PWM供电下横向磁通永磁电机电磁噪声的分析及抑制研究

Electromagnetic noise is an important technical index for electric motor and the noise level of electric motor has become an essential factor in market competition. Electromagnetic noise of motor involves multidisciplinary knowledge, such as electric machinery, acoustics, structural dynamics and signal analysis, which led to the complexity and difficulty of noise problem. To solve the problem fundamentally, we should take steps to suppression noise in design stage. Transverse flux permanent magnet motor has high torque density and efficiency, which attracts more and more researchers and businesses. So, study on electromagnetic noise is particularly important for it. The project takes the method of combination of optimize design theory and control to analyze and control electromagnetic noise for transverse flux motor. First, design motor with low electromagnetic noise by the simulation and theoretical analysis. In addition, introduce wavelet theory to noise source identification technology. To get clear signal characteristics, the further frequency spectrum of reconstructive signals would be analyzed. Then suppress electromagnetic noise in accordance with specific harmonic waves. In the final step, the suppression of electromagnetic noise would be studied by using dual randomized PWM based on Markov chains. This project has important implications for the development of economy, science and technology, and application of this type of motor in the correlative field.

“噪声”是电动机主要技术指标之一，更是电动机品质指标和优等价格的重要依据。电动机的噪声涉及电动机、声学、结构动力学、信号分析等专业学科，造成噪声问题的复杂性和高难度。在电动机电磁设计阶段即控制电磁噪声是从根本上实现噪声控制的方法。横向磁通永磁电机同时具有高转矩密度及高效率的特点，已经引起电机研究者与商家关注，对该类电机噪声控制研究也显得尤为重要。本项目针对横向磁通永磁电机，采取电机本体优化设计和控制相结合的方法分析和抑制电磁噪声。首先经过仿真及理论分析设计低噪声横向磁通永磁电机；其次将小波理论引入噪声源识别技术，对频率范围在所需范围重构信号进行2次频谱分析，清晰得出信号特征，并结合特定谐波消除PWM对电磁噪声进行控制；最后针对基于Markov链的双随机PWM方法进一步研究该类电机电磁噪声抑制问题。该项研究对促进科技、社会的发展，及推进该类电机在相关领域的应用均具有重要意义。

电机噪声危害人类身心健康，缩短电机使用寿命，一些特殊使用场合更是对电机振动噪声有严苛的标准，振动噪声水平作为衡量电机性能的重要指标之一，正在受到越来越多的重视。根据噪声产生机理，电机噪声可分为机械噪声、空气动力噪声、电磁噪声三类。在这三类噪声中，机械噪声由电机的加工精度、装配质量等决定；空气动力噪声主要从风扇和风路设计方面抑制；电磁噪声来自电磁力引起的振动。近些年，随着大功率电气传动技术的发展，人们迫切需求具有高转矩密度、适用于低速、大转矩直接驱动的电机，横向磁通永磁电机因满足这些要求成为研究热点。本项目研究内容为一台20kW横向磁通永磁电机，该电机为聚磁式结构，三相圆周排列，定子采用双边结构。项目采用解析及有限元相结合的方法，分别针对正弦电源及PWM供电情况，通过对电机定子系统固有频率、作用于定子系统电磁力及电机在电磁力作用下的振动响应进行分析和计算，获得电磁噪声；同时分析电磁噪声产生的原因，找到引起电磁噪声的来源，得到该类电机的电磁振动特性，为有针对性的抑制该类电机噪声奠定了工作基础，对工程应用有一定参考价值。在项目的进行阶段，团队成员共发表论文近10篇，获取发明专利一项，实用新型专利一项，培养硕士研究生2人，参加国际会议两次。