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2nd International Conference on Computer engineering and Application, ICCEA 2021

作者： Dong, Zeyu Lv, Fengrong Wan, Tao Jiang, Kaili Fang, Xueli Zhang, Lei University of Electronic Science and Technology of China School of Information and Communication Engineering Chengdu China Key Laboratory of Complex Aviation Simulation System Beijing China

ISBN: (纸本)9781665426169

Signal bispectral transformation can not only suppress the influence of Gaussian white noise on signal modulation recognition, but also retain the signal amplitude and phase information. It is also used to extract the non-linear characteristics. Compared with other high-order spectra, bispectrum has a simple processing flow. However, the direct use of all bispectrum as signal features will lead to two-dimensional template matching, causing lots of calculations. Converting two-dimensional bispectrum into one-dimensional sequence, for example, extracting slice information of bispectrum, or using integral bispectrum apparently reduce the amount of data to be processed while retaining part of the bispectrum information. We input the extracted bispectral transformation of radar signals into the neural network to realize modulation recognition. The simulations validate our conclusions that our proposed methods still have a high recognition probability while SNR is low. © 2021 IEEE.

关键词： Template matching

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Semi-supervised Open-set Recognition of Radar Active Jamming

Semi-supervised Open-set Recognition of Radar Active Jamming

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2021 CIE International Conference on Radar, Radar 2021

作者： Li, Hao Fang, Xueli Zhang, Lei Kang, Hui Zhang, Wei School of Information and Communication Engineering University of Electronic Science and Technology of China Chengdu China Key Laboratory of Complex Aviation Simulation System Beijing China

ISBN: (纸本)9781665498142

With the emergence of various kinds of complex radar jamming, radar jamming intelligent recognition technology has increasingly become the key to electronic counter-counter measures. To achieve radar jamming open-set recognition with a small number of tagged samples, Generative adversarial network-based pseudolabeled convolutional neural network (GAN-PL-CNN) model is proposed in this paper. Firstly, radar jamming is modelled, and the radar jamming datasets with known and unknown types are established after time-frequency transformation and image processing. Then, the adaptive pseudolabeling method is used to achieve semi-supervised recognition of radar jamming by combining the learning capability of convolutional neural networks and the characteristics of pseudolabeling to increase labeled samples intelligently. Finally, generative adversarial networks are introduced to enhance the recognition ability of the model and the discrimination ability of the unknown type through the game between the generator and the discriminator in the iterative process. Experimental results show that the GAN-PL-CNN model achieves 89.7%-95.1% for known types and 30.7%-86.8% for unknown types at 3%-6% labeling rate. As the number of labeled samples increases, the recognition effect becomes better and has a greater ability to exclude unknown type. © 2021 IEEE.

关键词： convolutional neural network open-set recognition pseudo-label Radar active jamming

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Radar Signal Detection Based on Ambiguity Function and Deep Learning 2

Radar Signal Detection Based on Ambiguity Function and Deep ...

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2nd International Conference on Computer engineering and Application, ICCEA 2021

作者： Lv, Fengrong Dong, Zeyu Wan, Tao Jiang, Kaili Fang, Xueli Zhang, Lei University of Electronic Science and Technology of China School of Information and Communication Engineering Chengdu China Key Laboratory of Complex Aviation Simulation System Beijing China

ISBN: (纸本)9781665426169

The ambiguity function describes the joint characteristics of the signal in the time domain and the frequency domain, and is usually used for signal recognition. The time domain and frequency domain distribution of noise is more spurious than the signal. Its ambiguity function can also reflect its characteristics. However, the direct use of the ambiguity function as the signal feature will increase the amount of calculation of the detection system, so slice it, which reduces the burden on the system for detecting signal information while preserving the information. At the same time, the radar signal detection based on neural network can avoid the influence of artificially setting the threshold on the detection performance of the system. So, we propose an algorithm for inputting the extracted fuzzy function slice sequence into a neural network to realize signal detection. simulation proves that when the signal-To-noise ratio of the received signal is very low, our proposed method still has a high detection probability. © 2021 IEEE.

关键词： Signal detection

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Self-precharge of floating capacitors in a five-level ANPC inverter

Self-precharge of floating capacitors in a five-level ANPC i...

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2012 IEEE 7th International Power Electronics and Motion Control Conference - ECCE Asia, IPEMC 2012

作者： Wang, Kui Li, Yongdong Zheng, Zedong Xu, Lie Ma, Hongwei State Key Laboratory of Control and Simulation of Power System and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing China

ISBN: (纸本)9781457720864

Five-level active neutral-point-clamped (ANPC) converter is a newly emerging topology which can overcome the drawbacks of traditional neutral-point-clamped and flying-capacitor multilevel converters. During the start-up of the converter, it must be ensured that the switches and capacitors cannot be overvoltage and overcurrent due to the uncharged floating capacitors. In this paper, a floating capacitor self-precharge method is proposed which, by transferring the circuit into a booster, charges the floating capacitors to the reference voltage with a very small average load current. simulation and experimental results are presented to verify the validity of this method. © 2012 IEEE.

关键词： Power converters

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Mechanism of contact electrification-induced microscale breakdown between separating electrodes

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Physical Review Applied 2025年第5期23卷 054059-054059页

作者： Jiandong Chen Yangyang Fu Department of Electrical Engineering Tsinghua University Beijing 100084 China State Key Laboratory of Power System Operation and Control Department of Electrical Engineering Tsinghua University Beijing 100084 China Sichuan Energy Internet Research Institute Tsinghua University Sichuan 610213 China

Since the 1990s, there has been a debate on whether the contact electrification (CE)-induced discharge mode is continuous or intermittent, and the understanding of the relationship between the electrode potential and Paschen’s curve remains controversial. In the present work, we demonstrate CE-induced microscale breakdown between two separating metal electrodes without an external voltage source and successfully reveal that continuous and intermittent discharge modes can both be realized by adjusting the electrode separation velocity. The CE-induced initial charge, electrode separation velocity, and breakdown time delay are identified as key factors, and their combined effects explicitly determine the breakdown mode. Further, it is found that in continuous breakdown mode with a sufficiently high initial charge, the electrode potential versus gap distance exactly follows the modified Paschen’s curve, which incorporates the field emission regime. This discovery suggests that a microscale breakdown curve can be determined based on a single characterization of the separating electrode potential without the need to perform redundant repeated experiments. The results of this study elucidate microscale breakdown physics with moving electrodes and inform better control and optimization of microelectromechanical devices for applications including energy harvesters, microsensors, and detectors.

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Design and implementation of photovoltaic lighting system with high luminous efficacy LEDs

Design and implementation of photovoltaic lighting system wi...

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2012 IEEE 7th International Power Electronics and Motion Control Conference - ECCE Asia, IPEMC 2012

作者： Yuan, Liqiang Chen, Zhiping Hu, Xianlai Ge, Junjie Zhao, Zhengming State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing China

ISBN: (纸本)9781457720864

With the background park lighting application, and based on the characteristics of advanced devices in the system, this paper studies the photovoltaic (PV) light emitted diode (LED) lighting system in three main aspects, which are the design of the whole system, hybrid control strategy combining the maximum power point tracing (MPPT, for PV panels) with the energy management(for battery), and LED driving and dimming. Taking the example of an actual 50W high luminous efficacy LED system, the design, implantation and experiments are described in detail. In addition, the long-term measurement results in real environment are illustrated in this paper. © 2012 IEEE.

关键词： Solar panels

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Reducing the impact of source internal resistance by source coil in resonant wireless power transfer

Reducing the impact of source internal resistance by source ...

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作者： Zhang, Yiming Lu, Ting Zhao, Zhengming State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing China

ISBN: (纸本)9781479956982

Wireless power transfer (WPT) is the state-of-the-art research interest. In the WPT system efficiency is an important figure of merit. In order to reduce the impact of the source internal resistance and improve the system efficiency of the conventional two-coil structure, a source coil is added to the two-coil structure, forming a three-coil structure. Both the two-coil structure and the three-coil structure are modeled and analyzed with the circuit theory. The system efficiencies of both structures with optimal loads and a fixed load are deduced. The system efficiency of the three-coil structure is proved to be higher than that of the two-coil structure. An experimental apparatus is implemented and the experimental results match well with the theoretical calculations. The larger the source internal resistance, the more significantly the addition of the source coil improves the system efficiency. © 2014 IEEE.

关键词： Energy transfer

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Travelling wave differential protection based on equivalent travelling wave 13

Travelling wave differential protection based on equivalent ...

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13th International Conference on Development in Power system Protection 2016, DPSP 2016

作者： Tang, Lanxi Dong, Xinzhou Shi, Shenxing Wang, Bin State Key Laboratory of Control and Simulation of Power System and Generation Equipments Dept of Electrical Engineering Tsinghua University Beijing China

ISBN: (纸本)9781785618260

Travelling wave (TW) differential protection fully utilizes the fault information contained in TW at both terminals of a transmission line, so it's a protection with high reliability and high selectivity. However, because TW differential protection needs a large amount of communication, it cannot be put into practical use. This paper proposes a TW differential protection which is based on equivalent travelling wave (ETW). Fault information is not lost during the process of getting ETW, so the proposed protection has the same reliability and selectivity with traditional TW differential protection. Because only several modulus maxima are needed to be sent to the opposite terminal, the traffic is largely reduced and the protection can operate much more rapidly. Extensive simulations validate the proposed protection.

关键词： Wavelet transforms

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Adaptive deblock for DC line fault in full bridge sub-module based MMC-HVDC system 15

Adaptive deblock for DC line fault in full bridge sub-module...

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15th International Conference on Developments in Power system Protection, DPSP 2020

作者： Cai, Jing Dong, Xinzhou State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing China

ISBN: (纸本)9781713827894

Modular multilevel converter based high voltage direct current (MMC-HVDC) transmission technology has been widely applied in power systems, such as AC systems interconnection and renewable energy access, due to its superiorities. The long distance and complex operation environment lead to high probability of DC transmission line faults. Inevitable faults will interrupt normal power transmission and may cause severe accidents without appropriate faults handling scheme in both HVDC and AC/DC hybrid systems. MMC-HVDC utilizing submodules with fault clearing ability, such as Full-Bridge-Submodule (FBSM), can reduce fault current rapidly through blocking all submodules and attempt to resume power transmission by deblocking after waiting for deionization time. But the deblock operation is blind, which may aggravate outrage consequences with producing extra impacts on system and extending fault handling time in case of permanent faults. In order to realize ideal fault handling, which means submodules only deblock under temporary fault while cut off the fault line in case of permanent fault, an adaptive deblock strategy is proposed in FBSM based MMC-HVDC system mainly through distinguishing two fault states. A simulation model is established in PSCAD/EMTDC to verify feasibility and effectiveness of proposed scheme. Applicability to other submodules with fault clearing capability also been analysed. © 2020 IET Conference Publications.

关键词： Renewable energy resources

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Design and implementation of the compact main circuit of IGBT-based converter

Design and implementation of the compact main circuit of IGB...

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2008 IEEE Vehicle Power and Propulsion Conference, VPPC 2008

作者： Wang, Xuesong Zhao, Zhengming Yuan, Liqiang Zhang, Yingchao State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing China

ISBN: (纸本)9781424418497

The compact main circuit has many advantages, such as reducing volume and weight, saving costs and convenient for transportation. This paper presents three key problems including switching power supply, sampling and protection system, and cooling system. Through simplifying circuit and optimizing device parameters, the switching power supply can provide multiplex regulated power supplies with 540 VDC input directly. A simple circuit based on ripple principle can detect missing phase of input fault easily. The heat sink can be designed in a small volume through selecting suitable cooling fans, reducing switching frequency and setting minimum pulse width. A 15kW converter has been designed and implemented based on the above. Furthermore, this main circuit has been proved by practical application and long-term reliable operation. © 2008 IEEE.

关键词： Cooling systems

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