1998
Autores
Araujo, RE; Freitas, DS;
Publicação
IECON '98 - PROCEEDINGS OF THE 24TH ANNUAL CONFERENCE OF THE IEEE INDUSTRIAL ELECTRONICS SOCIETY, VOLS 1-4
Abstract
Simulation is a useful tool which can significantly reduce resources invested during product development. The present paper describes the development of the Vector Control Signal Processing (VCSP) blockset for use with MATLAB/Simuhnk(R). The originality of this blockset consists on the extension of Simulink for design, simulation and prototyping of signal processing algorithms in power conversion systems. The VCSP blockset, consists on a number of newly developed blocks. Together with Real-Time WorkshopTM and a number of other generally available blocks, it takes advantage of the inherent visual programming techniques of Simulink to reach the above goals. Due to its open and flexible nature, this approach is also very useful as a tool for teaching. The work is focused on modelling and simulation for power conversion systems use in the drive of rotating AC machines with vector control methods. By concept, a simulation environment can be examined at different abstraction or hierarchy levels. The approach in this paper is so the formulation of a simulation task at different levels: component level, electric circuit level, functional description and implementation description. The basic blockset functions are presented and some examples of modelling techniques for both simple and complex drive structures are included. Simulation results are presented and discussed as well.
1996
Autores
Araujo, RE; Goncalves, JJ; Tavares, A; Freitas, DS;
Publicação
MELECON '96 - 8TH MEDITERRANEAN ELECTROTECHNICAL CONFERENCE, PROCEEDINGS, VOLS I-III: INDUSTRIAL APPLICATIONS IN POWER SYSTEMS, COMPUTER SCIENCE AND TELECOMMUNICATIONS
Abstract
The phasor visualizer presented in this paper is performs real time calculation in steady-state and transient conditions of simultaneous electromagnetic torque, magnetic flux, voltages and currents of an induction motor supplied with sinusoidal voltages or through frequency converters and provide an oscillographic display. The phasor visualizer is an instrument for analysis, investigations and teaching of AC machine drives. The instruments needs no shaft position or speed sensor, it uses exclusively the acquired stator currents and voltages. The main fields of application are: element of a monitoring system, integration in a control unit, research tool for induction motor drives, and test shop. Practical results of the implementation are be presented and discussed.
2010
Autores
De Castro, R; Araujo, RE; Cardoso, JS; Freitas, D;
Publicação
2010 IEEE Vehicle Power and Propulsion Conference, VPPC 2010
Abstract
The correct estimation of the friction coefficient in automotive applications is of paramount importance in the design of effective vehicle safety systems. In this article a new parametrization for estimating the peak friction coefficient, in the tire-road interface, is presented. The proposed parametrization is based on a feedforward neural network (FFNN), trained by the Extreme Learning Machine (ELM) method. Unlike traditional learning techniques for FFNN, typically based on backpropagation and inappropriate for real time implementation, the ELM provides a learning process based on random assignment in the weights between input and the hidden layer. With this approach, the network training becomes much faster, and the unknown parameters can be identified through simple and robust regression methods, such as the Recursive Least Squares. Simulation results, obtained with the CarSim program, demonstrate a good performance of the proposed parametrization; compared with previous methods described in the literature, the proposed method reduces the estimation errors using a model with a lower number of parameters.
2011
Autores
Ferreira, RJ; Miranda, LM; Araujo, RE; Lopes, JP;
Publicação
2011 2ND IEEE PES INTERNATIONAL CONFERENCE AND EXHIBITION ON INNOVATIVE SMART GRID TECHNOLOGIES (ISGT EUROPE)
Abstract
Bidirectional and efficient on-board charger systems for electric vehicles is a challenge nowadays. This paper describes a novel power converter system that implements bidirectional flow between the grid and an electric vehicle battery, where a dual active bridge is advantageous. With a bidirectional topology and proper control all the major grid constraints, such as power quality, harmonic rejection, active and reactive power control, and others, can be easily satisfied. A hardware prototype of the power converter is built. Experimental results from this hardware prototype verify the preliminary operation and claims of the V2G power interface.
2012
Autores
Varajao, D; Araujo, RE; Moreira, C; Lopes, JP;
Publicação
38TH ANNUAL CONFERENCE ON IEEE INDUSTRIAL ELECTRONICS SOCIETY (IECON 2012)
Abstract
The Smart Vehicle-to-Grid Project at INESC TEC is currently studying the application of matrix converters to implement an isolated bidirectional AC-DC power converter using a single power conversion stage to provide a high-frequency link between the grid and vehicle. The single-stage structure and bidirectional power flow make the matrix converter an attractive solution for the charging applications of electric vehicles. A very brief overview of the matrix converter and its modulation strategy is presented, followed by detailed analysis. The power conversion system performance is investigated in terms of the switching commutation, input filter and input power factor. Simulations and experimental results of a prototype are also presented to further validate the proposed topology and operating principle.
2011
Autores
Ferreira, RJ; Araujo, RE; Pecas Lopes, JA;
Publicação
Proceedings of the 2011 3rd International Youth Conference on Energetics, IYCE 2011
Abstract
The scope of this work is to find the best approach to control advanced inverters used to connect electric vehicles to the grid. Phase-locked Loop (PLL) is a grid voltage phase detection that makes use of an orthogonal voltage to lock the grid phase. This method is suitable for both single and three phase systems, although in single-phase, because they have less information, more advanced systems are required. The easiest way to obtain the orthogonal voltage system is using a transport delay block to introduce a phase shift of 90 degrees with respect to the fundamental frequency of the grid voltage. This method is known as Synchronous Reference Frame PLL (SRF-PLL). The use of inverse Park transformation is also possible. To lower the complexity and increasing the filtering of the output signals, methods using adaptive filters are a good alternative. For this approach, the use of a second order generalized integrator (SOGI) or Adaptive Notch filter combined with PLL, Enhanced PLL (EPLL) and Quadrature PLL (QPLL), leads to satisfactory results. © 2011 INESC Coimbra.
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