轴向多段式高速外永磁转子爪极电机的电磁场与温度场分析

Electromagnetic Design and Temperature Field Analysis of a High Speed Claw Motor with Outer Permanent Magnetic Rotor

高速永磁电机可与负载直接相连,省去了传统的机械增速装置,在工业应用与航空航天等领域得到越来越多的应用。传统高速永磁电机采用内转子结构,为避免永磁体受高速旋转带来的拉应力需要采取特殊的保护措施,由此带来永磁体用量大、气隙磁密偏低、涡流损耗严重等突出问题。高速外永磁转子结构电机则可避免上述问题。本文基于一台3k W、20 000r/min的高速外永磁转子爪极电机,对高速外转子爪极电机的电磁方案进行了设计与分析,利用有限元软件验证了电磁设计的合理性;针对高速永磁电机损耗密度大、散热困难等问题,本文设计了轴内水冷系统并建立了三维有限元模型,利用流-固耦合法对电机的温度分布进行了详细分析,最后加工了一台样机,并通过实验验证了本文理论分析的正确性。

High speed permanent magnet motor can connect with the load without any medium and get rid of conventional speed-up gear boxes. Hence, the motor is more extensive used in industrial manufacturing and aerospace equipments recently. Inner punch rotor is widely adopted in conventional high speed permanent magnet motor, and in order to diminish pull stress of permanent magnet, a protection method is often used, which makes permanent magnet volume big, air-gap flux small and eddy-current loss great. But outer rotor high speed permanent magnet motor could avoid the problem. Based on a 3kW, 20 000r/min outer rotor high speed permanent magnet motor, electromagnetic parameters of the motor is designed in this paper, and finite element simulation is used to verify the rationality of electromagnetic design. Aiming at the great loss destiny and difficulty of heat dissipation, a inside-shaft water cooling system is designed and a 3D temperature field model is set up. Two-phase flow method is used to analyze the temperature distribution of the motor in detail. Finally, a prototype is manufactured and the correctness of this paper theoretical analysis is confirmed by prototype test.