A measurement system for radiated transient electromagnetic interference based on general purpose instruments

This paper presents a measurement system intended to be used to assets the radiated electromagnetic interference (EMI) in both time and frequency domains. In order to keep the measurement setup as accessible and practical as possible, the direct measurements are recorded with a general purpose digital oscilloscope and processed with a commonly available personal computer. The measurement system was validated for radiated emissions testing using well-known, controlled transient and continuous signals emulating typical interferences. The results are in satisfactory agreement with those provided by a conventional EMI receiver for different types of detectors. The proposed approach shows that, currently, it is possible to implement a timesaving, accurate and generally inexpensive time domain measurement system for radiated emissions that is capable to overcome the limitations of the superheterodyne EMI receivers regarding the measurement of discontinuous electromagnetic disturbances and also able to provide additional enhanced features to evaluate and troubleshoot EMI problemsPostprint (published version

Time domain measurement method for electromagnetic interference

The aim of this research was to study the feasibility of the time domain electromagnetic interference (TDEMI) measurement method in MIL-STD-461F compliance measurements. In the TDEMI measurement method, the measurement in time domain is performed with digital oscilloscope. After time domain measurement, comparable frequency domain amplitude spectrum is produced by Discrete Fourier Transform and by other signal processing with PC. The pros and cons of TDEMI measurement method compared to frequency domain measurement method are also evaluated in this research as well as statistical properties of TDEMI measurement results. The research is divided in three major parts. The first part of the research is a literature review of the most essential publications related to TDEMI measurement methods and the introduction to the CE102 test method which was studied as an example. The second and the most important part of the research is the building up the TDEMI measurement system and EMI measurements with built system. Improvements for the TDEMI measurement system are also introduced in the second part. The third part is the evaluation of the built TDEMI measurement system. This is done by statistical analysis of measurement results and by comparative measurements with standard frequency domain measurement system. The conclusion of the research is that the TDEMI measurement method is a feasible low-cost alternative for the frequency domain measurements in MIL-STD-461F CE102 measurements. In most of the practical cases the TDEMI measurement method is more time consuming than the CE102 frequency domain measurement, but if the interference signal contains infrequent phenomena, TDEMI measurement method may save time. The building up a TDEMI measurement system requires deep knowledge in measurement technology and in signal processing. The TDEMI measurement method has also many benefits and it seems to be developable method. Possible further research areas are related to application of different window functions in the algorithm for narrowband interference and to measurements of transient interference signals with TDEMI measurement system

Estimation of real traffic radiated emissions from electric vehicles in terms of the driving profile using neural networks

The increment of the use of electric vehicles leads to a worry about measuring its principal source of environmental pollution: electromagnetic emissions. Given the complexity of directly measuring vehicular radiated emissions in real traffic, the main contribution of this PhD thesis is to propose an indirect solution to estimate such type of vehicular emissions. Relating the on-road vehicular radiated emissions with the driving profile is a complicated task. This is because it is not possible to directly measure the vehicular radiated interferences in real traffic due to potential interferences from another electromagnetic wave sources. This thesis presents a microscopic artificial intelligence model based on neural networks to estimate real traffic radiated emissions of electric vehicles in terms of the driving dynamics. Instantaneous values of measured speed and calculated acceleration have been used to characterize the driving profile. Experimental electromagnetic interference tests have been carried out with a Vectrix electric motorcycle as well as Twizy electric cars in semi-anechoic chambers. Both the motorcycle and the car have been subjected to different urban and interurban driving profiles. Time Domain measurement methodology of electromagnetic radiated emissions has been adopted in this work to save the overall measurement time. The relationship between the magnetic radiated emissions of the Twizy and the corresponding speed has been very noticeable. Maximum magnetic field levels have been observed during high speed cruising in extra-urban driving and acceleration in urban environments. A comparative study of the prediction performance between various static and dynamic neural models has been introduced. The Multilayer Perceptron feedforward neural network trained with Extreme Learning Machines has achieved the best estimation results of magnetic radiated disturbances as function of instantaneous speed and acceleration. In this way, on-road magnetic radiated interferences from an electric vehicle equipped with a Global Positioning System can be estimated. This research line will allow quantify the pollutant electromagnetic emissions of electric vehicles and study new policies to preserve the environment

Estimation of real traffic radiated emissions from electric vehicles in terms of the driving profile using neural networks

The increment of the use of electric vehicles leads to a worry about measuring its principal source of environmental pollution: electromagnetic emissions. Given the complexity of directly measuring vehicular radiated emissions in real traffic, the main contribution of this PhD thesis is to propose an indirect solution to estimate such type of vehicular emissions. Relating the on-road vehicular radiated emissions with the driving profile is a complicated task. This is because it is not possible to directly measure the vehicular radiated interferences in real traffic due to potential interferences from another electromagnetic wave sources. This thesis presents a microscopic artificial intelligence model based on neural networks to estimate real traffic radiated emissions of electric vehicles in terms of the driving dynamics. Instantaneous values of measured speed and calculated acceleration have been used to characterize the driving profile. Experimental electromagnetic interference tests have been carried out with a Vectrix electric motorcycle as well as Twizy electric cars in semi-anechoic chambers. Both the motorcycle and the car have been subjected to different urban and interurban driving profiles. Time Domain measurement methodology of electromagnetic radiated emissions has been adopted in this work to save the overall measurement time. The relationship between the magnetic radiated emissions of the Twizy and the corresponding speed has been very noticeable. Maximum magnetic field levels have been observed during high speed cruising in extra-urban driving and acceleration in urban environments. A comparative study of the prediction performance between various static and dynamic neural models has been introduced. The Multilayer Perceptron feedforward neural network trained with Extreme Learning Machines has achieved the best estimation results of magnetic radiated disturbances as function of instantaneous speed and acceleration. In this way, on-road magnetic radiated interferences from an electric vehicle equipped with a Global Positioning System can be estimated. This research line will allow quantify the pollutant electromagnetic emissions of electric vehicles and study new policies to preserve the environment

On low frequency conducted EMI: interference mitigation with focus on the DC switching harmonic in the time and frequency domains

The recent increase of interconnected electrical systems such as power supplies and communication links are creating problems associated with electromagnetic fields generated at different voltage levels and frequencies. Semiconductor switches used in for example Switched Mode Power Supplies are constantly increasing in power rating and frequency limits. In addition, wired communication links are also increasing the working bandwidth and channel capability to transfer more information in less time. Smart grids are receiving much attention from companies and researchers all over the world. Two concerns that drive the research carried out on smart grids are Power Quality and Signal Integrity. This work presents an analysis of conducted emissions with two aims. Firstly, an analysis is made of the simulated and measured data when a DC system generates electromagnetic interference and how to improve or mitigate it with certain frequency modulation techniques by spreading the spectrum of the switching frequency in agreement to an established standard. Secondly, a demonstration of the coupling effects as one of the major concerns when dealing with Electromagnetic Interference sources is presented experimentally. Statistical analyses for these tests are performed to understand the main causes and possible actions to suppress interference and to address Electromagnetic Compatibility between devices. The work presents the following findings. An understanding of the important parameters for frequency modulation techniques called as Spread Spectrum. These parameters are the rate of change for the modulating signal and the modulation index that controls the switching frequency of a modulated DC-DC converter to mitigate the interference measured. The importance of an auxiliary time domain (Bit Error Rate) analysis to measure the interference of a DC-DC converter modulated by Spread Spectrum to understand the main drawback in the emissions measured from a different point of view by means of a Crosstalk environment. The conclusion that Bit Error Rate measurement of a communication signal cannot be decreased using Spread Spectrum Modulation for the power converter as the EMI source. The results obtained use data measured using an EMI receiver and where possible a simulation describing the most important parameters. This work provides interesting and useful points to analyse the Spread Spectrum technique applied to DC power converters and the main advantages and disadvantages

On low frequency conducted EMI: interference mitigation with focus on the DC switching harmonic in the time and frequency domains

The recent increase of interconnected electrical systems such as power supplies and communication links are creating problems associated with electromagnetic fields generated at different voltage levels and frequencies. Semiconductor switches used in for example Switched Mode Power Supplies are constantly increasing in power rating and frequency limits. In addition, wired communication links are also increasing the working bandwidth and channel capability to transfer more information in less time. Smart grids are receiving much attention from companies and researchers all over the world. Two concerns that drive the research carried out on smart grids are Power Quality and Signal Integrity. This work presents an analysis of conducted emissions with two aims. Firstly, an analysis is made of the simulated and measured data when a DC system generates electromagnetic interference and how to improve or mitigate it with certain frequency modulation techniques by spreading the spectrum of the switching frequency in agreement to an established standard. Secondly, a demonstration of the coupling effects as one of the major concerns when dealing with Electromagnetic Interference sources is presented experimentally. Statistical analyses for these tests are performed to understand the main causes and possible actions to suppress interference and to address Electromagnetic Compatibility between devices. The work presents the following findings. An understanding of the important parameters for frequency modulation techniques called as Spread Spectrum. These parameters are the rate of change for the modulating signal and the modulation index that controls the switching frequency of a modulated DC-DC converter to mitigate the interference measured. The importance of an auxiliary time domain (Bit Error Rate) analysis to measure the interference of a DC-DC converter modulated by Spread Spectrum to understand the main drawback in the emissions measured from a different point of view by means of a Crosstalk environment. The conclusion that Bit Error Rate measurement of a communication signal cannot be decreased using Spread Spectrum Modulation for the power converter as the EMI source. The results obtained use data measured using an EMI receiver and where possible a simulation describing the most important parameters. This work provides interesting and useful points to analyse the Spread Spectrum technique applied to DC power converters and the main advantages and disadvantages

Analyse der Netzrückwirkungen und Eingangsfilter gepulster leistungselektronischer Umrichter

Die vorliegende Arbeit behandelt die Bauvolumina von Eingangsfiltern für leistungselektronische Umrichter, da diese neben dem Kühlerbauvolumen ein wesentlicher Faktor für das Gesamtbauvolumen sind.Die Untersuchung wird für kleine Ausgangsleistungen (3 kVA) durchgeführt, da dieser Leistungsbereich das größte Marktsegment einnimmt.Aufgrund neuartiger Halbleitermaterialien werden zukünftig höhere Pulsfrequenzen bei gleichzeitig kleiner Verlustleistung möglich sein. Es ist allgemein bekannt, dass die Eingangsfilterbaugröße durch die gewählte Pulsfrequenz beeinflusst wird, weshalb ein Untersuchungspunkt dieser Arbeit darin besteht, Aussagen über die Eingangsfilterbauvolumina unter Variation der Pulsfrequenz abzuleiten. Neben der Variation der Pulsfrequenz besteht die Möglichkeit, andere Umrichtertopologien als den am Markt etablierten Spannungszwischenkreisumrichter zu verwenden. Aufgrund des nicht vorhandenen Zwischenkreiskondensators ist der Matrixumrichter prinzipiell vollständig in Silizium integrierbar und wird daher ebenfalls hinsichtlich der Eingangsfilterbauvolumina untersucht.Die Hauptzielsetzung der Arbeit liegt daher in einer vergleichenden Betrachtung der Eingangsfilterbauvolumina beider Umrichter unter Variation der Pulsfrequenz sowie der Filterordnung.Die Untersuchung erfolgt auf einer einheitlichen Vergleichsbasis, weshalb ein Filterauslegungsalgorithmus, der sowohl für spannungseinprägende Stromrichter, zu denen der Spannungszwischenkreisumrichter zählt, als auch für stromeinprägende Stromrichter, zu denen der Matrixumrichter zählt, herangezogen wird. Der vorgenannte Filterauslegungsalgorithmus berücksichtigt auch die parasitären Serienwiderstände der Filterbauelemente.Die Filterauslegung erfolgt für Pseudospektren, welche die maximalen Schwingungsamplituden der realen Spektren aller Betriebspunkte enthalten. Die realen Spektren werden mathematisch durch Doppelfourierreihen eindeutig beschrieben. Um auch bei der Ermittlung der Netzrückwirkungen eine einheitliche Vergleichsbasis sicherzustellen, werden allgemeine Modulationsvorschriften angewandt, aus denen sich die Schaltpulse beider Umrichter ableiten lassen. Abschließend werden die Eingangsfilterbauvolumina basierend auf Bauvolumenkennlinien realer Bauelemente für beide Umrichter berechnet und vergleichend diskutiert