A kind of electronic expansion valve control method

Abstract

The invention discloses a control method of an electronic expansion valve, including the steps of controlling the opening degree of the electronic expansion valve by adopting a suction pressure control mode after an air conditioning unit is started; judging whether the air conditioning unit exceeds the shortest suction pressure control time and meets the suction gas superheat control condition, and if so, adopting the suction gas superheat control mode is to control the opening degree of the electronic expansion valve. The suction pressure control mode is as follows: when the suction pressure of a compressor is higher than the suction pressure target value, the opening degree of the electronic expansion valve is reduced; when the suction pressure of the compressor is lower than the suction pressure target value, the opening degree of the electronic expansion valve is increased; when the suction pressure of the compressor is equal to the suction pressure target value, the opening degree of the electronic expansion valve is unchanged. The method can prevent the opening degree of the electronic expansion valve from varying due to the adoption of the suction gas superheat control when the air conditioning unit is started, and avoids influences on the life of the electronic expansion valve and the stability of the air conditioning system.

Description

technical field [0001] The present invention relates to the technical field of air conditioners, and more specifically, to a method for controlling an electronic expansion valve. Background technique [0002] In air-conditioning equipment, the method of controlling the suction superheat of the compressor is usually used to adjust the opening or closing of the electronic expansion valve inside the air-conditioning equipment, so that the equipment can operate normally. Generally, when the actual suction superheat is greater than the target suction superheat, the opening of the electronic expansion valve increases; when the actual suction superheat is lower than the target suction superheat, the opening of the electronic expansion valve decreases; the actual suction superheat When it is equal to the target suction superheat degree, the opening degree of the electronic expansion valve remains unchanged. [0003] At present, the control of the suction superheat of the electronic...

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Problems solved by technology

[0004] When the air conditioning unit is started, the suction temperature and suction pressure are in an unstable process. At this time, the use of superheat control will cause the opening of the electronic expansion valve to fluctuate due to the instability of the suction superheat. It affects the life of the electronic expansion valve, and also leads to unstable operation of the air conditioning system and large fluctuations in air conditioning load

[0005] In addition, when the air-conditioning unit is shut down and evacuated, there will also be the above-mentioned problem that the opening of the electronic expansion valve will vary from time to time.

[0006] In addition, during the cooling and defrosting process of the heat pump, due to the switching of the high and low pressure side heat exchangers, the suction superheat will fluctuate greatly. At this time, the suction superheat is used to control the electronic expansion valve, and the electronic expansion valve will appear. The situation of rapid switch, causing the high and low pressure of the system to fluctuate greatly, even generating an alarm or other hazards, causing the unit to fail to operate normally

[0007] Finally, when the suction superheat of the system is very large, the use of suction superheat control will lead to a large or even full opening of the electronic expansion valve, increasing the refrigerant flow into the evaporator and compressor, and increasing the suction pressure , may damage the compressor or other components, causing the unit to fail to operate normally

[0008] Therefore, how to avoid the opening of the electronic expansion valve caused by the suction superheat control when the air-conditioning unit is started, which affects the life of the electronic expansion valve, has become a technical problem to be solved urgently by those skilled in the art.

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