Modelling a PEM fuel cell stack with a nonlinear equivalent circuit

A nonlinear circuit model of a polymer electrolyte membrane (PEM) fuel cell stack is presented. The model allows the simulation of both steady-state and dynamic behaviour of the stack on condition that the values of some of its parameters are changed in the two operating conditions. The circuit parameters can be obtained by means of simple experimental tests and calculations. The PEM stack is modeled as seen from the power conditioning system side, without requiring parameters necessary for complex mathematical models and not easily obtainable by the majority of users. A procedure of parameter determination is developed and a comparison between the simulated and experimental results for both steady-state and dynamic behaviour of the PEM stack is shown

Prediction of low-frequency electromagnetic interferences from SMPS

This paper investigates the low-frequency electromagnetic interference (EMI) from switched-mode power supplies (SMPS) by electromagnetic field coupling. The interferences are calculated by means of equivalent circuits that represent the weak magnetic and electric field coupling between the EMI sources of a SMPS and a reference victim circuit. The inductive and capacitive parameters of the equivalent circuits are calculated by simple analytical formulas using suitable criteria for determining the corresponding dimensions of the EMI source circuits. The models are applied to a SMPS well predicting the noise voltage measured by a triple loop antenna (TLA)

Low-frequency analysis of electromagnetic interference from SMPS

The electromagnetic field coupling at low frequency between electromagnetic interference (EMI) sources of switched-mode power supplies (SMPS) and a victim circuit is represented by two-port networks. The mutual impedance between source and victim circuit is calculated by the induced EMF method. The two-port representation of the field coupling allows the noise voltage on a circuit victim to be predicted. As a reference victim circuit circular loops outside the source are considered. The approach is applied to a SMPS and validated through experimental measurements

Review of simple electromagnetic models for predicting radiated emissions from PCBs

This paper reviews the basic mechanisms through which voltage and current signals in printed circuit boards (PCBs) produce unwanted radiated emissions and some analytical models that can be used to predict these radiated emissions. Three models are applied to a simple PCB and the results are compared to those obtained with the electromagnetic analysis carried out with a Finite-Difference Time- Domain (FDTD) computer code. Although the models are not likely applicable to real-life problems, the comparison is useful to underline their assumptions and limitations

Analysis of design solutions for a GTEM cell

Gigahertz Transverse Electromagnetic (GTEM) cells are among the standard environments used for radiated emission and immunity tests on electrical and electronic equipment and systems at frequencies from DC up to over 1 GHz. In this paper, an analysis of different cross sections for a GTEM cel is presented. The aim of this work is to find possible new shapes for GTEM cells suitable to obtain a more uniform electric field distribution inside an unloaded cell

Caratterizzazione elettrica di sorgenti alternative per la produzione di energia elettrica

Viene descritta l'attività di ricerca riguardante la caratterizzazione elettrica di sorgenti alternative per la produzione di energia elettrica e lo studio di sistemi per l'interfacciamento di dette sorgenti con utenze in isola o con la rete. Sono stati studiati i modelli circuitali di alcuni tipi di celle fotovoltaiche allo scopo di ottenere risultati numerici confrontabili con misure sperimentali. Sono state studiate, sempre con l'intento di ricavarne modelli circuitali equivalenti, diverse tipologie di celle a combustibile. È stato sviluppato e messo a punto un modello circuitale non lineare della cella PEM, che consente di rappresentarne il comportamento a regime e dinamico. Tale circuito può essere impiegato nella simulazione di sistemi più complessi, come ad esempio sistemi di trazione elettrica, o di alimentazione di utenze in isola o distribuita. Il modello, di tipo analitico-empirico, non richiede la conoscenza di parametri di difficile individuazione, quali porosità, diffusività, coefficienti di trasferimento di carica, necessari invece per l’implementazione di modelli matematici complessi. I parametri del circuito equivalente proposto sono invece ottenibili mediante semplici prove di laboratorio, in quanto l’obiettivo della caratterizzazione è modellare la cella PEM dal lato del sistema di condizionamento della potenza

Review of simple electromagnetic models for predicting radiated emissions from PCBs

This paper reviews the basic mechanisms through which voltage and currents signals in printed circuit boards (PCBs) produce unwanted radiated emissions and some analytical models that can be used to predict these radiated emissions. Three models are applied to a simple PCB and the results are compared to those obtained with the electromagnetic analysis carried out with a Finite-Difference Time-Domain (FDTD) computer code. Although the models are not likely applicable to real-life problems, the comparison is useful to underline their assumptions and limitations

Accoppiamenti elettromagnetici all'interno di contenitori metallici risonanti

Viene descritto un metodo per la previsione degli accoppiamenti elettromagnetici all'interno di contenitori metallici risonanti. Il metodo si basa sull'analogia tra una guida d'onda rettangolare e una linea di trasmissione. Per determinare le impedenze di radiazione dei monopoli/dipoli elettrici e dei dipoli magnetici, necessarie per calcolare l'accoppiamento tra gli stessi, sono stati sviluppati modelli circuitali empirici funzione dei parametri geometrici delle stesse antenne elementari. I modelli circuitali sono stati validati sperimentalmente. L'accoppiamento tra un'antenna elementare e un modo di propagazione TE/TM nel contenitore metallico avviene mediante capacità e/o induttanze mutue e viene rappresentato mediante generatori pilotati; la sezione della linea di trasmissione tra la sorgente e la vittima viene modellata come un doppio bipolo

Nonlinear circuit model of a polymer electrolyte membrane fuel cell

A nonlinear circuit model of a polymer electrolyte membrane (PEM) fuel cell stack is presented. The model considers the time dimension, allowing the simulation of both steady-state and dynamic behaviour of the stack. The circuit parameters can be obtained by means of simple experimental tests and calculations. The PEM stack is modeled as seen from the power conditioning system side, without requiring parameters necessary for complex mathematical models and not easily obtainable by the majority of users. A procedure of parameter determination is developed and a comparison between the simulated and experimental results for both steady-state and dynamic behaviour of the PEM stack is shown

Non linear ciruit model of a polymer electrolyte membrane fuel cell

A nonlinear circuit model of a polymer electrolyte membrane (PEM) fuel cell stack is presented. The model considers the time dimension, allowing the simulation of both steady-state and dynamic behaviour of the stack. The circuit parameters can be obtained by means of simple experimental tests and calculations. The PEM stack is modeled as seen from the power conditioning system side, without requiring parameters necessary for complex mathematical models and not easily obtainable by the majority of users. A procedure of parameter determination is developed and a comparison between the simulated and experimental results for both steady-state and dynamic behaviour of the PEM stack is shown