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。     

一种新型的电机参数离线辨识系统

在实际工程应用中,常规空载实验和堵转实验辨识电机参数的方法难以实现,且辨识精度不高,针对此问题,设计了一种基于TMS320F2808的异步电机参数辨识系统.该系统能够通过直流实验、单相交流实验以及空载实验代替常规辨识方案对工程现场电机的参数进行辨识.这里论述了异步电机参数辨识系统的设计和实现过程,并对电机参数辨识中出现...     

一种简易的异步电机参数辨识方法及其应用

介绍一种简易的异步电机参数辨识方法,该方法能在电机静止状态下辨识出电机的各个参数,并在基于TMS320F2812为主控制器的异步电机无速度传感器矢量控制系统进行实验,将辨识得到的参数投入到实际系统中,通过LabVIEW虚拟示波器观测系统的实际运行情况。实验结果证明该方法辨识得到的参数准确性高,能直接应用于无速度矢量控制系统,而避免了繁琐的参数整定过程。     

间接矢量控制系统中的异步电动机参数辨识

本文详细介绍了间接矢量控制系统中的异步电动机参数辨识方法.通过改进的直流试验和单相交流试验辨识出异步电动机的定子电阻、转子电阻和定转子漏感;采用转差频率控制,实现电机的空载试验,从而辨识出互感.以上三个试验可以辨识出间接矢量控制所需要的全部参数,并且精度更高,算法更简单,最后以带载试验来证明辨识的参数是准确的.本文提出的方法充分利用了全数字间接矢量控制的有利条件,简化了算法,实现了电机参数的准确辨识,从而保证了这类系统的控制性能.     

异步电机离线参数辨识方法

为了能让变频器与电机快速实现匹配,并达到较好的控制效果,往往需要对电机参数进行参数辨识.现就异步电机离线参数辨识进行分析,辨识的主要参数有:定子电阻、定子漏感、转子电阻、转子漏感、互感以及空载电流.并通过工程实现,对电机参数辨识精度进行确认及误差分析.     

基于新型卡尔曼滤波器的无轴承异步电机无速度传感器控制

为了提高无轴承异步电机无速度传感器矢量控制系统的精度,提出一种新型串联卡尔曼滤波器,通过将容易变化的电机参数作为待辨识状态向量增广到系统模型中,实现电机参数的在线计算,并将得到的参数值反馈到算法中实现电机转速的准确辨识,从而减小电机参数变化对转速估算精度的影响。通过采取三个扩展卡尔曼滤波器的串联结构降低系统模型矩阵的阶数,减小实际应用中数字芯片的计算负荷。通过仿真和实验对比了在电机参数变化时传统扩展卡尔曼滤波器和新型串联卡尔曼滤波器的估计转速误差,结果表明新型卡尔曼滤波器能有效减小参数变化对估计精度的影响,确保转子稳定悬浮运行。     

永磁同步电机非线性电感参数离线测量

永磁同步电机(PMSM)参数的准确获取有助于电机的高效控制。此处设计了一种新的PMSM非线性电感参数的离线测量方法,可以辨识出不同电流、不同转子位置下的PMSM三相自感以及互感。此方法通过引出电机中线实现三相解耦,从而分别控制三相电流,对各相分别进行电压注入,得到各相的电压以及电流响应,通过傅里叶分析提取基波幅值计算电机电感参数。此处针对一款内置式PMSM进行实验,结果表明,该方法能较准确地测量多种工况下的电机非线性电感参数。     

异步电机电感参数的离线辨识

在异步电动机反Γ型等效电路的基础上,提出了一种定转子总漏感与互感的离线辨识方法。在已有的异步电机运动控制平台上进行含高频成分很重的单相脉冲和单相低频正弦实验,然后根据霍耳传感器检测到的电压电流信号,经傅立叶变换来实现对异步电机参数的辨识,实验表明辨识结果具有较高的精度。并对逆变器的死区效应进行了一定的补偿,使计算得出的电压与逆变器实际输出电压基本一致,电流波形接近正弦波,补偿效果能满足参数辨识精度的要求。     

异步电机参数离线辨识改进算法

为实现变频调速系统的自运行(self-commissioning),提出了一种异步电机参数离线辨识的改进算法,该算法能直接辨识出与无速度传感器定子磁场定向矢量控制相关的大部分电机参数。利用直流实验辨识定子电阻,并通过分析逆变器的开关状态,得到直流实验的等效控制电路。采用单相交流堵转实验辨识定子总漏感和转子电阻,并通过分析异步电机相量图得到单相交流堵转实验稳定运行的工作条件。恒压频比空载实验辨识定子自感,对电机定子频率进行补偿以消除可能出现的定子电流振荡。利用直流侧电压和PWM占空比来重构定子电压,并根据电机电流极性补偿逆变器死区引起的电压误差。最后,在两台不同功率等级的异步电机上进行了参数辨识和无速度传感器定子磁场定向控制的实验研究。实验结果表明,参数辨识结果对直流侧电压不敏感,辨识得到的电机参数能满足无速度传感器矢量控制系统对电机参数准确性的要求。     

基于数字信号处理器的异步电机参数辨识实现

介绍了异步电机各种参数的辨识方法。在不改变硬件系统的前提下,通过电流控制技术,向电机注入单相交流或直流电流,检测其响应,从而实现异步电机的参数辨识。对一台未知参数的异步电机做仿真和试验研究,并将辨识出来的参数用于矢量控制系统,得到了良好的效果,证明了参数辨识的正确性。     

考虑互感影响的开关磁阻电机无位置传感器控制技术

针对开关磁阻电机采用电流斩波控制(CCC)方式时相间互感对无位置传感器角度估算的影响,提出一种转子位置估算方法,该方法可以消除相间互感对位置估计的影响,并且无需测量相间互感大小。当电机在单相励磁区时,此时采用变系数电感模型方法进行角度估计;当电机在两相同时处于励磁区时,相间互感不为零,此时对导通相的磁链做差值运算以消除相间互感,最终通过实验对提出的转子位置估算方案进行验证。实验结果表明,与传统的忽略相间互感影响的转子位置估计方案相比,该方案能够消除互感对转子位置估计的影响,并且具有更高的估计精度,能够实现较大转速范围的无位置传感器稳定可靠运行。     

基于多项式磁饱和模型及EKF的感应电机磁链观测

感应电机的转子磁链通常用定子电流进行观测,易受测量噪声影响,且观测模型精度与电机参数有关。当电机内磁场幅值变化时,磁路非线性饱和效应会引起互感参数波动,导致观测磁链的幅值和方向偏离实际值,使控制出现偏差。对此,提出基于四阶多项式磁饱和模型以及扩展卡尔曼滤波(EKF)的全状态估计算法,以定子电流作为反馈,观测转子磁链的同时,辨识互感参数。仿真及实验结果表明所提算法能降低磁饱和非线性对控制系统的影响。     

Nonlinear systems time-varying parameter estimation: Application to induction motors

In this paper, an algorithm for time-varying parameter estimation for a large class of nonlinear systems is presented. The proof of the convergence of the estimates to their true values is achieved using Lyapunov theories and does not require that the classical persistent excitation condition be satisfied by the input signal. Since the induction motor (IM) is widely used in several industrial sectors, the algorithm developed is potentially useful for adjusting the controller parameters of variable speed drives. The method proposed is simple and easily implementable in real-time. The application of this approach to on-line estimation of the rotor resistance of IM shows a rapidly converging estimate in spite of measurement noise, discretization effects, parameter uncertainties (e.g. inaccuracies on motor inductance values) and modeling inaccuracies. The robustness analysis for this IM application also revealed that the proposed scheme is insensitive to the stator resistance variations within a wide range. The merits of the proposed algorithm in the case of on-line time-varying rotor resistance estimation are demonstrated via experimental results in various operating conditions of the induction motor. The experimental results obtained demonstrate that the application of the proposed algorithm to update on-line the parameters of an adaptive controller (e.g. IM and synchronous machines adaptive control) can improve the efficiency of the industrial process. The other interesting features of the proposed method include fault detection/estimation and adaptive control of IM and synchronous machines.     

Induction Motor Rotor Temperature Estimation Based on a High-Frequency Model of a Rotor Bar

This paper analyzes a high-frequency (HF) voltage-injection-based rotor winding temperature estimation method for current-regulated squirrel-cage induction motors (IMs). We develop a theoretical HF model of the rotor bar and then first provide an analysis of relevant HF model-based estimation aspects, such as the dependence of the rotor leakage inductance on the temperature and the relationship between the rotor resistance and rotor leakage inductance. We also include an analysis of magnetic saturation to improve the estimation accuracy, as well as an analysis of the phase delay effect resulting from the drive that significantly affects the HF signal precision. Then, a specialized offline commissioning scheme is proposed to compensate for the effect of the phase delay and magnetic saturation. The estimation technique and sensitivity analysis are verified by means of experiments performed on an inverter-fed 1.5-kW IM.     

基于TensorFlow神经网络的MCR-WPT系统负载与互感识别方法

针对磁耦合谐振式无线电能传输(MCR-WPT)系统负载与互感识别精度低、速度慢等问题,提出一种基于TensorFlow神经网络的双LCC型MCR-WPT系统负载与互感识别方法.该方法基于TensorFlow深度学习框架,采用神经网络模型,将MCR-WPT系统的负载与互感识别问题等效为非线性方程的求解问题,进而转化为深度学习非线性拟合问题,并给出模型的训练方法,最后得到基于TensorFlow神经网络的MCR-WPT系统负载与互感识别模型.通过离线方式训练负载与互感识别模型,并将训练完成的识别模型导入微型控制器,只需要采集系统输入电流值和传输距离就能够实现负载与互感在线同时识别,识别速度快、精度高,有利于系统的实时控制,且成本较低、易于实现,有利于工程推广应用.     

电缆故障脉冲电流测距系统建模与仿真

为解决电缆故障脉冲电流测距系统的精确仿真问题,提出了一种用于脉冲电流测距系统的建模与仿真方法.建立了RLC串联的高压信号发生器模型和考虑线圈互感、自感、自阻及其集肤效应的线性电流耦合器模型,并对模型中的参数进行了准确量化.针对线性耦合器传递函数不收敛问题,利用修正后的传递函数计算其二次电压信号.实际脉冲电流测距系统的仿...     

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     

基于非线性拟合单位电流最优输出功率的永磁同步电机位置估计误差补偿策略

针对永磁同步电机(permanent magnet synchronous motor, PMSM)参数变化影响转子位置估计精度问题,提出了一种基于单位电流最优功率输出的位置估计误差非线性补偿策略。首先,分析了电机参数误差特别是电感误差对位置估计精度的影响,建立了位置估计误差与单位电流输出功率的关联模型,推导出电感误差与最优输出功率的关系模型。然后,结合功率模型构建了基于多项式的电感误差非线性模型,利用少量测试点拟合该多项式模型,即可辨识电感误差用于准确补偿位置估计误差。所提方法实现简单,不依赖电机参数,能有效克服噪声干扰。最后,仿真与实验结果验证了提出补偿策略的有效性。     

Compensation for parameter variation of induction motor improved torque control characteristics in low- and high-speed regions

In the vector control system using the slip frequency control method, the rotor resistance of an induction motor is used to calculate a slip frequency. Thus the change in temperature of the rotor resistance causes the deterioration of the torque control characteristic. This paper presents a new method of compensating for the rotor resistance change which is robust for the stator resistance change. A current control loop is composed of the λ-δ axes in which the λ axis is coincident to the stator current. In this method, the stator voltage error on the δ axis which is directly obtainable from this current control loop was used. The change in the stator voltage was able to be detected accurately, therefore the torque control accuracy was improved, particularly in the low-speed region. The experimental results of the current response and the compensation for the rotor resistance deviation also are shown. Moreover, although the mutual inductance has been treated as an invariable value, the value does change by a frequency and an exciting command. In this control method, an initial tuning of the equivalent mutual inductance was achieved by detecting the deviation component of the stator voltage on the δ axis at the no-load running condition. Furthermore, in the region with the constant power where the field weakening control was achieved, the excellent experimental results of the compensation for the deviation of the equivalent mutual inductance are shown.