Applied Mechanics and Materials Vols. 143-144

Abstract: In this paper, a model of unit motor (16p15s) which is used for vertical elevator has been set up. And a modification of the primary geometry has been presented. In the new geometry, pole shoes are affixed to the primary poles. The finite element analysis (FEA) of various width of pole and different width of pole shoe have been carried out in this paper. The results show that the force profile of the proposed PMLSM has been improved. The minimum force ripple occurs in a suitable width of the pole shoes. And the back EMF constant is analyzed, too.

Abstract: To aimed at the synchronous control for dual-cylinder with unbalanced and uncertainty loading, this paper proposes a hybrid control method that consists of feed-forward control and fuzzy feedback control. In the first, a feed-forward controller of each cylinder based on trajectory restrains is developed to limit the motion and synchronous error to a certain extent, and also smooth the piston motion. Then, two fuzzy controllers are specified to improve the tracking performance of cylinder and compensate the synchronous error. The simulation experimental results show that the proposed hybrid control strategy can control the maximum synchronous error of the total system to be within ±10mm under the consideration of large load imbalance, and has the system motion of a good smoothness.

Abstract: As the rise both of the ships tonnage and the level of electrification heightened, the capacity of the ship power station has also been increased. Therefore, more large-capacity vessels generating units are used to satisfy the needs of the power system in the ship. This paper, by using the PSCAD simulation software, a dynamic simulation model of ship power system is established based on model elements such as prime mover, generators, control device, motor and the related load, based on which the defined load operating process is studied, and the steady state and dynamic performance of the ship power system are obtained. In order to energy saving and make full use of solar energy, in the ship power system, a photovoltaic device is used, and its output DC power is converted into the ship system using three-phase AC power by a inverter. For such a power system, the influences of addition of large-scale energy storage and new power supply equipments on ship power system are analyzed.

Abstract: Based on a detailed modeling of supercavitating flight, the Equivalent Pressure Center (EPC) method is proposed in this paper. To validating the proposed method, both of EPC and integrated moment, which are highly concerned during configuration design process for supercavitating motion, are studied for different configuration parameters including aspect ratio, fin position and cavitator size of the body. As the relative pitch angle between cavity and the vehicle would change with flight status, well designed vehicle configurations could produce better stability and maneuverability performances by locating the EPC close to the mass center. With detailed analysis of the EPC result, some of the propositional results for configuration parameters of supercavitating vehicles are given.

Abstract: An active suspension system has been proposed to improve the ride comfort. A quarter-car 2 degree-of-freedom system is designed and constructed on the basis of the concept of a four-wheel independent suspension. The aim of the work described in the paper was to illustrate the application of fuzzy Proportional Integration Derivative (PID) technique and Linear Quadratic Guass (LQG) control to the active suspension control system. The paper describes also the model and controller used in the study and discusses the vehicle response results obtained from a range of road input simulations. This work describes some comparison of active suspension fuzzy PID control and LQG control design method by MATLAB simulations. Simulation results show that the LQG controller achieved better performances in all carried-out investigations.

Abstract: Bond Graph theory is a powerful tool in the field of dynamics and multiple-energy domains analyses of complex engineering systems. On the purpose of analyses the dynamic characters of Stirling Engine fuel supply system, the author built a Stirling Engine fuel supply system model based on Bond Graph theory, derived the state equations including pump system and hydraulic system equations and built the Simulink model for simulation, finally verified the accuracy of the model through experiment.

Abstract: Through an analysis of tractor traction balance, a mathematical model which can easily calculate the traction force and efficiency of tractors under different operating conditions was built up, this model offers a basis for tractor-implement matching. Bases on above analyses, the best efficiency rating value was deduced and the traction characteristic curve was also plotted, this study provides a theoretical basis for tractor traction characteristic research.

Abstract: This document presents a solution for controlling a permanent magnet synchronous motor(PMSM) for the coal mine of DC lines of electric locomotive using the Texas Instruments (TI) TMS320C2407A digital signal processor (DSP). The control method presented relies on the vector control technology and space vector pulse width modulation (SVPWM) technology, the control algorithm maintains efficiency in a wide range speed. This document describes the structure features of the converter, power electronics, the keyboard display and the auxiliary power supply, hardware implementation and software design. Experimental results show that the system has better static and dynamic performance, completely fits the DC lines of electric locomotive operation. This document describes a practical solution and corresponding result, and this research has been applied successfully in practical work.

Abstract: There are many kinds of ADC chips which are analog or analog-digital mixed at home and abroad. It can not be integrated into a pure digital chip, in this paper, a way to realize quasi-digital 16- bit ADC based on stochastic logic was given. Except few analog elements, all are digital circuits. The paper describes the design principle and presents the simulation and hardware test results based on FPGA chips produced by Altera show that the shortest conversion time can reach 0.8ms. The hardware test shows that the design is successful.

Abstract: Different from the traditional rotary motors in structure and running state, it is difficult for permanent magnet linear synchronous motor (PMLSM) to build its precise mathematical model by analytical method and the asymmetry of the three-phase winding electromagnetic and electrical parameters of open PMLSM in a low-speed working zone is impossible to take into account. In this paper, considering the structural and running characteristics of PMLSM, a non-linear, asymmetric and variable parameter space state model is built. Then a finite element calculation and actual measurement of the required inductor values of a space state model with a prototype PMLSM are done respectively, and the influence of air-gap on the inductance parameters is analyzed.