深冷永磁同步电机设计基础理论与技术问题研究

Cryogenic motor technology is one of key technologies in cryogenic applications including the liquefied natural gas (LNG) submeged pump application. The cryogenic motor will be submerged and running in LNG etc. under the temperature below -161.5℃. At present, there are only a few researches about cryogenic permanent magnet synchronous machines carried on, and there are still lots of key basic technical problems remain unsolved, or lacking of precise cryogenic characteristic and mechanism interpretation in depth..Based on cryogenic permanent magnet synchronous motor prototypes already seveloped, this project intents to carry on researches on basic science and technology issues of cryogenic permanent magnet synchronous motor design, including the researches about the cryogenic electromagnetic properties and mechanical properties of stator silicon steel core material; the cryogenic telectromagnetic properties and mechanical properties of permanent magnetic materials and their application technologies in cryogenic permanent magnet machine; the cryogenic eddy current loss and additional high frequency losses characteristics and calculcations; the permanent magnet rotor structure and fluid viscous friction loss analysis. By solving these key basic issues, the project tries to form a systemfied design and analysis technology for cryogenic permanent magnet motor, and also to lay a science and technology foundation for other cryogenic machine technologies.

深冷电机是液化天然气潜液泵等超低温应用中的关键技术之一，运行于温度-161.5℃以下的液化天然气等深冷温度条件。目前关于深冷永磁同步电机的研究开展较少、技术薄弱、许多关键技术问题尚缺乏准确规律研究及深层次机理解释。.本项目在已研制的深冷永磁同步电机样机基础上，针对深冷永磁同步电机设计的基础理论及技术问题展开研究，包括定子铁心硅钢片材料的在深冷温度下的电磁性能与力学性能研究、永磁材料在深冷温度下的电磁性能与力学性能及其在深冷永磁电机中的应用技术、深冷永磁同步电机中涡流损耗及高频附加损耗等机理分析与准确计算、深冷永磁同步电机的转子结构与液体粘滞摩擦损耗分析等关键技术问题。通过对这些低温电机设计基础问题的研究，建立起深冷永磁电机设计与分析的理论与技术体系，为类似深冷电机的研究和应用奠定理论与技术基础。

由于在深冷温度下许多电机材料特性及参数变化规律与一般低温范围下的情况有较大差异，从而导致电机运行情况及特性有较大差异，造成了电机设计及制造的特殊性。目前关于深冷电机铁心材料在低温条件下的电磁性能研究结果尚存在较大差异，从而导致定子铁心硅钢片材料的在深冷温度下的损耗性能计算以及深冷电机中高频涡流损耗及附加损耗计算无法准确进行，而铁心材料的磁性能与损耗计算是深冷电机设计中的关键技术，也是本项目的主要研究内容。比较铁心磁性能与损耗性能的常温与低温实验数据，主要结论包括：硅钢片内达到相同磁感应强度时，深冷温度下所需磁场强度需增加40~70%左右，与励磁频率有关；硅钢片内达到相同磁感应强度时，深冷温度下的铁心损耗增加40%左右。与之相对应，在深冷永磁电机设计技术中，深冷电机磁路工作点与铁心损耗及损耗涡流系数可以相应确定，同时永磁磁负荷工作点改变及励磁电流增加所导致铜损计算与常规电机设计技术均有不同。