著者
仲間 祐貴 タンスリヤボン スリヨン
出版者
一般社団法人 電気学会
雑誌
電気学会論文誌D(産業応用部門誌) (ISSN:09136339)
巻号頁・発行日
vol.143, no.2, pp.132-138, 2023-02-01 (Released:2023-02-01)
参考文献数
11

One of the impacts of COVID-19 is the exponential growth of online classroom teaching. However, grasping the reaction and understanding of the students in an online classroom is difficult for the teachers. This is especially a problem in Project Based Learning (PBL) courses with practical exercises. This study provides a “place” to share information about problems encountered by each student. Other students can then use this information to perform practical exercises remotely. As a result, we were able to identify bottlenecks in the exercise tasks by creating “empathize with problems” among students.
著者
竹下 隆晴 野村 尚史 松井 信行
出版者
The Institute of Electrical Engineers of Japan
雑誌
電気学会論文誌D(産業応用部門誌) (ISSN:09136339)
巻号頁・発行日
vol.115, no.4, pp.420-427, 1995-03-20 (Released:2008-12-19)
参考文献数
10
被引用文献数
5 11

This paper presents a position sensorless drive of a brushless dc motor with a sinusoidal flux distribution. The estimation of position and emf is performed by using the integration of the current differences between the actual motor and model. The estimation speed is calculated by the differential calculus of the estimated position. The stability of the proposed algorithm and the design of the estimation gains are explained and it is shown that the parameter differences do not give serious effects on the estimation characteristics.In the experimental results using a 6-pole 1.2kW test motor, the speed control range from 35 to 1500rpm is obtained. To verify the proposed algorithm, the estimation and speed control characteristics are shown. Furthermore, the starting characteristics of the motor from arbitrary rotor position are shown.
著者
堀 洋一 澤田 英行 全 瑩煥
出版者
The Institute of Electrical Engineers of Japan
雑誌
電気学会論文誌D(産業応用部門誌) (ISSN:09136339)
巻号頁・発行日
vol.117, no.1, pp.50-56, 1996-12-20 (Released:2008-12-19)
参考文献数
10
被引用文献数
6 8

In the resonance ratio control, which is a well-known excellent technique for vibration suppression and disturbance rejection control of torsional systems, the estimation speed of the disturbance observer was assumed to be much faster than the resonance frequency of the controlled object. However, too fast disturbance observer sometimes causes implementation problem. In this paper, we give the optimal speed of the disturbance estimation and propose a novel technique, “slow resonance ratio control”. It enables us to design the speed controller and the vibration suppression controller completely independently.
著者
冨田 睦雄 道木 慎二 大熊 繁
出版者
The Institute of Electrical Engineers of Japan
雑誌
電気学会論文誌D(産業応用部門誌) (ISSN:09136339)
巻号頁・発行日
vol.115, no.6, pp.765-774, 1995-05-20 (Released:2008-12-19)
参考文献数
11
被引用文献数
1 3

It has been known that a state equation of a blushless DC motor is a nonlinear one. Recently, new linear state equation and a position and velocity sensorless control system with the full-order observer based on the equation has been proposed. But the pole assignment of the observer has not been presented clearly. In this paper, we propose an adaptive sliding observer for this linear state equation and present clearly the pole assignment of the sliding observer for robust flux estimation with estimated velocity error. The simulation shows that the proposed system is very useful.
著者
榎倉 浩志 井上 征則 森本 茂雄 真田 雅之 會澤 敏満 高木 隆志
出版者
一般社団法人 電気学会
雑誌
電気学会論文誌D(産業応用部門誌) (ISSN:09136339)
巻号頁・発行日
vol.142, no.5, pp.393-399, 2022-05-01 (Released:2022-05-01)
参考文献数
15

This paper proposes a novel torque controller in a direct torque control (DTC) system for permanent magnet synchronous motors (PMSM). A reference flux vector calculation (RFVC) DTC uses a PI controller for torque control and can be applied with a PWM voltage-fed inverter. The RFVC DTC's controller can be designed using classical control theory with a linear transfer function by analyzing the relationship between the torque, torque angle, rotor speed, and angular frequency of the stator flux-linkage vector. In contrast, the conventional equivalent modeling method is only applicable with high control gain. At a lower control gain, the convergence performance degrades in the conventional model. Therefore, the torque control characteristics are improved by the proposed system, which is based on the decoupling rotor speed in the torque control system. Simulation and experimental results confirm the validity of the proposed system.
著者
南 政孝 茂木 進一 道平 雅一
出版者
一般社団法人 電気学会
雑誌
電気学会論文誌D(産業応用部門誌) (ISSN:09136339)
巻号頁・発行日
vol.139, no.2, pp.NL2_10, 2019-02-01 (Released:2019-02-01)

Our laboratory focuses on power electronics, energy storage applications, and renewable energy systems.
著者
黒田 浩司 岡井 文彦 高野 和朗
出版者
一般社団法人 電気学会
雑誌
電気学会論文誌. D, 産業応用部門誌 = The transactions of the Institute of Electrical Engineers of Japan. D, A publication of Industry Applications Society (ISSN:09136339)
巻号頁・発行日
vol.125, no.3, pp.286-292, 2005-03-01
参考文献数
9
被引用文献数
3 2

The 76GHz millimeter wave radar has been developed for automotive application such as ACC (Adaptive Cruise Control) and CWS (Collision Warning System). The radar is FSK (Frequency Shift Keying) monopulse type. The radar transmits 2 frequencies in time-duplex manner, and measures distance and relative speed of targets. The monopulse feature detects the azimuth angle of targets without a scanning mechanism. Conventionally a radar unit is aimed mechanically, although self-aiming capability, to detect and correct the aiming angle error automatically, has been required. The new algorithm, which estimates the aiming angle error and vehicle speed sensor error simultaneously, has been proposed and tested. The algorithm is based on the relationship of relative speed and azimuth angle of stationary objects, and the least squares method is used for calculation. The algorithm is applied to measured data of the millimeter wave radar, resulting in aiming angle estimation error of less than 0.6 degree.
著者
福田 典子 田口 義晃 小笠 正道
出版者
一般社団法人 電気学会
雑誌
電気学会論文誌D(産業応用部門誌) (ISSN:09136339)
巻号頁・発行日
vol.139, no.10, pp.854-862, 2019-10-01 (Released:2019-10-01)
参考文献数
26
被引用文献数
4

The purpose of this study is to develop power circuits for AC electric trains with weight reduction and downsizing. We devised a new power circuit configuration which uses SiC modules for insulation function instead of the main transformers, manufactured the circuit models on an experimental basis, and executed the verification. The results verified the bidirectional operation, demonstrating that about a 5.7kW of power was transmitted for the input voltage of up to 200V and the switching frequency of 20kHz run, while ensuring the insulation state without any simultaneous conduction between the primary and secondary terminals through the flying capacitor.
著者
藤田 英明 萩原 誠 赤木 泰文
出版者
The Institute of Electrical Engineers of Japan
雑誌
電気学会論文誌. D, 産業応用部門誌 = The transactions of the Institute of Electrical Engineers of Japan. D, A publication of Industry Applications Society (ISSN:09136339)
巻号頁・発行日
vol.132, no.6, pp.659-665, 2012-06-01
被引用文献数
4 25

This paper discusses the power flow analysis and dc-capacitor voltage regulation for the modular multilevel cascaded converter (MMCC) based on double-star chopper cells (DSCC). This analysis reveals the relationship between the circulating current through the dc link and the mean power flowing out of or into each chopper cell. The dc component on the circulating current supplies a half of the active output power to the upper and lower strings of chopper cells, whereas the fundamental-frequency component transfers an amount of power between the upper and lower strings. Thus, the MMCC-DSCC can balance the capacitor voltages among the cells by controlling the amplitude of the fundamental-frequency component on the circulating current. A new control method based on the power flow analysis is employed, and its effectiveness is verified by circuit simulation.
著者
外山 浩司 竹下 隆晴 松井 信行
出版者
The Institute of Electrical Engineers of Japan
雑誌
電気学会論文誌D(産業応用部門誌) (ISSN:09136339)
巻号頁・発行日
vol.117, no.8, pp.1033-1038, 1997-07-20 (Released:2008-12-19)
参考文献数
9
被引用文献数
2 5

PWM control is promising to achieve a unity power factor and to improve the input current distortion in a high performance current-source three-phase AC/DC converter system. In contrast to the voltage-source converter, the LC filter connected between the source and the converter may cause an LC resonance both in steady and transient states. Many reports have been published to improve the current distortion in steady state and to suppress the current oscillation in transient state of the current-source PWM converter by using the feedback control.This paper gives an analysis of the transient oscillation of the filter voltage and current, and proposes a simple open-loop suppression method by using the rate limiter of the input current reference. Furthermore, the design rule of the LC filter for the suppression control of the transient oscillation is described. The effectiveness of the proposed approach has been verified by experiments.
著者
貝森 弘行 岡本 吉史 若尾 真治
出版者
一般社団法人 電気学会
雑誌
電気学会論文誌D(産業応用部門誌) (ISSN:09136339)
巻号頁・発行日
vol.139, no.4, pp.380-387, 2019-04-01 (Released:2019-04-01)
参考文献数
15
被引用文献数
1

Recently, from the viewpoint of vibration and noise reductions, torque ripple reduction of motor-equipped electrical machines is the need of the hour. The authors have already proposed to improve torque characteristics of a synchronous reluctance motor using the topology optimization method. The evaluated rotor structure succeeded in substantial torque ripple reduction, but the cause for this reduction was unknown. In this paper, we investigate the reason for torque ripple reduction using the improved rotor structure of the motor by a topology optimization method known as R-SLP, by comparing it to the reference model using finite element analysis. A calculation method is proposed to analyze the circumferential magnetic force density of spatial and time harmonic orders using the magnetic density in the air gap. By focusing on the time order at which the torque waveform was evaluated, we estimate which circumferential magnetic force density orders affect torque ripple reduction. Then, we clarify the reason for torque ripple reduction to examine the influence of local shape of rotor structure using 12th time-harmonic magnetic fields. As a result, the modified flux barrier rotor structure is obtained, which further reduces the torque ripple in comparison to the previous structure.
著者
陳 志謙 冨田 睦雄 千住 智信 道木 慎二 大熊 繁
出版者
The Institute of Electrical Engineers of Japan
雑誌
電気学会論文誌D(産業応用部門誌) (ISSN:09136339)
巻号頁・発行日
vol.118, no.7-8, pp.828-835, 1998-07-01 (Released:2008-12-19)
参考文献数
7
被引用文献数
8 7

The equation of brushless dc motors is nonlinear, to which linear control theories are difficult to apply. In this paper, firstly, a disturbance observer to estimate rotor positions is proposed. By assuming the non-linear term of the e. m. f. as a kind of disturbance, the model of the brushless dc motors becomes a linear one so that the disturbance observer can be applied. Secondly, a velocity estimator using the e. m. f. estimated by the disturbance observer is proposed. The observer and estimator are 2nd-order systems. Thus they are simple and easy for tuning. Their pole assignments and influences of parameter deviations are also discussed. The experimental results show that the proposed method is valid.
著者
綱田 錬 竹本 真紹 小笠原 悟司 折川 幸司 齋藤 達哉 上野 友之
出版者
一般社団法人 電気学会
雑誌
電気学会論文誌D(産業応用部門誌) (ISSN:09136339)
巻号頁・発行日
vol.140, no.12, pp.939-948, 2020-12-01 (Released:2020-12-01)
参考文献数
24
被引用文献数
5

In recent years, more than half of the electric power generated in the country is being consumed by motors. Therefore, high performance motors are desired especially for industrial applications. In addition, it is desirable to reduce motor size. Recently, motors called axial gap type have been proposed and researched to achieve both high torque and small size. Axial gap motors are generally suitable for applications requiring flat shape such as a disk. Conventional axial gap motors frequently employ Nd sintered permanent magnets (PMs) to achieve high torque. However, axial gap motors with Nd sintered PMs are not very efficient at high rotational speed due to the eddy current loss arising in the PM. Axial gap motors that use ferrite PMs have also been proposed, but torque density is low. In this paper, an axial gap motor using Nd bonded PMs is proposed to achieve high efficiency in the high-speed and high-torque region. The proposed axial gap motor using Nd bonded PM is compared with other axial gap motors employing Nd sintered PM and ferrite PM through 3D-FEA and experiments. Consequently, it was found that the Nd bonded PM is more effective in enhancing the efficiency of an axial gap motor in the high-speed and high-torque region, compared with Nd sintered PM and ferrite PM.
著者
楊 耕 富岡 理知子 中野 求 金 東海
出版者
The Institute of Electrical Engineers of Japan
雑誌
電気学会論文誌D(産業応用部門誌) (ISSN:09136339)
巻号頁・発行日
vol.113, no.5, pp.579-586, 1993-05-20 (Released:2008-12-19)
参考文献数
11
被引用文献数
34 63

A permanent magnet synchronous motor can be controlled as a DC brushless motor, for which the position sensor is needed for detecting the rotor position. In this paper, the research on speed control system without position and speed sensors is reported, where the rotor position and speed of the motor are estimated by means of an adaptive observer. To make the state equations linear, two new state variables are introduced. Consequently, based on the Iinear control theory, an adaptive observer is designed by which the estimated speed and position are converged to real ones. The system is verified to be asymptotically stable. The operation of the system at zero speed and the effects of the mismatched parameters used in the observer are also discussed. Finally, the speed control of the system is implemented. The computer simulation and the experiments show that the system is valid.
著者
三井 晃司 和田 圭二
出版者
一般社団法人 電気学会
雑誌
電気学会論文誌D(産業応用部門誌) (ISSN:09136339)
巻号頁・発行日
vol.140, no.11, pp.817-825, 2020-11-01 (Released:2020-11-01)
参考文献数
45
被引用文献数
1

In a power converter circuit, it is well known that the bus bar structure affects both surge voltage and switching loss. However, the bus bar structure may be one of the causes for the oscillation waveform to induce electromagnetic interference (EMI) issues. This study proposes a design procedure of an optimized bus bar structure. Since the parasitic parameters of the bus bar geometory, such as inductance, capacitance, and resistance, are complicated in the megahertz frequency range, the parasitic parameters that have frequency characteristics are analyzed by the finite element method. The surge voltage and oscillation voltage under a turn-off operation are evaluated by using the bus bar modeled as S-parameters. It demonstrated that the optimal bus bar structure can reduce the surge voltage and oscillation. In accordance with the method to design an optimal bus bar, bus bar prototypes are designed, and the experimental results rated at 400V, 30A are presented to verify the analysis and simulation.
著者
田中 拓郎 高橋 久
出版者
一般社団法人 電気学会
雑誌
電気学会論文誌D(産業応用部門誌) (ISSN:09136339)
巻号頁・発行日
vol.128, no.8, pp.1037-1043, 2008-08-01 (Released:2008-08-01)
参考文献数
19
被引用文献数
1 3

In some motor applications, it is very difficult to attach a position sensor to the motor in housing. One of the examples of such applications is the dental handpiece-motor. In those designs, it is necessary to drive highly efficiency at low speed and variable load condition without a position sensor. We developed a method to control a motor high-efficient and smoothly at low speed without a position sensor. In this paper, the method in which permanent magnet synchronous motor is controlled smoothly and high-efficient by using torque angle control in synchronized operation is shown. The usefulness is confirmed by experimental results. In conclusion, the proposed sensor-less control method has been achieved to be very efficiently and smoothly.