基于PWM逆变器的直线感应电机参数辨识方法

针对直线感应电机初级漏感和次级漏感不相等的特性,提出了一种基于PWM逆变器的直线感应电机参数辨识方法,将堵转试验的等效电路改进后得到方程组计算电机的参数。将此方法应用于一额定电压30V的直线感应电机参数辨识中,试验结果与传统方法得到的试验结果比较,证明了所提出的方法提高了辨识精度。     

直线感应电机离线参数辨识及关键辨识参量研究

针对直线感应电机初级漏感和次级漏感不相等的特性,提出一种基于PWM逆变器的直线感应电机离线参数辨识方法。首先,在电机静止的条件下,先向电机中通入单相直流电压来获得初级电阻,再依次通入单相高频交流电压和单相低频交流电压来依次获得互感、次级漏感、初级漏感和次级电阻。其次,讨论了电机参数的辨识误差与频率变化的关系,给出了使用该方法时高频实验和低频实验中适用的频率范围,并建立了直线感应电机离线参数辨识模型来进行仿真实验。最后,针对不同功率的直线电机,将该方法辨识结果与传统的空载和堵转实验方法的辨识结果进行对比。结果表明,提出的辨识方法由于考虑了直线电机初、次级漏感不相等的特性,其辨识精确度更高。     

高速短初级直线感应电动机等效电路模型及时变参数辨识

由于受到动态纵向边端效应和铁心饱和的影响,直线感应电机传统等效电路模型电磁参数时变.针对此,本文提出了多因素耦合影响下高速短初级直线感应电机等效电路模型及其时变参数辨识方法.首先,分析不同工况下电机推力变化规律;其次,分析电机电磁参数与运行工况之间的规律,提出激磁电感和次级电阻修正系数,构建直线感应电机改进等效电路模型,并通过响应面分析法计算两个修正系数;最后,开展样机静态堵驻实验和动态实验.计算和实测结果表明:推力计算值与实测值误差不超过4.1％,端口基波正序阻抗的实部、虚部计算值与实测值误差不超过4.7％,验证了时变参数辨识的准确性.     

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.     

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。     

一种新型的直线异步电机参数测量方案

单边直线异步电机(SLIM)的T型电路参数是电机控制的基础,它在无速度传感器控制和在线参数辨识中更为重要.SLIM相对旋转异步电机(RIM)存在气隙大、边缘效应等,若采用RIM开路和短路试验方法,会给参数测量带来较大误差.本文提出一种适合SLIM参数测定的新型方案,只需测量电机输入端的总功率、相电压、相电流和频率4个量,计算出初级电阻、初级漏感、次级电阻、次级漏感、气隙电感和铁损电阻.电机的特性分析表明,该方法真实有效,具有一定的参考价值.     

一种消除非线性因素的电机参数辨识方法

针对电压型逆变器因电机参数不准确而导致控制性能下降的问题,该文提出了一种离线辨识电机参数的方法。该文结合异步电机静止下的数学模型,采用静止测量和旋转测量方法来辨识电机参数,并考虑死区效应、涡流效应、集肤效应等因素,消除了测量过程中的非线性因素影响。其中静止测量可以较为准确的测出电机定子电阻、转子电阻、漏感、励磁电感和额定励磁电流;旋转测量校正了励磁电感和额定励磁电流。相关算法在7.5 k W和160 k W感应电机变频调速系统上进行了实验验证,结果证明该方法能较为准确的得到电机相关参数。     

栅格次级双边直线感应电机特性

分析了长初级双边型直线感应电机(DSLIM)无铁心栅格次级中感应涡流稳态特性,推导出直线感应电机栅格次级电阻、漏感计算公式,提出一种考虑次级端部导条电阻和纵向边端效应的栅格次级DSLIM等效电路,利用场路联合方法简化了栅格次级DSLIM有限元分析模型。计算并测试对比了栅格次级和平板次级在同一初级下的堵转特性,验证了等效电路和场路联合两种计算方法的正确性。结果表明,栅格次级能消除直线感应电机的第二类横向边端效应、规范气隙横向磁场、提高电机力功比。     

直线感应电机在线参数辨识

直线感应电机存在动态边端效应,励磁电感等参数随电机运行速度变化,离线参数辨识方法无法准确掌握电机参数,导致控制电机动态性能变差。本文采用模型参考自适应系统进行直线感应在线参数辨识,推导了直线感应电机状态空间方程,提出一种直线感应电机励磁电感在线辨识的算法。本文建立的电机状态观测器能够准确计算初级电流与次级磁链,参数辨识算法收敛性较好,实验和仿真结果表明电机励磁电感参数计算准确,能够正确反映动态边端效应对电机励磁参数影响的物理特性,即电机励磁电感随速度增加而减小。     

一种新型的交互式MRAS速度辨识仿真

提出一种新型的交互式MRAS.在基于无功功率的MRAS基础上,将参考模型和可调模型互换,同时辨识感应电机转速和定子漏感.该方法引入无功功率物理量,使参考模型中不包含纯积分和定子电阻,并且通过辨识并在线调整定子漏感,消除了定子漏感变化对MRAS速度辨识精度的影响.仿真结果表明,该方法提高了系统对参数变化的鲁棒性,拓宽了调速范围,且具有结构简单的特点.     

Optimized Energy‐Saving Speed Profile in Linear‐Motor Railway System

The most striking characteristic of linear‐motor railway system is that the structure consists of a primary and secondary linear induction motor (LIM). The primary side of the LIM is installed in a rolling stock, and the secondary side of LIM is installed on the track. The magnetic attractive vertical force produced by the LIM increases the running resistance since this force is in the same direction as the gravitational force due to which rolling stocks gain weight virtually from the track side of view. In addition, the efficiency of the LIM has different characteristics of efficiency compared with the rotary motor. Previous studies have focused on the design method of LIM to improve motor efficiency and decrease energy consumption. However, it is a well‐known fact that this kind of approach requires hardware renewal which requests large amount of investments. The purpose of this study is to analyze these characteristics of LIM effects and design the optimal speed profile to minimize the energy consumption as a linear‐motor railway system. This smart and economic energy‐saving approach is based on the optimization of speed profiles of the linear‐motor railway system using dynamic programming.     

一种考虑边端效应的直线感应电机改进解耦控制策略

直线感应电机独特性引起的参数变化会带来电流控制时的解耦困难,因为传统前馈解耦控制器在电机参数有误差时表现不佳。本文在考虑边端效应的直线感应电机的矢量控制策略中,采用了一种改进的解耦控制器作为电流控制器,提高了系统对抗参数变化的鲁棒性,同时易于实现。这种方法的有效性通过Matlab/Simulink中的仿真进行了验证。     

Edge effect and independently supplied slot currents in tubular linear induction motors

The linear induction motor (LIM) is divided structurally into the flat and the tubular-type. This paper examines one kind of tubular linear induction motor whose primary configuration consists of four pieces of a flat-type core. We call this type of motor “the square tubular LIM.” The square tubular LIM has various merits of the cylindrical tubular LIM in addition to those of the usual flat-type LIM. The two remarkable features of the square tubular LIM that the flat-type LIM does not have are as follows. The first feature is that it has no edge effect, and the second is that the normal force in secondary conductor is cancelled by that of the opposite side of the secondary conductor. In comparison with the cylindrical tubular LIM, moreover, the square tubular LIM is easy to manufacture and maintain. The tubular LIM also has a feature that its primary winding is a kind of ring winding. Thus we can supply independently the primary current in each slot and hence easily obtain various winding schemes. Finally, the features of the square tubular LIM are studied. After numerically analyzing an experimental model, the motor is driven by the independently controlled slot currents, resulting in the expected performance.     

直线感应电机的有限元仿真与分析

分析了用于城市轨道交通的直线感应电机的结构特征及其等效电路,阐述了相关参数的计算方法,包括电机励磁电抗、效率、功率因素等,并应用Ansoft有限元软件,对一台直线感应电机样机进行了电磁分析。通过有限元仿真与分析,得出了电机内部电磁场的分布特点和规律,研究结果为直线感应电机电磁设计提供了理论基础。同时,仿真结果对今后电机控制系统的设计有着重要意义。     

Rail brake system using a linear induction motor for dynamic braking

One type of braking system for railway vehicles is the eddy current brake. Because this type of brake has the problem of rail heating, it has not been used for practical applications in Japan. Therefore, we proposed the use of a linear induction motor (LIM) for dynamic braking in eddy current brake systems. The LIM reduces rail heating and uses an inverter for self excitation. We estimated the performance of an LIM from experimental results of a fundamental test machine and confirmed that the LIM generates an approximately constant braking force under constant current excitation. At relatively low frequencies, this braking force remains unaffected by frequency changes. The reduction ratio of rail heating is also approximately proportional to the frequency. We also confirmed that dynamic braking resulting in no electrical output can be used for drive control of the LIM. These characteristics are convenient for the realization of the LIM rail brake system. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 178(2): 29–38, 2012; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21209     

基于Ansoft的直线感应电机三维动态仿真

基于ANSOFT公司的Maxwell 3D的仿真环境建立了直线感应电机（LIM）的仿真模型。在所建立的模型基础上,对直线感应电机的基本特性和起动过程进行了动态仿真。仿真结果用来指导直线感应电机的理论研究以及本体和其控制系统的设计。     

A compensation method for the end effect of a linear induction motor

For the end effect of a linear induction motor (LIM), the authors propose a new concept that the end effect can be compensated for only by the supply of secondary current synchronized with the current of the LIM in front of the entry end of the LIM, without considering the flux density distribution in the LIM primary region. As a concrete method to supply the secondary current in front of the LIM, the authors propose the rotator with rare‐earth‐type permanent magnets which has a strong flux density without ohmic loss, and does not cause the power factor problem even for the influence of end effect. The results of analytical study on the numerical example of LIM designed for subways are as follows. This method can make the flux density and thrust density distribution in the LIM primary region almost entirely agree with those of the case without end effects. This method can compensate for the thrust, power factor, and efficiency of the LIM at the rated speed to coincide with the characteristics without end effect. There is no problem in the slip characteristic curves of the LIM with the compensator, although the compensator only rotates synchronizing with the frequency of the LIM. The effect of compensation becomes large in the lower slip. The force to rotate the compensator is very small in the suitable design. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 143(3): 58–67, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10132     

A study on technical feasibility of applying tubular linear induction motor to vertical movement

It is necessary for a linear induction motor (LIM) to have large thrust force in applications for the vertical movement. If it does not have sufficient thrust force, it cannot lift even itself. A ratio (thrust force/weight of motor), therefore, is the most important factor for the design of this motor. In this paper, assuming the LIM has no slot-effect and infinite length, a simple analytical model is introduced for steady-state operation. By comparison with the results of detailed numerical analysis, it is verified to be applicable for basic evaluation of the motor. The design of the motor for vertical movement is carried out and the ratio is maximized. The basic dimensions of a feasible motor are given for such application.     

Lightweight type linear induction motor and its characteristics

At the Institute for Posts and Telecommunications Policy, a postal transportation system has been studied. This system would make use of linear induction motor (LIM)-driven vehicles for transporting mail between post offices in the Tokyo Metropolitan area. The system would connect the main post offices in the Tokyo area with tunnels circularly constructed underground and would transport mail with linear induction motor-driven vehicles. In this study, it is found that if vehicle weight is reduced, climbing capability could be considerably improved. Accordingly, the potential for reducing the weight of vehicle-mounted LIMs has been explored, and a prototype lightweight LIM has been manufactured. This paper reports on the lightweight LIM and its characteristics.     

On-line gain-tuning IP controller using real-coded genetic algorithm

An integral proportional (IP) controller with on-line gain-tuning using real-coded genetic algorithm (GA) is proposed to control the mover position of a linear induction motor (LIM) servo drive system. First, the dynamic model of an indirect field-oriented LIM servo drive is derived. Then, a real-time GA is developed to search the optimal gains of the IP controller. The theoretic bases of the IP controller and real-time GA are described in detail. Moreover, the proposed control system is implemented in a PC-based computer control system to control the LIM for achieving high-precision position control with robustness. Finally, simulated and experimental results show that the proposed controller provides high-performance dynamic characteristics and is robust with regard to plant parameter variations and external load disturbance.