Zhejiang University - Gunma University International Summer School of Graduate Students,
Zhejiang University
Time
September 17, 2018
Venue
Room 405, No 2 Teaching Building, Yuquan Campus, Zhejiang University
Program Committee
Prof. Hiroshi Sakurai (Gunma University, Japan)
Prof. Jianxin Shen (Zhejiang University, China)
Prof. Hayato Sone (Gunma University, Japan)
Prof. Tao Wang (Zhejiang University, China)
Prof. You Yin (Gunma University, Japan)
IWAEEE 2018 Focus Topics
The International Workshop on Advanced Electrical and Electronic Engineering 2018 (IWAEEE2018) covers the following topics:
? Artificial Intelligence (Materials, Device, Circuits & System)
? Internet of Things (Circuits & System)
? Sensors
? Nonvolatile memories
? Advanced electronic materials
? Physics in electronics
? Advanced semiconductor
? Circuits
? Communications
Program
Welcome address
Session 1
(13:00 - 13:20) (Invited) Prof. Hiroshi Sakurai (Gunma University, Japan)
Applications of Compton scattering to material science and imaging
Coauthors: Hiroshi Sakurai and Kosuke Suzuki
Abstract: The Compton effects are well known as the experimental evidence of particle-like behavior of light. A. H. Compton proved that “a photon directed momentum, hν/c, as well as energy hν” from the Compton scattering experiments. However, Compton scattering can also probe wave functions of electrons in materials, in other words, chemical bonding. Furthermore, we can get non-destructive images of light elements using Compton scattering with high energy X-rays. In this study we talk about our recent studies of electronic structure of Li ion battery (LIB) materials (LiMn2O4, LiCoO2 and LiFePO4). Furthermore, we talk about non-destructive images of Li ions in an LIB.
(13:20 - 13:40) (Invited) Prof. Tao Wang (Zhejiang University, China)
Some topics in nano electronics
Abstract: IC is really the nano technology, since chip critical size is 90nm about ten year ago. Some topics about devices are ongoing till now and 3 interesting study are presented today. The one method of Si nanowire fabrication is introduced and its gate-all-around devices are shown together. The graphene/Cu interface is another meaningful interface, which was investigated by experiments and simulation. The light current at different nano wire and tube and 2D films are compared in the terms of theory.
(13:40 - 14:00) (Invited) Prof. You Yin (Gunma University, Japan)
Ultralow-Volume- Change Phase-Change Materials and High-Performance Memory Devices for IoT Application
Abstract: In this talk, phase-change materials and memory devices for internet of everything (IoT) application will be discussed. For better reliability and retention, doping N into GeTe with a fast operation speed was investigated with the aim of reducing the volume change upon crystallization. For high-density, the multilevel storage was investigated using SbTeN-based devices and several resistance levels with good stability were demonstrated, which resulted mainly from the gradual enlargement of crystalline region between electrodes by Joule heating. For low power consumption, phase-change memory (PCM) incorporated with nanostructures was investigated and was proved to be very energy-efficient.
(14:00 - 14:15) Mr. Yi Sun (Zhejiang University, China),
Active Saturation Method for Rotor Magnetic Bridges in Synchronous Reluctance Machines
Abstract: Synchronous reluctance machine, permanent magnet assisted synchronous reluctance machine, and interior permanent magnet synchronous machine share the same kind of rotor topology. Comprehensive investigations on the correlation between the amount and function of the permanent magnets buried in the rotor have been carried out to reveal the intricate relationship of these machine types. Both circumferential and radial ?ux bridges are commonly employed to provide dependable rotor integrity in these machines. However, the ?ux bridge width has a tremendous bearing on both electromagnetic performance and mechanical ruggedness, especially for synchronous reluctance machine. In this paper, the active saturation method is hence applied in synchronous reluctance machine to strike the right balance between manufacturability and electromagnetic performance. A 5kW@3000rpm synchronous reluctance machine with ?ux bridge width of 1mm has been optimized to realise the active saturation method. Moreover, the in?uence of permanent magnet location patterns on the active saturation method has been investigated in detail.
(14:15- 14:30) Mr. A. Terasaka (Gunma University, Japan)
Measurement of non-destructive Li reaction distribution of deteriorated battery using Compton scattering method
Coauthors: A.Terasaka, K. Suzuki*, D.Hiramoto N. Tsuji, Y. Orikasa, Y. Uchimoto, Y. Sakurai and H. Sakurai
Abstract: We have developed in-operando technique for the lithium-ion batteries using high-energy X-ray Compton scattering. The Compton scattering is experimental technique to measure momentum density distribution of the electrons. Advantages of this technique are a usage of high-energy X-rays, over 100 keV, as incident beam and the line-shape of Compton scattered X-ray energy spectrum, so-called Compton profile, depend on the elements. The high-energy X-rays which have high-penetration power permit us to measure the reaction in closed electrochemical cells in operando condition. The line-shape of Compton scattered energy spectrum enable us to quantitate Li concentration which contributed charge-discharge process. In this study, we applied this technique to a commercial coin cell lithium-ion battery, VL2020 and Li reaction distribution of SOC 0 and SOC 100 was measured using flesh and fade batteries. In flesh battery, Li reaction accompanying charge and discharge was observed. Fade battery did not respond to charge / discharge. Instead, it is predicted that there is a new structure at the separator-positive electrode interface. We also found that the negative electrode expands.
(14: 30- 14:45) Mr. Siyang Sun (Zhejiang University, China)
Optimal Temporal-spatial Electric Vehicle Charging Demand Scheduling Considering Transportation-Power Grid Couplings
Abstract: This paper proposed a holistic temporal-spatial scheduling approach for charging demand (both fast charging and normal charging) of plug-in electric vehicles (PEVs). The proposed solution aims to optimally schedule the PEV charging actions based on PEV operational states with minimized charging costs and travel time, whilst meets the constraints of both transportation and power distribution networks. The power utility can also participate in the scheduling strategy by adopting real-time pricing (RTP) to increase the utilization efficiency of distributed generation (DG) and optimize the profiles of power distribution networks. The proposed solution was assessed through a set of case studies and the numerical results clearly demonstrated the effectiveness of the proposed strategy.
(14:45- 15:00) Mr. K. Haishi (Gunma University, Japan)
Magnetization switching behavior for CoFeB/MgO and CoFeB/Ta multilayer films,
Coauthors: K. Haishi, A. Shibayama, M. Adachi, H. Sakurai, K. Suzuki, K. Hoshi, M. Yamazoe, M. Itou, N. Tsuji and Y. Sakurai
Abstract: Recently, Ta/CoFeB/MgO/CoFeB/Ta magnetic tunneling junction (MTJ) films with perpendicular magnetic anisotropy (PMA) are interesting because PMA can reduce the critical current for current-induced magnetization switching. It was reported that the PMA comes from the MTJ interface of the films. Therefore magnetization switching of the MTJ interface is a key characteristic of a spintronic device.
Magnetic Compton profile (MCP) measurement can probe the spin selective magnetization. In this paper, we report magnetization switching behavior of the spin selective magnetic hysteresis (SSMH) curves, orbital selective magnetic hysteresis (OSMH) curves for CoFeB/MgO and CoFeB/Ta multilayer films from the view-point of the magnetization switching behavior with the PMA.
The SSMH curves of the CoFeB/MgO and CoFeB/Ta multilayer films show magnetic shape anisotropy of an in-plane magnetic anisotropy. However, the OSMH curves of the CoFeB/MgO and CoFeB/Ta multilayer films show a step-function-like behavior with rather small magnetization switching fields as if they possess PMA.
Break (15 minutes)
Session 2
(15:15- 15:30) Mr. Hao Li (Zhejiang University, China)
Maximum-Efficiency Operation of a 3.7 kW Inductive Wireless Charging System by Using OnOff Keying Modulation
Abstract: The efficiency of an inductive wireless charging system varies in a large range as the load resistance changes in the charging process. Thus, maximum-efficiency operation is a basic requirement. A few methods to achieve maximumefficiency operation have been proposed, including using a dcdc stage, using impedance transformation circuits, using primary-side on-off keying modulation etc. In this paper, the significance of maximum-efficiency-operation techniques is firstly addressed. Then, a study is carried out on the system with on-off keying modulation which is reported as the simplest approach to achieve maximum-efficiency operation without using any extra components. The required output capacitance of the system with on-off keying is analyzed and compared with that of the system with phase-shift control. The efficiencies are measured based on a practical wireless charging system and the total energy saving is calculated with respect to the energy consumption of the system with phaseshift control.
(15: 30- 15:45) Mr. K. Oshima (Gunma University, Japan)
Fabrication of N-type Silicon Nanowire Biosensor for Sub-10-Femtomolar Concentration of Immunoglobulin
Coauthors: Tomoya Tashiro, Hui Zhang, Kakeru Oshima, Yuya Sakurai, Takaaki Suzuki, Noriyasu Ohshima, Takashi Izumi, Hayato Sone
Abstract: A simple fabrication process of an n-type silicon nanowire (SiNW) biosensor for sub-10 femtomolar (fM) concentration immunoglobulin detection was presented in this work. The SiNWs with different widths of 80-190 nm were fabricated using electron beam lithography and reaction ion etching techniques. The electrical characteristics of SiNWs with various widths were measured. And it can be observed that thin SiNW has high resistance, which is in agreement with electrical resistance theory. Furthermore, the surface of the fabricated SiNW was functionalized by 3-aminopropyltriethoxysilane for making the biosensor device to detect the binding of immunoglobulin G (IgG) molecules. The responsivity of the biosensor was investigated by observing electrical performance in response due to IgG with various concentration from 6 fM to 600 nanomolar (nM). The resistance changing ratio based on the current voltage (I-V) characteristics was analyzed and it increased with increasing of the IgG concentration. As a result, it demonstrated that the n-type SiNW biosensor has the ability to detect the IgG molecules with low concentration of 6 fM.
(15:45- 16:00) Ms. Linbin Huang (Zhejiang University, China)
An Adaptive Phase-Locked Loop to Improve Stability of Voltage Source Converters in Weak Grids
Abstract: Three-phase voltage source converters (VSCs) usually utilize phase-locked loop (PLL) to realize grid synchronization. However, when the VSC is connected to weak grids featured by high grid impedances, its dynamics will be deteriorated if a conventional fixed-gain PLL is used, which can even lead to grid-synchronization instability of the VSC. To deal with this problem, an adaptive phase-locked loop (AdPLL) is proposed in this paper, which ensures that the VSC has an expected stability margin in weak grids by adaptively regulating the AdPLL’s control bandwidth according to the identified grid impedance. The grid impedance is identified in real time along the system trajectory, in which the recursive least square method is applied to reduce its computation burden and enable its implementation in the VSC controller. Simulation results verify the effectiveness of the AdPLL on improving the VSC’s stability in weak grids.
(16:00 - 16:15) Mr. T. kato (Gunma University, Japan)
Formation of W Nanowire Using Electron Beam Lithography and Its Application to Highly Sensitive Gas Sensor
Coauthors: Takumi Kato, Naoki Sakuma, and Hayato Sone
Abstract: Gas sensors have a wide range of applications, especially have a role of preventing accidents caused by leakage of combustible gas. In this research, we aimed to form W nanowires using electron beam lithography, and to fabricate high-sensitivity and low-power gas sensor. It is a principle that combustible gases are detected by resistance change of the nanowires due to redox reaction on the nanowire surface by combustible gas.
We formed W film with a thickness of 45 nm using a rotating tray type DC sputtering apparatus. W nanowire sensor was fabricated by electron beam drawing and reactive ion etching. We confirmed that the nanowires were formed between two W electrode with a width of 84 nm to 259 nm using scanning electron microscope and height of 18.5 nm using atomic force microscope. Then, we measured the nanowire resistivity of 1.2 × 10-4 Ω· cm by current-voltage measurement system. As this value is slightly larger than the W resistivity, it is possible that the nanowire surface is oxidized. We are planning to detect combustible gas using fabricated sensor in future work.
(16:15- 16:30) Mr. Lei Ji (Zhejiang University, China)
An Optimized Control Strategy to Improve the Current Zero-Crossing Distortion in Bidirectional AC/DC Converter based on V2G Concept
Abstract: With the development of smart grid and new energy technology, V2G (vehicle-to-grid) has become a new research hotspot, and bidirectional converter plays an important role in it. In this paper, a bidirectional AC/DC converter using SiC device is developed, and unipolar PWM modulation is adopted in consideration of efficiency.
Compared with other modulation methods that are widely used, unipolar modulation has the advantages of low switching loss, small current ripple and small common mode noise, however the current is distorted at zero-crossing. With the investigation on the characteristics of the current zero-crossing distortion based on the AC/DC converter prototype, an optimized control strategy which generates the switching signal for the line frequency bridge based on the control loop output reference (CLOR) instead of the grid voltage is proposed. The performance of the analyses and the proposed strategy is verified by experiments.
(16: 30- 16:45) Mr. T. Wakahara (Gunma University, Japan)
Fabrication of Fluorescence Detection Optical System to Develop Scanning Near-Field Fluorescence Microscope
Coauthors: Takahiro Wakahara, Masayuki Ono, Sumio Hosaka, and Hayato Sone
Abstract: An observation technique of surface characteristics on biomaterials with highly resolution is desired in the field of biotechnology and medical science. In our laboratory, scanning near-filed optical microscope (SNOM) has been developed using atomic force microscope (AFM) system. In this research, we fabricated a fluorescence detection optical system to develop a scanning near-field fluorescence microscope for observation of fluorescent labeled biomaterials.
Firstly, we calculated the trancemittance of near-field light from an aperture which open the end of a metal coated probe tip using finite-difference time-domain (FDTD) method. The transmittance of 1.56% was obtained by the simulation result for the silver coated probe tip with the aperture diameter of 200 nm. Secondly, we exchanged mirrors in the microscope to apply the fluorescence light of blue laser as excitation source. As the result, the transmittance of the blue laser power was increased about 1.5 times larger than that before exchanging. Finery, we fabricated a metal thin film coated cantilever on a tip side, and tried to form a small aperture on the end of the tip by scratching method using contact mode AFM. We will evaluate the fluorescence image by the cantilever tip using scanning near-filed fluorescence microscope in future work.
(16:45- 17:00) Mr. Lei Yang (Zhejiang University, China)
Robust Current Control Method for LCL-Type Shunt Active Power Filters with Inverter-Side Current Feedback Active Damping
Abstract: This paper has presented a current control method for LCL-type shunt active power filters (APF), which has good robustness against grid impedance variation. In the current control method, the grid current is measured to implement grid harmonic closed-loop regulation, and the inverter-side current feedback active damping (AD) is adopted to attenuate the LCL-filter resonance. For the inverter-side current feedback AD, a repetitive control link is introduced to replace the common proportional feedback link, which can extend the valid damping region for LCL resonance frequency up to one-fourth of the sampling frequency (fs/4) and improve the system robustness to grid impedance. Then, the optimal damping coefficient of the repetitive link is obtained by the root locus of AD inner loop. Meanwhile, considering that the control plant exists the obvious phase delay at the higher harmonic orders, the resonant controller with phase angle compensation is introduced to constitute the current controller and avoid the harmonic amplification. Finally, experimental results on a 30kVA APF prototype have validated the robustness of the proposed current control method.
(17:00 - 17:15) Mr. Y. Kobayashi (Gunma University, Japan)
Development of spectral CT system using CdTe detector
Coauthors: Yuki Kobayashi, Daiki Ono, Yosuke Harasawa, Akie Nagao, Naoki Sunaguchi, Kosuke Suzuki, Kazushi Hoshi, Masami Torikoshi and Hiroshi Sakurai
Abstract: Recently obtain electron density and atomic number measurements were reported by using spectral CT system. This method can be used for various purposes such as medical diagnosis and explosive detection. They used an energy selective multi-channel type line sensor. However, its accuracy is not enough especially for medical application. This can be ascribed to the variation of the each detector in the multi-channel type line sensor. Therefore, we suggest a single detector system, which has 1 channel CdTe cooled detector. The obtained X-ray attenuation coefficients of several samples were very close to the theoretical values. This indicates a possibility to obtain the electron density and atomic number with enough accuracy for medical application.
(17:15- 17:30) Miss Naijun Xu (Zhejiang University, China)
A Novel Hybrid ZCS ZVS Current Control Method For Micro-inverters
Abstract: Boundary current mode (BCM) zero voltage switching method is proposed to help inverters have better performances with higher conversion efficiency. But the modulations increase MOSFETs conduction losses and inductor core losses due to its rapidly changed bandwidth. In this paper, a novel hybrid current modulation, which combines zero current switching（ZCS） and zero voltage switching(ZVS) is proposed to further improve the efficiency and narrow the switching frequency range of the inverters. Finally, a 400W full-bridge inverter and a digital current control platform is built to give experimental results. The experimental results verify that higher efficiency can be achieved using the proposed new modulation.
Contact
Dr Tao Wang
E-mail: twang@zju.edu.cn
College of Electrical Engineering, Zhejiang University
