scholarly journals Dynamics Analysis of Misalignment and Stator Short-Circuit Coupling Fault in Electric Vehicle Range Extender

Processes ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1037
Author(s):  
Xiaowei Xu ◽  
Jingyi Feng ◽  
Hongxia Wang ◽  
Nan Zhang ◽  
Xiaoqing Wang
Keyword(s):  
Short Circuit ◽  
Complex Structure ◽  
Frequency Component ◽  
Element Analysis ◽  
Generator Rotor ◽  
Response Characteristics ◽  
Range Extender ◽  
Frequency Components ◽  
Coupling Fault ◽  
Fault Mechanism

Due to the complex structure and wide excitation of the range extender, the misalignment and stator short-circuit coupling fault can easily occur. Therefore, it is necessary to study the coupling fault mechanism of the range extender, analyze the cause of the fault and the fault evolution law, and research the coupling fault characteristics. To reveal the mechanism of misalignment and stator-short-circuit coupling fault, the misalignment mechanism was analyzed and the bending and torsion electromagnetic stiffness of the generator in the stator short-circuit fault was derived. Then the dynamic model of bending and torsion coupling for the generator was established. Furthermore, we used the Runge-Kutta method to study the vibration response characteristics of generator rotor under coupling fault. Then through finite element analysis, the feasibility of coupled fault diagnosis was verified. The results show that the response of the generator rotor not only has the frequency component of single faults, but also new frequency components such as 4.0 and 6.0 harmonic amplitudes of radial vibration and 3.0 harmonic amplitudes of torsional vibration, respectively.

Research on Detection Method of Transformer Interturn Short Circuit Based on Wavelet Analysis

2014 ◽  
Vol 521 ◽  
pp. 358-361
Author(s):  
Yu Sheng Quan ◽  
Zong Cheng Zhang ◽  
Guang Chen ◽  
Dai Juan Wang
Keyword(s):  
High Frequency ◽  
Short Circuit ◽  
Frequency Component ◽  
Diagnostic Methods ◽  
High Frequency Component ◽  
Transformer Winding ◽  
Ground Current ◽  
Frequency Components ◽  
Circuit Fault Diagnosis ◽  
Experimental Data Analysis

Distribution transformer is an important device in the power supply system, once its failure can cause power outages. According to statistics, 70% -80% of the transformer accident was caused by a short circuit between the transformer turns. Based on the large number of experimental data analysis and processing, a new inter-turn short circuit transformer diagnostic methods is proposed. In this paper, the ground current of transformer core as the signal source, Using wavelet multi-resolution technology the signal wavelet multiscale decomposition, the decomposition of different signals of the same scale, get the high frequency components of the signal, achieve short-circuit fault diagnosis between transformer winding turns by comparing the number of the high-frequency component contained in different signals in the decomposition of the same scale. To illustrate the effectiveness of the method, the paper through a series of experiments and data processing, verify the effectiveness and feasibility of the method.

The New Methodology of Diagnosis for Transformer Inter-Turn Short Circuit Based on Wavelet Analysis

2014 ◽  
Vol 672-674 ◽  
pp. 1155-1158
Author(s):  
Yu Sheng Quan ◽  
Ning Chen ◽  
Zi Jian Wang ◽  
Pu Xin Shi
Keyword(s):  
High Frequency ◽  
Short Circuit ◽  
Frequency Component ◽  
Diagnostic Methods ◽  
High Frequency Component ◽  
Transformer Winding ◽  
Frequency Components ◽  
Circuit Fault Diagnosis ◽  
Experimental Data Analysis ◽  
Transformer Core

Based on the large number of experimental data analysis and processing, a new inter-turn short circuit transformer diagnostic methods is proposed. In this paper, take the grounding current of transformer core as the signal source. Using wavelet multi-resolution technology the signal wavelet multiscale decomposition, we can get high frequency components of the signal. Achieve short-circuit fault diagnosis between transformer winding turns by comparing the number of the high-frequency component contained in different signals in the decomposition of the same scale.

Method for Predicting Unsteady Vibration of Gas Turbine Compressor Blades Under Subsonic Near-Stall Conditions

2014 ◽  
Vol 136 (12) ◽  
Author(s):  
Kazuyuki Yamaguchi ◽  
Yasuo Takahashi
Keyword(s):  
Gas Turbine ◽  
Incidence Angle ◽  
Low Frequency ◽  
Frequency Component ◽  
Compressor Blades ◽  
Element Analysis ◽  
Blade Vibration ◽  
Simple Method ◽  
Frequency Components ◽  
Gas Turbine Compressor

Wind tunnel tests and numerical calculations using computational fluid dynamics (CFD) analysis and structural finite element analysis were conducted to clarify the vibration characteristics of gas turbine compressor blades under subsonic near-stall conditions. The results show that discrete low-frequency components of pressure are created by variation of the separation region and that discrete high-frequency components are created by vortex shedding when the compressor blade incidence angle is in the stall region. The natural frequency component resonated by the random fluid force is dominant in blade vibration. The numerically calculated phenomena agree well with the measured phenomena. The vibration amplitude increases with the incidence angle and the Mach number, and it increases rapidly at higher angles. A simple method for predicting the vibration stress using static calculations is reasonably accurate.

Meshing Method of High Precision FEM in Large Complex Structural Simulations

2012 ◽  
Vol 195-196 ◽  
pp. 701-704
Author(s):  
Yan Hua Xue ◽  
Zhi Guang Wang ◽  
Xiao Hong Li ◽  
Xin Jiang
Keyword(s):  
Finite Element ◽  
Complex Structure ◽  
Width Ratio ◽  
Two Dimensional ◽  
Element Analysis ◽  
Large Complex ◽  
Mesh Density ◽  
Length Width ◽  
Complex Structural ◽  
Dimensional Element

Shing is playing an important role in the large complex structural FEM simulations; it has a direct effect on calculating precision of structural simulations. For increasing the calculation accuracy and analysis accuracy of complex structure, the finite element meshing problems is proposed on the finite element analysis of large complicated structures. The effects caused by element type, mesh density and intergradations on calculating precision are studied and discussed. A research argues that with length-width ratio of 1~2 and length-thickness ration of 1.5~4.5 of two-dimensional rectangular element, the quality of meshing method of two-dimensional element is above normal. As the height of one-dimensional element is equal to the sum of reinforcing rib height of outer panel and half the thickness of panel, more accurate results can be obtained.

Research on the Structural Performance of Large-Tonnage Gantry Crane

2013 ◽  
Vol 823 ◽  
pp. 247-250
Author(s):  
Jie Dong ◽  
Wen Ming Cheng ◽  
Yang Zhi Ren ◽  
Yu Pu Wang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Theoretical Calculations ◽  
Complex Structure ◽  
Early Period ◽  
Operating Conditions ◽  
Structural Performance ◽  
Gantry Crane ◽  
Element Analysis ◽  
Design And Manufacture

Because of the huge lifting weight and complex structure of large-tonnage gantry crane and in order to effectively design and review it, this paper aims to carry out a research on its structural performance based on the method of theoretical calculation and finite element analysis. During the early period of design, the method of theoretical calculations is adopted, and after specific design it comes the finite element analysis, so as to get the results of analysis under a variety of operating conditions, which illustrates that the structural design and review of large-tonnage gantry crane based on theoretical calculations and finite element are feasible, and also verifies that the method of finite element is an effective way to find a real dangerous cross-section, thus providing the basis for the design and manufacture of the crane structure.

Comprehensive design analysis of a 3D printed sensor for readiness assessment applications

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Tanushree Agarwal ◽  
Fatemeh Rahmani ◽  
Ishtique Zaman ◽  
Federico Gasbarri ◽  
Keivan Davami ◽  
...  
Keyword(s):  
Sensor Array ◽  
Short Circuit ◽  
Three Dimensional ◽  
Low Frequency ◽  
Optimal Placement ◽  
Chemical Plants ◽  
Readiness Assessment ◽  
Element Analysis ◽  
Content Type ◽  
Flexible Antenna

Purpose This paper aims to develop a comprehensive model of a magnetic sensor array that will be operational for a multitude of electric components in continuous and nonintrusive condition monitoring (CM) or in readiness assessment (RA) applications. Design/methodology/approach A universal nonintrusive model of a flexible antenna array is introduced to monitor and identify failures in electric machine drives. An adjustable sensor is designed to serve as a RA for a vast range of electrical elements in a typical power system by capturing the low-frequency radiated magnetic fields. Findings The optimal placement of the most sensitive radiated fields from several components has been discovered in this case study, enabling the detection of healthy current flow throughout. Thereafter, the short-circuit investigation, representing faulty situations, is implemented and compared with healthy cases. Practical implications This sensing technique can be used for nonintrusive CM of components that are out of reach and cannot have the sensor to be held around it such as components in offshore winds, wind energy generation and power and chemical plants. Originality/value The results are provided for three commonly used machines with a single sensor array with numerous settings. The three dimensional (3 D) finite element analysis is applied in the structuring of the sensor, detection of the optimum location and recognition of faults in the machines. Finally, based on the setup design, 3 D printing is used for the construction of the sensor array. Thus, the sensor array with fault detection avoids major component failures and increases system reliability/resiliency.

A Modified DFT-Based Channel Estimation Method for OFDM-RoF System

2014 ◽  
Vol 989-994 ◽  
pp. 3521-3525
Author(s):  
Li Qun Huang ◽  
Peng Zhang ◽  
Guang Yang
Keyword(s):  
Channel Estimation ◽  
High Frequency ◽  
Estimation Method ◽  
Frequency Component ◽  
High Frequency Component ◽  
Improved Method ◽  
Frequency Components ◽  
Influence Of Noise ◽  
Changing Rate ◽  
Better Than

In this paper, we present a modified discrete Fourier transform (DFT)-based channel estimation method. The conventional DFT-based method will produce additional high frequency component in the channel impulse response, and degrade the accuracy of channel estimation. The modified algorithm can eliminate additional high frequency components by extending the LS estimate in frequency domain with a symmetric signal of its own, and selects the useful paths by calculating the changing rate of energy. Thus, the proposed algorithm become more accurate. The simulation results show the new algorithm can reduce the influence of noise on channel estimation efficiently, and the performance of the improved method is better than the LS and conventional DFT algorithm.

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