Advanced Materials Research Vol. 749

Abstract: This paper introduces a control system based on ARM and WINCE for optical eccentric detector. The system adopts S3C6410 based on ARM11 architecture as the core chip controls the four-phase stepping motor to drive the rotation of mirror being tested, captured by the image sensor OV9650.It can capture the brightest point in each image, and fits multiple points from many images by least square circle fitting to get the optical eccentric value. Test results show that the system works well and gives stable data, with good real-time performance.

Abstract: The effect of the mechanical heterogeneity on the global and local tensile properties of laser-arc hybrid welded joints in industrial pure aluminum has been investigated. Digital image correlation method has been used during tensile test for mapping the strain distribution and to determine the local stress-strain curves of FZ and HAZ. The tensile properties of the various regions are very heterogeneous and HAZ is the weakest region because of the strain localizes during tensile test. Finite element technique was used to model the global response of welded joint based on local constitutive properties which could be determined from DIC results.

Abstract: Modern power grid is an important part of national energy strategy. Smart grid is one of the directions to modernize the electricity grid. Smart grid is the intelligent of power system, It is also known as the grid 2.0.It is based on integrated, high-speed bidirectional communication network ,It use the advanced sensor and measuring technology, use advanced equipment and control method to realize the application of the power grid reliability, safety, economic, efficient, environmental friendly and safety. High speed, bidirectional, real-time, and integrated communication system is the foundation and key point when monitoring and control smart grid. So How to improve the communication technology is very important.

Abstract: At present years, the photovoltaic industry has a rapid development. The research of related technologies also has made tremendous progress. The photovoltaic power generation system includes the solar array, controller, batteries, inverter, electricity load, etc. In this paper, combining with domestic and foreign research status quo, respectively summarizes four aspects of photovoltaic system technology, the maximum power point tracking, DC converter, inverter and islanding detection.

Abstract: With the wide application of power electronic devices, especially the use of non-linear device, a large number of harmonics and reactive current injected into the grid, which will cause power grid pollution, and the power quality problems have become increasingly serious .Active Power Filter (APF) is an important device for the power system harmonics and reactive power compensating. The real-time control and accuracy is a key to achieving effective compensation. Several suitable for active power filters basic principle of the compensation current control strategy is introduced in this paper, the paper carries on the contrast analysis, and points out the advantages and disadvantages of each, The development of the control strategy of the active filter can achieve a better performance and a wider range of application.

Abstract: This paper describes the connotation and characteristics of the smart grid, detailed key technologies and features of the smart grid. Finally, discusses the opportunities and challenges facing in China in the development of smart grid.

Abstract: Traditional central power supply and distributed generation have the advantages and limitations themselves. Micro grid technology can integrate the advantages of distributed generation and that makes for large scale new energy and renewable energy power generation system connected to the grid. First, the micro grid research background and significance are introduced in detail, then the current research situations of micro-grid at home and abroad are represented, in the end, the key problems and development prospect of micro grid are discussed emphatically.

Abstract: The problem of more and more serious reactive power and harmonic pollution to power systems is getting more and more serious, which has caused great concern. One of the key points for proper implementation of an APF is to use a reliable method for current/ voltage reference generation. Consequently, how to detect harmonic quickly and accurately becomes a crucial problem. From the perspective of historical development of detection methods, it experienced a course from frequency domain and time domain and neural network to Adaptive parameter identification. Several methods of measuring harmonic, such as wavelet/ S transform, Fourier transform are introduced and compared in this paper.

Abstract: Due to the complexity of wind power system, it would make chaotic phenomenon which had existed in power system, a typical nonlinear system,receive more attentions. With its own characteristics, causes and hazards of chaos, it is determined to be valuable in research. At present, the wind power system chaotic phenomenon has become another popular direction in the study of wind power system. Its significance and prospect can be very large.

Abstract: With the rapid development of Chinese economy and the speeding up urbanization, urban rail transit has entered a rapid development period, which results in more and more energy consumption. Meanwhile affected by energy source and environment factors, the state has implemented energy-saving emission reduction strategies in various fields, so energy efficient management for urban rail transit becomes more important. Based on the analysis of energy consumption problems in urban rail transit, the paper designs urban rail transit energy efficiency management system from the aspects of overall architecture, service architecture and application function, and provides technical support for the realization of the software system.