Applied Mechanics and Materials Vol. 150

Abstract: With the use of power electronic equipments and increasing nonlinear loads, the problems of quality of power supply becomes serious. Different kinds of loads need different active power filter (APF). Performance of APF depends on the design of main circuit. In this paper, the principle of APF and many kinds of structure of main circuit are presented. Multilevel, injection circuit and multiplicity are analyzed. A combined controller, the combination of PI controller and fuzzy controller, is applied to voltage control of DC side.

Abstract: According to the property of contact problem, the calculation formula of contact stress of cross-roller slewing bearing is derived under the action of eccentric axial load. The finite element model of slewing bearing is analyzed in ANSYS, and then the finite element analysis software is used to analyze the contact stress. In this way, the distribution condition of contact stress between roller and rings is obtained. By comparing the finite element analysis results with theoretical analysis results, the correctness of finite element analysis is certified, which provides a guide for the design and optimization of slewing bearing.

Abstract: Improving power factor will enhance the efficiency of power-using and the economization on energy. This article analyzes reactive power compensation in several methods, and does a detailed technical comparison. With actual situation of enterprises, some views are put forward for reactive power optimization.

Abstract: As a branch of the intelligent control, neural networks is applied in control more and more widely, the single neuron adaptive PID control algorithm is studied in this paper, and the program is written by MATLAB, the common object of single neuron adaptive PID is simulated, and the effect of single neuron adaptive PID control parameters on control effect is analyzed, experimental results show that the single neuron PID control has more obvious advantages than general PID control.

Abstract: In this paper, permanent magnetic levitation technique is studied in the research of small-sized wind-light complementary power generation system. Radial and axial permanent magnetic levitation technology has been studied, and the over design is done based on these two kinds of technologies, which make the wind power generation get breeze starting. It lays a solid foundation to achieve the breeze power generation. The overall design of the important parts of the power generation system has also been put forward in this paper.

Abstract: In the context of software reusing, component-based Software development is an emerging paradigm of development methodology. This paper studies how to apply this methodology in developing a Computerized Adaptive Test (CAT) system for college English. It describes the whole system architecture and gives some detail of Components Modeling Procedure and component repository design. The whole development process can provide valuable reference for CAT system for other disciplines.

Abstract: Artificial heart pump requires small structure, low energy consumption and certain stiffness and damping for transplanting and long time using. This paper thus designed a hybrid-type axial maglev blood pump, which not only has small size, almost no energy, and poor dynamic characteristics of permanent magnet bearing but also has low power consumption, long life and good dynamic characteristics of magnetic bearing. Based on finite element method, magnetic flux of axial magnetic bearing, radial magnetic bearing and test rig are analyzed; at the same time, the structure parameters and mechanical properties and the coupling of radial MB and axial MB are studied. The results show that: rotor displacement of axial bearing and radial bearing will affect load capacity and stiffness. The conclusions provide a scientific basis for design and optimization of blood pump

Abstract: This paper focuses on the switching power amplifier of magnetic suspension support. The principle of magnetic suspension support was described. Due to the particularity that the load of magnetic suspension support is inductive, the response speed, efficiency and stability should be considered when the switching power amplifier is designed. In the power amplifier, PI circuit can make feedback current follow the given signal in time. In this paper, the amplifier adopts pulse width modulation (PWM) control strategy. The design of PI circuit, PWM circuit as well as the driving circuit were presented in the paper. After completing the designs of all parts, we choose MULTISIM as simulation software, which can establish an accurate circuit model. The simulation results show that the switching power amplifier designed in this paper has bigger bandwidth and less distortion and it can respond timely.

Abstract: This paper based on the improved twin tripod sliding universal joint and let it has the determined movement output. And create the three-dimensional model of twin tripod sliding universal joint before and after improved in software pro/e, and then put it into the simulation module, carry out the kinematic simulation of the tripod center on coupling. Obtained the curves of displacement, velocity and acceleration for two kinds of tripod centers.

Abstract: The structural and working principle of a kind of maglev linear feed unit for CNC engraving and milling machine tools are presented, and its mathematical model is analyzed, then its model of vibration is established in this paper. The modal analysis is made, the natural frequency is calculated with its vibration models, and the influence on the natural frequency of electromagnetic levitation bearing unit, which is caused by stiffness and damping coefficients of electromagnetic levitation bearing, is analyzed respectively by means of ANSYS software. The calculation and analysis presented in this paper can help us design the structure of the maglev linear feed unit for CNC engraving and milling machine tools, and can also establish a solid foundation for further etailed dynamics analysis.