大型永磁风力发电机整体充磁系统设计及应用

Design and Application of the Post Assembly Magnetization System for Large Permanent Magnet Wind Generators

在传统的大型永磁电机磁极制造过程中,采用的“先充磁后组装”预充磁技术存在生产效率低、安全风险大等问题。为此,该文提出一种大型永磁风力发电机整体充磁技术,将传统的“先充磁后组装”改为“先组装后充磁”,有效地提高了装配精度、生产效率和安全性。首先通过研究N46SH钕铁硼永磁材料在多角度外磁场中的磁化及退磁行为,获得其在不同磁场方向下的饱和磁化判据;然后针对MW级直驱和半直驱风力发电机结构,提出其整体充磁系统中充磁线圈的设计方法,重点阐述充磁线圈的电-磁-热-力分析;最后以在2.5 MW直驱和20 MW半直驱风力发电机的整体充磁应用为例,研制了充磁线圈及其冷却系统、充磁电源、旋转推进系统和测量控制系统,成功应用于湘电和中车等企业的MW级系列永磁风力发电机的制造与维护,该文设计方法的可靠性得到有效验证。

In the conventional manufacturing process of large permanent magnet motors,the prevalent“magnetize then assemble”pre-magnetized technique is fraught with challenges such as low production efficiency and significant safety risks.Addressing these issues,this research introduces an innovative postassembly magnetization method for large permanent magnet wind turbine generators.This method revolutionizes the traditional approach by advocating for“assemble then magnetize”,substantially enhancing assembly accuracy,production efficiency,and safety.This research initially focused on the magnetization and demagnetization behaviors of N46SH neodymium-iron-boron(NdFeB)permanent magnet materials under various external magnetic field orientations.It established criteria for deter mining the saturation magnetization strength in different magnetic field directions,laying the foundation for subsequent magnetizing coil design.For megawatt-level direct-drive and half-dirve wind turbine generators,a comprehensive design method was proposed for magnetizing coil systems within the post-assembly magnetization system.This involved an in-depth electromagnetic,thermal,and mechanical analysis of the magnetizing coils,with a particular emphasis on addressing the eddy current issues during magnetization,calculations of the coil cooling process,and stress distribution within the coils.The study further introduced case studies of post-assembly magnetization applications in 2.5 MW direct-drive and 20 MW half-drive wind turbine generators,encompassing the design and functionality of magnetizing coils,cooling systems,magnetizing power sources,rotational and propulsion systems,and measurement and control systems.The application of the proposed method in the manufacturing and maintenance processes of megawatt-scale permanent magnet wind turbines generators was illustrated,especially in its adoption by industry leaders such as Xiangdian Electric Manufacturing Company Limited(XEMC)and China Railway Rolling Stock Corporation(CRRC).The stability and reliability of the magnetizing coils were validated through continuous discharge experiments.Furthermore,a comprehensive comparative analysis was conducted between post-assembly magnetized motors and pre-magnetized motors,encompassing various aspects such as magnetic pole performance and overall motor performance.The results indicated that post-assembly magnetized motors not only met all performance standards but also exhibited superior pole consistency and manufacturing efficiency.This outcome is particularly crucial for an industry increasingly focused on reliability and efficiency.Additionally,the research extended the post-assembly magnetization technique to the maintenance and recycling of damaged or retired permanent magnet motors.This application achieved complete demagnetization of the poles,reducing the demagnetization time by five orders of magnitude compared to traditional methods,and was environmentally friendly,resulting in zero pollution and promoting sustainable and green remanufacturing of permanent magnet motors.In conclusion,the reliability of the proposed post-assembly magnetization design method was validated through comprehensive testing and analysis.This validation emphasized the technical feasibility and practical applicability of the method in the current industrial environment.The findings of this study have the potential to revolutionize the manufacturing processes and design of large permanent magnet motors,especially in the field of wind energy,by introducing a more efficient,safe,and environmentally friendly post-assembly magnetization technique.