基于电磁转矩与退磁关联的内嵌式永磁同步电机故障诊断与分析

Interior permanent magnet synchronous motor(IPMSM) has been the key equipment because of its ability of exporting high torque but its speed is low, and other advantages such as high efficiency, high power density and adjustable power factor, etc. Its safety and reliable operation has been the more important initiatives to realize energy conservation. however, during the course of motor running, it is inevitable that the temperature of the inner motor is rising and the sudden ocurrence of the short-circuit faults of the stator winding, thus.caused the demagnetization of permanent magnet(PM), and the performance of IPMSM is lower. Therefore, demagnetization of IPMSM has been the more important bottleneck and becomes the restriction for its safe operation and to maintain its high performance. If we can find the relationship between the electromagnetic torque and demagnetization, and find the quantitative relationship between the.motor parameters and demagnetization field, and electromagnetic torque, it can provide the direct basis and advising for diagnostic of demagnetization faults and the optimization design of IPMSM which the target is to strengthen the ability of anti-demagnetization.Thus, the purpose of this applications is to build the quantitative relationship between the electromagnetic torque and the motor parameters and the demagnetization field, then to strengthen the ability of anti-demagnetization of IPMSM, to guide the safe operation and optimization design of IPMSM, by means of the precise simulation and the experimental determination of demagnetization field, and the precise calculation of electromagnetic torque, then to provide the clear physical picture for safe operation and optimization design of IPMSM.

内嵌式永磁同步电机因为低速状态下能输出大扭矩，同时具有高效率、高功率密度、功率因素可调等优点，成为了高性能伺服驱动系统的关键设备，它的安全可靠运行被视为实现节能减排的重要举措。然而，运行过程中，电机会升温、定子绕组不可避免会发生短路故障，从而造成退磁，使电机性能下降。退磁已成为制约其长时间保持性能及安全应用的重要瓶颈。如能将电磁转矩与退磁关联起来，找出电机参数、退磁磁场及电磁转矩间的量化关系，则能为退磁故障诊断及以抗退磁能力为优化目标的电机优化设计提供直接的依据和指导。本申请项目以“建立电磁转矩、电机参数及退磁磁场间的量化关系，提高内嵌式永磁同步电机抗退磁能力，指导其安全应用及优化设计”为目标，通过退磁磁场的精确模拟仿真与试验测定，电磁转矩的精确计算，建立电磁转矩与退磁磁场间的量化关系，找到影响电机抗退磁能力的关键参数，为内嵌式永磁同步电机的安全应用及优化设计提供清晰的物理图像。

永磁体退磁导致的电机故障严重影响内嵌式永磁同步电机在使用过程中的性能，甚至烧毁电机；项目针对退磁导致的电机故障进行诊断，通过分析退磁磁场与电磁转矩间的关系对永磁体退磁进行诊断并进一步指导内嵌式永磁同步电机的优化设计。首先采用改进型等效磁路法及结合工程计算软件编写电磁计算程序，得出电机基本电磁参数，在此基础上利用ANSYS中的ansoft模块建立电机的二维及三维电机模型，验证电磁方案的合理性；采用基于热网络模型及考虑电机内部各部分损耗的多物理场仿真建立电机的温度场分析模型，分析在病态永磁体情况下电机各部分的局部过热及对电磁转矩的影响；采用二维子域模型并结合麦克斯韦张量法对永磁同步电机的电磁转矩进行精确计算，并对电磁转矩的各部分进行分离；研制100kW样机并精确测量电磁转矩，在改变永磁体组合形式模拟永磁体退磁情况下对电机性能进行测试。结合有限元分析结果及测量结果分析内嵌式永磁同步电机在永磁退磁情况下导致电磁转矩中分量的变化，最终导致电机局部过热而影响电机性能；采用一种新型电机散热结构，在定子轭部开槽放置U型铜管，并根据发热量设置铜管大小及水流量，防止电机局部过热，从而指导电机的优化设计。