.

[0077] Referring to FIG. 3, for convenience of explanation, details that overlap with those described in FIG. 1 to 2b are omitted. An air conditioner (1000) according to one embodiment of the present disclosure may include an outdoor unit (100), a plurality of indoor units (200-1, 200-2, ..., 200-n), and a mode change control device (300a). The mode change control device (300a) may include a heating main valve (410-1, 410-2, ..., 410-n: 410 in FIG. 4a), a cooling main valve (420-1, 420-2, ..., 420-n: 420 in FIG. 4a), and a cooling sub valve (430-1, 430-2, ..., 430-n: 430 in FIG. 4a). Each of the plurality of indoor units (200-1, 200-2, ..., 200-n) can be connected to a refrigerant pipe (312-1, 312-2, ..., 312-n) and a liquid pipe (316-1, 316-2, ..., 316-n). The mode change control device (300a) of FIG. 3 may correspond to the mode change control device (300) of FIG. 1 to 2b. The heating main valve (410) of FIG. 3 may correspond to the heating valve (310) of FIG. 2a. The cooling main valve (420) of FIG. 3 may correspond to the cooling valve (320) of FIG. 2a. Compared to the mode change control device (3000) of FIG. 1 to 2b, the mode change control device (300a) of FIG. 3 may further include a cooling sub-valve (430).

[0078] According to one embodiment of the present disclosure, the heating main valve (410) and the cooling main valve (420) may be solenoid-type valves. A solenoid-type valve controls the opening and closing of the valve using an electromagnetic coil (i.e., a solenoid) and can completely open or completely close the flow of a specific section through ON control or OFF control. However, not limited thereto, the heating main valve (410) and the cooling main valve (420) may be EEV valves for controlling the rated flow. An EEV valve for the rated flow may be a valve for controlling the flow of refrigerant to flow at a constant, fixed amount through opening adjustment.

[0079] The cooling sub-valve (430) may be an EEV type valve. The cooling sub-valve (430) may be used as a pressure-balanced EEV of the air conditioner (1000) when switching from heating operation to cooling operation. The mode change control device (300a) can control the opening of the cooling sub-valve (430) to be opened in a state prior to the start of cooling operation after the heating operation of the indoor unit (200) has stopped. When the cooling sub-valve (430) is opened while the operation of the indoor unit (200) has stopped, the pressure of the refrigerant in the high-pressure section may be reduced. In other words, the cooling sub-valve (430) can lower the pressure difference between the high-pressure section and the low-pressure section by lowering the pressure of the refrigerant in the high-pressure section. This is explained in the pressure-balanced step (503) of FIG. 5a.

[0080] Meanwhile, when switching from cooling operation to heating operation, the indoor EEV (220) can be used as a pressure-balanced EEV, and this is explained in the pressure-balanced step (403) of FIG. 4a.

[0081] The indoor unit (200) may include an indoor fan (230) that circulates indoor air to exchange heat with an indoor heat exchanger (210), and a refrigerant temperature sensor. The refrigerant temperature sensor may include an inlet temperature sensor (242) that senses the inlet refrigerant temperature of the indoor heat exchanger (210) and an outlet temperature sensor (241) that senses the outlet refrigerant temperature of the indoor heat exchanger (210), but is not limited thereto.

[0082] The mode change control device (300a) may further include a subcooler (440-1, 440-2, ..., 440-n) and a subcooling EEV (450). The subcooler (440-1, 440-2, ..., 440-n) can secure the degree of subcooling of the indoor unit (200) performing cooling operation. For example, the subcooler (440-1, 440-2, ..., 440-n) can perform the role of supplying liquid refrigerant discharged after one indoor unit (e.g., 200-n) performs heating operation to the cooling cycle of another indoor unit (e.g., 200-1). Accordingly, a sufficient amount of liquid refrigerant used for cooling the indoor unit can be secured. For example, the nth indoor unit (200-n) can discharge liquid refrigerant through the liquid pipe (316-n) after heating operation. As the discharged liquid refrigerant passes through the nth subcooler (440-n), it may not be returned to the outdoor unit (100) but may flow back into the first indoor unit (200-1). The subcooling EEV (450) can secure the superheating degree of the subcoolers (440-1, 440-2, ..., 440-n) and prevent or reduce the inflow of liquid refrigerant.

[0083] FIG. 4a is a diagram illustrating the process of switching an air conditioner according to an embodiment of the present disclosure from cooling operation to heating operation. FIG. 4b is a table illustrating the valve operation when the air conditioner of FIG. 4a switches from cooling operation to heating operation. In FIG. 4a and FIG. 4b, the air conditioner (1000) according to an embodiment of the present disclosure may include a mode change control device (300a). For convenience of explanation, content that overlaps with the content described in FIG. 1 to FIG. 3 is omitted.

[0084] In the cooling operation stage (401), the air conditioner (1000) can perform cooling operation by controlling the cooling main valve (420) and the indoor EEV (220) to open. The high-pressure liquid refrigerant delivered through the liquid pipe (316) passes through the indoor EEV (220) to become low-pressure liquid refrigerant, then performs heat exchange in the indoor heat exchanger (210), and then becomes low-pressure gaseous. The low-pressure gaseous refrigerant can pass through the cooling main valve (420) and exit through the low-pressure gas pipe (314). The low-pressure gaseous refrigerant can be delivered to the outdoor unit (100). This corresponds to the cooling operation (201) of FIG. 2B. Additionally, in the cooling operation stage (401), since the cooling sub-valve (430) is open, the refrigerant in a low-pressure gaseous state can also escape through the cooling sub-valve (430) into the low-pressure gas pipe (314). Here, the heating main valve (410) may be in a closed state.

[0085] An air conditioner (1000) according to one embodiment of the present disclosure may operate in the order of a cooling stop step (402), a pressure equalization step (403), and a heating operation step (404) based on a command to switch from cooling operation to heating operation. Before opening the heating main valve (410), the air conditioner (1000) may equalize the pressure between both sides of the heating main valve (410).

[0086] In the cooling stop step (402), the air conditioner (1000) can stop cooling operation by controlling the cooling main valve (420), cooling sub valve (430), and indoor EEV (220) to close. When the operation of the indoor unit (200) is stopped, the refrigerant flow of the indoor unit (200) can be blocked. In this case, the refrigerant pipe (312) can form a low-pressure section. The refrigerant in the refrigerant pipe (312) may be in a two-phase state in which low-pressure liquid and low-pressure gas coexist.

[0087] In the pressure-balancing stage (403) through the high-pressure operation of the indoor unit (200), the air conditioner (1000) can control the indoor EEV (220) to open, thereby increasing the pressure of the refrigerant flowing through the indoor unit (200). When the air conditioner (1000) is in a stopped state, the indoor EEV (220) can be used as a pressure-balancing EEV by opening the indoor EEV (220) to a predetermined opening. When the indoor EEV (220) is opened, the liquid refrigerant in a somewhat high-pressure state introduced through the liquid pipe (316) can pass through the indoor EEV (220) and flow into the indoor heat exchanger (210) and the refrigerant pipe (312). Accordingly, the pressure of the low-pressure section formed in the indoor heat exchanger (210) and the refrigerant pipe (312) can be increased. Ultimately, when the heating main valve (410) is opened to switch the operating mode, the refrigerant pressure difference between the high-pressure gas pipe (311) connected to the first side of the heating main valve (410) and the refrigerant pipe (312) connected to the second side of the heating main valve (410) can be reduced. Meanwhile, when the indoor EEV (220) used as a pressure-balanced EEV is opened to a predetermined opening, the flow rate of the refrigerant flowing through the indoor EEV (220) can be high. Here, the predetermined opening may represent an opening greater than the opening during normal cooling operation. The predetermined opening may be set to an appropriate opening such that, at least, the indoor EEV (220) is small enough so that no noise is generated when it is suddenly opened, and the time required for pressure-balanced control is not too long.

[0088] In the heating operation stage (404), the air conditioner (1000) can start the heating operation of the indoor unit (200) by controlling the heating main valve (410) to open when the refrigerant pressure in the indoor heat exchanger (210) and the refrigerant pipe (312) is increased. The air conditioner (1000) can open the indoor EEV (220) to a higher opening than a predetermined opening, so that the indoor EEV (220) can be used as an expansion device. For example, in the heating operation, the indoor EEV (220) acts as a flow rate control, so the opening can be controlled in a larger range than in the cooling operation (e.g., near the maximum opening).

[0089] An air conditioner (1000) according to one embodiment of the present disclosure can prevent or reduce problems such as noise, shock, and refrigerant pipe damage that occur when the cooling main valve (420) is immediately closed and the heating main valve (410) is opened when switching from cooling operation to heating operation.

[0090] Additionally, in the pressure balancing step (403) according to one embodiment of the present disclosure, the air conditioner (1000) may control the cooling sub-valve (430) to close. However, if there is a valve failure due to foreign matter jamming inside the EEV type cooling sub-valve (430), even if the air conditioner (1000) controls the cooling sub-valve (430) to close, it may not close completely. When the cooling sub-valve (430) is slightly open, the refrigerant in the refrigerant pipe (312) connected to the second side of the heating main valve (410) may escape to the cooling sub-valve (430) side, and the refrigerant pressure in the refrigerant pipe (312) may not increase or may increase less. Accordingly, the refrigerant pressure difference between the high-pressure section and the low-pressure section on both sides of the heating main valve (410) may not decrease. Ultimately, if the heating main valve (410) is opened while the refrigerant pressure difference is not reduced, significant noise and vibration may occur in the indoor unit (200) and the mode change control device (300a). An air conditioner (1000) according to one embodiment of the present disclosure may determine whether to perform a heating operation step (404) after performing a pressure equilibration step (403) and determining whether the pressure equilibration was successfully performed. This is explained in FIGS. 11 and 12.

[0091] FIG. 5a is a diagram illustrating the process of switching an air conditioner according to an embodiment of the present disclosure from a heating operation to a cooling operation. FIG. 5b is a table illustrating the valve operation when the air conditioner of FIG. 5a switches from a heating operation to a cooling operation. In FIG. 5a and FIG. 5b, the air conditioner (1000) according to an embodiment of the present disclosure may include a mode change control device (300a). For convenience of explanation, content that overlaps with the content described in FIG. 1 to FIG. 3 is omitted.

[0092] In the heating operation stage (501), the air conditioner (1000) can perform heating operation by controlling the heating main valve (410) and the indoor EEV (220) to open. After the refrigerant in a high-pressure gaseous state delivered through the high-pressure gas pipe (311) passes through the heating main valve (410), performs heat exchange in the indoor heat exchanger (210), and then exits as high-pressure liquid refrigerant and passes through the indoor EEV (220). The low-pressure liquid refrigerant that passes through the indoor EEV (220) can be delivered to the outdoor unit (100) through the liquid pipe (316). This corresponds to the heating operation (202) of FIG. 2b. Here, the cooling main valve (420) and the cooling sub valve (430) may be in a closed state.

[0093] An air conditioner (1000) according to one embodiment of the present disclosure may operate in the order of a heating stop step (502), a pressure equalization step (503), and a cooling operation step (504) based on a command to switch from a heating operation to a cooling operation. Before opening the cooling main valve (420), the air conditioner (1000) may equalize the pressure between both sides of the cooling main valve (420).

[0094] In the heating stop step (502), the air conditioner (1000) can stop the heating operation by controlling the heating main valve (410) and the indoor EEV (220) to close. When the operation of the indoor unit (200) is stopped, the refrigerant flow of the indoor unit (200) can be blocked. In this case, the refrigerant pipe (312) can form a high-pressure section. The refrigerant in the refrigerant pipe (312) may be in a two-phase state in which high-pressure liquid and high-pressure gas coexist.

[0095] In the pressure-balancing stage (503) through the low-pressure reduction of the indoor unit (200), the air conditioner (1000) can control the cooling sub-valve (430) to open, thereby lowering the pressure of the refrigerant flowing through the indoor unit (200). When the air conditioner (1000) is stopped from operating, the open cooling sub-valve (430) can be used as a pressure-balancing EEV. When the cooling sub-valve (430) is opened, the refrigerant in the high-pressure state of the refrigerant pipe (312) can pass through the cooling sub-valve (430) and flow into the low-pressure gas pipe (314). Accordingly, the pressure of the high-pressure section formed in the indoor heat exchanger (210) and the refrigerant pipe (312) can be reduced. Ultimately, when the cooling main valve (420) is opened to switch the operating mode, the refrigerant pressure difference between the low-pressure gas pipe (314) connected to the first side of the cooling main valve (420) and the refrigerant pipe (312) connected to the second side of the cooling main valve (420) can be reduced.

[0096] In the cooling operation stage (504), the air conditioner (1000) can start the cooling operation of the indoor unit (200) by opening the cooling main valve (420) and controlling the indoor EEV (220) to open when the refrigerant pressure in the indoor heat exchanger (210) and the refrigerant pipe (312) is reduced. Here, the heating main valve (410) may be in a closed state. Also, although the cooling sub valve (430) is exemplified as being in a closed state, it may be in an open state. For example, in the cooling operation, the indoor EEV (220) acts as an expansion valve, so the opening can be controlled in a smaller range than in the heating operation.

[0097] An air conditioner (1000) according to one embodiment of the present disclosure can prevent or reduce problems such as noise, shock, and refrigerant pipe damage that occur when the heating main valve (410) is immediately closed and the cooling main valve (420) is opened when switching from heating operation to cooling operation.

[0098] An air conditioner (1000) according to one embodiment of the present disclosure may, after performing a pressure equilibration step (503), determine whether the pressure equilibration was successfully performed and then determine whether to perform a cooling operation step (504). This is explained in FIGS. 11 and 13.

[0099] Meanwhile, the heating sub-valve may be omitted from the components of the mode change control device (300a) of FIGS. 4a to 5b compared to the mode change control device (300c) of FIGS. 8a to 9b. The air conditioner (1000) including the mode change control device (300a) can lower the pressure of the refrigerant flowing in the indoor unit (200) using an indoor EEV (220) instead of a heating sub-valve (i.e., pressure equilibration step (403)). Accordingly, the cost of manufacturing the air conditioner (1000) including the mode change control device (300a) can be reduced.

[0100] Hereinafter, with reference to FIGS. 6a to 7b, an air conditioner (1000) including a mode change control device (300b) according to one embodiment of the present disclosure will be described.

[0101] FIG. 6a is a diagram illustrating a process in which an air conditioner according to one embodiment of the present disclosure switches from cooling operation to heating operation. FIG. 6b is a table illustrating valve operation when the air conditioner of FIG. 6a switches from cooling operation to heating operation.

[0102] An air conditioner (1000) according to one embodiment of the present disclosure may include an outdoor unit (100), an indoor unit (200), and a mode change control device (300b). The mode change control device (300b) may include a heating EEV (610) and a cooling EEV (620). The mode change control device (300b) of FIGS. 6a and 7a may correspond to the mode change control device (300) of FIGS. 1 to 2b. The heating EEV (610) of FIGS. 6a and 7a may correspond to the heating valve (310) of FIG. 2a. The cooling EEV (620) of FIGS. 6a and 7a may correspond to the cooling valve (320) of FIG. 2a. The mode change control device (300b) differs in that it includes a heating EEV (610) and a cooling EEV (620) instead of the heating main valve (410), cooling main valve (420), and cooling sub-valve (430) of the mode change control device (300a) of FIG. 4a and FIG. 5a.

[0103] A heating EEV (610) and a cooling EEV (620) according to one embodiment of the present disclosure may be EEV valves for controlling a fine flow rate. An EEV valve for a fine flow rate may be a valve for finely controlling the flow rate of a refrigerant through fine adjustment of the opening degree. Accordingly, the heating EEV (610) and the cooling EEV (620) may control not only the flow rate of the refrigerant but also the pressure of the refrigerant by adjusting the opening degree.

[0104] Each of the heating EEV (610) and cooling EEV (620) according to one embodiment of the present disclosure may be used as a valve for heating operation and cooling operation, or as a pressure-balanced EEV, depending on the size of the opening. For example, the air conditioner (1000) may use the heating EEV (610) and cooling EEV (620) as a pressure-balanced EEV of the air conditioner (1000) by slightly increasing the opening (e.g., minimum opening). Alternatively, the air conditioner (1000) may use the heating EEV (610) and cooling EEV (620) as a valve for heating operation and cooling operation by increasing the opening to a higher opening.

[0105] For example, the heating EEV (610) can be used as a pressure-balancing EEV when switching from cooling operation to heating operation. This is explained in the pressure-balancing step (603) of FIG. 6a. For example, the cooling EEV (620) can be used as a pressure-balancing EEV when switching from heating operation to cooling operation. This is explained in the pressure-balancing step (703) of FIG. 7a.

[0106] In the cooling operation stage (601), the air conditioner (1000) can perform cooling operation by controlling the cooling EEV (620) and the indoor EEV (220) to open. High-pressure liquid refrigerant is delivered to the indoor EEV (220) through the liquid pipe (316), and low-pressure gaseous refrigerant can exit through the low-pressure gas pipe (314). This corresponds to the cooling operation (201) of FIG. 2B. Here, the cooling EEV (620) may be open to an opening higher than the minimum opening. Here, the heating EEV (610) may be closed.

[0107] An air conditioner (1000) according to one embodiment of the present disclosure may operate in the order of a cooling stop step (602), a pressure equalization step (603), and a heating operation step (604) based on a command to switch from cooling operation to heating operation. Before opening the heating EEV (610), the air conditioner (1000) may equalize the pressure between both sides of the heating EEV (610).

[0108] In the cooling stop phase (602), the air conditioner (1000) can stop cooling operation by controlling the cooling EEV (620) and the indoor EEV (220) to close. When the operation of the indoor unit (200) is stopped, the refrigerant flow of the indoor unit (200) can be blocked. In this case, the refrigerant pipe (312) can form a low-pressure section.

[0109] In the pressure-balancing stage (603) through the high-pressure operation of the indoor unit (200), the air conditioner (1000) can control the heating EEV (610) to open, thereby increasing the pressure of the refrigerant flowing through the indoor unit (200). When the air conditioner (1000) is in a stopped state, the heating EEV (610) can be used as a pressure-balancing EEV by opening the heating EEV (610) to a minimum opening. When the heating EEV (610) is opened to a minimum opening, the gaseous refrigerant in a high-pressure state can flow through the high-pressure gas pipe (311) to the refrigerant pipe (312) and the indoor heat exchanger (210). Accordingly, the pressure of the low-pressure section formed in the refrigerant pipe (312) and the indoor heat exchanger (210) can be increased. Ultimately, when the heating EEV (610) is opened to switch the driving mode, the refrigerant pressure difference between the high-pressure gas pipe (311) connected to the first side of the heating EEV (610) and the refrigerant pipe (312) connected to the second side of the heating EEV (610) can be reduced. Meanwhile, the air conditioner (1000) controls the opening of the heating EEV (610), which is used as a pressure-balanced EEV, to a minimum opening, thereby preventing or reducing the rapid change in refrigerant pressure on both sides of the heating EEV (610).

[0110] In the heating operation stage (604), the air conditioner (1000) can start the heating operation of the indoor unit (200) by controlling the heating EEV (610) to open to a higher opening than the minimum opening while the refrigerant pressure in the indoor heat exchanger (210) and the refrigerant pipe (312) is increased.

[0111] An air conditioner (1000) according to one embodiment of the present disclosure can prevent or reduce problems such as noise, shock, and refrigerant pipe damage that occur when the cooling EEV (620) is immediately closed and the heating EEV (610) is opened when switching from cooling operation to heating operation.

[0112] Additionally, in the pressure equilibration step (603) according to one embodiment of the present disclosure, the air conditioner (1000) may be controlled to close the cooling EEV (620). However, if there is a malfunction in the cooling EEV (620) of the EEV type, the cooling EEV (620) may be slightly opened. In this case, the refrigerant in the refrigerant pipe (312) may escape toward the cooling EEV (620), and the refrigerant pressure in the refrigerant pipe (312) may not increase or may increase less. Accordingly, the refrigerant pressure difference between the high-pressure section and the low-pressure section on both sides of the heating EEV (610) may not decrease. Consequently, if the heating EEV (610) is opened while the refrigerant pressure difference is not decreased, significant noise and vibration may occur in the indoor unit (200) and the mode change control device (300b). An air conditioner (1000) according to one embodiment of the present disclosure may, after performing a pressure equilibration step (603), determine whether the pressure equilibration was successfully performed and then determine whether to perform a heating operation step (604). This is explained in FIGS. 11 and 12.

[0113] FIG. 7a is a diagram illustrating a process in which an air conditioner according to one embodiment of the present disclosure switches from cooling operation to heating operation. FIG. 7b is a table illustrating valve operation when the air conditioner of FIG. 7a switches from cooling operation to heating operation.

[0114] In the heating operation stage (701), the air conditioner (1000) can perform heating operation by controlling the heating EEV (610) and the indoor EEV (220) to open. High-pressure gaseous refrigerant delivered through the high-pressure gas pipe (311) is delivered to the heating EEV (610), and low-pressure liquid refrigerant can exit through the liquid pipe (316). This corresponds to the heating operation (202) of FIG. 2B. Here, the heating EEV (610) may be open to an opening higher than the minimum opening. The cooling EEV (620) may be closed.

[0115] An air conditioner (1000) according to one embodiment of the present disclosure may operate in the order of a heating stop step (702), a pressure equalization step (703), and a cooling operation step (704) based on a command to switch from a heating operation to a cooling operation. Before opening the cooling EEV (620), the air conditioner (1000) may equalize the pressure between both sides of the cooling EEV (620).

[0116] In the heating stop phase (702), the air conditioner (1000) can stop the heating operation by controlling the heating EEV (610) and the indoor EEV (220) to close. When the operation of the indoor unit (200) is stopped, the refrigerant flow of the indoor unit (200) can be blocked. In this case, the refrigerant pipe (312) can form a high-pressure section.

[0117] In the pressure-balancing stage (703) through the low-pressure reduction of the indoor unit (200), the air conditioner (1000) can control the cooling EEV (620) to open so that the pressure of the refrigerant flowing through the indoor unit (200) can be lowered. When the air conditioner (1000) is in a stopped state, the cooling EEV (620) can be used as a pressure-balancing EEV by opening the cooling EEV (620) to a minimum opening. When the cooling EEV (620) is opened to a minimum opening, gaseous refrigerant in a low-pressure state can flow through the low-pressure gas pipe (314) to the refrigerant pipe (312) and the indoor heat exchanger (210). Accordingly, the pressure of the high-pressure section formed in the refrigerant pipe (312) and the indoor heat exchanger (210) can be reduced. Ultimately, when the cooling EEV (620) is opened to switch the driving mode, the refrigerant pressure difference between the low-pressure gas pipe (314) connected to the first side of the cooling EEV (620) and the refrigerant pipe (312) connected to the second side of the cooling EEV (620) can be reduced. Meanwhile, the air conditioner (1000) can control the opening of the cooling EEV (620), which is used as a pressure-balanced EEV, to a minimum opening, thereby preventing or reducing the rapid change in refrigerant pressure on both sides of the cooling EEV (620).

[0118] In the cooling operation stage (704), the air conditioner (1000) can start cooling operation of the indoor unit (200) by opening the cooling EEV (620) and controlling the indoor EEV (220) to open when the refrigerant pressure in the indoor heat exchanger (210) and the refrigerant pipe (312) is reduced. Here, the heating EEV (610) may be in a closed state.

[0119] An air conditioner (1000) according to one embodiment of the present disclosure can prevent or reduce problems such as noise, shock, and refrigerant pipe damage that occur when the heating EEV (610) is immediately closed and the cooling EEV (620) is opened when switching from heating operation to cooling operation.

[0120] Additionally, in the pressure equilibration step (703) according to one embodiment of the present disclosure, the air conditioner (1000) may be controlled to close the heating EEV (610). However, if there is a malfunction in the heating EEV (610) of the EEV type, the heating EEV (610) may be slightly opened. In this case, high-pressure refrigerant may flow into the refrigerant pipe (312) through the heating EEV (610), so that the refrigerant pressure in the refrigerant pipe (312) does not decrease or decreases less. Accordingly, the refrigerant pressure difference between the high-pressure section and the low-pressure section on both sides of the cooling EEV (620) may not decrease. Consequently, if the cooling EEV (620) is opened while the refrigerant pressure difference is not decreased, significant noise and vibration may occur in the indoor unit (200) and the mode change control device (300b). An air conditioner (1000) according to one embodiment of the present disclosure may, after performing a pressure equilibration step (703), determine whether the pressure equilibration was successfully performed and then determine whether to perform a cooling operation step (704). This is explained in FIGS. 11 and 13.

[0121] Hereinafter, with reference to FIGS. 8a to 9b, an air conditioner (1000) including a mode change control device (300c) according to one embodiment of the present disclosure will be described.

[0122] FIG. 8a is a diagram illustrating a process in which an air conditioner according to one embodiment of the present disclosure switches from cooling operation to heating operation. FIG. 8b is a table illustrating valve operation when the air conditioner of FIG. 8a switches from cooling operation to heating operation.

[0123] An air conditioner (1000) according to one embodiment of the present disclosure may include an outdoor unit (100), an indoor unit (200), and a mode change control device (300c). The mode change control device (300c) may include a heating main valve (810), a cooling main valve (820), a heating sub valve (830), and a cooling sub valve (840). The mode change control device (300c) of FIGS. 8A and 9A may correspond to the mode change control device (300) of FIGS. 1 to 2B. The heating main valve (810) of FIGS. 8A and 9A may correspond to the heating valve (310) of FIG. 2A. The cooling main valve (820) of FIGS. 8A and 9A may correspond to the cooling valve (320) of FIG. 2A. The mode change control device (300c) of FIGS. 8a and 9a may further include a heating sub-valve (830) and a cooling sub-valve (840) compared to the mode change control device (300) of FIGS. 1 to 2b. The mode change control device (300c) differs from the mode change control device (300a) of FIGS. 4a and 5a in that it further includes a heating sub-valve (830). The mode change control device (300c) differs from the mode change control device (300b) of FIGS. 6a and 7a in that it further includes a heating sub-valve (830) and a cooling sub-valve (840).

[0124] According to one embodiment of the present disclosure, the heating main valve (810) and the cooling main valve (820) may be solenoid-type valves. The heating main valve (810) and the cooling main valve (820) may completely open or completely close the flow of a specific section through ON control or OFF control. However, not limited thereto, the heating main valve (810) and the cooling main valve (820) may be EEV-type valves for controlling the rated flow rate. The heating main valve (810) and the cooling main valve (820) may correspond to the heating main valve (410) and the cooling main valve (420) of FIG. 4a.

[0125] The heating sub-valve (830) and the cooling sub-valve (840) may be EEV type valves. The heating sub-valve (830) and the cooling sub-valve (840) may be used as pressure-balanced EEVs of the air conditioner (1000) when switching between operating modes. For example, the heating sub-valve (830) may be used as a pressure-balanced EEV when switching from cooling operation to heating operation. This is explained in the pressure-balanced step (803) of FIG. 8a. For example, the cooling sub-valve (840) may be used as a pressure-balanced EEV when switching from heating operation to cooling operation. This is explained in the pressure-balanced step (903) of FIG. 9a.

[0126] In the cooling operation stage (801), the air conditioner (1000) can perform cooling operation by controlling the cooling main valve (820) and the indoor EEV (220) to open. High-pressure liquid refrigerant is delivered to the indoor EEV (220) through the liquid pipe (316), and low-pressure gaseous refrigerant can exit through the low-pressure gas pipe (314). This corresponds to the cooling operation (201) of FIG. 2B. Additionally, in the cooling operation stage (801), since the cooling sub-valve (840) is open, low-pressure gaseous refrigerant can also exit through the cooling sub-valve (840) to the low-pressure gas pipe (314). Here, the heating main valve (810) and the heating sub-valve (830) may be in a closed state.

[0127] An air conditioner (1000) according to one embodiment of the present disclosure may operate in the order of a cooling stop step (802), a pressure equalization step (803), and a heating operation step (804) based on a command to switch from cooling operation to heating operation. Before opening the heating main valve (810), the air conditioner (1000) may equalize the pressure between both sides of the heating main valve (810).

[0128] In the cooling stop step (802), the air conditioner (1000) can stop cooling operation by controlling the cooling main valve (820), cooling sub valve (840), and indoor EEV (220) to close. When the operation of the indoor unit (200) is stopped, the refrigerant flow of the indoor unit (200) can be blocked. In this case, the refrigerant pipe (312) can form a low-pressure section.

[0129] In the pressure-balancing stage (803) through the high-pressure operation of the indoor unit (200), the air conditioner (1000) can control the heating sub-valve (830) to open, thereby increasing the pressure of the refrigerant flowing through the indoor unit (200). When the air conditioner (1000) is stopped from operation, the heating sub-valve (830) in the open state can be used as a pressure-balancing EEV. When the heating sub-valve (830) is opened, the gaseous refrigerant in a high-pressure state can flow through the high-pressure gas pipe (311) to the refrigerant pipe (312) and the indoor heat exchanger (210). Accordingly, the pressure of the low-pressure section formed in the refrigerant pipe (312) and the indoor heat exchanger (210) can be increased. Ultimately, when the heating main valve (810) is opened to switch the operating mode, the refrigerant pressure difference between the high-pressure gas pipe (311) connected to the first side of the heating main valve (810) and the refrigerant pipe (312) connected to the second side of the heating main valve (810) can be reduced.

[0130] In the heating operation stage (804), the air conditioner (1000) can start the heating operation of the indoor unit (200) by controlling the heating main valve (810) to open to an opening higher than the minimum opening while the refrigerant pressure in the indoor heat exchanger (210) and the refrigerant pipe (312) is increased.

[0131] An air conditioner (1000) according to one embodiment of the present disclosure can prevent or reduce problems such as noise, shock, and refrigerant pipe damage that occur when the cooling main valve (820) is immediately closed and the heating main valve (810) is opened when switching from cooling operation to heating operation.

[0132] Additionally, in the pressure balancing step (803) according to one embodiment of the present disclosure, the air conditioner (1000) can be controlled to close the cooling EEV (620).

[0133] Additionally, in the pressure balancing step (803) according to one embodiment of the present disclosure, the air conditioner (1000) may be controlled to close the cooling sub-valve (840). However, if there is a failure of the cooling sub-valve (840) of the EEV type, the cooling sub-valve (840) may be slightly opened. In this case, the refrigerant in the refrigerant pipe (312) may escape toward the cooling sub-valve (840), and the refrigerant pressure in the refrigerant pipe (312) may not increase or may increase less. Accordingly, the refrigerant pressure difference between the high-pressure section and the low-pressure section on both sides of the heating main valve (810) may not decrease. Consequently, if the heating main valve (810) is opened while the refrigerant pressure difference is not decreased, significant noise and vibration may occur in the indoor unit (200) and the mode change control device (300c). An air conditioner (1000) according to one embodiment of the present disclosure may, after performing a pressure equilibration step (803), determine whether the pressure equilibration was successfully performed and then determine whether to perform a heating operation step (804). This is explained in FIGS. 11 and 12.

[0134] FIG. 9a is a diagram illustrating a process in which an air conditioner according to one embodiment of the present disclosure switches from cooling operation to heating operation. FIG. 9b is a table illustrating valve operation when the air conditioner of FIG. 9a switches from cooling operation to heating operation.

[0135] In the heating operation stage (901), the air conditioner (1000) can perform heating operation by controlling the heating main valve (810) and the indoor EEV (220) to open. High-pressure gaseous refrigerant delivered through the high-pressure gas pipe (311) is delivered to the heating main valve (810), and low-pressure liquid refrigerant can exit through the liquid pipe (316). This corresponds to the heating operation (202) of FIG. 2B. Additionally, in the heating operation stage (901), since the heating sub-valve (830) is open, high-pressure gaseous refrigerant can also be delivered to the high-pressure gas pipe (311) through the heating sub-valve (830). The cooling main valve (820) and the cooling sub-valve (840) may be closed.

[0136] An air conditioner (1000) according to one embodiment of the present disclosure may operate in the order of a heating stop step (902), a pressure equalization step (903), and a cooling operation step (904) based on a command to switch from a heating operation to a cooling operation. Before opening the cooling main valve (820), the air conditioner (1000) may equalize the pressure between both sides of the cooling main valve (820).

[0137] In the heating stop phase (902), the air conditioner (1000) can stop the heating operation by controlling the heating main valve (810), the heating sub valve (830), and the indoor EEV (220) to close. When the operation of the indoor unit (200) is stopped, the refrigerant flow of the indoor unit (200) can be blocked. In this case, the refrigerant pipe (312) can form a high-pressure section.

[0138] In the pressure equilibrium stage (903) through the low-pressure reduction of the indoor unit (200), the air conditioner (1000) can control the cooling sub-valve (840) to open so as to lower the pressure of the refrigerant flowing to the indoor unit (200). This can correspond to the pressure equilibrium stage (503) of FIG. 5a.

[0139] In the cooling operation stage (904), the air conditioner (1000) can start cooling operation of the indoor unit (200) by opening the cooling main valve (820) and controlling the indoor EEV (220) to open when the refrigerant pressure in the indoor heat exchanger (210) and the refrigerant pipe (312) is reduced. Here, the heating main valve (810) may be in a closed state.

[0140] An air conditioner (1000) according to one embodiment of the present disclosure can prevent or reduce problems such as noise, shock, and refrigerant pipe damage that occur when the heating main valve (810) is immediately closed and the cooling main valve (820) is opened when switching from heating operation to cooling operation.

[0141] Additionally, in the pressure balancing step (903) according to one embodiment of the present disclosure, the air conditioner (1000) may be controlled to close the heating sub-valve (830). However, if there is a malfunction in the heating sub-valve (830) of the EEV type, the heating sub-valve (830) may be slightly opened. In this case, high-pressure refrigerant may flow into the refrigerant pipe (312) through the heating sub-valve (830), so that the refrigerant pressure in the refrigerant pipe (312) does not decrease or decreases less. Accordingly, the refrigerant pressure difference between the high-pressure section and the low-pressure section on both sides of the cooling main valve (820) may not decrease. Consequently, if the cooling main valve (820) is opened while the refrigerant pressure difference is not decreased, significant noise and vibration may occur in the indoor unit (200) and the mode change control device (300c). An air conditioner (1000) according to one embodiment of the present disclosure may, after performing a pressure equilibration step (903), determine whether the pressure equilibration was successfully performed and then determine whether to perform a cooling operation step (904). This is explained in FIGS. 11 and 13.

[0142] FIG. 10 is a block diagram of an indoor unit, a mode change control device, and an outdoor unit according to one embodiment of the present disclosure.

[0143] Referring to FIG. 10, an air conditioner (1000) according to one embodiment of the present disclosure may include an outdoor unit (100), an indoor unit (200), and a mode change control device (300). The outdoor unit (100) and the indoor unit (200), the outdoor unit (100) and the mode change control device (300), and the indoor unit (200) and the mode change control device (300) may communicate bidirectionally. The outdoor unit (100), the indoor unit (200), and the mode change control device (300) may transmit and receive various signals generated during the operation of the air conditioner (1000).

[0144] Each of the outdoor unit communication unit (1030), indoor unit communication unit (2030), and central communication unit (3030) according to one embodiment of the present disclosure includes various communication circuits and can exchange various data with components within the air conditioner (1000) or external devices according to the control of each of the outdoor unit processor (1010), indoor unit processor (2010), and central processor (3010). Each of the outdoor unit communication unit (1030), indoor unit communication unit (2030), and central communication unit (3030) may include a port for connecting a wired cable that performs wired communication between the outdoor unit (100), indoor unit (200), and mode change control device (300). Each of the outdoor unit communication unit (1030), indoor unit communication unit (2030), and central communication unit (3030) can transmit a received control signal to each of the connected outdoor unit processor (1010), indoor unit processor (2010), and central processor (3010).

[0145] An outdoor unit (100) according to one embodiment of the present disclosure may include an outdoor unit processor (1010) (e.g., including a processing circuit), an outdoor unit memory (1020), and an outdoor unit communication unit (1030). However, not all components shown in FIG. 10 are essential components. An outdoor unit (100) may be implemented with more components than those shown in FIG. 10, or with fewer components.

[0146] The outdoor unit processor (1010) includes various processing circuits and can control the overall operation of the outdoor unit (100). The outdoor unit processor (1010) can be electrically connected to the components of the outdoor unit (100) and can control the operation of each component. The outdoor unit processor (1010) can communicate with the indoor unit (200) or the mode change control device (300) through the outdoor unit communication unit (1030). The outdoor unit processor (1010) can control the components of the outdoor unit (100) based on information regarding user input received from the indoor unit (200) or the mode change control device (300). For example, the outdoor unit processor (1010) can control the operation of the compressor, outdoor heat exchanger, expansion device, flow path switching valve, accumulator, or outdoor circulation fan based on a control signal received through the outdoor unit communication unit (1030). Under the control of the outdoor unit processor (1010), refrigerant can circulate along a refrigerant circulation circuit including a compressor, a flow path switching valve, an outdoor heat exchanger, an expansion valve, and an indoor heat exchanger.

[0147] The outdoor unit memory (1020) can store a program for processing and controlling the outdoor unit processor (1010), and can also store data that is input to the outdoor unit (100) or output from the outdoor unit (100).

[0148] An indoor unit (200) according to one embodiment of the present disclosure may include an indoor unit processor (2010), an indoor unit memory (2020), an indoor unit communication unit (2030), an indoor unit sensor (2040), an input / output interface (2050), an indoor unit driving unit (2060), and an indoor EEV (220). However, not all components shown in FIG. 10 are essential components. The indoor unit (200) may be implemented with more components than those shown in FIG. 10, or with fewer components.

[0149] The indoor unit processor (2010) includes various processing circuits and can control the overall operation of the indoor unit (200). For example, the indoor unit processor (2010) can control the indoor unit communication unit (2030), indoor unit sensor (2040), input / output interface (2050), and indoor unit driving unit (2060) by executing a program stored in the indoor unit memory (2020). Additionally, the indoor unit processor (2010) can generate a control signal for adjusting the opening of the indoor EEV (220) and a control signal for controlling the indoor blower fan.

[0150] The indoor unit processor (2010) can obtain user input from a user terminal through the indoor unit communication unit (2030), and can obtain user input directly or through a remote controller through the input / output interface (2050). The indoor unit processor (2010) can control the components of the indoor unit (200) so that the operation of the air conditioner (1000) corresponding to the received user input is performed. The indoor unit processor (2010) can generate a control signal corresponding to the user input and transmit the generated control signal to the outdoor unit (100) or to the mode change control device (300). In addition, for example, the indoor unit processor (2010) can transmit a sensing value detected from the indoor unit sensor (2040) to the outdoor unit (100) or the mode change control device (300) through the indoor unit communication unit (2030). The indoor unit processor (2010) can transmit the detected error code to the outdoor unit (100) or the mode change control device (300) through the indoor unit communication unit (2030).

[0151] The indoor unit memory (2020) can store a program for processing and controlling the indoor unit processor (2010), and can also store data that is input to the indoor unit (200) or output from the indoor unit (200).

[0152] The indoor unit sensor (2040) may include a temperature sensor placed in a predetermined space inside or outside the housing of the indoor unit (200). For example, the indoor unit sensor (2040) may include a refrigerant temperature sensor that detects the inlet, middle, and / or outlet temperature of a refrigerant pipe passing through an indoor heat exchanger. For example, the indoor unit sensor (2040) may include a refrigerant pressure sensor that detects the inlet, middle, and / or outlet pressure of a refrigerant pipe passing through an indoor heat exchanger. For example, the refrigerant temperature sensor may include the inlet temperature sensor (241) and the outlet temperature sensor (242) of FIG. 2A.

[0153] The input / output interface (2050) includes various circuits and may include an input interface and an output interface. The input / output interface (2050) may be electrically connected to the indoor unit processor (2010). This is further explained in FIG. 16.

[0154] The indoor unit driving unit (2060) includes various circuits and can drive the indoor EEV (220) based on a control signal from the indoor unit processor (2010). For example, the indoor unit driving unit (2060) can open and close the indoor EEV (220) by controlling the opening of the indoor EEV (220).

[0155] A mode change control device (300) according to one embodiment of the present disclosure may include a central processor (3010), a central memory (3020), a central communication unit (3030), an input / output interface (3040), a central driving unit (3050), a heating valve (310), and a cooling valve (320). However, not all components shown in FIG. 10 are essential components. The mode change control device (300) may be implemented with more components than those shown in FIG. 10, or with fewer components.

[0156] The central processor (3010) includes various processing circuits and can control the overall operation of the mode change control device (300). For example, the central processor (3010) can control the central communication unit (3030), the input / output interface (3040), and the central driving unit (3050) by executing a program stored in the central memory (3020). Additionally, the central processor (3010) can generate control signals for controlling the heating valve (310) and the cooling valve (320).

[0157] The central processor (3010) can communicate with the indoor unit (200) or the outdoor unit (100) through the central communication unit (3030). The central processor (3010) can control the configurations of the mode change control device (300) based on information regarding user input received from the indoor unit (200) or the outdoor unit (100). For example, when the central processor (3010) receives a control signal from the indoor unit (200) that corresponds to a user input selecting an operation mode such as cooling operation, heating operation, blower operation, defrosting operation, or dehumidification operation, the central processor (3010) can control the configurations of the mode change control device (300) so that the operation of the air conditioner (1000) corresponding to the selected operation mode is performed. For example, the central processor (3010) can control the operation of the supercooler (440-1, 440-2, ..., 440-n) and supercooling EEV (450) of FIG. 3, the heating main valve (410), cooling main valve (420), and cooling sub-valve (430) of FIG. 4a, the heating EEV (610) and cooling EEV (620) of FIG. 6a, and the heating main valve (810), cooling main valve (820), heating sub-valve (830), and cooling sub-valve (840) of FIG. 8a, based on a control signal received through the central communication unit (3030).

[0158] The input / output interface (3040) includes various circuits and may include an input interface including switches, buttons, etc. for receiving control commands for the mode change control device (300) from a user or administrator. The input / output interface (3040) may include an output interface including a display panel, etc. for outputting the operating status of the mode change control device (300). For example, the input / output interface (3040) may receive control commands for switching the operating mode from a user or administrator. For example, the input / output interface (3040) may display an error code due to a valve failure.

[0159] The central drive unit (3050) includes various circuits and can drive the heating valve (310) and the cooling valve (320) under the control of the central processor (3010). For example, the central drive unit (3050) can generate a driving current to open and close the heating valve (310) and the cooling valve (320) and provide it to the heating valve (310) and the cooling valve (320).

[0160] The central memory (3020) can store programs and data related to the operation of the mode change control device (300), and can also store data that is input to or output from the mode change control device (300).

[0161] The pressure-balancing control method and pressure-balancing control error detection method according to one embodiment of the present disclosure may be performed by the outdoor unit (100), the indoor unit (200), and the mode change control device (300) separately, or each of the outdoor unit (100), the indoor unit (200), and the mode change control device (300) may perform individually.

[0162] At least one of an outdoor unit processor (1010), an indoor unit processor (2010), or a central processor (3010) according to one embodiment of the present disclosure performs a first operation corresponding to either a cooling operation or a heating operation, stops the first operation based on a command to switch to a second operation corresponding to the other of the cooling operation or the heating operation, performs pressure-balancing control to reduce the refrigerant pressure difference between both sides of a switching valve for the second operation while the first operation is stopped, determines whether the refrigerant pressure difference is reduced, and determines whether to perform the second operation based on the result of the determination.

[0163] For example, the indoor unit processor (2010) can perform a first operation corresponding to either a cooling operation or a heating operation by opening the indoor EEV (220). The indoor unit processor (2010) can obtain a command to switch from the first operation to a second operation corresponding to either a cooling operation or a heating operation through an input interface. Based on the switching command, the indoor unit processor (2010) can stop the first operation by controlling the indoor EEV (220) to close. The indoor unit processor (2010) can transmit a control signal corresponding to the switching command to the outdoor unit (100) and the mode change control device (300) through the indoor unit communication unit (2030). While the first operation is stopped, the indoor unit processor (2010) can determine whether the refrigerant pressure difference between both sides of the switching valve for the second operation is reduced. The indoor unit processor (2010) can determine whether to perform a second operation by opening the indoor EEV (220) based on the result of the judgment.

[0164] For example, the central processor (3010) can receive a control signal corresponding to a switching command from the indoor unit (200) through the central communication unit (3030). The central processor (3010) can perform pressure-balancing control based on the switching command.

[0165] For example, at least one of the indoor unit processor (2010) or the central processor (3010) can control the pressure-balanced EEV to open for pressure-balanced control. For example, if the pressure-balanced EEV is provided in the indoor unit (200), the indoor unit processor (2010) can control the pressure-balanced EEV to open while the first operation is stopped. For example, if the pressure-balanced EEV is provided in the mode change control device (300), the central processor (3010) can control the pressure-balanced EEV to open while the first operation is stopped.

[0166] For example, the indoor unit processor (2010) can detect a pressure-balancing control error. The indoor unit processor (2010) can obtain a first refrigerant temperature before pressure-balancing control is performed through a refrigerant temperature sensor. Here, the first refrigerant temperature may be data sensed at a time point before pressure-balancing control is performed while the first operation is stopped. The indoor unit processor (2010) can obtain a second refrigerant temperature after pressure-balancing control is performed through a refrigerant temperature sensor. The indoor unit processor (2010) can determine whether the temperature difference between the first refrigerant temperature and the second refrigerant temperature corresponds to a predetermined condition. When the indoor unit processor (2010) determines that the temperature difference corresponds to a predetermined condition, it can control the indoor EEV (220) to open and transmit an error code to the mode change control device (300) through the indoor unit communication unit (2030). The indoor unit processor (2010) can control the indoor EEV (220) to be closed as it determines that the temperature difference does not correspond to a predetermined condition. For example, the indoor unit processor (2010) can determine that the temperature difference corresponds to a predetermined condition if the temperature difference is greater than a predetermined value.

[0167] FIG. 11 is a flowchart illustrating a method for detecting a pressure-balancing control error when switching the operating mode of an air conditioner according to one embodiment of the present disclosure. FIG. 11 is explained in conjunction with FIG. 10.

[0168] Referring to FIG. 11, in step 1110, the air conditioner (1000) may perform a first operation. For example, if the first operation is a cooling operation, the second operation may be a heating operation. For example, if the first operation is a heating operation, the second operation may be a cooling operation. For example, step 1110 may correspond to at least one of the cooling operation step (401) of FIG. 4a, the heating operation step (501) of FIG. 5a, the cooling operation step (601) of FIG. 6a, the heating operation step (701) of FIG. 7a, the cooling operation step (801) of FIG. 8a, and the heating operation step (901) of FIG. 9a.

[0169] In step 1120, the air conditioner (1000) can stop the first operation based on a command to switch the operation mode from the first operation to the second operation.

[0170] An air conditioner (1000) according to one embodiment of the present disclosure may receive user input corresponding to a command to switch the operation mode from a first operation to a second operation. User input corresponding to the operation mode switching command may include an operation mode setting input for selecting cooling operation or heating operation, or an indoor temperature setting input for setting the indoor temperature. For example, an indoor unit (200) may receive user input corresponding to the operation mode switching command. However, it is not limited thereto, and user input corresponding to the operation mode switching command may be received by a mode change control device (300) or an outdoor unit (100). This is further explained in FIG. 14.

[0171] An air conditioner (1000) according to one embodiment of the present disclosure may stop a first operation based on a control signal corresponding to an operation mode switching command. For example, an indoor unit (200) may be controlled to close an indoor EEV (220) based on a control signal corresponding to an operation mode switching command. For example, a mode change control device (300) may be controlled to close a heating valve (310) based on a control signal corresponding to a switching command from heating operation to cooling operation. The mode change control device (300) may be controlled to stop the heating operation. For example, the mode change control device (300) may be controlled to close a cooling valve (320) based on a control signal corresponding to a switching command from cooling operation to heating operation. The mode change control device (300) may be controlled to stop the cooling operation.

[0172] For example, step 1120 may correspond to at least one of the cooling stop step (402) of FIG. 4a, the heating stop step (502) of FIG. 5a, the cooling stop step (602) of FIG. 6a, the heating stop step (702) of FIG. 7a, the cooling stop step (802) of FIG. 8a, and the heating stop step (902) of FIG. 9a.

[0173] In step 1130, the air conditioner (1000) can perform pressure balancing control while the first operation is stopped. The air conditioner (1000) can perform control to balance the refrigerant pressure difference on both sides of the transfer valve for the second operation while the first operation is stopped.

[0174] For example, the air conditioner (1000) can control the pressure-balanced EEV while the heating operation or cooling operation is stopped. For example, step 1130 may correspond to at least one of the pressure-balanced step (403) of FIG. 4a, the pressure-balanced step (503) of FIG. 5a, the pressure-balanced step (603) of FIG. 6a, the pressure-balanced step (703) of FIG. 7a, the pressure-balanced step (803) of FIG. 8a, and the pressure-balanced step (903) of FIG. 9a.

[0175] In step 1140, the air conditioner (1000) can determine whether the refrigerant pressure difference between both sides of the transfer valve is reduced. In one embodiment of the present disclosure, the air conditioner (1000) can determine whether to perform a switched operation based on the result of determining whether the refrigerant pressure difference between both sides of the transfer valve is reduced. Here, the transfer valve for determining whether the refrigerant pressure difference is reduced may be a transfer valve for a second operation. For example, if the first operation is a cooling operation and the second operation is a heating operation, the transfer valve may be a heating valve (310). For example, if the first operation is a heating operation and the second operation is a cooling operation, the transfer valve may be a cooling valve (320).

[0176] The air conditioner (1000) can determine whether pressure balancing according to step 1130 has been performed normally in order to prevent or reduce noise, vibration, or damage caused by the refrigerant pressure difference on both sides of the switching valve when the switching valve is suddenly opened according to the operation mode switching. For example, the air conditioner (1000) can identify the range of change in the refrigerant pressure flowing to the indoor unit (200) side before and after pressure balancing control to determine whether pressure balancing control has been performed normally. For example, if the pressure of the refrigerant flowing to the indoor unit (200) side changes significantly before and after pressure balancing control, the air conditioner (1000) can identify that the refrigerant pressure difference has been reduced normally.

[0177] In one embodiment of the present disclosure, the air conditioner (1000) may use a refrigerant temperature sensor that detects the temperature of a refrigerant pipe passing through an indoor heat exchanger to indirectly determine an increase or decrease in the refrigerant pressure formed on the indoor unit (200) side of the switching valve. For example, as the refrigerant pressure of the indoor heat exchanger increases or decreases, the refrigerant temperature of the indoor heat exchanger may increase or decrease. The air conditioner (1000) may determine whether the pressure difference between both sides of the switching valve decreases through the refrigerant temperature sensor. For example, the air conditioner (1000) may detect the refrigerant temperature at a first time point using the refrigerant temperature sensor before step 1130. The air conditioner (1000) may detect the refrigerant temperature at a second time point using the refrigerant temperature sensor after step 1130. The air conditioner (1000) may determine whether the temperature difference between the refrigerant temperature at the first time point and the refrigerant temperature at the second time point corresponds to a predetermined condition. For example, the air conditioner (1000) may determine that the range of change in refrigerant pressure is large if the temperature difference between the refrigerant temperature at the first time point and the refrigerant temperature at the second time point is greater than a defined value. The air conditioner (1000) may determine that the refrigerant pressure difference has decreased if the range of change in refrigerant pressure on the indoor unit (200) side is large. Here, the defined value may be a reference temperature for determining whether the refrigerant pressure has changed normally according to pressure-balancing control. Specific applications for each operating mode are described in FIGS. 12 and 13. The air conditioner (1000) may be controlled to stop operation if it is determined that the temperature of the indoor heat exchanger has not reached a certain level even after pressure-balancing control is completed. The air conditioner (1000) may switch the operating mode only when the temperature of the indoor heat exchanger reaches a certain level after pressure-balancing control is completed.

[0178] Alternatively, in one embodiment of the present disclosure, the air conditioner (1000) can directly determine whether the range of change in refrigerant pressure on the indoor unit (200) side before and after pressure equilibration is large by using a refrigerant pressure sensor that detects the pressure of a refrigerant pipe passing through an indoor heat exchanger. For example, the air conditioner (1000) can detect the refrigerant pressure at a first time point using the refrigerant pressure sensor before step 1130, and detect the refrigerant pressure at a second time point using the refrigerant pressure sensor after step 1130. The air conditioner (1000) can determine that the range of change in refrigerant pressure is large if the pressure difference between the refrigerant pressure at the first time point and the refrigerant pressure at the second time point is greater than a predetermined value. Here, the predetermined value may be a reference pressure for determining whether the refrigerant pressure has changed normally according to pressure equilibration control.

[0179] In one embodiment of the present disclosure, a predetermined value may be determined based on the refrigerant pressure of the outdoor unit (100). For example, the temperature change of the indoor heat exchanger may vary depending on the refrigerant pressure of the outdoor unit (100). If the refrigerant pressure of the outdoor unit (100) is high, the temperature of the indoor heat exchanger may be relatively high. Also, if the refrigerant pressure of the outdoor unit (100) is low, the temperature of the indoor heat exchanger may be relatively low. Accordingly, depending on the refrigerant pressure of the outdoor unit (100), the range of temperature change between the refrigerant temperature at a first time point and the refrigerant temperature at a second time point may differ. Depending on the refrigerant pressure of the outdoor unit (100), the range of pressure change between the refrigerant pressure at a first time point and the refrigerant pressure at a second time point may also differ. Since the air conditioner (1000) can determine a predetermined value differently depending on the refrigerant pressure of the outdoor unit (100), it can more accurately determine whether the valve is malfunctioning.

[0180] Alternatively, in one embodiment of the present disclosure, the air conditioner (1000) may directly detect the refrigerant pressure on both sides of the switching valve after step 1130 to determine whether pressure-balancing control has been performed normally. For example, the air conditioner (1000) may detect the refrigerant pressure on the second side of the switching valve (indoor unit (200) side) through a refrigerant pressure sensor. If the air conditioner (1000) knows the refrigerant pressure value on the first side of the switching valve (outdoor unit (100) side), it may determine whether the refrigerant pressure on the first side and the refrigerant pressure on the second side are close to each other.

[0181] In step 1150, if the air conditioner (1000) determines that the refrigerant pressure difference on both sides of the switching valve has decreased, it may perform a second operation.

[0182] For example, step 1150 may correspond to at least one of the heating operation step (404) of FIG. 4a, the cooling operation step (504) of FIG. 5a, the heating operation step (604) of FIG. 6a, the cooling operation step (704) of FIG. 7a, the heating operation step (804) of FIG. 8a, and the cooling operation step (904) of FIG. 9a.

[0183] In step 1160, if the air conditioner (1000) determines that the refrigerant pressure difference on both sides of the switching valve has not decreased, it can transmit an error code and stop operation.

[0184] For example, if the air conditioner (1000) determines that the refrigerant pressure difference on both sides of the switching valve has not decreased, it can identify that there is a failure of the EEV type valve included in the air conditioner (1000). The air conditioner (1000) can determine that pressure balancing was not performed normally due to the valve failure.

[0185] For example, the indoor unit (200) can identify a valve failure and generate an error code. The error code may be information indicating that pressure balancing was not performed normally due to a valve failure of the EEV type included in the air conditioner (1000).

[0186] For example, the indoor unit (200) can transmit an error code to the mode change control device (300) through the indoor unit communication unit (2030). The indoor unit (200) can be controlled to stop the operation of the indoor unit (200). The indoor unit (200) can display the error code through a display. The mode change control device (300) can be controlled to stop the operation of the mode change control device (300) based on the error code received from the indoor unit (200) through the central communication unit (3030).

[0187] Accordingly, the air conditioner (1000) can prevent or reduce noise, vibration, and shock occurring in the air conditioner (1000) when switched operation is performed in a state where pressure balancing is not performed normally due to a failure of the EEV type valve included in the air conditioner (1000).

[0188] Here, the operations of steps 1140 to 1160 are exemplified as being performed by the indoor unit (200), but are not limited thereto. For example, some or all of the operations of steps 1140 to 1160 may be performed by the outdoor unit (100), the indoor unit (200), and the mode change control device (300), or each of the outdoor unit (100), the indoor unit (200), and the mode change control device (300) may perform them individually.

[0189] FIG. 12 is a flowchart illustrating a method for detecting a pressure-balancing control error when an air conditioner according to one embodiment of the present disclosure switches from cooling operation to heating operation. FIG. 12 is explained in conjunction with FIG. 10.

[0190] Referring to FIG. 12, in step 1210, the indoor unit (200) and the mode change control device (300) can perform cooling operation. For example, step 1210 may include steps 1213 and 1217. In step 1213, the indoor unit (200) can be controlled to open the indoor EEV (220) for cooling operation. In step 1217, the mode change control device (300) can be controlled to open the cooling valve (320) for cooling operation.

[0191] Here, step 1210 may correspond to at least one of the cooling operation step (401) of FIG. 4a, the cooling operation step (601) of FIG. 6a, or the cooling operation step (801) of FIG. 8a. The cooling valve (320) may correspond to at least one of the cooling main valve (420) of FIG. 4a, the cooling EEV (620) of FIG. 6a, or the cooling main valve (820) of FIG. 8a. Meanwhile, the heating valve (310) may correspond to at least one of the heating main valve (410) of FIG. 5a, the heating EEV (610) of FIG. 7a, or the heating main valve (810) of FIG. 9a. Step 1210 may correspond to step 1110 of FIG. 11.

[0192] In step 1220, the indoor unit (200) can receive user input corresponding to an operation mode switching command. For example, if the indoor unit (200) receives a heating operation setting input while performing cooling operation, it can generate a control signal to perform a switching operation from cooling operation to heating operation. In step 1225, the indoor unit (200) can transmit a control signal corresponding to the operation mode switching command to the mode change control device (300) through the indoor unit communication unit (2030). The mode change control device (300) can receive a control signal corresponding to the operation mode switching command from the indoor unit (200) through the central communication unit (3030).

[0193] In step 1230, the indoor unit (200) and the mode change control device (300) may stop cooling operation based on user input corresponding to an operation mode switching command. For example, step 1230 may include steps 1233 and 1237. In step 1233, the indoor unit (200) may control the indoor EEV (220) to close in order to stop cooling operation. In step 1237, the mode change control device (300) may control the cooling valve (320) to close in order to stop cooling operation.

[0194] In step 1240, the indoor unit (200) can detect a first temperature of the indoor heat exchanger. Here, the first temperature may be a first time point refrigerant temperature obtained through a refrigerant temperature sensor that detects the temperature of the refrigerant passing through the indoor heat exchanger. The first time point refrigerant temperature may be a temperature prior to performing pressure equilibrium control.

[0195] In step 1250, the indoor unit (200) and the mode change control device (300) can perform pressure-balancing control for increasing the refrigerant pressure of the indoor unit (200). The air conditioner (1000) can increase the refrigerant pressure in the low-pressure section formed on the second side (indoor unit (200) side) of the heating valve (310) to reduce the refrigerant pressure difference between the low-pressure section and the high-pressure section formed on the first side (outdoor unit (100) side) and the second side (indoor unit (200) side) of the heating valve (310).

[0196] For example, referring to the pressure balancing step (403) of FIG. 4a, when the indoor EEV (220) is used as a pressure balancing EEV for switching from cooling operation to heating operation, the indoor unit (200) can open the indoor EEV (220) to a predetermined opening while the heating main valve (410) and the cooling main valve (420) are closed. The air conditioner (1000) can open the indoor EEV (220) to increase the refrigerant pressure in the low-pressure section formed on the second side (indoor unit (200) side) of the heating main valve (410).

[0197] For example, referring to the pressure balancing step (603) of FIG. 6a, when the heating EEV (610) is used as a pressure balancing EEV for switching from cooling operation to heating operation, the mode change control device (300b) can control the heating EEV (610) to open to a minimum opening. The air conditioner (1000) can open the heating EEV (610) to a minimum opening to increase the refrigerant pressure in the low-pressure section formed on the second side (indoor unit (200) side) of the heating EEV (610).

[0198] For example, referring to the pressure balancing step (803) of FIG. 8a, when the heating sub-valve (830) is used as a pressure balancing EEV for switching from cooling operation to heating operation, the mode change control device (300c) can control the heating sub-valve (830) to open while the heating main valve (810) and the cooling main valve (820) are closed. The air conditioner (1000) can open the heating sub-valve (830) to increase the refrigerant pressure in the low-pressure section formed on the second side (indoor unit (200) side) of the heating main valve (810).

[0199] In step 1260, the indoor unit (200) can detect a second temperature of the indoor heat exchanger. Here, the second temperature may be a second refrigerant temperature obtained through a refrigerant temperature sensor that detects the temperature of the refrigerant passing through the indoor heat exchanger. The second refrigerant temperature may be a temperature after pressure equilibrium control is performed. Here, the first refrigerant temperature and the second refrigerant temperature may be different temperatures at different times measured at the same location among the inlet, middle, or outlet of the refrigerant pipe passing through the indoor heat exchanger.

[0200] In step 1270, the indoor unit (200) can determine whether the temperature rise between the first refrigerant temperature and the second refrigerant temperature is greater than a predetermined value. Here, the predetermined value may be a reference temperature for determining whether the refrigerant pressure has changed normally according to the pressure-balancing control. For example, if the refrigerant pressure has changed normally according to the pressure-balancing control, the refrigerant temperature at the second time point may increase by about 20 degrees compared to the refrigerant temperature at the first time point. In this case, the predetermined value may be about 15 degrees. If the temperature rise between the first refrigerant temperature and the second refrigerant temperature is greater than 15 degrees, the indoor unit (200) can determine that the pressure-balancing control has been performed normally.

[0201] Here, steps 1240 to 1270 may correspond to steps 1130 and 1140 of FIG. 11.

[0202] In step 1280, the indoor unit (200) determines that pressure equilibrium control has been performed normally and can perform heating operation if the temperature rise range between the first time point refrigerant temperature and the second time point refrigerant temperature is greater than a predetermined value. For example, step 1280 may include steps 1283 and 1287. In step 1283, the indoor unit (200) may control the indoor EEV (220) to open in order to perform heating operation. The indoor unit (200) may generate a control signal for performing heating operation and transmit it to the mode change control device (300), but is not limited thereto. In step 1287, the mode change control device (300) may control the heating valve (310) to open in order to perform heating operation. For example, the mode change control device (300) may control the heating valve (310) to open based on receiving a control signal for performing heating operation. Here, step 1280 corresponds to step 1150 of FIG. 11, and step 1290 may correspond to step 1160 of FIG. 11.

[0203] In step 1290, if the temperature rise between the first time point refrigerant temperature and the second time point refrigerant temperature is less than or equal to a predetermined value, the indoor unit (200) determines that pressure-balancing control has not been performed normally and may stop operation. For example, step 1290 may include steps 1293, 1295, 1297, and 1299. In step 1293, if pressure-balancing control has not been performed normally, the indoor unit (200) may generate an error code. The indoor unit (200) may transmit the error code to the mode change control device (300) via the indoor unit communication unit (2030). In step 1295, the indoor unit (200) may control the indoor EEV (220) to close in order to stop the operation of the indoor unit (200). In step 1297, the mode change control device (300) may control the heating valve (310) and the cooling valve (320) to close in order to stop the operation of the mode change control device (300) based on an error code received from the indoor unit (200) through the central communication unit (3030). In step 1299, the indoor unit (200) may output the error code through an output interface provided in the indoor unit (200). For example, the error code may be displayed on the display of the indoor unit (200), but is not limited thereto.

[0204] For example, the air conditioner (1000) may open the heating main valve (410) of FIG. 4a, the cooling EEV (620) of FIG. 6a, or the cooling main valve (820) of FIG. 8a for heating operation only when pressure-balancing control is performed normally. Accordingly, noise, vibration, and shock can be prevented or reduced from occurring in the air conditioner (1000).

[0205] FIG. 13 is a flowchart illustrating a method for detecting a pressure-balancing control error when an air conditioner according to one embodiment of the present disclosure switches from a heating operation to a cooling operation. FIG. 13 is explained in conjunction with FIG. 10.

[0206] Referring to FIG. 13, in step 1310, the indoor unit (200) and the mode change control device (300) can perform heating operation. For example, step 1310 may include steps 1313 and 1317. In step 1313, the indoor unit (200) can be controlled to open the indoor EEV (220) for heating operation. In step 1317, the mode change control device (300) can be controlled to open the heating valve (310) for heating operation.

[0207] Here, step 1310 may correspond to at least one of the heating operation step (501) of FIG. 5a, the heating operation step (701) of FIG. 7a, or the heating operation step (901) of FIG. 9a. The heating valve (310) may correspond to at least one of the heating main valve (410) of FIG. 5a, the heating EEV (610) of FIG. 7a, or the heating main valve (810) of FIG. 9a. Meanwhile, the cooling valve (320) may correspond to at least one of the cooling main valve (420) of FIG. 4a, the cooling EEV (620) of FIG. 6a, or the cooling main valve (820) of FIG. 8a. Step 1310 may correspond to step 1110 of FIG. 11.

[0208] In step 1320, the indoor unit (200) can receive user input corresponding to an operation mode switching command. For example, if the indoor unit (200) receives a cooling operation setting input while performing a heating operation, it can generate a control signal to perform a switching operation from a heating operation to a cooling operation. In step 1325, the indoor unit (200) can transmit a control signal corresponding to the operation mode switching command to a mode change control device (300) through the indoor unit communication unit (2030). The mode change control device (300) can receive a control signal corresponding to the operation mode switching command from the indoor unit (200) through the central communication unit (3030).

[0209] In step 1330, the indoor unit (200) and the mode change control device (300) may stop the heating operation based on user input corresponding to the operation mode switching command. For example, step 1330 may include steps 1333 and 1337. In step 1333, the indoor unit (200) may control the indoor EEV (220) to close in order to stop the heating operation. In step 1337, the mode change control device (300) may control the heating valve (310) to close in order to stop the heating operation.

[0210] Here, steps 1320 to 1330 may correspond to step 1120 of FIG. 11.

[0211] In step 1340, the indoor unit (200) can detect a first temperature of the indoor heat exchanger. The first temperature may be the refrigerant temperature at a first time point.

[0212] In step 1350, the indoor unit (200) and the mode change control device (300) can perform pressure-balancing control for lowering the refrigerant pressure of the indoor unit (200). The air conditioner (1000) can lower the refrigerant pressure in the high-pressure section formed on the second side (indoor unit (200)) of the cooling valve (320) to reduce the refrigerant pressure difference between the low-pressure section and the high-pressure section formed on both sides of the cooling valve (320).

[0213] For example, referring to the pressure balancing step (503) of FIG. 5a, when the cooling sub-valve (430) is used as a pressure balancing EEV for switching from heating operation to cooling operation, the mode change control device (300) can open the cooling sub-valve (430) while the heating main valve (410) and the cooling main valve (420) are closed. The air conditioner (1000) can open the cooling sub-valve (430) to lower the refrigerant pressure in the high-pressure section formed on the second side (indoor unit (200) side) of the cooling main valve (420).

[0214] For example, referring to the pressure balancing step (703) of FIG. 7a, when the cooling EEV (620) is used as a pressure balancing EEV for switching from heating operation to cooling operation, the mode change control device (300) can control the cooling EEV (620) to open to a minimum opening. The air conditioner (1000) can open the cooling EEV (620) to a minimum opening to lower the refrigerant pressure in the high-pressure section formed on the second side (indoor unit (200) side) of the cooling EEV (620).

[0215] For example, referring to the pressure balancing step (903) of FIG. 9a, when the cooling sub-valve (840) is used as a pressure balancing EEV for switching from heating operation to cooling operation, the mode change control device (300) can control the cooling sub-valve (840) to open while the heating main valve (810) and the cooling main valve (820) are closed. The air conditioner (1000) can open the cooling sub-valve (840) to lower the refrigerant pressure in the high-pressure section formed on the second side (indoor unit (200) side) of the cooling main valve (420).

[0216] In step 1360, the indoor unit (200) can detect a second temperature of the indoor heat exchanger. The second temperature may be the refrigerant temperature at a second time point.

[0217] In step 1370, the indoor unit (200) can determine whether the temperature drop between the first refrigerant temperature and the second refrigerant temperature is greater than a predetermined value. For example, if the refrigerant pressure is changed normally according to the pressure-balancing control, the refrigerant temperature at the second time point may decrease by about 20 degrees compared to the refrigerant temperature at the first time point. In this case, the predetermined value may be about 15 degrees. If the temperature drop between the first refrigerant temperature and the second refrigerant temperature is greater than 15 degrees, the indoor unit (200) can determine that the pressure-balancing control has been performed normally.

[0218] Here, steps 1340 to 1370 may correspond to steps 1130 and 1140 of FIG. 11.

[0219] In step 1380, the indoor unit (200) determines that pressure-balancing control has been performed normally and can perform cooling operation if the temperature drop range between the first time point refrigerant temperature and the second time point refrigerant temperature is greater than a predetermined value. For example, step 1380 may include steps 1383 and 1387. In step 1383, the indoor unit (200) may control the indoor EEV (220) to open in order to perform cooling operation. The indoor unit (200) may generate a control signal for performing cooling operation and transmit it to the mode change control device (300), but is not limited thereto. In step 1387, the mode change control device (300) may control the cooling valve (320) to open in order to perform cooling operation. For example, the mode change control device (300) may control the cooling valve (320) to open based on receiving a control signal for performing cooling operation.

[0220] In step 1390, if the temperature drop between the first refrigerant temperature and the second refrigerant temperature is less than or equal to a predetermined value, the indoor unit (200) determines that pressure-balancing control has not been performed normally and may stop operation. For example, steps 1393, 1395, 1397, and 1399 may correspond to steps 1293, 1295, 1297, and 1299 of FIG. 12.

[0221] For example, the air conditioner (1000) may open the cooling main valve (420) of FIG. 5a, the cooling EEV (620) of FIG. 7a, or the cooling main valve (820) of FIG. 9a for cooling operation only when pressure-balancing control is performed normally. Accordingly, noise, vibration, and shock can be prevented or reduced from occurring in the air conditioner (1000).

[0222] Here, step 1380 corresponds to step 1150 of FIG. 11, and step 1390 may correspond to step 1160 of FIG. 11.

[0223] FIG. 14 is a diagram illustrating the operation of an air conditioner acquiring an operation mode switching command according to one embodiment of the present disclosure. FIG. 14 may correspond to the operation of the air conditioner according to step 1120 of FIG. 11.

[0224] An air conditioning system according to one embodiment of the present disclosure may include a remote controller (400-1), an indoor unit (200-1), a mode change control device (300), and an outdoor unit (100). Here, the remote controller (400-1) may be an input device connected to the indoor unit (200-1). In the air conditioning system, a plurality of remote controllers (400-1) may be provided to control each of the plurality of indoor units.

[0225] The remote controller (400-1) may include an input device capable of receiving various control commands from a user, and a device for remotely controlling at least one of the components of the air conditioner (1000) in response to the received control commands. For example, the remote controller (400-1) may include buttons, keys, pads, touch screens, etc. For example, the remote controller (400-1) may be a remote controller connected to the indoor unit (200-1) via a wired / wireless communication network. The remote controller (400-1) may also be a user terminal. For example, the user terminal may include a smartphone, or a wearable device in the form of glasses or a watch, but is not limited thereto.

[0226] The remote controller (400-1) can receive user input corresponding to a command to switch the operation mode from the first operation to the second operation. The user input corresponding to the operation mode switching command may include an operation mode setting input for selecting cooling operation or heating operation, or an indoor temperature setting input for setting the indoor temperature. For example, the remote controller (400-1) may include a heating UI (1401), a cooling UI (1402), or an indoor temperature control UI (1403). The remote controller (400-1) can receive user input corresponding to the operation mode switching command through each UI.

[0227] The remote controller (400-1) receives an operating mode setting input and can transmit the operating mode setting input to the indoor unit (200-1) (operation 1410). Alternatively, the remote controller (400-1) can transmit an indoor temperature setting input to the indoor unit (200-1) (operation 1420).

[0228] The indoor unit (200-1) can receive user input corresponding to an operation mode switching command from the remote controller (400-1) through the indoor unit communication unit (2030 in FIG. 10). Alternatively, for example, the indoor unit (200-1) can receive user input corresponding to an operation mode switching command through an input interface provided in the indoor unit (200-1).

[0229] For example, if the indoor unit (200-1) receives a heating operation setting input while performing cooling operation, it can generate a control signal to perform a switching operation from cooling operation to heating operation. For example, if the indoor unit (200-1) receives a cooling operation setting input while performing heating operation, it can generate a control signal corresponding to a switching command from heating operation to cooling operation. The indoor unit (200-1) can transmit a control signal corresponding to a switching operation mode command to a mode change control device (300) or an outdoor unit (100) (operation 1450).

[0230] Alternatively, for example, when the indoor unit (200-1) receives an indoor temperature setting input from the remote controller (400-1), it can compare the current indoor temperature with the set temperature (operation 1430) and determine whether to switch the operation mode (operation 1440). For example, when the indoor unit (200-1) is in a cooling operation state, if it receives an indoor temperature setting input (e.g., 30 degrees) that is higher than the current indoor temperature (e.g., 23 degrees), it can decide to switch from cooling operation to heating operation. For example, when the indoor unit (200-1) is in a heating operation state, if it receives an indoor temperature setting input (e.g., 18 degrees) that is lower than the current indoor temperature (e.g., 26 degrees), it can decide to switch from heating operation to cooling operation. The indoor unit (200-1) can generate a control signal corresponding to an operation mode switching command and transmit the control signal to a mode change control device (300) or an outdoor unit (100) (operation 1450).

[0231] FIG. 15 is a flowchart illustrating a method for detecting a pressure-balancing control error when switching the operating mode of an air conditioner according to one embodiment of the present disclosure.

[0232] Referring to FIG. 15, an air conditioner (1000) according to one embodiment of the present disclosure differs from FIG. 11 in that it further includes an operation in which, after pressure-balancing control, if the temperature change of the indoor heat exchanger does not reach a predetermined value, it is not immediately judged as an error, but judged as an error when the same symptom occurs n times. With the air conditioner (1000) according to one embodiment of the present disclosure, pressure-balancing control errors can be detected more accurately.

[0233] In step 1510, the air conditioner (1000) can perform a first operation. This corresponds to step 1110 of FIG. 11.

[0234] In step 1520, the air conditioner (1000) may stop the first operation based on a command to switch the operation mode from the first operation to the second operation. This corresponds to step 1120 of FIG. 11.

[0235] In step 1530, the air conditioner (1000) can perform pressure-balancing control while the first operation is stopped. This corresponds to step 1130 of FIG. 11.

[0236] In step 1540, the air conditioner (1000) can determine whether the temperature change between the first temperature and the second temperature corresponds to a predetermined value. This may be an example of a method for the air conditioner (1000) to determine whether the refrigerant pressure difference between both sides of the switching valve decreases in step 1140. The first temperature may be the refrigerant temperature at the first time point, and the second temperature may be the refrigerant temperature at the second time point.

[0237] In step 1550, the air conditioner (1000) can identify whether the same situation has occurred n times (e.g., 3 times) or more when the temperature change is below a predetermined value. Here, n can be a natural number.

[0238] In step 1560, if the air conditioner (1000) determines that a situation in which the temperature change is identified as being below a predetermined value has occurred n or more times, it can transmit an error code and stop operation.

[0239] In step 1570, the air conditioner (1000) may perform a second operation when the situation in which the temperature change is identified as being less than or equal to a predetermined value is less than n times, or when the temperature change is greater than a predetermined value.

[0240] FIG. 16 is a detailed block diagram of an air conditioner according to one embodiment of the present disclosure.

[0241] Referring to FIG. 16, an air conditioner (1600) according to one embodiment of the present disclosure may include an outdoor unit (1630), an indoor unit (1640), a mode change control device (1650), an input / output interface (1660), a communication unit (1670), a sensor (1680), a processor (1610), and a memory (1620). However, not all components shown in FIG. 16 are essential components. An air conditioner (1600) may be implemented with more components than those shown in FIG. 16, or with fewer components.

[0242] Some or all of the operations of the processor (1610) of FIG. 16 may be performed by the central processor (3010) of the mode change control device (300) of FIG. 10, by the indoor processor (2010) of the indoor unit (200), or by the outdoor processor (1010) of the outdoor unit (100).

[0243] All components of a heat pump device may be housed in a single housing that forms the exterior of the air conditioner (1600), such as a window air conditioner or a portable air conditioner. On the other hand, some components of the heat pump device may be housed separately in multiple housings that form a single air conditioner (1600), such as a wall-mounted air conditioner, a stand-type air conditioner, and a system air conditioner.

[0244] An air conditioner (1600) comprising a plurality of housings may include at least one outdoor unit (1630) installed outdoors and at least one indoor unit (1640) installed indoors. For example, the air conditioner (1600) may be configured such that one outdoor unit (1630) and one indoor unit (1640) are connected via refrigerant pipes. For example, the air conditioner (1600) may be configured such that one outdoor unit (1630) is connected via refrigerant pipes to two or more indoor units (1640). For example, the air conditioner (1600) may be configured such that two or more outdoor units (1630) and two or more indoor units (1640) are connected via a plurality of refrigerant pipes.

[0245] The outdoor unit (1630), the indoor unit (1640), and the mode change control device (1650) may be electrically connected. For example, an input interface (1662) may be provided in at least one of the outdoor unit (1630), the indoor unit (1640), and the mode change control device (1650), and a user may input information (or commands) to control the air conditioner (1600) through the input interface (1662). In response to user input, the outdoor unit (1630), the indoor unit (1640), and the mode change control device (1650) may operate simultaneously or sequentially.

[0246] The air conditioner (1600) may include an outdoor heat exchanger (1635) provided in an outdoor unit (1630) and an indoor heat exchanger (1645) provided in an indoor unit (1640). The outdoor heat exchanger (1635) may correspond to the outdoor heat exchanger (120) of FIG. 2A. The indoor heat exchanger (1645) may correspond to the indoor heat exchanger (210) of FIG. 2A. The outdoor heat exchanger (1635) or the indoor heat exchanger (1645) may each correspond to an evaporator or a condenser.

[0247] The indoor unit (1640) is installed indoors. For example, the indoor unit (1640) can be classified into a ceiling-mounted indoor unit, a stand-type indoor unit, a wall-mounted indoor unit, etc. depending on the method of placement. For example, the ceiling-mounted indoor unit can be classified into a 4-way type indoor unit, a 1-way type indoor unit, a duct-type indoor unit, etc. depending on the method of air discharge.

[0248] For example, in the case where one outdoor unit (1630) and one indoor unit (1640) are directly connected to the air conditioner (1600) through a refrigerant pipe, the refrigerant may be arranged to circulate between the one outdoor unit (1630) and the one indoor unit (1640) through the refrigerant pipe.

[0249] For example, in an air conditioner (1600), when one outdoor unit (1630) is connected to two or more indoor units (1640) through one mode change control device (1650), the refrigerant may flow to the multiple indoor units (1640) through a refrigerant pipe branching from the mode change control device (1650). The refrigerant discharged from the multiple indoor units (1640) may be combined and circulated to the outdoor unit (1630). For example, the multiple indoor units (1640) may each be directly connected in parallel to one mode change control device (1650) and the outdoor unit (1630) through separate refrigerant pipes.

[0250] Multiple indoor units (1640) can each operate independently according to an operating mode set by the user. That is, some of the multiple indoor units (1640) can be operated in a cooling mode and simultaneously some of the others can be operated in a heating mode. At this time, the refrigerant can be arranged to flow into each indoor unit (1640) in a selectively high-pressure or low-pressure state along a designated circulation path through a flow path switching valve, and to be discharged and circulated to the outdoor unit (1630).

[0251] For example, when an air conditioner (1600) has two or more outdoor units (1630) and two or more indoor units (1640) connected through multiple refrigerant pipes, the refrigerant discharged from the multiple outdoor units (1630) may be combined and flow through one refrigerant pipe, then branch off again at some point and flow into the multiple indoor units (1640).

[0252] Multiple outdoor units (1630) may all be driven or at least some may not be driven depending on the driving load according to the driving amount of multiple indoor units (1640). At this time, the refrigerant may be arranged to flow into and circulate to the outdoor unit (1630) that is selectively driven through a flow path switching valve. The air conditioner (1600) may include an expansion valve to lower the pressure of the refrigerant flowing into the heat exchanger. For example, the expansion valve may be placed inside the indoor unit (1640) or inside the outdoor unit (1630), or it may be placed in both. The expansion valve may correspond to the indoor EEV (220) of FIG. 2a.

[0253] The air conditioner (1600) may further include a flow switching valve positioned on the refrigerant circulation path. The flow switching valve may include, for example, a 4-way valve. The flow switching valve may determine the circulation path of the refrigerant depending on the operating mode of the indoor unit (1640) (e.g., cooling operation or heating operation). The flow switching valve may be connected to the discharge of the compressor.

[0254] The air conditioner (1600) may include an accumulator. The accumulator may be connected to the suction part of the compressor. Low-temperature, low-pressure refrigerant evaporated from an indoor heat exchanger (1645) or an outdoor heat exchanger (1635) may be introduced into the accumulator. When a refrigerant mixed with liquid refrigerant and refrigerant gas is introduced, the accumulator separates the liquid refrigerant from the refrigerant gas and supplies the refrigerant gas from which the liquid refrigerant has been separated to the compressor.

[0255] An outdoor fan may be provided near the outdoor heat exchanger (1635). The outdoor fan may blow outdoor air into the outdoor heat exchanger (1635) to facilitate heat exchange between the refrigerant and the outdoor air.

[0256] The indoor unit (1640) of the air conditioner (1600) may include a housing, a blower that circulates air inside or outside the housing, and an indoor heat exchanger (1645) that exchanges heat with the air flowing into the housing.

[0257] The housing may include an intake port. Indoor air can be drawn into the interior of the housing through the intake port.

[0258] The indoor unit (1640) of the air conditioner (1600) may include a filter provided to filter foreign substances in the air entering the housing through the intake port.

[0259] The housing may include an outlet. Air flowing inside the housing can be discharged to the outside of the housing through the outlet.

[0260] The housing of the indoor unit (1640) may be provided with an airflow guide that guides the direction of air discharged through the outlet. For example, the airflow guide may include a blade located over the outlet. For example, the airflow guide may include an auxiliary fan for controlling the discharge airflow. The airflow guide may be omitted and is not limited thereto.

[0261] Inside the housing of the indoor unit (1640), an indoor heat exchanger (1645) and a blower may be provided, which are positioned on a path connecting the intake port and the exhaust port.

[0262] The blower may include an indoor fan and a fan motor. For example, the indoor fan may include an axial fan, a mixed-flow fan, a cross-flow fan, or a centrifugal fan.

[0263] The indoor heat exchanger (1645) may be positioned between the blower and the outlet, or between the intake and the blower. The indoor heat exchanger (1645) may absorb heat from the air introduced through the intake or transfer heat to the air introduced through the intake. The indoor heat exchanger (1645) may include a heat exchange tube through which a refrigerant flows and a heat exchange fin in contact with the heat exchange tube to increase the heat transfer surface area.

[0264] The indoor unit (1640) of the air conditioner (1600) may include a drain tray positioned below the indoor heat exchanger (1645) to collect condensate generated in the indoor heat exchanger (1645). The condensate contained in the drain tray may be drained to the outside through a drain hose. The drain tray may be provided to support the indoor heat exchanger (1645).

[0265] The indoor unit (1640) of the air conditioner (1600) may include a power module. The power module may be connected to an external power source to supply power to the components of the indoor unit (1640).

[0266] For example, the outdoor unit (1630) can adjust the frequency of the compressor and control the flow path switching valve to switch the direction of refrigerant circulation. The outdoor unit (1630) can adjust the rotational speed of the outdoor blower fan. In addition, the outdoor unit (1630) can generate a control signal to adjust the opening of the expansion valve.

[0267] The communication unit (1670) may include one or more components that perform communication between the outdoor unit (1630), the indoor unit (1640), and the mode change control device (1650). For example, the communication unit (1670) may include a port for connecting a wired cable that performs wired communication between the outdoor unit (1630), the indoor unit (1640), and the mode change control device (1650). Additionally, for example, the communication unit (1670) may include at least one antenna for wirelessly communicating with an external device. For example, the communication unit (1670) may include at least one of a short-range communication module or a long-range communication module. A short-range wireless communication module may include, but is not limited to, a Bluetooth communication module, a BLE (Bluetooth Low Energy) communication module, a Near Field Communication module, a WLAN (Wi-Fi) communication module, a Zigbee communication module, an infrared (IrDA, infrared Data Association) communication module, a WFD (Wi-Fi Direct) communication module, an UWB (ultrawideband) communication module, an Ant+ communication module, a microwave (uWave) communication module, etc.

[0268] For example, the communication unit (1670) can communicate with external devices such as servers, mobile devices, and other home appliances through a nearby access point (AP). The access point (AP) can connect the local network (LAN) to which the air conditioner (1600) or user device is connected to the wide area network (WAN) to which the server is connected. The air conditioner (1600) or user device can be connected to the server through the wide area network (WAN).

[0269] For example, the communication unit (1670) provided in the outdoor unit (1630) may correspond to the outdoor unit communication unit (1030) of FIG. 10. The communication unit (1670) provided in the indoor unit (1640) may correspond to the indoor unit communication unit (2030). The communication unit (1670) provided in the mode change control device (1650) may correspond to the central communication unit (3030) of FIG. 10.

[0270] The sensor (1680) may be an environment sensor placed in a space inside or outside the housing. Each of the outdoor unit (1630), indoor unit (1640), and mode change control device (1650) may include at least one sensor placed at any location inside or outside. The sensor (1680) may include a temperature sensor (1682), a humidity sensor for detecting ambient air humidity, a refrigerant temperature sensor (1684) for detecting the refrigerant temperature of the refrigerant pipe, or a refrigerant pressure sensor (1686) for detecting the refrigerant pressure of the refrigerant pipe.

[0271] The memory (1620) can store / record various information required for the operation of the air conditioner (1600). The memory (1620) can store instructions, applications, data, and / or programs required for the operation of the air conditioner (1600). For example, the memory (1620) can store various programs for the cooling operation, heating operation, dehumidification operation, and / or defrosting operation of the air conditioner (1600). The memory (1620) may include volatile memory such as S-RAM (Static Random Access Memory) and D-RAM (Dynamic Random Access Memory) for temporarily storing data. Additionally, the memory (1620) may include non-volatile memory such as ROM (Read Only Memory), EPROM (Erasable Programmable Read Only Memory), and EEPROM (Electrically Erasable Programmable Read Only Memory) for long-term data storage. Programs stored in memory (1620) can be classified into multiple modules according to their functions.

[0272] The processor (1610) can generate a control signal to control the operation of the air conditioner (1600) based on instructions, applications, data, and / or programs stored in the memory (1620). The processor (1610) may be hardware and may include logic circuits and arithmetic circuits. The processor (1610) may process data according to programs and / or instructions provided from the memory (1620) and generate a control signal according to the processing result. The memory (1620) and the processor (1610) may be implemented as a single control circuit or as multiple circuits. The processor (1610) may include at least one processor.

[0273] At least one processor may be a circuitry such as a System on Chip (SoC) or an Integrated Circuit (IC). At least one processor included in the processor (1610) may be a general-purpose processor such as a CPU (Central Processing Unit), MPU (Micro Processor Unit), AP (Application Processor), DSP (Digital Signal Processor), a graphics-dedicated processor such as a GPU (Graphic Processing Unit) or VPU (Vision Processing Unit), an artificial intelligence-dedicated processor such as a NPU (Neural Processing Unit), or a communication-dedicated processor such as a CP (Communication Processor).

[0274] Each of the outdoor unit (1630), indoor unit (1640), and mode change control device (1650) may include a processor (1610) and a memory (1620). For example, the processor (1610) and memory (1620) provided in the outdoor unit (1630) may correspond to the outdoor unit processor (1010) and outdoor unit memory (1020) of FIG. 10. The processor (1610) and memory (1620) provided in the indoor unit (1640) may correspond to the indoor unit processor (2010) and indoor unit memory (2020) of FIG. 10. The processor (1610) and memory (1620) provided in the mode change control device (1650) may correspond to the central processor (3010) and central memory (3020) of FIG. 10.

[0275] The indoor unit (1640) of the air conditioner (1600) may include an input interface (1662). The input interface (1662) may include any type of user input means, including buttons, switches, touch screens and / or touch pads. The user may directly input setting data (e.g., desired indoor temperature, setting of operating mode for cooling / heating / dehumidification / air purification, setting of discharge outlet selection, and / or setting of airflow) through the input interface (1662).

[0276] The input interface (1662) may be connected to an external input device. For example, the input interface (1662) may be electrically connected to a wired remote controller. The wired remote controller may be installed at a specific location in the indoor space (e.g., a part of a wall). The user may input setting data regarding the operation of the air conditioner (1600) by operating the wired remote controller. An electrical signal corresponding to the setting data obtained through the wired remote controller may be transmitted to the input interface (1662). Additionally, the input interface (1662) may include an infrared sensor. The user may input setting data regarding the operation of the air conditioner (1600) remotely using a wireless remote controller. The setting data input through the wireless remote controller may be transmitted to the input interface (1662) as an infrared signal.

[0277] Additionally, the input interface (1662) may include a microphone. A user's voice command may be acquired through the microphone. The microphone may convert the user's voice command into an electrical signal and transmit the converted electrical signal to the indoor unit processor. The indoor unit processor may control the components of the air conditioner (1600) to execute a function corresponding to the user's voice command. Setting data acquired through the input interface (1662) (e.g., desired indoor temperature, setting of operating mode for cooling / heating / dehumidification / air purification, setting of discharge outlet selection, and / or setting of airflow) may be transmitted to the indoor unit processor described later. In one example, the setting data acquired through the input interface (1662) may be transmitted externally, i.e., to an outdoor unit (1630), a mode change control device (1650), or a server, via the indoor unit communication unit.

[0278] In one example, an output interface (1664) may be provided in an indoor unit (1640). The output interface (1664) is electrically connected to an indoor unit processor and can output information related to the operation of the air conditioner (1600) under the control of the indoor unit processor. For example, information such as an operating mode selected by user input, wind direction, air volume, and temperature may be output. Additionally, the output interface (1664) may output sensing information obtained from an indoor unit sensor or an outdoor unit sensor, and warning / error messages.

[0279] The output interface (1664) may include a display and a speaker. The speaker may output various sounds as an acoustic device. The display may display information entered by the user or information provided to the user as various graphic elements. For example, operation information of the air conditioner (1600) may be displayed as at least one of an image or text. Additionally, the display may include an indicator that provides specific information.

[0280] In one embodiment of the present disclosure, a control method for an air conditioner comprises: a step of performing a first operation corresponding to either a cooling operation or a heating operation; a step of stopping the first operation based on a command to switch from the first operation to a second operation corresponding to the other of the cooling operation or the heating operation; a step of performing pressure-balancing control such that, while the first operation is stopped, the refrigerant pressure difference between both sides of a switching valve for the second operation is reduced; a step of determining whether the refrigerant pressure difference is reduced based on the pressure-balancing control; and a step of determining whether to perform the second operation based on the result of the determination.

[0281] In one embodiment of the present disclosure, the mode change control device includes a cooling valve and a heating valve, and the step of performing the pressure-balancing control when the first operation is stopped includes: a step of adjusting the refrigerant pressure in the low-pressure section to increase so that the pressure difference between the high-pressure section corresponding to the first side of the heating valve and the low-pressure section corresponding to the second side of the heating valve is reduced when the first operation is the cooling operation and the cooling operation is stopped; and a step of adjusting the refrigerant pressure in the high-pressure section to decrease so that the pressure difference between the low-pressure section corresponding to the first side of the cooling valve and the high-pressure section corresponding to the second side of the cooling valve is reduced when the first operation is the heating operation and the heating operation is stopped, wherein the first side corresponds to the outdoor unit side and the second side corresponds to the indoor unit side.

[0282] In one embodiment of the present disclosure, the mode change control device comprises a heating main valve corresponding to the heating valve, a cooling main valve corresponding to the cooling valve, and a cooling sub-valve, and when the cooling operation is stopped, the step of controlling to increase the refrigerant pressure in the low-pressure section includes the step of controlling to open the opening of an indoor EEV (Electronic Expansion Valve) included in the indoor unit to increase the refrigerant pressure in the low-pressure section corresponding to the second side of the heating main valve, and when the heating operation is stopped, the step of controlling to decrease the refrigerant pressure in the high-pressure section may include the step of controlling to open the opening of a cooling sub-valve included in the mode change control device to decrease the refrigerant pressure in the high-pressure section corresponding to the second side of the cooling main valve.

[0283] In one embodiment of the present disclosure, the mode change control device includes a heating EEV corresponding to the heating valve and a cooling EEV corresponding to the cooling valve, and when the cooling operation is stopped, the step of controlling to increase the refrigerant pressure in the low-pressure section includes the step of controlling the heating EEV to open to a minimum opening to increase the refrigerant pressure in the low-pressure section corresponding to the second side of the heating EEV, and when the heating operation is stopped, the step of controlling to decrease the refrigerant pressure in the high-pressure section may include the step of controlling the cooling EEV to open to a minimum opening to decrease the refrigerant pressure in the high-pressure section corresponding to the second side of the cooling EEV.

[0284] In one embodiment of the present disclosure, the mode change control device comprises a heating main valve corresponding to the heating valve, a cooling main valve corresponding to the cooling valve, a heating sub valve, and a cooling sub valve, and when the cooling operation is stopped, the step of controlling to increase the refrigerant pressure in the low-pressure section includes the step of controlling to open the heating sub valve to increase the refrigerant pressure in the low-pressure section corresponding to the second side of the heating main valve, and when the heating operation is stopped, the step of controlling to decrease the refrigerant pressure in the high-pressure section may include the step of controlling to open the cooling sub valve to decrease the refrigerant pressure in the high-pressure section corresponding to the second side of the cooling main valve.

[0285] In one embodiment of the present disclosure, the indoor unit includes an indoor heat exchanger and a refrigerant temperature sensor that senses the temperature of a refrigerant pipe passing through the indoor heat exchanger, and the step of determining whether the refrigerant pressure difference is reduced includes the step of obtaining a refrigerant temperature at a first time point before the pressure equilibrium control is performed through the refrigerant temperature sensor, the step of obtaining a refrigerant temperature at a second time point after the pressure equilibrium control is performed through the refrigerant temperature sensor, and the step of determining whether the temperature difference between the refrigerant temperature at the first time point and the refrigerant temperature at the second time point corresponds to a predetermined condition, and the step of determining whether to perform the second operation based on the determination result may include the step of performing the second operation when it is determined that the temperature difference corresponds to the predetermined condition, and the step of stopping the first operation and the second operation when it is determined that the temperature difference does not correspond to the predetermined condition.

[0286] In one embodiment of the present disclosure, the step of determining whether to perform the second operation based on the result of the determination may include the step of performing the second operation when it is determined that the refrigerant pressure difference has decreased, and the step of stopping the first operation and the second operation and transmitting an error code from the indoor unit to a mode change control device when it is determined that the refrigerant pressure difference has not decreased.

[0287] In one embodiment of the present disclosure, the step of determining whether to perform the second operation based on the result of the determination may further include the step of displaying the error code on the display of the indoor unit as it is determined that the refrigerant pressure difference has not decreased.

[0288] In one embodiment of the present disclosure, the method may further include the steps of: receiving an operation mode setting input for selecting the cooling operation or the heating operation or an indoor temperature setting input for setting the indoor temperature from a user through an input interface provided in the air conditioner; and transmitting a control signal corresponding to a switching command from the indoor unit to the mode change control device based on the setting input received from the user.

[0289] In one embodiment of the present disclosure, the air conditioner comprises an outdoor unit, a plurality of indoor units connected to the outdoor unit, a mode change control device connecting the outdoor unit and the plurality of indoor units for switching between cooling operation and heating operation of each indoor unit, a memory including one or more storage media for storing one or more instructions, and at least one processor including a processing circuit.

[0290] By executing one or more instructions individually or in combination by the at least one processor according to one embodiment of the present disclosure, the air conditioner performs a first operation corresponding to either a cooling operation or a heating operation. By executing one or more instructions individually or in combination by the at least one processor according to one embodiment of the present disclosure, the air conditioner stops the first operation based on a switching command to a second operation corresponding to the other of the cooling operation or the heating operation during the first operation. The air conditioner according to one embodiment of the present disclosure performs pressure-balancing control so that the refrigerant pressure difference between both sides of a switching valve for the second operation is reduced while the first operation is stopped. The air conditioner according to one embodiment of the present disclosure determines whether the refrigerant pressure difference is reduced based on the pressure-balancing control. The air conditioner according to one embodiment of the present disclosure determines whether to perform the second operation based on the result of the determination.

[0291] In one embodiment of the present disclosure, the mode change control device includes a cooling valve and a heating valve, and by executing one or more instructions individually or in combination by the at least one processor, the air conditioner can adjust the refrigerant pressure in the low-pressure section to increase so that the pressure difference between the high-pressure section corresponding to the first side of the heating valve and the low-pressure section corresponding to the second side of the heating valve is reduced when the first operation is the cooling operation and the cooling operation is stopped. In one embodiment of the present disclosure, the air conditioner can adjust the refrigerant pressure in the high-pressure section to decrease so that the pressure difference between the low-pressure section corresponding to the first side of the cooling valve and the high-pressure section corresponding to the second side of the cooling valve is reduced when the first operation is the heating operation and the heating operation is stopped. The first side may correspond to the outdoor unit side, and the second side may correspond to the indoor unit side.

[0292] In one embodiment of the present disclosure, the mode change control device includes a heating main valve corresponding to the heating valve, a cooling main valve corresponding to the cooling valve, and a cooling sub-valve, and by executing one or more instructions individually or in combination by the at least one processor, the air conditioner can control the opening of an indoor EEV (Electronic Expansion Valve) included in the indoor unit to increase the refrigerant pressure in the low-pressure section corresponding to the second side of the heating main valve. In one embodiment of the present disclosure, the air conditioner can control the opening of a cooling sub-valve included in the mode change control device to decrease the refrigerant pressure in the high-pressure section corresponding to the second side of the cooling main valve.

[0293] In one embodiment of the present disclosure, the mode change control device includes a heating EEV corresponding to the heating valve and a cooling EEV corresponding to the cooling valve, and by executing one or more instructions individually or in combination by the at least one processor, the air conditioner can control the heating EEV to open to a minimum opening to increase the refrigerant pressure in a low-pressure section corresponding to the second side of the heating EEV. In one embodiment of the present disclosure, the air conditioner can control the cooling EEV to open to a minimum opening to lower the refrigerant pressure in a high-pressure section corresponding to the second side of the cooling EEV.

[0294] In one embodiment of the present disclosure, the mode change control device comprises a heating main valve corresponding to the heating valve, a cooling main valve corresponding to the cooling valve, a heating sub valve, and a cooling sub valve, and by executing one or more instructions individually or in combination by the at least one processor, the air conditioner can be controlled to open the heating sub valve to increase the refrigerant pressure in a low-pressure section corresponding to the second side of the heating main valve. In one embodiment of the present disclosure, the air conditioner can be controlled to open the cooling sub valve to lower the refrigerant pressure in a high-pressure section corresponding to the second side of the cooling main valve.

[0295] In one embodiment of the present disclosure, the indoor unit includes an indoor heat exchanger and a refrigerant temperature sensor that senses the temperature of a refrigerant pipe passing through the indoor heat exchanger, and by executing one or more instructions individually or in combination by the at least one processor, the air conditioner can obtain a refrigerant temperature at a first time point before the pressure equilibrium control is performed through the refrigerant temperature sensor, obtain a refrigerant temperature at a second time point after the pressure equilibrium control is performed through the refrigerant temperature sensor, and determine whether the temperature difference between the refrigerant temperature at the first time point and the refrigerant temperature at the second time point corresponds to a predetermined condition. In one embodiment of the present disclosure, the air conditioner can perform the second operation when it is determined that the temperature difference corresponds to the predetermined condition, and stop the first operation and the second operation when it is determined that the temperature difference does not correspond to the predetermined condition.

[0296] In one embodiment of the present disclosure, by executing one or more instructions individually or in combination by the at least one processor, the air conditioner performs the second operation when it is determined that the refrigerant pressure difference has decreased, stops the first operation and the second operation when it is determined that the refrigerant pressure difference has not decreased, and transmits an error code from the indoor unit to a mode change control device.

[0297] In one embodiment of the present disclosure, by executing one or more instructions individually or in combination by the at least one processor, the air conditioner receives an operation mode setting input for selecting the cooling operation or the heating operation or an indoor temperature setting input for setting the indoor temperature from a user through an input interface provided in the air conditioner, and based on the setting input received from the user, transmits a control signal corresponding to an operation mode switching command from the indoor unit to the mode change control device.

[0298] In one embodiment of the present disclosure, an indoor unit may be provided. The indoor unit may include an indoor unit connected to an outdoor unit and a mode change control device, an indoor heat exchanger, an indoor EEV, an indoor unit communication unit, a memory including one or more storage media for storing one or more commands, and a processing circuit.

[0299] In one embodiment of the present disclosure, the indoor unit may perform a first operation corresponding to either a cooling operation or a heating operation by opening the indoor EEV. In one embodiment of the present disclosure, the indoor unit may obtain a command to switch to a second operation corresponding to the other of the cooling operation or the heating operation during the first operation. In one embodiment of the present disclosure, the indoor unit may stop the first operation by controlling the indoor EEV to close based on the switching command. In one embodiment of the present disclosure, the indoor unit transmits a control signal corresponding to the switching command to the outdoor unit and the mode change control device through the indoor unit communication unit. In one embodiment of the present disclosure, the indoor unit determines whether the refrigerant pressure difference between both sides of the switching valve for the second operation decreases while the first operation is stopped. In one embodiment of the present disclosure, the indoor unit determines whether to perform the second operation by opening the indoor EEV based on the result of the determination.

[0300] In one embodiment of the present disclosure, the indoor unit further includes a refrigerant temperature sensor that senses the temperature of a refrigerant pipe passing through the indoor heat exchanger, and by executing the one or more instructions individually or in combination by the at least one processor, the indoor unit obtains a first refrigerant temperature before pressure-balancing control is performed through the refrigerant temperature sensor, obtains a second refrigerant temperature after pressure-balancing control is performed through the refrigerant temperature sensor, determines whether the temperature difference between the first refrigerant temperature and the second refrigerant temperature corresponds to a predetermined condition, and when it is determined that the temperature difference corresponds to the predetermined condition, controls the indoor EEV to open, transmits an error code to the mode change control device through the indoor unit communication unit, and when it is determined that the temperature difference does not correspond to the predetermined condition, controls the indoor EEV to close.

[0301] A device-readable storage medium may be provided in the form of a non-transitory storage medium. Here, 'non-transitory storage medium' simply means that it is a tangible device and does not contain a signal (e.g., electromagnetic waves), and the term does not distinguish between cases where data is stored semi-permanently and cases where it is stored temporarily. For example, a 'non-transitory storage medium' may include a buffer in which data is stored temporarily.

[0302] According to one embodiment, the method according to the various embodiments disclosed herein may be provided by being included in a computer program product. The computer program product may be traded between a seller and a buyer as a product. The computer program product may be distributed in the form of a device-readable storage medium (e.g., compact disc read-only memory (CD-ROM)), or distributed online (e.g., download or upload) through an application store or directly between two user devices (e.g., smartphones). In the case of online distribution, at least a portion of the computer program product (e.g., downloadable app) may be temporarily stored or temporarily created on a device-readable storage medium, such as the memory of a manufacturer's server, an application store's server, or a relay server.

Claims

1. A control method for an air conditioner (1000), comprising an outdoor unit (100), a plurality of indoor units connected to the outdoor unit (100), and a mode change control device (300) connecting the outdoor unit (100) and the plurality of indoor units, and including at least one valve for switching between cooling operation and heating operation of each indoor unit (200). A step of performing a first operation corresponding to either a cooling operation or a heating operation; In the first operation, a step of stopping the first operation based on a command to switch to a second operation corresponding to the other of the cooling operation or the heating operation; A step of performing pressure-balancing control such that, while the first operation is stopped, the refrigerant pressure difference between both sides of the switching valve for the second operation is reduced; A step of determining whether the refrigerant pressure difference based on the above pressure equilibrium control is reduced; and A method comprising the step of determining whether to perform the second operation based on the above judgment result.

2. In Paragraph 1, The above mode change control device (300) includes a cooling valve (320) and a heating valve (310), and The step of performing the pressure-balancing control while the first operation is stopped is: When the first operation is the cooling operation, in a state where the cooling operation is stopped, a step of adjusting to increase the refrigerant pressure in the low-pressure section so that the pressure difference between the high-pressure section corresponding to the first side of the heating valve (310) and the low-pressure section corresponding to the second side of the heating valve (310) is reduced; and When the first operation is the heating operation, the method includes the step of lowering the refrigerant pressure in the high-pressure section so that the pressure difference between the low-pressure section corresponding to the first side of the cooling valve (320) and the high-pressure section corresponding to the second side of the cooling valve (320) is reduced while the heating operation is stopped. A method in which the first side corresponds to the outdoor unit (100) side and the second side corresponds to the indoor unit (200) side.

3. In Paragraph 2, The above mode change control device (300a) includes a heating main valve (410) corresponding to the heating valve (310), a cooling main valve (420) corresponding to the cooling valve (320), and a cooling sub valve (430). The step of adjusting the refrigerant pressure in the low-pressure section to increase it while the above cooling operation is stopped is, To increase the refrigerant pressure in the low-pressure section corresponding to the second side of the heating main valve (410), the method includes the step of controlling the opening of the indoor EEV (Electronic Expansion Valve) (220) included in the indoor unit (200) to open. The step of adjusting the refrigerant pressure in the high-pressure section to lower it while the heating operation is stopped is: A method comprising the step of controlling the opening of a cooling sub-valve (430) included in the mode change control device (300a) to open the refrigerant pressure in the high-pressure section corresponding to the second side of the cooling main valve (420) to lower the refrigerant pressure.

4. In Paragraph 2, The above mode change control device (300b) includes a heating EEV (610) corresponding to the heating valve (310) and a cooling EEV (620) corresponding to the cooling valve (320). The step of adjusting the refrigerant pressure in the low-pressure section to increase it while the above cooling operation is stopped is, To increase the refrigerant pressure in the low-pressure section corresponding to the second side of the heating EEV (610), the method includes the step of controlling the heating EEV (610) to open to a minimum opening. The step of adjusting the refrigerant pressure in the high-pressure section to lower it while the heating operation is stopped is: A method comprising the step of controlling the cooling EEV (620) to open to a minimum opening to lower the refrigerant pressure in the high-pressure section corresponding to the second side of the cooling EEV (620).

5. In Paragraph 2, The above mode change control device (300c) further includes a heating main valve (810) corresponding to the heating valve (310), a cooling main valve (820) corresponding to the cooling valve (320), a heating sub valve (830), and a cooling sub valve (840). The step of adjusting the refrigerant pressure in the low-pressure section to increase it while the above cooling operation is stopped is, The method includes the step of controlling the heating sub-valve (830) to open in order to increase the refrigerant pressure in the low-pressure section corresponding to the second side of the heating main valve (810). The step of adjusting the refrigerant pressure in the high-pressure section to lower it while the heating operation is stopped is: A method comprising the step of controlling the cooling sub-valve (840) to open in order to lower the refrigerant pressure in the high-pressure section corresponding to the second side of the cooling main valve (820).

6. In any one of paragraphs 1 through 5, The indoor unit (200) includes an indoor heat exchanger (210) and a refrigerant temperature sensor (241, 242) that senses the temperature of a refrigerant pipe passing through the indoor heat exchanger (210). The step of determining whether the above refrigerant pressure difference is reduced is: A step of obtaining a first refrigerant temperature before the pressure equilibrium control is performed through the refrigerant temperature sensors (241, 242); A step of obtaining a second refrigerant temperature after the pressure equilibrium control is performed through the refrigerant temperature sensors (241, 242); and It includes a step of determining whether the temperature difference between the first time point refrigerant temperature and the second time point refrigerant temperature corresponds to a predetermined condition, Based on the above judgment result, the step of determining whether to perform the second operation is, A step of performing the second operation as it is determined that the above temperature difference corresponds to the above-determined condition; and A method comprising the step of stopping the first operation and the second operation as it is determined that the above temperature difference does not correspond to the above-determined condition.

7. In any one of paragraphs 1 through 6, Based on the above judgment result, the step of determining whether to perform the second operation is, A step of performing the second operation as it is determined that the above refrigerant pressure difference has decreased; and A method comprising the step of stopping the first operation and the second operation and transmitting an error code from the indoor unit (200) to the mode change control device (300) as it is determined that the above refrigerant pressure difference has not decreased.

8. In Paragraph 7, Based on the above judgment result, the step of determining whether to perform the second operation is, A method further comprising the step of displaying the error code on the display of the indoor unit (200) as it is determined that the above refrigerant pressure difference has not decreased.

9. In any one of paragraphs 1 through 8, The above method is, A step of receiving, through an input interface provided in the air conditioner (100), an operation mode setting input for selecting the cooling operation or the heating operation or an indoor temperature setting input for setting the indoor temperature from a user; and A method further comprising the step of transmitting a control signal corresponding to a switching command from an indoor unit to a mode change control device based on the received setting input.

10. In an air conditioner (1000), Outdoor unit (100); A plurality of indoor units connected to the above outdoor unit (100); A mode change control device (300) that connects the above outdoor unit (100) and the above plurality of indoor units and includes at least one valve for switching between cooling operation and heating operation of each indoor unit (200); Memory (1620) comprising one or more storage media for storing one or more instructions; and It includes at least one processor (1610) including a processing circuit, and By executing the one or more instructions individually or collectively by the at least one processor (1610), the air conditioner (1000) is, Performing a first operation corresponding to either cooling operation or heating operation, In the above first operation, the first operation is stopped based on a command to switch to a second operation corresponding to the other of the cooling operation or the heating operation, and With the first operation stopped, pressure-balancing control is performed so that the refrigerant pressure difference between both sides of the switching valve for the second operation is reduced. Determining whether the refrigerant pressure difference based on the above pressure equilibrium control is reduced, and An air conditioner that determines whether to perform the second operation based on the above judgment result.

11. In Paragraph 10, The above mode change control device (300) includes a cooling valve (320) and a heating valve (310), and By executing the one or more instructions individually or in combination by the at least one processor (1610), the air conditioner (1000) is, When the first operation is the cooling operation, the refrigerant pressure in the low-pressure section is increased so that the pressure difference between the high-pressure section corresponding to the first side of the heating valve (310) and the low-pressure section corresponding to the second side of the heating valve (310) is reduced when the cooling operation is stopped. When the first operation is the heating operation, the refrigerant pressure in the high-pressure section is lowered so that the pressure difference between the low-pressure section corresponding to the first side of the cooling valve (320) and the high-pressure section corresponding to the second side of the cooling valve (320) is reduced while the heating operation is stopped. An air conditioner, wherein the first side corresponds to the outdoor unit (100) side and the second side corresponds to the indoor unit (200) side.

12. In Paragraph 11, The above mode change control device (300a) includes a heating main valve (410) corresponding to the heating valve (310), a cooling main valve (420) corresponding to the cooling valve (320), and a cooling sub valve (430). By executing the one or more instructions individually or in combination by the at least one processor (1610), the air conditioner (1000) is, In order to increase the refrigerant pressure in the low-pressure section corresponding to the second side of the heating main valve (410), the opening of the indoor EEV (Electronic Expansion Valve) (220) included in the indoor unit (200) is controlled to open, and An air conditioner that controls the opening of a cooling sub-valve (430) included in the mode change control device (300a) to lower the refrigerant pressure in the high-pressure section corresponding to the second side of the cooling main valve (420).

13. In Paragraph 11, The above mode change control device (300b) includes a heating EEV (610) corresponding to the heating valve (310) and a cooling EEV (620) corresponding to the cooling valve (320). By executing the one or more instructions individually or in combination by the at least one processor (1610), the air conditioner (1000) is, In order to increase the refrigerant pressure in the low-pressure section corresponding to the second side of the heating EEV (610), the heating EEV (610) is controlled to open to a minimum opening, and An air conditioner that controls the cooling EEV (620) to open to a minimum opening to lower the refrigerant pressure in the high-pressure section corresponding to the second side of the cooling EEV (620).

14. In Paragraph 11, The above mode change control device (300c) further includes a heating main valve (810) corresponding to the heating valve (310), a cooling main valve (820) corresponding to the cooling valve (320), a heating sub valve (830), and a cooling sub valve (840). By executing the one or more instructions individually or in combination by the at least one processor (1610), the air conditioner (1000) is, To increase the refrigerant pressure in the low-pressure section corresponding to the second side of the heating main valve (810), the heating sub valve (830) is controlled to open, and An air conditioner that controls the cooling sub-valve (840) to open in order to lower the refrigerant pressure in the high-pressure section corresponding to the second side of the cooling main valve (820).

15. A computer-readable recording medium having a program recorded thereon for performing the method of any one of paragraphs 1 through 9 on a computer.

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