Oil balance system of fluorine system multi-machine parallel unit and control method of oil balance system

The invention relates to an oil balance system of a fluorine system multi-parallel unit and a control method of the oil balance system. The oil balance system comprises two fluorine systems which are connected in parallel. The refrigerant circulating system of each fluorine system comprises a compressor and an oil separator; an inner oil path circulating pipeline is arranged between the compressor and the oil separator of each fluorine system; the two ends of the inner oil way circulation pipeline are connected with an air suction port of the compressor and an oil return port of the oil separator respectively. Two outer oil path circulating pipelines are also arranged between the two sets of fluorine systems; the two ends of the outer oil way circulation pipeline are connected with an air suction port of one compressor and an oil injection port of the other compressor respectively; an inner oil way circulating electromagnetic valve is arranged on the inner oil way circulating pipeline; an outer oil way circul