Characteristic analysis of the cryogenic permanent magnet synchronous motor for the submerged LNG pump

This paper introduces a submerged LNG (liquefied natural gas) pump cryogenic permanent magnet synchronous motor (PMSM). A 22kW/6000rpm prototype is designed for low temperature operation at −161°C. The influence of temperature on magnetic and electric parameters of materials is analyzed, and a coupled simulation model of electromagnetic-fluid-thermal-stress field is established. On this basis, the motor characteristics such as the loss, back EMF and torque are obtained. The accuracy of the simulation model is verified by the prototype test at −196°C liquid nitrogen. Simulation and test results show that the performance of the cryogenic PMSM is better than that of the traditional motor.