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Development of a Medium Voltage, high Power, high frequency Four-Port Solid State Transformer

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CES Transactions on Electrical Machines and Systems 2022年第1期6卷 95-104页

作者： Ahmad El Shafei Saban Ozdemir Necmi Altin Garry Jean-Pierre Adel Nasiri IEEE Department of Electrical Engineering University of Wisconsin Milwaukee Department of Electrical-Electronic Engineering Faculty of TechnologyUniversity of Gazi Department of Electrical Engineering University of South Carolina

The power and voltage levels of renewable energy resources is growing with the evolution of the power electronics and switching module *** that,the need for the development of a compact and highly efficient solid-state transformer is becoming a critical task in-order to integrate the current AC grid with the new renewable energy *** objective of this paper is to present the design,implementation,and testing of a compact multi-port solid-state transformer for microgrid integration *** proposed system has a four-port transformer and four converters connected to the *** transformer has four windings integrated on a single common ***,it can integrate different renewable energy resources and energy storage *** port has a rated power of 25 kW,and the switching frequency is pushed to 50 k *** ports are chosen to represent a realistic industrial microgrid model consisting of grid,energy storage system,photovoltaic system,and *** grid port is designed to operate at 4.16 k VAC corresponding to 7.2 kV DC bus voltage,while the other three ports operate at 500 ***,the grid,energy storage and photovoltaic ports are active ports with dual active bridge topologies,while the load port is a passive port with full bridge rectifier *** proposed design is first validated with simulation results,and then the proposed transformer is implemented and *** results show that the designed system is suitable for 4.16 k VAC medium voltage grid integration.

关键词： Co-simulation high frequency high power medium voltage microgrid Multi-port solid state transformer

high frequency forcing on nonlinear systems

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Chinese Physics B 2013年第3期22卷 209-218页

作者：姚成贵何志威占萌 Department of Mathematics Shaoxing University Wuhan Center for Magnetic Resonance State Key Laboratory of Magnetic Resonance and Atomic and Molecular PhysicsWuhan Institute of Physics and MathematicsChinese Academy of Sciences University of the Chinese Academy of Sciences

high-frequency signals are pervasive in many science and engineering *** this work,the effect of high-frequency driving on general nonlinear systems is investigated,and an effective equation for slow motion is derived by extending the inertial approximation for the direct separation of fast and slow *** on this theory,a high-frequency force can induce various phase transitions of a system by changing its amplitude and *** simulations on several nonlinear oscillator systems show a very good agreement with the theoretic *** findings may shed light on our understanding of the dynamics of nonlinear systems subject to a periodic force.

关键词： high frequency nonlinear oscillator inertial approximation phase transitions

high frequency performance of nano-scale ultra-thin-body Schottky-barrier n-MOSFETs

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Science China(Information Sciences) 2011年第8期54卷 1756-1761页

作者： DU Gang,LIU XiaoYan & HAN RuQi Institute of Microelectronics,Peking University,Beijing 100871,China Institute of Microelectronics Peking University

The high frequency performances of nano-scale ultra-thin-body (UTB) Schottky-barrier n-MOSFETs (SB-nMOSFETs) are investigated using 2D full-band self-consistent ensemble Monte Carlo method. The UTB SB-nMOSFET devices offer excellent RF performance with high values of f T and f *** significant dependence of f T and f max on gate voltage and weak dependence on barrier height are ***,the significant dependence of g m and g ds on both gate voltage and SB height are shown. Moreover,the scalability of f T is outstanding and close to the ideal case (f T ∝ 1/L2g ). The high frequency performances of 45 nm channel length SB-nMOSFETs at ballistic transport limit are also investigated. Results show that scattering strongly affects the capacitances C gs,C gd and C *** ballistic transport limit the f T and f max are almost 10 times *** Scattering effects in nano-scale SB-nMOSFETs cannot be neglected.

关键词： Monte Carlo ultra thin body (UTB) Schottky-barrier MOSFETs (SB-MOSFETs) high frequency

A review of high frequency resonant DC-DC power converters:Topologies and planar magnetic technologies

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Science China(Technological Sciences) 2020年第8期63卷 1335-1347页

作者： XU DianGuo GUAN YueShi WANG YiJie WANG Wei School of Electrical Engineering and Automation Harbin Institute of TechnologyHarbin 150001China

With the development of high frequency resonant DC-DC power converters,the system efficiency,power density and dynamic characteristics have been significantly *** frequency resonant DC-DC converters have been applied in DC grid,renewable energy,transportation,aerospace,point-of-load(POL)power supply and many other *** high switching frequencies,switching loss and magnetic loss are the main concerns;thus,the resonant topology and planar magnetic are two key technologies to reduce *** review compares different resonant topologies and analyzes the advantages and disadvantages respectively,such as LLC circuit,dual active bridge(DAB)circuit,and other high order resonant *** planar magnetic components,optimal winding structures,modeling methods and integration methods are thoroughly *** corresponding topics,the opportunities and challenges in the future development are summarized,which mainly focus on the characteristics of wide bandgap devices,such as the dynamic resistance,output capacitance loss and also the integrated *** review can be a helpful guidance when designing high frequency resonant DC-DC converters.

关键词： high frequency resonant DC-DC power converter planar magnetic components

Dispersive behavior of high frequency Rayleigh waves propagating on an elastic half space

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Acta Mechanica Sinica 2021年第4期37卷 562-569,I0001页

作者： Ning Jia Zhilong Peng Jianjun Li Yin Yao Shaohua Chen Institute of Advanced Structure Technology Beijing Institute of TechnologyBeijing 100081China Beijing Key Laboratory of Lightweight Multi-Functional Composite Materials and Structures Beijing Institute of TechnologyBeijing 100081China School of Mechanical and Electrical Engineering Central South UniversityChangsha 410083China

When the wavelength of Rayleigh wave is comparable with nanometers,Rayleigh wave will become *** an interesting phenomenon cannot be predicted by the classical theory of *** order to reveal the internal mechanism and influencing factors of the dispersion,a model of Rayleigh wave propagating on an elastic half space is established and analyzed by a new theory of surface elastodynamics,in which the surface effect characterized by both the surface energy density and surface inertia is *** intrinsic nano-length scales,including the ratio of bulk surface energy density to bulk shear modulus and the ratio of surface mass density to bulk mass density,are *** is found that when the wavelength of Rayleigh wave is comparable with the two intrinsic nano-lengths,the surface effect becomes *** a result,dispersion of Rayleigh wave happens and even two Rayleigh waves with different wave speeds may ***,it is found that the effect of surface energy density would enhance the wave speed,while that of surface inertia would reduce *** the increase of wavelength,both effects gradually disappear and the Rayleigh wave speed degenerates to the classical *** results of this paper are not only helpful to understand the dispersive mechanism of elastic waves,but also helpful for the fine design and measurement of nanowave devices.

关键词： Rayleigh wave high frequency Dispersion Elastodynamics Surface effect

Gate-structure optimization for high frequency power AlGaN/GaN HEMTs

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Journal of Semiconductors 2010年第5期31卷 51-54页

作者：王东方袁婷婷魏珂陈晓娟刘新宇 Institute of Microelectronics Chinese Academy of Sciences Graduated University of the Chinese Academy of Sciences

The influence of gate-head and gate-source-spacing on the performance of AlGaN/GaN HEMTs was studied. Suggestions are then made to improve the performance of high frequency power AlGaN/GaN HEMTs by optimizing the *** the field-plate length can effectively enhance gain,current gain cutoff frequency and maximum frequency of *** reducing the field-plate length,devices with 0.35μm gate length have exhibited a current gain cutoff frequency of 30 GHz and a maximum frequency of oscillation of 80 *** maximum frequency of oscillation can be further optimized either by increasing the gate-metal thickness,or by using aτ-shape gate （the gate where the gate-head tends to the source side）.Reducing the gate-source spacing can enhance the maximum drain-current and breakdown voltage,which is beneficial in enhancing the maximum output power of AlGaN/GaN HEMTs.

关键词： AlGaN/GaN HEMT high frequency gate structure power

Flocking of multi-agent system with high frequency feedback robust control

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The Journal of China Universities of Posts and Telecommunications 2019年第4期26卷 43-50页

作者： Zhang Qing Wang Jie Yang Zhengquan Chen Zengqiang College of Science Civil Aviation University of ChinaTianjin 300300China Department of Automation Nankai UniversityTianjin 300071China

Flocking of multi-agent system with high-frequency feedback robust control is put forward in *** controller that has high-frequency feedback robust control is designed;it is proved that the velocity error is bounded and no collision occurs between the multi-agent under the action of the high-frequency feedback robust control by employing the boundedness theorem and the Lyapunov stability *** of multi-agent system can be formed under the action of the high-frequency feedback robust *** of multi-agent system with high-frequency feedback robust control is realized in numerical *** with the state diagram and velocity error diagram of the original flocking of multi-agent system in the simulation,flocking of multi-agent system with high-frequency feedback robust control has better stability.

关键词： flocking multi-agent system high frequency robust control

high frequency behaviours and Mssbauer study of field annealed FeCuNbSiB alloy ribbons

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Chinese Physics B 2010年第9期19卷 570-575页

作者：马小明李志伟位建强王涛李发伸 Institute of Applied Magnetics Key Laboratory for Magnetism and Magnetic Materials of the Ministry of EducationLanzhou University

This paper investigates the high frequency behaviours and magnetic anisotropy of rapidly solidified FINEMET （***3Cul） alloy ribbons annealed in an applied magnetic field. It finds that the ribbons annealed with the applied magnetic field show much higher resonance frequencies and have even higher permeability at higher frequencies than the samples annealed without the magnetic field and the non-annealed ribbons. MSssbauer spectroscopy had been employed to study the spatial distribution of the magnetic moments of five selected FINEMET alloy ribbons in different heat-treated conditions. The results show that an easy plane has been established after annealling in the magnetic field, while for the other ribbons this effect is not significant. Hence, the relationship between magnetic field annealing and high frequency property has been bridged by the bianisotropic theory.

关键词： FINEMET field annealing MSssbauer spectrum high frequency

Composition of high frequency ambient noise from cross-correlation:A case study using a small aperture array

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Earthquake Science 2010年第5期23卷 433-438页

作者： Weitao Wang Sidao Ni Baoshan Wang Institute of Geophysics China Earthquake Administration Beijing 100081 China Mengcheng National Geophysical Observatory School of Earth and Space Science University of Science and Technology of China Hefei 230026 China

Long-time cross correlation of ambient noise has been proved as a powerful tool to extract Green＇s function between two receivers. The study of composition of ambient noise is important for a better understanding of this method. Previous studies confirm that ambient noise in the long period （3 s and longer） mostly consists of surface wave, and 0.25-2.5 s noise consists more of body waves. In this paper, we perform cross correlation processing at much higher frequency （30-70 Hz） using ambient noise recorded by a small aperture array. No surface waves emerge from noise correlation function （NCF）, but weak P waves emerge. The absence of surface wave in NCF is not due to high attenuation since surface waves are strong from active source, therefore probably the high ambient noise mostly consists of body wave and lacks surface wave. Origin of such high frequency body waves in ambient noise remains to be studied.

关键词： ambient noise cross correlation Green's function body wave high frequency