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In this work, undoped and co-doped ZnO:Al:Mn semiconductor thin films and p-type Si diodes were produced via sol-gel technique method. The morphological and optical properties of the produced thin films were investigated using SEM, XRD and UV-Spectrophotometer, respectively. It was observed that the crystal structure of the semiconductor samples had a hexagonal wurtzite structure and the forbidden energy gaps of the samples decreased with increasing Mn contribution. The experimental zero-feed current barrier height (?b(I-V)), rectification ratio, ideality factor and Ion/Ioff parameters of the diodes were determined via the thermionic emission model. It was determined that the produced Al/p-Si/ZnO:Al:Mn/Al diode had high rectification ratio and Ion/Ioff values of 1.56x105 and 1.54x104, respectively, and exhibited light-sensitive behaviour. Also, the capacitance barrier height (?b(C-V)), built-in voltage (Vbi), diffusion potential (Vd), donor concentration (Nd) and depletion layer width (Wd) values of Al/p-Si/ZnO:Al:Mn/Al diode were calculated via the C-2-V graph drawn under 1MHz frequency. The results show that the fabricated diodes can be used as photodiodes or photosensors in optoelectronic applications. © 2023 Gazi Universitesi Muhendislik-Mimarlik. All rights reserved. Firat Üniversitesi, FU: FF16.24 This study was supported by Firat University, for PhD thesis (Project No. FF16.24).

This paper shows a new concept to generate medium voltage (MV) in wind power application to avoid an additional transformer. Therefore, the generator must be redesigned with additional constraints and a new topology for the power rectifier system by using multiple low voltage (LV) power rectifiers connected in series and parallel to increase the DC output voltage. The combination of parallel and series connection of rectifiers is further introduced as DC-cascade. With the resulting DC-cascade, medium output voltage is achieved with low voltage rectifiers and without a bulky transformer. This approach to form a DC-cascade reduces the effort required to achieve medium DC voltage with a simple rectifier system. In this context, a suitable DC-cascade control was presented and verified with a laboratory test setup. A gearless synchronous generator, which is highly segmented so that each segment can be connected to its own power rectifier, is investigated. Due to the mixed AC and DC voltage given by the DC-cascade structure, it becomes more demanding to the design of the generator insulation, which influences the copper fill factor and the design of the cooling system. A design strategy for the overall generator design is carried out considering the new boundary conditions. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.

In this work, the secondary side controlled wireless power transfer (WPT) converter using a LC/S compensation topology is proposed. The constant voltage charging control mode of the proposed converter is evaluated based on high efficiency. In the secondary side, a semi-bridgeless active rectifier (SBAR) is used for the output voltage regulation. In order to improve the efficiency performance of the converter, the pulse density modulation (PDM) control method is applied to the switches of the SBAR. The primary switches operate at the constant operation frequency as independent of the secondary side. There is no communication needed between primary and secondary sides of the proposed converter. Besides, the switches of the SBAR operate with soft switching. The basic principles of the LC/S compensation network and SBAR topology are presented with steady state analysis. The PDM control strategy applied to the switches of the SBAR is discussed. In order to validate the performance of the proposed converter, a prototype is built with 8 cm air gap coreless coupling coils. The input voltage of the converter is 30 V, and its maximum output power is 60 W. The maximum efficiency is achieved as 85.26% at full load condition during CV regulation. © 2021 Informa UK Limited, trading as Taylor & Francis Group.

Spin-diodes are usually resonant in nature (GHz frequency) and tuneable by magnetic field and bias current with performances, in terms of sensitivity and minimum detectable power, overcoming the semiconductor counterpart, i.e. Schottky diodes. Recently, spin diodes characterized by a low frequency detection (MHz frequency) have been proposed. Here, we show a strategy to design low frequency detectors based on magnetic tunnel junctions having the interfacial perpendicular anisotropy of the same order of the demagnetizing field out-of-plane component. Micromagnetic calculations show that to reach this detection regime a threshold input power has to be overcome and the phase shift between the oscillation magnetoresistive signal and the input radiofrequency current plays the key role in determining the value of the rectification voltage.

This paper deals with an energy management issue for the grid-connected renewable energy sources connected with unbalanced loads. In the gridconnected energy systems, conventional energy management methods are used to manage balanced active power supplied from energy units to grids/ loads. However, unbalanced load groups, like single-phase loads, parallel rectifiers, and three-winding transformers tied to the electric networks, cause zero-sequence currents and impair the power stability at the gridside. For this purpose, in this study, an improved power flow controller method with zero-sequence current injection is proposed in order to compensate zero-sequence currents and ensure phase equilibrium at grid-side. Therefore, it is tested in a photovoltaic/fuel cell-based hybrid energy system with unbalanced loads, including zero-sequence. Instead of the conventional abc/dq frame used in energy management control, the proposed method makes use of triple αβ transforms and implemented in each phase to be controlled separately under designed unbalanced load groups. Hence, it abolishes the weakness of the conventional abc/dq frame method that generates the undesirable mean reference for zero-sequence situations. In addition, the designed system cannot only mitigate the grid-side zerosequence currents but also supply active powers to three-phase loads/ grids. The optimization of energy systems is also provided through a maximum power point tracking algorithm. In the performance testing, the energy generation units are performed under three states, which produce different supplied currents at the output. In the performance section, it is obvious that zero-sequence components at grid-side currents are significantly reduced via the proposed power flow controller-based system. Also, the results are compared to the conventional method in order to verify the validity of the proposed approach under the designed load groups.

The hybrid integration of small-scale wind and solar energy conversion systems can be used for on- and off-grid applications. This paper investigates a stand-alone off-grid application of a hybrid small-scale wind turbine and photovoltaic (PV) cell microgrid to supply houses in rural Iraq far from the utility grid. Experimental investigations were performed to measure wind speed and solar radiation, as well as the DC voltage in the rectifier section of a small-scale permanent magnet synchronous generator (PMSG) wind turbine and the DC voltage in a PV cell for 24 hours. The results showed that using a small-scale hybrid wind and solar generating system for off-grid applications in Iraq is possible if the components are equipped with proper charge controllers that perform maximum power point tracking (MPPT) during wind speed and solar radiation fluctuations.

Here we present the fabrication of LEDs based on porous GaN produced by chemical vapor deposition (CVD) and reviewed the work done that allowed demonstrating p-n junction rectifiers and MOS diodes in a simple manner and without involving post-growth steps to induce porosity. p-n junction rectifiers exhibited stable rectification in the range ±1–±5 V, with very stable values of current with time. MOS diodes were fabricated in a single growth step formed by a MgO dielectric interlayer in between Mg-doped porous GaN and a Mg-Ga metallic alloy. Despite the high resistivity observed in the LEDs fabricated, that induced a turn on voltage of ∼13 V, the emission consisted only in one peak centered at 542 nm. Our porous GaN films exhibit random porosity when compared to arrays of nanostructures, however, their easy deposition over large areas without dominating leakage currents is promising for wideband gap applications.

A Wireless Power Transfer Network (WPTN) aims to support devices with cable-less energy on-demand. Unfortunately, wireless power transfer itself-especially through radio frequency radiation rectification-is fairly inefficient due to decaying power with distance, antenna polarization, etc. Consequently, idle charging needs to be minimized to reduce already large costs of providing energy to the receivers and at the same time reduce the carbon footprint of WPTNs. In turn, energy saving in a WPTN can be boosted by simply switching off the energy transmitter when the received energy is too weak for rectification. Therefore in this paper we propose, and experimentally evaluate, two "green" protocols for the control plane of static charger/mobile receiver WPTN aimed at optimizing the charger workflow to make WPTN green. Those protocols are: 'beaconing', where receivers advertise their presence to WPTN, and 'probing' exploiting the receiver feedback from WTPN on the level of received energy. We demonstrate that both protocols reduce the unnecessary WTPN uptime, however trading it for the reduced energy provision, compared to the base case of 'WPTN charger always on'. For example, our system (in our experiments) saves at most approx. 80% of energy and increases 5.5 times the efficiency with only approx. 17% less energy possibly harvested., Comment: submitted for possible publication. http://www.es.ewi.tudelft.nl/reports/ES-2015-01.pdf

Minayi, Elham (Dogus Author) -- Conference full title: 25th IEEE International Conference on Electronics Circuits and Systems, ICECS 2018; Bordeaux; France; 9 December 2018 through 12 December 2018. Using the recently developed Add-Differentiate 5-terminal Integrated Circuit, AD-IC (which possess 12 CMOS transistors only), augmented with two diodes, a new rectifier configuration is presented. Transistor level circuit and its layout are provided and the rectifier is simulated with parameters extracted from the layout showing very good conformity with desired rectifier behavior. Finally, a table of comparison of the proposed rectifier with fourteen others, existing in the literature, is included to conclude the paper.

Aydin, Hasan/0000-0003-1622-2436; Celebi, Cem/0000-0003-1070-1129; Varlikli, Canan/0000-0002-1081-0803, WOS: 000425322400002, PubMed: 29447121, We have investigated the effect of a poly (3-hexylthiophene-2.5-diyl)(P3HT)-graphene bilayer electrode on the photoresponsivity characteristics of Si-based Schottky photodetectors. P3HT, which is known to be an electron donor and absorb light in the visible spectrum, was placed on CVD grown graphene by dip-coating method. The results of the UV-vis and Raman spectroscopy measurements have been evaluated to confirm the optical and electronic modification of graphene by the P3HT thin film. Current-voltage measurements of graphene/Si and P3HT-graphene/Si revealed rectification behavior confirming a Schottky junction formation at the graphene/Si interface. Time-resolved photocurrent spectroscopy measurements showed the devices had excellent durability and a fast response speed. We found that the maximum spectral photoresponsivity of the P3HT-graphene/Si photodetector increased more than three orders of magnitude compared to that of the bare graphene/Si photodetector. The observed increment in the photoresponsivity of the P3HT-graphene/Si samples was attributed to the charge transfer doping from P3HT to graphene within the spectral range between near-ultraviolet and near-infrared. Furthermore, the P3HT-graphene electrode was found to improve the specific detectivity and noise equivalent power of graphene/Si photodetectors. The obtained results showed that the P3HT-graphene bilayer electrodes significantly improved the photoresponsivity characteristics of our samples and thus can be used as a functional component in Si-based optoelectronic device applications.

In this paper, a new low-power versatile current-mode rectifier is proposed. As a salient feature, the proposed rectifier provides two positive half-wave, two inverting negative half-wave or two full-wave outputs from the same configuration. The proposed circuit employs only a dual-output second-generation current conveyor (DO-CCII) and a core rectifying circuit consisting of twelve MOS transistors. The input and output signals are current. Favorably, by adding two additional transistors, the proposed rectifier can also rectify voltage signals with electronic tuning capability. The simple and MOS only structure of the proposed circuit is highly attractive from integration point of view. In spite of providing multiple outputs at the same time, the proposed rectifier enjoys low power consumption. PSPICE simulations using 0.18 mu m CMOS parameters and supply voltage of +/- 0.9 V demonstrate a precise operation and good temperature stability. (C) 2017 Elsevier GmbH. All rights reserved.

Minaei, Shahram (Dogus Author) -- Yıldız, Merih (Dogus Author) In this paper, a voltage-mode full-wave rectifier circuit is proposed. The proposed full-wave rectifier circuit consists of only a single negative-type second-generation current conveyor, two diodes, and two matched resistors. The proposed circuit, without requiring any external bias voltages and currents, has a simple structure using a minimum number of active and passive components. It is implemented with AMS 0.35 mu m technology operating with +/- 1.65 V. Computer simulation and experimental results are included to verify the theory. (c) 2017 Sharif University of Technology. All rights reserved.

A novel topology for realizing voltage-mode (VM) full-wave rectifier/sinusoidal frequency doubler based on current feedback operational amplifiers (CFOAs) and n-channel metal-oxide semiconductor (NMOS) transistors is proposed in this study. The proposed full-wave rectifier structure employs two CFOAs and three enhancement-mode NMOS transistors. With a slight modification, the sinusoidal frequency doubler circuit can be adopted from the full-wave rectifier circuit by replacing a grounded resistor instead of one of the NMOS transistors. Both of the proposed circuits enjoy low output and high input impedance properties which make them convenient for cascading easily with other VM circuits without needing any extra buffer circuits. No passive component matching conditions are needed. The proposed circuits are simulated by using SPICE program to verify the theoretical analysis. © 2017, Springer Science+Business Media, LLC.

Pulse Width Modulated AC drives equipped with small DC-link capacitor are becoming an attractive solution for electric drive applications with moderate requirements for shaft dynamic performance. However, when these drives are fed from a weak grid a resonance between the line side impedance and the DC-link capacitor appears. Due to this resonance, the THD and the partially weighted harmonic distortion of the line currents are increased, which may rise compatibility problems with the AC line harmonic standards. By using vector control the motor drive is transformed into a constant power load from the DC-link point of view, leading to instability of the entire drive system. This paper proposes a novel DC-link voltage compensation method, which can reduce the amplitude of the above mentioned oscillation, while the large DC-link voltage variation, caused by the rectification can be eliminated from the motor current. The method has been experimentally validated and the results show excellent performance. Moreover, the proposed compensation method can be applied for any kind of load connected to a three-phase passive rectifier equipped with small capacitor.

In this paper, high-efficiency design methodology of a zero-voltage-switching full-bridge (ZVS-FB) pulse width modulation (PWM) converter for server-computer power supply is discussed based on self-driven synchronous rectifier (SR) performance. The design approach focuses on rectifier conduction loss on the secondary side because of high output current application. Various-number parallel-connected SRs are evaluated to reduce high conduction loss. For this approach, the reliability of gate control signals produced from a self-driver is analyzed in detail to determine whether the converter achieves high efficiency. A laboratory prototype that operates at 80 kHz and rated 1 kW/12 V is built for various-number parallel combination of SRs to verify the proposed theoretical analysis and evaluations. Measurement results show that the best efficiency of the converter is 95.16%. © 2016 KIPE.

In this paper, a new voltage-mode (VM) full-wave rectifier circuit employing two plus-type differential voltage–current conveyors, two grounded resistors, and two diodes is proposed. The proposed full-wave rectifier enjoys high input impedance and low output impedance; accordingly, it is suitable for direct cascading with other VM circuits without requiring additional buffers. It employs only two grounded resistors which are advantageous for integrated circuit implementations. However, it needs a single resistor-matching condition. It is simulated using SPICE program to verify the theoretical analysis. © 2016, Springer Science+Business Media New York.

In recent years, some converter structures and analyzing methods for the voltage regulation of stand-alone self-excited induction generators (SEIGs) have been introduced. However, all of them are concerned with the three-phase voltage control of three-phase SEIGs or the single-phase voltage control of single-phase SEIGs for the operation of these machines under balanced load conditions. In this paper, each phase voltage is controlled separately through separated converters, which consist of a full-bridge diode rectifier and one-IGBT. For this purpose, the principle of the electronic load controllers supported by fuzzy logic is employed in the two-different proposed converter structures. While changing single phase consumer loads that are independent from each other, the output voltages of the generator are controlled independently by three-number of separated electronic load controllers (SELCs) in two different mode operations. The aim is to obtain a rated power from the SEIG via the switching of the dump loads to be the complement of consumer load variations. The transient and steady state behaviors of the whole system are investigated by simulation studies from the point of getting the design parameters, and experiments are carried out for validation of the results. The results illustrate that the proposed SELC system is capable of coping with independent consumer load variations to keep output voltage at a desired value for each phase. It is also available for unbalanced consumer load conditions. In addition, it is concluded that the proposed converter without a filter capacitor has less harmonics on the currents. © 2016 KIPE.

wireless power transfer network (WPTN) aims to support devices with cable-less energy on-demand. Unfortunately, wireless power transfer itself-especially through radio frequency radiation rectification-is fairly inefficient due to decaying power with distance, antenna polarization, etc. Consequently, idle charging needs to be minimized to reduce the already large costs of providing energy to the receivers. In turn, energy saving in a WPTN can be boosted by simply switching off the energy transmitter when the received energy is too weak for rectification. Therefore in this paper we propose, and experimentally evaluate, two ggreenh protocols for the control plane of static charger/mobile receiver WPTN aimed at optimizing the charger workflow to make the WPTN reduce idle time of transmitters. Those protocols are: gbeaconing,h where receivers advertise their presence to the WPTN, and gprobingh exploiting the receiver feedback from the WPTN on the level of received energy.We demonstrate that both protocols reduce the unnecessary WPTN uptime, however trading it for the reduced energy provision, compared to the base case of gWPTN charger always on.h For example, our system (in our experiments) saves at most ≈ 80% of energy at the charger with only ≈ 17% less energy possibly harvested. © 2016 IEEE.

Z-source inverter (ZSI) was recently proposed as a single-stage buck-boost dc-ac power conversion topology. It augments voltage boost capability to the typical voltage buck operation of the conventional voltage source inverter with enhanced reliability. However, its boosting capability could be limited; therefore, it may not suit applications requiring a high-voltage boosting gain. To enhance the boosting capability, this paper proposes a new pulsewidth modulation (PWM) technique to control the generation of the shoot-through intervals in three-phase ZSIs. The proposed modulation technique achieves a reliable high-voltage gain operation without adding any extra hardware to the ZSI structure, which preserves its single-stage buck-boost conversion nature. In this paper, the principle of the proposed modulation technique is analyzed in detail, and the comparison of the ZSI performance under the conventional and the proposed PWM techniques is given. The simulation and experimental results are shown to verify the analysis of the proposed concept. 2013 IEEE. Scopus

In the science and engineering, supporting theoretical knowledge with practical information is crucial. Thus, there are laboratory courses together with theoretical lectures in engineering education. However, laboratory applications can't give expected successful results because of insufficient laboratory environment of educational institutions, excessive number of students etc. Depending on the developments in the computer field, concepts such as computer aided education, computer-assisted learning, computer-aided engineering have gained importance. In the carried out study, remote accessible virtual laboratory consisting of six modules is designed for power electronics courses. Realized software which can run online or offline and includes almost forty circuits (rectifiers, dc-dc converters, ac-ac converters, dc-ac converters, power supplies) belongs to power electronics field. Detailed analysis and applications can be realized with the virtual laboratory which also contains description of subjects, animations, online support, environment for preparing lab reports etc. The software is available in Uludag University, 111 undergraduate students and 17 faculty members tested it separately without requesting their personal information. Obtained results from two questionnaires are evaluated here.

This paper proposes a control method that can balance the input currents of the three-phase three-wire boost rectifier under unbalanced input voltage condition. The control objective is to operate the rectifier in the high-power-factor mode under balanced input voltage condition but to give overriding priority to the current balance function in case of unbalance in the input voltage. The control structure has been divided into two major functional blocks. The inner loop current-mode controller implements resistor emulation to achieve high-power-factor operation on each of the two orthogonal axes of the stationary reference frame. The outer control loop performs magnitude scaling and phase-shifting operations on current of one of the axes to make it balanced with the current on the other axis. The coefficients of scaling and shifting functions are determined by two closed-loop prportional-integral (PI) controllers that impose the conditions of input current balance as PI references. The control algorithm is simple and high performing. It does not require input voltage sensing and transformation of the control variables into a rotating reference frame. The simulation results on a MATLAB-SIMULINK platform validate the proposed control strategy. In implementation Texas Instrument's digital signal processor TMS320F240F is used as the digital controller. The control algorithm for high-power-factor operation is tested on a prototype boost rectifier under nominal and unbalanced input voltage conditions. ? 2005 IEEE.

International audience; This paper investigates the use of feedback linearization to develop a control system for regulating the DC voltage and the reactive power of a VSC terminal. Firstly, a direct-quadrature (dq) state-space model of the VSC terminal is established. By analyzing the zero dynamics of the system, the static feedback linearization can be applied when the VSC terminal operates in inversion mode (power flowing from the DC side to the AC one). However, the system is not feedback linearizable when the VSC works in rectification mode (power flowing from the AC side to the DC one). Then, based on a simplified model, a new dynamic is introduced by an additional control variable which yields a higher order system, allowing the terminal to operate in rectification mode. Numerical simulations are carried out to verify the validity of the proposed control system.

Cataloged from PDF version of article. We present ultraviolet-visible (UV/vis) range photodetectors (PDs) based on thin film ZnO (n)/Si (p) heterojunction diodes. ZnO films are grown by the atomic layer deposition (ALD) technique at growth temperatures of 80, 150, 200 and 250 degrees C. The fabricated ZnO (n)/Si (p) photodetectors (ZnO-Si-PDs) show good electrical rectification characteristics with ON/OFF ratios reaching up to 10(3). Under UV (350 nm wavelength) and visible (475 nm wavelength) light illumination, the ZnO-Si-PDs give photoresponsivity values of 30-37 mA W-1 and 74-80 mA W-1 at 0.5 V reverse bias, respectively. Photoluminescence (PL) spectra of ALD grown ZnO thin films are used to support the results.

This paper presents a novel dedicated PWM technique for use with single-phase (or four wire three-phase) multi-level Cascaded H-Bridge Converters. The proposed modulation strategy aims to minimize the unbalance of the DC-Link voltages, for any amplitude of the voltage reference, amongst the different converter cells in order to obtain high-quality waveforms with a low switching frequency. Moreover the device voltage drops and ON resistance, which in high-power multilevel converter have a significant impact on the quality of the produced voltage, are compensated. The technique is described in detail along with the concept of a modular converter prototype for smart grid applications and an outline of its construction. Verification of the modulation effectiveness is provided with simulation and experimental results for a 3kW seven level Cascaded Converter.

In this paper, a CMOS-based one input-two output current-mode (CM) circuit structure for providing full-wave rectification and half-wave rectifications to clarify the theory is proposed. The suggested configuration has many important advantages such as dissipating very less power, employing reduced number of CMOS transistors, having high output impedance currents and without requiring any additional bias currents and voltages. In order to exhibit performance and effectiveness of the proposed topology, SPICE simulation results are given. © 2012 World Scientific Publishing Company.

Increased electrical loading on aircraft power systems has led to interest in DC electrical networks for aircraft applications. This paper investigates a wound-field synchronous generator and uncontrolled diode rectifier as the DC source and analyses the power quality of the AC and DC sides of the rectifier. The paper gives expressions for voltage and current distortion for a multiphase generator as a function of the number of phases. For a star-connected machine, the power quality on the AC side is shown to deteriorate rapidly as the phase number increases, resulting in increased losses and a higher rating requirement. A delta connection provides better utilisation of the generator; however, at the expense of the fault tolerance. Mathematical models for the multiphase system are developed and the analysis is supported by simulation results; verified through laboratory testing. © 2011 IEEE.

We present the results of systematic studies of ion current rectification performed on artificial asymmetric nanopores with different geometries and dimensions. The nanopores are fabricated by the ion track etching method using surfactant-doped alkaline solutions. By varying the alkali concentration in the etchant and the etching time, control over the pore profile and dimensions is achieved. The pore geometry is characterized in detail using field-emission scanning electron microscopy. The dependence of the ion current rectification ratio on the pore length, tip diameter, and the degree of pore taper is analysed. The experimental data are compared to the calculations based on the Poisson-Nernst-Planck equations. A strong effect of the tip geometry on the diode-like behaviour is confirmed. © 2011 IOP Publishing Ltd., The authors thank O M Ivanov for the irradiation of the polymer foils with accelerated ions. The help of V A Kuzmin with the calculations is appreciated. PR thanks the Ministerio de Ciencia e Innovacion (MCINN-Spain, project MAT2009-07747) for financial support.

Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-27T11:25:28Z No. of bitstreams: 0Bitstream added on 2014-05-27T14:47:09Z : No. of bitstreams: 1 2-s2.0-79953312647.pdf: 680474 bytes, checksum: 9b68e8c0a98b793ce278013a972fb9e4 (MD5) Made available in DSpace on 2014-05-27T11:25:28Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-02-01 Multipulse rectifier topologies based on auto-connections or differential connections, are more and more applied as interface stages between the mains and power converters. These topologies are becoming increasingly attractive not only for robustness, but to mitigate many low order current harmonics in the utility, reducing the total harmonic distortion of the line currents (THDi) and increasing the power factor requirements. Unlike isolated connections (delta-wye, zigzag, etc.), when the differential transformer is employed, most of the energy required by the load is directly conducted through the windings. Thus, only a small fraction of the kVA is processed by the magnetic core. This feature increases the power density of the converter. This paper presents a mathematical model based on phasor diagrams, which results in a single expression able to merge all differential connections (wye and delta), for both step-up and step-down rectifiers for 12 or 18 pulses. The proposed family of converters can be designed for any relationship between the line input voltage and the DC voltage, unlike the conventional phase-shift voltage connections. An immediate application would be the retrofit, i.e. to replace a conventional rectifier with poor quality of the processed energy by the 12 or 18-pulse rectifiers with Wye or Delta-differential connections, keeping the original values for the input and load voltages. The simple and fast design procedure is developed and tested for a prototype rating 6 kW and 400 V on DC load. UNESP - Univ. Estadual Paulista Departamento de Engenharia Elétrica Campus de Ilha Solteira, SP UNESP - Univ. Estadual Paulista Departamento de Engenharia Elétrica Campus de Ilha Solteira, SP

This paper presents a comparative study of several speed estimators to implement a sensorless speed control loop in Wind Energy Generation Systems driven by power factor correction three-phase boost rectifiers. This rectifier topology reduces the low frequency harmonics contents of the generator currents and, consequently, the generator power factor approaches unity whereas undesired vibrations of the mechanical system decrease. For implementation of the speed estimators, the compared techniques start from the measurement of electrical variables like currents and voltages, which contain low frequency harmonics of the fundamental frequency of the wind generator, as well as switching frequency components due to the boost rectifier. In this noisy environment it has been analyzed the performance of the following estimation techniques: Synchronous Reference Frame Phase Locked Loop, speed reconstruction by measuring the dc current and voltage of the rectifier and speed estimation by means of both an Extended Kalman Filter and a Linear Kalman Filter. © 2010 Elsevier Ltd., The first author thanks the support of the Instituto Politecnico Nacional (IPN) to finance his stay at the Universidad Politecnica de Valencia (UPV). This work was supported by the Spanish Ministry of Science and Innovation under Grant ENE2009-13998-C02-02.

In this work a technology to fabricate low-voltage amorphous gallium-indium-zinc oxide thin film transistors (TFTs) based integrated circuits on 25 mu m foils is presented. High performance TFTs were fabricated at low processing temperatures (< 150 degrees C) with field effect mobility around 17 cm(2)/V s. The technology is demonstrated with circuit building blocks relevant for radio frequency identification applications such as high-frequency functional code generators and efficient rectifiers. The integration level is about 300 transistors. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3579529] ispartof: Applied Physics Letters vol:98 issue:16 status: published

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 transport, and this blocking effect can be exploited to tune the conductance and selectivity of the nanopore in aqueous solution. Both cylindrical and conical nanopores were used in the experiments. The possibility of obtaining two or more conductance states (output), dictated by the degree of nanopore blocking resulted from the different biomolecules in solution (input), as well as the current rectification properties obtained with the conical nanopore, could also allow implementing information processing at the nanometre scale. Model simulations based on the transport equations further verify the feasibility of the sensing procedure that involves concepts from supramolecular chemistry, molecular imprinting, recognition, and nanotechnology. © 2011 The Royal Society of Chemistry.

In this work a technology to fabricate low-voltage amorphous gallium-indium-zinc oxide thin film transistors (TFTs) based integrated circuits on 25 µm foils is presented. High performance TFTs were fabricated at low processing temperatures (

Single-track, asymmetric nanopores can currently be functionalised with a spatially inhomogeneous distribution of fixed charges and a variety of pore tip shapes. Optimising the asymmetric nanopore characteristics is crucial for practical applications in nanofluidics. We have addressed here this question for three cases based on different input/output chemical and electrical signals: (i) ion pumping up a concentration gradient by means of a periodic, time-dependent bias potential, (ii) information processing with a single nanopore acting as the nanofluidic diode of a logic gate, and (iii) electrical energy harvesting using a nanopore that separates two solutions of different salt concentrations. The results show the nanopore characteristics (size, shape, and charge distribution) that should be optimised for each application. In particular, the control of the pore tip size and charge appears to be crucial in all cases because it is in this narrow region where the interaction of the ions and the pore surface occurs, and this will eventually determine the nanodevice performance. © 2011 Elsevier Ltd. All rights reserved., We acknowledge the financial support from the Ministry of Science and Innovation of Spain and FEDER, Programme of Materials (project No. MAT2009-07747).

A 64b inductively coupled organic RFID tag on foil is demonstrated at 13.56MHz. The digital logic foil comprises 414 pentacene transistors and is powered by a pentacene double half-wave rectifier, connected to an inductive antenna. The data rate is 787b/s with load modulation behind the rectifier (DC). Also shown is a functional AC-modulated organic RFID tag. ©2008 IEEE. ispartof: pages:290-291 ispartof: Proceedings of the IEEE International Solid-State Circuits Conference - ISSCC vol:51 pages:290-291 ispartof: IEEE International Solid-State Circuits Conference - ISSCC location:San Francisco, CA USA date:3 Feb - 3 Feb 2008 status: published

A 64b inductively coupled organic RFID tag on foil is demonstrated at 13.56MHz. The digital logic foil comprises 414 pentacene transistors and is powered by a pentacene double half-wave rectifier, connected to an inductive antenna. The data rate is 787b/s with load modulation behind the rectifier (DC). Also shown is a functional AC-modulated organic RFID tag. ©2008 IEEE.

In this study, a novel voltage-mode full-wave rectifier with high-input impedance using a dual-X second-generation current conveyor and three enhancement-type n-channel metal-oxide semiconductor field-effect transistors (MOSFETs) is introduced. The proposed circuit does not employ any passive elements, and is simulated using SPICE program with level 49, 0.25 mu m TSMC CMOS technology parameters to confirm the theory and exhibit the performance of the circuit.

Coordinate pulsewidth modulation is considered for the control of power switches of matrix and two-component direct frequency converters (DFC) in ac drive systems. The synthesis of modulating signals yielding the specified output voltages and sinusoidal grid currents for converters with no intermediate smoothing filter is discussed. Simulation of DFC operation with an RLE load and an asynchronous motor is undertaken.