Output Voltage Characteristics Research Articles

Setting of SOI MOSFET Model Parameters based on BP Neural Networks Algorithm

With development of SOI technology, SOI MOSFET technology is developed as well. Most traditional MOSFET parameter models adopt semi-empirical and semi-physical model, and simplification assumption is introduced during modeling. However, as SOI MOSFET devices keep downsizing, the short-channel effect and quantum effect are more obvious so that it is more complicate to calculate and extract characteristic parameters of SOI MOSFET. This paper proposes a kind of SOI MOSFET characteristic parameter modeling method based on BP neutral networks algorithm. Compared to other semi-empirical models, this method needs not to calculate characteristic parameters of devices. In stead, it calculates current and voltage output characteristics and transfer characteristics of devices through BP neutral network models according to test data. Through verification, the trained and predicted output relative error is within 5%. The model has short operation time, high calculation precision and good stability. The models established may be applied extensively to other types of transistor, and feasible for practical engineering application.

Comparative Study on III-V MOSFET and Si-MOSFET Model Parameters based on BP Neural Networks Algorithm

MOSFET is the basic unit of modern integrated circuit, and main basic characteristics are: current-voltage (IV) characteristics, capacitor-voltage (CV) characteristics and source-drain contact characteristics. The introduction of group III-V semi-conductor, high k- metal date and SBSD allows MOSFET device characteristic device may keep downsizing based on Moore’s Law. However, as II-V MOSFET devices keep downsizing, the short-channel effect and quantum effect are more obvious so that it is more complicate to calculate and extract characteristic parameters of III-V MOSFET. This paper proposes a kind of III-V MOSFET characteristic parameter modeling method based on BP neutral networks algorithm. Compared to other semi-empirical models, this method needs not to calculate characteristic parameters of devices. In stead, it calculates current and voltage output characteristics and transfer characteristics of devices through BP neutral network models according to test data. Through verification, the trained and predicted output relative error is within 5%. The model has short operation time, high calculation precision and good stability. The models established may be applied extensively to other types of transistor, and feasible for practical engineering application.

Investigation of output voltage, vibrations and dynamic characteristic of 2DOF nonlinear functionally graded piezoelectric energy harvester

With the aim of providing the larger frequency band and progress the energy harvesting proficiency of the bistable piezoelectric energy harvester (BPEH), a 2-DOF nonlinear distributed parameter model of BPEH with an elastic magnifier is considered in this paper. This study deals with bimorph beam with functionally graded piezoelectric (FGP) layers carrying concentrated mass at tip while taking into account the geometrical nonlinear terms and the nonlinear magnetic force to enhance energy harvesting performance. By presenting the magnifier, oscillations of the tip are inspired into high-energy orbits. Mathematical model of BPEH with a dynamic magnifier has been developed, then the nonlinear coupled equation of motion derived using Hamilton principle. Initially, frequency response of harvester derived according to harmonic balance method and the adjusted model has been confirmed by parametric studies of earlier lumped parameter model. Analytical results show that the harvesting voltage can be improved with correct selection of design parameters of the magnifier. The proposed 2-DOF harvester system can provide higher output over a wider frequency band and may cause a considerable change in harvester performance. A parametric study is consummated to expose the effects of power law index of FGP on the output voltage and dynamic characteristic.

DC–DC converter implementation with wide output voltage operation

A direct current (DC) to DC converter with soft switching and high efficiency is developed for industry power units with a wide range of output voltage applications. A series resonant converter is the main circuit on the primary side to accomplish the soft switching characteristics for the active devices and rectifier diodes without switching loss or reverse recovery current loss. To overcome the drawback of the limited operation input or output voltage range in conventional LLC converters, a hybrid resonant converter including a half-bridge circuit and a full-bridge circuit with auxiliary windings is developed to achieve 8:1 (Vo,max = 8Vo,min) output voltage characteristics for a wide range of output voltage applications. To achieve this function, two AC power switches are used in the developed circuit. Since a single-stage hybrid resonant converter is presented instead of a two-stage converter to realize wide voltage range operation, the developed circuit has better efficiency when compared to conventional LLC converters and two-stage DC–DC converters. To confirm the circuit analysis and effectiveness, a prototype with a 400 W rated power was built and tested.

The Charging Control and Efficiency Optimization Strategy for WPT System Based on Secondary Side Controllable Rectifier

The equivalent resistance of the battery will change during charging in practical applications, so it is difficult to design a wireless power transfer (WPT) system with accurate constant current (CC) and constant voltage (CV) output characteristics. In addition, the WPT system efficiency is also affected by the change of equivalent resistance. Therefore, this paper studies the charging control and efficiency optimization strategy for the WPT system with dynamic loads. The WPT system with a structure of double-sided LCC compensation topology and containing controllable rectifier circuit at the secondary side is established, and the working process of full-bridge controllable rectifier circuit is analyzed. Then the output characteristics of the WPT system are analyzed. The expressions of the optimal transmission efficiency and the optimal equivalent impedance of the full-bridge rectifier are derived. The relationships between the equivalent impedance of the capacitor-filtered full-bridge controllable rectifier circuit and the phase shift angle, the charging current and the phase shift angle are also obtained. In this paper, the CC and CV charging strategies based on phase shift control of controllable rectifier circuit and efficiency optimization strategy based on dynamic equivalent impedance matching are proposed, which can improve the WPT system transmission efficiency while realizing CC and CV charging. Finally, the effectiveness of the proposed control strategy is verified by simulation and experiment. The WPT system realizes CC charging mode and CV charging mode in turn when the load resistance changes from $5~\Omega $ to $30~\Omega $ , and the overall efficiency is up to 90.71% at the transmission distance of 15cm.

Micro-power-generator for energy harvesting from vortex induced vibration

A micro-power-generator is developed with piezoelectric ceramics, which can convert the structural vibration energy generated by wind power into electricity to provide energy for micro-devices such as wireless sensor nodes. The vibration modes of the device are analyzed. The standard interface circuit for piezoelectric energy recovery and LTC3588-1 voltage stabilization circuit are selected, and the hardware circuit of the device is designed. The output voltage and power characteristics of micro-power-generator were analyzed under different loads, frequencies and amplitudes. The experimental results show that under the same wind speed, When the blunt body is a cuboid, the power generation effect of this device is the best under the optimal load, with the maximum output power of 350.7 μW. Under the same load with the same shape and structure, the load voltage and output power increase with the increase of wind speed.

Fabrication of potassium sodium niobate nano-particle/polymer composites with piezoelectric stability and their application to unsteady wind energy harvesters

We investigated the effects of poling conditions on the piezoelectric performance of potassium sodium niobate [(K,Na)NbO3, KNN]/polymer composites, to obtain their unsteady energy harvesting potential. KNN nanoparticle/polymer composites were designed and fabricated and the poling condition test was performed. The composites were polarized using the corona poling method for various poling conditions and then the piezoelectric coefficient d33 was measured. It was found that piezoelectricity does not decrease over days. Scanning electron microscopic observations were conducted to study the distribution of the nanoparticles in the matrix. Meanwhile, the microstructure of the composites was studied by X-ray diffraction. Unsteady wind energy harvesting tests were accomplished to investigate the output voltage characteristics in the KNN nanoparticle/polymer composites in unsteady winds. The study represents an important step in developing flexible energy harvesters with stable performance.

Design and development of Cu–Al–Mn shape memory alloy coated optic fiber sensor and its actuation characteristics for condition monitoring of structures

In this work, Cu-based shape memory alloy-coated optic fiber has been fabricated for condition monitoring and temperature-sensing applications. Cu–8.0Al–10.0Mn (wt.%) shape memory alloy has been coated over optical fiber using custom-made flash evaporation setup. An in situ fixture with rotating drive setup has been designed and developed for uniform coating. SEM, XRD, and DSC results have confirmed the uniformity, crystallinity, and phase transformation of the SMA-coated optic fiber. At 285 °C austenite phase, transformation has confirmed using differential scanning calorimetry. Thermo-optic test bench has been developed to study the output voltage and actuation characteristics of the developed smart fiber optic sensor. Experiments were performed to investigate the light intensity in the SMA-coated optical fiber at different actuation conditions.

Design of Power Converter for Aluminum Air Battery

In order to improve the output voltage performance of the aluminum air battery and improve the conversion efficiency, according to the output voltage characteristics of the aluminum air battery pack, we propose an LLC resonant converter based on integral separation PID control and voltage feedforward control. Then the main parameters of the converter were designed and finally simulated by MATLAB/Simulink. The experiment proves that the control method adopted by the aluminum air battery converter effectively improves the dynamic performance index of the system compared with the conventional PID control.

High boost‐ratio bidirectional converter for interfacing low‐voltage battery energy storage system to a DC bus

Supply and demand mismatches in renewable energy systems are addressed by integrating battery banks. Selecting battery bank terminal voltage to match DC-bus voltage (350–450 V for single-phase AC loads), necessitates employing battery banks with long-string connections along with their attendant shortcomings. To employ short-string battery banks, high-boost-ratio bidirectional interfaces are required between the DC-bus and battery bank. Current literature lacks a single source where high-boost-ratio converters’ are categorised and their strengths and weaknesses identified. Comprehensive literature review is hence carried out to determine attributes of various high-boost-ratio DC–DC converters and also categorise them. The key attributes of a topology to interface battery storage to a DC-bus are determined. Based on these a bidirectional tapped-inductor boost converter emerges as the best candidate. Moreover, in order to regulate output voltage, voltage-gain versus duty-ratio characteristics should not be very steep. Since battery terminal voltage varies with state-of-charge, closed-loop control is necessary. Converter's small-signal transfer-functions are derived and a two-loop controller to regulate output voltage and inductor current while allowing bidirectional power flow designed. A novel bidirectional passive lossless snubber circuit is employed to clamp the voltage spikes across the active switches, without altering the normal operation of the converter.

Influence of AlN etching process on MISFET structures

Purpose The purpose of this paper is to present the influence of gate dielectric etching on obtained MISFET (metal insulator semiconductor field effect transistor) structures. Because of its properties, aluminum nitride (AlN) layers can be successfully used in a large area of applications. In addition, AIN has a wide bandgap (6.2eV) and high thermal conductivity (3.2 W/cm * K). Its melting temperature is greater than 2,000°C. The relative permittivity is about 9. All these features (especially high power, high temperature and high-frequency) make AlN a useful material in the fields of electronic, optical and acoustic applications. Design/methodology/approach To fabricate n-channel transistors, silicon technology was used. The 50-nm thick AlN films were deposited using the magnetron sputtering. After preparation of SiO2/AlN stack as the gate dielectric, the optimization processes of dry etching in plasma environment by Taguchi method were realized. In the next step, three methods of AlN etching were selected and used to MISFET device fabrication. Atomic force microscopy and scanning electron microscopy allowed to surfacing of the state observation after etching process. The current–voltage (I–V) output and transfer characteristics of structures with modified etch technology were measured. Keithley SMU 236/237/238 measurement set was used. Findings In this research work, a method of AlN etching in a field effect transistor technology was developed and improved. Current−voltage characteristics of obtained MISFET structures were measured and compared. Influence of etching procedure on transistors properties was examined. Originality/value The obtained results allow improving the MISFET technology based on AlN film as a gate dielectric. The complete research work will allow using the developed technologies to implement in highly sensitive ion-sensitive field effect transistor (ISFET) structures in the future. The improvement of the etching element in the technology strongly influences the detection capabilities and operating range of the transistor.

Study on Impact of Parasitic Capacitance on Performance of Graded Channel Negative Capacitance SOI FET at High Temperature

This paper focuses on studying the impact of parasitic capacitance ( ${C}_{p}$ ) on the performance of nanoscale graded channel (GC) negative capacitance (NC) silicon-on-insulator (SOI) FET at elevated temperatures. The device performance has been extensively explored for a range of ${C}_{p}$ values for temperature range 300–400 K by employing simulation framework that uses TCAD models with Landau Khalatnikov equation. The advantages of GC design and NC phenomenon have been investigated for a wide temperature range and optimum values of ${C}_{p}$ have been obtained to achieve substantial enhancement in key device parameters such as differential voltage amplification, subthreshold swing (below 60 mV/dec), transconductance, transconductance efficiency, output characteristics, and unity gain frequency.

A Dual Half-Bridge LLC Resonant Converter With Magnetic Control for Battery Charger Application

In this paper, a dual half-bridge LLC resonant converter with magnetic control is proposed for the battery charger application. The primary switches are shared by two LLC resonant networks, and their outputs are connected in series. One of the LLC resonant converters is designed to operate at the series resonant frequency, which is also the highest efficiency operating point, and the constant output voltage characteristic is achieved at this operating point. The second LLC resonant converter adopts magnetic control to regulate the total output current and voltage during both constant current charge mode and constant voltage charge mode. Meanwhile, the function decoupling idea is adopted to further improve the system efficiency. The significant amount of the power is handled by the LLC resonant converter operating at the series resonant frequency, whereas the second LLC resonant converter fulfills the responsibility to achieve closed-loop control. By carefully designing the resonant networks, the zero-voltage switching for primary switches and zero-current switching for secondary diodes can be achieved for whole operation range. A 320-W experimental prototype is built to verify the theoretical analysis, and the maximum efficiency is measured about 95.5%.

A Study of Over-modulation Impact on the MSI Series Micro-Grid Output Voltage

In order to analyse the over-modulation technique impact on the micro-source inverter (MSI) series micro grids (SMGs) output voltage, firstly Double Fourier method applied to derive the single inverter output voltage characteristics under over-modulation condition; Secondly, based on the characteristics of the MSI series micro-grids, a new formula of the system output voltage is derived. Thirdly, the impact on the system output voltage fundamental component and harmonic component is analysed in detail, the results show that the output voltage fundamental component increases with the increasing modulation while keeps constant after a certain over-modulation depth. Finally, a simulation was carried out and the simulation verified the theoretical analysis.

Autotuning Control System by Variation of Self-Inductance for Dynamic Wireless EV Charging With Small Air Gap

In this paper, an autotuning control system (ACS), which utilizes the variation of self-inductance of a transmitter (Tx) coil caused by a ferrite core of a receiver (Rx), is newly proposed for the dynamic wireless electric vehicle (EV) charging. A Tx module consists of only passive elements that include a Tx coil, a partially compensated capacitor in series with the Tx coil, and a parallel compensation capacitor. All Tx modules share an ac bus line that passes the output filter of an inverter in parallel without any active switches. The current of the coupled Tx coil increases automatically without any manipulations such as controlling the power switches, sensing, or communication when the Rx module is approaching. Not only the system efficiency is increased by the reduction of the conduction losses from the uncoupled Tx modules, but control also becomes simpler because sensors are not required for detecting EVs, and the constant output voltage characteristics can be obtained. Through experiments, it was found that the proposed ACS is suitable for applications such as a tram that runs along an orbit with a small air gap, such as a train. The results showed that the current of a coupled Tx coil increased 11.6 times larger than that of an uncoupled Tx coil, at which time the dc–dc efficiency achieved was 88.4% for an output power of 766 W (10 Ω of load resistance) at the laboratory scale.

An Eight-Zonal Piezoelectric Tube-Type Threaded Ultrasonic Motor Based on Second-Order Bending Mode

In order to reduce the driving voltage and gain better output characteristics of piezoelectric actuators, an eight-zonal piezoelectric tube-type threaded ultrasonic motor based on two second-order bending modes was analyzed using the method of finite element analysis (FEA), and a prototype was fabricated and experimentally studied in this research. This piezoelectric motor was designed to be excited by four electrical sources applied simultaneously to four groups of electrodes on the customized lead zirconate titanate (PZT) tubular stator (inside diameter 5.35 mm, outside diameter 6.35 mm, length 30 mm), with ±90° phase shifts between adjacent electrodes. Experimental results show that the threaded motor could output a stall force (stall force means the output pull or thrust force when the linear speed is set to be zero) of about 5.0 N and a linear velocity of 4.9 mm/s with no load at the driving voltage of 40 Vpp (Vpp means the peak-to-peak value of the voltage volts). This piezoelectric motor with a compact structure and screw drive mechanism shows relatively fine velocity controllability and has huge superiority in micro-positioning systems.

Wearable Core-Shell Piezoelectric Nanofiber Yarns for Body Movement Energy Harvesting.

In an effort to fabricate a wearable piezoelectric energy harvester based on core-shell piezoelectric yarns with external electrodes, flexible piezoelectric nanofibers of BNT-ST (0.78Bi0.5Na0.5TiO3-0.22SrTiO3) and polyvinylidene fluoride-trifluoroethylene (PVDF-TrFE) were initially electrospun. Subsequently, core-shell piezoelectric nanofiber yarns were prepared by twining the yarns around a conductive thread. To create the outer electrode layers, the core-shell piezoelectric nanofiber yarns were braided with conductive thread. Core-shell piezoelectric nanofiber yarns with external electrodes were then directly stitched onto the fabric. In bending tests, the output voltages were investigated according to the total length, effective area, and stitching interval of the piezoelectric yarns. Stitching patterns of the piezoelectric yarns on the fabric were optimized based on these results. The output voltages of the stitched piezoelectric yarns on the fabric were improved with an increase in the pressure, and the output voltage characteristics were investigated according to various body movements of bending and pressing conditions.

A 1-GS/s, 12-b, Single-Channel Pipelined ADC With Dead-Zone-Degenerated Ring Amplifiers

Ring amplification has recently been shown capable of simultaneously achieving high linearity and high bandwidth (BW) in low-voltage, deep nanoscale CMOS processes, while retaining good power efficiency. In these processes, the low but very flat open-loop (OL) gain versus output voltage characteristic of the ring amplifier can be exploited, together with its high BW, to overcome the low intrinsic gain limitations that otherwise mandate the use of power-consuming analog circuits and complex digital calibration. Within this context, this paper introduces the techniques of dead-zone degeneration (DZD) and second-stage bias enhancement to further extend the linearity and speed limits of the ring amplifier, respectively. These techniques are applied to a 12-b, 1-GS/s, single-channel pipelined ADC implemented in a 28-nm planar CMOS process, which achieves 56.6-dB SNDR and 73.1-dB SFDR while consuming 24.8 mW from a single 0.9-V supply, resulting in Schreier and Walden figure-of-merit (FoM) values of 159.6 dB and 45 fJ/conv.-step, respectively.

Slotless tubular PM generator with dual quasi‐Halbach magnetized PM Array: Analytical and numerical magnetic field analysis

AbstractIn this paper, an initial design and analytical electromagnetic field solution for Slotless and Dual Quasi‐Halbach (DQH) Permanent Magnet mover is proposed for reciprocating free piston alternator application. Utilizing presented analytical magnetic field solution, Air‐Gap magnetic flux characteristic, and generated voltage are estimated. Using 3‐D finite‐element method (FEM) proposed structure numerically investigated and obtained numerical results employed to confirm the derived analytical models. The analytical results are compared with FEM and show excellent agreement. In order to determine output voltage and power characteristics, the load testing has been performed by a resistive variable load. The obtained results from FEM analysis and analytical magnetic field solution show an enhancement in the proposed alternator performance compared with the alternator with Halbach magnetized configuration, by improving provided power.

A Single-Channel, 600-MS/s, 12-b, Ringamp-Based Pipelined ADC in 28-nm CMOS

Achieving high linearity and bandwidth with good power efficiency makes the design of ADCs in deep nanoscale CMOS processes very challenging, as the constraints of low-voltage operation and limited intrinsic gain often dictate the use of power-consuming analog circuits and intensive digital calibration. This paper addresses these problems by introducing a pipelined ADC that exploits the low but very constant open-loop gain versus output voltage characteristic of the ring amplifier (ringamp) to achieve both high speed and linearity in low-voltage nanoscale CMOS designs. A tunable ringamp biasing scheme using an anti-parallel arrangement of CMOS transistors and an active ringamp-based common-mode feedback are also introduced. A single-channel prototype ADC is implemented in a standard 28-nm CMOS process, achieving 58.7-dB SNDR and 72.4-dB SFDR at 600 MS/s while consuming 14.5 mW from a single 0.9-V supply, resulting in Walden and Schreier figure-of-merit (FoM) values of 34.4 fJ/conv.-step and 161.9 dB, respectively.