考虑横向电流和饱和轴向变化的双斜槽转子感应电机起动转矩分析

双斜槽转子感应电机是一种能提升普通单斜槽转子感应电机性能的新型电机,横向电流和磁场饱和轴向变化对其起动性能的影响未得到充分研究。为了精确计算双斜槽转子感应电机的起动转矩,基于三维有限元瞬态场,本文建立一种考虑横向电流和磁场饱和轴向变化的双斜槽转子感应电机分析模型。提出一种考虑主电抗变化的等效电路参数法,精确计算双斜槽转子感应电机的起动转矩特性。同时通过分析气隙磁通密度的轴向变化来说明三维有限元分析模型能考虑磁场饱和轴向变化,通过仿真不同横向电阻值的有限元模型来探究横向电阻与转矩-转速曲线的关系。与有限元中的虚位移法和实验相比,计算结果证明了所提方法能够精确计算双斜槽转子感应电机的起动转矩。     

电动车用感应电机磁场定向矢量控制研究

电动车用感应电机参数变化易引起电机振荡现象，文中以含微分运算的三相感应电机模型为基础，提出了一种具有转差频率控制的转子磁场定向矢量控制方法，给出了相关的理论推导及实验结果。该方法能够有效地抑制由于电机参数变化过大导致的电机振荡现象，能使电机可靠地运行于弱磁区域，可满足高功率密度、高转速电动车用感应电机的控制要求。实验结果验证了该方法的正确性及有效性。     

转子电阻未知时感应电动机间接磁场定向控制

转子电阻准确已知是感应电动机间接磁场定向控制获得良好性能的关键,但在电机运行过程中,转子电阻却是时变的.为此,本文从转子磁链调节的稳态过程出发,根据转子电阻与转子磁链、电磁转矩之间的关系,设计了一个新型的转子电阻估计器.该估计器形式简单,计算量小,能极大改善感应电动机间接磁场定向控制对转子电阻变化的鲁棒性.对感应电动机的仿真结果表明,上述估计算法是有效的.     

考虑低速稳定性的感应电机转子磁场定向校正策略

感应电机的转子磁场定向控制中,磁场定向角的准确性影响着电机的转矩输出性能。在速度测量准确的场合,转子定向角主要受转子电阻误差的影响,而转子电阻校正又受到定子电阻误差的影响。目前,较少的论文对转子电阻和定子电阻同时进行补偿,且同时补偿下的稳定性问题也鲜有研究。该文提供了一种新型的基于MRAS的转子电阻和定子电阻补偿策略,经李雅普诺夫稳定性理论验证,该策略可以保证系统在低速下的稳定性。经5.5 kW试验平台验证,该策略可以有效提升转子磁场定向控制在低速下的转矩输出性能。     

异步电机转子时间常数的补偿方法

在异步电机转差频率矢量控制系统中,通常采用固定的转子时间常数进行转差频率计算,由此存在电机参数不准确而造成磁场定位不准的问题。提出了一种转子时间常数的补偿方法,采用模型自适应法将电机转子参数对控制系统的影响降为最小。实验结果表明,与常规的转差频率矢量控制方法相比,该方法能更有效地控制电机电流,并对转子参数的变化具有很强的鲁棒性。     

基于转子磁链q轴分量的异步电机间接矢量控制转差频率校正

异步电机间接矢量控制系统在工业场合应用广泛,然而其性能易受转子电阻参数变化等因素影响。该文将定子电流矢量定向同步坐标系下的转子磁链观测器与间接矢量控制系统相结合,利用观测器得到的实际磁链计算转子磁场定向下转子磁链的q轴分量,并根据定向准确情况下转子磁链q轴分量为零的特点提出一种间接矢量控制转差频率校正方法,保证间接矢量控制系统对转子磁场的准确定向。详细介绍了该校正方法的基本原理和系统框图,并进行了稳定性分析。仿真和实验结果证明了该校正方法的有效性。     

矢量控制中感应电动机转子电阻的自适应辨识

异步电动机的转子电阻在电机运行中由于温升、集肤效应等原因 ,往往是电机控制系统中变化最为明显的参数之一。如何准确、快速的辨识异步电动机转子电阻 ,以提高整个矢量控制系统的鲁棒性 ,一直以来是国内外研究的重点。转子电阻对异步电动机调速系统的影响由于控制策略和控制结构的不同而有所差别。本文在异步电动机矢量控制系统中提出了一种基于转子磁场定向的转子电阻自适应辨识方法。这种方法结构简单 ,计算量少 ,而且仿真和实验结果证明这种方法可以准确、快速的辨识转子电阻。     

异步牵引电机冷热态转矩控制策略

机车牵引变流器和电机的组合试验中,电机的冷热态转矩特性是调试的难点和重点。基于转子磁链定向的间接矢量控制理论,分析了电机牵引/制动工况下电机冷热态转矩输出变化的原因,提出了全速度范围内补偿转差频率的方法。经过试验验证,该方法能够减小牵引电机冷热态输出转矩的偏差,有效提高牵引系统的控制性能。     

改进电压模型的感应电机MRAC无传感器控制

以电压模型为参考计算转子磁链矢量的感应电机模型参考自适应控制(MRAC)转速观测器的性能受到电压模型对直流偏移和低速下对定子电阻敏感性的影响。针对这两个因素,通过引入复增益和变截止频率低通滤波器得到了无直流偏移的等效电压模型,并提出了基于转子反电动势矢量的MRAC定子电阻在线辨识方法。搭建了感应电机直接磁场定向无速度传感器控制系统,通过实验证明了所提方法的正确性与可行性。     

变压恒频感应电机效率功率因数优化控制

针对感应电机在低负载率和宽转速区间内效率和功率因数指标发生矛盾的问题,以鼠笼式感应电机作为研究对象,采用动态解耦法构建了电机效率和功率因数指标函数,运用凸集理论证明指标函数在转子频率和转差频率平面内存在最优点,提出将恒频作为约束条件,通过优化指标函数来获得最佳工作点信息的思想.定子电阻温升的参数摄动会影响寻优结果,提出利用人工神经网络减小参数摄动影响,并获得参考指标函数从而调整转速调节器的参数的方法.仿真结果说明上述方法能够实现有参数摄动情况的优化,使电机的指标函数逼近最佳运行点的指标.实验结果表明,优化方法能为控制系统设计提供支持,通过改变功率因数实现节能目的.     

感应电动机系统的变结构反推控制研究

感应电动机系统的矢量控制为了进行电流(或电压)的3/2(或2/3)坐标变换需要进行转子转差或磁链角的计算，转子转差的计算容易受转子电阻变化的影响，而磁链角的直接计算容易受定子电阻变化的影响，因此避免转子转差或磁链角的计算对于感应电动机系统的控制是非常有意义的。文中把变结构反推控制运用于感应电动机系统的转矩和磁链控制，设计方法避开了转子转差或转子磁链角的计算，通过一定的坐标变换，基于定子侧的静止坐标系实现转矩和磁链的解耦控制。变结构反推控制设计能够实现快速的速度、转矩和磁链的渐近跟踪，同时系统控制器能够保证系统性能在电动机参数和外部负载变化时具有强的鲁棒性，通过Matlab仿真验证了系统设计的有效性和可行性。     

对转子电阻变化自适应的高性能转差型矢量控制系统

本文分析了感应电动机转子电阻变化对转差型矢量控制系统动、静态性能的影响,提出一种结构简单的转子电阻在线辨识算法,并以8086微处理器构成离散模型参考自适应系统,对转子电阻进行实时校正。实验结果表明,系统能迅速补偿转子电阻的变化,使感应电动机电磁转矩系数基本保持恒定。     

Modeling and implementation of a microprocessor-based CSI-fedinduction motor drive using field-oriented control

A new approach to model the current-source-inverter-fed induction motor drive is presented. The mathematical model takes into account the rectifier, inverter, and induction motor dynamics and is established in the stationary reference frame. For controlling the drive speed, a modified indirect field-oriented control is proposed. To counter the effects of torque pulsations at very low speeds and rotor resistance variation, a slip compensation loop is included in the control law formulation. A microprocessor-based prototype system is also implemented, providing full digital control of the drive speed. Both computer simulation and experimental results are presented     

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.     

Online tuning method of stator and rotor resistances in both motoring and regenerating operations for vector‐controlled induction machines

The vector control of induction motors is widely used. This method needs accurate motor parameter but the stator and rotor resistance vary due to motor temperature variation. If the value of resistance in the controller can be set up accurately at first, there must be a difference between the reference and real value of torque because of drift of the resistance. It is necessary to adapt the resistance value. The indirect field‐oriented control of an induction motor requires the value of rotor resistance only, but the direct field‐oriented control method with rotor flux observer requires the value of not only rotor resistance but also stator resistance in the controller. Consequently, it is necessary to adapt both stator resistance and rotor resistance. A parameter adaptation scheme has previously been proposed for the direct field‐oriented control method with rotor flux observer, but this method cannot be used when the motor is in regenerating operation. In this paper, a new stator and rotor resistance adaptation scheme is proposed, which can be applied when the motor is in regenerating operation. The usefulness of the proposed adaptation scheme is confirmed by simulation. © 2001 Scripta Technica, Electr Eng Jpn, 135(1): 56–64, 2001     

异步电动机间接转矩控制系统的效率优化设计

针对异步电动机间接转矩控制系统,提出了一种效率优化方法.首先,在计及铁损的情况下推导了异步电动机的损失模型;然后,在旋转坐标系下,计算出最优的转差率,根据转差率与转子磁链及电磁转矩的函数关系,推导出最优的转子磁链,根据定子磁链与转子磁链、电磁转矩之间的函数关系,得到定子磁链的最优给定值;最后,将所得到的最优定子磁链给定量用于异步电动机间接转矩控制系统中.实验验证了方法的有效性.     

Rotor resistance adaptation for sensorless vector-controlled induction machines

The vector control method is widely used for induction motor drives. In these applications, a rotational transducer such as a shaft encoder is used. A rotational transducer, however, cannot be mounted in some cases, such as motor drives in a hostile environment or high-speed motor drives. Several sensorless vector-controlled induction machine drive methods have been proposed. These methods have the disadvantage that rotor resistance variation causes errors in the estimation of the motor speed. It is difficult to estimate the motor speed and the rotor resistance simultaneously, because the equivalent rotor resistance is the ratio of the rotor resistance to the slip at steady state. Therefore, we have proposed a method of simultaneously estimating the motor speed and the rotor resistance of an induction motor by superimposing ac components on the field current command. This paper presents a modified method of the rotor resistance adaptation. The validity of the proposed method is verified by experiments. © 1998 Scripta Technica, Electr Eng Jpn, 125(2): 65–72, 1998     

感应电动机负荷参数对暂态电压稳定性的影响

以简单电力系统为研究对象,采用考虑机电暂态过程的三阶感应电动机负荷模型,通过时域仿真分析了输电线路电抗、负荷母线并联补偿容抗和感应电动机负荷参数的变化对电力系统暂态电压稳定极限切除时间的影响。分析结果表明:上述参数对电力系统暂态电压稳定性都有影响,其中,输电线路电抗、感应电动机负荷的比例、定子电抗、转子电阻、转子电抗、转子初始滑差等参数对电力系统暂态电压稳定性的影响较大。     

The influence of mistuned motor parameters on vector control performance and on line slip frequency correction strategy for induction machine operated under one‐pulse PWM mode

In high‐power, high‐speed traction drive systems, the traction motor usually operates under one‐pulse PWM (pulse width modulation) mode (square wave) during high‐speed operation. The constant output voltage in this condition makes the traditional vector control inoperative anymore. In this paper, a modified vector control strategy using open‐loop current control instead of closed‐loop current control is proposed. The modified control strategy is specially designed for an induction motor operating under one‐pulse PWM mode. As the field orientation is greatly affected by the deviation in the parameters, the influence of mistuned rotor time constant and mutual inductance (which are regarded as the most important parameters for field orientation) on the performance of modified vector control is studied comprehensively, including the influence on estimated angle and amplitude of rotor flux, d/q‐axis voltage, and output torque. Subsequently, based on the comparison between the different methods, a new slip frequency correction strategy is proposed to maintain proper field orientation for the modified vector control. The new correction strategy is based on the q‐axis current component error. It is independent of the motor parameters and can be easily realized through minor calculations. The simulation and experimental results show that the proposed slip frequency correction strategy can not only eliminate rotor flux angle error in steady state but also effect rapid torque response during the transient process under one‐pulse PWM mode. © 2014 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

一种新颖的感应电动机控制仿真研究

矢量控制是基于旋转坐标实现感应电动机的交、直轴电流的解耦控制,状态变换需要计算转子转差或转子磁链角的位置.提出了一种新颖的感应电动机解耦控制方案,该设计方法可以实现快速的转速、转矩和磁链的跟踪.与传统控制方法相比,该方法避免了转子转差或转子磁链角位置的计算.仿真结果证明了该设计方法的有效性.