检索结果-内蒙古大学图书馆

A PWM based readout circuit for optical sensors with adaptive frequency control

IEICE ELECTRONICS EXPRESS 2018年第16期15卷 20180613-20180613页

作者： Park, Kangyeob Oh, Won-Seok Korea Elect Technol Inst SoC Platform Res Ctr 25 Saenari Ro Seongnam Si 13509 Gyeonggi Do South Korea

This paper proposes a pulse-width modulation-based readout circuit for optical sensors which adopts adaptive frequency control technique to enhance input dynamic range of current sensing systems. The proposed readout circuit is designed and fabricated using a 65 nm CMOS process. The readout IC achieves 100 dB of dynamic range in current sensing system by adaptively controlling the frequency of operating clock.

关键词： pulse-width modulation current to PWM converter optical sensor photodiode trans-impedance amplifier CMOS

来源：评论

学校读者我要写书评

暂无评论

New Hybrid pulse-width modulation Technique to Reduce Current Distortion and Extend Current Reconstruction Range for Three-Phase Inverter using only DC-link Sensor

New Hybrid Pulse-Width Modulation Technique to Reduce Curren...

引用

IET International Conference on Power Electronics, Machines and Drives

作者： Yen-Shin Lai Yong-Kai Lin Chih-Wei Chen Center for Power Electronics Technology National Taipei University of Technology

ISBN: (纸本)9781622761456

The paper proposes a new modulation technique which can reduce the current distortion and extend the current reconstruction range for three-phase inverter using only DC-link sensor. The proposed PWM technique is a hybrid method which consists of space vector modulation method and the PWM method without using null switching states. The former provides low current distortion, however it is with narrower current reconstruction range. In contrast, the later extends the current reconstruction range at the cost of higher current distortion. For the proposed method, in the measurable region of space vector modulation method, space vector modulation is used to reduce the current distortion. Moreover, as the modulation range is out of that measurable region, the PWM method without using null switching states is applied to extend the current re-construction range. Furthermore, the current reconstruction limitation using only DC-link sensor is analyzed. The analysis shows that reduction of PWM switching frequency and acquisition time can extend the current re-construction range. Comparison of experimental results derived from an FPGA-based controlled inverter is included. It will be demonstrated that using the proposed hybrid PWM technique the three-phase current signals of inverter can be reconstructed even under very low modulation index range while providing low current harmonic distortion of inverter output.

关键词： pulse-width modulation Inverter Total Harmonic Distortion

来源：评论

学校读者我要写书评

暂无评论

Influence of pulse width on luminous efficiency for a two-degree field

引用

LIGHTING RESEARCH & TECHNOLOGY 2017年第3期49卷 357-369页

作者： Fan, S. Zhang, X. Gu, X. Shen, H. Liu, M. Fudan Univ Dept Light Sources & Illuminating Engn Room 100Handan Rd 220 Yangpu Dist Shanghai 200433 Peoples R China

A two-degree bipartite field was used to investigate the influence of pulse width on human luminous perception. The frequency of the pulsed light was 100Hz and the duty ratio was set to 1, 2, 5, 10, 20, 30, 50 and 70%. The results show that pulsed light has a brightness enhancement effect and that the enhancement effect changes when the wavelength and duty ratio are different. The maximum enhancement effect appears at 430nm and the minimum at 460nm. Then, a theoretical spectral luminous function for pulsed light as a function of wavelength and duty ratio was calculated using cone fundamentals. The newly established luminous function can be used to calculate the real brightness perceived by human eyes when people are exposed to a space illuminated by pulse-width modulation dimming lamps.

关键词： LIGHTING design LUMINOSITY pulse-width modulation BRIGHTNESS perception BRIGHTNESS (Optics)

来源：评论

学校读者我要写书评

暂无评论

Nonlinear electromechanical modelling and dynamical behavior analysis of a satellite reaction wheel

引用

ACTA ASTRONAUTICA 2017年 141卷 143-157页

作者： Aghalari, Alireza Shahravi, Morteza Maleke Ashtar Univ Technol Dept Aerosp Engn Tehran Iran

The present research addresses the satellite reaction wheel (RW) nonlinear electromechanical coupling dynamics including dynamic eccentricity of brushless dc (BLDC) motor and gyroscopic effects, as well as dry friction of shaft-bearing joints (relative small slip) and bearing friction. In contrast to other studies, the rotational velocity of the flywheel is considered to be controllable, so it is possible to study the reaction wheel dynamical behavior in acceleration stages. The RW is modeled as a three-phases BLDC motor as well as flywheel with imbalances on a rigid shaft and flexible bearings. Improved Lagrangian dynamics for electromechanical systems is used to obtain the mathematical model of the system. The developed model can properly describe electromechanical nonlinear coupled dynamical behavior of the satellite RW. Numerical simulations show the effectiveness of the presented approach.

关键词： Reaction wheel Nonlinear dynamic Electro-mechanical effect Energy method pulse-width modulation

来源：评论

学校读者我要写书评

暂无评论

pulse-width predictive control for LTV systems with application to spacecraft rendezvous

引用

CONTROL ENGINEERING PRACTICE 2017年 60卷 199-210页

作者： Vazquez, R. Gavilan, F. Camacho, E. F. Univ Seville Escuela Super Ingenieros Dept Ingn Aeroespacial Camino Descubrimientos S-N Seville 41092 Spain Univ Seville Escuela Super Ingenieros Dept Ingn Sistemas & Automat Camino Descubrimientos S-N Seville 41092 Spain

This work presents a Model Predictive Controller (MPC) that is able to handle Linear Time-Varying (LTV) plants with pulse-width Modulated (PWM) control. The MPC is based on a planner that employs a pulse Amplitude Modulated (PAM) or impulsive approximation as a hot-start and then uses explicit linearization around successive PWM solutions for rapidly improving the solution by means of quadratic programming. As an example, the problem of rendezvous of spacecraft for eccentric target orbits is considered. The problem is modeled by the LTV Tschauner Hempel equations, whose state transition matrix is explicit;this is exploited by the algorithm for rapid convergence. The efficacy of the method is shown in a simulation study. (C) 2016 Elsevier Ltd. All rights reserved.

关键词： Spacecraft autonomy Space robotics pulse-width modulation Trajectory planning Optimal trajectory Linear time-varying systems

来源：评论

学校读者我要写书评

暂无评论

A White LED Boost IC for Backlight of TFTLCD Based on a Current-Limited pulse-width modulation

A White LED Boost IC for Backlight of TFTLCD Based on a Curr...

引用

54th IEEE International Midwest Symposium on Circuits and Systems (MWSCAS)

作者： Sung, Guo-Ming Lu, You-Hsiang Taipei Univ Technol Dept Elect Engn Taipei Taiwan

ISBN: (纸本)9781612848570

This paper presents a boost DC-to-DC switching converter which is implemented with current-limited pulse width modulation (PWM) to drive various white LEDs in the backlight of TFTLCD. The proposed white LED boost IC consists of the bandgap reference, error amplifier, hysteresis comparator, linear ramp generator, voltage-to-current converter and driving buffer which are designed and implemented with a standard 0.35-mu m 2P4M CMOS technology. Notify that the proposed bandgap reference can provide a reference voltage and a reference current, simultaneously. Besides, the white LED boost IC can eliminate sub-harmonic oscillation using a slope-compensation technique. Simulation results show that the output voltage, output current, output voltage ripple and output current ripple are 18 V, 20 mA, 5.98 mV and 41.8 mu A, respectively, at a power supply of 3.3 V. The proposed white LED boost IC can drive five white LEDs with a power efficiency of 85% and a chip area of 0.89x0.92 mm(2).

关键词： 2P4M CMOS technology CMOS integrated circuits CMOS integrated circuits CMOS technology Clocks DC-DC power convertors LED displays Light emitting diodes Low earth orbit satellites Manganese PWM power convertors Switching circuits TFTLCD amplifiers backlight bandgap reference boost DC-to-DC switching converter comparators (circuits) current 20 mA current 41.8 muA current-limited PWM driving buffer efficiency 85 percent error amplifier hysteresis comparator linear ramp generator liquid crystal displays pulse-width modulation reference current reference voltage size 0.35 mum size 0.89 mm size 0.92 mm slope-compensation technique subharmonic oscillation switching convertors voltage 18 V voltage 3.3 V voltage 5.98 mV voltage-to-current converter white LED boost IC

来源：评论

学校读者我要写书评

暂无评论

Three-Electrode Metal-Oxide Gas Sensor System With CMOS Interface IC

引用

IEEE SENSORS JOURNAL 2017年第3期17卷 784-793页

作者： Park, Jeong-Ho Park, Kwang-Min Kim, Tae-Wan Shin, Seongheon Park, Chong-Ook Yoo, Hyung-Joun Korea Adv Inst Sci & Technol Sch Elect Engn Daejeon 34141 South Korea Mobile Sensor & IT Convergence Ctr Daejeon 305701 South Korea Korea Adv Inst Sci & Technol Dept Mat Sci & Engn Daejeon 34141 South Korea

This paper proposes a system with CMOS interface IC for three-electrode metal-oxide gas sensor. The proposed system adopts a switching scheme using pulsewidth modulation signals in order to control the temperature of the heater and measure the resistance of the sensor simultaneously in actual. Furthermore, the switching method can solve the electrical asymmetry issue of the sensor. Wide variation in the resistance of the sensor is covered by the mode-adjustable integrator. The proposed system achieves temperature control up to 250 degrees C, and detectable resistance range of the sensing material from 80 Omega to 2 M Omega with relative error of less than 1.5%.

关键词： Electrical resistance measurement gas detectors gas sensor pulse-width modulation resistance heating temperature measurement three-electrode gas sensor

来源：评论

学校读者我要写书评

暂无评论

Shunt Active Power Filter Based on Cascaded Transformers Coupled With Three-Phase Bridge Converters

引用

IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS 2017年第5期53卷 4673-4681页

作者： de Almeida Carlos, Gregory Arthur Jacobina, Cursino Brandao Ramos Agra Mello, Joao Paulo dos Santos, Euzeli Cipriano, Jr. Univ Fed Campina Grande PPgEE COPELE Postgrad Program Elect Engn BR-58429900 Campina Grande PB Brazil Fed Inst Alagoas Dept Control & Ind Proc BR-57608180 Palmeira Dos Indios AL Brazil Univ Fed Campina Grande Dept Elect Engn BR-58429900 Campina Grande PB Brazil Indiana Univ Purdue Univ Dept Elect & Comp Engn Indianapolis IN 46202 USA

This paper proposes a multilevel shunt active power filter (SAPF) to deal with either harmonic current compensation or reactive power compensation. Such a device can reduce the harmonic distortion at the grid currents provided by nonlinear loads located in stiff systems. The proposed SAPF is based on three-phase bridge converters connected to cascaded single-phase transformers. The transformer arrangement permits the compensator to use a single dc-link unit, which simplifies the control strategy and the number of sensors. The multilevel waveforms are generated by using a suitable pulse-width modulation (PWM) strategy associated with the transformer turns ratio. Modularity and simple maintenance make the proposed SAPF an attractive solution compared with some conventional configurations. The model, the PWM technique, and the control strategy are presented, as well as studies considering harmonic distortion and semiconductor losses estimation. Simulation and experimental results are presented in order to validate theoretical approaches.

关键词： Cascaded transformers multilevel converters pulse-width modulation shunt active power filter

来源：评论

学校读者我要写书评

暂无评论

A broad review on desulfation of lead-acid battery for electric hybrid vehicle

引用

MICROSYSTEM TECHNOLOGIES-MICRO-AND NANOSYSTEMS-INFORMATION STORAGE AND PROCESSING SYSTEMS 2017年第6期23卷 2263-2273页

作者： Singh, Anupama Karandikar, P. B. MIT Dept IEEE Pune Maharashtra India Army Inst Technol Dept Elect Engn Pune Maharashtra India

In today's world, electric hybrid vehicle (EHV) is a prevailing vehicle technology in that the major part is electric battery and lead-acid battery is the widely usable battery in the EHV because of its cost and efficiency. The real disadvantage in lead-acid battery is that it easily sulfates because of improper charging or discharging. Hence, desulfation circuit or charge controller is placed along with the rechargeable lead-acid battery for proper charging and subsequently sulfating gets reduced. Numerous research techniques are proposed for this desulfation or charge controlling are inspected in this paper. The desulfation or charge controlling of lead-acid batteries done based upon various techniques and our audit made according to various methods such as pulse width modulation, pressure feedback, resonant frequency, chemical reaction and artificial intelligent. Eventually, the direction for the future research is talked about in view of the survey investigation.

关键词： LEAD-acid batteries HYBRID electric vehicles ELECTRIC charge & distribution pulse-width modulation ELECTRIC batteries

来源：评论

学校读者我要写书评

暂无评论

Three-phase battery storage system with transformerless cascaded multilevel inverter for distribution grid applications

引用

IET RENEWABLE POWER GENERATION 2017年第6期11卷 742-749页

作者： Curi Busarello, Tiago Davi Mortezaei, Ali Bubshait, Abdullah S. Simoes, Marcelo Godoy Univ Fed Santa Catarina Rua Pomerode 710 Blumenau Brazil Colorado Sch Mines Dept EECS 1812 Illinois St Golden CO 80401 USA

A distributed generator (DG) based on renewable energy is a promising technology for the future of the electrical sector. DGs may benefit utility companies and customers in a variety of perspectives. However, DGs suffer from intermittent behaviour. Storage systems appear as an attractive solution to support the continuous operation of DGs. The technology within the storage also plays an important role, since DGs and storage are connected in medium-voltage grids. The use of batteries and the DC/AC converter in its conventional structure presents drawbacks in such grids. In this context, this study presents a three-phase transformerless battery storage system (BSS) based on a cascaded H-bridge inverter applied to a medium-voltage grid. The BSS is composed of eight equal series connected H-bridge converters, without bulk transformers, for connection to a distribution grid. Each converter contains 75, 12V/600Ah lead-acid batteries. The converters are controlled through pulse-width modulation at 600Hz. The BSS is able to keep working even with a failure of one of its converters. Reactive energy compensation not compensated by an existent passive filter is also performed. A case study with simulated and experimental results obtained through a hardware-in-the-loop system is presented showing the efficacy of the proposed BSS.

关键词： battery storage plants PWM invertors distributed power generation power grids PWM power convertors lead acid batteries compensation transformerless cascaded H-bridge multilevel inverter distribution grid application distributed generator DG renewable energy power loss reduction energy bill reduction DC-AC converter three-phase transformerless battery storage system BSS series connected H-bridge converter medium-voltage utility grid lead-acid battery pulse-width modulation reactive energy compensation passive filter hardware-in-the-loop system voltage 12 V frequency 600 Hz

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：