Vector control strategies for single-phase induction motor drive systems

This paper discusses vector control strategies for single-phase motor drive systems operating with two windings. A model is proposed and used to derive control laws for single-phase motor drive systems. Such model is also employed to introduce the double-sequence controller. Simulation and experimental results are provided to illustrate the operation of the proposed drive systems.     

基于内模解耦控制的感应电机矢量控制系统

在感应电机矢量控制的基础上，针对于矢量变换后存在的交叉耦合电势，提出了一种基于内模控制的解耦方法，通过理论分析和基Matlab7．0下的仿真结果，深入地研究其解耦原理和性能。     

Position control of an induction machine using variable structure control

In this paper, a variable structure control algorithm is combined with an indirect field-oriented control strategy in order to control the position of an induction machine shaft submitted to large variations of mechanical configuration. The tracking capabilities and the robustness of the approach are tested experimentally using a low-cost DSP.     

A simple position-sensorless algorithm for rotor-sidefield-oriented control of wound-rotor induction machine

A simple position-sensorless method for the rotor-side field-oriented control of a wound-rotor induction machine is described in this paper. The algorithm is based on axis transformations. Compared to the previously proposed methods, it is more direct and the dependence on machine parameters is also largely reduced. The algorithm can be started on the fly without the knowledge of the initial rotor position. Operation at synchronous speed, corresponding to zero rotor frequency, is stable, thus making it suitable for variable speed constant frequency operations. Simulation and experimental results show excellent performance of the scheme     

The control of a synchronous machine using optimal control theory

The selection of stabilizing signals to improve power system dynamic behavior is presented. Some results from modern control theory are used to show how such stabilizing signals may be derived systematically for a turboalternator model connected through a double circuit line to an infinite bus. The closed-loop performance of this nonlinear system model with the derived linear optimal controller is then evaluated for a wide range of input disturbances and operating conditions which include three-phase fault studies with autoreclosure.     

Online identification of induction machine electrical parameters for vector control loop tuning

In a vector-controlled induction machine drive, accurate knowledge of the machine electrical parameters is required to ensure correct alignment of the stator current vector relative to the rotor flux vector, to decouple the fluxand torque-producing currents and to tune the current control loops. This paper presents a new method for online identification of the induction machine parameters required to tune a rotor-flux-oriented (RFO) vector control scheme. Accuracy of the slip frequency estimation required for RFO vector control is achieved by utilizing the parameter independent "flux pulse" rotor time constant estimation scheme, which utilizes short-duration pulses injected into the flux-producing current. The parameters required to tune the synchronous frame current control loops with a decoupling circuit are estimated using a recursive estimation scheme derived from the synchronous frame voltage equations. As the "flux pulse" scheme requires signal injection into the flux-producing current a new rotor time constant estimation scheme is presented, based on the sensitivity analysis of the recursive parameter estimation scheme. Simulation and experimental results are presented which demonstrate the effectiveness of the online parameter identification and control loop tuning technique.     

基于最优控制理论的配网自动化应用研究

在电力系统中应用最优控制理论可以对各种方案进行优化,从而使得电力系统的运行实现自动化、智能化发展.本文从最优控制理论出发对配网自动化的相关问题进行分析和探讨.     

Speed sensorless stator flux-oriented control of induction machine in the field weakening region

In a conventional speed sensorless stator flux-oriented (SFO) induction machine drive system, when the estimated speed is transformed into the sampled-data model using the first-forward difference approximation, a modeling error occurs in the sampled data model. As the result, an error in the rotor speed estimation is produced. The error included in sampled data model of the estimated speed is removed by the use of a digital low pass filter (LPF). However, the delay of the estimated speed occurs in transients due to the use of the LPF. Consequently, current control loss occurs at the transition to field weakening region by the delay of the estimated speed. This paper investigates the problem of a conventional speed sensorless SFO system produced by the delay of the estimated speed in the field weakening region. In addition, this paper proposes a new method to estimate exactly rotor speed by using a Kalman filter. The proposed method is verified by simulation and experiment.     

Modeling and simulation of induction machine vector control withrotor resistance identification

This paper shows that it is possible to use available commercial software to model and simulate a vector-controlled induction machine system. The components of a typical vector control system are introduced and methods given for incorporating these in the MATLAB/SIMULINK software package. The identification of rotor resistance is important in vector control, if high-performance torque control is needed, and modeling of the extended Kalman filter (EKF) algorithm for parameter identification is discussed. It is certainly advisable, when feasible, to precede implementation of new algorithms, whether for control or identification purposes, with an extensive simulation phase. Additionally, a technique for generating pulse-width modulation (PWM) phase commands to extend machine operation to higher speeds before field weakening occurs is simulated in a vector-controlled induction machine, driven by a PWM inverter. This demonstrates the versatility of the vector-controlled induction machine system model     

Simple direct torque control of induction machine using space vector modulation

A new method for direct torque control (DTC) based on load angle control is developed. The use of simple equations to obtain the control algorithm makes it easier to understand and implement. Fixed switching frequency and low torque ripple are obtained using space vector modulation, overcoming the most important drawbacks of classic DTC.     

基于热处理线淬火机控制策略的研究与应用

介绍了中厚板热处理线淬火设备组成、工艺概况和淬火自动控制系统,介绍了淬火模型的组成及控制策略,着重分析了加热温度和控冷速度对钢的淬透性和硬度等组织性能的影响,并在生产过程中不断优化完善淬后组织预测模型,大大增加NM360钢的强度、韧性,降低碳含量和碳当量。淬火后板材平直度及性能指标达到或优于国外同类进口先进设备的工艺水平,提高钢板的焊接性能,在热处理生产线上具有很高的推广价值。     

Field-oriented control of an induction machine in a high frequencylink power system

A field-oriented controlled induction machine drive operating with a high-frequency single-phase sinusoidal voltage link is presented. System performance is investigated by computer simulation and is verified by test on an actual prototype system. A control loop is proposed for minimizing the link-voltage fluctuation. The capability of rapid demagnetization of the induction machine by current regulation is investigated. A new current modulation technique called switch mode selection is proposed and its performance is compared with the conventional delta modulation technique     

Integrated starter generator for 42-V powernet using induction machine and direct torque control technique

This paper describes an integrated starter generator (ISG) for automobile applications with 42-V powernet. This system is based on an induction machine which is directly mounted on the engine crankshaft and controlled using the technique of direct torque control (DTC). The suitability of the technique for ISG application is explained. The control structure of DTC for ISG application is described. Detailed experimental results from a 1.4-1 diesel engine are presented demonstrating the performance of the system during cranking as well as generation. The ISG also incorporates the feature of "on the fly start" during generation mode. Details of a low voltage high current power converter developed for this application are also given.     

Variable-structure direct torque control - a class of fast and robust controllers for induction machine drives

A family of variable-structure controllers for induction machine drives is presented, in which the principles of direct torque control (DTC), variable-structure control (VSC), and space-vector pulsewidth modulation are combined to ensure high-performance operation, both in the steady state and under transient conditions. Three new VSC schemes are designed following the DTC voltage-control-based philosophy. These provide robust, fast, and accurate torque and flux control, without the penalty of high chattering. Comparative results demonstrate that proposed techniques preserve the DTC transient merits, while the steady-state behavior is significantly improved. Experimental results prove the strong robustness, accuracy, quickness, and low-ripple sensor-less operation of a drive that uses the new schemes.     

A new current model flux observer for wide speed range sensorless control of an induction machine

A new closed loop current model flux observer is designed to estimate the rotor flux, position and velocity of an induction machine. The current observer includes carefully designed sliding mode functions which are derivative of the fluxes along the /spl alpha/ and /spl beta/ axes. Therefore, when the estimated current converges to the measured one, the flux estimation is a mere integration of the sliding mode function. The rotor speed can then be derived from the sliding mode functions and the estimated flux. In the current and flux observers all of the terms that contain the rotor time constant and the rotor speed have been replaced by the sliding mode functions, thus making the proposed current and flux estimations completely insensitive to the rotor time constant variation and any error in the estimated speed. Simulations and experiments are performed under a variety of conditions to validate the effectiveness of the proposed algorithm.     

高速激光切割机床数控系统探究

随着经济的迅速发展,我国工业技术也有了较大的改善。现如今切割技术也有了很大的创新改进,新兴的激光切割,它目前已成为热切割技术发展的热点之一,激光切割技术相比较传统切割技术多了高精度、高效率、低污染等优点。为了满足激光切割装备的数字化、精密化等要求,实现此种技术的国产化。本文就高速激光切割机床数控系统各方面进行了研究分析,以此来满足我国对激光切割机床数控技术发展的要求。     

高速激光切割机床数控系统探究

随着经济的迅速发展,我国工业技术也有了较大的改善。现如今切割技术也有了很大的创新改进,新兴的激光切割,它目前已成为热切割技术发展的热点之一,激光切割技术相比较传统切割技术多了高精度、高效率、低污染等优点。为了满足激光切割装备的数字化、精密化等要求,实现此种技术的国产化。本文就高速激光切割机床数控系统各方面进行了研究分析,以此来满足我国对激光切割机床数控技术发展的要求。     

MATLAB在自动控制原理教学中的实践与应用

自动控制原理是电气专业一门重要专业核心课。具有概念抽象、数学含量大、计算繁杂等难点。利用仿真技术辅助教学有利于激发学生学习兴趣,在教学中引入MATLAB软件,设计教学项目,丰富课堂教学内容;设计实验项目,形成虚拟仿真和实操实验相结合的实践教学模式,提高学生学习积极性,达到良好的教学效果。     

Vector coupled-mode theory of dielectric waveguides

A consistent derivation of a system of vector coupled-mode (VCM) equations for parallel dielectric waveguides is presented and compared with earlier versions of the improved coupled-mode theory (ICMT). As a validity test, it is shown that the effectively scalar transverse electric and transverse magnetic (TM) coupled-mode (CM) equations are direct limits of our full VCM formulation. In particular, our formulation does not lead to the fundamental error found with earlier coupled-mode theories (CMTs) in a case of TM fields. Functional equations of our VCMT are consistent with Maxwell's equations and lead to higher precision. They can be applied to complicated arrays of strongly coupled parallel dielectric waveguides with true vectorial behavior.