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American Society for Testing and Materials

Introduction to Electromagnetic Compatibility

Методы подавления шумов и помех в электронных системах. (Noise reduction techniques in electronic systems)

This paper begins with an analysis of the common-mode (CM) noise in a motor drive system. Based on the developed CM noise model, two cancellation techniques, CM noise voltage cancellation and CM noise current cancellation, are discussed. The constraints and impedance requirements for these two cancellation methods are investigated. An active filter with a feedforward current cancellation technique is proposed, implemented, and tested, and techniques to improve the performance of active filters are explored. It is found that due to the limitations of speed, power loss, and gain bandwidth of active filters, active electromagnetic interference (EMI) filters are not good at suppressing high di/dt or high amplitude noise current. Hybrid filters that include a passive filter and an active filter are proposed to overcome the shortcomings of active filters. Hybrid EMI filters are investigated based on the impedance requirements and frequency responses between the passive and active filters. The experiments show that the proposed active filter can greatly reduce noise by up to 50 dB at low frequencies (LFs), and therefore, the corner frequency of the passive filter can be increased considerably; as a result, the CM inductance of the passive filter is greatly reduced. The power loss of the proposed active EMI filter can be well-controlled in the experiments.

Investigation of Hybrid EMI Filters for Common-Mode EMI Suppression in a Motor Drive System

This paper reviews the fundamentals and latest progress of modeling, analysis, and design technologies for signal integrity and electromagnetic compatibility on PCB and package in the past decades. Most results in this field are based on the very rich and highly educational literature produced by Prof. C. Paul in his long scientific career. The inclusion of parameters variability effects is also considered, and it is demonstrated how statistical simulations can become affordable by means of recently-introduced stochastic methods. Finally, the necessity of practical training of designers is mentioned, and an experience relying on realistic PCB demonstrators is illustrated.

Overview of Signal Integrity and EMC Design Technologies on PCB: Fundamentals and Latest Progress

Measurements have been performed in a vibrating intrinsic reverberation chamber (VIRC). This chamber has varying angles between wall, floor and ceiling. Inside the VIRC a diffuse, statistically uniform electromagnetic field is created without the use of a mechanical rotating mode stirrer. In comparison to other reverberation chambers the VIRC displays an improved low frequency behavior, enabling faster, cost effective testing and allows for in-situ measurements. Several measurement results obtained in the VIRC are presented in this paper, such as the change in resonance frequency, the stirring ratio and the power density function.

Experimental results obtained in the vibrating intrinsic reverberation chamber

Static, or electronic, energy meters are replacing the conventional electromechanical meters. Consumers are sometimes complaining about higher energy readings and billing after the change to a static meter, but there is not a clear common or root cause at present. Electromagnetic interference has been observed between active infeed converters as used in photo-voltaic systems and static meters. Reducing the interference levels eliminated inaccurate reading in static meters. Several field investigations failed to identify a clear root cause of inaccurate readings of static energy meters. Experiments were performed in a controlled lab environment. Three-phase meters showed large deviations, even when supplied with an ideal sinusoidal voltage from a fourquadrant power amplifier. Large variations could be observed when non-linear, fast switching, loads were connected. A deviation of +276 % was measured with one static energy meter, +265% with a second and -46% with a third static energy meter. After dismantling it was revealed that the meters with the positive deviation used a Rogowski coil current sensor. The meter with a Hall effect-based current sensor gave the -46% deviation. The fourth meter, with a current transformer, resulted in -10% in one experiment and +8% in another experiment, where the deviations are with respect to a conventional electromechanical meter. Measurements were repeated with more meters and supplied from standard, low internal impedance, mains supply in the laboratory. Deviations of +475%, +566%, +569%, +581%, +582% and -31% and -32% were registered, with again the positive deviation for Rogowski coil current sensors and negative deviations for the Hall sensors.

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Static energy meter errors caused by conducted electromagnetic interference

Reverberation chambers (RC), a name inspired in room acoustics, are also known in literature as reverberating, reverb, mode-stirred or mode-tuned chambers. In their basic form, they consist of a shielded metallic enclosure, forming a cavity resonator, together with some mode-stirring mechanism. The main goal of such stirring mechanism is to generate an amplitude-varying electromagnetic field that is ideally statistically uniform.

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Reverberation chambers a la carte: An overview of the different mode-stirring techniques

Methods for calculating the external inductance of parts of a transmission line are compared. The differences and resemblances of these basic methods are discussed. Closed form equations for several structures, as found in the literature, are given. Furthermore, closed form relations for flat rectangular conductors, with holes or slits, different shapes, are developed and compared with results, if available, presented in the literature. We are particularly interested in the effective external inductance of a part of a transmission line because this inductance is the main cause of a ground noise (or drop, shift, lift) voltage, leading to common mode radiation.

Inductance calculations; methods and equations

The review of techniques used for measurements of permittivity and permeability of materials for quasi-static electromagnetic field.

Frank Leferink

Papers

Experimental results obtained in the vibrating intrinsic reverberation chamber

Static energy meter errors caused by conducted electromagnetic interference

Reverberation chambers a la carte: An overview of the different mode-stirring techniques

Inductance calculations; methods and equations

An overview of the techniques for measuring the dielectric properties of materials