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Simple digital algorithm for improved performance in a boost PFC converter operating in CCM

IET POWER ELECTRONICS 2019年第5期12卷 1102-1113页

作者： Nair, Harish Sudhakaran Narasamma, Lakshmi Indian Inst Technol Madras Dept Elect Engn Chennai Tamil Nadu India

In power factor correction (PFC) converters, achieving both good steady-state input current waveform and fast output dynamic response is a challenge. This is due to the effect of the double-line frequency ripple present in the sensed output voltage signal which tends to distort the reference current applied to the current controller, thus leading to a distorted input current waveform. Low bandwidth (BW) voltage loop designs to reduce this input current distortion make the output dynamic response very sluggish. A digital control algorithm for the estimation of the average value of the sensed output voltage is proposed in this study to achieve low total harmonic distortion input current and fast dynamic response with a higher BW voltage loop. The proposed algorithm is computationally less intensive and requires no additional sensors or circuitry. The effectiveness of the proposed control algorithm is validated through simulation and experimental tests on a 300 W boost PFC converter prototype operating in continuous conduction mode.

关键词： reference current line frequency Fasting Power factor correction Converters computer algorithms mean value current controller continuous conduction mode Dynamic response input current voltage loop output voltage

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A novel l_1/2 sparse regression method for hyperspectral unmixing

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INTERNATIONAL JOURNAL OF REMOTE SENSING 2013年第20期34卷 6983-7001页

作者： Sun, Le Wu, Zebin Xiao, Liang Liu, Jianjun Wei, Zhihui Dang, Fuxing NJUST Sch Comp Sci & Technol Nanjing Jiangsu Peoples R China NJUST Jiangsu Key Lab Spectral Imaging & Intelligent Se Nanjing Jiangsu Peoples R China Minist Land & Resources Aero Geophys Survey Remote Sensing Ctr Beijing Peoples R China

Hyperspectral unmixing (HU) is a popular tool in remotely sensed hyperspectral data interpretation, and it is used to estimate the number of reference spectra (end-members), their spectral signatures, and their fractional abundances. However, it can also be assumed that the observed image signatures can be expressed in the form of linear combinations of a large number of pure spectral signatures known in advance (e.g. spectra collected on the ground by a field spectro-radiometer, called a spectral library). Under this assumption, the solution of the fractional abundances of each spectrum can be seen as sparse, and the HU problem can be modelled as a constrained sparse regression (CSR) problem used to compute the fractional abundances in a sparse (i.e. with a small number of terms) linear mixture of spectra, selected from large libraries. In this article, we use the l(1/2) regularizer with the properties of unbiasedness and sparsity to enforce the sparsity of the fractional abundances instead of the l(0) and l(1) regularizers in CSR unmixing models, as the l(1/2) regularizer is much easier to be solved than the l(0) regularizer and has stronger sparsity than the l(1) regularizer (Xu et al. 2010). A reweighted iterative algorithm is introduced to convert the l(1/2) problem into the l(1) problem;we then use the Split Bregman iterative algorithm to solve this reweighted l(1) problem by a linear transformation. The experiments on simulated and real data both show that the l(1/2) regularized sparse regression method is effective and accurate on linear hyperspectral unmixing.

关键词： REMOTE sensing IMAGE processing REGRESSION analysis SPECTROMETRY LINEAR systems computer algorithms ITERATIVE methods (Mathematics)

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Optimal Location and Sizing of UPQC in Distribution Networks Using Differential Evolution Algorithm

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MATHEMATICAL PROBLEMS IN ENGINEERING 2012年第1期2012卷 1-20页

作者： Taher, Seyed Abbas Afsari, Seyed Ahmadreza Univ Kashan Fac Engn Dept Elect Engn Kashan *** Iran

Differential evolution (DE) algorithm is used to determine optimal location of unified power quality conditioner (UPQC) considering its size in the radial distribution systems. The problem is formulated to find the optimum location of UPQC based on an objective function (OF) defined for improving of voltage and current profiles, reducing power loss and minimizing the investment costs considering the OF's weighting factors. Hence, a steady-state model of UPQC is derived to set in forward/backward sweep load flow. Studies are performed on two IEEE 33-bus and 69-bus standard distribution networks. Accuracy was evaluated by reapplying the procedures using both genetic (GA) and immune algorithms (IA). Comparative results indicate that DE is capable of offering a nearer global optimal in minimizing the OF and reaching all the desired conditions than GA and IA.

关键词： DIFFERENTIAL evolution (computer science) computer algorithms MATHEMATICAL optimization ELECTRIC potential ELECTRIC currents GENETIC algorithms

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Hand Gesture Recognition Using Modified 1$ and Background Subtraction algorithms

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MATHEMATICAL PROBLEMS IN ENGINEERING 2015年第1期2015卷 1-8页

作者： Khaled, Hazem Sayed, Samir G. Saad, El Sayed M. Ali, Hossam Helwan Univ Dept Elect & Commun Cairo 11795 Egypt Helwan Univ Dept Comp Engn Cairo 11795 Egypt UCL Dept Elect & Elect Engn London WC1E 6BT England NTRA Egyptian Comp Emergency Readiness Team EG CERT Cairo Egypt

computers and computerized machines have tremendously penetrated all aspects of our lives. This raises the importance of Human-computer Interface (HCI). The common HCI techniques still rely on simple devices such as keyboard, mice, and joysticks, which are not enough to convoy the latest technology. Hand gesture has become one of the most important attractive alternatives to existing traditional HCI techniques. This paper proposes a new hand gesture detection system for Human-computer Interaction using real-time video streaming. This is achieved by removing the background using average background algorithm and the 1$ algorithm for hand's template matching. Then every hand gesture is translated to commands that can be used to control robot movements. The simulation results show that the proposed algorithm can achieve high detection rate and small recognition time under different light changes, scales, rotation, and background.

关键词： GESTURE SUBTRACTION (Mathematics) computer algorithms HUMAN-computer interaction JOYSTICKS STREAMING video

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Output feedback control for nonlinearly perturbed systems via cascade compensation with logic switching

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IEE PROCEEDINGS-CONTROL THEORY AND APPLICATIONS 2005年第2期152卷 188-194页

作者： Zhang, KJ Feng, CB SE Univ Res Inst Automat Nanjing 2100096 Peoples R China

A robust output feedback tracking strategy for uncertain nonlinear systems with output measurement noise is presented by using a passivity approach. The control algorithm guarantees boundedness of all the signals in the whole closed-loop system. Tracking accuracy can be reduced to a desirable bound. A simulation example is included to demonstrate effectiveness of the proposed algorithm.

关键词： Passivity tracking accuracy Output feedback series compensation Formal logic signals computer algorithms Output Feedback Control Uncertain nonlinear system Noise measurement

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Neural network controlled grid interfaced solar photovoltaic power generation

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IET POWER ELECTRONICS 2014年第3期7卷 614-626页

作者： Singh, Bhim Shahani, Dilip Tekchand Verma, Arun Kumar Indian Inst Technol Delhi Delhi 110016 India

This study deals with a NN (neural-network)-based control algorithm of a grid interfaced SPV (solar photovoltaic) generating system. The proposed grid interfaced SPV generating system utilises a NN control algorithm-based on the LMS (least mean-square), known as Adaline (adaptive linear element) to estimate reference grid currents. A DC-DC boost converter is used for achieving the maximum power point tracking between SPV and DC bus of four-leg VSC (voltage source converter) interfaced to a three-phase, four-wire distribution system. The four-leg VSC of SPV generating system is also used for the compensation of the reactive power for zero voltage regulation or for power factor correction along with load balancing, elimination of load harmonics currents and mitigation of neutral current at PCC (point of common coupling) in three-phase four-wire distribution system. The DC bus of VSC is supported by a capacitor which is fed by SPV energy through a DC-DC boost converter. A laboratory prototype of proposed grid interfaced SPV generating system is developed to validate its developed model and the NN-based control algorithm.

关键词： ELECTRIC POWER GENERATION SYSTEMS adaline three-phase four-wire Power factor correction DC bus computer algorithms Variable structure control neutral currents surface photovoltage point of common coupling maximum power point trackers Reactive power boost converters dispensing system

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Robust controller design of SGCMG driven by hollow USM

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MICROSYSTEM TECHNOLOGIES-MICRO-AND NANOSYSTEMS-INFORMATION STORAGE AND PROCESSING SYSTEMS 2016年第4期22卷 741-746页

作者： Pan, Song Zhang, Jian-Hui Huang, Wei-Qing Nanjing Univ Aeronaut & Astronaut Coll Aerosp Engn Nanjing 210016 Jiangsu Peoples R China

This work proposes a design for robust control system of a single-gimbal control moment gyro (SGCMG) driven by a hollow ultrasonic motor. Considering the nonlinear characteristic of the whole system, the fuzzy Takage-Sugeno control theory was introduced to achieve a robust control over wide range stability. Based on the proposed control theory, the parameters of feedback control of close loop were determined, and a whole system model has been build for system simulation and robust controller research. The simulation results have shown the effectiveness of the proposed control algorithm. The proposed controller was implemented on an embedded microcontroller unit through C language. On the actual system of SGCMG driven by ultrasonic motor, a sinusoidal signal speed tracking has shown that the speed error less 0.5A degrees/s and the close loop system express a good stability over a referenced speed range of 0.2-72A degrees/s. Step response experiments shown that the system fast response time without overshot. The experiments have verified the proposed robust control algorithm in speed, robustness and stability.

关键词： velocity errors control systems C language systems simulation Robust controllers Control Theory ultrasonic motors computer algorithms non-linear characteristic controller design speed range robust controller design micro-controller unit Systems modelling Robust control

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Stochastic hyperbolic random early detection controller based on probability density function estimator and particle swarm optimisation algorithm

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IET COMMUNICATIONS 2012年第6期6卷 638-648页

作者： Abharian, A. E. Khaloozadeh, H. Amjadifard, R. Islamic Azad Univ Sci & Res Branch Dept Elect Engn Tehran Iran KN Toosi Univ Technol Dept Syst & Control Tehran Iran Tarbiat Moallem Univ Fac Engn Tehran Iran

queue length variation. Yet, these conventional methods have been inefficient so far. Regarding the stochastic attributes of communication networks, AQM methods based on stochastic theory perform better in comparison with conventional AQM methods. A new stochastic AQM advances is advised for the control of queue length probability density function (PDF) for transmission control protocol (TCP). The Parzen window estimate of PDFs exploitation the kernel function is used to constitute the queue PDFs of the TCP/AQM routers. This study proposes a novel stochastic AQM algorithm called hyperbolic random early detection (PDF-HRED) as an appendage of random early detection (RED). The PDF-HRED is based on a stochastic PDF estimation, an HRED controller and particle swarm optimisation (PSO). The numerical simulation results by NS2 demonstrate that the PDF-HRED controller outperforms the existing AQM schemes with respect to performance characteristics.

关键词： STOCHASTIC analysis TCP/IP (computer network protocol) PARTICLE swarm optimization MATHEMATICAL analysis computer algorithms

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Improving reproducibility and sensitivity in identifying human proteins by shotgun proteomics

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ANALYTICAL CHEMISTRY 2004年第13期76卷 3556-3568页

作者： Resing, KA Meyer-Arendt, K Mendoza, AM Aveline-Wolf, LD Jonscher, KR Pierce, KG Old, WM Cheung, HT Russell, S Wattawa, JL Goehle, GR Knight, RD Ahn, NG Univ Colorado Dept Chem & Biochem Boulder CO 80309 USA Univ Colorado Howard Hughes Med Inst Boulder CO 80309 USA

Identifying proteins in cell extracts by shotgun proteomics involves digesting the proteins, sequencing the resulting peptides by data-dependent mass spectrometry (MS/MS), and searching protein databases to identify the proteins from which the peptides are derived. Manual analysis and direct spectral comparison reveal that scores from two commonly used search programs (Sequest and Mascot) validate less than half of potentially identifiable MS/MS spectra (class positive) from shotgun analyses of the human erythroleukemia K562 cell line. Here we demonstrate increased sensitivity and accuracy using a focused search strategy along with a peptide sequence validation script that does not rely exclusively on XCorr or Mowse scores generated by Sequest or Mascot, but uses consensus between the search programs, along with chemical properties and scores describing the nature of the fragmentation spectrum (ion score and RSP). The approach yielded 4.2% false positive and 8% false negative frequencies in peptide assignments. The protein profile is then assembled from peptide assignments using a novel peptide-centric protein nomenclature that more accurately reports protein variants that contain identical peptide sequences. An Isoform Resolver algorithm ensures that the protein count is not inflated by variants in the protein database, eliminating similar to25% of redundant proteins. Analysis of soluble proteins from a human K562 cells identified 5130 unique proteins, with similar to100 false positive protein assignments.

关键词： PROTEINS PROTEOMICS AMINO acid sequence PEPTIDES MASS spectrometry SPECTRUM analysis computer algorithms

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A new non-symmetry and anti-packing model and its application to image contrast enhancement

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computerS & ELECTRICAL ENGINEERING 2011年第5期37卷 669-680页

作者： Chen, Chuanbo Wang, Guangwei Sarem, Mudar Huazhong Univ Sci & Technol Coll Comp Sci Wuhan 430074 Peoples R China

In this paper, a non-symmetry and anti-packing image representation model (NAM) has been proposed. NAM is a hierarchical image representation method and it aims to provide faster operations and less storage requirement. By taking a rectangle sub-pattern, for example, we describe the idea of NAM and its encoding algorithm. In addition, an approach for adaptive area histogram equalization for image contrast enhancement based on a NAM image is presented. The contrast enhancement approach is designed to meet the NAM image representation and it can be duplicated with faster operation. The complexity analysis and the experimental results show that the NAM based algorithm for image contrast enhancement is faster and more effective than that based on matrix image. (C) 2011 Elsevier Ltd. All rights reserved.

关键词： IMAGE processing MATHEMATICAL models computer algorithms EQUALIZERS (Electronics) ELECTRONICS research ELECTRICAL engineering

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