三维多层仿形织造过程多机协同智能控制技术

三维多层仿形织造过程多机同步协同控制是其关键技术之一。本文通过对三维多层仿形织造工艺技术的研究,依据磁场磁链定向控制作用机理,提出了一种对磁场磁链定向和变力矩控制的方法,来分别对多个感应电动机进行速度和力矩跟踪智能控制。依据控制方法,通过建立全维转子状态估计器,来辨识感应电动机的转子速度、定子和转子电阻、瞬时外负载等参数。由外负载辨识结果与速度、力矩PID控制器来确定感应电动机的转矩电流,实现感应电动机速度与力矩控制。仿真实验与三维多层仿形织造工程试验结果表明了该智能控制方法的先进性和实用性。     

异步电动机的非线性自适应控制

本文针对对磁场定向的ｄ－ｑ坐标系下的４阶包含机、电动力学的异步电动机的模型，运用非线性自适应的反馈线性化的控制方法，设计一个新近跟踪负载和转子电阻实际值的非线性辩识算法，一旦这两个未知常数被辩识，则可实现速度和磁链调节的解耦控制，仿真结果证明系统具有良好的稳、动态性能。     

具有不确定负载的交流电机自适应后推控制方法

将后推控制方法应用于非线性感应电动机的控制系统中,并把负载作为不确定在数,引入自适应的机制。通过状态观测,感应电动机的速度和转子磁链得到良好的跟踪,改善了系统的性能。仿真结果证明了该方法的有效性。     

基于逆系统原理的感应电动机滑模速度控制

针对目前逆系统原理应用于感应电动机调速系统中时往往忽略参数不确定性的问题,从感应电动机的非线性模型出发,采用逆系统理论建立了转子电阻与负载参数不确定的感应电动机伪线性控制系统模型;提出了一种采用变指数趋近律实现的防抖动自适应滑模变结构控制方法,并将该控制方法应用于感应电动机伪线性控制系统中。仿真结果表明,基于逆系统原理的感应电动机滑模速度控制方法能够有效抑制系统参数的不确定性,提高系统的稳定性和控制精度。     

异步电机转子电阻辩识方法的建模与仿真

研究异步电机稳定性优化控制问题,异步电机转子电阻受温度变化、集肤效应等影响,具有时变性和非线性,影响系统稳定性分析。传统方法对异步电机转子电阻状态辩识准确率低。为了准确和快速对转子电阻进行状态辩识,提出一种扩展卡尔曼滤波的异步电机转子电阻辩识方法。将转子电阻看成系统状态变量,设计一种扩展卡尔曼滤波技术的转子电阻估计器,通过测量电机定子电压、电流,实现对转子电阻在线辩识。在MATLAB/Simulink中建立仿真模型,仿真结果表明,异步电机转子电阻改进辩识方法可提高转子电阻辨识准确率。     

基于在线搜索的感应电动机模糊节能控制

针对传统的按转子磁链定向的感应电动机间接矢量控制系统在轻载情况下效率低的问题,提出了一种将基于在线搜索的模糊节能控制方法引入到传统的感应电动机控制系统中的设计方案。该方案在感应电动机瞬态运行时采用按转子磁链定向的间接矢量控制方法;在感应电动机稳态运行时采用基于在线搜索的模糊节能控制方法,以测得的直流输入功率作为控制量进行模糊寻优控制,可使电动机在最大效率处运行。仿真结果验证了该方案的正确性和有效性。     

交流感应电动机的调压系统能量分析

从经济的角度考虑,感应电动机的控制中经常用到调压系统.对恒转矩负载来讲,在不考虑转子构成材料的情况下,很难达到稳定和宽范围调速的目的.但对于泵类和风机类负载而言,如何通过改变定子输入电压来达到节能的目的,是感应电机调压系统的另一个重要应用领域.本文通过电机的数学模型以及机电传动方程,详细地分析了在泵类负载情况下,电机各参数随输入电压改变的动态变化规律,特别是输入功率的变化情况,从而提出了通过合适的控制方案来实现能量最佳控制.     

基于Petri模糊神经网络磁通观测器的感应电动机无速度传感器控制

利用Petri模糊神经网络构造电流观测器,基于电流观测值构造感应电动机的转子磁通观测器,根据磁通观测值进行电动机转子速度的计算.基于一种新颖的感应电动机解耦模型,设计了感应电动机的滑模反推控制器,并给出了Petri模糊神经网络的收敛性证明.通过MATLAB仿真验证了系统设计的有效性.     

感应电动机的T-I型等效电路

感应电动机的矢量控制通过对定子电流的励磁分量和转矩分量进行解耦,从而实现对磁链和电磁转矩进行分别控制。然而,传统的感应电动机T型等效电路所表示的正弦稳态下感应电动机转子侧、定子侧及气隙所包含的电磁关系并不能明显地反映这种解耦情况。有鉴于此,在感应电动机的T型等效电路基础上,提出了一种感应电动机的T-I型等效电路。这种等效电路有助于更好地理解转子磁场定向的感应电动机矢量控制原理。     

矿山变频矢量控制系统效率优化方案研究

针对矿山变频调速系统感应电动机采用恒定磁通控制,存在损耗严重、运行效率低的问题,提出了一种矿山变频矢量控制系统的效率优化控制方案。该方案在两相旋转d-q坐标系下,建立了考虑定、转子铜损和铁损的系统损耗模型,推导得到不同运行工况下电动机损耗与转子磁链之间的对应关系;为改善因弱磁运行而造成的系统动态响应过慢问题,通过优化转矩电流和磁链电流比重关系,获得电动机电磁转矩的快速响应和转速跟踪。基于DSP+FPGA控制系统搭建22kW三电平感应电动机调速系统实验平台,实验结果表明,该优化方案可以降低感应电动机矢量控制系统运行损耗,提高系统运行效率,并保证系统的稳态性能和动态响应性能。     

Adaptive sensorless robust control of AC drives based on sliding mode control theory

This paper focuses in the design of a new adaptive sensorless robust control to improve the trajectory tracking performance of induction motors. The proposed design employs the so‐called vector (or field oriented) control theory for the induction motor drives, being the designed control law based on an integral sliding‐mode algorithm that overcomes the system uncertainties. This sliding‐mode control law incorporates an adaptive switching gain in order to avoid the need of calculating an upper limit for the system uncertainties. The proposed design also includes a new method in order to estimate the rotor speed. In this method, the rotor speed estimation error is presented as a first‐order simple function based on the difference between the real stator currents and the estimated stator currents. The stability analysis of the proposed controller under parameter uncertainties and load disturbances is provided using the Lyapunov stability theory. The simulated results show, on the one hand that the proposed controller with the proposed rotor speed estimator provides high‐performance dynamic characteristics, and on the other hand that this scheme is robust with respect to plant parameter variations and external load disturbances. Finally, experimental results show the performance of the proposed control scheme. Copyright © 2006 John Wiley & Sons, Ltd.     

Adaptive speed/position control of induction motor based on SPR approach

A sensorless speed/position tracking control scheme for induction motors is proposed subject to unknown load torque via adaptive strictly positive real (SPR) approach design. A special nonlinear coordinate transform is first provided to reform the dynamical model of the induction motor. The information on rotor fluxes can thus be derived from the dynamical model to decide on the proportion of input voltage in the d-q frame under the constraint of the maximum power transfer property of induction motors. Based on the SPR approach, the speed and position control objectives can be achieved. The proposed control scheme is to provide the speed/position control of induction motors while lacking the knowledge of some mechanical system parameters, such as the motor inertia, motor damping coefficient, and the unknown payload. The adaptive control technique is thus involved in the field oriented control scheme to deal with the unknown parameters. The thorough proof is derived to guarantee the stability of the speed and position of control systems of induction motors. Besides, numerical simulation and experimental results are also provided to validate the effectiveness of the proposed control scheme.     

ON STABILITY AND PERFORMANCE OF INDUCTION MOTOR SPEED DRIVES WITH SLIDING MODE CURRENT CONTROL

A novel inner loop sliding mode current control scheme for induction motor speed drives is proposed in this paper. The controller design is based on the nonlinear mathematical model of an induction motor in a coordinate system oriented along the rotor flux. The parameters of the PI speed controller are taken into consideration in the inner loop sliding mode current control. Rigorous stability verification for the overall system is provided in this paper. The chattering in sliding mode control is attenuated using the reaching law design method. The experimental results show that the proposed approach exhibits robust tracking performance in the presence of motor parameter variations and load disturbances.     

基于左逆系统的无轴承异步电机无速度传感器运行

为了解决无轴承异步电机运行控制中转速检测的问题,实现对其高性能控制,提出了一种基于左逆系统的无速度传感器控制方法.建立了转速与转矩绕组定子电流的子系统,并证明了该子系统是左可逆的,将左逆系统与该子系统串联,便可实现对转速的观测.应用该方法建立了无轴承异步电机无速度传感器的矢量控制系统,并进行仿真研究.结果表明,该方法能在无轴承异步电机全速范围内准确观测出转速,实现无速度传感器方式的稳定悬浮运行.     

利用插入高频电流进行异步机转速辨识方法的研究

本文描述了一种异步电动机无速度传减速矢量控制系统转速辨识的新方法,它利用在ｄ轴插入的高频电流在矢量控制未完全解耦时产生的转矩纹波,估算转子磁链角速度。     

Linearizing control of induction motor based on networked control systems

A new approach to speed control of induction motors is developed by introducing networked control systems （NCSs） into the induction motor driving system. The control strategy is to stabilize and track the rotor speed of the induction motor when the network time delay occurs in the transport medium of network data. First, a feedback linearization method is used to achieve input-output linearization and decoupling control of the induction motor driving system based on rotor flux model, and then the characteristic of network data is analyzed in terms of the inherent network time delay. A networked control model of an induction motor is established. The sufficient condition of asymptotic stability for the networked induction motor driving system is given, and the state feedback controller is obtained by solving the linear matrix inequalities （LMIs）. Simulation results verify the efficiency of the proposed scheme.     

Sensorless speed control of PMSM via adaptive interconnected observer

In this article, a robust sensorless speed observer–controller scheme for a surface permanent magnet synchronous motor (PMSM) is proposed. First-of-all, following preliminary results in the framework of the induction motor that is less sensible to the position estimation error, an adaptive high gain interconnected observer is designed. It is only supplied by the electrical measurement: the motor currents and voltages. This observer estimates the rotor speed and position, the stator resistance and the load torque. A nonlinear backstepping controller is developed. The above observer is associated with this controller and the complete scheme practical stability proof is given. The overall system is tested by simulation in the framework of an industrial benchmark with a trajectory that particularly checks the motor unobservability condition. Some robustness tests have been carried out. The controller–observer scheme shows good performances in spite of the uncertainties and the unknown load torque.