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Affiliation |
Engineering educational research section Electrical and Electronic System Program |
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Title |
Assistant Professor |
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Related SDGs |
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HIRATA Takuya
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Papers 【 display / non-display 】
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Ardhenta L., Hodaka I., Hirata T.
AEU International Journal of Electronics and Communications 206 2026.2
Publishing type：Research paper (scientific journal) Publisher：AEU International Journal of Electronics and Communications
The coupling coefficient as well as the operating frequency increases or decreases the load power in a wireless power transfer system. The parameter space of coupling coefficient and operating frequency is divided into over-, critically-, and under-coupled regions. The load power at over- and under- coupled regions drops from the critically-coupled region where the power is ideally maximized. This situation for series–series topology has been clarified in the conventional studies. In this paper, the critically-coupled region or critical coupling coefficient for series-parallel and parallel-series topologies is revealed in a mathematically form. The results of this paper suggest a selection of topology to improve load power over longer distance in wireless power transfer.
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A cooperative control of wireless power transfer system using two transmitters Reviewed
Hirata T., Hodaka I., Ardhenta L.
Aims Electronics and Electrical Engineering 10 ( 1 ) 129 - 149 2026
Publishing type：Research paper (scientific journal) Publisher：Aims Electronics and Electrical Engineering
A wireless power transfer system with a single transmitter fed by a voltage source and a single receiver with a load is widely studied to increase load power. A system with two transmitters is also studied, especially by controlling currents through transmitter coils to maximize load power, which means current sources to drive transmitter coils are assumed instead of the voltage source. This paper presents a method for adjusting voltage amplitude and phase of each voltage source embedded in two transmitters to maximize load power. The maximized load power is also presented in an explicit form based on circuit constants of the system. As a result, advantages of the two transmitters system over the single transmitter system are revealed from the perspective of efficient power delivery.
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Optimal Wireless Power Transfer Circuit without a Capacitor on the Secondary Side Reviewed
Sabriansyah Rizqika Akbar, Eko Setiawan, Takuya Hirata, Ichijo Hodaka
Energies 16 ( 6 ) 2922 - 2922 2023.3
Publishing type：Research paper (scientific journal) Publisher：MDPI AG
This study proposes an approach to obtain maximum power via wireless power transfer using a single primary-side capacitor. It is shown that higher power is achieved when compared to the common wireless power transfer circuit under resonance with dual (primary- and secondary-side) capacitors. This approach is divided into three phases. By choosing the capacitor and frequency as freely assignable variables, we symbolically obtain a formula that allows us to determine the optimized capacitance and frequency for maximum power. To verify our method, we used a numerical analysis and compared it with an electronic circuit simulation. The symbolic formula is able to maintain maximum power despite changes in load or in the coupling coefficients.
DOI： 10.3390/en16062922
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A Practical Method for Estimating Mutual Inductance in Wireless Power Transmission System Reviewed
Takuto Nakamura, Takuya Hirata, Eko Setiawan, Ichijo Hodaka
International Journal of Circuits, Systems and Signal Processing 16 1027 - 1034 2022
Publishing type：Research paper (scientific journal)
This paper proposes a practical method for estimating mutual inductance in wireless power transmission system based on the principle of electromagnetic induction. Conventional estimation methods utilize a voltage, current, and phase of current in transmitter side, while our method requires only an amplitude of the voltage and current in transmitter side. Our method is designed so that the mutual inductance can be estimated under challenging situation which there is a measurement noise. Numerical simulations show that if the system has a small mutual inductance, a relative error and standard derivation of estimated mutual inductance tend to become larger. However, it will be shown that these factors can be improved to make a voltage of voltage source in the system high.
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The Frequency Response and Steady-State analysis on Wireless Power Transfer using Square Wave Input Reviewed
Sabriansyah Akbar, Eko Setiawan, Takuya Hirata, Kazuya Yamaguchi, Ichijo Hodaka
ACM International Conference Proceeding Series 38 - 43 2021.9
Language：English Publishing type：Research paper (scientific journal) Publisher：Association for Computing Machinery
Finding optimal frequency for the voltage source is important in Wireless Power Transfer (WPT) since it can make the system deliver high power to the receiver. Therefore, it is essential to visualize and analyze the frequency peak locations to ensure the system can use the correct frequency. This paper proposes a model to obtain a set of peaks that lies in some frequency range in a WPT system using square wave input. Thus, using this model, alternatives of peak frequency other than the global peak can be observed. Moreover, this study also proposes the steady-state function of the WPT system. The proposed model and steady-state analysis are compared with the experimental results and Simulation Program with Integrated Circuit Emphasis (SPICE). The comparison verified that the proposed model illustrates the steady-state response and shows the set of peak operating frequency.
Presentations 【 display / non-display 】
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ワイヤレス給電の電力最大化を目的とするオンライン周波数調整法
平田 拓也, 穂高 一条
第44回 計測自動制御学会九州支部 学術講演会 2025.11.29
Event date： 2025.11.29 - 2025.11.30
Presentation type：Oral presentation (general)
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Transferred Power and Topological Structure in Wireless Power Transfer
Lunde Ardhenta, Ichijo Hodaka, Takuya Hirata
2024.12.12
Event date： 2024.12.12
Presentation type：Oral presentation (general)
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On Recognizing Hand-Drawn Electrical Circuit Diagram
Marin Takemoto, Takuya Hirata
The Conference Program of the 2024 （75th） Chugoku-branch Joint Convention of Institutes of Electrical and Information Engineers 2024.10.26
Event date： 2024.10.26
Language：Japanese Presentation type：Oral presentation (general)
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On hidden malfunction of photovoltaic module that is over 20 years passed
Ryuichi Michida, Yuta Okamura, Yusuke Nosaka, Takuya Hirata, Masayuki Fujii, Ikuo Nanno, Toshiyuki Hamada, Shinichiro Oke, Norio Ishikura
2020.10.24
Event date： 2020.10.24
Presentation type：Oral presentation (general)
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Experimental consideration on collection method of micro water droplets in cloud by electrostatic force
Hyogo Matsumura, Akira Nishiyori, Yuma Kunimoto, Takuya Hirata
2020.10.24
Event date： 2020.10.24
Presentation type：Oral presentation (general)