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Документ Open circuit fault diagnosis for a five-level neutral point clamped inverter in a grid-connected photovoltaic system with hybrid energy storage system(Національний технічний університет "Харківський політехнічний інститут", 2023) Abdellah, A.; Larbi, M'hamed; Toumi, D.Recently, the number of high and medium voltage applications has increased dramatically. The connection between these different applications requires series-parallel combinations of power semiconductors. Multilevel converter topologies provide major advantages to these applications. In this paper, a grid-connected photovoltaic system with a hybrid energy storage systemusing a five-level neutral point clamped inverter is studied. Although the multilevel inverter has many advantages over the two-level inverter, it has a high probability of experiencing an open circuit fault. In this context, the five-level inverter has 24 controllable switches, one of which may experience an open circuit fault at any time. Therefore, it plays an important part in the reliability and probustness of the whole system. The novelty of this paper presents an approach to accurately detect the open circuit fault in all insulated gate bipolar transistors of a five-level neutral point clamped inverter in a photovoltaic power generation application with a hybrid energy storage system. Purpose. Before using fault-tolerant control to ensure service continuity, fault diagnosis techniques must first be used, which are the crucial phase of reliability. Methods. A detection method based on the maximum and minimum error values is proposed. These errors are calculated using the expected and measured line-to-line pole voltages. Results. The open circuit fault detection method is implemented using MATLAB/Simulink. Simulation results showed the accuracy of detecting the open circuit fault in all insulated gate bipolar transistors in a short time. Moreover, this method is adaptable to several applications and is also robust to transient regimes imposed by solar irradiation and load variations.Документ Methods of detection of temperature factors affecting traffic safety of railway transportation and risk analysis(Національний технічний університет "Харківський політехнічний інститут", 2022) Bekirova, Lala; Bayramov, AladdinThe article is dedicated to the investigation of internal and external factors affecting traffic safety of railway transport, including researching and solving ever-present issue of investigating, reducing and eliminating human factors, emergency situations and other impacts through complex methods and means. The technical state of wagons, one of the important components for traffic safety in railway transport, methods and means of detecting faults during their diagnostics, and making right decisions according to the situation are investigated. Diagnostics of the state of wagons is carried out through the method of remote measurement at measuring points installed at certain distances with a certain rule. At measuring points, the temperatures of tire boxes are investigated according to the normal limits, and risk status is assessed according to the comparison results. Accuracy and stability of diagnostics are very important for safe operation. In order to make right decisions, assessment of measurement errors of temperature factors, performing self-monitoring and correction, execution of the algorithm based on repeated measurements and points, carrying out comparison with norm limits, and making decisions provided that they are confirmed are presented. Based on Fuzzy Logic in Matlab environment, assessment of processing risks and suitable combinations are presented.Документ Photovoltaic fault diagnosis algorithm using fuzzy logic controller based on calculating distortion ratio of values(Національний технічний університет "Харківський політехнічний інститут", 2023) Lahiouel, Younes; Latreche, Samia; Khemliche, Mabrouk; Boulemzaoud, LokmaneThe efficiency of solar energy systems in producing electricity in a clean way. Reliance on it in industrial and domestic systems has led to the emergence of malfunctions in its facilities. During the operating period, these systems deteriorate, and this requires the development of a diagnostic system aimed at maintaining energy production at a maximum rate by detecting faults as soon as possible and addressing them. Goal. This work proposes the development of an algorithm to detect faults in the photovoltaic system, which based on fuzzy logic. Novelty. Calculate the distortion ratio of the voltage and current values resulting from each element in the photovoltaic system and processing it by the fuzzy logic controller, which leads to determining the nature of the fault. Results. As show in results using fuzzy logic control by calculating the distortion ratio of the voltage and current detect 12 faults in photovoltaic array, converter DC-DC and battery.Документ Photovoltaic system faults diagnosis using discrete wavelet transform based artificial neural networks(Національний технічний університет "Харківський політехнічний інститут", 2022) Bengharbi, Abdelkader Azzeddine; Laribi, Saadi Souad; Allaoui, Tayeb; Mimouni, AminaIntroduction. This research work focuses on the design and experimental validation of fault detection techniques in grid-connected solar photovoltaic system operating under Maximum Power Point Tracking mode and subjected to various operating conditions. Purpose. Six fault scenarios are considered in this study including partial shading, open circuit in the photovoltaic array, complete failure of one of the six IGBTs of the inverter and some parametric faults that may appear in controller of the boost converter. Methods. The fault detection technique developed in this work is based on artificial neural networks and uses discrete wavelet transform to extract the features for the identification of the underlying faults. By applying discrete wavelet transform, the time domain inverter output current is decomposed into different frequency bands, and then the root mean square values at each frequency band are used to train the neural network. Results. The proposed fault diagnosis method has been extensively tested on the above faults scenarios and proved to be very effective and extremely accurate under large variations in the irradiance and temperature.