Faculty Profiles - YAMAMOTO Masayoshi

Papers - YAMAMOTO Masayoshi

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Analysis of false turn-on phenomenon of GaN HEMT with parasitic inductances for propose novel design method focusing on peak gate voltage

Ishiwaki S., Iwaki T., Sugihara Y., Nanamori K., Yamamoto M.

2017 IEEE Energy Conversion Congress and Exposition, ECCE 2017 Vol. 2017-January page： 1395 - 1401 2017.11

Language：Japanese Publisher：2017 IEEE Energy Conversion Congress and Exposition, ECCE 2017

GaN HEMT is generally characterized as fast switching and expected to achieve a power converter with high efficiency and high power density as a next-generation power semiconductor. However, the fast switching generates large switching noise, causing gate voltage fluctuation. Therefore, GaN HEMT can suffer from false triggering such as a false turn-on phenomenon due to its own low threshold voltage. The phenomenon is problematic especially for practical applications such as a half-bridge circuit. In order to elucidate this phenomenon, we derived the equation expressing gate voltage fluctuation. As a result, the gate voltage fluctuation was described as a composite waveform including two resonance frequencies. Additionally, the appropriateness of the analysis result was supported by comparing theoretical peak gate voltage of the simulation and experimental results. On the other hand analytical results indicated likelihood that balancing factors included in an analytical expression suppress false turn-on phenomenon. Although analytical treatment elucidated gate voltage fluctuation comprehensively, theoretical equation is complicated as design guideline to avoid the false turnon phenomenon. Therefore, this paper analyzed the gate voltage fluctuation mathematically based on L'Hopital's Rule and derived the minimum condition of the peak gate voltage. As a result, mathematical treatment proposes a design method focusing on a peak gate voltage that can achieve the safe operation of a halfbridge circuit.

DOI： 10.1109/ECCE.2017.8095953

Scopus

Magnetic structure of Close-coupled inductors to improve the thermal handling capability in interleaved DC-DC converter Reviewed International coauthorship International journal

Chuong T.H., Kimura S., Ebisumoto D., Noah M., Ishihara M., Yamamoto M., Imaoka J., Martinez W.

2017 IEEE Energy Conversion Congress and Exposition, ECCE 2017 Vol. 2017-January page： 205 - 210 2017.11

Language：English Publishing type：Research paper (scientific journal) Publisher：2017 IEEE Energy Conversion Congress and Exposition, ECCE 2017

Interleaved DC-DC converter employing closecoupled inductors is a popular topology among other power converters topologies. Close-coupled inductors allow the power converter to achieve high power density and high efficiency. This paper proposes a novel magnetic structure of close-coupled inductors suitable for increasing the thermal handling capability. The proposed magnetic structure is combined of different magnetic materials, namely, ferrite and powder cores. The design method of the integrated close-coupled inductors are presented. Furthermore, this design method is considering the DC bias superposition characteristics, and the iron and copper losses as well. A 300W prototype is built to validate the proposed analysis. Finally, excellent heat dissipation of the proposed magnetic structure of the integrated close-coupled inductors is also reported.

DOI： 10.1109/ECCE.2017.8095782

Scopus

Mathematical analysis of GaN high electron mobility transistor false turn-on phenomenon Reviewed International coauthorship International journal

Iwaki T., Ishiwaki S., Sawada T., Yamamoto M.

ELECTRONICS LETTERS Vol. 53 ( 19 ) page： 1327 - 1329 2017.9

A Lagrangian Dynamics Model of Integrated Transformer Incorporated in a Multi-phase LLC Resonant Converter Reviewed International journal

Noah Mostafa, Umetani Kazuhiro, Endo Shun, Ishibashi Hiraki, Imaoka Jun, Yamamoto Masayoshi

2017 IEEE ENERGY CONVERSION CONGRESS AND EXPOSITION (ECCE) page： 3781 - 3787 2017

Modeling and Design of Interleaved Multi-phase DC-DC Converter with 2-phase Coupled Inductor Cell for High Power Density Reviewed International journal

Kimura Shota, Nanamori Kimihiro, Yamamoto Masayoshi

2017 IEEE 6TH INTERNATIONAL CONFERENCE ON RENEWABLE ENERGY RESEARCH AND APPLICATIONS (ICRERA) page： 416 - 422 2017

Analytical Investigation on Design Instruction to Avoid Oscillatory False Triggering of Fast Switching SiC-MOSFETs

Sugihara Yusuke, Nanamori Kimihiro, Ishiwaki Seiya, Hayashi Yuma, Aikawa Kyota, Umetani Kazuhiro, Hiraki Eiji, Yamamoto Masayoshi

2017 IEEE ENERGY CONVERSION CONGRESS AND EXPOSITION (ECCE) page： 5113 - 5118 2017

Analytical Investigation of Interleaved DC-DC Converter using Closed-Coupled Inductor with Phase Drive Control

Ebisumoto Daigoro, Kimura Shota, Nanamori Kimihiro, Noah Mostafa, Ishihara Masataka, Imaoka Jun, Yamamoto Masayoshi

2017 IEEE INTERNATIONAL TELECOMMUNICATIONS ENERGY CONFERENCE (INTELEC) page： 526 - 529 2017

Analysis of False Turn-On Phenomenon of GaN HEMT with Parasitic Inductances for Propose Novel Design Method Focusing on Peak Gate Voltage

Ishiwaki Seiya, Iwaki Toshihiro, Sugihara Yusuke, Nanamori Kimihiro, Yamamoto Masayoshi

2017 IEEE ENERGY CONVERSION CONGRESS AND EXPOSITION (ECCE) page： 1395 - 1401 2017

An Mathematical Analysis of False Turn-On Phenomenon of GaN HEMT

Iwaki Toshihiro, Sawada Takashi, Yamamoto Masayoshi

2017 IEEE CPMT SYMPOSIUM JAPAN (ICSJ) page： 189 - 190 2017

An Investigation into a Slight-Variation of the Transformer Effective Permeability in LLC Resonant Converter

Noah Mostafa, Endo Shun, Kimura Shota, Yamamoto Masayoshi, Imaoka Jun, Umetani Kazuhiro, Hiraki Eiji

2017 19TH EUROPEAN CONFERENCE ON POWER ELECTRONICS AND APPLICATIONS (EPE'17 ECCE EUROPE 2017

An Analysis of False Turn-On Phenomenon of GaN HEMT with Parasitic Components

Iwaki Toshihiro, Ishiwaki Seiya, Sawada Takashi, Yamamoto Masayoshi

2017 IEEE INTERNATIONAL TELECOMMUNICATIONS ENERGY CONFERENCE (INTELEC) page： 347 - 350 2017

Allowable Power Analysis and Comparison of High Power Density DC-DC Converters with Integrated Magnetic Components

Kimura Shota, Nanamori Kimihiro, Kawakami Taichi, Imaoka Jun, Yamamoto Masayoshi

IEEJ Journal of Industry Applications Vol. 6 ( 6 ) page： 463 - 472 2017

Language：Japanese Publisher：The Institute of Electrical Engineers of Japan

<p>Interleaved dc-dc converters with integrated magnetic components are popular as converters capable to achieve high efficiency with less of volume and mass. There are three methods for integrated magnetic components: loosely-coupled inductors, closed-coupled inductors and integrated-winding-coupled inductors. This paper presents a method to calculate the allowable power in various circuit topologies. It is useful for measuring the allowable power without magnetic saturation of an inductor based on its size. Following the analysis of allowable power for each coupled inductor, the allowable power of the integrated magnetic components is compared to that of the conventional interleaved converter. This comparison is realized under the same conditions. As a result, the interleaved converter with loosely-coupled and integrated winding coupled inductors were found to be effective for the downsizing of the magnetic components under continuous conduction mode operation. On the other hand, the interleaved converter with close-coupled inductors is effective for the downsizing of the magnetic components under critical conduction mode operation. This comparative data is discussed from both theoretical and experimental points of view.</p>

DOI： 10.1541/ieejjia.6.463

Web of Science

Scopus

CiNii Research

A Novel LLC Resonant DC-DC Converter with Integrated Transformer Reviewed International coauthorship International journal

Kimura Shota, Nanamori Kimihiro, Noah Mostafa, Yamamoto Masayoshi

2017 IEEE INTERNATIONAL TELECOMMUNICATIONS ENERGY CONFERENCE (INTELEC) page： 506 - 510 2017

Power Flow Interactive Sharing between Two DC Nanogrids Photovoltaic Local Branch Dynamic System at Island Operation

Bauomy Maged F., Gamal Haytham, Shaltout Adel A., Noah Mostafa, Yamamoto Masayoshi

2017 19TH EUROPEAN CONFERENCE ON POWER ELECTRONICS AND APPLICATIONS (EPE'17 ECCE EUROPE) 2017

Magnetic Structure of Close-Coupled Inductors to Improve the Thermal Handling Capability in Interleaved DC-DC Converter Reviewed International coauthorship International journal

Chuong, TH; Kimura, S; Ebisumoto, D; Noah, M; Ishihara, M; Yamamoto, M; Imaoka, J; Martinez, W

2017 IEEE ENERGY CONVERSION CONGRESS AND EXPOSITION (ECCE) page： 205 - 210 2017

Analysis of Self Turn-ON Phenomenon for the Application of Power Semiconductor Devices

Proceedings of Microelectronics Symposium Vol. 27 ( 0 ) page： 15 - 16 2017

Analyzing visitors' characteristics in tourist areas based on mobile phone users' location data

Yamamoto M.

Conference Proceedings - 23rd ISSAT International Conference on Reliability and Quality in Design page： 1 - 5 2017

Language：Japanese Publisher：Conference Proceedings - 23rd ISSAT International Conference on Reliability and Quality in Design

In recent years, so-called "big data" have been attracting the attention of companies and researchers. This study aims to identify the number of visitors of each period and their characteristics based on the location data of mobile phone users collected by the mobile phone company. The study sites of this survey are tourist destinations in Ishikawa Prefecture and Toyama city, including Kanazawa city, which became nationally popular after the Hokuriku Shinkansen opened in 2015. The opening of the Hokuriku Shinkansen brought more visitors to many areas. However, it also led to fewer visitors in some areas. The positive effect was remarkable in Kanazawa.

Scopus

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Papers - YAMAMOTO Masayoshi