研究者データベース

折川 幸司(オリカワ コウジ)
情報科学研究院 システム情報科学部門 システム融合学分野
助教

基本情報

所属

  • 情報科学研究院 システム情報科学部門 システム融合学分野

職名

  • 助教

学位

  • 博士(工学)(長岡技術科学大学)

ホームページURL

科研費研究者番号

  • 50781324

ORCID ID

J-Global ID

研究キーワード

  • パワーエレクトロニクス   

研究分野

  • ものづくり技術(機械・電気電子・化学工学) / 電力工学

職歴

  • 2016年04月 - 現在 北海道大学 助教
  • 2013年04月 - 2016年03月 長岡技術科学大学 電気系 パワーエレクトロニクス研究室 産学官連携研究員

学歴

  • 2010年04月 - 2013年03月   長岡技術科学大学大学院   工学研究科   エネルギー・環境工学専攻 博士後期課程
  • 2008年04月 - 2010年03月   長岡技術科学大学大学院   工学研究科   電気電子情報工学専攻 修士課程
  • 2006年04月 - 2008年03月   長岡技術科学大学   工学部   電気電子情報工学課程
  • 2001年04月 - 2006年03月   八戸工業高等専門学校   電気工学科

所属学協会

  • 電気学会   

研究活動情報

論文

  • 高橋 翔太郎, 小笠原 悟司, 竹本 真紹, 折川 幸司, 玉手 道雄
    電気学会論文誌D(産業応用部門誌) 140 6 433 - 441 一般社団法人 電気学会 2020年 [査読有り][通常論文]
     

    This study investigates the relationship between filter inductor impedance and dimensional resonance of MnZn ferrite. Experimental results clarify that multiple factors affect inductor impedance resonances. These can be classified into three factors: the inherent characteristics of a magnetic material, self-resonance due to winding stray capacitance, and winding that acts as a distributed constant line. Next, based on the measurement results, the dimensional dependencies of complex permeabilities (dimensional resonance) and the influence of dimensional resonance on inductor impedance are discussed in detail. Finally, this study verifies that the influence of dimensional resonance on complex permeability can be mitigated, and filter inductor impedance can be increased in the high frequency range by core lamination. All experiments are performed using off-the-shelf magnetic core products.

  • Shotaro Takahashi, Satoshi Ogasawara, Masatsugu Takemoto, Koji Orikawa, Michio Tamate
    2019 IEEE 4th International Future Energy Electronics Conference, IFEEC 2019 2019年11月 [査読有り][通常論文]
     
    © 2019 IEEE. This paper explores the relationship between filter inductor impedance and dimensional resonance in magnetic cores. Experimental results were obtained showing multiple factors behind the resonances that appear in the frequency characteristics of inductor impedances: the inherent characteristics of a magnetic material, the self-inductance of an inductor and stray capacitance in its winding, and the winding acting as a distributed constant line. Next, based on the measurement results, the dimensional dependencies of the complex permeabilities (dimensional resonance) and the influence of dimensional resonance on inductor impedance are discussed in detail. Finally, this paper shows that the effect of dimensional resonance on complex permeability can be mitigated and filter inductor impedance can be increased in the high frequency range by a core lamination. These results are verified by the experiments described in this paper.
  • Hwang Soonhwan, Ogasawara Satoshi, Orikawa Koji, Takemoto Masatsugu
    IEEJ TRANSACTIONS ON ELECTRICAL AND ELECTRONIC ENGINEERING 14 5 780 - 791 2019年05月 [査読有り][通常論文]
  • Shotaro Takahashi, Satoshi Ogasawara, Masatsugu Takemoto, Koji Orikawa, Michio Tamate
    IEEE Transactions on Industry Applications 55 3 2721 - 2730 2019年05月 [査読有り][通常論文]
     
    © 1972-2012 IEEE. The switching speeds of next-generation power semiconductor devices, such as those made of silicon carbide and gallium nitride are roughly ten times those of conventional devices (e.g., silicon insulated-gate bipolar transistors). This increases the frequency range of the electromagnetic noise accompanying the switching operations of pulsewidth modulated (PWM) converters and worsens the influence of radiated noise. The authors have previously proposed an active common-mode filter (ACF) that reduces the radiated noise from the power cables connected to a PWM converter and evaluated its effect in reducing radiated noise by using a function generator as a common-mode (CM) noise source. In this paper, the ACF is applied to a motor drive system fed by a three-phase PWM inverter, and the attenuation characteristics of the CM voltage are evaluated. To avoid saturating the ACF, the combination of an active common-noise canceller and the ACF is discussed. The experimental results show that the system constructed in this paper can suppress the CM voltage produced by the PWM inverter over a wide frequency range from 100 to 100 MHz.
  • Koji Orikawa, Satoshi Ogasawara, Masatsugu Takemoto, Jun-ichi Itoh
    6603 - 6608 2019年
  • Shotaro Takahashi, Satoshi Ogasawara, Masatsugu Takemoto, Koji Orikawa, Michio Tamate
    2019 IEEE ENERGY CONVERSION CONGRESS AND EXPOSITION (ECCE) 2859 - 2866 2019年 [査読有り][通常論文]
     
    High switching speed in next-generation power devices such as silicon carbide allows increased switching frequencies in power converters. Higher switching frequencies increase power densities, but also increase frequencies of electromagnetic noise accompanying switching operations, resulting in more serious electromagnetic interference (EMI). Radiated EMI will thus soon become a major concern when developing power converters. Most previous works have focused on conducted EMI, resulting in a dearth of research on radiated EMI from power converters. We thus investigated the generation mechanism of radiated noise from power converters to identify effective reduction methods. We identify two propagation paths of high-frequency (HF) common-mode (CM) noise currents, primary CM (PCM) and secondary CM (SCM). SCM constructs a large propagation loop, thus becoming a major source of radiated noise. To suppress HF CM current flow through each mode, we fabricate two types of CM inductors (CMI). HF CM currents are measured in a simple buck converter system. CM current measurements verify the effectiveness of CMI for reduction of HF CM currents and clarify how SCM voltage source is generated. The described generation mechanism of SCM voltage source and radiated noise is verified by measurements of radiated noise in a fully anechoic chamber.
  • Orikawa Koji, Kinomae Takeshi, Itoh Jun-ichi
    IEEJ JOURNAL OF INDUSTRY APPLICATIONS 8 1 12 - 22 2019年 [査読有り][通常論文]
  • 高橋翔太郎, 小笠原悟司, 竹本真紹, 折川幸司, 玉手道雄
    電気学会論文誌 D 139 3 339 - 347 2019年 [査読無し][通常論文]
     
    © 2019 The Institute of Electrical Engineers of Japan. The switching speed of next-generation power devices based on wide-bandgap semiconductors, such as silicon carbide (SiC) and gallium nitride (GaN), are more than ten times those of conventional silicon insulated-gate bipolar transistors (Si-IGBT). This may increase the frequency range of electromagnetic noise produced by pulse-width-modulated converters. Further, the operating frequency ranges of noise filters are limited by the parasitic components of passive elements, so it is difficult to realize a high-frequency (HF) noise filter whose operating frequency exceeds several tens of megahertz. This paper proposes a novel and simple analytical method to calculate the winding stray capacitance of an HF three-phase common-mode (CM) inductor for the purpose of estimating its operating frequency range at the design stage. Results of measuring the CM impedance confirm that the proposed method can estimate the operating frequency range of an HF three-phase CM inductor while ensuring practically sufficient precision. Furthermore, the obtained results also show that the reduction in the number of turns does not always contribute to the enhancement of the operating frequency ranges of filter inductors.
  • Shotaro Takahashi, Satoshi Ogasawra, Masatsugu Takemoto, Koji Orikawa, Michio Tamate
    2018 IEEE Energy Conversion Congress and Exposition, ECCE 2018 6600 - 6606 2018年12月03日 [査読有り][通常論文]
     
    © 2018 IEEE. Switching speed of the next-generation power devices based on the wide-bandgap semiconductors such as silicon carbide and gallium nitride are more than ten times faster than the conventional silicon insulated-gate bipolar transistors. This may increase frequency ranges of electromagnetic noise accompanied by switching operations of power converters. Besides, the operating frequency ranges of noise filters are limited due to frequency dependencies of magnetic materials and parasitic components of passive components, thus, the realization of the high-frequency (HF) noise filter with the operating frequency range beyond several ten megahertz is difficult. This paper presents a modeling technique for estimating the operating frequency range of the HF three-phase common-mode (CM) inductors. The proposed method includes a novel simple estimation technique of winding stray capacitance. The CM impedance measurement results validate that the proposing model can estimate the operating frequency range of the HF three-phase CM inductor while securing practically sufficient precision at the design-stage.
  • 提橋郁人, 伊東淳一, 折川幸司
    電気学会論文誌 D 138 1 30 - 38 2018年 [査読無し][通常論文]
     
    This paper investigates a switching operation when a current-source gate drive circuit is used for large gate capacitance. The current-source gate drive circuit consists of a voltage source, an input inductor, and switching devices such as an H-bridge inverter. The power consumption of this circuit is reduced in comparison with that of a conventional voltage source gate drive circuit because the energy of the capacitor between a gate and a source is not consumed in gate resistance, which is not required for the current source gate drive circuit. The switching operation of the proposed current source gate drive circuit in the high-frequency inverter is evaluated experimentally. In addition, the power consumption is measured when the switching frequency is changed from 100 kHz to 1 MHz. As a result, it is confirmed that the power consumption of the current-source gate drive circuit is reduced by 62% compared with that of the voltage source gate drive circuit at 1MHz.
  • Shunsuke Ohara, Satoshi Ogasawara, Takemoto Masatsugu, Koji Orikawa, Yushin Yamamoto
    2017 IEEE Energy Conversion Congress and Exposition, ECCE 2017 2017- 2469 - 2475 2017年11月03日 [査読有り][通常論文]
     
    This paper proposes a novel type of an active common noise canceler (ACC) combining feedforward and feedback control. The ACC attenuates the common-mode (CM) voltage and suppresses EMI emissions by adding the CM voltage of reverse polarity to the CM voltage generated by inverters in AC motor drive system. The proposed ACC uses feedforward and feedback control whereas the original ACC [19] uses feedforward control only. Experimental evaluation is presented for comparison between the proposed ACC, a feedforward ACC, and commonmode chokes (CMCs) which are widely used as passive filters. The experimental results show that the proposed ACC has large CM voltage attenuation of up to 50 dB in the wide frequency range. The attenuation performance of the proposed ACC is larger than the feedforward ACC and a CMC, which uses the same ferrite core and windings used in the proposed ACC.
  • Yu Fu, Masatsugu Takemoto, Satoshi Ogasawara, Koji Orikawa
    2017 IEEE International Electric Machines and Drives Conference, IEMDC 2017 2017年08月03日 [査読有り][通常論文]
     
    Bearingless motors (BelMs), which can realize magnetic levitation rotation with no mechanical contact, have been proposed and developed. In general, in high speed and high output BelMs, distributed winding structure is adopted in order to suppress iron loss, and neodymium sintered permanent magnet (Nd sintered PM) is employed to achieve a high power density. However, output power fall is caused due to long coil end of the distributed winding structure because a shaft length is limited by primary bending mode under high speed rotation. Furthermore, eddy current loss easily occurs in the Nd sintered PM because of its high conductivity. It is difficult to achieve continuous high-speed and high-output operation due to the temperature raising in a rotor. Therefore, in this paper, a high speed and high power density BelM using concentrated winding stator and neodymium bonded permanent magnet (Nd bonded PM) is proposed in order to suppress output power reduction caused by the coil end and eddy current loss generated in PM. In addition, this paper indicates analysis results of various BelM models using distributed winding structure, concentrated winding structure, Nd sintered PM, and Nd bonded PM, respectively. Comparison of these results is discussed in detail and effectiveness of the proposed structure is clarified.
  • Shotaro Takahashi, Satoshi Ogasawara, Koji Orikawa, Masatsugu Takemoto, Michio Tamate
    2017 IEEE 3rd International Future Energy Electronics Conference and ECCE Asia, IFEEC - ECCE Asia 2017 1753 - 1758 2017年07月25日 [査読有り][通常論文]
     
    © 2017 IEEE. Power electronics equipments can cause serious electromagnetic interference (EMI) because of their high-speed switching. Such switching disturbances then propagate along power cables, which can act as antennas to radiate the noise. Typically, a passive filter composed of inductors and capacitors is widely used to reduce electromagnetic interference. However, when a power cable is connected to the passive filter, the cable acts as a distributed line that worsens the attenuation characteristic of the passive filter at the anti-resonant frequencies of the cable. This paper proposes a solution to this problem in the form of an active common-mode filter (ACF) that uses a high-speed amplifier. Experimental results show that the proposed filter improves the attenuation characteristics of the passive filter and reduces the common-mode voltage propagating through the cable over a wide range of frequencies from 10 MHz to 100 MHz. Furthermore, measurements for radiated noise from the cable are carried out in an anechoic chamber, and evaluate the radiated noise attenuation characteristics of the ACF.
  • Koji Orikawa, Satoshi Ogasawara, Jun-Ichi Itoh
    PCIM Europe 2017 - International Exhibition and Conference for Power Electronics, Intelligent Motion, Renewable Energy and Energy Management 2017年 [査読有り][通常論文]
     
    This paper describes a 2.5 MHz high frequency inverter based on a frequency multiplying method. A proposed circuit consists of a five-phase inverter and multi-core transformers. An operation frequency of the five-phase inverter and multi-core transformer is 500 kHz which is one-fifth of an output frequency of 2.5 MHz. Therefore, the proposed circuit can realize high efficiency by utilizing available semiconductor switches and magnetic materials. In this work, a principle of suppression of iron loss is experimentally clarified by measuring B-H curves of a single transformer without a load when sinusoidal voltage is applied. Next, power losses of semiconductor switch and multi-core transformer are formulated. Finally, a power loss distribution is clarified based on theoretical analysis and the measured efficiency of the prototype circuit.
  • Hoai-Nam Le, Koji Orikawa, Jun-ichi Itoh
    IEEE Trans. Ind. Electron. 64 2 1157 - 1166 2017年 [査読有り][通常論文]
     
    This paper proposes a current control method for discontinuous current mode (DCM) in order to achieve the same control performance as continuous current mode (CCM) in a boost converter. By utilizing the duty ratio at the previous calculation period to compensate for a DCM nonlinearity, the controller, which is designed for CCM, can also be used in DCM. In the frequency analysis, the cutoff frequency of the proposed DCM current control agrees exactly to the design value, which is 2 kHz, whereas the cutoff frequency of the conventional DCM current control results in high error of 47.5%. In the current step response experiment with a 360-W prototype and the switching frequency of 20 kHz, the experimental DCM current response almost agrees with the conventional CCM current response, which are 380-mu s rise time for both CCM and DCM, 9% and 8% overshoot for CCM and DCM, respectively. Furthermore, the computation time of the proposed DCM current control is shorter 35% than the conventional DCM current control.
  • 高橋翔太郎, 小笠原悟司, 竹本真紹, 折川幸司, 玉手道雄
    電気学会論文誌 D 137 8 639 - 646 2017年 [査読無し][通常論文]
     
    © 2017 The Institute of Electrical Engineers of Japan. Power electronics devices can cause serious electromagnetic interference (EMI) because of their high-speed switching. Such switching disturbances then propagate along power cables, which can act as antennas to radiate noise. Typically, a passive filter composed of inductors and capacitors is used to reduce EMI. However, when a power cable is connected to the passive filter, the cable acts as a distributed constant line that worsens the attenuation characteristic of the passive filter at the anti-resonant frequencies of the cable. This study proposes a solution to this problem in the form of an active common-mode filter that uses a high-speed amplifier. Experimental results show that the proposed filter improves the attenuation characteristics of the passive filter and reduces radiated noise from the cable over a wide range of frequencies from 10MHz to 100 MHz.
  • Asmarashid Bin Ponniran, Koji Orikawa, Junichi Itoh
    IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS 52 4 3255 - 3266 2016年07月 [査読有り][通常論文]
     
    This paper proposes a multilevel flying capacitor dc/dc boost converter (FCBC) with a small capacitance of the flying capacitor for the reduction of converter size. In this paper, the design methods for the boost inductor and the flying capacitor in the n-level FCBC are principally and experimentally confirmed. Furthermore, the boost inductor is designed based on maximum product of voltage-time, regardless the number of level. Meanwhile, the minimum capacitance of the flying capacitor is designed based on the maximum switching device voltage stress, regardless of the output voltage ripple influences. Moreover, the achieved maximum efficiency of the designed three-level FCBC is 98.5% at the output power of 1 kW. Finally, the effectiveness of small capacitances of the flying capacitor in the three-level and five-level FCBCs is analyzed. The characteristics of the distorted voltage across the input voltage source and the boost inductor, and the distorted current to the output side (output capacitor and load) are investigated with several capacitances of the flying capacitors in the three-level and five-level FCBCs. As a result, it is experimentally confirmed that the distorted voltage is drastically reduced by increasing the number of level. Besides, the distorted current is almost the same although the number of level is increased. Therefore, based on the experimental results, it is shown that small capacitance of the flying capacitor can be used in the n-level FCBC without compromising the stability of converter operation.
  • Ayato Sagehashi, Koji Orikawa, Jun-ichi Itoh
    2016 IEEE 8TH INTERNATIONAL POWER ELECTRONICS AND MOTION CONTROL CONFERENCE (IPEMC-ECCE ASIA) 2016年 [査読有り][通常論文]
     
    This paper investigates a switching operation when a current source gate drive circuit with energy cycling is used. The current source gate drive circuit consists of a voltage source, an input inductor and switching devices as an H- bridge inverter. The power consumption of the current source gate drive circuit is reduced to compared with that of a conventional voltage source gate drive circuit because the energy of the capacitor between a gate and a source is not consumed in a gate resistance which is not required for the current source gate drive circuit. The switching operation of the proposed current source gate drive circuit in the high frequency inverter is evaluated in experiment. In addition, the power consumption is measured when the switching frequency is changed from 100 kHz to 1 MHz. As a result, it is confirmed that the power consumption of the current source gate drive circuit with energy cycling is reduced by 26% compared with that of the voltage source gate drive circuit at 1 MHz. In addition, the differential configuration of the current source gate drive circuit is considered in order to actualize the regenerating energy. Consequently, the regenerating energy of the inductor and the capacitance between a gate and a source is confirmed on the proposed current source gate drive circuit in simulation.
  • Hoai Nam Le, Koji Orikawa, Jun-ichi Itoh
    2016 IEEE 17th Workshop on Control and Modeling for Power Electronics (COMPEL) 2016年 [査読有り][通常論文]
     
    This paper proposes a hybrid current mode between Triangular current mode (TCM) and Discontinuous current mode (DCM) in order to achieve Zero-voltage switching (ZVS) for a bidirectional buck/boost DC-DC converter. In the proposed Hybrid Discontinuous Current Mode entitled HDCM, the TCM operation is applied during the zero-current interval of DCM. Therefore, both ZVS and the variable current ripple, which result in the high efficiency at wide load range, are achieved. The achievement of ZVS with HDCM is confirmed by a 600-W prototype. Compared to TCM, the Root-Mean-Square current is reduced by 47.2% at most with HDCM, which further contributes to the loss reduction. Moreover, under the condition of the same boost inductor, the efficiency of HDCM at load of 0.2 p.u. is improved by 1.5% compared to TCM.
  • Hiroki Watanabe, Keisuke Kusaka, Keita Furukawa, Koji Orikawa, Jun-ichi Itoh
    APEC 2016 31ST ANNUAL IEEE APPLIED POWER ELECTRONICS CONFERENCE AND EXPOSITION 1336 - 1343 2016年 [査読有り][通常論文]
     
    A novel power decoupling circuit using a flying capacitor topology is proposed in this paper. The inverters, which are connected to a single-phase grid, have single-phase power fluctuation at the twice the grid frequency. Thus, bulky electrolytic capacitor is generally used as DC link capacitor. In the proposed circuit, the power fluctuation is compensated by the flying capacitor in the flying capacitor DC-DC converter. The proposed circuit does not need an additional magnetic component in comparison with the conventional system, which has a boost chopper and an inverter. The proposed converter is experimentally tested with a 1-kW prototype. A voltage ripple at twice the frequency on the inverter DC voltage is suppressed from 35.1% to 4.6%. Moreover, the maximum efficiency of 94.5% with an output power of 1.0 kW is achieved. Finally, the design method of the boost-up inductor for proposed circuit is estimated by experiment. As a result, the error of the ripple current between design and measurement value is 4.7%.
  • Satoshi Nagai, Hoai Nam Le, Tsuyoshi Nagano, Koji Orikawa, Jun-ichi Itoh
    2016 IEEE 8TH INTERNATIONAL POWER ELECTRONICS AND MOTION CONTROL CONFERENCE (IPEMC-ECCE ASIA) 2016年 [査読有り][通常論文]
     
    When a inductance of a single-phase grid-connected inverter is minimized, the effect of the disturbance to the current control such as the dead-time error voltage increases. This paper proposes a disturbance compensation method by using a high-performance disturbance observer. In particular, in the control system, the current controller is implemented by the digital signal processor, whereas the high-performance disturbance observer is implemented by the field-programmable gate array in order to suppress the disturbance at high switching frequency. This results in the improvement of the current control performance. With the experimental prototype, in case of the minimized inductance (% Z = 0.5%), the total harmonic distortion (THD) of the output current is improved from 11.1% to 2.9% at rated load by applying the proposed disturbance compensation method. Furthermore, with the proposed disturbance compensation method, it is confirmed that THD of the output current is improved by over 68% at all load range.
  • Keisuke Kusaka, Koji Orikawa, Jun-Ichi Itoh, Isamu Hasegawa, Kazunori Morita, Takeshi Kondo
    IEEJ Journal of Industry Applications 5 3 206 - 214 2016年 [査読有り][通常論文]
     
    In this paper, a gate driver supply, which supplies power to multiple gate drivers, is demonstrated. Robust isolation is required in the gate drive supplies of a medium-voltage inverter in order to drive high-voltage switching devices such as insulated-gate bipolar transistors. The proposed isolation system achieves isolation with transmission coils mounted on printed circuit boards. Furthermore, the isolation system transmits power from one transmitting board to six receiving boards. In the conventional system, the number of receivers is limited to one. In contrast, multiple receivers are acceptable in the proposed system. These characteristics help reduce the of the isolation system for the gate driver supplies. This paper presents the fundamental characteristics of the isolation system. The equivalent circuit of the proposed system can be derived by applying the equivalent circuit of a wireless power transfer system with a repeater coil. In addtion, a design method for the resonance capacitors is mathematically introduced using the equivalent circuit. It is verified that an isolation system with multiple receivers can be designed using the same resonance conditions as an isolation system with a single receiver. Moreover, the isolation system is experimentally demonstrated. It is confirmed that the isolation system transmits power with a maximum efficiency of 46.9% at an output power of 16.6Wbeyond an air gap of 50mm with only printed circuit boards.
  • Asmarashid Bin Ponniran, Koji Orikawa, Jun-Ichi Itoh
    IEEJ Journal of Industry Applications 5 1 10 - 11 2016年 [査読有り][通常論文]
     
    In this paper, we propose a minimization design method of the inductance and the capacitance of the flying capacitors for a multi-level flying capacitor DC-DC boost converter (FCBC). The effectiveness of the small capacitances of the flying capacitors in three-level and five-level FCBCs is investigated. We experimentally confirmed that the distortion of the voltage across the input source and the input inductor is drastically reduced by increasing the number of levels. Thus, a small inductance value and a small capacitance value can be used for the input inductor and the flying capacitors, respectively, in an n-level FCBC. Therefore, the minimization of passive components in multi-level FCBCs is achieved. Moreover, the achieved maximum efficiencies of the designed three-level and five-level FCBCs are 98.5% and 97.8%, respectively, at an output power of 1 kW.
  • Asmarashid Bin Ponniran, Koji Orikawa, Jun-Ichi Itoh
    IEEJ Journal of Industry Applications 5 4 329 - 338 2016年 [査読有り][通常論文]
     
    The paper proposes a Marx topology DC-DC boost converter (MTBC) with a high boot ratio, where a parallel connection is applied on the input side in order to reduce the conduction and copper losses while a series connection is applied on the output side in order to reduce the voltage stress on switching devices. With the proposed circuit configuration, the high boost ratio DC-DC converter achieves high efficiency. A three-stage MTBC with a boost ratio of 8.33 between the input and output voltages was designed and constructed. A maximum efficiency of 94.5% was achieved with the designed three-stage MTBC. The loss analysis showed that the iron and conduction losses were dominant. The volume analysis showed that the proposed three-stage MTBC requires approximately 23% less of a total volume compared to the conventional isolated DC-DC converter with a two-series-output-rectifier (ICSR) while reducing the power loss of semiconductor devices.
  • 伊東淳一, 野口健二, 折川幸司
    電気学会論文誌 D 135 12 1225 - 1236 2015年12月01日 [査読無し][通常論文]
     
    This paper presents a wireless charging system that utilizes an electric double layer capacitor (EDLC) as a power source for an electric assisted bicycle. The proposed system was optimized in terms of miniaturization. First, the minimum energy of the EDLC was evaluated. The results showed that the energy source in the proposed system can be smaller than that in the conventional system when the energy density of the EDLC is improved more than 1.52 times. Second, the coil of the wireless power transmission and the charger were analyzed. Short- and open-type coils of the same size were compared in experiments. The results showed that the short-type coil can be further miniaturized than the open-type coil at the same resonance frequency. Third, the volumes of the EDLC and converter were evaluated. The results showed that the volume of the boost type can be reduced by 30% compared to that of the buck type. Finally, in order to reduce the number of devices in the proposed system, the diode bridge rectifier was replaced with a three-phase inverter. This reduced the number of devices of the proposed system by one-third.
  • Kusaka Keisuke, Kato Masakazu, Orikawa Koji, Itoh Jun-ichi, Hasegawa Isamu, Morita Kazunori, Kondo Takeshi
    2015 IEEE Energy Conversion Congress and Exposition (ECCE) 2015年10月 [査読有り][通常論文]
  • J. Itoh, T. Aaraki, K. Orikawa
    IEEJ Journal of Industry Applications 4 3 212 - 219 IEEJ 2015年03月01日 [査読有り][通常論文]
  • Asmarashid Ponniran, Koji Orikawa, Jun-ichi Itoh
    2015 9TH INTERNATIONAL CONFERENCE ON POWER ELECTRONICS AND ECCE ASIA (ICPE-ECCE ASIA) 1289 - 1296 2015年 [査読有り][通常論文]
     
    This paper proposes a Flying Capacitor DC/DC Boost Converter (FCBC) with a small capacitance of the flying capacitor. As a result the size and weight of the proposed converter can be reduced. The capacitance of the flying capacitor is designed based on switching device voltage rating and regardless of the output voltage ripple influences. Moreover, the achieved maximum efficiency of the designed 3-level FCBC is 98.5% at the output power of 1 kW. Finally, the effectiveness of small capacitances of the flying capacitor in the 3-level and 5-level FCBCs are investigated. The characteristics of the distorted voltage across an input voltage source and an input inductor and the distorted current to the output side which is an output capacitor and a load are investigated with several capacitances of the flying capacitors for 3-level and 5-level FCBCs. As a result, it is experimentally confirmed that the distortion of the voltage across the input voltage source and the input inductor is drastically reduced by increasing the number of level. On the other hand, the distortion of the current to the output side which is the output capacitor and the load is almost same even the number of level is increased. Therefore, the experimental results show that small capacitance of the flying capacitor can be used in the n-level FCBC.
  • Asmarashid Ponniran, Koji Orikawa, Jun-ichi Itoh
    2015 IEEE INTERNATIONAL TELECOMMUNICATIONS ENERGY CONFERENCE (INTELEC) 2015年 [査読有り][通常論文]
     
    The paper proposes a high boost ratio of modular Marx topology DC-DC boost converter (MTBC). In the proposed converter, the parallel-connection is applied at the input side and multi-stage connection is applied at the output side. Then, the conduction loss and the voltage rating of switching components can be reduced. Therefore, with the proposed circuit configuration, high efficiency of the high boost ratio DC-DC converter is achieved. The efficiency is measured under various input voltages. As a result, the achieved maximum efficiency of the prototype 3-stage MTBC is 95% when the output power is 500 W.
  • Hoai Nam Le, Daisuke Sato, Koji Orikawa, Jun-ichi Itoh
    2015 17TH EUROPEAN CONFERENCE ON POWER ELECTRONICS AND APPLICATIONS (EPE'15 ECCE-EUROPE) 2015年 [査読有り][通常論文]
     
    This paper proposes a feedback current control for bidirectional DC-DC converter which is operated in Discontinuous Current Mode (DCM) at light load and Continuous Current Mode (CCM) at heavy load in order to improve light load efficiency. In the proposed method, the nonlinearity compensation for DCM operation is constructed by using the duty ratio at previous calculation period. Moreover, the introduction of DCM current feedback control into bidirectional power conversion is accomplished by detecting the operation mode at the output of the control system. This make the control becomes parameter-independent. The validity of the proposed control is confirmed by a 1-kW prototype. In the ramp response, the slope of the DCM current almost agrees to the design value with the error of 0.8%. Moreover, the smooth transition among 4 current modes: CCM-powering, DCM-powering, DCM-generation, CCM-generation, is also confirmed. On the other hand, in order to further improve the efficiency at light load, the synchronous switching for DCM is proposed. As a result, at load of 0.1 p.u. the efficiency of the DCM synchronous switching is improved by 1.5% from 97.2% to 98.7% compared with the CCM synchronous switching. Besides, it is confirmed that, the efficiency of the CCM/DCM synchronous switching is higher by 0.2% than that of the CCM/DCM asynchronous switching at all range of load. Furthermore, the efficiency at rated load is 98.8%, whereas the maximum efficiency is 99.0% at load of 0.45-0.65 p.u..
  • T. Nagano, K. Orikawa, J. Itoh, A. Toba
    2015 9TH INTERNATIONAL CONFERENCE ON POWER ELECTRONICS AND ECCE ASIA (ICPE-ECCE ASIA) 337 - 344 2015年 [査読有り][通常論文]
     
    This paper proposes an approach to simplify the proposed halt sequence of an inverter without the pole position information of a permanent magnet synchronous motor. When the Back-to-back (BTB) system with a small capacitor is stopped by the grid faults during motor regeneration, the DC-link capacitor voltage is increased rapidly if all gates in the BTB system are turned off at the same time. Therefore, a dynamic brake system is connected in parallel to the DC-link capacitor. The proposed halt sequence can stop the regeneration operation and suppress the rising of the DC-link capacitor voltage without the dynamic brake system. The proposed halt sequence is simplified by detecting the peak of the maximum current in this paper. In the experiment, it is confirmed that proposed halt sequence without the pole position information suppresses the rising of the DC-link capacitor voltage within 12V as well as with the pole position information.
  • Koji Orikawa, Jun-ichi Itoh
    2015 IEEE 2ND INTERNATIONAL FUTURE ENERGY ELECTRONICS CONFERENCE (IFEEC) 2015年 [査読有り][通常論文]
     
    This paper discusses a verification of an inverter outputs MHz frequency which is over the switching frequency. The proposed inverter consists of a multi-phase inverter using silicon switching devices and multi-core transformers. By the frequency multiplying, high switching frequency compared with the output frequency is not required. Moreover, the series resonance using a leakage inductance of the multi-core transformers and a resonant capacitor is applied in order to achieve sinusoidal output voltage. A prototype circuit is experimentally verified and theoretically analyzed in terms of zero voltage switching (ZVS). As a result, it is confirmed that the prototype circuit can output sinusoidal output voltage of 2.5 MHz with the switching frequency of 500 kHz. In addition, a required dead time for zero voltage switching is theoretically analyzed and experimentally verified using the prototype circuit.
  • Asmarashid bin Ponniran, Koji Orikawa, Jun-ichi Itoh
    2015 IEEE 2ND INTERNATIONAL FUTURE ENERGY ELECTRONICS CONFERENCE (IFEEC) 2015年 [査読有り][通常論文]
     
    This paper proposes an interleaved high boost ratio three-stage Marx topology DC-DC boost converter (MTBC). In the proposed circuit, the parallel connection is applied at the input side in order to reduce the conduction loss and the copper loss. Meanwhile the multi-stage connection is applied at the output side in order to reduce the voltage rating of switching devices. In addition, with the interleaved switching scheme, the maximum current stress at a bottom switching device of the stage-I is reduced and the equivalent frequency at the output side becomes twice of the switching frequency. As a result, the inductance of the output inductor is reduced compared to that of a synchronized switching scheme. In addition, with the interleaved switching scheme, the output inductor volume is also reduced. Two prototypes of the three-stage MTBC are experimentally verified in order to confirm the converter design and the operation. Besides, the achieved maximum efficiency of the three-stage MTBC prototype with the synchronized switching scheme is 94.5% at the output power of 500 W.
  • Shunsuke Takuma, Koji Orikawa, Jun-ichi Itoh, Ryo Oshima, Hiroki Takahashi
    2015 IEEE ENERGY CONVERSION CONGRESS AND EXPOSITION (ECCE) 4678 - 4684 2015年 [査読有り][通常論文]
     
    This paper proposes a Zero Voltage Switching (ZVS) method for an isolated DC to three-phase AC converter using an indirect matrix converter at the secondary side of the transformer. Phase-shift control is applied to the inverter at the primary side of the transformer, while Pulse Density Modulation (PDM) is employed to the indirect matrix converter at the secondary side. The inverter at the secondary side achieves ZVS by synchronizing the gate pulses with the zero voltage period of the input voltage. As a result, the proposed method reduces switching losses of both two converters. The validity of the proposed method is confirmed by experiment with a 3-kW prototype. From the experimental results, the snubber loss generated by the leakage inductance which satisfies the conditions for ZVS is small and almost constant against the output power. It is concluded that the efficiency of the entire range of load with proposed control is improved by 2% in comparison to the isolated DC-AC converter using matrix converter. In addition, the loss of the inverter at primary side is reduced by 64.5% at rated output.
  • Sagehashi Ayato, Kusaka Keisuke, Orikawa Koji, Itoh Jun-ichi
    Power Electronics and ECCE Asia (ICPE-ECCE Asia), 2015 9th International Conference on 1017  2015年 [査読有り][通常論文]
  • Yoshiya Ohnuma, Koji Orikawa, Jun-ichi Itoh
    IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS 51 1 531 - 538 2015年01月 [査読有り][通常論文]
     
    This paper proposes a new circuit configuration and a control scheme for a single-phase current-source inverter with a power decoupling circuit which is called as the active buffer. The proposed inverter achieves a low-dc-input voltage ripple and also provides a sinusoidal current that can achieve unity power factor, without large passive components in the dc bus such as smoothing inductors and electrolytic capacitors. These components are conventionally required in order to decouple the power pulsation caused by the single-phase power source. In this paper, the fundamental operations of the proposed inverter are demonstrated experimentally. From the experimental results, the input voltage ripple is 8.87%, and the output current total harmonic distortion is 4.24%. In addition, an output power factor of 99% and a maximum efficiency of 94.9% are obtained. Finally, it is confirmed that the maximum power densities of the conventional circuit and the proposed circuit are 2.75 kW/L at the switching frequency of 70 kHz and 4.86 kW/L at the switching frequency of 80 kHz, respectively.
  • A. B. Ponniran, Koichi Matsuura, Koji Orikawa, Jun-ichi Itoh
    IEEJ Journal of Industry Applications 3 6 446 - 454 IEEJ 2014年06月01日 [査読有り][通常論文]
  • Jun-ichi Itoh, Tsuyoshi Nagano, Kenta Tanaka, Koji Orikawa, Noboru Yamada
    2014 IEEE ENERGY CONVERSION CONGRESS AND EXPOSITION (ECCE) 4568 - 4575 2014年 [査読有り][通常論文]
     
    This paper introduces performance of a power leveling system with a 3.0-MJ, 2900-r/min of flywheel energy storage for multiple parallel operations. In terms of cost reduction and improvement efficiency, this system uses low cost ball bearings at the low speed. Moreover, the system is composed by not a large capacity flywheel but many flywheels with small energy capacity but the cost reduction of the flywheel system. As a result, the cost reduction can be achieved by mass production. The proposed flywheel system is designed by a low-loss design method that focuses on the mechanical loss aspect. From the experimental results, it is confirmed that the charge and discharge efficiency of the mechanical part of the proposed flywheel system is 95.2% (charge 97.9%, discharge 97.5%). In addition, the suitable drive system with permanent magnet synchronous motors (PMSMs) are developed for the multiple parallel flywheels system. The PMSMs which consist of a main winding and a damping winding are driven by a single main inverter and small auxiliary inverters. From the experimental results, the validity of the parallel drives control method using two PMSMs is confirmed.
  • Jun-ichi Itoh, Kenji Noguchi, Koji Orikawa
    2014 INTERNATIONAL POWER ELECTRONICS CONFERENCE (IPEC-HIROSHIMA 2014 - ECCE-ASIA) 2277 - 2284 2014年 [査読有り][通常論文]
     
    This paper discusses an electric assisted bicycle which uses electric double layer capacitors (EDLCs) as a power source. EDLCs are charged through a rapid charger by using wireless power transmission. In this paper, first, the energy capacity of EDLCs is designed. Next, the antenna for the wireless power transmission and the charger are investigated. Third, this paper compares the volume and the power loss of the three kinds of DC-DC converters which are step-down type, boost-type and buck-boost type for the charging and discharging of EDLCs. As a result, boost-type is the most compact in the power capacity of the electric assisted bicycle. Finally, the proposed system is experimentally verified as a prototype. As a result, the proposed system can shorten to 1/4 the charging time of the conventional system.
  • Ayato Sagehashi, Keisuke Kusaka, Koji Orikawa, Jun-Ichi Itoh, Akio Momma
    2014 16TH INTERNATIONAL POWER ELECTRONICS AND MOTION CONTROL CONFERENCE AND EXPOSITION (PEMC) 569 - 574 2014年 [査読有り][通常論文]
     
    This paper investigates differences of parasitic inductances caused by DC bus bar patterns on printed circuit boards(PCB). The DC bus bar pattern on the PCB is limited depending on the layout of main circuits and the control circuits. Two patterns which are a laminated wiring pattern and a plane wiring pattern are compared in experiments and simulations. In this paper, it will be clarified that effects of the DC bus bars on PCBs such as a surge voltage of a switch in terms of the parasitic inductance depending on the circuits on PCBs. As a result, if the same parasitic inductance which is 20 nH, is realized between each wiring pattern at the same length, the plane wiring pattern requires over ten times of the pattern width compared with that of the laminated wiring pattern. Hence, the circuit size can be downsized when the laminated pattern is used. From the experimental results, the maximum surge voltage in the plane wiring pattern is larger than that in the laminated wiring pattern. In this case, the parasitic inductance value of the plane wiring pattern is three times that of the laminated wiring pattern. However, the surge voltage in the laminated pattern is reduced by 7% compared with the plane wiring pattern. As a consequence, the ratio of the surge voltage does not match that of the parasitic inductance. As a result, not only the parasitic inductance of the DC bus bar but also it is necessary to consider other parasitic inductances on PCBs such as parasitic inductances into input capacitors and the path between an upper MOSFET and a lower one and so on.
  • Koji Orikawa, Jun-ichi Itoh
    2014 INTERNATIONAL ELECTRONICS AND APPLICATION CONFERENCE AND EXPOSITION (PEAC) 1056 - 1061 2014年 [査読有り][通常論文]
     
    This paper discusses a high-efficiency power supply developed for implementation under low-voltage and high-current conditions for sintering applications such as the Spark Plasma Sintering (SPS) and so on. The proposed system consists of four 2,500-A units of the power supply connected in parallel. The output voltage of the proposed system is very low because load resistance is usually very small in SPS applications. Therefore, on the output side, many circuit components are connected in parallel. Especially, in the prototype circuit, many schottky barrier diodes are connected in parallel. As a result, equivalent parasitic capacitance of them could not be ignored from the view point of surge voltage. First, the circuit configuration and the control principle for the proposed low-voltage, high-current power supply are described. Second, the influence of the parasitic capacitance of them and parasitic inductances of each snubber component are clarified by theoretical discussion and simulations. Next, the prototype circuit demonstrates that each individual circuit yields a balanced output. Moreover, temperature of each component is measured during long time operation of the prototype circuit. Finally, it is clarified that experimental results of the surge voltage on the schottky barrier diode are correspond to the theoretical discussion by experiments.
  • Keisuke Kusaka, Koji Orikawa, Jun-ichi Itoh, Kazunori Morita, Kuniaki Hirao
    2014 INTERNATIONAL POWER ELECTRONICS CONFERENCE (IPEC-HIROSHIMA 2014 - ECCE-ASIA) 191 - 198 2014年 [査読有り][通常論文]
     
    In this paper, a multiple wireless power transfer system for multiple gate driver supplies of a medium voltage inverter is developed. The proposed isolation system achieves a galvanic isolation with an air-gap of 50 mm using a wireless power transfer with magnetic resonance coupling. It easily respects the standard of galvanic isolation, which is established by International electrotechnical commission (IEC). Moreover, the power is supplied from one transmitting board to six gate drivers without a solid magnetic core. In this paper, the isolation system is developed and tested. It is clarified that the isolation system transmits power of not less than 300 mW to each gate drivers beyond an air-gap. However, sum of the output power of the each receiving board are limited up to approximately 3.5 W because of a voltage drop in the equivalent series resistances of the transmission coils.
  • Yuki Nakata, Koji Orikawa, Jun-ichi Itoh
    2014 IEEE ENERGY CONVERSION CONGRESS AND EXPOSITION (ECCE) 571 - 578 2014年 [査読有り][通常論文]
     
    This paper discusses the pulse density modulation (PDM) control methods for a single-phase to three-phase matrix converter (MC) in the high-frequency application. This converter outputs a commercial power grid frequency, i. e. 50 Hz or 60 Hz from the input of several-hundred-kHz frequency. The proposed circuit achieves zero voltage switching operation by using the PDM control method. In this paper, two PDM control strategies are compared between a conventional PDM control method based on space vector modulation (SVM) and the proposed PDM control method, which is combined with SVM and a delta-sigma conversion. Also, the experimental results of the proposed control method will be demonstrated and discussed. As a result, the total harmonic distortion (THD) of the output voltage with the proposed PDM control method is improved to 1.87% from 9.05% of the conventional PDM control method.
  • Koji Orikawa, Yusuke Fujita, Jun-ichi Itoh
    2014 TWENTY-NINTH ANNUAL IEEE APPLIED POWER ELECTRONICS CONFERENCE AND EXPOSITION (APEC) 1329 - 1335 2014年 [査読有り][通常論文]
     
    This paper discusses a development for high output of 2.5 MHz inverter without fast-switching semiconductor switches. This inverter consists of a multi-phase inverter using conventional silicon semiconductor switches and multiple core transformers. In this paper, a principle of drop in inverter output voltage which reduces the inverter output voltage due to a relationship between dead-time and a leakage inductance of a transformer is clarified. In addition, two methods which are bifilar wound transformers and a LC series resonance are applied to the proposed circuit in order to achieve higher output power. The validity of two methods for higher output power is confirmed by experiments. Finally, the proposed circuit is applied to a wireless power transfer when a lamb bulb is used as a load.
  • Jun-ichi Itoh, Kenji Noguchi, Koji Orikawa
    IECON 2014 - 40TH ANNUAL CONFERENCE OF THE IEEE INDUSTRIAL ELECTRONICS SOCIETY 1453 - 1459 2014年 [査読有り][通常論文]
     
    This paper discusses an vehicle application which uses electric double layer capacitors (EDLCs) as a power source. EDLCs are charged through a rapid charger by using wireless power transmission. In this paper, as vehicle application, the electric assisted bicycle is considered. First, the antenna for the wireless power transmission and the charger are introduced. Next, this paper compares the volume and the power loss of the three kinds of DC-DC converters which are a buck-type, a boost-type and a buck-boost type for the charging and discharging of EDLCs. As a result, such as an electric assisted bicycle for small-capacity system, the boost-type is small. On the other hand, such as electric vehicles for large-capacity system, the buck-type is small. Finally, the proposed system is experimentally verified as a prototype. As a result, the proposed system can shorten to 1/4 the charging time of the conventional system.
  • Le Hoai Nam, Koji Orikawa, Jun-ichi Itoh
    2014 INTERNATIONAL POWER ELECTRONICS CONFERENCE (IPEC-HIROSHIMA 2014 - ECCE-ASIA) 3659 - 3666 2014年 [査読有り][通常論文]
     
    This paper proposes current control method for DCM to achieve same control performance as CCM. The proposed control loop is designed based on the conventional current control loop in CCM. By using only one PI controller and introduction of two correction factors, the proposed control method can control both CCM and DCM current exactly to design values. In this paper, the operation of the proposed control method is confirmed by simulation and experiment. The simulation results of the current response in both CCM and DCM agree with design values. In the experimental results, due to the delay in feedback, error 11.3% in rise time and error 2.5 point in overshoot occur. Furthermore, the voltage regulation experiment with the proposed current controller as a inner control loop is conducted. As load varies, the recovery time for the output voltage regulation is about 20 ms and the overshoot undershoot voltage is below 3%.
  • Toshiki Nakanishi, Koji Orikawa, Jun-ichi Itoh
    2014 INTERNATIONAL CONFERENCE ON RENEWABLE ENERGY RESEARCH AND APPLICATION (ICRERA) 653 - 658 2014年 [査読有り][通常論文]
     
    This paper discusses a AC-DC converter which is constructed by a Modular Multilevel Converter (MMC) for a wind power generation system connected to Micro-grid. The proposed system which is constructed the MMC with an H-bridge cell achieves to convert from a generator voltage of 3.3 kV into DC bus voltage of 340 V. Moreover, as a fundamental evaluation, the experimental result by miniature model of 700 W confirms that the proposed system achieves the step-down operation from input voltage of 200 V into DC voltage of 65 V. Finally, the proposed system maintains the capacitor voltage of each cell to the voltage command. Furthermore, the maximum voltage error between the voltage command of the cell capacitor and the measured voltage is 10% or less.
  • Lun-ichi Itoh, Takahiro Araki, Koji Orikawa
    2014 INTERNATIONAL POWER ELECTRONICS CONFERENCE (IPEC-HIROSHIMA 2014 - ECCE-ASIA) 1912 - 1919 2014年 [査読有り][通常論文]
     
    This paper discusses a volume of an EMC filter and a cooling system that are used for a PWM inverter with wide band-gap devices. At first, the volume of reactor that is used for EMC filter such as common mode coke coils and differential mode choke coils are estimated by theoretically. Then, the relationship between the carrier frequency of the PWM inverter and the total volume of filter reactors are clarified by simulation. Moreover, the relationship between the carrier frequency and the volume of a cooling system is calculated based on experimental results. As a result, the total volume of the inverter system that contains filter reactors and cooling system will be reduced by 54% at the carrier frequency of 300 kHz by using a two stage filter compared to case of the carrier frequency of 150 kHz by using one stage filter. In addition, an induction motor is driven by a prototype of GaN-FET inverter system with a 300-kHz carrier frequency. As a result, the conduction noise is suppressed below the limit of CISPR. Therefore, the proposed design method for EMC filters is valid in the experiment. Furthermore, the power loss of EMC filter is less than 2% compared with the total loss of the GaN-FET inverter system.
  • 折川幸司, 高橋広樹, 五十嵐寿勝, 伊東淳一
    電気学会論文誌 D 134 1 82 - 89 2014年 [査読無し][通常論文]
     
    A problem with an energy storage system with a flywheel is the larger power consumption during standby as compared with that of a battery or an EDLC. In order to reduce power consumption, a direct transmission mode of a matrix converter, in which the power grid is directly connected to an induction motor, is applied. However, a rush output current will occur in the matrix converter when the mode of the matrix converter is changed from the PWM mode to the direct transmission mode. In order to solve this problem, in this paper, a transition control using an AC chopper mode is proposed. In addition, the validity of the proposed control is experimentally demonstrated. Finally, the power loss of the matrix converter is analyzed for both a vector control and the direct transmission mode. © 2014 The Institute of Electrical Engineers of Japan.
  • Yoshiya Ohnuma, Koji Orikawa, Jun-Ichi Itoh
    2013 IEEE Energy Conversion Congress and Exposition, ECCE 2013 3094 - 3101 2013年 [査読有り][通常論文]
     
    This paper proposes a new circuit configuration and a control scheme for a single-phase current source inverter with a power decoupling circuit which is called as the active buffer. The proposed inverter achieves low-DC-input voltage ripple and also provides sinusoidal current that can achieve unity power factor, without large passive components in DC bus such as smoothing inductors and electrolytic capacitors, which are conventionally required in order to decouple the power pulsation caused by single-phase power source. In this paper, the fundamental operations of the proposed inverter are demonstrated experimentally. From the experimental results, the input voltage ripple is 8.87% and the output current THD is 4.24%. In addition, the output power factor over of 99% and a maximum efficiency of 94.9% are obtained. Finally, it is confirmed that the maximum power density of the conventional circuit and the proposed circuit are 2.75 kW/L at the switching frequency 70 kHz and 4.86 kW/L at the switching frequency 80 kHz, respectively. © 2013 IEEE.
  • Yuki Nakata, Yoshiya Ohnuma, Koji Orikawa, Goh Teck Chiang, Jun-Ichi Itoh
    Proceedings of the International Conference on Power Electronics and Drive Systems 1003 - 1008 2013年 [査読有り][通常論文]
     
    This paper proposes a single phase to single phase power conversion that is based on the indirect type of matrix converter, an active buffer circuit and boost chopper circuit. Pulse density modulation (PDM) control which can achieve zero voltage switching, is applied to the inverter part. From the simulation results, the operation to compensate the power ripple is confirmed because the DC link current is controlled approximately 0.5 A constantly. However, there is the 35% of the current ripple because of the quantization error when PDM control is applied to the inverter. As a result, the THD of the output voltage and input current are 4.9% and 42.7% respectively. As a result, a validity of the proposed circuit is confirmed. © 2013 IEEE.
  • Goh Teck Chiang, Koji Orikawa, Yoshiya Ohnuma, Jun-ichi Itoh
    39TH ANNUAL CONFERENCE OF THE IEEE INDUSTRIAL ELECTRONICS SOCIETY (IECON 2013) 4862 - 4867 2013年 [査読有り][通常論文]
     
    This paper discusses and evaluates the performance of a 50-kVA three-phase AC to DC matrix converter. Comparing to the conventional converter, which consists of a PWM rectifier and an inverter, the matrix converter does not require a large reactor at the three-phase input side, and require no DC smoothing capacitor at the DC link part. A space vector modulation based on the virtual AC-DC-AC conversion with four-step commutation patterns is proposed for the converter. From the experimental results, the converter can obtain 2.49% THD on the input current and achieves approximately 91.4% efficiency at 40kW.
  • Masakazu Kato, Koji Orikawa, Jun-ichi Itoh, Noboru Saitoh
    2013 1ST INTERNATIONAL FUTURE ENERGY ELECTRONICS CONFERENCE (IFEEC 2013) 211 - 216 2013年 [査読有り][通常論文]
     
    This paper proposes a fast accelerating method for the weaving machine drive system, which an open winding of the induction motor is used and connected in series to an inverter and a switching unit. Generally, the star(Y)-delta(Delta) switching method is used in the start-up mode in order to suppress the rush current in general applications. However, in weaving machine, the rush current is required in the start-up mode in order to increase starting torque. If the starting torque is not enough to the induction motor, deficiencies of fabric cloth which is called "start-up marks" will happen[1]. We proposes the Delta-switching method that achieve high rush current in order to increase starting torque for weaving machine drive system. From the experimental results, the start-up time of the proposed system is kept to the same as the direct power grid connection. In addition, rush current of the proposed system is decreased to 37.7% comparing to the direct power grid connection.
  • 折川幸司, 伊東淳一
    電気学会論文誌 D 133 3 350 - 359 2013年 [査読無し][通常論文]
     
    This paper clarifies the principle of the surge voltage of a rectifier diode that is connected to a transformer in an isolated power converter. It is confirmed that the theoretical vibrational frequency of the diode voltage in the equivalent circuit is in agreement with the experimental result. In addition, the design method of the RC snubber circuit is discussed by using the equivalent circuit consisting of a transformer, a snubber circuit, and a diode. Finally, the validity of the design method is confirmed by the experimental results. © 2013 The Institute of Electrical Engineers of Japan.
  • K. Orikawa, J. Itoh
    IEEJ Journal of Industry Applications 1 3 164 - 171 電気学会 2012年11月01日 [査読有り][通常論文]
  • Koji Orikawa, Jun-ichi Itoh
    INTERNATIONAL CONFERENCE ON RENEWABLE ENERGY RESEARCH AND APPLICATIONS (ICRERA) 2012年 [査読有り][通常論文]
     
    This paper clarifies the principle of the surge voltage in the diode rectifier that is connected to the transformer in the isolated DC-DC converter. In addition, the design method of the RC snubber circuit is discussed by using the equivalent circuit that is consisting of the transformer, the snubber circuit and the diode. Finally, the experimental results are provided to validate the design method.
  • Koji Orikawa, Jun-ichi Itoh
    2012 15TH INTERNATIONAL POWER ELECTRONICS AND MOTION CONTROL CONFERENCE (EPE/PEMC) 2012年 [査読有り][通常論文]
     
    This paper discusses a high-efficiency AC-DC converter developed for low-voltage and high-current conditions for sintering power applications. First, the circuit configuration and the control principle for the proposed low-voltage high-current AC-DC converter are described. The proposed system consists of four 2,500-A units of the AC-DC converter connected in parallel. The input current harmonics are suppressed by multiple transformers on the input side. Also, imbalance issues on the transformer parameters and the output wiring are discussed. The proposed system demonstrates that each individual circuit yields a balanced 10,000-A(10-kA) output. In addition, loss analysis shows that the power loss on the secondary rectifier is 49% dominated by semiconductor loss. Furthermore, it is shown that by implementing a MOSFET synchronous rectifier instead of a Schottky barrier diode, the loss will be reduced by 35%. Finally, the input current harmonics are reduced by using multiple transformers and the validity of this result is demonstrated.
  • Jun-Ichi Itoh, Koichi Matsuura, Koji Orikawa
    8th International Conference on Power Electronics - ECCE Asia: "Green World with Power Electronics", ICPE 2011-ECCE Asia 1315 - 1322 2011年 [査読有り][通常論文]
     
    The loss analysis of a switched capacitor converter (SCC) with a boost reactor is discussed in this paper. The proposed SCC can deliver an output voltage independent from the circuit structure comparing to other voltage control methods. The main feature of this circuit is that most of the energy for the boost up function is transferred from a flying capacitor which results the inductance of the input reactor can be reduced. The reactor size of the proposed SCC is smaller than that of the conventional boost converters. A 1000 W 3-level SCC prototype has been built and tested. The efficiency of 97.8% is achieved at 1000 W when the boost up ratio is three times. Moreover, the loss analysis shows the main loss of the proposed SCC is the diode conduction loss. © 2011 IEEE.
  • Jun-Ichi Itoh, Koji Orikawa
    2010 IEEE Energy Conversion Congress and Exposition, ECCE 2010 - Proceedings 1414 - 1421 2010年 [査読有り][通常論文]
     
    This paper describes the comparison of two proposed circuits in terms of the efficiency. Series-parallel compensation type DC-DC converters have been proposed for hybrid power supplies using both fuel cell and battery. The output voltage is controlled by a series converter that regulates only the differential voltage between the fuel cell voltage and the output voltage. Although the load condition is changed, the variation of the fuel cell current is suppressed by a battery through operation of the parallel converter. The experimental results confirmed that the proposed circuit could achieve maximum efficiency point of 98.8% and 99.1% in the small differential voltage region, respectively. In addition, the loss distribution of the each proposed circuit is clarified by the loss analysis. As a result, it is confirmed that the optimizing of the reactor is required in order to improve the efficiency of the proposed circuit. © 2010 IEEE.
  • Koji Orikawa, Jun-ichi Itoh
    EPE: 2009 13TH EUROPEAN CONFERENCE ON POWER ELECTRONICS AND APPLICATIONS, VOLS 1-9 1813 - 1821 2009年 [査読有り][通常論文]
     
    This paper proposes a novel DC-DC converter for a hybrid power supply using both a fuel cell and a battery. In the proposed circuit, the power converter with the battery is connected in series to the fuel cell. The output voltage is controlled by a series converter that regulates only the differential voltage between the fuel cell voltage and the output voltage. The power rating of conventional buck-boost DC-DC converters are dominated by the input voltage or the output voltage. In contrast, since the voltage rating of the proposed circuit requires the differential voltage between the fuel cell voltage and the output voltage, the power rating of the proposed circuit is smaller than that of the conventional converters. In addition, in order to suppress large current ripple in the fuel cell, a parallel converter is added to the series converter. The experimental results confirmed that the proposed circuit could achieve 98.8% at the maximum efficiency point in the small differential voltage region.
  • Koji Orikawa, Jun-ichi Itoh
    INTELEC 09 - 31ST INTERNATIONAL TELECOMMUNICATIONS ENERGY CONFERENCE 109 - 114 2009年 [査読有り][通常論文]
     
    This paper proposes a novel DC-DC converter for hybrid power supplies using both fuel cell and battery. The output voltage is controlled by a series converter that regulates only the differential voltage between the fuel cell voltage and the output voltage. Although the load condition is changed, the variation of the fuel cell current is suppressed by a battery through operation of the parallel converter. The experimental results confirmed that the proposed circuit could achieve maximum efficiency point of 98.8% in the small differential voltage region. In addition, the loss analysis clarified the relations among the ripple current of the inductors, the inductor voltage and the inductors losses. As a result, it is confirmed that the proposed circuit achieves the minimum loss of the copper loss and the iron loss in the inductors when the differential voltage is small.
  • Sakuraba Tomokazu, Kusaka Keisuke, Orikawa Koji, Itoh Jun-ichi
    電子デバイス 半導体電力変換合同研究会 [査読無し][通常論文]

書籍

  • パワーコンバータに用いられる高周波トランスの最新技術動向
    折川幸司 
    電気総合誌「OHM」 2019年10月

その他活動・業績

特許

  • 堀口 敏夫, 伊東 淳一, 折川 幸司  オリンパス株式会社, 国立大学法人長岡技術科学大学  201303096472568480
  • 堀口 敏夫, 伊東 淳一, 折川 幸司  オリンパス株式会社, 国立大学法人長岡技術科学大学  201303003529108599
  • 堀口 敏夫, 伊東 淳一, 折川 幸司  オリンパス株式会社, 国立大学法人長岡技術科学大学  201003045562998063
  • 堀口 敏夫, 伊東 淳一, 折川 幸司  オリンパス株式会社, 国立大学法人長岡技術科学大学  200903051632429931

受賞

  • 2018年08月 平成30年電気学会産業応用部門活動功労賞
     
    受賞者: 折川幸司
  • 2018年03月 パワーアカデミー萌芽研究優秀賞
     
    受賞者: 折川幸司
  • 2016年08月 平成28年電気学会産業応用部門論文賞
     
    受賞者: 折川幸司
  • 2016年01月 平成27年電気学会産業応用部門研究会 優秀論文発表賞
     
    受賞者: 折川幸司
  • 2013年11月 IECON2013 Best paper in session
     
    受賞者: 折川幸司
  • 2010年04月 平成21年度電気関係学会関西支部連合大会奨励賞
     
    受賞者: 折川幸司
  • 2010年03月 2009年電気学会産業応用部門 優秀論文発表賞
     
    受賞者: 折川幸司

共同研究・競争的資金等の研究課題

  • 高電力密度を実現するMHz級低背トランスの限界設計理論の体系化
    日本学術振興会:科学研究費助成事業 若手研究
    研究期間 : 2020年04月 -2023年03月 
    代表者 : 折川 幸司
  • 13.56MHz出力スイッチング高周波電源を実現する周波数逓倍技術に関する研究
    研究期間 : 2017年04月 -2020年03月 
    代表者 : 折川幸司
  • 周波数逓倍を利用した超高周波出力を可能とする高周波電源の開発
    パワーアカデミー:萌芽研究
    代表者 : 折川幸司
  • 超高周波を出力する周波数逓倍回路に基づく高周波電源の基礎検証
    公益財団法人東電記念財団:一般研究
    代表者 : 折川幸司

大学運営

委員歴

  • 2018年06月 - 現在   半導体電力変換技術委員会   1号委員
  • 2018年04月 - 現在   電気学会SNS運営WG
  • 2017年06月 - 現在   電気学会北海道⽀部役員会
  • 2014年06月 - 現在   電気学会 論文委員会(D1グループ) 委員
  • 2019年04月 - 2019年12月   令和元年度電気・情報関係学会北海道支部連合大会実行委員
  • 2018年06月 - 2019年06月   平成31年電気学会全国大会実行委員会
  • 2017年07月 - 2019年06月   電気学会 パワーコンバータに用いられる受動部品の研究・開発および製作技術協同研究委員会
  • 2016年12月 - 2019年03月   IPEC2018論⽂委員会
  • 2018年04月 - 2018年12月   平成30年度 産業応用部門大会論文委員会
  • 2017年09月 - 2018年09月   平成30年電子・情報・システム部門大会実行委員会
  • 2017年02月 - 2017年12月   平成29年度 産業応⽤部⾨⼤会論⽂委員会
  • 2016年08月 - 2017年12月   平成29年度 産業応⽤部⾨⼤会実⾏委員会


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