Research Achievements

【Jounal Papers】

• Koya Tsutsumi and Hidemine Obara，"Investigation on the Expansion of Output Voltage Range Using a 9-level DAB Converter with Pulse Amplitude Control"，IEEJ Transactions on Industrial Application, Vol. 144, No. 6, pp. 467-475, 2024-6. (in Japanese) doi: 10.1541/ieejias.144.467

• Atsuo Kawamura, Yukinori Tsuruta, and Hidemine Obara, "Over 99.7% Efficiency at 100 kW DC-DC Power Conversion using 3.3 kV SiC Device and Discussion on Device dv/dt Estimation", IEEJ Journal of Industry Applications, Vol. 13, No. 4, pp. 426-436, 2024-8. doi: 10.1541/ieejjia.23013265

• Van-Long Pham, Hidemine Obara, and Katsuhiro Hata, "A Partial Active Gate Control for Improvement of a Trade-off Relation Between Surge Voltage and Efficiency in a Three-Phase Inverter", IEEE Transactions on Industry Applications, Vol. 60, No. 3, pp. 4239-4250, 2024-5. doi: 10.1109/TIA.2024.3353153

• Yasuhiko Miguchi, Hidemine Obara, and Atsuo Kawamura, "Control Scheme for the Lagging Power Factor Operation of a Single-Phase Grid-Connected Inverter Using an Unfolding Circuit", IEEE Open Journal of Power Electronics, Vol. 5, pp. 145-161, 2024-1. doi: 10.1109/OJPEL.2024.3351147

• Atsuo Kawamura, Yasuhiko Miguchi, Hadi Setiadi, and Hidemine Obara, "Survey of 99.9% Class Efficiency DC-AC Power Conversion and Technical Issues", IEEJ Transactions on Electrical and Electronic Engineering, Vol. 18, No. 1, pp. 6-14, 2023-1. doi: 10.1002/tee.23728

• Yasuhiko Miguchi, Hadi Setiadi, Yoshiki Nasu, Hidemine Obara, and Atsuo Kawamura, "Control Scheme for Leading Power Factor Operation of Single-Phase Grid-Connected Inverter Using an Unfolding Circuit", IEEE Open Journal of Power Electronics, Vol. 3, pp. 468-480, 2022-7. doi: 10.1109/OJPEL.2022.3190559

• Hidemine Obara, Masaya Katayama, Atsuo Kawamura, Jin Xu, and Noboru Shimosato, "A Modular Multilevel DC-DC Converter with Auxiliary Inductor Circuits for Cell Voltage Balancing and Fast Output Response", IEEE Open Journal of Power Electronics, Vol. 3, pp. 391-401, 2022-6. doi: 10.1109/OJPEL.2022.3185645

• Hadi Setiadi and Hidemine Obara, "Multilevel Cascaded H-Bridge Linear Amplifier with Unequal DC Capacitor Voltages Using a DC Voltage Source", IEEJ Journal of Industry Applications, Vol. 11, No. 3, pp. 522-530, 2022-5. doi: 10.1541/ieejjia.21011915

• Almachius Kahwa, Hidemine Obara, and Yasutaka Fujimoto, "Minimization of DC-Link Capacitance and Improved Operational Performance of a 5-Level Hybrid Multilevel DC-Link Inverter", IEEE Open Journal of Power Electronics, Vol. 3, pp. 182-196, 2022-3. doi: 10.1109/OJPEL.2022.3160867

• Atsuo Kawamura, Yoshiki Nasu, Yasuhiko Miguchi, Hadi Setiadi, and Hidemine Obara, "Proposal of Virtual Transformer-based Back-to-Back Asynchronous Loss Measurement using a Single Set of Measurement Instruments for One Inverter and Experimental Verification", IEEJ Journal of Industry Applications, Vol. 11, No. 1, pp. 175-184, 2022-1. doi: 10.1541/ieejjia.21008251

• Daiki Yamaguchi, Yu Shan Cheng, Tomoyuki Mannen, Hidemine Obara, Keiji Wada, Toru Sai, Makoto Takamiya, and Takayasu Sakurai, "An Optimization Method of a Digital Active Gate Driver Under Continuous Switching Operation Being Capable of Suppressing Surge Voltage and Power Loss in PWM inverters", IEEE Transactions on Industry Applications, Vol. 58, No. 1, pp. 481-493, 2022-1. doi: 10.1109/TIA.2021.3124864

• Hidemine Obara, Tatsuki Ohno, and Atsuo Kawamura, "Systematization of a Multilevel-topology-based Linear Amplifier Family for Noiseless DC-AC Power Conversion", IEEE Access, Vol. 9, pp. 159627-159639, 2021-11. doi: 10.1109/ACCESS.2021.3130681

• Hidemine Obara, Tatsuki Ohno, Masaya Katayama, and Atsuo Kawamura: "Flying-Capacitor Linear Amplifier with Capacitor Voltage Balancing for High-Efficiency and Low Distortion", IEEE Transactions on Industry Applications，Vol.57，No.1，2021-1.

• Atsuo Kawamura, Satoshi Nakazaki, Shogo Ito, Sakahisa Nagai, and Hidemine Obara:
  "Over 99.7% Efficiency Two Battery HEECS Inverter at 2.2 kW Output and Discussion on Measurement Accuracy Based on Loss Breakdown",
  IEEJ Journal of Industry Applications，Vol.9，No.6，pp.663-673，2020-11.

• Yoshiki Kosode, Hidemine Obara, Atsuo Kawamura, Yu Hosoyamada, Toyoaki Suenaga, and Itsuo Yuzurihara:
  "High Performance Transient Response of High/Low Pulse Voltage using Two-Phase Interleaved DC-DC Buck Converter under Half Sampling Time Deadbeat Control",
  IEEJ Journal of Industry Applications，Vol.9，No.4，pp.444-452，2020-7.

• Ayataro Tamura, Takayuki Ishibashi, Takuro Umihara, Yukinori Tsuruta, Hidemine Obara, and Atsuo Kawamura:
  "Voltage Control of Intermittent Pulse Density Modulation for Two Battery HEECS Chopper and the Application for Range Extension of Electric Vehicles",
  IEEJ Journal of Industry Applications，Vol.8，No.5，pp.xxx，2019-9.

• Masaya Katayama, Tatsuki Ohno, Hidemine Obara, and Atsuo Kawamura:
  "Application of Multi-Level Converter for Fast Current Control in Small-Scale DC Power Network",
  IEEE Transactions on Industry Applications，Vol.55，No.3，pp.2902-2909，2019-5.

• Hiroyuki Abeta，Hidemine Obara，and Atsuo Kawamura：
  「Multiple Source Input Isolated DC-DC Converter with Simple Circuit」，
  IEEJ Transactions on Industrial Application, Vol.139，No.3，pp.266-275，2019-3. (in Japanese)

• Hidemine Obara, Keiji Wada, Koutaro Miyazaki, Makoto Takamiya, and Takayasu Sakurai:
  "Active Gate Control in Half-Bridge Inverters Using Programmable Gate Driver ICs to Improve both Surge Voltage and Converter Efficiency",
  IEEE Transactions on Industry Applications，Vol.54，No.5，pp.4603-4611，2018-9.

• Aviti Thadei Mushi, Sakahisa Nagai, Hidemine Obara, and Atsuo Kawamura:
  "Fast and Robust Nonlinear Deadbeat Current Control for Boost Converter",
  IEEJ Journal of Industry Applications，Vol.6，No.5，pp.311-319，2017-9

• Kenji Natori, Kouhei Yoshikawa, Hidemine Obara, Yukihiko Sato：
  "Fundamental Control Methods for Power Flow Control in Next-Generation DC Power Networks"，
  IEEJ Transactions on Industrial Application, Vol.136, No.4, pp.277-284, 2016-4. (in Japanese)

• Hidemine Obara, Hiroshi Oguri, and Yukihiko Sato：
  "Theoretical Analysis of Harmonics in PWM Output Waveform of Multi-Level Inverters"，
  Electrical Engineering in Japan (Wiley Online Library)，Vol.191，No.4，pp.55-65，2015-6.

• Hidemine Obara, Yukihiko Sato：
  "Selection Criteria of Capacitors for Flying Capacitor Converters"，
  IEEJ Journal of Industry Applications，Letter, Vol.4，No.2，pp.105-106，2015-3.

• Hidemine Obara, Masamu Kamaga, Takumi Ito, Yukihiko Sato：
  "An Investigation of Capacitors for Flying Capacitor Converters"，
  Electrical Engineering in Japan (Wiley Online Library)，Vol.186，No.4，pp.81-91，2014-3.

• Hidemine Obara，Hiroshi Oguri，Yukihiko Sato：
  「Theoretical Analysis of Harmonics in PWM Output Waveform of Multi-Level Inverters」，
  IEEJ Transactions on Industrial Application, Vol.134, No.1, 2014 (in Japanese)

• Hidemine Obara, Masamu Kamaga, Takumi Ito, Yukihiko Sato：
  "An Investigation of Capacitors for Flying Capacitor Converters",
  IEEJ Transactions on Industrial Application, Vol.131, No.12, pp.1393-1400, 2011 (in Japanese)

【Conference Papers】

• Daiki Yamaguchi, Yu Shan Cheng, Tomoyuki Mannen, Hidemine Obara, Keiji Wada, Makoto Takamiya, Takayasu Sakurai, Toru Sai:
  "Digital Active Gate Control for a Three-Phase Inverter Circuit for a Surge Voltage Suppression and Switching Loss Reduction",
  IEEE Energy Conversion Congress and Exposition (ECCE) 2020, Online, 2020-10.

• Toru Sai, Koutaro Miyazaki, Hidemine Obara, Tomoyuki Mannen, Keiji Wada, Ichiro Omura, Makoto Takamiya, and Takayasu Sakurai:
  "Stop-and-Go Gate Drive Minimizing Test Cost to Find Optimum Gate Driving Vectors in Digital Gate Drivers",
  IEEE Applied Power Electronics Conference (APEC) 2020, New Orleans, USA, 2020-3.

• Toru Sai, Koutaro Miyazaki, Hidemine Obara, Tomoyuki Mannen, Keiji Wada, Ichiro Omura, Makoto Takamiya, and Takayasu Sakurai:
  "Robust Gate Driving Vectors to Load Current and Temperature Variations for Digital Gate Drivers",
  IEEE International Future Energy Electronics Conference (IFEEC) 2019, Singapore, 2019-12.

• Tomoyuki Mannen, Hidemine Obara, Keiji Wada, Toru Sai, Koutaro Miyazaki,Ichiro Omura, Makoto Takamiya, and Takayasu Sakurai:
  "Effect on Digital Active Gate Control of a Practical IGBT Full-Bridge Inverter with the Additional DC-Link Capacitor Close to Power Devices",
  IEEE International Future Energy Electronics Conference (IFEEC) 2019, Singapore, 2019-12.

• Takayuki Ishibashi, Hidemine Obara, and Atsuo Kawamura:
  "Proposal of SOC Unbalancing Solution Combined with Flux-weakening Control for Two-battery HEECS Chopper-based EV Powertrain",
  IEEE International Future Energy Electronics Conference (IFEEC) 2019, Singapore, 2019-12.

• Yoshiki Kosode, Hidemine Obara, Atsuo Kawamura, Yu Hosoyamada, and Itsuo Yuzurihara:
  "Experimental Realization of High Performance Transient Response for Two-Phase Interleaved DC-DC Buck Converter using Half Sampling Time Deadbeat Control",
  Annual Conference of the IEEE Industrial Electronics Society (IECON) 2019, Lisbon, Portugal, 2019-10.

• Hidemine Obara, Tomoyuki Mannen, Keiji Wada, Koutaro Miyazaki, Toru Sai, Makoto Takamiya, and Takayasu Sakurai:
  "Design and Implementation of Digital Active Gate Control with Variable 63-level Drivability Controlled by Serial 4-bit Signals",
  IEEE Energy Conversion Congress and Exposition (ECCE) 2019, Boltimore, MD, USA, 2019-9.(accepted)

• Toru Sai, Koutaro Miyazaki, Hidemine Obara, Tomoyuki Mannen, Keiji Wada, Ichiro Omura, Makoto Takamiya, and Takayasu Sakurai:
  "Load Current and Temperature Dependent Optimization of Active Gate Driving Waveforms",
  IEEE Energy Conversion Congress and Exposition (ECCE) 2019, Boltimore, MD, USA, 2019-9.(accepted)

• Satoshi Nakazaki, Shogo Ito, Hidemine Obara, and Atsuo Kawamura:
  "Discussion on Loss Breakdown of 99.6% Efficiency Two Battery HEECS Inverter",
  European Conference on Power Electronics and Applications (EPE) 2019 -ECCE Europe，Genova, Italy, 2019-9.(accepted)

• Hidemine Obara, Masaya Katayama, Atsuo Kawamura, Jin Xu, Noboru Shimosato, and Satoshi Inoue:
  "Study on Modular Multi-Level DC-DC Converter with Cell Voltage Balancing and Fast Output Response Using Sub Commutation Circuits",
  International Conference on Power Electronics (ICPE) 2019 -ECCE Asia，Busan, Korea, 2019-5.

• Tatsuki Ohno, Masaya Katayama, Hidemine Obara, and Atsuo Kawamura:
  "Flying-Capacitor Linear Amplifier with Capacitor Voltage Balancing Control for Efficient and Low Harmonic Power Conversion",
  IEEE Applied Power Electronics Conference (APEC) 2019, Anaheim, USA, 2019-3.

• Almachius Kahwa, Hidemine Obara, and Yasutaka Fujimoto:
  "Estimation and Analysis of Power Loss in a Reduced Switches Count H-bridge Multilevel Inverter",
  IEEE International Conference on Mechatronics (ICM) 2019, Ilmenau, Germany, 2019-3.

• Ayataro Tamura, Takayuki Ishibashi, Takuro Umihara, Yukinori Tsuruta, Hidemine Obara, and Atsuo Kawamura:
  "High efficiency chopper based EV range extender",
  International Electric Vehicles Sympsium & Exhibition (EVS) 31，A2-3, Hyogo, Japan, 2018-10.

• Atsuo Kawamura, Sakahisa Nagai, Satoshi Nakazaki, Ito Shogo, and Hidemine Obara:
  "A Very High Efficiency Circuit Topology for a few kW Inverter based on Partial Power Conversion Principle",
  IEEE Energy Conversion Congress and Exposition (ECCE) 2018，pp.1308-1313, Portland, OR, USA, 2018-9.

• Sakahisa Nagai, Shogo Ito, Atsuo Kawamura, Satoshi Nakazaki, and Hidemine Obara:
  "Full-wave Rectified Waveform Generation Using Dead-beat Voltage Control for DC-DC Buck Converters to Realize High Efficiency Inverter",
  European Conference on Power Electronics and Applications (EPE) 2018 ECCE-Europe，Riga, Ratvia, 2018-9.

• Hiromi Adachi, Yu Hosoyamada, Atsuo Kawamura, Yoshiki Kosode, Hidemine Obara, and Itsuo Yuzurihara:
  "Half Cycle Iref Deadbeat Control of Two-phase Interleaved DC-DC Buck Converter for High/Low Voltage Pulse Generation",
  European Conference on Power Electronics and Applications (EPE) 2018 ECCE-Europe，Riga, Ratvia, 2018-9.

• Hidemine Obara, Tatsuki Ohno, and Atsuo Kawamura:
  "Multi-level topology based linear amplifier family for realization of noise-less inverters",
  International Power Electronics Conference (IPEC) -ECCE Asia 2018, pp.1649-1654, Niigata, Japan, 2018-5.

• Almachius Kahwa, Hidemine Obara, and Yasutaka Fujimoto:
  "Design of 5-levels Reduced Switches Count H-bridge Multilevel Inverter",
  International Workshop on Advanced Motion Control (AMC) 2018, Tokyo, Japan, 2018-3

• Hiroya Takahashi, Hidemine Obara, and Yasutaka Fujimoto:
  "Dead Time Compensation for Three-level Flying Capacitor Inverter with Phase Shift PWM",
  International Workshop on Advanced Motion Control (AMC) 2018, Tokyo, Japan, 2018-3

• Mannen Tomoyuki, Keiji Wada, Hidemine Obara, Koutarou Miyazaki, Makoto Takamiya, and Takayasu Sakurai:
  "Active Gate Control for Switching Waveform Shaping Irrespective of the Circuit Stray Inductance in a Practical Full-Bridge IGBT Inverter",
  IEEE Applied Power Electronics Conference (APEC) 2018, Portland, USA, 2018-3

• Tatsuki Ohno, Masaya Katayama, Hidemine Obara, and Atsuo Kawamura:
  "Flying Capacitor Linear Amplifier to Realize Both High-efficiency and Low Distortion for Power Conversion Applications Requiring Highquality Waveforms",
  IEEE International Conference on Power Electronics and Drive Systems (PEDS) 2017, 338, pp.907-912, Honolulu, Hawaii, USA, 2017-12

• Masaya Katayama, Tatsuki Ohno,Hidemine Obara, and Atsuo Kawamura:
  "Study on Application of Multilevel Converter to Realize Fast Current Control in DC Microgrid With Extremely Low Impedance Interconnections",
  IEEE International Conference on Power Electronics and Drive Systems (PEDS) 2017, 343, pp.697-702, Honolulu, Hawaii, USA, 2017-12

• Ayataro Tamura, Koji Kobayashi, Yukinori Tsuruta, Kazuaki Kojima, Hidemine Obara, and Atsuo Kawamura:
  "Range Extension of Electric Vehicles by Two Battery HEECS Chopper based Power Train",
  IEEE Energy Conversion Congress and Exposition (ECCE) 2017，pp.4488-4492, Cincinnati, Ohio, USA, 2017-10

• Makoto Takamiya, Koutaro Miyazaki, Hidemine Obara, Toru Sai, Keiji Wada, and Takayasu Sakurai:
  "Power Electronics 2.0: IoT-Connected and AI-Controlled Power Electronics Operating Optimally for Each User",
  International Symposium on Power Semiconductor Devices and ICs (ISPSD) 2017, pp.29-32, Sapporo, Japan, 2017-6

• Aviti Thadei Mushi, Sakahisa Nagai, Hidemine Obara, and Atsuo Kawamura:
  "Proposal of Nonlinear Current Reference Dead Beat Control for Boost Converter",
  IEEE International Future Energy Electronics Conference (IFEEC) 2017 ECCE-Asia, Kaohsiung, Taiwan, 2017-6

• Toshimitsu Hirai, Hidemine Obara, Shunnosuke Kosuge, and Atsuo Kawamura:
  "Experimental Verification of “Hardware Fail-safe Chopper” for Electrical Wheelchair",
  IEEE International Future Energy Electronics Conference (IFEEC) 2017 ECCE-Asia, Kaohsiung, Taiwan, 2017-6

• Yukihiko Sato, Sae Mochidate, Tomotake Ito, and Hidemine Obara:
  "High Power Density Grid-Connected Converters by Introducing Flying Capacitor Multilevel Topology",
  IEEE International Future Energy Electronics Conference (IFEEC) 2017 ECCE-Asia, Kaohsiung, Taiwan, 2017-6

• Hidemine Obara, Keiji Wada, Koutaro Miyazaki, Makoto Takamiya, and Takayasu Sakurai:
  "Active Gate Control in Half-Bridge Inverter Using Programmable Gate Driver ICs to Improve both Surge Voltage and Switching Loss",
  IEEE Applied Power Electronics Conference and Exposition (APEC) 2017, pp.1153-1159，Tampa, FL, USA, 2017-3

• Sae Mochidate, Kentaro Matsuo, Hidemine Obara, and Yukihiko Sato:
  "A Study on Total Loss Reduction in Motor Drive Systems Based on Flying Capacitor Multilevel Inverter",
  International Conference on Electrical Machines and Systems (ICEMS) 2016, Chiba, Japan, 2016-11

• Toshimitsu Hirai, Hidemine Obara, and Atsuo Kawamura:
  "Hardware Fail-safe Chopper”of DC Motor Drive for Electrical Wheelchair",
  Symposium on Semiconductor Power Conversion (S2PC) 2016, Niigata, Japan, 2016-10

• Hidemine Obara, Kenji Natori, and Yukihiko Sato:
  "Experimental Study on Performance Improvement of Force Control by Using Multi-Level Converters",
  Annual Conference of the IEEE Industrial Electronics Society (IECON) 2015, Yokohama, Japan, 2015-11

• Yukihiko Sato, Miki Iimura, Yuki Dodo, and Hidemine Obara:
  "A Study on Minimum Required Capacitance in Flying Capacitor Multilevel Converters for Grid-Connected Applications",
  IEEE Energy Conversion Congress and Exposition (ECCE) 2015，Montreal, Canada, 2015-9

• Yutaro Ikegami, Hidemine Obara, and Yukihiko Sato:
  "A Study on Device Chip Area Selection of SiC-MOSFETs to Minimize Total Power Loss",
  The 9th International Conference on Power Electronics 2015 -ECCE Asia (ICPE 2015-ECCE Asia)，Seoul, Korea, 2015-6

• Hidemine Obara, Tatsuhito Saito, Kenji Natori, and Yukihiko Sato:
  "A Realization of High-Performance Motion Control Systems by Applying Multi-Level Converters",
  Annual Conference of the IEEE Industrial Electronics Society (IECON) 2014, DD-023191，pp.2656-2662，Dallas, TX, USA, 2014-10

• Hidemine Obara and Yukihiko Sato:
  "Improved Thermal Management of Multi-Level Converter Building Module to Realize Higher Power Density",
  IEEE Energy Conversion Congress and Exposition (ECCE) 2014，P3511, pp.2147-2152，Pittsburgh, Pennsylvania, USA, 2014-9

• Kenji Natori, Hidemine Obara, Kouhei Yoshikawa, Bao Cong Hiu, and Yukihiko Sato:
  "Flexible Power Flow Controller for Next-Generation Multi-Terminal DC Power Network",
  IEEE Energy Conversion Congress and Exposition (ECCE) 2014，P114，pp.778-784，Pittsburgh, Pennsylvania, USA, 2014-9

• Hidemine Obara and Yukihiko Sato:
  "A Theoretical Comparison of Capacitors in Multi-Level Converters",
  2013 Korea-Japan Joint Technical Workshop on Semiconductor Power Converter, IEEJ-SPC-P1-07, pp.79-80, Nagoya, Japan, 2013-10

• Hidemine Obara, and Yukihiko Sato:
  "A Concept of Multi-Level Converter Building Modules to Realize Higher Number of Output Levels",
  IEEE Energy Conversion Congress and Exposition (ECCE) 2013，S105，pp.3042-3048, Denver, Colorado, USA, 2013-9

• Hidemine Obara, Hiroshi Oguri, and Yukihiko Sato:
  "An investigation of harmonics in output voltage of flying capacitor multi-level converters",
  2012 Korea-Japan Joint Technical Workshop on Semiconductor Power Converter，IEEJ-P2-19, pp.198-199, Pohang, Korea, 2012-11

• Hidemine Obara, and Yukihiko Sato:
  "Development of High Power Density Flying Capacitor Multi-level Converters with Balanced Capacitor Voltage",
  IEEE Energy Conversion Congress and Exposition (ECCE) 2012，pp.330-336，Raleigh, North Carolina, USA, 2012-9

• Hidemine Obara, and Yukihiko Sato:
  "Theoretical Analysis of Self-Balancing Function of Capacitor Voltages in Flying Capacitor Multi-level Converters",
  IEEE Energy Conversion Congress and Exposition (ECCE) 2011，pp.2079-2086, Phoenix, Arizona, USA, 2011-9

【Patents】

• Yukihiko Sato, Hidemine Obara, Akira Nakajima, Hiromichi Ohashi, Shinichi Nishizawa：
  "POWER CONVERSION CIRCUIT AND DEVICE"，
  EP Patent, EP3046247A4, 2014-9
  

• Yukihiko Sato, Hidemine Obara, Akira Nakajima, Hiromichi Ohashi, Shinichi Nishizawa：
  "POWER CONVERSION CIRCUIT AND DEVICE"，
  US Patent, 9774241, 2014-9
  

Last Update： 5 Aug. 2024

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