In this study, we developed a four-wheel-driven autonomous mobile robot to transport heavy objects on narrow alleys and steep slopes. The robot, which weighs 450 kg, is driven by four 650 W hub motors to climb 20° steep slopes and travel through a narrow alley. Two 2D-LiDARs attached to the front and rear of the robot body are used for highly accurate driving. A method based on the least squares approach for estimating the position and posture of the robot body is proposed by using the point cloud information of the side wall of the narrow alley. Field experiments on test courses demonstrated that the autonomous robot could transport heavy objects over steep slopes and travel in a narrow alley with high accuracy.
{"title":"Development of an Autonomous Mobile Robot to Transport Heavy Objects on Narrow Alleys and Steep Slopes","authors":"Yuichiro Kanazawa, Peirang Li, Chi Zhu","doi":"10.1002/eej.23482","DOIUrl":"https://doi.org/10.1002/eej.23482","url":null,"abstract":"<div>\u0000 \u0000 <p>In this study, we developed a four-wheel-driven autonomous mobile robot to transport heavy objects on narrow alleys and steep slopes. The robot, which weighs 450 kg, is driven by four 650 W hub motors to climb 20° steep slopes and travel through a narrow alley. Two 2D-LiDARs attached to the front and rear of the robot body are used for highly accurate driving. A method based on the least squares approach for estimating the position and posture of the robot body is proposed by using the point cloud information of the side wall of the narrow alley. Field experiments on test courses demonstrated that the autonomous robot could transport heavy objects over steep slopes and travel in a narrow alley with high accuracy.</p>\u0000 </div>","PeriodicalId":50550,"journal":{"name":"Electrical Engineering in Japan","volume":"217 4","pages":""},"PeriodicalIF":0.4,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142868671","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study presents the development of a small electric vehicle (EV) traction drive motor using Fe-based amorphous laminated cores that can be mass produced. The following innovative technologies are developed to realize the amorphous laminated core: (1) production technology for thicker amorphous alloy foils to reduce the number of machining operations and (2) punching press technology for amorphous alloy foils that improves the usability of the tool life and maintains quality. The interior permanent magnet synchronous motor (IPMSM) using the amorphous laminated core is designed to be compatible with a 4.5-kW-class small EV traction drive with high efficiency while satisfying the required torque characteristics. A prototype of the designed IPMSM was manufactured and evaluated. The test machine achieves a maximum efficiency of 98.7% and a wide range of efficiencies exceeding 97%. Additionally, the prototype motor exhibit improved efficiency in all operating points compared with a prototype manufactured using an electrical steel sheet.
{"title":"Traction Drive Motor for Small EVs Using Mass Producible Amorphous Laminated Cores","authors":"Yoshiaki Kano, Hirokazu Kanekiyo, Yohei Suzuki","doi":"10.1002/eej.23484","DOIUrl":"https://doi.org/10.1002/eej.23484","url":null,"abstract":"<div>\u0000 \u0000 <p>This study presents the development of a small electric vehicle (EV) traction drive motor using Fe-based amorphous laminated cores that can be mass produced. The following innovative technologies are developed to realize the amorphous laminated core: (1) production technology for thicker amorphous alloy foils to reduce the number of machining operations and (2) punching press technology for amorphous alloy foils that improves the usability of the tool life and maintains quality. The interior permanent magnet synchronous motor (IPMSM) using the amorphous laminated core is designed to be compatible with a 4.5-kW-class small EV traction drive with high efficiency while satisfying the required torque characteristics. A prototype of the designed IPMSM was manufactured and evaluated. The test machine achieves a maximum efficiency of 98.7% and a wide range of efficiencies exceeding 97%. Additionally, the prototype motor exhibit improved efficiency in all operating points compared with a prototype manufactured using an electrical steel sheet.</p>\u0000 </div>","PeriodicalId":50550,"journal":{"name":"Electrical Engineering in Japan","volume":"217 4","pages":""},"PeriodicalIF":0.4,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142868433","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hiroki Yamanaka, Mayu Yamaguchi, Ippei Matsuura, Hirotaka Shimizu
Reverse power flow from a photovoltaic (PV) power generation system to distribution system is limited below a certain limit value. The behavior of a power conditioning system (PCS) for large capacity PV power generation system when the output power approached the output power limit value was experimentally estimated. Under the condition, the PCS became uncontrollable. It was pointed out that this phenomenon was caused by the maximum power point tracking (MPPT) control of the PCS. Furthermore, some methods to avoid the uncontrollable condition of PCS were shown.
{"title":"An Experimental Study on Behavior of Power Conditioning System for Photovoltaic Power Generation System Connected to End of Distribution Line","authors":"Hiroki Yamanaka, Mayu Yamaguchi, Ippei Matsuura, Hirotaka Shimizu","doi":"10.1002/eej.23481","DOIUrl":"https://doi.org/10.1002/eej.23481","url":null,"abstract":"<div>\u0000 \u0000 <p>Reverse power flow from a photovoltaic (PV) power generation system to distribution system is limited below a certain limit value. The behavior of a power conditioning system (PCS) for large capacity PV power generation system when the output power approached the output power limit value was experimentally estimated. Under the condition, the PCS became uncontrollable. It was pointed out that this phenomenon was caused by the maximum power point tracking (MPPT) control of the PCS. Furthermore, some methods to avoid the uncontrollable condition of PCS were shown.</p>\u0000 </div>","PeriodicalId":50550,"journal":{"name":"Electrical Engineering in Japan","volume":"217 4","pages":""},"PeriodicalIF":0.4,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142868013","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Despite ensuring the integrity of bogie frames for railway vehicles via nondestructive inspections during periodic maintenance, the possibility of fatigue cracks occurring at locations other than the predetermined inspection points cannot be dismissed. Therefore, fatigue cracks can be prevented more efficiently by assessing the overall degree of fatigue damage to the entire bogie frame and determining the results via nondestructive inspections. In this study, dynamic stresses in the bogie frame during running were estimated via finite element dynamic analysis by using the axle box acceleration as input, and the degree of fatigue damage and life were calculated from the waveform of the estimated stresses. Furthermore, we developed a bogie frame fatigue prediction system based on a high-speed and high-precision stress calculation method. The developed system visualized the overall relative life.
{"title":"Development of fatigue prediction system for bogie frame using a dynamic analysis model based on high-speed and high-precision stress estimation method","authors":"Yosuke Yamazaki, Takahiro Fujimoto, Yoshiyuki Shimokawa, Hideki Minami, Osamu Kondo, Gaku Iokibe, Junichi Nakagawa","doi":"10.1002/eej.23469","DOIUrl":"10.1002/eej.23469","url":null,"abstract":"<p>Despite ensuring the integrity of bogie frames for railway vehicles via nondestructive inspections during periodic maintenance, the possibility of fatigue cracks occurring at locations other than the predetermined inspection points cannot be dismissed. Therefore, fatigue cracks can be prevented more efficiently by assessing the overall degree of fatigue damage to the entire bogie frame and determining the results via nondestructive inspections. In this study, dynamic stresses in the bogie frame during running were estimated via finite element dynamic analysis by using the axle box acceleration as input, and the degree of fatigue damage and life were calculated from the waveform of the estimated stresses. Furthermore, we developed a bogie frame fatigue prediction system based on a high-speed and high-precision stress calculation method. The developed system visualized the overall relative life.</p>","PeriodicalId":50550,"journal":{"name":"Electrical Engineering in Japan","volume":"217 3","pages":""},"PeriodicalIF":0.4,"publicationDate":"2024-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141507241","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The axial gap structure of a half-wave rectified variable field flux motor (AG-HVFM) has been proposed, which has a double stator structure and field winding short-circuited by a diode. Although the AG-HVFM can achieve a high-efficiency drive in wide speed and torque range via variable field flux control, its structure deteriorates the average torque and torque ripple. In this paper, we sequentially design the core shape, aspect ratio, and current control method for an AG-HVFM to improve its torque characteristics.
{"title":"Design and improvement of torque characteristics of half-wave rectified variable field flux motor with axial gap structure","authors":"Kentaro Yazama, Takashi Abe, Yoshitsugu Otomo, Takahiro Koga, Yuzen Shimohara","doi":"10.1002/eej.23480","DOIUrl":"https://doi.org/10.1002/eej.23480","url":null,"abstract":"<p>The axial gap structure of a half-wave rectified variable field flux motor (AG-HVFM) has been proposed, which has a double stator structure and field winding short-circuited by a diode. Although the AG-HVFM can achieve a high-efficiency drive in wide speed and torque range via variable field flux control, its structure deteriorates the average torque and torque ripple. In this paper, we sequentially design the core shape, aspect ratio, and current control method for an AG-HVFM to improve its torque characteristics.</p>","PeriodicalId":50550,"journal":{"name":"Electrical Engineering in Japan","volume":"217 3","pages":""},"PeriodicalIF":0.4,"publicationDate":"2024-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142152287","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Recent methods using thermistors as an early detection of skin cancer require the higher resolution of 5 mK. Previously, the authors developed a vacuum insulated temperature device that calibrates the resistance temperature characteristics of thermistors, so that it improves the temperature resolution and accuracy of skin cancer diagnosis. In this study, the operational methods of the calibration system were compared for improving further accuracy using the temperature calibration device and the oil tank calibration device. The results of the comparison indicated that the temperature calibration device is probably as accurate as the oil tank calibration device.
{"title":"Evaluation of a vacuum insulated temperature calibration device to calibrate thermistor characteristics for skin cancer diagnosis","authors":"Homei Fujita, Takashi Nonaka, Yasushi Hosokawa, Takuma Kogawa, Fuhui Guo, Yuya Iseki, Miyo Yokota, Takahiro Okabe, Shigenao Maruyama","doi":"10.1002/eej.23471","DOIUrl":"https://doi.org/10.1002/eej.23471","url":null,"abstract":"<p>Recent methods using thermistors as an early detection of skin cancer require the higher resolution of 5 mK. Previously, the authors developed a vacuum insulated temperature device that calibrates the resistance temperature characteristics of thermistors, so that it improves the temperature resolution and accuracy of skin cancer diagnosis. In this study, the operational methods of the calibration system were compared for improving further accuracy using the temperature calibration device and the oil tank calibration device. The results of the comparison indicated that the temperature calibration device is probably as accurate as the oil tank calibration device.</p>","PeriodicalId":50550,"journal":{"name":"Electrical Engineering in Japan","volume":"217 3","pages":""},"PeriodicalIF":0.4,"publicationDate":"2024-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142152271","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yuta Konno, Rion Takahashi, Faramarz Alsharif, Atsushi Umemura
In recent years, wind power generation has been promoted as a countermeasure to global environmental problems. However, the introduction of many wind power generators into the power system may cause system frequency fluctuations. This paper proposes a control method to reduce system frequency fluctuations by using the rotor kinetic energy (RKE) of a variable speed wind turbine (VSWT). When the frequency falls, this method suppresses fluctuations by consuming RKE to increase VSWT power generation, and when it rises, it decreases VSWT power generation by accumulating RKE. The effectiveness of this method is confirmed through simulations using PSCAD/EMTDC.
{"title":"Centralized control of large-scale wind farm for system frequency stabilization of the power system","authors":"Yuta Konno, Rion Takahashi, Faramarz Alsharif, Atsushi Umemura","doi":"10.1002/eej.23479","DOIUrl":"https://doi.org/10.1002/eej.23479","url":null,"abstract":"<p>In recent years, wind power generation has been promoted as a countermeasure to global environmental problems. However, the introduction of many wind power generators into the power system may cause system frequency fluctuations. This paper proposes a control method to reduce system frequency fluctuations by using the rotor kinetic energy (RKE) of a variable speed wind turbine (VSWT). When the frequency falls, this method suppresses fluctuations by consuming RKE to increase VSWT power generation, and when it rises, it decreases VSWT power generation by accumulating RKE. The effectiveness of this method is confirmed through simulations using PSCAD/EMTDC.</p>","PeriodicalId":50550,"journal":{"name":"Electrical Engineering in Japan","volume":"217 3","pages":""},"PeriodicalIF":0.4,"publicationDate":"2024-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142152214","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We investigated AC breakdown characteristics of ultra violet curable epoxy resin (UV-EP) with nitrogen fine bubbles (FBs) in order to improve insulating properties of UV-EP. As a result, it was found that self-made FB generator mainly add FBs with a diameter between 60 and 150 nm to FB-EP before curing. In addition, SEM images revealed that FB-EP has FBs after curing. Bubble diameter in FB-EP after curing was estimated between 55 and 140 nm due to resin shrinkage. Furthermore, partial discharge inception voltage and electric strength of FB-EP with FB addition for 10 min were almost the same as No FB-EP.
{"title":"AC breakdown characteristics of ultra violet curable epoxy resin with nitrogen fine bubbles","authors":"Nobutaka Araoka, Norimitsu Takamura, Tsubasa Inoue, Masahiro Hanai","doi":"10.1002/eej.23478","DOIUrl":"10.1002/eej.23478","url":null,"abstract":"<p>We investigated AC breakdown characteristics of ultra violet curable epoxy resin (UV-EP) with nitrogen fine bubbles (FBs) in order to improve insulating properties of UV-EP. As a result, it was found that self-made FB generator mainly add FBs with a diameter between 60 and 150 nm to FB-EP before curing. In addition, SEM images revealed that FB-EP has FBs after curing. Bubble diameter in FB-EP after curing was estimated between 55 and 140 nm due to resin shrinkage. Furthermore, partial discharge inception voltage and electric strength of FB-EP with FB addition for 10 min were almost the same as No FB-EP.</p>","PeriodicalId":50550,"journal":{"name":"Electrical Engineering in Japan","volume":"217 3","pages":""},"PeriodicalIF":0.4,"publicationDate":"2024-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141384064","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
As one of NEDO's international demonstration projects, a large-capacity hybrid battery storage system which consists of two types of battery cells with different charge-discharge characteristics was constructed in the state of Lower Saxony in the Federal Republic of Germany. By using the hybrid battery system has a lithium-ion which has an advantage in short time and high rate, and a sodium-sulfur battery (NAS) which has an advantage in long time and low rate, the tender participation in the balancing power market in Germany had been executed. The hybrid battery storage system could successfully drive and provided services for primary and secondary control reserves, elimination of power imbalance, and reactive power injection, as well as a combination of these services.
{"title":"Demonstration of participation in the German balancing power market using a large-capacity hybrid battery storage system","authors":"Keiichi Hirose, Hirohide Tanaka, Masayuki Dewaki, Kazutaka Hayashi, Yousuke Mikami, Yoshiki Hayashi, Hiroshi Arita, Saori Hamamura, Naoki Hirai","doi":"10.1002/eej.23466","DOIUrl":"10.1002/eej.23466","url":null,"abstract":"<p>As one of NEDO's international demonstration projects, a large-capacity hybrid battery storage system which consists of two types of battery cells with different charge-discharge characteristics was constructed in the state of Lower Saxony in the Federal Republic of Germany. By using the hybrid battery system has a lithium-ion which has an advantage in short time and high rate, and a sodium-sulfur battery (NAS) which has an advantage in long time and low rate, the tender participation in the balancing power market in Germany had been executed. The hybrid battery storage system could successfully drive and provided services for primary and secondary control reserves, elimination of power imbalance, and reactive power injection, as well as a combination of these services.</p>","PeriodicalId":50550,"journal":{"name":"Electrical Engineering in Japan","volume":"217 2","pages":""},"PeriodicalIF":0.4,"publicationDate":"2024-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141166968","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Masahiro Hori, Masanori Sawahata, Takafumi Hara, Minori Nagata
Electrification is progressing across different fields such as automobiles and construction machinery. Motors for electric systems are required to be compact and achieve high power density. In this study, we developed a small motor with rotation speed of 22,000 r/min by reducing stress concentration. Each pole has three magnets in the circumferential direction, and the magnets are arranged in a U-shape. The magnet insert slots are comprised of expanded flux barriers on the inner diameter side and a guide-less structure. The magnet slots reduce stress concentration. Additionally, the rotor has two dents on the outer diameter surface and expanded flux barriers on the outer diameter side. The dents have different shapes between the North (N) and South (S) poles. The structures reduce the torque ripple.
电气化正在汽车和建筑机械等不同领域取得进展。用于电动系统的电机要求结构紧凑、功率密度高。在这项研究中，我们通过减少应力集中，开发了一种转速为 22,000 r/min 的小型电机。每个磁极在圆周方向上有三块磁铁，磁铁呈 U 形排列。磁铁插入槽由内径一侧的膨胀磁通屏障和无导向结构组成。磁铁插槽可减少应力集中。此外，转子的外径表面有两个凹痕，外径一侧有膨胀磁通势垒。凹痕在北极（N）和南极（S）之间形状不同。这些结构减少了扭矩波纹。
{"title":"Development of low-torque-ripple motor with high rotational speed to downsize electrical systems","authors":"Masahiro Hori, Masanori Sawahata, Takafumi Hara, Minori Nagata","doi":"10.1002/eej.23470","DOIUrl":"10.1002/eej.23470","url":null,"abstract":"<p>Electrification is progressing across different fields such as automobiles and construction machinery. Motors for electric systems are required to be compact and achieve high power density. In this study, we developed a small motor with rotation speed of 22,000 r/min by reducing stress concentration. Each pole has three magnets in the circumferential direction, and the magnets are arranged in a U-shape. The magnet insert slots are comprised of expanded flux barriers on the inner diameter side and a guide-less structure. The magnet slots reduce stress concentration. Additionally, the rotor has two dents on the outer diameter surface and expanded flux barriers on the outer diameter side. The dents have different shapes between the North (N) and South (S) poles. The structures reduce the torque ripple.</p>","PeriodicalId":50550,"journal":{"name":"Electrical Engineering in Japan","volume":"217 2","pages":""},"PeriodicalIF":0.4,"publicationDate":"2024-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141148603","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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