Air conditioner for removing foreign substances from indoor heat exchanger and method of operating the same

An air conditioner, comprising:

• a compressor configured to compress and discharge a refrigerant;
• an indoor heat exchanger configured to exchange heat between the refrigerant and indoor air;
• an indoor fan;
• a sensor unit including at least one sensor;
• and
• a controller configured to control the compressor so that a current temperature of the indoor heat exchanger corresponds to a target temperature, wherein the controller is further configured to:
• perform a primary control of the compressor, using a first target temperature as the target temperature corresponding to a dew point temperature of the indoor air and the current temperature of the indoor heat exchanger;
• perform a secondary control of the compressor, using a second target temperature below 0° C. as the target temperature, which is lower than the first target temperature and the current temperature of the indoor heat exchanger;
• when an amount of moisture contained in the indoor air corresponding to absolute humidity is equal to or greater than a preset reference, perform a first drying operation;
• and
• when the amount of moisture contained in the indoor air is less than the preset reference, perform a second drying operation and repeatedly perform at least one of the primary control or the secondary control, wherein the first drying operation and the second drying operation are different in at least one of a rotational speed of the indoor fan or a rotational time of the indoor fan.