Method for controlling electronic expansion valve of air conditioner

Abstract

A method for controlling an electronic expansion valve (EEV) in an air conditioner using a compressor includes the steps of: (a) opening the EEV completely when a power is applied to the air conditioner in stand-by mode; (b) closing the EEV completely when the air conditioner starts a cooling or a heating operation; (c) calculating an indoor heat load; (d) calculating a reference opening pulse frequency of the EEV; and (e) controlling in a stepwise manner an opening pulse frequency of the EEV based on the reference opening pulse frequency of the EEV. The opening pulse frequency of the EEV is controlled in a stepwise manner until it reaches the reference opening pulse frequency of the EEV.

1 . A method for controlling an electronic expansion valve (EEV) in an air conditioner using a compressor, the method comprising the steps of:
 (a) opening the EEV completely when a power is applied to the air conditioner in stand-by mode;   (b) closing the EEV completely when the air conditioner starts a cooling or a heating operation;   (c) calculating an indoor heat load based on an indoor and an outdoor temperature and a difference between the indoor temperature and a target temperature;   (d) calculating a reference opening pulse frequency of the EEV based on the calculated indoor heat load, the indoor and the outdoor temperature, and a reference operating frequency of the compressor; and   (e) controlling in a stepwise manner an opening pulse frequency of the EEV based on the reference opening pulse frequency of the EEV until it reaches the reference opening pulse frequency of the EEV.   
   
   
       2 . The method of  claim 1 , wherein the step (e) includes the steps of:
 (e1) controlling the opening pulse frequency of the EEV at a first start-up pulse frequency for a first time period;   (e2) controlling the opening pulse frequency of the EEV at a second start-up pulse frequency for a second time period;   (e3) controlling the opening pulse frequency of the EEV at a third start-up pulse frequency for a third time period;   (e4) controlling the opening pulse frequency of the EEV at a fourth start-up pulse frequency for a fourth time period; and   (e5) controlling the opening pulse frequency of the EEV at the reference opening pulse frequency.   
   
   
       3 . The method of  claim 2 , wherein the first to the third start-up frequency are lower than the reference opening pulse frequency in an increasing order and the fourth start-up pulse frequency is greater than the reference opening pulse frequency. 
   
   
       4 . The method of  claim 2 , wherein the first to the fourth time period have an identical time duration. 
   
   
       5 . The method of  claim 2 , wherein the fourth start-up pulse frequency is determined to keep an increasing rate of a discharge pressure of the compressor to be lower than a specific level even if an operating frequency of the compressor reaches its maximum level.