Subjects: Dynamic and Electric Engineering >> Electrical Engineering submitted time 2019-03-05 Cooperative journals: 《电气工程学报》
Abstract:不均匀气隙结构的异步起动永磁体同步电机是针对普通异步起动永磁同步 电机由于气隙磁场谐波复杂而导致的运行过程中转矩脉动大、电磁噪声高等问题提出 的,此结构电机的永磁体退磁情况与普通电机有较大不同。本文基于永磁体内各处的 磁场矢量基本相同的原则,利用永磁体内部一点的磁密表征整个永磁体在运行过程中 磁密的变化,对不均匀气隙结构异步起动永磁体同步电机永磁体工作点展开了理论研 究与有限元仿真。分析了影响电机退磁的因素,研究了施加不同负载与转动惯量时永 磁体的磁密变化情况,得到电机稳态运行时和起动过程中永磁体工作点的变化规律, 提出了获得永磁体磁密最小工作点的研究方法。
Subjects: Dynamic and Electric Engineering >> Electrical Engineering submitted time 2019-03-05 Cooperative journals: 《电气工程学报》
Abstract:针对永磁电机的齿槽转矩影响其控制精度和性能的问题,本文提出削角可 以有效抑制齿槽转矩的方案。以一台 30 槽 10 极永磁电机为例,利用数值仿真原理, 建立电机电磁场有限元模型,对削角削弱齿槽转矩的方法进行仿真分析。研究表明, 齿槽转矩的大小与削角高度和削角宽度有关,选取合适的削角高度和宽度可以有效地 削弱齿槽转矩。仿真结果证明了本文基于削角的齿槽转矩削弱方法的有效性和正确性。
Subjects: Dynamic and Electric Engineering >> Electrical Engineering submitted time 2019-03-05 Cooperative journals: 《电气工程学报》
Abstract:超导托克马克聚变实验装置(EAST)的极向场超导线圈发生失超时,超导 线圈电阻变化引起的微弱电压信号变化被强噪声淹没。针对该问题,运用快速傅里叶 变化分析线圈电压信号的时频特性。根据分析结果,提出运用经验模态分解(EMD) 方法对超导线圈两端电压信号进行分析,得到若干固有模态分量和余项,并得知微弱 信号的能量主要分布在余项中。该方法能够消除环境影响,检测出电压信号的微弱变 化。
Subjects: Dynamic and Electric Engineering >> Electrical Engineering submitted time 2019-03-05 Cooperative journals: 《电气工程学报》
Abstract:不均匀气隙结构的异步起动永磁体同步电机是针对普通异步起动永磁同步 电机由于气隙磁场谐波复杂而导致的运行过程中转矩脉动大、电磁噪声高等问题提出 的,此结构电机的永磁体退磁情况与普通电机有较大不同。本文基于永磁体内各处的 磁场矢量基本相同的原则,利用永磁体内部一点的磁密表征整个永磁体在运行过程中 磁密的变化,对不均匀气隙结构异步起动永磁体同步电机永磁体工作点展开了理论研 究与有限元仿真。分析了影响电机退磁的因素,研究了施加不同负载与转动惯量时永 磁体的磁密变化情况,得到电机稳态运行时和起动过程中永磁体工作点的变化规律, 提出了获得永磁体磁密最小工作点的研究方法。
Subjects: Dynamic and Electric Engineering >> Electrical Engineering submitted time 2019-03-05 Cooperative journals: 《电气工程学报》
Abstract:多逆变器并联运行时,由于各逆变器的设计参数、连线阻抗等都存在差异, 各逆变器模块的等效线路阻抗也各不相同,往往会产生系统环流,导致系统不稳定。 本文将对逆变器并联运行系统进行分析,并且提出一种基于虚拟阻抗的逆变器并联运 行环流抑制方法。
Subjects: Dynamic and Electric Engineering >> Electrical Engineering submitted time 2019-03-05 Cooperative journals: 《电气工程学报》
Abstract:有限元方法精度很高,适合求解复杂结构的电机磁场问题。运用三维有限 元方法,比较分析了径向磁化、平行磁化两种磁化方向以及有齿尖及无齿尖两种结构 永磁屏蔽电机的空载磁场参数。在此基础上,分析了齿尖平均弧长、齿尖厚度和外侧 倾斜角等齿尖结构参数对两种磁化方向电机空载磁场参数的影响。计算结果表明,对 于两种磁化方向,有齿尖结构永磁屏蔽电机的空载气隙磁通密度基波幅值、THD 以及 齿槽转矩都较大,而感应电动势较小。
Subjects: Dynamic and Electric Engineering >> Electrical Engineering submitted time 2019-03-05 Cooperative journals: 《电气工程学报》
Abstract:模块化多电平变流器(MMC)具有大量子模块,控制结构系统复杂度和成 本均大为增加,且传统的 CAN 通信或 RS 485 通信传输速率较慢,可靠性较低,导致 各子模块之间信号同步性较差,难以满足多个控制器之间协调运行及高速可靠的通信 要求。针对这一问题,本文引入 EtherCAT 工业以太网技术,提出一种基于 EtherCAT 的模块化多电平变流器的控制器架构方案。相比于传统分层控制方案,该方案仅包括 主站控制器和从站控制器两层,简化了控制结构,而且极大地提高了主从站间的传输 速率及可靠性,同时该方案可以精确地保证控制器间的载波信号同步。基于该方案搭 建了三相 MMC 实验平台,实验结果表明了该方案的可行性与正确性。
Subjects: Mechanical Engineering >> Other Disciplines of Mechanical Engineering submitted time 2018-06-15 Cooperative journals: 《电气工程学报》
Abstract: In experimental advanced superconducting Tokamak (EAST) device, during the quench process of a superconducting coil, the voltage variation caused by change in coil resistance is so small that is submersed in the background noise. To solve the problem, the time-frequency characteristic of the coil voltage signals is analyzed by Fourier decomposition, then the coil voltage signals is decomposed into several intrinsic mode functions (IMF) and the remainder by empirical mode decomposition (EMD). The result shows that the energy of weak signal is distributed mainly in the remainder and the weak variation can be extracted from the noise by EMD.
Subjects: Mechanical Engineering >> Other Disciplines of Mechanical Engineering submitted time 2018-06-15 Cooperative journals: 《电气工程学报》
Abstract: Line-start permanent magnet synchronous motor (LSPMSM) with nonuniform air gap structure is proposed for reducing torque ripple, high electromagnetic noise caused by the complex harmonic distortion rate of air gap magnetic field of common LSPMSM. The demagnetization condition of the permanent magnet of the structure is different from that of the ordinary motor. In this paper, based on the principle that magnetic field vector in permanent magnet is almost the same, the magnetic flux density of the permanent magnet is characterized by the magnetic density of inner point of the magnet. Theoretical study and finite element simulation of line-start permanent magnet synchronous motor with non-uniform air gap structure are carried out. This article has analyzed the influence factors of the motor demagnetization, and relationship between load characteristic and demagnetization of permanent magnet has also been studied. In this paper, the variation law of permanent magnet working point during steady state operation and starting process is obtained, and research method of obtaining the minimum working point of permanent magnet is proposed.