Clothes dryer and control method therefor

Abstract

A clothes dryer may include a drum in which laundry is receivable; a humidity detector to detect a dryness level of the laundry in the drum; and a controller configured to: obtain the dryness level of the laundry in the drum detected by the humidity detector while a first initial drying cycle is performed, determine a weight category of the laundry in the drum from a plurality of weight categories of laundry based on the obtained dryness level, obtain control information based on the determined weight category, and control, according to the obtained control information, a main drying cycle to dry the laundry in the drum after the first initial drying cycle is performed.

1 . A clothes dryer, comprising:
 a drum in which laundry is receivable;   a humidity detector to detect a dryness level of the laundry in the drum; and   a controller configured to:
 obtain the dryness level of the laundry in the drum detected by the humidity detector while a first initial drying cycle to dry the laundry in the drum is performed, 
 determine a weight category of the laundry in the drum from a plurality of weight categories of laundry based on the obtained dryness level, 
 obtain control information based on the determined weight category, and 
 control, according to the obtained control information, a main drying cycle to dry the laundry in the drum after the first initial drying cycle is performed. 
   
     
     
         2 . The clothes dryer of  claim 1 , wherein
 the humidity detector includes a pair of touch electrode sensors in the drum, and   the pair of touch electrode sensors output a pulse signal indicating a moisture content of the laundry in the drum when contacted by the laundry in the drum.   
     
     
         3 . The clothes dryer of  claim 1 , wherein
 the humidity detector includes an electrode sensor configured to output a pulse signal indicating a moisture content of the laundry in the drum, and   the controller is further configured to:
 count a number of times that the pulse signal is greater than or equal to a predetermined reference during each time unit of a plurality of time units that the first initial drying cycle is performed, 
 determine an average of the counted number of times for the plurality of time units, 
 determine whether the average is less than a first threshold, and 
 determine the weight category of the laundry in the drum based on the determination of whether the average is less than the first threshold. 
   
     
     
         4 . The clothes dryer of  claim 1 , wherein
 the humidity detector includes an electrode sensor configured to output a pulse signal indicating a moisture content of the laundry in the drum, and   the controller is further configured to:
 after the weight category is determined, obtain the pulse signal while a second initial drying cycle to dry the laundry in the drum is performed, 
 determine a material category of the laundry in the drum from a plurality of material categories of laundry based on the obtained pulse signal, 
 obtain the control information based on the determined weight category and the determined material category, and 
 control, according to the obtained control information based on the determined weight category and the determined material category, the main drying cycle to dry the laundry in the drum after the second initial drying cycle is performed. 
   
     
     
         5 . The clothes dryer of  claim 4 , wherein
 the controller is further configured to:
 count a first number of times that the pulse signal is greater than or equal to a predetermined reference during each first time unit of a plurality of first time units that the first initial drying cycle is performed, 
 determine a first average of the counted first number of times for the plurality of first time units, 
 count a second number of times that the pulse signal is greater than or equal to the predetermined reference during each second time unit of a plurality of second time units that the second initial drying cycle is performed, 
 determine a second average of the counted first number of times and the counted second number of times for the plurality of first time units and the plurality of second time units, and 
 determine the material category of the laundry in the drum from the plurality of material categories of laundry based on whether a difference between the first average and the second average is greater than or equal to a second threshold. 
   
     
     
         6 . The clothes dryer of  claim 4 , further comprising:
 an input to receive a selection from a user of a target dryness level from among a plurality of dryness levels, wherein   the controller is further configured to:
 count a number of times that the pulse signal is greater than or equal to a predetermined reference during each time unit of a plurality of time units that the second initial drying cycle is performed, 
 determine, while the second initial drying cycle is performed, whether the counted number of times, being less than or equal to a value corresponding to the target dryness level, occurs consecutively more than or equal to a predetermined number of times, the value corresponding to the target dryness level being determined from among a plurality of predetermined values respectively corresponding to the plurality of dryness levels, and 
 when the counted number of times, being less than or equal to the value corresponding to the target dryness level, occurs consecutively more than or equal to a predetermined number of times, terminate the second initial drying cycle and determine the material category of the laundry in the drum from the plurality of material categories of laundry. 
   
     
     
         7 . The clothes dryer of  claim 4 , further comprising:
 a heater to heat air supplied to the drum;   a temperature sensor to measure a temperature of air in the drum; and   a driving motor to drive rotation of the drum, wherein   the controller is further configured to:
 obtain an upper limit temperature, a lower limit temperature, and a driving reference of the driving motor for the first initial drying cycle and the second initial drying cycle; and 
 while the first initial drying cycle and the second initial drying cycle are performed: 
 obtain the temperature measured from the temperature sensor, 
 control the heater to turn off when the obtained temperature is greater than or equal to the upper limit temperature, 
 control the heater to turn on when the obtained temperature is less than or equal to the lower limit temperature, and 
 control the driving motor to drive rotation of the drum according to the driving reference. 
   
     
     
         8 . The clothes dryer of  claim 4 , further comprising:
 a heater to heat air supplied to the drum; and   a temperature sensor to measure a temperature of air in the drum, and   a driving motor to drive rotation of the drum, wherein   the obtained control information based on the determined weight category and the determined material category includes an upper limit temperature and a lower limit temperature respectively corresponding to each combination of a plurality of combinations of the weight category of the plurality of weight categories of laundry and the material category of the plurality of material categories of laundry, and   the controller is further configured to, while the main drying cycle is performed:
 obtain the temperature of air in the drum from the temperature sensor, 
 compare the obtained temperature with the upper limit temperature and the lower limit temperature for a combination of the plurality of combinations for the determined weight category and the determined material category, 
 control the heater to turn on or turn off according to a result of the compared temperature, and 
 control the driving motor to turn on or turn off based on a drive-on duration or a drive-off duration of the driving motor. 
   
     
     
         9 . The clothes dryer of  claim 8 , wherein
 the plurality of material categories of laundry include:
 a first category having a first drying speed and a first moisture content, and 
 a second category having a second drying speed lower than the first drying speed and a second moisture content lower than the first moisture content, and 
   when the determined material category for the laundry in the drum is the second category, the upper limit temperature and the lower limit temperature of the obtained control information based on the determined weight category and the determined material category are respectively lower than when the determined material category for the laundry in the drum is the first category.   
     
     
         10 . The clothes dryer of  claim 8 , wherein
 the heater further includes a first heater and a second heater, and   the obtained control information based on the determined weight category and the determined material category includes information about which heater between the first heater and the second heater is to be used during the main drying cycle.   
     
     
         11 . The clothes dryer of  claim 4 , further comprising:
 a driving motor to drive rotation of the drum,   wherein the obtained control information based on the determined weight category and the determined material category includes, based on the determined weight category of the laundry in the drum, one of repeatedly turning on and turning off the driving motor based on a predetermined time reference, and continuously maintaining the driving motor in an on state.   
     
     
         12 . The clothes dryer of  claim 4 , further comprising:
 an input to receive a selection from a user of a target dryness level from among a plurality of dryness levels, wherein   the controller is further configured to:
 while the main drying cycle is performed, count a number of times that the pulse signal is greater than or equal to a predetermined reference during each time unit of a plurality of time units that the main drying cycle is performed, and determine whether the counted number of times, being less than or equal to a predetermined value, occurs more than or equal to a predetermined number of times; 
 when the counted number of times, being greater than or equal to the predetermined value, occurs more than or equal to the predetermined number of times, set an additional drying time based on at least one of a corresponding determination time, the determined weight category and the determined material category, and the target dryness level, and 
 control the main drying cycle to be further performed for the set additional drying time. 
   
     
     
         13 . A method for controlling a drying operation of a clothes dryer including a drum in which laundry is receivable, a heater to heat air supplied to the drum, a temperature sensor to measure a temperature of air in the drum, a driving motor to drive rotation of the drum, and a pair of touch electrode sensors disposed in the drum to output a pulse signal indicating a moisture content of the laundry in the drum when contacted by the laundry in the drum,
 the method comprising:   receiving a dry start command;   performing a first initial drying cycle, in response to receiving the dry start command;   counting a first number of times that the pulse signal is greater than or equal to a predetermined reference during each first time unit of a plurality of first time units that the first initial drying cycle is performed;   determining a first average of the counted first number of times for the plurality of first time units;   comparing the first average with a first threshold; and   determining a weight category of the laundry in the drum from a plurality of weight categories of laundry according to a result of the compared first average.   
     
     
         14 . The method of  claim 13 , further comprising:
 performing a second initial drying cycle after performing the first initial drying cycle;   counting a second number of times that the pulse signal is greater than or equal to the predetermined reference during each second time unit of a plurality of second time units that the second initial drying cycle is performed;   determining a second average of the counted second number of times for the plurality of second time units;   comparing a difference between the first average and the second average with a second threshold; and   determining a material category of the laundry in the drum from a plurality of material categories of laundry according to a result of the compared difference.   
     
     
         15 . The method of  claim 14 , further comprising:
 receiving a selection from a user of a target dryness level from among a plurality of dryness levels;   performing a main drying cycle;   counting a third number of times that the pulse signal is greater than or equal to a predetermined reference during each third time unit of a plurality of third time units that the main drying cycle is performed;   determining whether the counted third number of times, being less than or equal to a predetermined value, occurs greater than or equal to a predetermined number of times during the plurality of third time units;   based on the determining that the counted third number of times, being less than or equal to the predetermined value, occurs greater than or equal to the predetermined number of times, setting an additional drying time based on at least one of a corresponding determination time, the determined weight category and the determined material category, and the target dryness level; and   performing the main drying cycle for the determined additional drying time and,   after the main drying cycle for the determined additional drying time is completed, turning off the heater and performing a cooling cycle.