Thrust control of a linear induction motor using magnetic field detection

A two-dimensional hybrid finite-element method is used to analyze the thrust response of a linear motor system in terms of vector control, using the air-gap flux as the input signal. A novel control scheme is used, in which the supply current leads the flux vector by 45°, obviating the need for circuit analysis that arises in the usual vector control scheme. The flux detection method is compared with the conventional average thrust control method and its effectiveness is evaluated.     

三电平扩展卡尔曼滤波异步电机滑模控制

传统异步电机闭环控制中转速和磁链外环采用比例积分(PI)控制,针对其有超调和动态响应慢等问题,提出了一种新型的滑模控制器用于外环转速和磁链控制,改善了动态性能.采用五阶扩展卡尔曼滤波(EKF)来估计转速和磁链并用于闭环反馈,进一步研究了引入转矩观测后的六阶EKF,考察了转动惯量对速度估计的影响,在三电平逆变器驱动异步电机平台上进行了各种实验.结果表明,基于EKF和滑模控制的无速度传感器控制系统在较宽的速度范围内具有良好的动静态性能.     

Speed sensorless vector control of induction motor using extendedKalman filter

A vector control of an induction motor by an estimated speed using an extended Kalman filter is proposed. With this method, the states are composed of stator current and rotor flux. The rotor speed is regarded as a parameter, and the composite states consist of the original states and the rotor speed. The extended Kalman filter is employed to identify the speed of an induction motor and rotor flux based on the measured quantities such as stator currents and DC link voltage. The estimated speed is used for vector control and overall speed control. Since the current control is performed at a synchronous rotating reference frame, the estimated speed information is also used for the reference frame transformation of the current controller. Computer simulations and experiments of the speed control have been carried out to test the usefulness of the speed estimation algorithm. The experimental results show that the performance of the speed estimation is very good     

压电马达模糊自校正PID控制方法研究

针对死区对压电马达系统带来的影响,采用“一维输入—三维输出”模糊推理机,设计了一种模糊自校正控制器,避免参数调整中的“耦合影响”。实验结果证实该控制器能够有效地抑制死区的影响,提高系统的控制精确度。     

Inertia-lowering control of induction motor

There are many requests for selecting freely the moment of inertia, even though the moment of inertia is determined by the materials, structure, shape, and size of the motors. From the standpoint of control, reducing the moment of inertia will make it possible to construct well-controlled drive systems and expand the applications in which a motor may be used to replace another nonelectric machine. An “inertia-lowering control” system has been developed that uses disturbance observer to reduce inertia. To realize this control system with vector-controlled induction motors, the equations and machine constants needed for designing the systems have been clarified. A digital signal processor and a microprocessor were adopted for induction motor control, and good results were obtained through the experiments.     

Scalar control systems for a traction induction motor

A brief review and comparative characteristics of scalar control systems for traction induction motors for using in the traction electric drive are presented. It is shown that, despite the obvious advantages of the systems of vector control and direct torque control, scalar control systems have found wide application. The operation features of scalar control systems with stability0 of absolute slip and a minimum of stator current are considered. Based on the equivalent circuit of an induction motor taking into account the stator and rotor iron loss, a comparative evaluation of the considered scalar control systems based on the criterion of the efficiency coefficient taking into account the temperature of the stator and rotor windings is presented. Simulation results in the MATLAB environment for an 11-kW induction motor are presented. It is established that scalar control systems operating under the principle of a stator current minimum have an advantage, as this maintains the desired torque value with higher values of efficiency coefficient, which decreases electromagnetic loads and power loss. It is shown that it is necessary to take into account the influence of windings temperature on the stator voltage and the parameters of the control system in connection with its affect on the minimum stator current and optimal absolute slip ensuring extremal control by current minimum.     

High-performance speed-sensorless control of an induction motor drive using a minimalist single-phase PWM converter

Home appliances and comfort conditioners are yet to benefit from the recent developments in power electronics because of cost constraints. In this paper, a speed-sensorless induction motor drive system using converters with reduced device counts (minimalist, sparse converters) and actuated from a single-phase system is proposed for such low-cost applications. The analysis, control, dynamic, and steady-state characteristics of the proposed drive are experimentally illustrated.     

感应电机控制策略综述

介绍了感应电机控制策略的发展,对转速开环恒压频比控制、磁场定向矢量控制、直接转矩控制、反馈线性化控制、滑模变结构控制与智能控制等控制策略进行了理论与实际运用的探讨,并分析了各种控制策略的优缺点,提出控制策略的发展方向。     

Analysis of the dynamic performance of a variable-frequency induction motor drive using various control structures and algorithms

A comparative analysis of the dynamic characteristics of field-oriented induction motor drive control systems relying on the main magnetic flux linkage vector reference, space-vector pulse width modulation (SVPWM) of the voltage inverter output, and direct torque control (DTC) is carried out using the Matlab/Simulink program package, with the parameters of the induction motor model used being the same. A changeover from stepless vector control systems to systems using microprocessors and modern controllable frequency converters operating on the principle of relay control entails possible changes in the properties of the electric drives being controlled. In this connection, there is a need to compare the dynamic performance characteristics of an electric drive with a slave vector control system (with an idealized frequency converter), referred to as electric drive 1 (ED1), an electric drive with a DTC system (ED2), and an electric drive using direct torque control and SVPWM (ED3). Modeling has shown that the response time of the torque control loop in all the control systems considered is the same, the time delay being no more than 0.01 s. On the whole, speed control transients in all of the above systems take their course in one and the same way. The differences in flux linkage control transients between ED2 and ED3, on the one hand, and ED1, on the other hand, are due to the differences between the methods used to form the electromagnetic torque. No provision is made in the above control systems for the stabilization of the magnitude of the flux linkage vector. At low loads, the flux linkage automatically follows the load. In an ED3 with direct torque control, the calculation of the necessary instant magnitudes of the voltage vector projections and the SVPWM based formation of the voltages applied to the motor allows implementation of a fast-response control system with minimal harmonic distortions and torque pulsations. The control system coefficients are calculated beforehand. The speed controller is adjusted to the technical optimum. In the main flux linkage oriented control system, it is also desirable to use an SVPWM-based formation of the motor voltage.     

Position sensorless control of interior permanent magnet synchronous motor using extended electromotive force

Driving a permanent magnet synchronous motor (PMSM) requires the rotor position information to control the motor torque, and this is generally detected by mechanical position sensors such as an encoder or a resolver. However, these sensors increase the machine size and the cost of the drive, and reduce reliability of the system. Therefore, many papers about position sensorless drive method of PMSM have been published. This paper presents a position sensorless control of interior permanent magnet synchronous motor (IPMSM). A mathematical model of IPMSM using the extended electromotive force (EMF) in the rotating reference frame is utilized to estimate the rotor speed and position. This model has a simple structure integrating position information into the extended EMF term. Therefore, the sensorless control based on the mathematical motor model can be implemented simply. The estimation method proposed is based on the principle that the error of the current is proportional to that of extended EMF. This method was carried out using a 6‐pole, 400‐W, 1750 r/min test motor system. It was found that sensorless speed control was achieved from 80 r/min to 1800 r/min under 0 to 100%loads. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 161(3): 41–48, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20406     

Direct-drive induction motors: using an induction motor as an alternative to a motor with reducer

This article presents the performance and size comparisons of direct-drive induction motors with gearbox-driven systems. Three different low-speed applications with output speeds to the driven equipment ranging from 300-600 r/min is reviewed. In addition, permanent-magnet (PM) motor advantages and disadvantages are also discussed.     

Sensor-less speed control of an induction motor

Vector control systems of induction motors without speed sensors have been earnestly developed to obtain a simple construction. To estimate the rotor speed, these systems require information of machine parameters such as secondary resistance. Therefore their performance is sensitive to variations of secondary winding temperature. The authors propose two useful calculation methods for a speed sensorless system. The first is a rotor speed calculation method by which the exact speed can be computed directly. The method does not require information of the secondary resistance, which makes it free from variations of secondary resistance. The second is a direct secondary resistance calculation method. It can be applied to compensation in speed sensorless vector control for exact speed estimation of secondary resistance. The effectiveness of the proposed methods are verified by digital simulation and experimental results. In this article, the influence of the machine and control circuit parameters are also examined     

感应电机非线性反馈补偿控制

针对含有不确定项非线性系统的控制问题,依据Lyapunov理论,提出了具有参数不确定性的一类非线性系统的鲁棒稳定和跟踪控制算法,将系统的数学模型分解为标称子系统和不确定子系统,设计非线性反馈补偿控制律实现预期的控制目标,并将该算法应用到转子磁场定向的感应电机控制中,以解决转子电阻时变且难以测量、不确定性会影响到电机的动态性能问题。通过仿真验证了设计方法的可行性,能够保证即使在转子电阻偏离其标称值时,转子磁链和转子转速具有稳定跟踪性能。     

Sensorless control of inverter-fed induction motor drives

Sensorless control is considered to be a lower cost alternative than the position or speed encoder-based control of induction motors. Two popular sensorless control methods, namely, the model reference adaptive system (MRAS) and the Luenberger observer (LO) methods are compared for speed and torque control characteristics. They are also compared against the well-known vector control principle. For the drive system simulated, the torque and speed obtained from sensorless control are almost identical to those obtained from the vector control method. However, the torque ripple for the sensorless methods is observed to be higher than vector control-based method. The MRAS method introduces higher torque ripple when compared to the Luenberger observer. In addition, speed estimation methods employed in sensorless control are more sensitive to motor parameter variations.     

交流感应电机的SVPWM控制技术

介绍SVPWM技术，给出了基于TMS320F240软件决定切换模式的交流感应电机的控制方法，证明该法在三相电压源逆变器中能产生更少的谐波、并减少损耗。     

一种无差拍直接转矩控制方法

针对现有的感应电动机无差拍直接转矩控制方法计算比较复杂,且计算得到的两个控制电压与控制对象磁链和转矩不是一一对应的问题,提出了一种在定子磁场定向的同步旋转坐标系下进行无差拍直接转矩控制计算方法.由d轴磁链方程推导出磁链无差拍控制电压的计算式;利用和定子磁链相垂直的q轴电流方程,推导出转矩控制电压计算式.计算出的电压矢量由空间电压矢量脉宽调制方法实现.这种方法计算简单,不需要解二次方程,分离的磁链和转矩控制计算有利于控制安排.对采用这种方法的直接转矩控制系统进行仿真表明,系统转矩控制和磁链控制响应快,对参数的变化不敏感.     

感应电机直接转矩控制系统

为了确定影响感应电机直接转矩控制系统稳态性能的主要因素,使用自己开发的仿真软件包进行了仿真实验分析,指出了定子电阻、磁链滞环容差和转矩滞环容差是影响感应电机直接转矩控制系统性能的三个主要因素.定子电阻主要对磁链轨迹影响较大,磁链滞环容差和转矩滞环容差主要影响定子电流谐波和电机转矩,并提出了一些补偿措施.这些结论为进一步改进系统性能提供了一些依据.     

Robust vector control of induction motor without using stator androtor circuit time constants

To solve the problem of performance degradation due to parameter variations in an indirect vector control of an induction motor, a novel and simple estimation method for the rotor circuit time constant is presented. The proposed method is based on regulating the energy stored in the magnetizing inductance, which can be calculated from the terminal voltages and currents. From theoretical and experimental results, it is verified that the proposed method can overcome the problem of performance degradation due to parameter variations without the necessity of knowing the values of stator resistance and rotor circuit time constant at all