Search results for "Converter"
showing 10 items of 275 documents
Proton exchanged waveguides in LiNbO<inline-formula><sub>3</sub></inline-formula> and LiTaO<inline-formula><sub>3…
1998
Transconductance Converters Based on Current Mirrors Applied to pH Measurement Using ISFET Sensors
2009
New transconductance circuits (V/I converters) are designed based on current mirrors and operational amplifiers. Their input/output characteristics and the influence of DC parameters are obtained. Experimental results were performed, comparing them with the simulated results. An electronic instrumentation circuit is designed based on one of the transconductance converters analyzed. The purpose of this circuit was to condition the response of an ion-sensitive field-effect transistor (ISFET) to measure pH. In the proposed application, the V/I converter presented provides the stability and accuracy of the ISFET operating point, making an easy characterization procedure and the design of multic…
Predictive dead time controller for GaN-based boost converters
2017
A dynamic dead time controller is presented, specifically intended to operate in synchronous boost converters based on GaN field-effect transistor switches. These transistors have a reduced stored charge with respect to silicon metal–oxide–semiconductor field-effect transistors with similar breakdown voltage and series resistance, and can operate at higher frequencies with reduced switching losses. On the other hand, the voltage drop in reverse conduction is typically more than doubled with respect to silicon devices resulting in relevant power losses during the free-wheeling phases. Therefore, dynamic control of dead time can be profitably applied even in converters operating in the tens o…
Detection of Partial Discharges at Square Shaped Voltages
2018
Due to the wide use of electronic converters and the introduction of new powerful power electronics devices, the input waveforms most often used are becoming much different than the traditional power frequent sinusoidal one. In High Voltage (HV) apparatus particularly, this condition can increase the stress on the insulation systems that may lower the reliability of the whole power grid. This type of input voltage, often showing an increased voltage gradient, causes problems in the Partial Discharge (PD) measurement setup and acquisition systems, also due to the increased harmonic content. In this paper, the main aim is to discuss how to suitably approach the measurement technique of PDs at…
Maximum Power Point Tracker for Standalone PV System Using Neural Networks
2019
In this work, designing and implementation of a maximum power point tracker (MPPT) based on an artificial neural network is proposed. The output voltage of the selected photovoltaic array is controlled by a DC to DC boost converter in a way that the PV array generates the available possible maximum power correspond to the available solar irradiance and temperature. The neural network (NN) is capable of forecasting the required terminal voltage of the PV array in order to generate the possible maximum power. The pulse width modulation (PWM) signal, which drives the boost converter, is generated through a raspberry pi according to the forecasted terminal voltage. The terminal voltage of the P…
Novel Isolated Multiple-Input Buck-Boost DC-DC Converter for Renewable Energy Sources
2021
An isolated multiple input dc-dc converter (MIC) with unidirectional buck-boost characteristics and simultaneous power transfer is proposed for multi-sources in renewable energy systems in this paper. When compared to existing isolated MICs, the proposed MIC significantly reduces the component count and control complexity since it requires a fixed coupled inductor with only one primary and secondary winding each for any number of inputs and does not require any phase-shifted pulse-width modulation. The operation of the proposed converter for simultaneous power transfer from multiple sources with varying voltages is numerically verified in simulation and validated on OPAL-RT’s OP5700 hardwar…
Active snubber network design and implementation on the primary side of an isolated &#x0106;uk converter realizing soft-switching for efficiency …
2008
This paper describes the process of improving the efficiency of an existing isolated DC/DC converter based on CUK topology with secondary side synchronous rectification, by means of the introduction of an active snubber network on the primary side. The snubber circuit reduces to zero the switching losses during the off-time interval of secondary SR. In particular, the efficiency improvement is due to the elimination of the primary MOSFET Coss output capacitance losses, and mainly of the reverse recovery losses on the secondary SR MOSFET. However, the insertion of the active snubber creates itself additional losses in the circuit, and therefore to measure the really introduced benefit it is …
NON-LINEAR INDUCTOR CONTRIBUTION TO HARMONIC SPECTRUM IN POWER CONVERTERS
The paper investigates the harmonic content in DC/DC power converters where the inductor is operated in the non-linear region. This operation is often exploited to use lighter and cheaper inductors; as a drawback, an increasing number of harmonics is noticeable. A theoretical analysis is proposed. It is based on a polynomial model of the inductor used in a boost converter. Results are given by the spectra of the output voltage performed on a circuit prototype.
H<inf>&#x221E;</inf> control of markovian switching systems with time-delays: Applied to DC-DC converters
2011
The DC-DC switching power converters are highly nonlinear systems. Consequently, the conventional linear controls based on averaging and linearization techniques will result in poor dynamic performance or system instability. In order to resolve this problem, in this paper a robust state feedback H∞ control is proposed for these systems under Markovian switching with mixed discrete, neutral and distributed delays. Based on the Lyapunov-Krasovskii functional theory, some required sufficient conditions are established in terms of delay-dependent linear matrix inequalities for the stochastic stability and stabilization of the considered system using some free matrices. The desired control is de…
The experience of building and operating COMPASS RICH-1
2010
COMPASS RICH-1 is a large size gaseous Imaging Cherenkov Detector providing hadron identification in the range from 3 to 55 GeV/c, in the wide acceptance spectrometer of the COMPASS Experiment at CERN SPS. It uses a 3 m long C(4)F(10) radiator, a 21 m(2) large VUV mirror surface and two kinds of photon detectors: MAPMTs and MWPCs with CsI photocathodes, covering a total of 5.5 m(2). It is in operation since 2002 and its performance has increased in time thanks to progressive optimization and mostly to a major upgrade which was implemented in 2006. The main characteristics of COMPASS RICH-1 components are described and some specific aspects related to the radiator gas system, the mirror alig…