High Power Characteristics Research Articles

Design of Testable Reversible Memory Circuits

Quantum dot Cellular Automata (QCA) is the new possibility for the future of nano-electronic computing technology which employs the principle of quantum mechanics. This paper, contributes to the design of Memory circuits based on conservative reversible logic gates & also the design is made testable using two test vectors. The conservative logic gates dominates the classical gates in terms of testability, feature size scaling & high power consumption for the design of sequential circuits. Here the Memory circuits (1-bit, 4-bit & 8-bit) are designed by employing conservative logic gates(Fredkin Gate), which is being simulated and tested for the detection of unidirectional stuck-at faults using two test vectors 0s & 1s. For the simulation of the described designs Xilinx's 8.2 EDA tool is used.

High-temperature and high-power piezoelectric characteristics of (Bi<sub>0.5</sub>Na<sub>0.5</sub>)TiO<sub>3</sub>-Based lead-free piezoelectric ceramics

High-temperature and high-power piezoelectric characteristics of (Bi<sub>0.5</sub>Na<sub>0.5</sub>)TiO<sub>3</sub>-Based lead-free piezoelectric ceramics

ChemInform Abstract: Recent Progress in Supercapacitors: From Materials Design to System Construction

AbstractReview: 54 refs.

A Wideband Power Amplifier in 45 nm CMOS SOI Technology for X Band Applications

A fully-integrated wideband power amplifier (PA) operating in 9-15 GHz range is implemented in a standard 45 nm CMOS SOI technology. The PA is designed with three dynamically-biased stacked Cascode cells (6 stacked transistors) to overcome the low breakdown voltages of nanoscale CMOS transistors. The stacked Cascode cells ensure stable operation and facilitate high gain, and high optimum load impedance, leading to high output power, high efficiency and good linearity characteristics over the entire bandwidth. The unbalanced amplitude and phase of drain-source voltage signals caused by internodal parasitic capacitance are equalized by adjusting the sizing of transistors. With a supply voltage of 4.8 V at 12 GHz, the measured saturated output power and linear power are 22.5 dBm and 19.2 dBm, respectively, while the peak power-added efficiency (PAE) is 19.2%. At a reduced power supply of 3.6 V, the PA achieves peak PAE of 25.7% where the drain efficiency reaches 40.7%. Including its pads, the PA occupies a compact chip area of 0.22 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> .

Reduction of Cogging Torque in Claw Pole Machines Using Soft Magnetic Composites

The use of soft magnetic composites (SMC) allows the design of complex motor geometries while maintaining low manufacturing costs. Typical applications for SMC are electric machines with three-dimensional flux paths. The claw pole machine (CPM) is a typical representative of this group of machines and features high power density and a simple winding design, hence making these motors very interesting for the automotive industry. Unfortunately, CPMs are prone to significant cogging torque due to the construction constraints they bring along. In this paper, the cogging torque of an existing claw pole machine is analyzed, using 3D finite element (FE) simulation. Especially the influences of manufacturing tolerances are investigated. Further, a new rotor design with reduced cogging torque using embedded magnets is introduced. Finally, the measurement results of a CPM-prototype featuring the new rotor design are presented and compared to the results of the 3D-FE simulation.

Thermal Characteristics of High-Power LED Packages with Dissipation Film

A simple, fast, and reliable characterization method for measuring junction temperature (Tj) on high power GaN-based light emitting diodes (LED) was presented in this study. Thermal characteristics of high power Light-emitting-diode have been analyzed by using a three-dimensional thermal conduction model. Maximum operation temperature has also been calculated. The induced thermal behaviors of the best package processes for LED device with diamond film were investigated by finite element analysis (FEA) and by experimental measurement. The large change of forward operation voltage with temperature in light emitting diodes is advantageously used to measure junction temperature. Using this method, junction temperature (Tj) of LED under various structures and chip mounting methods was measured. It was found that the junction temperature can be reduced considerably by using diamond film substrates to replace sapphire substrate. In this study, the junction temperature can be decreased by about 14.3% under 1.5W power and decreased by about 15.9% under 1W power for 1mm square die. The thermal resistance (RT) can be measured to be 14.8°C/W under 1.5W power and 16.6°C/W under 1.W power.

Design of a 6502-Compatibable Microprocessor

An embedded microprocessor core used for ASIC is presented, which is compatible with 6502 microprocessor. Simulation shows that the timing sequence of the circuit meets the requirement of 6502 microprocessor. The device features high speed and low power consumption.

Recent Progress in Supercapacitors: From Materials Design to System Construction

Supercapacitors are currently attracting intensive attention because they can provide energy density by orders of magnitude higher than dielectric capacitors, greater power density, and longer cycling ability than batteries. The main challenge for supercapacitors is to develop them with high energy density that is close to that of a current rechargeable battery, while maintaining their inherent characteristics of high power and long cycling life. Consequently, much research has been devoted to enhance the performance of supercapacitors by either maximizing the specific capacitance and/or increasing the cell voltage. The latest advances in the exploration and development of new supercapacitor systems and related electrode materials are highlighted. Also, the prospects and challenges in practical application are analyzed, aiming to give deep insights into the material science and electrochemical fields.

Shape optimization of reconfigurable antenna reflectors

The active mechanical reshaping of the antenna reflector is considered a good candidate for in-orbit coverage reconfigurability that is required by the Telecom and Earth Observation missions since it features low cost, low mass and high power capability as compared to the active array antenna technology. However, to guarantee the stability and strength of the reflector under both constant actuation and exposure to the space environment, it is necessary to minimize the stresses and strains that arise when the reflector is reshaped. This article presents a methodology for the antenna reflector shape optimization, in which the cost function is the maximum value of the strain in the reflector and, where the radio-frequency (RF) and the actuation requirements are imposed as constraints. The performance at each iteration of actuator displacements is analyzed by the finite element method to compute the overall shape of the reflector, the strains arising and the actuator forces and by physical optics to compute the RF pattern radiated by the reflector shaping. Simulated annealing, as a global optimization method, has been selected for the optimization algorithm, since it allows escaping from local minima and benefits from the existence of starting points for the global optimization, that have resulted from pure RF optimization. A drastic reduction of strains in the reflector has been achieved, while the RF and actuation requirements have been met. These are key results to the development of actively reshapable reflectors.

Modulation Scheme for Improved Operation of an RB-IGBT-Based Resonant Inverter Applied to Domestic Induction Heating

Domestic induction appliances require power converters that feature high efficiency and accurate power control in a wide range of operating conditions. To achieve this modulation techniques play a key role to optimize the power converter operation. In this paper, a series resonant inverter featuring reverse-blocking insulated gate bipolar transistors and an optimized modulation technique are proposed. An analytical study of the converter operation is performed, and the main simulation results are shown. The proposed topology reduces both conduction and switching losses, increasing significantly the power converter efficiency. Moreover, the proposed modulation technique achieves linear output power control, improving the final appliance performance. The results derived from this analysis are tested by means of an experimental prototype, verifying the feasibility of the proposed converter and modulation technique.

Peak power reduction and energy efficiency improvement with the superconducting flywheel energy storage in electric railway system

This paper proposes an application of the 100kWh superconducting flywheel energy storage systems to reduce the peak power of the electric railway system. The electric railway systems have high-power characteristics and large amount of regenerative energy during vehicles’ braking. The high-power characteristic makes operating cost high as the system should guarantee the secure capacity of electrical equipment and the low utilization rate of regenerative energy limits the significant energy efficiency improvement. In this paper, it had been proved that the peak power reduction and energy efficiency improvement can be achieved by using 100kWh superconducting flywheel energy storage systems with the optimally controlled charging or discharging operations. Also, economic benefits had been assessed.

A Tunable Blue Light Source with Narrow Linewidth for Cold Atom Experiments

We present a 397-nm frequency-doubling system with a quasi-phase-matched KTP crystal (PPKTP) which features tunable, narrow linewidth, high power, and excellent mechanical stability. Using 20-mm and 30-mm-long PPKTP crystals, we establish two experimental setups based on different external cavity parameters. By testing the beat signal of these two lasers, the linewidth for the system is measured to be less than 2.5 MHz. The maximum power of blue light can be achieved up to 40 mW. With these performance characteristics, the constructed blue laser system is useful for applications in cold atom physics and precision measurements.

大功率空间椭圆光束整形和传输研究

Slab laser has characteristics of high output power and high beam quality.However,the far field facula of its primitive outgoing beam presents as an oval,and its far field divergence angle is slightly big which makes it inconvenient to transmit in very long distance.To solve this problem,a cylindrical telescope system with optimized parameter was used to expand the x-scale outgoing beam(wide divergence angle).The goal is to make the x-scale divergence angle approximate to the y-scale divergence angle which is a small angle,and constrain the beam waist position of x-scale and y-scale to the same place in case of out of focus.The general sphere beam expander was used to compress far field divergence angle of the reshaped beam.At last,the laser beam with a far field divergence angle less than 100μrad and ratio of x-scale to y-scale less than1.1in out-field experiment was obtained.

Facile synthesis of NiMoO4·xH2O nanorods as a positive electrode material for supercapacitors

NiMoO4·xH2O nanorods with one-dimensional structures and high performances are synthesized by a facile chemical co-precipitation method. A maximum specific capacitance of 1136 F g−1 is achieved at a current density of 5 mA cm−2. The fabricated NiMoO4·xH2O is a good positive electrode material for supercapacitors due to its unique structure and excellent capacitive properties. To enhance the energy density and enlarge the potential window, an asymmetric supercapacitor is assembled using NiMoO4·xH2O as the positive electrode and activated carbon (AC) as the negative electrode in 2 M aqueous KOH electrolyte. It exhibits a high energy density and stable power characteristics. A maximum specific capacitance of 96.7 F g−1 and specific energy of 34.4 W h kg−1 are demonstrated for a cell voltage between 0 and 1.6 V, indicating that the fabrication of an asymmetric supercapacitor is an effective way to enhance the energy density.

218 磁歪式振動発電デバイスを用いた低周波数振動で動作する無線センサシステムに関する研究(セッション8 ボルト緩み評価診断・橋梁点検)

We are developing vibrational energy harvesting system using iron-based magnetostrictive material (Galfenol) utilized as power supply for wireless sensor module of automobile and industrial machinery. The harvester consisting of Galfenol plate wound with coil, yoke and magnet features simple, small, highly robust and high power output. Our conventional harvester based on cantilever can generate high power output at high frequency resonance, however, does not match the use in automobile and industrial machinery with 10w frequency vibration. In this paper, we propose harvester equipped with adjusting tip mass mechanism and resonator for the operation in low frequency vibration. The harvester with the mechanism has three low frequency resonances determined by tip mass, mass and spring of the resonator. We verified the prototype using Galfenol plate of 2 by 0.5 by 22 mm with the mechanism (tip mass of 7.4g) has resonant frequency around 63 Hz and can generate high power output at low frequency and wide bandwidth.

Regulation of detonation ability of explosive materials used in spacecraft separation systems

Approaches to the regulation of the detonation ability of explosive materials, especially elastic explosives used in spacecraft separation systems, are considered. The new method of regulation, which implies the use of binary mixtures of fine-grained crystal elastic explosives as part of the explosive, one of which has high power characteristics and the other a small critical diameter of detonation, is offered.

The Application of Super Capacitor in Scenery Generator Energy Storage System

Based on the comparison of battery energy storage system, super capacitor energy storage system, superconducting storage system, flywheel energy storage system, hybrid energy storage system composed by battery and super capacitor is proposed. By Analysis the performance of the system, it can be know that the system has characteristics of high specific power and high specific energy, and the battery and super capacitor device can be flexibly configured, which make energy storage system performance greatly improved. This template explains and demonstrates how to prepare your camera-ready paper for Trans Tech Publications. The best is to read these instructions and follow the outline of this text.

Design of an Average-Current-Mode Noninverting Buck–Boost DC–DC Converter With Reduced Switching and Conduction Losses

With the rapid growth of battery-powered portable electronics, an efficient power management solution is necessary for extending battery life. Generally, basic switching regulators, such as buck and boost converters, may not be capable of using the entire battery output voltage range (e.g., 2.5-4.7 V for Li-ion batteries) to provide a fixed output voltage (e.g., 3.3 V). In this paper, an average-current-mode noninverting buck-boost dc-dc converter is proposed. It is not only able to use the full output voltage range of a Li-ion battery, but it also features high power efficiency and excellent noise immunity. The die area of this chip is 2.14 × 1.92 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , fabricated by using TSMC 0.35 μm 2P4M 3.3 V/5 V mixed-signal polycide process. The input voltage of the converter may range from 2.3 to 5 V with its output voltage set to 3.3 V, and its switching frequency is 500 kHz. Moreover, it can provide up to 400-mA load current, and the maximal measured efficiency is 92.01%.

The Modeling and Simulation of Super-Capacitor in Diesel Engine Starting Process

Diesel engine; Super-capacitor; Starter system; Modeling; Simulation Abstract. In order to improve the start-up performance of the diesel engine and the working conditions of batteries, make efficient use of the high instantaneous discharge power characteristics of the super-capacitor as a diesel engine start-up auxiliary power. Taking the YC6J180 types of Yuchai diesel engine as illustration, diesel engine starting process was modeled and simulated by Matlab/Simulink software, and compared with the simulation model of diesel engine starting system added the super-capacitor. The simulation results show that the diesel engine starter system added the super-capacitor as the auxiliary power, the starting performance is improved significantly, meanwhile improve the battery state, and extend its service life.

High power characterization of (Na0.5K0.5)NbO3 based lead-free piezoelectric ceramics

Though there is a lot of research related with lead-free piezoelectric materials, there are quite few research on high power characteristics of the lead-free piezoelectric materials. Especially under equilibrium conditions (continuous drive), high power characteristics in resonance and anti-resonance regions still remain unrevealed. This study investigates the high power characteristics of a sodium-potassium-niobate (NKN) based piezoelectric ceramic compared to hard lead-zirconate-titanate (PZT) under equilibrium conditions. High power characteristics were investigated with our novel high power piezoelectric characterization system (HiPoCS). (Na0.5K0.5)(Nb0.97Sb0.03)O3 was prepared with 1.5% mol CuO addition with the mixed–oxides method. Disk-shaped samples were sintered with the conventional sintering methods. The mechanical quality factor (Qm) at resonance (QA) did not possess degradation with the increasing vibration velocity (vrms). Accordingly, it remained constant up to 0.4m/s, which corresponds to the maximum vibration velocity (vrms measured with 20°C increase of the temperature on the nodal point). This behavior is superior when compared to hard-PZTs with their sharp decrease in QA with the increasing vibration velocity. At anti-resonance, the high power behavior trend was similar to that of at resonance. The mechanical quality factor at anti-resonance (QB) also remained constant up to the maximum vibration velocity (vmax=0.4m/s). Moreover, QA and QB were in the same order up to vmax. This trend is also distinctly different than hard-PZTs and needs to be further investigated. In conclusion, NKN ceramics are capable of possessing good high power behavior at both resonance and anti-resonance modes.