AIR CONDITIONER PERFORMING NOISE PREVENTION CONTROL, AND CONTROL METHOD THEREFOR

Description

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation application, claiming priority under § 111 (a), of International Application No. PCT/KR2023/021832, filed on Dec. 28, 2023, which is based on and claims the benefit of Korean Patent Application No.: 10-2023-0005644, filed Jan. 13, 2023, in the Korean Intellectual Property Office, the disclosures of which are incorporated by reference herein in their entireties.

TECHNICAL FIELD

An embodiment of the present disclosure provides an air conditioner that performs noise prevention control, a method of controlling the air conditioner, and a computer-readable recording medium having recorded thereon a program for performing the method of controlling the air conditioner.

BACKGROUND ART

The air conditioner is equipped with a fan for discharging cooled air or heated air. The indoor unit of the air conditioner uses the fan to discharge the cooled air or heated air into an air conditioning space. More than a certain level of noise is accompanied by operation of the fan. The higher the revolution per minute (rpm) of the fan, the higher the noise level of the fan.

In the meantime, when the air conditioner is halted from an operation state, the rpm of the fan decreases to 0 from a certain value. In the case that the rpm of the fan decreases, an abrupt change in rpm causes significant reduction in noise level, and the significant change in noise level makes the user to perceive the noise. For example, when the air conditioner is halted at a reserved time in a sleep mode, the certain change in noise level may unpleasantly awake the user from his/her sleep.

DISCLOSURE OF INVENTION

Solution to Problem

According to an aspect of an embodiment of the present disclosure, provided is a method of controlling an air conditioner. A method of controlling an air conditioner includes receiving an off-control signal to terminate air conditioning operation of the air conditioner, determining whether the off-control signal to terminate the air conditioning operation is for immediately terminating a fan operation, based on determining that the off-control signal is for immediately terminating the fan operation, stopping a fan of the air conditioner by using a normal termination control, based on determining that the off-control signal is not for immediately terminating the fan operation, determining whether a fan operation termination condition is satisfied, and based on the fan operation termination condition being satisfied, stopping the fan of the air conditioner by using noise prevention control at a rate lower than a revolution per minute (rpm) reduction rate of the fan stopping by using the normal termination control.

According to an aspect of an embodiment of the present disclosure, provided also is an air conditioner. The air conditioner includes a fan. The air conditioner also includes a fan operation module for operating the fan. The air conditioner also includes an input interface. The air conditioner also includes a communication module. The air conditioner also includes a memory to store at least one instruction. The air conditioner also includes at least one processor. The at least one processor is configured to execute the at least one instruction to receive an off-control signal to terminate air conditioning operation through the communication module or the input interface, determine whether the off-control signal to terminate the air conditioning operation is for immediately terminating fan operation, based on determining that the off-control signal is for immediately terminating the fan operation, control the fan operation module to stop the fan by using normal termination control, based on determining that the off-control signal is not for immediately terminating the fan operation, determine whether a fan operation termination condition is satisfied, and based on the fan operation termination condition being satisfied, control the fan operation module to stop the fan by using noise prevention control at a rate lower than a revolution per minute (rpm) reduction rate of the fan stopping by using the normal termination control.

According to an embodiment of the present disclosure, provided is a computer-readable recording medium having recorded thereon a program to cause a computer to perform a method of controlling an air conditioner.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 illustrates operation of an air conditioner, according to an embodiment of the present disclosure.

FIG. 2 is a block diagram illustrating a configuration of an air conditioner, according to an embodiment of the present disclosure.

FIG. 3 is a flowchart illustrating a method of controlling an air conditioner, according to an embodiment of the present disclosure.

FIG. 4 illustrates operation of a processor and a fan operation module, according to an embodiment of the present disclosure.

FIG. 5 illustrates a graph of fan rpm changes according to normal termination control, according to an embodiment of the present disclosure.

FIG. 6 illustrates a graph of fan rpm changes according to noise prevention control, according to an embodiment of the present disclosure.

FIG. 7 illustrates a method of controlling an air conditioner, according to an embodiment of the present disclosure.

FIG. 8 illustrates a graph of fan rpm changes in a case of terminating rotation of a fan in a second mode in a noise prevention mode, according to an embodiment of the present disclosure.

FIG. 9 illustrates an operation of terminating fan rotation in a second mode, according to an embodiment of the present disclosure.

FIG. 10 illustrates a graph of fan rpm changes in a case of terminating rotation of a fan in a second mode in a noise prevention mode, according to an embodiment of the present disclosure.

FIG. 11 is a flowchart illustrating a procedure for controlling a fan termination operation in a case that an automatic drying function is set, according to an embodiment of the present disclosure.

FIG. 12 illustrates an operation of terminating a fan in a windless mode, according to an embodiment of the present disclosure.

FIG. 13 illustrates a cooking appliance, a user device and a server, according to an embodiment of the present disclosure.

FIG. 14 illustrates an operation of providing information indicating that noise prevention mode is being performed, according to an embodiment of the present disclosure.

FIG. 15 illustrates an operation of immediately terminating operation of an air conditioner during termination in a second mode, according to an embodiment of the present disclosure.

FIG. 16 illustrates a configuration of an air conditioner, according to an embodiment of the present disclosure.

MODE FOR THE INVENTION

It is understood that various embodiments of the present specification and associated terms are not intended to limit technical features herein to particular embodiments, but encompass various changes, equivalents, or substitutions.

Like reference numerals may be used for like or related elements throughout the drawings.

The singular form of a noun corresponding to an item may include one or more items unless the context states otherwise.

Throughout the specification, “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 each include any one or all the possible combinations of A, B and C.

The expression “and/or” is interpreted to include a combination or any of associated elements.

Terms like “first”, “second”, etc., may be simply used to distinguish an element from another, without limiting the elements in a certain sense (e.g., in terms of importance or order).

When an element is mentioned as being “coupled” or “connected” to another element with or without an adverb “functionally” or “operatively”, it means that the element may be connected to the other element directly (e.g., wiredly), wirelessly, or through a third element.

It will be further understood that the terms “comprise” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, parts or combinations thereof, but do not preclude the possible presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

When an element is mentioned as being “connected to”, “coupled to”, “supported on” or “contacting” another element, it includes not only a case that the elements are directly connected to, coupled to, supported on or contact each other but also a case that the elements are connected to, coupled to, supported on or contact each other through a third element.

Throughout the specification, when an element is mentioned as being located “on” another element, it implies not only that the element is abut on the other element but also that a third element exists between the two elements.

An air conditioner according to various embodiments is a device for performing functions such as air purification, ventilation, humidity control, cooling or heating in an air conditioning space (hereinafter, referred to as a “room”), and refers to a device equipped with at least one of the functions.

In an embodiment, the air conditioner may include a heat pump device for performing the cooling function or the heating function. The heat pump device may include a refrigeration cycle in which a refrigerant is circulated along a compressor, a first heat exchanger, an expansion device and a second heat exchanger. All the components of the heat pump device may be built into a housing that forms the exterior of the air conditioner, and window fit air conditioners or portable air conditioners correspond to such an air conditioner. On the other hand, the components of the heat pump device may be distributed into multiple housings that form an air conditioner, which includes a wall-mounted air conditioner, a standing air conditioner, a system air conditioner, or the like.

The air conditioner including multiple housings may include at least one outdoor unit to be installed outdoors and at least one indoor unit to be installed indoors. For example, the air conditioner may be arranged such that one outdoor unit is connected to one indoor unit through a refrigerant pipe. For example, the air conditioner may be arranged such that one outdoor unit is connected to two or more indoor units through refrigerant pipes. For example, the air conditioner may be arranged such that two or more outdoor units are connected to two or more indoor units through multiple refrigerant pipes.

The outdoor unit may be electrically connected to the indoor unit. For example, information (or commands) for controlling the air conditioner may be input through an input interface arranged on the outdoor unit or the indoor unit, and in response to the user input, the outdoor unit and the indoor unit may be simultaneously or sequentially operated.

The air conditioner may include an outdoor heat exchanger arranged in the outdoor unit, an indoor heat exchanger arranged in the indoor unit, and a refrigerant pipe connecting the outdoor heat exchanger to the indoor heat exchanger.

The outdoor heat exchanger may perform heat exchange between the refrigerant and outdoor air by using a phase change of the refrigerant (e.g., evaporation or condensation). For example, the refrigerant may emit heat into the outdoor air while the refrigerant is being condensed in the outdoor heat exchanger, and the refrigerant may absorb heat from the outdoor air while the refrigerant flowing to the outdoor heat exchanger is being evaporated.

The indoor unit is arranged indoors. For example, the indoor unit may be classified into a ceiling-mounted indoor unit, a standing indoor unit, a wall-mounted indoor unit, or the like according to installation methods. For example, the ceiling-mounted indoor unit may be divided into a 4-way indoor unit, a 1-way indoor unit, a duct-type indoor unit, etc., according to air discharging methods.

Likewise, the indoor heat exchanger may perform heat exchange between the refrigerant and indoor air by using a phase change of the refrigerant (e.g., evaporation or condensation). For example, the refrigerant may absorb heat from the indoor air while being evaporated in the indoor unit, and the indoor air cooled while going through the cooled indoor heat exchanger may be blown to cool the room. Furthermore, the refrigerant may emit heat into the indoor air while being condensed in the indoor heat exchanger, and the indoor air heated while going through the hot indoor heat exchanger may be blown to heat the room.

That is, the air conditioner performs a cooling or heating function through a phase change process of the refrigerant that circulates the outdoor heat exchanger and the indoor heat exchanger, and for the circulation of the refrigerant, the air conditioner may include a compressor for compressing the refrigerant. The compressor may suck in refrigerant gas through a suction module and compress the refrigerant gas. The compressor may discharge high-temperature and high-pressure refrigerant gas through a discharger. The compressor may be arranged in the outdoor unit.

The refrigerant may circulate along the compressor, the outdoor heat exchanger, the expansion device and indoor heat exchanger in sequence through the refrigerant pipe, or circulate along the compressor, the indoor heat exchanger, the expansion device and the outdoor heat exchanger in sequence.

For example, the air conditioner may be configured so that the refrigerant is circulated between one outdoor unit and one indoor unit through the refrigerant pipe when the one outdoor unit is directly connected to the one indoor unit through the refrigerant pipe.

For example, when the air conditioner may have one outdoor unit connected to two or more indoor units through refrigerant pipes, the refrigerant may flow from the outdoor unit to the multiple indoor units through the refrigerant pipes branching from the outdoor unit. Refrigerants discharged from the multiple indoor units join and circulate to the outdoor unit. For example, the multiple indoor units may be connected to the one outdoor unit in parallel through the respective refrigerant pipes.

The multiple indoor units may each operate separately according to an operation mode set by the user. For example, some of the multiple indoor units may operate in a cooling mode while the others may operate in a heating mode. In this case, the refrigerant may selectively flow in a high-pressure or low-pressure state into each indoor unit along a designated circulation path through a flow path switching valve, which will be described later, and may be discharged and circulated into the outdoor unit.

For example, when the air conditioner has two or more outdoor units connected to two or more indoor units through multiple refrigerant pipes, refrigerants discharged from the multiple outdoor units may join and flow through one refrigerant pipe, may be divided again at a certain point and may flow into the multiple indoor units.

The multiple outdoor units may all be operated or at least some of them may not be operated depending on the operation load from an amount of operation of the multiple indoor units. In this case, the refrigerant may flow and circulate into an outdoor unit operated selectively through the flow path switching valve. The air conditioner may include an expansion device to reduce pressure of the refrigerant brought into the heat exchanger. For example, the expansion device may be arranged in the indoor unit or in the outdoor unit, or may be arranged in both of them.

The expansion device may lower the temperature and pressure of the refrigerant by using, for example, the throttling effect. The expansion device may include an orifice to reduce the cross-sectional area of the flow path. The refrigerant that has passed the orifice may have reduced temperature and pressure.

The expansion device may be implemented as an electronic expansion valve capable of controlling e.g., the opening ratio (a ratio of the cross-sectional area of the flow path of the valve in a partially open state to the cross-sectional area of the flow path of the valve in a fully open state). Depending on the opening ratio of the electronic expansion valve, the amount of refrigerant to pass the expansion device may be controlled.

The air conditioner may further include a flow path switching valve arranged in a refrigerant circulation flow path. The flow path switching valve may include, for example, a 4-way valve. The flow path switching valve may determine a circulation path of the refrigerant depending on the operation mode (e.g., cooling operation or heating operation) of the indoor unit. The flow path switching valve may be connected to a discharger of the compressor.

The air conditioner may include an accumulator. The accumulator may be connected to a suction module of the compressor. A low-temperature and low-pressure refrigerator evaporated from the indoor heat exchanger or the outdoor heat exchanger may flow into the accumulator.

When a refrigerant which is a mixture of a refrigerant liquid and a refrigerant gas flows into the accumulator, the accumulator may separate the refrigerant liquid from the refrigerant gas and provide the refrigerant gas from which the refrigerant liquid is separated to the compressor.

An outdoor fan may be arranged around the outdoor heat exchanger. The outdoor fan may blow outside air to the outdoor heat exchanger to promote heat exchange between the refrigerant and the outside air.

The outdoor unit of the air conditioner may include at least one sensor. For example, the sensor of the outdoor unit may be provided as an environmental sensor. The sensor of the outdoor unit may be arranged at a random position on the inside or outside of the outdoor unit. For example, the sensor of the outdoor unit may include, for example, a temperature sensor for detecting air temperature around the outdoor unit, a humidity sensor for detecting humidity around the outdoor unit, a refrigerant temperature sensor for detecting refrigerant temperature of a refrigerant pipe that passes through the outdoor unit, or a refrigerant pressure sensor for detecting refrigerant pressure of the refrigerant pipe that passes through the outdoor unit.

The outdoor unit of the air conditioner may include an outdoor unit communicator. The outdoor unit communicator may be arranged to receive a control signal from a controller of the indoor unit of the air conditioner, which will be described later. The outdoor unit may control an operation of the compressor, the outdoor heat exchanger, the expansion device, the flow path switching valve, the accumulator or the outdoor fan based on a control signal received through the outdoor unit communicator. The outdoor unit may transmit a sensing value detected from the outdoor unit sensor to the controller of the indoor unit through the outdoor unit communicator.

The indoor unit of the air conditioner may include a housing, a blower for circulating air into or out of the housing, and an indoor heat exchanger for exchanging heat with the air brought into the housing.

The housing may include a suction port. Indoor air may flow into the housing through the suction port.

The indoor unit of the air conditioner may include a filter arranged to filter out debris in the air brought into the housing through the suction port.

The housing may include a discharging port. The air moving in the housing may be discharged out of the housing through the discharging port.

An air flow guide may be arranged in the housing of the indoor unit to guide the direction of the air discharged through the discharging port. For example, the air flow guide may include a blade located at the discharging port. For example, the air flow guide may include an auxiliary fan for regulating the discharge airflow. It is not limited thereto, and the air flow guide may be omitted.

The indoor heat exchanger and the blower placed in a flow path connecting the suction port to the discharging port may be arranged in the housing of the indoor unit.

The blower may include an indoor fan and a fan motor. For example, the indoor fan may include an axial fan, a siroco fan, a crossflow fan, or a centrifugal fan.

The indoor heat exchanger may be arranged between the blower and the discharging port, or arranged between the suction port and the blower. The heat exchanger may absorb heat from the air brought in through the suction port or transmit heat to the air brought in through the suction port. The indoor heat exchanger may include a heat exchange tube in which the refrigerant flows, and a heat exchange fin that is in contact with the heat exchange tube to increase the heat transfer area.

The indoor unit of the air conditioner may include a drain tray arranged underneath the indoor heat exchanger to collect condensate water produced from the indoor heat exchanger. The condensate water received in the drain tray may be drained to the outside through a drain hose. The drain tray may be arranged to support the indoor heat exchanger.

The indoor unit of the air conditioner may include an input interface. The input interface may include a random type of user input module including buttons, switches, a touch screen and/or a touch pad. The user may input setting data (e.g., a desired indoor temperature, a cooling/heating/dehumidification/air purification operation mode setting, a discharge port selection setting and/or an air volume setting) through the input interface in person.

The input interface may be connected to an external input device. For example, the input interface may be electrically connected to a wired remote controller. The wired remote controller may be installed at a certain position (e.g., a portion of a wall) in an indoor space. The user may operate the wired remote controller to input setting data for operation of the air conditioner. An electric signal corresponding to the setting data obtained through the wired remote controller may be transmitted to the input interface. Furthermore, the input interface may include an infrared sensor. The user may operate a wireless remote controller to remotely input setting data for operation of the air conditioner. The setting data input through the wireless remote controller may be transmitted as an infrared signal to the input interface.

Furthermore, the input interface may include a microphone. A voice command of the user may be obtained through the microphone. The microphone may convert the voice command of the user to an electric signal, and send the electric signal to an indoor unit controller. The indoor unit controller may control components of the air conditioner to perform a function corresponding to the voice command of the user. The setting data (e.g., a desired indoor temperature, a cooling/heating/dehumidification/air purification operation mode setting, a discharge port selection setting and/or an air volume setting) obtained through the input interface may be sent to the indoor unit controller, which will be described later. For example, the setting data obtained through the input interface may be transmitted to the outside, i.e., the outdoor unit or a server, through the indoor unit communicator, which will be described later.

The indoor unit of the air conditioner 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.

The indoor unit of the air conditioner may include an indoor unit sensor. The indoor unit sensor may be an environmental sensor arranged in a space inside or outside of the housing. For example, the indoor unit sensor may include one or more temperature sensors and/or humidity sensors arranged in a predetermined space inside or outside of the indoor unit. For example, the indoor unit sensor may include a refrigerant temperature sensor for detecting temperature of the refrigerant in the refrigerant pipe that passes through the indoor unit. For example, the indoor unit sensor may include refrigerant temperature sensors for detecting respective temperatures of an inlet, center and/or outlet of the refrigerant pipe that passes through the indoor heat exchanger.

For example, each environmental information detected by the indoor unit sensor may be sent to an indoor unit controller, which will be described later, or sent to the outside through an indoor unit communicator, which will be described later.

The indoor unit of the air conditioner may include the indoor unit communicator. The indoor unit communicator may include at least one of a short-range communication module or a long-range communication module. The indoor communicator may include at least one antenna for wirelessly communicating with another device. The outdoor unit may include the outdoor unit communicator. The outdoor unit communicator may also include at least one of a short-range communication module or a long-range communication module.

The short-range communication module may include a Bluetooth communication module, a Bluetooth low energy (BLE) communication module, a near field communication (NFC) module, a WLAN, e.g., Wi-Fi, communication module, a Zigbee communication module, an infrared data association (IrDA) communication module, a Wi-Fi direct (WFD) communication module, an ultrawideband (UWB) communication module, an Ant+ communication module, a microwave (uWave) communication module, etc., without being limited thereto.

The long-range communication module may include a communication module for performing various types of long-range communication and include a mobile communication module. The mobile communication module transmits and receives RF signals to and from at least one of a base station, an external terminal, or a server in a mobile communication network.

The indoor communicator may communicate with an external device such as a server, a mobile device, another home appliance, etc., through a nearby access point (AP). The AP may connect a local area network (LAN) connected to the air conditioner or a user device to a wide area network (WAN) connected to the server. The air conditioner or the user device may be connected to the server through the WAN. The indoor unit of the air conditioner may include the indoor unit controller for controlling the components of the indoor unit including e.g., the blower. The outdoor unit of the air conditioner may include an outdoor unit controller for controlling the components of the outdoor unit including e.g., the compressor. The indoor unit controller may communicate with the outdoor unit controller through the indoor communicator and the outdoor unit communicator. The outdoor unit communicator may transmit a control signal generated by the outdoor unit controller to the indoor unit communicator, or forward the control signal transmitted from the indoor communicator to the outdoor unit controller. That is, the outdoor unit and the indoor unit may communicate bidirectionally. The outdoor unit and the indoor unit may transmit and receive various signals generated during the operation of the air conditioner.

The outdoor unit controller may be electrically connected to the components of the outdoor unit to control operations of the respective components. For example, the outdoor unit controller may control the frequency of the compressor, and control the flow path switching valve to switch the circulation direction of the refrigerant. The outdoor unit controller may control rotation speed of the outdoor fan. Furthermore, the outdoor unit controller may generate a control signal to control the opening degree of the expansion valve. Under the control of the outdoor unit controller, the refrigerant may circulate along a refrigerant circulation circuit including the compressor, the flow path switching valve, the outdoor heat exchanger, the expansion valve and the indoor heat exchanger.

Various temperature sensors included in the outdoor unit and the indoor unit may transmit electric signals corresponding to temperature detected by each of the temperature sensors to the outdoor unit controller and/or the indoor unit controller. For example, humidity sensors included in the outdoor unit and the indoor unit may transmit electric signals corresponding to humidity detected by each of the humidity sensors to the outdoor unit controller and/or the indoor unit controller.

The indoor unit controller may obtain a user input from a user device including a mobile device through the indoor unit communicator, and obtain a user input directly through the input interface or through a remote controller. The indoor unit controller may control the components of the indoor unit that includes the blower in response to the received user input. The indoor unit controller may transmit information about the received user input to the outdoor unit controller of the outdoor unit.

The outdoor unit controller may control the components of the outdoor unit that include the compressor based on information about a user input received from the indoor unit. For example, on receiving a control signal corresponding to a user input that selects an operation mode such as cooling operation, heating operation, air-blowing operation, defrost operation or dehumidification operation from the indoor unit, the outdoor unit controller may control the components of the outdoor unit to perform an operation of the air conditioner corresponding to the selected operation mode.

The outdoor unit controller and the indoor unit controller may each include a processor and a memory. The indoor unit controller may include at least one first processor and at least one first memory, and the outdoor unit controller may include at least one second processor and at least one second memory.

The memory may memorize/store various information required for operation of the air conditioner. The memory may store instructions, an application, data and/or a program required for operation of the air conditioner. For example, the memory may store various programs for the cooling operation, heating operation, dehumidification operation and/or defrost operation of the air conditioner. The memory may include a volatile memory for temporarily storing data, such as a static random access memory (SRAM) and a dynamic RAM (DRAM). The memory may also include a non-volatile memory for storing data for a long time, such as a read-only memory (ROM), an erasable programmable ROM (EPROM), or an electrically erasable programmable ROM (EEPROM).

The processor may generate control signals for controlling operation of the air conditioner based on instructions, an application, data and/or a program stored in the memory. The processor may include logic circuits and operation circuits in hardware. The processor may process the data according to the program and/or instructions provided from the memory and generate a control signal based on the processing result. The memory and the processor may be implemented with a single control circuit or multiple circuits.

The indoor unit of the air conditioner may include an output interface. The output interface may be electrically connected to the indoor unit controller, and output information relating to operation of the air conditioner under the control of the indoor unit controller. For example, information such as an operation mode, a wind direction, wind volume, or temperature selected by the user input may be output. Furthermore, the output interface may output sensing information or an alert/error message obtained from the indoor unit sensor or the outdoor unit sensor.

The output interface may include a display and a speaker. The speaker may be an audio device for outputting various sounds. The display may display information input by the user or information to be provided for the user in various graphic elements. For example, operation information of the air conditioner may be displayed in at least one of an image or text. Furthermore, the display may include an indicator for providing certain information. The display may include a liquid crystal display (LCD) panel, a light emitting diode (LED) panel, an organic LED (OLED) panel, or a micro LED panel and/or a plurality of LEDs.

An air conditioner according to various embodiments will now be described in detail in connection with the accompanying drawings.

FIG. 1 illustrates operation of an air conditioner, according to an embodiment of the present disclosure.

An air conditioner 100 according to an embodiment of the present disclosure controls rpm of a fan 110 during terminating operation to prevent noise. The air conditioner 100 includes an indoor unit and an outdoor unit. The fan 110 may correspond to a fan in the indoor unit or a fan in the outdoor unit. Although an embodiment of the present disclosure is focused on controlling the fan in the indoor unit, the noise prevention control is equally applied to the fan in the outdoor unit.

During operation, the air conditioner 100 may receive an off-control signal that requests termination of the operation. On receiving the off-control signal, the air conditioner 100 terminates air conditioning operation such as cooling or heating. The off-control signal may correspond to a first off-control signal or a second off-control signal. The first off-control signal is an off-control signal to immediately terminate fan operation. The second off-control signal is an off-control signal to terminate fan operation after a certain period of time. The air conditioner 100 immediately terminates rotation of the fan 110 in response to the first off-control signal. Furthermore, the air conditioner 100 terminates rotation of the fan 110 after the certain period of time in response to the second off-control signal.

Based on the off-control signal, the air conditioner 100 is switched from a rotation state 120 to a stopped state of the fan 110 while reducing rpm of the fan 110. With the change in rpm of the fan 110, the user perceives a change in noise of the fan 110 and recognizes the noise. In the case of the first off-control signal to immediately terminate rotation of the fan 110 based on the off-control signal, rotation of the fan 110 is stopped as soon as the user inputs the off-control signal, so the discomfort of the user is not that big because, even with a big change in nose level due to the termination of the fan 110, the noise is likely to be expected by the user. However, in the case of the second off-control signal, the fan 110 is stopped with a time difference after the user inputs the off-control signal. Hence, when the fan 110 is actually changed into the stopped state 122, it is more likely that the user is unable to expect the termination of the fan 110. This may make the user recognize the noise due to the unexpected change in noise level and feel discomfort due to the noise.

According to an embodiment of the present disclosure, in operation 132, when the second off-control signal is input to stop the fan 110 with a time difference after the off-control signal is input, the rpm change rate of the fan 110 is controlled through noise prevention control. In an embodiment of the present disclosure, by reducing the rpm change rate of the fan 110 according to the noise prevention control, the noise level change rate is reduced, which prevents the user from feeling discomfort from otherwise a sharp change of noise level.

In an embodiment of the present disclosure, in a case that the first off-control signal is input to stop the fan 110 as soon as the off-control signal is input, rotation of the fan 110 is immediately stopped by normal termination control in operation 130. Termination of the fan 10 according to the first off-control signal gives the user less discomfort from a noise change even when there is a sharp change of noise level, because the user recognizes and expects the termination of the fan 110. In an embodiment of the present disclosure, when the user sets in advance to perform the noise prevention control in terminating operation of the air conditioner, it is possible to perform the noise prevention control even for the first off-control signal.

FIG. 2 is a block diagram illustrating a configuration of an air conditioner, according to an embodiment of the present disclosure.

In an embodiment of the present disclosure, the air conditioner 100 includes the fan 110, a fan operation module 218, a processor 210, an input interface 216, a communication module 212 and a memory 214. The block diagram of the air conditioner 100 of FIG. 2 may correspond to a block diagram of the indoor unit.

The air conditioner 100 may be implemented in various installation types. For example, the air conditioner 100 may be implemented in a standing type, a wall-mounted type, a system air conditioner type that is buried in the ceiling, or a home multi-air conditioner type. The air conditioner 100 may be equipped with a heat exchanger to perform heat exchange between the refrigerant and indoor air by using a phase change (e.g., evaporation or condensation) of the refrigerant of the heat exchanger. For example, the refrigerant may absorb heat from the indoor air while the refrigerant is expanding, so that the indoor space may be cooled. The refrigerant may release heat to the indoor air while the refrigerant is being compressed, so that the indoor space may be heated.

The fan 110 is arranged around the heat exchanger. During rotation, the fan 110 blows air cooled or heated from the heat exchanger of the air conditioner 100. Due to an air flow produced by the fan 110, the air cooled or heated by the heat exchanger is discharged into an air conditioning space.

The fan operation module 218 drives the fan 110. The fan operation module 218 rotates or stops the fan 110. The fan operation module 218 rotates the fan 110 by delivering torque to the rotational axis of the fan 110. The fan operation module 218 may include a fan motor for rotating the fan 110. The fan operation module 218 applies a driving current to the fan motor to rotate the fan motor, and with the rotation of the fan motor, torque is applied to the fan 110.

The fan operation module 218 stops the fan 110 by blocking the torque applied to the fan 110 or controlling the torque of the fan 110. The fan operation module 218 may also control rpm of the fan 110 by controlling the torque applied to the fan 110. The fan operation module 218 may control the rpm of the fan 110 to rotate or stop the fan 110. Furthermore, the fan operation module 218 may control the rpm of the fan 110 to control wind-blowing intensity of the fan 110.

The fan operation module 218 generates a driving current to be applied to the fan motor according to a control signal input from the processor 210. The fan operation module 218 generates the driving current by controlling the magnitude and phase of the driving current according to a control signal.

The processor 210 controls general operation of the air conditioner 100. The processor 210 may be implemented with one or more processors. The processor 210 may execute instructions or commands stored in the memory 214 to perform a certain operation. Furthermore, the processor 210 controls operations of the components included in the air conditioner 100. The processor 210 may include a central processing unit (CPU), a microprocessor, etc.

The input interface 216 receives an input from the user. The input interface 216 may include a key, a touch screen, a touch pad, a touch sensor, etc. The input interface 216 receives the user input and forwards the user input to the processor 210. The input interface 216 may receive a power-on or -off signal, a temperature setting signal, an operation mode selection signal, a wind-blowing intensity selection signal, a bedtime reservation signal, a reserved operation setting signal, a wind-direction setting signal, etc.

The input interface 216 may receive an off-control signal that requests power-off of the air conditioner 100.

The communication module 212 may communicate with at least one external device wiredly or wirelessly. In an embodiment of the present disclosure, the communication module 212 communicates with a remote controller wirelessly. The communication module 212 may receive a power-on or -off signal, a temperature setting signal, an operation mode selection signal, a wind-blowing intensity selection signal, a bedtime reservation signal, a reserved operation setting signal, a wind-direction setting signal, etc., from the remote controller. The communication module 212 may transmit status information of the air conditioner 100 to the remote controller to synchronize the status information of the air conditioner 100 with the remote controller.

The communication module 212 may receive the off-control signal that requests power-off of the air conditioner 100 from the remote controller.

Furthermore, in an embodiment of the present disclosure, the communication module 212 may communicate with the outdoor unit. For example, the communication module 212 may use RS-485 serial communication to communicate with the outdoor unit.

Furthermore, in an embodiment of the present disclosure, the communication module 212 may communicate with a server over a network. The communication module 212 may access the network through an access point (AP) device and communicate with a server. The communication module 212 may receive the off-control signal from the server. Furthermore, the communication module 212 may receive a power-on or -off signal, a temperature setting signal, an operation mode selection signal, a wind-blowing intensity selection signal, a bedtime reservation signal, a reserved operation setting signal, a wind-direction setting signal, etc., from the server. The communication module 212 may transmit status information of the air conditioner 100 to the server to synchronize the status information of the air conditioner 100 with the server. Moreover, the communication module 212 may receive, from the server, an operation mode or setting information of the air conditioner 100 that is set by using e.g., a user terminal.

The communication module 212 may include a wireless communication module (e.g., a cellular communication module, a short-range wireless communication module or a global navigation satellite system (GNSS) communication module) or a wired communication module (e.g., a local area network (LAN) communication module or a power-line communication module). Furthermore, the communication module 212 may perform short-range communication, and may use, for example, Bluetooth, Bluetooth low energy (BLE), near field communication (NFC), WLAN (Wi-Fi), Zigbee, infrared data association (IrDA) communication, Wi-Fi direcet (WFD), ultrawideband (UWB), Ant+ communication, etc. Moreover, for example, the communication module 212 may perform long-range communication to communicate with an external device through, for example, a legacy cellular network, a fifth generation (5G) network, a next generation communication network, the Internet, or a computer network (e.g., LAN or WAN).

In addition, for example, the communication module 212 may use mobile communication and transmit or receive a wireless signal to or from at least one of a base station, an external terminal or a server over a mobile communication network.

In an embodiment, the communication module 212 is connected to a home AP through Wi-Fi communication. The communication module 212 may communicate with an external device through a connection repeater.

The memory 214 stores various information, data, instructions, programs, etc., required for operation of the air conditioner 100. The memory 214 may include at least one or a combination of volatile memories or non-volatile memories. The memory 214 may include at least one type of storage medium including a flash memory, a hard disk, a multimedia card micro type memory, a card type memory (e.g., SD or XD memory), a RAM, an, SRAM, a ROM, an EEPROM, a PROM, a magnetic memory, a magnetic disk, and an optical disk. The memory 214 may correspond to a web storage or a cloud server that performs a storage function on the Internet.

The processor 210 detects an off-control signal from a control signal received through the input interface 216 or the communication module 212. On receiving the power-off signal, the processor 210 identifies, recognizes or determines that the off-control signal is received. Also, on receiving the termination reservation signal, the processor 210 identifies, recognizes or determines that the off-control signal is received. The termination reservation signal may include, for example, a reservation setting signal that reserves power-off after a certain period of time or at a certain time, or a sleep mode setting signal that reserves power-off after operation in the sleep mode.

On receiving the power-off signal through the input interface 216 or the communication module 212, the processor 210 immediately terminates the air conditioning operation of the air conditioner 100. The power-off signal corresponds to the off-control signal. On receiving the power-off signal, the processor 210 terminates the rotation of the fan 110 in a first mode for stopping the fan 110 by blocking the driving current applied to the fan 110 from the fan operation module 218 or by setting the driving current to ‘0’ (zero).

In an embodiment of the present disclosure, on receiving the power-off signal, the processor 210 determines whether an additional function is set before power-off. On receiving the power-off signal, the processor 210 determines whether an automatic drying function is set. When the automatic drying function is set, the processor 210 terminates operation of the fan 110 after a standby time for performing automatic drying. After completion of the automatic drying, the processor 210 stops the fan 110 in a second mode for performing noise prevention control.

On receiving a termination reservation signal for the air conditioner 100 through the input interface 216 or the communication module 212, the processor 210 terminates the operation of the fan 110 after a certain termination reservation time is reached. When the termination reservation time is reached, the processor 210 stops the fan 110 in the second mode for performing the noise prevention control.

The processor 210 stops the fan 110 by performing the nose prevention control in the second mode. In the second mode, the processor 210 reduces the rpm of the fan 110 at a rate lower than in the first mode instead of immediately stopping the fan 110. The processor 210 controls a fan driving current applied to the fan motor from the fan operation module 218 to control a reduction rate of the rpm of the fan 110. The processor 210 may control the rpm of the fan 110 by controlling the fan driving current. In the second mode, the processor 210 blocks the driving current applied to the fan motor from the fan operation module 218 at a certain rate instead of immediately. The processor 210 may reduce the rpm that is equal to or higher than certain rpm at a certain rate, and when the rpm reaches a certain value, block the fan driving current under the normal termination control.

In an embodiment of the present disclosure, the processor 210 may control the fan rpm according to a PID control method. The processor 210 controls the fan rpm to be target rpm by receiving feedback on a fan rpm value from the fan operation module 218. The fan operation module 218 controls rpm of the fan 110 according to PWM control. The processor 218 generates a fan rpm control signal for the PWM control of the fan operation module 218. The processor 218 outputs the fan rpm control signal to the fan operation module 218. The processor 210 performs noise prevention control by generating a fan rpm control signal to reduce the fan rpm at a certain rate in the second mode.

FIG. 3 is a flowchart illustrating a method of controlling an air conditioner, according to an embodiment of the present disclosure.

The method of controlling an air conditioner according to an embodiment of the present disclosure may be performed by the air conditioner 100 according to an embodiment of the present disclosure.

In operation S302, the air conditioner 100 receives an off-control signal. When receiving a power-off signal or a termination reservation signal, the air conditioner 100 may recognize that the off-control signal is input. The air conditioner 100 may receive the off-control signal through the input interface 216 or receive the off-control signal through the communication module 212. The air conditioner 100 may receive the off-control signal through the communication module 212 from a remote controller, a server or a user terminal.

Subsequently, in operation S304, the air conditioner 100 determines whether the off-control signal is to immediately stop the operation of the fan 110 of the air conditioner 100. When the power-off signal is received, the air conditioner 100 determines that the signal is to immediately stop the operation of the fan 110.

In an embodiment of the present disclosure, on receiving the power-off signal, the air conditioner 100 determines whether an additional function is set before power-off. When the power-off signal is received and the additional function is set before power-off, the air conditioner 100 determines that the fan operation is not to be immediately stopped.

When the termination reservation signal is received, the air conditioner 100 determines that the fan operation is not to be immediately stopped. The termination reservation signal may include a reservation setting signal or a sleep mode setting signal.

When determining that the fan operation is to be immediately stopped in response to the off-control signal, the air conditioner 100 stops the rotation of the fan 110 in the first mode according to normal termination control in operation S306. The air conditioner 100 stops the rotation of the fan 110 in the first mode by blocking the driving current to the fan motor that applies torque to the fan 110. When the driving current to the fan motor is blocked, the fan 110 is stopped with rpm decreasing due to inertia.

When determining that the fan operation is not to be immediately stopped in response to the off-control signal, the air conditioner 100 operates the fan 110 until a certain condition is met in operation S308. For example, when the off-control signal corresponding to the reservation setting signal is received, the air conditioner 100 operates the fan 110 until a set power-off time is reached. Furthermore, for example, when the off-control signal corresponding to the sleep mode setting signal is received, the air conditioner 100 operates the fan 110 until a set power-off time is reached.

When the fan operation termination condition is met, the air conditioner 100 stops the rotation of the fan 110 in the second mode according to the noise prevention control in operation S310. The air conditioner 100 reduces the rpm at a certain rate in the second mode. The air conditioner 100 minimizes the discomfort felt by the user who feels a change in noise level by reducing the rpm at a certain rate and thus reducing the change rate of the noise level.

FIG. 4 illustrates operation of a processor and a fan operation module, according to an embodiment of the present disclosure.

In an embodiment of the present disclosure, on receiving the off-control signal, the processor 210 and the fan operation module 218 sets a control mode for stopping the fan 110 and controls the stopping operation of the fan 110. FIG. 4 is focused on the fan termination control operation of the processor 210 and the fan operation module 218. Blocks illustrated in the processor 210 may correspond to software blocks to perform a certain process. The software blocks may be differently configured depending on the algorithm or control method, and the software blocks shown in FIG. 4 correspond to an embodiment of the present disclosure.

When receiving or identifying the off-control signal, the processor 210 sets a control mode for termination operation based on the off-control signal. The control mode includes the first mode using normal termination control and the second mode using noise prevention control. A control mode setting module 410 sets the control mode to the first mode or the second mode for the termination operation, based on the off-control signal and a mode set for the air conditioner 100 according to the aforementioned method set with reference to FIGS. 2 and 3.

When the first mode is set, the control mode setting module 410 generates a termination control signal to stop the fan 110 and outputs the termination control signal to the fan operation module 218. When the first mode is set, the control mode setting module 410 generates a termination control signal to control the driving current applied to the fan motor 440 to be blocked and outputs the termination control signal to the fan operation module 218.

When the second mode is set, the control mode setting module 410 generates a termination control signal to request controlling the fan rpm in the second mode and outputs the termination control signal to a reduction rate setting module 420.

The reduction rate setting module 420 controls the reduction rate of the fan rpm in the second mode based on the termination control signal. The reduction rate setting module 420 receives feedback on a current fan rpm value from the fan operation module 218, and based on the current fan rpm value, controls the rpm reduction rate. In an embodiment of the present disclosure, the reduction rate setting module 420 reduces the fan rpm at a low rate in a section having high fan rpm as compared to a section having low fan rpm.

The reduction rate setting module 420 determines a rpm reduction rate based on the fan rpm, and generates an rpm setting value determined based on the rpm reduction rate and outputs the rpm setting value to a PID controller 430. The rpm setting value is set as a target value or reference value of the PID controller 430.

The PID controller 430 receives the rpm setting value from the reduction rate setting module 420. The PID controller 430 also receives the fan rpm value from the fan operation module 218. The PID controller 430 generates a fan rpm control signal to control the fan rpm based on the rpm setting value and the fan rpm value. Based on the fan rpm value fed back from the fan operation module 218, the PID controller 430 adjusts the fan rpm value to the rpm setting value. When the fan rpm value is larger than the rpm setting value, the PID controller 430 reduces the fan rpm, and when the fan rpm value is smaller than the rpm setting value, the PID controller 430 increases the fan rpm. The PID controller 430 maintains the fan rpm when the fan rpm value is within an error range from the rpm setting value.

In an embodiment of the present disclosure, the fan operation module 218 controls the fan rpm according to pulse width modulation (PWM) control. The fan operation module 218 controls the magnitude of the torque delivered to the fan 110 from the fan motor 440 by modulating pulse width of the waveforms of the driving current applied to the fan motor 440. The PID controller 430 controls the fan rpm by controlling a duty ratio of the PWM control of the fan operation module 218. The PID controller 430 may reduce the duty ratio to decrease the fan rpm and increase the duty ratio to increase the fan rpm. The PID controller 430 generates a fan rpm control signal to set a duty ratio of the PWM control, and outputs the fan rpm control signal to the fan operation module 218. The fan operation module 218 adjusts the duty ratio of the PWM control based on the fan rpm control signal. The fan operation module 218 applies a driving current generated by the PWM control to the fan motor 440.

FIG. 5 illustrates a graph of fan rpm changes according to normal termination control, according to an embodiment of the present disclosure.

In an embodiment of the present disclosure, the air conditioner 100 terminates the rotation of the fan 110 by using normal termination control in the first mode. When the off-control signal to immediately terminate the operation of the fan 110 is input, the air conditioner 100 blocks the driving current applied to the fan motor 440. As the driving current applied to the fan motor 440 is blocked, the fan 110 is stopped and the fan rpm decreases at a high rate. For example, when the fan 110 is stopped according to the normal termination control while the fan 110 is rotating in a high noise region of rpm 1000 or higher, the rpm of the fan 110 decreases from 1000 or more to 0 within a few seconds. This causes a noticeable change in nose level within a few seconds due to the change in fan rpm within the few seconds from the high noise region to a point where the noise disappears. The user may perceive the noise level change significantly.

FIG. 6 illustrates a graph of fan rpm changes according to noise prevention control, according to an embodiment of the present disclosure.

In an embodiment of the present disclosure, the air conditioner 100 stops the rotation of the fan 110 by using noise prevention control in the second mode. When an off-control signal to stop operation of the fan 110 with a certain time difference is input, the air conditioner 100 maintains the operation of the fan 110 in section T602 until the fan operation termination condition is satisfied. The air conditioner 100 reduces the rpm of the fan 110 at a certain rate in section T604 when the fan operation termination condition is satisfied. In section T604, the reduction rate of the rpm of the fan 110 is lower than the rpm reduction rate of the normal termination control.

In an embodiment of the present disclosure, in the second mode, the air conditioner 100 stops controlling the fan rpm for a certain fan rpm value or less, and uses the normal termination control to terminate the rotation of the fan 110. For example, as shown in FIG. 6, the air conditioner 100 performs fan rpm control in section T604, and when the fan rpm reaches 500, terminates the rotation of the fan 110 by blocking the driving current applied to the fan motor 440. Accordingly, in section T606, the air conditioner 100 terminates the rotation of the fan 110 according to the normal termination control method.

FIG. 7 illustrates a method of controlling an air conditioner, according to an embodiment of the present disclosure.

In an embodiment of the present disclosure, when receiving the off-control signal and determining that the fan operation is to be immediately terminated, the air conditioner 100 may further determine whether a noise prevention mode is set for the air conditioner 100. Even in a case of immediately terminating the fan operation, when a certain function is set, the air conditioner 100 may terminate the rotation of the fan 110 by using the noise prevention control in the second mode.

FIG. 7 is focused on a difference from what is described in FIG. 3 in describing the operation of the air conditioner 100.

In operation S302, the air conditioner 100 receives an off-control signal. When receiving a power-off signal or a termination reservation signal, the air conditioner 100 may recognize that the off-control signal is input.

Subsequently, in operation S304, the air conditioner 100 determines whether the off-control signal is to immediately stop the operation of the fan 110 of the air conditioner 100. When the power-off signal is received, the air conditioner 100 determines that the signal is to immediately stop the operation of the fan 110.

In an embodiment of the present disclosure, on receiving the power-off signal, the air conditioner 100 determines whether an additional function is set before power-off. When the power-off signal is received and the additional function is set before power-off, the air conditioner 100 determines that the fan operation is not to be immediately terminated.

When the termination reservation signal is received, the air conditioner 100 determines that the fan operation is not to be immediately terminated. The termination reservation signal may include a reservation setting signal or a sleep mode setting signal.

When determining that the fan operation is to be immediately stopped in response to the off-control signal, the air conditioner 100 determines whether the noise prevention mode is set in operation S702.

In an embodiment of the present disclosure, the noise prevention mode is one preset by the user. For example, the user may set the noise prevention mode in advance to prevent noise occurrences by always performing noise prevention control in terminating the operation of the air conditioner 100. In an embodiment of the present disclosure, the user may set the noise prevention mode in advance by using the input interface 216 of the air conditioner 100. Furthermore, in an embodiment of the present disclosure, the user may set the noise prevention mode in advance through a remote controller. In an embodiment of the present disclosure, the user may set the noise prevention mode in advance through an application of a user terminal to control the air conditioner 100. When the noise prevention mode is set through the application of the user terminal, information indicating that the noise prevention mode is set is shared, and the information indicating that the noise prevention mode is set is transmitted to the air conditioner 100. The air conditioner 100 receives the information indicating that the noise prevention mode is set through the communication module 212, and sets the noise prevention mode.

In an embodiment of the present disclosure, when the current time belongs to a preset noise prevention time zone, the air conditioner 100 determines that it corresponds to the noise prevention mode. The user may set the noise prevention time zone in advance. For example, the user may set a night time zone as the noise prevention time zone. Furthermore, for example, the user may set a particular time zone such as working hours, class hours, etc., as the noise prevention time zone. When the current time belongs to the noise prevention time zone, the air conditioner 100 may terminate the fan operation by always using the noise prevention control in the second mode in response to the off-control signal. The noise prevention time zone may be set according to a control signal received from the input interface 216 of the air conditioner 100 or set according to a control signal received from a remote controller. Furthermore, the noise prevention time zone may be set by the application of the user terminal, and the air conditioner 100 may receive, from the server, information indicating that the noise prevention time zone is set.

When it is determined that the noise prevention mode is set in operation S702, the air conditioner 100 stops the fan 110 by using the noise prevention control in the second mode in operation S310.

When it is not determined that the noise prevention mode is set in operation S702, the air conditioner 100 stops the fan 110 by using the normal termination control in the first mode in operation S306.

When determining that the fan operation is not to be immediately stopped in response to the off-control signal, the air conditioner 100 operates the fan 110 until a certain condition is met in operation S308.

When the fan operation termination condition is met, the air conditioner 100 stops the rotation of the fan 110 in the second mode according to the noise prevention control in operation S310. The air conditioner 100 reduces the rpm at a certain rate in the second mode.

FIG. 8 illustrates a graph of fan rpm changes in a case of terminating rotation of a fan in a second mode in a noise prevention mode, according to an embodiment of the present disclosure.

FIG. 8 may correspond to a case of stopping the rotation of the fan 110 in the second mode in operation S310 after the noise prevention mode is determined as being set in operation S702 of FIG. 7.

In an embodiment of the present disclosure, when the noise prevention mode is set, the air conditioner 100 receives the off-control signal, and stops the rotation of the fan 110 by using noise prevention control in the second mode. The air conditioner 100 reduces the rpm of the fan 110 at a certain rate in section T802 based on the off-control signal. In section T802, the reduction rate of the rpm of the fan 110 is lower than the rpm reduction rate according to the normal termination control. The reducing of the rpm of the fan 110 in section T802 may correspond to the reducing of the rpm of the fan 110 in section T604 of FIG. 6.

In an embodiment of the present disclosure, in the second mode, the air conditioner 100 stops controlling the fan rpm for a certain fan rpm value or less, and uses the normal termination control to terminate the rotation of the fan 110. For example, as shown in FIG. 8, the air conditioner 100 performs fan rpm control in section T802, and when the fan rpm reaches 500, terminates the rotation of the fan 110 by blocking the driving current applied to the fan motor 440. Accordingly, in section T804, the air conditioner 100 terminates the rotation of the fan 110 according to the normal termination control method.

FIG. 9 illustrates an operation of terminating fan rotation in a second mode, according to an embodiment of the present disclosure.

FIG. 10 illustrates a graph of fan rpm changes in a case of terminating rotation of a fan in a second mode in a noise prevention mode, according to an embodiment of the present disclosure.

In an embodiment of the present disclosure, the air conditioner 100 may control the fan rpm reduction rate depending on the fan rpm section in terminating the fan rotation in the second mode. The fan rpm section may include a first section, a second section and a third section. The first section is a section where the fan rpm has a value equal to or greater than a first reference value. The second section is a section where the fan rpm has a value equal to or greater than a second reference value and less than the first reference value. The third section is a section where the fan rpm has a value less than the second reference value.

In an embodiment of the present disclosure, the first reference value may correspond to rpm 1000 and the second reference value may correspond to rpm 500. Furthermore, in an embodiment of the present disclosure, the first section may correspond to a high noise region and the second section may correspond to a low noise region. In an embodiment of the present disclosure, by setting the fan rpm reduction rate in the high noise region to be lower than in the low noise region, the discomfort felt by the user who feels a noise level change in the high noise region may be reduced.

Referring to FIG. 9, an operation of stopping the fan rotation in the second mode will be described in detail.

In operation S902, the air conditioner 100 obtains an rpm value of the fan 110. The processor 210 may obtain the fan rpm value from the fan operation module 218.

Subsequently, in operation S904, the air conditioner 100 determines whether the fan rpm value belongs to the first section. The air conditioner 100 performs low-coefficient PID control in operation S906 when the fan rpm value belongs to the first section. According to the low-coefficient PID control, the fan rpm value is controlled such that the rpm reduction rate corresponds to a first rate.

When the fan rpm value does not belong to the first section in operation S904, the air conditioner 100 determines whether the fan rpm value belongs to the second section in operation S908. The air conditioner 100 performs high-coefficient PID control in operation S910 when the fan rpm value belongs to the second section. According to the high-coefficient PID control, the fan rpm value is controlled such that the rpm reduction rate corresponds to a second rate. The second rate is higher than the first rate. Both the first rate and the second rate are lower than the fan rpm reduction rate of the normal termination control.

When PID control is performed as the rpm of the fan 110 belongs to the first section or the second section, the air conditioner 100 performs low-coefficient PID control or high-coefficient PID control while monitoring the fan rpm value. Therefore, depending on the fan rpm value, operations S902, S904, S906, S908 and S910 are repeatedly performed.

When the fan rpm value does not belong to the second section in operation S908, the air conditioner 100 stops the fan 110 according to normal termination control in operation S912. When the fan rpm value does not belong to the second section in operation S908, the fan rpm value belongs to a third section. When the fan rpm value belongs to the third section, the air conditioner 100 stops the fan 110 according to normal termination control by blocking the driving current applied to the fan motor 440. When the fan rpm value belongs to the third section, the rotation of the fan has a low noise level, so the change in noise level is not high even when the rotation of the fan 110 is stopped using the normal termination control. According to an embodiment of the present disclosure, by not performing the noise prevention control for a low noise level, unnecessary control operations on the fan 110 is prevented.

FIG. 11 is a flowchart illustrating a procedure for controlling a fan termination operation in a case that an automatic drying function is set, according to an embodiment of the present disclosure.

In an embodiment of the present disclosure, an automatic drying function may be set in the air conditioner 100. The automatic drying function is a function to power off the air conditioner 100 after drying the inside of the air conditioner 100 by performing a wind-blowing operation for a certain period of time (e.g., 20 minutes) when the air conditioner 100 is to be powered off. When the automatic drying function is set, the air conditioner 100 is powered off not immediately but after a certain period of time even when the power-off signal is received. In an embodiment of the present disclosure, in a case that the automatic drying function is set, even when the power-off signal to request to power off the air conditioner 100 immediately, the air conditioner 100 may determine that the power-off signal is not an off-control signal to stop the fan operation immediately.

Referring to FIG. 11, in operation S1102, the air conditioner 100 receives a power-off control signal. The air conditioner 100 identifies the power-off control signal as an off-control signal. Operation S1102 of FIG. 11 may correspond to operation S302 of FIG. 3.

On receiving the power-off control signal, the air conditioner 100 determines whether the automatic drying function is set in operation S1104. In an embodiment of the present disclosure, the automatic drying function may be set by a control signal input through the input interface 216, set by a control signal input through a remote controller, or set by a control signal input through an application on a user terminal. In an embodiment of the present disclosure, an automatic drying time may be set automatically or set by an input from the user.

When the automatic drying function is set, the air conditioner 100 determines that the off-control signal is not for immediately stopping the fan operation in operation S1106. The air conditioner 100 performs the automatic drying function for a certain period of time in operation S1110. The air conditioner 100 performs the automatic drying function by rotating the fan 110 at certain rpm for a certain period of time.

When the automatic drying operation is completed, the air conditioner 100 stops rotation of the fan 110 by using the noise prevention control in the second mode in operation S310.

When the automatic drying function is not set, the air conditioner 100 determines that the received off-control signal is for immediately stopping the fan operation in operation S1108. Subsequently, in operation S306, the air conditioner 100 stops rotation of the fan 110 by using normal termination control in the first mode.

In an embodiment of the present disclosure, the air conditioner 100 may determine whether the automatic drying function is set even when the termination reservation signal is received. When the termination reservation signal is received and the automatic drying function is set, the air conditioner 100 performs the automatic drying operation after a reserved termination time is reached, and stops the fan 110 in the second mode. When the termination reservation signal is received and the automatic drying function is not set, the air conditioner 100 stops the fan 110 in the second mode after a reserved termination time is reached.

FIG. 12 illustrates an operation of terminating a fan in a windless mode, according to an embodiment of the present disclosure.

In an embodiment of the present disclosure, the air conditioner 100 may operate in a windless mode. The windless mode is a mode for performing an air conditioning operation at a noise level that is equal to or lower than a noise reference value. According to an embodiment of the present disclosure, the air conditioner 100 may operate at fan rpm belonging to the third section of the graph shown in FIG. 10 in the windless mode. When an off-control signal is received during operation in the windless mode, the air conditioner 100 may stop the fan 110 by not using the noise prevention control in the second mode but using the normal termination control in the first mode. When the air conditioner 100 is operating in the windless mode, the noise level of the air conditioner 100 is already low, and thus, the change in noise level is not big even when the fan 110 is stopped in the first mode. Accordingly, in an embodiment of the present disclosure, when the air conditioner 100 is operating in the windless mode, unnecessary noise prevention control may be prevented by stopping the fan 110 in the first mode.

FIG. 12 illustrates an occasion when an off-control signal is not for immediately stopping the fan operation. Operation S1202 of FIG. 12 represents determining that a fan operation termination condition is satisfied in operation S308 of FIG. 3.

When first determining that the fan operation termination condition is satisfied in operation S1202, it is determined whether the air conditioner 100 is operating in the windless mode in operation S1204. The windless mode may be set by a control signal input through the input interface 216, set by a control signal input through a remote controller, or set by a control signal input through an application on a user terminal.

When it is determined that the air conditioner 100 is operating in the windless mode, the air conditioner 100 stops the fan 110 by using the normal termination control in the first mode in operation S1206.

When it is determined that the air conditioner 100 is not operating in the windless mode, the air conditioner 100 stops the fan 110 by using the noise prevention control in the second mode in operation S1208.

FIG. 13 illustrates a cooking appliance, a user device and a server, according to an embodiment of the present disclosure.

In an embodiment of the present disclosure, an indoor unit 1330 communicates with a user device 1310 and a server 1320 through a communication module (not shown). The indoor unit 1330 may be connected to another home appliance, the user device 1310 or the server 1320 over a network NET. An outdoor unit 1340 may be connected to the indoor unit 1330 through 485 communication.

The server 1320 may manage user account information, and information of the indoor unit 1330 connected to the user account. For example, the user may access the server 1320 through the user device 1310 to create a user account. The user account may be identified by an identity (ID) and a password created by the user. The server 1320 may register the indoor unit 1330 with the user account according to a set procedure. For example, the server 1320 may connect identification information (e.g., a serial number or a media access control (MAC) address) of the indoor unit 1330 to the user account to register the indoor unit 1330.

The user device 1310 may include a communication module for communicating with the indoor unit 1330 and the server 1320, a user interface for receiving user inputs or outputting information for the user, at least one processor for controlling operations of the user device 1310, and at least one memory for storing a program for controlling the operations of the user device 1310.

The user device 1310 may be carried by the user or placed at the user's home or office. The user device 1310 may include, for example, a personal computer, a terminal, a portable telephone, a smart phone, a handheld device, a wearable device, etc., without being limited thereto.

In the memory of the user device 1310, a program for controlling the indoor unit 1330 (e.g., an application) may be stored. The user device 1310 may be sold with or without an application installed therein to control the indoor unit 1330. In a case that the user device 1310 is sold without the application installed therein for controlling the indoor unit 1330, the user may download the application from an external server that provides the application and install the application in the user device 1310.

The user may use the application installed in the user device 1310 to control the indoor unit 1330. For example, when the user executes the application installed in the user device 1310, identification information of the indoor unit 1330 connected to the same user account as the user device 1310 may appear on an application execution window. The user may perform desired control over the indoor unit 1330 through the application execution window. When the user inputs a control command for the indoor unit 1330 through the application execution window, the user device 1310 may send the control command directly to the indoor unit 1330 over a network, or send the control command to the indoor unit 1330 via the server 1320.

The application of the user device 1310 may receive various user inputs for controlling the air conditioner 100. The application provides a graphic user interface (GUI) for receiving various user inputs and receives a user input through the GUI. While communicating with the server 1320, the user device 1310 updates status information of the air conditioner 100 and provides the status information through the application. Furthermore, the user device 13010 transmits a user input received through the application to the air conditioner 100 while communicating with the server 13120.

The application may receive a power-off signal or a termination reservation signal for the air conditioner 100. The application may also receive a reservation setting signal and receive a user input to set a reserved termination time. The application may also receive a sleep mode setting signal and receive a user input to set a reserved termination time. The application may also receive a user input to set a noise prevention mode. The application may also receive a user input to set an automatic drying function. The application may also receive a user input to set the windless mode.

The network NET may include both a wired network and a wireless network. The wired network may include a cable network or a telephone network, and the wireless network may include any network that transmits or receives signals in radio waves. The wired network and the wireless network may be connected to each other.

The network NET may include a wide area network (WAN) such as the Internet, a local area network (LAN) formed around an access point (AP), and a wireless personal area network (WPAN) without going through an AP. The short-range wireless network may include bluetooth (IEEE 802.15.1), Zigbee (IEEE 802.15.4), wireless fidelity (Wi-Fi) direct, near field communication (NFC), Z-wave, etc., without being limited thereto.

The AP may connect a local area network (LAN) connected to the indoor unit 1330 and the user device 1310 to a wide area network (WAN) connected to the server 1320. The indoor unit 1330 or the user device 1310 may be connected to the server 1330 through the WAN.

The AP may use wireless communication such as Wi-Fi (IEEE 802.11) to communicate with the indoor unit 1330 and the user device 1310, and use wired communication to access the WAN.

The indoor unit 1330 may transmit information about an operation or state to the server 1320 over the network NET. For example, the indoor unit 1330 may transmit the information about the operation or state to the server 1320 through Wi-Fi (IEEE 802.11) communication. The indoor unit 1330 may also transmit information about an operation or state of the outdoor unit 1340 to the server 1320 over the network NET.

In a case that the indoor unit 1330 is not equipped with a Wi-Fi communication module, the indoor unit 1330 may transmit the information about the operation or state to the server 1320 through another home appliance having the Wi-Fi communication module. For example, when the indoor unit 1330 transmits information about an operation or state of the indoor unit 1330 to the other home appliance through WPAN (e.g., Bluetooth low energy (BLE)), the other home appliance may forward the information about the operation or state to the server 1320. Furthermore, for example, when the indoor unit 1330 is not equipped with the Wi-Fi communication module, the indoor unit 1330 may be wiredly connected to a communication AP and Wi-Fi communication and 485 communication may be performed by the communication AP.

The indoor unit 1330 may provide information about an operation or state of the indoor unit 1330 or information about an operation or state of the outdoor unit 1340 to the server 1320 according to the user's prior approval. Transmission of the information to the server 1320 may be performed by being requested from the server 1320, when a certain event occurs to the indoor unit 1330, periodically or in real time.

On receiving the information about the operation or state of the indoor unit 1330 or the information about the operation or state of the outdoor unit 1340, the server 1320 may update information relating to the air conditioner 100 that has been stored. The server 1320 may transmit the information about the operation or state of the indoor unit 1330 or the outdoor unit 1340 to the user device 1310 over the network NET.

On receiving a request from the user device 1310, the server 1320 may transmit the information about the operation or state of the indoor unit 1330 or the outdoor unit 1340 to the user device 1310. For example, when the user executes, in the user device 1310, an application connected to the server 1320, the user device 1310 may request and receive information about an operation or state of the indoor unit 1330 or the outdoor unit 1340 from the server 1320 through the application. On receiving the information about the operation or state from the indoor unit 1330, the server 1320 may forward the information about the operation or state of the indoor unit 1330 or the outdoor unit 1340 to the user device 1310 in real time. The server 1320 may forward the information about the operation or state of the indoor unit 1330 or the outdoor unit 1340 to the user device 1310 periodically. The user device 1310 may deliver the information about the operation or state of the indoor unit 1330 or the outdoor unit 1340 by displaying the information about the operation or state of the indoor unit 1330 or the outdoor unit 1340 in the application execution window.

The indoor unit 1330 may obtain various information from the server 1320, and provide the obtained information to the user. Furthermore, the indoor unit 1330 may receive, from the server 1320, a file to update pre-installed software or data related to the software, and based on the received file, update the pre-installed software or the data related to the software.

The indoor unit 1330 may operate according to a control command received from the server 1320. For example, when the indoor unit 1330 has won prior approval of the user to operate according to a control command of the server 1320 even without having a user input, the indoor unit 1330 may operate according to the control command received from the server 1320. The control command received from the server 1320 may include a control command input by the user through the user device 1320, a control command generated by the server 1320 based on a preset condition or the like, without being limited thereto.

FIG. 14 illustrates an operation of providing information indicating that noise prevention mode is being performed, according to an embodiment of the present disclosure.

In an embodiment of the present disclosure, when operating in the noise prevention mode, the air conditioner 100 may provide information indicating that termination is in progress in the noise prevention mode, through the user interface.

In an embodiment of the present disclosure, the air conditioner 100 may include an output interface 1410, and may output the information indicating that termination is in progress in the noise prevention mode, through the output interface 1410. The output interface 1410 may include, for example, a display or a speaker. In an embodiment of the present disclosure, the air conditioner 100 may display a message indicating that termination is in progress in the noise prevention mode, through the output interface 1410. Furthermore, the air conditioner 100 may output a voice message indicating that termination is in progress in the noise prevention mode, through the output interface 1410.

In an embodiment of the present disclosure, the air conditioner 100 may output information indicating that termination is in progress in the noise prevention mode, through a remote controller 1420. The remote controller 1420 may include, for example, a display or a speaker. In an embodiment of the present disclosure, the air conditioner 100 may display a message indicating that termination is in progress in the noise prevention mode, through the remote controller 1420. Furthermore, the air conditioner 100 may output a voice message indicating that termination is in progress in the noise prevention mode, through the remote controller 1420.

In an embodiment of the present disclosure, the air conditioner 100 may output information indicating that termination is in progress in the noise prevention mode, through the user device 1310. In an embodiment of the present disclosure, the air conditioner 100 may display a message indicating that termination is in progress in the noise prevention mode, through an application of the user device 1310. Furthermore, the air conditioner 100 may output a voice message indicating that termination is in progress in the noise prevention mode, through the application of the user device 1310.

FIG. 15 illustrates an operation of immediately terminating operation of an air conditioner during termination in a second mode, according to an embodiment of the present disclosure.

In an embodiment of the present disclosure, while being terminated using the noise prevention control in the second mode, the air conditioner 100 may receive a user input to request immediate termination. In this case, the air conditioner 100 may terminate the noise prevention control, and may stop the fan 110 according to the normal termination control by blocking the driving current to the fan motor.

Referring to FIG. 15, in operation S1502, the air conditioner 100 performs the noise prevention control in the second mode. Operation S1502 corresponds to the aforementioned operation of terminating the fan 110 in the second mode in operation S310 of FIG. 3.

In operation S1504, the air conditioner 100 determines whether a user input to request immediate termination of operation of the air conditioner 100 is received during termination of the fan 110 in the second mode. While performing the noise prevention control in the second mode, the air conditioner 100 may receive the power-off signal to request immediate termination of operation of the air conditioner 100. The power-off signal may be received through the input interface 216, the remote controller 1420, or an application of the user terminal 1310.

When the termination request is received, in operation S1506, the air conditioner 100 terminates the noise prevention control, changes into the first mode and stops the fan 110. The air conditioner 100 terminates the fan rpm control operation, and blocks the driving current applied to the fan motor to stop the rotation of the fan 110 in the first mode.

FIG. 16 illustrates a configuration of an air conditioner, according to an embodiment of the present disclosure.

In an embodiment of the present disclosure, an indoor unit 1620 of the air conditioner 100 communicates with a device management server 1610 and a service server 1612 through an AP 1616 and the Internet 1614.

The device management server 1610 is a server to monitor the air conditioner 100 and manage a device. The device management server 1610 collects status information of a device registered in the server. The device management server 1610 uses the collected status information to monitor each device. The device management server 1610 may also transmit a notification about a device from which an error is detected to the user terminal 1310 or the device.

The service server 1612 provides a certain function or service for the air conditioner 100. The service server 1612 may provide a service related to the Internet of things (IoT). The service server 1612 may provide status information of the air conditioner 100 and provide a function to control the air conditioner 100 through an application installed in the user terminal 1310. The service server 1612 may also provide a certain function to the air conditioner 100 based on information collected from outside. For example, the service server 1612 may use weather information collected from an external server to provide information such as a recommended set temperature or a recommended function for the air conditioner 100 to the indoor unit 1330 or the user terminal 1310. The service server 1612 communicates with at least one device registered at the user account. The service server 1612 provides information or a service related to a device registered at the user account to the user terminal 1310 logged in with the user account. The service server 1612 forwards a control signal received from the user terminal 1310 logged in with the user account to the device registered at the user account.

The indoor unit 1330 may include an application layer 1620, a framework layer 1630, a driver layer 1640 and a system layer 1650.

The application layer 1620 includes a communication module 1622, a data process 1624 and an air conditioning module 1620.

The communication module 1622 may receive a user input through a remote controller, a touch key, etc. The communication module 1622 may correspond to the aforementioned communication module 212 and the input interface 216. The communication module 1622 may include a Wi-Fi block for processing communication with a server or a user terminal, a remote control block for processing communication with a remote controller, a key block for processing an input through a key, a block for performing other functions, etc.

The data process 1624 includes a Config block for processing an operating system (OS) operation of the device, an operation block for processing various operations of the device, and an option block for processing various functions and options of the device.

The air conditioning module 1626 includes various hardware devices. The air conditioning module 1626 includes a load block 1628 for performing air conditioning operation, a Protect block for protecting a device, and a Sequence block for controlling air flows and refrigerant flows.

The indoor unit 1330 may include a framework layer 1630 for performing a framework operation, a driver layer for performing a driver operation related to input and output, and a system layer 1650 corresponding to an OS.

The machine-readable storage medium may be provided in the form of a non-transitory storage medium. The term ‘non-transitory storage medium’ may mean a tangible device without including a signal, e.g., electromagnetic waves, and may not distinguish between storing data in the storage medium semi-permanently and temporarily. For example, the non-transitory storage medium may include a buffer that temporarily stores data.

In an embodiment, the aforementioned method according to the various embodiments of the present specification may be provided in a computer program product. The computer program product may be a commercial product that may be traded between a seller and a buyer. The computer program product may be distributed in the form of a machine-readable storage medium (e.g., a CD-ROM) or distributed directly between two user devices (e.g., smart phones) or online (e.g., downloaded or uploaded). In the case of the online distribution, at least part of the computer program product (e.g., a downloadable app) may be at least temporarily stored or arbitrarily created in a storage medium that may be readable to a device such as a server of the manufacturer, a server of the application store, or a relay server.

According to an aspect of an embodiment of the present disclosure, provided is a method of controlling an air conditioner. A method of controlling an air conditioner includes receiving an off-control signal to terminate an air conditioning operation of the air conditioner; determining whether the off-control signal to terminate the air conditioning operation is for immediately terminating a fan operation; based on determining that the off-control signal is for immediately terminating the fan operation, stopping a fan of the air conditioner by using a normal termination control; based on determining that the off-control signal is not for immediately terminating the fan operation, determining whether a fan operation termination condition is satisfied; and based on the fan operation termination condition being satisfied, stopping the fan of the air conditioner by using noise prevention control at a rate lower than a revolution per minute (rpm) reduction rate of the fan stopping by using the normal termination control.

In an embodiment of the present disclosure, the stopping of the fan by using the noise prevention control in the second mode may include reducing a fan rpm of the fan in a first section based on a first reduction rate; reducing the fan rpm in a second section in which the fan rpm is at a lower rpm than the fan in the first section and at least at a set rpm, based on a second reduction rate higher than the first reduction rate; and reducing the fan rpm in a third section in which the fan is at a lower rpm than the fan in the second section to 0.

In an embodiment of the present disclosure, the reducing of the fan rpm of the fan in the first section may include controlling a reduction rate of the fan rpm with a set value of the first reduction rate by using proportional-integral-differential (PID) control, the reducing of the fan rpm in the second section may include controlling the reduction rate of the fan rpm with a set value of the second reduction rate by using PID control, and the reducing of the fan rpm to 0 in the third section may include reducing the fan rpm to 0 without PID control.

In an embodiment of the present disclosure, the first section may have a fan rpm of 1000 or more, the second section may have a fan rpm of 500 to less than 1000, and the third section may have a fan rpm of less than 500.

In an embodiment of the present disclosure, the terminating of the fan by using the noise prevention control may include reducing the fan rpm at a set rate by using PID control.

In an embodiment of the present disclosure, the determining of whether the off-control signal is for immediately terminating the fan operation may include identifying whether an automatic drying function is set based on the off-control signal corresponding to a power-off signal requesting power-off of the air conditioner, and determining that the off-control signal is for immediately termination the fan operation based on the automatic drying function not being set.

In an embodiment of the present disclosure, the determining of whether the off-control signal is for immediately terminating the fan operation may include determining that the off-control signal is not for immediately terminating the fan operation based on the off-control signal corresponding to a termination reservation signal requesting powering off the air conditioner after a certain period of time.

In an embodiment of the present disclosure, the termination reservation signal may correspond to at least one of a reservation setting signal to request powering off the air conditioner after a certain period of time, or a sleep mode setting signal to request powering off the air conditioner after a certain period of time after the air conditioning operation is performed in a low-noise mode.

In an embodiment of the present disclosure, the stopping of the fan by using the normal termination control may include based on determining that the off-control signal is for immediately terminating the fan operation, identifying whether a noise prevention mode is set; and based on the noise prevention mode not being set, stopping the fan by using the normal termination control.

In an embodiment of the present disclosure, the stopping of the fan by using the normal termination control may include based on determining that the off-control signal is for immediately terminating the fan operation, identifying whether a current time belongs to a preset noise prevention time zone; and based on the current time does not being within the preset noise prevention time zone, stopping the fan by using the normal termination control in the first mode.

In an embodiment of the present disclosure, the stopping of the fan by using the noise termination control may include identifying whether the air conditioner is operating in a windless mode; and based on the air conditioner operating in the windless mode, stopping the fan by using the normal termination control.

In an embodiment of the present disclosure, the stopping of the fan by using the normal termination control may include stopping the fan by blocking a driving current applied to a fan motor to drive the fan.

In an embodiment of the present disclosure, the stopping of the fan by using the noise prevention control may include controlling the fan rpm reduction rate by controlling a duty ratio of a driving current applied to a fan motor to drive the fan by using PID control.

According to an aspect of an embodiment of the present disclosure, provided also is an air conditioner. The air conditioner includes a fan. The air conditioner also includes a fan operation module for operating the fan. The air conditioner also includes an input interface. The air conditioner also includes a communication module. The air conditioner also includes a memory to store at least one instruction. The air conditioner also includes at least one processor. At least one processor (210) is configured to execute the at least one instruction in the memory to receive an off-control signal to terminate air conditioning operation through the communication module or the input interface, determine whether the off-control signal is for immediately terminating fan operation, based on determining that the off-control signal is the for immediately terminating the fan operation, control the fan operation module to stop the fan by using normal termination control, based on determining that the off-control signal is not for immediately terminating the fan operation, determine whether a fan operation termination condition is satisfied, and based on the fan operation termination condition being satisfied, control the fan operation module to stop the fan by using noise prevention control at a rate lower than a fan revolution per minute (rpm) reduction rate of the fan stopping by using the normal termination control.

In an embodiment of the present disclosure, the at least one processor is configured to execute the at least one instruction in the memory further to: reduce the fan rpm in a first section based on a first reduction rate; reduce the fan rpm in a second section in which the fan rpm is at a lower rpm than the fan in the first section and at least at a set rpm, based on a second reduction rate higher than the first reduction rate; and reduce the fan rpm in a third section in which the fan is at a lower rpm than the fan in the second section to 0.

In an embodiment of the present disclosure, the at least one processor is configured to execute the at least one instruction in the memory further to: identify whether an automatic drying function is set based on the off-control signal corresponding to a power-off signal to request power-off of the air conditioner; determine that the off-control signal is not for immediately terminating the fan operation based on the automatic drying function being set.

In an embodiment of the present disclosure, the at least one processor is configured to execute the at least one instruction in the memory further to: determine that the off-control signal is not for immediately terminating the fan operation based on the off-control signal corresponding to a termination reservation signal requesting powering off the air conditioner after a certain period of time.

In an embodiment of the present disclosure, the at least one processor is configured to execute the at least one instruction in the memory further to: based on determining that the off-control signal is for immediately terminating the fan operation, identify whether a noise prevention mode is set; and based on the noise prevention mode being set, stop the fan by using the noise prevention control; and based on the noise prevention mode not being set, stop the fan by using the normal termination control.

In an embodiment of the present disclosure, the at least one processor is configured to execute the at least one instruction in the memory further to: identify whether the air conditioner is operating in a windless mode; and based on the air conditioner operating in the windless mode, stop the fan by using the normal termination control.

According to an embodiment of the present disclosure, provided is a computer-readable recording medium having recorded thereon a program to cause a computer to perform a method of controlling an air conditioner.