Hang Liu Fei Wu
Keiji GOTO Toru KAWANO Ryohei NAKAMURA
Takahiro SASAKI Yukihiro KAMIYA
Xiang XIONG Wen LI Xiaohua TAN Yusheng HU
Anton WIDARTA
Hiroshi OKADA Mao FUKINAKA Yoshiki AKIRA
Shun-ichiro Ohmi
Tohgo HOSODA Kazuyuki SAITO
Shohei Matsuhara Kazuyuki Saito Tomoyuki Tajima Aditya Rakhmadi Yoshiki Watanabe Nobuyoshi Takeshita
Koji Abe Mikiya Kuzutani Satoki Furuya Jose A. Piedra-Lorenzana Takeshi Hizawa Yasuhiko Ishikawa
Yihan ZHU Takashi OHSAWA
Shengbao YU Fanze MENG Yihan SHEN Yuzhu HAO Haigen ZHOU
Ryo KUMAGAI Ryosuke SUGA Tomoki UWANO
Jun SONODA Kazusa NAKAMICHI
Kaiji Owaki Yusuke Kanda Hideaki Kimura
Takuya FUJIMOTO
Yuji Wada
Fuyuki Kihara Chihiro Matsui Ken Takeuchi
Keito YUASA Michihiro IDE Sena KATO Kenichi OKADA Atsushi SHIRANE
Tomoo Ushio Yuuki Wada Syo Yoshida
Futoshi KUROKI
Jun FURUTA Shotaro SUGITANI Ryuichi NAKAJIMA Takafumi ITO Kazutoshi KOBAYASHI
Yuya Ichikawa Ayumu Yamada Naoko Misawa Chihiro Matsui Ken Takeuchi
Ayumu Yamada Zhiyuan Huang Naoko Misawa Chihiro Matsui Ken Takeuchi
Yoshinori ITOTAGAWA Koma ATSUMI Hikaru SEBE Daisuke KANEMOTO Tetsuya HIROSE
Hikaru SEBE Daisuke KANEMOTO Tetsuya HIROSE
Zhibo CAO Pengfei HAN Hongming LYU
Takuya SAKAMOTO Itsuki IWATA Toshiki MINAMI Takuya MATSUMOTO
Koji YAMANAKA Kazuhiro IYOMASA Takumi SUGITANI Eigo KUWATA Shintaro SHINJO
Minoru MIZUTANI Takashi OHIRA
Katsumi KAWAI Naoki SHINOHARA Tomohiko MITANI
Baku TAKAHARA Tomohiko MITANI Naoki SHINOHARA
Akihiko ISHIWATA Yasumasa NAKA Masaya TAMURA
Atsushi Fukuda Hiroto Yamamoto Junya Matsudaira Sumire Aoki Yasunori Suzuki
Ting DING Jiandong ZHU Jing YANG Xingmeng JIANG Chengcheng LIU
Fan Liu Zhewang Ma Masataka Ohira Dongchun Qiao Guosheng Pu Masaru Ichikawa
Ludovico MINATI
Minoru Fujishima
Hyunuk AHN Akito IGUCHI Keita MORIMOTO Yasuhide TSUJI
Kensei ITAYA Ryosuke OZAKI Tsuneki YAMASAKI
Akira KAWAHARA Jun SHIBAYAMA Kazuhiro FUJITA Junji YAMAUCHI Hisamatsu NAKANO
Seiya Kishimoto Ryoya Ogino Kenta Arase Shinichiro Ohnuki
Yasuo OHTERA
Tomohiro Kumaki Akihiko Hirata Tubasa Saijo Yuma Kawamoto Tadao Nagatsuma Osamu Kagaya
Haonan CHEN Akito IGUCHI Yasuhide TSUJI
Keiji GOTO Toru KAWANO Munetoshi IWAKIRI Tsubasa KAWAKAMI Kazuki NAKAZAWA
Tetsuya ITO Shigeru OGIHARA Yasuhiro HATTORI
In recent years, there has been increasing demand to miniaturize wiring harness connectors in automobiles due to the increasing volume of electronic equipment and so on. With this demand, contact failure caused by the fretting corrosion seems to become a serious problem in the future. In this report, three-dimensional observations using Focused Ion Beam (FIB)-SEM method have been made for tin plated fretting contacts before and after the contact resistance increase with tin plating thickness 5 µm. With these observations, the three dimensional structural transition from tin to tin oxide have been examined.
Jing LI Zhiying MA Jianming LI Lizhan XU
Using a self-developed ASTM test system of contact material electrical properties under low voltage (LV), small-capacity, the current-frequency variable and a photoelectric analytical balance, the electric performance comparison experiments and material weighing of silver-based electrical contact materials, such as silver/tungsten and silver/cadmium oxide contact materials, are completed under LV, pure resistive load and small current at 400 Hz/50 Hz. The surface profiles and constituents of silver/tungsten contact material were observed and analyzed by SEM and EDAX. Researches indicate that the form of the contact material arc burnout at 400 Hz is stasis, not an eddy flow style at 50 Hz; meanwhile, the area of the contact burnout at 400 Hz is less than that of 50 Hz, and the local ablation on the surface layer at 400 Hz is more serious. Comparing the capacities of the silver-based contact materials with different second element such as CAgW50, CAgNi10, CAgC4 and CAgCdO15 at 400 Hz, no matter what the performances of arc erosion resistance or welding resistance, it can be found that the capacities of the silver/tungsten material is the best.
Laijun ZHAO Zhenbiao LI Hansi ZHANG Makoto HASEGAWA
To clarify how the occurrence of contact welding is related to the series of arc duration characteristics in consecutive make and break operations, electrical endurance tests were conducted on commercially available automotive relays, and the voltage waveforms of make and break arcs between the electrodes were recorded with LabVIEW. Experimental results indicate that welding may occur suddenly or randomly with increasing number of operations. A single arc or a group of make or break arcs with a long arc duration does not necessarily result in contact welding, but a group of longer make or break arcs within a narrow range of operation numbers can cause imminent contact welding (such an effect can be called the “group of longer arcing duration effect”). It is confirmed that contact welding may occur in both make and break operations, but the welding probability during make operations is much higher than that during break operations.
Yu-ichi HAYASHI Yoshiki KAYANO Takaaki MIZUKI Hideaki SONE Hiroshi INOUE
When contact failure occurs in a connector in a coaxial high-frequency (HF) signal transmission line, it is well known that common-mode (CM) radiation occurs on the line. We focus on contact conditions in a connector causing such CM radiation. Experiments and simulations verify that CM radiation increases as the contact resistance increases. While the CM current strongly depends on the distribution pattern of contact resistances at a low resistance, the CM current does not depend on these pattern at a high resistance. Our results indicate that it is important to maintain a symmetrical distribution of contact spots whenever the number of such spots is four or more.
Xuerong YE Jie DENG Qiong YU Guofu ZHAI
Generally, the failure rate of a sealed relay is regarded as a constant value, no matter where and how it is used. However, the failure processes of sealed relays won't be the same under different conditions, even for one relay, its failure rate also will be changed during operations. This paper studies the failure process of a kind of sealed relay by analyzing the variations of its time parameters. Among contact resistance and all those time parameters, it is found that closing gap time can indicate the failure process of tested relay very well. For the purpose of verifying this conclusion derived from time parameters, the contacts are observed by microscope after the tested relay failed. Both theoretical calculation result of contacts gap and photos taken by microscope show that the hypothetic failure mode derived from time parameters is reasonable. Based on the failure analysis, the paper also proposes a dynamic reliability estimation method with closing gap time.
Toru SUGIURA Junya SEKIKAWA Takayoshi KUBONO
Silver electrical contacts are separated to generate break arcs in a DC48 V/6-24 A resistive circuit. The transverse magnetic field formed by a permanent magnet is applied to the break arcs. A series of experiments are carried out for two different experimental conditions. One condition is a constant contact separating speed while the magnetic flux density is changed to investigate the shortening effect of the arc duration. Another condition is a constant magnetic flux density while the contact separating speed is changed to investigate the changes in the arc duration and the contact gap when the break arc is extinguished. As a result, with constant separating speed, it is confirmed that the duration of break arcs is shortened by the transverse magnetic field and the break arcs are extinguished when the arc length reaches a certain value L. Under the condition of constant transverse magnetic field, (i) the arc duration is shortened by increasing the separation speed; (ii) the contact gap when the break arc is extinguished is almost constant when the separating speed v is sufficiently faster than 5 mm/s.
Naoya TAKESHITA Junya SEKIKAWA Takayoshi KUBONO
Break arcs are rotated with the radial magnetic field formed by a magnet embedded in the fixed contact. They are generated in a DC42 V resistive circuit. The circuit current when the contacts are closed varies from 5 A to 21 A. The strength of a radial magnetic field for rotating break arcs changes. Arc duration is investigated. Then rotational frequency, arc length and Lorentz force when the periodic rotation of break arcs starts are analyzed to investigate the conditions required to rotate break arcs. The following results are obtained. The arc length L when the rotational motion of the break arc starts is almost constant at a constant magnetic flux density with an increase in circuit current. The arc length L decreases with an increase in the magnetic flux density of the radial magnetic field. The rotational motion of break arcs starts when the arc length L reaches a certain value determined by magnetic flux density. Rotational frequency and Lorentz force increase linearly with an increase in circuit current.
Kiyoshi YOSHIDA Koichiro SAWA Kenji SUZUKI Masaaki WATANABE
Recently, photovoltaic power systems and electric vehicles have been commonly used. Therefore, the importance of DC (direct current) switching is expected to increase in the near future. The authors have been examining a method of evaluating the electrode loss of AgNi contacts for an electromagnetic contactor with a medium DC load current at a resistive circuit. In this study, the arc energy and electrode mass changes were investigated in more detail. We carried out experiments of 100,000 operations for an electromagnetic contactor at a load current of 5 A constant with a source voltage change from 100 to 160 V. The arc duration, contact resistance, arc energy, and electrode mass changes were measured. As a result, the arc duration was found out increase with the source voltage. In addition, the stationary cathode mass change (loss) increased proportion only to the total arc energy. However, the stationary cathode loss per unit arc energy decreased at the highest source voltage.
Hongfei ZHAO Xiaohua WANG Zhiying MA Mingzhe RONG Yan LI
An arc model has been applied in this paper to study the fundamental interruption environment of a 550 kV SF6 single-break tank circuit breaker. The full differential model takes into account of all important physical mechanisms and is implemented into a commercial Computational Fluid Dynamics (CFD) package, PHOENICS. The model takes a magneto-hydro-dynamics (MHD) approach and the governing equations are solved using the Finite Volume Method (FVM). Through the simulation, the flow velocity vector and mach number for capacitive current switching and short-circuit current breaking are analyzed, and flow dynamic characteristics are obtained. The simulation can provide helpful reference for the design of 550 kV SF6 single-break tank circuit breaker.
Yi WU Hailong HE Zhengyong HU Fei YANG Mingzhe RONG Yang LI
This paper focuses on the research of a new high-speed DC switch repulsion mechanism with experimental and simulation methods. Multi-physical equations reflecting the transient electromagnetic field, electric circuit, mechanical motion and material deformation are coupled in the calculation. For the reason of accuracy, skin effect and the proximity effect caused by the current in the coil are also taken into account. According to the simulation results, which indicate several key parameters severely affecting the mechanism speed, a high-speed DC switch repulsion mechanism is developed. By the test of mechanism motion, its average speed can be up to 8.4 m/s and its mechanism response time is 250 µs, which verifies the simulation results. Furthermore, during high speed motion the stress on the metal plate and moving contact is also discussed. It is noticed that the influence of the material deformation on the mechanical motion is very important.
Ruiliang GUAN Hongwu LIU Nairui YIN Yanfeng HE Degui CHEN
With measuring the arc current, arc voltage and arc images, the high-current air arc commutation process across the separated electrodes was investigated. It shows that the existence of a short stable arc in the gap may increase the current commutation time. According to the energy balance of the arc column, the conditions to maintain the short stable arc were introduced and the effects of the current limiting resistance on the current commutation process were discussed.
Xingwen LI Shenli JIA Yimin YOU Zongqian SHI
The paper is devoted to the experimental study of the arc plasma characteristics in SF6, N2 and CO2. To one flexible model of gas circuit breaker, short circuit experiments have been carried out considering the influence of contact gap (4–12 mm), gas pressure (1–5 atm), short circuit current (1–5 kA effective value) as well as gas species particularly. During the experiments, the arc image, arc current and arc voltage are recorded by the high speed camera, shunt and voltage transducer, respectively. It demonstrates that to the above mentioned three kinds of gases, the arc radius and arc voltage increase with the short circuit current and gas pressure normally; however, under the same experimental conditions, N2 arc holds the minimum arc radius and the maximum arc voltage, and the arc voltage of SF6 arc is the lowest.
Yu-ichi HAYASHI Takaaki MIZUKI Hideaki SONE
Recently, for electronic devices operating at high frequencies, the suppression of a high-frequency electromagnetic field of 1 GHz or more has become necessary. We focus on a loose connector between a pair of electrical devices operating in the high-frequency band. Many electronic devices are used in living spaces, most of which are connected to one another. When a user connects two devices, achieving good contact only by finger tightening can be difficult. Accordingly, in this paper, considering the case where the tightening torque of a coaxial connector is insufficient, we analyze the effect of loose contact on electromagnetic field radiation from a transmission line.
Kazuaki MIYANAGA Yoshiki KAYANO Takashi KOMAKINE Hiroshi INOUE Tasuku TAKAGI
In this paper, to clarify the thermal effect of the bridge for long lifetime contacts, the effects of heat conductivity on bridge break at different material contact pairs were discussed experimentally. To examine the relationship between the bridge and material, the electrode materials of the anode and the cathode were chosen as the same and the different material pairs in this experiment. Ag, AgPd60 and Pd were chosen as the electrode materials, because Ag, AgPd60 and Pd had the different thermal diffusivity. Firstly, the voltage waveforms in the bridge with different material pair were compared to the voltage waveform with the same material pair case. Secondary, the effects of heat conductivity on the break of bridge were discussed. In the results, the bridge voltage waveform depends on the electrode material at anode side. The length of the bridge at bridge break depends on the heat conductivity of the electrode material at anode side. This study provides the basic considerations on the thermal condition of the bridge break.
In order to study the influences of contact opening speeds on arc extinction gap length characteristics, Ag contacts were operated to break DC inductive load currents from 0.1 A to 2.0 A at 14 V with contact opening speeds of 0.5 mm/s, 1 mm/s, 2 mm/s, 5 mm/s and 10 mm/s in a switching mechanism employing a stepping motor, and arc voltage waveforms were observed at each opening of the contacts. From the results, the average arc durations were determined at each current level under the respective contact opening speeds, and the average arc extinction gap lengths were calculated by multiplying the average arc duration value and the contact opening speed value. It was found that average arc durations showed no significant differences with increasing contact opening speeds. Thus, arc extinction gaps became larger at faster opening speeds in the inductive load conditions of this study.
Toru SEGAWA Shinji MATSUO Takaaki KAKITSUKA Yasuo SHIBATA Tomonari SATO Yoshihiro KAWAGUCHI Yasuhiro KONDO Ryo TAKAHASHI
We present an 8
Pichai ARUNVIPAS Chokchai SANGDAO Ravee PHROMLOUNGSRI
This paper presents novel structures of band-pass filters using two configurations of open loop ring resonators (OPLRR): a resonator with embedded quadruply-stepped impedance transmission lines (QSITL) in coupled lines, and a stepped impedance resonator (SIR). Both types of OPLRR have the capability of suppressing the second spurious response and shifting the third spurious response to a higher frequency as well. To demonstrate the performances of both proposed resonators, two sections of each structure with cascaded and crossed configurations at an operating frequency of 0.9 GHz are presented. Both methodologies are easy to design and implement. The methodology with a SIR has a better performance than the SITL. The measurement results of the proposed circuits are in full agreement with the simulated prediction results.
Huey Chian FOONG Meng Tong TAN Yuanjin ZHENG
This paper presents the design and implementation of a supply and process-insensitive 12-bit Digital Pulse Width Modulator (DPWM) for digital DC-DC converters. The DPWM is realized by a ring oscillator-based segmented tapped delay line and a counter-comparator. The number of delay cells required is reduced by employing a proposed delay cell reuse technique. The ring oscillator of the tapped delay line is made insensitive to supply and process variation by biasing the differential delay cells with a supply-insensitive replica bias circuit. Simulation results show that the variation of the switching frequency of the DPWM at 1.02 MHz is 0.4% for supply voltage variation between 1.5 V and 2.5 V and 0.95% over the temperature range from -40
Chun-Hsun WU Le-Ren CHANG-CHIEN
Low drop-out regulators (LDOs) are widely used in the system-on-a-chip (SoC) design. Due to the multi-function and energy saving requirements for mobile applications nowadays, more strict specifications are expected on the developmental roadmap of the LDOs. An output-capacitorless LDO providing fast transient response under the low supply voltage and low quiescent current conditions is proposed in this paper. Provided by the low supply voltage, the proposed LDO adopts cascading technique using the Multipath Nested Miller Compensation (MNMC) to maintain a higher bandwidth for fast transient requirement. In addition, a Transient Quiescent Current Booster (TQCB) is supplemented to the operational amplifier to improve the slew rate for the fast load transient. The TQCB only raises the quiescent current during the load transient instant so that both power saving and the load response improvement could be well achieved. It deserves noting that the proposed TQCB contains only two transistors, which is simple to be implemented compared to the other transient current enhancement techniques. The designed LDO has only 1.6 pF capacitance for the totally added on-chip compensation, and 25.8 µA of current consumption in the main amplifier. The recovery time under the fast load change is less than 3 µs and the stability is guaranteed. Test results from the real implementation of a 0.35 µm CMOS process verify that the designed LDO performs as expected.
Yupin SUPPAKHUN Pornchai SUPNITHI Yoshihiro OKAMOTO Yasuaki NAKAMURA Hisashi OSAWA
In this paper, we propose a new method to estimate and effectively reduce the effect of thermal asperity (TA) in the perpendicular magnetic recording (PMR) channels with the state trellis. The TA is estimated from the state trellis, then its average is used to modify the equalized signal entering the Viterbi detector. For the partial response (PR) targets with DC component, the proposed method with a maximum-likelihood detector can improve the bit error rate performance by more than an order of magnitude when TA occurs and degrades when the giant magneto-resistive (GMR) nonlinearity and base line wander (BLW) effects are present. Unlike the previous studies, this method allows the use of PR targets with DC component under the presence of TA.
Haiyan JIN Xianzhi DU Fulin XIAO Guangjun WEN
In this paper, we propose a wideband four-way turnstile-junction waveguide divider/combiner in the Ka-band. The proposed divider/combiner has an insertion loss of less than 0.8 dB over the frequency range of 28–39.5 GHz. A power combiner amplifier using this circuit and four MMIC amplifiers has been demonstrated with 83% combining efficiency at 34.9 GHz. The measured results show that the turnstile-junction waveguide divider-combiner is a suitable element for developing a broadband millimeter-wave spatial power combiner amplifier.
Joon-Yub KIM Yeon Tae JEONG Byung-Gwon CHO
The address discharge characteristics formed when an address pulse is applied in AC plasma display panels are investigated by changing the ramp-down voltage during the reset period. The address discharge time lag can be reduced when the difference between the ramp-down voltage and the scan-low voltage is set at a high value during the ramp-down period because the loss of the wall charges accumulated between the scan (Y) and address (A) electrodes during the reset period is minimized. In addition, the voltage applied to the X electrode during the ramp-down period can prevent the voltage margin from reduction even though applying high voltage difference on the Y electrodes.
In this brief paper, both static and dynamic behaviors of an electrostatic-actuated MEMS mirror are modeled and studied. To overcome the intrinsic pull-in problem and the dynamic disadvantages in the open-loop controlled actuation, a novel closed-loop feedback control method is proposed assuming the mirror tilt angle can be measured. First, a fixed voltage slightly higher than the pull-in voltage is applied when the mirror tilt angle is small. Then Proportional-Derivative (PD) control is used when the mirror is approaching the target position. Simulink simulation results show that this combined PD closed-loop control can overcome the pull-in problem and improve the dynamic behavior; furthermore, it can also enhance the robustness of the mirror actuation system to overcome environmental disturbances.
Dong-Su LEE Sung-Chan KANG Young-Hyun JUN Bai-Sun KONG
In this letter, a novel body bias selection scheme for minimizing the leakage of MOS transistors is presented. The proposed scheme directly monitors leakages at present and adjacent body bias voltages, and dynamically updates the voltage at which the leakage is minimized regardless of process and temperature variations. Comparison results in a 46 nm CMOS technology indicated that the proposed scheme achieved leakage reductions of up to 68% as compared to conventional body biasing schemes.