基于滤波算法的感应电动机参数离线辨识

感应电机的参数辨识是电机控制领域的一个重要课题,获取高质量的电机参数是构建控制系统数学模型、实现电机最优控制的重要前提。在对感应电机的等效电路进行再分析后,抓住感应电机自身电流滞后的特点,在传统电机参数辨识方法的基础上,分别进行了改进的单相交流实验、直流实验和三相交流实验,通过滤波计算,依次获取电机定子电阻、定子电感、定转子互感和转子电阻,并通过Matlab仿真和实验,验证了该离线辨识技术的准确性。     

定转子电阻在线辨识的感应电机转速估计方法

针对感应电机参数变化导致转速估计不准的问题,提出了一种基于定、转子电阻在线辨识的模型参考自适应转速估计方法.该方法只需检测定子侧的电压和电流,在估计电机转速的同时,在线辨识定转子电阻,实时更新转速估计系统中受电机温升影响而变化的定子电阻和转子电阻,以保证转速估计的精确度;同时,辨识的转子电阻应用于矢量控制系统,确保系统获得良好的稳态和动态性能.仿真及实验结果表明,与未进行电阻在线辨识的转速估计方法相比,该方法具有较高的转速估计精确度,对参数变化的鲁棒性强,并适用于无速度传感器矢量控制系统.     

基于自适应观测器的感应电机转速估计方法研究

介绍了一种能在线补偿定转子电阻的基于自适应观测器的感应电机转速估计方法.该转速估计方法只需检测定子电压电流作为输入,利用观测器观测出转子磁链和定子电流,并利用定子电流误差和转子磁链观测值辨识出转速、定子电阻和转子电阻,并反馈于观测器,确保电机转速估计对参数变化的鲁棒性.仿真及实验结果表明,此方法估计的速度能应用于无速度传感器矢量控制系统,并具有较好的辨识精度和鲁棒性.     

磁通观测改进的无速度传感器DTC系统

针对定子电阻摄动与积分漂移对直接转矩控制(DTC)性能的影响,在分析直接转矩控制特点的基础上,推导了以电机有功功率为基础的定子电阻辨识算法与以反电动势为基础的定子磁链辨识算法,并将坐标系定向于定子电流矢量上推导出转速估计算法.以此建立的直接转矩控制系统,定子电阻辨识算法不依赖电机其他易变参数,转速估计中未使用转子电阻或转子时间常数;通过4kW感应电机无速度传感器DTC系统仿真试验表明,积分漂移得到有效抑制,估计速度与实际速度良好吻合,系统具有较好调速性能.     

基于扩展卡尔曼滤波器的异步电机矢量控制系统的转子电阻辨识

异步电机的转子电阻是电机控制系统中变化最为明显的参数之一,因此准确、快速地辨识转子电阻是提高矢量控制系统鲁棒性的研究重点.提出一种基于扩展卡尔曼滤波(EKF)实现异步电机转子电阻估计的方法,该方法采用异步电机的双闭环矢量控制策略,通过测量电机定子电压、电流及电机转速,在线辨识电机转子电阻.在MATLAB/Simulink中建立系统仿真模型,并分析了转子电阻变化对转速的影响,结果验证了该算法的有效性和准确性     

一种交互式模型参数自适应感应电动机参数在线辨识方法研究

在基于转子磁链模型参考自适应理论的基础上,给出了一种参考模型和可调模型交互式的模型参数自适应(MRAS)方法,使系统能在电机转速和定子电阻辨识之间相互切换.该方法消除了纯积分和电机漏感对算法的影响,电机的低速性能得到了改善;同时,对定子电阻进行在线辨识,从而得到准确的转速观测结果,也能近似地辨识转子电阻.计算机仿真结果证明了该方法的有效性.     

嵌入式永磁同步电机离线参数辨识技术

详细介绍了一种永磁同步电机(Permanent Magnet Synchronous Motor,简称PMSM)矢量控制系统电机参数的离线辨识技术.该技术基丁电机的动态数学模型,通过在电机端注入直流或交流电流,测量相应的电压响应,辨识出电机的定子电阻、转子磁链、直轴电感和交轴电感.实验结果证明了该算法的正确性.     

基于自适应线性元件神经网络的表面式永磁同步电机参数在线辨识

提出一种基于自适应线性元件(Adaline)神经网络辨识表面式永磁同步电机定子绕组电阻、电感和转子磁链的方法。所提出的辨识方法不需要知道电机的任何设计参数信息,只需在线采样定子电流、电压和转速值即可。该方法首先在电机静止状态时估算出定子绕组电阻值,并利用该电阻值在电机启动时辨识出转子磁链和定子电感值,而所辨识出来的转子磁链值将被进一步用来在线估算定子绕组电阻的变化。实验显示该方法能够有效辨识定子电阻、电感和转子磁链。此外,当电机带负载运行时,该方法依然能够有效地在线跟踪电机定子绕组电阻变化。     

矢量控制预起动状态下电机参数的辨识

研究了矢量控制异步电机静止时的参数离线辨识方法。该方法采用直流实验辨识电机的定子电阻,采用逆Γ等效电路模型进行转子电阻、定转子漏感以及互感辨识,通过两次不同频率的单相实验辨识电机的等效转子电阻、总漏感以及等效互感,再由一次单相实验的电抗值,采用迭代法提高等效互感的精度,根据逆Γ等效电路参数解出异步电机的转子电阻、定转子漏感及互感。使用该方法可以在静止状态下准确辨识出异步电机矢量控制所需要的电机初始参数,而且辨识原理相对简单、辨识精度高,能够满足高性能矢量控制系统的要求。实验结果证明了该方法准确、有效。     

基于扩展卡尔曼滤波器的异步电机矢量控制系统的转子电阻辨识

异步电机的转子电阻是电机控制系统中变化最为明显的参数之一,因此准确、快速地辨识转子电阻是提高矢量控制系统鲁棒性的研究重点。提出一种基于扩展卡尔曼滤波（EKF）实现异步电机转子电阻估计的方法,该方法采用异步电机的双闭环矢量控制策略,通过测量电机定子电压、电流及电机转速,在线辨识电机转子电阻。在MATLAB/Simulink中建立系统仿真模型,并分析了转子电阻变化对转速的影响,结果验证了该算法的有效性和准确性。     

Nonlinear adaptive state-feedback speed control of a voltage-fed induction motor with varying parameters

An adaptive nonlinear-state-feedback speed control scheme of a voltage-fed induction motor has been developed in which the control of torque and flux is decoupled. The inputs to the control algorithm are the reference speed, the reference flux, the measured stator currents, the measured rotor speed, the estimated rotor flux, and estimates of the rotor resistance, stator resistance, and load torque, which may vary during operation. The controller outputs are the reference stator voltages in rotor-flux rotating reference frame. An accurate knowledge of the rotor flux and machine parameters is the key factor in obtaining a high-performance and high-efficiency induction-motor drive. The rotor flux is estimated using the induction-motor rotor-circuit model. Although the estimated rotor flux is insensitive to the stator-resistance variation, it does depend on the rotor resistance. A stable model reference adaptive system (MRAS) rotor-resistance estimator insensitive to stator-resistance variation has been designed. Stable stator-resistance and load-torque MRAS estimators have also been developed. These estimators have been developed to constitute a multi-input-multi-output (MIMO) decoupled-cascade structure control system. This simplifies the design problem of the estimators for a stable operation from a MIMO design problem to a single-input-single-output (SISO) design problem. The continuous adaptive update of the machine parameters and load torque ensures accurate flux estimation and high-performance operation. Simulation and experimental results are presented to verify the stability of the induction-motor drive in various operating modes.     

Rotor temperature estimation of squirrel-cage induction motors by means of a combined scheme of parameter estimation and a thermal equivalent model

This paper deals with a rotor temperature estimation scheme for fan-cooled mains-fed squirrel-cage induction motors. The proposed technique combines a rotor resistance estimation method with a thermal equivalent circuit. Usually, rotor resistance estimation works quite well under rated load conditions. By contrast, if the motor is slightly loaded, rotor resistance estimation becomes inaccurate due to the small slip. Therefore, rotor temperature estimation under low-load conditions may be estimated by a thermal equivalent model. In order to determine the rotor resistance and, thus, rotor temperature accurately, several machine parameters have to be obtained in advance. Load tests provide the leakage reactance and the iron losses of the induct machine. The stator resistance has to be measured separately. The parameters of the thermal equivalent model are a thermal resistance and a thermal capacitance. These parameters are derived from a heating test, where the reference temperature is provided from the parameter model in the time domain. This lumped thermal parameter model is based on the assumption that the total rotor temperature increase is caused by the total sum of the losses in the induction machine. Measuring results of a 1.5-kW and an 18.5-kW four-pole low-voltage motor and a 210-kW four-pole high-voltage motor are presented and compared.     

A control strategy for stand-alone wound rotor induction machine

A control strategy to regulate the frequency and voltage of a stand-alone wound rotor induction machine is presented. This strategy allows the machine to work as a generator in stand-alone systems (without grid connection) with variable rotor speed. A stator flux-oriented control is proposed using the rotor voltages as actuation variables. Two cascade control loops are used to regulate the stator flux and the rotor currents. A closed loop observer is designed to estimate the machine flux which is necessary to implement these control loops. The proposed control strategy is validated through simulations with satisfactory results.     

A simplified approach to continuous on-line tuning offield-oriented induction machine drives

A simplified approach to the continuous online tuning of rotor flux feedforward field-oriented induction machine drives is presented. The procedure offers the advantage of not requiring a special test signal or special test conditions. The approach takes advantage of the stator voltage equations which allow robust parameter-insensitive estimation of the electromagnetic torque while operating at nominal speeds for which the stator IR voltage drop is negligible (≈5 Hz and above). This torque computation is independent of the rotor flux field-oriented control. In essence, the approach uses a stator flux controller to detect improper tuning of the feedforward rotor flux controller. The theoretical and practical implementations of such a continuous self-tuning system are presented. Experimental results are based on a rotor flux feedforward field-oriented induction machine servo drive     

Consideration about problems and solutions of speed estimation method and parameter tuning for speed-sensorless vector control of induction motor drives

A classical model-based speed-sensorless field-oriented control method for a general-purpose induction machine is considered. Improved versions of both speed and stator resistance online estimators are presented with the aim of extending control capabilities down to zero speed. Only electrical stator measurements are needed, making the method suitable for general-purpose inverter applications. Online rotor resistance tuning is also included to fully compensate for thermal drift. Performance of the proposed drive is investigated by simulation and experiments.     

无刷双馈电机谐波铜耗与铁耗的分析与计算

针对无刷双馈电机谐波含量高、谐波损耗大的问题,提出考虑谐波磁场、谐波电流、集肤效应和旋转磁化影响的BDFM损耗计算模型.基于二维场路耦合时步有限元模型和谐波分析方法,分别建立两种转子铜耗计算模型和三种定转子铁耗计算模型,分析不同计算模型对转子铜耗和定转子铁耗的影响,得到定转子谐波铜耗和铁耗的变化规律.结果表明,转子铜耗模型2以及定转子铁耗模型3更精确;随着控制绕组电压的增加,定转子铜耗先减小后增加,定转子铁耗持续增加;随着负载转矩的增加,定转子铜耗和铁耗均随之增加.通过与一台相似异步电机铜耗和铁耗的电磁设计数据和实验数据的比较,验证了模型与计算结果的正确性.     

A brushless electric motor with a transverse magnetic flux and disk rotor

Brushless permanent magnet machines (BPMMs) have a greater efficiency and smaller overall dimensions than do other types of machines and are widely used in electric drives for various purposes. Two types of BPMMs are used in practice: BPMMs with a classical double-layer-distributed stator winding and BPMMs with a toothed-step stator winding. There exists another type of BPMM with a transverse magnetic flux (transverse flux motors, TFMs) which is being actively studied. In TFM electric motors, the magnetic lines of fluxes of the poles of rotor end perpendicular to the direction of rotor rotation. Stator windings in these machines are fabricated as rings coaxial with rotor, and the magnetic circuit of stator consists of separate fragments. Specialists assert electric TFMs have a higher specific power—the ratio between the output power and the mass of the machine—than the electric motors of other type. They are of interest, first and foremost, for electric drives without reducing gears. In most TFM, only a half of the poles of rotor are magnetically connected with circular phases of stator. In this work, the TFM design with disk rotor is described, in which the magnetic flux of all poles of rotor is coupled to the circular phases of stator. The stator magnetic circuit in this machine consists of P-like elements, and alternation of polarity of these elements is provided due to the change of their position. As a result, the magnetic flux coupled to the circular phase increases doubles, as do the machine torque and power. Some results of modeling of a three-phase electric motor are presented. The results were obtained using the Ansys Maxwell computer code, including a graph of the change of torque on the shaft of a machine under rotation of the rotor under conditions of sinusoidal currents in phases.     

A novel technique of rotor resistance estimation consideringvariation of mutual inductance

The study proposes a method to estimate AC induction-machine mutual inductance and rotor resistance based on terminal voltage, current, and shaft speed as input signals. For certain operating regions of the machine, it is verified that the mutual inductance can be accurately estimated regardless of wide stator resistance variation. The equations to estimate mutual inductance and rotor resistance are derived from the machine's nonlinear differential equations. The nonlinear equations are solved using integration. The initial condition for each integration is found by an averaging of measured input signals. The validity of the suggested method is confirmed by computer simulation and experimental tests. The simulation results considered the dynamics of the induction machine, current controller, and field-oriented controller and show that the mutual inductance and rotor resistance can be estimated with reasonable accuracy even in the transient state. Mutual inductance and rotor resistance estimations for the experimental test results support the simulation results with negligible error     

A FULLY DIGITAL SENSORLESS DIRECT TORQUE CONTROL SYSTEM FOR SYNCHRONOUS MACHINE

ABSTRACT

A new sensorless controller based on direct torque control, for a synchronous machine is proposed. Using direct torque control, stator resistance is the only parameter of the machine which should be known. The use of reactive torque control simplifies the field current control loop. Initial stator induced currents are used to estimate the initial stator flux. The outputs of the control system are switching commands of stator inverter and rotor chopper.     

定子电阻对无速度传感器系统的影响及其在线调整

分析了定子电阻对无速度传感器系统的影响,指出定子电阻变化引起的定子磁链稳态误差与电阻误差值、电流幅值、同步角速度和初始误差值有关,最终影响磁场定向和转速估算的准确性.基于定子磁链处于稳态时,转子电流矢量应与转子磁链矢量垂直的原则,提出了一种闭环形式的定子电阻在线调整方法.该方法使用比例(P)调节器以控制目标量为零,调整定子电阻值.仿真结果表明在转速给定10 r/min,定子电阻线性增加和减小50%的情况下,转速波动不超过10%,定子磁链幅值偏差在0.02～0.05 Wb之间,定子磁链的相位偏差不超过0.2 rad.