异步电机按定子磁场定向的转差频率控制

在分析现有转差频率控制方案优缺点的基础上，提出一种按定子磁场定向的转差频率控制方案。利用坐标变换和磁场定向原理，建立按定子磁场定向的异步电机数学模型。新系统通过定子电压直轴分量直接控制定子磁链的变化率；在转速通道中，电流调节器的输出作为转差频率，继承了标量型转差频率控制方案的优点。新系统的动态控制算法不依赖于转子电阻和电感参数。结果表明，新系统具有良好的静、动态性能和鲁性棒。     

基于转差频率矢量控制的异步电动机动态性能仿真

本文以异步电动机的转差频率矢量控制调速系统为研究目标,介绍矢量控制的思想和转差频率控制原理,并通过Simulink建立仿真模型,观测异步电动机起动和突加载时的输出转速、转矩、定转子磁链等参数,验证转差频率矢量控制策略的仿真效果,分析了异步电动机的动态性能。仿真结果表明转差频率矢量控制策略具有良好动态性能。     

感应电机转差变频调速系统的稳态矢量控制方法

利用空间矢量分析了一般的感应电机转差频率控制系统，并在其中引入矢量控制的思想，从而提出了一种新的电流控制策略，使系统获得了准矢量控制的效果，并引入了动态相位补偿，以期获得更好的动态性能。     

三电平异步电机的无速度传感器矢量控制系统研究

为解决在中高压领域无速度传感器矢量控制速度辨识差的缺点,基于三电平电压源型逆变器,提出了一种异步电机无速度传感器矢量控制方案.该方案采用间接矢量控制(IFOC)策略,以模型参考自适应(MRAS)方法构造速度辨识系统,并在新型三电平空间矢量脉宽调制(SVPWM)简化算法基础上,运用MATLAB/Simulink实现对三电平异步电机无速度传感器矢量控制系统的仿真研究.仿真结果表明,所述控制方法正确有效,该系统具有较好的稳态特性和动态响应能力.     

基于Simulink的转差频率矢量控制的建模和仿真

直接转子磁场定向矢量控制系统较为复杂、磁链反馈信号不易获取,而转差频率矢量控制方法是按转子磁链定向的间接矢量控制系统,不需要进行磁通检测和坐标变换。在分析其控制原理的基础上,应用Simulink仿真平台构建了转差频率矢量控制的异步电机调速系统仿真模型,对其进行了仿真分析。仿真结果验证了,采用转差频率矢量控制的调速系统具有良好的控制性能。     

基于Matlab的异步电动机间接矢量控制系统研究

交流电机高性能调速系统中,间接矢量控制系统控制方法比较简单,不需要进行磁通检测,而像通常的转差控制方法一样,只要测出电动机转子频率,加上根据需要的转矩推算出应有的转差频率,以此控制定子电流的瞬时频率,就能使电动机的电流和转矩迅速由原先的工作状态变到新的所需工作状态。本文利用Matlab/Simulink对间接矢量控制系统进行研究,结果表明系统稳定,并具有较好的静动态性能。     

带电阻参数估计的异步电动机转差频率矢量控制

采用电压前馈控制与电流反馈控制相结合实现异步电动机定,转子电阻参数估计,提出了带电阻参数估计的电压控制型异步电动机转差频率矢量控制的一种实现方案,计算机仿真和实验结果表明,该控制方案具有较好的参数估计和转子磁链控制效果。     

同步电动机转矩角矢量控制原理

通过分析异步电动机转差频率矢量控制的特点,阐述了异步电动机转差频率和同步电动机转矩角之间的本质联系.类比于异步电动机转差频率矢量控制原理,提出了同步电动机转矩角矢量控制原理.该原理适用于控制精度要求不太高的同步电动机的控制系统,具有较高的性能价格比.     

sf型矢量控制系统参数变化对系统控制性能的影响分析和补偿方法

转差频率(sf)型矢量控制系统是一种较为实用的矢量控制系统。但由于该系统是磁通开环控制的,因此,系统动、静态性能对参数变化较敏感。本文着力定量分析并验证了参数变化对系统性能的影响,提出了系统中关键性参数 K_s (转差增益)的整定及补偿方法。本文是以电流源型逆变器进行系统试验的。     

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。     

A generalized method of controlled voltage source-fed induction motor vector control using the observer theory

Vector control of induction motors is widely used for industrial applications. On-line parameter identification and speed sensorless control are being studied actively. A representative method for these problems is the application of an adaptive full-order observer. The rotor flux for vector control is estimated by a full-order observer and machine parameters, or the rotor speed is determined by an adaptive algorithm. In this paper, a new vector control scheme with parameter identification is proposed. This method is based on the adaptive full-order observer. However, the observed currents which are usually estimated in the voltage model are considered as command currents and the voltage model is used for the current controller. As a result, the proposed system is simpler than the conventional adaptive full-order observer system. Since the proposed system is composed of an induction motor model in a synchronously rotating reference frame, the well-known slip frequency control block is contained. The arrangement of the poles which are related to the torque transfer function is discussed. A linear model is derived taking into account the effects of the change of the stator and rotor resistances. The trajectories of poles and zeros of the torque transfer function are computed and discussed for various system parameters. Identification of stator and rotor resistances is confirmed by simulation using a nonlinear system model. The proposed idea is applied to a speed sensorless system; this system has a similar configuration to those of existing systems under some assumptions. © 1997 Scripta Technica, Inc. Electr Eng Jpn, 119(4): 66–76, 1997     

Modified direct torque control method for induction motor drives based on amplitude and angle control of stator flux

This paper proposes design and implementation of a direct torque controlled induction motor drive system. The method is based on control of separation between amplitude and angle of reference stator flux for determining reference stator voltage vector in generating PWM output voltage for induction motors. The objective is to reduce electromagnetic torque ripple and stator flux droop which result in a decrease in current distortion in steady-state condition. In addition, the proposed technique provides simplicity of a control system. The direct torque control is based on the relationship between instantaneous slip angular frequency and rotor angular frequency in adjustment of the reference stator flux angle. The amplitude of the reference stator flux is always kept constant at rated value. The system has been implemented to verify its capability such as torque and stator flux responses, stator phase current distortion both during dynamic and steady state with load variation, and low speed operation.     

An Approach to Flux Control of Induction Motors Operated with Variable-Frequency Power Supply

A new speed control system for induction motors has been developed which is capable of controlling with quick field weakening and superior response and stability. This method is to control the stator current as a vector quantity on the basis of slip frequency control. More specifically, it is designed to calculate the commanded stator current of the induction motor by corresponding to flux and torque commands on the basis of motor constants and use the calculated commands to control the stator current.     

基于滑模变结构的永磁同步电机直接转矩控制

为解决传统永磁同步电机直接转矩控制中存在的电流、磁链和转矩脉动较大、逆变器开关频率不恒定、系统低速运行时难以精确控制以及因转矩脉动引起的高频噪声等问题,文中将滑模变结构控制策略引入永磁同步电机直接转矩控制中。用转矩和磁链2个滑模控制器来替代传统直接转矩控制中的2个滞环调节器,其输出实现空间电压矢量调制,保证了逆变器开关频率恒定。实验结果表明,这种新型控制策略能极大地减小传统直接转矩控制中存在的电流、磁链和转矩脉动,有效地抑制高频噪声,实现逆变器开关频率恒定,同时仍保持直接转矩控制固有的转矩快速响应的特征和对系统参数摄动、外干扰、测量误差以及测量噪声具有鲁棒性强的优点,有效地改善了系统的动、静态运行性能。     

实现感应电机宽范围最大转矩控制的电流优化策略

针对广泛应用于数控机床主轴驱动系统中的交流感应电机,提出了一种新的宽范围运行的电流优化控制策略。根据感应电机在不同速段的转矩特性,充分考虑逆变器的输出电压限制、电机本体的电流约束条件及最大转差频率限制,以输出最大转矩为目标,得出了全速范围内的最优电流控制轨迹和感应电机宽范围转矩输出最大化的电流优化分配指导原则。在此基础上,设计了一种工程实现算法,依据电机实际运行的状态变量实现恒转矩区、恒功率区与恒电压区的快速平滑过渡,完成了对最优电流控制轨迹的逼近。实验结果证明了提出方法的有效性,可以实现感应电机宽范围运行的最大转矩输出,并且使系统具有较快的动态响应性能。     

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.     

永磁同步电机有限集模型预测直接转矩控制

针对永磁同步电机(PMSM)模型预测直接转矩控制(DTC)转矩脉动大、功率元件开关频率不恒定等问题,将两电平逆变器的8个电压空间矢量作为有限控制集,应用到PMSM DTC中。设计考虑转矩误差、最大转矩电流比及电流约束的成本函数,利用成本函数来估算有限集合中各电压矢量的占空比,从而求得逆变器的最优电压矢量作为系统控制量。与传统模型预测控制方法相比,该方法的电流谐波和转矩脉动显著降低,且转矩动态性能也得到改善。仿真试验结果验证了所提出的控制方案有效性。     

电动汽车用异步电动机低速转矩最大化

电动汽车用异步电动机经常会遇到爬坡等低速重载运行工况,特别对于低压大电流的交流异步电动机,在逆变器电流限制条件下实现转矩最大化非常重要。以电机稳态电路为基础,建立电流约束条件下基于非线性励磁电感的低速转矩最大化模型。模型分析表明该最优问题可以简化为一维搜索问题,并采用经典的搜索算法在低速范围进行求解。实际电机计算结果和理论分析表明,整个低速范围内最大转矩值工作点的转矩值、齿部磁通密度、转差率几乎保持恒值,相当饱和的磁场导致严重的非线性。非线性励磁电感应用于改进的空间矢量控制系统,实现大电流约束条件下低速转矩最大化运行,仿真结果表明控制方法的正确性。实验结果也验证了转矩优化模型、模型分析结论及改进的空间矢量控制方法的正确性。     

Speed sensorless torque control of an IPMSM drive with online stator resistance estimation using reduced order EKF

Speed sensorless control of an interior permanent magnet synchronous motor (IPMSM) based on direct torque control (DTC) is proposed in this paper. The rotor speed and position of the IPMSM are estimated based on an active flux concept, where, the active flux vector position is identical to the rotor position. The proposed algorithm does not require neither high frequency injection signal nor complicated schemes even at vary low speed operation. Torque/ flux sliding mode controller (SMC) combined with space vector modulation is proposed to improve the performance of the classical DTC. Stator resistance value is required for a stator flux and electromagnetic torque estimation. Its variation due to temperature or frequency degrades the scheme performance, especially, at low speed operation. To overcome this problem, a reduced order extended Kalman filter (EKF) is proposed to update online the stator resistance. The advantages of the direct torque control, sliding mode controller, and speed sensorless control are incorporated in the proposed scheme. Simulation works are carried out to show the ability of the proposed scheme at different operating conditions. The results demonstrate the activity of the scheme at wide range speed operation with load disturbance and parameters variation.     

A new tension controller for continuous strip processing line

The strip tension as well as the line speed should be controlled tightly for the quality of products and productivity of the continuous strip processing line. In this paper, a new tension control algorithm with tension observer is proposed using observed tension as a regulator feedback. The tension observer as based on the torque balance of a roller stand, including the acceleration torque. Using this estimated tension, a new tension controller can be constructed with faster dynamic response in case of line speed acceleration or deceleration. The proposed scheme needs no additional hardware because the inputs of observer, current and speed, are already being monitored by the motor drive system. As this scheme directly controls torque current of the motor, better control performance can be obtained even without the tension transducer. Through the simulations and experiments with the laboratory setup, the performance of conventional schemes and the proposed one are compared. The results show the effectiveness of the proposed tension controller