Applied Mechanics and Materials Vols. 325-326

Abstract: There are fading and noise in MIMO two-way relaying system. A novel transmission scheme was proposed. The scheme performs equivalent to a 2×2 V-BLAST MIMO(Multiple-Input Multiple-Output) and a two 2×1 AlAMOUTI MISO(Multiple-Input Single-Output) in multiple-access phase and broadcast phase respectively. Network coding and minimum mean square error detection are employed at the relay. Binary phase shift keying and 8 phase shift keying modulation is used. The performance is analyzed under the assumption of a symmetric relay channel model. Simulation results show that the proposed transmission scheme can facilitate more reliable transmission.

Abstract: While designing the drive train of a Series Hybrid Vehicle fuel efficient vehicle for Shell Eco Marathon Asia 2010, The most important issue was the coupling of Engine and Alternator. The major problem faced while doing so is the compatibility check of alternator with the engine as most locally available alternators were not capable enough to provide 48V at rated power of the engine required for operation of hub motors used in the drive train. In order to overcome this problem, it was decided that Magic Pie DC Brushless Hub motors may be used as improvised alternators, as the regenerative abilities of these motors provide an excellent platform to use it as an alternator and are fairly efficient as well. Many small mechanical modifications and mathematical calculations were done in order to achieve this goal.

Abstract: The article presents the results of conducting experimental research on factors influencing the positioning precision/error of linear electrohydraulic servomechanisms. Based on the mathematical model and preliminary experimental research conducted there have been identified factors that influence the positioning accuracy, and have been proposed some measures to control it in normal limits. The experimental results obtained highlight interesting aspects from the scientific point of view; they can be used to optimize the positioning precision of linear electrohydraulic servomechanisms.

Abstract: A langevin-type ultrasonic motor works using two orthogonal bending vibration modes. However, due to the influence of machining error, heterogeneous materials, especially the screw stress unevenness along the circumferential direction, the modal frequencies of two vibration modes are different, which will affect motor performance. Earlier research only deals with the axial position to chamfer to reduce the frequency difference, and think vibration direction consistent with excitation direction. While experimental results show that these two directions are generally different. By using Finite Element Method (FEM), a square-base stator is simulated, and the relationship is obtained qualitatively between the extreme value amplitude point and the extreme value bending moment of inertia of the stator. At last, an experimental method is presented to determine the maximum vibration amplitude position of a cylinder ultrasonic motor when the excitation angle changes in the range (-90,90].

Abstract: Equiped with an electronic differential function in double wheel or four wheel electric vehicle drive, it must be driven by motor torque control precisely . Due to the nonlinear characteristics of the motor when the wheels switched reluctance motor drive, it is difficult to ensure motor torque and phase current relationship by the theoretical approach. This paper puts forward the experimental methods to get the different speed motor torque and given the relationship between the current , so as to make table, according to the rotation of the motor speed and torque requirements, the accurate switched reluctance motor torque control through given the current value in the future of the electric vehicle.

Abstract: This article is based on finite element theory and use ANSYS simulation software to establish electric field calculation model of converter transformer for a ±800kV and make electric field calculation and analysis for valve winding. Converter transformer valve winding contour distribution of electric field have completed in the AC, DC and polarity reversal voltage.

Abstract: The paper presents the theoretical results of extensive research on the dynamic behavior of linear hydraulic motors, carried out in INOE 2000-IHP, in the framework of the NUCLEU Programmer. The research has been conducted both theoretically and experimentally, but, in this paper, is presented only the theoretical research. Theoretical research has taken place with the modern means of mathematical modeling and computer numerical simulation. The article presents some theoretical interested results obtained in the research, results that are of real scientific interest, but, also, with practical value through their use in the design of fluid power components and equipments.

Abstract: In this paper, common mode (CM) conducted perturbations are predicted and compared with experiments in a full-bridge transformer-isolated buck converter system, thanks to a complex approach based on experimental measurements and on the modeling of the complete equivalent circuit. Its different part are considered and represented by a circuit of lumped parameters. Simulation and experiment of CM emission in the conducted frequency range (150 kHz-30 MHz) are compared. It is shown that the CM emission in the system can be calculated by the proposed model, and experiment has successfully confirmed this approach.

Abstract: In order to design the section size of a rectangular waveguide, this paper gives a new method to design the section size of a rectangular waveguide and the result obtained has important reference value for the design and research of sectional dimension. Based on the wave equation of electromagnetic wave, graphic method is employed to determine the transmission condition of fundamental mode in rectangular waveguide. We analyzed the power capacity and attenuation characteristics when the rectangular waveguide transmits with single-mode, and finally obtain the guidance condition for the power capacity reaches the maximum and the attenuation reaches the minimum in the rectangular waveguide.

Abstract: Based on the analysis on shortcomings of controlling strategies of direct power on the traditional 3-phase Boost-type PWM Rectifier through space vectors, a new controlling strategy is proposed in this paper. With this new strategy, the space vector is divided into 12 basic space vectors to form a new switching table. The instantaneous power controlling technology is realized through the control of instantaneous active power and reactive power by choosing the best switching state of PWM Rectifier. This new controlling strategy can put the input side unit power into operation, improve the efficiency of power and reduce harmonics of the input current. The effectiveness and feasibility of this controlling strategy have been justified through the simulation and experiment.