Search results for "circuit"
showing 10 items of 936 documents
DC link voltage swinging and load current unbalance in fault tolerant VSI. overview and compensation strategies
2015
The topic of this paper is the discussion on the performance of a three-phase fault tolerant inverter with particular attention to the underrated aspect of current unbalances occurring due to the DC link voltage fluctuates after the inverter reconfiguration. Capacitor voltage unbalance affects not only the average output voltage of the inverter, but also its performance. In fact, the inverter performance depends on the fluctuating DC-link voltage components rather than on the average DC-link voltage. After a brief analysis of the voltage fluctuation phenomena resulting from fault tolerant configuration and their effect on load current unbalance, the Authors consider different compensating p…
Reconfigurable digital instrumentation based on FPGA
2004
A novel application of FPGA to realize digital test equipment is proposed. It takes advantage of the dynamic reconfigurability of FPGAs so easily tailoring custom test functions in the same instrument. This results in high effective, compact and low cost instruments.
An Investigation of Protection Devices Coordination Effects on Distributed Generators Capacity in Radial Distribution Systems
2013
In the recent years, with the concept of Smart Grid, there are a great interest in integration of renewable energy based distributed generation (DG) units at distribution level. Along with a number of benefits, penetration of DG units in the distribution system imposes some serious challenges; protection requirements turns up as one of the most critical challenge in DG integration. In this paper the possibility and the potentiality of occurring mis-coordination between protection devices in radial distribution network is studied. The impacts of protection devices coordination on DG capacity are investigated. The penetration level, number, and location of interconnected DGs are used as param…
Magnetic Tunnel Junction (MTJ) Sensors for Integrated Circuits (IC) Electric Current Measurement
2013
We report on MgO Magnetic Tunnel Junction (MTJ) devices focusing on their potential application in the measurement of electrical current at the integrated circuit level. Single devices and full bridges have been specifically developed for this purpose. A sort of different designs regarding their geometry arrangement as well as the number of constitutive elements have been tested. Experimental characterization has been performed and results including impedance and sensitivity measurements are given.
A new backward/forward method for solving radial distribution networks with PV nodes
2008
Abstract In this paper, a new backward/forward (b/f) methodology for the analysis of distribution systems with constant power loads is presented. In the proposed method, at each iteration, the loads are considered as constant impedances; in the backward sweep all the network variables (bus voltages and branch currents) are evaluated considering a scaling factor which is determined at the end of the backward phase. Indeed the forward sweep is eliminated and the node voltages calculation does not demand the sequentiality needed in the b/f methodology. The developed method, although deriving conceptually from the b/f methodology, presents only the backward phase in which all the network variab…
Quasifractal planar microstrip resonators for microwave circuits
1999
We propose a new shape for microwave planar circuits using the self-similarity of the fractal geometry. This new shape allows the generation of numerous resonant frequencies for this microwave planar resonator due to the surface's encasing. The resonant frequency assessment can be useful for the concept of filters or wide frequency band matching loads as examples, without consuming circuit surface. ©1999 John Wiley & Sons, Inc. Microwave Opt Technol Lett 21: 433–436, 1999.
A DC behavioral electrical model for quasi-linear spin-valve devices including thermal effects for circuit simulation
2011
An advanced model for quasi-linear spin-valve (SV) structures is presented for circuit simulation purposes. The model takes into account electrical and thermal effects in a coupled way in order to allow a coherent representation of the sensor physics for design purposes of electronics applications based on these sensor devices. The model was implemented in Verilog-A and used in a commercial circuit simulator. For testing the model, different SV structures have been specifically fabricated and measured. The characterization included DC measurements as well as steady-state and transient thermal analysis. From the experimental data, the parameters of the model have been extracted. The model re…
Effects of electrical and mechanical parameters on the transient voltage stability of a fixed speed wind turbine
2011
Abstract In this paper the dynamic behaviour of a wind turbine connected to the grid is examined. The model of the fixed speed wind turbine has been developed with the Simulink simulation tool (Matlab Inc.) It is composed of the induction generator, the shaft system, an aerodynamic model of the wind turbine rotor and the pitch control system. Using this model, a three-phase fault is applied close to the wind turbine and cleared by disconnecting the faulty line. The rigorous implementation of the simulink model allowed the authors to evaluate the exact dependence of various electrical parameters for the induction generator on voltage stability. Furthermore, the effects of wind turbine mechan…
Phase Margin Degradation of a Peak Current Controlled Converter at Reduced Duty Cycle
2010
An inner current loop is frequently used in many switching power supplies to achieve higher stability and a good current sharing. Nevertheless, some problems derived from its practical implementation can be encountered. One problem is related to the need of filtering of the sensed current and was discovered by the authors in the implementation of a 500 W converter, when peak current control was applied by sensing the switch current. This paper will demonstrate mathematically that an RC filter not only filters out the noise but also can cause a degradation of the phase margin, especially, if the needed duty cycle is close to zero. The main reason for it is the severe distortion of the curren…
Can Atmospheric Neutrons Induce Soft Errors in NAND Floating Gate Memories?
2009
Atmospheric neutrons can interact with the matter inside a microelectronic chip and generate ionizing particles, which in turn can change the state of one or more memory bits [soft error (SE)]. In this letter, we show that SEs are possible in Flash memories, although with extremely low probabilities. While this problem will increase for future technologies, we do not expect SEs to be the reliability limiting factor for further floating gate scaling.