Agile Networking in Smart Grids

Qin, Zhenquan,Zhang, Jianing,Shi, Liang,Wang, Lei,Shu, Lei,Guo, Yuquan The Institute of Electronics and Information Engin 2012 IEIE Transactions on Smart Processing & Computing Vol.1 No.1

Recently, the smart grid (SG) has been introduced to solve the serious network issues caused by the increasing electrical demand and the complex nonlinear nature of the electric power distribution network. The SG, regarded as the next generation power grid, can transmit power in more efficient ways by building an automatic and distributed energy delivery network. In this paper, we first assess how various existing networking technologies, such as IEEE 802.11 (WiFi) and IEEE 802.15.4 (ZigBee), meet the requirements of the SG communication protocols. Specifically, we classify the existing network protocols into three categories: WSN-based networking, WiFi-based networking, and wireline-based networking. We then survey the security issues regarding the SG. Finally, we propose an agile SG networking architecture and show the effectiveness of different adopted networking technologies and, as a result, present a candidate solution to implement agile networking in SGs.

An I-V Circuit with Combined Compensation for Infrared Receiver Chip

Lei Tian,Qin-qin Li,Shu-juan Chang 대한전기학회 2018 Journal of Electrical Engineering & Technology Vol.13 No.2

This paper proposes a novel combined compensation structure in the infrared receiver chip. For the infrared communication chip, the current-voltage (I-V) convert circuit is crucial and important. The circuit is composed by the transimpedance amplifier (TIA) and the combined compensation structures. The TIA converts the incited photons into photocurrent. In order to amplify the photocurrent and avoid the saturation, the TIA uses the combined compensation circuit. This novel compensation structure has the low frequency compensation and high frequency compensation circuit. The low frequency compensation circuit rejects the low frequency photocurrent in the ambient light preventing the saturation. The high frequency compensation circuit raises the high frequency input impedance preserving the sensitivity to the signal of interest. This circuit was implemented in a 0.6μm BiCMOS process. Simulation of the proposed circuit is carried out in the Cadence software, with the 3V power supply, it achieves a low frequency photocurrent rejection and the gain keeps 109dB ranging from 10nA to 300μA. The test result fits the simulation and all the results exploit the validity of the circuit.

Wave propagation of graphene platelets reinforced metal foams circular plates

Lei-Lei Gan,Jia-Qin Xu,Gui-Lin She 국제구조공학회 2023 Structural Engineering and Mechanics, An Int'l Jou Vol.85 No.5

Based on first-order shear deformation theory, a wave propagation model of graphene platelets reinforced metal foams (GPLRMFs) circular plates is built in this paper. The expressions of phase-/group- velocities and wave number are obtained by using Laplace integral transformation and Hankel integral transformation. The effects of GPLs pattern, foams distribution, GPLs weight fraction and foam coefficient on the phase and group velocity of GPLRMFs circular plates are discussed in detail. It can be inferred that GPLs distribution have great impacts on the wave propagation problems, and Porosity- I type distribution has the largest phase velocity and group velocity, followed by Porosity-III, and finally Porosity-II; With the increase of the GPLs weight fraction, the phase- and group- velocities for the GPLRMFs circular plate will be increased; With the increase of the foam coefficient, the phase- and group- velocities for the GPLRMFs circular plate will be decreased.

Analysis on an improved resistance tuning type multi-frequency piezoelectric spherical transducer

Lei Qin,Jianjun Wang,Donghuan Liu,Lihua Tang,Gangbing Song 국제구조공학회 2019 Smart Structures and Systems, An International Jou Vol.24 No.4

The existing piezoelectric spherical transducers with fixed prescribed dynamic characteristics limit their application in scenarios with multi-frequency or frequency variation requirement. To address this issue, this work proposes an improved design of piezoelectric spherical transducers using the resistance tuning method. Two piezoceramic shells are the functional elements with one for actuation and the other for tuning through the variation of load resistance. The theoretical model of the proposed design is given based on our previous work. The effects of the resistance, the middle surface radius and the thickness of the epoxy adhesive layer on the dynamic characteristics of the transducer are explored by numerical analysis. The numerical results show that the multi-frequency characteristics of the transducer can be obtained by tuning the resistance, and its electromechanical coupling coefficient can be optimized by a matching resistance. The proposed design and derived theoretical solution are validated by comparing with the literature given special examples as well as an experimental study. The present study demonstrates the feasibility of using the proposed design to realize the multi-frequency characteristics, which is helpful to improve the performance of piezoelectric spherical transducers used in underwater acoustic detection, hydrophones, and the spherical smart aggregate (SSA) used in civil structural health monitoring, enhancing their operation at the multiple working frequencies to meet different application requirements.

Research of the adaptive control on modulation factor for PSR fly‐back PSM converter

Lei Tian,Qin-qin Li,Weiheng Wang 한국전자통신연구원 2019 ETRI Journal Vol.41 No.1

The energy balance (EB) model of a primary side regulation (PSR) fly‐back converter in the discontinuous conduction mode (DCM) is discussed in this paper. Based on this EB model, the stability of a PSR fly‐back converter in the pulse skipping mode (PSM) is analyzed, and a self‐adapting modulation factor control strategy is proposed. Theoretical analysis and simulation results show that by saving an optocoupler and correlative circuits, which are necessary in traditional PSM fly‐back converters, the modulation factor tolerance controlled by this method is 1.26% on average, corresponding to the ideal value. Compared with traditional fly‐back PSM controllers, the power saved in the sampler/comparator modules is 87% on average for a load range of 1 Ω to 1 kΩ.

Sol–gel preparation, band structure, and photochemical activities of double perovskite <i>A</i> ₂NiWO₆ (<i>A</i> =Ca, Sr) nanorods

Xu, Lei,Qin, Chuanxiang,Wan, Yingpeng,Xie, Hongde,Huang, Yanlin,Qin, Lin,Seo, Hyo Jin Elsevier 2017 JOURNAL- TAIWAN INSTITUTE OF CHEMICAL ENGINEERS Vol.71 No.-

<P><B>Abstract</B></P> <P> <I>A</I> <SUB>2</SUB>NiWO<SUB>6</SUB> (<I>A</I> =Ca, Sr) double perovskite semiconductors were prepared via the sol–gel method. The crystal phases were confirmed via X-ray powder diffraction (XRD) measurements together with Rietveld refinements. The morphological and chemical properties of the samples were investigated by the scanning electron microscope (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), and the specific surface area measurements. The optical absorptions and the band structures of the two double perovskites were discussed based on the on the experimental results and theoretical calculation. The d–d allowed transitions in Ni<SUP>2</SUP> <SUP>+</SUP>–O octahedra have great contributions to the narrow band-gap. The Ni<SUP>2+</SUP>-containing tungstate perovskites were potential photocatalysts, which are efficient for its photodegradation for methylene blue (MB) under the irradiation of visible light (λ<ce:italic/>> 420nm). The photocatalytic activities were attributed to the special structure properties and multivalent Ni and W ions in the perovskite lattices.</P> <P><B>Highlights</B></P> <P> <UL> <LI> <I>A</I> <SUB>2</SUB>NiWO<SUB>6</SUB> (<I>A</I> =Ca, Sr) nano-perovskite were prepared via the sol–gel method. </LI> <LI> The crystalline crystal structure was refined. </LI> <LI> The optical absorption and band structure were clarified. </LI> <LI> The photocatalysis activities were discussed on structural properties. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

An I-V Circuit with Combined Compensation for Infrared Receiver Chip

Tian, Lei,Li, Qin-qin,Chang, Shu-juan The Korean Institute of Electrical Engineers 2018 Journal of Electrical Engineering & Technology Vol.13 No.2

This paper proposes a novel combined compensation structure in the infrared receiver chip. For the infrared communication chip, the current-voltage (I-V) convert circuit is crucial and important. The circuit is composed by the transimpedance amplifier (TIA) and the combined compensation structures. The TIA converts the incited photons into photocurrent. In order to amplify the photocurrent and avoid the saturation, the TIA uses the combined compensation circuit. This novel compensation structure has the low frequency compensation and high frequency compensation circuit. The low frequency compensation circuit rejects the low frequency photocurrent in the ambient light preventing the saturation. The high frequency compensation circuit raises the high frequency input impedance preserving the sensitivity to the signal of interest. This circuit was implemented in a $0.6{\mu}m$ BiCMOS process. Simulation of the proposed circuit is carried out in the Cadence software, with the 3V power supply, it achieves a low frequency photocurrent rejection and the gain keeps 109dB ranging from 10nA to $300{\mu}A$. The test result fits the simulation and all the results exploit the validity of the circuit.

A 3-D Steady-State Analysis of Thermal Behavior in EHV GIS Busbar

Lei, Jin,Zhong, Jian-ying,Wu, Shi-jin,Wang, Zhen,Guo, Yu-jing,Qin, Xin-yan The Korean Institute of Electrical Engineers 2016 Journal of Electrical Engineering & Technology Vol.11 No.3

Busbar has been used as electric conductor within extra high voltage (EHV) gas insulated switchgear (GIS), which makes EHV GIS higher security, smaller size and lower cost. However, the main fault of GIS is overheating of busbar connection parts, circuit breaker and isolating switch contact parts, which has been already restricting development of GIS to a large extent. In this study, a coupled magneto-flow-thermal analysis is used to investigate the thermal properties of GIS busbar in steady-state. A three-dimensional (3-D) finite element model (FEM) is built to calculate multiphysics fields including electromagnetic field, flow field and thermal field in steady-state. The influences of current on the magnetic flux density, flow velocity and heat distribution has been investigated. Temperature differences of inner wall and outer wall are investigated for busbar tank and conducting rod. Considering the end effect in the busbar, temperature rise difference is compared between end sections and the middle section. In order to obtain better heat dissipation effect, diameters of conductor and tank are optimized based on temperature rise simulation results. Temperature rise tests have been done to validate the 3-D simulation model, which is observed a good correlation with the simulation results. This study provides technical support for optimized structure of the EHV GIS busbar.

Thermo-sensitive Amphiphilic Block Copolymer Poly (styrene-b-Nisopropylacrylamide) with Switchable Catalytic Activity Immobilizing Pectinase

Qin Jiang,Zhongli Lei 한국생물공학회 2011 Biotechnology and Bioprocess Engineering Vol.16 No.6

Pectinase was immobilized onto thermo-sensitive amphiphilic block copolymers poly(styrene-b-Nisopropylacrylamide)PS-b-poly(N-isopropylacrylamide)(PNIPAM) by covalent attachment. Biochemical studies have found that the stability of the PS-b-PNIPAM support is not impeded by the bound proteins despite that up to 242.5 mg of enzyme is immobilized per gram of carrier particles. The immobilized enzyme retained nearly 65% of its initial activity over 30 days, and the optimum temperature and pH also increased to the range of 60 ~ 70°C and 4.0 ~ 6.0, respectively. The immobilized enzyme also exhibited great operational stability, and more than 60%residual activity was observed in the immobilized enzyme after 10 batch reactions. Moreover, the lower critical solution temperature of the PS-b-PNIPAM support could be switched on or off by a small change in solution temperature. Thus, the immobilized pectinase could be recovered and showed durable activity during the recycle process.

Optimized Charging in Large-Scale Deployed WSNs with Mobile Charger

Qin, Zhenquan,Lu, Bingxian,Zhu, Ming,Sun, Liang,Shu, Lei Korean Society for Internet Information 2016 KSII Transactions on Internet and Information Syst Vol.10 No.12

Restricted by finite battery energy, traditional wireless sensor networks (WSNs) can only maintain for a limited period of time, resulting in serious performance bottleneck in long-term deployment of WSN. Fortunately, the advancement in the wireless energy transfer technology provides a potential to free WSNs from limited energy supply and remain perpetual operational. A mobile charger called wireless charging vehicle (WCV) is employed to periodically charge each sensor node and keep its energy level above the minimum threshold. Aiming at maximizing the ratio of the WCV's vocation time over the cycle time as well as guaranteeing the perpetual operation of networks, we propose a feasible and optimal solution to this issue within the context of a real-time large-scale deployed WSN. First, we develop two different types of charging cycles: initialization cycles and renewable cycles and give relevant algorithms to construct these two cycles for each sensor node. We then formulate the optimization problem into an optimal construction algorithm and prove its correctness through theoretical analysis. Finally, we conduct extensive simulations to demonstrate the effectiveness of our proposed algorithms.