Influence of dc Component during Inadvertent Operation of the High Voltage Generator Circuit Breaker during Mis-Synchronization

This paper analyses the synchronization problem of a generator onto power system without satisfying synchronization condition. The main focus of the paper is on the impact of the dc component of the current in the high voltage circuit breaker during its close-open operating cycle. Using real time measurements of currents/voltages and angles during the close-opening cycle of high voltage generator circuit breaker and the impact of the dc component of current in context of interrupting large magnitude of current from the circuit breaker. In addition, the paper describes a study case model and the results of simulations performed using the software EMTP-ATP of an actual incident that occurred during the inadvertent synchronization of a large 339 MW, 24 kV generator to the grid.

Design of High-voltage Electrostatic Generator Based on STM32

This paper introduced a high-precision high-voltage electrostatic generator which utilized STM32F103 as the main controller.The hardware and software design of the system were detailed.The full use of ample on-chip resources of STM32F103,such as ADC and the PWM output of timer,contributed to the small size and low cost of the system.The 16-bit PWM signals,generated by the timer on chip,served to adjust the output voltage accurately.The touch screen was responsible for the setting and display of output voltage,and the friendly human-computer interaction was built.Experimental results indicated that this high-voltage static generator was of high precision and great practicability for application.

Computer Controlled High Precise, High Voltage Pules Generator

High precise, high voltage pulse generator made up of high-power IGBT and pulse transformers controlled by a computer are described. A simple main circuit topology employed in this pulse generator can reduce the cost meanwhile it still meets special requirements for pulsed electric fields (PEFs) in food process. The pulse generator utilizes a complex programmable logic device (CPLD) to generate trigger signals. Pulse-frequency, pulse-width and pulse-number are controlled via RS232 bus by a computer. The high voltage pulse generator well suits to the application for fluid food non-thermal effect in pulsed electric fields, for it can increase and decrease by the step length 1.

Plasma Simulation of Dielectric-lined Multiwave Cerenkov Generators Producing High Power Millimeter Waves

This paper presents the concept of a Dielectric-lined Multiwave Cerenkov Generator producing high power millimeter waves, which has been investigated with a two and onehalf dimensional electromagnetic relativistic Particle-in-Cell (PIC) plasma simulation code. Themodified device can operate in a lower diode-voltage regime with much higher radiation efficiencyand slight downshift of operation frequency. There exist the optima for the permittivity of thedielectric liner and for the magnitude of the guiding magnetic field. The required intensity of theguiding field is reduced by the introduction of the liner. The enhanced propagation of the electronbeam is studied in the presence of the liner.

Comparing High-resistance Grounding Method with Resonance Grounding Method for Large Generators

For large generators, the problem of high-resistance grounding method and the advantages of resonance, grounding method are discussed in detail, and an overall comparison is given in this paper. It is recommended that the latter should be adopted so as to increase the operation reliability of large generators and power systems.

Effects of Vortex Generator Jet on Corner Separation/Stall in High-Turning Compressor Cascade

The effects of the vortex generator jet(VGJ)attached at the endwall on the corner separation/stall control are investigated by numerical simulation in a high-turning linear compressor cascade. The results show that the corner separation could be reduced significantly, which results in a wider operation range as well as a more uniform exit flow angle and total pressure profile. At the near-stall operation point, the maximum relative reduction of the total pressure loss is up to 32.5%,, whereas the jet mass ratio is less than 0.4%,. Based on the analysis of the detailed flow structure, three principal effects of the VGJ on the endwall cross flow and corner separation are identified. One is to increase the tangential velocity component opposite to cross flow, thus inhibiting the endwall secondary flow near the jet exit. The second is to suppress the pitchwise extension of the passage vortex as an air fence. The third is to sweep the low energy fluids towards the mainstream on the up-washed side and to transport the mainstream fluids to the endwall to reenergize the boundary layer on the down-washed side.

Fully Integrated High-Voltage Generators with Optimized Power Efficiency

This paper describes how the power efficiency of fully integrated Dickson charge pumps in high- voltage IC technologies can be improved considerably by implementing charge recycling techniques, by replacing the normal PN junction diodes by pulse-driven active diodes, and by choosing an appropriate advanced smart power IC technology. A detailed analysis reveals that the combination of these 3 methods more than doubles the power efficiency compared to traditional Dickson charge pump designs.

Two-Capacitor Electrostatic Microgenerators

All modes of operation of a two-capacitor generator based on overflow of the charge accumulated in capacitors through the load resistance between two capacitors with antiphase modulated capacitances by means of in-plane or out-of-plane shift of the electrode plates under action of a mechanical force are analyzed paying the especial attention to fabrication of the generators with small sizes. Numerical solutions for all the modes are obtained, and they are found to be universal. Analytical estimates of the maximum power of the generator as a function of the capacitances modulation factor are derived. Experimental investigations of a two-capacitor rotational electric generator show that its characteristics are consistent with the analysis performed and that this analysis can be used to describe all specific features of operation of particular generators. Applications of the devices in micro-design for feeding the remote sensors are discussed.

Generating Proton Beams Exceeding 10 MeV Using High Contrast 60TW Laser

A prototype of a laser driven proton accelerator is built at Peking University. Protons exceeding IOMeV are accelerated from micrometer-thick aluminum targets irradiated by tightly focused laser pulse with 1.8 J energy and 30fs duration. The beam energy spectrum and charge distribution are measured by a Thomson parabola spectrometer and radiochromic fihn stacks. The sensitivity of proton cut-off energy to the focusing of the laser beam, the pulse duration, and the foil thickness are systematically investigated in the experiments. Stable proton beams have been produced with an optimized parameter set, providing a cornerstone for the future applications of laser accelerated protons.

Effect of laser intensity on quantum trajectories in the macroscopic high-order harmonic generation

We macroscopically investigate the effect of the laser intensity and gas density on quantum trajectories in the highorder harmonic generation of Ne atoms irradiated by few-cycle, 800-nm laser pulses. The time–frequency profile of the harmonics shows that the long quantum trajectory is dominant at both lower and higher gas densities for a low laser intensity. At high laser intensities, the long quantum trajectory plays an important role for lower gas densities, while the short quantum trajectory is dominant at higher gas densities. An analysis of the phase mismatch for high-order harmonic generation shows that the primary emission of the quantum trajectories is determined by dynamic changes in the laser electric field during the propagation process.

Automatic Generation of the Planning Tunnel High Speed Craft Hull Form

一艘轮船到的几何模型的创造决定特征静水力学并且水动力学，并且也在轮船设计过程为结构的设计和设备安排是那么重要的。计划隧道高度速度手艺是在的手艺之一，到他们的最高的速度的成就是更重要的。有隧道的使用的这些手艺有飞行器水动力学的性质减少抵抗，好经得起海上风浪的行为，减少撞击并且避免 porpoising。因为隧道的存在，这些手艺的壳形式产生更复杂、困难。在这份报纸，它试图基于几何学创造指南并且与最少的控制和壳形式调整参数的一个条目提供一个方法，到自动地产生计划的壳形式隧道手艺。起初，数学模型的方程被描述并且随后，基于现在的方法产生的三个不同模型被比较并且分析。显然，产生模型在设计的早阶段有更多的申请。

Study of simple plane wave generator with an air-metal barrier

Plane wave generators(PWGs) are used to accelerate flyer plates to high velocities with their generated plane waves,which are widely used in the test of dynamic properties of materials.The traditional PWG is composed of two explosives with different detonation velocities.It is difficult to implement the related fabrication processes and control the generated waves due to its complicated structures.A simple plane wave generator is presented in this paper,which is composed of two identical cylindrical high explosive(HE) charges and an air-metal barrier.A theoretical model was established based on two different paths of the propagation of detonation waves,based on which the size of air-metal barrier was calculated for a given charge.The corresponding numerical simulations were also carried out by AUTODYN-2D based on the calculated results,which were used to compare with the theoretical calculations.A detonation wave with a flatness of 0.039 μs within the range of 70-percent diameter of the main charge was obtained through the simulations.

Controlled teleportation of high-dimension quantumstates with generalized Bell-state measurement

In this paper a scheme for controlled teleportation of arbitrary high-dimensional unknown quantum states is proposed by using the generalized Bell-basis measurement and the generalized Hadamard transformation. As two special cases, two schemes of controlled teleportation of an unknown single-qutrit state and an unknown two-qutrit state are investigated in detail. In the first scheme, a maximally entangled three-qutrit state is used as the quantum channel, while in the second scheme, an entangled two-qutrit state and an entangled three-qutrit state are employed as the quantum channels. In these schemes, an unknown qutrit state can be teleported to either one of two receivers, but only one of them can reconstruct the qutrit state with the help of the other. Based on the case of qutrits, a scheme of controlled teleportation of an unknown qudit state is presented.

Restraint of spatial distribution in high-order harmonic generation from a model of hydrogen molecular ion

The spatial distribution in high-order harmonic generation（HHG） is theoretically investigated by using a few-cycle laser pulse from a two-dimensional model of a hydrogen molecular ion. The spatial distribution in HHG demonstrates that the harmonic spectra are sensitive to the carrier envelope phase and the duration of the laser pulse. The HHG can be restrained by a pulse with the duration of 5 fs in the region from the 90 th to 320th order. This characteristic is illustrated by the probability density of electron wave packet distribution. The electron is mainly located near the nucleus along the positive-x direction from 3.0 o.c. to 3.2 o.c., which is an important time to generate the HHG in the plateau area. We also demonstrate the time-frequency distribution in the region of the positive-and negative-x direction to explain the physical mechanism.

Overview and Analysis of PM Starter/Generator for Aircraft Electrical Power Systems

More Electrical Aircraft(MEA)which replaces the hydraulic and pneumatic power by electrical power leads to reducing emissions and fuel consumption.The MEA concept has led to a growing use of the starter/generator(S/G)system.Permanent magnet(PM)machines have been gaining interests for aircraft S/G system application over the last few years.This is mainly due to the several advantages,including high power density,high efficiency and high speed ability.The shortcoming of the PM machines is the de-­excitation problem in case of a failure,which is a main issue for the aircraft application.However,by using a PM machine with high reactance or multiphase configuration,the fault-­tolerant ability can be improved.In terms of the aircraft S/G system,this paper is going to present a comprehensive analysis of PM machines.Firstly,the state-­of-­the-­art of PM starter/generator(PMS/G)is summarized and the basic structure of PMS/G system is analyzed.Next,key technologies of the PMS/G system are summarized and analyzed.Finally,a flux weakening fault protection strategy that is used to suppress the turn-­to-­turn short circuit(SC)current is studied,simulated and verified.With the breakthrough of key technologies based on the development of high temperature electromagnetic material and high temperature power electronics,the PMS/G will be a potential candidate for aircraft S/G system including the embedded power generation system.

Extension of high-order harmonics and generation of an isolated attosecond pulse in the chirped laser field

This paper theoretically investigates the high-order harmonic generation cutoff extension using intense few-cycle linearly chirped laser pulses. It shows that the cutoff of the harmonic can be extended remarkably by optimising the chirping parameters. The time-frequency characteristics of high-order harmonics with different chirping parameters are analysed by means of wavelet transform of the dipole acceleration. It also gives out the classical three-step model pictures of electron. By superposing a properly selected range of the harmonic spectrum, it obtains an isolated 65as pulse.