Research on the Control Strategy of Photovoltaic Power Generation System Based on the Micro Grid

Hong Gang,Peng Qiu,Yibo Zhang 보안공학연구지원센터 2016 International Journal of Grid and Distributed Comp Vol.9 No.8

With the rapid growth of the electricity demand, UHVAC and UHVDC transmission and the distributed generation with the renewable energy become the key point of the development of power industry based on the goal of the harmonious development in the power industry at home. According to the certain topological structure, the micro grid is the network including the distributed power supply, energy storage power supply, and load-control devices. It is linked with the grid through the switch devices, realizing the effective management of the distributed generation. We can also find the value and benefits of the distributed generation for the power grid and the user. This paper discusses that the micro grid is the effective approach to solve the integration between distributed generation and power grid. It also summaries its concept and research status of the micro grid deeply. Then it knows the current application of photovoltaic power generation technology. Finally it concludes that the operation characteristic of the photovoltaic power generation system has the important research value in the micro grid.

Collision-Free Arbitration Protocol for Active RFID Systems

Honggang Wang,Changxing Pei,Bo Su 한국통신학회 2012 Journal of communications and networks Vol.14 No.1

Collisions between tags greatly reduce the identification speed in radio frequency identification (RFID) systems and increase communication overhead. In particular for an active RFID system, tags are powered by small batteries, and a large number of re-transmissions caused by collisions can deteriorate and exhaust the tag energy which may result in missing tags. An ef-ficient collision-free arbitration protocol for active RFID systems is proposed in this paper. In this protocol, a new mechanism involving collision detection, collision avoidance, and fast tag access is introduced. Specifically, the pulse burst duration and busy-tonedetection delay are introduced between the preamble and data portion of a tag-to-reader (T-R) frame. The reader identifies tag collision by detecting pulses and transmits a busy tone to avoid unnecessary transmission when collision occurs. A polling process is then designed to quickly access the collided tags. It is shown that the use of the proposed protocol results in a system throughput of 0.612,which is an obvious improvement when compared to the framedslotted ALOHA (FSA) arbitration protocol for ISO/IEC 18000-7 standard. Furthermore, the proposed protocol greatly reduces communication overhead, which leads to energy conservation.

Simulation of in-situ preheating of ni-based multi-layer and multi-pass coatings on H13 steel

Honggang Yin,Jinhua LI,Liwei Zhao,Fangping Yao 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.9

COMSOL was used to simulate the temperature field of the preheating and nonpreheating processes of the laser cladding multi-layer and multi-pass coating, and experimental verification was carried out. The results show that the temperature gradient value of the coating at the Z-axis is much larger than the value at the X and Y-axis, respectively. It indicates that the coating is sensitive to cracks at the Z-axis. After preheating, the quality of the coating is improved, and the results of the geometric morphology in experiments are basically consistent with the results of simulation. With increase in coating temperature, the cladding efficiency increased. The difference of temperature between the first and second layer was significantly reduced. The temperature gradient value at the Z-axis decreased. The coating grain structure presents as refined and well-distributed. The temperature gradient size in each layer decreased with the number of coatings increasing.

Inverse Analysis in Hydroforming of a Refrigerator Door Handle Using MOGA

Honggang An,Daniel Green,Jennifer Johrendt,Klaus Hertell 한국소성가공학회 2010 기타자료 Vol.2010 No.6

An inverse problem of load path design in tube hydroforming of a refrigerator door handle is presented. The motivation is to inversely analyze the load path for tube hydroforming and verify the applicability of developed algorithms. Several parameters are given as inputs: the material properties of the pre-bent tube, the geometry of the tube and the die. The study also investigates the influence of the coefficient of friction (COF) at two levels: with COF of 0.1 and 0.05. The process parameters with regard to pressure and end feeding are to be determined. An optimization strategy using MOGA was implemented to solve the inverse problem. In order to obtain a quality part without failure, six objectives were calculated to evaluate the forming severity and the final product geometry, namely, fracture/necking, wrinkling, severe thinning, die filling, and the maximum thinning ratio of tube thickness. The MOGA was coupled with finite element analysis (FEA) and used to optimize the load path. To reduce the calculation cost, a surrogate Kriging model was established to replace the FEA, and was updated every five generations. A Pareto optimal solution set was generated after 20 steps and the optimal load path was determined with a minimum thinning ratio. The results were validated by both the FEA simulation results and the comparison of the optimal load path with the actual load paths. It was noted that the thinning ratio was less than 25% for the lower coefficient of friction (0.05) and the maximum stress was far below the forming stress limit. Meanwhile, the tube fully filled the die cavity and no failure occurred.

Cloning and Characterization of hydroxypyruvate isomerase (EC 5.3.1.22) gene in silkworm Bombyx mori

Lv, HongGang,Chen, KePing,Yao, Qin,Wang, Lin Korean Society of Sericultural Science 2008 International Journal of Industrial Entomology Vol.17 No.2

The sequence of hydroxypyruvate isomerase gene was obtained in NCBI. In this study, the hydroxypyruvate isomerase gene of Bombyx.mori was identified and annotated with bioinformatics tools. The result was confirmed by RT-PCR, prokaryotic expression, mass spectrographic analysis and sub-cellular localization. The hydroxypyruvate isomerase cDNA comtains a 783bp ORF, and has 4 exons. The deduced protein has 260 amino acid residues with the predicted molecular weight of 29169.30 Da, isoelectric point of 6.10, and contains conserved PRK09997 and Hfi domains. The hydroxypyruvate isomerases of Nasonia vitripennis and Bombyx mori have a high homology. Through RTPCR analysis, we found that this transcript was present in testis, ovary, blood-lymph, fat body, midgut, silk gland and tuba Malpighii. This protein was located in cytoplasm through immunohistochemistry. We submitted the cloned gene under the accession number EU344910. The enzyme has been classified under accession number EC 5.3.1.22.

Collision-Free Arbitration Protocol for Active RFID Systems

Wang, Honggang,Pei, Changxing,Su, Bo The Korea Institute of Information and Commucation 2012 Journal of communications and networks Vol.14 No.1

Collisions between tags greatly reduce the identification speed in radio frequency identification (RFID) systems and increase communication overhead. In particular for an active RFID system, tags are powered by small batteries, and a large number of re-transmissions caused by collisions can deteriorate and exhaust the tag energy which may result in missing tags. An efficient collision-free arbitration protocol for active RFID systems is proposed in this paper. In this protocol, a new mechanism involving collision detection, collision avoidance, and fast tag access is introduced. Specifically, the pulse burst duration and busy-tone-detection delay are introduced between the preamble and data portion of a tag-to-reader (T-R) frame. The reader identifies tag collision by detecting pulses and transmits a busy tone to avoid unnecessary transmission when collision occurs. A polling process is then designed to quickly access the collided tags. It is shown that the use of the proposed protocol results in a system throughput of 0.612, which is an obvious improvement when compared to the framed-slotted ALOHA (FSA) arbitration protocol for ISO/IEC 18000-7 standard. Furthermore, the proposed protocol greatly reduces communication overhead, which leads to energy conservation.

Constant amplitude fatigue test of high strength bolts in grid structures with bolt-sphere joints

Xu Yang,Honggang Lei 국제구조공학회 2017 Steel and Composite Structures, An International J Vol.25 No.5

The grid structure with bolt-sphere joints is widely adopted by industrial plants with suspending crane. The alternating reciprocating action of the suspending crane will cause fatigue problems of the grid structure with bolt-sphere joints with respect to the rod, the cone, the sealing plate, the bolt ball and the high strength bolt; while the fatigue of the high strength bolt is the key issue of fatigue failure. Based on efficient and smooth loading equipment with the AMSLER fatigue testing machine, this paper conducted a constant amplitude fatigue test on 18 M20 and 14 M30 high strength bolts with 40Cr material, and obtained 19 valid failure points, 9 unspoiled points with more than 2 million cycles, and 4 abnormal failure points. In addition, it established the constant amplitude fatigue design method, [Δσ]2×10 6 =58.91MPa, and analyzed the stress concentration and the fatigue fracture of high strength bolts. It can be explained that the geometrical stress concentration of high-strength bolt caused by spiral burr is severe.

Variable amplitude fatigue test of M30 high-strength bolt in bolt-sphere joint grid structures

Bin Qiu,Honggang Lei,Xu Yang,Zichun Zhou,Guoqing Wang 국제구조공학회 2019 Steel and Composite Structures, An International J Vol.33 No.3

Fatigue failure of a grid structure using bolt-sphere joints is liable to occur in a high-strength bolt due to the alternating and reciprocal actions of a suspension crane. In this study, variable amplitude fatigue tests were carried out on 20 40 Cr steel alloy M30 high-strength bolts using an MTS fatigue testing machine, and four cyclic stress amplitude loading patterns, Low-High, High- Low, Low-High-Low, and High-Low-High, were tested. The scanning electron microscope images of bolt fatigue failure due to variable amplitude stress were obtained, and the fractographic analysis of fatigue fractures was performed to investigate the fatigue failure mechanisms. Based on the available data from the constant amplitude fatigue tests, the variable amplitude fatigue life of an M30 high-strength bolt in a bolt-sphere joint was estimated using both Miner's rule and the Corten-Dolan model. Since both cumulative damage models gave similar predictions, Miner's rule is suggested for estimating the variable-amplitude fatigue life of M30 high-strength bolts in a grid structure with bolt-sphere joints; the S-N fatigue curve of the M30 high-strength bolts under variable amplitude loading was derived using equivalent stress amplitude as a design parameter.

Fatigue performance and life prediction methods research on steel tube-welded hollow spherical joint

Qi Guo,Ying Xing,Honggang Lei,Jingfeng Jiao,Qingwei Chen 국제구조공학회 2020 Steel and Composite Structures, An International J Vol.36 No.1

The grid structures with welded hollow spherical joint (WHSJ) have gained increasing popularity for use in industrial buildings with suspended cranes, and usually welded with steel tube (ST). The fatigue performance of steel tube-welded hollow spherical joint (ST-WHSJ) is however not yet well characterized, and there is little research on fatigue life prediction methods of ST-WHSJ. In this study, based on previous fatigue tests, three series of specimen fatigue data with different design parameters and stress ratios were compared, and two fatigue failure modes were revealed: failure at the weld toe of the ST and the WHSJ respectively. Then, S–N curves of nominal stress were uniformed. Furthermore, a finite element model (FEM) was validated by static test, and was introduced to assess fatigue behavior with the hot spot stress method (HSSM) and the effective notch stress method (ENSM). Both methods could provide conservative predictions, and these two methods had similar results. However, ENSM, especially when using von Mises stress, had a better fit for the series with a non- positive stress ratio. After including the welding residual stress and mean stress, analyses with the local stress method (LSM) and the critical distance method (CDM, including point method and line method) were carried out. It could be seen that the point method of CDM led to more accurate predictions than LSM, and was recommended for series with positive stress ratios.

Calculation of Thermal Stress Field with Non - Linear Surface Heat - Transfer Coefficient during Quenching

Cheng, Heming,Wang, Honggang,Huang, Xieqing 대한금속재료학회(대한금속학회) 1998 METALS AND MATERIALS International Vol.4 No.4

The thermal physical properties were treated as a functions of temperature. On the basis of non-linear surface heat-transfer coefficient by Ref. [2], the temperature field with non-linear surface heat-transfer coefficients was calculated using finite clement technique. The experimental results of temperature field coincide with numeral solutions. Finally, the thermal stress was calculated by means of finite element method.