Applied Mechanics and Materials Vols. 687-691

Abstract: OpenFOAM is a widely used open source computational fluid dynamics (CFD) , and the performance of its application is critical for the CFD user, and many researchers try to optimize it from various perspectives. In this paper, we try to optimization OpenFOAM application from the compiler perspective, which is the simplest way to get the optimization affect. We compare two mainstream compilers: Intel compiler icc and an open source compiler, as well as a serious of optimization option flags. Through the experiment, we find that Intel compiler has a much better performance than gcc, which is up to 9.88%, and a suitable combination of the optimization option flags is important to the compile performance.

Abstract: This paper designed an automatic irrigation system based on ZigBee, and the system is powered by solar energy. It can provide users with an intuitive on-site system management platform to complete node management and data processing functions. This paper develops a server-side information management system software, achieving real-time monitoring and remote monitoring alarm by the Web, and it simplifies the process of installation and disassembly field devices, making it more suitable for a direct connection of the general inconvenience of monitoring occasions. This article will play a reference role in intelligent irrigation.

Abstract: Congestion management is a hot point for research in power system. Optimal power flow (OPF) model is often used to solve this problem. However, the results cannot satisfy with market needing. To solve this problem, this paper presents a novel method of congestion management based on risk constraint and fuzzy optimization in electricity power markets. The risk constraint is used for transmission line thermal security instead of the traditional deterministic current or power constraint. The multi-objective functions are used to coordinate the conflict between security and efficiency of transmission network. Primal-Dual Interior Point Method (PDIPM) is adopted to solve the RBOPF problem. The method can minimize re-dispatch cost and the system operating risk.

Abstract: Voltage is a key factor not only to power system but also to user. Keep voltage steady is a hot point for researching. Paper proposed keeping steady voltage and improving power quality by using intelligent auto voltage control system. This method is based on the existing power system software and hardware platforms. It is of the advantages of mature technology, small investment, and can improve user’s power quality effectively. Second, the application of auto voltage control on textile manufacture is analyzed. It can improve running environment of textile devices and textile quality

Abstract: In the view of the safe and stable operation of power system in the extreme environments, the status and the role of two typical provincial power systems in China were analyzed. Combined with the spatial and temporal distribution characteristics of this total solar eclipse in July 22, the operations of the two provincial power systems in different regions during the total solar eclipse were compared. The main impacts of the development process of the total solar eclipse on power systems were analyzed. At last, combined the development trend of the extreme environments in the world, how to reduce the running risk of power system in the extreme environments by the crisis dispatch was explored.

Abstract: Line flow is one of the key factors which dominate the power system security. To deal with this problem, this paper proposed a method of power system assessment and control based on power system Line flow risk. Probabilistic power flow (PPF) is used to analyze the random of system statuses. The severity function is used to describe the impact of the transmission line load. Line flow risk is defined as the result of the probability multiplying the severity of Line flow. It is an indicator of power system security. This reduces the system line flow risk and increases the system security.

Abstract: Optical fiber data transmission system has advantages of long-distance transmission, low error rate, high speed data transmission, using FPGA chip NIOSII embedded processor and on chip peripheral constitute the core components, without changing the basic framework of the system, can be upgraded and functional changes to the FPGA internal hardware and software, improved design flexibility, reduced the development cost.

Abstract: The system test results show that the system modules can run normally. When the infrared detection circuit, Zigbee accept module detects information, microcontroller will drive the relay open the lights and headlamp unit, or shut down. In the display, dot matrix can work normally, can carry on the automatic control the fan, DHT11 sensor to detect the indoor temperature, can work normally. Through repeated tests, ZigBee protocol based on HOLTEK microcontroller remote intelligent control system successfully developed bath bully.

Abstract: With consideration of energy utilization and environmental protection, a solar thermoelectric air conditioner is designed, its composition characteristics, working principle is introduced, and factors that affect its performance have been analyzed theoretically.

Abstract: An optimization of PID controller based on indices of linear quadratic state and integration of error (IE) for Buck system is proposed. The optimal original disturbance suppression can be settled well by linear quadratic regulator (LQR) method, while assignment its weighted matrix Q and R is a matter. On the state space description of typical 2-order system, the equations among diagonal weighted matrix, parameters of PID, and characteristics of closed loop system have been established. With this, the steady, rapid and accurate nature of control system are expressed explicitly with the weighting matrix, and optimization of integral error can be easily solved due to integral velocity with constraint of given damping ratio. At last, LQR based optimal control systems with various Q for Buck are simulated, and simulations show the proposed approach have the dual optimality due to disturbance suppression.