A dielectric barrier discharge load (DBD) with a maintenance voltage of 1.5 kV has been successfully driven stably from a 48 V inverter only by resonance voltage boost and no transformer. The proposed circuit consists of a two-stage resonant circuit. The circuit operation is investigated using both prototyping measurement and circuit simulation, which shows that despite the high Q value, the design margin and operating stability of the circuit are extremely wide. It is found that this operational stability can be explained by considering the impedance characteristics of DBD. We believe that the circuit is suitable for driving discharge loads such as DBD in practical applications.
{"title":"Transformer-less drive and operation stability analysis of dielectric barrier discharge using a double resonance circuit","authors":"Taichiro Tamida, Ryota Nagata, Taiga Itani","doi":"10.1002/eej.23455","DOIUrl":"10.1002/eej.23455","url":null,"abstract":"<p>A dielectric barrier discharge load (DBD) with a maintenance voltage of 1.5 kV has been successfully driven stably from a 48 V inverter only by resonance voltage boost and no transformer. The proposed circuit consists of a two-stage resonant circuit. The circuit operation is investigated using both prototyping measurement and circuit simulation, which shows that despite the high Q value, the design margin and operating stability of the circuit are extremely wide. It is found that this operational stability can be explained by considering the impedance characteristics of DBD. We believe that the circuit is suitable for driving discharge loads such as DBD in practical applications.</p>","PeriodicalId":50550,"journal":{"name":"Electrical Engineering in Japan","volume":"217 1","pages":""},"PeriodicalIF":0.4,"publicationDate":"2023-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138537540","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}
A model expressing beams, pillars, and electrical wiring in a building for lightning surge simulation by circuit analysis method is proposed in this paper. The proposed model expresses the self-surge impedance of the electrical wiring as a function of the distance between conductors and the radius of the electrical wiring. The mutual impedance is expressed by the distance between the surfaces of a structure and a nearby wire instead of the distance between the conductor centers. In the case of two conductors having far different radii in proximity, the distribution of electromagnetic fields around the two conductors is similar in horizontal and vertical arrangements. Thus, the electrical wiring nearby pillars can be treated as a horizontal conductor. The circuit analysis results show that the voltage difference generated between the structure and the electrical wiring is calculated more precisely by the proposed model than by the conventional model.
{"title":"A circuit model of electrical wiring nearby building structure for lightning surge analysis","authors":"Hideyuki Dei, Yoki Ikeda, Naoto Nagaoka","doi":"10.1002/eej.23456","DOIUrl":"10.1002/eej.23456","url":null,"abstract":"<p>A model expressing beams, pillars, and electrical wiring in a building for lightning surge simulation by circuit analysis method is proposed in this paper. The proposed model expresses the self-surge impedance of the electrical wiring as a function of the distance between conductors and the radius of the electrical wiring. The mutual impedance is expressed by the distance between the surfaces of a structure and a nearby wire instead of the distance between the conductor centers. In the case of two conductors having far different radii in proximity, the distribution of electromagnetic fields around the two conductors is similar in horizontal and vertical arrangements. Thus, the electrical wiring nearby pillars can be treated as a horizontal conductor. The circuit analysis results show that the voltage difference generated between the structure and the electrical wiring is calculated more precisely by the proposed model than by the conventional model.</p>","PeriodicalId":50550,"journal":{"name":"Electrical Engineering in Japan","volume":"217 1","pages":""},"PeriodicalIF":0.4,"publicationDate":"2023-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138537538","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}
Iori Uda, Satoshi Ogasawara, Koji Orikawa, Koji Kobayashi, Hiroshi Yoshida, Tatsuki Kashihara, Kohei Takada
Since a motor drive system contains an inverter (high-voltage circuit) and gate drive circuits (low-voltage circit) with a switching regulator, electromagnetic noise is generated in each of these two circuits, and noise interference between these circuits can occur. This paper discusses noise interference between the high- and low-voltage circuits of an electric compressor system with an integrated mechanical and electrical structure. Analysis using LTspice shows that the experimental and analytical results are in good agreement when a very small stray capacitance occurs between the high- and low-voltage circuits. An experiment using an actual compressor showed that conducted noise above 20 MHz can be reduced by up to 10 dB by reducing the effect of stray capacitance between these circuits.
{"title":"Analysis of interference of electromagnetic noise in an electric compressor for vehicle air-conditioning systems with an integrated mechanical and electrical structure","authors":"Iori Uda, Satoshi Ogasawara, Koji Orikawa, Koji Kobayashi, Hiroshi Yoshida, Tatsuki Kashihara, Kohei Takada","doi":"10.1002/eej.23454","DOIUrl":"10.1002/eej.23454","url":null,"abstract":"<p>Since a motor drive system contains an inverter (high-voltage circuit) and gate drive circuits (low-voltage circit) with a switching regulator, electromagnetic noise is generated in each of these two circuits, and noise interference between these circuits can occur. This paper discusses noise interference between the high- and low-voltage circuits of an electric compressor system with an integrated mechanical and electrical structure. Analysis using LTspice shows that the experimental and analytical results are in good agreement when a very small stray capacitance occurs between the high- and low-voltage circuits. An experiment using an actual compressor showed that conducted noise above 20 MHz can be reduced by up to 10 dB by reducing the effect of stray capacitance between these circuits.</p>","PeriodicalId":50550,"journal":{"name":"Electrical Engineering in Japan","volume":"217 1","pages":""},"PeriodicalIF":0.4,"publicationDate":"2023-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138537541","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 paper proposes a method to select a power factor for an inverter of distributed power generation systems to keep appropriate voltage of a power system with the high penetration of inverter-interfaced generation. The increase of inverter-interfaced power sources, such as wind and photovoltaic power generation, arouses concerns on the voltage fluctuations in a power system. While constant power factor control of an inverter has been studied as a means to stabilize the voltage of a power system, there still remains room to improve the control. The proposed method in the paper selects the power factor based on the R/X ratio of the looking-back impedance into the interconnected power system. By normalizing the related variables, a general formula is derived for the power factor, and the resultant relationship between the apparent power and voltage of an inverter becomes identical irrespective of the R/X ratio with the control. Sample studies show that, by operating an inverter with the power factor, voltage fluctuations are effectively suppressed even for a power system with the high penetration of inverter-interfaced generation.
{"title":"Power factor control for inverters under high penetration of distributed generation","authors":"Yasuaki Yamada, Toshiya Nanahara, Kazuto Yukita","doi":"10.1002/eej.23452","DOIUrl":"10.1002/eej.23452","url":null,"abstract":"<p>The paper proposes a method to select a power factor for an inverter of distributed power generation systems to keep appropriate voltage of a power system with the high penetration of inverter-interfaced generation. The increase of inverter-interfaced power sources, such as wind and photovoltaic power generation, arouses concerns on the voltage fluctuations in a power system. While constant power factor control of an inverter has been studied as a means to stabilize the voltage of a power system, there still remains room to improve the control. The proposed method in the paper selects the power factor based on the <i>R</i>/<i>X</i> ratio of the looking-back impedance into the interconnected power system. By normalizing the related variables, a general formula is derived for the power factor, and the resultant relationship between the apparent power and voltage of an inverter becomes identical irrespective of the <i>R</i>/<i>X</i> ratio with the control. Sample studies show that, by operating an inverter with the power factor, voltage fluctuations are effectively suppressed even for a power system with the high penetration of inverter-interfaced generation.</p>","PeriodicalId":50550,"journal":{"name":"Electrical Engineering in Japan","volume":"216 4","pages":""},"PeriodicalIF":0.4,"publicationDate":"2023-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136034227","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}
Bus bar of substations are important equipment where multiple facilities are centrally connected, and the impact of a fault is significant. Therefore, bus bar protection relays have unique functions to correctly detect the point of fault, which allows high speed fault elimination and minimization of outage area. This paper describes functions and roles of bus bar protection relays applied in distribution substation of Kansai Transmission and Distribution. After describing the concept of installation of bus bar protection relays, recent trends in device development tailored to the bus bar configurations of substations and the unique functions of bus bar protection relays are introduced. The retrofit methods that are being increasingly applied as a renewal solution for bus bar protection relays are then described, as well as prospects for bus bar protection functions in the future IEC 61850 full-digital substations.
{"title":"Function and role of bus bar protection relay in distribution substation","authors":"Yuki Matsuda, Takayuki Inui","doi":"10.1002/eej.23451","DOIUrl":"10.1002/eej.23451","url":null,"abstract":"<p>Bus bar of substations are important equipment where multiple facilities are centrally connected, and the impact of a fault is significant. Therefore, bus bar protection relays have unique functions to correctly detect the point of fault, which allows high speed fault elimination and minimization of outage area. This paper describes functions and roles of bus bar protection relays applied in distribution substation of Kansai Transmission and Distribution. After describing the concept of installation of bus bar protection relays, recent trends in device development tailored to the bus bar configurations of substations and the unique functions of bus bar protection relays are introduced. The retrofit methods that are being increasingly applied as a renewal solution for bus bar protection relays are then described, as well as prospects for bus bar protection functions in the future IEC 61850 full-digital substations.</p>","PeriodicalId":50550,"journal":{"name":"Electrical Engineering in Japan","volume":"216 4","pages":""},"PeriodicalIF":0.4,"publicationDate":"2023-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135738592","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 energy consumption of a battery-powered train in an interstation depends on the running time and state of energy (SOE) at departure. In this paper, we develop an optimization method of train timetables to minimize energy consumption in line with several stations. The variables in this proposed optimization model are running, dwell, and charging times as real numbers and places of charging facilities as binaries. Additionally, we conducted a case study using the real-world light rail transit (LRT) route, vehicle, and onboard battery model to confirm the effectiveness. In the case study, the proposed method can optimize the timetable and placement of charging facilities by considering the track gradient and battery SOE.
{"title":"Optimization of train timetables and placement of charging facilities for battery-powered LRT","authors":"Kosuke Horiuchi, Masafumi Miyatake","doi":"10.1002/eej.23453","DOIUrl":"10.1002/eej.23453","url":null,"abstract":"<p>The energy consumption of a battery-powered train in an interstation depends on the running time and state of energy (SOE) at departure. In this paper, we develop an optimization method of train timetables to minimize energy consumption in line with several stations. The variables in this proposed optimization model are running, dwell, and charging times as real numbers and places of charging facilities as binaries. Additionally, we conducted a case study using the real-world light rail transit (LRT) route, vehicle, and onboard battery model to confirm the effectiveness. In the case study, the proposed method can optimize the timetable and placement of charging facilities by considering the track gradient and battery SOE.</p>","PeriodicalId":50550,"journal":{"name":"Electrical Engineering in Japan","volume":"216 4","pages":""},"PeriodicalIF":0.4,"publicationDate":"2023-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135828484","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 experiments of pre-ionized inert gas plasma MHD electrical power generation are conducted, and the performance and plasma behavior in the experimental generator are examined through time-dependent r-_ two-dimensional numerical simulation. In the experiment, an enthalpy extraction ratio of 4.01% has been obtained with a disk-shaped MHD generator with radio-frequency pre-ionization. In the numerical simulation, at an assumed inlet electron temperature around 5600 K (inlet ionization degree 0:10 × 10−4)_6600 K (1:36 × 10−4), the plasma structure is similar to the non-uniform structure observed in the experiment. An enthalpy extraction ratio around 2_5% matches well with that in the experiment. At a suitable inlet electron temperature of 7000 K (3:15 × 10−4)_8000 K (1:79 × 10−3), although non-uniform plasma structure still occurs, a high enthalpy extraction ratio over 10% is expected.
进行了预电离惰性气体等离子体MHD发电实验,并通过随时间的r-_二维数值模拟对实验发生器的性能和等离子体行为进行了研究。在实验中,采用圆盘型高频预电离MHD发生器,获得了4.01%的焓萃取率。在数值模拟中,假设入口电子温度约为5600 K(入口电离度0:10 × 10−4)_6600 K (1:36 × 10−4)时,等离子体结构与实验中观察到的非均匀结构相似。焓萃取比在25%左右与实验结果吻合较好。在合适的进口电子温度为7000 K (3:15 × 10−4)~ 8000 K (1:79 × 10−3)时,虽然等离子体结构仍然不均匀,但焓萃取率有望达到10%以上。
{"title":"Fundamental experiment and numerical simulation of pre-ionized inert gas plasma MHD electrical power generation","authors":"Ork Kimsor, Yoshinobu Kodera, Yoshihiro Okuno","doi":"10.1002/eej.23449","DOIUrl":"10.1002/eej.23449","url":null,"abstract":"<p>The experiments of pre-ionized inert gas plasma MHD electrical power generation are conducted, and the performance and plasma behavior in the experimental generator are examined through time-dependent r-_ two-dimensional numerical simulation. In the experiment, an enthalpy extraction ratio of 4.01% has been obtained with a disk-shaped MHD generator with radio-frequency pre-ionization. In the numerical simulation, at an assumed inlet electron temperature around 5600 K (inlet ionization degree 0:10 × 10<sup>−4</sup>)_6600 K (1:36 × 10<sup>−4</sup>), the plasma structure is similar to the non-uniform structure observed in the experiment. An enthalpy extraction ratio around 2_5% matches well with that in the experiment. At a suitable inlet electron temperature of 7000 K (3:15 × 10<sup>−4</sup>)_8000 K (1:79 × 10<sup>−3</sup>), although non-uniform plasma structure still occurs, a high enthalpy extraction ratio over 10% is expected.</p>","PeriodicalId":50550,"journal":{"name":"Electrical Engineering in Japan","volume":"216 4","pages":""},"PeriodicalIF":0.4,"publicationDate":"2023-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135538810","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}
Single-phase loads and photovoltaic generation cause three-phase imbalance in distribution systems, and prospective growth of normal chargers of electric vehicles may even increase the imbalance. The analysis of such unbalanced systems requires the three-phase power-flow calculation. Since existing methods require the admittance matrices of three-phase transformers, they must be derived for all possible winding connection patterns in advance to its computer-code implementation. This paper proposes a three-phase power-flow calculation method which formulates circuit equations using the modified nodal analysis, making it possible to automatically handle any winding connection. The power-flow constraints are then embedded into the circuit equations using a fixed-point iteration. Newton-Raphson, backward/forward sweep and fixed-point iteration methods are the existing three categories of solution methods. Newton-Raphson methods may show convergence problems due to the high R/X ratios of distribution lines. Backward/forward sweep methods cannot be used, because loops are temporarily formed in a distribution system during circuit switching. These justify the use of a fixed-point iteration. In this paper, the proposed method is validated by practical examples.
{"title":"Development of a three-phase power-flow calculation method for distribution systems with automatic handling of arbitrary winding connections of transformers","authors":"Guilherme Cirilo Leandro, Taku Noda","doi":"10.1002/eej.23445","DOIUrl":"10.1002/eej.23445","url":null,"abstract":"<p>Single-phase loads and photovoltaic generation cause three-phase imbalance in distribution systems, and prospective growth of normal chargers of electric vehicles may even increase the imbalance. The analysis of such unbalanced systems requires the three-phase power-flow calculation. Since existing methods require the admittance matrices of three-phase transformers, they must be derived for all possible winding connection patterns in advance to its computer-code implementation. This paper proposes a three-phase power-flow calculation method which formulates circuit equations using the modified nodal analysis, making it possible to automatically handle any winding connection. The power-flow constraints are then embedded into the circuit equations using a fixed-point iteration. Newton-Raphson, backward/forward sweep and fixed-point iteration methods are the existing three categories of solution methods. Newton-Raphson methods may show convergence problems due to the high R/X ratios of distribution lines. Backward/forward sweep methods cannot be used, because loops are temporarily formed in a distribution system during circuit switching. These justify the use of a fixed-point iteration. In this paper, the proposed method is validated by practical examples.</p>","PeriodicalId":50550,"journal":{"name":"Electrical Engineering in Japan","volume":"216 4","pages":""},"PeriodicalIF":0.4,"publicationDate":"2023-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135957849","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}
A linear motor that uses a finite length Halbach array as its magnetic field causes a thrust force ripple owing to end effects. In this paper, the theoretical and numerical analysis methods of the Halbach array are investigated. The results of the electromagnetic field analysis are compared to confirm the validity of the theoretical and numerical solutions. Moreover, we focus on the magnetic pole period and coil arrangement of the finite length Halbach field type linear motor to eliminate the influence of the end effects, and report the relationship with the end effects.
{"title":"End effects of Halbach field magnet-type linear motor","authors":"Hiroto Yamaguchi, Mimpei Morishita","doi":"10.1002/eej.23450","DOIUrl":"10.1002/eej.23450","url":null,"abstract":"<p>A linear motor that uses a finite length Halbach array as its magnetic field causes a thrust force ripple owing to end effects. In this paper, the theoretical and numerical analysis methods of the Halbach array are investigated. The results of the electromagnetic field analysis are compared to confirm the validity of the theoretical and numerical solutions. Moreover, we focus on the magnetic pole period and coil arrangement of the finite length Halbach field type linear motor to eliminate the influence of the end effects, and report the relationship with the end effects.</p>","PeriodicalId":50550,"journal":{"name":"Electrical Engineering in Japan","volume":"216 4","pages":""},"PeriodicalIF":0.4,"publicationDate":"2023-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86117948","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}
In this paper, a streamline display method for magnetic flux density and magnetic field strength vectors in a three-phase induction motor model core is presented, and the relationship between streamlines and magnetic properties is investigated. It is possible to visualize the vector magnetic properties distribution by representing the magnetic flux density and the magnetic field strength vector with the streamlines. In addition, the time variation of the streamlines of the magnetic flux density and magnetic field strength vectors, and magnetic energy was compared. It was clear that the magnetic energy did not necessarily increase in the areas where the magnetic flux density and magnetic field strength increased because these vectors have the spatial phase difference.
{"title":"Evaluation of vector magnetic property in a three-phase induction motor model core with visualization of streamline","authors":"Yuichiro Kai, Ryoya Maeda, Masato Enokizono","doi":"10.1002/eej.23441","DOIUrl":"10.1002/eej.23441","url":null,"abstract":"<p>In this paper, a streamline display method for magnetic flux density and magnetic field strength vectors in a three-phase induction motor model core is presented, and the relationship between streamlines and magnetic properties is investigated. It is possible to visualize the vector magnetic properties distribution by representing the magnetic flux density and the magnetic field strength vector with the streamlines. In addition, the time variation of the streamlines of the magnetic flux density and magnetic field strength vectors, and magnetic energy was compared. It was clear that the magnetic energy did not necessarily increase in the areas where the magnetic flux density and magnetic field strength increased because these vectors have the spatial phase difference.</p>","PeriodicalId":50550,"journal":{"name":"Electrical Engineering in Japan","volume":"216 4","pages":""},"PeriodicalIF":0.4,"publicationDate":"2023-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134998173","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}