Electromagnetic Compatibility Testing Research Articles

Impact of a Frequency Modulated Pulsewidth Modulation (PWM) Switching Converter on the Input Power System Quality

In this paper, we show that a frequency modulated (FM) source of conducted emission has an adverse effect on a dc power system, although it is believed that frequency modulation of the interferer reduces such effects. Spread spectrum modulation is a commonly proposed technique of electromagnetic interference (EMI) reduction. It is often suggested that an FM pulsewidth modulation ramp be used in a voltage mode controlled dc-dc switching converter for reduction of conducted and radiated EMI. However, this paper shows that this technique is not as beneficial as is commonly perceived. The power quality standard MIL-STD 704, which is the origin of the EMI standard MIL-STD 461, puts restriction on several parameters other than the frequency spectrum of the disturbance, which is the only parameter that is specified in the EMI norms and tested in electromagnetic compatibility (EMC) tests. In this paper, we show that different interferers which are compatible to the same EMC limit, may affect the same power system differently. This difference is noticed if the other power quality parameters are considered. We have also mentioned that the actual benefit from spread spectrum modulation-based EMI reduction depends on the savings in printed circuit board (PCB) footprint area that we get by using a smaller filter. Through a numerical study, we have shown that such a method leads to only a negligible savings in PCB area in spite of significant EMI reduction. Moreover, this brings about a degraded performance on the other parameters that are not normally checked in EMI tests.

Magnetic Cleanliness Program Under Control of Electromagnetic Compatibility for the SELENE (Kaguya) Spacecraft

To achieve the scientific objectives related to the lunar magnetic field measurements in a polar orbit at an altitude of 100 km, strict electromagnetic compatibility (EMC) requirements were applied to all components and subsystems of the SELENE (Kaguya) spacecraft. The magnetic cleanliness program was defined as one of the EMC control procedures, and magnetic tests were carried out for most of the engineering and flight models. The EMC performance of all components was systematically controlled and examined through a series of EMC tests. As a result, the Kaguya spacecraft was made to be very clean, magnetically. Hence reliable scientific data related to the magnetic field around the Moon were obtained by the LMAG (Lunar MAGnetometer) and the PACE (Plasma energy Angle and Composition Experiment) onboard the Kaguya spacecraft. These data have been available for lunar science use since November 2009.

Electromagnetic Compatibility Testing of Implantable Neurostimulators Exposed to Metal Detectors

This paper presents results of electromagnetic compatibility (EMC) testing of three implantable neurostimulators exposed to the magnetic fields emitted from several walk-through and hand-held metal detectors. The motivation behind this testing comes from numerous adverse event reports involving active implantable medical devices (AIMDs) and security systems that have been received by the Food and Drug Administration (FDA). EMC testing was performed using three neurostimulators exposed to the emissions from 12 walk-through metal detectors (WTMDs) and 32 hand-held metal detectors (HHMDs). Emission measurements were performed on all HHMDs and WTMDs and summary data is presented. Results from the EMC testing indicate possible electromagnetic interference (EMI) between one of the neurostimulators and one WTMD and indicate that EMI between the three neurostimulators and HHMDs is unlikely. The results suggest that worst case situations for EMC testing are hard to predict and testing all major medical device modes and setting parameters are necessary to understand and characterize the EMC of AIMDs.

Preliminary study of a reverberation chamber method for multiple-source testing using intermodulation

The illumination of a system under test by multiple sources can lead to intermodulation (IM) effects that give rise to threat signals at the IM frequencies. The result of this is that the electromagnetic (EM) compatibility and signal integrity of that system may be compromised by two or more signals that are, individually, out of the frequency band of concern. As the EM environment continues to be increasingly polluted and electromagnetic compatibility (EMC) tests rely, predominantly, on a single-source illumination, this is an issue that is ripe for further investigation. The statistical nature of the reverberation chamber and its behaviour in isolating the test environment from the ambient (outside) environment indicates that this is a facility worth considering for multiple source (IM) testing. This study discusses the need for such an expansion in test methods, driven by an increasing interest in functional safety. It presents the results of a preliminary, simulation based, study of the reverberation chamber used with multiple sources. The purpose of this study is to demonstrate that the reverberation chamber can provide a facility where worst-case multiple-source EM interference effects can be tested. It concludes that the proposed approach has the potential to be viable and suggests experimental studies to confirm the behaviour and also to confirm that this approach can be used as an indirect method of reducing the lowest working frequency of the reverberation chamber.

A Method of Expanding Operating Frequency Band in a Reverberating TEM Cell by Using a Wire Septum

This paper presents a method of expanding the operating frequency band of a Reverberating TEM Cell (RTC) for electromagnetic compatibility (EMC) testing. To expand the operating frequency band of an RTC, this paper places a wire septum inside the cell instead of a solid septum. The maximum usable frequency (MUF) for TEM cell operation and the lowest usable frequency (LUF) for reverberating chamber operation with the wire septum are studied and compared with a conventional solid septum. The E field strengths inside the RTC are measured and evaluated. The measurement results show that the RTC with the wire septum have similar MUF to the RTC with a solid septum at TEM mode, but have much lower LUF at a reverberating mode, which proves that the operating frequency band of the RTC can be expanded by using the wire septum.

Target Locating Technology and System Exploitation Based on the GPS Technology

Further research on the target locating technology and system exploitation based on the GPS technology is made in this paper, and the locating model based on the GPS technology and the orientation terminal posture gaining model as well as its algorithm based on digital compass are established. On this basis, this paper puts forward a solution to the target locating measurement and controlling system based on GPS and digital compass. The system adopts the structure of the host computer and the client computer: the client computer is the hardware realization of target locating system and also can be operated separately; the host computer monitors the client computer remotely. The system can directly get posture information, with advantages of simple structure, upstanding stability, low price and so on, and can satisfy the function of locating system. The client computer passed through the high and low temperature test, resistance vibration test, electromagnetic compatibility test and so on. In the functional testing, the automatic alignment precision of the system attains to and manual alignment precision attains to , completely match the practical requirements.

Experimental Evaluation of Conducted Emissions by Variable-Speed Drives Under Variable Operating Conditions

This paper presents an experimental study about the effects that various operating conditions have on conducted emissions by variable-speed drives. The objective of the research is to determine what quantities most significantly affect emissions so that electromagnetic compatibility test procedures can be carried out under the most appropriate conditions according to the specific destination of the equipment under test. The obtained measurements would so match the standard's requirement that they represent the worst case for the disturbance emission levels. A quantitative analysis has been made possible by introducing two indexes with values determined by emissions over the measurement band. The effects of voltage asymmetry and amplitude, motor operating frequency, and torque applied to it have been investigated. Results show a strong dependence on motor operating frequency and torque and that the fluctuations in the measured emissions largely depend on the measurement configuration adopted.

Numerical Evaluation of Noncanonical Reverberation Chamber Configurations

This paper aims to present an evaluation of noncanonical mode stirred chambers, whose excitation is carried out by transmission lines. Many configurations are taken into account regarding the influence of the wire arrangement and their phase shift excitation on the field homogeneity. The simulations were carried out within the framework of finite integration technique (FIT) and transmission-line modeling (TLM) methods. Experimental and theoretical results are presented regarding the chamber suitability to electromagnetic compatibility (EMC) tests. It is emphasized the viability of extending the present standard frequency range recommendation to lower frequency values.

Electromagnetic compatibility (EMC) evaluation of the SELENE spacecraft for the lunar radar sounder (LRS) observations

Abstract In order to achieve the lunar subsurface sounding and planetary radio wave observations by the Lunar Radar Sounder (LRS) onboard the SELENE spacecraft, strict electromagnetic compatibility (EMC) requirements were applied for all instruments and the whole system of the spacecraft. In order to detect the lunar subsurface echoes from a depth of 5 km, the radiated emission (RE) limit was determined to be −10 dBμV/m and the common-mode (CM) current limit to be 20 dBμA. The EMC performance of the spacecraft was finally evaluated in the system EMC test held from Oct. 20 to Oct. 22, 2005. There is no broadband noise but some narrowband noises at a level above the CM-current limit in a frequency range from 4 to 6 MHz, in which radar soundings are operated. Based on the noise spectrum within 4–6 MHz, the noise level of FMCW radar sounder is estimated to be 14 dB lower than the CM-current limit. In the SELENE EMC test, the following new techniques were introduced: (1) systematic control and evaluation of CM-current noises were first performed to improve the spacecraft EMC performance; (2) onboard battery operation was utilized for reduction of ambient broadband noises during EMC measurements.

The Antenna as a Transducer: Simple Circuit and Electromagnetic Models

Antennas are key elements in electrical engineering. They are the first and most essential parts of a communication/radar system, and basic instruments for electromagnetic compatibility (EMC) tests and measurements. A good design for a transmitting or receiving antenna system or array may reduce the installation and operating costs more than 30-50%. Moreover (up to a certain extent), noise and interference may be eliminated at the front end of the receivers. A communication or radar antenna system basically covers narrow operating bands and operates in the far field. On the other hand, EMC antennas operate over broad bands and use near fields. This tutorial aims to discuss some aspects of these very well-known devices that are often neglected or forgotten, because of their simplicity.

Validation of a Three-Dimensional Transmission Line Matrix (TLM) Model Implementation of a Mode-Stirred Reverberation Chamber

Reverberation chambers are attractive electromagnetic compatibility test facilities, both economically and technically. Careful design and analysis of these facilities are important, if the results obtained are to be treated with a high level of confidence. Numerical modeling is an important part of the process of reverberation chamber design and analysis. Hence, it is important that the modeling techniques to be used are appropriately validated. Much of the published work to date takes either a statistical or a deterministic view of validation. This paper provides validation evidence for a low-resolution transmission line matrix (TLM) model of a reverberation chamber in a manner approximating the way in which the chamber is used, i.e., validating based on the effects of a simple device under test. A variety of statistical and heuristic approaches have been used to quantify the level of agreement, intending to set the likely lower bound for the quality of comparisons between simulations and measurements. While not drawing any "universal" conclusions about the veracity of the TLM technique, the paper concludes that a relatively simple model of a reverberation chamber provides a useful analysis of the chamber with close comparisons between modeled and measured data.

Application of Impedance Loading to Geometric Transition Radar Absorbent Material

This paper describes a novel, lightweight technique for significantly improving the low-frequency reflectivity performance of conventional geometric transition radar absorbent materials as used typically in anechoic chamber facilities for electromagnetic compatibility testing. The improvement is achieved by the inclusion of impedance-loading elements within the base region of the absorber, and these are implemented in the form of one or more frequency-selective surfaces (FSS). The discussion covers the design of the FSS using computer simulation technology microwave studio, its predicted effect on absorber performance at both normal and oblique incidence, the effect of manufacturing tolerances, and the fabrication and characterization of a prototype-loaded absorber panel.

A Complete Model for Simulating Magnitude and Phase of Emissions from a DUT Placed Inside a GTEM Cell

Since the publication of IEC 61000-4-20, the gigahertz transverse electromagnetic (GTEM) cell has gained popularity in radiated emission and immunity electromagnetic compatibility tests. Various numerical methods such as finite-difference time-domain, finite element method, and method of moments have been used to model the GTEM cell in the pursuit of getting to know the characteristic of the GTEM cell with varying degrees of verification. In this paper, the time-domain transmission line model will be used to model the GTEM cell. The advantages of this method include high accuracy and the ability to model different materials. Thus, the GTEM is realistically modeled including radio absorbing material (RAM) and lumped terminations. In addition, the model of a realistic device under test (DUT) was also included in the GTEM model. The DUT consists of a standard sized box with an aperture, placed in different orientations inside the GTEM for power and phase measurements. The particular features of this paper are: 1) the inclusion of a realistic numerical model of RAM, 2) the inclusion of a realistic DUT model, 3) systematic verification of the model against measurements, and 4) the method of phase measurement in a GTEM cell. Good agreement between the experimental results and simulations is obtained.

Important and interesting aspects of electromagnetic compatibility

Many engineers are interested in avoiding EMC problems because of their difficulty to troubleshoot. Having a better understanding of the threat environment and EMI requirements for instrumentation is one of the best ways to avoid troubleshooting in the EMI lab. While the actual testing can be tedious, EMI testing is a field with many-intriguing instrumentation challenges. There is great opportunity for innovation in these systems, especially in automating the tests. This article describes the author's first industrial experience with electromagnetic compatibility testing and certification for avionics

Differential Mode Input Filter Design for a Three-Phase Buck-Type PWM Rectifier Based on Modeling of the EMC Test Receiver

For a three-phase buck-type pulsewidth modulation rectifier input stage of a high-power telecommunications power supply module, a differential-mode (DM) electromagnetic compatibility (EMC) filter is designed for compliance to CISPR 22 Class B in the frequency range of 150 kHz-30 MHz. The design is based on a harmonic analysis of the rectifier input current and a mathematical model of the measurement procedure including the line impedance stabilization network (LISN) and the test receiver. Guidelines for a successful filter design are given, and components for a 5-kW rectifier prototype are selected. Furthermore, formulas for the estimation of the quasi-peak detector output based on the LISN output voltage spectrum are provided. The damping of filter resonances is optimized for a given attenuation in order to facilitate a higher stability margin for system control. Furthermore, the dependence of the filter input and output impedances and the attenuation characteristic on the inner mains impedance are discussed. As experimentally verified by using a three-phase common-/Differential-Mode separator, this procedure allows accurate prediction of the converter DM conducted emission levels and therefore could be employed in the design process of the rectifier system to ensure compliance to relevant EMC standards

Reproducibility and Uncertainty of Conducted Emission Measurements for Adjustable-Speed Electrical Power Drive Characterization

This paper deals with the estimation of systematic and random contributions that could influence the measurement of conducted emissions by adjustable-speed electrical power drive systems. Aside from the uncertainty due to the measurement chain, the electromagnetic compatibility test arrangement was considered as a possible source of uncertainty since it could compromise both the result reliability and the compliance/noncompliance of a given apparatus. In order to completely identify all the uncertainty components, tests were carried out by varying a number of influencing configuration parameters. Their effects on the measurement results were evaluated for the most common inverter modulation techniques, and the measurement reproducibility was evaluated

The special features of certifying open test sites for tests on technical equipment for electromagnetic compatibility

The particular features of estimating the attenuation of open test sites in electromagnetic compatibility tests are considered. It is shown by calculation that existing indirect methods of certification do not ensure reliable results. It is proposed to estimate the reflection coefficient of the screening plane, which defines the attenuation of the site.

Phase stirring of electromagnetic field to test the susceptibility of electronic equipment at lower frequencies

To guarantee the electromagnetic compatibility (EMC) of electronic equipment, their susceptibility to electromagnetic fields has to be quantified and compared to standardized immunity limits. The equipment's susceptibility is quantified by immersing it in an electromagnetic field of a known magnitude. The field magnitude is progressively increased until the equipment functioning is disturbed. However, the equipment's susceptibility also depends on the perturbation field polarization. Consequently, rigorous EMC tests require the analysis of different coupling configurations between the equipment under test (EUT) and the perturbation field. Knowing that the polarization of the field is predetermined by the test configuration, the EUT must be successively placed in different orientations inside the EMC test facilities. This paper studies the possibility of generating, in the lower frequencies, electromagnetic fields of variable polarization in order to test an EUT according to different field polarizations without moving it. The principle is studied in a three-dimensional TEM cell which is a variant of multi-plate TEM cells. The method consists of simultaneously feeding several strip lines of the cell to obtain a resultant electromagnetic field of variable polarization over time. The objective being to test the immunity of equipment independently of orientation, the control of the field magnitude is discussed.

Measured Response of Local, Mid-range and Far-range Discontinuities of Large Metal Groundplanes using Time Domain Techniques

Abstract. This work describes a method to detect and to quantify any local or mid-range discontinuity on extended flat metal planes. Often these planes are used for antenna calibration (open area test site - OATS) or the plane could be the ground of a semi-anechoic chamber used in Electromagnetic Compatibility (EMC) testing. The measurement uncertainty of antenna calibration or EMC testing depends on the groundplane's quality, which can be accessed using this method. A vector network analyzer with time-domain option is used to determine the complex-valued input scattering parameter S11,F of an aperture antenna in a monostatic setup. S11,F contains the information desired about the discontinuities and is measured in the frequency domain with high dynamic range. But only after a linear filtering utilizing the Chirp-Z-Transform the obtained time-domain signal S11,T evidence of local and mid-range discontinuities.

정지궤도 통신위성의 원격측정명령처리기 성능검증모델 전자파환경시험

This paper introduce electromagnetic environmental requirements, test procedures and test results for the Command Telemetry Unit(CTU), which is engineering qualification model for communication satellite in geostationary earth orbit. Also, through debugging of the CTU during the Electro Magnetic Compatibility(EMC) tests, this paper evaluates characteristics of noise generated by the CTU. It is also obtained that better EMC performance can be acquired by improving electrical power converter module of the CTU.