The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
A adaptive sliding mode observer was proposed for the speed identification of a sensor-less vector control system of doubly fed wind turbine. This strategy combines adaptive control with variable structure control, and selects the rotor currents as model outputs, and formulates a slide mode surface according current error to get speed observer expression. By using small signal model, the convergence...
The authors propose a scheme of simulation training system based on SOA for switching operation. This system is developed by Microsoft Visual Studio 2010, and realizes the basic functions such as Switching Operation, Monitoring panel display. The system provides students with the online training platform to help them as soon as possible into the work role as a qualified professional and technical...
At present, the temperature monitoring of contact terminal is not integrated into the available intelligent manipulation device for high-voltage switchboard. To develop a high-voltage switchgear comprehensive system of on-line monitoring and fault diagnosis which can measure the contactor temperature rise is very important to guarantee the normal operation of the high-voltage switchgear. Design on...
The ship anti-rolling tank test platform is a specific-designed synthesis system used to imitate the ship's movement in the sea waves. An electro-hydraulic servo system featuring high accuracy and fast response is employed. This latter has highly nonlinear phenomena such as fluid compressibility, the flow-pressure relationship and dead band due to the internal leakage and hysteresis. Usually, conventional...
Due to the small fault current and unstable arc, the fault location problem of low power coal mine phase-to-ground fault has not got thoroughly solved. The existed leakage judging method of coal mine low voltage distribution network has the disadvantages of large error and long action time, so it is unfavorable for safety operation. This paper give a new methods which based on the model parameter...
In order to increase the work efficiency of oil pumping system, the key problems in the operation process of oil pumping system are summarized. The experiment system for oil pumping is established, the mathematic models of oil pumping system are analyzed, objective function, boundary condition and calculated method in oil extraction system are discussed, the optimum control strategy in the operation...
The pulse width modulation technique and dynamic operating mode characteristics of direct drive permanent magnet synchronous generator (PMSG) are researched firstly. A novel sliding mode variable structure directed power control algorithm applied to PMSG is proposed, and then design the controller using tip speed radio and flux-weakening control scheme. It can not only provide a constant switching...
Three-level inverters are increasingly being used in high power middle voltage applications due to their superior performance compared to two-level inverters. However, The neutral point fluctuation problem associated with the traditional three-level inverter like neutral-point clamped inverter is difficult to deal with. This paper proposes a novel three-level topology which is constructed by two three-phase...
A very important and useful class of digital circuits, counters, useful in many applications of digital systems have been discussed in detail, such as the methods and techniques for using of 4-bit synchronous binary counter 74LS161 to constitutes Mod-M counter and to make of frequency divider. Standard counter Ics are available for counting in normal binary sequence for different modules. In many...
For the problem of harmonic detection delay by the instantaneous reactive power method, a TS fuzzy logic along with synthetic sinusoid generation technique based shunt active power filter is proposed. The desired reference current are extracted using this algorithm and this method maintains the dc-side capacitor voltage of the inverter nearly constant. The VSI gate switching signals are derived from...
The rapid development of the grid and communication technology for raising the level of power management automation provides a strong condition. Traditional data replication system in rural power network has not keep up with the pace of modernization, the change the traditional and inefficient data replication system has become the goal of power enterprises. Aiming at the deficiency of FC-SAN technology...
Aimed at building a new scheduling system by using internet, public switched telephone network and globle system for mobile communications. The user books schedule in website. The system reminds the user by phone or short message in exact time. The system is introduced in detail, including the steps to realize such as web site, accurate for timing, short message and ip call. It has be applied by any...
The isolated-type symmetrical half-bridge bidirectional DC/DC converter has simple structure and can easily achieve zero voltage switching, but the criterion of designing the resonant devices to implement Zero voltage switching is obviously lacking. Based on the analysis of the circuit topology and operating principle, the equivalent circuit of soft-switching is presented, and the mathematical expressions...
Based on the vector control system of permanent magnet synchronous motor (PMSM), an integral Variable Structure Control (VSC) is designed in this paper through the application of variable structure control theory with sliding-mode. Furthermore, by means of Matlab / Simulink, a simulation analysis on the control structure is performed to examine the effects of different parameters on the system performance...
In order to make more profound comprehension of propagation characteristics for E-M signals from partial discharge in GIS, the GIS models with isolating switch are creation to analysis the E-M wave propagation characteristics using FDTD method. The influences of the isolating switch and difference receive degree on the propagation characteristics of E-M wave with comparison of isolating switch close...
This paper presents a field programmable gate array (FPGA) prototype of a 6-digit digital clock displaying time on a four-digit seven-segment LED module. The design of the digital clock is based on the Very High Speed Integrated Circuit Hardware Description Language (VHDL) hardware description language, synthesized by the Xilinx Synthesis Technology (XST) synthesizer, and implemented per Spatan-3...
Considering the disadvantages of torque ripple and current distortion on traditional direct torque control (DTC) of induction motor, a new direct torque control strategy based on predicting the stator voltage vector is presented in this paper. The stator voltage prediction control scheme estimates the desirable stator voltage of the next cycle by the current state value and the desirable flux and...
Under certain conditions, semiconductor diodes will produce the phenomenon of current periodic change in DC circuit. We designed a experiment due to some certain silicon epitaxial planar diode, and the test results showed that when the current flowing the diode overruns rated value, current regular relaxation oscillation appears, and the oscillation period is in several seconds. As long as the voltage...
Matrix Converter (MC) will be widely used for the ship electric propulsion drives system with the development of the power electronic technology. A new matrix converter topology has been designed for the dual-three-phase PMSM in this paper. This topology has six phase input and overcomes the standard matrix converter disadvantage. Some control methodologies have also been researched on. By simulation...
The study of minimizing torque ripple is one of the most popular projects in SRM research area. We introduced the existing 8/6 SRM about basic parameters and torque characteristics and optimized pole arcs by using two-dimensional finite element method(FEM) for the purpose of reducing torque ripple and improving performance. This paper introduce the modeling of switched reluctance motor using Maxwell...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.