异步电机按定子磁链定向的转矩连续控制

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基于模型参考自适应理论转子磁链观测器的设计

感应电动机是一个多变量、强耦合、非线性的控制对象,性能优良的非线性磁链观测器成了电机控制中一个非常重要的研究内容。文章基于模型参考自适应系统理论设计了转子磁链观测器的数学模型,并对所设计的模型进行了仿真分析,仿真结果验证了理论的正确性。     

基于扩展Kalman滤波器电机转子磁链观测器的设计

交流感应电机是多变量、非线性、强耦合的高阶系统，所有这些控制方案的实现，几乎都需要转子磁链信息。基于此提出了一种基于扩展Kalman滤波器理论的磁链观测器的设计方法，并对所设计的观测器进行了计算机仿真，得到了良好的观测效果。     

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.     

无人直升机旋翼转速控制器设计

针对无人机的特殊性以及对电机动态性能的要求,设计了一种以ARM芯片LPC2148为核心的旋翼转速控制器。首先分析了直升机的飞行特点以及原旋翼转速控制器的不足,设计基于EKF和矢量控制的新旋翼转速控制器,并对扩展卡尔曼滤波法和矢量控制的模块进行说明,且给出了MATLAB仿真结果,验证了控制系统的正确性。     

基于预测控制的直接转矩控制系统的研究

针对异步电动机直接转矩控制（DTC）系统在低速时由于开关频率不稳定而引起转矩脉动较大的缺点，提出了一种预测控制方法。该方法根据转矩和定子磁链的误差来确定应该施加的参考电压矢量，最后利用空间矢量脉宽调制（SVPWM）方法来合成该矢量，这样即保证了逆变器的开关频率恒定，从而大大降低转矩脉动。仿真结果表明，在低速下定子磁链轨迹近似为圆，转矩脉动不明显。     

Novel torque ripple minimization algorithm for direct torque control of induction motor drive

To elucidate the principles of notable torque and flux ripple during the steady state of the conventional direct torque control (DTC) of induction machines, the factors of influence torque variation are examined. A new torque ripple minimization algorithm is proposed. The novel method eradicated the torque ripple by imposing the required stator voltage vector in each control cycle. The M and T axial components of the stator voltage are accomplished by measuring the stator flux error and the expected incremental value of the torque at every sampling time. The maximum angle rotation allowed is obtained. Experimental results showed that the proposed method combined with the space vector pulse width modulation(SVPWM) could be implemented in most existing digital drive controllers, offering high performance in both steady and transient states of the induction drives at full speed range. The result of the present work imphes that torque fluctuation could be eliminated by imposing proper stator voltage, and the proposed scheme could not only maintain constant switching frequency for the inverter, but also solve the heating problem and current harmonics in traditional induction motor drives.     

Direct - Torque, Neuro - Fuzzy Control of Induction Motor

Fuzzy systems are currently being used in a wide field of industrial and scientific applications. Since the design and especially the optimization process of fuzzy systems can be very time consuming, it is convenient to have algorithms which construct and optimize them automatically. In order to improve the system stability and raise the response speed, a new control scheme, direct - torque neuro - fuzzy control for induction motor drive, was put forward. The design and tuning procedure have been described. Also, the improved stator flux estimation algorithm, which guarantees eccentric estimated flux has been proposed.     

Experimental and Finite Element Study of Steady State Micro-cutting Characteristics of Aluminum Alloy （2A12）

This paper studies the micro-cutting characteristics of aluminum alloy (2A12) based on a series of orthogonal experiments and finite element method (FEM) simulations. An energy-based ductile failure law was proposed in the FEM simulation. The simulated cutting forces and chip morphology were compared with experimental results. The simulation result indicates that there is a close relationship between the cutting force and cutting heat. The micro-cutting force decreases as the heat flux vector increases. Both the cutting heat and the micro-cutting force need a finite time to achieve a steady state. It is observed that with the cutting speed of 169.95 m/min and uncut chip thickness of 6 μm, the heat flux vector in the workpiece increases to a stable value after 0.06 ms; meanwhile, the principal cutting force decreases to a steady state correspondingly, i.e., the micro-cutting process achieves the steady state. It is concluded that the steady state micro-cutting simulation can reflect the cutting process accurately.     

无刷双馈电机的建模与仿真

无刷双馈电机（BDFM）作为一种新型电机,兼有绕线式转子异步电机和同步电机的优良特性,尤其适合于变速恒频发电领域,通过分析无刷双馈电机的结构及工作原理,建立了基于转子速坐标系的d-q轴无刷双馈电机数学模型,根据所得的数学模型,对无刷双馈电机的各种运行方式进行了仿真分析,采用MATLAB/Simulink进行了计算机仿真研究,得出了各种运行方式下的仿真波形,仿真结果验证了数学模型的正确性和可行性,并得到了一些有益的结论.     

变频器最小母线电容参数计算及其控制策略

提出一种基于交直交变频器的直流六脉波电压小电容结构和变频控制策略,实时采样母线脉动电压并依据磁链轨迹需求计算空间电压矢量调制脉宽,得到谐波含量较少的逆变输出.在仅考虑电动机感性能量回馈的情况下,根据逆变侧瞬时回馈电流大小及时间计算出直流母线最小电容参数,同时针对瞬时负载波动和转速突变产生的惯性能量回馈问题,用瞬时关断输...     

一种先进的矢量控制方案的研究

感应电动机是一个多变量、强耦合、非线性的控制对象。传统的矢量控制只是进行3／2，2／2变换，变换之后的系统难以进行PID调节器设计，本提出的解耦控制方案可以容易进行PID参数设计。理论和仿真试验结果都表明，这种控制方案可以得到磁链与转速静态解耦，易于工程实现。     

基于微分几何理论的感应电机输入输出解耦控制

感应电动机是一个多变量、强耦合、非线性的控制对象。微分几何理论是目前分析非线性系统的一种很有效的数学工具。文章介绍了应用微分几何理论对感应电机转速和磁链进行解耦控制的方法,并对解耦控制系统进行了仿真,仿真结果验证了理论分析的正确性。     

Dynamic modelling and robust current control of wind-turbine driven DFIG during external AC voltage dip

INTRODUCTION Due to concerns about emissions from fossil fuels and the depletion of fossil fuel resources, re- newable energy systems are becoming a topic of great interest and investment in the world. In particular, wind energy has been the subject of much recent research and development. In order to overcome the problems associated with fixed-speed wind-turbine system and to maximize the wind energy capture, many new wind farms will employ wind turbines based on Doubly-Fed Induction Ge…     

Rotor broken bar fault diagnosis for induction motors based on double PQ transformation

A new rotor broken bar fault diagnosis method for induction motors based on the double PQ transformation is pre-sented. By distinguishing the different patterns of the PQ components in the PQ plane,the rotor broken bar fault can be detected. The magnitude of power component directly resulted from rotor fault is used as the fault indicator and the distance between the point of no-load condition and the center of the ellipse as its normalization value. Based on these,the fault severity factor which is completely independent of the inertia and load level is defined. Moreover,a method to reliably discriminate between rotor faults and periodic load fluctuation is presented. Experimental results from a 4 kW induction motor demonstrated the validity of the proposed method.     

感应电机多参数辨识的实验研究

从理论及试验上深入地分析了定子电阻参数变化对定子磁链估计的影响。同时,在伪降阶磁链观测器的基础上提出了定子电阻、转子电阻及转速的参考模型自适应律,从实验结果可以看出电机参数依据本文所得到自适应律进行独立辨识时可以获得的估计精度。     

Simulation software for CRH2 and CRH3 traction driver systems based on SIMULINK and VC

Simulation models of traction driver systems were established using SIMULINK, according to the actual structure and parameters of China Railway High-Speed 2 (CRH2) and China Railway High-Speed 3 (CRH3) trains. In these models, the traction motor adopts transient current control and an indirect rotor magnetic field orientation vector control strategy, and the traction converter uses sinusoidal pulse width modulation (SPWM) and space vector pulse width modulation (SVPWM) methods. After these models are transformed in VC++ program, and a friendly interface and data processing system are constructed, simulation software is obtained for CRH2 and CRH3 traction driver systems. On this basis, the operational performance of a traction converter was simulated and analyzed at different train speeds and in different conditions. The simulation results can provide a reference for the actual design and production of a traction converter.     

无刷直流电机转子状态检测方法与仿真

研究了电机控制的数学模型,利用扩展卡尔曼滤波器对电机转子的状态做出了最小方差估计,通过计算机仿真验证了此方法的有效性。     

Design and implementation of a position sensorless control method for brushless DC motors

Because brushless direct current (BLDC) motors have the advantages of a compact size, high power density, high efficiency, and long operating life time, they are widely used in many industrial products and electric traction systems. It is known that the BLDC motors have no brushes for commutation. They are commutated with electronically commutation. So, the rotor position information of the BLDC motors must be known to understand which winding will be energized according to the energizing sequence. In most of the existing BLDC motor drivers, rotor position information is detected by Hall effect sensors. This kind of mechanical position sensors will bring additional connections and costs, reliability decrease and noise increase. In order to improve the control performance and extend the range of speed regulation for BLDC motors, a position sensorless control method is proposed in this paper. In the proposed control method, rotor position information of the BLDC motors is detected from the back electromagnetic forces (back-EMFs) which are estimated by an unknown-input observer with line to line currents and line to line voltages. For the purpose of verifying the effectiveness of the proposed control method, a model is built and simulated on the Matlab/Simulink platform. The simulation results show that the speed regulation performance of BLDC motors is improved compared with using Hall effect sensors. At the same time, the reliability of the BLDC motors is improved and the costs of them are reduced because the position sensor is eliminated.     

基于S7—300PLC的轧机控制系统设计

设计了基于可编程控制器（PLC）的轧机电气控制系统,反馈单元应用高精度光电编码器作为速度传感器,采用矢量控制的变频调速方式控制主传动电机和辊道电机转度,以PLC为主控制单元使得辊道转速和主传动电机速度完全一致。实践表明,设计的整套系统具有良好的调节品质,稳定可靠的性能,并且维护简单。