Papers by Keyword: Dynamic Performance

Abstract: Power amplifier is an important part of maglev control system and it may need lots of time and manpower at regulating PI parameters. To solve this problem, an equivalent model was proposed to simplify the parameter adjustment. In this paper, firstly, mathematical model of the power amplifier was proposed and the Simulink model was built in Matlab software. Then the experimental platform was established and dynamic properties of the power amplifier were studied by simulation and experiment. The results show that the overshoot and rise time of experiment and simulation results matches well and the error of cut-off frequency is less than 10%. Therefore, it has instructional significance for parameters design.

Abstract: This paper deals with parameter optimization of virtual impedance of parallel inverter. Conventional design methods determine parameters by observing the changes of amplitude-frequency and phase frequency curves of the equivalent impedance. However, those methods always neglect the dynamic performance of inverters in parallel. This paper proposes a novel method to optimize the coefficients of virtual impedance and experiments show that new method improves the dynamic performance of parallel inverter effectively, as well as stability and flexibility.

Abstract: With the rapid development of technology of bridge, bridge as an important part of the traffic network, the safety of its operations was getting more and more attention by people. In order to ensure the bridge can be safe and reliable operating, the newly built bridge testing had become a necessary measures. In this paper, a three span continuous box girder bridge (28+36+28m) was taken as an example, To analyze and calculate its dynamic characteristics, the finite element software MISAS was used. And it was verified through experiments.

Abstract: In order to investigate the effect of swirl intensity on the performance of the diesel engine, the 4JB1 diesel engine was taken as the research subject and KIVA-3V program was used to calculate the temperature, pressure, NO_x and SOOT in cylinder and the performance of dynamic and economy of the diesel engine by changing the value of swirl ratio. The results show that increasing the swirl ratio in the cylinder can make the hybrid combustion of fuel and air sufficiently, improving the combustion temperature and pressure in the cylinder, enhanced the power of the diesel engine and reduced fuel consumption. The generation of NO_x increased with the increases of swirl ratio and the production of SOOT decreased with the increases of swirl ratio.

Abstract: Electro mechanical actuator (EMA) is an important type of power-by-wire (PBW) actuator. The dynamic performance of EMA is a key issue especially when it is mounted on a fighter aircraft. Generally, the EMA adopts permanent magnet synchronous motor (PMSM) as the drive unit. It is a position controlled cascade system with an inner current control loop. This study focuses on the current control loop and proposes a scheme which utilizes optimal current trajectory control to exploit the inherent torque capability of the motor. Compared with traditional current control, i.e. id=0 strategy, the torque capability of the motor is maximized and the speed range is expanded. This directly improves the EMA dynamic performance. Faster transient process is demonstrated experimentally, which verifies the efficiency of the proposed scheme.

Abstract: Experimental method and parameters to investigate the dynamic performances of an automatic tensioner are discussed. Parameters to evaluate the dynamic performances of a tensioner include dynamic stiffness, loss angle and equivalent viscous coefficient. Dynamic stiffness and loss angle can be measured directly, and the equivalent viscous coefficient can be calculated by torque-angular displacement loop which identified with the parameters including dynamic stiffness, loss angle, pre-load torque, pre-load angular displacement, excitation amplitude and excitation frequency. In this paper, the influences of excitation amplitude, excitation frequency and pre-load torque on the dynamic characteristics of tensioner are measured and investigated.

Abstract: In order to study the differences between spaces twisted backstay inclined tower cable-stayed bridge and conventionally cable-arranged cable-stayed bridge in mechanical property, this paper, taking a single-stay inclined tower space twisted backstays cable-stayed bridge as the study project, adopting FEM by changing the form of the backstays, makes a contrastive analysis on the difference between space twisted backstays cable arrangement (TBCA) and fan-shaped backstays cable arrangement (FBCA) in such aspects as static performance, dynamic property and stability. Some conclusions are concluded: the TBCA is easy to cause such problems as uneven distributed cable force, larger girders bending moment and stress; the integral rigidity of TBCA is less than that of FBCA; in stability, these two differ little, etc. As far as the overall comparison is concerned, TBCA is basically rational from the point of stress. However, while obtaining a certain visual effect, its mechanical property decreases somewhat.

Abstract: With the progress and development of modern society, various electronic equipments not only have been enriching our lives, but also have become an indispensable tool for people. At present, the electronic equipment is moving towards the direction of becoming more integrated, smaller and more accurate, which requires good dynamic performance and stability. This paper builds the finite element model and makes optimization and analysis for its structure through analyzing the dynamic performance of electronic components. On the basis of the analysis, this paper puts forward a new modeling method having the parametric substructure. In addition, the genetic algorithm is used to dynamically analyze and optimally combine the components on printed circuit boards. Finally through a concrete instance, this paper calculates its rationality and validity.

Abstract: Interlinked air suspension, which formed by interconnecting two or more air springs of traditional air suspension using switchable pneumatic pipe connections, can further improve vehicles riding comfort and driving stability. The structure and working principle of this suspension is introduced, the model of interlinked air suspension is developed and validated via experiments. Simulation results indicate that, the larger the diameter of connecting pipe, the smaller the stiffness of air springs, and interlinked air suspension can effectively reduce vehicles roll angle and vertical vibration under its first natural frequency, which greatly affects vehicles riding comfort.

Abstract: It is common for using light steel structure as an upper layer to alter the multi-layer frame structure. But it is easy to form vertical irregular structure of rigid upper and flexible bottom. And the mass, stiffness, period and damping ratio are change after layer-adding. So it should take a holistic analysis of the structure. By using sap2000 to simulate a two-layer steel frame with a portal frame added, the seismic performance was analyzed. The result shows: transfer floor was relatively weak, it requires attention when seismic design; damping ratio has a great influence to seismic, it should been chose reasonably.