A variable frequency magnetic suspension compressional expansion
assembly comprises a compressor, an
evaporator and an expansion
machine that are connected. A magnetic suspension bearing
centrifugal compressor is directly connected with a radial flow type expansion
machine via a shaft, the shaft is suspended on a left radial magnetic suspension bearing, a right radial magnetic suspension bearing and an axial magnetic suspension bearing, a variable frequency motor is provided between the left radial magnetic suspension bearing and the right radial magnetic suspension bearing and used for driving the
centrifugal compressor; and the radial flow type expansion
machine comprises an air inlet chamber and an air outlet
pipe, nozzles and impellers are provided between the air inlet chamber and air outlet
pipe and passed through the air inlet chamber and air outlet
pipe, and the impellers are fixedly connected on the shaft. The power from expansion is transmitted to the compressor, and the
refrigerant after expansion is entered into the
evaporator to carry out evaporative cooling; after being evaporated in the
evaporator, the
refrigerant is sucked by the compressor to carry out circulatory flow; and the magnetic suspension bearings assure that the shaft does not contact with the bearings when the
assembly operates, so that
lubrication via lubricating oil is not needed.