Applied Mechanics and Materials Vols. 303-306

Abstract: This article puts forward object-oriented Petri net modeling method, which possesses good encapsulation and modularity compared with current ordinary modeling method. On the macro level, it divides the re-entrant lines into different object modules according to the technology, so that the complexity of models is largely reduced through message delivery between objects. In the micro level, it explains objects' internal operational mechanism, in another word, each object's internal operation cannot be affected by other objects and environment. At last, it makes modeling and dynamic analysis by taking LED chips' processing flow for example, showing that re-entrant lines model based on object-oriented Petri net possesses good modeling ability.

Abstract: At present, in Northwest China, due to sparsely populated, there are a considerable part of the nomads, but in the northwest region of sunshine a long time, solar energy is not very extensive, and for night life, is certainly more boring and boring Therefore, the system just to meet the need.

Abstract: In order to reduce excitation system swing and resultant reactive power swing, namely, reduce external electromagnetic interference to stable operation of 600MW generating unit, the paper analyses unit excitation control mode and designs hardware and software of excitation system. First, digital microcomputer control system organization was designed based on nonlinear control theory, which had an increase of control mode such as PID control mode, nonlinear optimum electronic control (NOEC) mode besides original voltage difference and current control mode. Second, full duplex collocation configuration mode of excitation system was designed, namely two controllers were master-slave concurrent, and each controller could meet excitation requirement of various operation condition including constrained excitation. Finally, in electric network disturbance test, measured excitation system parameters recovered stably in 1020 ms such as stator voltage Ut, rotor voltage Uf, comprehensive amplified control voltage Uc, active power P and reactive power Q. It is verified that transient stability and unit operating condition are improved.

Abstract: According to the doubly-fed motor starting control technology specialty, this paper proposes a new doubly-fed motor starting control method. Using detection circuit to monitor rotor voltage of doubly-fed motor in starting process, this method realizes the smooth transition from the asynchronous mode to doubly-fed model by controlling the transient output of inverter. On this basis, built control platform based on PLC and general converter, study the related experiment. Theoretical analysis and experimental results show that the proposed control method is feasible, and suitable for doubly-fed motor starting control process, so it has great practical value.

Abstract: The radio frequency identification (RFID) based on time series modeling were introduced into electrode foil stereoscopic warehouse for increasing the working efficiency. The aluminum foil, etched foil and the formed foil, which were the materials in stereoscopic warehouse, could be expressed as time series formation in order to find the right foil volume precisely in the shortest time.

Abstract: This article focuses on the study of optimization of mixed-model assembly line modeling. Based on colored timed Petri net, it forms knowledge colored timed Petri net by introducing Agent technology and knowledge place. Through taking advantage of Agent technology, it modularizes each technique process of mixed-model assembly line and then makes the bottom-up hierarchical modeling, avoiding the complexity problem of traditional Petri net modeling. Such a model always possesses Agent's autonomy and intelligence while the knowledge place could resolve conflicts and deadlock problems in models.

Abstract: In order to realize remote monitoring and control for the environment of plug seeding, the environment control system based on GPRS was developed. The systems includes environment sensors, GPRS remote terminal unit (RTU), control unit and WEB server. Through the GPRS network to transmission the environment parameters, and upload data via the Internet to the web server. According the environment parameters, the server get the optimal control scheme based on model. Then transmit the control scheme to the remote terminal unit (RTU) through the GPRS network. The RTU get the control scheme, the control unit send the control signal to the control equipment. This system can achieve real-time control of environment parameters for plug seedling.

Abstract: As the shortcomings of traditional Web mode’s real-time systems, such as bad user experience, high delay and low response, this paper studies Ajax technology and Web mode, using the technology combining with Web2.0 and Comet to make the on-board emergency communication system faster and more flexible. The composition of the system’s hardware and software are designed and implemented in this paper. The experiment shows that using Web2.0 technology can provide good flexibility, scalability, flicker-free, quick response and high real-time quality, when it adapts to the basic function of the emergency communication system.

Abstract: Min-max stochastic optimization is a kind of important problems in stochastic optimization, which has been widely applied in subjects such as inventory theory and robust optimization and engineering field. In this paper, we present sample average approximation(SAA) method for a class of min-max stochastic optimization problems, based on a nonlinear Lagrangian function. Convergence of the SAA estimators are analyzed by means of epi-convergence theory,when the Lagrange multiplier vector is optimal and the parameter is small enough.

Abstract: According to the structure and information flow of the active control system of large-scale wind farm, a load allocation scheme is proposed considering the wind speed fluctuations within the cluster, i.e. deciding the de-load depth of each turbine according to wind speed fluctuation when the farm is running under AGC mode, using wind turbine generator (WTG) de-load ability to reduce the impacts of wind speed fluctuations on the entire wind farm output. Use particle swarm optimization, prediction of WTG generation, wind speed fluctuation condition, wind scheduling instruction information to calculate the WTG de-load depth risk factors, and get the de-load power order distribution scheme. A simulation of 10 2MW WTGs shows that, load allocation scheme considering the wind speed fluctuations can reflect the relationship effectively between wind speed condition and output reliability, and promote the stability of wind farm output.