基于精确子域模型的游标永磁电机解析磁场计算

Analytical Magnetic Field Calculation of Vernier Permanent-magnet Machines Based on Accurate Subdomain Model

游标永磁电机是一种基于磁场调制原理的新型电磁传动装置,适用于船舶推进、风力发电等低速大转矩的应用场合。准确计算游标永磁电机的磁场分布是设计、优化电磁性能的关键。关于电机解析磁场计算,该文讨论和比较了一极一槽模型和精确子域模型。以表贴式游标永磁电机为研究对象,在气隙子域建立拉普拉斯方程,在槽子域和永磁体子域建立泊松方程,根据分离变量法直接求解。模型建立在二维极坐标下,考虑了径向/平行/Halbach充磁,单层/双层绕组分布,内/外永磁转子结构,可计算电机空载磁场、电枢磁场和负载磁场分布。在解析模型的基础上,求解了气隙磁密分布、空载反电势和绕组电感,相关有限元结果验证了解析结果的准确性。

Vernier permanent-magnet machines are novel magnetic force transmission devices, and are becoming promising candidate for low-speed high-torque applications such as ship propulsion and wind power generation. Accurate calculation of the magnetic field is a key to design and optimize vernier permanent-magnet machines. The one slot per pole machine model and the accurate subdomain model are discussed and compared. The Laplace＇s equations in the airgap subdomain, Poisson＇s equations in the permanent magnet subdomain and the slot subdomain are solved by the variable separation method. The analytical model is set up in 2D polar coordinates and accounts for the influence of radial/parallel/Halbach magnetization, single/double layer winding configurations, internal/external rotor topologies, which can be used to predict the open-circuit, armature reaction and on-load magnetic field distribution. Based on this field model, the electromagnetic performances, such as the airgap magnetic field density, back-EMF and winding inductances is calculated. The analytical model is validated by the corresponding finite-element results.