EPE Association: EPE 2001 - Topic 11a: EMC

EPE 2001 - Topic 11a: EMC
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2001 - Conference > EPE 2001 - Topic 11: SYSTEMS ENGINEERING > EPE 2001 - Topic 11a: EMC

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   Analysis of Mis-operation Caused by EMI in Power Electronic Equipment
By Dehong Liu; Jianguo Jiang; Zhengming Zhao [View]
[Download]

Abstract: Mis-operation caused by EMI in power electronic equipment is a troublesome problem that often occurs during design and operation process. This paper is mainly focused on EMI sources, propagation characteristics, and suppression schemes in power electronic equipment. As an example, disturbances in the control circuit of a 6kW charger with a mis-operation fault are measured. The EMI caused by switching device IGBT in the main circuit and driving pulses in the control circuit are compared. Then by a system function approach, the high pass characteristic of EMI coupling path from the main circuit to the control circuit board is analyzed. Using the system function, EMI in the control circuit caused by the IGBT is predicted. To diagnose the mis-operation in the control circuit, susceptibilities of several digital logic integrated circuits(ICs) to pulse like EMI, and suppression schemes are studied through experiments. As a result, mis-operation in the control circuit of the charger is eliminated.

   Bearing current pulse rate in standard PWM drives.
By A. Kempski; R. Strzelecki; R. Smoleñski; J. Bojarski; M. Klytta [View]
[Download]

Abstract: This paper examines AC motor bearing currents (Electric Discharge Machining – EDM) resulting from a common mode (CM) voltage in a drives fed by PWM voltage source inverters. Subject literature of the problem of bearing currents has been primarily concerned with theoretical analysis of bearing current phenomena and possible mechanisms for bearing damage [1-4]. It has been rarely related to the quantitative results of the bearing currents appearance. However, it is a reasonable assumption that an amplitude and the number of EDM current pulses in a duty cycle are the most important rate–determining factors of premature bearing damage. In this paper we present the experimental results of the distribution of an amplitude and a rate of bearing current pulses. Parameters of the distribution have been also determined. They can be the basis of comparative analysis of influence of the CM current mitigation methods on the risk of electrically induced bearing damage. Especially, we focus on the improved systems with a CM choke and a CM transformer and an active filter for the CM voltage cancellation.

   Characterization of the field radiated by a magnetic component
By J. Lorange; B. Cogitore; T. Creuzet; J-P. Keradec; J-L. Schanen; C. Brun [View]
[Download]

Abstract: The presented work aims to characterize the magnetic field produced by magnetic components up to 50 cm far and 10 MHz. To sum up all the practical results by less than 15 parameters, we use limited multipole expansion together with related spherical harmonic functions. Measurement of loop antenna voltage needs special care because it often is in the µV range. In this paper we describe our theoretical approach and the measurement bench which has been built. To end, we present some preliminary results regarding a current loop.

   Common Mode EMI prediction for three-phase inverter
By D. González; J. Balcells; J. Gago; M. Lamich [View]
[Download]

Abstract: In this paper a simplified mathematical model for the prediction of the conducted EMI generated by a three-phase inverter is presented. The model allows the prediction of disturbances that propagates to the DC bus and to the load, but special attention has been paid to the Common Mode (CM) current disturbances at the load side. The model, that is based on the frequency domain, identifies the source of disturbance and its propagation paths as well. The model is used to study an undesired effect that take place in the induction motor drives: the circulation of CM currents through the motor. These currents are the origin of many problems well described on the literature and many solutions have been proposed to fix the problem. In this paper, two different vector modulation techniques are used: the Classical Space Vector Modulation (CSVM) and the CM Reduction Space Vector Modulation (CMRSVM). The experimental results obtained from the experimental plant has been compared with those provided by the model in order to validate the model.

   Determining Of Hf Cm Model Impedance Parameters With ANN For EMI Emis.
By K. Gulez; N. Mutoh; F. Harashima; K. Ohnishi; M. Uzunoglu [View]
[Download]

Abstract: Predicting and solving EMI emissions related to Common Mode (CM) ones in pulse with modulation PWM inverter induction motor drive systems requires various frequency-dependent effects to be considered. Thus, the application of filter circuitry to increase the performance per size and prevent dependency on some parameters of the motor for Electro-Magnetic Interference (EMI) filter is considered. The major problems are power line frequency rejection and the compensation of the feedback loop, which is influenced by the wide-ranging utility impedance. Thus, the proposed method allows another way to determine High Frequency (HF) Common Mode (CM) impedance parameters on the design stage of EMI filter to prevent the EMI noise applying to the conducted electromagnetic emissions generally caused by power supply firstly, then secondly to Common Mode (CM) path of the motor drive system.

   EMI Interference Supression in Symmetrical non-regulated Power Supply
By F.P. Ridao; J.M. Carrasco; L.G. Franquelo [View]
[Download]

Abstract: Different non-regulated symmetrical power supplies for audio power amplifier are presented in this work, where the conducted interference to the ac power grid, measured by a LISN, has been suppressed to the minimum. EMI measurements in different topologies have been compared in this paper. Also, several conventional EMI suppression components have been tested in these topologies in order to reduce EMI interference. As a result several rectifier circuits for main power supply with very low emissions are presented in this paper based on fast rectifier diodes.

   Evaluation and Prediction of conducted EMI Generated by Inverters
By E. Hoene; W. John; M. Michel; H. Reichl [View]
[Download]

Abstract: For the purpose of investigation of electromagnetic interference mechanisms in power electronics, calculation and measurement methods to characterize sources and spreading paths of interference were presented. The methods were used to model a commercial converter for induction motors. In this investigation magnetic coupling between components and the properties of the electromagnetic environment are shown to be important for the propagation of interference in high power density devices. The results of EMI simulation were compared to measurements to prove the validity of the proposed methods and the models of the setup. The derived description of interference mechanisms allows a prediction of interference levels and efficiency of filter measures in a specific topology.

   FDTD Based Analysis of Heat Sink Effects in SMPS Circuits
By G. Felic; R. Evans [View]
[Download]

Abstract: EMC is an integral part of Switched Mode Power Supply design. An optimal SMPS could be considered as one, which achieves the best possible compromise between power losses and EMI disturbances, both of which are directly related to the switching speed of the power devices. Thus the process of finding an acceptable switching speed becomes a critical part of the design process. This paper considers heat sink aspects of this power-loss/EMI trade-off.

   Ground Interconnections Optimal Topology for DC Power Supply
By D. Dragomirescu; O. Dragomirescu [View]
[Download]

Abstract: This paper provides an analysis of ground noise coupling problem for DC power supplies. Due to interconnection topology, electromagnetic compatibility problems occur between the different stages of power supplies, leading to high output voltage ripple, system oscillations or modifications of the designed system parameters. The ground interconnection optimal topology and the methodology to obtain it are given.

   Indices to Evaluate the Quality of Power Absorbed by Non-Linear Loads
By A. Dell'Aquila; M. Marinelli; V. Monopoli; P. Zanchetta [View]
[Download]

Abstract: Power quality monitoring is a relatively recent problem but its complexity has been already proved. In fact, the propagation of the harmonic distortion has been affecting the electrical networks for several years, but it is recently assuming a growing importance because of the large diffusion of non-linear loads. Hi-fi, computer, discharge lamp, battery charge, UPS, electrical drive are typical distorting loads. In this work two new indices to evaluate the quality of the power absorbed by a non-linear load have been proposed. They rely on voltage and current waveform measurements at the point of common coupling. Several simulations and experimental tests have been carried out and they have proved that these new indices are less sensitive to the network voltage conditions than the traditional ones. They are able not only to give an estimate of the harmonic distortion of the current flowing in an electrical network, but they can also evaluate the responsibilities of distributors and customers.

   Integrated Design Approach of Medium Power Inverters optimized for EMC
By M. Chiadò Caponet; F.Profumo [View]
[Download]

Abstract: Today's state of the art power electronics system require the design engineers to employ an integrated approach, utilizing IGBT's, heatsink, capacitors and gate driver circuits at their peak performance. While functionality is of course always important, the problem of manufacturability, cost and electromagnetic compatibility (EMC) are elements that have to be kept into account. In this paper the authors show how electromagnetic interference caused by power electronic circuits can be reduced by the minimization of the total inductance commutation loop of an inverter leg. At the same time special attention is due to the compactness of the inverter especially as regard to the heatsink and the thermal issues. The goal is a proper design and construction of the inverter so tackling EMI directly at the source where most EMI is generated. In this way application of expensive EMI filters can be avoided. Moreover the analysis of the thermal behavior is showed. In order to reach this goal a proper selection and design of the inverter parts have been made and implemented. Specifically, a prototype of converter has been developed to reach the maximum reduction of the stray inductance commutation loop and the maximum compactness using the actual available technology. Experimental results are given to show the validity of this approach.

   Investigation of Phenomena in the System Voltage Inverter-Cable-Motor
By Z. Peroutka; V. Kus [View]
[Download]

Abstract: The paper deals with investigation of adverse effects in the system voltage inverter – cable – induction motor. Very important part of analysis is a model of the motor, especially determination of motor capacitances. Several representations (one-phase and three-phase) of the motor and the cable suitable for determination of motor transient overvoltage have been proposed. Factors contributing to a motor overvoltage are described. Influence of cable length, du/dt (rise time Ton) of voltage pulses and motor characteristics is investigated. The results are compared with data obtained from a lot of experiments and simulations.

   Limitation of small DC motor drives due to the EMC EEC Standards
By L. Ferraris [View]
[Download]

Abstract: The EEC Standards establish important limitations for any kind of electrical apparatus under the point of view of EMC problems. That implies heavy restrictions to the Power Electronics technical freedom. In this paper the important sector of small phase-controlled DC drives is studied. After an introduction to the problem a deep analysis is carried out, obtaining the maximum adoptable power for such devices depending on the voltage. The legal constraints result very heavy.

   Modeling and HF Performance of Power Cables in Electrical Motor Drives
By M. Cacciato; A. Consoli; L. Finocchiaro; A. Testa [View]
[Download]

Abstract: By referring to Induction Motor Drive (IMD) systems, the present paper investigates the influence on the power cables connecting the inverter to the motor of dangerous motor overvoltages and electromagnetic emissions. In order to predict such phenomena, a suitable modeling of standard cables is obtained by finite element analysis. By connecting the model of the cable with a proper High Frequency (HF) model of the induction machine and the converter, a representation of the whole drive is developed. SPICE simulations are carried out using the proposed drive model and compared with experimental results obtained on a standard 1,1 kW induction motor drive.

   New Methods to Suppress EMI Noises in the Motor Drive System
By N. Mutoh; M. Ogata; K. Gulez; F. Harashima [View]
[Download]

Abstract: New methods are studied that can suppress EMI noises, especially common mode currents produced in the motor drive system. One is a packaging technique that forms power converters using a four-layer printed power circuit board. The other is a method based on the generation mechanism of common mode currents which was developed from experimental analyses. It is proved by experiments that the former can effectively control common mode currents, including radiated emissions, and the latter can suppress them without any compensators between the inverter and the motor.

   Nonlinear Ferrite Characteristics in Power Line Filters
By P. Horst; M. Albach [View]
[Download]

Abstract: Based on a 6-pole description of mains filters a simultaneous analytical calculation of both common mode and differential mode attenuation is presented. This procedure takes into account the various parasitics of the components and also the complex impedance of the power supply. The conversion of dm-noise to cm-noise is easily predictable from the simulation. Furthermore the influence of the nonlinear characteristics of the ferrite grades on the attenuation is investigated.

   PCB diagnosis with high resolution HF magnetic probe
By J. Gago; D. González; J. Balcells [View]
[Download]

Abstract: A near filed magnetic or electric sensor with high spatial resolution is needed to carry out EMI measurements on PCB in order to properly identify the components that behaves as disturbance sources. The magnetic probes commercially available are not suitable for this purpose: they have good accuracy and enough bandwidth but poor spatial resolution. To overcome this problem, a new magnetic field probe has been designed. This new sensor is described in this paper and provides a flat response up to 220MHz. A comparison of the experimental results of EMI measurements on a microprocessor board done with the new probe and with a commercial one are presented. These results shown that the new magnetic probe is suitable for identifying noisy components and the efficacy of corrective techniques like decoupling capacitors.

   Propagation of conducted electromagnetic interference
By J. Luszcz; K. Iwan; J. Nieznanski [View]
[Download]

Abstract: The paper presents the results of research into the propagation of interference currents and voltages through two-winding pulse transformers. A novel circuit model of the high-frequency transformer is proposed and discussed. The model was developed expressly for the studies of interference generated by power electronic converters. It takes into account the stray capacitances inevitably existing in real transformer windings. The model has been validated by both simulation and experiments.

   Side effects of LISN on EMI measurements in power converters
By J. Balcells; D. González; J. Gago; M. Lamich [View]
[Download]

Abstract: Several measurements were performed on a power converter to obtain a model which allowed the prediction of conducted EMI . The goal was to identify the relevant components and lay-out parameters influencing the EMI generation and transmission. Some of the measured disturbances could not be attributed to any real or parasitic component in the converter and finally, it was found that they came from the measuring set-up (namely from the standard LISN and the measuring through the high pass surge suppression filter, HPF). The introduction of real models for the measuring equipment in the simulation, allowed a precise coincidence between simulated and measured EMI and showed that the standard measuring equipment introduce some extra disturbances which are no present in the normal working conditions.

   Switching cell analyse as main EMC sources in Power Electronic.
By C. Duloung; M. Bensoam; D. Lafore [View]
[Download]

Abstract: Power electronic equipment’s EMC performances are very difficult to analyse. This paper focusing on main sources of EMC disturbances: the switching cell. We present an hybrid method able to characterise EMC’s switching sources, using current and voltage waveforms and associated signal processing.

EPE 2001 - Topic 11a: EMC
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2001 - Conference > EPE 2001 - Topic 11: SYSTEMS ENGINEERING > EPE 2001 - Topic 11a: EMC
	[return to parent folder]

	Analysis of Mis-operation Caused by EMI in Power Electronic Equipment By Dehong Liu; Jianguo Jiang; Zhengming Zhao	[View] [Download]
Abstract: Mis-operation caused by EMI in power electronic equipment is a troublesome problem that often occurs during design and operation process. This paper is mainly focused on EMI sources, propagation characteristics, and suppression schemes in power electronic equipment. As an example, disturbances in the control circuit of a 6kW charger with a mis-operation fault are measured. The EMI caused by switching device IGBT in the main circuit and driving pulses in the control circuit are compared. Then by a system function approach, the high pass characteristic of EMI coupling path from the main circuit to the control circuit board is analyzed. Using the system function, EMI in the control circuit caused by the IGBT is predicted. To diagnose the mis-operation in the control circuit, susceptibilities of several digital logic integrated circuits(ICs) to pulse like EMI, and suppression schemes are studied through experiments. As a result, mis-operation in the control circuit of the charger is eliminated.

	Bearing current pulse rate in standard PWM drives. By A. Kempski; R. Strzelecki; R. Smoleñski; J. Bojarski; M. Klytta	[View] [Download]
Abstract: This paper examines AC motor bearing currents (Electric Discharge Machining – EDM) resulting from a common mode (CM) voltage in a drives fed by PWM voltage source inverters. Subject literature of the problem of bearing currents has been primarily concerned with theoretical analysis of bearing current phenomena and possible mechanisms for bearing damage [1-4]. It has been rarely related to the quantitative results of the bearing currents appearance. However, it is a reasonable assumption that an amplitude and the number of EDM current pulses in a duty cycle are the most important rate–determining factors of premature bearing damage. In this paper we present the experimental results of the distribution of an amplitude and a rate of bearing current pulses. Parameters of the distribution have been also determined. They can be the basis of comparative analysis of influence of the CM current mitigation methods on the risk of electrically induced bearing damage. Especially, we focus on the improved systems with a CM choke and a CM transformer and an active filter for the CM voltage cancellation.

	Characterization of the field radiated by a magnetic component By J. Lorange; B. Cogitore; T. Creuzet; J-P. Keradec; J-L. Schanen; C. Brun	[View] [Download]
Abstract: The presented work aims to characterize the magnetic field produced by magnetic components up to 50 cm far and 10 MHz. To sum up all the practical results by less than 15 parameters, we use limited multipole expansion together with related spherical harmonic functions. Measurement of loop antenna voltage needs special care because it often is in the µV range. In this paper we describe our theoretical approach and the measurement bench which has been built. To end, we present some preliminary results regarding a current loop.

	Common Mode EMI prediction for three-phase inverter By D. González; J. Balcells; J. Gago; M. Lamich	[View] [Download]
Abstract: In this paper a simplified mathematical model for the prediction of the conducted EMI generated by a three-phase inverter is presented. The model allows the prediction of disturbances that propagates to the DC bus and to the load, but special attention has been paid to the Common Mode (CM) current disturbances at the load side. The model, that is based on the frequency domain, identifies the source of disturbance and its propagation paths as well. The model is used to study an undesired effect that take place in the induction motor drives: the circulation of CM currents through the motor. These currents are the origin of many problems well described on the literature and many solutions have been proposed to fix the problem. In this paper, two different vector modulation techniques are used: the Classical Space Vector Modulation (CSVM) and the CM Reduction Space Vector Modulation (CMRSVM). The experimental results obtained from the experimental plant has been compared with those provided by the model in order to validate the model.

	Determining Of Hf Cm Model Impedance Parameters With ANN For EMI Emis. By K. Gulez; N. Mutoh; F. Harashima; K. Ohnishi; M. Uzunoglu	[View] [Download]
Abstract: Predicting and solving EMI emissions related to Common Mode (CM) ones in pulse with modulation PWM inverter induction motor drive systems requires various frequency-dependent effects to be considered. Thus, the application of filter circuitry to increase the performance per size and prevent dependency on some parameters of the motor for Electro-Magnetic Interference (EMI) filter is considered. The major problems are power line frequency rejection and the compensation of the feedback loop, which is influenced by the wide-ranging utility impedance. Thus, the proposed method allows another way to determine High Frequency (HF) Common Mode (CM) impedance parameters on the design stage of EMI filter to prevent the EMI noise applying to the conducted electromagnetic emissions generally caused by power supply firstly, then secondly to Common Mode (CM) path of the motor drive system.

	EMI Interference Supression in Symmetrical non-regulated Power Supply By F.P. Ridao; J.M. Carrasco; L.G. Franquelo	[View] [Download]
Abstract: Different non-regulated symmetrical power supplies for audio power amplifier are presented in this work, where the conducted interference to the ac power grid, measured by a LISN, has been suppressed to the minimum. EMI measurements in different topologies have been compared in this paper. Also, several conventional EMI suppression components have been tested in these topologies in order to reduce EMI interference. As a result several rectifier circuits for main power supply with very low emissions are presented in this paper based on fast rectifier diodes.

	Evaluation and Prediction of conducted EMI Generated by Inverters By E. Hoene; W. John; M. Michel; H. Reichl	[View] [Download]
Abstract: For the purpose of investigation of electromagnetic interference mechanisms in power electronics, calculation and measurement methods to characterize sources and spreading paths of interference were presented. The methods were used to model a commercial converter for induction motors. In this investigation magnetic coupling between components and the properties of the electromagnetic environment are shown to be important for the propagation of interference in high power density devices. The results of EMI simulation were compared to measurements to prove the validity of the proposed methods and the models of the setup. The derived description of interference mechanisms allows a prediction of interference levels and efficiency of filter measures in a specific topology.

	FDTD Based Analysis of Heat Sink Effects in SMPS Circuits By G. Felic; R. Evans	[View] [Download]
Abstract: EMC is an integral part of Switched Mode Power Supply design. An optimal SMPS could be considered as one, which achieves the best possible compromise between power losses and EMI disturbances, both of which are directly related to the switching speed of the power devices. Thus the process of finding an acceptable switching speed becomes a critical part of the design process. This paper considers heat sink aspects of this power-loss/EMI trade-off.

	Ground Interconnections Optimal Topology for DC Power Supply By D. Dragomirescu; O. Dragomirescu	[View] [Download]
Abstract: This paper provides an analysis of ground noise coupling problem for DC power supplies. Due to interconnection topology, electromagnetic compatibility problems occur between the different stages of power supplies, leading to high output voltage ripple, system oscillations or modifications of the designed system parameters. The ground interconnection optimal topology and the methodology to obtain it are given.

	Indices to Evaluate the Quality of Power Absorbed by Non-Linear Loads By A. Dell'Aquila; M. Marinelli; V. Monopoli; P. Zanchetta	[View] [Download]
Abstract: Power quality monitoring is a relatively recent problem but its complexity has been already proved. In fact, the propagation of the harmonic distortion has been affecting the electrical networks for several years, but it is recently assuming a growing importance because of the large diffusion of non-linear loads. Hi-fi, computer, discharge lamp, battery charge, UPS, electrical drive are typical distorting loads. In this work two new indices to evaluate the quality of the power absorbed by a non-linear load have been proposed. They rely on voltage and current waveform measurements at the point of common coupling. Several simulations and experimental tests have been carried out and they have proved that these new indices are less sensitive to the network voltage conditions than the traditional ones. They are able not only to give an estimate of the harmonic distortion of the current flowing in an electrical network, but they can also evaluate the responsibilities of distributors and customers.

	Integrated Design Approach of Medium Power Inverters optimized for EMC By M. Chiadò Caponet; F.Profumo	[View] [Download]
Abstract: Today's state of the art power electronics system require the design engineers to employ an integrated approach, utilizing IGBT's, heatsink, capacitors and gate driver circuits at their peak performance. While functionality is of course always important, the problem of manufacturability, cost and electromagnetic compatibility (EMC) are elements that have to be kept into account. In this paper the authors show how electromagnetic interference caused by power electronic circuits can be reduced by the minimization of the total inductance commutation loop of an inverter leg. At the same time special attention is due to the compactness of the inverter especially as regard to the heatsink and the thermal issues. The goal is a proper design and construction of the inverter so tackling EMI directly at the source where most EMI is generated. In this way application of expensive EMI filters can be avoided. Moreover the analysis of the thermal behavior is showed. In order to reach this goal a proper selection and design of the inverter parts have been made and implemented. Specifically, a prototype of converter has been developed to reach the maximum reduction of the stray inductance commutation loop and the maximum compactness using the actual available technology. Experimental results are given to show the validity of this approach.

	Investigation of Phenomena in the System Voltage Inverter-Cable-Motor By Z. Peroutka; V. Kus	[View] [Download]
Abstract: The paper deals with investigation of adverse effects in the system voltage inverter – cable – induction motor. Very important part of analysis is a model of the motor, especially determination of motor capacitances. Several representations (one-phase and three-phase) of the motor and the cable suitable for determination of motor transient overvoltage have been proposed. Factors contributing to a motor overvoltage are described. Influence of cable length, du/dt (rise time Ton) of voltage pulses and motor characteristics is investigated. The results are compared with data obtained from a lot of experiments and simulations.

	Limitation of small DC motor drives due to the EMC EEC Standards By L. Ferraris	[View] [Download]
Abstract: The EEC Standards establish important limitations for any kind of electrical apparatus under the point of view of EMC problems. That implies heavy restrictions to the Power Electronics technical freedom. In this paper the important sector of small phase-controlled DC drives is studied. After an introduction to the problem a deep analysis is carried out, obtaining the maximum adoptable power for such devices depending on the voltage. The legal constraints result very heavy.

	Modeling and HF Performance of Power Cables in Electrical Motor Drives By M. Cacciato; A. Consoli; L. Finocchiaro; A. Testa	[View] [Download]
Abstract: By referring to Induction Motor Drive (IMD) systems, the present paper investigates the influence on the power cables connecting the inverter to the motor of dangerous motor overvoltages and electromagnetic emissions. In order to predict such phenomena, a suitable modeling of standard cables is obtained by finite element analysis. By connecting the model of the cable with a proper High Frequency (HF) model of the induction machine and the converter, a representation of the whole drive is developed. SPICE simulations are carried out using the proposed drive model and compared with experimental results obtained on a standard 1,1 kW induction motor drive.

	New Methods to Suppress EMI Noises in the Motor Drive System By N. Mutoh; M. Ogata; K. Gulez; F. Harashima	[View] [Download]
Abstract: New methods are studied that can suppress EMI noises, especially common mode currents produced in the motor drive system. One is a packaging technique that forms power converters using a four-layer printed power circuit board. The other is a method based on the generation mechanism of common mode currents which was developed from experimental analyses. It is proved by experiments that the former can effectively control common mode currents, including radiated emissions, and the latter can suppress them without any compensators between the inverter and the motor.

	Nonlinear Ferrite Characteristics in Power Line Filters By P. Horst; M. Albach	[View] [Download]
Abstract: Based on a 6-pole description of mains filters a simultaneous analytical calculation of both common mode and differential mode attenuation is presented. This procedure takes into account the various parasitics of the components and also the complex impedance of the power supply. The conversion of dm-noise to cm-noise is easily predictable from the simulation. Furthermore the influence of the nonlinear characteristics of the ferrite grades on the attenuation is investigated.

	PCB diagnosis with high resolution HF magnetic probe By J. Gago; D. González; J. Balcells	[View] [Download]
Abstract: A near filed magnetic or electric sensor with high spatial resolution is needed to carry out EMI measurements on PCB in order to properly identify the components that behaves as disturbance sources. The magnetic probes commercially available are not suitable for this purpose: they have good accuracy and enough bandwidth but poor spatial resolution. To overcome this problem, a new magnetic field probe has been designed. This new sensor is described in this paper and provides a flat response up to 220MHz. A comparison of the experimental results of EMI measurements on a microprocessor board done with the new probe and with a commercial one are presented. These results shown that the new magnetic probe is suitable for identifying noisy components and the efficacy of corrective techniques like decoupling capacitors.

	Propagation of conducted electromagnetic interference By J. Luszcz; K. Iwan; J. Nieznanski	[View] [Download]
Abstract: The paper presents the results of research into the propagation of interference currents and voltages through two-winding pulse transformers. A novel circuit model of the high-frequency transformer is proposed and discussed. The model was developed expressly for the studies of interference generated by power electronic converters. It takes into account the stray capacitances inevitably existing in real transformer windings. The model has been validated by both simulation and experiments.

	Side effects of LISN on EMI measurements in power converters By J. Balcells; D. González; J. Gago; M. Lamich	[View] [Download]
Abstract: Several measurements were performed on a power converter to obtain a model which allowed the prediction of conducted EMI . The goal was to identify the relevant components and lay-out parameters influencing the EMI generation and transmission. Some of the measured disturbances could not be attributed to any real or parasitic component in the converter and finally, it was found that they came from the measuring set-up (namely from the standard LISN and the measuring through the high pass surge suppression filter, HPF). The introduction of real models for the measuring equipment in the simulation, allowed a precise coincidence between simulated and measured EMI and showed that the standard measuring equipment introduce some extra disturbances which are no present in the normal working conditions.

	Switching cell analyse as main EMC sources in Power Electronic. By C. Duloung; M. Bensoam; D. Lafore	[View] [Download]
Abstract: Power electronic equipment’s EMC performances are very difficult to analyse. This paper focusing on main sources of EMC disturbances: the switching cell. We present an hybrid method able to characterise EMC’s switching sources, using current and voltage waveforms and associated signal processing.