Applied Mechanics and Materials Vol. 678

Abstract: Lifetime enhancement has been a hot issue in Wireless Sensor Networks (WSNs). To prolong the network lifetime of WSNs, this paper proposes an intelligent routing algorithm named RLLO. RLLO makes uses of the superiority of reinforcement learning (RL) and considers residual energy and hop count to define the reward function. It is to uniformly distribute the energy consumption and improve the packet delivery without additional cost. This proposed algorithm has been compared with Energy Aware Routing (EAR) and improved EAR (I-EAR). Simulation results show that RLLO gains a significant improvement in terms of network lifetime and packet delivery over these two algorithms.

Abstract: With respect to the application of high-speed, high-resolution A/D converter, the design and implementation of a CMOS input buffer is introduced. The buffer features high-speed and high-linearity. Its performances have been verified in a 14-bit 250MSPS pipelined A/D converter which is developed in 0.18um CMOS-based process technology. The simulation shows that the SFDR of the buffer is up to 104dB at an input clock of 250MHz with an input signal of 25MHz.

Abstract: This paper discussed a input buffer structure with replica load, analysed its theory of improving input signal linearity and decreasing distortion, gived some circuit embodiments, one of which was used for a 12-bit 500MSPS SHA-less ADC based on BiCMOS technolgy, Spurious Free Dynamic Range (SFDR) reached above 90dB with a 250MHz input signal.

Abstract: As one of important reactor control systems, Rod Control Rod Position System (RGL) is used for driving the rod, lifting or inserting in order to achieve reactor neutron balance. It plays an important role on ensuring safety operation and improving load factor of nuclear station. This paper introduces a current test system for driving the rod based on LabVIEW, which including test principle, software and hardware design and conclusion. The result indicates this systemic function is correct and meets the requirements. It can be used for current test of RGL system.

Abstract: This paper illustrates the operating principle and design characteristics of a start compensator for medium-sized asynchronous motor powered by Mobile power cars, and describes its application combined with engineering examples. The start compensator detects the motor phase current in real time by using current transformer to determine the switching time of change-over switch in the start compensator. The start compensator operates in a master-slave control mode and can be used as slave computer to communicate with PC based on MODBUS protocol. Its operation is controlled by means of a PC software interface. The whole control system is characterized by reliable performance and low manufacturing cost .

Abstract: In order to optimized the power cable layout design in tunnel, and improved the operation ability of the cable line, this paper analyzed the cable rating and the short-circuit force under different arrangements. 220kV cable circuit was simulated in the tunnel with conditions of the flat and the trefoil arrangements. The temperature and the rating of the 220kV cable under the condition of the two arrangements were calculated in this paper. The short circuit force peak value and its direction of the cable line under short circuit current of 50kA under the condition of the two arrangements were simulated in this paper. The results show that, the cable rating in flat arrangement is better than in trefoil formation. The value and the direction of the short circuit force in tunnel are better in flat arrangement than in trefoil formation. So it is suggested that the flat arrangement is preferred when conditions permit.

Abstract: Many reasons of low voltage in distribution network of Zhejiang province were investigation owing to many complaints from the areas. Because of a mass of site visits, simulation models were built to prove reasons of low voltage. The reason statistics of the transformer districts over the province list several proportions for the problems. Lastly, five advices were obtained to solution low voltage including planning, design, construction, reactive compensation and remote monitoring. It is helpful for solving the problem pertinently.

Abstract: In order to improve the dynamic behavior of the weak link in power transmission and distribution network, studied a new regulator using the divergence operator to disturbance, improve power and high voltage power system, the divergent regulator based on the frequency response characteristics were simulated using the DIgSILENT software, the effect of good.

Abstract: In order to improve the virtual flux oriented vector control performance of PWM rectifier, an improved observation method of virtual flux-linkage is proposed. To avoid the relevant problems of pure integrator, and to achieve the accurate observation of the grid voltage’s phase, three first order low-pass filters are cascaded to displace the pure integrator. Based on the SVPWM modulation module and the presented algorithm, grid voltage sensorless control system of three-phase PWM rectifier is given. Simulation results have shown that: either in rectifying or inverting status, the amplitude and phase of virtual flux-linkage can be observed accurately, i.e. the control system of PWM rectifier can operate reliably without the grid voltage sensors; the presented estimation method of virtual flux-linkage is effective.

Abstract: This paper presents and analyzes a power oscillation phenomenon caused by the non-linear segment of valve discharge characteristics of the steam turbine. The torque analysis method is applied to explain how the mechanical torque considering the valve discharge characteristics impacts the damping characteristic of the power system. Simulation studies are based on a single-machine infinity bus system by using Matlab/Simulink. Analysis and simulation results reveal that the effect of the prime mover should be fully considered while analyzing the low frequency oscillations.