双凸极永磁电机新型控制策略研究

在对双凸极永磁电机数学模型和静态参数分析的基础上,该文分析了其转矩脉动的产生原因。针对常规转速电流双闭环控制策略转矩脉动大的缺点,提出了一种新型转速转矩电流三闭环控制策略。基于Matlab/Simulink搭建了电机和控制器模型,仿真结果表明了控制策略的正确性和有效性。     

一种新型双凸极单相永磁电动机的工作原理与参数计算

介绍了１种双凸极单相永磁电动机。电机有４个定子极和６个转子极,转子上无绕组及永磁体,定子上放置绕组和永磁体。定子极采用阶梯形结构,使电机可以起动。电机结构控制简单,可双向运转,适合于调速控制系统。研究了该电机的工作原理及其参数的计算,为电机的控制及系统仿真奠定了基础并提供了依据。     

纳滤膜过滤多组分离子电解质溶液的模型与计算——Ⅰ理论模型

以固定电荷模型为基础,采用扩展的Nernst-Planck方程结合Gouy-Chapman(GC)理论和Donnan平衡模型,通过一系列假设和推导,得到多组分离子溶液透过纳滤膜时离子浓度在膜微孔内梯度微分方程和解膜微孔内梯度微分方程的有关参数和方程。     

双凸极永磁电机斜极转子设计和绕组换流模式研究

本文首先分析了双凸极永磁电机转子极弧宽度对自定位转矩的影响,提出了双凸极永磁电机等极弧半极宽斜极转子的设计思想;在此基础上,通过对绕组磁链的分析,率先将六状态换流模式引入到双凸极永磁电机的控制系统中,改善了双凸极永磁电机的换流特性,有效减小了转矩脉动,同时简化了系统控制参数,提高了控制的可靠性.数字仿真和试验结果验证了这些设计思想的正确性.     

Halbach阵列对传统永磁电机的影响

在消化和吸收国内外研究成果的基础上，系统阐述了Halbach列的组成及其特点，探讨了传统稀土永磁电机发展过程中存在的一些缺陷，以Halbach双凸极电机和Halbach爪极电机为例，归纳了Halbach电机的特点，分析了Halbach列对传统永磁电机的影响。     

单斩电流滞环控制的双凸极永磁电机三相桥式功率变换器中的电流尾巴

双凸极永磁电机的功率控制器通常采用电流滞环斩波控制.文中基于12/8极转子斜槽式双凸极永磁电机,研究了单斩电流滞环控制的三相桥式功率控制电路;提出采用这种控制方案的三相桥式变换器,每相绕组在关断时段内,会出现两段电流尾巴,削弱电机出力,增加系统损耗.文中首先介绍了单斩电流滞环控制方案,给出基于这种控制方案的三相桥式功率变换器稳态工作原理分析,阐述了电流尾巴的产生机理,给出电流尾巴出现时刻及电流尾巴大小的解析式,指出其危害性,并讨论了三相绕组反电势对称性及霍尔位置调整的准确度对电流尾巴的影响,实验结果证明了文中研究及结论的正确性.     

Implementation of the DSPM model using a commercial finite element system

A solution procedure based on the use of the finite element method (FEM) was developed to solve the Donnan steric-partioning pore model (DSPM) for a nanofiltration membrane coupled with a boundary layer. The numerical solution of nanofiltration models like DSPM is usually carried out by combining an integration method like Runge-Kutta with an iterative procedure that starts from guessed permeate concentrations values. However, this approach may have problems of lack of convergence. As an alternative procedure, a finite element system is used to easily implement the transport equation for the membrane and the boundary layer with Donnan-steric conditions in both membrane sides. To test the solution method, an analytical solution was developed for the transport of an uncharged solute across a membrane with boundary layer. Afterwards, the method was applied to the calculation of binary and ternary ionic systems and its performance was compared with that obtained with the classical iterative method. The developed methodology benefits from the accuracy of FEM and the representation and analysis capabilities of the software used.     

Mg2+/Li+纳滤分离研究（英文）

The Mg2+/Li+/Cl solutions were filtrated with a commercially available DK nanofiltration membrane to investigate the possibility to enrich the lithium component.The investigation was significant as such an approach might be a competing substitute for the present lithium purification industry and the environmental protection purpose.The Donnan steric pore model(DSPM) was implemented for the prediction.The separation of Mg2+/Li+was mainly affected by the working pressure(or the permeation flux) and a limiting separation factor was found around 0.31.The effective membrane charge density was evaluated and its dependence on the permeation flux as well as the ion pattern was discussed.For predicting an actual separation of electrolytes,the experimental investigation seems necessary for the reliability and efficiency.     

永磁体和气隙对双凸极永磁电动机转矩脉动的影响

新型双凸极永磁电动机(DSPM)的定子和转子均为双凸极结构,电动机内有显著的边缘效应和局部饱和现象。转矩特性(包括输出转矩和转矩脉动)是电机设计和控制过程中非常重要的研究对象。从电动机永磁体的大小和气隙的厚度等方面研究,找出了永磁体尺寸和气隙厚度等因素对电机转矩脉动的影响。通过计算比较,得出了能使电动机转矩脉动较小的永磁体尺寸和气隙厚度。研究对该类电动机的设计有一定的借鉴意义。     

转子极弧对永磁双凸极电机性能的影响

介绍了一种新型12／8永磁双凸极电机的结构和工作原理，利用ANSYS软件中的二维电磁场建立电机本体模型，并进行有限元仿真计算，分析转子极弧变化对磁链、电感、反电势以及转矩等静态特性的影响，为电机设计和控制奠定基础。