大型直驱海上永磁风力发电机电磁场快速计算与电磁-热耦合分析方法研究

The offshore wind power is the development direction of wind power industry in the future and PM wind generator has a great application prospect in this field. Large-scale direct-drive PM embedded salient pole wind generator (PMESPWG) has high power density, good heat dissipating performance and excellent reliability, and it is quite suitable for offshore wind power. In this project, the electromagnetic field fast calculation and electromagnetic-thermal field coupled analysis methods will be studied. In electromagnetic field fast calculation aspect, two rapid and efficient methods are proposed: one is a 3D analytical method based on lumped parameter magnetic circuit, in which a 3D multi-sub-circuit model of the generator is established to instead of the complex magnetic network to obtain the air-gap magnetic field distribution; the other one is the finite element-analytical method, in which by using finite element method only once the magnetic field distributions when the stator and rotor at different relative positions can be obtained. In electromagnetic-thermal coupled analysis aspect, a permeated two-way coupled calculation method is proposed, in which the electromagnetic field’s effect on the thermal source distribution and local heat transfer coefficient and the thermal field’s effect on the permeability and PM working point are all considered to calculate the electromagnetic and thermal field distributions. Based on the calculation results of the coupled method, the optimization work is carried out. A practical PMESPWG prototype is developed based on the optimal results and some correlative experiments are implemented. All the research works are aim at providing theoretical basis and key technique support for the application of large-scale direct-drive PM embedded salient pole wind generator in offshore wind farm.

海上风电是风电事业未来的发展方向，永磁风力发电机在海上风电中具有广阔的发展前景。大型直驱永磁内嵌凸极式风力发电机具有功率密度高、散热好、可靠性高等特点十分适用于海上风电。本课题拟对其电磁场快速计算和电磁-热场耦合分析方法展开研究。在电磁场快速计算方面提出两种计算方法：一种为基于集总参数的解析法，该方法以简单三维多子回路磁路模型代替复杂磁网络计算，可快速获取电机的气隙磁场分布；另一种为有限元-解析计算方法，结合一次有限元计算，便可采用解析计算法获取定转子不同相对位置下的电磁场分布情况。在电磁-热场耦合分析方面，提出渗透式双向耦合计算方法，将电磁场对热源分布和局部传热系数及热场对磁导率及永磁体工作点等的影响实现在电磁场及热场的计算中。最后基于耦合计算结果，对电机进行优化设计并制作样机进行相关试验研究，为大型直驱永磁内嵌凸极式发电机在海上风场的应用提供理论基础和关键技术支撑。

海上风电是风电事业未来的发展方向，永磁风力发电机在海上风电中具有广阔的发展前景。大型直驱永磁内嵌凸极式风力发电机（PMESPWG）功率密度高、散热好、可靠性高，因此十分适用于海上风电。但因其体积、功率及损耗等都比较大，若要获得精确的电磁和热场分布，需要大量的计算，耗时较长，因此对其电磁及热场的快速精确计算方法的研究十分必要。.本项目对大型PMESPWG的电磁场快速计算和电磁-热场耦合分析方法展开研究，包括：1）在电磁场快速计算方面提出了基于集总参数的三维多子回路磁路模型代替复杂磁网络计算，结合冻结磁导率法及等效磁路模型快速获取电机的气隙磁场分布。2）在电磁-热场耦合分析方面，建立了精确的三维电磁-热场耦合模型，将电机的各部分模型精细化建模，将精细模型的各部分损耗对应加载为热源进行热场分析，并将电磁场对局部传热系数及热场对磁导率及永磁体工作点等的影响均考虑在耦合计算中，形成了电磁-热场的双向渗透式耦合计算方法。3）对PMESPWG进行了优化设计，提出了聚磁式直驱永磁内嵌凸极式风力发电机(FI-PMESPWG)，该结构可有效聚合气隙磁场，减少永磁体用量，并增大电机的最大电磁输出功率，减小齿槽转矩。4）进行了部分样机试验，对以上计算及优化方案进行验证。 .以上研究为大型PMESPWG的电磁和热场的快速计算提供了有效的方法，可提高大型直驱永磁电机的初期设计效率，并为瞬态下特别是故障状态瞬态下大型直驱永磁风力发电机的电磁和热性能的准确获取提供了有效解决方案，为其未来的工业应用提供了理论基础和关键技术支撑。