A Low Frequency Sinusoidal Voltage Source

1950 ◽  
Vol 21 (4) ◽  
pp. 302-303
Author(s):  
Louis A. Rosenthal
2018 ◽  
Vol 12 (1) ◽  
pp. 98-109 ◽  
Author(s):  
Adolfo Dannier ◽  
Gianluca Brando ◽  
Ivan Spina ◽  
Diego Iannuzzi

Objective:This paper analyses the Modular Multilevel Converter (MMC) topology, where each individual Sub Module (SM), in half bridge configuration, is directly fed by an elementary electrochemical cell.Methods:The aim is to investigate how the reference voltages influence the cells currents waveforms, determining how the active powers and the losses are distributed among the cells. Considering a 2-level Voltage Source Inverter (VSI) topology working in the same conditions, the ratio between the MMC total cells losses and VSI total cells losses is calculated. After showing the system architecture and mathematical model, the cells current waveform investigation is presented and detailed both for triangular and sinusoidal voltage reference waveform.Results:Finally, the results are critically discussed with particular focus on the comparison between the MMC and the VSI topologies.


Electronics ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 60
Author(s):  
Mario Ponce-Silva ◽  
Daniel Salazar-Pérez ◽  
Oscar Miguel Rodríguez-Benítez ◽  
Luis Gerardo Vela-Valdés ◽  
Abraham Claudio-Sánchez ◽  
...  

The main contribution of this paper is to show a new AC/DC converter based on the rearrangement of the flyback converter. The proposed circuit only manages part of the energy and the rest is delivered directly from the source to the load. Therefore, with the new topology, the efficiency is increased, and the stress of the components is reduced. The rearrangement consist of the secondary of the flyback is placed in parallel with the load, and this arrangement is connected in series with the primary side and the rectified voltage source. The re-arranged flyback is only a reductive topology and with no magnetic isolation. It was studied as a power supply for LEDs. A low frequency averaged analysis (LFAA) was used to determine the behavior of the proposed circuit and an equivalent circuit much easier to analyze was obtained. To validate the theoretical analysis, a design methodology was developed for the re-arranged flyback converter. The designed circuit was implemented in a 10 W prototype. Experimental results showed that the converter has a THDi = 21.7% and a PF = 0.9686.


2021 ◽  
Vol 11 (15) ◽  
pp. 6920
Author(s):  
Oldřich Coufal

Two infinitely long parallel conductors of arbitrary cross section connected to a voltage source form a loop. If the source voltage depends on time, then due to induction there is no constant current density in the loop conductors. It is only recently that a method has been published for accurately calculating current density in a group of long parallel conductors. The method has thus far been applied to the calculation of steady-state current density in a loop connected to a sinusoidal voltage source. In the present article, the method is used for an accurate calculation of transient current using transient current density. The transient current is analysed when connecting and short-circuiting the sources of sinusoidal, constant and sawtooth voltages. For circular cross section conductors, the dependences of maximum current density, maximum current and the time of achieving steady state on the source frequency, the distance of the conductors and their resistivity when connecting the source of sinusoidal voltage are examined.


2020 ◽  
Vol 95 (6) ◽  
pp. 065503
Author(s):  
Oldřich Coufal ◽  
Lukáš Radil

Author(s):  
I. V. Shestakov ◽  
N. R. Safin

The paper introduces the results of mathematical simulation of the operating modes of an asynchronous motor when powered by a sinusoidal voltage source and a width-modulated voltage pulse source. The study shows the possibilities of increasing the energy efficiency of an asynchronous electric drive. Findings of research show the feasibility of studying the switching of the motor power source from a pulse width-modulated voltage to a sinusoidal voltage source in the nominal operating mode in order to increase the energy efficiency of the electric drive


2021 ◽  
pp. 2150050
Author(s):  
Mutaz Y. Melhem ◽  
Christiana Chamon ◽  
Shahriar Ferdous ◽  
Laszlo B. Kish

Recently, several passive and active attack methods have been proposed against the Kirchhoff–Law–Johnson–Noise (KLJN) secure key exchange scheme by utilizing direct (DC) loop currents. The DC current attacks are relatively easy, but their practical importance is low. On the other hand, parasitic alternating (AC) currents are virtually omnipresent in wire-based systems. Such situations exist due to AC ground loops and electromagnetic interference (EMI). However, utilizing AC currents for attacks is a harder problem. Here, we introduce and demonstrate AC current attacks in various frequency ranges. The attacks exploit a parasitic/periodic AC voltage-source at either Alice’s or Bob’s end. In the low-frequency case, the procedure is the generalized form of the former DC ground-loop-based attack. In the high-frequency case, the power density spectrum of the wire voltage is utilized. The attack is demonstrated in both the low and the high-frequency situations. Defense protocols against the attack are also discussed.


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