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A sensorless and simple controller for VSC based HVDC systems

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第12期10卷 1824-1834页

作者： E. ABIRI A. RAHMATI A. ABRISHAMIFAR department of electronic and electrical Engineering Shiraz University of Technology department of electronic and electrical Engineering Iran University of Science and Technology

Voltage source converter high-voltage direct current （VSC-HVDC） is a new power transmission technology pref- erable in small or medium power transmission. In this paper we discuss a new control system based on space vector modulation （SVM） without any voltage line sensors. Using direct power control （DPC） SVM and a new double synchronous reference frame phase-locked loop （DSRF-PLL） approach, the control system is resistant to the majority of line voltage disturbances. Also, the system response has accelerated by using a feed forward power decoupled loop. The operation of this control strategy was verified in a SIMULINK/MATLAB simulation environment. To validate this control system, a 5 kV.A prototype system was constructed. Compared to the original controllers, the current total harmonic distortion （THD）, the active and reactive deviations and the DC voltage overshoot were lowered by 2.5%, 6.2% and 8%, respectively. The rectifier power factor in the worst condition was 0.93 and the DC voltage settling time was 0.2 s.

关键词： Voltage source converter high-voltage direct current (VSC-HVDC) Space vector modulation (SVM) Direct power control (DPC) HVDC Light

Bio-inspired optimization algorithms for optical parameter extraction of dielectric materials: A comparative study

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Chinese Physics B 2016年第10期25卷 202-208页

作者： Md Ghulam Saber Kh Arif Shahriar Ashik Ahmed Rakibul Hasan Sagor department of electrical and electronic Engineering Islamic University of Technology (IUT) department of electrical and electronic Engineering Northern University Bangladesh (NUB)

Particle swarm optimization(PSO) and invasive weed optimization(IWO) algorithms are used for extracting the modeling parameters of materials useful for optics and photonics research community. These two bio-inspired algorithms are used here for the first time in this particular field to the best of our knowledge. The algorithms are used for modeling graphene oxide and the performances of the two are compared. Two objective functions are used for different boundary values. Root mean square(RMS) deviation is determined and compared.

关键词： optical parameter extraction particle swarm optimization invasive weed optimization graphene oxide optimization

Dominant edge direction based fast intra mode decision in the H.264/AVC encoder

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第6期10卷 767-777页

作者： Byeongdu LA Minyoung EOM Yoonsik CHOE department of electrical and electronic Engineering Yonsei University

The H.264/AVC video coding standard uses an intra prediction mode with 4×4 and 16×16 blocks for luma and 8×8 blocks for chroma. This standard uses the rate distortion optimization (RDO) method to determine the best coding mode based on the compression performance and video quality. This method offers a large improvement in coding efficiency compared to other compression standards, but the computational complexity is greater due to the various intra prediction modes. This paper proposes a fast intra mode decision algorithm for real-time encoding of H.264/AVC based on the dominant edge direction (DED). The DED is extracted using pixel value summation and subtraction in the horizontal and vertical directions. By using the DED, three modes instead of nine are chosen for RDO calculation to decide on the best mode in the 4×4 luma block. For the 16×16 luma and the 8×8 chroma, only two modes are chosen instead of four. Experimental results show that the entire encoding time saving of the proposed algorithm is about 67% compared to the full intra search method with negligible loss of quality.

关键词： H 264 Intra prediction Mode decision Dominant edge direction

Formation of High-quality Advanced High-k Oxide Layers at Low Temperature by Excimer UV Lamp-assisted Photo-CVD and Sol-gel Processing

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Chemical Research in Chinese Universities 2004年第4期20卷 396-402页

作者： YU J. J. electronic & electrical Engineering University College London

We have successfully demonstrated that high quality and high dielectric constant layers can be fabricated by low temperature photo-induced or -assisted processing. Ta_2O_5 and ZrO_2 have been deposited at telectrical properties. Low leakage current densities on the order of 10 -8 A/cm 2 at 1 MV/cm for deposited ultrathin Ta_2O_5 films and ca.10 -6 A/cm 2 for the photo-CVD ZrO_2 layers and photo-irradiated sol-gel HfO_2 layers have been readily achieved. The improvement in the leakage properties of these layers is attributed to the UV-generated active oxygen species O( 1D) which strongly oxidize any suboxides to form more stoichiometric oxides on removing certain defects, oxygen vacancies and impurities present in the as-prepared layers. The photo-CVD Ta_2O_5 films deposited across 10.16-cm Si wafers exhibit a high thickness uniformity with a variation of less than \{±2.0%\} being obtained for ultrathin ca.10 nm thick films. The lamp technology can in principle be extended to larger area wafers, providing a promising low temperature route to the fabrication of a range of high quality thin films for future ULSI technology.

关键词： Excimer lamp High-kdielectrics Thin film Chemical vapour deposition(CVD) Sol-gel processing

Key design parameters and optimum method of medium- and high-velocity synchronous induction coilgun based on orthogonal experimental design

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Chinese Physics B 2019年第2期28卷 202-209页

作者： Kai-Pei Liu Xiao-Bo Niu Ya-Dong Zhang Zeng-Chao Ji Jian-Yuan Feng Wen-Qi Li School of electrical Engineering Wuhan University electronic Information School Wuhan University College of electrical and electronic Engineering Shandong University of Technology

The energy conversion efficiency of a multistage synchronous induction coilgun(MSSICG) has become one of the key factors that restricts its industrialization. To improve the launch efficiency of medium-and high-velocity MSSICG,we propose an optimization design scheme combining orthogonal experimental design(OED) and self-consistent design method in this paper. The OED is introduced to reduce the number of iterations and improve the identification accuracy and efficiency. A self-consistent design model is established to overcome a defect that the parameters that need to be optimized will multiply as the number of coil stages increases. The influence of six factors(radial thickness of armature, axial length of armature, axial length of coil, capacitance, wire diameter, and slip speed) on the launch efficiency are then evaluated by range analysis. This work presents a valuable reference for optimizing medium-and high-velocity MSSICG.

关键词： multistage synchronous induction coilgun(MSSICG) self-consistent design orthogonal experimental design(OED) range analysis

Mutator for transferring a memristor emulator into meminductive and memcapacitive circuits

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Chinese Physics B 2014年第7期23卷 366-376页

作者：于东升梁燕 Herbert H.C.Iu 胡义华 School of Information and electrical Engineering China University of Mining and Technology School of electrical Electronic and Computer EngineeringThe University of Western Australia School of electronic and electrical Engineering University of Strathclyde

In this paper, a concise but effective interface circuit for transforming a memristor into meminductive and memcapac- itive systems is designed. This newly proposed interface circuit, constructed by only two current conveyors, is equipped with three available ports, which can provide six connecting combinations in terms of one resistor, one capacitor, and one memristor. For the sake of confirming the design effectiveness, theoretical and simulation discussions are hence introduced and all the experimental waveforms provide conclusive evidence to validate the correctness of these new mutators. The most attractive features of this new interface circuit are the floating terminals and convenient practical implementation.

关键词： memristor meminductive memcapacitive self-excited oscillator

Performance comparison of zero-Schottky-barrier and doped contacts carbon nanotube transistors with strain applied

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Nano-Micro Letters 2010年第2期2卷 126-133页

作者： Md.Abdul Wahab Khairul Alam department of electrical and electronic Engineering United International University department of electrical and electronic Engineering East West University

Atomistic quantum simulation is performed to compare the performance of zero-Schottky-barrier and doped source-drain contacts carbon nanotube field effect transistors(CNTFETs) with strain applied. The doped source-drain contact CNTFETs outperform the Schottky contact devices with and without strain applied. The off-state current in both types of contact is similar with and without strain applied. This is because both types of contact offer very similar potential barrier in off-state. However, the on-state current in doped contact devices is much higher due to better modulation of on-state potential profile, and its variation with strain is sensitive to the device contact type. The on/off current ratio and the inverse subthreshold slope are better with doped source-drain contact, and their variations with strain are relatively less sensitive to the device contact type. The channel transconductance and device switching performance are much better with doped source-drain contact, and their variations with strain are sensitive to device contact type.

关键词： Zero-Schottky-barrier Doped contact Strain Inverse subthreshold slope Intrinsic cut-off frequency

Control Scheme for Distributed Generator Providing Network Voltage Support

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电力系统自动化 2012年第8期36卷 198-202页

作者： Miles A.REDFERN department of electronic and electrical Engineering University of Bath

The distributed generator over the last 30years has posed several challenges when they are connected to a distributed *** most immediate problem is to change the voltage at the connection point depending on the power supplied to the network and may cause it to exceed statutory *** paper describes a new control scheme for a distributed generator for supporting the voltage control in the network,thus ensuring the distributed generator to contribute to network voltage *** scheme performance is demonstrated by a model for a distributed generator connected to a distribution *** result shows that using the new control scheme,the distribution network voltage constraints are maintained while maximizing the active power delivered by distributed generators.

关键词：分布式网络电压控制控制计划发电机电压管理网络连接分销网络有功功率

Impact of Electric Vehicle Aggregator with communication Time Delay on Stability Regions and Stability Delay Margins in Load Frequency Control System

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Journal of Modern Power Systems and Clean Energy 2021年第3期9卷 595-601页

作者： Ausnain Naveed Sahin Sonmez Saffet Ayasun the department of electrical and electronic Engineering Nigde Omer Halisdemir UniversityNigdeTurkey the department of electrical and electronic Engineering Gazi UniversityAnkaraTurkey

This paper investigates the impact of electric vehicle(EV)aggregator with communication time delay on stability regions and stability delay margins of a single-area load frequency control(LFC)***,a graphical method characterizing stability boundary locus is *** a given time delay,the method computes all the stabilizing proportional-integral(PI)controller gains,which constitutes a stability region in the parameter space of PI ***,in order to complement the stability regions,a frequency-domain exact method is used to calculate stability delay margins for various values of PI controller *** qualitative impact of EV aggregator on both stability regions and stability delay margins is thoroughly analyzed and the results are authenticated by time-domain simulations and quasi-polynomial mapping-based root finder(QPmR)algorithm.

关键词： communication time delay electric vehicle(EV)aggregator frequency regulation proportional-integral(PI)controller design stability delay margin stability region