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Circuits and Systems (CWCAS), 2012 IEEE 4th Colombian Workshop on

Date 1-2 Nov. 2012

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Displaying Results 1 - 25 of 32
  • [Front cover]

    Publication Year: 2012 , Page(s): 1
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  • [Copyright notice]

    Publication Year: 2012 , Page(s): 1
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    Freely Available from IEEE
  • A robust controller for DC-DC buck converters based on GZAD strategy

    Publication Year: 2012 , Page(s): 1 - 5
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (410 KB) |  | HTML iconHTML  

    This paper reports an extended version of GZAD technique for controlling DC-DC power converters with completely uncertain, but bounded time-varying loads. GZAD technique has been recently proposed as generalized version of Zero Average Dynamics strategy (ZAD) for controlling DC-DC buck power converter with known and fixed loads. However several application require control schemes for unknown and time-varying loads. In this work it is proposed to extend the GZAD strategy to control the buck converter, with unknown and time-varying loads using a nonlinear state observer. This paper numerically demonstrates high performance of the system when time-varying loads are estimated by nonlinear state observer. View full abstract»

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  • A very compact CMOS class AB current mirror for low voltage applications

    Publication Year: 2012 , Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (325 KB) |  | HTML iconHTML  

    This paper presents a compact bidirectional current mirror suitable for low voltage applications. The idea is to use complementary transistors in subthreshold which are able to set a reduced bias current through the mirror. The circuit presents a class AB operation with a THD near to 1% at 1MHz. The bandwidth is above 10MHz as shown by simulations using Spectre with 0.5μm CMOS technology parameters. View full abstract»

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  • Beekeeping monitoring module

    Publication Year: 2012 , Page(s): 1 - 6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1045 KB)  

    This paper presents the development of a module to monitor the general state inside of an artificial beehive. The physical variables that directly affect the health and production of the population were identified with its optimal ranges to stand surety for the stability of the bees. This document illustrates why the selected sensors to read these variables were chosen, how the information is acquired and how it is processed to be presented to the final user. Finally, all the elements of the module were successfully tested. All the events were registered in a text file, transferred to a pen drive and displayed over a liquid crystal display (LCD). View full abstract»

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  • Concepts, standards and communication technologies in smart grid

    Publication Year: 2012 , Page(s): 1 - 6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (386 KB)  

    Smart Grid (SG) is the current trend of the power grids in all the world, it will provide more robustness, efficiency, security, reliability, flexibility and quality of service than the current grids that have a lot of time without significant changes in their infrastructure. SG lets self-healing, modern bidirectional communications, more interaction of the users who can decide and know about their energy consume, remote monitoring of electrical variables, it facilitates the distributed energy generation, the use of renewable energy resources, modern control technologies and it will foster the development of new storage systems of energy and information, for these reasons it needs more risk assessment systems. This paper reviews the state of the art related with SG and it describes some developed standards, the wired and wireless communication systems used in the grid and the characteristics of different technologies in the Home Area Network (HAN), Neighborhood Area Network (NAN) and Wide Area Network (WAN) like ZigBee, WiFi and Broadband over Power Line (BPL). Also, it describes the challenges and initiatives in SG in the world, the concept of advanced metering infrastructure, the impacts in the components in the power systems, some software models for SGs, the potential advantages and the barriers to implement a SG, and it makes a comparison with the traditional power grid. View full abstract»

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  • Description and comparison of non-smooth bifurcations in a ramp-controlled and sine-controlled buck converter

    Publication Year: 2012 , Page(s): 1 - 6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (942 KB) |  | HTML iconHTML  

    Different types of non-smooth bifurcations have been defined in order to describe clearly the complex behaviors present in a DC-DC buck converter. According to this, a PWM - controlled buck converter is investigated with the classic ramp as T-periodic signal but also with a sine as T-periodic signal; all in order to analyze and compare the systems dynamic studying the bifurcational behavior once the non-smooth ramp signal is changed by the smooth sine signal. Finally, bifurcation diagrams from both systems show that non-smooth bifurcations appear no matter what kind of T-periodic signal is used. View full abstract»

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  • Design and implementation of a Lunabot using NASA Systems Engineering

    Publication Year: 2012 , Page(s): 1 - 6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (326 KB) |  | HTML iconHTML  

    This paper presents the design, construction and validation process of a Lunar Excavation Prototype (Lunabot) according to the NASA Systems Engineering. The systems engineering approach applied in NASA's projects, proposes an organization through phases to ensure a successful product, solving a stated engineering problem. The program formulation is composed of several phases where the general goal is to list all the requirements of the project, from the technical specifications to the budget for his development. This approach was used by Robocol Team to participate on the Third NASA Lunabotics Mining Competition. View full abstract»

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  • Design and implementation of a system for travel in form of convoy of mobile platforms Lego Mindstorms nxt 2.0

    Publication Year: 2012 , Page(s): 1 - 6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (661 KB)  

    This article explains the development of a cooperative robotic system, using three mobile platforms Lego Mindstorms nxt 2.0 as a convoy moving through an established route. These robots have actuators that allow the displacement, measurement of their environment and transmission an infrared signal that allows them to establish a wireless communication according to the orders assigned by the first device that acts as the master of the system. The development of mobile robotic systems today is very important due the interaction and integration of many devices that act to perform a task, sometimes it's necessary to develop cooperation between multiple robotic agents for working together, which improves performance a system. View full abstract»

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  • Design method of the perturb and observe controller parameters for photovoltaic applications

    Publication Year: 2012 , Page(s): 1 - 6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (346 KB) |  | HTML iconHTML  

    This paper presents an analysis of the Perturb and Observe Maximum Power Point Tracking controller, providing a useful tool to design an optimal MPPT controller for photovoltaic applications. The method uses the complete equation for the photovoltaic module to calculate exact values in the non-linear power-voltage profile. The amplitude of the duty cycle perturbation is designed from the maximum power losses restriction and the sampling time of the algorithm is designed to track a dynamic irradiance profile with three-point behavior. Finally, simulations are used to validate the proposed methodology and to demonstrate the effectiveness of the solution. View full abstract»

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  • Design of back telemetry system on CMOS ON SEMI C5 mixed-signal technology

    Publication Year: 2012 , Page(s): 1 - 5
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (480 KB) |  | HTML iconHTML  

    This paper presents design of a back telemetry system on CMOS ON - SEMI C5 mixed-signal technology. The designed system uses a different schema in order to improve the amount of information sent from the internal unit to the external unit using an alternative scheme without a load modulation strategy. The presented topology has a nontraditional architecture based on a 915 MHz voltage-controlled oscillator LC Cross-Coupled Differential. The designed system has a power consumption of 31.98mW and it represents a 6.5% of total area of 1.5 mm × 1.5 mm chip. The system was validated and simulated through Mentor Graphics IC Nanometer Electronic design automation (EDA) toolkit. View full abstract»

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  • Digital control of a single-phase boost rectifier with power factor correction using a dsPIC

    Publication Year: 2012 , Page(s): 1 - 7
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (12613 KB) |  | HTML iconHTML  

    A digital implementation of a boost rectifier with power factor correction (PFC) is presented. The proposed control involves a current control loop and a voltage control loop. The current control loop is implemented with two different methods: (a) linear compensation; and (b) ON-OFF control. The voltage control loop is implemented with a proportional-integral (PI) controller. Several Simulink/MATLAB simulations of the converter operating with both current control methods are presented. An assessment of the total harmonic distortion (THD) measurements shows the advantages of the simple ON-OFF controller. Finally, experimental results obtained from a 100W prototype using a low-cost 16-bit microcontroller are included and discussed. View full abstract»

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  • Dynamic model validation via error indexes

    Publication Year: 2012 , Page(s): 1 - 6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1058 KB) |  | HTML iconHTML  

    An error index to support the validation stage of dynamic models is proposed in this paper. The result of the index quantifies the percentage of the relative difference between an experimental signal and an estimated signal. The index is calculated for several test signals, which are selected and designed to exhibit controlled differences in contrast with a reference signal. Also, other seven indexes are calculated and compared with the proposed one. The results of the proposed index are the same controlled differences in the test signals, allowing an accurate interpretation of the results in a validation stage of a dynamic model. Additionally, experimental data taken from an excitation system for a synchronous generator are used to evaluate and validate the proposed index. View full abstract»

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  • Efficient systolic architecture for Hermitian eigenvalue problem

    Publication Year: 2012 , Page(s): 1 - 6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (462 KB) |  | HTML iconHTML  

    This paper presents an efficient systolic architecture for solving the Hermitian eigenvalue problem, which is a common issue in the spectrum sensing function of cognitive radio systems like WRANs. The designed architecture uses a novel upper triangular structure to improve performance with respect to the BLV array. The processing elements are based on sequential CORDIC processors to perform two complex Jacobi rotations. Tests and results show that the proposed architecture is suitable to design the spectrum sensing function of cognitive radio systems. The systolic architecture was described using generic structural VHDL and tested using an Altera FPGA. View full abstract»

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  • Revisión bibliográfica: Implementación del vector de park para la detección de fallas en máquinas rotativas

    Publication Year: 2012 , Page(s): 1 - 6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (417 KB)  

    In this paper we present a literature review, techniques for fault detection in induction motor stator on three-phase using the spatial vector. We focus on these techniques because it allows to verify the extent of the failure and its class, with the advantage of using non-invasive techniques that allow us to check the status of an engine without the aggravation of having to take out it of service. We especially like that the progress in the last decade, using the technique of Park's vector and the geometric characteristics of the vector for detect the fault and size of the fault. View full abstract»

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  • Indoor localization prototype using ZigBee

    Publication Year: 2012 , Page(s): 1 - 7
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1023 KB)  

    This paper presents the design and results of a localization prototype indoor based on ZigBee technology, which is capable of finding two-dimensional position of a moving object, using empirical propagation models as well as an algorithm spherical trilateration, it was possible to calculate coordinates of the system in order to develop a graphical interface in Matlab to allow log, track and monitoring the position of mobile node. (Full paper is written in Spanish). View full abstract»

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  • Integración de gestores de aprendizaje y contenidos Web en la enseñanza de los sistemas digitales: Integrating learning and Web-Content Management Systems on digital systems teaching

    Publication Year: 2012 , Page(s): 1 - 6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (428 KB)  

    Blended learning was strengthened in education in recent years, because of the technological trends and developments in the Information and Communications Technology ICT. Some software platforms are required for the learning places virtualization. These platforms must be consistent with teaching models, which are suggested from each field. Experiential teaching on engineering is important and involves experiential labs, simulations and verifications between others methodological topics. This paper proposes a software platform for virtual labs in courses of digital systems. This Web tool comprises a Content Management System (CMS), a Learning Management System (LMS), two linked databases and Web 2.0 services. This tool also supports java scripts to include a communication with a hardware platform for remote experimentation. View full abstract»

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  • Mathematical model of total cross-tied photovoltaic arrays in mismatching conditions

    Publication Year: 2012 , Page(s): 1 - 6
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (319 KB) |  | HTML iconHTML  

    This paper presents a mathematical procedure for modeling rectangular (N rows with M modules each) and non-rectangular photovoltaic (PV) arrays in Total Cross-Tied (TCT) configuration operating in uniform and mismatching conditions. The proposed model uses the simple single diode representation for each PV module; then each row of the TCT array is represented as an equivalent non-linear PV circuit with a bypass diode, which allows to represent the TCT array as one string of equivalent PV circuits. The inflection voltages (array voltages that turn off the bypass diodes) of the string are calculated in order to solve only the non-linear equation system related to the active equivalent PV circuits for calculating the array current for a given voltage. Such a strategy reduces the computational burden and improves calculation speed. A TCT array of 4×2 with deep mismatching conditions was implemented in PSIM software to validate the proposed model, obtaining a correlation between model predicted data and the circuital simulation. The accuracy and improved calculation speed of the proposed model allow its use altogether with reconfiguration techniques as well as to reduce the time of energetic evaluations of TCT arrays for PV planning. View full abstract»

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  • Methodology for the implementation of a SIMULATOR of electric transients on FPGA

    Publication Year: 2012 , Page(s): 1 - 6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (871 KB) |  | HTML iconHTML  

    This article describes the implementation of a real time electric circuit simulator prototype on a reconfigurable device. Real time measurement are presented and validated through specialized software. The proposed architecture relies on particular hardware techniques, such as parallel design, looking to satisfy the requirements of computation time. View full abstract»

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  • Modelamiento del comportamiento tèrmico de sistemas VLSI. Modeling of thermal behavior of VLSI systems

    Publication Year: 2012 , Page(s): 1 - 6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (572 KB)  

    This paper presents mathematical modelling and simulation of the thermal behavior in VLSI (Very Large Scale Integration) circuits. The mathematical model is based on the formulation of Heat Transfer equation and is discretized by finite difference method. The algorithm developed in Matlab® implements a computational model of a thermal transfer on substrate of VLSI circuit with arbitrary function and dimensions. Results are presented in a series of 3D images for different times of VLSI circuit. 3D images show temperature in z axis, dimensions in (x, y) axis and 2D images show temperature in color scale, dimensions in (x, y) axis. Last, this work present a relation between real time of simulation and the equivalent time of circuit's work. View full abstract»

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  • Modular development of a single phase multilevel converter

    Publication Year: 2012 , Page(s): 1 - 6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (474 KB) |  | HTML iconHTML  

    This paper presents the design and implementation of a modular single phase multilevel inverter using the asymmetric cascade multilevel converter type. The converter output allows 7, 15 and 31 levels and use the step modulation strategy. The selective harmonic elimination (SHE) technique was used for the computation of the firing angles. All the results were simulated in MATLAB professional software and validated by the implementation of the converter, evaluating the performance using the total harmonic distortion factor (THD). View full abstract»

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  • Multiband filters with elliptical and Gaussian dielectric resonators planar in microwave

    Publication Year: 2012 , Page(s): 1 - 6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (825 KB) |  | HTML iconHTML  

    This work describes the results of computational simulations of elliptical and Gaussian dielectric resonators excited synchronous coupled microstrip transmission line and coplanar waveguide (CPW) for the design of microwave filters in RF communications systems. By means of the equation of optics, the dimensions of materials that fill the dielectric resonators have been found. A value computational calculus of scattering S11 and S21 of elliptical and Gaussian dielectric coupled resonators is made and the possible uses in microwave filters are discussed. View full abstract»

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  • Nonlinear model predictive control for a Ball&Beam

    Publication Year: 2012 , Page(s): 1 - 5
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (453 KB) |  | HTML iconHTML  

    This article presents the development of a modelbased predictive control (MPC) for Ball & Beam system and results achieved in the implementation of this controller on a real plant. The purpose of this work is to show that the MPC is one of the optimal control strategies more employed in the research community over the last years due to good management of the nonlinearities and the fulfillment of mechanical and electrical constraints. The validation of the results is supported by comparing experimental data with theoretical results. View full abstract»

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  • Parameter calculation of a small wind turbine model cálculo de parámetros del modelo de una turbina eólica (160 w)

    Publication Year: 2012 , Page(s): 1 - 6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1517 KB)  

    A method to estimate the model parameters of a small wind turbine is proposed in this paper. The method highlights an experiment in which the wind speed, the generator angular speed and the real power consuming by the load are registered. A fifth order polynomial to represent the ratio between the power coefficient and the tip speed ratio is obtained from the registered data. The proposed method does not require a wind tunnel and can be carried out in the location of the wind generator. View full abstract»

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  • Rapid prototyping of chaotic generators using LabView-FPGA

    Publication Year: 2012 , Page(s): 1 - 6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1054 KB) |  | HTML iconHTML  

    In this paper, the development of a rapid prototyping system for chaotic generators using LabVIEW-FPGA is described. This system was envisioned as an essential tool for testing and evaluation of applications based on chaos theory such as encryption algorithms or chaos controllers. Production of a new chip realization involves design, simulation, development and evaluation phases. LabVIEW FPGA environment is well suited for creating systems very quickly. Two discrete-time chaotic generators are used to illustrate the rapid prototyping system. The paper also shows how LabVIEW code can be reused to implement coupled chaotic generators. The laboratory results are compared and verified using MATLAB simulations. Differences between experimental and simulated bifurcation diagrams are discussed. View full abstract»

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