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临界电流模式图腾柱无桥功率因数校正换相谐振抑制

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电工技术学报 2024年第12期39卷 3816-3826页

作者：黄帆任小永陈乾宏李梦睿王生东南京航空航天大学自动化学院南京211106 洛阳隆盛科技有限责任公司洛阳471000 中国电子科技集团第五十五研究所南京210096

工作于临界电流模式下的图腾柱无桥功率因数校正(PFC)电路因其无整流桥损耗、电感体积小、易于实现软开关而得到广泛关注。然而,在输入电压过零点处,工频管之间的换相时刻,电感会与工频管的结电容产生谐振,相应地,电感电流和直流母线电... 详细信息

工作于临界电流模式下的图腾柱无桥功率因数校正(PFC)电路因其无整流桥损耗、电感体积小、易于实现软开关而得到广泛关注。然而,在输入电压过零点处,工频管之间的换相时刻,电感会与工频管的结电容产生谐振,相应地,电感电流和直流母线电压因此会存在高频振荡。电感电流振荡会加剧输入电流畸变程度,而母线电压上的高频尖峰由于振荡频率高,后级DC-DC变换器难以抑制而传递至负载,导致敏感负载无法正常工作。该文分析线性开关在主动栅极电路中抑制振荡的工作原理,基于线性开关的特性提出三电平驱动方式来抑制图腾柱无桥PFC换相谐振,降低输入电流总谐波畸变率(THD)的同时实现对直流母线的高频尖峰的抑制,在2kW满载工况下,将输入电流THD降低1%,母线电压尖峰高频分量峰值由2.83V减小至0.01 V以下。实验结果表明,该文所提出的三电平驱动方式可以有效抑制临界电流模式图腾柱无桥PFC的换相谐振。

关键词：图腾柱无桥功率因数校正(PFC) 换相谐振线性开关三电平驱动母线电压尖峰抑制

Unified Analysis and Output Estimation for a Strong Coupling Contactless Slipring System

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CSEE Journal of Power and Energy Systems 2023年第6期9卷 2263-2271页

作者： Guangming He qianhong chen Xiaoyong Ren Zhiliang Zhang the Jiangsu Key Laboratory of New Energy Generation and Power Conversion Nanjing University of Aeronautics and AstronauticsNanjing 210016China School of Physics and Electronic Electrical Engineering Huaiyin Normal UniversityHuai’an 223300China

A contactless slipring (CS) system utilizing inductive-power-transfer (IPT) technology is a good candidate for traditional mechanical slipring assemblies. However, suffering from the high harmonic currents in strong coupling CS systems, the output power will deviate from the theoretical values estimated by the fundamental harmonic approximation (FHA) and its extension method, i.e., E-FHA, in which the power is transferred by both the fundamental current and the high order harmonic currents. In order to achieve high precise output estimation, a unified analysis is proposed in this paper. First, “Fundamental-harmonic Double Resonance Phenomenon” is revealed via impedance analysis, to address the nature of the high harmonic currents in strong coupling systems. Then, a unified output current expression owning high precision is derived, and followed by a unified fundamental load impedance. Discussions show that both the output and the fundamental load impedance of FHA, and E-FHA are the special cases of the unified expressions proposed. FHA and E-FHA are precise enough for the loose coupling system, whereas the proposed method is indispensable for the strong coupling system with k>0.4 . Finally, simulations and experimental measurements of a 1.6kW CS system, as well as the comparative studies related to FHA, E-FHA, and the proposed method, are presented, indicating that the proposed method is effective for high precise output estimation.

关键词： Contactless slipring(CS) precise output estimation unified analysis

微生物菌肥对油茶生长、抗逆性和土壤环境的影响

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世界林业研究 2024年第3期37卷 28-32页

作者：舒惠琳胡文涛陈启洲陈惠珊陈倩虹黄久香黄永芳潘澜华南农业大学林学与风景园林学院广州510642

微生物菌肥是一种环保、低碳、无污染的有机生物肥料,可通过增加土壤中微生物的数量和活性调整养分平衡,有效改善土壤生态环境,进而促进植物生长、增加产量和提高果实品质。文中阐述了微生物菌肥的促生抗逆作用机理,明确指出菌肥能够有... 详细信息

微生物菌肥是一种环保、低碳、无污染的有机生物肥料,可通过增加土壤中微生物的数量和活性调整养分平衡,有效改善土壤生态环境,进而促进植物生长、增加产量和提高果实品质。文中阐述了微生物菌肥的促生抗逆作用机理,明确指出菌肥能够有效促进土壤微生物活性、改善土壤理化性质、改善植物营养状况和增强植物光合作用,从而促进油茶的生长和养分吸收,提高产量及品质,并有效提高油茶抗旱能力,抑制病原菌的生长。总结微生物菌肥在油茶上的应用前景以及重点研究方向,旨在更好地推动微生物菌肥在油茶上的应用,为提高油茶品质和产量奠定基础。

关键词：油茶微生物菌肥土壤性质生理生态植物抗性

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低压大电流移相全桥变换器平面磁集成矩阵变压器的优化设计

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磁性元件与电源 2024年第5期 162-167,173页

作者：王树鹏陈乾宏韩良琪南京航空航天大学自动化学院南京210016

针对低压大电流输出的场合,为了降低器件的导通损耗和热应力,原边绕组串联,副边绕组并联的磁集成矩阵变压器被广泛应用。本文针对原副边均为低压大电流的移相全桥变换器,给出了一种原边绕组和副边绕组交错串并联的磁集成矩阵变压器结构... 详细信息

针对低压大电流输出的场合,为了降低器件的导通损耗和热应力,原边绕组串联,副边绕组并联的磁集成矩阵变压器被广泛应用。本文针对原副边均为低压大电流的移相全桥变换器,给出了一种原边绕组和副边绕组交错串并联的磁集成矩阵变压器结构,阐述其基本原理和能够同时实现原副边均流的优势,并进行了具体设计。同时,本文在Maxwell中搭建了仿真模型,并对磁芯形状和绕组布局进行了优化设计。最后,本文搭建了一台1.35kW的样机,对理论论证和设计进行了验证。

关键词：低压大电流矩阵变压器磁集成移相全桥

基于GaN的开关线性复合高速随动脉冲负载直流变换器

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电工技术学报 2024年第6期39卷 1818-1829页

作者：樊靖轩施佳楠徐子梁任小永陈乾宏南京航空航天大学江苏省新能源发电与电能变换重点实验室南京210016

有源相控阵雷达发射机收发组件工作在高频脉冲负载模式,这对其供电电源的负载动态性能提出了很高要求。该文针对高速负载切换的二次DC-DC电源,提出开关线性复合并联结构的脉冲负载变换器及其相应的控制策略。基于器件级环路建模的方法... 详细信息

有源相控阵雷达发射机收发组件工作在高频脉冲负载模式,这对其供电电源的负载动态性能提出了很高要求。该文针对高速负载切换的二次DC-DC电源,提出开关线性复合并联结构的脉冲负载变换器及其相应的控制策略。基于器件级环路建模的方法有效提升了线性稳压电路的环路带宽,使其进行快速功率跟踪,并设计基于GaN的低阻抗交错并联Buck变换器,使其以较快的速度高效地提供主要脉冲功率。针对重复频率50 kHz、峰值功率120 W的高频模拟雷达脉冲负载,该文搭建脉冲电流上升下降时间50 ns以内的脉冲电源原理样机,输出电压跌落小于5%。实验结果表明所提方法能够有效改善脉冲电源的动态性能。

关键词：脉冲电源相控阵雷达氮化镓动态响应

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无蔗糖凝固型鸡蛋酸乳的研制及其工艺优化

甘肃科技 2024年第4期40卷 58-66,71页

作者：王瑞云张建佩陈倩红田辉酒钢集团甘肃祁牧乳业有限责任公司甘肃嘉峪关735100 兰州理工大学生命科学与工程学院甘肃兰州730050

无蔗糖凝固型鸡蛋酸乳是以生牛乳为原料,添加鸡蛋液、甜味剂及稳定剂,以嗜热链球菌和保加利亚乳杆菌为发酵剂,发酵而成的酸乳。产品同时含有牛乳和鸡蛋的营养素,且未添加蔗糖。通过单因素及响应面优化试验,以感官评价为标准,确定最佳生... 详细信息

无蔗糖凝固型鸡蛋酸乳是以生牛乳为原料,添加鸡蛋液、甜味剂及稳定剂,以嗜热链球菌和保加利亚乳杆菌为发酵剂,发酵而成的酸乳。产品同时含有牛乳和鸡蛋的营养素,且未添加蔗糖。通过单因素及响应面优化试验,以感官评价为标准,确定最佳生产工艺。结果表明,产品最佳生产工艺为:甜味剂添加量7.8%(W/W),鸡蛋液添加量7.6%(W/W),稳定剂添加量0.45%(W/W),发酵时间7 h。此条件下制备的零蔗糖凝固型鸡蛋酸乳产品酸甜适中,口感爽滑,香味浓郁,营养多元。

关键词：凝固型酸奶鸡蛋液无蔗糖响应面工艺优化

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动态IPT系统后级稳压器的小信号模型修正和改进控制策略

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磁性元件与电源 2024年第5期 174-182页

作者：殷金安陈乾宏尹艳浩何明亮刘立东南京航空航天大学南京210016 横店集团东磁股份有限公司东阳322118

动态无线供电技术具有无磨损、维护成本低等优点,在自动化分栋系统中具有良好的应用价值。论文针对单轨动态无线供电系统,在考虑整流桥前的电流断续及副边谐振电路寄生参数的影响下,分析了整流电压与负载的关系,指出因负载变化导致的整... 详细信息

动态无线供电技术具有无磨损、维护成本低等优点,在自动化分栋系统中具有良好的应用价值。论文针对单轨动态无线供电系统,在考虑整流桥前的电流断续及副边谐振电路寄生参数的影响下,分析了整流电压与负载的关系,指出因负载变化导致的整流电压大范围波动给后级稳压器的建模和闭环参数设计带来了挑战。为使后级稳压器小信号模型描述的更为准确,论文考虑了副边侧谐振电路的影响,引入幅值/频率修正系数,对后级稳压器小信号模型的低频段增益和中频段谐振峰频率进行了修正。在此基础上,为进一步提高系统的变负载动态响应能力,论文提出加入整流电压前馈环节。仿真与实验结果验证了理论分析的正确性和所提方案的有效性。

关键词：动态无线电能传输寄生参数整流电压小信号模型控制策略

Scraping therapy for knee osteoarthritis: a systematic review and Meta-analysis

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Journal of Traditional Chinese Medicine 2024年第4期44卷 633-641页

作者： chen Dandan JIN qianhong SHEN Yuanjuan WANG Qing DAI Zhengxiang School of Nursing Guangxi University of Chinese Medicine School of Nursing Nanjing University of Chinese Medicine General Surgery Department Jiangsu Province Hospital of Chinese Medicine Hospital Infection Control Office Jiangsu Province Hospital of Chinese Medicine

OBJECTIVE: To systematically evaluate the efficacy of scraping therapy on knee osteoarthritis(KOA). METHODS: A computerized search was conducted in several databases, including PubMed, Web of Science, Cochrane Library, China National Knowledge Infrastructure Database, China Science and Technology Journal Database,Wanfang, and Chinese BioMedical Literature Database,from the establishment date of these databases to April 9,2023. Randomized controlled trials(RCTs) on scraping therapy for KOA were collected in accordance with the “Participants-Intervention-Control-Outcome-Study design”criteria. The methodological evaluation of the included studies was carried out using RoB 2.0, and Meta-analysis was conducted using RevMan. The Grades of Recommendations Assessment, Development and Evaluation(GRADE System) was applied to grade the quality of evidence. RESULTS: A total of 12 RCTs with 997 subjects were included in the Meta-analysis. Results indicated that compared with the control group, the scraping therapy treatment group exhibited increased Lysholm scores [mean difference(MD) = 4.96, 95% confidence intervals(CI)(3.18, 6.74), P < 0.000 01] and Hospital for Special Surgery scores [MD = 8.35, 95% CI(3.92, 12.78), P = 0.0002] and decreased visual analog scale scores [MD =-2.11, 95% CI(-3.79,-0.44), P = 0.01] and Western Ontario and McM aster University Osteoarthritis Index scores [MD =-6.77, 95% CI(-8.99,-4.56), P < 0.000 01)]. The quality of evidence obtained in this Meta-analysis was low according to the GRADE system. CONCLUSION: The available evidence suggests that scraping therapy may have certain clinical efficacy in the treatment of KOA. However, further high-quality RCTs are needed to confirm the findings.

关键词： Meta-analysis osteoarthritis, knee scraping systematic review

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Characterization of Self-driven Cascode-Configuration Synchronous Rectifiers

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Transactions of Nanjing University of Aeronautics and Astronautics 2019年第6期36卷 902-911页

作者： REN Xiaoyong LI Kunqi chen qianhong Aero-Power Sci-Tech Center College of Automation EngineeringNanjing University of Aeronautics and Astronautics

This paper presents a cascode configuration synchronous rectifier device based on silicon MOSFET and Schottky diode,which can replace traditional power diode *** structure has self-driven ability with simple external circuit,and the conduction characteristic is preferable to a power *** characterization and switching behavior analysis of proposed structure are conducted in this *** switching process is illustrated in detail using real model which considers the parasitic inductances and the nonlinearity of junction *** real time internal voltage and current value during switching transition are deduced with the equivalent *** validate the analysis,two voltage specification rectifiers are ***,double-pulse test results and the practical design example verify the performance advantages of proposed structure.

关键词： synchronous rectifier(SR) self-driven cascode structure power diode