电动汽车动力电机再制造的铁芯电磁性能提升方法及关键技术

Due to the fast development of hybrid vehicle and electric vehicle, as the key component, the production of permanent magnet synchronous motor is in a large quantity. Since the materials in core iron are mainly imported and expensive, it has a big potential to be remanufactured. Moreover, with the rising standards and various influence factors for the performance of motors, motor remanufacturing is so difficulty that less study has been found in domestic and foreign. In this project, several key issues for iron core performance improvement in electric vehicle motor remanufacturing are studied. With establishing the separation mechanism of the surface isolation in core iron, the high efficient method of separating surface isolation is presented. Informed by the magnetic influence mechanism caused by bending deformation and the calculation of core iron loss, the re-design method for iron core is given to improve magnetic of silicon steel sheet. Based on the overlying experiments of mixing materials with remanufactured silicon steel sheet and soft magnetic materials, the performance calculating model and design method of mixing iron core is established. Thus, insulation aging caused by the long servicing time, deteriorating magnetic caused by bending deformation, the imperfect structural design and the mixing magnetic materials could be solved. And the above models, methods and technologies could be the foundation support to reduce the iron loss, improve the efficiency, power density and reliability in permanent magnet synchronous motor and could be widely applied in industry.

我国纯电动及混合动力汽车发展迅猛，永磁同步电机作为电驱动系统的核心部件，不仅量大面广，且铁芯材料主要依赖进口、价格昂贵，再制造潜力巨大；此外，其性能标准不断提升、电磁性能影响因素众多等使得再制造难度大，国内外相关研究较少。本项目针对电动汽车永磁同步电机铁芯再制造关键问题展开研究。研究铁芯材料表面绝缘层剥离机理，提出绝缘层高效剥离方法；研究弯曲形变的磁性能影响机制、铁芯损耗计算，提出硅钢片磁性能提升和基于铁芯损耗模型的铁芯再设计方法；通过再制造硅钢片与新型软磁材料组合材料混合叠压铁芯试验、分析与计算研究,建立混合铁芯电磁性能计算模型，提出混合铁芯设计方法。解决电机铁芯长期服役造成绝缘老化、弯曲形变使磁性能恶化、结构设计不完善、组合材料铁芯性能优化问题。上述模型、方法及技术能为电动汽车用永磁同步电机铁芯损耗抑制及再制造电机效率、功率密度、可靠性的提升提供基础支持,具有广阔的应用前景。

随着电动汽车的快速发展，每年会有大量动力电机退役，作为电动汽车的主流动力电机，退役永磁同步电机价值高，再制造价值大。项目对此进行了研究，取得了一些阶段性成果。.1. 提出了将定子铁芯更换为由非晶合金和硅钢叠压形成的混合定子铁芯，留用转子、机壳等零部件，进行退役永磁电机再制造的方法。研究了定子混合方式对再制造电机性能的影响，得到了非晶合金比例对再制造电机性能的影响规律，给出了非晶合金的最优比例及二种材料的组合方式。2.发现了异质材料混合叠压铁芯的气隙磁场偏向现象，揭示了气隙磁场偏向机制，研究了气隙磁场偏向对电机动平衡及温度的影响。3. 应用磁路分析法，建立了考虑定子部分磁阻的电机磁路模型，提出了异质材料混合叠压铁芯气隙磁密的计算方法，得到了混合叠加电机气隙磁密计算公式。4. 建立了再制造电机模型，分析了混合定子铁芯对再制造电机的输出转矩、铁芯损耗、三维温度场、齿槽转矩等性能参数的影响。5. 提出了转子外圆优化、转子偏心再设计和组合偏心槽的转子再设计等铁芯再设计方法，综合优化了再制造永磁电机的齿槽转矩、转矩脉动、损耗等性能参数，有效地提升了电机的综合性能。6. 研究了铁芯硅钢片绝缘涂层的老化行为和剥离机理，发现热老化在绝缘涂层老化和涂层附着性方面起主要作用，而电老化的影响有限。确定了涂层/基体界面的附着形式为物理附着，涂层的剥离是一种物理过程，揭示了应力对硅钢片涂层剥离效果的影响规律，提出了硅钢片绝缘涂层高效剥离方法，提升了废旧硅钢再利用效率与价值。7. 采用实验/试验和软磁交/直流测试仪、Bitter粉纹法等多种分析手段，研究了弯曲变形对硅钢片磁性能的影响机制。8.深入研究了冷轧和斜轧工艺对硅钢片磁畴形貌和织构演变的影响，探索了旧硅钢片磁性能的提升方法。.以上研究成果，为电动汽车用永磁电机的高效再制造提供了基础支持。同时，异质材料混合叠压铁芯技术，极大地拓展了电机制造和再制造思路，对电机产业的发展具有广泛的意义。