OIL-RETURN CONTROL METHOD, DEVICE AND OUTDOOR UNIT OF VARIABLE-FREQUENCY AIR CONDITIONER

摘要

An oil-return control method, a device and an outdoor unit of a variable-frequency air conditioner. In the outdoor unit (1) of the air conditioner, two ends of an electronic expansion valve (14) of the outdoor unit respectively communicate with an oil separator (12) and a variable-frequency compressor (11). The oil-return control method comprises: detecting a first running frequency of the variable-frequency compressor (11); determining a first opening value of the corresponding electronic expansion valve (14) of the outdoor unit upon the first running frequency and the pre-stored corresponding relationships; and adjusting the opening of the electronic expansion valve (14) to the first opening value. The method can solve the problem that the capacity of the air conditioner decreases while the variable-frequency compressor runs in low frequency and middle frequency range.