Control method for multi-split air conditioner outdoor unit electronic expansion valves during heating

Abstract

The invention discloses a control method for a multi-split air conditioner outdoor unit electronic expansion valves during heating. The method comprises the steps that 1, the average target opening A1 of all electronic expansion valves is calculated out; 2, whether the average target opening A1 is smaller than Amax or not is judged, if yes, the third steps is executed, and if not, the fourth step is executed; 3, half of the electronic expansion valves are switched off, the number of steps of the other half of the electronic expansion valves is adjusted to be 2A1, the switched-on electronic expansion valves are monitored in real time, and if the requirement that the openings of the switched-on electronic expansion valves are larger than the disengaging value At is met, all the electronic expansion valves are switched on with the same number of steps; 4, the number of the steps of all the electronic expansion valves are adjusted to be A1 for operation; 5, after operation is conducted for 20-40 seconds, whether the average target opening of all the electronic expansion valves at the moment is smaller than Amax or not is judged, and if yes, the third step is executed again. According to the method, it can be guaranteed that the openings of the outdoor unit electronic expansion valves are kept within the reasonable range.

Description

technical field [0001] The invention relates to the field of air conditioning, and specifically relates to a control method for electronic expansion valves of multi-connected outdoor units during heating, specifically, a control method for multi-connected outdoor units with multiple electronic expansion valves connected in parallel. Background technique [0002] The electronic expansion valve of the external unit of the multi-connected air conditioner unit plays a role in reducing the pressure and throttling the refrigerant in the heating mode. The multi-connected unit includes an outdoor unit and multiple indoor units. The system is more complex, there are more refrigerants, and the control accuracy of the refrigerant is also higher. Therefore, each outdoor unit generally includes 2 or more electronic expansion valves connected in parallel. In this way, a greater adjustment range can be obtained. However, under some working conditions, such as when the number of internal u...

AI Technical Summary

Problems solved by technology

However, under some working conditions, such as when the number of internal units is small, or the room temperature is high, and the system load is small, the opening of the electronic expansion valve of the external unit needs to be reduced. However, when the opening of the electronic expansion valve is small, there is generally a In the flow uncontrollable area, such as when the opening is 0 to 60 steps, the flow is not proportional to the opening, and the opening of multiple electronic expansion valves connected in parallel is the same, so the opening of each electronic expansion valve is likely to be the same. It just falls in the uncontrollable flow area of ​​the electronic expansion valve, which leads to the instability of the control of the refrigerant by the electronic expansion valve of the external unit, which obviously does not meet the demand for precise adjustment of the refrigerant and affects the stability of the system

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