共查询到20条相似文献,搜索用时 46 毫秒
1.
2.
3.
4.
5.
6.
7.
8.
板级电路故障诊断过程复杂,故障征兆和故障原因之间存在着许多不确定因素,建立精确的故障诊断系统存在着许多困难,针对这种情况,本文提出了基于模糊神经网络,利用模糊逻辑和神经网络相结合建立故障诊断系统的方法,并以某电路板为研究对象对该方法作了验证。 相似文献
9.
级联型多电平逆变器由于其模块化结构、便于生产高度、更换容易等特点,受到电力电子工程技术人员的广泛关注。本文通过对于级联型多电平逆变器几种典型的控制方法的分析比较,提出了一种改进多载波PWM控制方法。该方法通过改变载波的幅值,使级联逆变器的各个逆变单元开关规律相同,并使所有的开关器件的损耗一致,有利于逆变单元的统一设计和可靠运行。 相似文献
10.
11.
The increased component requirement to realise multilevel inverter (MLI) fallout in a higher fault prospect due to power semiconductors. In this scenario, efficient fault detection and diagnosis (FDD) strategies to detect and locate the power semiconductor faults have to be incorporated in addition to the conventional protection systems. Even though a number of FDD methods have been introduced in the symmetrical cascaded H-bridge (CHB) MLIs, very few methods address the FDD in asymmetric CHB-MLIs. In this paper, the gate-open circuit FDD strategy in asymmetric CHB-MLI is presented. Here, a single artificial neural network (ANN) is used to detect and diagnose the fault in both binary and trinary configurations of the asymmetric CHB-MLIs. In this method, features of the output voltage of the MLIs are used as to train the ANN for FDD method. The results prove the validity of the proposed method in detecting and locating the fault in both asymmetric MLI configurations. Finally, the ANN response to the input parameter variation is also analysed to access the performance of the proposed ANN-based FDD strategy. 相似文献
12.
Switch fault detection and diagnosis in space vector modulated cascaded H-bridge multilevel inverter
Nithin Raj Tushar Kale Anjali Anand Jagadanand G Saly George 《International Journal of Electronics》2018,105(12):1977-1992
This article investigates the development and online implementation of the power switch open-circuit fault detection and diagnosis in symmetric cascaded H-bridge multilevel inverter. A mathematical modelling technique is presented to understand the effect of the fault on the bridge voltages and output voltage. The modelled values of the output voltage, simulation results and experimental results indicate that the fault diagnostic methods based on the output voltage as the diagnostic feature have certain ambiguity in identifying the fault switch, since the output voltage waveform and its features remain the same for a group of switches under the fault condition. In order to overcome this, fault detection and diagnosis method based on the mean values of the bridge voltages is proposed in this article, which identifies the faulty switch pair and H-bridge in which the fault has occurred. Further, this method has been experimentally validated on a five-level space vector modulated symmetric cascaded H-bridge multilevel inverter. 相似文献
13.
Bidyut Mahato Saikat Majumdar Kartick Chandra Jana 《International Journal of Electronics》2019,106(8):1200-1215
Multilevel inverter (MLI) generates stepped voltage with appropriate switching combination of power devices, thus restraining the requirement of filter circuit for an efficient power conversion. MLIs are attracting due to some of the major features like economic cost, installation space, bulkiness, complexity along with its enormous applications in industries like cement factory, ceramic industry, aerospace applications etc. In this paper, a single-phase generalised inverter based on five different algorithms is proposed that uses the minimum of overall power components. The presented topology can be used in low and medium voltage applications. To verify the simulation results obtained by MATLAB/Simulink, DS1103 controller is used to generate the corresponding experimental results by developing a prototype model in the laboratory. Nevertheless, a comparative assessment for the different required components of the proposed topology is carried out with some recently developed topologies. Reduction in power switches, driver circuits and DC voltage sources reduces the size, cost, complexity and enhances the overall performance. In addition, level per switch ratio is added in this paper to decide the effectiveness of the proposed topology. 相似文献
14.
15.
介绍了应用小波变换法与BP神经网络相结合实现模拟电路故障诊断的方法。应用小波变换法作为故障信号的预处理器,提取故障特征量,减小了BP神经网络的规模。该方法提高了神经网络收敛的速度以及故障类别识别的准确度,具有一定的应用价值。 相似文献
16.
随着社会的不断发展和完善,变频器的应用越来越广泛。传统的设备调速方法效率比较低,并且损耗相对比较大,应用变频器可以有效解决这些问题。但是在对变频器实际应用的过程当中,经常有故障出现,从而对变频器的使用效率产生比较严重的影响,所以需要解决这些问题。文章对此展开分析。 相似文献
17.
18.
BP神经网络在电子战效能评估中的应用 总被引:1,自引:0,他引:1
利用BP神经网络算法对电子对抗干扰效果进行评估,根据干扰效果评定的诸因素的隶属函数确定其隶属度,以此作为神经网络输入层数据.然后,根据选定的训练样本对所构造的三层BP神经网络进行训练,再运用几组典型干扰对抗效果实验数据对该BP神经网络性能进行检验.结果表明BP网络已经训练好,用此BP神经网络评估电子对抗干扰效果是合理的,该方法减少了评估中的人为因素,使得评估结果更为可信. 相似文献
19.