Papers by Author: You Hua Wang

Abstract: 270V high voltage DC power supply system with grid of light weight, uninterrupted power supply and a two power density higher characteristic, in recent years become a hot research topic in domestic and international air supply system.[ To ensure the high voltage DC bus power quality, for the safe operation of the aircraft is very important. Single phase aeronautical static inverter as a typical aircraft power system load, the input current ripple of the serious pollution of the high voltage DC power supply. Therefore, the harmonic pollution problem of how to control the high voltage DC power supply system has been increasingly concerned aviation power researchers.

Abstract: Solar energy is the inexhaustible,enewable Energy. The solar cell is the solar light energy into electricity. The unique advantages of solar cell. Potential, more than wind, hydro, geothermal energy, nuclear energy and other resources, is expected to become the main pillar of power supply in the future. This paper studies that the main parameters of monocrystalline crystal silicon solar battery: the junction depth and superficial concentrations influence on electrical characteristics of monocrystalline silicon solar battery. The result shows that for maximum efficiency, it is bound to get the largest possible open circuit voltage, short circuit current and fill factor of the product, therefore, it is necessary to control these two parameters, the junction depth and doping parameters. If the junction depth is constant, with the increased superficial doping concentration of monocrystalline silicon solar battery, the photoelectric conversion efficiency of the battery increases slowly at first and then rapidly decreases, and the deeper the junction depth is, the more obvious trend of the photoelectric conversion efficiency is.

Abstract: Based on the platform of laser-triggered surface flashover in pulsed voltage, experiment of laser-triggered surface flashover is carried out in air and vacuum condition with pulsed voltage. A single/double harmonic, with wavelength of 1064/532 nm, Q-switched Nd:YAG laser is applied to trigger the surface flashover. The test system consists of flat electrodes and columned insulator. The material of electrode is copper and the material of insulator is Al₂O₃. Laser pulse’s wavelengths are 532nm and 1064nm, and laser is focused with rectangle. The results of experiment show that flashover delay time and jitter time decrease with increase of pulsed voltage or laser energy density, the delay time of 1064nm laser trigger is larger than that of 532nm laser trigger, and the delay time and jitter time in vacuum condition are less than the delay time and jitter time in air condition.

Abstract: With the advent of power electronic technology, the excitation conditions applied to transformers, motors, etc. could be very atypical. DC bias excitation is an undesired working condition of AC power transformers, the asymmetrical saturation of the transformer core, the heavy noise, the serious vibration, and the local loss concentration can all potentially occurred in dc-biased transformers. The effect of the exciting current under different dc-biased magnetization on eddy-current loss in copper plate based on a reduced engineering-oriented benchmark model (TEAM Problem 21) is investigated. Experiment scheme for dc biasing is presented and the distribution of the eddy current loss under different dc-biased excitation conditions was studied in detail. The engineering applicability of three dimensional eddy current analysis methods for dc-biased magnetization field computation and the practical loss modeling are examined, which has been demonstrated via the numerical modeling results and the measured data.

Abstract: In order to improve the magnetization effect of permanent magnet motor, it is requires accurate and efficient magnetization circuit except that we choose the permanent magnet with high coercive force. The method of pulse discharging for permanent magnet motor magnetization is simple, fast speed and the magnetization effect is good. The parameter selection of pulse circuits influences the magnetization effect directly. The pulse circuit parameters were simulated through parameter scanning method, using Pspice simulation software. Appropriate circuit parameters were obtained through comparing the pulse discharge current waveform, which will ensure the best magnetization effect of the permanent magnetic motor.

Abstract: Dual laminated core models for determining exciting power (or/and specific total iron loss) and over saturation characteristics occurred at joints and silicon steel sheet was proposed and prototyped. Calculation method of exciting power at joints of transformer was presented. The saturation characteristics of laminated silicon steel sheets was obtained and analyzed. The model also can be used to investigate the relevant electromagnetic behavior of laminated core in detail.