bluuebunny/crossref_metadata_2025_split huggingface dataset:
The online diagnosis of internal insulation fault of capacitance voltage transformers based on machine learning
Authors: Wei Wei , Peng Tao , Fang Yi , Ye Li 
Published: June 2022

Abstract
In order to diagnose internal insulation faults of CVT in time, an online diagnosis method for the internal insulation performance of CVT is proposed in this paper. The relationship between CVT insulation performance and measured data is obtained by analyzing CVT internal insulation structure and transfer function. After constructing an appropriate eigenvector by the inter-group correlation amplitude parameter of CVT, three methods of SVM, Bayes, and KNN are used as classifiers for insulation fault diagnosis. The experiment result shows that KNN method can effectively diagnose internal insulation faults with an accuracy rate of 100%.
Analysis and Research on the Reasons for the Increase of Com ponents in 500kV Transformer Oil
Authors: Li Rui , Chen LiangYuan , Li DaJian , Zhang Lei 
Published: June 2022

Abstract
This paper analyzes the cause of the defect of component growth in a 500kV transformer oil. First, the historical operation of the main transformer is analyzed, and then the oil chromatography data is studied. The A-phase online chromatography shows that the acetylene content is in good agreement with the offline chromatography detection, showing an increasing trend. The disintegration inspection of the main phase A phase found that there were two obvious discharge breakdown points in the inner paper tube of the low-voltage coil. According to the analysis results, the A-phase transformer should be managed and controlled, especially the oil chromatography tracking period (once every two weeks) should be shortened, and the load should be controlled if necessary.
Research on cross-region interconnection detection method of abnormal data in power monitoring system
Authors: Bin Dongmei , Ling Ying , Yu Tong , Yang Chunyan , Liu Muxian , Chen Haiguang 
Published: June 2022

Abstract
When conventional methods collect cross region interconnection detection data of power monitoring system, one data has multiple signal strengths, resulting in low detection rate and high false alarm rate of cross region interconnection abnormal data. Therefore, a cross region interconnection detection method of abnormal data in power monitoring system is proposed. Divide the cross region interconnection scene types of power monitoring system, make the detection end send data packets to the security partition corresponding to different scenes, and Gaussian filter the signals received in the security partition, and only retain the signals with probability distribution density function of [0.5,1]; Convert multiple signal strength indications of MAC address into one, so that the security partition only responds to the MAC address, obtains the MAC address detection data, and inputs it into the deep confidence network after preprocessing. If the MAC address matches successfully, it is judged that there is cross region interconnection in the power monitoring system, and the cross region interconnection detection of abnormal data is completed. The cross region interconnection alarm data provided by a power Co., Ltd. is selected as the experimental data, and the comparative experiment is set. The results show that the design method improves the abnormal data detection rate, reduces the false alarm rate, and ensures the detection accuracy of large-scale cross region interconnection data.
Analysis of evaluation index for the electron laminar properties in the electron optical system
Authors: Zhang Jian , Geng Zhihui , Jin Qi 
Published: June 2022

Abstract
In the simulation of the electron optical system of vacuum electronic devices, the evaluation of the electron laminar properties can only be judged by observing the electron trajectories. The quantitative evaluation index parameters for the electron laminar properties is lacking in the electron optical software. To achieve a quantitative analysis of the electron laminar properties in Egun simulations, the crossover rate evaluating the laminar properties of electron properties is presented in this paper. The simulation results show that the crossover rate index can accurately and quantitatively evaluate the quality of the electron laminar properties. When the crossover rate of electron properties is less than 3%, the designed electron optical system meets the engineering requirements. The crossover rate can be used as the target parameters in the automatic optimization of electron optical system.
Research on performance parameter degradation of high voltage and high power IGBT module in power cycling test
Authors: Li Cui , Sheng Li Yao , Xu Liu Jun , Qiang Shao Hua , Chen Zhong yuan , Yuan Li Jin 
Published: June 2022

Abstract
In Power cycling test, for low-voltage and low-power modules, it is generally considered that the saturation voltage drop VCE(sat) reaches 105% of the initial value or the thermal resistance Rth reaches 120% of the initial value as the basis for judging the failure of the IGBT module. However, since the high-voltage and high-power IGBT modules are connected in parallel with multiple chips, there are differences in the aging speed of the chips, and the degradation of individual chips has little influence on the parameters of the entire module, so the failure judgment standard may not be applicable. In order to obtain the degradation of the characteristic parameters of the high-voltage and high-power IGBT module in the power cycle test, this paper selects the 6500V/600A IGBT module as the research object, adopts the experimental method of constant junction temperature fluctuation, and tests the module parameters after every cycle 20,000 times until the module fails. Three failure modes were found through the test: GE failure, CE failure, GE and CE failure. And the degradation law of the parameters of the high-voltage and high-power IGBT module during the power cycling test was obtained.
System design and research of multi-channel electroacupuncture instrument
Authors: Liang Chuanqi , Zhang Yulin , Li Yan 
Published: June 2022

Abstract
This paper introduces the development history, working principle, curative effect under different output waveforms and the hardware and software design of the system. The proportional constant current output circuit is analyzed in detail. A system structure of electroacupuncture instrument based on modular design is proposed. The system structure mainly includes multi-channel electroacupuncture control module and display control module, which are connected through CAN bus. Multi-channel electroneedle control module adopts embedded processor and real-time operating system design, display control module is application level processor, running embedded Linux system design. The system has reasonable structure design and high expansibility, which is convenient for further research.
Design of Parallel Hybrid Active Power Filter
Authors: Wang Yan , Yang Ruijie 
Published: June 2022

Abstract
With the rapid development of social economy, electric energy plays an indispensable role in social life and has become an important symbol of the country’s comprehensive national strength. However, with the rapid development of power electronic technology, many nonlinear loads appear in the power system, which has become the most important harmonic source in the power system. Harmonics will not only affect the normal operation of various electrical equipment, but also damage the peripheral communication system and equipment of public power grid. Therefore, we must control the harmonics in the power grid. The traditional treatment scheme is to use LC passive filter (PF), but it can only filter out harmonics of a specific number of times. In addition,it is sensitive to power grid parameters, may produce resonance, so that the harmonics are amplified, and the volume of the filter device is huge. In order to overcome the above problems, active power filter (APF) appears, which can dynamically compensate harmonics according to harmonic frequency and size, and has excellent flexibility and practicability. However, in terms of cost, the cost of APF with the same capacity is much higher than that of PF. Therefore, based on the respective characteristics of PF and APF, this paper makes an in-depth research and design of hybrid active power filter (HAPF). In this system, the passive filter completes the main harmonic compensation and reactive power improvement, while the active filter is used to help the passive filter overcome the disadvantage of easy resonance.
Research on Photoelectric Detection Performance Based on Pb Se Quantum Dots
Authors: Liu Hao , Yang Junhong 
Published: June 2022

Abstract
Quantum dot materials have the advantages of low cost, wide spectral response and good photostability, and are widely used in optoelectronic fields such as light-emitting diodes and photodetectors. Quantum dots are the key materials for the next generation of new semiconductor optoelectronic devices. The direct integration of nano-quantum dots with silicon-based materials can simplify the fabrication process of optoelectronic devices. The environmental stability of lead selenide (PbSe) quantum dots is poorer than that of lead sulfide (PbS) quantum dots, which limits its application in optoelectronic devices. In this paper, we combine lead selenide quantum dots with silicon-based photovoltaic junction field effect transistors, and introduce halides in the synthesis process to improve the stability of quantum dots in air. We analyze and study the performance of this new type of near-infrared quantum dot photodetector, and study the influence of factors such as channel area and quantum dot size on the performance of the detector, which provides ideas for further optimizing the photodetection performance.
Analysis of defrosting system failure of ship low temperature cold storage
Authors: Wang Yanyang , Hu Linxiang , Wang Heng , Liu Chongchong 
Published: June 2022

Abstract
The frosting of the evaporator of the ship’s low-temperature cold storage will affect the heat exchange performance of the evaporator operation, the stability of the low-temperature cold storage of the ship’s food security and the effect of food refrigeration. Therefore, the evaporator coil of the low-temperature cold storage needs to be defrosted regularly. The low-temperature refrigeration system of a ship adopts the defrosting mode of electric heating. The lower the temperature of the low-temperature warehouse, the more important the thermal effect of defrosting is. This paper puts forward a technical innovation scheme for the design of the ship’s cold storage and the defrosting control mode, which can provide a reference for the design of the ship’s low-temperature refrigeration system and the defrosting of the low-temperature cold storage.
Study on Single Crystal Holmhertz Underwater Acoustic Transducer
Authors: Chen Geng , Liu Hao 
Published: June 2022

Abstract
According to the theoretical calculation and finite element simulation, a Holm-Hertz transducer is designed. When the resonant frequency of the outer liquid cavity of the transducer is consistent with the resonant frequency of the piezoelectric ceramic stack, the maximum transmit voltage response(TVR) is obtained. After the electrical material was replaced with a new relaxation ferroelectric single crystal piezoelectric material PIN-PMN-PT, the resonant frequency of the transducer was reduced, and the liquid cavity structure was redesigned. Single crystal, can significantly reduce the resonant frequency of the transducer, while significantly increasing the transmit voltage response.
Ultra-Broadband Full-Space Function-Integrated Stealth Antenna System Based on Metasurface
Authors: Wang Zan-Yang , Wang Guang-Ming , Cui Xing-Shuo 
Published: June 2022

Abstract
In this paper, an ultra-broadband full-space function-integrated stealth antenna is proposed based on metasurface (MS). After x-polarized and y-polarized spherical wave passing through the MS, the MS converts the y-polarized spherical wave into the x-polarized vortex wave in transmission space, deflects and focus the x-polarized spherical wave into x-polarized plane wave in reflection space simultaneously. Moreover, when y-polarized wave illuminates the MS in transmission space, the MS achieves scattering control on the y-polarized reflected wave to realize the diffuse scattering function. Exciting the MS with a horn antenna, the broadband antenna system with full-space function-integration and low backward RCS is realized. The antenna system achieves high-gain vortex wave radiation in transmission space, and high-gain beam frequency scanning in reflection space. Besides, when y-polarized wave illuminates the antenna array in transmission space, diffuse scattering stealth is achieved. Experimental results show that the 3 dB gain relative bandwidth of the vortex wave antenna in the transmission space is 67% (10∼20 GHz), the 3 dB gain relative bandwidth of the frequency scanning antenna in the reflection space is 54% (11.5∼20GHz), and the scanning angle covers 31°. The antenna backward RCS reduces more than 10dB between 11.7 GHz to 20 GHz.
A Low Profile, Broadband Circularly Polarized Beam Scanning Array
Authors: Zhao Ming-Yang , Lei Xue , Zhu Yi-Jun , Peng Qiang , Tang Zhao-ying , Fu Yi-yuan 
Published: June 2022

Abstract
Based on the idea of tightly coupled dipole array, a low profile, broadband circularly polarized array is designed in this paper. The circularly polarized phased array element consists of dual polarized dipoles with the same phase center and orthogonal arrangement, grounded coupling patches, resistive frequency selective surfaces (RFSS), and a 90° phase shifter network. In order to realize broadband scanning, the effect of RFSS on the input active voltage standing wave ratio and radiation axial ratio (AR) of the element is studied. The results show that the element can operate at 5-11.5GHz, within a ±45° angle scanning range, the AR of each scanning plane is less than 3dB, and the profile height is only 0.33 λ
high.
An Improved Method for Antenna and Probe Alignment in Auto-calibration of Millimeter-Wave Digital Monopulse Radar
Authors: Zheng Yu , Yao Chen , Zhao Guoqiang 
Published: June 2022

Abstract
Calibration is an effective method for improving digital monopulse radar tracking performance since it can eliminate the amplitude-phase imbalance between channels. Fast and accurate alignment between the antenna under test and the probe is an important part of the calibration. however, the narrow beam and high gain of a millimetre-wave band antenna pose a challenge to the alignment. To tackle this problem, we propose an improved alignment method based on the gradient feature of the radar radiation pattern. The method incorporates adaptive moment estimation to resist noise in the iteration process of the alignment. The high-accuracy alignment of the proposed method is verified by simulation and experiment. The root mean squared error of the alignment of the proposed method is 0.0046 degree in the absence of noise. At the SNR of 30 dB, the root mean squared error of the alignment is 0.008 degree. The proposed method improves the calibration efficiency and thus has a broad application prospect.
Research on Maximum Efficiency Output Control of Voltage Controlled Adjustable Constant Current Source
Authors: Yu Yingbo , Kang Zhongjian 
Published: June 2022

Abstract
Voltage controlled adjustable constant current source has simple structure and high output precision, but its high switching power consumption and low output power efficiency under current variation hinder the development of its high current application. A maximum efficiency output control method of constant current source based on small signal model is presented to reduce switching loss and achieve high efficiency output. A 0-4A adjustable constant current source prototype was built to verify the theory, and the experimental results show that when the setting current changes from 1 to 4A, the output dynamic response of the experimental group is rapid, the instantaneous peak power of MOS transistor is only 6.04w, and compared with the control group, the average efficiency of the system is from 85.85% up to 92.86%, which indicate a better power consumption control ability.
Design of a Novel Dual-band Dual-circularly Polarized Waveguide Slot Array Antenna
Authors: Tian Si-Yu , Lei Xue , Wang Hai , Zhao Ming-Yang , Gao Jun , Li Tian-Peng 
Published: June 2022

Abstract
A novel dual-band dual-circularly polarized waveguide slot array antenna is designed. The antenna opens two orthogonal slots with different lengths on the standard waveguide and is excited at two frequencies. The electric fields of TE10
and TE01
modes are obtained. To achieve the purpose of dual-band dual-circular polarization. Two orthogonal slots can not only make the antenna elements have slow-wave properties and delay phase, but also make the antenna elements in different frequency bands have the same virtual short-circuit wall, which simplifies the difficulty of design and processing. The antenna can achieve an equidistant array and become an array antenna. Through simulation verification, the S11<-10 dB in the two frequency bands from 11 GHz to 11.3 GHz and from 13.1 GHz to 13.8 GHz. In this bandwidth, the axial ratio bandwidth is less than 3 dB, respectively. The isolation between the two ends is better than 12 dB, and it has left and right circular polarization. The problem of the deterioration of the axial ratio of the circular polarization of the antenna caused by the different phases between the waveguide slot antennas is solved.
Research on the Propagation Characteristics of High Frequency Partial Discharge Signal in Transformer
Authors: Li Yang , Tang Zhiguo 
Published: June 2022

Abstract
In order to study the information contained in the high frequency partial discharge and the influence of transformer winding on the propagation of partial discharge signal, this paper injects high frequency small signals into the external leads, internal winding and enclosing screen of 110kV three-phase double-winding transformer to simulate the external discharge, inside and outside of the winding discharge to study the propagation characteristics of transformer partial discharge signal. The study shows that the partial discharge signal is coupled from one to others, and the signal can be detected at each detection end when partial discharge occurs; the partial discharge signal consists of high-frequency component and low-frequency component, the high-frequency component is mainly propagated through the capacitance between the windings, and the low-frequency component is mainly propagated through the windings; The polarity of the first wave of the time domain signal is different when the discharge of the internal winding of the transformer propagates to each detection point, the polarity of the first wave of the time domain signal is the same when the discharge of the outside winding propagates to each detection point. Among them, the discharge of the outside winding mainly propagates through the capacitor, and the low-frequency components of each detection terminal are seriously attenuated.
Design of an Aerospace Langmuir Probe Volt-ampere Characteristic Load Simulator
Authors: Zhao Zhendong , Wang Yi , Zhou Ying , Chen Guangfeng , Hu Xiangyu , Zhang Haiyan 
Published: June 2022

AbstractThe development process of space Langmuir probe needs to complete a large number of tests and calibration tests on the ground. Due to the long calibration period, complexity and high cost of plasma environment calibration, calibration tests are usually carried out after the instrument has been developed, in order to conduct preliminary tests on Langmuir probe during the instrument development process to verify the performance, as well as to save the cost of calibration tests and increase the reliability of the instrument, An advanced spatial Langmuir probe volt-ampere(I-V) load simulator was designed in this paper. Based on the positive and negative polarity of the external bias voltage, the I-V characteristic curve of the Langmuir probe was divided into positive and negative characteristic curves, which were realized by the combination of the output characteristic curves of NPN and PNP transistors, and the diode switching selectivity. The laboratory test results were consistent with the theoretical curve, verifying the validity and compliance of the design, which can play an important role in supporting the development of the space Langmuir probe and the calibration of the plasma environment.
Multi-sensor time synchronization algorithm based on Gaussian process regression
Authors: Yang Quan , Zhao XuanZhi , Zhang Wen , Jin WenJun 
Published: June 2022

Abstract
In order to address the problem of inconsistent sampling frequency and accuracy of each sensor in multi-sensor data fusion technology, the algorithm of Gaussian Process Regression (GPR) is proposed for time alignment, and in the scenario where the target motion model is uniform linear motion and uniform turning motion, the simulation is compared and analyzed respectively. The simulation results show that the proposed algorithm can effectively improve the accuracy of time synchronization.
Application of two spectrum refinement methods in frequency estimation
Authors: Deng Leilei , Leng Kaijing 
Published: June 2022

Abstract
Considering the limitation of FFT frequency estimation method in resolution, this paper briefly introduces the complex modulation ZOOM-FFT and Chirp-Z transform spectrum zooming methods. The simulation results show that the ZOOM-FFT method has better anti spectrum leakage and interference effect. Furthermore, the two methods are applied to the frequency estimation of underwater high-speed maneuvering target, and it is found that Chirp-Z transform method can obtain smoother and stable frequency history, and has more flexible frequency resolution.
Research on attitude control strategy of unmanned helicopter based on hybrid particle swarm optimization algorithm
Authors: Liu Zhiqiang , Ye Xi , Qian Tonghui , Yu Linwen 
Published: June 2022

Abstract
For the unmanned helicopter attitude control problem, an optimal control strategy based on hybrid particle swarm optimization (PSO) algorithm has been proposed. Firstly, a coupled dynamics model of the system has been established based on the structural characteristics of the unmanned helicopter system; secondly, a gain scheduling control method has been adopted to select multiple system stable operating points with real-time error as the scheduling variable, and a gain scheduling attitude controller has been designed; further, the inertia weights and learning factors are dynamically adjusted on the basis of the traditional PSO algorithm, and a hybrid PSO algorithm has been proposed for unmanned helicopter attitude control; finally, the improved controller has been compared and verified by the semi-physical. The experimental results show that the improved algorithm improves the attitude control effect and anti-interference capability of the unmanned helicopter, resulting in a reduction of the adjustment time by about 3.8s and the maximum steady-state amplitude by about 0.154°.