调焦系统高转矩密度盘式直驱永磁游标电机研究

In order to solve the problems of the low electromagnetic torque, low efficiency in the drive motor of the large-load focusing system, a disk-type direct-drive permanent magnet vernier motor (DDPMVM) is investigated based on the proper install structure cooperation between the motor and the lens barrel shell, as well as the inherent magnetic field modulation feature in the vernier motor. The proposed DDPMVM is presented to suit the requirement of the focusing system drive motor, such as the high torque density, low vibration, low ripple, precision control and so on. Since the DDPMVM adopts the surface ring-type magnets, the leakage flux and losses are reduced, which contributes to increase the motor lifetime and relatively reduce the material price. Due to the usage of axial symmetrical shifted stators and multi-layer interior permanent magnets, DDPMVM can improve the usage of magnetic flux circuit, efficiency and overcome the problems of axial electromagnetic force and operation noise for the high-accuracy focusing system application. In this research, the DDPMVMs are taken into consideration for the application of the lens drive system with long focal lengths. The design and operation principle of their magnetic field modulation, the analytical model, the analysis of motor steady and dynamic performance, the multi-objective function optimal design as well as the control strategy are discussed in detail. By this way, more and more electric motors like the DDPMVM can be further developed, as well, the theoretical and technique supports can be built to contribute to the high-performance focusing system application with long focal length and large load.

针对长焦大负载调焦系统中驱动电机转矩小、效率低等问题，项目从直接安装在调焦部件上的盘式电机结构出发，基于游标电机的磁场调制特性提出了无需变速装置的直驱盘式永磁游标电机模型，以满足调焦系统驱动所需的转矩密度大、脉动小、可精密调控等要求。首先，采用表贴式环形永磁体的初级盘式游标电机结构可以有效减小漏磁，降低损耗，具有使用寿命长和材料造价低的优点；而且采用轴向对称交错定子和内置式永磁体的多层模块化盘式游标电机结构可以有效提高磁路利用率和磁场强度，兼有克制轴向电磁力偏移和运行噪声的优点，应用于精密调焦系统优势明显。本项目以此盘式直驱永磁游标电机为研究对象，结合长焦大负载调焦系统的特殊工况需求，拟对其基本磁场调制原理、等效解析模型、稳态和动态性能分析、多目标优化方案及控制策略进行系统深入研究，探索该类电机应用于调焦系统的一般规律，为实现其高性能驱动提供可靠的理论基础和技术支持。

本项目以此盘式直驱永磁游标电机为研究对象，结合长焦大负载调焦系统的特殊工况需求和安装位置限制，对其基本磁场调制原理、等效解析模型、性能优化方案及制造测试进行系统深入研究，探索该类电机应用于调焦系统的一般规律，为实现其高性能驱动提供可靠的理论基础和技术支持。. 主要完成工作包括：结合镜头驱动型电机特殊的安装位置和尺寸需求，设计了具有体积小，低速高转矩，振动噪声小等特性，且综合考虑电机转矩和能量传输效率特性的电磁式电机结构；基于盘式直驱永磁游标电机的磁场调制机理，建立了电机的等效磁场解析分析模型和有限元仿真模型，计算得到了电机主要电磁特性并进行对比验证精确度；在保证盘式直驱永磁游标电机的可靠运行前提下，建立以最大化电磁转矩密度，最小化齿槽转矩和转矩脉动为电机优化设计的基本优化目标，完善科学标准化的优化流程和优化策略；制造一款额定转速50rpm，额定转矩68mNm原理样机并搭建电机性能测试平台，完成对样机稳态性能的基本测试，以验证所述理论的可行性和设计的合理性。依托该项目研究，发表了相关学术论文5篇，其中SCI收录4篇，授权国家发明专利4项，培养研究生3名。