Abstract-Recently a computer makes remarkable growth. Therefore we become able to analyze a magnetic field using the finite element method. When we design a motor, we have to design effectively and rationally. It is important that understanding ‘design space’. ‘Design space’ means the limit of the thrust or ‘design variables’ within constraints. Within the units limited dimension, we design a Linear DC Motor (LDM) for a pen recorder. This LDM is very thin with long strokes. We describe as follows: (1) We selected the thickness of the permanent magnet and the length of the gap as the design variables in the magnetic circuit of the LDM, (2) We computed the effective magnetic flux density of LDMs using the 3 D finite element method, (3) We made it clear that the design space of thin LDM with long strokes. We suggested the LDM design method. We made the improved LDM. Its measurement value (thrust constant) increased at 0.60 N/A from the first LDM.

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Phase control of capacitor currents is obtained by the method of forced turn-off of the switching devices and turn-on at the phases when the potential differences between AC source voltage and residual voltage of capacitor become zero.
For the technique of forced turn-off of the switching devices which conduct the capacitor currents, two circuit methods have been reported. One of the method used back-to-back thyristor choppers, and the another used coupling reactor. But the former generates pulse noises and the latter operates unstably. Therefore, simple and stable circuit method, without generations of pulse noises, are expected for practical uses. For this purpose, new circuit methods are designed using self-turn-off devices.
This paper reports about the new method and characteristics of phase controls of capacitor currents when self-turn-off devices are used as the switching devices.

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This paper describes thermal modeling for three temperature rise parts of capacitor discharge impulse magnetizer. As the detailed thermal characteristics of capacitor discharge impulse magnetizer can be obtained, the efficient design of magnetizer which produce desired magnet will be possible using our thermal modeling. The thermal modeling method of magnetizing fixture resistor uses multi-lumped model with equivalent thermal resistance and thermal capacitance. Also, the thermal modeling method of semiconductor devices, i.e., discharging thyristor and recovery diode, uses the analog behavioral SPICE model. The reliable results are obtained by using iron core fixture (stator magnet of car air-cleaner DC motor) coupled to a small-voltage magnetizer (charging voltage: 1200 [V], capacitor bank: 4000[μF]).

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In the previous papers⁽⁴⁾, we proposed new control strategies for the matrix converter that is very simple in structure and controllable. By the new control strategies, it is possible to generate the output voltage of 0.866 times the supply voltage and to eliminate voltage and current spikes which are inevitable in conventional switching operations. The experimental results of the matrix converter controlled by the new methods were showed in the previous papers⁽⁶⁾. In this paper, we show the simulated results. It can be concluded that the new control scheme using the intermediate supply voltage can greatly improve the distortion factor of input current from the simulated and experimental results. Moreover, we present the distortion factor of the new converter in relation to parameters of the filter.

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This paper presents a new PWM scheme for NPC inverters which is suitable for large capacity GTO inverters. In conventional NPC inverters, a pulse with narrow width is needed to output low voltage. A pulse width limitation due to the use of GTOs causes a difference between output waveforms and reference voltages. In the proposed scheme, square wave is added to all the three phase voltage references, and low voltage, therefore, can be developed without using the narrow pulses and waveform distortion is significantly reduced. Two triangle waveforms, one is for positive and the other for negative, are shifted by 180 degrees with respect to each other. The shift holds the switching frequency even with the addition of the square wave. A new neutral point voltage control is proposed along with the proposed scheme. This paper provides theoretical analysis and experimental results for the proposed scheme.

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Recent increase of semiconductor power converter systems brings about harmonic problems. In a single phase power converter, a capacitor-filtered rectifier is used to derive DC voltage from an AC commercial power source. This converter generates harmonic currents and its power factor is very low. In order to reduce harmonic currents and compensate the input power factor, we propose a novel switching method, called the simple partial switching method (SPSM), for a single phase AC to DC converter. A control device of the converter switches once in every half cycle of an AC commercial power source by this SPSM. The switching timing is decided by the input power factor and by the odd order harmonic estimation function of the input current. The estimation function is defined as the harmonics ratio compared with the harmonic currents standard. Experimental results clarify that our SPSM converter reduces harmonic currents and compensates the input power factor.

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Hydrogen is regarded as a potential future energy carrier. It is produced by water electrolysis. The power required is supplied by photovoltaic array. The hydrogen has been produced by using the hydrogen generator typed solid polymer electrolyte with photovoltaic module rated 2.4V, 32A. We have designed and constructed the experimental system that photovoltaic module coupled with hydrogen generator directly, and measured and analyzed the basic characteristics, i.e. production of hydrogen, I-V characteristics and cell temperature for photovoltaic module and hydrogen generator. It was found that the variation of cell temperature and irradiance influenced on production of hydrogen. Then the optimum design method of solar hydrogen energy system has been developed from the hydrogen production cost point of view. In this method, the design point is decided by the irradiance intensity when the system is operating under rating capacities. As a result from the basic data of experimental system, the optimum design point of solar hydrogen energy system depends on the ratio of photovoltaic array cost to hydrogen generator cost in system.

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Genetic Algorithms (GAs) are powerful and usable algorithms for the nonlinear optimization problem, and some studies of application of GA to the control problem were reported. The search process of GA depends on the fitness value which is assigned to each candidate solution by the fitness function. But as the control objective is more complicated, the design of the proper fitness function becomes more difficult.
In this paper, we propose a new search method of GA which reduces the difficulties of the design of the fitness function. In our method, the control objective is divided into some intermediate objectives according to the control strategy, and the search process of GA proceeds with the fitness function for the intermediate objective. The search process is controlled by switching the fitness function based on the average fitness value of the current candidate solutions so that the optimum solution is found. Thus, the search space is structured by using the fitness function and the structure is changed by switching the fitness function based on the quality of the current candidate solutions. In order to confirm the availability of the proposed method, the swing-up control problem of a pendulum is used as an application example and the simulation results are given.

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The 2-mass system is the simplest model which generates a torsional vibration. In this system, two simple controllers are effective in suppressing the vibration. One is resonance ratio controller, and the other is PI controller with the first order lag filter.
This paper studies the 2-mass system controlled by a state feedback controller and clarifies that PID controller is able to determine the damping characteristics of the closed loop system in spite of its speed of response. In addition a new method to adjust PID controller is developed. Finally the above-stated two controllers are clarified to be the variations of PID controllers, because these controllers are designed only by adjusting parameters which determine the damping characteristics with the method.

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This paper describes a knowledge acquisition method based on data and domain scientific knowledge and its application to a sintering process in an iron and steel making plant. Our interest is focussed on the extraction of operational knowledge to meet the given quality specification while reducing the cost. Our approach consists of the following two stages: First, using a three-layered neural network (NN) and our newly proposed algorithm, we extract candidate operational rules which describe the chemical composition of the materials and the operational condition. Among them, we select the rules which are valid viewing from the domain scientific knowledge (i. e material science) as well as effective in reducing the cost of production. Our method improves the efficieny in accumulating the operational knowledge which is crucial for stable and effective production, but, traditionally, requires considerable time and efforts.

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A study on highly efficient excitation system would to be important to enhance the potential of superconducting AC generators hereafter. Based on such a thought, we have fabricated a new conceptual machine for actually generating electricity with a brushless exciter system using a superconducting dynamo i. e. “Magnetic flux pump”. Moreover, a fully superconducting generator with both of superconducting armature and fileld windings has been studied for the past seven years.
The paper describes the experimental model machine and the test results on characteristics of brushless excitation using the magnetic flux pump when the machine operated as a fully superconducting brushless generator of an estimated capacity of about 20 kVA.

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This paper presents a new floor-heating system for an electric train using sheathed heaters laid under the floor. The system has special heat reflective plates of aluminium with small emissivity and the lower surface of the floor being coated with a fireproof paint with large emissivity surrounding the heaters. The plates decrease heat loss radiating from the floor and the coated surface absorbs more heat from the heaters. The efficiency of the floor-heating is raised.
Authors make an experiment by a simple test model of floor-heating of the electric train, propose a two-dimensional thermal calculation model using a finite element method to analyse the process of heating of the test model and ascertain that the model enables the heating process to be analysed with a high degree of accuracy according to estimations made for the test model.
They calculate the temperature rise of its sheathed heaters, reflective plates and floor via the above model regarding the emissivity of the heater surface as a parameter for both cases of the surface being coated and not coated and estimate quantitatively that the floor-heating system is very effective. In the case of the lower surface being coated, the heater temperature is about half as high as that of it being uncoated and the radiant heat-exchange factor between the heater and the lower surface is about 3.4 times as large as that of in the case of it being uncoated with the emissivity being 0.1, and about 3.7 times as large as that of it being uncoated with the emissivity being 0.45.

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Recently in the conurbation area, traffic congestion on railway system is very terrific and the commutation area have been spread out year after year. So it is required to reduce traffic congestion and to shorten time to arrive at the destinations. Recent development of information system in a railway system makes it possible to know more accurate passengers demand in real time. In this paper, we propose a method to make more flexible train schedule based on passengers demand. The proposed method can make a train schedule to satisfy the most amount of demand and make the total trip time of passengers smallest. By setting number of trains and their start times, stop patterns of trains are automatically generated and evaluated by train traffic simulations and passengers flow simulations. These simulations are executed repeatedly to evaluate trial schedules in the planning process and so efficient simulation methods are also proposed. The effectiveness of the proposed method is examined through some examples of applications based on practical railway models.

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A magnetically levitated (MAGLEV) vehicle propelled by a linear synchronous motor (LSM) is one of hopeful candidates to be used for high speed transportation in the next generation. The vehicle will be automatically controlled from start to stop by a control center. In order to increase the ride quality of the vehicle, feed-forward control of the running resistance is added to an ordinary feed-back speed control to compensate disturbances due to fluctuation in a running resistance.
The running resistance is also required to predict a current reference to the next substation which covers a section into which the train travels. The running resistance of the MAGLEV vehicle is modeled as a function of speed and is used for feed-forward control and calculation of the estimated current in the substations. The modeling requires identification of the coefficients of the function to specify the running resistance.
The formulation of these coefficients has been studied in theory in other literature. No effort, however, has been reported on their quantitative estimation with the use of experimentally gathered running data. This paper proposes a method for identifying these coefficients by successive learning. In this process, these coefficients are modified by means of the method of steepest decent to minimize the error between measurement and estimation of the function. Systematic learning can therefore be realized.
Its usability is confirmed with the data gathered at the MIYAZAKI test track.

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It is important item for maintenance of overhead contact line to manage the state of contact wire wear exactly in electric railways. There is a measuring apparatus using in daytime, but it is so large that it should be installed in a exclusive car. So that, a new type of measuring apparatus has been developed, which is so small as to be installed on the roof of a commercial car. The apparatus has an optical system composed of sodium vapor lamps and CCD linear sensor cameras with optical filters. The new apparatus has been tested in laboratory and in field using a test car. The results show that it can be used at 100km/h speed in daytime, and standard deviation of measuring error is 0.3mm.

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For Projected Shinkansen, it is necessary to develop an economical overhead catenary system allowing stable train operation at high-speed and meeting the transport demands. In order to develop a new overhead catenary system for this purpose, we designed a high tension simple catenary system with CS contact wire (Copper contact wire with Steel-core), and constructed this system on Tohoku Shinkansen line for operation test. During 4 years, we measured contact loss of pantograph, uplift and stress of contact wire, its maintainability including the wear of contact wire, and others. The test results so far obtained prove that its performance is as high as that of high-tension heavy compound catenary system.

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A long-pulse TE-CO₂ laser without spike-output has been developed. It has produced 2J in a long pulse. The optical pulse length is extended to 10μ sec by using a pulse-forming network. And the optical waveform is controled by an injection method. As a result, the spike-output of TE-CO₂ laser is completely disappeared by injecting CW-CO₂ laser which provides 150mW.

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