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11th Frontier Academic Forum of Electrical engineering, FAFEE 2024

作者： Zhang, Yuhuan Liu, Mi Guo, Chuanwei Ma, Tao zhao, Chuang Li, Xinxin Chen, Yonggang Li, Yan Beijing Spacecrafts Beijing100094 China Beijing Space Power Conversion and Control Engineering and Technology Research Center Beijing100094 China

ISBN: (纸本)9789819788316

Deep space exploration is an important field of space exploration and astronautical activities in today's world, which is of great significance to the development of human civilization. Aerospace power supply system is an important part of the power supply system for deep space exploration, so research on its low-temperature pull and deflection characteristics is particularly important. In this paper, the low-temperature pull-off characteristics of the Aerospace power Supply are verified and enhanced. Firstly, the application circuit of VDMOS, which is the core component of aerospace power supply, is analyzed, and two different working modes, namely, single switching application and high frequency switching application, are summarized. Secondly, the low-temperature pull-off test of aerospace power supply is carried out to compare and analyze with the normal temperature pull-off test to identify the reasons for poor low-temperature pull-off characteristics.. Finally, the low-temperature pull-off control link is analyzed, and the solution is given and verified through the test, which improves the low-temperature pull-off characteristics of the astronautical power supply, and contributes to the development of high reliability of the power supply system for deep space exploration. © beijing Paike Culture Commu. Co., Ltd. 2025.

关键词： space research

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Construction of Grid-Based Virtual Synchronous Mechanism and Voltage Feedforward control Method Under Weak Grid 11th

Construction of Grid-Based Virtual Synchronous Mechanism and...

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11th Frontier Academic Forum of Electrical engineering, FAFEE 2024

作者： Xu, Jiacheng Chen, Yandong Xie, Zhiwei Li, Xuyang Zhao, Chen National Electric Power Conversion and Control Engineering Technology Research Center Hunan University Changsha410082 China

ISBN: (纸本)9789819788194

In order to solve the problem that the traditional Grid-Following (GFL) grid-connected inverter is prone to oscillation and instability under weak grid, a grid-following virtual synchronous mechanism construction and voltage feedforward control method based on the swing equation of the synchronizer are proposed. Firstly, the method refers to the Virtual Synchronous Generators (VSG) technology to derive and reconstruct the swing equation of the synchronous machine, and proposes a new voltage feedforward controller, which introduces inertia and damping to the control of the GFL inverter and improves the stability of the GFL inverter under the weak power grid. Then, the proposed control method is theoretically analyzed and optimized by establishing the frequency-coupling sequence admittance model, and the results show that the proposed method can significantly improve the negative resistance characteristics of the inverter in the middle and low frequency bands to enhance the stability of the GFL grid-connected inverter under the weak grid. Finally, this paper verifies that the proposed control method can operate stably in weak and very weak grids, as well as in strong power grids, which is of great significance for improving the adaptability and reliability of GFL grid-connected inverters in complex grid conditions. © beijing Paike Culture Commu. Co., Ltd. 2025.

关键词： Feedforward control

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Anti-Offset Wireless power Transfer System Based on Variable Inductor 11th

Anti-Offset Wireless Power Transfer System Based on Variable...

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11th Frontier Academic Forum of Electrical engineering, FAFEE 2024

作者： Qu, Sizhuo Chen, Yandong Luo, Cong Xie, Jiawei Wu, Longbang National Electric Power Conversion and Control Engineering Technology Research Center Hunan University Changsha410082 China

ISBN: (纸本)9789819788194

In recent years, wireless power transfer has been widely studied for its advantages of safety, convenience and intelligence. However, in the actual working scene, the horizontal or vertical offset of the receiving coil may cause a large fluctuation in the output voltage of the system, which seriously affects the life of the load, and the surge of the primary side current leads to the heating of the switch and even the overcurrent of the device. Therefore, this paper proposes an anti-offset control strategy based on adjusting the variable inductor to compensate for the surge of the primary side current and the fluctuation of the output voltage caused by the coil offset. In this paper, a detuned series-series anti-offset wireless power transfer system with variable inductor added to the secondary side is designed. The variable inductor is adjusted by changing the permeability of the variable inductor. Based on the adjustment of the variable inductor, the output voltage is constant when the coil is offset and the primary side current is reduced. The control strategy does not require wireless communication. Finally, a 600 W wireless power transfer system with stable output voltage of 72 V is built. The experimental results show that the tolerance range of the system in the horizontal direction is 0–12 cm, and the tolerance range in the vertical direction is 5–11 cm, and the current of the transmitting coil is reduced when the coil is offset. The system improves the freedom and stability of the wireless power transfer system. © beijing Paike Culture Commu. Co., Ltd. 2025.

关键词： Inductive power transmission

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Reliability analysis for a dynamic k-out-of-n system with thermal balance control

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Reliability engineering and System Safety 2025年 262卷

作者： Xu, Dong Tian, Yubin Wang, Dianpeng Shi, Junbiao School of Mathematics and Statistics and Key Laboratory of Mathematical Theory and Computation in Information Security Beijing Institute of Technology Beijing100081 China Faculty of Computational Mathematics and Cybernetics Shenzhen MSU-BIT University Shenzhen518172 China Beijing Spacecraft Corporation and Beijing Space Power Control Engineering Conversion Research Center Beijing100094 China

Thermal failures, often caused by localized high temperatures, are a pervasive and critical issue in system operations, significantly impacting reliability and performance. Optimizing the connection locations in dynamic systems presents a promising and effective measure to mitigate these failures. By strategically managing the spatial distribution of heat, it is possible to reduce localized high temperatures and enhance overall system reliability. However, this approach has been largely overlooked in existing research, leaving a gap in addressing thermal imbalance effectively. This study proposes a novel balance measure to quantify thermal balance. Compared to existing balancing systems, this is the first time that the spatial uniformity of performance distribution is considered. The balance measure can help the system maintain thermal balance while meeting dynamic demands, thereby reducing thermal failures and improving system reliability. In addition, the thermal balance was incorporated for the first time in studies of dynamic k-out-of-n models with a failure threshold modeled by a random process. To address the system's complexity, we develop a reliability assessment method based on Monte Carlo simulation and solve a redundancy allocation problem to minimize system volume while meeting reliability constraints. Numerical examples demonstrate the effectiveness of our approach, showcasing its practical applicability and impact. © 2025

关键词： Time-to-failure

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Resource Allocation for Emergency Communications in Distribution Network Satellite Communication System

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China Communications 2025年第2期22卷 95-111页

作者： Xie Haoran Zhan Yafeng Fang Xin Department of Electronic Engineering Tsinghua UniversityBeijing 100084China Beijing National Research Center for Information Science and Technology Tsinghua UniversityBeijing 100084China State Key Laboratory of Space Network and Communications Tsinghua UniversityBeijing 100084China State Grid Jiangsu Electric Power Co. Ltd.Research InstituteNanjing 210000Jiangsu ProvinceChina

Frequent extreme disasters have led to frequent large-scale power outages in recent *** quickly restore power,it is necessary to understand the damage information of the distribution network ***,the public network communication system is easily damaged after disasters,causing the operation center to lose control of the distribution *** this paper,we considered using satellites to transmit the distribution network data and focus on the resource scheduling problem of the satellite emergency communication system for the distribution ***,this paper first formulates the satellite beam-pointing problem and the accesschannel joint resource allocation ***,this paper proposes the Priority-based Beam-pointing and Access-Channel joint optimization algorithm(PBAC),which uses convex optimization theory to solve the satellite beam pointing problem,and adopts the block coordinate descent method,Lagrangian dual method,and a greedy algorithm to solve the access-channel joint resource allocation problem,thereby obtaining the optimal resource scheduling scheme for the satellite ***,this paper conducts comparative experiments with existing methods to verify the effec-tiveness of the proposed *** results show that the total weighted transmitted data of the proposed algorithm is increased by about 19.29∼26.29%compared with other algorithms.

关键词： distribution network emergency communication resource scheduling satellite communication

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A Quasi-Parallel Resonant Switched Capacitor DC-DC Converter with Wide Input Voltage Range Regulation and Enhanced Dynamic Performances

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IEEE Journal of Emerging and Selected Topics in power Electronics 2025年

作者： Qi, Jingjing Wu, Xuezhi Sun, Kai Tsinghua University State Key Laboratory of Power System Operation and Control Department of Electrical Engineering Beijing100084 China Beijing Jiaotong University National Active Distribution Network Technology Research Center Beijing100044 China

Wide-range and high-efficiency DC-DC converters are in high demand for various applications, such as distributed systems, electric vehicles, and DC buildings. Resonant switched capacitor converters (ReSCC) can achieve soft switching, have small passive device capacity, and exhibit low voltage stress, but the voltage ratio is difficult to be regulated continuously. In this paper, a quasi-parallel resonant switched capacitor DC-DC converter is proposed to satisfy the design requirements, which incorporates a ReSCC with soft-switching and variable voltage ratio, as well as a Buck converter. In addition, a simplified optimal trajectory controller for ReSCC is investigated, which can be combined with PI controller of Buck converter to enhance the load transient of the proposed converter. Moreover, the input voltage feedforward control is implemented with the optimized feedforward coefficient to suppress the input voltage disturbance. The proposed converter can achieve high efficiency and rapid dynamic response over a wide conversion range. The correctness of the theoretical analyses is verified by a 36V∼60V-5V/20A prototype. © 2013 IEEE.

关键词： Capacitor bank

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Numerical analysis and performance investigation of holographic spectrum-splitting concentrated photovoltaic-thermoelectric hybrid system with phase change material

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Energy conversion and Management 2025年 328卷

作者： Hu, Yue Li, Piaopiao Yao, Yucheng Lv, Hui Xu, Cheng School of Science and Hubei Engineering Technology Research Center of Energy Photoelectric Device and System Hubei University of Technology Wuhan430068 China Key Laboratory of Power Station Energy Transfer Conversion and System of Ministry of Education North China Electric Power University Beijing102206 China

To address the fluctuating nature of solar energy and achieve full spectrum utilization, a novel holographic spectrum-splitting concentration photovoltaic-thermoelectric hybrid system with phase change material is proposed in this study. Specifically, a two-layer volume holographic grating splitter is designed to separate the targeted spectrum from incident solar radiation for three spatially separated photovoltaic cells, while the thermoelectric module is employed to recover the residual heat from photovoltaic cells for electricity generation subsequently. Then, a heat storage layer with paraffin is positioned between the photovoltaic cells and the thermoelectric module to stabilize the temperature fluctuation and prolong the operation time for thermoelectric module. Thus, the conversion efficiency of solar to power can be significantly enhanced and a stable power supply is achieved by the proposed system. A thermodynamic mathematic model is established in this study, and the energy, exergy, and economic analysis are conducted comprehensively. The results show that under optimum conditions, the total energy and exergy efficiency of the proposed system reaches 30.2 % and 32.4 %, respectively. Among all components, the heat sink for thermoelectric module is the most inefficient component and highest exergy destruction is observed in the photovoltaic cells. © 2025 Elsevier Ltd

关键词： Exergy

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Techno-economic evaluation on a new integration of air-cooled coal-fired power plant and dual-pressure organic Rankine cycle for cold-side waste heat recovery

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Energy 2025年 327卷

作者： Hao, Ruijun Hao, Yongsheng Zhang, Junli Zhang, Hongsheng National Engineering Research Center of Power Generation Control and Safety School of Energy and Environment Southeast University Nanjing210096 China College of Mechanical and Electrical Engineering Beijing University of Chemical Technology Beijing100029 China

To boost coal-fired plants energy efficiency for load-regulation demands. an integration scheme (CPG-DPORC) is proposed wherein multiple extraction steams of different grades from the air-cooled coal-fired power generation system (CPG) drive the dual-pressure organic Rankine cycle (DPORC) step-by-step in a relay way. This scheme combines the high thermo-power conversion of the organic Rankine cycle for low- and medium-grade heat sources and the steam Rankine cycle for high-grade ones. It also flexibly matches CPG and DPORC heat sources, enabling deeper steam energy segmentation. Through such modifications, this approach achieves multiple goals: enhancing power output, recovering exhaust heat, and preventing air-cooling system freezing. A techno-economic evaluation of a 600 MW CPG system showed the retrofit significantly increased output power. Notably, the CPG-DPORC system shows directionally opposite performance advantages over the integrated simple organic Rankine cycle system (CPG-SORC). When the heat distribution ratio reaches 1 at 100 % THA, compared to the original CPG system and CPG-SORC system, the CPG-DPORC system, improves energy efficiency by 0.89 % and 0.17 %, improves exergy efficiency by 0.87 % and 0.17 %, and reduces the standard coal consumption rate by 6.59g/kWh and 1.23g/kWh. Economic evaluations further demonstrate that the initial total investment cost increases by 13.34 × 106USD and 0.57 × 106USD, the levelized cost of electricity (LCOE) reduces by 0.90 USD/MWh and 0.24 USD/MWh and the dynamic payback period (DPP) is shortened by 0.36 years and 0.10 years. Environmental evaluations show that the CO2 emission decrement increases by 66,841.84 tons/year and 12,739.54 tons/year. This integration promotes the shift to a renewable-dominated energy structure. © 2025 Elsevier Ltd

关键词： Waste heat utilization

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A method for battery health estimation under variable operating conditions based on the fusion of simplified electrochemical model and alpha evolution-back propagation model

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Journal of Energy Storage 2025年 123卷

作者： Shan, Runzhe Wang, Yaxuan Wang, Chao Cui, Yue Guo, Shilong Jiang, Yunfeng Wang, Qiwei Zhao, Lei Rong, Changru Li, Junfu Wang, Zhenbo State Key Laboratory of Space Power-Sources MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage MOE Engineering Research Center for Electrochemical Energy Storage and Carbon Neutrality in Cold Regions School of Chemistry and Chemical Engineering Harbin Institute of Technology Heilongjiang Harbin150001 China School of Automotive Engineering Harbin Institute of Technology at Weihai Shandong Weihai264209 China National Key Laboratory of Advanced Vehicle Integration and Control China FAW Grp Co Ltd Jilin Changchun130013 China

In recent years, research on the state of health (SOH) estimation of lithium-ion batteries under variable operating conditions receives widespread attention. Data-driven methods for SOH estimation of lithium-ion batteries often lack interpretability and reliability. This study proposes a novel model-data hybrid-driven approach that combines a simplified electrochemical model with an α-evolution-back propagation model to accurately predict SOH under variable operating conditions. The exponential-trigonometric optimization algorithm is applied for the first time to effectively identify parameters of the simplified electrochemical model, extracting more reliable and interpretable features throughout the full lifecycle of lithium-ion batteries. The alpha evolution algorithm is employed to optimize the initial parameters of the back propagation neural network, using features based on model parameters identified under variable operating conditions as inputs to the alpha evolution-back propagation model for SOH estimation. The proposed method is validated on three self-constructed datasets under variable operating conditions. The results show that the prediction accuracy exceeds 99.5 %, with the highest accuracy approaching 99.9 %. The training and testing dataset partitioning criteria used in this study hold significant practical relevance, aligning well with the requirements of using historical data to predict SOH degradation of retired lithium-ion batteries under predefined scenarios for their cascade utilization. This method provides valuable insights for enhancing the safety of cascade utilization of retired batteries. © 2025 Elsevier Ltd

关键词： Lithium-ion batteries

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Einstein Probe discovery of EP240408a:A peculiar X-ray transient with an intermediate timescale

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Science China(Physics,Mechanics & Astronomy) 2025年第1期68卷 218-236页

作者： Wenda Zhang Weimin Yuan Zhixing Ling Yong Chen Nanda Rea Arne Rau Zhiming Cai Huaqing Cheng Francesco Coti Zelati Lixin Dai Jingwei Hu Shumei Jia Chichuan Jin Dongyue Li Paul O’Brien Rongfeng Shen Xinwen Shu Shengli Sun Xiaojin Sun Xiaofeng Wang Lei Yang Bing Zhang Chen Zhang Shuang-Nan Zhang Yonghe Zhang Jie An David Buckley Alexis Coleiro Bertrand Cordier Liming Dou Rob Eyles-Ferris Zhou Fan Hua Feng Shaoyu Fu Johan P.U.Fynbo Lluis Galbany Saurabh W.Jha Shuaiqing Jiang Albert Kong Erik Kuulkers Weihua Lei Wenxiong Li Bifang Liu Mingjun Liu Xing Liu Yuan Liu Zhu Liu Chandreyee Maitra Alessio Marino Itumeleng Monageng Kirpal Nandra Jeremy Sanders Roberto Soria Lian Tao Junfeng Wang Song Wang Tinggui Wang Zhongxiang Wang Qingwen Wu Xuefeng Wu Dong Xu Yanjun Xu Suijian Xue Yongquan Xue Zijian Zhang Zipei Zhu Hu Zou Congying Bao Fansheng Chen Houlei Chen Tianxiang Chen Wei Chen Yehai Chen Yifan Chen Chenzhou Cui Weiwei Cui Yanfeng Dai Dongwei Fan Ju Guan Dawei Han Dongjie Hou Haibo Hu Maohai Huang Jia Huo Zhenqing Jia Bowen Jiang Ge Jin Chengkui Li Junfei Li Longhui Li Maoshun Li Wei Li Zhengda Li Tianying Lian Congzhan Liu Heyang Liu Huaqiu Liu Fangjun Lu Laidan Luo Jia Ma Xuan Mao Haiwu Pan Xin Pan Liming Song Hui Sun Yunyin Tan Qingjun Tang Yihan Tao Hao Wang Juan Wang Lei Wang Wenxin Wang Yilong Wang Yusa Wang Qinyu Wu Haitao Xu Jingjing Xu Xinpeng Xu Yunfei Xu Zhao Xu Changbin Xue Yulong Xue Ailiang Yan Haonan Yang Xiongtao Yang Yanji Yang Juan Zhang Mo Zhang Wenjie Zhang Zhen Zhang Zhen Zhang Ziliang Zhang Donghua Zhao Haisheng Zhao Xiaofan Zhao Zijian Zhao Hongyan Zhou Yilin Zhou Yuxuan Zhu Zhencai Zhu National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China School of Astronomy and Space Sciences University of Chinese Academy of SciencesBeijing 100049China Key Laboratory of Particle Astrophysics Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China Institute of Space Sciences(ICE) CSICBarcelona E-08193Spain Institut d’Estudis Espacials de Catalunya(IEEC) Barcelona E-08034Spain Max Planck Institute for Extraterrestrial Physics Garching 85748Germany Innovation Academy for Microsatellites Chinese Academy of SciencesShanghai 201210China Department of Physics University of Hong KongHong Kong 999077China School of Physics and Astronomy University of LeicesterLeicester LE17RHUK School of Physics and Astronomy Sun Yat-sen UniversityZhuhai 519082China Department of Physics Anhui Normal UniversityWuhu 241002China Shanghai Institute of Technical Physics Chinese Academy of SciencesShanghai 200083China Physics Department Tsinghua UniversityBeijing 100084China Nevada Center for Astrophysics University of Nevada Las VegasLas Vegas NV 89154USA Department of Physics and Astronomy University of Nevada Las VegasLas Vegas NV 89154USA South African Astronomical Observatory Cape Town 7935South Africa Department of Astronomy University of Cape TownRondebosch 7701South Africa Department of Physics University of the Free StateBloemfontein 9300South Africa Universit´e Paris Cit´e CNRSAstroparticule et CosmologieParis F-75013France Universit´e Paris Cit´e CEA Paris-SaclayIRFU/DAp-AIMGif-sur-Yvette 91191France Department of Astronomy Guangzhou UniversityGuangzhou 510006China Cosmic Dawn Center(DAWN) Copenhagen 2200Denmark Niels Bohr Institute University of CopenhagenCopenhagen 2200Denmark Department of Physics and Astronomy Rutgersthe State University of New JerseyPiscataway NJ 08854-8019USA Institute for Cosmic Ray Research The University of TokyoKashiwa City 277-8582Japan ESA/ESTEC Noordwijk 2201 AZThe Netherlands Department of Astronom

We report the discovery of a peculiar X-ray transient,EP240408a,by Einstein Probe(EP)and follow-up studies made with EP,Swift,NICER,GROND,ATCA and other ground-based multiwavelength *** new transient was first detected with Wide-field X-ray Telescope(WXT)on board EP on April 8th,2024,manifested in an intense yet brief X-ray flare lasting for 12 *** flare reached a peak flux of 3:9×10^(−9) erg cm^(−2) s^(−1) in 0.5-4 keV,∼300 times brighter than the underlying X-ray emission detected throughout the *** and more precise follow-up observations by EP/FXT,Swift and NICER confirmed the finding of this new *** X-ray spectrum is non-thermal in 0.5-10 keV,with a power-law photon index varying within *** X-ray light curve shows a plateau lasting for∼4 d,followed by a steep decay till becoming undetectable∼10 d after the initial *** on its temporal property and constraints from previous EP observations,an unusual timescale in the range of 7-23 d is found for EP240408a,which is intermediate between the commonly found fast and long-term *** counterparts have been found in optical and near-infrared,with the earliest observation at 17 h after the initial X-ray detection,suggestive of intrinsically weak emission in these *** demonstrate that the remarkable properties of EP240408a are inconsistent with any of the transient types known so far,by comparison with,in particular,jetted tidal disruption events,gamma-ray bursts,X-ray binaries and fast blue optical *** nature of EP240408a thus remains an *** suggest that EP240408a may represent a new type of transients with intermediate timescales of the order of∼10 *** detection and follow-ups of more of such objects are essential for revealing their origin.

关键词： X-ray transients Einstein Probe

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