摘要
对于采用低电导率护套高电导率永磁体的表贴式高速永磁电机,在永磁体和保护套之间增加一层低电导率的永磁体,可有效降低永磁体上的涡流损耗。目前,对于双层永磁体转子结构的电机在使用有限元软件进行转子涡流损耗计算时,因为需要寻求两种永磁体不同厚度配比下的最优方案,所以要进行大量参数化,导致计算时间长、效率低。针对这一问题,该文基于精确子域法,建立了一个考虑定子开槽以及涡流反作用影响的双层永磁体结构转子涡流损耗解析模型,可同时对电枢磁场和负载磁场下双层永磁体结构转子涡流损耗进行求解,并且该模型可扩展至多层永磁体复合结构的转子涡流损耗计算。在此基础上分析了双层永磁体结构下外层永磁体不同厚度和不同材料对转子涡流损耗和内层永磁体消耗量的影响。最后通过有限元仿真和C型铁心实验验证了该解析模型的有效性。
High-speed permanent magnet motor(HSPMM)has the advantages of high efficiency,fast dynamic response,etc.and is widely used in the field of high motor performance requirements.Due to the poor heat dissipation condition of surface-mounted HSPMM,the permanent magnet(PM)will face the risk of irreversible demagnetization if the eddy current loss on the rotor retaining sleeve and PMs is high.The eddy current loss of the double-layer permanent magnet(DLPM)rotor structure can be effectively restrained by using the PM with high resistivity in the outer layer.However,the calculation time of eddy current loss of the rotor in different ratio of the structure by finite element software is long,which is not conducive to the initial design and optimization of the motor.Based on the exact subdomain method,an analytical model of rotor eddy current loss of DLPM structure is established,which can shorten the calculation time of rotor eddy current loss.The research idea of this paper is as follows Firstly,the motor is divided into 7 subdomains,such as outer permanent magnet subdomain,inner permanent magnet subdomain,retaining sleeve subdomain,etc.Laplacian equation and diffusion equation are written for different subdomains,and the general solution of vector magnetic potential in each subdomain is obtained according to the continuous boundary conditions of vector magnetic potential and tangential magnetic field strength as well as the ferromagnetic boundary conditions of each subdomain.Then the eddy current losses in different subdomains are obtained by Poynting theorem.Secondly,a two-dimensional finite element model is established to compare the air gap flux density obtained by the analytical model and the rotor eddy current loss.The deviation between the analytical model and the finite element is within the allowable range of engineering and meets the accuracy requirements.Finally,the analytical model is verified by the C-type core loss experiment,and the analytical calculation results are compared with the finite element and C-type core experiment results,and the error is less than 5%,which further verifies the accuracy of the analytical model.In addition,the influence of different material and thickness of outer PM on eddy current loss and magnetic steel cost of HSPMM is investigated by using analytical model.Taking the motor studied in this paper as an example,when the magnetic density of the air gap is unchanged,the outer permanent magnet is bonded NdFeB or Ferrite with the same thickness,and the inhibition effect on eddy current loss of the rotor is similar,but when the bonded NdFeB with strong magnetic properties is used,the amount of sintered NdFeB in the inner layer is reduced by about 20%Therefore,for the DLPM rotor structure,the thickness and material of the outer permanent magnet should be determined by weighing the reduction of eddy current loss of the rotor and the amount of the inner permanent magnet.
作者
佟文明
杨先凯
鹿吉文
贾建国
李文东
Tong Wenming;Yang Xiankai;Lu Jiwen;Jia Jianguo;Li Weidong(National Engineering Research Center for Rare-Earth Permanent Magnet Machines Shenyang University of Technology,Shenyang 110870,China;Shenyang Micro Control New Energy Technology Co.Ltd,Shenyang 110178,China)
出处
《电工技术学报》
EI
CSCD
北大核心
2024年第20期6293-6304,共12页
Transactions of China Electrotechnical Society
基金
国家自然科学基金(52222702)
辽宁省“兴辽英才计划”(XLYC2007107)
沈阳市创新人才工程(RC210067)资助项目。
关键词
双层永磁体
高速永磁电机
精确子域模型
C型铁心实验
Double layer permanent magnet
high speed permanent magnet motor
accurate subdomain model
C-shape core experiment
