Applied Mechanics and Materials Vols. 644-650

Abstract: For quantitative analysis of impact of grounding capacitance on the traction power supply system, in this paper, two wires system as an example with the mirror image method concluded the calculation formula of two wires system to ground capacitance and partial capacitance. At last, the influence of grounding capacitance on the traction power supply system is given quantitatively to provide the more accurate basis for engineering calculation.

Abstract: Service restoration which is an important part in smart distribution network has become more important in improving the reliability to customers and reducing the interruption loss. The mathematical model including objective functions and electrical constraints are overviewed in the paper. Three algorithms based on heuristic search, artificial intelligence and combinational method are elaborated separately. Finally, the problems needing to solve in future are discussed combining with the research status and the recent advance in distribution network.

Abstract: To solve the wide range of the output voltage, difficult storage and not unified interface of solar cell, a novel solar charging system was proposed. The system consists of the solar panel, the voltage regulator circuit, the battery charge management circuit, the lithium battery, the booster circuit and the USB output circuit. The voltage regulator circuit can convert the output voltage of solar panel into 5V. By means of the charge management circuit, the energy is stored in the lithium battery, and it can be provided to the load via the booster circuit and USB interface, which can achieve the goal of the conversion, storage and utilization from solar to electrical energy. Under the condition of effective illumination between 10:00 and 16:00, the solar charging system was tested for 7 days. Experimental results show that the output voltage always maintained at 5V during the test. The output voltage of lithium battery reaches to 4.2V after four hours, and the output voltage of USB port always stabilizes at about 5V.

Abstract: A multi tone modulation system design and development with a low-cost and high performance was developed, taking LabVIEW as the software development platform and the computer sound card as the hardware platform. The system is capable of audio signal acquisition, multi tone modulation, demodulation, waveform and spectrum analysis, and other functions. Actual application shows that the system is not only high accuracy, and reliable, stable performance, easy to operate and extensions. The signal collection technology based on the sound card and the combination of virtual instrument has a broad application prospect in engineering survey and practical teaching.

Abstract: Aiming at the loss of image boundary information and the blurred image details in the classical median filtering algorithm, the improved median filtering algorithm based on FPGA (Field Programmable Gate Array) is proposed. In the improved median filtering algorithm, the borders mirroring and threshold comparing are adopted, and the loss of the image boundary information is lowed and the detailed information of image is preserved. The improved median filtering algorithm based on FPGA consists of the filter template generating module, the median grayscale computing module and threshold comparing module. The experimental results show that that the NMSE (normalized mean square errors) of the image filtered with the improved median filtering algorithm is lowed by 25.6%, and the operating efficiency is improved by 16% comparing with the classical median filtering algorithm.

Abstract: Serial concatenated convolutional codes (SCCC) have gained a great interest in recent years for outperforming PCCC at high SNR and lower error floor. In this paper, the BER performance of SCCC based on different decoding algorithm such as Log-MAP algorithm, Max-Log-MAP algorithm and improved Max-Log-MAP algorithm are investigated. In order to achieve a flexible high throughput, low complexity and multi-rate decoding process, some improved methods are proposed.

Abstract: The basic design concept and the necessities of virtual power plant (VPP) are introduced after analyzing the future conditions of global energy demand. According to the differences in functions, VPP is divided into two roles, the commercial virtual power plant and the technical virtual power plant. After comparing their characteristics, related connections between them are proposed. Power quality control technologies and auxiliary services provided by VPP are discussed in detail based on current domestic and international research situation. Finally three scheduling control modes, the centralized mode, the decentralized mode and the distributed mode are compared. Correspondingly, the result that distributed control mode is more suitable for optimal scheduling control of VPP is pointed out.

Abstract: In coordinated evaluation of electricity ecosystem, it’s should not simply on the basis of the value of information transmitted by index, but also make a comprehensive analysis of knowledge and experience of experts and policymakers. In this paper, the actual situation of Guangxi power grid as an example, the electricity ecosystem coordinated development optimization based on the constraints of resources and environment is carried out. And explore the relationship among the electric power industry, regional environment and economy. The comprehensive evaluation method based on entropy weight and AHP is suggested, which solves the casualness and subjectivity problem about weight decision in traditional comprehensive evaluation method, in order to improve the accuracy and credibility of evaluation results, and put forward new ideas for the coordination of protection of Guangxi regional power industry and environment development, in order to achieve the harmonious development among economy, environment, power.

Abstract: Due to various reasons, the power supply system of LED light sources exist many problems to be solved and optimization. This paper designs a set of small photovoltaic system and equipped with new energy device, provide enough clean energy to LED plant lighting system, reduce electricity costs. We present an improved three point tracing algorithm to trace the maximum power point of solar panel, to maximize the photovoltaic conversion rate. Using double quadrant half bridge current reversible DC/DC converter circuit to realize the automatic charging and discharging of the energy storage module.

Abstract: Sneak Circuit Analysis (SCA) is a technical means. It can solve practical problems in engineering, provide security of the system. To solve the problems of traversal qualitative for sneak circuit analysis, the importance of switch nodes in circuit network was proposed based on the quantitative analysis model of sneak circuit. Quantitative models for sneak circuit analysis were established and the circuit network's composition method was determined based on circuit topologies and line information. Because of the limitation of full traversal method, polycondensation degree was applied to evaluate node importance in sneak circuit analysis. The importance of switch nodes was recognized by taking degree of polycondensation as an evaluation indicator. Key nodes take core analysis algorithms and the other nodes use adding analysis algorithms. To illustrate the effectiveness of this method, emulation of switches’ state was taken as the example of sneak circuit compared with traditional methods of identifying node importance such as node degree and betweenness.