Applied Mechanics and Materials Vols. 380-384

Abstract: The research of thermal resistance, an important parameter for the thermal characterization of Power MOSFET device, is gaining increasing importance. Structure function, a novel and popular method, can be used to analyse the thermal characterization of Power MOSFET. In this paper, Wiener filter, a frequency-domain method of performing deconvolution that produces the structure function, is proposed. This method is applied to a Power MOSFET device in a TO-39 package. The thermal resistance of this Power MOSFET device was analysed from the structure function based on Wiener filter method.

Abstract: Electric vehicle is an important part of the smart grid. However, when electric vehicle charging station which is with massive application of the power electronic equipments connects to the grid, it will make a lot of power quality problems, especially the harmonic problems. This paper analyses the mechanism of harmonic generation caused by high-frequency charger, proposes to use APF to deal with power quality problems , and verifies the viability and effectiveness.

Abstract: Capacitive coupling connector subjects to excessive inter-symbol interference with the increasing of signal transmission rate. To solve this problem, a driver-side equalization scheme is proposed, and the calculation method of precise equalization ratio for this scheme is also given. The equalization scheme is implemented through select appropriate equalization ratio to increase high frequency components of signal and reduce the low frequency components of signal at the driver-side at the drive-side. It can reduce the inter-symbol interference and improve pulse magnitude effectively. Simulation and calculation results show that the equalization scheme can increase the pulse amplitude in receiver-side, eliminate inter-symbol interference and improve signal transmission rate greatly.

Abstract: Building enough charging stations is the only way to let new energy vehicles come into our daily life. While, the cost of building a charging station is very expensive. Therefore, spatial optimal location of charging stations has to be dealt with. The main purpose of this paper is to investigate the spatial optimal location of charging stations using Gaussian Mixture Model clustering and charging requirement spots are taken as the clustering benchmark. The clustering procedure of charging station spatial optimal location is programmed using m-language. Finally, simulation results show the validity of proposed method.

Abstract: Timing system is widely used in plenty of fields. This paper introduces a method to use PLD programmable devices to design a timing system which has been optimized and then become especially suitable for humans listening habit. The design circuits and simulation waveforms are shown in the paper. The simulation results show that the design is practical and easier to implement.

Abstract: In the phased array imaging system, in order to get better images,the lateral resolution need to be improved and the grating lobes need to be eliminated. Restrainning the width of the main lobe is a way to improve the lateral resolution of the system. This article designed the non-periodic distribution of elements to decrease the width of main lobe of the transducer using sparse matrix methods. In this way, we can improve the lateral resolution, resolve the problem of high-density of elements in phased array element, eliminate the impact of the gate lobe, lowerring the effects of radiation in the neighboring elements, save costs and overcome the difficulty in production of elements.

Abstract: With the rapid development of electronic technology, the integrations of chips and modules become much more complex. Various types of communication equipment with more functions which make the heat of the device to increasingly become a problem. High temperatures may seriously affect the validity and reliability of electronic equipment and components. In order to dissipate the heat to the ultimate sink, thermal design need to design low thermal resistance paths both inside the electronic device and between the electronic device and the external environment. Industrial Ethernet switch runs in harsh environment, and the reliability, stability, security, environmental adaptability requirements higher than that of commercial Ethernet switches, these require a higher standard thermal design.

Abstract: As IEC61850 has become the general international standard of substation communication, protections and the other secondary devices have new characteristics of digitization and network. The input signal is no longer the traditional analog alternating current component and the protection trip switch, SMV Message and Goose Message instead. The network performance is more and more important and normal relay protection test device is no longer suitable for digital protections. This paper has analyzed the transmission methods of the SMV message and GOOSE message, developed the digital protection test platform based on RTDS and put forward a digital protection test interface design based on FPGA.

Abstract: NAND Flash-based SSD has gained prevalence in enterprise and embedded system as storage device because its high I/O performance, low-power consumption, and Anti-vibration characteristics. RAID consisting of SSD can achieve higher performance. However, it brings new problems such as parity disks suffering from premature aging, data disk aging simultaneously. This paper based on the variation of SSDs reliability, design a new RAID-5 architecture with dynamic stripe length. It can effectively reduce the disk space overhead and improve the safety performance of the RAID.

Abstract: Resolving the contradiction between trees and power transmission lines in time is an important work to ensure the safety of transmission line operation. While it is difficult to decide the trees trimmed time during the transmission line operation and maintenance, the development of the management information system for protecting distance between transmission lines and trees, which is used to auxiliary predict the date of pruning, is a way to solve the problem. Collected attribute data of transmission lines and trees, the corresponding database is established. Therefore, Visual Basic 6.0 is adopted to develop the software system. Based on the spatial coordinates of line towers, conductors, and tree crown, the three-dimensional mathematical model is established to calculate the spatial distance between the conductor and tree crown. According to the mathematical model, the trees growth rate of year, month and day, respectively, and the protecting distance standard between conductor and tree crown, the system could calculate the actual spatial distance between conductor and tree crown, and auxiliary predict the pruning date.