Design of Cryogenic Permanent Magnet Synchronous Motor for Submerged Liquefied Natural Gas Pump

This paper presents the design of cryogenic permanent magnet synchronous motor (C-PMSM) for submerged liquefied natural gas (LNG) pump. The motor is submerged in LNG with a cryogenic temperature (CT) of −161 °C, and its magnetic and electric characteristics differ greatly from that of the motor at room temperature (RT). So it is necessary to redesign according to the result of conventional design, considering the changes of materials under the cryogenic environment. The operating characteristics of the C-PMSM are investigated, and the redesign method is discussed. Finite-element method is used to analyze the motor performance. A prototype is fabricated and tested to verify the rationality of the design.