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43rd Annual Conference of the IEEE-Industrial-Electronics-Society (IECON)

作者： Concari, L. Barater, D. Concari, C. Toscani, A. Buticchi, G. Liserre, M. Univ Parma Parma Italy Univ Kiel Kiel Germany

ISBN: (纸本)9781538611272

This paper presents a three-phase converter architecture with a reduced common mode voltage to be used in photovoltaic power systems. The full-bridge architecture is modified by adding two additional switches in the DC path that allow decoupling the load from the source during the freewheeling phases. Optimized modulation strategies are analyzed and compared against the space vector modulation for the full-bridge. Extensive measurements show an improved efficiency when SiC devices are used, and a theoretical analysis links this efficiency to a marked extension of the converter lifetime.

关键词： Three-phase Inverters Photovoltaic H8 pulse-width modulation Space vector Common-mode voltage Leakage current

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Research on Intelligent Contactor of Distributed Wind Power System 4

Research on Intelligent Contactor of Distributed Wind Power ...

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4th International Conference on Electric Power Equipment-Switching Technology (ICEPE-ST)

作者： Cheng, Shen Cai, Zhiyuan Shenyang Univ Technol Sch Elect Engn Shenyang Liaoning Peoples R China

ISBN: (纸本)9781538616512

Aiming at the power quality problems such as voltage sag caused by grid connection of distributed generation, this paper presents a new control scheme based on Buck-Boost transform circuit. pulse width modulation control and adaptive closed-loop voltage feedback control are applied to the voltage on the contactor coil. The working principle and process of the system are introduced in detail and the validity of the design is verified. This scheme enables the contactor to realize the functions of energy-saving operation, wide operating voltage range, low voltage ride through and other characteristics. It can be widely used in distributed power system, which has good practical significance and market prospect.

关键词： Buck-Boost contactor distributed power intelligent control pulse-width modulation

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Digital Control System Design for a Cuk Converter 18

Digital Control System Design for a Cuk Converter

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18th International Conference of Young Specialists on Micro/Nanotechnologies and Electron Devices (EDM)

作者： Aksenov, Efim A. Yurkevich, Valery D. Novosibirsk State Tech Univ Automat Dept Novosibirsk Russia

ISBN: (纸本)9781509066889

Cascade control system design for a Cuk converter with pulse-width modulator in control loop is discussed. Proposed control system consists of two cascades. Inner one maintains input current by PI controller with an additional low-pass filtering. In outer one the third-order controller provides output voltage regulation. Analytical expressions are derived for digital implementation of the proposed control laws by microcontroller. Numerical simulation results are presented.

关键词： DC-DC converters pulse-width modulation PI controller digital controller singular perturbation method

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EXPERIMENTAL EVALUATION METHODOLOGY FOR SPACECRAFT PROXIMITY MANEUVERS IN A DYNAMIC ENVIRONMENT

EXPERIMENTAL EVALUATION METHODOLOGY FOR SPACECRAFT PROXIMITY...

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作者： Richard Salvatore Zappulla II NAVAL POSTGRADUATE SCHOOL

学位级别：博士

In an effort to pursue advanced space missions, improved onboard trajectory optimization and path-planning capabilities are necessary. Regardless of the mission, the paramount requirement for any candidate guidance-and-control method is the ability to react in real time to a dynamic environment, followed by fuel efficiency. Ground-based kinodynamic test beds are critical in developing, testing, and verifying these requirements. The NPS POSEIDYN test bed is introduced here as a state-of-the-art (SOTA) dynamic, hardware-in-the-loop test bed. Key improvements to the software architecture, enabling the development of multi-rate guidance, navigation, and control (GNC) algorithms, are presented in addition to a detailed system characterization. To aid in the experimental evaluation of GNC algorithms, a Standard Test Framework is proposed in addition to a new guidance comparison metric previously missing in the literature, which simultaneously captures the computational complexity and algorithm performance. Guidance and control methods representing the SOTA are experimentally evaluated and compared against a proposed rapidly exploring random tree-based guidance method using the proposed test framework and the comparison metric.

关键词： guidance control GNC real-time guidance and control hardware-in-the-loop dynamic simulator pulse-width modulation sigma-delta modulation standard test framework guidance comparison methodology guidance comparison metric dynamic environment guidance and control trade space

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Microfluidic platforms for high-throughput mammalian cell printing, transfection, and dosage-dependent studies

Microfluidic platforms for high-throughput mammalian cell pr...

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作者： Kristina Pan WOODRUFF ECOLE POLYTECHNIQUE FEDERALE DE LAUSANNE

学位级别：博士

With the advent of high-throughput and genome-wide screening initiatives, there is a need for improved methods for cell-based assays. Current approaches require expensive equipment, rely on large-scale culturing formats not suited for small or rare sample types, or involve tedious manual handling. Microfluidic systems could provide a solution to these limitations, since these assays are accessible, miniaturized, and automated. When coupled with high- content analysis, microfluidics has the potential to drastically increase throughput in cell biology and drug discovery. In light of these benefits, we developed 3 microfluidic approaches for mammalian cell-based assays: (1) printing of live mammalian cells into nanowell arrays, (2) a high-throughput transfection device, and (3) a module that generates complex, continuous concentration profiles. Our first technique generates high-density nanowell arrays of live mammalian cells (LMCAs) using a standard contact microarrayer. Both commonly used cell lines and primary cells cultured on the arrays are highly viable and maintain their signature phenotype, making the platform suitable for long-term stem cell differentiation studies. Our 675-well array is ~2.6x more dense than a 1,536-well microtiter plate and can be frozen and thawed, facilitating the handling, storage, and screening of large libraries of cells. LMCAs are also compatible with transfection, a technique that could enable analysis of the entire proteome in the natural cellular context. Transfection is routinely conducted on high- throughput arrays, but this setup requires manual cell culturing and precludes precise control over the cell environment. To this end, we created a microfluidic chip that streamlines cell loading and culturing and implements 280 independent transfections at up to 99% efficiency. The chip can perform co-transfections, in which the number of cells expressing each protein and the average protein expression level can be precisely tuned as a

关键词： microfluidics microarrays live cell printing high-throughput screening highcontent imaging automated microscopy transfection mammalian synthetic biology stem cells concentration-time profiles pulse-width modulation

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Frequency-domain coherent multidimensional spectroscopy when dephasing rivals pulsewidth: Disentangling material and instrument response

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JOURNAL OF CHEMICAL PHYSICS 2017年第8期147卷 084202-084202页

作者： Kohler, Daniel D. Thompson, Blaise J. Wright, John C. Univ Wisconsin Dept Chem 1101 Univ Ave Madison WI 53706 USA

Ultrafast spectroscopy is often collected in the mixed frequency/time domain, where pulse durations are similar to system dephasing times. In these experiments, expectations derived from the familiar driven and impulsive limits are not valid. This work simulates the mixed-domain four-wave mixing response of a model system to develop expectations for this more complex field-matter interaction. We explore frequency and delay axes. We show that these line shapes are exquisitely sensitive to excitation pulse widths and delays. Near pulse overlap, the excitation pulses induce correlations that resemble signatures of dynamic inhomogeneity. We describe these line shapes using an intuitive picture that connects to familiar field-matter expressions. We develop strategies for distinguishing pulse-induced correlations from true system inhomogeneity. These simulations provide a foundation for interpretation of ultrafast experiments in the mixed domain. Published by AIP Publishing.

关键词： SPECTRUM analysis pulse-width modulation EXCITATION spectrum PICOSECOND pulses SIMULATION methods & models

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Color mixing from monolithically integrated InGaN-based light-emitting diodes by local strain engineering

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APPLIED PHYSICS LETTERS 2017年第4期111卷 041101-041101页

作者： Chung, Kunook Sui, Jingyang Demory, Brandon Ku, Pei-Cheng Univ Michigan Dept Elect Engn & Comp Sci Ann Arbor MI 48109 USA

Additive color mixing across the visible spectrum was demonstrated from an InGaN based light-emitting diode (LED) pixel comprising red, green, and blue subpixels monolithically integrated and enabled by local strain engineering. The device was fabricated using a top-down approach on a metal-organic chemical vapor deposition-grown sample consisting of a typical LED epitaxial stack. The three color subpixels were defined in a single lithographic step. The device was characterized for its electrical properties and emission spectra under an uncooled condition, which is desirable in practical applications. The color mixing was controlled by pulse-width modulation, and the degree of color control was also characterized. Published by AIP Publishing.

关键词： LIGHT emitting diodes IMAGE color analysis INDIUM gallium nitride PIXELS pulse-width modulation

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Digital pulse-width Modulator with Asynchronous Change of Compare Register Value and Short Delay Time

Digital Pulse-Width Modulator with Asynchronous Change of Co...

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International Scientific-Technical Conference on Actual Problems of Electronics Instrument Engineering

作者： Vagiz A. Kabirov Valery D. Semyonov Nikita P. Vintonyak Danila B. Borodin Sergey S. Tyunin Tomsk State University of Control Systems and Radioelectronics Tomsk Russia

This paper presents an analysis of signal delay time in implementation of digital pulse-width modulators (DPWM). The paper demonstrates that the most essential component of delay time in a digital modulator is the time required for implementation of DPWM, and that it is almost always understood that the DPWM is a type 1 PWM. It is shown that the maximum delay time in such approach to DPWM implementation within the range cannot be less than one PWM conversion period. A new approach to DPWM implementation is proposed, suggesting an increase of the number of signal measurements within a PWM period and an asynchronous change of the compare register value in the digital comparator. Signal delay in the proposed DPWM is reduced N times, where N is the number of signal measurements within a PWM period. The proposed approach essentially results in implementation of a DPWM as a type 2 PWM.

关键词： Digital control systems for switching converters pulse-width modulation Phase frequency characteristic

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The Design of Mini-Rotary Forcespinning System for Nanofiber Synthesis

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Procedia Engineering 2017年 170卷 24-30页

作者： I. Gede Putu Agastya Eka Wiraputra Ahmad Fauzi Akmal Zulfi Muhammad Miftahul Munir Khairurrijal Department of Physics Faculty of Mathematics and Natural Science Institut Teknologi Bandung Jl Ganesa no. 10 Bandung 40132 Indonesia Research Center for Bioscience and Biotechnology Institut Teknologi Bandung Jl Ganesa no. 10 Bandung 40132 Indonesia

Recent advances in nanofiber sciences have led to its application in various fields, such as electronic equipments, industrial uses, research purposes, and medical sciences, which lead to the increasing variation of nanofiber synthesis method. A large number of products start to rely on the advancement of this field, which implies the dependence of several industies on the development of efficient synthesis devices. However, some of the methods that were established earlier possess several drawbacks which potentially outweigh the actual benefits. Therefore, to overcome the problems present in previous systems, a new method utilizing centrifugal force was developed in this research, which is called mini-Rotary Forcespinning. This method is the variant of the previous research which employed a similar machine with a larger scale. While the pre-existing instruments have been adequate to produce fibers, the control mechanism is rather complicated due to the usage of alternating current (AC). In this research, an initial design of the device, which is operable from 3000 rpm to 18000 rpm was established. Within the range, the device performed firmly with 17.4 gram weighing, which is crucial to the stability of the system as a whole. This research paper discusses the schematics and control mechanism, and the possibility of further synthesis operation is predicted.

关键词： brushless motor centrifugal force duty cycle optical switch pulse-width modulation rotation spinning weighing

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Baseband distortion compensation for high-precision power electronics using regularly sampled pulse-width modulators with sawtooth carrier

Baseband distortion compensation for high-precision power el...

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European Conference on Power Electronics and Applications

作者： B.J.D. Vermulst Eindhoven University of Technology The Netherlands

This paper presents a straight-forward method to compensate baseband distortion for regularly sampled PWMs with a sawtooth carrier, for high-precision power electronics applications such as MRI and lithography. The method is computationally lightweight, and pseudo-code is given to simplify implementation. Measurements are conducted, which show that distortion can be reduced significantly by more than 40 dB.

关键词： pulse-width modulation Harmonics Power Quality

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