Abstract
In this article, we propose a linear parameterization (LP) for representing the friction in the tire-road interface, suitable for on-line Identification. This model was obtained by employing function approximation techniques, which results in an optimization problem to minimize the fitting error between the LP and the nonlinear Burckhardt model. Compared with others LPs proposed in the literature, the optimal LP features a reduced number of parameters and good approximation capabilities. Moreover, the proposed model can be identified though linear Identification techniques, simplifying the on-line peak friction estimation. Simulation results obtained with a vehicle simulator demonstrates the effectiveness of the proposed parameterization. © 2011 IFAC.

Abstract
In this paper, a detailed description of a control architecture for managing the DC link control of EVs with multiple energy sources is presented. The proposed topology allows the control of the power flow among supercapacitors and batteries, while ensuring the regulation of the DC link voltage, thanks to a cascade of voltage and current linear controllers. A simple analytical study is provided to illustrate the tuning guidelines for the current and voltage, based on proportional + integral controllers. A prototype system has been designed and built in reduced scale hardware to analyze the performance of the proposed control system. The experimental results are in accordance with the simulations and demonstrated the effectiveness of the proposed control technique. © 2011 IEEE.

Abstract
This article is concerned with the design of an energy management system (EMS) for the hybridization of multiple energy sources (ES's) in electric vehicles, focusing in a particular configuration composed by batteries and supercapacitors (SCs). As a first design step, we investigated an (non-causal) optimal power allocation, targeting the minimization of the energy losses over a complete driving cycle. Albeit the solution obtained with this formulation demands the advance knowledge of the vehicle driving cycle, it also provides a useful benchmark solution to assess the performance of causal EMS's. A more practical EMS is then derived, based on the control allocation (CA) concept. This approach, typically employed in redundant control systems, enable us to address the various objectives and constraints that appear in EMS design problem, such as the DC bus voltage regulation, SC state of charge tracking, minimization of power losses, current and state of charge limits, etc. Simulation results show the effectiveness of the proposed CA based EMS, yielding performances very close to the optimal non-causal power allocation. © 2011 IEEE.

Abstract
In the last years we have witnessed a growing interest, by the academic community and the automotive industry, in the multi-motor electric vehicles. The electrical nature of the propulsion is going to stress even more an increasing insertion of electronic devices in the vehicles. Furthermore, carmakers are performing research and already presented some vehicles based on the concept of X-By-Wire. Consequently, the growing complexity of the actuators and their control, as well as the need of increasing the safety and reliability of the vehicles obliges to the study and development of intelligent computational systems dedicated to the detection and diagnosis of failures in the electric propulsion. Hence, it is fundamental to start advanced studies leading to the development of innovative solutions that embed fault-tolerant electric propulsion in the electric vehicles. Accordingly, the main objective of this work consists on the bibliographic revision and study of fault-tolerant diagnosis and control systems dedicated to multi-motor electric vehicles.

Abstract
The economical and environment impacts of fossil energies increased the interest for hybrid, battery and fuel-cell electric vehicles. Energy management systems (EMS) have a fundamental role in achieving high efficiency levels in vehicle performances, without compromise its drivability features. This is a complex task, since one is dealing with the integration of different physical subsystems. In addition, several vehicle electric power-train architectures must be considered, requiring different energy management approaches. Considering EMS for real-time applications will bring a higher complexity level. This paper aims at putting these efforts into perspective deriving a more holistic view of the literature in this topic. We start the analysis on the general requirements for EMS to identify the more demanding ones for real-time applications. Based on this analysis, we suggest some open challenges and describe new research opportunities. © 2011 INESC Coimbra.

Abstract
Electrical Power Quality represents a challenging as much as attracting research topic nowadays, with consequences to all economic areas. Here, we studied the alternatives for reactive compensation in a residential low-voltage distribution grid using the Alternative Transient Program (ATP-EMTP). We developed a simulation model based on the results obtained from field measurements in a low voltage residential distribution grid with non-linear loads. We employed capacitors in different strategic places throughout the grid and changed their configurations, aiming to evaluate the technical viability of the application of reactive compensation. In this way, we investigated a methodology for the optimization of reactive compensation in secondary distribution grids, based on different solutions, in order to improve the voltage profile throughout the grid, as well as the technical losses that occur in a grid of this type. Next, we compared the simulated results with the field measurements. This analysis revealed that both approaches produced similar results, validating the simulation model. We therefore conclude that this model effectively reproduces the real linear and non-linear loads of the residential distribution grid and is suitable to be used in future studies. © 2011 IEEE.