Line Impedance Stabilization Network Research Articles

A Compact, Single Stage, >1 kV Medium-Voltage Line Impedance Stabilization Network

A Compact, Single Stage, >1 kV Medium-Voltage Line Impedance Stabilization Network

Conducted Emission signal-based identification and real-time hardware security with deep learning

In advancing electronic systems, the replicable nature of devices used in critical environments raises concerns regarding system security. It is of great importance to establish security by identifying electronic devices and computers based on their unique electrical signals, rather than assigning an artificial identity number for security purposes. This paper presents a methodology for identifying electronic devices by capturing their Conducted Emission signal over cables using a Line Impedance Stabilization Network (LISN), followed by applying deep learning techniques. After the extraction of the identities specific to each device based on their electronic characteristics, the establishment of security has been accomplished through these characteristics. The identification process was analyzed through theoretical approaches, and signals were examined by acquiring simulation-based data. After performing the analyses, the data was converted into spectrograms for training the deep learning model using the Conducted Emission signals, and a Convolutional Neural Network (CNN) was used due to its recognized efficacy in handling two-dimensional data formats like spectrogram for the deep learning algorithm. It was observed that with an accuracy of 99.9%, identification was achieved in deep learning results utilizing the data obtained through simulations. Real-time data from 15 devices was collected after training the system with simulation-based data, demonstrating a 99.8% accuracy in accurately identifying the devices. Furthermore, the developed deep learning model was deployed on an Embedded Linux edge device, tested within the system for one day, and achieved an average accuracy of 99.54% in accurately identifying registered devices.

Comparison of conducted emissions due to electric vehicle charging processes under isolated and on-line conditions in the 9–500 kHz frequency range

This paper aims at comparing the conducted emissions generated by Electric Vehicle Charging Processes (EVCPs) under isolated and on-line conditions in the frequency and time domains, covering the 9–500 kHz frequency range. The isolated conditions correspond to the use of a Line Impedance Stabilization Network (LISN), whereas measurements in the Low Voltage (LV) grid where the EV is connected are referred to as on-line conditions. Regarding the frequency analysis, the results lead to conclude that different amplitude and spectral features of the Non-Intentional Emissions (NIEs) are measured depending on the measurement conditions, registering higher-amplitude NIEs when the measurements are conducted in the LV grid. Moreover, the paper also shows that the spectral characteristics of the NIEs correspond to tonal and narrowband emissions at specific frequencies in the 9–150 kHz frequency range, while background noise with low-amplitude emissions (in the case of isolated conditions) and colored noise (in the case of on-line conditions) are reported in the 150–500 kHz band. In the time domain, a periodic time-dependent behavior within the fundamental cycle of the mains (20 ms) is reported in all the analyzed cases, except for the tonal emissions with oscillating central frequency generated by a specific EV model. The time variability between both measurement configurations only differs by more than 3 dB for three out of the twelve analyzed EVCPs, where a higher variability is observed if the measurements are carried out using a LISN. As a conclusion, considering the differences in the frequency and time characteristics of the NIEs under isolated and on-line conditions, evaluating the emissions generated by EVCPs might lead to an underestimation of the NIEs in real LV grids.

Enhanced the Efficiency of Electronics Circuit by using Line Impedance Stabilization Network

A Line Impedance Stabilization Network (LISN) is a crucial tool in the field of electromagnetic compatibility (EMC) testing and measurement. Its primary purpose is to ensure that conducted emissions from electrical and electronic devices are accurately measured in a controlled and standardized manner. After both circuit simulation in LTSpice firstly input noise simulation without LISN in first circuit and after that second circuit simulation in which we simulate input noise simulation with LISN we reached on the final conclusion is that by stabilizing the impedance of the power supply line, LISNs help filter out external interference and noise, allowing for precise measurements of the emissions generated by the DUT. They provide a standardized impedance interface between the device under test (DUT) and the measuring equipment, ensuring consistent and repeatable EMC testing results. We get desired result after simulation when we analysis both circuit simulation in details we get 33% improvement in frequency, noise decreases in terms of frequency and we get 3% improvement in power at output in LISN applying circuit.

A Review on the Characteristics of Line Impedance Stabilization Network

A Line Impedance Stabilization Network (LISN) is an essential component in electromagnetic compatibility (EMC) testing and measurement. Its primary purpose is to provide a standardized interface between electronic devices, such as radios, computers, and other electrical equipment, and the power supply grid during conducted emissions testing. A LISN is designed to facilitate accurate and repeatable measurements of electromagnetic interference (EMI) generated by electronic devices when they are connected to the power supply grid. It serves as an essential tool for assessing the compliance of electronic equipment with EMC standards and regulations. A low-pass filter within the LISN helps remove high-frequency noise and disturbances from the power supply, allowing only the emissions of interest to pass through for measurement. a Line Impedance Stabilization Network (LISN) is a critical tool for EMC testing and measurement, providing a standardized and controlled interface between electronic devices and the power supply grid. It enables the assessment of conducted emissions from electronic equipment, helping manufacturers ensure their products comply with EMC regulations and minimizing the risk of interference with other devices and systems.

Passive CM Filter Configuration for a Multistage Grid-Tied Solid State Transformer

<bold xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">This work proposes a common mode (CM) filter configuration for a grid-tied two-stage AC/DC solid state transformer (SST). The proposed CM filter utilizes passive components along with the heat-sinks of the individual power converter stages to mitigate the overall conducted emissions (CE) injected by the SST system into the grid. The working principle of the proposed CM filter is analyzed and elucidated using CM equivalent circuit models. In addition to CE reduction with the proposed CM filter, it is also demonstrated that the heat-sinks of the SST system can be closer to ground-potential while being impedance grounded. The effectiveness of the proposed CM filter is validated by experimentally measuring the CE of the grid-tied SST system using a Line Impedance Stabilization Network (LISN).</b>

Integrated Common-Mode Filter for GaN Power Module With Improved High-Frequency EMI Performance

While the employment of wide bandgap (WBG) devices in high-frequency and high-voltage applications brings benefits such as reduced system size and improved efficiency, it aggravates the electromagnetic interference (EMI) issue due to fast switching. High-frequency EMI noise suppression relies mainly on the filter design, where the filter's performance is strongly affected by parasitics. Through analyzing the common-mode (CM) equivalent circuit of a half-bridge power module, this letter identifies the key parasitics that dominate the performance of a common-mode filter (CMF) at high frequencies. To minimize the parasitics, the concept of integrating the CMF inside the WBG power module package is developed to improve the noise attenuation. A π-type CMF is integrated with a half-bridge GaN-based power module as a prototype to validate the concept. Experiments are conducted by measuring the CM noise spectrum received by the line impedance stabilization networks (LISNs) from the hard switching of the designed power module under 70 V and 80 kHz. Comparing the measured results of the integrated CMF to the externally-added CMF, up to 50 dBμV more attenuation is achieved by the integrated CMF in the frequency range of 10 MHz to 100 MHz, verifying the theoretical analysis and the established CM equivalent circuit.

Elimination of CM Noise from SMPS Circuit using EMI Filter

The electronic devices are exposed to external electromagnetic signals that produce an unwanted signal called noise in the circuit, which causes electromagnetic interference [EMI] problems. It occurs in two modes: radiated mode and conducted mode. In the radiation mode, the shielding technique is used for radiation mode, in conduction mode filtering technique is used. The design of an EMI filter depends upon the type of noise generated by the Switched Mode Power supply circuit [SMPS]. The SMPS circuit used in this paper is a DC-DC power converter, the Boost converter is a step-up converter and Buck converter is step down converter are considered as equipment for generation of noise, the Line Impedance Stabilization Network [LISN]is used for generating the common output impedance to the power converters, the EMI filters are designed to eliminate noise generated by the circuits. There noise generated by this power converters is Common Mode [CM] noise and Differential Mode [DM] noise. The separation of noise from the equipment is done by using a noise separator. In this paper, CM noise generated by these power converters is eliminated by designing an EMI filter called an inductor filter and a PI filter. The comparison between the LC inductor filter and the PI filter for the boost and buck converters is observed. The PI filter has better performance characteristics when compared to the inductor filter for both SMPS circuits as per the Comité International Special des Perturbations Radioélectriques [CISPR] standards. This standard gives the conducted emission range for different electronic devices.

Broadband Modeling and Simulation Strategy for Conducted Emissions of Power Electronic Systems Up to 400 MHz

Energy efficiency is becoming one of the most important topics in electronics. Among others, wide band-gap semiconductors can raise efficiency and lead to shrinking volumes in power conversion systems. As different markets have regulations that require different designs, it is necessary to cope with a large variety of similar designs. By using effective modeling and simulation strategies, the efforts of building these variants can be diminished, and re-designs can be avoided. In this paper, we present a universally valid way to come to reasonable simulation results for conducted emissions of a power electronic system in the frequency range from 150 kHz up to 400 MHz. After giving an overview of the state-of-the-art, the authors show how to implement and set up a simulation environment for a gallium-nitride (GaN) power converter. It shows how to differentiate between important and not that important components for Electromagnetic Compatibility (EMC), how to model these components, the printed circuit board, the load, and the setup, including the Line Impedance Stabilization Networks (LISNs), etc. Multiport S-parameter strategies as well as vector fitting methods are employed. Computational costs are kept low, and all simulations are verified with measurements; thus, this model is valid up to 400 MHz.

Power impact and electromagnetic disturbances of different lighting modes from spot LED lamp

Light-emitting diode (LED) lamp has been widely used in recent years for lighting systems due to its environmental friendliness, long life, low power consumption and high efficiency. However, LED lamps are sources of harmonic pollution due to AC/DC conversion by rectifier diodes which results in poor power quality. LED lamps research focuses on improving the power factor (PF) and reducing current harmonics.In this article, we present the study of the harmonics of the current generated by two Spot-type LED lamps of the same brand and of different power. We took the following harmonics measurement cases: 6 W and 12 W lamps, the two lamps in parallel, for the different lighting modes, we need to make measurements for the three lighting modes: white lighting, colored lighting and mixed lighting between white and colored. Then, the electromagnetic disturbances conducted in common mode and in differential mode, using the Line Impedance Stabilization Network (LISN), were determined.

Supraharmonic Emissions from DC Grid Connected Wireless Power Transfer Converters

Power converters for wireless power transfer (WPT) and, in general, for electrical vehicle charging are evolving in terms of nominal power and performance, bringing along non negligible emissions in the supraharmonic range (2 kHz to 150 kHz). The large installed power and the high concentration with a relatively short separation distance can be addressed by feeding the converters through a DC grid for better dynamic response and lower impedance. The prediction of conducted emissions in real supply conditions requires carrying out measurements with low impedance values, lower than those available in line impedance stabilization networks (LISNs) for AC grids. This work proposes an approach to extrapolate converter emissions in an ideal 0 Ω condition, that together with the input impedance curve (determined by a least mean square approach) form a Norton equivalent circuit of the converter. The interaction of the converters with the DC grid and superposition of emissions can be then thoroughly evaluated by means of a general ladder grid scheme to which the Norton equivalents are connected. Such a grid model is suitable for Monte Carlo simulation aimed at assessing the degree of compensation between sources of emissions and the overall network distortion. Results using a Simulink model are provided considering emissions aggregation and compensation under random phase conditions for the following cases: close-by and separated sources (5 m and 100 m cable separation, respectively); increased number of sources studying scenarios with 3 and 10 sources; and using different resolution bandwidth values (200 Hz and 500 Hz) against a random change of the frequency of the emission components.

Evaluation of the Common Mode and the Differential Mode Components From Conducted Emission Measurements

The design of the power supply electromagnetic interference filter needed to mitigate the conducted emission of electronic modules can be performed best if the magnitude of the common mode (CM) and that of the differential mode (DM) interference are known. In common test setups, the two terms can be obtained from the signals measured at the line impedance stabilization networks (LISNs) output ports using DM and CM rejection networks or through the postprocessing of the output signals in the time domain. Both these approaches rely on the perfect matching of the LISNs internal filters, which is not realistic. Indeed, the LISNs mismatch allow the DM to be measured as CM and vice versa. In this work, the influence of the LISNs mismatch on the separation of CM and DM is investigated and a fast and accurate method to do that is proposed.

Analyzing the Influence of Imbalanced Two- or Three-Wire VHF LISN on Radiated Emissions from AC Cables

This article investigates using imbalanced two- and three-wire terminations for ac main cables, as suggested by the standard group. These terminations provide the basis for a new line impedance stabilization network (LISN) whose objective is to improve test repeatability between labs while also providing better estimation of real-world emissions. Standard balanced LISNs do not reproduce the imbalanced terminations seen in practice. An imbalanced two- or three-wire very high-frequency LISN was built, which can handle up to 15 A on each line. The LISN operates from 30 to 200 MHz and provides greater than 50-dB isolation between the input and output. The imbalanced termination allows the device to create a specified degree of conversion from differential-mode to common-mode current, which can increase radiated emissions. This conversion was evaluated to be as high as 12 dB in measurements of a power line communication device. 3-D full-wave simulations of two- and three-wire applications demonstrate that the radiated emissions from the prototype LISN and the ideal imbalanced termination are nearly equal. The new LISN was further evaluated to show promise for improving measurement reproducibility, reducing the standard compliance uncertainty by 6 dB in this study, from 15.5 dB in CISPR 16-4-1 to 9.5 dB with the LISN.

Variability Caused by Setup and Operating Conditions for Conducted EMI of Switched Mode Power Supplies Over the 2–1000 kHz Interval

The measurement of conducted emissions of switched mode power supplies (SMPSs) is discussed for the 2–1000-kHz frequency range, analyzing variability caused by setup elements and test conditions. The tested SMPSs have 12-VDC output and about 20-W nominal power. They are fed by a controlled ac power supply, instead of mains, through a line impedance stabilization network and various loading levels are applied. Identified causes of variability (supply voltage and frequency variations, thermal stabilization influencing internal mechanisms of emissions) indicate a relevant impact on the spread of measured conducted emissions, ranging from a fraction of decibels to about 10 dB (sample standard deviation). Such phenomena represent a cause first of all of systematic error, but also of increased uncertainty. No EMC standards are known to take them into account, nor the scientific literature reports extensive quantification, as in the present case. The shift of the line spectrum of emission consequential to a mains frequency change revealed to be exploitable also for better identification of internal sources of emission.

Calibration of Line Impedance Stabilization Networks / Artificial Mains Networks in Accordance with CISPR 16-1-2 Ed 2.1 2017-11

This paper describes a measurement procedure developed by the Standards and Calibration Laboratory (SCL) for measuring the parameters of single phase 50 Ω//(50 μH + 5 Ω) V-network type line impedance stabilization networks (LISN) or artificial mains networks (AMN) specified in the international standard CISPR 16-1-2, which are the impedance at the equipment-under-test (EUT) port, the isolation between the power port and the receiver port, and the voltage division factor between the EUT port and the receiver port. The corresponding measurement models and evaluation of measurement uncertainties are presented. The characterization method of in-house developed adapters for BS1363 type plug and socket is also presented.

EMI Attenuation in a DC–DC Buck Converter Using GaN HEMT

A dc-dc buck converter using gallium nitride (GaN) high electron mobility transistors (HEMTs) is experimentally investigated at the discontinuous-current-mode (DCM) and the triangular-current-mode (TCM) operations. The objective of this article is to specify the power conversion efficiency and attenuation of common-mode (CM) and differential-mode (DM) noise voltage, measured at the line impedance stabilization network (LISN) for the compared control strategies. Zero-voltage switching achieved for the TCM operation improves efficiency with reference to the DCM operation. However, significant attenuation of electromagnetic interference (EMI) spectra is obtained for TCM operation with capacitive snubber. Sizing of capacitor snubber dependent on parasitic inductances of the commutation circuit and rapid switching of GaN HEMTs are illustrated.

Experimental Measurement of Conducted Emissions Generated by Static Converters in Common and Differential Modes

The commutation of semiconductors and their interactions with parasitic elements linked to the environment is known to be the main source of interferences conducted in power electronic converters. Thus, identifying these sources of interferences in commutation cells and determining the level of these conducted emissions generated in energy conversion systems presents a major challenge for designers. In this work, a study of the electromagnetic interferences (EMI) generated by the association of serial rectifier-chopper connected to a Line Impedance Stabilization Network (LISN) is proposed, in which a determination of these interferences is presented in both common and differential modes. All simulations are carried out using the LT-spice software and the results obtained are validated by experimental measurements realized at APELEC laboratory (University of Sidi Bel-Abbes, Algeria).

Black-Box Modelling of Low-Switching-Frequency Power Inverters for EMC Analyses in Renewable Power Systems

Electromagnetic interference (EMI) from renewable power systems to the grid attracts more attention especially in the low-frequency range, due to the low switching frequency of high-power inverters. It is significantly important to derive EMI models of power inverters as well as to develop strategies to suppress the related conducted emissions. In this work, black-box modelling is applied to a three-phase inverter system, by implementing an alternative procedure to identify the parameters describing the active part of the model. Besides, two limitations of black-box modelling are investigated. The first regards the need for the system to satisfy the linear and time-invariant (LTI) assumption. The influence of this assumption on prediction accuracy is analysed with reference to the zero, positive and negative sequence decomposition. It is showing that predictions for the positive/negative sequence are highly influenced by this assumption, unlike those for the zero sequence. The second limitation is related to the possible variation of the mains impedance which is not satisfactorily stabilized at a low frequency outside the operating frequency range of standard line impedance stabilization networks.

Modeling of line impedance stabilization network impedance characteristic based on genetic algorithm

The line impedance stabilization network (LISN) is commonly used to measure the conducted electromagnetic interference (EMI) noise produced by electronic equipment. In order to improve the measurement accuracy of the conducted EMI noise, the characteristics of the LISN should be verified and calibrated, such as impedance and voltage division factor. However, the parasitic parameters of capacitance and inductance are critical to the performance of the LISN. In this paper, the high-frequency model of the LISN is proposed based on the topology and parasitic parameters. The impedance of the LISN is obtained from 150 ​kHz to 30 MHz based on scattering parameters method and vector network analyzer (VNA). The parasitic parameters of capacitance and inductance are extracted by employing the elite genetic algorithm (EGA), LISN topology and impedance. The voltage division factor and impedance of R&S LISN ENV216 is obtained and calculated by employing the proposed method, which verify the proposed method effectiveness. The work will contribute to the further design and calibration of the LISN, and improve the conducted EMI noise measurement accuracy.

Automatic PCB Layout Optimization of a DC-DC Converter Through Genetic Algorithm Regarding EMC Constraints

This paper proposes an optimization approach for an automatic buck converter printed circuit board (PCB) design regarding the electromagnetic compatibility (EMC) constraints. The proposed solution is based on the combination of a genetic algorithm (GA) and a Dijkstra algorithm to generate the different PCB layout designs. Afterwards, a numerical modeling approach, taking into account all the stray elements, is proposed to obtain an accurate equivalent circuit for the PCB layout using ANSYS Q3D software. Subsequently, the complete behavior of the converter is simulated within SIMPLORER, including the electrical models of the components, the Line Impedance Stabilization Network (LISN) module as well as the PCB layout model. This aims to compute the conducted disturbances such as the common and the differential mode voltages. Then, this approach is implemented in an optimized process to reach the optimal geometry for the printed circuit board layout with the lowest parasitic effect to fit the EMC requirements. Finally, measurements are performed, and the optimization results are presented and investigated, in comparison with reference PCB layout to assess the efficiency of the proposed methodology.