Air conditioner and control method therefor

Abstract

An air conditioner is provided. The air conditioner includes an indoor unit including an expansion valve and an indoor heat exchanger, a compressor configured to supply a refrigerant to the indoor unit, a compressor inlet pressure sensor configured to detect a compressor inlet pressure corresponding to a pressure of the refrigerant flowing into the compressor from an accumulator, memory storing one or more computer programs, and one or more processors communicatively coupled to the compressor inlet pressure sensor and the memory, wherein the one or more computer programs include computer-executable instructions that, when executed by the one or more processors individually or collectively, cause the air conditioner to adjust an opening degree of the expansion valve of the indoor unit based on the compressor inlet pressure during a defrosting operation.

What is claimed is: 
     
         1 . An air conditioner comprising:
 an indoor unit comprising an expansion valve and an indoor heat exchanger;   a compressor configured to supply a refrigerant to the indoor unit;   a compressor inlet pressure sensor configured to detect a compressor inlet pressure corresponding to a pressure of the refrigerant flowing into the compressor from an accumulator;   memory storing one or more computer programs; and   one or more processors communicatively coupled to the compressor inlet pressure sensor and the memory,   wherein the one or more computer programs include computer-executable instructions that, when executed by the one or more processors individually or collectively, cause the air conditioner to:
 adjust an opening degree of the expansion valve of the indoor unit based on the compressor inlet pressure during a defrosting operation. 
   
     
     
         2 . The air conditioner of  claim 1 , wherein the one or more computer programs further include computer-executable instructions that, when executed by the one or more processors individually or collectively, cause the air conditioner to adjust the opening degree of the expansion valve to allow the compressor inlet pressure to be maintained within a defined pressure range. 
     
     
         3 . The air conditioner of  claim 2 , wherein the one or more computer programs further include computer-executable instructions that, when executed by the one or more processors individually or collectively, cause the air conditioner to:
 increase the opening degree of the expansion valve based on the compressor inlet pressure becoming less than a defined lower limit, and   decrease the opening degree of the expansion valve based on the compressor inlet pressure becoming greater than a defined upper limit.   
     
     
         4 . The air conditioner of  claim 2 , wherein the one or more computer programs further include computer-executable instructions that, when executed by the one or more processors individually or collectively, cause the air conditioner to:
 stepwise reduce the opening degree of the expansion valve to a defined reference opening degree in response to entering the defrosting operation, and   adjust the opening degree of the expansion valve based on the compressor inlet pressure.   
     
     
         5 . The air conditioner of  claim 1 , further comprising:
 a compressor outlet temperature sensor configured to detect a discharge temperature of the refrigerant discharged from the compressor,   wherein the one or more computer programs further include computer-executable instructions that, when executed by the one or more processors individually or collectively, cause the air conditioner to decrease a frequency of the compressor while increasing the opening degree of the expansion valve, based on the discharge temperature of the refrigerant becoming higher than a defined first threshold temperature during the defrosting operation.   
     
     
         6 . The air conditioner of  claim 5 , wherein the one or more computer programs further include computer-executable instructions that, when executed by the one or more processors individually or collectively, cause the air conditioner to terminate the defrosting operation based on the discharge temperature of the refrigerant becoming higher than a second threshold temperature higher than the first threshold temperature. 
     
     
         7 . The air conditioner of  claim 5 , further comprising:
 a compressor outlet pressure sensor configured to detect a compressor outlet pressure corresponding to a pressure of the refrigerant discharged from the compressor,   wherein the one or more computer programs further include computer-executable instructions that, when executed by the one or more processors individually or collectively, cause the air conditioner to:
 determine a discharge superheat of the compressor based on the discharge temperature of the refrigerant and a condensation temperature converted from the compressor outlet pressure, and 
 terminate the defrosting operation based on the discharge superheat of the compressor becoming less than a defined threshold value. 
   
     
     
         8 . The air conditioner of  claim 1 , wherein the one or more computer programs further include computer-executable instructions that, when executed by the one or more processors individually or collectively, cause the air conditioner to control the compressor inlet pressure sensor to detect the compressor inlet pressure at defined detection periods. 
     
     
         9 . A method for controlling an air conditioner comprising an indoor unit including an expansion valve and a compressor configured to supply a refrigerant to the indoor unit, the method comprising:
 detecting a compressor inlet pressure corresponding to a pressure of the refrigerant flowing into the compressor from an accumulator during a defrosting operation; and   adjusting an opening degree of the expansion valve of the indoor unit based on the compressor inlet pressure.   
     
     
         10 . The method of  claim 9 , wherein the opening degree of the expansion valve is adjusted to allow the compressor inlet pressure to be maintained within a defined pressure range. 
     
     
         11 . The method of  claim 10 , wherein the adjusting of the opening degree of the expansion valve comprises:
 increasing the opening degree of the expansion valve based on the compressor inlet pressure becoming less than a defined lower limit; and   decreasing the opening degree of the expansion valve based on the compressor inlet pressure becoming greater than a defined upper limit.   
     
     
         12 . The method of  claim 10 , wherein the adjusting of the opening degree of the expansion valve is performed based on the compressor inlet pressure, after stepwise reducing the opening degree of the expansion valve to a defined reference opening degree in response to entering the defrosting operation. 
     
     
         13 . The method of  claim 9 , further comprising:
 detecting a discharge temperature of the refrigerant discharged from the compressor during the defrosting operation,   wherein the adjusting of the opening degree of the expansion valve comprises decreasing a frequency of the compressor while increasing the opening degree of the expansion valve, based on the discharge temperature of the refrigerant becoming higher than a defined first threshold temperature.   
     
     
         14 . The method of  claim 13 , wherein the defrosting operation is terminated based on the discharge temperature of the refrigerant becoming higher than a second threshold temperature higher than the first threshold temperature. 
     
     
         15 . The method of  claim 13 , further comprising:
 detecting a compressor outlet pressure corresponding to a pressure of the refrigerant discharged from the compressor; and   determining a discharge superheat of the compressor based on the discharge temperature of the refrigerant and a condensation temperature converted from the compressor outlet pressure,   wherein the defrosting operation is terminated based on the discharge superheat of the compressor becoming less than a defined threshold value.   
     
     
         16 . The method of  claim 9 , further comprising:
 detecting, by a compressor inlet pressure sensor, the compressor inlet pressure at defined detection periods.   
     
     
         17 . One or more non-transitory computer-readable storage media storing computer-executable instructions that, when executed by an air conditioner comprising an indoor unit including an expansion valve and a compressor configured to supply a refrigerant to the indoor unit, cause an air conditioner to perform operations, the operations comprising
 detecting a compressor inlet pressure corresponding to a pressure of the refrigerant flowing into the compressor from an accumulator during a defrosting operation; and   adjusting an opening degree of the expansion valve of the indoor unit based on the compressor inlet pressure.   
     
     
         18 . The one or more non-transitory computer-readable storage media of  claim 17 , wherein the opening degree of the expansion valve is adjusted to allow the compressor inlet pressure to be maintained within a defined pressure range. 
     
     
         19 . The one or more non-transitory computer-readable storage media of  claim 18 , wherein the adjusting of the opening degree of the expansion valve comprises:
 increasing the opening degree of the expansion valve based on the compressor inlet pressure becoming less than a defined lower limit; and   decreasing the opening degree of the expansion valve based on the compressor inlet pressure becoming greater than a defined upper limit.   
     
     
         20 . The one or more non-transitory computer-readable storage media of  claim 18 , wherein the adjusting of the opening degree of the expansion valve is performed based on the compressor inlet pressure, after stepwise reducing the opening degree of the expansion valve to a defined reference opening degree in response to entering the defrosting operation.