Improvement Of Electromagnetic Compatibility Research Articles

Improvement of electromagnetic compatibility and efficiency of power supply circuits of electric arc furnaces in nonlinear asymmetric modes

AC steel arc furnaces are the most powerful units connected to the electrical grid, the operating mode of which is dynamic, asymmetrical and non-linear. That is why these furnaces cause the entire possible range of negative effects on the quality of electricity in the grid, in particular, fluctuations, asymmetry and non-sinusoidal voltage.Known proposals for improving the electromagnetic compatibility of electric arc furnaces are mainly focused on eliminating the consequences of their ne­gative impact on the power grid.The proposed approach and the corresponding technical solution are aimed at reducing the level of generation of a negative factor and at the same time reduce fluctuations, asymmetry and non-sinusoidal voltage. This result is obtained due to the fact that the proposed solution takes into account the peculiari­ties of the range of modes natural for arc furnaces. Optimal for such consumers is the use of a constant current power supply system I=const in the range of modes from operational short circuit to maximum load and the system U=const in the whole other range of modes. The implementation of such a system is carried out on the basis of a resonant converter «constant current – constant voltage».Studies have found that the use of such a power supply system, in comparison with the traditional circuit, makes it possible to reduce the non-sinusoidal voltage in a low-power grid from 3.2 % to 2.1 % and the unbalance coefficient from 3.66 to 1.35 %. Previously published data on a significant reduction in voltage fluctuations was also confirmed.The positive effect of such a system on the energy performance of the furnace itself is shown, manifes­ted in an increase in the arc power by 12.5 %, and the electrical efficiency by 5.1 %. This improves the productivity and efficiency of electric arc furnaces

EMC improvement for high voltage pulse transformers by pareto-optimal design of geometry structure based on parasitic analysis and EMI propagation

High voltage pulse transformers have an essential role in pulsed power systems and power conversion applications. Improving the electromagnetic behavior of such devices leads to better efficiency and low-level electromagnetic interference (EMI) noise propagation in systems. In this paper, a high voltage pulsed power system is considered and analyzed to improve the electromagnetic compatibility (EMC). The new generation of pulsed power systems that use SiC and GaN fast switches in capacitor charger power electronic circuit, face far more EMI challenges. Moreover, in this paper, the EMI propagation paths in the pulsed power system are realized and analyzed. The EMI noise level of the system is obtained and compared to the IEC61800-3 standard. To improve the EMC, the parasitic parameters of the transformer, as the main path of EMI circulation, are optimized to block the EMI propagation in the pulsed power system. For this aim, the parasitics are modeled and calculated with a novel and accurate energy distribution model. Then, by defining a cost function the geometry structure of the transformer is optimized to lower the parasitics in the system. Three pareto-optimal techniques are investigated for the cost function optimization. The models and results are verified by 3D-finite element method (FEM) and experimental results for several given scenarios. FEM and experimental verifications of this model, make the model suitable for any desirable design in any pulsed power systems. Finally, the EMI noise level of the system after optimization is shown and compared to the IEC61800-3 standard.

Analysis and design of defected ground structure for EMC improvement in mixed‐signal transceiver modules

In this research, the return path discontinuity (RPD), located under the power amplifier (PA) substrate, of X-band transceiver module (Base), mounted on a four-layer printed circuit board (PCB), is investigated to improve the signal integrity by reducing the difference in the reference potential. This study is performed by initially employing the wirebond method, through the assessment of both numbers and sizes of bondwires by advanced design system (ADS). Six bondwires of 25 µm are added, producing an improvement of 6.82 dB for the reflection coefficient and 1.19 dB for the isolation and insertion loss. For further improvement, spiral shape defected ground structure (DGS) is implemented in the inner ground layer (layer 2) without using bond wires. The DGS simulation results illustrate an improvement of 3 dB for S11 and 0.6 dB for S12. To improve the electromagnetic compatibility (EMC), the authors propose combination and integration of both wirebond and DGS methods, called wirebond–DGS method, which results in an improvement of 11.86 dB for S11, 1.34 dB for S12 and S21, and 12.03 dB for S22. Finally, the wirebond–DGS RF module was fabricated and the measurement results exhibit an improvement of 8.07 dB for S11 and 9.39 dB for S22 in comparison with the fabricated Base module. In addition, 0.53 dB improvement for both S12 and S21 is also achieved.

EMC improvement of an ECH power supplies system at TCV

Three RHVPSs (regulated high voltage power supplies, 85kV/80A/2s) are installed and have been operated at the Swiss Plasma Center for more than 20 years. Each RHVPS supplies a cluster of three gyrotrons. Two clusters are composed of diode-type gyrotrons operating at the second harmonic of the TCV electron-cyclotron frequency (X2, 82.74GHz); the third is a cluster of triode-type gyrotrons operating at the third harmonic (X3, 118GHz). During the design and installation period, grounding (earthing) was primarily considered to the point of view of safety. EMC (electro magnetic compatibility) was not a major consideration; so, the ECH plant operation produced strong electromagnetic interference with other tokamak's systems. This article focuses on the EMC problems inherent to power converters. The mechanism by which these converters influence their environment is explained. Solutions to minimise the emission of interference are given. Finally, first results of real-time X3 RF power tuning during TCV shots are shown. EMC improvements make possible extended TCV heating scenarios.

VLSI Implementation of 8051 MCU with Decoupling Capacitor for IC-EMC

In recent years, several new methods for IC-level electromagnetic compatibility (EMC) testing have been introduced. Therefore, a handy vehicle for IC-EMC testing is required to validate the effectiveness of the new IC-EMC testing methods. This paper proposes an 8051 MCU for IC-EMC testing platform with in-system programming (ISP) and decoupling capacitor (decap) functions. In order to reduce the EMI and improve the EMC properties for the 8051 MCU, decoupling capacitors (decaps) are added to the integrated circuit (IC) design flow. Chip-level design and fabrication technology are fundamental and cost-effective solutions to this issue. A cell-based design flow is used for chip implementation; specifically, TSMC 90-nm technology is used to implement the present chip via the National Chip Implementation Center. This study will implement two 8051 MCU chips: one that internally comprises a large number of decaps, and another that comprises no decaps. We also implemented an IC-EMC testing platform composed of a multifunction test board and several off-board probes that were fabricated according to IEC 61967 and IEC 62132 standards. The platform demonstrates a method for using the proposed two 8051 chips in EMC testing, and we reveal the results of its EMC performance. Finally, this study simulates the EMC properties, compares the two 8051 MCU chips, conducts static or dynamic analyses for the chips in a power network, and measures the EMC improvements.

Новые принципы построения радиоэлектронной аппаратуры СВЧ-диапазона с использованием радиофотонной технологии

There are highlighted fundamental and practical advantages referred to introduction of the new interdisciplinary scientific and technological direction, that is, microwave photonics, in modern and perspective radio means of a dual purpose. The main advantages consist in increase of operating frequency to terahertz range, expansion of a processing band to several gigahertz, improvement of electromagnetic compatibility and mass-volume characteristics. A classification of the component base of microwave photonics is proposed, the modern level of world development of microwave photonics with emphasis on its second stage, which is integrated microwave photonics, is analyzed. The works in the field of microwave photonics that have been performed or being conducted by research groups at Moscow Technological University, including results of modeling and research projects, training, and the nearest tasks of the established Scientific and Technological Center «Integrated Microwave Photonics» are briefly described.

Study on design and electro magnetic compatibility of high-power pulse driver

A kind of high-power pulse driver is designed to drive semiconductor laser. The circuit consists of three parts: generator of pulse signal, power amplifier of pulse signal and storage circuit controlled by metal-Oxide-semiconductor field-effect transistor (MOSFET). According to the experimental results, this kind of high-power pulse driver well restrained the pulse spike and overshoot by proper design, better choice of components and improvement of electro magnetic compatibility (EMC). The circuit can output pulse signal with better quality, which provides qualified driving signal to laser diode. The pulse width is under 50 ns and the output ranges from 10 A to 50 A.

Exploring Types of Instabilities in Switching Power Converters: the Complete Bifurcation Analysis

This paper is dedicated to investigation of different types of instabilities in switching power converters under peak current mode control on the basis of improved discrete-time model. The general aspects of construction of complete bifurcation diagrams are supplemented by examples of possible practical applications in the field of power electronics. It is demonstrated that the data obtained from the properties of numerically calculated unstable periodic regimes can be efficiently utilized to estimate some practically relevant parameters of the converter. Special attention is paid to uncommon nonlinear effects occurring in the dynamics of boost converter as the compensation ramp is applied. The possibilities of application of different chaotic modes to the improvement of electromagnetic compatibility are defined in terms of proved robustness of chaos. DOI: http://dx.doi.org/10.5755/j01.eee.20.5.7103

Suppression measures for electromagnetic emission interference in low frequency range in hybrid electric vehicles

Limit–exceeding problems exist in electric field and magnetic field emission level in a type of hybrid electric vehicles. Characteristics of main electromagnetic interference source in the vehicles are analysed, production mechanism of radiated electric filed and magnetic field in the whole vehicle is discussed and the conclusion that the main interference sources of whole vehicle electromagnetic emission are three–phase working current of drive motor and electric motor controller is cleared up. Additionally, considering the properties of interference source, corresponding suppression measures for interference are proposed and applied. In the end, comparison validations with experiments are made to show that the whole vehicle electric field in low frequency range and the level of magnetic emission can be decreased by the suppression measures applied. The measures can also provide a reference for electromagnetic compatibility improvement in other hybrid electric vehicles.

Reduced Conductive EMI in Switched-Mode DC–DC Power Converters Without EMI Filters: PWM Versus Randomized PWM

This paper addresses improved electromagnetic compatibility (EMC) in switched-mode power converters (SMPCs), without using electromagnetic interference (EMI) filters. A practical solution is proposed for minimizing conductive EMI in a pulsewidth modulated (PWM), and random PWM dc-dc power converters. A comparative investigation is performed into the use of different random modulation schemes (driven by the DSP-2 board with the TMS320C32) as against the normal PWM. The effectiveness of randomization on spreading those dominating frequencies that normally exist in constant frequency PWM schemes is evaluated by power spectral density (PSD) estimations in the low-frequency range. Some parasitical- and topology-based EMI sources in devices are presented and frequency analysis is shown by using the discrete Fourier transform (DFT). SPICE simulations are also used to verify practical solutions for eliminating negative EMI sources and achieving EMC improvements. Finally, levels of conductive EMI are estimated with DFT, and experimentally verified to comply with the CISPR 25 (or EN 55025) regulations. Moreover, it is clearly shown, that limited speed PWM driving of the power switches with appropriate snubber circuits guarantees reduced conductive EMI. When considering the price and high EMC, in the final solution the power converter is driven by the mu-controller PIC16F876 with limited numerical and peripheral capabilities, where only normal PWM and randomized PWM can be implemented

Integrated Telecommunication Systems for Determining Parameters of Mobile Objects, Control, and Communication

An approach to solving the problem of provision of radar cover of the adjacent areas via the control and communication means in the conditions of the scarcity of the frequency resource and improvement of electromagnetic compatibility has been illustrated. It has been shown that this problem can be solved through the use of noise-like signals at the transmitting side and through their processing in spin detectors at the time of reception. A method of transmitting and detecting a noise-like signal has been developed and a flow diagram of the device, implementing this method, is presented.