Applied Mechanics and Materials Vol. 707

Abstract: The aim of this paper is to propose a new multi-sensor target recognition method based on VIKOR method. Multi-sensor target recognition is an important part of information fusion. The multi-sensor target recognition problem contains many factors, and thus it is actually a multi-attribute decision problem. The new multi-sensor target recognition method combines the VIKOR method with G1 method. G1 method is an objectively determining weights method, and it does not need to test the consistency of judgment matrix, thus it is better than AHP. A practical example is studied to demonstrate the effectiveness and feasibility of the proposed method.

Abstract: A control strategy and implement method for the no-load cutting-in of double-fed induction generator in power system are introduced. The paper analyze the basal principle of DFIG under no-load condition, and build the correspondent mathematical model. Then according to the model, the paper propose a control strategy on the basis of magnetic flux linkage vector orientation control. Using simulation software set up a simulation model. The result of simulation showed that: the no-load grid connection control strategy can effectively keep the stator voltage track the time-varing grid voltage. At the interconnection instant, the impulse current is almost zero, thus the soft cutting-in of DFIG is well realized.

Abstract: As the number of doubly fed induction generator (DFIG)- based wind-turbine systems continues to increase, wind turbines are required to provide Low Voltage Ride-Through (LVRT) capability, especially under the condition of grid voltage dips. This paper, depending on the operating characteristics of doubly-fed induction generator during grid faults ,deals with a protection and control strategy on rotor-side converter (RSC) to enhance the low voltage ride through capability of a wind turbine driven doubly fed induction generator (DFIG). The simulation and experiment studies demonstrate the correctness of the developed model and the effectiveness of the control strategy for DFIG-based wind-turbine systems under such adverse grid conditions.

Abstract: Based on estimation of signal parameters via singular value decomposition (SVD) filtering technique and Multiple Signal Classification (MUSIC) combined with extended Prony algorithm, a new method for induction motor’s broken rotor bar detection is proposed. Experiments show that the method is effective in applying to detect the fault of motor’s induction with the situation of interference noise and load fluctuations. And it is more practical in line detection because the algorithm is relatively simple and the running time is short.

Abstract: Based on the phase time definition,we study theoretically the transmission coefficients and the spin-tunneling time in parabolic-well magnetic tunneling junction with a tunnel barrier in the presence of Rashba spin-orbit interaction. The significant quantum size, quantum coherence, and Rashba spin-orbit interaction are considered simultaneously. It is found that the tunneling time strongly depends on the spin orientation of tunneling electrons. We also find that as the length of the semiconductor increases, the spin tunneling time shows curved increase. It exhibits useful instructions for the design of spin electronic devices.

Abstract: Rotor inter-turn short-circuit is a common fault in generator and it is a research hotspot to identify the fault at its early stage. Considering the disadvantage of circuit analytical method, this paper establishes a 2D transient finite element electromagnetic-circuit coupling model, and calculates the magnetic field at normal and fault situations through the powerful post-processing function of ANSOFT, then magnetic flux density cloud pictures and air-gap magnetic flux density curves of different operating conditions are got. Using MATLAB to analyze and deal with the air-gap flux density cures, we can get the differences of faults in different levels and different positions, which provide a basis for further study of rotor inter-turn short-circuit fault.

Abstract: In view of the field work environment of artificial larch forest in the mountains, The forest seed Loam cutting and collecting machine is designed for adapting to the mountain woodland inter-row work environment. The machine finishes completing the soil cutting and collecting through a homework, meeting the job requirements, and the operation is simple、the ability is strong, it can meet the need of mountain forest farm.

Abstract: The principles-related knowledge of boiler is mainly applied to analyze the relationships between boiler efficiency and excess air coefficient and the main parameters, and also the method of optimizing operation of the boiler is proposed.Key words: image analysis method; principal component analysis; boiler efficiency; optimizing operation

Abstract: The objectives of this work are to evaluate the performance and analyze the factors which could be having an influence of vibration subsoiler in cultivation, and to envisage and design the measurement and control system based on the existing research in the soil bin test platform. The system consisted of three distinct subsystem: a subsystem for controlling subsoiler based on a AC variable frequency motor at oscillating frequency of 0-60Hz and amplitude of 10mm, a ‘complicated box’ subsystem for getting data from various sensors which were distributed in each part of the system under test and an analysis system with a mobile-friendly interface on PC base on labview software. Finally, the kinematic and dynamic analysis of the subsoiler were studied on the basis of single-factor and multi-factor experiment, and experiment results showed that the frequency factor suggested a coupling of the influence of the soil, the subsoiler and the operating conditions.

Abstract: In order to satisfy different field requirement of product transmission during the process of its making and storing, this paper offered a brand new modular 3-D ribbon conveyer. Compared with traditional ribbon conveyer, it has some excellent properties like modular design, adjustable transmission path, and independent driving. As a result, it can change its transmission path in 3-D space and convey product to the prescribed location.