The advantages of current fed type PWM inverter system over voltage fed type PWM inverter system are regenerative capability with a single converter and the realization of sinusoidal voltages and currents by lower switching frequency. This paper proposes a new sinusoidal voltage supply using the current fed type inverter based on the instantaneous voltage vector control. In this system, the output voltages can be obtained directly by the feedback control of the instantaneous vector. So, the proposed inveter system has the simple control circuit, the fast response, and the robustness for disturbance. In addition to these, it is possible that the pure sinusoidal waveforms of load currents are achieved by reducing the ripple of the output voltages under the inductive load. This paper presents the PWM controll method by the feedback control of the output voltage vector. Moreover, the feasibility of proposed voltage supply is confirmed by some simulations and experimental results using a small test system.

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The paper presents the low power inverter controlled wound rotor induction motor-based compensation scheme for impediment current in the power distribution system. The impediment current means the harmonic current, reactive current, unbalanced current and the peak active current. One of the cost-effective and reliable solutions for compensation is the wound rotor induction motor with a flywheel when the rotor is excited by the low power inverter/converter system. From the economical standpoint, the motor speed should be controlled in the vicinity of the synchronous speed when the peak load current is compensated for by the kinetic energy of the flyweel. This kind of load leveling should be performed under the restriction of limited power capacity of the inverter.
The authors propose the optimum design rules of the control loops to satisfy the load leveling specifications. The effectiveness of the proposed approaches have been verified by experiments.

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When two power supplies with near-by frequencies are connected to a 2-phase induction motor, the motor generates the two kinds of oscillatory torque components, which have frequency components of the summation and the difference between the frequencies of the power supplies. These oscillatory torque components are sinusoidal and the torque with the frequency component of the difference is considerably larger than the torque with the frequency component of the summation. Consequently, the motor behaves as a swing motor, which alternately changes the direction of rotation.
Because of the regularity on the period of blood beat in human body, this swing motor is suitable for the driver of an artificial heart. We propose here to use this swing motor as the pump for the artificial heart, which is used to send the blood at an operation of heart.
In this paper, we present the fundamental theory and the characteristics on the swing motor, and the outline of the motor action for the artificial heart.

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This paper proposes a new method for extracting the feature of lip motion. The proposed method was carried out without special conditions such as lipstick or lighting. The method consists of three steps. Four feature points are manually selected on the first frame. They are the upper, lower, left and right points on the outer lip contour. And then, the outer lip contour is approximated to a polygon with each point. Finally, four feature points are traced using optical flow in next frame. The temporal feature of lip motion is extracted by repeating second step and third step.
It is observed that proposed method is able to approximate the outer lip contour to a polygon. The proposed method is also able to trace automatically the feature points in continuous image. The experimental results indicate that the proposed method is the effective technique for extracting the feature of lip motion.

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Extracting rail loci and estimating track shapes from a railway picture are basic problems in applying image processing to railways, such as steering control in accordance with curvature, and guard watch on running ways. We proposed a new operator to extract the loci reflecting the figures of rails according to the position and direction of locus. A trace method is applied to the result of operator processing, in which rail loci are extracted as fractional straight lines using the Hough transformation in each divided zone. Three steps of process are introduced to decide three-dimensional track shapes. In the first step, the direction of the locus is estimated by the restrict conditions of parallel rails. The direction of a cross tie is decided in the second step based on the condition of the given superelevation, and finally the distance between the rail and the camera to take the picture is estimated in the last step from the gauge between the rails in the picture. Applying this method to real images, we have confirmed feasibility of this method.

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Superconducting conductors which are composed of many superconducting strands have a problem of current imbalance. This may cause the conductors to quench at a current level below its design value. This paper proposes the iron core methods to fix the current imbalance problem. The iron core method is the one in which two insulated strands are passed through an iron core with electric currents circulating in opposite directions. We investigated the current imbalance by using Ag sheathed Bi-2223 high temparature superconducting wire. We observed that the current imbalance was corrected by using ferrite iron core in liquid nitrogen. Finally, we discuss the size of iron core needed to solve the current imbalance problem.

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This paper proposes the simplification of the synthesis method of PWM pattern by using the Walsh function. The digital nature of the Walsh function makes the relation between the Walsh spectrum and PWM pattern being a linear algebraic equation. Thus the synthesis becomes straightforward. It is the remarkable feature of the proposed method over a conventional method using Fourier expansion.
In addition, by using Fourier-Walsh transform, an iterative synthesis process can reduce low-order harmonics of the PWM pattern in Fourier spectrum. Several examples confirm the validity of the proposed synthesis method.

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The dead-zone effect for control input of ultrasonic motor arises with applied load torque. The dead-zone is a problem as a accurate positioning actuator for industrial applications and it is important to eliminate the dead-zone in order to improve the control performance. This paper proposes a position control scheme of ultrasonic motors taking dead-zone compensation into account.

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Nowadays it is not enough to supply products based on customer's preference, and both manufacturers and distributors must have excellent order fulfillment. Leading manufactures and distributors are embracing a variety of new logistical techniques and closely managing their suppliers in order to improve the fulfillment. They should work to optimize the flow of goods and services through their organizations, from the delivery of a supplier's source materials to the product's final disposal. In this paper a new concept based on multi-agent paradigm, such as contract-net and market oriented programming, is introduced so as to facilitate appropriate order fulfillment. Simulation results indicate the effectiveness of the proposed algorithm and detect further research subjects.

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The use of PWM-inverter with high switching characteristics to provide the variable frequency supply to motors causes the overvoltage with steep-fronted waveform on the moter terminals.
Insulation failure in motor winding can be caused by this steep-fronted transient voltage in inverter drive system. From the point of view of the wave propagation with skin-effect of the cable conductors, these phenomena are not reported in the papers. The main purpose of this paper is to describe the exact surge propagation into consideration of skin-effect of the cable conductors and the wave deflections at inverter and motor terminals.

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It is important to discuss the behavior of traffic at merging sections in the design of the overall AGV system and in the realization of the system. In this paper, we deal with a merging section of the Automated Guided Vehicle System under time limit for merging. Near the merging section, one flow of traffic must form a queue to avoid collision of vehicles. We have analyzed the vehicle behavior at the merging section of the AGV system using the imbedded Markov chain method. The analytical solutions have been obtained.

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In Japan, the AC single phase electric railway system is adopted on main lines such as Shinkansen. The allowance range of feeding voltage for Shinkansen is 22.5_??_30kV.
In recent years, the service load tends to increase with more frequent train operation, increased speeds and multiplied power. As the load capacity of train becomes larger, the reactive power of load causes a larger voltage drop. It is anticipated that the feeding voltage would drop below the lower limit of the allowance voltage range.
With advance of power electronics technology, voltage drops in a feeding line and voltage fluctuations on the 3-phase side can be reduced, and the power factor at substations can be improved by compensating for the reactive power using a single-phase static var compensator (SVC).
To compensate for voltage drops over AC feeding system, SVC should be located at the end of feeding circuit which is called sectioning posts. The capacity of SVC can be reduced to two-thirds by locating it at sectioning posts instead of substations.
This paper describes the principle of voltage compensation using SVC with TSC installed at the sectioning post in San-yo Shinkansen and introduces the results of a site investigation.

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The authors propose the new brushless DC motor without stator slots as a servo motor. The conventional motor has a lots of stator slots, and the stator coils are placed in the slots. In the new motor, the stator has no slots. Accordingly, the stator coils are fixed along the inside of the stator cores, and the coils are molded by a thermosetting resin. Therefore, the magnetic airgap is very large. Generally, as leakage fluxes increase in response to the size of the airgap, output torque decreases. But the new motor improves characteristics of torque by using a new magnet having high magnetic energy. And the new motor without slot does not produce cogging torque and electromagnetic noise and torque ripples of harmonic magnetic fluxes caused by stator slots. In this paper, calculated characteristics analyzed by flux density using FEM and experimental result is described. It is confirmed that the analyzed results agreed with experimental results with good accuracy. In the experimental results using a 4-pole 0.4kW test motor and high-efficiency drive inverter with power factor control, the motor efficiency is about 83.7%, the motor power factor is about 96.9%, and cogging torque is zero.

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The compact electronic devices such as electric shaver and cordless phone with non-contact charging system have been widely used. A detachable transformer with a magnetic coupling is used in this system The magnetic coupling of the coils over the air gap causes leakage inductance. For this reason, the load matching technology is required to miniaturize the system The parallel capacitor connected to the secondary coil ofthe detachable transformer is very available method for load matching, The optimal value ofthe capacitance is influenced not only by frequency and leakage inductance but also by cell voltage and secondary induced voltage. It has been determined by trial and error after the experimentation or circuit simulation. Through our careful observation of the experiments, we found that a distinct waveform exists when the best value has been chosen for the capacitor with the charging current of the maximum average. This paper shows, far practical calculation purpose, an equation ofthe optimal capacitance and maximum charging current, based on the distinctive waveform in the non-contact charging systemwith half-wave rectifier. Experimental data are given to prove the validity ofthis expression. At the end, some ofthe characteristics are also given to show the capacitance and the average charging current underdifieient circuit conditions.

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In this paper, we propose a vibration suppression method for position control including a speed minor loop designed by pole placement approach. Experimental results show the validity of our proposed.

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This paper proposes a method to damp the harmonic resonance at the dc-link of a large capacity rectifier-inverter system such as in rapid-transit railways. A voltage-source PWM converter is connected in series to the dc capacitor of the rectifier, acting as a damping resistor to the dc capacitor current. No filters axe needed to extract harmonic components from the dc capacitor current. This system is thus highly stable and the required rating of the PWM converter is very small. The basic principle of the proposed method is confirmed using digital computer simulation.

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The authors have proposed the VAPAR (Variable Active-Passive Reactance Circuit) which can generate not only a positive reactance but also a negative reactance applicable to a power circuit. To help understanding of a negative inductance, at first, the difference between a negative inductance and a capacitance is clarified by demonstrating simulations of series LCR and LL_nR(L_n<0) circuits. Then the characteristics of the negative inductance is also exemplified by a dynamic model using a motor-assisted bicycle.

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In one of the methods for reducing of the coulomb friction force, a method for adding a dither to the driving current of the motor is proposed. However, how amplitude and frequency of a dither should be selected, has be not made to be being enough clear. In this paper, a dither is used for the drive of linear DC motor in order to realize smooth start up and stop in the low-speed region. As the result, following matters became clear.
1. The dither frequency is mainly dependent on the electrical time constant of exciting coil.
2. If the dither current equal to 50% of main current is added, 36% of the positioning error can be reduced.

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