Magnetic levitation motor sealing-cooling apparatus for refrigeration system and method therefor

A cooling method for a magnetic levitation motor sealing-cooling apparatus for a refrigeration system that comprises a magnetic levitation first-stage compressor, a magnetic levitation second-stage compressor, a magnetic levitation expander, a main heat exchanger, and a cooling gas regulating valve, the magnetic levitation first-stage compressor and the magnetic levitation expander being coaxially arranged, and the magnetic levitation first-stage compressor, the magnetic levitation second-stage compressor, the magnetic levitation expander, and the main heat exchanger being sequentially connected, wherein cooling gas in a magnetic levitation motor cavity of the magnetic levitation second-stage compressor is taken from a working medium cooled at an outlet of the magnetic levitation first-stage compressor;

• cooling gas of a magnetic levitation motor cavity of the magnetic levitation first-stage compressor is taken from cooling gas at an outlet of the magnetic levitation motor cavity of the magnetic levitation second-stage compressor, and by adjusting a flow rate and pressure through the cooling gas regulating valve, a part of the working medium cooled at the outlet of the magnetic levitation first-stage compressor is led, as cooling gas, into the magnetic levitation motor cavity of the magnetic levitation second-stage compressor through conduits for cooling a magnetic levitation motor of the magnetic levitation second-stage compressor;
• a part of cooling gas downstream of the outlet of the magnetic levitation motor cavity of the magnetic levitation second-stage compressor is led into the magnetic levitation motor cavity of the magnetic levitation first-stage compressor for cooling a magnetic levitation motor of the magnetic levitation first-stage compressor, and the remaining part of the cooling gas is led into upstream conduits of a working medium inlet of the magnetic levitation first-stage compressor and re-enters the magnetic levitation first-stage compressor for circulation;
• and cooling gas downstream of an outlet of the magnetic levitation motor cavity of the magnetic levitation first-stage compressor is led into the upstream conduits of the working medium inlet of the magnetic levitation first-stage compressor and re-enters the magnetic levitation first-stage compressor for circulation.