高转矩密度的磁场调制型双绕组永磁电机研究

Field-modulated permanent magnet (PM) machines utilize the air-gap effective harmonic fields to realize the high-speed machine design for the armature and ensure the low-speed mechanical speed. Therefore, they are very suitable for electric vehicle direct-drive propulsion and become a hot topic in this area. However, due to the field modulation effect, the air-gap contains abundant harmonic magnetic fields, with only one set of armature winding, the effective harmonic fields can not be fully utilized which reduces the utilization of PM materials and the torque density is not maximized. In order to solve this problem, a dual-winding armature design is proposed for fully utilizing the harmonic fields and machine materials to improve the torque density. The target of this project is to develop a new and appropriate topology for field-modulated dual-winding PM machines, and explore machine design, optimization and analysis methodology for the proposed machine. Dual-winding coordinated control will be studied for improving the torque density and optimizing the machine efficiency. The successful development of the proposed machine will provide a new solution of direct-drive propulsion for electric vehicles. It is not only significant for the scientific research but also has wide application prospects.

磁场调制型永磁电机利用磁场调制所产生的气隙有效谐波磁场同时实现定子电枢的高速设计和保证较低机械转速的运行，满足了电动汽车直驱的需要，成为目前该领域的一个研究热点。然而，由于磁场调制作用，该类电机的气隙磁场包含丰富的谐波磁场，仅采用一个电枢绕组，不但不能充分利用有效的谐波磁场，造成永磁材料利用率低，而且电机的转矩密度因此未得到充分提升。本项目依此为出发点，借鉴双绕组永磁电机的设计思想，使用两套电枢绕组充分利用电机气隙的有效谐波，提高电机材料利用率，提升了电机的转矩密度。本项目旨在开发结构新颖合理的磁场调制型双绕组永磁电机，探索该类电机设计、优化和电磁性能分析的一般方法，并研究双绕组电枢的联调机制，提升转矩密度的同时达到最优的效率。该磁场调制型双绕组永磁电机的研制成功，将为电动汽车用直驱电机提供新的方案。不仅具有重要的学术价值和科学意义，而且具有十分广阔的应用前景。

磁场调制型永磁电机具有高转矩密度和高功率密度等优点，非常适用于直驱的场合，诸如电动汽车驱动、风力发电等。由于磁场的调制作用，该类电机的气隙磁场包含丰富的谐波磁场。如何有效地利用这些谐波磁场成为提高该类转矩密度和效率迫切需要解决的问题。本项目依此为出发点，借鉴同极型电机的拓扑结构，将传统径向磁路的游标永磁电机设计为同极型游标永磁电机，提出一种定子双绕组的具有磁场调制效应的游标永磁电机。根据电机的结构，采用数学建模的方法推导了电机气隙磁密、磁链等数学表达式，并利用三维有限元方法验证了所建立的数学模型，以及计算和分析了其电磁特性。根据数学建模，从理论上分析了该双绕组磁场调制型永磁电电机的工作原理。通过调节具有励磁作用绕组电流的大小和方向，两个绕组的磁通有明显的弱磁和增磁效果，利用这种控制可以很方便地实现转矩增强的目的。根据样机试制和实验验证，证明了所设计的电机拓扑和数学模型的正确性。