Control method, control device and control system for initial opening degree of electronic expansion valve

Abstract

The invention provides a control method, a control device and a control system for the initial opening degree of an electronic expansion valve. The control method comprises the steps that S1, an outdoor environment temperature T is detected; S2, according to a preset P-T relation, an initial opening degree value P, corresponding to the outdoor environment temperature T, of the electronic expansion valve is calculated; and S3, the electronic expansion valve is operated to the corresponding value P. According to the control method, the control device and the control system for the initial opening degree of the electronic expansion valve, the outdoor environment temperature T is detected and the initial opening degree value P of the electronic expansion valve is calculated according to the preset P-T relation, so that it is guaranteed that a compressor can establish superheat degrees of exhausting and oil temperature at low temperature quickly, pressure relieving at high temperature is ensured at the same time, and reliable operation of the compressor and a complete machine is ensured.

Description

technical field [0001] The invention relates to the field of air conditioning control, in particular to a control method, control device and control system for the initial opening of an electronic expansion valve. Background technique [0002] In the prior art, the control method for the initial opening degree of the electronic expansion valve of the air conditioner is basically single-point control, that is, the electronic expansion valve is given an initial value when the cooling or heating is started, and this value does not change within a preset period of time after the start-up. Change, after the preset time, it will enter the free adjustment mode. [0003] However, this control method in the prior art has great defects. Under refrigeration conditions, the initial opening of a single point should take into account the low-temperature exhaust, the establishment of oil temperature superheat, and the high-temperature pressure unloading. It is difficult to do this in real...

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Problems solved by technology

[0003] However, there is a big defect in this control method in the prior art

Under refrigeration conditions, the initial opening of a single point should take into account the low-temperature exhaust, the establishment of oil temperature superheat and the high-temperature pressure unloading. It is difficult to do this in reality. Improper high-temperature refrigeration pressure protects the shutdown phenomenon; under heating conditions, the initial valve step setting is too large, which will lead to a long time for the oil temperature superheat of the compressor to be established under low-temperature conditions, which is not good for the reliability of the compressor. If the setting is too small, the maximum heating pressure of the unit will be too high

These problems are particularly prominent in fixed frequency machines

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