集成式电静压伺服机构直流侧电压振荡抑制

电静压伺服机构属于泵控液压系统,驱动控制器将直流电转换为三相交流电以驱动伺服电泵旋转,进而使伺服机构产生往复运动。驱动控制器与伺服机构进行集成化设计可以有效降低强电电磁辐射,减小电缆长度,减少电接触点。但是在集成化设计中,需要降低直流侧支撑电容容量以减小驱动控制器体积。小容量支撑电容情况下,伺服机构作动时直流侧电压会出现不稳定振荡现象。通过主动缓冲的方法降低直流侧电压振荡幅度,满足集成化设计对直流侧电压稳定性和驱动控制器小体积的要求。     

电压源型PWM整流器直流母线电压的消抖方法

直流母线电压的稳定性是PWM整流器的一个重要指标。在电网电压不平衡且(或)含有低次电力谐波时,传统的控制方法不能消除直流母线电压的抖动。为解决这一问题,首先深入分析了电网电压不平衡且含有5次、7次谐波分量对电压源型PWM整流器的直流母线电压稳定性的影响;进而提出了一种基于比例积分-谐振(PI-R)的控制策略,并详细分析了电流控制指令计算和PI-R控制器的设计方案。1 MW PWM整流器的仿真结果表明,所提出的控制策略能显著抑制直流母线电压的波动,并提高系统的安全运行性能。     

一种平滑 DFIG有功功率波动的混合控制策略的研究

提出了一种在超同步转速范围内平滑双馈异步风力发电机（ DFIG）转子侧有功功率波动的混合控制策略。该策略在传统的双馈异步风力发电机组控制基础上,引入了变桨距和直流侧电压混合控制。变桨距控制用来平滑有功功率波动的低频分量;直流侧电压控制的给定值叠加一个随功率波动变化的偏差电压,用来平滑有功功率波动的高频分量。在Matlab/Simulink平台上,搭建了DFIG构成的风力发电系统,分别采用传统控制策略和文中提出的混合控制策略进行仿真,结果表明,混合控制策略有效平滑了发电机转子侧有功功率的波动。     

便携式机车牵引电机绝缘检测仪的设计

绝缘检测试验是鉴定机车牵引电机介电强度有效而直接的方法,它可以明确判断电机绝缘是否处于良好状态。该绝缘检测仪采用直流高压泄漏电流来检测牵引电机的绝缘状态,用泄漏电流的非线性增长来判断电机的绝缘性,从而达到对电机绝缘质量控制;测试系统采用具备12位测量精度的高速A/D转换芯片MAX197进行数据采集,并以Windows CE5.0作为嵌入式操作系统;该绝缘检测仪输出过程具有稳压环节,不受电网电压和分载波动的影响,并且结构简单,携带方便,单人操作,安全可靠,适用于检测具有机械损伤的牵引电机主绝缘状态[1]。     

A fault isolation filter design using left eigenstructure assignment scheme

This paper presents a novel fault isolation filter design method using left eigenstructure assignment scheme proposed by the first author et al. The proposed method shows good performance of fault isolation with an exact eigenstructure assignment and guarantees that the corrupted γ faults can be isolated simultaneously when the number of available output measurements are equal to or larger than (γ+l). A numerical example for the fault isolation filter is also included.     

Intelligent fault monitoring and diagnosis in electrical machines

The aim of this paper is to develop an intelligent diagnosis method for fault detection and isolation in induction motors. We consider failures in three components of induction motor: bearing, stator winding and rotor winding. Firstly, a model-based nonlinear observer in the proposed method is designed based on available information. The fault detection decision is carried out by comparing the model-based observer speed with their signatures. Secondly, multiple state observers are constructed based on possible fault function set. The fault isolation decision is made by checking each residual generated by observer state estimation. Finally, simulation tests are given to verify the effectiveness of the proposed fault diagnosis scheme.     

基于孤立森林算法的风电齿轮箱轴承故障检测方法

为精准检测齿轮箱轴承故障,实时进行有效监测以保证风电齿轮箱健康运行,提出一种基于孤立森林算法的风电齿轮箱轴承故障检测方法.首先,以齿轮箱轴承温度为故障检测模型的输出变量,采用多尺度图相关算法选择输入变量;然后,提取输入变量的均方根和包络线进行自组织映射神经网络特征融合;最后,以融合值为模型输入量,使用孤立森林算法进行异...     

CRH3型动车组牵引传动系统的直接转矩控制研究

为了研究高速动车组的具体模型结构及其牵引传动控制系统,采用直接转矩控制(DTC)系统控制异步牵引电机,建立了CRH3型高速动车组牵引传动系统的Matlab/simulink仿真模型,整流部分由四象限脉冲整流器输出3 000 V左右平滑的直流电压,逆变部分由直接转矩控制系统驱动牵引电机。该系统能根据CRH3型动车组的牵引、制动曲线模拟动车组牵引、惰行、制动等各种运行工况。整个运行过程中系统的谐波较小,电压/电流相位差基本能保持在同相或反相运行,功率因数基本接近1;在网压波动和突然失电情况下,机车也基本能保持恒速运行。最后,将该模型仿真结果与京津城际高速铁路的部分数据进行了对比验证。研究结果表明,该模型建模基本正确,同时系统具有良好的稳态和动态性能,验证了直接转矩控制方法的有效性。     

Development of methods for evaluating traction fluids

Two methods have been developed for evaluating the performance of potential traction fluids. One method employed a 4-ball machine modified to measure torque and slip under rolling conditions. Aadvantages of the technique were the cheapness and replaceability of the rolling components, and the small amount of test fluid required. The other method was developed using a commercial traction drive, a Kopp variator; it was instrumented to allow measurement of torque and slip. There was a satisfactory correlation between results obtained in both pieces of apparatus for several fluids.Fluids of widely varying compositions were examined in the 4-ball machine and clear indications of the necessary features for a good traction fluid are discussed. In general, fluids with higher pressure-viscosity coefficients were better tractants. There was a clear trend towards better traction with compositions containing high proportions of naphthenic material, an observation which confirmed the patent literature claims for such classes of compounds.     

四轮驱动汽车牵引力控制算法

提出了实用的四轮驱动汽车牵引力控制算法。在确定控制系统结构的基础上,设计了车速估算算法、油门位置PI控制器和制动门限控制算法。为实现牵引力控制算法的快速开发,建立由传感器、执行器、工控机、采集卡和输入输出电路组成的车载快速开发平台。硬件在环试验和道路试验表明:传感器能准确检测输入信号,控制算法能根据输入信号生成控制指令,执行器能快速、准确产生动作以消除驱动轮过度滑转。     

环鸣法声速仪超声波发射/接收电路设计

通过对海洋环鸣法声速仪的深入分析,阐述环鸣法声速仪的工作原理,设计了1种的超声波发射/接收电路。重点研究了高压窄带脉冲产生电路、MOS管驱动电路以及匹配网络。对研制的电路进行了性能分析,所有的电子器件均无过热现象,获得了较为理想的超声波。整个电路结构简单,成本相对低廉,操作安全,易于模块化实现,符合待定检测的要求。     

大功率直驱风力发电系统直流侧电压复合控制策略

在开发大功率直驱型风力发电双脉宽调制（PWM）变流器的过程中,为有效抑制由于电机侧有功功率及电网电压的突变而导致的直流侧电压的大幅波动,提出了一种闭环控制与前馈控制相结合的直流侧电压复合控制策略,即在电流控制环中引入机侧有功功率和电网电压前馈控制。仿真实验有效验证了该方法的可行性。研究结果表明,这种控制策略与传统单纯的直流侧电压闭环控制相比,有更快的响应速度和更强的抗扰性能,有效地提高了系统的鲁棒性。     

太阳翼驱动机构的模糊动态故障树分析

作为航天器重要的组成部分之一的太阳翼驱动机构,故障频发,它的可靠性研究凸显出重要的价值。根据太阳翼驱动机构的组成和工作原理,建立了相应的动态故障树。考虑到现实中太阳翼驱动机构的故障现象、故障状态与故障原因等存在着大量的不确定性,将模糊集理论引入动态故障树分析中,采用三角模糊数表示太阳翼驱动机构故障树的各个底事件的失效参数,将 截集理论与区间运算相结合,对太阳翼驱动机构进行模糊动态故障树分析,从而得到系统的顶事件模糊发生概率与各个底事件的模糊概率重要度,并对模糊概率重要度进行分析,得出太阳翼驱动机构中的关键部件为系统中的轴承及谐波减速器,找到了系统的薄弱环节。     

一种新型线电压直接脉宽调制方法

本文在研究2电平逆变器模型及其经典脉宽调制（PWM）方法基础上，提出一种新型的线电压直接脉宽调制（DPWM）方法。这种方法与传统的以相电压为参考波的脉宽调制方法不同，它以三路线电压作为参考波形，直接确定逆变器开关管在每个斩波周期内的导通时间。该方法原理清晰易于实现，可以使逆变器的直流电压利用率达到最高，仿真和实验取得了满意的控制效果。     

Fault diagnosis of the polypropylene production process (UNIPOL PP) using ANFIS

The performance of a chemical process plant can gradually degrade due to deterioration of the process equipment and unpermitted deviation of the characteristic variables of the system. Hence, advanced supervision is required for early detection, isolation and correction of abnormal conditions. This work presents the use of an adaptive neuro–fuzzy inference system (ANFIS) for online fault diagnosis of a gas-phase polypropylene production process with emphasis on fast and accurate diagnosis, multiple fault identification and adaptability. The most influential inputs are selected from the raw measured data sets and fed to multiple ANFIS classifiers to identify faults occurring in the process, eliminating the requirement of a detailed process model. Simulation results illustrated that the proposed method effectively diagnosed different fault types and severities, and that it has a better performance compared to a conventional multivariate statistical approach based on principal component analysis (PCA). The proposed method is shown to be simple to apply, robust to measurement noise and able to rapidly discriminate between multiple faults occurring simultaneously. This method is applicable for plant-wide monitoring and can serve as an early warning system to identify process upsets that could threaten the process operation ahead of time.     

PWM-switching pattern-based diagnosis scheme for single and multiple open-switch damages in VSI-fed induction motor drives

This paper deals with a fault detection technique for insulated-gate bipolar transistors (IGBTs) open-circuit faults in voltage source inverter (VSI)-fed induction motor drives. The novelty of this idea consists in analyzing the pulse-width modulation (PWM) switching signals and the line-to-line voltage levels during the switching times, under both healthy and faulty operating conditions. The proposed method requires line-to-line voltage measurement, which provides information about switching states and is not affected by the load. The fault diagnosis scheme is achieved using simple hardware and can be included in the existing inverter system without any difficulty. In addition, it allows not only accurate single and multiple faults diagnosis but also minimization of the fault detection time to a maximum of one switching period (T(c)). Simulated and experimental results on a 3-kW squirrel-cage induction motor drive are displayed to validate the feasibility and the effectiveness of the proposed strategy.     

Design of H(infinity) robust fault detection filter for linear uncertain time-delay systems

In this paper, the robust fault detection filter design problem for linear time-delay systems with both unknown inputs and parameter uncertainties is studied. Using a multiobjective optimization technique, a new performance index is introduced, which takes into account the robustness of the fault detection filter against disturbances and sensitivity to faults simultaneously. The reference residual model is then designed based on this performance index to formulate the robust fault detection filter design problem as an H(infinity) model-matching problem. By applying robust H(infinity) optimization control technique, the existence condition of the robust fault detection filter for linear time-delay systems with both unknown inputs and parameter uncertainties is presented in terms of linear matrix inequality formulation, independently of time delay. In order to detect the fault, an adaptive threshold which depends on the inputs is finally determined. An illustrative design example is used to demonstrate the validity of the proposed approach.     

Sensor fault diagnosis based on energy balance evaluation: application to a metal processing

This paper deals with the design of a residual generator for fault detection and isolation in the dynamic closed-loop systems based on the balance of energy which "enters" and "leaves" plants. The main contribution of this paper consists in developing a suitable fault detection and isolation technique to detect faults in single-input single-output closed-loop system based on major signals without the requirement of an accurate static or dynamic model. Indeed, in the absence of conventional input-output models, the proposed method involves the on-line energy balance evaluation to detect a sensor fault. The application to the monitoring of a galvanizing line in steel industry shows the effectiveness of the suggested approach when a sensor fault occurs.     

普通公路隧道机电设施故障检测方法研究

针对现有公路隧道机电设施故障检测中存在故障信号处理效果差的问题,提出一种新的普通公路隧道机电设施故障检测方法。从技术性能指标、运营效果指标 2 个角度着手,计算检测指令执行所需的权重比数值,完成普通公路隧道机电设施的检测指标选取。在此基础上,分析普通公路隧道机电设施故障信号的表现特点,并实施集中化采集,通过提取特征向量的方式,获得理想化的故障行为识别结果,实现故障检测方法的设计。实例分析结果显示,与未经过滤的机电设施声波信号相比,经所提方法过滤后的声波信号明显更加贴合常规声波信号的变化行为,能够提升隧道机电设施的利用率。     

Solid-state transformer-based new traction drive system and control

A new type of traction drive system consisting of solid-state traction transformer (SSTT), inverter unit, auxiliary inverter, traction motor and other key components is built in order to suit the demand of developing the next-generation electric traction system which will be efficient and lightweight, with high power density. For the purpose of reducing system volume and weight and improving efficiency and grid-side power quality, an efficient SSTT optimized topology combining high-voltage cascaded rectifiers with high-power high-frequency LLC resonant converter is proposed. On this basis, an integrated control strategy built upon synchronous rotating reference frame is presented to achieve unified control over fundamental active, reactive and harmonic components. The carrier-interleaving phase shift modulation strategy is proposed to improve the harmonic performance of cascaded rectifiers. In view of the secondary pulsating existing in a single-phase system, the mathematical model of secondary power transfer is built, and the mechanism of pulsating voltage resulting in beat frequency of LLC resonant converter is revealed, so as to design optimum matching of system parameters. Simulation and experimental results have verified that the traction system and control scheme mentioned in this paper are reasonable and superior and that they meet the future application requirements for rail transit.