Examinando por Materia "SISTEMAS HIBRIDOS"
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Artículo de Publicación PeriódicaConverging-input convergent-state and related properties of time-varying impulsive systems(2020-07-03) Mancilla-Aguilar, J. L.; Haimovich, Hernán"Very recently, it has been shown that the standard notion of stability for impulsive systems, whereby the state is ensured to approach the equilibrium only as continuous time elapses, is too weak to allow for any meaningful type of robustness in a time-varying impulsive system setting. By strengthening the notion of stability so that convergence to the equilibrium occurs not only as time elapses but also as the number of jumps increases, some facts that are well-established for time-invariant nonimpulsive systems can be recovered for impulsive systems. In this context, our contribution is to provide novel results consisting in rather mild conditions under which stability under zero input implies stability under inputs that converge to zero in some appropriate sense." Artículo de Publicación PeriódicaDesarrollo de modelos híbridos para la optimización de la gestión energética de una red eléctrica con conexión a línea de suministro, generación mediante fuentes renovables, almacenamiento y consumo(2020-06) Sabor, Mauricio Agustín; Jones Amari, Alan Aeron; De Bernardez, Leopoldo; Vilaboa, Iván"Se desarrolló un modelo híbrido para la gestión de la energía de una red eléctrica con conexión a línea de suministro, generación mediante fuentes renovables y no renovables, almacenamiento en baterías, producción de hidrógeno y consumo. El modelo permite no solamente optimizar el desempeño de la red eléctrica propuesta sino también analizar instalaciones de producción y acumulación de energía considerando la oferta y la demanda, los costos involucrados y los precios de compra y venta de energía a la red. " Artículo de Publicación PeriódicaStrong ISS implies strong iISS for time-varying impulsive systems(2020-12) Haimovich, Hernán; Mancilla-Aguilar, J. L."For time-invariant (nonimpulsive) systems, it is already well-known that the input-to-state stability (ISS) property is strictly stronger than integral input-to-state stability (iISS). Very recently, we have shown that under suitable uniform boundedness and continuity assumptions on the function defining system dynamics, ISS implies iISS also for time-varying systems. In this paper, we show that this implication remains true for impulsive systems, provided that asymptotic stability is understood in a sense stronger than usual for impulsive systems" Artículo de Publicación PeriódicaA technical, environmental and financial analysis of hybrid buses used for public transport(2018-04) Orbaiz, Pedro; Dijk, Nicolás van; Cosentino, Santiago; Oxenford, Nicolás; Carignano, Mauro G.; Nigro, Norberto M."This paper presents a technical, financial and environmental analysis of four different hybrid buses operated under Buenos Aires driving conditions. A conventional diesel bus is used as reference and three electric hybrids equipped with different energy storage technologies, Li-Ion, NiMH batteries and double layer capacitors (ultracapacitors), are evaluated, along with a hydraulic hybrid platform which uses high-pressure accumulators as its energy buffer. The operating conditions of the buses are set using real driving GPS data collected from various bus routes within the city. The different vehicle platforms are modeled on AUTONOMIE SA and validated by comparing the obtained fuel consumption results to those reported by local transport authorities and values found in the literature. The embedded energy and CO2 emissions of each platform are estimated using GREET and the total cost of ownership of each vehicle is calculated and compared to that of the conventional bus. Furthermore, aging models are proposed to evaluate the life duration of the batteries and ultracapacitors. Results show that, independent of the energy storage technology, the fuel economy performance of all hybrids is highly dependent on the size and configuration of the powertrain and energy storage components. When optimized, all hybrids achieve significant fuel consumption reductions compared to a conventional diesel bus, however, the ultracapacitor based system seems to outperform the other technologies. The battery based electric buses achieve similar fuel consumption reductions, but the NiMH based batteries shows a considerably shorter life expectancy. This has a significant impact on both the economic and environmental performance of this vehicle. The life cycle emission analysis shows that, given the high fuel consumption of a conventional bus, the additional embedded CO2 emissions of the hybrid vehicles are offseted by the achieved reduction of in-service CO2 emissions due to fuel consumption reductions. Regarding the economic performance of the different platforms, results show that the fuel savings achieved by all hybrids displace the higher capital costs required. Overall, all hybrid buses show a strong potential to reduce both CO2 emissions and costs, resulting in negative costs of CO2 abatement." Artículo de Publicación PeriódicaUniform input-to-state stability for switched and time-varying impulsive systems(2020-12) Mancilla-Aguilar, J. L.; Haimovich, Hernán"We provide a Lyapunov-function-based method for establishing different types of uniform input-to-state stability (ISS) for time-varying impulsive systems. The method generalizes to impulsive systems with inputs the well established philosophy of assessing the stability of a system by reducing the problem to that of the stability of a scalar system given by the evolution of the Lyapunov function on the system trajectories. This reduction is performed in such a way that the resulting scalar system has no inputs. Novel sufficient conditions for ISS are provided, which generalize existing results for time-invariant and time-varying, switched and nonswitched, impulsive and nonimpulsive systems in several directions." Artículo de Publicación PeriódicaUniform stability of nonlinear time-varying impulsive systems with eventually uniformly bounded impulse frequency(2020-11) Mancilla-Aguilar, J. L.; Haimovich, Hernán; Feketa, Petro"We provide novel sufficient conditions for stability of nonlinear and time-varying impulsive systems. These conditions generalize, extend, and strengthen many existing results. Different types of input-to-state stability (ISS), as well as zero-input global uniform asymptotic stability (0-GUAS), are covered by employing a two-measure framework and considering stability of both weak (decay depends only on elapsed time) and strong (decay depends on elapsed time and the number of impulses) flavors. By contrast to many existing results, the stability state bounds imposed are uniform with respect to initial time and also with respect to classes of impulse-time sequences where the impulse frequency is eventually uniformly bounded. We show that the considered classes of impulse-time sequences are substantially broader than other previously considered classes, such as those having fixed or (reverse) average dwell times, or impulse frequency achieving uniform convergence to a limit (superior or inferior). Moreover, our sufficient conditions are stronger, less conservative and more widely applicable than many existing results."