Cookies Policy
The website need some cookies and similar means to function. If you permit us, we will use those means to collect data on your visits for aggregated statistics to improve our service. Find out More
Accept Reject
  • Menu
Publications

Publications by CPES

2013

Fault-Tolerant Control Using Sliding Mode Techniques Applied to Multi-Motor Electric Vehicle

Authors
Almeida, S; Araujo, RE;

Publication
39TH ANNUAL CONFERENCE OF THE IEEE INDUSTRIAL ELECTRONICS SOCIETY (IECON 2013)

Abstract
This paper proposes the concepts of sliding mode schemes for fault tolerant control. The theoretical ideas developed in the paper were applied to a multi-motor electric vehicle (EV). To address this problem, we started by revisiting the modeling of vehicle dynamics focusing on nonlinear single-track model. The vehicle response to external perturbation forces, which are generated by unbalanced right and left traction forces due to malfunctions in motor drive, is described using the transfer functions analysis. The designing of a sliding mode controller for handling faults is described. The proposed scheme shows that certain motor drive failures can be handled directly without reconfiguring the controller. Simulation results obtained with CarSim vehicle model show the effectiveness of the fault tolerant control in various driving scenarios.

2013

Evaluation of Applicability of System Inversion to Fault Detection and Isolation on Switched Power Converters

Authors
Pinheiro, V; Araujo, RE;

Publication
2013 2ND INTERNATIONAL CONFERENCE ON CONTROL AND FAULT-TOLERANT SYSTEMS (SYSTOL)

Abstract
Fault detection has been an open problem in power converters for several years. In this paper, we aim at detecting faults by means of left invertibility techniques. Using a mathematical model of the power converter it is possible to exploit the principle of injectivity of I/O map, which allows the recovery of unknown inputs applied to the system from the measure of the outputs. To achieve this end, we utilize the existing current and voltage sensors of the converter without the need for any additional sensors. Finally, a case-study of a multiport converter is presented and simulated to illustrate the methodology. Experimental results obtained under realistic conditions illustrate the effectiveness of the scheme and prove that fault detection based on the inverse method is possible.

2013

A comparative study between causal and non-causal algorithms for the energy management of hybrid storage systems

Authors
Pinto, C; De Castro, R; Araujo, RE;

Publication
2013 15th European Conference on Power Electronics and Applications, EPE 2013

Abstract
This paper presents a comparative study between two non-causal algorithms for the energy management problem of electric vehicles, endowed with batteries and supercapacitors(SCs). Toward that goal, an optimization-based energy problem is formulated, which targets the minimization of the source's energy losses throughout a given driving cycle. This problem is solved, firstly, with the help of a fast (but locally optimal) non-linear programming solver; and, secondly, with a slow, but globally optimal, dynamic programming (DP) approach. Simulation results will demonstrate that, despite the different theoretical properties associated with these two solver approaches, both generate similar solutions. In the second part of the work, we will develop a filter-based energy management algorithm, i.e., employ batteries to provide the low-frequency content of the power demand, while SCs cover the high-frequency demand. Our approach builds on the idea of adapting the filter's time constant throughout the vehicle's journey, using, for that purpose, a fuzzy logic algorithm and the information of the state of the vehicle. In comparison with the traditional fixed time-constant approach, the simulation results show that under some conditions the adaptive time-constant algorithm has the potential to reduce the energy losses of the sources by up to 62%. © 2013 IEEE.

2013

Automatic Decomposition of Safety Integrity Levels: Optimization by Tabu Search

Authors
Azevedo, LS; Parker, D; Walker, M; Papadopoulos, Y; Araujo, RE;

Publication
SAFECOMP 2013 - Workshop CARS (2nd Workshop on Critical Automotive applications : Robustness & Safety) of the 32nd International Conference on Computer Safety, Reliability and Security, Toulouse, France, 2013

Abstract

2013

Multidimensional scaling analysis of electricity market prices

Authors
Azevedo, F; Machado, JT;

Publication
Intelligent Systems, Control and Automation: Science and Engineering

Abstract
This paper studies the impact of energy and stock markets upon electricity markets using Multidimensional Scaling (MDS). Historical values from major energy, stock and electricity markets are adopted. To analyze the data several graphs produced by MDS are presented and discussed. This method is useful to have a deeper insight into the behavior and the correlation of the markets. The results may also guide the construction models, helping electricity markets agents hedging against Market Clearing Price (MCP) volatility and, simultaneously, to achieve better financial results. © 2013, Springer Science+Business Media Dordrecht.

2013

Optimization Design in Wind Farm Distribution Network

Authors
Cerveira, A; Baptista, J; Solteiro Pires, EJ;

Publication
International Joint Conference SOCO'13-CISIS'13-ICEUTE'13 - Salamanca, Spain, September 11th-13th, 2013 Proceedings

Abstract
Nowadays, wind energy has an important role in the challenges of clean energy supply. It is the fastest growing energy source with a increasing annual rate of 20%. This scenario motivate the development of an optimization design tool to find optimal layout for wind farms. This paper proposes a mathematical model to find the best electrical interconnection configuration of the wind farm turbines and the substation. The goal is to minimize the installation costs, that include cable cost and cable installation costs, considering technical constraints. This problem corresponds to a capacitated minimum spanning tree with additional constraints. The methodology proposed is applied in a real case study and the results are compared with the ground solution. © Springer International Publishing Switzerland 2014.

  • 202
  • 317