scholarly journals Reconstruction of PC Display from Common-Mode Noise Emitting on Electrical Power Line

2019 ◽  
Vol 9 (11) ◽  
pp. 2328
Author(s):  
Triet Nguyen-Van ◽  
Masakatsu Senda

This paper presents a method for reconstruction of a personal computer (PC) display image from common-mode noises coupling with monitor signals on a PC power cable. While the signal cable, which connects the PC and the monitor, is usually near the user, the power cable is connected to the outside electrical network of the office or the building. Thus, the power cables may become dominant gateways and/or antennas for emission and conduction of the common-mode noise, which may lead to a serious security issue. The measured common-mode was found to include both the monitor signal and undesired beats, which were caused by step responses of the signal and conceal the meaningful information. The original monitor signal was then calculated by excluding the beats, which could be measured by using standard up-step and down-step responses, from the measured common-mode noise and using an inverse function of the noise current level. The experimental results show that the beats were removed almost completely from the noise waveform for a monochromatic image. Alphabetic character strings, each of which were composed of, at most, 9 × 9 dots, were confirmed to be reconstructed clearly both in the monitor resolutions of 800 × 600 pixels and 1280 × 1024 pixels from the common-mode noise.


Frequenz ◽  
2020 ◽  
Vol 74 (7-8) ◽  
pp. 263-270
Author(s):  
Cao Zeng ◽  
Xue Han Hu ◽  
Feng Wei ◽  
Xiao Wei Shi

AbstractIn this paper, a tunable balanced-to-balanced in-phase filtering power divider (FPD) is designed, which can realize a two-way equal power division with high selectivity and isolation. A differential-mode (DM) passband with a steep filtering performance is realized by applying microstrip stub-loaded resonators (SLRs). Meanwhile, six varactors are loaded to the SLRs to achieve the center frequency (CF) and bandwidth adjustment, respectively. U-type microstrip lines integrated with stepped impedance slotline resonators are utilized as the differential feedlines, which suppress the common-mode (CM) intrinsically, making the DM responses independent of the CM ones. A tuning center frequency from 3.2 to 3.75 GHz and a fractional bandwidth (12.1–17.6%) with more than 10 dB return loss and less than 2.3 dB insertion loss can be achieved by changing the voltage across the varactors. A good agreement between the simulated and measured results is observed. To the best of authors' knowledge, the proposed balanced-to-balanced tunable FPD is first ever reported.



Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 466
Author(s):  
Pawel Szczepankowski ◽  
Natalia Strzelecka ◽  
Enrique Romero-Cadaval

This article presents three variants of the Pulse Width Modulation (PWM) for the Double Square Multiphase type Conventional Matrix Converters (DSM-CMC) supplying loads with the open-end winding. The first variant of PWM offers the ability to obtain zero value of the common-mode voltage at the load’s terminals and applies only six switches within the modulation period. The second proposal archives for less Total Harmonic Distortion (THD) of the generated load voltage. The third variant of modulation concerns maximizing the voltage transfer ratio, minimizing the number of switching, and the common-mode voltage cancellation. The discussed modulations are based on the concept of sinusoidal voltage quadrature signals, which can be an effective alternative to the classic space-vector approach. In the proposed approach, the geometrical arrangement of basic vectors needed to synthesize output voltages is built from the less number of vectors, which is equal to the number of the matrix converter’s terminals. The PWM duty cycle computation is performed using only a second-order determinant of the voltages coordinate matrix without using trigonometric functions. A new approach to the PWM duty cycles computing and the load voltage synthesis by 5 × 5 and 12 × 12 topologies has been verified using the PSIM simulation software.



Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 282
Author(s):  
Seon-Ik Hwang ◽  
Jang-Mok Kim

The common-mode voltage (CMV) generated by the switching operation of the pulse width modulation (PWM) inverter leads to bearing failure and electromagnetic interference (EMI) noises. To reduce the CMV, it is necessary to reduce the magnitude of dv/dt and change the frequency of the CMV. In this paper, the range of the CMV is reduced by using opposite triangle carrier for ABC and XYZ winding group, and the change in frequency in the CMV is reduced by equalizing the dwell time of the zero voltage vector on ABC and XYZ winding group of dual three phase motor.



2007 ◽  
Author(s):  
Zdzislaw H. Klim ◽  
Marek Balazinski
Keyword(s):  


Author(s):  
Roger Slora ◽  
Stian Karlsen ◽  
Per Arne Osborg

There is an increasing demand for subsea electrical power transmission in the oil- and gas industry. Electrical power is mainly required for subsea pumps, compressors and for direct electrical heating of pipelines. The majority of subsea processing equipment is installed at water depths less than 1000 meters. However, projects located offshore Africa, Brazil and in the Gulf of Mexico are reported to be in water depths down to 3000 meters. Hence, Nexans initiated a development programme to qualify a dynamic deep water power cable. The qualification programme was based on DNV-RP-A203. An overall project plan, consisting of feasibility study, concept selection and pre-engineering was outlined as defined in DNV-OSS-401. An armoured three-phase power cable concept assumed suspended from a semi-submersible vessel at 3000 m water depth was selected as qualification basis. As proven cable technology was selected, the overall qualification scope is classified as class 2 according to DNV-RP-A203. Presumed high conductor stress at 3000 m water depth made basis for the identified failure modes. An optimised prototype cable, with the aim of reducing the failure mode risks, was designed based on extensive testing and analyses of various test cables. Analyses confirmed that the prototype cable will withstand the extreme loads and fatigue damage during a service life of 30 years with good margins. The system integrity, consisting of prototype cable and end terminations, was verified by means of tension tests. The electrical integrity was intact after tensioning to 2040 kN, which corresponds to 13 000 m static water depth. A full scale flex test of the prototype cable verified the extreme and fatigue analyses. Hence, the prototype cable is qualified for 3000 m water depth.







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