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Volume 128, Issue 1
Displaying 1-11 of 11 articles from this issue
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Paper
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Ikuo Yasuoka, Yasuhumi Mochizuki, Shin-ichi Toda, Yosuke Nakazawa, Hon ...2008 Volume 128 Issue 1 Pages 1-7
Published: January 01, 2008
Released on J-STAGE: January 01, 2008
JOURNAL FREE ACCESSWe have developed a re-adhesion control algorithm of traction inverter for individual Motor control locomotives. This paper describes improvement for wheel slip and re-adhesion control for individual axle electric locomotives. Major torque control is making feedback the difference between locomotive basic speed and individual axle speed. By combining two torque control methods, we have got the better re-adhesion characteristic as follows, a little influence of dynamic axle load transfer and a high available coefficient of adhesion more than 30%. We estimated these torque control by the test run and show the stability limit of feedback gain.View full abstractDownload PDF (1279K) -
Shinji Shinnaka2008 Volume 128 Issue 1 Pages 8-17
Published: January 01, 2008
Released on J-STAGE: January 01, 2008
JOURNAL FREE ACCESSThis paper presents new analyses of convergence characteristics of the D-state-observer using speed estimate with huge error for sensorless drive of permanent-magnet synchronous motors, and demonstrates high convergence performance of the D-state-observer through experiments. It is analytically shown that the maximum error of steady-state phase estimate by the D-state-observer can remain within ±π/4(rad) even if the speed estimate with huge constant error is used in the observer. The experiments demonstrate that the D-state-observer accompanied with the generalized integral-type PLL method can estimate correctly actual phase and speed of the rotor in all sensorless operation range even if the estimations start with huge initial errors.View full abstractDownload PDF (1945K) -
Takahiko Kobayashi, Yoshihiko Kimpara, Masahiro Fukuta, Takumi Ohnuma2008 Volume 128 Issue 1 Pages 18-26
Published: January 01, 2008
Released on J-STAGE: January 01, 2008
JOURNAL FREE ACCESSIn the induction motor drive using sensorless control or vector control, the control calculation is performed based on motor constants. Motor constants are obtained by no load test and lock test. However no load test and lock test are inapplicable to the induction motors joined to machines.
This paper suggests the novel method of motor constants measurement without rotating for induction motors. The feature of this novel method is measuring only imaginary part of equivalent impedance of T type equivalent circuit of the induction motor on stop state by supplying the low frequency alternating voltage when measuring mutual inductance and rotor resistance. The reason is because the measured value of the real part of equivalent impedance is not exact because of the error of stator resistance and the voltage error which the dead time causes.
It was confirmed by the experiment that this novel method enables to set control parameters correctly and to drive stably induction motors joined to machines with speed sensorless vector control.View full abstractDownload PDF (727K) -
Toshihiko Noguchi, Somei Nakatomi2008 Volume 128 Issue 1 Pages 27-33
Published: January 01, 2008
Released on J-STAGE: January 01, 2008
JOURNAL FREE ACCESSThis paper proposes a novel control strategy of a matrix converter, which features direct instantaneous active- and reactive-power control of the converter. A theoretical aspect of the proposed control is discussed, and some computer simulation results are presented to confirm the basic controllability of the technique. In addition, several operation characteristics are examined through experimental tests, using a 1.5-kW prototype. The maximum efficiency and the total input power factor of the prototype were 95.4% and 99.9% at 1.5-kW load with 30-Hz output frequency, respectively. Furthermore, the total harmonic distortion at the rated load was 5.9%. These results prove feasibility and effectiveness of the proposed strategy.View full abstractDownload PDF (762K) -
Hirokazu Fukui, Eiji Hiraki, Toshihiko Tanaka, Shinji Fukuma2008 Volume 128 Issue 1 Pages 34-40
Published: January 01, 2008
Released on J-STAGE: January 01, 2008
JOURNAL FREE ACCESSThis paper proposes a new control method of the current balancer for single-phase three-wire secondary distribution systems using the correlation and cross-correlation coefficients. The components of the load currents correlative and cross-correlative to the primary side voltage waveform, which correspond to the active and reactive currents, are detected in each feeder, then the reactive and unbalanced-active components are compensated on the source side. The balanced currents with the variable power factor are obtained in each feeder. The basic principle of the proposed method is discussed in detail, and then confirmed by digital computer simulation. A proto-type experimental system is constructed and tested. Experimental results demonstrate that the balanced source currents with the power factor of 0.9 are obtained in spite of unbalanced load currents.View full abstractDownload PDF (674K) -
Naoki Oda, Hiroyuki Shimizu2008 Volume 128 Issue 1 Pages 41-47
Published: January 01, 2008
Released on J-STAGE: January 01, 2008
JOURNAL FREE ACCESSThis paper describes a vision based self-velocity estimation and its feedback system under force/torque sensor-less power assisting control of wheelchair robot. In this method, three dimensional information obtained by stereo images, and the optical flow vectors are also used for self-velocity estimation in real-time. The human force is estimated by sensor-less reaction force observer, and the assisting force is calculated by using its estimated force and virtual impedance model. In the paper, the force based assist function is integrated into visual feedback motion controller. This approach using vision and force based assist control makes it possible to facilitate the direct intelligent interactions between human force and environments such as human following assist, obstacle avoidance one and so on. Such assist functions are changeable by the selection of the weighting matrix in the velocity estimation, which is based on weighted least square solutions from optical flow vectors. The validity of the proposed approach is verified by several experimental results.View full abstractDownload PDF (1103K) -
Takahiro Hoshino, Kousuke Inoue, Kazuhiro Tsuboi, Yoshio Hamamatsu2008 Volume 128 Issue 1 Pages 48-55
Published: January 01, 2008
Released on J-STAGE: January 01, 2008
JOURNAL FREE ACCESSThis paper deals with a merging section of Personal Rapid Transit system with bulk arrival. Vehicles arrive at a merging section from a main line and a sub line. In most of the previous studies on PRT system, vehicles on the main line have priority. Then, a queue is formed only on the sub line. In this situation, the queuing delay on the sub line may become extremely long. We propose a control strategy whereby vehicles on the main line are not stopped in normal situation; vehicles on the main line are only stopped when the number of waiting vehicles on the sub line exceeds some specific number. This specific number is a sort of threshold. Thus, queues are formed on the main line and the sub line, respectively. Both of the queuing delays are controlled with the threshold. The optimal value of the threshold can be obtained by analyzing the stochastic model. By the optimal value, we can set the rate of queuing delay between the main and sub lines to an arbitrary rate.View full abstractDownload PDF (648K) -
Katsumi Yamazaki, Yuta Watanabe2008 Volume 128 Issue 1 Pages 56-63
Published: January 01, 2008
Released on J-STAGE: January 01, 2008
JOURNAL FREE ACCESSIn this paper, we investigate the main factors of stray load loss of cage induction motors from both results of measurement and electromagnetic field analysis. The losses generated at the rotor cage, stator and rotor cores are calculated by the combined 3-D-2-D finite element analysis considering the magnetic saturation and harmonics, which vary due to the load condition. On the other hand, the total and stray load losses of the motor are measured due to IEEE standard 112. The relationship between the measured losses and the practical losses generated at each part of the motor are investigated from these results. It is clarified that the main part of the stray load loss in case of the analyzed motor is the increase of the harmonic losses due to load, which are the harmonic rotor cage losses and harmonic core losses including the inter-bar current losses.View full abstractDownload PDF (1676K) -
Masashi Yokoi, Tadashi Fukami, Kazuo Shima, Ryoichi Hanaoka, Shinzo Ta ...2008 Volume 128 Issue 1 Pages 64-70
Published: January 01, 2008
Released on J-STAGE: January 01, 2008
JOURNAL FREE ACCESSThis paper presents a novel type of dual-winding reluctance generator (DWRG) which uses a multiple-barrier (MB) rotor. The stator of the DWRG is equipped with an armature winding and a field winding. By changing the stator field current, the constant voltage control is easily achieved over a wide range of speeds. The structure and operating principle of the DWRG are described, and its performance is evaluated by the equivalent circuit approach, finite-element (FE) analysis, and experiments conducted on a prototype machine. Compared to a salient-pole (SP) rotor used in a conventional DWRG, the studied MB rotor provides good magnetic coupling between the two stator windings and was found to have great potential as a DWRG rotor.View full abstractDownload PDF (1213K) -
Nobuhiko Hatano, Yuji Taniguchi, Katsuhiko Kouchi2008 Volume 128 Issue 1 Pages 71-82
Published: January 01, 2008
Released on J-STAGE: January 01, 2008
JOURNAL FREE ACCESSInverter which is used for distributed power supply, such as solar cell or fuel cell system, tends to stop easily by voltage sag. In the present electric power system, there is little problem by this characteristic of inverter. But if the number of those inverters connected to power system increases, the quality of system voltage and frequency may deteriorate by stop of the inverters. In addition, about fuel cell system, its output power cannot be controlled quickly, and the whole system may stop by a rise of inside temperature.
For these problems, we tried to realize high continuous operation ability of inverter used for distributed power supply under voltage sag condition. This paper shows a control method of inverter for the over current caused by sudden change or unbalance of the system voltage and examination results with 3-phase 200V-4kW class inverter system.View full abstractDownload PDF (1207K)
Letter
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Katsumi Kesamaru, Yoshihiro Ohno, Daisuke Sonoda2008 Volume 128 Issue 1 Pages 83-84
Published: January 01, 2008
Released on J-STAGE: January 01, 2008
JOURNAL FREE ACCESSThe paper describes a new approach to simulate the small wind power generating systems using PMSG, in which the output is connected to constant resistive load, such as heaters, through the rectifier and the dc chopper. The dynamics of the wind power generating system is presented, and it is shown by simulation results that this approach is useful for system dynamics, such as starting phenomena.View full abstractDownload PDF (289K)
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