Search results for "rectifier"
showing 10 items of 24 documents
Optimal matching between optical rectennas and harvester circuits
2017
This paper deals with optimal coupling issues between rectennas and harvesting circuits. An optical rectenna consists of a nanoantenna usually coupled with an ultra-high speed rectifier. These devices aim to receive and convert solar and thermal radiation in a DC voltage, while a harvester circuit provides the energy to be stored. The rectenna impedance is influenced both by its structure and by the rectifying diode, the harvester circuit impedance has to be matched to optimize the power transfer. The purpose of this contribution is to discuss the best impedance conditions by taking into account the constraints that are due to the individual devices the conversion system consist of. Finally…
A PC-based low cost impedance and gain-phase analyzer
2008
Abstract In this paper, we present a practical and inexpensive impedance/gain-phase analyzer (IGPA), which is very useful in the design of electronic circuits. This instrument allows the Bode diagram of any network or electronic circuit with an input and an output to be obtained, even though this implementation was not previously known. It can also obtain the module and phase diagrams of any impedance separately. The device under test (DUT) is connected to a personal computer (PC) via the parallel port by means of an electronic circuit implemented for this purpose. The results are shown on the screen of the PC and can be accessible for use in any further operation. The instrument operates i…
Design of a LLC Resonant Converter for Powering a PEM Electrolyzer
2021
International audience; This paper proposes the design of a LLC resonant converter to supply a proton exchange membrane (PEM) electrolyzer. The PEM requires a low voltage with high current, a reduced output voltage ripple, and an overdamped dynamic behavior of the converter to avoid voltage overshoots. The designed converter allows satisfying the design constraints, minimizing switching and reverse recovery losses; the efficiency is influenced mainly by the output rectifier's conduction losses.
Isolated two-stage passive PFC rectifier for the Radioisotope Stirling Generator
2013
This paper describes an isolated, passive power factor correction rectifier devised for low-voltage, large-inductance, single-phase alternator, like the one used in the Radioisotope Stirling Generator. The power converter splits into two independent stages, the front-end rectifier corrects the power factor by adding a series capacitor in the AC line. Further, the rectifier, thanks to the alternator inductance, behaves as a constant-current source that powers a current-fed, zero voltage and zero current switching push-pull stage. This approach takes advantage of all parasitic elements to increase power density while keeping simple and reliable. Full description and analysis is given as well …
Biomolecular conjugation inside synthetic polymer nanopores via glycoprotein-lectin interactions
2011
We demonstrate the supramolecular bioconjugation of concanavalin A (Con A) protein with glycoenzyme horseradish peroxidase (HRP) inside single nanopores, fabricated in heavy ion tracked polymer membranes. Firstly, the HRP-enzyme was covalently immobilized on the inner wall of the pores using carbodiimide coupling chemistry. The immobilized HRP-enzyme molecules bear sugar (mannose) groups available for the binding of Con A protein. Secondly, the bioconjugation of Con A on the pore wall was achieved through its biospecific interactions with the mannose residues of the HRP enzyme. The immobilization of biomolecules inside the nanopore leads to the reduction of the available area for ionic tran…
Partial discharges behavior under different rectified waveforms
2017
In this work, a previous software used to simulate partial discharges (PDs) under Alternating Current (AC) stress has been modified in order to evaluate the PDs behavior under a voltage stress close to the Direct Current (DC) waveform. By using a full-wave and a half-wave rectifier, the specimen with an air void defects has been subjected to a gradual constant stress. Finally, a capacitive filter has been inserted in order to produce a steadier voltage supply. Simulation results show that under an almost DC waveform, the PDs activity become less compared to AC stress.
Voltage stability of Small Hydro Generator Based DC Microgrid
2019
Hydro energy is the vigorous form of renewable energy sources (RES) to generate electricity. It is considered to be an efficient source among the RES due to its abundant potential. Based on the scale at which the power has been generated, operating head, hydro generators are classified into large, small, micro, pico generators. In this paper, a hand in hand approach of inner and outer control loop strategy is proposed to accomplish the voltage stability of a small hydro generator based DC microgrid (MG). The DC MG considered in this paper is operating under the unusual condition where solar, wind and main grid are off due to irregularity. Moreover, the load is of varying nature. Outer contr…
Control of ultra-high switching frequency power converters using virtual flux-based direct power control
2017
This paper presents a control technique for ultra-high switching frequency rectifiers known as virtual flux-based direct power control (VF-DPC). This method utilizes AC voltage sensors to provide better power quality at the input and output of power converters. Performance of an ultra-high switching frequency converter using the extended and conventional VF-DPC method is analyzed. The analysis has shown that the extended VF-DPC method can reduce better the total harmonic distortion (THD) of input currents and the ripples of the output DC voltage as compared to conventional VF-DPC. Finally, the effect of switching frequency and inductance size on rectifier operation is investigated in this s…
Novel zero-current-transition circuit for three-phase buck rectifiers
2002
ZCT circuits have already been proposed in the past and are becoming more and more popular in high power rectifiers and inverters where bipolar devices have to be used (IGBTs or even BJTs). Although ZCT techniques have already been applied to three-phase boost type topologies, no ZCT circuits have been proposed for three-phase buck-type topologies. The authors propose a new load independent ZCT circuit for a three-phase buck-type rectifier which achieves high noise reduction, voltage stress reduction and zero current transitions to almost all transitions of the rectifier's switches including the additional auxiliary switches.
Simple equipment to measure biomechanical quantities of muscles and organs which includes a polarity-programmable peak detector
1982
Biomechanical measurements of muscles and organs require appropriate measuring equipment. As far as the static properties are concerned, the excursion of the bender bar of stress should be without force. The bender bar of force, however, ideally should not elongate under load. Because natural frequency is the most important boundary condition, the bender bar should be developed with this in mind. The developed bars imposed an insignificant preload to the muscle or to the organ. The small changes in resistance occurring in the resistance strain gauges affixed to the bars require the use of a highly stable amplifier. A new amplifier was accordingly developed based on the principle of an instr…