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4th IEEE China International Electrical and Energy Conference, CIEEC 2021

作者： Xiong, Qiaopo Liu, Hengyang Rao, Sitao Luo, Zhiqing Tu, Junyao Kong, Wubin Duan, Xunyu Li, Zhike Zhong, Zhixian Wmcri Cssc Laboratory of Low-Frequency Electromagnetic Communication Technology Hubei China

ISBN: (纸本)9781728171494

The crosstalk voltage is the result of the combined effect of the displacement current generated by the gate-drain capacitance and the induced voltage introduced by the common source inductance. When considering common-source inductance, the relationship between the driving circuit impedance and the spikes of crosstalk voltage is no longer a single correlation. This paper starts with the crosstalk phenomenon in the double pulse test (DPT) circuit, introduces the causes of the crosstalk phenomenon in detail, and constructs the equivalent circuit of the drive loop to obtain the mathematical expression of the crosstalk voltage calculation. Finally, through mathematical analysis, the influence of gate-source capacitance and gate resistance on the spikes of crosstalk voltage is obtained, which provides guidance for the design of driving parameters. © 2021 IEEE.

关键词： Crosstalk

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Research on Loran-C Transmitting System technology Based on Class-D Power Amplifier

Research on Loran-C Transmitting System Technology Based on ...

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2024 IEEE China International Youth Conference on Electrical Engineering, CIYCEE 2024

作者： Wu, Bin Zha, Ming Zhao, Jinbo Luo, Cheng 722 Research Institute Cssc Hubei Provincial Key Laboratory for Low-Frequency Electromagnetic Communication Technology Wuhan430074 China

ISBN: (纸本)9798331530174

The Objective of this study is to study a new all-solid-state Loran-C transmission technology based on Class-D power amplifiers, and to apply the research results to the 'blind compensation' or 'enhancement' of the positioning, navigation and timing (PNT) functions of the transmission system, as well as to guide the construction of large-scale transmission stations. The standard Loran-C waveform was theoretically analyzed, modeled and simulated, and the discrete excitation signal for three time periods was generated by pre-distortion modulation technology, and the trapezoidal voltage waveform was superimposed and synthesized by driving the Class-D power amplifiers module to load the antenna tuning network, and finally the standard Loran-C current waveform was formed on the antenna. The results solve the defects of the complex composition of the transmitter of the semi-circular magnetic pulse generator and the high dependence on hardware parameters for the waveform generation method, which makes it difficult to quickly adapt to different transmitting antennas and new systems, improve the transmission efficiency and reduce the operating cost. The Loran-C transmission technology based on Class-D power amplifiers improves the performance of the system from the aspects of new system waveform research, machine efficiency, waveform adaptability and maneuverability, which meets the requirements of the development of a new generation of long-wave navigation timing transmission system in China, and the technology has high military and social application value. © 2024 IEEE.

关键词： Pulse generators

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Investigation of the Vibration Behavior of a Foil Thrust Bearing Housing Under Angular Disturbance of the Runner 2nd

Investigation of the Vibration Behavior of a Foil Thrust Bea...

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2nd International Conference of Mechanical System Dynamics, ICMSD 2023

作者： Chen, Rui Zhang, Chuanbing Cheng, Yongjun Wang, Bi Wang, Zixi State Key Laboratory of Tribology Tsinghua University Beijing China State Key Laboratory of High-End Compressor and System Technology Hefei China Laboratoy of Low Frequency Electromagnetic Communication Technology With the WMCRT CSSC Wuhan China

ISBN: (纸本)9789819980475

Foil thrust bearings are widely used in high-speed rotating machinery due to their temperature tolerance and contamination-free operation. However, the gas film thickness of the bearing can be weakened by the runner’s runout, which reduces the maximum load capacity of the bearing. To improve the load-carrying capacity of the bearing under runner’s runout, the angular stiffness and damping of the foil thrust bearing housing can be changed to provide angular tracking ability. However, this can result in resonance, which is detrimental to system stability and load-carrying capacity improvement. In this paper, the angular resonance behavior of the bearing housing was investigated theoretically. The results indicate that when the rotor speed is close to the critical speed, the bearing housing experiences angular resonance characterized by a sharp increase in motion amplitude and a sudden phase shift, leading to poor angular tracking ability. By adjusting the critical speed through changes in the angular stiffness, angular damping, and transverse moment of inertia, the angular resonance can be avoided for the bearing system. The results show that there is an optimal angular stiffness for the bearing housing that enables it to have maximum load. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.

关键词： Stiffness

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A Joint Phase and Timing Estimation Algorithm for MSK Signals Based on Walsh sequence 3

A Joint Phase and Timing Estimation Algorithm for MSK Signal...

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3rd IEEE International Conference on communications, Information System and Computer Engineering, CISCE 2021

作者： Liu, Yong Hu, Gang Huang, Linmin Xie, Mingming Laboratory of Low Frequency Electromagnetic Communication Technology with the Wmcri Cssc Wuhan China College of Information and Communication Engineering Harbin Engineering University Harbin China

ISBN: (纸本)9780738112152

MSK signal is a special continuous phase modulation signal with continuous phase and constant envelope. It is very suitable for transmission in narrowband channels and is widely used in satellite communications and wireless mobile communications. However, the existing MSK phase and timing estimation algorithms have low estimation accuracy and high implementation complexity in the case of low signal-to-noise ratio (SNR). On the basis of data-aided, this paper proposes a joint phase and timing estimation algorithm based on Walsh sequence. The algorithm uses Walsh sequence as training sequence, and uses the orthogonality of Walsh sequence and the orthogonal decomposition expression of MSK signal to realize the parallel independent estimation of phase and timing offset. The simulation results show that under certain phase and timing offset conditions, the joint algorithm can effectively estimate the phase and timing offset, and at the cost of a lower system bandwidth, obtain approximately ideal system performance. © 2021 IEEE.

关键词： Timing circuits

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Influence of Corona Space Charge on Subsequent Streamer Inception from Horizontal Conductors during Lightning Attachment Process

Influence of Corona Space Charge on Subsequent Streamer Ince...

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2021 International Conference on Advanced Electrical Equipment and Reliable Operation, AEERO 2021

作者： Xiong, Qiaobo Wang, Yawei Liu, Qing Xiang, Chunqing Xia, Dezhi Laboratory of Low Frequency Electromagnetic Communication Technology with the 722 Research Institute CSSC Wuhan China Huazhong University of Science and Technology State Key Laboratory of Advanced Electromagnetic Engineering and Technology Wuhan China

ISBN: (纸本)9781665402644

the space charge generate by the corona discharge near the UHVDC overhead transmission lines can distort the electric field distribution under thunderstorms. this paper presents a numerical model to estimate the corona space charge produced by horizontal conductors in response the electric field generated by both thundercloud and downward leader. Secondly, the corona space charge development process from ground conductors was obtained. The transition process of corona discharge to subsequent streamer is analyzed. the inhibition effect of the space charge layer on the subsequent streamer initiation was calculated by considering different conductor diameters. It is concluded that there is an optimal diameter for horizontal conductors which can ensure a superior capability to launch subsequent streamers, which should achieve a corona-free condition under the electric field of thundercloud. © 2021 IEEE.

关键词： Electric space charge

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Conducted EMI Model and Coupling Resonant Mechanism Analysis of Multi-Cell Converter System 10

Conducted EMI Model and Coupling Resonant Mechanism Analysis...

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10th IEEE International Power Electronics and Motion Control Conference, IPEMC 2024 ECCE Asia

作者： Qing, Zhuo Guo, Peng Xu, Qianming Hu, Jiayu Jia, Yingzhe Chen, Penghui Zhou, Ziyan Li, Yuze Xiong, Qiaopo Hunan University State Key Laboratory of High-Efficiency and High-Quality Conversion for Electric Power Changsha410082 China Cssc Laboratory of Low-Frequency Electromagnetic Communication Technology with the Wmcri Wuhan430079 China

ISBN: (纸本)9798350351330

Multi-cell converter is used to improve the current capability and power rating of a power supply system. Due to the faster switching speeds and higher power ratings, wide-bandgap (WBG) power semiconductor devices are used for enhancing the efficiency and power density of converters, which also result in severe electromagnetic interference (EMI) because of the large dv/dt and di/dt slew rates during switching transients. Furthermore, the coupling effect in multi-cell converter aggravates EMI emissions. In this paper, the common-mode (CM) model of a multi-cell converter system is derived. Then, the transfer admittance is analyzed, revealing that the conduction paths among cells form a resonance peak, the frequency of which is related to the number of cells and filter parameters. Finally, the correctness of the theoretical analysis is verified by simulation results. © 2024 IEEE.

关键词： Signal interference

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Portable underwater audio communication system based on blue LEDs 14

Portable underwater audio communication system based on blue...

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14th International Photonics and Optoelectronics Meetings, POEM 2022

作者： Han, Shunfeng Li, Jia Ding, Zhongyi Jiang, Yan Gao, Xumin Wang, Yongjin Laboratory of Low Frequency Electromagnetic Communication Technology with the 722 Research Institute CSSC Wuhan China GaN Optoelectronic Integration International Cooperation Joint Laboratory of Jiangsu Province Nanjing University of Posts and Telecommunications China

ISBN: (纸本)9781510664050

With the expansion of human activities underwater, such as environmental monitoring, underwater exploration, and scientific data collection, there is an urgent need for a secure, reliable, and high-speed underwater wireless communication technology. Visible light communication technology, as a necessary path for future 6G high-speed wireless communication, has the advantages of high bandwidth, high confidentiality, lightweight equipment size, as well as meets the concept of carbon neutrality. With the rapid development of LED industry, LED-based visible light communication technology has also been widely used and developed, only that most of the researches are established under short distance and high-speed laboratory conditions. In view of the integration requirements of lighting and communication, as well as the serious attenuation of radio frequency communication in water that causes the limited transmission distance, and the low bandwidth of underwater acoustic communication, this paper demonstrates underwater audio transmission over 10 m distance, exploiting four blue (454 nm) LEDs at the transmitter and a photodiode at the receiver. The system uses STC15W4K60S4 microcontroller as the main control chip. The transmitter conducts low-pass filtering and signal amplification through MAX9813L and AD828, and drives LEDs to realize the conversion and transmission of electro-optic signals. The receiver uses photodiode to convert the received optical signal into an electrical signal, and generates the output signal of the audio playback device through transimpedance amplification and filter circuits. Underwater test results prove that the proposed communication system can achieve high audio transmission quality. © 2023 SPIE.

关键词： Visible light communication

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Mechanism of Seebeck coefficient variation at the output of NiCr/NiSi thin film thermocouple with different wires 3

Mechanism of Seebeck coefficient variation at the output of ...

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2023 3rd International Conference on Measurement Control and Instrumentation, MCAI 2023

作者： Liu, Zhihui Guo, Tengda Cheng, Yongjun Wang, Bi Shen, Kai Hu, Kai Zhou, Jiankang Zhang, Chuanbing Wang, Zixi Ding, Wanyu State Key Laboratory of Tribology in Advanced Equipment Tsinghua University Beijing100084 China College of Materials Science and Engineering Dalian Jiaotong University Dalian116028 China Laboratory of Low Frequency Electromagnetic Communication Technology Wmcrt Cssc China State Key Laboratory of High-end Compressor and System Technology Hefei Anhui230031 China

In this paper, by using magnetron sputtering to prepare NiCr/NiSi thin film thermocouples, the static calibration method is used for NiCr/NiSi thermocouples with rapid temperature calibration experiments. Different temperature calibration curves are obtained. The Seebeck coefficient of NiCr/NiSi thin film thermocouples connected to NiCr/NiSi wires is significantly higher (41.39 μV/°C) than that of NiCr/NiSi wires (0 μV/°C). The Seebeck coefficient (41.39 μV/°C) of the NiCr/NiSi thin-film thermocouple connected to copper wire is significantly higher than that of the thermocouple connected to copper wire (0 μV/°C). The problem of the Seebeck coefficient of the K-type thermocouple is analyzed by experimental data, which provides the relevant parameter basis for the use of the K-type thermocouple. The method has the advantages of simple equipment, convenient operation, accurate and reliable data, and provides a basis for the sensor to measure the temperature measurement. © Published under licence by IOP Publishing Ltd.

关键词： Temperature measurement

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Online Observation for IGBT Module Loss and Spatial Temperature with Aging Tracking: A Data-driven Method 14

Online Observation for IGBT Module Loss and Spatial Temperat...

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14th IEEE International Symposium on Power Electronics for Distributed Generation Systems, PEDG 2023

作者： Liang, Fengrui Wang, Yu Wei, Jinxiao Feng, Hao Ran, Li Chongqing University State Key Laboratory of Power Transmission Equipment and System Security and New Technology Chongqing China Cssc Laboratory of Low Frequency Electromagnetic Communication Technology with the Wmcri Wuhan China University of Warwick Coventry School of Engineering United Kingdom

ISBN: (纸本)9798350328233

The loss and heat flux of IGBT module change with package degradation, resulting in the variation of case temperature and its distribution. Inspired by the aging mechanism of module, this study performs an online observation for IGBT's time-varying profile by collecting temperature of multiple points in the bottom case, which achieves a spatial temperature reconstruction beyond junction temperature with aging track capability. Moreover, the loss can also be obtained by the thermal performance at steady state. A deep neural network (DNN) based data-driven model is established by collecting data in varied degradation level and operating condition, which favors the online observation by its low computation cost. A dedicated optical fiber positioning is proposed to facilitate temperature acquisition, and the process of data-driven modeling is illustrated in detail. Results show that the spatial temperature inside the module and the power loss can be accurately reconstructed within 5% error, and the module degradation status are well tracked. © 2023 IEEE.

关键词： Deep neural networks

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Reliability-Oriented Design of DC-Link Considering the Second-Order Harmonic Current Routing in an SST Cell

CPSS Transactions on Power Electronics and Applications

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CPSS Transactions on Power Electronics and Applications 2023年第3期8卷 290-299页

作者： Wei, Jinxiao Wang, Yawei Liu, Sicong Feng, Hao Ran, Li CSSC Laboratory of Low Frequency Electromagnetic Communication Technology with the WMCRI Wuhan430000 China State Grid Corporation of China Chengdu610005 China School of Engineering University of Warwick CoventryCV4 7AL United Kingdom Chongqing University State Key Laboratory of Power Transmission Equipment and System Security and New Technology Chongqing400044 China

Second-order harmonic current (SHC) inevitably presents in the two-stage AC/DC and DC/DC system, e.g., solid-state transformer (SST) cell. Unregulated harmonics routing leads to reliability defects, which may appear in DC-link and DC/DC stage. This manuscript presents a reliability-oriented design method via routing the SHC. Firstly, the SHC distribution in the two-stage SST cell is modeled, and their effects on the reliability of DC-link capacitor and DC/DC stage are revealed. Interactions are highlighted between the reliability of DC-link and DC/DC stage. It illustrates that a small capacitance may favor the DC-link reliability, yet jeopardizing the overall system. A tradeoff analysis is performed to achieve longer mean time to failure (MTTF) on an SST cell level. The harmonic distribution unravels a new mechanism that governs the reliability balance between critical components. It also provides an alternative perspective to the reliability-oriented design. The distribution model and design framework are performed in a 15 kW SST cell. © 2017 CPSS.

关键词： Reliability

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