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  • An open hardware electronic controller for motorized rotary injection valves used in Flow Injection Analysis
    Publication . Mozo, J. D.; Otero, J. I.; Durán, E.; Semião, Jorge
    This work presents the design, development and the implementation of a motorized injection valve used in Flow Injection Analysis. The built prototype has been developed based on the open hardware emergent philosophy, software and firmware, thus helping the development of a free and independent science. This policy creates a platform of open projects that feed each other, contributing to scientific and technological development while sharing knowledge. The proposed design project can be modified to implant it in other devices or projects according to the needs of each one. Also, the open project can be a great help as teaching material in Universities, since open hardware projects are fully described and documented.
  • A Zeta-CSC converter combination for single-input and bipolar output
    Publication . Litran, S. P.; Duran, E.; Ferrera, M. B.; Semiao, J.; Barroso, R. S.
    This paper presents a DC-DC converter of one input and one bipolar output. The converter has been obtained from the combination of two basic converters of one input and one output. Thus, the proposed configuration is the result of the combination of a CSC (Canonical Switching Cell) converter and a Zeta converter. A common feature of these converters is they have the same conversion relation. The input stage formed by the switching device and an inductance is shared by both converters. On the other hand, the output of the CSC converter is inverted with respect to its input and the output of Zeta converter is non-inverted, so this combination results in a bipolar type output. With the proposed topology it is possible to reduce the number of components and eliminate the need for synchronization of several switching devices. The converter has been analyzed in a steady state and the most significant operating equations have been deduced. A simulation platform has been developed in the MATLAB-Simulink, which has allowed the behavior of the converter to be verified.
  • A distributed load scheduling mechanism for micro grids
    Publication . Monteiro, J. M.; Eduardo, J.; Cardoso, Pedro J. S.; Semiao, J.
    Several protocols have recently been defined for smart grids that enable the communication between electric devices and energy management systems. While these protocols and architectures can already be applied in different fields of micro grids, it is still not clear how the distributed resources and constraints of such electrical grids can be managed in an optimum way. In order to achieve a reduction in electricity costs and maximizing investments made in renewable sources, an optimization mechanism should be used to perform load scheduling, considering different variables such as forecasted power generation curve from renewable sources, different tariffs' rates, electric circuit constraints, user restrictions and correspondent comfort levels. Given these considerations, this work defines and evaluates a distributed micro grid resource management architecture and protocol which is able to optimize load scheduling while considering all the mentioned restrictions and parameters. The proposed architecture was implemented on a multi-agent simulator and the performed tests show that significant reductions in electricity cost can be achieved using this methodology. © 2014 IEEE.