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Anomalous Direct-Current Josephson Effect in Semiconductor Nanowire Junctions
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作者 伍滨和 封许昱 +2 位作者 王超 徐晓峰 王春瑞 《Chinese Physics Letters》 SCIE CAS CSCD 2016年第1期118-122,共5页
We investigate the dc Josephson effect in one-dimensional junctions where a ring conductor is sandwiched between two semiconductor nanowires with proximity-induced superconductivity. Peculiar features of the Josephson... We investigate the dc Josephson effect in one-dimensional junctions where a ring conductor is sandwiched between two semiconductor nanowires with proximity-induced superconductivity. Peculiar features of the Josephson effect arise due to the interplay of spin-orbit interaction and external Zeenmn field. By tuning the Zeeman field orientation, the device can vary from 0 to π junction. Afore importantly, nonzero ,losephson current is possible at zero phase difference across the junction. Although this anomalous Josephson current is not relevant to the topological phase transition, its magnitude can be significantly enhanced whe, n the nanowire, s become topological superconductors where Majorana bound states emerge. Distinct modulation patterns are obtained for the semiconductor nanowires in the topologically trivial and non-trivial phases. These results are useful to probe the topological phase transition in semiconductor nanowire junctions via the dc Josephson effect. 展开更多
关键词 of IS on in for Anomalous direct-current Josephson Effect in Semiconductor Nanowire Junctions SOI
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Effects of the sputtering power on the crystalline structure and optical properties of the silver oxide films deposited using direct-current reactive magnetron sputtering
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作者 郜小勇 张增院 +3 位作者 马姣民 卢景霄 谷锦华 杨仕娥 《Chinese Physics B》 SCIE EI CAS CSCD 2011年第2期370-375,共6页
This paper reports that a series of silver oxide (AgzO) films are deposited on glass substrates by direct-current reactive magnetron sputtering at a substrate temperature of 250 ℃ and an oxygen flux ratio of 15:18... This paper reports that a series of silver oxide (AgzO) films are deposited on glass substrates by direct-current reactive magnetron sputtering at a substrate temperature of 250 ℃ and an oxygen flux ratio of 15:18 by modifying the sputtering power (SP). The AgxO films deposited apparently show a structural evolution from cubic biphased (AgO + Ag20) to cubic single-phased (Ag20), and to biphased (Ag20 + AgO) structure. Notably, the cubic single-phased Ag20 fihn is deposited at the SP = 105 W and an AgO phase with (220) orientation discerned in the Ag^O films deposited using the SP 〉 105 W. The transmissivity and refiectivity of the AgxO films in transparent region decrease with the increase the SP, whereas the absorptivity inversely increases with the increase of the SP. These results may be due to the structural evolution and the increasing film thickness. A redshift of the films' absorption edges determined in terms of Tauc formula clearly occurs from 3.1 eV to 2.73 eV with the increase of the SP. 展开更多
关键词 Ag2O film direct-current reactive magnetron sputtering x-ray diffraction optical prop-erties
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Structural,Morphological and Electrical Properties of In-Doped Zinc Oxide Nanostructure Thin Films Grown on p-Type Gallium Nitride by Simultaneous Radio-Frequency Direct-Current Magnetron Co-Sputtering
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作者 R.Perumal Z.Hassan R.Saravanan 《Chinese Physics Letters》 SCIE CAS CSCD 2016年第6期77-80,共4页
Zinc oxide (ZnO) is one of the most promising and frequently used semiconductor materials. In-doped nanos- tructure ZnO thin films are grown on p-type gallium nitride substrates by employing the simultaneous rf and ... Zinc oxide (ZnO) is one of the most promising and frequently used semiconductor materials. In-doped nanos- tructure ZnO thin films are grown on p-type gallium nitride substrates by employing the simultaneous rf and dc magnetron co-sputtering technique. The effect of In-doping on structural, morphological and electrical properties is studied. The different dopant concentrations are accomplished by varying the direct current power of the In target while keeping the fixed radio frequency power of the ZnO target through the co-sputtering deposition technique by using argon as the sputtering gas at ambient temperature. The structural analysis confirms that all the grown thin films preferentially orientate along the c-axis with the wurtzite hexagonal crystal structure without having any kind of In oxide phases. The presenting Zn, 0 and In elements' chemical compositions are identified with EDX mapping analysis of the deposited thin films and the calculated M ratio has been found to decrease with the increasing In power. The surface topographies of the grown thin films are examined with the atomic force microscope technique. The obtained results reveal that the grown film roughness increases with the In power. The Hall measurements ascertain that all the grown films have n-type conductivity and also the other electrical parameters such as resistivity,mobility and carrier concentration are analyzed. 展开更多
关键词 ZnO of Structural Morphological and Electrical Properties of In-Doped Zinc Oxide Nanostructure Thin Films Grown on p-Type Gallium Nitride by Simultaneous Radio-Frequency direct-current Magnetron Co-Sputtering that by were been In EDX on
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Bidirectional rotating direct-current triboelectric nanogenerator with self-adaptive mechanical switching for harvesting reciprocating motion
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作者 Donghan Lee Joonmin Chae +6 位作者 Sumin Cho Jong Woo Kim Awais Ahmad Mohammad Rezaul Karim Moonwoo La Sung Jea Park Dongwhi Choi 《International Journal of Extreme Manufacturing》 SCIE EI CAS CSCD 2024年第4期324-335,共12页
Amid the growing interest in triboelectric nanogenerators(TENGs)as novel energy-harvesting devices,several studies have focused on direct current(DC)TENGs to generate a stable DC output for operating electronic device... Amid the growing interest in triboelectric nanogenerators(TENGs)as novel energy-harvesting devices,several studies have focused on direct current(DC)TENGs to generate a stable DC output for operating electronic devices.However,owing to the working mechanisms of conventional DC TENGs,generating a stable DC output from reciprocating motion remains a challenge.Accordingly,we propose a bidirectional rotating DC TENG(BiR-TENG),which can generate DC outputs,regardless of the direction of rotation,from reciprocating motions.The distinct design of the BiR-TENG enables the mechanical rectification of the alternating current output into a rotational-direction-dependent DC output.Furthermore,it allows the conversion of the rotational-direction-dependent DC output into a unidirectional DC output by adapting the configurations depending on the rotational direction.Owing to these tailored design strategies and subsequent optimizations,the BiR-TENG could generate an effective unidirectional DC output.Applications of the BiR-TENG for the reciprocating motions of swinging doors and waves were demonstrated by harnessing this output.This study demonstrates the potential of the BiR-TENG design strategy as an effective and versatile solution for energy harvesting from reciprocating motions,highlighting the suitability of DC outputs as an energy source for electronic devices. 展开更多
关键词 direct-current triboelectric nanogenerator mechanical rectification self-adaptive mechanical design harvesting reciprocation motion
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Analyses of nonequilibrium transport in atmospheric-pressure direct-current argon discharge under different modes
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作者 Ziming ZHANG Chuan FANG +2 位作者 Yaoting WANG Lanyue LUO Heping LI 《Plasma Science and Technology》 SCIE EI CAS CSCD 2024年第11期107-126,共20页
The key plasma parameters under different discharge modes, such as heavy-particle and electron temperatures, electron number density, and nonequilibrium volume of plasmas, play important roles in various applications ... The key plasma parameters under different discharge modes, such as heavy-particle and electron temperatures, electron number density, and nonequilibrium volume of plasmas, play important roles in various applications of gas discharge plasmas. In this study, a self-consistent two-dimensional nonequilibrium fluid model coupled with an external circuit model is established to reveal the mechanisms related to the discharge modes, including the normal glow, abnormal glow,arc, and glow-to-arc transition modes, with an atmospheric-pressure direct-current(DC) argon discharge as a model plasma system. The modeling results show that, under different discharge modes, the most significant difference between the preceding four discharge modes lies in the current and energy transfer processes on the cathode side. On one hand, the current to the cathode surface is mainly delivered by the ions coming from the plasma column under the glow discharge mode due to the low temperature of the solid cathode, whereas the thermionic and secondary electrons emitted from the hot cathode surface play a very important role under the arc mode with a higher cathode surface temperature and higher ion flux toward the cathode. On the other hand, the energy transfer channel on the cathode side changes from mainly heating the solid cathode under the glow mode to simultaneously heating both the solid cathode and plasma column under the arc mode with an increase in the discharge current. Consequently, the power density in the cathode sheath(P_c) was used as a key parameter for judging different discharge modes, and the range of(0.28–1.2) × 10^(12) W m^(-3) was determined as a critical window of P_c corresponding to the glow-to-arc-mode transition for the atmospheric-pressure DC argon discharge, which was also verified by comparison with the experimental results in this study and the data in the previous literature. 展开更多
关键词 atmospheric-pressure plasma direct-current gas discharge discharge mode mode transition power density in cathode sheath
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Modeling of Pulsed Direct-Current Glow Discharge
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作者 杜木 郑亚茹 +3 位作者 范宇佳 张楠 刘成森 王德真 《Plasma Science and Technology》 SCIE EI CAS CSCD 2010年第4期447-451,共5页
A self-consistent model was adopted to study the time evolution of low-voltage pulsed DC glow discharge. The distributions of electric field, ion density and electron density in nitrogen were investigated in our simul... A self-consistent model was adopted to study the time evolution of low-voltage pulsed DC glow discharge. The distributions of electric field, ion density and electron density in nitrogen were investigated in our simulation, and the temporal shape of the discharge current was also obtained. Our results show that the dynamic behaviors of the discharge depends strongly on the applied pulse voltage, and the use of higher pulse voltages results in a significantly increase of discharge current and a decrease of discharge delay time. The current-voltage characteristic cMculated by adjusting secondary electron emission coefficient for different applied pulse voltage under the gas pressure of 1 Torr is found in a reasonable agreement with the experimental results. 展开更多
关键词 pulsed direct-current glow discharge plasma processing plasma simulation
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Research on corona discharge suppression of high-voltage direct-current transmission lines based on dielectric-film-covered conductor
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作者 Yuze JIANG Qiying LI +4 位作者 Xuekai ZHANG Diwen JIANG Shiqiang LIU Bangfa PENG Jie LI 《Plasma Science and Technology》 SCIE EI CAS CSCD 2021年第2期64-75,共12页
Corona discharge suppression for high-voltage direct-current(HVDC)transmission lines at line terminals such as converter stations is a subject that requires attention.In this paper,a method based on a conductor covere... Corona discharge suppression for high-voltage direct-current(HVDC)transmission lines at line terminals such as converter stations is a subject that requires attention.In this paper,a method based on a conductor covered with dielectric film is proposed and implemented through a bench-scale setup.Compared with the bare conductor,the corona discharge suppression effect of the dielectric-film-covered conductor under positive polarity is studied from the composite field strength and ion current density using a line-plate experimental device.The influences of film thickness and film material on the corona discharge suppression effect are investigated.The charge accumulation and dissipation characteristics of different film materials are also studied.The results show that the conductor covered with dielectric film has excellent ability to inhibit corona discharge.The ground-level composite field strength of the conductor covered with dielectric film is lower than its nominal field strength,and its ion current density is at the nA m^(−2) level.The corona threshold voltage can be promoted by increasing the film thickness,but the ability to inhibit corona discharge becomes weak.The larger the surface electric field strength,the more charge accumulated,but the faster the charge dissipation rate.Compared with polyvinyl chloride film,cross-linked polyethylene film has stronger charge accumulation ability and slower charge dissipation rate,which can better restrain the corona discharge of HVDC transmission lines. 展开更多
关键词 high-voltage direct-current(HVDC)transmission lines corona discharge suppression dielectric-film-covered conductor composite field strength ion current density
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Three modes of a direct-current plasma jet operated underwater to degrade methylene blue 被引量:5
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作者 Xuechen LI Biao WANG +3 位作者 Pengying JIA Linwei YANG Yaru LI Jingdi CHU 《Plasma Science and Technology》 SCIE EI CAS CSCD 2017年第11期75-81,共7页
A direct-current air plasma jet operated underwater presents three stable modes including an intermittently-pulsed discharge, a periodically-pulsed discharge and a continuous discharge with increasing the power voltag... A direct-current air plasma jet operated underwater presents three stable modes including an intermittently-pulsed discharge, a periodically-pulsed discharge and a continuous discharge with increasing the power voltage. The three discharge modes have different appearances for the plasma plumes. Moreover, gap voltage-current characteristics indicate that the continuous discharge is in a normal glow regime. Spectral lines from reactive species(OH, N2, N2^+, Hα,and O) have been revealed in the emission spectrum of the plasma jet operated underwater.Spectral intensities emitted from OH radical and oxygen atom increase with increasing the power voltage or the gas flow rate, indicating that reactive species are abundant. These reactive species cause the degradation of the methylene blue dye in solution. Effects of the experimental parameters such as the power voltage, the gas flow rate and the treatment time are investigated on the degradation efficiency. Results indicate that the degradation efficiency increases with increasing the power voltage, the gas flow rate or the treatment time. Compared with degradation in the intermittently-pulsed mode or the periodically-pulsed one, it is more efficient in the continuous mode, reaching 98% after 21 min treatment. 展开更多
关键词 plasma jet direct current glow discharge plasma degradation methylene blue
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Intelligent algorithm-based maximum power point tracker for an off-grid photovoltaic-powered direct-current irrigation system 被引量:1
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作者 Hussain Attia Maen Takruri Ali Al-Ataby 《Clean Energy》 EI CSCD 2024年第3期48-61,共14页
This research aims to enhance the performance of photovoltaic(PV)systems on a 2-fold basis.Firstly,it introduces an advanced deep artificial neural network algorithm for accurate and fast maximum power point tracking,... This research aims to enhance the performance of photovoltaic(PV)systems on a 2-fold basis.Firstly,it introduces an advanced deep artificial neural network algorithm for accurate and fast maximum power point tracking,ensuring optimal extraction of electrical power from PV arrays.Secondly,it proposes the use of 96-V,2.98-kW direct-current(DC)water pumps for farm irrigation,aiming to improve efficiency,reduce cost and complexity,and overcome challenges associated with connecting faraway farm irrigation systems to the utility grid.In this study,it has been demonstrated that the use of DC pumps greatly improves system performance and efficiency by eliminating the need for isolation transformers,power passive filters and inverters,therefore simplifying the architecture of the system.The efficacy of the proposed methodology is confirmed by MATLAB®/Simulink®simulation results,whereby the proposed algorithm attains a mean squared error of 6.5705×10^(-5)and a system efficiency approaching 99.8%,ensuring a steady voltage under varying load conditions. 展开更多
关键词 artificial neural network photovoltaic arrays maximum power point tracking buck converter direct-current irrigation systems MATLAB/SIMULINK
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基于非线性增益超螺旋滑模观测器的无刷直流电机控制
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作者 胡鸿志 苏弘杰 +3 位作者 颜宝贤 苏海涛 管芳 徐翠锋 《组合机床与自动化加工技术》 北大核心 2026年第2期85-90,95,共7页
针对传统超螺旋滑模观测器(ST-SMO)在无传感器无刷直流电机控制过程中存在高频抖振以及转子位置观测滞后的问题,提出一种基于非线性增益的超螺旋滑模观测器(NGST-SMO)。在超螺旋算法中引入非线性增益及线性项,提高算法的收敛速度;采用so... 针对传统超螺旋滑模观测器(ST-SMO)在无传感器无刷直流电机控制过程中存在高频抖振以及转子位置观测滞后的问题,提出一种基于非线性增益的超螺旋滑模观测器(NGST-SMO)。在超螺旋算法中引入非线性增益及线性项,提高算法的收敛速度;采用softsign函数代替传统的符号函数,消除SMO观测反电动势中的高频分量;针对无传感器控制系统中速度环控制抗扰动能力差的问题,将NGST-SMO与扰动观测器结合,提升闭环控制系统的抗扰动能力,增强系统的鲁棒性。基于仿真模型和BLDC试验平台的实验表明,在所提出的NGST-SMO控制下,相比ST-SMO观测转速的抖振降低了78%,转子位置观测误差降低85%,并且提高了系统的动态响应性能。 展开更多
关键词 滑模观测器 无传感器控制 扰动观测器 无刷直流电机
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大容量同步发电机源故障分析与开断需求
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作者 温伟杰 范晶涵 +2 位作者 靳鹤志 王晓远 李斌 《电网技术》 北大核心 2026年第1期221-230,I0106-I0112,共17页
现有大容量发电机断路器(generator circuit breaker,GCB)采用SF6气体灭弧,存在不环保、开断速度慢、长期被国外技术垄断等问题。为从系统层面厘清大容量同步发电机源故障电流特点及其对GCB的开断需求,该文研究了大容量发电机源故障电... 现有大容量发电机断路器(generator circuit breaker,GCB)采用SF6气体灭弧,存在不环保、开断速度慢、长期被国外技术垄断等问题。为从系统层面厘清大容量同步发电机源故障电流特点及其对GCB的开断需求,该文研究了大容量发电机源故障电流特有的延时过零机理,发现阻尼绕组与定子绕组间的强磁耦合作用是导致故障电流延时过零的根本原因,而非传统认知的高电抗/电阻比值(X/R);揭示了阻尼绕组材料、故障相位角、励磁状态、转速等对故障电流幅值和延时过零等特性的影响规律。以实际工程应用的1200MW核电机组为例,构建了其有限元仿真模型,对相关研究结论进行了仿真验证,总结归纳出环保型大容量GCB的特殊开断需求。研究结论可为研发环保型大容量快速GCB提供指导和依据。 展开更多
关键词 故障电流 延时过零 发电机断路器 直流阻尼
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经颅直流电刺激干预后非稳定杠铃卧推运动表现及肌电活动变化
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作者 王乐军 池雯欣 +3 位作者 宋筱倩 李倩 乔敏洁 陶海峰 《中国组织工程研究》 北大核心 2026年第23期6099-6109,共11页
背景:经颅直流电刺激可以通过调节大脑皮质兴奋性提高人体运动表现,但其对非稳定负荷运动任务表现的影响仍不明确。目的:探讨经颅直流电刺激对非稳定杠铃卧推运动表现及肌电活动的影响。方法:采用随机、自身对照交叉试验设计,22名男性... 背景:经颅直流电刺激可以通过调节大脑皮质兴奋性提高人体运动表现,但其对非稳定负荷运动任务表现的影响仍不明确。目的:探讨经颅直流电刺激对非稳定杠铃卧推运动表现及肌电活动的影响。方法:采用随机、自身对照交叉试验设计,22名男性大学生受试者接受随机的真刺激(阳极刺激)和假刺激2种经颅直流电刺激干预,分别在经颅直流电刺激干预后对受试者进行非稳定杠铃卧推疲劳试验,记录完成卧推动作的次数和卧推运动中杠铃杆的加速度,作为反映非稳定杠铃卧推负荷任务运动表现和动作稳定性控制能力表现的指标。此外,采集运动过程中右侧肱二头肌、肱三头肌、三角肌前束、三角肌后束以及胸大肌的表面肌电信号。采用配对t检验对真、假刺激条件下的卧推次数差异性进行检验;采用重复测量设计的方差分析对三轴加速度、主动肌激活水平和拮抗肌共激活水平等指标的差异性进行检验。结果与结论:①真、假刺激干预后受试者卧推杠铃次数无显著差异,但经颅直流电刺激真刺激干预后Y轴的加速度平均幅值均显著小于经颅直流电刺激假刺激时;②经颅直流电刺激真刺激干预显著提升了三角肌前束的激活水平和三角肌后束的共激活水平;除三角肌后束外,各测试肌肉运动后半段的激活水平显著高于运动前半段;③经颅直流电刺激干预和运动阶段对各测试指标的影响无显著的交互作用;④提示经颅直流电刺激对非稳定杠铃卧推运动的肌肉耐力表现并无显著影响,但可以提高动作的稳定性,这可能与经颅直流电刺激可以显著提高三角肌前束激活水平和三角肌后束共激活水平,进而提高肩关节的刚度和稳定性有关;在竞技体育和临床康复训练中,可以根据训练目的考虑采用经颅直流电刺激调控非稳定负荷运动任务的表现。 展开更多
关键词 经颅直流电刺激 真刺激 假刺激 非稳定负荷运动任务 动作稳定性 表面肌电信号
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多馈入直流系统换相失败抵御能力评价与提升方法综述
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作者 辛业春 黄韬宇 +3 位作者 王拓 赫羽朋 甘效罗 李国庆 《电力工程技术》 北大核心 2026年第1期13-25,105,共14页
多馈入直流(multi-infeed direct current,MIDC)系统换相失败抵御能力的评价与提升方法,对实际电网系统换相失败特性的测试、评估难题的解决以及换相失败防御技术在电网规划与运行中的应用具有重要意义,因此文中对其进行系统科学的归纳... 多馈入直流(multi-infeed direct current,MIDC)系统换相失败抵御能力的评价与提升方法,对实际电网系统换相失败特性的测试、评估难题的解决以及换相失败防御技术在电网规划与运行中的应用具有重要意义,因此文中对其进行系统科学的归纳和总结。首先,阐述MIDC系统以及换相失败的基本定义,分析不同类型故障对换相失败的影响,梳理其关键影响因素,并总结现有换相失败判据;其次,综述目前已有的换相失败抵御能力评价方法;然后,从无功补偿优化、控制保护优化以及换流器拓扑改进等3个方面对现阶段MIDC系统换相失败抵御能力提升方法进行综述;最后,明确了未来需要重点关注以下方向:采用归一化的效果评价方式,在具备标准意义的仿真平台上开展可重复的校检,形成系统性、综合性的换相失败抵御能力评价方法,并提出包括换流站级、换流器级和系统级的多层次协同提升策略。 展开更多
关键词 高压直流输电 多馈入直流(MIDC)系统 换相失败 抵御能力 评价方法 防御技术
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毒性仪光电倍增管高压直流电源设计
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作者 姚铃丽 王涛 +1 位作者 陈冬峰 陈庆荣 《现代电子技术》 北大核心 2026年第6期37-42,共6页
为满足光电式毒性测试仪器中光电倍增管对稳定高压供电的需求,设计一种专用高压直流电源。采用文氏桥振荡器生成正弦信号,经比较器与基准电平对比形成PWM信号;通过MOSFET驱动隔离变压器,结合二极管倍压整流实现升压;利用运算放大器与双... 为满足光电式毒性测试仪器中光电倍增管对稳定高压供电的需求,设计一种专用高压直流电源。采用文氏桥振荡器生成正弦信号,经比较器与基准电平对比形成PWM信号;通过MOSFET驱动隔离变压器,结合二极管倍压整流实现升压;利用运算放大器与双光耦完成线性取样和隔离输出,调节比较器基准电平以稳压。过压保护采用TVS管,过流保护通过电流取样触发可控硅切断初级绕组电流。测试结果表明,所设计电源可调输出为800~1200 V,纹波小于0.2%,静态功耗小于0.5 W,效率大于70%,可保障光电倍增管稳定工作及光电式毒性测试仪可靠运行。 展开更多
关键词 光电倍增管 高压直流电源 光电式毒性测试仪器 脉宽调制 二极管倍压整流 双光耦隔离
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基于匹配控制的海上风电柔直送出系统联动调频控制策略
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作者 崔学深 张宾宾 +3 位作者 刘其辉 申旭辉 李铮 孙栩 《现代电力》 北大核心 2026年第1期49-59,共11页
大规模海上风电柔性直流送出系统(voltage source converter based high voltage direct current,VSC-HVDC)可以通过双端换流站的联动作用调节风电机组功率,提升陆上电网的调频能力。为解决远海风电场输出功率与陆上电网频率耦合性差和... 大规模海上风电柔性直流送出系统(voltage source converter based high voltage direct current,VSC-HVDC)可以通过双端换流站的联动作用调节风电机组功率,提升陆上电网的调频能力。为解决远海风电场输出功率与陆上电网频率耦合性差和响应滞后的问题,该文提出一种基于匹配控制的陆海换流站协同调频方法。该策略采用双端对称的匹配控制结构,将陆上电网的频率变化通过VSC-HVDC直流电压耦合传递至海上风电侧,并在风电变流器中结合虚拟同步机技术与自适应变阻尼减载控制,使得各风电机组无需通信即可快速响应陆上电网频率波动,动态提供频率支撑功率。通过MATLAB/Simulink软件建立大容量等值直驱型风电机组经VSC-HVDC并网的仿真模型,在弱电网条件下仿真验证了基于匹配控制的VSC-HVDC与海上风电系统联动调频策略的有效性。 展开更多
关键词 联动调频 构网型控制 匹配控制 海上风电 柔性直流输电系统
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基于环流的同步调相机不同位置定子匝间短路故障诊断
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作者 李俊卿 黄涛 +3 位作者 韩小平 张承志 苑浩 何玉灵 《电力工程技术》 北大核心 2026年第1期125-133,共9页
同步调相机作为特高压直流输电系统中提供无功补偿和电压支撑的重要设备,其运行安全性与可靠性对直流输电工程意义重大。针对轻微定子匝间短路难以诊断以及故障槽难以定位的问题,文中提出一种基于定子支路环流的故障诊断方法。首先,从... 同步调相机作为特高压直流输电系统中提供无功补偿和电压支撑的重要设备,其运行安全性与可靠性对直流输电工程意义重大。针对轻微定子匝间短路难以诊断以及故障槽难以定位的问题,文中提出一种基于定子支路环流的故障诊断方法。首先,从定子支路单个线圈磁动势出发,分析定子匝间短路故障位置对电枢磁动势以及定子支路环流的影响。其次,搭建同步调相机定子匝间短路的场-路耦合模型,对不同位置下定子匝间短路的故障特征进行仿真。最后,总结不同匝间短路故障位置下定子支路环流的变化规律。仿真和实验结果表明,在同步调相机发生相同匝数的定子匝间短路时,短路位置越靠近支路绕组轴线位置,定子支路环流幅值越大;短路位置越远离绕组轴线位置,定子支路环流幅值越小。 展开更多
关键词 同步调相机 定子匝间短路 定子支路环流 故障定位 故障诊断 特高压直流输电系统
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基于DR和VSC海上风电HVDC系统的并联运行控制
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作者 宁金叶 覃事刚 +1 位作者 徐谦 黄成菊 《电源学报》 北大核心 2026年第1期262-270,共9页
为了实现海上风力发电高比例友好消纳的目标,提出了1种基于二极管整流器DR(diode rectifier)高压直流HVDC(high-voltage direct current)输电系统和电压源换流器VSC(voltage source converter)HVDC输电系统并联运行的新型控制方法。这2... 为了实现海上风力发电高比例友好消纳的目标,提出了1种基于二极管整流器DR(diode rectifier)高压直流HVDC(high-voltage direct current)输电系统和电压源换流器VSC(voltage source converter)HVDC输电系统并联运行的新型控制方法。这2条线路均与海上风电场OWFs(offshore wind farms)连接,VSC-HVDC输电系统控制海上交流电网的电压和频率,即基于控制VSC-HVDC输电系统交流母线的有功功率平衡来控制OWFs的电压。当OWFs注入功率超过VSC-HVDC输电系统有功功率参考值时,OWFs电压升高,DR-HVDC输电系统激活,此时海上交流电网通过DR-HVDC线路传输OWFs所需的功率值,而系统频率由VSC-HVDC输电系统通过满足无功功率平衡来实现控制;当VSC-HVDC输电系统传输的功率与设定值相同时,DR-HVDC输电系统将自动关闭。所提方法的最大优点在于VSC-HVDC输电系统的容量仅用于支持系统正常运行,一旦OWFs投入运行,DR-HVDC输电系统将自动激活。最后,仿真结果验证了所提方法的有效性和优越性。 展开更多
关键词 海上风电场 高压直流 二极管整流单元 电压源变流器 频率控制 并联运行控制
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高压直流输电系统换流变分接开关专用保护方案
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作者 莫品豪 顾乔根 +2 位作者 张晓宇 郑超 孙仲民 《电气技术》 2026年第1期28-34,共7页
换流变是高压直流输电系统中的核心设备,决定着直流输电系统的安全稳定运行。近年来,有多起因换流变分接开关故障导致的换流变损毁、直流停运事故发生。从继电保护角度看,传统换流变保护配置方案反应换流变分接开关故障存在速动性差、... 换流变是高压直流输电系统中的核心设备,决定着直流输电系统的安全稳定运行。近年来,有多起因换流变分接开关故障导致的换流变损毁、直流停运事故发生。从继电保护角度看,传统换流变保护配置方案反应换流变分接开关故障存在速动性差、灵敏度不足的问题。本文在研究换流变分接开关故障机理的基础上,提出一种换流变分接开关的专用保护方案。该方案同时采集并利用换流变电气量和非电气量信息,引入正弦信号半周绝对值积分算法,由计及换流变挡位信息的快速差动保护判据和非电气量检测判据共同构成。理论分析和仿真实验结果表明,该保护方案在不降低可靠性的前提下,其动作速度相对传统换流变保护快15 ms,可解决当前因换流变分接开关故障切除时间过长而导致的换流变损毁问题。 展开更多
关键词 高压直流输电(HVDC) 换流变 分接开关 差动保护
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电机滑行状态下霍尔位置传感器的偏差校正方法
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作者 陈炜 隋月帅 阎彦 《天津工业大学学报》 北大核心 2026年第1期63-69,共7页
针对无刷直流电机霍尔位置传感器受到安装精度的限制容易出现安装偏差的问题,提出了一种在电机自由滑行状态下的霍尔位置传感器安装偏差校正方法。关断逆变器开关管的开关信号,电机进入滑行状态,通过构造虚拟中性点检测反电动势(ZMF)过... 针对无刷直流电机霍尔位置传感器受到安装精度的限制容易出现安装偏差的问题,提出了一种在电机自由滑行状态下的霍尔位置传感器安装偏差校正方法。关断逆变器开关管的开关信号,电机进入滑行状态,通过构造虚拟中性点检测反电动势(ZMF)过零点信息,识别霍尔位置传感器的安装偏差。结果表明:所提方法可以有效避免开关管斩波对反电动势过零点检测的干扰,提高反电动势过零点信号的检测精度,有利于霍尔位置传感器偏差角度识别;当A、B、C相霍尔位置传感器分别引入安装偏差约为滞后15°和超前10°、0°电角度时,校正后三相霍尔信号的绝对误差分别约为超前0.3°、超前1.22°和滞后0.77°电角度。 展开更多
关键词 无刷直流电机 霍尔位置传感器 安装偏差 自由滑行状态 反电动势过零点
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基于交互电流扩展小干扰互联矩阵的同步发电机-等效异构风电场-高压直流系统低频振荡抑制
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作者 李生虎 陶帝文 《中国电机工程学报》 北大核心 2026年第4期1407-1419,I0009,共14页
同步发电机(synchronous generator,SG)、风电场、高压直流(high-voltage direct current,HVDC)间交互,增加了电力系统低频振荡风险。在双馈感应电机(doubly-fed induction generator,DFIG)安装附加阻尼控制器(supplementary damping co... 同步发电机(synchronous generator,SG)、风电场、高压直流(high-voltage direct current,HVDC)间交互,增加了电力系统低频振荡风险。在双馈感应电机(doubly-fed induction generator,DFIG)安装附加阻尼控制器(supplementary damping controller,SDC),可提高小干扰稳定性。由于电网需求和安装成本,并非所有DFIG都配置SDC,从而形成异构风电场(heterogeneous wind farm,HWF)。该文提出HWF场网振荡等效模型,量化HWF-SG-HVDC交互对低频振荡影响。首先,推导SDC对应的非对角状态子矩阵。保持SDC控制效果不变,提出HWF等效方程。根据各等效DFIG输出与HWF输出间关系,建立HWF场网振荡等效模型;其次,建立HWF-SG-HVDC子结构模型。根据设备端电压和输电网络导纳,将子结构输出电流表示为交互电流叠加形式。基于组件连接法,建立计及交互作用的状态矩阵;最后,推导非线性交互矩阵,将其F-范数定义为交互强度。以交互矩阵元素为中间变量,提出关键模态对交互强度的灵敏度,进而建立抑制低频振荡优化算法。仿真结果表明:优化后系统交互强度降低24.5%,关键模态阻尼比由0.02增加至0.06。 展开更多
关键词 等效异构风电场 非线性交互矩阵 扩展组件连接法 交互灵敏度 高压直流 同步发电机 低频振荡
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