Washing machine and control method therefor

A washing machine comprising:

• a main body
• a drum disposed in the main body for receiving laundry;
• a motor coupled to the drum for rotating the drum;
• a drying unit disposed in the main body for supplying air to inside of the drum, the drying unit including a heater and a fan;
• a filter unit coupled to the drying unit for filtering lint in air to be supplied to the drying unit, the filter unit including a filter;
• a cleaning unit coupled to the filter unit for removing the lint clogged on the filter, the cleaning unit including a spray nozzle for spraying water toward the filter;
• and
• a processor configured to;
• control the cleaning unit, in a first drying step, to spray water for a predetermined first interval while the drum rotates at a first rotation speed, and the heater and the fan are operated;
• and
• control the cleaning unit, in a second drying step, to spray water for a predetermined second interval while the drum rotates at a second rotation speed, and the heater is not operated, and the fan is operated;
• and
• wherein the second interval is shorter than the first interval, and the second rotation speed is higher than the first rotation speed.