感应电机定子电阻的模糊观测器及其应用

感应电机定子绕组温度的监测是电机安全运行的重要保障,基于电阴估计的温度监测方法为电机的过热代保护提供了一条新的途径,它的关键是准确估计实际的电阻值,本文基于模糊理论,设计了一种模糊电阻直接反映绕组的内部温度,适用于各种运行工误解,因此文中提出的定子温度监测方法可以作为电机过热保护的一种措施。     

Systematic experimental based modeling of a rotary piezoelectric ultrasonic motor

In this paper, a new method for equivalent circuit modeling of a traveling wave ultrasonic motor is presented. The free stator of the motor is modeled by an equivalent circuit containing complex circuit elements. A systematic approach for identifying the elements of the equivalent circuit is suggested. The Levenberg-Marquardt parameter estimation algorithm is used to model the alteration of the admittance after placing the rotor on the stator. Thereafter, theoretical assessments and experimental measurements are used to account for the speed reduction that is caused by placing the rotor on the stator and applying the load torque. Finally, the effects of temperature changes and the resultant response of the motor are computed. Results of the experiments and measurements are used to verify and validate the precision of the new modeling method.     

Online Detection of Broken Rotor Bar Fault in Induction Motors by Combining Estimation of Signal Parameters via Min-norm Algorithm and Least Square Method

Current research in broken rotor bar (BRB) fault detection in induction motors is primarily focused on a high-frequency resolution analysis of the stator current. Compared with a discrete Fourier transformation, the parametric spectrum estimation technique has a higher frequency accuracy and resolution. However, the existing detection methods based on parametric spectrum estimation cannot realize online detection, owing to the large computational cost. To improve the efficiency of BRB fault detection, a new detection method based on the min-norm algorithm and least square estimation is proposed in this paper. First, the stator current is filtered using a band-pass filter and divided into short overlapped data windows. The min-norm algorithm is then applied to determine the frequencies of the fundamental and fault characteristic components with each overlapped data window. Next, based on the frequency values obtained, a model of the fault current signal is constructed. Subsequently, a linear least squares problem solved through singular value decomposition is designed to estimate the amplitudes and phases of the related components. Finally, the proposed method is applied to a simulated current and an actual motor, the results of which indicate that, not only parametric spectrum estimation technique.     

基于旋转不变信号参数估计技术与模式搜索算法的异步电动机转子故障检测新方法

提出一种基于旋转不变信号参数估计技术(Estimation of signal parameters via rotational invariance technique,ESPRIT)与模式搜索算法(Pattern search algorithm,PSA)的异步电动机转子故障检测新方法。模拟形成转子故障情况下的定子电流信号并以之检验ESPRIT性能。结果表明:即使对于短时信号,ESPRIT仍具备高频率分辨力,可以准确估计定子电流各个分量的频率;但对其幅值、初相角的估计欠缺准确性、稳定性。随后,采用PSA确定各个频率分量的幅值、初相角。对一台异步电动机完成了转子故障检测试验,结果表明:基于ESPRIT与PSA的异步电动机转子故障检测方法是切实可行的,并且因仅需短时信号即可达到高频率分辨力而适用于负荷波动情况。     

Bacterial foraging algorithm application for induction motor field efficiency estimation under unbalanced voltages

In electric supply systems of industry and other entities, it is very common to find problems of power quality. Among these problems, unbalance and voltage deviation is one of the most common. They primarily affect the operation of electric motors. This paper proposes the use of a bacterial foraging algorithm as an economic, accurate and low-invasive tool, to obtain in field conditions, the output power, losses and efficiency of induction motors feed with unbalanced voltages. The algorithm is based on estimating the motor parameters of positive and negative equivalent circuits. The tool was tested on a 7.5 kW motor for different load conditions and high levels of voltage unbalance, yielding to accurate results, and demonstrating its effectiveness for performing energy audits in situ on unbalanced voltages conditions. This application of bacterial foraging technique has not been reported in the literature.     

Detection of broken rotor bars in induction motors using nonlinear Kalman filters

This paper presents a model-based fault detection approach for induction motors. A new filtering technique using Unscented Kalman Filter (UKF) and Extended Kalman Filter (EKF) is utilized as a state estimation tool for on-line detection of broken bars in induction motors based on rotor parameter value estimation from stator current and voltage processing. The hypothesis on which the detection is based is that the failure events are detected by jumps in the estimated parameter values of the model. Both UKF and EKF are used to estimate the value of rotor resistance. Upon breaking a bar the estimated rotor resistance is increased instantly, thus providing two values of resistance after and before bar breakage. In order to compare the estimation performance of the EKF and UKF, both observers are designed for the same motor model and run with the same covariance matrices under the same conditions. Computer simulations are carried out for a squirrel cage induction motor. The results show the superiority of UKF over EKF in nonlinear system (such as induction motors) as it provides better estimates for rotor fault detection.     

定子齿结构TRUM离散化动力学分析方法

基于目前行波型旋转超声电机定转子非线性接触动力学理论研究的复杂性,提出一种简易求解的界面离散化动力学分析方法。首先,着眼于定子齿的离散分布特性,化定转子齿面接触为离散点接触,在定子齿与转子的不同接触状态下,通过引入等效刚度的概念,对定子齿与转子间的轴向作用力进行求解,从而获得定转子的离散等效作用力,确立定转子的相对运动关系;然后,从离散接触点的三维运动特性出发,分析接触过程中的径向和周向摩擦力,从而研究输出机械特性和界面能耗;最后,通过仿真和实验,验证了该方法对接触界面动力学的准确描述。     

Application of Dempster–Shafer theory in fault diagnosis of induction motors using vibration and current signals

This paper presents an approach for the fault diagnosis in induction motors by using Dempster–Shafer theory. Features are extracted from motor stator current and vibration signals and with reducing data transfers. The technique makes it possible for on-line application. Neural network is trained and tested by the selected features of the measured data. The fusion of classification results from vibration and current classifiers increases the diagnostic accuracy. The efficiency of the proposed system is demonstrated by detecting motor electrical and mechanical faults originated from the induction motors. The results of the test confirm that the proposed system has potential for real-time applications.     

基于Park矢量的电动机轴承故障检测方法

提出了一种基于Park矢量的改进聚类处理算法,该方法通过辨识感应电动机三相定子电流中的故障信息来识别轴承故障。为了验证该方法的有效性,在电动机轴承上预设了故障,通过数字信号处理器采集数据,并利用上述方法进行处理。结果表明,所提出的方法可有效识别电动机的轴承故障。     

力平衡型多速双定子马达泄漏与容积效率分析

根据力平衡型多速双定子马达研究的基本原理,对其泄漏情况进行分析,研究了马达在2个和4个单马达同时工作时的容积效率变化,以及马达的3种主要泄漏:滑靴与定子表面、柱塞与转子柱塞孔以及配流壳筒与转子外表面的间隙泄漏,并进行了样机原理性实验。结果表明:随着进口油压的逐渐升高,泄漏量增大,马达容积效率呈下降趋势。该研究为力平衡型多速双定子马达的结构优化提供了参考。     

有限元法计算异步电机不同转速的等值电路参数

提出一种能够精确计算异步电机等值电路参数及其稳态性能的方法,该方法基于场路耦合的伪静止复数涡流有限元模型,铁芯饱和以及集肤效应直接在场中计及,不须考虑转子的转动,利用不同滑差时的磁场分析结果就能计算相应的等值电路参数,诸如端环,斜槽等三维效应可以通过传统的方法加以考虑。实验结果证明了该方法的有效性。     

基于横摆力矩的轮胎侧向力估计算法

通过对非线性汽车动力学模型进行分析,提出了一种基于横摆力矩的轮胎侧向力估计算法。轮胎侧向力的估计采用三个基本步骤,首先基于干扰观测器对侧向力横摆力矩进行估计,然后利用最小二乘法对两前轮与两后轮侧向力之和进行估计,最后采用垂向载荷按比例分配的经验方法对各轮胎侧向力进行估计。基于MATLAB/Simulink软件,对此轮胎侧向力估计系统进行仿真,将所得结果与CarSim动力学仿真软件结果进行对比,并采用硬件在环仿真平台进行试验验证。结果表明,所提估计算法能够准确地估计出轮胎侧向力,避免了复杂轮胎模型的运用以及对地面附着系数的依赖。     

感应电动机定子磁场定向直接转矩控制中定子电阻自适应估计方法

定子磁链定向的直接转矩控制技术逐渐被广泛应用于高性能异步电动机调速系统。而在低速运行阶段,由于定子电阻参数的变化,传统的磁场定向控制性能往往很差。基于此,利用波波夫超稳定理论提出了基于定子电流的参考模型自适应系统,通过定子电流反馈构成了对电动机参数进行闭环估计,不仅考虑了定子电阻与电动机转速变化参数,而且还考虑了电动机的转子电阻变化参数,进而加速了估计过程的收敛速度,提高了定子电阻及转速估计的精度。在此基础上,提出定子电阻整定的定子磁链估计方法,并建立一个定子磁场定向直接转矩控制的仿真系统。仿真结果进一步验证了其有效性。     

Fault diagnosis in six-phase induction motor using a current trajectory mass center

This paper proposes a new methodology for diagnosing the occurrence of stator winding faults in the six-phase induction motor. The proposed approach uses the xy current trajectory mass center of the motor stator currents. The Park transform is applied to the acquired induction motor stator currents. This transformation allows obtaining specific patterns that are used to identify stator winding faults. For healthy motors, a single point in the xy-plane is obtained. However, for a motor with a stator winding fault a circle is obtained, whose radius is related with the severity of the fault. To identify these patterns an algorithm, entitled current trajectory mass center, was developed. A theoretical analysis of the six-phase motor in αβ and xy current coordinates, for healthy and stator fault operation modes, is also presented. In order to show the applicability of the proposed technique several simulation and experimental results are presented.     

基于VB的永磁同步电机设计及优化平台

为解决传统永磁同步电机由于设计计算和查表工作复杂、耗时长、计算修正参数过多而导致精确性较差等的问题,将禁忌算法和模糊控制应用到传统永磁同步电机设计中,利用Visual Basic编写程序,对永磁电机磁路法设计过程进行了编程,建立了动定子结构尺寸和电机工作特性曲线之间的关系,提出了一种优化电机效率和功率因素,调整电机结构尺寸的方法;利用有限元软件对永磁同步电机的电感、功率等几个重要参数加以验证,并进行了瞬态仿真试验。仿真试验结果表明,该优化方法可提高电机的功率因素和效率,减小定子的电流密度,并可有效地优化永磁同步电机。     

低压散绕变频电机绝缘薄弱点定位方法研究

根据 IEC 相关标准,采用重复脉冲和正弦电压测定变频电机绝缘系统 PDIV,是评估低压散绕变频电机绝缘性能的关键 手段。 然而,现行 IEC 标准难以识别定子绕组绝缘薄弱点。 对此,联合重复脉冲和正弦 PDIV 离线测试技术,提出定位变频电 机绝缘薄弱点的“三步法”:首先采用重复脉冲电压测定电机匝间绝缘 PDIV;然后利用正弦电压测定相间及主绝缘 PDIV,并与 匝间 PDIV 对比,确定电机绝缘薄弱点;最后通过测试电机在不同接地方式下的 PDIV,可定位绝缘薄弱点是否位于定子绕组首 端。 另外,通过定子绕组电压分布仿真、3 个商用电机薄弱点识别及电机寿命实验,综合验证了上述方法的可行性。 此研究可 实现变频电机绝缘薄弱点的有效定位,提升电机绝缘潜在风险诊断效率。     

MRAS state estimator for speed sensorless ISFOC induction motor drives with Luenberger load torque estimation

This paper presents a novel method for estimating the load torque of a sensorless indirect stator flux oriented controlled (ISFOC) induction motor drive based on the model reference adaptive system (MRAS) scheme. As a matter of fact, this method is meant to inter-connect a speed estimator with the load torque observer. For this purpose, a MRAS has been applied to estimate the rotor speed with tuned load torque in order to obtain a high performance ISFOC induction motor drive. The reference and adjustable models, developed in the stationary stator reference frame, are used in the MRAS scheme in an attempt to estimate the speed of the measured terminal voltages and currents. The load torque is estimated by means of a Luenberger observer defined throughout the mechanical equation. Every observer state matrix depends on the mechanical characteristics of the machine taking into account the vicious friction coefficient and inertia moment. Accordingly, some simulation results are presented to validate the proposed method and to highlight the influence of the variation of the inertia moment and the friction coefficient on the speed and the estimated load torque. The experimental results, concerning to the sensorless speed with a load torque estimation, are elaborated in order to validate the effectiveness of the proposed method. The complete sensorless ISFOC with load torque estimation is successfully implemented in real time using a digital signal processor board DSpace DS1104 for a laboratory 3 kW induction motor.     

定子铁心混合叠压再制造电机的齿槽转矩分析

为提高再制造电机的性能,用非晶材料与硅钢材料混合叠压制成再制造电机定子铁心。基于能量法并结合定子混合叠压再制造电机的结构特征,提出以分段叠加算法近似替代三维计算定子混合叠压电机齿槽转矩的方法;基于近似叠加算法,利用分段设置反向斜槽的方法来减小齿槽转矩。应用Ansoft 3D软件分析了混合叠压方式对电机齿槽转矩的影响规律;对比分析了不同混合比例下电机的性能参数,确定了混合叠压的材料比例;对确定混合比例下正反斜槽后电机的齿槽转矩与空载电动势进行了分析。结果表明,定子混合叠压再制造电机的齿槽转矩与叠压方式无关,只与所用材料的比例有关;反向斜槽相比于正向斜槽,在有效减小齿槽转矩的同时,对电机性能的影响较小。将混合仿真与叠加计算结果进行对比,验证了二维叠加近似计算混合叠压的可行性。     

基于绕组函数的长定子直线同步电机建模研究

针对精确的直线同步电机数学模型建立困难的问题,提出了基于绕组函数法的长定子直线同步电机绕组电感的计算方法,并推导出了直线电机各电感参数计算公式,然后建立了相应的直线同步电机数学模型。此外,利用电感参数在Simulink里搭建了直线同步电机矩阵微分方程,通过仿真结果得到了三相电流、励磁电流和电磁推力波形。最后,基于长定子同步直线电机的结构尺寸建立了一对极有限元模型,定子绕组通入三相交流电,动子绕组通入直流励磁电流,通过设置适当的剖分,将得到的电磁推力和解析法的电磁推力进行了对比。研究结果表明,有限元分析法和解析法得到的电磁推力结果一致,从而论证了基于绕组函数法的直线电机数学模型建模方法,为以后的直线电机数学建模提供了参考。     

Highly precise determination of the state of charge of vehicular battery

An intelligent battery sensor is an important component for vehicular energy management, and the precision of online estimation of the state of charge determines sensor’s performance. A simple equivalent circuit was employed to describe the dynamic properties of vehicle lead-acid batteries. A model is reported to estimate the state of charge using the approximately linear relationship of open circuit voltage with this parameter. A time-varying circuit of the model was prepared and an identification model was derived to improve the accuracy. A method that employed a cascaded combination of double improved extended Kalman filters is reported and employed in a demonstration intelligent battery sensor. This approach has higher precision and speed in estimating the state of charge compared to previous protocols.