Abstract

Flywheel systems are attractive in hybrid and electric vehicles due to their ability to handle power during acceleration and braking. The combination of a flywheel device with a battery source has several advantages such as high peak power capacity, high energy density and reduction in the number of charge/discharge cycles of the battery. A flywheel based all-electric driveline is investigated in this thesis. The novelty of the system consists in the use of a double wound flywheel machine, which divides the system in two different power levels. Due to this configuration, the system becomes efficient and can handle the power developed during fast dynamical processes. The complete driveline consists of three main components: the battery, the flywheel machine and the wheel motor. The High-Power (HP) side of the driveline connects the flywheel machine to the wheel motor, whereas the Low-Power (LP) side connects the flywheel machine to the battery. The connections of different components of the system are made electrically through power converter devices. The present thesis focuses on the electrical converters and control strategies used in the flywheel based all-electric driveline. The control of power converters is responsible for the logic and functionality of the driveline, being a challenging step within this project. Different power converter topologies have been investigated: a DC/DC plus a DC/AC converter on the LP side, and an AC/DC/AC converter on the HP side. The design and assembly of the power electronics and their control scheme have been successfully implemented. Different control strategies have been suggested and a complete scaled driveline has been assembled and tested based on previous simulation results. Results have confirmed the functionality of the driveline, where smoothed output power has been obtained from the battery, whereas the flywheel handles power transients on the traction side. An average efficiency of about 87% (battery to wheels) has been obtained. The power converter systems have been shown to be efficient and robust, with control strategies able to handle the peak energy flow in the system. A regenerative braking strategy has been simulated and a wheel-to-wheel efficiency of about 80% has been estimated.

Abstract

International audience; This paper addresses the classical graph partitioning problem applied to the air network. We consider an air transportation network with aircraft inducing a control workload. This network has to be partitioned into K balanced sectors for which the cutting flow is minimized.

Abstract

International audience; The fast growth of air traffic that began during the 80's raises some questions about what future air traffic control (ATC) systems need to be. A major change will probably be required in Europe within a 30 year time frame. Fortunately, recent developments in air navigation systems provide new opportunities for efficient autonomous navigation. Several studies have been conducted in order to develop automation in ATC, based either on centralized or distributed systems. An important part of the ATC task is to avoid separation losses (which are called "conflicts") between aircraft. The article presents an implementation of a reactive distributed conflict resolution method on a traffic simulator providing a realistic traffic sample. The method is described, and some results regarding its efficiency and its degradation with an increase in traffic are given. In particular, a critical traffic level appears, above which efficiency drops dramatically. This level depends on the method used; the airspace itself is not saturated.

Abstract

Intelligent Transport Systems work with information and control technologies which provide the core of ITS functions. Some of these technologies, like loop detectors, are well known to transportation professionals. However, there are a number of less familiar technologies and system concepts that are the key to ITS functions. The technical core of ITS is information and control technologies, but human factors are also vitally important, and potentially very complex. This paper introduces the main ITS enabling technologies and explains why transport professionals should involve human factor experts at an early stage of design of ITS equipment and facilities. First Published Online: 27 Oct 2010 Document type: Article

Abstract

Modern society is facing great challenges due to pollution and increased carbon dioxide (CO2) emissions. As part of solving these challenges, the use of renewable energy sources and electric vehicles (EVs) is rapidly increasing. However, increased dynamics have triggered problems in balancing energy supply and consumption demand in the power systems. The resulting uncertainty and unpredictability of energy production, consumption, and management of peak loads has caused an increase in costs for energy market actors. Therefore, the means for studying the balancing of local smart grids with EVs is a starting point for this paper. The main contribution is a simulation-based approach which was developed to enable the study of the balancing of local distribution grids with EV batteries in a cost-efficient manner. The simulation-based approach is applied to enable the execution of a distributed system with the simulation of a local distribution grid, including a number of charging stations and EVs. A simulation system has been constructed to support the simulation-based approach. The evaluation has been carried out by executing the scenario related to balancing local distribution grids with EV batteries in a step-by-step manner. The evaluation results indicate that the simulation-based approach is able to facilitate the evaluation of smart grid– and EV-related communication protocols, control algorithms for charging, and functionalities of local distribution grids as part of a complex, critical cyber-physical system. In addition, the simulation system is able to incorporate advanced methods for monitoring, controlling, tracking, and modeling behavior. The simulation model of the local distribution grid can be executed with the smart control of charging and discharging powers of the EVs according to the load situation in the local distribution grid. The resulting simulation system can be applied to the study of balancing local smart grids with EV batteries. Based on the evaluation results, it is estimated that the simulation-based approach can provide an essential, safe, and cost-efficient method for the evaluation of complex, critical cyber-physical systems, such as smart grids. Document type: Article

Abstract

Simulation has become an established technique to support the design of complex, mechatronic or cyber-physical systems. Ideally, simulations should already be performed at an early design phase before high-cost design commitments are made, and the recent advances in the digitalization of design information open possibilities for automatic generation of simulation models. However, high-fidelity simulation model building depends on accurate data. In particular, firstprinciples models are desirable source information for simulations, but such models generally are not available at an early design stage. This paper investigates the automatic generation of first-principles 3D models for piping intensive systems based on design information that is available at an early design stage, namely Piping & Instrumentation Diagrams (P&ID). An algorithm is presented for the generation of such 3D models based on machine-readable P&ID information. The main focus of the algorithm is the automatic generation of feasible pipelines into the 3D models, so that the model has sufficient information which can be exploited in further work to automatically generate high fidelity first-principles thermohydraulic simulations.

Abstract

[EN] Among all the auxiliary components in conventional and electric vehicles, air-conditioning (AC) systems present the highest energy consumption. In fully electrical vehicles (FEVs), the heating of the cabin becomes an additional challenge as there is less waste heat available. Therefore, a careful design of the air-conditioning system and of the operation strategies is necessary to reach a reasonable FEV autonomy without compromising the thermal comfort. This paper presents a tool for the design, analysis and optimization of an efficient air-conditioning system for an electric minibus. It consists of dynamic models of each component of the system that have been developed and fully validated individually. Finally, they have been coupled together to simulate the overall vehicle performance of the vehicle in MATLAB-SIMULINK. The core of the system is a water-to-water reversible heat pump with a variable speed compressor. The internal water loop connects the heat pump to the air-coolers inside the cabin while the external water loop is integrated within the heat rejection system of the power electronics. An automatic control system regulates the speed of the compressor, the blowers and the circulation pumps to reach thermal comfort. The power consumption has been analysed under different working conditions and control settings using the overall vehicle model. The latter is a powerful tool not only to design and select MAC equipment, but also to find the most efficient operation strategies. This work has been supported by the European Commission under the 7th European Community framework program as part of the ICE project “MagnetoCaloric Refrigeration for Efficient Electric Air-Conditioning”, Grant Agreement no. 265434.B. Torregrosa-Jaime acknowledges the Spanish Science and Innovation Ministry (Ministerio de Ciencia e Innovación) for receiving the Research Fellowship FPU ref. AP2010-2160. Torregrosa-Jaime, B.; Payá Herreo, J.; Corberán, JM. (2013). Design of Efficient Air-Conditioning Systems for Electric Vehicles. SAE International Journal of Alternative Powertrains. 2(2):291-303. https://doi.org/10.4271/2013-01-0864 S 291 303 2 2