Method and system for low-frequency oil return control for air conditioner

Abstract

The invention provides a method and a system for low-frequency oil return control for an air conditioner. The method comprises the following steps: detecting a running frequency, a suction gas superheat degree, an indoor environment temperature and an outdoor environment temperature of a compressor; when detecting that the running frequency of the compressor is kept for a preset time in the case that the running frequency is lower than a preset oil return frequency, enabling the air conditioner to enter an oil return mode, selecting an initial openness degree of an electronic expansion valve in the air conditioner, an initial rotational speed of an outdoor fan and an initial rotational speed of an indoor fan according to the indoor environment temperature and the outdoor environment temperature, adjusting the openness degree of the electronic expansion valve to be the initial openness degree, adjusting the rotational speed of the outdoor fan to be the initial rotational speed, and adjusting the rotational speed of the indoor fan to be the initial rotational speed; and adjusting the openness degree of the electronic expansion valve, the rotational speed of the outdoor fan and the rotational speed of the indoor fan according to the detected suction gas superheat degree. According to the invention, an oil return effect is achieved by virtue of a pipeline pressure difference, and various adverse factors brought by the traditional increasing-frequency oil return are overcome in case of no influence on the refrigerating capacity need and the running reliability of low-frequency running.

Description

technical field [0001] The invention relates to the field of air conditioners, in particular to a low-frequency oil return control method and system for an air conditioner. Background technique [0002] In traditional air conditioners, when the compressor runs at a lower frequency for a long time, the flow rate of the refrigerant in the system decreases due to the low system pressure, causing the lubricating oil brought out by the refrigerant to be unable to be normally absorbed by the refrigerant. Brought back to the compressor, if the lubricating oil is taken out for a long time and cannot be brought back to the compressor through the circulation of the refrigerant, it is easy to cause wear or burn of the compressor. [0003] In order to solve this problem, the current method is to increase the frequency of the compressor to control the oil return after running at low frequency for a period of time, so that the lubricating oil trapped outside the compressor can be brought ...

AI Technical Summary

Problems solved by technology

However, when the air conditioner is running at low frequency, increasing the frequency and returning oil will break the stable state of the environment, resulting in temperature changes in the room, affecting the comfort of users. The frequent start and stop of the air conditioner makes it too late to form a stable high-speed airflow in the air return pipe, and the lubricating oil cannot be brought back to the compressor by the refrigerant in time, which is not conducive to oil return, and the frequent up-frequency oil return of the air conditioner also causes bad The necessary waste of electricity reduces the utilization efficiency and performance of the air conditioner

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