Since the advent of railway vehicles with three-phase drive in the 1970s, power semiconductors used in electric railway vehicles have been changed from thyristors to GTO thyristors and IGBTs. As for traction motor control, vector control has come into wide use in place of slip frequency control and vector control without speed sensor is at a trial stage for commercial trains. Anti-slip and readhesion control of railway vehicles has greatly progressed by utilizing wheel axle speed information. Locomotives and electric multiple units with speed-sensor-less vector control in the future should have at least the same adhesion performance as that of the alternatives with speed sensor.
In this paper, a novel anti-slip readhesion control without speed sensor is proposed. By this method small wheel slips can be easily detected. Its performance is expected to be as high as that of the control with speed sensor. This paper enumerates the characteristics of wheel slip phenomenon and anti-slip control for railway vehicles, explains the running test results that show basics of anti-slip readhesion control with speed sensors, describes an outline of the novel anti-slip readhesion control without speed sensor, and verifies the basic functions by simulation.

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The influence of strict defect control is both the enhancement of manufacturing yield and the delivery delay due to the drop of the machine operation rate. Therefore defect inspection method must be optimized for this trade-off especially for ASIC manufacturing. In the first report, we proposed a new cost model which treats not only inspection and yield model but also and workflow model. In this report, we formularize the inspection parameter dependance on manufacturing yield and machine cleaning cycle that may affect delivery time. With the formula, factory engineers can get practical information for inspection parameter optimization.

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A new approach for real time digital feedback control of PWM inverter is proposed, in which an instantaneous value control with filter capacitor current compensation is achieved.In this scheme, the sampling frequency of the inverter becomes half of the carrier frequency, and it is suitable to implement for higher carrier frequency.
In this paper, the output characteristics of the inverter for various LC filter components are evaluated.From the view point of UPS applications, the advantages and disadvantages are discussed though simulations and experiments, the superiority of the proposed control law is verified.

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In this paper, the conducted emission characteristics of an active snubber boost converter with proposed timing diagram are investigated and compared with its conventional boost converter. It is illustrated theoretically and experimentally that the soft switching technique can reduce the high switching dv/dt and di/dt rate, as well as the conducted emission noise spectra generated from the hard-switched counterpart effectively. The presented active snubber boost converter shows the line to ground and the neutral to ground conducted emission spectra significantly be improved at high frequency range over the hard-switched operation.

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The methods to stabilize power sources, which are the measures against voltage drop, power loading fluctuation, regeneration power lapse and so on, have been important issues in DC feeding circuits. Therefore, an energy storage medium that uses power efficiently and reduces above-mentioned problems is much concerned about. In recent years, development of energy storage medium is remarkable for drive-power supplies of electric vehicles. A number of applications of energy storage, for instance, battery and flywheel, have been investigated so far.
A large-scale electric double-layer capacitor which is rapidly charged and discharged and offers long life, maintenance-free, low pollution and high efficiency, has been developed in wide range. We have compared the ability to charge batteries and electric double-layer capacitors. Therefore, we carried out fundamental studies about electric double-layer capacitors and its control. And we produced a prototype of energy storage for the DC electric railway system that consists of electric double-layer capacitors, diode bridge rectifiers, chopper system and PWM converters. From the charge and discharge tests of the prototype, useful information was obtained. This paper describes its characteristics and experimental results of energy storage system.

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This paper proposes a realization of motion control based on dynamic torque compensation and two-degrees-of-freedom speed control system. In order to suppress the dynamic torque of robot manipulator quickly, this paper constructs the feedforward torque compensation method based on inverse dynamics calculation on each joint control system.Moreover, the proposed joint control system is constructed by the robust control system based on the state feedback, PI speed controller and feedforward controller.The proposed method can suppress the influence of inertia variation and torsional vibration of joint system quickly and completely.The simulation results and experimental results show that the proposed system well regulates the motion of multi-joint robot and suppresses the torsional vibration.

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With respect to PWM algorithm for a three-phase voltage-source ac/dc power converter various studies have been executed and their results have been published since the analog modulation scheme based on triangular carrier wave was proposed in 1960's. PWM algorithm can be considered the heart of the electronic power conversion.
Along with progress and evolution of digital technology gate signals are increasingly requested to be generated directly by digital IC, e.g. MPU, DSP or FPGA/CPLD. The paper analyzes quantitatively the precision of the current controllability of digital PWM taking into account of both the sampling period and the delay time the latter of which is inevitably accompanied by digital procedure. The delay time is pointed out to affect the current error double. In addition the paper derives theoretically the condition for digital PWM to accomplish PPCR (Pulse Polarity Consistency Rule, i.e. the next gate command moves only to the adjacent ones). In so far as the authors know no paper offers the mathematical requirements to execute PPCR taking account of the effect by the delay time with digital PWM.
The derived theoretical results are summarized as the digital PWM design criteria for a three-phase PWM converter in order to facilitate practical implementation of the theory, which guarantee the PPCR behavior as well as the quantitative preciseness of the current regulation.

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This paper describes a method to analyze harmonic components of the air-gap flux density distribution on 3-phase cage induction motors, considering the influence of circumferential slot arrangement, stator winding pattern and distribution of air-gap permeance by magnetic saturation. The applied method is based on an analytical model of the permeance and the magnetomotive force distributions.
The proposed method is applied to the analysis of a cage induction motor at no-load and full-load conditions. As a result, the harmonic components of the air-gap flux density distributions at different driving conditions are shown quantitatively. The proposed method is also confirmed by using the numerical analysis method (finite element method). From the comparison of these calculated results, the proposed method is shown to be appropriate and useful for quantitative estimation of harmonic flux for cage induction motors.

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In this paper, the authors describe a practical calculation method of armature strand current distributions and circulating current losses for large turbine generators. A chain of analysis is made up of automatic mesh generation, a quasi three-dimensional linkage flux calculation and an armature strand network calculation. The calculated total armature coil losses for a 200MVA class turbine generator shows good agreement with detailed calculation results obtained by full three-dimensional magnetic field analysis.

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This paper presents a standstill thrust characteristics analysis of a linear induction motor (LIM) with two armatures using the 3-D finite element method (3-D FEM) with edge elements taking eddy currents into account. In this paper, we try to use a combination technique of the complex calculation and the step-by-step calculation in order to reduce the CPU time. It is clarified that the usefulness of the technique and the validity of the 3-D FEM by comparison of the calculated and measured results. Furthermore, the effects of the phase difference and frequency difference between two exciting currents of the linear induction motor with two armatures on the standstill thrust are investigated.

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This paper proposes a new simulation method for contact loss when high voltage bus cables are used in a DC feeding system. To reduce the arcs caused by contact loss, two pantographs are connected by high voltage bus cables which make a closed circuit with a contact wire and pantographs. However, it has not sufficiently been made clear that the increase of this closed circuit inductance as well as pantograph current lessens arc reducing effects. Although the current collecting performance of overhead contact-line-pantograph systems is evaluated by contact loss when high voltage bus cables are used, the detecting accuracy of contact loss measuring methods has not quantitatively been investigated either. The author has developed a simulation method for contact loss having an exponential distribution, and revealed quantitatively the amount of arc reduction and the detecting accuracy of contact loss measuring methods by applying this simulation method.

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Based on the decoupled-control method of attractive-normal and thrust forces, a compact combined-levitation-and-propulsion single-sided linear induction motor (SLIM) maglev vehicle system can be realized without any additional levitation magnets. In this paper, we have proposed a mass-reduced mode control of the SLIM vehicle based on its decoupled-control method and succeeded in a stable propulsion control experiment in 95%-mass-reduced mode at a minimum airgap-length of 1.7mm limited by guide-rollers even by using a simple construction of wheel and rail system without primary suspension. The vehicle has been propelled with the minimum power for supporting the vehicle by realizing simultaneously the minimum airgap and the soft-touch, so that it has been driven with small noises and vibrations because of very soft contact. And considering the wear and the maintenance, this running method with soft-touch mass-reduced control is very useful for many practical applications.

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In this paper, Genetic Algorithms (GAs) have been applied to designing the arrangement of utility poles. There are two purposes of this study. One is to lower the construction cost, i.e., to reduce the number of necessary utility poles. Another goal is to eliminate designer’s load to some extent.
In our method, the arrangement is determined with the following three steps: (1) Determine the arrangement of utility poles necessary for supplying the electric power to each customer. (2) Obtain the positions of other utility poles required to support electric wires by searching for the route of electric wires. (3) Adaptively tune the arrangement and the number of utility poles.
Experimental results show that the method is more effective in designing for utility poles than the usual approach. The simulation domains include realistic areas with various characteristics. We can confirm that the above two goals are achieved satisfactorily.

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In the field of the rolling stock traction system, it is demanded to suppress the slip-slide phenomenon between wheels and rails for the purpose of providing passengers comfortable ride feelings and keeping the train time schedule even in rainy days. One solution for this demand is to adopt both the re-adhesion control and the vector control. Considering this situation, we have already developed a high performance motor drive method for the rolling stock traction system, in which a single inverter drives multiple induction motors by adopting a novel stator-flux-oriented vector control. In this paper, we propose a novel re-adhesion control method for the single-inverter multiple-induction-motors drive system. The proposed method is investigated through simulations, in which the unbalanced condition of the motor load and speed caused by the differences of the wheel diameters are taken into account. Then the experimental results are brought about, which are obtained from a miniature experimental equipment capable of simulating the real rolling stock traction system in terms of the wheel diameter differences and the adhesion between the wheels and rails.

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Position sensorless control system using adaptive observer of PM motor was developed.But the adaptive observer design method of PM motor suggested already has problem in a characteristic at a high-speed region.
This paper gives a design method of the adaptive observer to solve this problem.In addition, this paper suggests technique to transform the adaptive observer of PM motor on a standstill coordinate into the observer on a rotational coordinate.Finally, we can confirm by an experiment thatproposed method shows good characteristics.

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Recently, as for the machine tools or industrial robots, high performance, accuracy, etc. are demanded. Generally, when drive of many degrees of freedom is required in the machine tools or industrial robots, it has realized by using two or more motors. For example, two-dimensional positioning stages such as the X-Y plotter or the X-Y stage are enabling the two-dimensional drive by using each one motor in the direction of x, y. In order to use plural motors, these, however, have problems that equipment becomes large and complicate control system. From such problems, the Surface Motor (SFM) that can drive two directions by only one motor is researched. Authors have proposed SFM that considered wide range movement and the application to a curved surface. In this paper, the characteristics of the micro step drive by the open loop control are showed. Introduction of closed loop control for highly accurate positioning, moreover, is examined. The drive characteristics by each control are compared.

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Automatic Train Control (ATC) in the railway signalling system is required high safety, high availability, reduction of unit, energy saving and cost reduction. This paper described the resources communization redundancy of the ATC system that shared the redundant units in preparation for common use units in order to accommodate with this issue by keeping safety and availability in the same level of conventional ATC. It was evaluated on N+2 redundant system which established 2 spares for the common use system N piece in transmission division. It was done the safety evaluation of the N+2 redundant system by way of hazard analysis of FTA method and safety issue was confirmed by FMEA. The new redundant system concludes that 19% of downsizing and 36% of the energy saving are surely possible.

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A 4H-SiC pin diode with improved termination named mesa JTE has been developed and a high blocking voltage of 6.2kV and a low V_F of 4.7V at 100A/cm² have been achieved. A developed diode has a short reverse recovery time of 28.5ns at room temperature. By evaluation of reverse recovery characteristics, a developed diode has a minority carrier lifetime of longer than 1μs at 350°C in spite of a minority carrier lifetime of 64ns at room temperature. Furthermore, a developed diode has 1/29th lower recovery loss than those of a commercialized 4.5kV Si diode.

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Advanced safety vehicle(ASV)assists drivers’ manipulation to avoid trafic accidents. A variety of researches on automatic driving systems are necessary as an element of ASV. Among them, we focus on visual feedback approach in which the automatic driving system is realized by recognizing road trajectory using image information. The purpose of this paper is to examine the validity of this approach by experiments using a radio-controlled car. First, a practical image processing algorithm to recognize white lines on the road is proposed. Second, a model of the radio-controlled car is built by system identication experiments. Third, an automatic steering control system is designed based on H_∞ control theory. Finally, the effectiveness of the designed control system is examined via traveling experiments.

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The millimetre wave radar has been developed for automotive application such as ACC (Adaptive Cruise Control) and CWS (Collision Warning System). The radar uses MMIC (Monolithic Microwave Integrated Circuits) devices for transmitting and receiving 76 GHz millimetre wave signals. 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. The Zoom FFT (Fast Fourier Transform) algorithm, which analyses frequency domain precisely, has adapted to the radar for discriminating multiple stationary targets. The Zoom FFT algorithm is evaluated in test truck. The evaluation results show good performance on discriminating two stationary vehicles in host lane and adjacent lane.

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Incandescent lamps may be employed to evaluate photovoltaic generation systems in laboratory. The lamps energized by unregulated power supplies are inappropriate for the proper evaluation. This paper proposes a new power supply for the lamps without power ripples owing to using the ac source. This power supply consists of a three-phase diode rectifier, a dc chopper and its controller. This controller provides the gate signal of which the duty factor is inversely proportional to the squared rectifier output voltage, the squared dc-chopper input one. The lamps are driven by this dc chopper. The proposed system is very compact and cost-effective compared with the conventional regulated power supply. The experiment shows the usefulness of this method.

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