http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Zhang, Baifu,Han, Xiaoqing,Meng, Runquan,Ren, Chunguang,Wang, Lei,Song, Tianhao,Liu, Yizhao The Korean Institute of Power Electronics 2021 JOURNAL OF POWER ELECTRONICS Vol.21 No.1
The redundant design of multi-paralleled bidirectional power converters (BPCs) provides technical support for hybrid microgrid systems to consume more distributed generations (DGs) and DC loads. However, the multi-BPCs also provide paths for circulating current. In addition, the AC sub-grid may operate under unbalanced conditions due to the consumption of single-phase loads and power electronic devices. In addition, unbalanced three-phase voltage deteriorates the generation of circulating current. In this paper, an adaptive virtual impedance control method based on second-order generalized integration (SOGI) is proposed to suppress circulating current on the basic analysis of circulating current generation mechanism, the equivalent model establishment, and the suppression principle. The virtual impedance is dynamically adjusted in real-time based on the power oscillation caused by unbalanced voltage. Moreover, an integral term is added to the reactive power droop control to realize the tracking of voltage without static error. Finally, the effectiveness and feasibility of the proposed control algorithm are verified by experiments. The research results show that the proposed control method can optimize the damping characteristics, reduce the voltage difference between the BPCs, and improve the current sharing effect.
Mechanical and Tribological Properties of Short Basalt Fiber-reinforced Polyoxymethylene Composites
Chenghe Liu,Chunguang Long,Lei Chen,Junpeng Liu,Taishan Cao,Jian Zhang 한국고분자학회 2016 폴리머 Vol.40 No.6
In this paper, short basalt fiber-reinforced polyoxymethylene (POM) composites were prepared by melt blending and injection molding. The mechanical and tribological properties of the composites were studied by an orthogonal experiment. It was found that the optimal combination of fiber length 4 mm, fiber content 20 wt% and treated with KH550 would result in a comprehensive property which is 27.45% higher tensile strength, 9.65% higher impact strength and 18.11% higher flexural strength with compared to that of pure POM. But its tribological properties would be worse with the addition of the basalt fibers. After incorporating 10 wt% of polytetrafluoroethylene (PTFE) into the composites, the tribological properties of the composites was improved, closed to that of pure POM, with an insignificant decrease to their mechanical properties. Moreover, the morphology of fracture surfaces and worn surfaces evaluated by scanning electron microscopy showed good agreement with the results of the literature.
Simulation of the damping effect of a high-rise CRST frame structure
Xilin Lu,Chunguang Meng,Hongmei Zhang 사단법인 한국계산역학회 2012 Computers and Concrete, An International Journal Vol.9 No.4
The damping effect of a Concrete-filled Rectangular Steel Tube (CRST) frame structure is studied in this paper. Viscous dampers are employed to insure the function of the building especially subjected to earthquakes, for some of the main vertical elements of the building are not continuous. The shaking table test of a 1:15 scale model was conducted under different earthquake excitations to recognize the seismic behavior of this building. And the vibration damping effect was also investigated by the shaking table test and the simulation analysis. The nonlinear time-history analysis of the shaking table test model was carried out by the finite element analysis program CANNY. The simulation model was constructed in accordance with the tested one and was analyzed under the same loading condition and the simulation effect was then validated by the tested results. Further more, the simulation analysis of the prototype structure was carried out by the same procedure. Both the simulated and tested results indicate that there are no obvious weak stories on the damping equipped structure, and the dampers can provide the probability of an irregular CRST frame structure to meet the requirements of the design code on energy dissipation and deformation limitation.
Acid-insoluble Substances in Reduced Iron Powder from Ores
Wang Chonglin,Zhang Chunguang 한국분말야금학회 2006 한국분말야금학회 학술대회논문집 Vol.2006 No.1
X-ray analysis on iron ores and reduced iron powders revealed that the main acid-insoluble substances were hexagonal and tetragonal quartz, another substances were sillimanite, alumina-silicate, an unnamed zeolite, all contained Si and Al. Their particle size was in the range of . Statistics analysis showed that the AIC for high-grade magnetite powder was ) during the latest five months. The predicting value for reduced iron powder should be 0.179%. However, the testing value for reduced iron powder was . The limited difference of 0.013% might imply rare pollution coming from the reduction and milling processes. The most important step for control AIC should be the separation process of iron ore powders.
Genetic Analysis of Generalized S-Transform
Yun Lin,Xiaowan Yu,Chunguang Ma,Zheng Dou,Zhiqiang Wu,Zhiping Zhang 보안공학연구지원센터 2016 International Journal of u- and e- Service, Scienc Vol.9 No.4
This text starts with the short time Fourier transform and continuous wavelet transform to deduce the generalized S-transformation. From the point of generation views, we analyzed a relative relationship between generalized S-transformation and the short time Fourier transform, and the other relative relationship between generalized S transform and continuous wavelet transform. The article gives the definition of “the gene mutation of formula” and “the genetic restructuring of formula”, and introduces the deriving process of the two core concept. Theoretical analyses show that generalized S-transformation inherited the desirable characteristics in short time Fourier transform which use the window function to select suitable signal. Through genome sequencing of specific parameters, generalized S-transformation has a stronger adaptation that the time-frequency window could make real-time adjusting of frequency. Moreover, generalized S-transformation breaks out limitation that the wavelet function has to content the admissible conditions. From the point of gene mutation, we give the definition of “the gene mutation of formula”. Based on the structure form of wavelet functions, we define the generalized S-transformation with a wider domain of definition. Generalized S-transformation inherited the desirable characteristics of the short time Fourier transform and continuous wavelet transform. It has great utility and flexibility in analyzing non-stationary signals.
Modular DC Solid State Transformer with Fault-Tolerant Function
Xiangqi Meng,Yanbing Jia,Chunguang Ren,Xiaoqiang Lin,Baifu Zhang 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5
A modularized control method with faulttolerant function is proposed under the condition that a module of DC solid state transformer (DCSST) fails due to input short circuit. The decoupling control strategy is deduced by establishing the mathematic model of the DCSST. The maximum input voltage is selected as the reference voltage by adding diodes at the input side. The proposed system can automatically adjust the input voltage reference to keep the output voltage stability for the module in DCSST with short-circuit fault. Simulation and experiment results show that the proposed control method can decouple the output voltage and the input average voltage, maintain the output voltage stable and improve the reliability of the system when a short circuit occurs in a module of DCSST.
The Recognition Method of Radiation Source Based on Information Entropy and Cloud Model
Yun Lin,Can Wang,Chunguang Ma,Zheng Dou,Zhiqiang Wu,Zhiping Zhang 보안공학연구지원센터 2016 International Journal of Grid and Distributed Comp Vol.9 No.2
Information entropy features are often used for radiation source signal recognition, but due to the information entropy is very sensitive to noise, so this method has greater recognition rate changes with the SNR. This paper putting forward a viable recognition based on Entropy and cloud model. using cloud model to extract secondary features of signals, build radiation source signal’s entropy and cloud feature vector. The method uses cloud model description and processing interval fuzzy and observation noise data, better solve the low SNR cases of radiation source signal feature extraction problem. At the same time, putting forward the similar cloud classification recognition algorithm based on cloud model. The simulation results show that Entropy and cloud model has better recognition effect under low SNR, which can improve the signals’ recognition rate under low SNR.