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Natsuki Kawaguchi, Kazuma Nakata, Ryota Ohnishi, Ippei Tanaka
2024 Volume 144 Issue 3 Pages
127-132
Published: March 01, 2024
Released on J-STAGE: March 01, 2024
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We propose a method of designing a FRIT(Fictious Reference Iterative Tuning)-based control system for a microwave plasma CVD(Chemical Vapor Deposition) apparatus used in the preparation of diamond thin films. Specifically, we propose a control system that adjusts the flow rate ratio of CH4 and H2, the material gases, using the spectral emission intensity ratio of the plasma, which affects the film quality, as the controlled variable. We show how to design an experimental apparatus including actuators and sensors for this purpose. The FRIT method, a well-known data-driven control method, is used to design the controller gain from a set of experimental data without modeling complex objectives such as plasma behavior. Through control experiments of the emission intensity ratio, it is shown that the controller gain can be tuned by using a reference model with different time constants to adjust the performance of the response of the control system.
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Masato Tanaka
2024 Volume 144 Issue 3 Pages
133-139
Published: March 01, 2024
Released on J-STAGE: March 01, 2024
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In this paper, general-purpose uniform temperature control for heating process systems is described. The uniform temperature control function should be implemented to a local PID temperature controller. The controller is supplied to the heating process equipment manufacturer. In composition of the business, the adequacy of the relations between companies of the control technology is an important issue.
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Toshitaka Matsuki, Taisei Indou, Yuto Wada, Masayoshi Hara, Masanori T ...
2024 Volume 144 Issue 3 Pages
140-147
Published: March 01, 2024
Released on J-STAGE: March 01, 2024
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Self-repairing PID control has been proposed as an active fault-tolerant control system that tolerates component malfunctions, maintaining desired performance. In this method, an auxiliary signal with the same sign as the control quantity is added to the integrator to cause minute oscillations in the control quantity, and a fault is diagnosed by detecting the bias in the integral value due to the occurrence of a fault. This method has the tradeoff that a larger auxiliary signal reduces fault detection time but negatively affects control performance. This paper proposes the auxiliary signal whose value is determined by the function of the control quantity to improve the performance of the self-repairing PID control. Simulation results show that the function of the auxiliary signal effectively reduces detection time and improves control performance. Additionally, the performance of the system is evaluated while varying the design parameters, and some insight into the design guidelines for the function is found.
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Zhao Li, Nozomu Otakara, Nozomu Kato, Ikuro Mizumoto
2024 Volume 144 Issue 3 Pages
148-155
Published: March 01, 2024
Released on J-STAGE: March 01, 2024
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Adaptive output feedback control based on output feedback exponential passivity (OFEP) has a simple structure and strong robustness in regard to disturbances and system uncertainties. However, it is difficult for most nonlinear systems to satisfy the conditions of OFEP. Thus, the introduction of a suitable parallel feedforward compensator (PFC) to construct an OFEP augmented system with the controlled system has been used, but the control output cannot achieve perfect tracking because of the output of the introduced PFC. As a solution, introducing a feedforward (FF) input to build a 2 degree of freedom (2-DOF) is a simple and effective way to solve this problem. In this paper, we propose the design schemes for suitable PFC and FF input of nonlinear systems via the use of neural networks (NN) respectively. And besides, to cope with possibly present input disturbances, we also provide a method to achieve disturbance compensation based on NN to reduce their interference. Finally, the effectiveness of all proposed design schemes is confirmed through numerical simulations.
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Keita Murai, Kazuo Kawada
2024 Volume 144 Issue 3 Pages
156-161
Published: March 01, 2024
Released on J-STAGE: March 01, 2024
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With the arrival of the Society 5.0 era, STEAM education is attracting attention, and the Sixth Science, Technology, and Innovation Basic Plan (2021) includes STEAM education for the first time as a science and technology policy, and efforts are underway in school education. In addition, programming education in elementary schools has been made compulsory from 2020, and this has led to the enhancement of programming education in general education. However, there are few practices that incorporate measurement and control technology as part of programming education in elementary schools. In this study, we developed measurement and control technology learning materials for elementary schools that can be practiced as STEAM education. Using kinetic art as a learning material, we proposed a learning content of making a peacock that moves by measurement and control and conducted a class for 6th grade elementary school students. After the class, we conducted a questionnaire survey of the students and their homeroom teachers to verify the usefulness of the learning materials and the class.
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Yuta Susawa, Genryu Takahashi, Keita Murai, Kazuo Kawada, Shin Wakitan ...
2024 Volume 144 Issue 3 Pages
162-168
Published: March 01, 2024
Released on J-STAGE: March 01, 2024
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In order to realize the "Society 5.0" proposed by the Cabinet Office, human resource development to create new value is attracting attention. In addition, the industrial world is promoting "model-based development (MBD)," which enables efficient development through simulations using mathematical models. In this study, we develop and implement a curriculum to promote model-based development (MBD) thinking at the high school level and test its educational effects. Specifically, the curriculum is to design an advanced emergency braking system through simulation, and to verify the simulation results by using the operation of automotive learning materials.
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Kanami Sato, Natsuki Kawaguchi, Naoki Hayashi, Naoyuki Hara, Takao Sat ...
2024 Volume 144 Issue 3 Pages
179-180
Published: March 01, 2024
Released on J-STAGE: March 01, 2024
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The present study proposes a design methodology for blade pitch angle control of offshore wind turbines. A wind farm is formulated as a multi-agent system, and an event-driven distributed control system is designed to reduce the number of data communications.
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Jun Obara, Naoyuki Aikawa
2024 Volume 144 Issue 3 Pages
181-182
Published: March 01, 2024
Released on J-STAGE: March 01, 2024
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In general, it is known that highly accurate weight measurement is not possible when the measuring instrument or the object to be measured is shaking. The weight is a DC component, and the AC component is noise. Hilbert transformer can estimate the frequency corresponding to the noise, but contains error. In this paper, we show a method for accurately measuring the weight of a liquid by correcting the error caused by the Hilbert transformer.
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Takeshi Ikegami, Shinichi Imai
2024 Volume 144 Issue 3 Pages
183-184
Published: March 01, 2024
Released on J-STAGE: March 01, 2024
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In order to analyze check the class individually by making our rounds in the classroom quantitatively, it is necessary to develop a system that replaces the existing analysis method of visual video recording. The purpose of this study is to develop a system that records the trajectory of a teacher using a two-dimensional sensor. The position of a teather is measured from the point cloud data output by the sensor, and after background subtraction, the point cloud data is calculated by grouping the student's point clouds. Experiments were conducted to examine the validity of the position measurement method used.
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Special Issue on “The latest silicon and wide bandgap power semiconductor technologies”
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Yuri Fujimoto, Shin-ichi Nishizawa, Wataru Saito
2024 Volume 144 Issue 3 Pages
198-203
Published: March 01, 2024
Released on J-STAGE: March 01, 2024
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Surge voltage at IGBT turn-off switching was analyzed with dependence on cell design parameters. Although drift layer thinning is effective to improve trade-off characteristics between turn-off loss Eoff and on-state voltage Von, voltage surge is induced due to quick expanding depletion layer. Therefore, the surge voltage Vsurge has also trade-off relationship with the Von at the same Eoff condition. The origin of voltage surge was analyzed using TCAD simulation, and total amount of remained hole in the drift layer during turn-off switching is a key factor for the Vsurge. Narrow mesa structure and thick buffer layer are effective for improvement of trade-off characteristics between Vsurge and Von.
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Kailun Yao, Noriyuki Iwamuro
2024 Volume 144 Issue 3 Pages
204-211
Published: March 01, 2024
Released on J-STAGE: March 01, 2024
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The mechanical short-circuit failure mode of 1.2 kV class SiC MOSFETs was investigated by experiment and electro-thermal-mechanical technology computer-aided design (TCAD) simulation. In this work, the details of the simulation procedure are described. TCAD simulations provide a powerful means to address the mechanical failure of such devices, and indicates that high-level stress concentrates at the gate dielectric layer because of the large thermal expansion coefficient of the source metal. Further, a low mechanical stress design for short-circuit in SiC MOSFETs is proposed by using low thermal expansion metal such as copper as the source electrodes.
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Ryohei Gejo, Tatsunori Sakano, Yoko Iwakaji
2024 Volume 144 Issue 3 Pages
212-216
Published: March 01, 2024
Released on J-STAGE: March 01, 2024
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Insulated gate bipolar transistors (IGBTs) are now widely used in a variety of products ranging from home appliances to power conversion equipment. This paper introduces multi-gate control techniques for IGBTs with the aim of further reducing their total power loss. Results of experiments using prototype devices confirmed that multi-gate control achieves reductions in turn-off loss (Eoff), turn-on loss (Eon) and reverse recovery loss (Err) by 27%, 50% and 32%, respectively, compared with the conventional single-gate controlled devices.
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Atsushi Sakai, Katsumi Eikyu, Yotaro Goto, Eiji Tsukuda, Tamotsu Ogata
2024 Volume 144 Issue 3 Pages
217-220
Published: March 01, 2024
Released on J-STAGE: March 01, 2024
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This paper presents the negative drain input measurements of fully isolated nLDMOS which is fabricated by a low-cost process without any additional epitaxial growth. The critical drain current which causes the parasitic PNP activation is proposed as the index of the negative drain input withstand capability. The device size dependence measurements show that the negative drain input withstand capability decreases as the internal LDMOS area increases which is surrounded by the n-type isolation layer electrode. And, the bias application measurements to n-type isolation layer show that the trade-off relation between the anomalous substrate leakage and the parasitic PNP activation; that is, the higher applied bias suppresses the parasitic PNP activation but makes the anomalous substrate leakage larger.
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Tomoyuki Miyoshi, Hiroshi Suzuki, Takashi Hirao, Yusuke Takada, Tomoya ...
2024 Volume 144 Issue 3 Pages
221-227
Published: March 01, 2024
Released on J-STAGE: March 01, 2024
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A concept on High-conductivity IGBT with Time And Space Control of stored carrier (TASC HiGT) for pursuit of low-loss is proposed. The function is divided into high-conductivity chip (Hc) and high-speed chip (Hs) controlled by Dual-gate so as to exhibit the optimum stored carrier density for conduction and switching operation. By obtaining controllability of the stored carrier density over the drift, a ‒47% trade-off improvement on 6.5 kV rated was demonstrated. The proposed concept can generate further ‒34% inverter loss effect keeping low-cost Si material merit.
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Shinya Soneda, Kazuya Konishi, Kenji Suzuki, Kosuke Sakaguchi, Akihiko ...
2024 Volume 144 Issue 3 Pages
228-233
Published: March 01, 2024
Released on J-STAGE: March 01, 2024
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In this paper, a newly developed 3rd Gen. RC-IGBT is presented. To reduce the power loss and improve the heat dissipation of RC-IGBTs, we introduced four approaches, controlling Gate-capacitances, thin wafer technique, high-density diode arrangement, and low carrier injection anode and cathode. The superior performance of the 3rd Gen. RC-IGBT is very promising for the carbon neutral.
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Fumio Otsuka, Hironobu Miyamoto, Shinji Kunori, Kohei Sasaki, Akito Ku ...
2024 Volume 144 Issue 3 Pages
234-239
Published: March 01, 2024
Released on J-STAGE: March 01, 2024
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We fabricated high forward and low leakage current trench MOS-type Schottky barrier diodes (MOSSBDs) on a 12-μm-thick epitaxial layer grown by halide vapor phase epitaxy on β-Ga2O3(001) substrate. The MOSSBDs, measuring 1.7×1.7 mm2, exhibited a forward current of 2 A (70 A/cm2) at 2 V forward voltage and a leakage current of 2×10-8 A/cm2 at -1.2 kV reverse voltage (on/off current ratio of > 109) with an ideality factor of 1.05 and wafer-level specific on-resistance of 17.1 mΩ·cm2. These results indicate that the MOSSBD is promising for practical high-voltage (AC 400 V) power applications.
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Yoshihiro Ikura, Akio Nakagawa
2024 Volume 144 Issue 3 Pages
240-244
Published: March 01, 2024
Released on J-STAGE: March 01, 2024
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In this work, we report a newly developed analysis method to investigate the mechanism of turn-on voltage tail of IGBT, aiming at the reduction of turn-on loss (Eon). This analysis method visualizes how gate-collector capacitance (CGC) increases by monitoring the potential change at the interface of the gate oxide and silicon around the gate trench during the turn-on process. It was found that, in the turn-on transient, initially, the collector-emitter voltage (VCE) decrease, and CGC increase drastically when the potential around the gate trench falls below the gate-emitter voltage (VGE) and that the sudden increase of CGC causes the turn-on voltage tail. Detailed TCAD analysis reveals that the electric potential around the gate trench is lowered by the dummy trench and causes the sudden increase of CGC. To verify that the dummy trench is origin of the turn-on voltage tail, full gate trench IGBT with no dummy trench is studied. In the full gate trench IGBT, neither sudden increase of CGC nor turn-on voltage tail are observed.
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Takuya Saraya, Kazuo Ito, Toshihiko Takakura, Shinichi Suzuki, Munetos ...
2024 Volume 144 Issue 3 Pages
245-250
Published: March 01, 2024
Released on J-STAGE: March 01, 2024
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Back-gate-controlled IGBT (BC-IGBT) which uses a manufacturable double side lithography is experimentally demonstrated. The impact of IGBT scaling on BC-IGBT is evaluated in detail. A back gate control (BC-) mode in scaled IGBT shows better performance improvement compared with the BC-mode in non-scaled IGBT. Superior performance of BC-IGBT by optimizing both front side and back side design has been realized. Back gate control with scaled IGBT will provide a new technological option for expanding the frequency/voltage range of Si power devices, and become an attractive candidate for next generation high performance IGBTs.
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Yoshinao Miura, Hirohisa Hirai, Akira Nakajima, Shinsuke Harada
2024 Volume 144 Issue 3 Pages
251-256
Published: March 01, 2024
Released on J-STAGE: March 01, 2024
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We propose a new edge termination technique for high-voltage vertical GaN power devices using boron-ion implantation into a p-GaN epitaxial layer. The boron-implanted layer after annealing at 800°C results in a half-conductive p-type layer that is applicable to junction termination extension (JTE). The maximum breakdown voltage of 1400 V was near an ideal value for the donor concentration in the drift layer. High avalanche current immunity was observed for the optimal structure. In wafer-scale fabrication of the p-n diodes on a 4-inch free-standing GaN substrate, good reverse characteristics are observed across the wafer. The proposed JTE technique has high potential for wafer-scale fabrication of robust and highly efficient vertical GaN devices.
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Mitsuru Sometani, Kunihide Oozono, Shiyang Ji, Takeshi Tawara, Tadao M ...
2024 Volume 144 Issue 3 Pages
257-262
Published: March 01, 2024
Released on J-STAGE: March 01, 2024
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We compared static and dynamic characteristics of a 1.2 kV-Class SJ-MOSFET fabricated by the multi-epitaxial growth (ME) method and the trench-filling epitaxial growth (TFE) method, which is expected to have a lower process cost. Comparably low specific on-resistance and switching losses were observed for the SJ-MOSFETs fabricated by both methods.
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