泵用直驱永磁同步电机连续运行温升的原因分析

Analysis on the Temperature Rise Causes in Continuous Operation of Direct Drive Permanent Magnet Synchronous Motor

摘要:

南水北调东线某泵站采用的大型贯流泵低速直驱永磁同步电动机为水利行业首次应用，在长时间的运行过程中发现，电机连续运行时会出现机组温度升高、电流增大、损耗增加、效率下降等现象。本文分析了该泵站机组电机永磁体产生可逆退磁的原因，并通过现场实验法对永磁体在连续运行中出现的可逆退磁进行验证，同时从电磁设计、变频器供电和机组冷却三个方面给出了对应的措施，为后续相关大型永磁同步电机的制造和维护提供了经验。

Abstract:

The large-scale cross-flow pump low-speed direct drive permanent magnet synchronous motor used in a pump station of the east line of South-to-North Water Diversion Project is the first application in the water industry.During the long operation, it is found that the unit temperature, the current and the loss increase, while the efficiency decreases when the motor runs continuously. In this paper, the cause of reversible demagnetization of permanent magnet of the unit motor in this pumping station is analyzed, and the reversible demagnetization of permanent magnet in continuous operation is verified by field experiments. At the same time, the corresponding measures are given from the aspects of electromagnetic design, inverter power supply and unit cooling, which provides experience for the subsequent manufacture and maintenance of large permanent magnet synchronous motors.