Applied Mechanics and Materials Vols. 347-350

Abstract: In order to make common PC with the functions of receiving FM stereo broadcasting from the local FM radio station and collecting the temperature and humidity data in surrounding environment, a multifunction USB FM radio based on LabVIEW is presented in this paper. In the presented FM radio, the C8051F340 processor with on-chip universal serial bus (USB) peripherals is used as slave computer to control the Si4702 through I2C bus and the DHT11 through I/O port, and PC is designed to be host computer to get user instructions and connect and control the slave computer to finish the functions of receiving FM stereo broadcasting and collecting the temperature and humidity data by graphical user interface (GUI) programed by LabVIEW software and USB communication. Experimental results show that the presented USB FM radio has a friendly GUI and can be used feasibly and efficiently. Furthermore, new functions of the system can be extended by virtue of upgrading GUI program.

Abstract: Based on the introduction of the station power using system, this paper used fault tree analysis method to model the reliability of station power using system, which had been always ignored in traditional HVDC system reliability evaluation but actually had an important impact on the result of evaluation. Whats more, it assessed the reliability of the whole HVDC system (included station power using system) by means of frequency and duration method. Finally, an example was given to prove the correctness and validity of the proposed theory.

Abstract: It has been shown that none of any energy sources which own high specific energy or high specific power, but not both, can solely fulfil all the demands of hybrid electric vehicle (HEV) in some circumstances. In this paper a simulation model for battery/ultra-capacitor hybrid energy storage system (B/UC HESS) was presented by Matlab/Simulink. Based on the model a parameters sizing principle of the energy storage system is put forward from the angle of energy and power respectively. The results show that following this parameters matching principle, the B/UC HESS can meet the double requirements for power and energy in the operation process of HEV. Whats more, a good foundation is laid for HEV parameters optimization of the energy storage sources. The experiment results also show that the buffering effect of ultra-capacitor has optimized the charging and discharging processes of Ni-MH battery considerably.

Abstract: A clock generation circuit is proposed based on CMOSFET technology, which is comprised of a reference voltage source, a common source voltage amplifier, voltage controlled oscillator and timing circuit. By which a particular clock is produced, whose duty cycle is less than 50%. It is used 0.5 μ s CMOS process, HSPICE simulation results indicates that the average frequency of clock signal is 2.071MHz, and the average duty cycle is 31.565% .

Abstract: Concentrator is the central part of the energy information collection and management system. It can stay online for a long-term, and is stable and reliable. It has powerful ability in information acquisition and processing. Compared with other detection equipment, concentrator is the best platform to do the PLC network detection. This paper designed a set of embedded PLC network detection concentrator. The design based on ARMS embedded platform, ARM-linux system to achieve concentrators operation and inspection function, and also based on PLC-Modem to achieve recording of the carrier energy meter. Therefore,users can select different detection schemes to test the status of electric power carrier communication network.

Abstract: Static var Compensator (SVC) can suppress the voltage fluctuation, flicker and rapidly compensate the reactive power and the quality of electric power can be improved. In this paper, a new calculation method of reactive susceptances based on balance principle was proposed, which only uses the fundamental positive reactive and negative active & reactive components, and was analyzed and verified by simulation and dynamic test. The results of simulation and experiment show that the method can achieve the dynamic compensation of reactive power of the unbalanced load, and it is accurate, rapid and efficient.

Abstract: High voltage 4H-SiC junction barrier schottky (JBS) diode with breakdown voltage higher than 4.5 kV has been fabricated. The doping level and thickness of the N-type drift layer and the device structure have been performed by numerical simulations. The thickness of the device epilayer is 50 μm, and the doping concentration is 1.2×1015 cm3. A floating guard rings edge termination has been used to improve the effectiveness of the edge termination technique. The diodes can block a reverse voltage of at least 4.5 kV, and the on-state current density was 80 A/cm2 at VF =4 V.

Abstract: Energy storage capacitance is necessary part of pulse power generator. Generally, it is difficult to match the equivalent capacitance in high voltage side and energy storage capacitance in low voltage side of the pulse transformer. Resultantly, it requires high flow capability of switch device. In this paper, three methods are presented to solve this problem based on reasons of overcurrent. The results of simulation and experiments show that the efficiency of generator was higher with the method of thyristor and inductance in reverse parallel, and this method would be the most effective resolution.

Abstract: The automatic voltage control system in regional power grid is a significant measure to improve the system voltage and the power quality. It relies on online reactive power optimization. This paper proposes a novel algorithm aimed to build an online reactive power optimization model, which uses a hybrid algorithm combined the primal-dual interior point method and branch and bound method. Dealing with the discrete variables and continuous variables separately, the solution speed and accelerate convergence problem is improved rapidly. Finally, the efficiency of the proposed method is verified by numerical simulation in a regional power grid system.

Abstract: Automatic voltage control (AVC) system has been widely used in power systems at home and abroad, with some problems in applications. This paper proposes a closed-loop testing method based on real time digital simulation system (RTDS) and reactive optimization procedures to simulate the actual AVC operation mode, we can obtain an optimal control which is different from the actual AVC system, it can be used as the actual AVC system judgment to evaluate the action effectiveness and the advantages/disadvantages of the actual AVC system compared with optimal results. Finally, the simulation tests show that RTDS-based reactive power and voltage optimization control method is good so that it can be regard as reference to evaluate the control effectiveness of the actual AVC system action.