电动汽车用永磁同步电机模糊控制

本文研究了电动汽车用的正弦波永磁同步电机（PMSM）模糊控制的仿真分析。分析了永磁同步电机用于矢量控制的数学模型，并建立了基于其数学模型的电机控制仿真软件包。在PMSM双闭环调速系统中，电流环采用滞环电流调节器，速度环采用参数自调整模糊PI控制。通过对传统PI控制和模糊PI控制方法的仿真实验，去验证这种模糊PI控制方法响应快、无超调，与传统PI控制方法相比具有更好的稳定性和抗干扰能力。所开发的电动汽车用的永磁同步电动机驱动系统具有良好的性能，能够很好地满足电动汽车性能要求。     

永磁同步电动机控制半实物仿真系统设计

为满足永磁同步电动机控制的教学和科研需要,利用dSPACE仿真系统的软、硬件环境设计一个永磁同步电动机控制半实物仿真系统.基于dSPACE硬件和永磁同步电动机及其驱动装置设计硬件系统;利用Simulink和ControlDesk软件平台设计半实物仿真软件系统;给出永磁同步电动机控制半实物仿真系统的工作流程;用传统的PI...     

面向状态空间的永磁同步电动机控制器设计

针对传统矢量控制中永磁同步电动机解耦不充分的问题，设计了基于反馈线性化的永磁同步电动机状态反馈控制器。该设计首先利用反馈线性化对内嵌式永磁同步电动机数学模型进行处理，并基于线性化模型，采用线性二次型调节器设计状态反馈控制器；随后采用灰狼优化算法对线性二次型调节器中的加权矩阵Q和R进行优化；最后利用Simulink软件对状态反馈控制器进行仿真，并通过2.2 kW永磁同步电动机实验平台对控制器中的控制算法进行实验验证。结果表明，该控制方法在永磁同步电动机的抗负载扰动和转速跟踪方面有着良好的控制效果，能够保证电动机在变载、变速和正反转情况下稳定运行。     

稀土永磁同步电动机调速的研究

本讨论稀土永磁同步电动机空载反电动势R的取值是电磁设计的关键所在．它关系列永磁同步电动机运行性能的效率和功率因数的大小，采用变压变频(VVVF)交流调遣系统，可以保持电源的频率f与电源的电压U以及与空载反电动势E0的对应关系，结合稀土永磁同步电动机的设计值和试验实测值。阐明变压变频(VVVF)交流调速系统是稀土永磁同步电动机的最佳调速方法。     

永磁同步电动机网络有限时间PD同步控制

针对永磁同步电动机系统的参数处在某些范围内出现的混沌振荡现象,以单个永磁同步电动机系统为节点,建立多电机互联网络模型,研究复杂电机网络的混沌振荡同步控制。通过所设计的PD控制方法,使整个电动机网络在有限时间内达到目标平衡点,确保电机网络的稳定。理论分析和仿真结果表明,所设计的PD控制器能够有效地提高电机网络的稳定性和收敛时间,对保证电动机传动系统的协调同步运行具有一定的应用价值。     

一类永磁同步电动机的TSM控制器设计

基于永磁同步电动机精确的数学模型,针对永磁同步电动机绕组相电流和转速强耦合特性,依据中继切换控制机制和有限时间收敛的终端滑动模态控制机制,考虑了永磁同步电动机的有限时间跟踪问题。给出了其终端滑模控制器的设计方案。在所设计的控制作用下,闭环系统将在有限时间内达到平衡状态。并且保证了闭环系统所有信号的有界性和平衡点的全局稳定性,以及系统在有限时间内精确地跟踪给定的参考信号。最后对一具体的永磁同步电动机模型进行了数值仿真,仿真结果表明在所设计的终端滑模控制器作用下,系统的跟踪误差在有限时间内达到零,验证了所提算法的正确有效性。     

空调用永磁同步电动机直接转矩控制的仿真建模研究

将计算机仿真技术应用于永磁同步电动机控制器的设计研究,根据永磁同步电动机的数学模型,结合直接转矩控制理论,以空调用永磁同步电动机为例,利用Matlab/Simulink软件,对永磁同步电动机直接转矩控制仿真建模,给出其仿真结果。     

基于FPGA的永磁同步电动机参数辨识技术

针对永磁同步电动机运行时参数变化的问题,提出了一种基于FFRLS的变遗忘因子最小二乘法的电动机参数辨识方法以及实验设计方案。该方法引入误差概念,使遗忘因子与引入的误差成反比关系,根据实时数据进行动态调整,进而解决了FFRLS单一遗忘因子切换问题,改善辨识系统的收敛速度和稳定性能。利用MATLAB/Simulink对变遗忘因子最小二乘法进行了仿真验证;搭建了以FPGA为核心的永磁同步电动机在线参数辨识平台。实验结果证明,所提方法可以有效地实现电动机参数辨识,可以应用在永磁同步电动机的高性能控制中。     

部分线性化控制永磁同步电动机混沌系统的实现

永磁同步电动机在一定工作情况下将呈现混沌运动，这种现象可能是有害的，采用部分线性化方法控制对永磁同步电动机混沌模型进行控制，实现被控系统的稳定化．本文详细说明了如何应用matlab编程求解方程以及如何仿真进行数值研究以证明控制律简单有效.     

永磁同步电动机状态方程研究和起动过程仿真

由于永磁同步电动机与普通三相异步电动机相比，起动过程较为复杂，可利用坐标变换的PARK方程，推导出永磁同步电动机的状态方程，最后利用四阶龙格-库塔法，编写样机的起动过程仿真程序，并得出仿真结果。     

Study on inverter fault-tolerant operation of PMSM DTC

This paper presents an investigation of inverter fault-tolerant operation for a permanent magnet synchronous motor （PMSM） direct torque control （DTC） system under various inverter faults. The performance of a faulty standard 6-switch inverter driven PMSM DTC system is analyzed. To avoid the loss or even disaster caused by the inverter faults, a topology-modified inverter with fault-tolerant capability is introduced, which is reconfigured as a 3-phase 4-switch inverter. The modeling of the 4-switch inverter is then analyzed and a novel DTC strategy with a unique nonlinear perpendicular flux observer and feedback compensation scheme is proposed for obtaining a continuous, disturbance-flee drive system. The simulation and experimental results demonstrate that the proposed inverter fault-tolerant PMSM DTC system is able to operate stably and continuously with acceptable static and pretty good dynamic performance.     

一种新型高功率密度的正弦波永磁电机

A novel high power-density PMSM (permanent magnetic synchronous motor) with independent magnetic flux path for each phase is proposed in the paper.The complex mathematic model of PMSM is simplified by decoupling of magnetic flux paths between motor phases.In addition,harmonic compoments are lowered through optimum design of EMF (electric motive force) wave.Thus the ripple torque caused by EMF wave distortion is suppressed.     

基于CMAC学习控制的永磁同步电机仿真研究

将一种基于CMAC神经网络的PID控制器引入到永磁同步电动机交流调速系统中,取代传统的PMSM双环控制系统中的转速外环PI控制器.仿真结果表明,运用该控制方法与规则自校正模糊控制相比具有较快的响应速度、较高的稳态精度和较强的鲁棒性.     

Magnetic field and performance analysis of a tubular permanent magnet linear synchronous motor applied in elevator door system

A novel elevator door driven by tubular permanent magnet linear synchronous motor （TPMLSM） is presented. This TPMLSM applies axial magnet array topology of the secondary rod, air-cored armature windings and slotless structure of the forcer to improve the stability of the thrust. The influence of two major dimensions, the pitch and radius of the permanent magnet （PM）, on magnetic field was studied and the best values were given by the finite element analysis （FEA）. The magnetic field, back EMF and thrust of the motor were analyzed and the PM size was optimized to reduce the harmonic components of the magnetic field and improve the performance of the motor. Predicted results are validated by the experiment. It is shown that the performance of the motor and the novel elevator door system is satisfying.     

Enhanced control of DFIG-used back-to-back PWM VSC under unbalanced grid voltage conditions

This paper presents a unified positive-and negative-sequence dual-dq dynamic model of wind-turbine driven doubly-fed induction generator(DFIG) under unbalanced grid voltage conditions. Strategies for enhanced control and operation of a DFIG-used back-to-back(BTB) PWM voltage source converter(VSC) are proposed. The modified control design for the grid-side converter in the stationary αβ frames diminishes the amplitude of DC-link voltage ripples of twice the grid frequency,and the two proposed control targets for the rotor-side converter are alternatively achieved,which,as a result,improve the fault-ride through(FRT) capability of the DFIG based wind power generation systems during unbalanced network supply. A complete unbalanced control scheme with both grid-and rotor-side converters included is designed. Finally,simulation was carried out on a 1.5 MW wind-turbine driven DFIG system and the validity of the developed unified model and the feasibility of the proposed control strategies are all confirmed by the simulated results.     

A spatially triggered dissipative resource distribution policy for SMT processors

Programs take on changing behavior at nmtime in a simultaneous multithreading （SMT） environment. How reasonably common resources are distributed among the threads significantly determines the throughput and fairness performance in SMT processors. Existing resource distribution methods either mainly rely on the front-end fetch policy, or make distribution decisions according to the limited information from the pipeline. It is difficult for them to efficiently catch the various resource requirements of the threads. This work presents a spatially triggered dissipative resource distribution （SDRD） policy for SMT processors, its two parts, the self-organization mechanism that is driven by the real-time instructions per cycle （IPC） performance and the introduction of chaos that tries to control the diversity Of trial resource distributions, work together to supply sustaining resource distribution optimization for changing program behavior. Simulation results show that SDRD with fine-grained diversity controlling is more effective than that with a coarse-grained one. And SDRD benefits much from its two well-coordinated parts, providing potential fairness gains as well as good throughput gains. Meanings and settings of important SDRD parameters are also discussed.     

Amenable performance management in higher education: integrating principles of agency and stewardship theories

ABSTRACT

The considerable transformation of higher education (HE), driven by the South African government's demand for accountability of resources for the attainment of its mandate has altered the ‘business’ of academia. In response to the financial austerity measures, performance management (PM) systems have been implemented in South African HE to monitor and enhance staff performance. This article conceptualizes PM in higher education using agency and stewardship theories. Data emanates from a phenomenological study of academic heads of department's (HOD) experiences of PM. There is evidence that agency theory may be an appropriate mechanism to achieve explicit accountability, and to monitor and enhance performance. However, it is fraught with problems within academic contexts. The findings demonstrate limitations of agency theory with regard to the stewardship of academics. Thus foregrounding the need for the retention of approaches underpinned by stewardship theory. This article thus makes a contribution in terms of providing a proposition for an analytical framework that integrates agency and stewardship theories in researching PM in HE. Central to this proposition is working within a continuum of these theories to mediate the apparent tension between control and collaboration/collegiality.     

Position Sensorless Control for Permanent Magnet Synchronous Motor Using Sliding Mode Observer

An approach of position sensorless control for permanent magnet synchronous motor （ PMSM ） is put forward based on a sliding mode observer. The mathematical model of PMSM in a stationary αβ reference frame is adopted, and the system is controlled by the digital signal processor （ DSP; TMS320LF2407 according to the control achieve closed loop operation of the motor, the stator theory of sliding mode observer. In order to magnetic field should be vertical with the rotor magnetic field and be synchronous with rotor rotating, so the position and speed of PMSM is estimated in real time and the estimated position is modified continuously. The simulation results indicate that the proposed observer has high precision is more robust to the parametric variation and load in estimation of PMSM position and speed, and torque disturbance.