Details of a Researcher - TAKAHASHI Shotaro

TAKAHASHI Shotaro

写真a

Affiliation	Graduate School of Engineering Science Department of Mathematical Science and Electrical-Electronic-Computer Engineering Electrical and Electronic Engineering Course
Homepage URL	https://sites.google.com/view/akitaunivpelab
Mail Address
Special Affairs	TAKAHASHI Shotaro

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Research Interests 【 display / non-display 】

Power electronics
EMI
EMC
Magnetic component

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Graduating School 【 display / non-display 】

2011.04

-

2015.03

Hokkaido University Graduated

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Graduate School 【 display / non-display 】

2017.04

-

2020.03

Hokkaido University Graduate School, Division of Information Science Doctor's Degree Program Completed
2015.04

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2017.03

Hokkaido University Graduate School, Division of Information Science Master's Course Completed

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Degree 【 display / non-display 】

Hokkaido University - Doctor(Engineering)

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Campus Career 【 display / non-display 】

2023.04

-

Now

Akita University Graduate School of Engineering Science Department of Mathematical Science and Electrical-Electronic-Computer Engineering Electrical and Electronic Engineering Course Lecturer

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External Career 【 display / non-display 】

2022.04

-

2023.03

Seikei University Faculty of Science and Technology Department of Science and Technology Assistant Professor
2021.04

　

　

Tokyo Metropolitan University Faculty of System Design Visiting Researcher
2021.04

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2022.04

Seikei University Faculty of Science and Technology Department of Systems Design Engineering Assistant Professor
2020.04

-

2021.03

Tokyo Metropolitan University Faculty of Systems Design Project Assistant Professor

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Academic Society Affiliations 【 display / non-display 】

2020.08

-

Now

Japan

IEICE
2018

-

Now

United States

IEEE
2015.05

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Now

Japan

The Institute of Electrical Engineers in Japan

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Research Areas 【 display / non-display 】

Manufacturing Technology (Mechanical Engineering, Electrical and Electronic Engineering, Chemical Engineering) / Power engineering / Power electronics

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Thesis for a degree 【 display / non-display 】

Study on Suppression Technique of Electromagnetic Noise Produced by High-Speed-Switching Power Converters

Shotaro Takahashi

2020.03

Single author

DOI

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Research Achievements 【 display / non-display 】

◆Original paper【 display / non-display 】

Simulation Study of the Small-Signal Characteristics of Single-Phase Common-Mode Inductors with Capacitance Cancellation

Shotaro Takahashi

Applied Sciences ( MDPI ) 14 ( 3 ) 2024.01 [Refereed]

Research paper (journal) Single author

This article proposes a simulation model of single-phase common-mode inductors to evaluate the small-signal characteristic of common-mode inductors when the stray capacitance cancellation method is applied. From the estimated stray capacitance of common-mode inductors, the value of the cancellation capacitors is determined and implemented into the model. Thus, the proposed model can simulate the small-signal characteristic of common-mode inductors with the capacitance cancellation method at the design stage. To validate the proposed model, a comparison between measured and simulated attenuation characteristics of fabricated single-phase common-mode inductors is performed. The comparison result clarifies that the high-frequency attenuation improvement of the capacitance cancellation method is limited for manganese–zinc ferrite-based common-mode inductors due to the steep change of the complex permeability.

DOI

Simulation-Based Design of the Common-Mode Transformer-Less Hybrid EMI Filter in DC-Fed Motor Drive Systems

Shotaro Takahashi

IEEE Access ( IEEE ) 11 134485 - 134494 2023.12 [Refereed]

Research paper (journal) Single author

This article presents a circuit simulation-based design method for common-mode (CM) transformer-less hybrid EMI filters (HEFs) to obtain the required CM current attenuation. First, a simulation-based design method of the HEF, including the passive filtering components, is presented. The prototype HEF is implemented in a DC-fed three-phase motor drive system to validate the design method and evaluate the HEF’s performance. The measured results validate the presented design method and show that the HEF can increase the CM current attenuation of a passive EMI filter (PEF) up to 8.2 dB in the frequency range from 100 kHz to 1.4 MHz. Furthermore, the measured result clarifies that implementing a voltage-sensing parallel-compensating active feedback circuit can reduce the volume of the CMI used in a PEF designed to achieve the same attenuation of the HEF by about 75 %.

DOI

Experimental Study of Radiated Emission Due to Secondary Common-Mode Current in Buck Converters

Shotaro Takahashi

Applied Sciences ( MDPI AG ) 13 ( 21 ) 11735 - 11735 2023.10 [Refereed]

Research paper (journal) Single author

High switching frequency and fast switching speed of wide bandgap power semiconductor device-based power converters may increase radiated emissions more than conventional silicon-power device-based power converters. Based on the background, this article experimentally investigates radiated emission sources in buck converters. The experimental system constructed in this article has two common-mode noise paths, the primary common-mode and the secondary common-mode. First, this article outlines that a secondary common-mode voltage source is caused by a primary common-mode current and an imbalance of power supply side impedances, and the secondary common-mode current path acts as a monopole antenna. The common-mode currents and the radiated emissions are measured in an anechoic chamber when the common-mode inductor for each mode is connected. The measurement results show that the primary common-mode current generates the secondary common-mode noise, and the secondary common-mode noise is the dominant source of radiated emission in the experimental system.

DOI

Experimental Investigation of the Dimensional Effect on Small-Signal Characteristics of Common-Mode Inductors

Shotaro Takahashi

IEEE Access ( Institute of Electrical and Electronics Engineers (IEEE) ) 10 123068 - 123079 2022.11 [Refereed]

Research paper (journal) Single author

Due to their high permeability and high effective permittivity, manganese zinc (MnZn) ferrites exhibit magnetic resonance depending on the core dimension. Once magnetic resonance occurs, the relative permeability of MnZn ferrites decreases drastically in the high-frequency (HF) range. The decrease in the relative permeability can influence the HF noise reduction performance of common-mode inductors (CMIs). Based on the above, this study experimentally investigates the impact of the dimensional effect of MnZn ferrites on the small-signal characteristics of CMIs. First, the CM small-signal characteristics of CMIs with different core dimensions indicated that the dimensional effect of MnZn ferrites decreases the CM impedances of the CMIs in the HF range. Two types of core division (air gap insertion and core lamination) were applied to the core to mitigate the dimensional effect on the CM impedances of the CMIs. The influence of the core divisions on the complex permeabilities and the small-signal characteristics of the CMIs were evaluated based on the experimental results. The measurement results clarified that core lamination might be the appropriate option in EMI filtering applications because it can mitigate the dimensional effect and increase the CM impedance of CMIs in the HF range without increasing the number of turns.

DOI

Attenuation Characteristics of the Input/Output Coupling Passive EMI Filter on Conducted Emission in Motor Drive Systems

Shotaro Takahashi, Sari Maekawa

IEEJ Journal of Industry Applications ( IEEJ ) 11 ( 5 ) 2022.05 [Refereed]

Research paper (journal)

The authors propose an input/output coupling passive electromagnetic interference filter (PEF) for motor drive systems. The input/output coupling PEF uses magnetic coupling and integrates the common-mode inductors connected to the input and output sides of an inverter into a single magnetic component. Hence, this study investigates the attenuation characteristics of the input/output coupling PEF on conducted emission in motor drive systems. The measured results show that the input/output coupling PEF increases the attenuation of conducted emission compared to conventional PEFs over a broad range of frequencies.

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◆International conference proceedings【 display / non-display 】

Permeance-Capacitance Analogy-Based Wideband Small-Signal Model of Three-Phase Common-Mode Inductors

Shotaro Takahashi, Keiji Wada

IECON Proceedings (Industrial Electronics Conference) ( IECON Proceedings (Industrial Electronics Conference) ) 2023.10 [Refereed]