Showing papers on "Electromagnetic compatibility published in 2000"

A vector controlled current-source PWM rectifier with a novel current damping method

Abstract: Three-phase current-type pulse width modulation (PWM) rectifiers are becoming increasingly popular as the front-end converter unit in power electronic systems due to tighter electromagnetic compatibility (EMC) regulations. In this paper the control of the current source PWM rectifier in the synchronously rotating reference frame is discussed. A control system is presented in which the active and reactive power are independently controlled with real and imaginary axis components of the supply current vector. A new damping method for supply current oscillations is introduced. The method operates in an open-loop manner and is very suitable for microcontroller implementation since the calculation power demand is low. Furthermore, it is shown that in the synchronously rotating coordinates, where the sinusoidal variables appear as DC quantities, the compensation of the reactive power drawn by the supply filter can be done very easily. The proposed control methods are realized using a single-chip Motorola MC68HC916Y1 microcontroller. The experimental tests show excellent performance in both steady state and transient conditions.

Techniques for input ripple current cancellation: classification and implementation

Abstract: Switching power supplies, due to their high-frequency switching operation, draw a substantial amount of input ripple current, which manifests as undesirable electromagnetic interference (EMI). This paper discusses the cancellation methods, and classifies the basic circuit configurations for ripple current cancellation. The basis of discussion is a "nullification" process, which call be described effectively in terms of the ideal circuit element nullor. Both active and passive implementation examples are given and experimentally demonstrated.

Reverberating chamber electromagnetic field in presence of an unstirred component

Abstract: A theoretical model for the electromagnetic field within a reverberating chamber in presence of an unstirred component is presented. Due to the stochastic nature of the electromagnetic field within the chamber, a statistical electromagnetic approach is developed and tested versus measurements. On the theoretical side, such a physical model is representative of many complex electromagnetic environmental situations, e.g., urban environments, and, therefore, it is of great relevance in the EMC field. On the applicative side, the model can be furthered in order to characterize a reverberating chamber whether it is well operated or not and to set up an environment with a specific amount of direct coupling in conjunction with a stochastic field.

PAPER Special Issue on Recent Progress in Electromagnetic Compatibility Technology Common-Mode-Current Generation Caused by Difference of Unbalance of Transmission Lines on a Printed Circuit Board with Narrow Ground Pattern

Abstract: SUMMARY This paper explains a mechanism of commonmode generation on a printed circuit board with a narrow ground pattern. A transmission line has its value of degree of unbalance. At a connection point of two transmission lines having different degrees of unbalance, common mode voltage is generated proportional to the difference, and it drives common mode current. The authors propose a method to evaluate common mode current distribution and verify it by measurement. Although calculated common mode current is larger than measured one by a few dBs, both of them are proportional to the degree of unbalance. An EMI reduction technique, ‘unbalance matching,’ is also proposed.

Computer simulation of ESD from voluminous objects compared to transient fields of humans

Abstract: Computer simulation of electrostatic discharge (ESD) for simplified objects is described and compared to measured transient fields of human/metal ESD. The simulation algorithm uses the method of moments in time domain, coupled with nonlinear arc resistance model. Transient currents and fields are analyzed from the electromagnetic compatibility (EMC) point of view. Validation of the numerical simulation is done by comparison to experimental data. The simulated structure models the human/metal ESD in its peak current and field values and their derivatives reasonably well.

Directivity of the test device in EMC measurements

Abstract: We present a statistical theory for estimating the directive characteristics of unintentional emitters based and the electrical size of the device. We compare this theory to directivity derived from pattern measurements in an anechoic chamber. We also use this theory to predict the maximum radiated fields based on total radiated power measurements in the reverberation chamber.

Electromagnetic interference on medical equipment by low-power mobile telecommunication systems

Abstract: There have been a number of reports of electromagnetic interference (EMI) on electronic medical equipment caused by mobile telecommunication systems. In Japan, the use of the personal handy-phone system (PHS) has greatly expanded within urban areas, PHS handsets transmit EM signals at a frequency of 1.9 GHz and have a peak radiated power of 80 mW. This power level is lower than that of other mobile telecommunication systems. Two studies were carried out. One was to determine whether or not PHS interferes with electronic medical equipment in hospitals. We observed no EMI on electronic medical equipment when the PHS handset was in either the speaking mode or on standby. The second study was to observe EMI from 1.9-GHz signals at several radiation power levels. Although EMI was not observed at the radiated peak power of the PHS handset, EMI on some of the tested equipment was observed when the radiated power was ten or more times higher than that of the PHS handset.

Circuit analysis of electromagnetic radiation and field coupling effects for networks with embedded full-wave modules

Abstract: With continually increasing operating frequencies, the analysis of electromagnetic interference (EMI)-related effects is becoming an important issue for high-speed designs. An algorithm is presented for fast analysis of radiation and incident field coupling effects in high-speed circuits. The proposed technique provides an efficient means for combining the solutions from full-wave field solvers such as the finite-difference time-domain (FDTD) method with circuit level simulators such as SPICE for calculating radiated/coupled fields in arbitrarily shaped interconnect structures. The technique speeds up the whole simulation process by employing a model-reduction-based approach, and also overcomes the numerical stability problems associated with the FDTD, in the presence of nonlinear terminations. In addition, the proposed algorithm provides a direct access to existing vast device libraries of SPICE in EMI analysis.

Noncontact type IC card and system therefor

Abstract: A noncontact type IC card includes an electromagnetic induction coil, integrated circuit, and switch. The electromagnetic induction coil receives the energy of an electromagnetic field radiated from an external device. The integrated circuit can be operated by driving power supplied by the energy of the electromagnetic field. The switch is provided on the electromagnetic induction coil for receiving the energy of the electromagnetic field and switches the inductance of the electromagnetic induction coil.

Electromagnetic field receiving apparatus

Abstract: PROBLEM TO BE SOLVED: To expand operable region of an electromagnetic field receiving apparatus. SOLUTION: Antenna circuits 20, 21 receive electromagnetic waves transmitted from an electromagnetic field transmission apparatus 1. A rectifier circuit 22 acquires driving electric power for its own apparatus from the electromagnetic wave received at the antenna circuits 20, 21. A constant voltage circuit 23 converts the output voltage of the rectifier circuit 22 to a constant voltage. An impedance control circuit 31 repeats a control action which changes an impedance of its own apparatus so that the output voltage of the rectifier circuit 22 becomes equal to the desired voltage set value, thereby controls a quantity of received power from the electromagnetic field transmission apparatus 1.

An analytical-FDTD method for near LEMP calculation

Abstract: The paper presents a hybrid method for evaluating the electromagnetic field in the vicinity of the lightning channel base. Several models have been proposed for this purpose, but, in spite of general agreement on the magnetic field results, the literature shows quite different results concerning the intensity and waveshape of the near electric field. The proposed method is an alternative approach that takes advantage of this fact to calculate, first, the magnetic field, and, secondly, based partially on the FDTD method, the electric field. The suitability of this procedure is checked through the comparison with another method, for a particular configuration proposed in the literature.

Hybrid moment-method physical-optics formulation for modeling the electromagnetic behavior of on-board antennas

Abstract: On-board antenna design involves aspects such as optimization of radiation patterns, control of electromagnetic interference and disturbance (EMC/EMI), the assessment of radiation hazards, etc. This paper describes a hybrid moment-method physical-optics (MM–PO) approach that has been shown to be an efficient and accurate tool to predict the above-mentioned electromagnetic aspects concerning antennas installed on board. Some numerical results are presented and compared with a reference MM solution in order to illustrate the accuracy and efficiency of the proposed approach. © 2000 John Wiley & Sons, Inc. Microwave Opt Technol Lett 27: 88–93, 2000.

Experimental verification of enhanced electromagnetic compatibility in chaotic FM clock signals

Abstract: Chaos-based quasi-stationary frequency modulation has been shown to significantly reduce the electromagnetic interference due to possibly high frequency clock signals with respect to previously proposed and patented methods. Arguments are given highlighting the link between the spectrum of the modulated signal and the invariant probability density function of the chaotic system generating the modulating signal. Finally, experimental measurements are shown confirming the advantages of the proposed method and its applicability for different values of the victim apparatus bandwidth.

Low stray inductance bus bar design and construction for good EMC performance in power electronic circuits

Abstract: Ten years after the publication of the EC Directive 89/336, research and development related to electromagnetic compatibility have covered many aspects in the design and development of electrical and electronic equipment. Different solutions regarding these problems were presented in recent years, in order to minimize the electromagnetic interference, but new and innovative solutions are still being studied. In this paper, the authors show to what extent electromagnetic interference caused by power electronic circuits can be minimized with the use of planar busbars. Indeed, the goal is to tackle EMI directly at the source where most EMI is generated by proper design of the inverter busbars. A planar busbar design was made and implemented, Measurements show the validity of the theoretical approach.

EMI-noise analysis under ASIC design environment

Abstract: Electromagnetic compatibility (EMC) has become more and more important in designing electronic systems. Although electromagnetic radiation itself mainly occurs from off-chip conductors, the ultimate noise source is in LSI chips. Among the noise distribution paths, the power-line conducting noise is the most significant source of electromagnetic interference (EMI)-noise caused by LSIs. This paper introduces an EMI-noise analysis method suitable for application-specific integrated circuit design environment especially focusing on the power-line conducting noise. Modeling method for power network and switching activity, simulation flow, and experimental results are presented. Experimental results show that our modeling methodology estimates capacitance values with sufficient accuracy and reproduces the relative differences in EMI-noise levels.

Combined effects of several, simultaneous, EMI couplings

Abstract: We review the possibility of combined effects when two EMI threats are simultaneously present, something which is never tested in practice. After some quick calculation examples, actual test results are presented for three very possible scenarios of combined exposures, where each one individually is below the threshold of disturbance.

EMC and Safety Design for Photovoltaic Systems (ESDEPS)

Abstract: Within the framework of the project ESDEPS (EMC and Safety Design for PV Systems) electromagnetic compatibility (EMC) and safety aspects of PV systems are investigated in detail. The findings from these investigations shall be the basis for the improvement and/or creation of standards concerning the EMC and safety of PV systems. Topics covered by the project are investigations regarding the electromagnetic environment, like the effect of lightning on PV systems and the effect of transients on the mains on PV inverters, as well as investigations with respect to emissions from PV systems on the mains and DC lines and radiated emissions at radio frequencies.

Shielding effectiveness estimation of enclosures with apertures

Abstract: A curve fitting technique has been used to develop a "phenomenological" model based on numerically collected data for the coupling of electromagnetic energy through apertures into enclosures. It has been shown elsewhere that a simple transmission line formulation predicts well the shielding effectiveness of a rectangular enclosure with apertures. The finite difference time-domain method is used for computing electromagnetic fields within the enclosure with apertures. The investigation is focused on the estimation of shielding effectiveness depending on the number of apertures, their area, test point location within the enclosure as well as the incidence angle and polarization of the electromagnetic field impinging on the enclosure. The obtained results allow estimation of the shielding effectiveness at the enclosure design stage.

Novel EMC debugging methodologies for high-power converters

Abstract: Without a need to power up a system, novel debugging strategies are proposed in this paper to characterize the electromagnetic compatibility (EMC) features of power converters. By externally injecting switching transients to key spots, the noise on various locations can be monitored. Then, by correlating the injected signal to the observed noise, the noise distribution mechanisms can be examined, and the EMC problems under full power operation can be predicted accordingly. Since the signal source is working at much lower voltage and power, and the system tested need not be functional, the tests can be conducted in much earlier development stages, with much less risk and much more freedom. Thorough test results are included in this paper. The case of a traction drive is discussed.

Characterizing the generation & coupling mechanisms of electromagnetic interference noise from an electric vehicle traction drive up to microwave frequencies

Abstract: This paper proposes empirical strategies to characterize traditionally difficult electromagnetic compatibility (EMC) problems of power electronic motor drives, up to hundreds of MHz with high accuracy and providing better understanding to the root causes Very simple concepts and block diagrams are used in this paper Straightforward equations are then developed to predict or confirm important system-level features By treating the noise sources and distribution paths separately, complicated EMC problems are conceptually divided into smaller and easier sub-issues, yielding more insightful perception and pave the road to better mitigation results To confirm the proposed methodology, solid test results are shown in the paper, and followed by thorough discussions Finally, a concise summary is appended to conclude this paper

Electromagnetic compatibility sleeve for electrical interconnections

Abstract: Using an adjustable sleeve that provides electromagnetic interference (EMI) shielding, is lightweight, and is adjustable in its length. The electromagnetic compatibility sleeve is formed by attaching electromagnetic foil shields on one or both sides of an insulating material that is accordion-in-structure in a first embodiment so that its length is flexible. The insulating material can be a very high resistivity and magnetically lossy ferrite material to prevent eddy currents on the inner surface from causing magnetic fields within the insulating material In a second embodiment, the sleeve is made up of telescoping sections so that the length is flexible. This flexible sleeve is attached to systems by the utilization of a mounting bracket, one for each system. The electromagnetic sleeve confines the radiation from a printed circuit extender to within the sleeve and prevents radiation from exiting the systems through enclosure openings by the utilization of the mounting brackets.

Lithium-ion batteries for geosynchronous satellites. Qualification test results of the STENTOR battery

Abstract: SAFT has been engaged in the development and qualification of lithium-ion cells and batteries for space applications since 1996. This paper presents the results obtained during qualification tests on the first battery built for the STENTOR Satellite. The STENTOR satellite is powered by lithium-ion cells only, with two 45 V-80 Ah battery packs, made from cylindrical shaped 40 Ah lithium-ion cells, and including the electronics to monitor cells voltages and balance the cell to cell capacities. Each battery pack weights less than 37 kg. The required capacity is achieved by connecting two 40 Ah cells in parallel prior to connecting it in series. Then 11 of these group of two cells are series connected. The battery includes an automatic by-pass system to prevent any type of cell failure. The two electronics are cross strapped to ensure that the two battery packs have no single point failure. The first complete battery, built in 1999, was submitted for qualification test, which comprises: capacity test; hot and cold temperatures; thermal vacuum tests; vibration/shock tests; and EMC tests. The paper gives a summary of the development results, together with details and analysis of the qualification tests performed.

Testing device for evaluating the immunity of an electronic device to electromagnetic noise

Abstract: A testing device generates electromagnetic noise such as transients, power interruptions and Radio Frequency Interference (RFI) for application to an electronic device to test the immunity of the electronic device to electromagnetic noise or to test the performance of the electronic device during exposure to electromagnetic noise. The testing device promotes an economical and efficient evaluation of Electromagnetic Compatibility (EMC) of an electronic device during product design or otherwise. The testing device includes a switch having electrical contacts for producing electromagnetic noise during a transition between a closed state and an open state of the electrical contacts and a trigger that is coupled to the switch. The trigger is arranged to change states between the closed state and the open state of the electrical contact. An input terminal is associated with the switch for applying electrical energy to the switch. An output terminal is associated with the switch for connection to the electronic device for testing operation of the electronic device in response to the electromagnetic noise.

On the uncertainty in the current waveform measurement of an ESD generator

Abstract: The uncertainty in the current waveform measurement of an electrostatic discharge (ESD) generator is evaluated. The measurands are the current amplitude and the rise time of the output current waveform of the ESD generator. An intuitively simple model is proposed to evaluate the uncertainty in the current amplitude measurement. Type A and Type B evaluations for all contributions to the measurement uncertainty are performed to obtain the combined standard uncertainty. The evaluated expanded uncertainty (95.5% confidence level) of the current amplitude and the rise time at ESD voltages of 2, 4, 6, and 8 kV are within the specification of IEC 61000-4-2. The results show that the uncertainty in the current amplitude measurement stems from the voltage reading of the measuring equipment, the difference between the displayed and the actual voltages of the discharge tip of the ESD generator, and the inaccuracy of the delta time measurement of an oscilloscope, whereas the uncertainty in the rise time measurement mainly originates from the measuring equipment.

Measurement of indoor propagation at 850 MHz and 1.9 GHz in hospital corridors

Abstract: The fields at 850 MHz and 1.9 GHz were measured in five hospital corridors. The field strength tended to decline with distance at a free-space rate within about 2 m of the source, but at a slower rate when further away. Fields at 1.9 GHz declined more slowly than 850-MHz fields. The implications for hospital EMC management are discussed.

Analysis of PCB level EMI phenomena using an adaptive low-frequency plane wave time domain algorithm

Abstract: A novel integral equation based algorithm is proposed that permits the analysis of PCB-level EMI phenomena. The algorithm is based on the multilevel plane wave time domain algorithm (PWTD). For a problem of N/sub T/ temporal and N/sub S/ spatial unknowns involving no sub-wavelength features, the multilevel PWTD algorithm reduces the O(N/sub T/N/sub S//sup 2/) computational cost of a classical marching-on-in-time (MOT) algorithm to O(N/sub T/N/sub S/log/sup 2/N/sub S/). However, PCB structures with fine geometrical details such as very thin slots, closely spaced vias or pins, etc., call for a highly non-uniform spatial discretization of the problem domain. In such cases, a straightforward implementation of the multilevel PWTD scheme cannot achieve a reduced computational complexity. Here, an adaptive low-frequency PWTD algorithm is described to solve this problem. Numerical results are presented to demonstrate the applicability of the scheme to the EMI analysis of complex PCB problems.

Nonlinear EMI simulation of an AM detector at the system level

Abstract: A nonlinear detector simulation technique that can be used together with the discrete technique for a rapid radio receiver electromagnetic compatibility and electromagnetic interference (EMC/EMI) simulation up to the baseband signal processing path at the system level is proposed. The technique presented allows one to simulate an amplitude modulation (AM) detector in the large signal mode as well as in the small signal mode by taking into account the nonlinearity of the detector transfer characteristic. The technique was validated by making comparisons with measurements and PSPICE simulation data.