The contour control for industrial mechatronic servo system such as cutting process, sealing and boundering is required. A method of contour control for mechatronics servo system was investigated by improving synchronous position control. The proposed method was analysed theoreticaly and evaluated by an experiment with two AC servo motors under torque disturbances. The both results of a computer simulation (analytical one) and the experiment showed satisfactory contour control performances for various conditions.

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The effective usage of the power facilities can be realized by leveling the fluctuating active power and compensating the reactive power. The fuzzy and fuzzy-neural network control strategy of superconducting magnet energy storages (SMES) was proposed for this purpose. The control results depend on the values of coefficients of learning rate in fuzzy-neural network. Therefore, it is desired to obtain better control results that the coefficients of learning rate are tuned to the optimum value.
In this paper, the control strategy based on an auto-tuning of scaling factors with neural network and tuning of coefficients of learning rate of neural network with genetic algorithm is proposed for leveling load fluctuation. Encoding and decoding of coefficients of learning rate and selection, crossover and mutation of genetic operation are shown and crossover rate, mutation rate is discussed. Then, we can achieve the better leveling of load power fluctuation by using fuzzy-neural network with genetic algorithm.

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In industrial plants such as those for iron and steel process, paper machine process and others, multimotor drive system are very popular. Speed sensorless vector control is most suitable for those system with high performance, high reliability, low cost and less maintenance. Very few papers about multimotor drive system, however, have been reported. This paper describes such a drive system.
In case of unbalanced load among the motors, the phase differences between their vectors cause insufficient performance, especially during regenerating at low speed. In this paper, we propose an advanced sensorless control for multimotor drives. The proposed control system estimates the axis of the motors with heavy load and follows it.
The proposed drive system are now operating with good performance in steel and other plants.

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This paper proposes an “active common-mode noise canceler” that is capable of eliminating the common-mode voltage produced by a voltage-source PWM inverter. It generates a compensating voltage which has the same amplitude as, but the opposite phase to, the common-mode voltage produced by the PWM inverter. The compensating voltage is superimposed on the inverter output by a common-mode transformer. As a result, the common-mode voltage applied to the load is canceled completely. The design method of the active common-mode noise canceler is also presented in detail.
A prototype has been constructed and tested to verify the effectiveness for an induction motor drive system of 3.7 kW using an IGBT inverter. Some experimental results show that the proposed active common-mode noise canceler makes a significant contribution to eliminating the common-mode current or the ground current, and it prevents an electric shock from being received by anyone who is touching.

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In order to get a high performance and a high accuracy for servo system in several industrial applications, a servo motor system requires a realization of robust control for wide speed range. The conventional robust control system based on disturbance observer can easily design a reference response and a disturbance rejection response, but it often does not consider a robust stable condition. In order to overcome this problem, this paper proposes a new two-degrees-of-freedom control system based on disturbance observer and coprime factorization. The proposed two-degrees-of-freedom control system considers a robust stable condition and a disturbance rejection response systematically. If the frequency band of disturbance rejection is narrow, the proposed system satisfies the robust stability condition
In this paper, the robust speed servo system of DC servo motor is constructed by the proposed two-degrees-of-freedom control system. The experimental results show that the proposed speed servo system well regulates a motor speed robustly for wide speed range, in comparison with the conventional robust speed servo systems.

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In this paper, the control system which has been proposed to upgrade the toroidal field coil (TFC) power source at JFT-2M tokamak machine in Japan Atomic Energy Reseach Institute is presented. This power source, us-ing four dc generator-motors with flywheel (DCG) for storing 210MJ of the energy, can produce 51.3MW (2.7kV, 19kA) of the flat top over 1 sec. The control characteristics of the DCG operating as generator are described, especially emphasized such features as the unique method for opening the contactor of a main-circuit-switch by controlling the field current of DCG. A pair of thyristor convertors for DCG exiciter are used not only for rapidly varing the coil current between zero and 19kA, which are original purposes, but also for reducing it to less 10A to make the contactor of the gaseos circuit braker (GCB) for the switch open. The system configuration and the operating principle of the proposed control system are explained, and the basic characteristics which have been investigated by solving directly the linearized equations for the system or the analog simulation for it are presented. The required performance has been achieved through the field-tests, and some of test results were compared and got good agreement with the simulation results.

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This paper presents an improvement circuit of the high power-factor of AC-DC converter by employing a half-bridge system that enables a soft-switching in step-up converter.
In this circuit the improvement of power-factor will be facilitated, under critical conduction mode, with the half-bridge type converter, and such power-factor improvement can be achieved without using multiplier, and larger voltage than the peak value of stepped up AC voltage will be charged in an electrolytic capacitor. Analysis of the performance of circuit proposed was carried out, and a converter having 97% high power-factor could be developed by identifying the relation of parameter of step-up factor (alpha) and selecting the reactor appropriately. We also have introduced, as one of the applications, a low cost one-converter that making the main switch part common by connecting the half-bridge type converter to the post-stage

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This paper proposes a simple and effective method for improving the power factor of a capacitor-filtered single phase rectifier circuit. The fundamental idea is to use an ac nonlinear reactor and to insert it to the input side of that. This reactor has two values of inductance. For the current less than a previously specified value, the inductance is low, whereas it is high when the current is larger than that. Such a reactor can prevent the current from excessively rising when it is in an increasing state. This leads to a great suppression of the higher harmonic currents and to an improvement of the power factor. The effectiveness of the proposed method is confirmed through the experimental test and the computer simulation.

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The authors have been considering to use a linear pulse motor (LPM) as a driving source of a totally implantable artificial heart (TAH), and have developed a series of artificial heart models that incorporate such a motor. The newly developed linear-type TAH (linear TAH) has two blood pumps, which are inflated and deflated alternately by the LPM, causing a pusher plate to pulsate the blood.
This paper deals with the performance calculation of the LPM using the loading ratio. Then some motors manufactured for driving TAHs were selected to compare their machine parameters. The selected motors were LPMs, linear oscillatory actuator, brushless dc motors, and ultrasonic motor. Two parameters were selected for the comparison: the mechanical output/volume ratio and the motor constant. The results may be summarized as follows:
1. the LPM was designed based on the loading ratio, and the kinetic thrust and velocity were obtained at the range of 77 newtons, 80mm/s respectively;
2. the loading ratio of the LPMs were more than eight times larger in comparison with the rotary motors which were used in industrial machines;
3. the motor constants of the LPMs were recognized one figure larger than that of the bnrshless dc motors.
In order to reduce the volume of the linear TAN, it is necessary to increase the drive velocity of the LPMs. Application of the linear motor to a nonpulsatile artificial heart will be one way to achieve this.

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In Japan speed tests in 300km/h region have been carried out since Oyama Test Line recorded a 319km/h run in 1979. Meanwhile TGV recorded a 515.3km/h run by an electric locomotive installed with a pantograph in 1990 and ICE did 406.9km/h using similar train in 1988. High speed current collection tests over 400km/h using electric railcars have been desired in Japan. Problems of high speed tests are: train speed approaching wave propagation velocity, multi-pantographs resonance, and too large uplift of contact wires caused by lift. It is necessary to keep wave propagation velocity of contact wire higher than train speed. CS contact wire and TA contact wire were compared in high speed tests because it was impossible to get a good current collecting performance by using hard-drawn copper contact wires. In December, 1993 using these contact wires we carried out high speed running tests of 400km/h region on Jyoetsu Shinkansen with the test train STAR 21 which JR EAST built for high speed tests. This paper gives the current collecting performance of these contact wires predicted by simulation and running tests at 425km/h.

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In the linear induction motor, the original equations of the secondary equivalent circuit quantities derived from the two-dimensional electromagnetic analysis was expressed in combination with hyperbolic function and trigonometric function of complex number.
In this paper, it has been successfully investigated to deduce the equations for calculation of the secondary resistance and the secondary leakage reactance referred to the primary.
These equations are approximated by the Maclaurin's expansion and are expressed by polynomial approximation. This paper also shows the variation of those equivalent circuit parameters with slip and the change of the operating characteristics with various thickness of the secondary conducting plates.

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This paper describes the equations for calculation of the equivalent secondary resistance and the equivalent secondary reactance referred to the primary of single-sided linear induction motor (SLIM) and shows the change of those equivalent circuit parameters and the operating characteristics with various secondary conducting plates.
Usually, a composite conductor slab which is consisted of an aluminum plate backed with a solid steel plate is used. In order to simplify the calculation, we have assumed that the back-iron plate consists of a laminated core instead of a solid steel core.
Firstly, the computed results of the performance characteristics of a SLIM with the secondary aluminum plate backed with either solid steel plate or laminated core are shown comparatively.
It was confirmed that the characteristics curves in the case of laminated core give close agreement with the curves in the case of solid steel:
In practice the reaction rail backed with a solid steel is better than that backed with a laminated core from the point of view of economy, robustness and corrosion.
Next, the calculated results of the performance characteristics of a SLIM with a single secondary aluminum plate or a single secondary iron plate are shown.

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We propose a method of a single phase PWM for an independent power supply in photovoltaic power generation systems. This new PWM is derived from comparing levels of signal waves with ones of carrier waves which have bipolar swing different from unipolar one in the conventional PWM. In this PWM, We can use a battery with lower voltage in combination with the photovoltaic power generation; fundamental level of output voltage is raised by about 11%, though poor in quality of waveforms.

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Recently, a neutral point-clamped type inverter (three-level inverter) with large capacity has come to be used in a train, etc. for driving A. C. motor. The three-level inverter has an advantage of being low in harmonics unlike conventional two-level inverter. Moreover, if DC-voltage is at same voltage, a transistor or an IGBT whose switching frequency is high can be used as a substitute for high-voltage GTO thyristor, because the number of switching elements in one arm is double.
However, the three-level inverter has a drawback in that the output voltage is not controllable smoothly in the case of output voltage being low. It is because the switching element needs a minimum on-off time; this is especially remarkable with the GTO thyristor whose minimum on-off time is long. In order to avoid operation with this drawback, the three-level inverter frequently adopts a dipola modulation. The dipola modulation adds a bias component to the control signal of output voltage lest the control signal should become low-level, and it generates simultaneously a pulse voltage to cancel the bias component.
In this paper, first, the output voltage of a three-level inverter with single phase using dipola modulation is analyzed, then its characteristics of harmonics are made clear. Second, in the case of a three-level inverter with three phases, zero-phase sequence component of harmonics are described. Third, characteristics of harmonics are analyzed in the case of three-level inverter being multiply. Lastly, what are described above are verified by simulation.

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A new digital redesign method is proposed for both a continuous time state feedback controller and a dynamic controller. In the proposed method, the N-Delay control is employed, and the lth plant inputs are changed N_l times during one sampling period. The goal of this paper is to develop a new digital controller from the analog controller so that the states of the digitally controlled closed-loop system completely match those of the original continuous time controlled closed-loop system at every sampling period. An illustrative example of position control using DC servo motor is presented.

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