兆瓦级风力发电磁力增速齿轮传动系统的结构设计与性能研究

In order to solve the problem that wind turbine gearboxes break down constantly as impacted by instant stiff wind with irregularly-changing direction and load all year round, it is proposed that a magnetically gearing system using rare-earth permanent magnet be applied. As the existing magnetic gears are gravely low in output power and transmission ratio that the need of megawatt wind turbine gearboxes cannot be met, the method of power split was adopted which can link several field modulated permanent magnetic gears (FMPMG) with high torque density of over 100Nm/m3 together, thus accomplishing the transmission at arbitrarily high power and transmission ratio. In this process we: ①study the characteristic of starting on load for the megawatt permanent gears and its maximum rotary inertia as well as mechanical properties when at stable motion. ② analyse the system transmission structure of power split and the distribution of its transmission ratio, make it sure that the closed power flow cannot emerge and provide the diagram of the relationship between transmission ratio and efficiency. ③build a three-dimensional analytic model of air-gap field and torque which can apply to computer modeling to solve the problem that the end effect is ignored when adopting two-dimensional analytic method or two-dimensional finite element method while the occupation of resources is too high and the cycle of FMPMG's parameter optimization is overly long when using the three-dimensional finite element method. ④give a design theory as well as experiment method of FMPMG that are modular and applicable to power split and with fine dynamics characteristic.

针对风电齿轮箱常年受无规律的变向、变载荷及强阵风瞬时冲击而造成故障率极高的问题，提出采用稀土永磁材料的磁力增速齿轮传动系统。由于现有的永磁齿轮输出功率及传动比均严重偏小，不能满足兆瓦级风电齿轮箱要求，因此本项目采用功率分流方法，将多个转矩密度高达100KNm/m3以上的磁场调制式永磁齿轮级联起来，以实现任意大功率及任意大传动比的永磁齿轮传动系统。在此过程中研究：①兆瓦级永磁齿轮的带载启动特性，并获取其可启动的最大转动惯量及稳定运行时的机械特性；②功率分流时系统的传动结构及其传动比的分配方法，确保不出现封闭功率流，并给出传动比与运行效率的关系图；③建立适于计算机建模的气隙磁场及转矩的三维解析模型，以解决二维解析法或有限元法忽略了磁场的端部效应，而三维有限元法的计算机资源占用率过高且结构参数优化周期较长等问题；④给出模块化、适于功率分流且具有优良动力学特性的磁性齿轮设计理论及实验方法。

针对风电齿轮箱常年受无规律的变向、变载荷及强阵风瞬时冲击而造成故障率极高的问题，提出采用稀土永磁材料的磁力增速齿轮传动系统。. 所提出的级联式结构及功率分流机理，与传统机械行星减速器差动轮系相同，可在较小尺寸空间内将低速大转矩的输入，转换成高速低转矩的输出；根据单级同心式永磁齿轮的运行机理，建立了将其级联起来的传动比及转矩模型，并经理论分析及有限元算例证明了所建模型的正确性；对组成级联式结构的各单级永磁齿轮的转速特性及损耗特性进行了详细分析与研究，给出了减小转速波动的方法。. 优化上述调磁环及永磁体的外形尺寸可有效减小同心式永磁齿轮的铁损及涡损，最末级的同心式永磁齿轮的占空比为1.2且永磁体间距为1.9时，总损耗最小，运行效率最高。. 将永磁电机中的绕组直接与同心式永磁齿轮相复合，可将旋转磁场产生的能量直接送至线圈绕组，以产生所需的感应电动势；分析了上述复合发电机的静态扭矩特性并验证了输入功率的能力；分析了空载及带载启动时的启动特性对发电机绕组的影响；计算了复合发电机在额定转速下的空载电压，分析了其所产生的毛刺现象。. 建立了基于ANSYS环境的上述复合发电机仿真模型，给出了齿槽转矩及电磁参数值的初步确定方法，利用控制变量法对永磁体厚度、气隙厚度、调磁极块厚度及调磁极块占空比等参数与转矩密度的关系进行仿真分析，并对其逐一进行优化；结果表明：优化后的输出转矩较优化前提升了15.1%，而转矩波动幅值则降低了27.5%；优化后的输出转速波幅较优化前降低了35%，表明优化后的各参数值可使复合发电机的性能大幅提高。. 基于上述研究基础，与大连天元电机股份有限公司合作设计并制造出一台传动比为1：40的三级级联式永磁同心式磁齿轮实验样机，并对其进行了转速及转矩实验测试，验证了本项目所提出的级联式同心式永磁齿轮的理论解析与有限元分析方法的正确性。