A development of EV in practical use is studied in many industrial field. The driving system of EV requires compact size, high efficiency and low noise generation. Synchronous motor has many advantages against to induction motor at the point of machine size, weight, power factor and efficiency. However, to get high performance we require position sensor when driving synchronous motor. But, it is better that we reduce position sensor in terms of cost and reliability. So, we reported “Position Sensorless Control of DC Blushless Motor using Current-Source PWM Inverter”.
This system has the characteristics of low switching frequency keeping high performance and low noise generation. But this method estimates the rotor position with the induced electromotive force difference from between modeling and detection. Therefore, in a low speed region, it is difficult to detect voltage precisely.
In this paper, we proposed the improvement of performance characteristics at low speed range. In section 2, we explain the outline of driving system and problems. We show the precise position detecting method with flux estimator in section 3. We presented the experimental result of testing system and that this method is in practical use in section 4. From experimental results, we cleared that this method improve the start, stop and low speed driving characteristics without any additional unit to the previous system.

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We propose CSM (Concurrent Scheduling Method) for the manufacturing site management in the job shop production. CSM aims to complete all the orders keeping the delivery date. In CSM, processing procedure is expressed in the CSM's Process-Chart similar to the PERT chart. The Process-Chart consists of Job-boxes and 2 kinds of Connectors, Connectors-in-the-order and Connectors-in-the-resources. Job-boxes and Connectors-in-the-order show a procedures of an order. Job-boxes and Connectors-in-the-resources show load orders of a resource. Using the Process-Charts, we can see huge information, changing hour by hour. A plan is made reflecting these information, and this plan achieves the flow of the best processing on the manufacturing site.

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This paper presents structural design measures to suppress fluid noises of large capacity open motors at their generation stages without any silencers. Interaction noise, which has high peaks at certain frequencies, is largely reduced by as much as 5dB (A) in the overall noise level by nonuniform distribution of the rotor radial vent openings along the rotor circumference. Turbulent noise, which appears in a wide frequency range, is significantly lowered by as much as 6dB (A) in the overall noise level by unaligning the rotor radial ducts with respect to the stator radial ducts by a vent width. These two structural design contribute to reduce the size of large capacity open motors as small as 1/3 compared to the conventional motors.

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In this paper, we describe the development of AC railway traction current return arrangement for Hokuriku Shinkansen automatic train control (ATC) system. The purpose here is to reduce induced current effects on a linking section in which the two different frequencies (50/60Hz) of the AC electric supply systems meet.
The Shinkansen ATC system, which is required principally as a safety feature to prevent trains from exceeding speed restrictions or passing signals at danger, makes use of the running rails as the transmission medium. In the system, audio frequency track circuits adopting a single side band (SSB) modulation are used both to detect trains and to transmit maximum permitted speed information.
In the Shinkansen SSB modulation, the carrier frequencies are generated by the power sources and synchronized with them. Therefore, this ATC system suffers electrical interference from high harmonic voltage that is synchronized with the different power sources.
To be immune to this interference, we developed an arrangement dealing with traction return current and a composition of track circuits as a result of simulations and practical measurements.

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This paper describes considerations on a Voltage Source Inverter based Reactive Power Compensator, especially load balancing control by symmetrical coordinates frame. Analytical expressions are derived to design the current controllers. With the designed controllers, fast response to the step changes in the reference current values can be obtained. This results in the improvement of the overall system performance. The improved current tracking capabilities of the inner controllers and better performance characteristics of dc voltage and reactive power loops are demonstrated for steady state and transient conditions. Besides this, the required additional loops for load balancing property of the VSI based SVC are investigated by using the positive - negative sequence decomposition calculated in α - β reference frame which gives a faster response than the separation in d-q frame. Simulation results have shown that with the use of simple additional loops, VSI type SVC can also achieve load balancing besides VAR compensation and dc voltage regulation.

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Recently, travel time information is very important at a traffic control system. At present, travel time information is calculated by sensor data such as traffic counter data. However, this method can not apply to a road without sensors. Therefore, this paper verify a travel time estimation method using data obtained from the toll collection system by using actual data. This method mainly consists of a removing method of unusual data, such as extremely long travel time and so on, and a calculating method of a travel time estimation value. A travel time estimation value can be calculated by using this method in the low cost in the road without a sensor. Furthermore, this method was verified by using actual data obtained from an expressway. As a result, the travel time estimation value obtained from the toll collection system confirmed that it was the level which could be used as an actual results value.

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In the soldering process of the printed circuit board, the regulation of the environmental protection will impose the use of the solder alloys without the lead. The basic characteristics of 5 kinds of representative lead free solders were evaluated. Then, new linear electromagnetic pump (abbreviated LEP) which adapted to these lead free solders has been developed. Following items were confirmed by this research.
(1) These lead free solders generate over 10_??_20% large thrust in comparison with the tin lead eutectic solder. Then, it is sufficiently usable as substitute material for the tin lead eutectic solder.
(2) Normalized thrust corrected by the conductivity agreed in the error within ±6%. Therefore, the thrust increased in proportion to the conductivity. The conductivity of these lead free solders is about 10_??_30% bigger than the tin lead eutectic solder.
(3) The maximum temperature of electric wire of the new LEP was lowered 30 degrees in comparison with the conventional LEP in the continuous running. This result shows that cooling characteristics of the new LEP have been excellent.

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This paper presents a method to determine the equivalent circuit constants which accord with the physical construction of synchronous machines, using the D. C. decay testing method with the rotor in arbitrary position (proposed by the authors and called the Expended Dalton-Cameron method).
The conventional Dalton-Cameron method calculates the direct and quadrature axis subtransient reactance from a standstill response test in any arbitrary rotor position using a single-phase power supply. The expended Dalton-Cameron method determines the direct and quadrature axis operational impedances for each slip from a standstill response test using a smallcapacity D. C. power supply.
The direct and quadrature axis operational impedance loci thus obtained synchronous machine constants (subtransient, transient and synchronous reactances) are used to estimate the direct and quadrature axis equivalent circuit constants which accord with the physical construction of synchronous machines.
As an example, equivalent circuit constants are determined for a 10kW laminated salient-pole type synchronous machine with damper winding. The validity of the equivalent circuit constants is confirmed by comparing the calculated resistance and leakage reactance of the field winding determined from the operational impedance when the terminals are short-circuited, to those when the terminals are connected to an external resistance.

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We present a new circuit for resonant dc-dc converter of forward type made of a small number of components which is almost the same in a fly back converter as a smoothing inductor and a free-wheel diode are removed. As parasitic elements like stray capacitors and inductors are operating as a part of a resonant circuit, high frequency switching of low losses can be obtained. A leakage inductance of the transformer is utilized as a inductor of resonant circuit although it prevents the output power going through the transformer in conventional converters.

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This paper focuses on a maximum power point tracking method of photovoltaics by means of use of the short-current pulse. It has been reported that the optimum operating current is proportional to the short current and the maximum power point tracking can be performed by detecting the short current. The proposed method utilizes the intermittent short-current pulse to estimate the optimum operating current and its operating characteristics have experimentally been verified. Also, an adaptive mechanism to identify the parameter between the optimum current and the short current is discussed. A prototype of the controller has been set up and the experimental results have demonstrated excellent performance, which proves feasibility of the system.

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In order to obtain higher efficiency of the micro switching dc-dc converter using thin film magnetic device, FeCoBN magnetic film for thin film inductor was newly developed, which had high saturation magnetization of about 1.7T, and high electrical resistivity over 3μ Ω•m. Consequently, a newly fabricated magnetic thin film inductor using the FeCoBN magnetic film had lower power loss due to the small eddy current loss. 5MHz switching buck and boost converters using the new thin film inductor had higher efficiencies than those of the conventional micro switching dc-dc converters.

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Electric railway vehicles have come to use regenerative brake for normal operation from the top speed to almost zero speed. In the regenerative brake, the terminal voltage of traction motor cannot be increased due to the limited catenary voltage and blocking voltage of semiconductor devices. Therefore, the electrical brake force in the high-speed is smaller than that for middle or low speed. The total brake force for high-speed range mainly depends on the mechanical brake.
By inserting resisters between the inverter and traction motor, the regenerative brake force can be increased in the high-speed range without increase of the rated power or current of inverter.
In light-density line sections, regenerative brake force is frequently inactivated under light-load condition. In this condition, rheostats consume part of regenerative power generated by traction motors when the electric vehicle is braking. Then, the peak regenerative power for the feeder line will be decreased and electrical brake is easily activated, which is another merit.
We studied the possibility to increase the regenerative brake force in the high-speed range by considering characteristic curves, RMS current, and regeneration rates.

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For the purpose of advancing Intelligent Transportation Systems (ITS), sensors capable of gathering precise and various traffic informations are needed. This paper describes a spatial image processing traffic flow sensor we have developed, which can measure wide range traffic flow informations, that is, volume, speed, vehicle type, vehicle presence and traffic congestion length simultaneously as well as detecting illegally parked vehicles and traffic abnormal conditions.
This sensor compresses images inputted from a camera as a JPEG format and then transmits to a traffic control center, where latest images or stored time-serial images before and after an incident detected by this sensor can be seen.
Recently, we have applied this sensor to both a traffic signal control and an image surveillance system, in which an ultrasonic vehicle detector is beneath its capabilities. And we have also constructed a collision avoidance warning system in a tunnel by providing directly most useful queue length measurement results to a variable message board.

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Accurate loss analysis of switch mode circuits that use IGBTs as a switching device is difficult. Switching losses are a function of switch current, collector voltage and junction temperature. These three-dimensional parameters increase equation complexity and are often time consuming in their determination. However, computer programs such as Mathcad^TM Matlab^TM Excel^TM and Table Curve^TM provide practical means of curve fitting empirical data. This paper outlines a methodology for recording and converting empirical IGBT performance data into accurate and useful equations. These equations may then be utilized as simple function calls for loss analysis calculations. The examples covered in this paper are the IGBT clamped inductive turn-off energy and V_CE(SAT) on-state drop. The losses predicted by the empirical equations are compared with in-circuit measured losses. IGBTs representing two different technologies are modeled.

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This paper describes a high-density motor drive system in which the power transmission lines are formed by a multi-layer printed board, making it possible to reduce inductance of lines. The structure of the power transmission lines between the converter and the inverter is determined, based on calculations of the magnetic field distribution generated by the differential (normal) mode current, which leads to an increase in radiated emissions due to the common mode current. The printed power circuit is experimentally verified as an effective way to reduce the electric field intensity from the radiation.

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The immittance converter has an inputt impedance that is proportional to the admittance of a load connected across output terminals. Therefore. in this converter. the output current is proportional to the input voltage and the input current is proportional to the output voltage. Consequently. it converts a constant voltage source into a constant current source and a constant current source into a constant voltage source.
It is well known that the quarter-wavelength transmission line shows immittance conversion characteristics. However. it has very long line length for the switching frequency of converters and is not suitable for power electronics application. So we proposed five types of immittance converters that consist of lumped elements L. C and showed improved immittance conversion characteristics at a resonant frequency.
The output characteristics and efficiency characteristics of an immittance converter is the most important parameter when it is used in practical applications in a high frequency link. In this paper we show voltage-current transformation characteristics. current-voltage transformation characteristics and efficiency characteristics of a Hybrid type immittance converter which consist of L. C elements with losses. The excellent characteristics were confirmed analytically and experimentally.

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For the purpose of improving product design quality, we have developed a system that supports to manage effectively trouble information with a browser based fault tree diagram editor. We also developed another system that systematizes empirical design knowledge and design know-how's as a set of design rules. This expert system generates design review items that are necessary and suitable to be applied to the product designs of interest. These two systems share a function that translates trouble information into design review items, so that the re-occurrence of similar troubles can be avoided.
This paper presents the concept, the implementation, and the benefits of the systems. The evaluation is based on an actual use in the design and quality assurance activities of large scale DC and Induction motors.

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The objective of this paper is to find out arranngements of stator teeth for minimizing the cogging torque and the linkage flux distortion in hybrid stepping motors. First, I clarify the influence of the teeth arrangement on the cogging torque on the basis of the equivalent magnetic circuit of the hybrid stepping motors and propose a new method for reducing the cogging torque. Then the same method is applied to reduce the distortion of coil linkage flux. Last, I verify the result of the above method on FEM simulation of the hybrid steppinng motors using two-dimensional model.
The crucial points of the result are shown as follows: (1) Cogging torque is able to be reduced by balancing permeance vectors of the teeth divided to 2 or 3 sets on the 4th harmonic plane. (2) The distortion of coil linkage flux is also able to be improved by using the similar method on the 3rd harmonic plane.

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Recently the rare-earth magnets NdFeB and SmCo are applied to a magnet rotor of PM motor. The conductivity of rare-earth magnet is higher compared with that of ferrite magnet. The loss due to eddy currents produced in the PM cannot be neglected, especially in high-speed applications, such as electric vehicles. In general NdFeB is coated with Ni and so on in order to prevent from corrosion. But eddy current analysis including coating of PM has not been presented. This paper presents the finite element analysis of eddy currents in coated PM of surface-mounted-PM SM.

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For a two-dimensional drive without detent force and iron loss, we propose the “X-Y linear synchronous motor”. As the stator, the single-layer three-phase armature windings are used without an iron core. Two groups of windings perpendicularly intersecting each other are used for x and y directional drive respectively. As the mover, the field poles by rare earth type permanent magnets are used at both sides of the armature windings. The three-dimensional numerical analysis proves a sufficiently large flux density in the air gap and the smooth thrust without ripple for any directional movement.

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In this paper a dynamic circuit system model of active three-phase current-source PWM converter for Power Factor Correction is described on the basis of instantaneous space vectors. The formulation of the discretized value system and control algorithm to achieve the deadbeat responses of state variables in the utility AC side low pass filter of this converter are evaluated and discussed from an experimental point of view. The system response is much faster and transient oscillations of both source current and capacitor voltage are suppressed effectively, though the state variable in the state feedback is only the current.

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