A Simple Control System for Current Source Inverter-Fed Induction Motor Drives

A simple control system for induction motor drives with the current source inverter is presented. This system is based on the idea of field-orientated control. In contrast to well-known ways of realization a torque proportional quantity is calculated from stator voltage and current without explicit flux calculation or integration. A speed sensor is not required. The theoretical principles of this method are discussed. Some transients which illustrate the performance of some different system variants are presented.     

Analysis of PWM GTO Current Source Inverter-Fed Induction Motor Drive System

A GTO current source inverter which consists of six main GTO's, two auxiliary GTO's, and three capacitors is presented. This inverter can supply both the sinusoidal voltage and current to the motor by pulsewidth modulation (PWM) techniques. The normal PWM pattern produced by two control signals with the carrier and the modulating waves and the optimal PWM pattern determined by the harmonic analysis are described. The experimental waveforms for 2.2-kW induction motor drives are given and the circuit operation of this inverter in the PWM technique is clearly shown. In addition, the steady-state characteristics of this inverter-induction motor drive system are analyzed by the state-variable methods, and a close agreement between the analyzed and the experimental waveforms is obtained. It is shown that the harmonic components are eliminated or reduced by using the optimal PWM pattern, and the new inverter with sinusoidal current and voltage is very excellent for ac motor drive.     

变频调速异步电动机效率优化控制的研究进展

异步电动机运行于额定工作点附近时效率较高,轻载运行时其效率会明显下降.优化变频调速异步电动机的效率对于节约能源、系统自身冷却和控制环境污染具有重要意义.总结近年来变频调速异步电动机效率优化控制策略的研究现状,包括基于模型的最优励磁控制、最小输入功率在线搜索法和最小定子电流控制等,分析了各种效率优化控制策略的性能和优缺点,指出变频调速异步电机效率优化研究的发展方向,并给出考虑电机动态响应的效率优化控制研究结果.     

通用变频器-感应电机系统的电机耗能型制动控制方法

利用感应电动机内部损耗进行制动的方法受到了越来越多的重视,本文分析了该方案的数学模型,提出了物理实现的约束条件和具体的控制方案.仿真和实验结果表明采用该控制算法可以有效的对电机进行快速制动,同时由转子侧回馈的能量几乎全部消耗在电机的定转子电阻上,使系统在满足功.能要求的同时,能够一直处于安全的工作状态.该方法可用于各种需要快速制动的"通用变频器 感应电机"系统.     

Control Characteristics of Inverter-Fed Induction Motor

Efficient use of an inverter-fed induction motor drive necessitates a knowledge of the characteristics of the induction motor from a " control" point of view. The characteristics of both the voltage -and the current-source inverter-fed induction motor drive are investigated, neglecting the filter time constants in the link and feedback loops. Of particular interest is the role played by the voltage/current and frequency inputs. Their effects on variables that are not often discussed such as torque angle, stator real power, airgap flux- linkages and stator and rotor voltages/currents are studied. A by- product of this aspect of the study leads to the nature of feedback signals and their suitability for control purposes. It is also found that the link filter has little effect on relative suitability of these signals. A study of the current source induction motor drive dynamics for torque angle feedback is included.     

A Method of Sensing Line Voltages for Parameter Adaptation of Inverter-Fed Induction Motor Servo Drives

Most high-performance inverter-fed induction motor drive systems require signals corresponding to the input voltages of the motor for parameter adaptation. Low-performance systems require the signals for stabilization. The voltage signals are used in the controller circuit and therefore require isolation. Isolation of the voltage signals is not a cost-effective solution in low-power motor drive systems. The fact that the base drive signals to the transistor inverter are isolated makes them the ideal choice for the reconstruction of the motor line voltages. A method of sensing line voltages from the base drive signals of the transistor inverter circuit is described. A step-by-step derivation of the voltage sensing algorithm is given which leads to a simple realization. The synthesized voltages are used in parameter adaptation for inverter-fed induction motor drives. The sensing scheme has been implemented on a laboratory prototype, providing experimental results which are presented.     

Current Controller for Autocommissioned Vector-Controlled Induction Motor Drives

A current controller composed of a current regulator associated to a parameter adaptation scheme is proposed. The current regulator considers the inherent coupled structure of the induction machine. The adaptive block is coupled to this regulator in order to carry out a high performance current control with low sensitivity to parameter variations. It is shown that this controller can also be used to estimate the machine saturation characteristic and the rotor time constant as part of an indirect vector control autocommissioning procedure. A discrete time approach is utilized for the design considering microprocessor implementation.     

两相逆变器—感应电动机系统的分析及动态性能模拟

本文介绍了最新开发、适用于汽车蓄电池及太阳能电池供电的两相逆变器—感应电动系统。文章讨论了系统构成特点,以及与永磁直流电动机和无刷直流电动机相比所具有的优点。文章把两相逆变器和两相感应电动机作为一个整体列举了系统的数学模型,根据编制的计算机程序可以模拟系统的动态及稳态性能,与研究样机实测性能对比两者较为接近。     

Power Line Communication in Motor Cables of Inverter-Fed Electric Drives

It has been shown that an inverter-fed power line is a feasible medium for the transmission of modulated information. The communication channel includes the feeder cable terminated by two loads: the motor and the inverter. This link is a suitable alternative for the sensor cabling between motors and inverters in motor control and diagnostic applications. The use of the motor power cable in the speed feedback induction motor control application and the modelling of the formed communication channel are presented and discussed in this paper.     

DC Link Filter Design Considerations in Three-Phase Voltage Source Inverter-Fed Induction Motor Drive System

The dc link filter elements in a three-phase voltage source inverter-fed induction motor system can affect the performance of the drive system if not properly chosen. The requirements, design considerations, and a simplified procedure for the selection of filter component values based on minimization of voltage and current ripple currents in the dc link, damping effects, and on resonant frequency considerations are formulated. Typical computational results and experimental waveforms are presented.     

Principle of a Dual Current Source Converter for AC Motor Drives

The principle of operation of a dual current source converter is briefly explained. The combination of two single current source converters (SCSC) to form a ``dual (duplex) current source converter' (DCSC) is proposed. The DCSC is shown to have the following merits: 1) it retains all the advantages of the SCSC; 2) it reduces the harmonic content of the current waveform considerably; and 3) since the load current is shared equally between two current source converters, ratings of the individual components employed in the circuit are considerably lowered. A DCSC can be an attractive choice for sophisticated large horsepower drives where a good performance of the drive rather than cost is a prime factor. An open-loop control scheme employing the DCSC for an ac motor drive has been successfully implemented in the laboratory. Oscillograms of the improved load current waveforms are shown.     

Integral Variable Structure Controller for Current Control of PWM Inverter-Fed AC Drives

A new current control technique is presented for three-phase PWM inverterfed AC drives. The features of several existing approaches are analyzed and an integral variable structure control (IVSC) is proposed as an effective way of realizing the high-performance current control. The characteristics of the proposed IVSC are investigated and the design method is presented for the AC drives associated with a voltage-fed PWM inverter. By employing the proposed control, a robust control performance against the parameter uncertainties is obtained in both transient and steady states. The proposed control is applied to the three-phase induction motor drives and the performance improvement is well demonstrated through the simulations and experiments.     

Theoretical and Experimental Analysis of a Two-Phase Inverter-Fed Induction Motor

A variable-speed squirrel-cage induction motor is described. The speed variation is obtained by means of a two-phase inverter that contains four thyristors only. Both experimental and theoretical results are presented.     

The Stator Voltage-Controlled Current Source Inverter Induction Motor Drive

The steady-state and dynamic performance of a stator voltage-controlled current source inverter (CSI) induction motor drive are presented. Commutation effects are neglected and the analytical results are based on the fundamental component. A synchronously rotating reference frame linearized model in terms of a set of nondimensional parameters, based on the rotor transient time constant, is developed. It is shown that the control scheme is capable of stabilizing the drive over a region identical to the statically stable region of a conventional voltage-fed induction motor. A simple approximate expression for the drive dominant poles under no-load conditions and graphical representations of the drive dynamics under load conditions are presented. The effect of parameter variations on the drive dynamic response can be evaluated from these results. An analog simulation of the drive is developed, and the results confirm the small signal analysis of the drive system. In addition the steady-state results of the analog simulation are compared with experimental results, as well as with corresponding values obtained from a stator referred equivalent circuit. The comparison indicates good correspondence under load conditions and the limitation of applying the equivalent circuit for no-load conditions without proper recognition of the system losses.     

Direct Torque and Flux Control of a Four-Switch Three-Phase Inverter-Fed Synchronous Reluctance Motor Drives

This paper presents an application of direct torque and flux control (DTFC) for a four-switch three-phase inverter (FSTPI)-fed synchronous reluctance motor (SynRM) in which the saturation and iron losses' effects are involved in the machine control modeling. The DTFC switching technique for the SynRM fed by FSTPI in low-power and low-cost applications is implemented by imitating the six-switch three-phase inverter (SSTPI). By considering equal effective vectors depicted in SSTPI, the αβ stationary reference frame is represented by using six sectors. Similarly, the voltage space vector formation is constructed in FSTPI. Accordingly the SynRM performance under DTFC is precisely analyzed by considering the saturation and iron losses' effects. The DTFC behavior based on SSTPI- and FSTPI-fed SynRM is evaluated using Simulink benchmark. At different operating conditions, further simulation and experimental results of DTFC based on FSTPI dynamically confirm the effectiveness of the proposed control application on the SynRM.     

Nonlinear Adaptive Control of an Inverter-Fed Induction Motor Linear Load Case

An adaptive nonlinear control system for an inverter-fed induction motor is presented. The approach taken is fundamentally different from previous work on induction motor control in that the aim is to control shaft speed directly. Further, the inverter control variables, frequency and-voltage, are related via the steady-state model to the shaft speed and motor current. By making the controller adaptive, neither load nor machine parameters need be specified, although in practice the, latter are usually available from the machine manufacturer, and, of course, full use can be made of this knowledge.     

感应电机电流环非线性积分滑模控制策略

滑模控制器能有效提升感应电机电流环鲁棒性,然而传统滑模控制存在严重的抖振问题,虽然通过引入趋近律能有效降低系统抖振,但仍无法实现系统在有限时间内收敛.为此,该文提出一种感应电机非线性积分滑模电流控制器,在削弱系统抖振的同时,实现了定子电流误差在有限时间内收敛.首先,设计非线性积分滑模面,有效避免了传统积分滑模面中初始误...     

Study of Parameter Sensitivity in High-Performance Inverter-Fed Induction Motor Drive Systems

Vector control schemes are used in inverter-fed induction motor drives to obtain high performance. Crucial to the success of the vector control scheme is the knowledge of the instantaneous position of the rotor flux. The position of the rotor flux is measured in the direct scheme and estimated in the indirect schemes. Since the estimation of the flux position requires a priori knowledge of the induction motor parameters, the indirect schemes are all machine-parameter dependent. Changes in temperature and saturation levels of the machine vary the machine parameters and, hence, indirectly influence both the steady state and the dynamic operation of the drive system. Analytic expressions are derived to evaluate the effects due to parameter sensitivity. The simulation is experimentally verified on a drive system.