Multi-split system and control method thereof

Abstract

A multi-split system and a control method thereof are provided. The control method comprises the steps of: obtaining a discharge superheating degree from a compressor and determining whether the discharge superheating degree is less than a first predetermined superheating degree; if the discharge superheating degree is less than the first predetermined superheating degree, further obtaining a pre-valve supercooling degree of a cooling throttle member, and determining whether the pre-valve supercooling degree is less than a predetermined supercooling degree; and if the pre-valve supercooling degree is less than the predetermined supercooling degree, controlling the degree of opening of the cooling throttle member to remain unchanged, adjusting a vent target superheating degree of a plurality of indoor units to a first target superheating degree, and controlling an indoor throttle member of the plurality of the indoor units according to the first target superheating degree.

What is claimed is: 
     
         1 . A control method for multi-split system comprising:
 an outdoor unit;   a distribution device; and   a plurality of indoor units,   wherein the outdoor unit comprises a compressor, the distribution device comprises a main loop, a cooling loop, and a refrigeration throttling element disposed between an outlet of the main loop and an inlet of the cooling loop and configured to perform a throttling control on a refrigerant entering the cooling loop when the multi-split system is operated in a main refrigeration mode or a pure refrigeration mode, and each of the plurality of the indoor units is provided with an indoor throttling element; the method comprising:   acquiring a discharge superheating degree of the compressor, and determining whether the discharge superheating degree is less than a first preset superheating degree;   acquiring an inlet supercooling degree of the refrigeration throttling element, and determining whether the inlet supercooling degree of the refrigeration throttling element is less than a preset supercooling degree if the discharge superheating degree is less than the first preset superheating degree; and   controlling an opening of the refrigeration throttling element to remain unchanged and adjusting a target outlet superheating degree of the plurality of the indoor units to a first target superheating degree if the inlet supercooling degree of the refrigeration throttling element is less than the preset supercooling degree, and controlling the indoor throttling elements of the plurality of the indoor units according to the first target superheating degree.   
     
     
         2 . The control method according to  claim 1 , further comprising:
 controlling the refrigeration throttling element according to a target outlet superheating degree of the cooling loop; and   adjusting the target outlet superheating degree of the plurality of the indoor units to a second target superheating degree when the inlet supercooling degree of the refrigeration throttling element is greater than or equal to the preset supercooling degree, wherein the second target superheating degree is less than the first target superheating degree.   
     
     
         3 . The control method according to  claim 1 , further comprising:
 controlling the refrigeration throttling element according to a target outlet superheating degree of the cooling loop; and   adjusting the target outlet superheating degree of the plurality of the indoor units to a second target superheating degree when the discharge superheating degree is greater than or equal to the first preset superheating degree and less than a second preset superheating degree, wherein the second target superheating degree is less than the first target superheating degree.   
     
     
         4 . The control method according to  claim 3 , further comprising:
 controlling the refrigeration throttling element according to the target outlet superheating degree of the cooling loop; and   adjusting the target outlet superheating degree of the plurality of the indoor units to a third target superheating degree when the discharge superheating degree is greater than or equal to the second preset superheating degree, wherein the third target superheating degree is less than the second target superheating degree.   
     
     
         5 . The control method according to  claim 1 , further comprising:
 determining whether the compressor is in a startup phase; and   controlling the refrigeration throttling element to maintain a preset opening if the compressor is in the startup phase.   
     
     
         6 . A multi-split system, comprising:
 an outdoor unit, comprising a compressor;   a distribution device, comprising:
 a main loop, 
 a cooling loop, and 
 a refrigeration throttling element, disposed between an outlet of the main loop and an inlet of the cooling loop and configured to perform a throttling control on a refrigerant entering the cooling loop when the multi-split system is operated in a main refrigeration mode or a pure refrigeration mode; 
   a plurality of indoor units, each of the plurality of the indoor units being provided with an indoor throttling element; and   a control device, configured to:   acquire a discharge superheating degree of the compressor, and determine whether the discharge superheating degree is less than a first preset superheating degree;   acquire an inlet supercooling degree of the refrigeration throttling element, and determine whether the inlet supercooling degree of the refrigeration throttling element is less than a preset supercooling degree if the discharge superheating degree is less than the first preset superheating degree; and   control an opening of the refrigeration throttling element to remain unchanged and adjust a target outlet superheating degree of the plurality of the indoor units to a first target superheating degree when the inlet supercooling degree of the refrigeration throttling element is less than the preset supercooling degree, and control the indoor throttling elements of the plurality of the indoor units according to the first target superheating degree.   
     
     
         7 . The multi-split system according to  claim 6 , wherein the control device is configured to control the refrigeration throttling element according to a target outlet superheating degree of the cooling loop, and adjust the target outlet superheating degree of the plurality of the indoor units to a second target superheating degree when the inlet supercooling degree of the refrigeration throttling element is greater than or equal to the preset supercooling degree, wherein the second target superheating degree is less than the first target superheating degree. 
     
     
         8 . The multi-split system according to  claim 6 , wherein the control device is configured to control the refrigeration throttling element according to a target outlet superheating degree of the cooling loop, and adjust the target outlet superheating degree of the plurality of the indoor units to a second target superheating degree when the discharge superheating degree is greater than or equal to the first preset superheating degree and less than a second preset superheating degree, wherein the second target superheating degree is less than the first target superheating degree. 
     
     
         9 . The multi-split system according to  claim 8 , wherein the control device is configured to control the refrigeration throttling element according to the target outlet superheating degree of the cooling loop, and adjust the target outlet superheating degree of the plurality of the indoor units to a third target superheating degree when the discharge superheating degree is greater than or equal to the second preset superheating degree, wherein the third target superheating degree is less than the second target superheating degree. 
     
     
         10 . The multi-split system according to  claim 6 , wherein the control device is further configured to determine whether the compressor is in a startup phase, and control the refrigeration throttling element to maintain a preset opening when it is determined that the compressor is in the startup phase. 
     
     
         11 . A non-transitory computer-readable storage medium having stored therein computer programs that, when executed by a processor, cause the processor to:
 acquire a discharge superheating degree of the compressor, and determining whether the discharge superheating degree is less than a first preset superheating degree;   acquire an inlet supercooling degree of the refrigeration throttling element, and determining whether the inlet supercooling degree of the refrigeration throttling element is less than a preset supercooling degree if the discharge superheating degree is less than the first preset superheating degree; and   control an opening of the refrigeration throttling element to remain unchanged and adjusting a target outlet superheating degree of the plurality of the indoor units to a first target superheating degree if the inlet supercooling degree of the refrigeration throttling element is less than the preset supercooling degree, and controlling the indoor throttling elements of the plurality of the indoor units according to the first target superheating degree.