The Experts below are selected from a list of 60 Experts worldwide ranked by ideXlab platform

François Lapicque - One of the best experts on this subject based on the ideXlab platform.

  • Investigation of the response of separate electrodes in a polymer electrolyte membrane fuel cell without reference electrode
    Journal of Applied Electrochemistry, 2007
    Co-Authors: Mathieu Boillot, Caroline Bonnet, Sophie Didierjean, François Lapicque
    Abstract:

    The paper presents electrochemical measurements carried out in a PEMFC with a view to determining the separate kinetics of the electrode reactions. For this purpose, the separate response of one electrode (anode or cathode) was magnified by dilution of the reacting gas, respectively hydrogen and oxygen, and comparison of the experimental data in the form of Steady Voltage-current variations and impedance spectra. Experiments were carried out at 60 °C and ambient pressure. Water management was thoroughly controlled so that the gases leaving the cell had the same relative humidity in all experiments of one series. Hydrogen oxidation, although rapid, corresponds to overpotentials up to 50 mV at high dilution rates and current densities. Assuming a Tafel–Volmer mechanism, the exchange current density of the anode reaction at the Pt surface is of the order of 1 mA cm^−2. The two techniques employed led to Tafel slopes of oxygen reduction ranging from 120 to 150 mV/decade, with an exchange current density near 1 μA cm^−2, in good agreement with published data.

Josep M Guerrero - One of the best experts on this subject based on the ideXlab platform.

  • economic power schedule and transactive energy through an intelligent centralized energy management system for a dc residential distribution system
    Energies, 2017
    Co-Authors: Jingpeng Yue, Juan C Vasquez, Josep M Guerrero
    Abstract:

    Direct current (DC) residential distribution systems (RDS) consisting of DC living homes will be a significant integral part of future green transmission. Meanwhile, the increasing number of distributed resources and intelligent devices will change the power flow between the main grid and the demand side. The utilization of distributed generation (DG) requires an economic operation, stability, and an environmentally friendly approach in the whole DC system. This paper not only presents an optimization schedule and transactive energy (TE) approach through a centralized energy management system (CEMS), but also a control approach to implement and ensure DG output Voltages to various DC buses in a DC RDS. Based on data collection, prediction and a certain objectives, the expert system in a CEMS can work out the optimization schedule, after this, the Voltage droop control for Steady Voltage is aligned with the command of the unit power schedule. In this work, a DC RDS is used as a case study to demonstrate the process, the RDS is associated with unit economic models, and a cost minimization objective is proposed that is to be achieved based on the real-time electrical price. The results show that the proposed framework and methods will help the targeted DC residential system to reduce the total cost and reach stability and efficiency.

Maurizio Porfiri - One of the best experts on this subject based on the ideXlab platform.

  • influence of electrode surface roughness and steric effects on the nonlinear electromechanical behavior of ionic polymer metal composites
    Physical Review E, 2009
    Co-Authors: Maurizio Porfiri
    Abstract:

    In this paper, we analyze the influence of electrode surface roughness and steric effects on the nonlinear electromechanical behavior of ionic polymer metal composites (IPMCs). We use the modified Poisson-Nernst-Planck equations to describe the electric potential and mobile counterion distributions within the IPMC for a Steady Voltage applied across the IPMC rough electrodes. We present an analytical solution of the nonlinear three-dimensional boundary value problem based on the method of matched asymptotic expansions. The distribution of mobile counterions within the polymer region is characterized by thin boundary layers in the proximity to the polymer-electrode interfaces, where enrichment and depletion of mobile charges take place. The presence of rough landscapes drastically increases the polymer-electrode surfaces and thereby significantly improves the overall charge storage. We determine closed-form expressions for the average bending moment produced by the IPMC and for its average stored charge and capacitance. We show that the bending moment produced by an IPMC is linearly proportional to the stored charge, which in turn increases nonlinearly as the Voltage applied across the electrodes increases. The average charge stored in the IPMC increases as the electrode surface roughness increases and decreases as steric effects become prominent.

Ahmet Serdar Yilmaz - One of the best experts on this subject based on the ideXlab platform.

  • developed analytical expression for current harmonic distortion of the pv system s inverter in relation to the solar irradiance and temperature
    Electrical Engineering, 2021
    Co-Authors: Suleyman Adak, Hasan Cangi, Bilal M Eid, Ahmet Serdar Yilmaz
    Abstract:

    This paper deals with modeling and simulation of the total harmonic distortion of the current (THDI) dispatched from the inverter and connected to nonlinear load. The change of THDI was examined in relation to the ambient temperature (T) and solar irradiance (G). The developed model is being used to extract parameters for a given THDI as a function of temperature and solar radiation. This study outlines the working principle of photovoltaic (PV) panel as well as PV array. Off-grid PV system is modeled by using Matlab/Simulink program, and detailed analytical study has been carried out in this work. The design, modeling and simulation of this study are performed from 50 up to 988 W/m2 for solar irradiance. Harmonic components have negative effects on the Steady-Voltage stability of the PV system. Therefore, analytical expression is needed for Steady-state stability analysis in order to reduce negative effects. Hence, two analytical expressions of THDI were obtained by two new different methods which are statistical package for the social sciences program and genetic expression programming. Eventually, two different methods have been verified by the Matlab/Simulink program in order to find out THDI and demonstrated the effectiveness of the proposed strategy. As a result of this study, it is observed that input current THDI of nonlinear load is too high at low irradiance. It is suggested that active harmonic filters should be used at low irradiance in order to produce better quality energy and avoid damages in the PV system.

Yilmaz, Ahmet Serdar - One of the best experts on this subject based on the ideXlab platform.

  • Developed analytical expression for current harmonic distortion of the PV system’s inverter in relation to the solar irradiance and temperature
    'Springer Science and Business Media LLC', 2020
    Co-Authors: Adak Suleyman, Cangi Hasan, Eid, Bilal M., Yilmaz, Ahmet Serdar
    Abstract:

    This paper deals with modeling and simulation of the total harmonic distortion of the current (THDI) dispatched from the inverter and connected to nonlinear load. The change of THDI was examined in relation to the ambient temperature (T) and solar irradiance (G).The developed model is being used to extract parameters for a given THDI as a function of temperature and solar radiation. This study outlines the working principle of photovoltaic (PV) panel as well as PV array. Off-grid PV system is modeled by using Matlab/Simulink program, and detailed analytical study has been carried out in this work. The design, modeling and simulation of this study are performed from 50 up to 988 W/m2 for solar irradiance. Harmonic components have negative effects on the Steady-Voltage stability of the PV system. Therefore, analytical expression is needed for Steady-state stability analysis in order to reduce negative effects. Hence, two analytical expressions of THDI were obtained by two new different methods which are statistical package for the social sciences program and genetic expression programming. Eventually, two different methods have been verified by the Matlab/Simulink program in order to find out THDI and demonstrated the effectiveness of the proposed strategy. As a result of this study, it is observed that input current THDI of nonlinear load is too high at low irradiance. It is suggested that active harmonic filters should be used at low irradiance in order to produce better quality energy and avoid damages in the PV system. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature