IGBT故障状态测试

介绍了变频器用IGBT模块的种类及故障判断的测试方法     

IGBT驱动故障状态下的高压变频器旁路运行技术探析

随着社会经济快速的发展,对于发电厂风机与水泵系统的整体水平的要求也就越来越高,其中最主要的就是在IGBT模块故障的处理,对其处理的效率直接关系到发电厂作业的质量和数量,更关系到社会科学技术的发展和进步,通过对发电厂水泵系统电控系统组成、IGBT驱动故障处理和预防措施的进一步的探讨。本文通过对IGBT驱动故障状态下高频变频器的运行进行分析,对其IGBT模块故障进行分析,更好的提出故障处理的方法。     

三电平大功率变频器故障诊断方法研究

三电平逆变器作为多电平逆变器的一种,在高压大功率场合获得了较为广泛的应用。但是功率器件的增加,提高了系统的故障率,因此,如何保证系统稳定运行便成为了一个重要研究的问题。本文针对三电平大功率变频器,通过理论分析和仿真,详细分析了主电路中的各功率器件在开路故障时的电路工作情况,故障典型特征及具体表现形式,并总结出了故障诊断规则。最后,基于三电平大功率变频器,对功率器件的开路故障进行了实验。实验结果进一步验证了对功率器件的故障分析及仿真结果。     

三电平变频器中的IGBT失效机理分析

从IGBT内部结构及其瞬态能量变化的角度，针对三电平变频器中的IGBT失效现象进行了较深入的分析。并以一台160kW的三电平变频器为具体对象，以试验结果为依据，解释分析了一些典型的IGBT失效机理，并提出了相应的有效解决措施。     

小孙学变频——第一讲 变频器的主电路（三）

3变频器的逆变器件-IGBT管 小孙对于低压电子技术是比较熟悉的,但对于变频器用的IGBT管,总觉得还了解得不大深入,这天晚上,他专门准备了一些关于IGBT管的问题,来向张老师请教。     

中等功率通用型变频器电路设计要点分析

随着变频器在现代工业中的广泛应用,变频器技术的研究也越来越受到重视。变频器电路是变频器中的重要组成部分,因此,对变频器电路的研究有着重要的意义。本文主要介绍了中等功率通用变频器电路设计三个方面的关键技术;主电路、IGBT驱动电路和控制电路。     

高压变频器在油田注水泵上的应用

本文对IGBT直接串联高压变频器的性能进行了简单的分析，介绍了高压变频器在油田注水泵上的应用实例，对高压变频器的节能效果进行了分析。     

通用变频器的故障类型及案例分析（一）第1讲通用变频器的过压故障及排除

变频器过压故障保护是变频器中间直流电压达到危险程度后采取的保护措施,这是电压型交-直-交变频器设计上的一大缺陷,在变频器实际运行中引起此故障的原因较多,可以采取的措施也较多,在处理此类故障时要分析清楚故障原因,有针对性的采取相应的措施去处理。     

Saber和Matlab在IGBT动态特性仿真中的应用研究

简要分析了目前常用的电力电子仿真软件Sabef和Madab的主要性能特点及在电力电子仿真中的适用程度。绝缘栅双极型晶体管（IGBT）广泛应用于中大功率变频器中,其开关特性决定了变频器的输出特性,由于大多数电机均为电阻电感性负载,因此应用以上两种仿真软件对电阻电感性负载的IGBT开关回路进行动态仿真研究比较,并通过实验证明,Saber软件中的IGBT模型输出特性更接近于真实情况。     

550kW／10kV同步电机变频节能改造

现阶段采用IGBT电压型高压变频器实现高压同步电机的速度及位置开环控制是很困难的。本文根据客户现场工况，提出了采用专用的JCS型IGBT高压变频器，实现高压同步电机拖动活塞式空压机的变频调速改造，取得了良好的运行效果和节能效果。     

Hierarchical fault modeling for linear analog circuits

This paper presents a hierarchical fault modeling approach for catastrophic as well as out-of-specification parametric faults in analog circuits. These include both, ac and dc faults in passive as well as active components. The fault models are based on functional error characterization. Case studies based on CMOS and nMOS operational amplifiers are discussed, and a full listing of derived behavioral fault models is presented. These fault models are then mapped to the faulty behavior at the macro-circuit level. Application of these fault models in an efficient fault simulator for analog circuits is also described.     

Fault diagnosis algorithm based on switching function for boost converters

A fault diagnosis algorithm, which is necessary for constructing a reliable power conversion system, should detect fault occurrences as soon as possible to protect the entire system from fatal damages resulting from system malfunction. In this paper, a fault diagnosis algorithm is proposed to detect open- and short-circuit faults that occur in a boost converter switch. The inductor voltage is abnormally kept at a positive DC value during a short-circuit fault in the switch or at a negative DC value during an open-circuit fault condition until the inductor current becomes zero. By employing these abnormal properties during faulty conditions, the inductor voltage is compared with the switching function to detect each fault type by generating fault alarms when a fault occurs. As a result, from the fault alarm, a decision is made in response to the fault occurrence and the fault type in less than two switching time periods using the proposed algorithm constructed in analogue circuits. In addition, the proposed algorithm has good resistivity to discontinuous current-mode operation. As a result, this algorithm features the advantages of low cost and simplicity because of its simple analogue circuit configuration.     

计算机辅助生成控制系统故障树

有关故障树生成方法的研究已经成为故障树分析研究中的一个重要分支，故障树的完善程度将直接影响系统可靠性的定性分析和定量计算。因此，故障树及故障树自动生成方法的开发研究具有非常现实和极其广泛的应用价值。本文分析了已有的控制系统故障树生成方法特点，提出一种计算机辅助故障树生成方法。通过系统元件的逻辑关系对所建立的元件故障模式数据库的搜索生成系统的故障树。该方法给出了元件故障模式的建立、元件问的关联方法、控制回路模板的建立方法以及故障树自动生成算法。最后，结合一个复杂系统故障树的生成验证了该方法的可行性和有效性。     

Availability requirement for a fault-management server in high-availability communication systems

This paper investigates the availability requirement for the fault management server in high-availability communication systems. This study shows that the availability of the fault management server does not need to be 99.999% in order to guarantee a 99.999% system availability, as long as the fail-safe ratio (the probability that the failure of the fault management server does not bring down the system) and the fault coverage ratio (probability that the failure in the system can be detected and recovered by the fault management server) are sufficiently high. Tradeoffs can be made among the availability of the fault management server, the fail-safe ratio, and the fault coverage ratio to optimize system availability. A cost-effective design for the fault management server is proposed.     

Fault models of CMOS circuits

A systematic procedure for fault modelling of CMOS circuits is described. It starts with the physical fault and produces a set of tables describing the logic behaviour of the gate. This set of tables is referred to as the fault model and includes truth tables, fault equivalence tables, fault coverage tables, and fault propagation tables. Starting with the procedure of fault modelling of simple combinational circuits, a method is advised for model generation of complex sequential structures. Application of fault modelling for yield evaluation and test pattern generation is considered, too.     

光学电流传感器测量电网接地故障信号的研究

针对光学电流传感器测量电网故障信号的选线方式,以测量中压电网单相接地的故障电流为例,提出了一种对地故障信号检测的可行方案。文中通过利用LabVIEW与Matlab混合编程的方式,模拟了电网接地的故障电流,运用小波算法将测量的故障信号去除噪声,并分析了去噪信号的各谐波分量,以供五次谐波选线。经过仿真验证,证明了去噪后的故障信号真实可靠,分析出的谐波频率所占比重也真实地反映了故障信号的成分。     

基于热点位置分类的电流互感器发热故障判别方法

针对变电设备故障发热特征选择、提取和故障类型判别问题,提出一种基于热点位置分类的电流互感器发热故障判别方法。首先运用CNN神经网络和YOLO融合算法完成电流互感器零部件检测为基础,建立二维坐标参考基准;然后采用PCNN分层聚类迭代方法分割出故障区域,并利用灰度质心法获取故障区域的热点等效中心;最后选择并提取热点等效中心到坐标原点的距离、角度等参数,应用这些参数判别热点位置的故障类别属性,从而实现电流互感器故障类型判别。结果表明,该判别方法准确率高达92,具有较好的实用性和推广性。     

Fault diagnosis technology based on Wigner–Ville distribution in power electronics circuit

Based on Wigner–Ville distribution similarity, a method of fault diagnosis is proposed for power electronics circuits. After setting up the module time–frequency matrices of Wigner–Ville distribution for all fault signals, the similarities between the module time–frequency matrices of the fault signal and the former standard are then calculated, thus arriving at the diagnosis according to the principle of maximum similarity. The simulation result of fault diagnosis of a thyristor in a three-phase full-bridge-controlled rectifier shows that the method can accurately identify the fault types as well as the location of the fault elements for power electronics circuits, and it has an excellent performance for noise robustness and calculation complexity. Therefore, it is quite practically valuable in the solution to the fault problems for power electronics circuits.     

Fault diagnosis and its prediction in wireless sensor networks using regressional learning to achieve fault tolerance

Due to the wide range of critical applications and resource constraints, sensor node gives unexpected responses, which leads to various kind of faults in sensor node and failure in wireless sensor networks. Many research studies focus only on fault diagnosis, and comparatively limited studies have been conducted on fault diagnosis along with fault tolerance in sensor networks. This paper reports a complete study on both 2 aspects and presents a fault tolerance approach using regressional learning with fault diagnosis in wireless sensor networks. The proposed method diagnose the different types of faulty nodes such as hard permanent, soft permanent, intermittent, and transient faults with better detection accuracy. The proposed method follows a fault tolerance phase where faulty sensor node values would be predicted by using the data sensed by the fault free neighbors. The experimental evaluation of the fault tolerance module shows promising results with R² of more than 0.99. For the periodic fault such as intermittent fault, the proposed method also predict the possible occurrence time and its duration of the faulty node, so that fault tolerance can be achieved at that particular time period for better performance of the network.     

Sensor fault detection algorithm based on credibility and neighbor-cooperation

To effectively detect whether a node was failure,one of the effective sensor fault detection methods was to compare historical data of suspicious node with its neighbors.The key points of this method were identification of suspicious nodes,as well as decision problem of sending timing for fault diagnosis messages.To this end,a sensor fault detection algorithm was presented based on credibility and neighbor-cooperation.Firstly,a credibility model to determine whether nodes are suspicious was established.Then suspicious nodes send fault diagnosis requests to neighbor nodes based on neighbor-cooperation.The sending timing was determined by equal probability time window.Finally,it could finish classification of fault condition and state judgment based on diagnosis responds of neighbor nodes.Simulation experiments show that this algorithm can achieve higher fault detection rate with less fault diagnosis times and low data congestion probability.