A method for controlling oil return in a multi-connected air conditioning system

Abstract

A method for controlling oil return of a multi-connected air conditioning system, the control method includes the following steps: step S1, calculating the oil discharge amount L1 of the system; step S2, calculating the cumulative oil discharge amount L of the system according to the operating state of the air conditioning system, and then according to The relationship between the cumulative oil output L of the system and the oil return of the compressor; step S3, the air-conditioning system operates in the oil-return operation mode, adjusts the air-conditioning system to the refrigeration mode, and adjusts the operating frequency of the compressor to run at the lowest frequency of the oil-return frequency. The outdoor electronic expansion valve reaches the first preset opening degree, the fan of the indoor heat exchanger is stopped, and according to the operation mode of the air conditioning system in step S1, the opening degree B1 of the indoor electronic expansion valve of the non-operating indoor unit is increased and the operating mode is The opening degree B2 of the indoor electronic expansion valve of the indoor unit in the air supply mode, step S4, adjust the operation time of the oil return operation mode according to the magnitude relationship between the compressor operating frequency and the minimum allowable oil return frequency.

Description

technical field [0001] The invention relates to the technical field of air-conditioning oil return control, in particular to a method for controlling oil return of a multi-connected air-conditioning system. Background technique [0002] Generally, the air conditioning system will enter the oil return operation mode after running for a period of time, and the lubricating oil will be returned to the compressor. At present, the existing air conditioning system will fix the operating time of oil return in the oil return operation mode. Such a control method may cause the compressor to run short of oil, which will lead to increased compressor power consumption, heat generation and component wear. It will reduce the service life of the compressor, or even burn the compressor. In addition, the existing air-conditioning system operates in the cooling mode when the oil-return operation mode is operated, and the indoor unit is cooled. If the air-conditioning system operates the heati...

AI Technical Summary

Problems solved by technology

At present, the existing air conditioning system will fix the oil return operation time in the oil return operation mode. Such a control method may cause the compressor to run without oil, which will lead to increased power consumption, heat generation and component wear of the compressor. It will reduce the service life of the compressor, or even burn the compressor

In addition, the existing air-conditioning system is running in the cooling mode when operating in the oil return operation mode, and the indoor unit is cooling. Lower air temperature, affecting indoor comfort

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