Modeling Distortion Signals of Power Grid Based on Wiener-G Functionals

The uniform mathematical model of distortion signals in power grid has been setup with the theory of Wiener-G Functional. Firstly,the Matlab simulation models were established. Secondly,the Wiener kernel of power load was found based on the Gaussian white noise as input. And then the uniform mathematical model of the power grid signal was established according to the homogeneous of the same order of Wiener functional series. Finally,taking three typical distortion sources which are semiconductor rectifier,electric locomotive and electric arc furnace in power grid as examples,we have validated the model through the Matlab simulation and analyzed the simulation errors. The results show that the uniform mathematical model of distortion signals in power grid can approximation the actual model by growing the items of the series under the condition of the enough storage space and computing speed.     

一种新型太阳能跟踪系统的研究

从提高光伏发电的输出功率出发,提出了一种新型的太阳能跟踪系统.系统以DSPTMS320LF2407A为太阳能跟踪系统的核心,以混合式步进电动机为执行机构,实现水平-俯仰双轴驱动控制.同时,为了提高定位精度,采用正弦波细分驱动技术实现了混合式步进电机的精确定位.实验结果表明,系统运行稳定,与国内同类产品相比较具有较高的实用价值.     

Photothermal effects induced by laser excitation in a scanning tunneling microscope

Numerous near-field experimental methods use laser excitation inducing non-negligible thermal effects that are not taken into account. We particularly investigate the case of a scanning tunneling microscope. The analysis of the experimental results gives the thermal contribution of the probe in the measured signal when the probe is irradiated by the laser beam. The phase of the signal allows the distinction between the effects induced by the probe and the sample. We show that the experimental set-up can measure the periodic thermal expansion of the sample with the picometer resolution.