Controlled-Type ZVS Technique without Auxiliary Components for Micro-inverters

Zhang, Qian,Zhang, Dehua,Hu, Haibing,Shen, John,Batarseh, Issa The Korean Institute of Power Electronics 2013 JOURNAL OF POWER ELECTRONICS Vol.13 No.6

This paper proposes a Boundary Current Mode (BCM) control scheme to realize soft switching on a conventional single phase full bridge DC/AC inverter. This technique with the advantages of no auxiliary components, low cost, high efficiency, and simple in control, is attractive for micro-inverter applications. The operation principle and characteristic waveforms of the proposed soft switching technique are analyzed in theory. A digital controller is provided based on that theory. To balance the requirements of efficiency, switching frequency, and inductor size, the design considerations are discussed in detail to guide in BCM inverter construction. A 150W prototype is built under these guidelines to implement the BCM control scheme. Simulation and experiment results demonstrate the feasibilities of the proposed soft switching technique.

Guaranteeing Deadlines for Inter-Data Center Transfers

Zhang, Hong,Chen, Kai,Bai, Wei,Han, Dongsu,Tian, Chen,Wang, Hao,Guan, Haibing,Zhang, Ming Institute of Electrical and Electronics Engineers, 2017 IEEE/ACM transactions on networking Vol.25 No.1

<P>Inter-data center wide area networks (inter-DC WANs) carry a significant amount of data transfers that require to be completed within certain time periods, or deadlines. However, very little work has been done to guarantee such deadlines. The crux is that the current inter-DC WAN lacks an interface for users to specify their transfer deadlines and a mechanism for provider to ensure the completion while maintaining high WAN utilization. In this paper, we address the problem by introducing a deadline-based network abstraction (DNA) for inter-DC WANs. DNA allows users to explicitly specify the amount of data to be delivered and the deadline by which it has to be completed. The malleability of DNA provides flexibility in resource allocation. Based on this, we develop a system called Amoeba that implements DNA. Our simulations and test bed experiments show that Amoeba, by harnessing DNA's malleability, accommodates 15% more user requests with deadlines, while achieving 60% higher WAN utilization than prior solutions.</P>

Controlled-Type ZVS Technique without Auxiliary Components for Micro-inverters

Qian Zhang,Dehua Zhang,Haibing Hu,John Shen,Issa Batarseh 전력전자학회 2013 JOURNAL OF POWER ELECTRONICS Vol.13 No.6

This paper proposes a Boundary Current Mode (BCM) control scheme to realize soft switching on a conventional single phase full bridge DC/AC inverter. This technique with the advantages of no auxiliary components, low cost, high efficiency, and simple in control, is attractive for micro-inverter applications. The operation principle and characteristic waveforms of the proposed soft switching technique are analyzed in theory. A digital controller is provided based on that theory. To balance the requirements of efficiency, switching frequency, and inductor size, the design considerations are discussed in detail to guide in BCM inverter construction. A 150W prototype is built under these guidelines to implement the BCM control scheme. Simulation and experiment results demonstrate the feasibilities of the proposed soft switching technique.

Influence of different electrical boundary conditions on the elasticity solutions of piezoelectric plane beam

Zhang Lang,Li Xuewu,Wang Yuping,Wang Qiang,Shi Haibing 대한기계학회 2013 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.27 No.12

Influence of different electrical boundary conditions (BCs) on the elasticity solutions of piezoelectric plane beam (PPB) is investigated using analytical technique. The first case is considering electrical displacement of the two longitudinal sides of PPB. The second case is electrical potential. Firstly, the unified equations to obtain the elasticity solutions of PPB corresponding to these two cases are given briefly. Secondly, two examples are given to verify the correctness of the theoretical formulations presented in this paper. Finally, the responses of PPB acted by the same mechanical loads but with different electrical BCs are compared.

High-efficiency technique for five-axis side milling of niemann worm wheels

Haibing Wu,Zheng Zhang,Quanping Sun 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.6

Five-axis side milling technique for Niemann worm wheel teeth flank using a tapered flat-end mill is presented. Equations describing the worm wheel tooth flank were derived based on differential geometry and the working principle of gears. The tooth flank was modified by offsetting its point cloud computed using these equations along the normal direction. The maximum normal curvature of the worm wheel tooth flank was computed, and its minimum radius of curvature was obtained. The cutter path step length and spacing between cutter travels were computed to generate a uniform path for five-axis machining. Software simulations of the cutter path were performed for validation and for analysing errors in the worm wheel tooth flank machining; this technique was also verified by milling worm wheels. The results demonstrated that the technique not only improved machining efficiency by 5 times compared with point milling but also guaranteed precision machining of the tooth flank for five-axis machining of cylindrical worm drives.

Hybrid Topology with Reconfigurable Rectifier for Enable CC and CV Output Characteristics in Wireless Power Transfer Systems

Haibing Wen,Jiayuan Li,Jiadong Yang,Peng Wang,Ke-Han Zhang,Lei Yang,Yaopeng Zhao,Xiangqian Tong 한국전자파학회 2024 Journal of Electromagnetic Engineering and Science Vol.24 No.3

To achieve simple and reliable conversion from constant current (CC) charging mode to constant voltage (CV) charging mode in wireless power transfer systems, this paper proposes a hybrid topology equipped with a reconfigurable rectifier. An AC switch is adapted to simul- taneously realize the change from half-bridge rectification to full-bridge rectification and achieve the shift from a topology with capacitors in the series compensated primary and secondary sides to a topology with capacitors in the series compensated primary side and the induc- tor-capacitor-inductor (LCL) compensated secondary side. Notably, communication between the transmitter and receiver sides is not necessary in the proposed method. Furthermore, the zero phase angle characteristic is successfully maintained in both charging modes. The experimental results obtained using the 48 V/0.7 A experimental prototype, which was built to validate the relevant theoretical analy- sis, show that output current/voltage can be achieved in CC/CV charging mode independent of load resistance. Notably, the maximum power transfer efficiency of the system during the charging process reached 95.33%.

Selective molecular recognition on calixarene-functionalized 3D surfaces

Zhang, Fan,Sun, Yue,Tian, Demei,Shin, Weon Sup,Kim, Jong Seung,Li, Haibing The Royal Society of Chemistry 2016 Chemical communications Vol.52 No.86

<P>Host-guest recognition plays an important role in biological analysis and biosensing. Accordingly, great efforts have been devoted to the development of sensors using versatile 3D surface materials. These functionalized nanomaterials possess the advantages of high selectivity and visual signals, enabling the selective detection of ions, amino acids, proteins, and other biological molecules. Therefore, in this feature article, we present some significant and representative examples of molecular recognition on calixarene functionalized 3D surface nanomaterials. By virtue of host-guest interactions, the functional interfaces displaying high selectivity and featuring a reversible switch response towards the environmental stimuli with various signal output (electrochemical and optical signals) are herein introduced. Furthermore, various 3D surface materials with unique signal amplification in molecular recognition are presented, including quantum dots (QDs), metal nanoparticles (NPs), nanotubes, and mesoporous silica. These excellent properties enable calixarene-functionalized 3D materials to become an outstanding platform for molecular recognition, offering convenient approaches for sensing and separation.</P>

Accuracy analysis of generalized discrete Fourier transform‑based harmonics extraction in presence of background harmonics

Shuo Zhang,Yuzheng Xia,Tao Yang,Xiang Li,Daorong Lu,Haibing Hu 전력전자학회 2022 JOURNAL OF POWER ELECTRONICS Vol.22 No.1

The generalized discrete Fourier transform (GDFT) realizes the rapid extraction of specific order harmonics, and shortens the extraction time to 1/3 of a fundamental cycle (6.7 ms at 50 Hz grid) for 6r ± 1 order harmonics. However, the GDFT becomes less accurate when the system presents background harmonics other than specific-order harmonics in the inputs. Therefore, this paper analyzes the influence introduced by these background harmonics on the GDFT. First, the frequency feature of the GDFT is derived by a geometric method based on the z-domain unit circle. Then, the extraction of the 6r ± 1 order harmonics is taken as an example to show the extraction accuracy of the GDFT. The Accuracy of Harmonic Extraction (AHE) index, is also given to evaluate the accuracy of the extraction. Simulation and experimental results confirmed the correctness of the theoretical analysis by showing that the GDFT has the same accuracy as the RDFT when only 6r ± 1 order harmonics are involved. However, if there are other background harmonics in the inputs, the extraction accuracy is affected greatly. Therefore, when the background harmonics cannot be ignored, it is necessary to analyze the AHE of the GDFT. When AHE > 95%, the GDFT has good accuracy and is applicable to real applications.

Study on the Mechanical Properties and Microstructure of Geogrid Under Different Materials and Temperatures

Junli Gao,Haibing Zhang,Xuelei Xie,Yapo Zhang 한국섬유공학회 2022 Fibers and polymers Vol.23 No.6

In response to the environmental problems caused by the difficulty of direct degradation of the raw materials usedin traditional geogrids and the impact of different temperatures on the mechanical properties of geogrids in practicalengineering applications, based on 3D printing technology, polylactic acid (PLA), carbon fiber reinforced polylactic acid(PLA/CF), and thermoplastic polyurethane (TPU) geogrids were fabricated. The 3D printed geogrids and the fiberglassgeogrids used in the actual project were tested in indoor tensile tests under different temperature conditions. The mechanicalproperties of the geogrids of the four kinds of materials and six kinds of temperature were analyzed. The microstructure of thegeogrids after tensile tests was investigated based on scanning electron microscopy technology to further analyze the effectsof different materials and temperatures on the mechanical properties of the geogrids. The results showed that the tensilestrength of PLA/CF geogrids and PLA geogrids decreased with increasing temperature. The tensile strength of fiberglassgeogrids increased with rising temperatures. The tensile strength of PLA/CF geogrids was significantly better than PLAgeogrids. Due to the addition of carbon fiber in PLA, PLA/CF can bear more tensile force at high temperatures. With theincrease of temperature, the elongation at break of PLA/CF geogrids and fiberglass geogrids increased, but the elongation atbreak of PLA geogrids decreased. The elongation at break of PLA/CF geogrids was significantly lower than that of PLAgeogrids. TPU geogrids had high tensile capacity in a high-temperature environment, and they also had high elasticity andmore significant elongation at break, which was not suitable to be used as geogrid material.

Influence of the Billet Volume Distribution on Macro Deformation and Microstructure Response in Transitional Region of Ti-Alloy Multi-rib Component Under Isothermal Local Loading

Ke Wei,Qing Ma,Haibing Tang,Xiaoguang Fan,Jian Zhang 한국정밀공학회 2021 International Journal of Precision Engineering and Vol.22 No.12

The folding, die underfilling, rib shifting and average grain size of primary equiaxed were investigated using five different unequal thickness billets in transitional region of Ti-alloy multi-rib component under isothermal local loading and compared with integral loading. In terms of the macro deformation, the results show that the material transfers from the second-loading zone into the first-loading zone and the die underfilling decreases with the initial volume of the first-loading zone increasing, which reduces the risk of folding and rib shifting. However, that folding and rib shifting did not appear during the integral loading. Nevertheless, when the initial volume of the first-loading zone reaches a certain value, the die underfilling is aggravated both in local and integral loading. With respect to the microstructure, as the initial volume of the first-loading zone increases, the average grain size is decreased after the first-loading step, but increased after the second-loading step with consideration of one single loading step, which lead to the grain size being barely influenced by different billet volume distribution under both loading steps.