Advanced Materials Research Vols. 756-759

Abstract: The paper introduces per-unit system for single Doubly-fed induction generator (DFIG) and large scale wind farm (LSWF) equivalence, based on which their modeling, including main circuit, linkage equation, power equation and rotor motion equation, are built, and equivalence method of LSWF are present. The single DFIG wind farm system and LSWF are built respectively on Real time digital simulator (RTDS). Comparing simulating results of single DFIG with those of LSWF, conclusion shows per-unit value system is correct, equivalent method is feasible.

Abstract: It is become a relative mature technique now that Active Power Filter can do harmonic suppression and reactive compensation to alternating current net of nonlinear load. This paper contrasts passive and active filter technology in harmonic suppression, and introduces the classification of passive filter as well as working principle. This paper also discusses current-source APF consisting of multi-modular and phase shifted SPWM converters and cascade multilevel converters applied in current-source APF which can carry out high switch frequency effect under the lower switch frequencies. Finally, this paper gives a comprehensive discussion on APF technique and prospects its development in China.

Abstract: In this paper, a 12-bits DAC in 0.18um SiGe HBT process is presented. The DAC consists of a 4:1 MUX, standard input interfaces and LVDS output. The DAC consumes 1.8W power under a 3.3V power supply. The simulation results show that the SFDR of the DAC is 81dB, and the converter can be operated at a sampling rate up to 2GSPS.

Abstract: Dielectric loss is caused due to imperfect dielectric insulation, in order to study the impact of the dielectric loss consider a uniform loss transmission line with leak conductance. The BLT equation from the frequency domain to time domain is derived to improve the time domain BLT equation, and the aim of using the time domain BLT equation to calculate load voltage of the transmission line with transient signal source, through the calculation results to analyze the impact of the dielectric loss. The results showed that the attenuation of the terminal load transient response voltage occurred when the dielectric loss exists, and this effect is nonlinear.

Abstract: By the excitation of the electromagnetic signal, double transmission line will inducing a voltage and current, thereby creating the space radiation field. Based on infinitesimal current source radiation field and by the convenience of the terminal response aspects of solving transmission line of BLT equation, the double transmission line is derived and gets the analytical solution.

Abstract: In order to meet the needs of the power communication device This paper discusses the key technologies of the power switching equipment based on ATCA structure, including network topology selection and rack management system, as well as a system performance test result is given. The test results show that the power switching equipment based on ATCA structure has good rack management ability, and it can monitor and adjust parameters such as system temperature. It can realize hot backup of the system, making the system with high reliability and high transmission bandwidth.

Abstract: A high speed open-loop track/hold circuit in 0.18um CMOS process is presented. Open-loop and differential architecture are adopted to obtain high bandwidth and high speed;time-interleaved structure is used to reach a high sampling rate;source negative feedback and offset compensation are used to improve the linearity of the circuit.Simulation results show that with 396.875MHz input, 1.6GSPS sampling rate, driving the pre-amplifier of ADC, the thack/hold circuits SFDR(spurious-free dynamic range) is 75.8dB,satisfying the demand of 12 bits ADC.The circuit features high sampling rate,wide bandwidth,high SFDR and universal.

Abstract: the new method-AHM, and nine parameters which included diameter, delivery pressure, pressure ratio of the first station, pressure ratios of intermediate stations, number of stations, investment costs of pipeline ,investment costs of stations, investment costs of operation ,equivalent cost, have been selected to evaluate design projects of the long distance natural gas pipeline. The results indicate that attribute AHM matches other methods well. The calculation result of the example indicates that AHM method can get a good assessment result for the multifactor and multi-hierarchy complicated problems. The study provides a new method and technique for designers to select the technical feasible and economic reasonable design case, which has some theoretical and practical value.

Abstract: This paper establishes an assembly planning model combined with the actual assembly process of the complex equipment and based on the equipment characteristic & interactive features. Adding constraints model for complex assembly steps which ensure the assembly validity by the hierarchical constraint assembly drawing built through a detailed analysis of complex constraint relations between the blocks and layers. The fact shows that the model can effectively express the establishment of the assembly sequence based on the equipment level information and hierarchical constraint relations, and in order to achieve the assembly relationship the decomposition and timing, make the interactive process is simple and easy to operate.

Abstract: To analyze he load of the frame for pavement cold recycling machine. Firstly, the general conditions of the cold recycling machine was analyzed, the load impact factors and classification of cold recycling machine were expounded. Secondly, the load analysis was carried out by simulate the suffer force of machine and frame. Finally ,the reaction force of The front and rear Wheel are 103164N and 165471N, and the rolling resistance of the front and rear wheel are 2063N and 3309N, Horizontal direction force component of cutting force is 28800N,and perpendicular direction force component of cutting force is 23635N