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.