永磁同步电动机调速系统的模糊控制与仿真

对电动汽车驱动用永磁同步电动机(Permanent Magnet Synchronous Motor 缩写为PMSM)的调速系统进行模糊控制并对其结果进行仿真.对PMSM进行数学建模,根据其数学模型在MATLAB/Simulink下建立PMSM、PMSM测量环节、dq/abc转换器和PWM三相逆变器的仿真模块并进行封装.采用二维模糊设计, 以电动汽车行驶时所要求的电动机转速n′与电动机的实际转速n之间的偏差E和其偏差变化率EC作为系统的输入变量,把控制占空比的电流信号U作为输出语言变量,进行模糊控制器的设计.根据PMSM的各模块和所设计的模糊控制器,在MATLAB /SIMULINK下创建电动汽车PMSM调速系统的模糊控制仿真结构模型,并进行仿真,从而验证控制方法的正确性.     

基于Matlab/Simulink电动汽车异步电动机模糊PI控制

在以转子磁场定向的电动汽车用异步电动机矢量控制的基础上,采用模糊PI控制的方法,以使电动汽车获得良好的调速性能.用Matlab/Simulink仿真工具箱建立了整个系统的模型.仿真结果表明,采用模糊PI控制的电动汽车异步电动机具有高质量的调速性能.     

无刷直流电机的变论域模糊自适应PID控制系统设计

为了改善无刷直流电机的调速性能,针对普通模糊PID速度控制器的缺陷,研究了基于变论域思想的自适应模糊PID控制器及其在BLDCM控制系统中的应用.在Matlab仿真平台下,建立了BLDCM的模型,构建了BLDCM的电流、转速双闭环控制系统,其中转速环采用了变论域自适应模糊PID控制器,电流环采用普通PID控制器.仿真结果表明,与常规PID控制器和普通模糊PID相比,采用变论域自适应模糊PID控制器的优势在于:转速输出无超调、响应速度快、控制精度高,具有较强的鲁棒性和自适应能力.     

基于模糊控制的纯电动汽车距离控制

提出了一种电动机模型和动态安全距离模型,并在Carsim平台上搭建纯电动汽车整车动力学模型.设计了模糊距离控制器,并建立Simulink和Carsim联合仿真平台,在该平台上对纯电动车辆模糊距离控制器进行仿真分析.结果表明:同没有控制器的车辆相比,被控车辆能始终保证同前车车距在5 m以上的安全距离,同前车起始车距在50,80,100 m车距时均能将两车的最小距离控制在5 m以上,相邻车道切入工况下也能够有效防止追尾事故,避免碰撞,提高了车辆的主动安全性和道路的通过效率.     

基于遗传算法的模糊自整定双环直流调速系统

将遗传算法与模糊控制相结合,针对工程上通常采用直流调速系统,详细分析双闭环调速系统的模糊自整定PID控制,设计了模糊控制器并对直流双闭环调速系统进行建模.对系统的转速环的动态性能、抗干扰性能进行仿真分析.最后,与传统PID控制进行比较,得到模糊自整定控制可以大大提高控制效果、抗扰性能强、系统响应速度快、动态性能好等优点.     

基于观测器的异步电动机模糊自适应控制

研究了异步电动机位置跟踪控制问题.设计降维观测器用于估计异步电动机的角速度,利用模糊逻辑系统逼近系统中的非线性函数,并基于反步法实现异步电动机的自适应模糊控制.所提出的控制器能够有效地跟踪给定的参考信号.仿真结果验证了该方法的有效性.     

基于ADVISOR的纯电动汽车驱动转矩 双模糊控制策略

针对电动汽车行驶工况及驾驶员操作具有一定非线性和时变不确定性的问题,对整车控制器的控制算法和电池管理系统进行了研究,提出了一种驱动转矩分配的双模糊控制策略。对纯电动汽车建立整车动力学模型和驾驶员输入参数模型,以基本转矩模糊控制器和补偿转矩模糊控制器来求解,并优化驱动转矩值,采用CAN总线通讯经过电机驱动器来控制驱动电机的转矩输出。以CYC_HWFET高速工况和CYC_EUDC中低速工况为例,基于ADVISOR平台对双模糊控制器的电动汽车进行性能仿真分析。结果表明,所设计的双模糊控制器在满足纯电动汽车动力性要求的同时,也能获得较优的经济性且动力电池利用效率较高。     

轮毂电动机驱动电动汽车自适应巡航系统控制策略

以轮毂电动机驱动电动汽车为研究对象,采用分层控制策略提出自适应巡航系统,结合上层模型预测控制器与下层PID (proportion integral differential)控制器,针对复杂的纵向跟随工况,对轮毂电动机输出的驱动力矩进行精确控制.提出基于前车加速度的可变车头时距策略,利用模型预测控制算法(model predictive control, MPC)求解本车期望加速度的上层控制器,利用PID算法求解整车前后轴驱动力矩,并输入到轮毂电动机的下层控制器,实现前后轮驱动力矩分配,最终实现车辆纵向自适应巡航.建立联合仿真模型,针对匀速前进、紧急制动、城市循环工况等场景,对所提出的自适应巡航分层控制策略进行验证,结果表明：所提出的自适应巡航系统控制策略针对纵向复杂行驶工况的跟驰效果良好,跟驰过程中车间距误差较小,加速度变化与电动机驱动转矩变化可以较好地进行同步与响应.     

MRAC异步电动机直接转矩控制系统转速辨识研究

针对异步电动机直接转矩交流调速系统的转子转速辨识问题,文章分析和研究了模型参考自适应控制(MRAC)速度辨识算法.在对异步电动机转子转速和磁链观测深入研究的基础上,基于超稳定性理论证明了该算法的稳定性,构建了模型参考自适应速度辨识系统并设计了该算法的自适应率;在MATLAB7.04软件平台上,建立了无速度传感器直接转矩控制系统的仿真模型并进行了仿真,仿真试验结果表明,该系统控制性能和精度良好,验证了算法的正确性和可实践性.     

改进型PI控制在纯电动汽车调速系统上的应用

为了提高永磁同步电机(PMSM)驱动的纯电动汽车(PEV)调速系统性能,对其调速控制器进行研究.在经典PI控制的基础上,提出一种改进型PI调速控制器.利用MATLAB仿真软件对永磁同步电机驱动的纯电动汽车进行数学建模并验证改进型PI调速控制器的效果.仿真实验表明,相比于传统PI调速控制,基于改进型PI调速控制拥有更小的超调量和稳态误差,且转速追踪响应时间更短.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

An affordable accurate evaluation of the binding conformations predicted by molecular docking studies in bio-system

Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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