Air conditioner

Abstract

An air conditioner including a compressor that compresses refrigerant; an indoor heat exchanger that exchanges heat between the refrigerant and indoor air; a heat exchanger temperature sensor that detects a temperature of the indoor heat exchanger; an indoor temperature sensor that detects an indoor temperature; and a controller. The controller may first control the compressor based on a first target temperature for the indoor heat exchanger, the first target temperature corresponding to the indoor temperature; second control, if the first control ends, the compressor based on a below-zero second target temperature lower than the first target temperature for the indoor heat exchanger; set, if the second control ends, a driving frequency of the compressor to a preset minimum frequency during a period of time; and if the period of time has elapsed, determine whether to repeat the first control based on a condition related to the second control.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to an air conditioner, and more particularly, to an air conditioner capable of removing foreign matter adsorbed on an indoor heat exchanger.BACKGROUND ART

[0002] An air conditioner is installed to provide a more comfortable indoor environment for humans by discharging cooled or heated air into a room to adjust an indoor temperature and purify air so as to create a pleasant indoor environment. Such an air conditioner typically includes an indoor unit including a heat exchanger and installed indoors, and an outdoor unit including a compressor and a heat exchanger to supply refrigerant to the indoor unit.

[0003] The air conditioner operates in a cooling mode or a heating mode depending on the flow of refrigerant. During the cooling operation, high-temperature and high-pressure liquid refrigerant is supplied to the indoor unit from the compressor of the outdoor unit by passing through the heat exchanger of the outdoor unit. As the refrigerant is expanded and vaporized in the heat exchanger of the indoor unit, ambient temperature decreases, and as an indoor unit fan is rotated, cooled air is discharged into the indoor space. During the heating operation, high-temperature and high-pressure gaseous refrigerant is supplied to the indoor unit from the compressor of the outdoor unit, and air is heated by energy, which is released as the high-temperature and high-pressure gaseous refrigerant is liquefied in the heat exchanger of the indoor unit, and the heated air is discharged to the indoor space by the rotation of the indoor unit fan.

[0004] Meanwhile, while the air conditioner is operating, foreign substances such as dust may be adsorbed on the heat exchanger of the indoor unit. For example, while the air conditioner performs a cooling operation, condensed water may be generated by heat exchange between a refrigerant and indoor air in the heat exchanger of the indoor unit. In this case, when some of the condensed water is formed on the surface of the heat exchanger or remains in a drain pipe through which the condensed water is discharged, foreign substances and the like may be adsorbed on the condensed water.

[0005] As such, when foreign substances are adsorbed on the heat exchanger of the indoor unit or the like, microorganisms such as bacteria and fungi may grow due to the foreign substances, which not only can cause discomfort to a user, but can also adversely affect a user's health. In view of this, numerous research has been conducted for the removal of foreign substances.

[0006] In order to remove foreign substances adsorbed on the heat exchanger of the indoor unit, as disclosed in Related Art 1 (Japanese Laid-Open Patent Publication No. 2010-014288), which is hereby incorporated by reference, a conventional air conditioner forms frost on the surface of the heat exchanger of the indoor unit by using a refrigerant cycle, and then performs a defrosting operation to remove the frost formed on the surface of the heat exchanger. In this case, as the water formed on the surface of the heat exchanger flows and is drained by the defrosting operation, foreign substances adsorbed on the heat exchanger of the indoor unit may be removed together with the water.

[0007] In addition, as disclosed in Related Art 2 (Japanese Laid-Open Patent Publication No. 2018-200128), which is hereby incorporated by reference, a conventional air conditioner operates so that water droplets are condensed on the surface of the heat exchanger of the indoor unit before frost is formed on the surface of the heat exchanger, allowing a larger amount of water to be drained when removing foreign substances.DISCLOSURETechnical Problem

[0008] It is an object of the present disclosure to solve the above and other problems.

[0009] It is another object of the present disclosure to provide an air conditioner that can effectively remove foreign matter adsorbed on an indoor heat exchanger only by temperature sensing.

[0010] It is another object of the present disclosure to provide an air conditioner that can prevent damage to a compressor that may occur while removing foreign matter adsorbed on an indoor heat exchanger.

[0011] It is another object of the present disclosure to repeat an operation of removal of foreign matter adsorbed on an indoor heat exchanger according to whether the foreign matter adsorbed on the indoor heat exchanger is sufficiently removed, thereby removing foreign matter adsorbed on the indoor heat exchanger in a more effective manner.Technical Solution

[0012] In accordance with an aspect of the present disclosure, the above and other objects can be accomplished by providing an air conditioner including: a compressor configured to compress and discharge a refrigerant; an indoor heat exchanger configured to exchange heat between the refrigerant and indoor air; a heat exchanger temperature sensor configured to detect a temperature of the indoor heat exchanger; an indoor temperature sensor configured to detect an indoor temperature; and a controller, wherein the controller is configured to: perform a primary control of the compressor based on a first target temperature for the temperature of the indoor heat exchanger, the first target temperature corresponding to the indoor temperature; when the primary control is terminated, perform a secondary control of the compressor based on a second target temperature below zero for the temperature of the indoor heat exchanger, the second target temperature being less than the first target temperature; when the secondary control is terminated, set an operating frequency of the compressor to a preset minimum frequency for a predetermined time; and when the predetermined time has elapsed, determine whether to repeat the primary control based on a condition for the secondary control.Advantageous Effects

[0013] An air conditioner according to the present disclosure has the following effects.

[0014] According to at least one of the embodiments of the present disclosure, it is possible to effectively remove foreign matter adsorbed on an indoor heat exchanger only by temperature sensing.

[0015] According to at least one of the embodiments of the present disclosure, it is possible to prevent damage to a compressor that may occur while removing foreign matter adsorbed on an indoor heat exchanger.

[0016] According to at least one of the embodiments of the present disclosure, as an operation of removal foreign matter adsorbed on an indoor heat exchanger is repeated according to whether the foreign matter adsorbed on the indoor heat exchanger is sufficiently removed suitable for the purpose, it is possible to remove foreign matter adsorbed on the indoor heat exchanger in a more effective manner.

[0017] Further scope of applicability of the present disclosure will become apparent from the following detailed description. However, it should be understood that the detailed description and specific embodiments such as preferred embodiments of the present disclosure are given by way of example only, since various changes and modifications within the idea and scope of the present disclosure may be clearly understood by those skilled in the art.BRIEF DESCRIPTION OF DRAWINGS

[0018] FIG. 1 is a diagram illustrating an exemplary configuration of an air conditioner according to an embodiment of the present disclose.

[0019] FIG. 2 is a schematic diagram of an outdoor unit and an indoor unit, according to an embodiment of the present disclosure.

[0020] FIG. 3 is a block diagram illustrating an air conditioner according to an embodiment of the present disclosure.

[0021] FIGS. 4 to 6 are flowcharts illustrating a method of operating an air conditioner, according to various embodiments of the present disclosure.

[0022] FIGS. 7 to 9 are diagrams for explaining the operation of an air conditioner, according to various embodiments of the present disclosure.MODE FOR THE INVENTION

[0023] Description will now be given in detail according to exemplary embodiments disclosed herein, with reference to the accompanying drawings. For the sake of brief description with reference to the drawings, the same or equivalent components may be denoted by the same reference numbers, and description thereof will not be repeated.

[0024] In the following description, a suffix such as “module” and “unit” may be used to refer to elements or components. Use of such a suffix herein is merely intended to facilitate description of the specification, and the suffix itself is not intended to give any special meaning or function.

[0025] In the present disclosure, terms such as “comprises or includes” or “has” are used herein and should be understood that they are intended to indicate an existence of features, numbers, steps, operations, elements, components, or combinations thereof, but do not preclude the presence or addition of one or more other features, numbers, steps, operations, elements, components, or combinations thereof.

[0026] Although the terms “first”, “second”, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another.

[0027] FIG. 1 is a diagram illustrating an exemplary configuration of an air conditioner according to an embodiment of the present disclosure.

[0028] Referring to FIG. 1, an air conditioner 100 according to an embodiment of the present disclosure may include an outdoor unit 21, and an indoor unit 31 connected to the outdoor unit 21. In the drawing, the indoor unit 31 is illustrated as a wall-mounted type air conditioner, but the present disclosure is not limited thereto.

[0029] Meanwhile, the air conditioner 100 may further include at least one of a ventilation device, an air purifier, a humidifier, and a heater, and may operate in conjunction with operations of the indoor unit 31 and the outdoor unit 21.

[0030] The outdoor unit 21 may include a compressor (not shown) that receives and compresses a refrigerant, an outdoor heat exchanger (not shown) that performs heat exchange between the refrigerant and outdoor air, an accumulator (not shown) that extracts a gaseous refrigerant from the supplied refrigerant and supplies the extracted gaseous refrigerant to the compressor, a four-way valve (not shown) that selects a flow path of the refrigerant based on a heating operation, and an expansion valve (not shown) that expands the supplied refrigerant. In addition, the outdoor unit 21 may further include a plurality of sensors, a valve, an oil collector, etc.

[0031] The outdoor unit 21 may operate the compressor and the outdoor heat exchanger, which are provided therein, to compress or heat-exchange a refrigerant according to a setting and supply the compressed or heat-exchanged refrigerant to the indoor unit 31. The outdoor unit 21 may be driven upon demand by a remote controller (not shown) or the indoor unit 31. In this case, as the cooling / heating capacity varies in correspondence with the indoor unit 31 being driven, the number of operating outdoor units and the number of operating compressors installed in the outdoor unit may also vary.

[0032] In this case, the outdoor unit 21 may supply the compressed refrigerant to the connected indoor unit 31.

[0033] The indoor unit 31 may receive the refrigerant from the outdoor unit 21 to discharge cold or hot air into an indoor space.

[0034] The indoor unit 31 may include an indoor heat exchanger (not shown), an indoor unit fan (not shown), a plurality of sensors (not shown), etc.

[0035] The indoor unit 31 may include a drain pan (not shown) that is disposed adjacent to the indoor heat exchanger to collect water generated by heat exchange in the indoor heat exchanger, and a drain pipe (not shown) that discharges the water collected in the drain pan to the outside.

[0036] The outdoor unit 21 and the indoor unit 31 may communicate with each other. For example, the outdoor unit 21 and the indoor unit 31 may be connected via a communication line to transmit and receive data. The outdoor unit 21 and the indoor unit 31 may be connected, wired or wirelessly, to the remote controller (not shown) so as to operate under the control of the remote controller (not shown).

[0037] A remote control 41 may be connected to the indoor unit 31 so as to transmit a user's control command to the indoor unit 31. The remote control 41 may receive and display state information of the indoor unit 31. In this case, the remote control 41 may communicate with the indoor unit 31 in a wired or wireless manner depending on a connection type.

[0038] FIG. 2 is a schematic diagram of an outdoor unit and an indoor unit according to an embodiment of the present disclosure. Detailed descriptions of content that overlaps with those described in FIG. 1 will be omitted.

[0039] Referring to FIG. 2, the outdoor unit 21 may include a compressor 102 that is configured to compress a refrigerant, a compressor motor 102b that drives the compressor 102, an outdoor heat exchanger 104 that is configured to dissipate heat from the compressed refrigerant, an outdoor blower 105 that includes an outdoor fan 105a disposed at one side of the outdoor heat exchanger 104 to facilitate heat dissipation of the refrigerant and a motor 105b to rotate the outdoor fan 105a, an expansion valve 106 that expands the condensed refrigerant, a cooling / heating switching valve 110 that changes a flow path of the compressed refrigerant, an accumulator 103 that temporarily stores the gaseous refrigerant to remove moisture and foreign matter and supplies the refrigerant with constant pressure to the compressor, etc.

[0040] At least one of an inverter compressor and a constant speed compressor may be used as the compressor 102, for example.

[0041] The expansion valve 106 may be, for example, an electronic expansion valve (EEV).

[0042] The indoor unit 31 may include an indoor heat exchanger 108 that is disposed indoors to perform a cooling / heating function, an indoor blower 109 that includes an indoor fan 109a disposed at one side of the indoor heat exchanger 108 to facilitate heat dissipation of the refrigerant and a motor 109b to rotate the indoor fan 109a, etc.

[0043] The air conditioner 100 may include at least one indoor unit 31. When the air conditioner 100 includes a plurality of indoor units 31, a plurality of indoor heat exchangers 108 may each be connected to the outdoor unit 21.

[0044] In addition, the air conditioner 100 may be configured as a cooler to cool an indoor space, or may be configured as a heat pump to cool or heat an indoor space.

[0045] FIG. 3 is a block diagram of an air conditioner according to an embodiment of the present disclosure.

[0046] Referring to FIG. 3, the air conditioner 100 may include a communication interface 310, a sensor unit 320, a memory 330, a fan drive unit 340 configured to drive the fan 341, a compressor drive unit 350 configured to drive the compressor 102, and / or a controller (or control unit) 370.

[0047] The communication interface 310 may include at least one communication module. For example, the communication interface 310 may be provided in each of the outdoor unit 21 and the indoor unit 31, and the outdoor unit 21 and the indoor unit 31 may transmit and receive data to and from each other.

[0048] The communication method between the outdoor unit 21 and the indoor unit 31 may be, for example, wireless communication such as Wi-Fi, Bluetooth, Beacon, and Zigbee as well as communication using a power line, serial communication (e.g., RS-485 communication), and wired communication through a refrigerant pipe.

[0049] The communication interface 310 may transmit and receive data to and from an external device. For example, the communication interface 310 may establish a connection to a sever connected to an external network to transmit and receive data.

[0050] The sensor unit 320 may include at least one sensor, and may transmit data regarding a detection value detected by the sensor to the controller 370.

[0051] The sensor unit 320 may include a heat exchanger temperature sensor 321. The heat exchanger temperature sensor 321 may be disposed inside / outside the indoor heat exchanger 108 to detect a temperature of the indoor heat exchanger 108. For example, when the heat exchanger temperature sensor 321 is disposed outside the indoor heat exchanger 108, the heat exchanger temperature sensor 321 may be placed outside the heat exchanger or on a pipe. In this case, the heat exchanger temperature sensor 321 may detect the temperature of the indoor heat exchanger 108 by measuring the surface temperature of the heat exchanger or the ambient temperature of the heat exchanger.

[0052] The sensor unit 320 may include a pipe temperature sensor 323. The pipe temperature sensor 323 may detect a temperature of the refrigerant flowing through each pipe of the air conditioner 100. For example, the pipe temperature sensor 323 may be disposed at an inlet side pipe of the indoor unit 31 and / or an outlet side pipe of the indoor unit 31. For example, the pipe temperature sensor 323 may be disposed on a pipe connected to the compressor 102 so as to detect a temperature of the refrigerant entering the compressor 102 (hereinafter referred to as a “suction temperature”) and / or a temperature of the refrigerant exiting the compressor 102 (hereinafter referred to as a “discharge temperature”).

[0053] The sensor unit 320 may include an indoor temperature sensor 325 to detect an indoor temperature and / or an outdoor temperature sensor 327 to detect an outdoor temperature.

[0054] The sensor unit 320 may include a pressure sensor (not shown). The pressure sensor (not shown) may detect a pressure of the gaseous refrigerant flowing through each pipe of the air conditioner 100. For example, the pressure sensor may be disposed in a pipe connected to the compressor 102 so as to detect a pressure of the refrigerant entering the compressor 102 (hereinafter referred to as a “suction pressure”) and / or a pressure of the refrigerant exiting the compressor 102 (hereinafter referred to as a “discharge pressure”).

[0055] The memory 330 may store data of reference values related to the operation of each component provided in the air conditioner 100.

[0056] The memory 330 may store programs for processing and controlling each signal in the controller 370, and may store processed data and data to be processed. For example, the memory 330 may store application programs designed for the purpose of performing various tasks that can be processed by the controller 370 and, upon request of the controller 370, may selectively provide some of the stored application programs.

[0057] The memory 330 may include, for example, at least one of volatile memory (e.g., DRAM, SRAM, SDRAM, etc.) and non-volatile memory (e.g., flash memory, hard disk drive (HDD), solid-state drive (SSD), etc.).

[0058] The fan drive unit 340 may drive the fan 341 provided in the air conditioner 100. For example, the fan 341 may include an outdoor fan 105a and / or an indoor fan 109a.

[0059] The fan drive unit 340 may include a rectifier (not shown) that rectifies alternating current (AC) power into direct current (DC) power and outputs the rectified DC power, a DC terminal capacitor (not shown) that stores a pulsating voltage from the rectifier, an inverter (not shown) that includes a plurality of switching elements to convert smoothed DC power into three-phase AC power of a predetermined frequency and output the three-phase AD power, and / or a motor that drives the fan 341 based on the three-phase AC power output from the inverter.

[0060] Meanwhile, the fan drive unit 340 may have separate components for driving the outdoor fan 105a and indoor fan 109a. For example, the air conditioner 100 may include a first fan drive unit to drive the outdoor fan 105a, and a second fan drive unit to drive the indoor fan 109a.

[0061] The compressor drive unit 350 may drive the compressor 102. The compressor drive unit 350 may include a rectifier (not shown) that rectifies AC power into DC power and outputs the rectified DC power, a DC terminal capacitor (not shown) that stores a pulsating voltage from the rectifier, an inverter (not shown) that includes a plurality of switching elements to convert smoothed DC power into three-phase AC power of a predetermined frequency and output the three-phase AD power, and / or a compressor motor 102b that drives the compressor 102 based on the three-phase AC power output from the inverter.

[0062] A vane 360 may be disposed at an outlet of the indoor unit 31 through which air moved by the indoor fan 109a is discharged. The air conditioner 100 may further include a vane motor to drive the vane 360, a link connected between the vane 360 and the vane motor, etc. For example, when the link is rotated by the rotation of the vane motor, a direction in which the vane 360 faces may be changed according to the rotation of the link. In this case, as the direction that the vane 360 faces changes, a direction in which air is discharged through the outlet of the indoor unit 31 (hereinafter referred to as an “airflow direction”) may also be changed. The vane motor may be implemented as a step motor, but is not limited thereto.

[0063] The controller 370 may control the overall operation of the air conditioner 100. The controller 370 may be connected to each component provided in the air conditioner 100, and may control the overall operation of each component by transmitting and / or receiving a signal to and from each component.

[0064] The controller 370 may control the operation of the fan drive unit 340 to change a rotational speed of the fan 341. For example, under the control of the controller 370, the fan drive unit 340 may change the rotational speed of the outdoor fan 105a by changing a frequency of three-phase AC power output to the outdoor fan motor 105b. For example, under the control of the controller 370, the fan drive unit 340 may change the rotational speed of the indoor fan 109a by changing a frequency of three-phase AC power output to the indoor fan motor 109b.

[0065] The controller 370 may control the operation of the compressor drive unit 350 to change an operating frequency of the compressor 102. For example, under the control of the controller 370, the compressor drive unit 350 may change the operating frequency of the compressor 102 by changing a frequency of three-phase AC power output to the compressor motor 102b.

[0066] The controller 370 may change the airflow direction. For example, upon changing the airflow direction, the controller 370 may rotate the vane motor to change a direction in which the vane 360 faces.

[0067] The controller 370 may be provided not only in the outdoor unit 21, but also in the indoor unit 31, a central controller (not shown) that controls the operation of the outdoor unit 21 and / or the indoor unit 31.

[0068] The controller 370 may include at least one processor, and may control the overall operation of the air conditioner 100 using the processor included therein. Here, the processor may be a general processor such as a central processing unit (CPU). Alternatively, the processor may be a dedicated device such as an ASIC or another hardware-based processor.

[0069] The controller 370 may obtain data related to each component provided in the air conditioner 100. In this case, in consideration of the computational load, the controller 370 may obtain data related to each component provided in the air conditioner 100 at regular time intervals according to a predetermined period.

[0070] The controller 370 may perform various calculations based on the obtained data, and may control the overall operation of each component provided in the air conditioner 100 based on the calculation results.

[0071] Data related to each component provided in the air conditioner 100 may include, for example, the operating frequency of the compressor 102, the suction temperature of the compressor 102, the discharge temperature, the suction pressure, the discharge pressure, the pipe temperature at an inlet side of the indoor unit 31, the pipe temperature at an outlet side of the indoor unit 31, the indoor temperature, the outdoor temperature, the opening degree of the electronic expansion valve (EEV), and the like.

[0072] Meanwhile, the air conditioner 100 may further include an input device (not shown) capable of receiving a user input. For example, when a user input is received through the input device (e.g., a touch panel, a key, etc.), the air conditioner 100 may perform an operation corresponding to the user input.

[0073] The air conditioner 100 may further include an output device (not shown) to output a message regarding an operating state of the air conditioner 100. For example, the output device may include a display device such as a display or a light emitting diode (LED), and / or an audio device such as a speaker or a buzzer.

[0074] FIGS. 4 to 6 are flowcharts illustrating a method of operating an air conditioner according to various embodiments of the present disclosure.

[0075] Referring to FIG. 4, in operation S410, the air conditioner 100 may determine whether a temperature condition for initiating a function to remove foreign matter or contaminants present on the surface of the indoor heat exchanger 108 (hereinafter referred to as a “foreign matter removal function”) is satisfied. For example, in response to receiving a user input for initiating the foreign matter removal function through a touch panel provided on the remote control 41, the air conditioner 100 may determine the temperature condition for initiating the foreign matter removal function. For example, the air conditioner 100 may determine the temperature condition for initiating the foreign matter removal function according to a preset time interval for performing the foreign matter removal function.

[0076] The temperature condition for initiating the foreign matter removal function may correspond to whether an indoor temperature and an outdoor temperature are each within a predetermined temperature range. For example, the air conditioner 100 may determine that the temperature condition for initiating the foreign matter removal function is satisfied when the indoor temperature corresponds to a first temperature range above zero and the outdoor temperature corresponds to a second temperature range above zero. Here, the first temperature range and the second temperature range may be temperature ranges in which a certain cooling performance can be ensured when the air conditioner 100 is operated as a cooler. For example, the first temperature range may be 21° C. to 32° C., and the second temperature range may be 21° C. to 37° C.

[0077] In operation S420, when the temperature condition for initiating the foreign matter removal function is not satisfied, the air conditioner 100 may notify a user that removal of foreign matter is unavailable. For example, the air conditioner 100 may output, via a display provided on the remote control 41, an indicator indicating that the foreign matter removal function cannot be started. Meanwhile, the air conditioner 100 may continue to perform the currently performed operation when the temperature condition for initiating the foreign matter removal function is not satisfied.

[0078] In operation S430, when the temperature condition for initiating the foreign matter removal function is satisfied, the air conditioner 100 may perform an operation related to condensation of moisture contained in indoor air (hereinafter referred to as a “condensation operation”). Here, the condensation operation may refer to an operation of the air conditioner 100 that causes moisture contained in indoor air to form water droplets on the surface of the indoor heat exchanger 108. For example, the air conditioner 100 may perform the condensation operation for a preset time for the condensation operation (hereinafter referred to as a “condensation time”).

[0079] When it is determined to perform the condensation operation, the air conditioner 100 may check whether the compressor 102 is being driven. In this case, when the compressor 102 is not driven, the air conditioner 100 may control the compressor drive unit 350 to start the compressor 102. For example, when the air conditioner 100 starts the compressor 102, the air conditioner 100 may control the operation of each component according to preset conditions so that an operating frequency of the compressor 102 reaches a predetermined frequency. The air conditioner 100 may control the operation of each component based on a cooling mode for cooling an indoor space. For example, when starting the compressor 102, the air conditioner 100 may open the electronic expansion valve (EEV) according to a preset opening degree. Meanwhile, the air conditioner 100 may determine that a refrigerant cycle is stabilized when the compressor 102 can sufficiently compress the introduced refrigerant into a high-temperature, high-pressure gaseous refrigerant depending on the purpose.

[0080] The air conditioner 100 may determine a target temperature for the temperature of the indoor heat exchanger 108 related to condensation (hereinafter referred to as a “condensation target temperature”). The target condensation temperature may be a temperature at which moisture contained in indoor air forms water droplets on the surface of the indoor heat exchanger 108, but the water droplets do not freeze. The condensation target temperature may correspond to the indoor temperature. For example, the target condensation temperature may be a predetermined temperature (e.g., 18° C.) associated with condensation that is lower than a current temperature of the indoor space (or a current indoor temperature). A description is given based on the temperature of the indoor heat exchanger 108, but the present disclosure is not limited thereto. For example, the air conditioner 100 may perform an operation based on the lower temperature between a pipe temperature at an inlet side and a pipe temperature at an outlet side of the indoor heat exchanger 108. For example, the air conditioner 100 may perform an operation based on an intermediate value between the pipe temperature at the inlet side and the pipe temperature at the outlet side of the indoor heat exchanger 108.

[0081] The air conditioner 100 may adjust the operating frequency of the compressor 102 based on a current temperature of the indoor heat exchanger 108 and the target condensation temperature. For example, the air conditioner 100 may adjust the operating frequency of the compressor 102 based on a difference between the current temperature of the indoor heat exchanger 108 and the target condensation temperature. In this case, the greater the difference between the current temperature of the indoor heat exchanger 108 and the target condensation temperature, the higher the operating frequency of the compressor 102 may be.

[0082] In one embodiment, the air conditioner 100 may adjust a predetermined temperature associated with determining the target condensation temperature. The air conditioner 100 may receive data regarding temperature and humidity corresponding to a predetermined location and a predetermined date and time from a server connected to a network via the communication interface 310. The predetermined location may correspond to an installation location of the air conditioner 100. The predetermined date and time may correspond to a time, date, and / or a period corresponding to initiation of the foreign matter removal function.

[0083] The air conditioner 100 may determine a predetermined temperature based on data regarding temperature and humidity. The data regarding temperature and humidity may include a dry-bulb temperature, relative humidity, and / or a dew point temperature. For example, when data regarding temperature and humidity includes a dry-bulb temperature and relative humidity, the air conditioner 100 may determine a dew point temperature corresponding to the dry-bulb temperature and the relative humidity based on a psychrometric chart.

[0084] The air conditioner 100 may set a predetermined temperature based on a difference between the indoor temperature and the dew point temperature. Referring to FIG. 7, a dew point temperature 700 corresponding to the indoor temperature may be determined based on data regarding temperature and humidity. In this case, the air conditioner 100 may determine a temperature that is a certain level higher than the lowest value of the difference between the indoor temperature and the dew point temperature as the predetermined temperature. For example, the difference between the indoor temperature and the dew point temperature may be at its minimum when the indoor temperature is 32° C. and the dew point temperature is 16.7° C. In this case, the air conditioner 100 may determine the predetermined temperature to be 17° C. that is higher than the difference between the indoor temperature and the dew point temperature of 15.3° C. by not less than 1° C. and less than 2° C.

[0085] Meanwhile, the air conditioner 100 may determine whether to perform the foreign matter removal function based on data received from the server. For example, based on the data received from the server, the air conditioner 100 may check a dry-bulb temperature, relative humidity, a dew point temperature, and the like at a particular date and time. In this case, when it is determined that moisture condensation occurs more than a predetermined reference based on the dry-bulb temperature, the relative humidity, the dew point temperature, and the like at the particular date and time, the air conditioner 100 may determine to perform the foreign matter removal function. For example, the air conditioner 100 may determine to perform the foreign matter removal function based on a difference between the indoor temperature and the dew point temperature being less than a predetermined reference.

[0086] The air conditioner 100 may output, via the output device, a message recommending the execution of the foreign matter removal function. For example, based on the difference between the indoor temperature and the dew point temperature being less than a first reference (e.g., 10° C.), the air conditioner 100 may output, via the display provided on the remote control 41, a recommended message that recommends the execution of the foreign matter removal function. By contrast, based on the difference between the indoor temperature and the dew point temperature being greater than or equal to a second reference (e.g., 18° C.), the air conditioner 100 may output, via the display provided on the remote control 41, a message notifying that the execution of the foreign matter removal function is inappropriate.

[0087] While performing the condensation operation, the air conditioner 100 may control the vane 360 so that air is discharged according to a preset airflow direction for the condensation operation. For example, the airflow direction may include an indirect airflow in which the airflow is formed in the forward direction of the air conditioner 100, a direct airflow in which the airflow is formed in the downward direction of the air conditioner 100, and an angled airflow that corresponds between the indirect airflow and the direct airflow. The air conditioner 100 may increase an angle of the vane 360 to generate the indirect airflow. Here, the angle of the vane 360 may be an angle formed by the vane 360 and a predetermined direction perpendicular to the ground. For example, the indirect airflow may be formed when the angle of the vane 360 is at its maximum. In addition, the air conditioner 100 may reduce the angle of the vane 360 to generate the direct airflow. For example, the direct airflow may be formed when the angle of the vane 360 is at its minimum. In this case, while performing the condensation operation, the air conditioner 100 may control the vane 360 so that air is discharged according to the angled airflow.

[0088] While performing the condensation operation, the air conditioner 100 may rotate the indoor fan 109a at a preset rotational speed in response to the condensation operation. For example, while performing the condensation operation, the air conditioner 100 may rotate the indoor fan 109a at a rotational speed corresponding to a second level (level 2) of four preset rotational speed levels. Here, as the level of rotational speed increases, air volume, which is the flow rate of air moved by the indoor fan 109a, may increase as the rotational speed increases. In the present disclosure, the rotational speed is described as being divided into four levels, but is not limited thereto.

[0089] In one embodiment, the air conditioner 100 may determine whether to perform the condensation operation. For example, the air conditioner 100 may be preset to perform the condensation operation upon performing an operation to remove foreign matter. For example, the air conditioner 100 may determine whether to perform the condensation operation in response to a user input received through the touch panel provided on the remote control 41. In this case, when there is a history of previously receiving a user input for executing the condensation operation, the air conditioner 100 may determine whether to perform the condensation operation based on the history.

[0090] In operation S440, when the condensation operation is completed, the air conditioner 100 may perform an operation related to freezing of moisture (hereinafter referred to as a “freezing operation”). Here, the freezing operation may refer to an operation of the air conditioner 100 that causes ice to form on the surface of the indoor heat exchanger 108. Hereinafter, the freezing operation will be described in detail with reference to FIG. 5.

[0091] Referring to FIG. 5, in operation S510, the air conditioner 100 may check whether an opening degree of the expansion valve 106 is less than a preset opening degree related to initiation of the freezing operation (hereinafter referred to as a “freezing start opening degree”). Here, the freezing start opening degree may be smaller than the opening degree of the expansion valve 106 when the startup of the compressor 102 is complete (hereinafter referred to as a “start opening degree”).

[0092] In operation S520, based on the opening degree of the expansion valve 106 exceeding the freezing start opening degree, the air conditioner 100 may change the opening degree of the expansion valve 106 to the freezing start opening degree.

[0093] In operation S530, the air conditioner 100 may control the compressor 102 according to a target temperature for the temperature of the indoor heat exchanger 108 related to freezing (hereinafter referred to as a “freezing target temperature”). Here, the freezing target temperature may be determined in a sub-zero temperature range (below 0° C.). For example, the freezing target temperature may be preset to a predetermined temperature (e.g., −19° C.) at which moisture condensed in the indoor heat exchanger 108 is sufficiently frozen to a certain level or higher.

[0094] The air conditioner 100 may control the operating frequency of the compressor 102 based on a difference between the current temperature of the indoor heat exchanger 108 and the freezing target temperature. For example, the air conditioner 100 may control the compressor drive unit 350 to increase the operating frequency of the compressor 102 when the current temperature of the indoor heat exchanger 108 is greater than the freezing target temperature.

[0095] In operation S540, the air conditioner 100 may determine whether the current temperature of the indoor heat exchanger 108 is less than a preset limit temperature. Here, the limit temperature may be preset to a temperature greater than the freezing target temperature. For example, the limit temperature may be preset to a sub-zero temperature of −10° C. greater than the freezing target temperature of −19° C.

[0096] In operation S550, based on the current temperature of the indoor heat exchanger 108 being less than the preset limit temperature, the air conditioner 100 may adjust a preset maximum frequency for the operating frequency of the compressor 102. For example, the maximum operating frequency of the compressor 102 may be preset to a first frequency (e.g., 90 Hz) in a state where the current temperature of the indoor heat exchanger 108 is at or above the limit temperature of −10° C. In this case, based on the current temperature of the indoor heat exchanger 108 being less than the preset limit temperature of −10° C., the air conditioner 100 may change the maximum frequency for the operating frequency of the compressor 102 to a second frequency (e.g. 75 Hz) that is lower than the first frequency by a predetermined frequency (e.g., 15 Hz). Accordingly, it is possible to prevent the temperature of the indoor heat exchanger 108 from being excessively lowered. In addition, by preventing the operation of the compressor 102 from stopping due to an increase in compression ratio of the compressor 102, the freezing operation may be performed such that moisture condensed in the indoor heat exchanger 108 is sufficiently frozen.

[0097] In operation S560, the air conditioner 100 may determine whether a minimum time related to performing the freezing operation (hereinafter referred to as a “minimum freezing time”) has elapsed since the initiation of the freezing operation. Here, the minimum freezing time may be longer than the condensation time during which the condensation operation is performed. For example, the condensation time may be preset to 5 minutes, and the minimum freezing time may be preset to 10 minutes.

[0098] In operation S570, based on the minimum freezing time having elapsed, the air conditioner 100 may determine whether the temperature of the indoor heat exchanger 108 is less than or equal to the freezing target temperature. In one embodiment, when the temperature of the indoor heat exchanger 108 is maintained at or below the freezing target temperature for a predetermined time (e.g., 10 seconds) or more, the air conditioner 100 may determine that the temperature of the indoor heat exchanger 108 is less than or equal to the freezing target temperature.

[0099] In operation S580, based on the temperature of the indoor heat exchanger 108 being greater than the freezing target temperature, the air conditioner 100 may determine whether a maximum time related to performing the freezing operation (hereinafter referred to as a “maximum freezing time”) has elapsed. For example, the maximum freezing time may be preset to 15 minutes.

[0100] The air conditioner 100 may end or terminate the freezing operation when at least one of the following occurs: the temperature of the indoor heat exchanger 108 is less than or equal to the freezing target temperature after the minimum freezing time has elapsed; or the maximum freezing time has elapsed.

[0101] Meanwhile, while performing the freezing operation, the air conditioner 100 may control the vane 360 so that air is discharged through the outlet of the indoor unit 31 in an airflow direction different from the preset airflow direction for the condensation operation. For example, while performing the freezing operation, the air conditioner 100 may control the vane 360 so that air is discharged according to the indirect airflow. For example, while performing the freezing operation, the air conditioner 100 may control the vane 360 to close the outlet of the indoor unit 31.

[0102] While performing the freezing operation, the air conditioner 100 may set a rotational speed of the outdoor fan 105a to a maximum rotational speed. While performing the freezing operation, the air conditioner 100 may adjust the rotational speed of the indoor fan 109a. For example, upon initiating the freezing operation, the air conditioner 100 may rotate the indoor fan 109a at a rotational speed corresponding to a first level (level 1) of the four preset rotational speed levels.

[0103] In this case, when a pipe temperature at an inlet side of the indoor unit 31 is greater than or equal to a preset upper limit temperature after a predetermined time (e.g., 12 minutes) has elapsed since the initiation of the freezing operation, the air conditioner 100 may control the fan drive unit 340 so that the rotational speed of the indoor fan 109a is reduced below the current rotational speed. Here, the preset upper limit temperature may be a temperature (e.g., −5° C.) corresponding to the highest temperature within a temperature range in which freezing of moisture condensed in the indoor heat exchanger 108 can occur. Meanwhile, while performing the freezing operation, the air conditioner 100 may monitor the pipe temperature at the inlet side of the indoor unit 31 according to a predetermined time interval (e.g., 100 seconds). In this case, when the difference in the pipe temperature at the inlet side of the indoor unit 31 detected according to the predetermined time interval is less than a preset difference (e.g., 0.2° C.), the air conditioner 100 may control the fan drive unit 340 so that the rotational speed of the indoor fan 109a is reduced below the current rotational speed. In the present disclosure, it is described that the rotational speed of the indoor fan 109a is adjusted based on the inlet pipe temperature of the indoor unit 31, but is not limited thereto.

[0104] Referring back to FIG. 4, in operation S450, when the freezing operation is completed, the air conditioner 100 may perform a defrosting operation to melt the ice formed on the surface of the indoor heat exchanger 108. The air conditioner 100 may perform the defrosting operation for a preset time for the defrosting operation (hereinafter referred to as a “defrosting time”). For example, the defrosting time may be shorter than the condensation time and the minimum freezing time.

[0105] While performing the defrosting operation, the air conditioner 100 may rotate the indoor fan 109a at a rotational speed corresponding to the first or second level of the four preset rotational speed levels.

[0106] The air conditioner 100 may set the operating frequency of the compressor 102 to a preset minimum frequency while performing the defrosting operation. Here, the minimum frequency may correspond to the lowest value of the operating frequency that can be lowered while the compressor 102 is being driven. While performing the defrosting operation, the air conditioner 100 may set the opening degree of the expansion valve 106 to a preset minimum opening degree. For example, the minimum opening degree may be the start opening degree or the freezing start opening degree. For example, the minimum opening degree may be an opening degree that is smaller than the start opening degree and the freezing start opening degree. The air conditioner 100 may set the rotational speed of the outdoor fan 105a to the minimum rotational speed while performing the defrosting operation.

[0107] As the operating frequency of the compressor 102, the opening degree of the expansion valve 106, and the rotational speed of the outdoor fan 105a are set to their minimum values, the refrigerant remaining in the indoor unit 31, a pipe connecting the indoor unit 31 and the outdoor unit 21, and the like may be recovered to the outdoor unit 102 as fully as possible. Accordingly, it is possible to prevent problems such as damage to the compressor 102 and reduced efficiency caused when liquid refrigerant is introduced into the compressor 102.

[0108] Meanwhile, the air conditioner 100 may stop the operation of the outdoor unit 21 when the defrosting time has elapsed. For example, the air conditioner 100 may terminate the operation of the compressor 102. For example, the air conditioner 100 may stop the rotation of the outdoor fan 105a.

[0109] In operation S460, when the defrosting time has elapsed, the air conditioner 100 may perform an operation (hereinafter referred to as a “drying operation”) to remove moisture condensed, frozen, and defrosted in the indoor heat exchanger 108. The air conditioner 100 may perform any one of a full drying operation in which moisture is completely removed from the indoor heat exchanger 108 or a partial drying operation in which moisture is partially removed from the indoor heat exchanger 108. Hereinafter, the drying operation will be described in detail with reference to FIG. 6.

[0110] Referring to FIG. 6, in operation S610, the air conditioner 100 may determine whether an operation for foreign matter removal has been performed repeatedly. For example, the air conditioner 100 may determine whether the condensation operation, the freezing operation, and the defrosting operation have each been performed at least two times.

[0111] In operation S620, when the operation for foreign matter removal has not been performed repeatedly, the air conditioner 100 may check whether the temperature of the indoor heat exchanger 108 has reached the freezing target temperature while performing the freezing operation.

[0112] In operation S630, when the freezing operation is terminated while the temperature of the indoor heat exchanger 108 is above the freezing target temperature, the air conditioner 100 may determine whether the freezing operation is terminated while the temperature of the indoor heat exchanger 108 is below a predetermined reference temperature that is greater than the freezing target temperature. For example, when the freezing target temperature is −19° C., the reference temperature may be preset to −17° C. greater than −19° C.

[0113] In operation S640, the air conditioner 100 may perform the partial drying operation when the freezing operation is terminated while the temperature of the indoor heat exchanger 108 is at or above the reference temperature.

[0114] In one embodiment, upon performing the partial drying operation, the air conditioner 100 may rotate the indoor fan 109a at a rotational speed corresponding to a third level (level 3) of the four preset rotational speed levels for a first preset time for the partial drying operation. In this case, the air conditioner 100 may control the vane 360 so that air is discharged according to a preset airflow direction for the partial drying operation. For example, while performing the partial drying operation, the air conditioner 100 may control the vane 360 so that air is discharged according to the indirect airflow.

[0115] In operation S650, the air conditioner 100 may determine to repeat the operation for foreign matter removal.

[0116] In operation S660, the air conditioner 100 may perform the full drying operation when the freezing operation is terminated while the temperature of the indoor heat exchanger 108 is below the reference temperature.

[0117] In one embodiment, upon performing the full drying operation, the air conditioner 100 may rotate the indoor fan 109a at a rotational speed corresponding to a fourth level (level 4) of the four preset rotational speed levels for a second time longer than the first time. In this case, the air conditioner 100 may change a direction in which the vane 360 faces so that the airflow direction is continuously changed during the second time. For example, the air conditioner 100 may drive the vane motor so that the airflow direction continuously alternates between the direct airflow and the indirect airflow during the second time. For example, the air conditioner 100 may control so that the direction in which the vane 360 faces alternates between left and right. Accordingly, moisture can be uniformly dried in the entire area of the indoor heat exchanger 108.

[0118] Meanwhile, when the second time has elapsed, the air conditioner 100 may rotate the indoor fan 109a at a rotational speed corresponding to the second level of the four preset rotational speed levels for a third time shorter than the second time. In this case, the air conditioner 100 may control the vane 360 so that air is discharged according to the angled airflow during the third time.

[0119] In operation S660, the air conditioner 100 may determine to terminate the operation for foreign matter removal.

[0120] Referring back to FIG. 4, in operation S470, the air conditioner 100 may check whether to terminate the operation for foreign matter removal. Upon repeatedly performing the operation for foreign matter removal, the air conditioner 100 may perform the condensation operation, the freezing operation, and / or the drying operation again.

[0121] FIG. 8 is a graph showing the temperature of the indoor heat exchanger 108. Referring to FIG. 8, the air conditioner 100 may perform the condensation operation until a time point t1, the freezing operation from the time point t1 to a time point t2, the defrosting operation from the time point t2 to a time point t3, and the drying operation from the time point t3.

[0122] When an indoor temperature T0 is within the first temperature range of 21° C. to 32° C., the temperature of the indoor heat exchanger 108 may also correspond to the indoor temperature T0. In this case, while the air conditioner 100 performs the condensation operation, the temperature of the indoor heat exchanger 108 may be lowered to a temperature T1 below the dew point temperature. The temperature of the indoor heat exchanger 108 may gradually decrease while the air conditioner 100 performs the freezing operation. As the temperature of the indoor heat exchanger 108 reaches a freezing target temperature T2, the freezing operation may be terminated. Meanwhile, the temperature of the indoor heat exchanger 108 may gradually increase while the air conditioner 100 performs the defrosting operation and the drying operation.

[0123] FIG. 9 is a graph showing the rotational speed of the indoor fan 109a. Referring to FIG. 9, while performing the condensation operation, the air conditioner 100 may rotate the indoor fan 109a at a rotational speed corresponding to level 2 (f2) of the four preset rotational speed levels. While performing the freezing operation, the air conditioner 100 may rotate the indoor fan 109a at a rotational speed corresponding to level 1 (f1), which is slower (or lower) than the rotational speed (f2) in the condensation operation. While performing the defrosting operation, the air conditioner 100 may rotate the indoor fan 109a at a rotational speed corresponding to level 2 (f2), which is faster (or higher) than the rotational speed (f1) in the freezing operation.

[0124] The air conditioner 100 may rotate the indoor fan 109a at a rotational speed corresponding to level 4 (f4), which is the highest rotational speed, from a time point t3, at which the full drying operation is performed, to a time point t4. Meanwhile, the air conditioner 100 may rotate the indoor fan 109a at a rotational speed corresponding to level 2 (f2) again from the time point t4 at which the full drying operation is performed.

[0125] As described above, according to at least one embodiment of the present disclosure, it is possible to effectively remove foreign matter adsorbed on the indoor heat exchanger 108 only by temperature sensing.

[0126] Additionally, according to at least one embodiment of the present disclosure, it is possible to prevent damage to the compressor 102 that may occur while removing foreign matter adsorbed on the indoor heat exchanger 108.

[0127] Additionally, according to at least one embodiment of the present disclosure, as the operation of removal of foreign matter adsorbed on the indoor heat exchanger 108 is repeated according to whether the foreign matter adsorbed on the indoor heat exchanger 108 is sufficiently removed suitable for the purpose, it is possible to remove foreign matter adsorbed on the indoor heat exchanger 108 in a more effective manner.

[0128] The accompanying drawings are used to help easily understand various embodiments of the present disclosure and it should be understood that the embodiments presented herein are not limited by the accompanying drawings, and the present disclosure should be construed to extend to any alterations, equivalents and substitutes in addition to those which are particularly set out in the accompanying drawings.

[0129] Similarly, while operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous.

[0130] It will be apparent that, although the preferred embodiments have been shown and described above, the present disclosure is not limited to the above-described specific embodiments, and various modifications and variations can be made by those skilled in the art without departing from the scope of the present disclosure as defined by the appended claims. Thus, it is intended that the modifications and variations should not be understood independently of the technical idea or perspective of the present disclosure.

Claims

1. An air conditioner, comprising:a compressor configured to compress and discharge a refrigerant;an indoor heat exchanger configured to exchange heat between the refrigerant and indoor air;a sensor configured detect a temperature of the indoor heat exchanger and an indoor temperature; anda controller, wherein the controller is configured to:perform a primary control of the compressor based on a first target temperature for the temperature of the indoor heat exchanger, the first target temperature corresponding to the indoor temperature;when the primary control is terminated, perform a secondary control of the compressor based on a second target temperature below zero for the temperature of the indoor heat exchanger, the second target temperature being less than the first target temperature;when the secondary control is terminated, set an operating frequency of the compressor to a preset minimum frequency for a predetermined period of time; andwhen the predetermined period of time has elapsed, determine whether to repeat the primary control based on a condition for the secondary control.

2. The air conditioner of claim 1, further comprising:an expansion valve configured to expand the refrigerant flowing into the indoor heat exchanger;an outdoor heat exchanger configured to exchange heat between the refrigerant and outdoor air; andan outdoor fan disposed adjacent to the outdoor heat exchanger, wherein the controller is further configured to:set an opening degree of the expansion valve to a preset minimum opening degree for the predetermined period of time; andset a rotational speed of the outdoor fan to a preset minimum rotational speed for the predetermined period of time.

3. The air conditioner of claim 1, wherein the controller is further configured to:determine not to repeat the primary control when the secondary control is terminated while the temperature of the indoor heat exchanger is below a predetermined reference temperature which is greater than the second target temperature; anddetermine to repeat the primary control when the secondary control is terminated while the temperature of the indoor heat exchanger is at or above the reference temperature.

4. The air conditioner of claim 3, wherein while performing the secondary control, the controller is configured to:based on the secondary control being performed for a preset minimum period of time or more, check whether the temperature of the indoor heat exchanger is less than or equal to the second target temperature;based on the temperature of the indoor heat exchanger being greater than the second target temperature, check whether the secondary control is performed for a preset maximum period of time or more; andterminate the secondary control based on at least one of the temperature of the indoor heat exchanger being less than or equal to the second target temperature or the secondary control being performed for the maximum period of time or more.

5. The air conditioner of claim 3, wherein while performing the secondary control, the controller is configured to:based on the temperature of the indoor heat exchanger being greater than or equal to a predetermined limit temperature which is higher than the reference temperature, maintain a preset maximum frequency for the operating frequency to a first frequency; andbased on the temperature of the indoor heat exchanger being less than the limit temperature, change the maximum frequency to a second frequency lower than the first frequency.

6. The air conditioner of claim 1, further comprising an indoor fan disposed adjacent to the indoor heat exchanger, wherein the controller is further configured to:based on a determination to repeat the primary control, control the indoor fan to rotate at a first rotational speed for a first period of time; andbased on a determination not to repeat the primary control, control the indoor fan to rotate at a second rotational speed higher than the first rotational speed for a second period of time longer than the first period of time.

7. The air conditioner of claim 6, wherein based on the second period of time having elapsed, the controller is further configured to control the indoor fan to rotate at a third rotational speed lower than the first rotational speed for a third period of time shorter than the second period of time.

8. The air conditioner of claim 7, further comprising a vane disposed at an outlet through which air moved by the indoor fan is discharged, wherein the controller is configured to control the vane to continuously change a direction in which the air is discharged through the outlet during the second period of time.

9. The air conditioner of claim 1, further comprising an outdoor temperature sensor configured to detect an outdoor temperature, wherein the controller is further configured to:perform the primary control based on the indoor temperature corresponding to a first temperature range above zero and the outdoor temperature corresponding to a second temperature range above zero; anddetermine that performing the primary control is unavailable based on at least one of the indoor temperature not falling within the first temperature range or the outdoor temperature not falling within the second temperature range.

10. The air conditioner of claim 1, further comprising a communication interface configured to communicate with an external device, wherein the controller is further configured to:calculate a dew point temperature based on data regarding temperature and humidity corresponding to a predetermined location and a predetermined date and time received through the communication interface; anddetermine the first target temperature based on a difference between the calculated dew point temperature and the indoor temperature.

11. The air conditioner of claim 1, wherein the temperature of the indoor heat exchanger corresponds to a lower temperature between a pipe temperature at an inlet side and a pipe temperature at an outlet side of the indoor heat exchanger or an intermediate value between the pipe temperature at the inlet side and the pipe temperature at the outlet side of the indoor heat exchanger.

12. The air conditioner of claim 1, further comprising:an indoor fan disposed adjacent to the indoor heat exchanger; anda vane disposed at an outlet through which air moved by the indoor fan is discharged, wherein while performing the primary control, the controller is configured to control the vane so that a direction in which the air is discharged is fixed to a first direction.

13. The air conditioner of claim 12, wherein while performing the secondary control, the controller is configured to control the vane so that the direction in which the air is discharged is raised to a second direction higher than the first direction or to control the vane to close the outlet.

14. The air conditioner of claim 1, wherein the primary control comprises a condensation operation, which comprises an operation of the air conditioner that causes moisture contained in the indoor air to form water droplets on a surface of the indoor heat exchanger.

15. The air conditioner of claim 14, wherein the secondary control comprises a freezing operation, which comprises an operation of the air conditioner that causes freezing of moisture condensed in the indoor heat exchanger.

16. The air conditioner of claim 15, wherein when the secondary control is terminated, the operating frequency of the compressor is set to the preset minimum frequency for the predetermined period of time to perform a defrosting operation.

17. The air conditioner of claim 16, wherein the air conditioner further performs a drying operation to remove from the indoor heat exchanger moisture condensed, frozen, and defrosted.

18. An air conditioner, comprising:a compressor configured to compress and discharge a refrigerant;an indoor heat exchanger configured to exchange heat between the refrigerant and indoor air;a sensor configured detect a temperature of the indoor heat exchanger and an indoor temperature; anda controller, wherein when a temperature condition for initiating a foreign matter removal function is satisfied, the controller is configured to:perform a primary control of the compressor based on a first target temperature for the temperature of the indoor heat exchanger, the first target temperature corresponding to the indoor temperature, wherein the primary control comprises a condensation operation, which comprises an operation of the air conditioner that causes moisture contained in the indoor air to form water droplets on a surface of the indoor heat exchanger;when the primary control is terminated, perform a secondary control of the compressor based on a second target temperature below zero for the temperature of the indoor heat exchanger, the second target temperature being less than the first target temperature, wherein the secondary control comprises a freezing operation, which comprises an operation of the air conditioner that causes freezing of moisture condensed in the indoor heat exchanger;when the secondary control is terminated, set an operating frequency of the compressor to a preset minimum frequency for a predetermined period of time, wherein the operating frequency of the compressor is set to the preset minimum frequency for the predetermined period of time to perform a defrosting operation; andwhen the predetermined period of time has elapsed, determine whether to repeat the primary control based on a condition for the secondary control.

19. The air conditioner of claim 18, wherein the air conditioner further performs a drying operation to remove from the indoor heat exchanger moisture condensed, frozen, and defrosted.

20. The air conditioner of claim 18, wherein the controller is further configured to:determine not to repeat the primary control when the secondary control is terminated while the temperature of the indoor heat exchanger is below a predetermined reference temperature which is greater than the second target temperature; anddetermine to repeat the primary control when the secondary control is terminated while the temperature of the indoor heat exchanger is at or above the reference temperature.

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