Papers by Keyword: Inductance

Abstract: Electric currents of the order 100 kA flow in secondary current leads of powerful electrotechnological installations. It causes active power losses and electromagnetic field power dissipation. To improve engineering-and-economical performance it is necessary to minimize pure resistance and inductance of current lead and symmetrize the parameters over phases while designing the installation. The paper considers approaches to formulate modern method for calculation pure resistance and inductance of secondary current leads in powerful electrotechnological installations.Interleaved conductors' packages have been examined as the longest partition of secondary current leads in ore-thermal furnace. The examination was carried out with numerical simulation of electromagnetic field of groups of interleaved water-cooled tubular buses (bus-packages) in ANSYS software. Dependencies of bus-packages pure resistance and inductance and their geometric parameters and interleaving ways for magnetic flux compensation have been obtained. Analysis of obtained results allows defining empiric formulae for calculation of electrical parameters of interleaved packages in powerful electrotechnological installations.

Abstract: In the present paper, we study electromagnetic properties of single-turn, double-turn and DNA-like helices in microwave range. In particular, we determine the magnetic flux density in the center of the inclusions and their inductance and capacitance. In this paper we have numerically obtained the magnetic field of different kinds of helices: the single-turn helical element, the double-turn helical element, the half-turn helical element and DNA-like helical element. For these helical elements the inductance, capacitance and Q factor were calculated numerically.

Abstract: It is clear that lightning strokes produce overvoltages on Transmission Lines (TLs), which can be higher that the Basic Insulator Level (BIL), generating a fault or short circuit. Thus, in order to adequately analyze when a lightning hits on a TL, it is necessary to simulate different elements corresponding to Electric Power Systems (EPSs) as real as possible. In this context, transmission towers are considered crucial parameters in lightning studies, which must be correctly selected and simulated in order to consider reflected voltage waveforms from cross arms. Based on the above said, this paper presents a comparative study corresponding to the transmission tower simulation using two models. The first uses inductances, and the second uses distributed parameters impedances characterized by their impedance and travel time. This paper presents voltage variations that exist in each phase, using different lightning features. Alternative Transients Program (ATP) is used to simulate the TL model considering different lightning currents and the two tower models. Results show that the impedance model analyze reflected waveforms, while that the inductance model does not analyze this issue.

Abstract: Printed antennas fabricated using conductive ink printed on flexible substrate is low-cost and environmental friendly. The inductance and the quality factor are two important parameters for designing RFID antenna and were studied for the printed RFID antennas. The results show that the inductance is not only determined by the size of the designed RFID antenna but also related to the resistance of the printed antenna coils. The inductance increases with the increasing testing frequency, while the Q value decreases with the increasing testing frequency. The soft magnetic ink prepared with γ-Fe₂O₃ was used to enhance the inductance of the printed antennas with printing technology. The inductance of the printed antenna with the magnetic core layer is increased by 5.7% at 13.56 MHz.

Abstract: This paper proposed the Weighted Least Square method (WLS method) to identify the output filter of three-phase PWM converter, which incorporates the signal processing as well as mathematical techniques into conventional Least Square method. It sets different weights to different measurements according to the phase where it locates, based on the discovery of the correlation between accuracy and phase of current. The algorithm is tested in both simulation and experimental environment, and the results validate that proposed method gives accurate estimation in steady state, and can response within 10ms in when grid voltage drops. This method can work under both balanced and unbalanced operating conditions, therefore provides a powerful tool for various control strategies to better understand the operating conditions. Compared with the invasive method, which intentionally inject a series of white noise in the system, proposed WLS method does not bring any turbulence, while compared with conventional Least Square method, it possesses better stability as well as higher accuracy.

Abstract: The inductance and the capacitance on DC side are two important parameter of SVG. In this paper, the effect of inductance and capacitance on DC sides’ voltage control method of SVG is addressed.

Abstract: While designing an ore-thermal furnace it is necessary to minimize and balance its secondary current contact jaw electrical parameters. The study deals with the method of calculating pure resistance and inductance of ore-thermal furnace electrode holder tubes. It is significant because the tubes have complicated wires configuration and their resistance is noticeable in current contact jaw total impedance because of the same half-phase currents flow in tube bundles and absence of magnetic flux compensation. Real bent wires are suggested to be approximated by broken lines. After that both existing and proposed by the authors formulas can be used for calculating inductance and mutual inductance of two straight-line wires arbitrary placed in space. Current distribution non-uniformity along separate tubes is taken into account in an iterative algorithm. Currents in wires are assumed to be equal at the first iteration. Then they are corrected at following steps of the iteration algorithm with respect to wires resistances calculation results. Skin effect and closure effect between wires segments are taken into account when pure resistance is calculated. The proposed method has been applied in the development of the software for calculating ore-thermal furnace secondary current-contact jaw electrical parameters. The method has been approbated in the design of the 60 MVA ore-thermal furnace made by ZAO “Electroterm”, Novosibirsk, Russia. The results obtained have been tested with numeric 3D models created in ANSYS environment. Inductance calculation error is 10%, pure resistance error is 25%.

Abstract: J2EE is set for the distributed computing realization of API, services and protocols developed by SUN. The design objective of J2EE computer development tool is to provide a simple, easy operation development platform for developers, which can reduce the cost of development, shorten the development cycle, and improve the comprehensive performance of computer system. In this paper, we use JSP calculation vessel function module of J2EE to improve the computer economic detection system, and establish data connection between system and the HTML Webpage, which realizes the real-time and continuous detection of the economy. Finally, based on the external demand and exports of industrial products in an area, we detect trade transactions in the region, and do mathematical statistics using the J2EE system, and finally get the trade scale. It provides a new computer method for the research of export trade and economic detection.

Abstract: This paper proposes a novel high power factor LED driver based on SY5800A for interior-lighting applications. High power factor is achieved by using the transformer with back winding coil and the transformer with “sandwich” winding coil. In addition, the proposed driver features cost-effectiveness, high circuit efficiency, low input current ripples and a reduced components count. A sample driver is developed to supply a 15W LED interior-lighting module with a 0.99 power factor. Experimental results demonstrate the functionalities of the proposed circuit.

Abstract: In view of it is often needed to measure the value of the inductance capacitance and signal frequency in the welding and the debugging process of the electronic circuit, specialized equipment due to the huge volume of expensive equipment which is difficult to measure, we use SCM to design a portable measuring instrument which have low cost and can measure the value of inductance and capacitance, as well as signal frequency. It can meet the demand of precision after testing, so as to reach requirements for measuring instrument.