Method and device for controlling refrigerant distribution of multi-split air-conditioning system

Abstract

A method and a device for controlling refrigerant distribution of a multi-split air-conditioning system are disclosed in the present disclosure. The method includes: when the system enters a main heating mode, controlling the second electronic expansion valve to close; controlling an electronic expansion valve corresponding to a cooling indoor unit to perform an opening adjustment; when an opening of the electronic expansion valve corresponding to the cooling indoor unit reaches a maximum opening, calculating a target opening of the second electronic expansion valve according to a total opening and the maximum opening of the electronic expansion valve corresponding to the cooling indoor unit; and controlling the second electronic expansion valve according to the target opening. With the method, the cooling effect of the cooling indoor unit is ensured and the liquid strike on the compressor may be avoided under the main heating mode.

1 . A method for controlling refrigerant distribution of a multi-split air-conditioning system, wherein, the multi-split air-conditioning system comprises a re-cooling system and a flow distributing device, the re-cooling system comprises a first heat exchanger, a second heat exchanger, a first electronic expansion valve and a second electronic expansion valve, and the method comprises:
 when the multi-split air-conditioning system enters a main heating mode, controlling the second electronic expansion valve to close;   controlling an electronic expansion valve corresponding to a cooling indoor unit to perform an opening adjustment;   when an opening of the electronic expansion valve corresponding to the cooling indoor unit reaches a maximum opening, calculating a target opening of the second electronic expansion valve according to a total opening and the maximum opening of the electronic expansion valve corresponding to the cooling indoor unit; and   controlling the second electronic expansion valve according to the target opening.   
     
     
         2 . The method according to  claim 1 , wherein, the total opening is obtained according to following acts of:
 when the multi-split air-conditioning system enters a pure heating mode, obtaining a discharge superheat; and   calculating the total opening using a Proportional-Integral PI algorithm according to the discharge superheat.   
     
     
         3 . The method according to  claim 1 , wherein, the target opening of the second electronic expansion valve is calculated by a formula of:
   Δ EXV 2= EXV 2( PI )- EV (cooling indoor) MAX *( A   EV(cooling indoor)   /A   EXV2 ),
   
       where, ΔEXV2 is the target opening of the second electronic expansion valve, EXV2(PI) is the total opening, EV(cooling indoor)MAX is the maximum opening of the electronic expansion valve corresponding to the cooling indoor unit, A EV(cooling indoor)  is a valve circulating area of the electronic expansion valve corresponding to the cooling indoor unit, and A EXV2  is a valve circulating area of the second electronic expansion valve. 
     
     
         4 . A device for controlling refrigerant distribution of a multi-split air-conditioning system, wherein, the multi-split air-conditioning system comprises a re-cooling system and a flow distributing device, the re-cooling system comprises a first heat exchanger, a second heat exchanger, a first electronic expansion valve and a second electronic expansion valve, and the device comprises:
 a first control component, configured to control the second electronic expansion valve to close when the multi-split air-conditioning system enters a main heating mode;   a second control component, configured to control an electronic expansion valve corresponding to a cooling indoor unit to perform an opening adjustment;   a calculating component, configured to calculate a target opening of the second electronic expansion valve according to a total opening and a maximum opening of the electronic expansion valve corresponding to the cooling indoor unit when an opening of the electronic expansion valve corresponding to the cooling indoor unit reaches the maximum opening; and   a third control component, configured to control the second electronic expansion valve according to the target opening.   
     
     
         5 . The device according to  claim 4 , wherein, the total opening is obtained according to following acts:
 when the multi-split air-conditioning system enters a pure heating mode, obtaining a discharge superheat; and   calculating the total opening using a PI algorithm according to the discharge superheat.   
     
     
         6 . The device according to  claim 4 , wherein, the target opening of the second electronic expansion valve is calculated by a formula of:
   Δ EXV 2= EXV 2( PI )- EV (cooling indoor) MAX *( A   EV(cooling indoor)   /A   EXV2 ),
   
       where, ΔEXV2 is the target opening of the second electronic expansion valve, EXV2(PI) is the total opening, EV(cooling indoor)MAX is the maximum opening of the electronic expansion valve corresponding to the cooling indoor unit, A EV(cooling indoor)  is a valve circulating area of the electronic expansion valve corresponding to the cooling indoor unit, and A EXV2  is a valve circulating area of the second electronic expansion valve. 
     
     
         7 . The method according to  claim 2 , wherein, the target opening of the second electronic expansion valve is calculated by a formula of:
   Δ EXV 2= EXV 2( PI )- EV (cooling indoor) MAX *( A   EV(cooling indoor)   /A   EXV2 ),
   
       where, ΔEXV2 is the target opening of the second electronic expansion valve, EXV2(PI) is the total opening, EV(cooling indoor)MAX is the maximum opening of the electronic expansion valve corresponding to the cooling indoor unit, A EV(cooling indoor)  is a valve circulating area of the electronic expansion valve corresponding to the cooling indoor unit, and A EXV2  is a valve circulating area of the second electronic expansion valve. 
     
     
         8 . The device according to  claim 5 , wherein, the target opening of the second electronic expansion valve is calculated by a formula of:
   Δ EXV 2= EXV 2( PI )- EV (cooling indoor) MAX *( A   EV(cooling indoor)   /A   EXV2 ),
   
       where, ΔEXV2 is the target opening of the second electronic expansion valve, EXV2(PI) is the total opening, EV(cooling indoor)MAX is the maximum opening of the electronic expansion valve corresponding to the cooling indoor unit, A EV(cooling indoor)  is a valve circulating area of the electronic expansion valve corresponding to the cooling indoor unit, and A EXV2  is a valve circulating area of the second electronic expansion valve. 
     
     
         9 . A multi-split air-conditioning system comprising a re-cooling system, a flow distributing device and a controller, the re-cooling system comprises a first heat exchanger, a second heat exchanger, a first electronic expansion valve and a second electronic expansion valve, and the controller is configured to:
 when the multi-split air-conditioning system enters a main heating mode, control the second electronic expansion valve to close;   control an electronic expansion valve corresponding to a cooling indoor unit to perform an opening adjustment;   when an opening of the electronic expansion valve corresponding to the cooling indoor unit reaches a maximum opening, calculate a target opening of the second electronic expansion valve according to a total opening and the maximum opening of the electronic expansion valve corresponding to the cooling indoor unit; and   control the second electronic expansion valve according to the target opening.   
     
     
         10 . The system according to  claim 9 , wherein the total opening is obtained according to following acts of:
 when the multi-split air-conditioning system enters a pure heating mode, obtaining a discharge superheat; and   calculating the total opening using a Proportional-Integral PI algorithm according to the discharge superheat.   
     
     
         11 . The system according to  claim 9 , wherein, the target opening of the second electronic expansion valve is calculated by a formula of:
   Δ EXV 2= EXV 2( PI )- EV (cooling indoor) MAX *( A   EV(cooling indoor)   /A   EXV2 ),
   
       where, ΔEXV2 is the target opening of the second electronic expansion valve, EXV2(PI) is the total opening, EV(cooling indoor)MAX is the maximum opening of the electronic expansion valve corresponding to the cooling indoor unit, A EV(cooling indoor)  is a valve circulating area of the electronic expansion valve corresponding to the cooling indoor unit, and A EXV2  is a valve circulating area of the second electronic expansion valve. 
     
     
         12 . The system according to  claim 10 , wherein, the target opening of the second electronic expansion valve is calculated by a formula of:
   Δ EXV 2= EXV 2( PI )- EV (cooling indoor) MAX *( A   EV(cooling indoor)   /A   EXV2 ),
   
       where, ΔEXV2 is the target opening of the second electronic expansion valve, EXV2(PI) is the total opening, EV(cooling indoor)MAX is the maximum opening of the electronic expansion valve corresponding to the cooling indoor unit, A EV(cooling indoor)  is a valve circulating area of the electronic expansion valve corresponding to the cooling indoor unit, and A EXV2  is a valve circulating area of the second electronic expansion valve.