This paper provides circuit equations of salient pole synchronous machine and its analytical solutions. The author expressed cross section of synchronous machine as complex plane and named it space complex plane. Voltages, currents and magnetic fluxes expressed in this complex plane, were named space voltages, space currents, and space magnetic fluxes respectively.
To distinguish ordinary complex quantities, such as complex currents of single-phase circuit, from space complex vectors, such as space complex currents, The author named them time complex vectors temporarily in this paper.
Using these space complex vectors and time complex vectors, The author analyzed salient pole synchronous machine.
For instance, calculated results of transient phenomena of 3-phase sudden short circuits of salient pole synchronous machine are showed in this paper.

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An efficient periodic steady-state analysis method of power electronic circuits is proposed. The method finds initial values which satisfy a steady-state boundary condition by solving a sensitivity matrix equation. For this matrix computation process, consideration of switch timing variations is essential especially for closed-loop controlled circuits to improve stability of the algorithm. This paper derives a precise and general computation algorithm of the method, which is validated through examples of converters.

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This paper proposes a new robust speed control system based on disturbance observer and coprime factorization for mechanical systems. The proposed system takes account of large variation of inertia ratio. It has the two loop systems. The inner loop system is the state feedback and the state observer system, which is designed by coprime factorization. In this paper, the poles and parameter variation effect of inner loop system are newly determined by using the polynomial coefficient approach. The outer loop system based on disturbance observer satisfies the robust stability condition on parameter variation. The reference response easily defines the desired transfer function from the speed reference to the load speed. The numerical simulation results show that the proposed system well regulates the load speed and suppresses the torsional vibration phenomena.

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This paper presents new block diagrams for induction and synchronous machines. The proposed block diagrams succeed in realizing simple and clear configurations with physically meaningful signals, which are helpful for understanding machine electromagnetic mechanism and useful for designing controllers for them. Vector signals are utilized as transfer signals between blocks instead of conventional scalar signals. Three configurations for induction motor, two for synchronous motor, one for induction generator, and one for synchronous generator are shown.

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The development of zero-voltage switching (ZVS) technique has attracted for many industrial applications. We had presented a quasi resonant ZVS buck converter linked with a buck-boost component. The output voltage of the ZVS buck-boost component is had to be controlled by the maximum current in the switching devices. However the transfer function with the input which is the maximum current in the switching devices is not proposed.
In this paper, a transfer function at the ZVS buck-boost converter controlled by the maximum current in the switching devices is proposed. The transfer functions are expressed by the differential equation of the storage energy in the resonance reactor resonance capacitor and the smoothing capacitor.
The transfer function is conformed by the computer simulation and the experiment.

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The Fuzzy Multiple Regression Model (FMR Model) is a powerful non-linear identification tool, which has been applied to actual process controls and demonstrated its effectiveness. A major problem, however, is hardness to determine its rules and membership functions properly.
In this paper, we discuss how to optimize the FMR Model automatically with data obtained from an actual plant. First optimization with considering the interaction between membership functions and rules is shown to be essential to obtain the accurate FMR Model. Then the optimization algorithm based on the simulated annealing is proposed, which is performed interactively with the multiple regression analysis for deciding consequent part of rules. How to accelerate the algorithm is also investigated from a viewpoint of the decrease of the number of multiple regression analysis executions. Finally usefulness of the developed method is evaluated with several simulation results, where it is applied to create a coating weight prediction model used in a continuous galvanizing line.

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One of the most emphasized problems to be solved in power systems in recent years is the line-current harmonics problem. This is due to the use of diode rectifiers, PWM converters, nonlinear loads and so on. To reduce or eliminate such current harmonics, an active power filter (APF), which is a sophisticated power electronic converter, has been studied and used in some practical applications.
In this paper, we propose and discuss two new control methods for three-phase shunt APFs: the sinusoidal linecurrent control method and the instantaneous-reactive-power compensation control method. They are based on pulsewidth prediction control, or a predictive-instantaneous-current PWM control. Neither any instantaneous power information nor coordinate transformation is necessary for control. In the sinusoidal line-current control scheme, the controller governs the switching devices of the APF by using the pulsewidth that is optimally predetermined at the beginning of every switching period with the sinusoidal current reference. The line-currents flow sinusoidally and are in phase with the voltage accordingly. In the instantaneous-reactive-power compensation control, the control is performed so that the resultant circuit of the load and the APF is regarded as a time-variant conductance circuit model. The APF with this control scheme can cancel effectively the instantaneous reactive component produced by the load though the controller is simple.
This paper discusses the performance characteristics of the APFs when a three-phase diode rectifier and an unbalanced load are connected to the line. The practicability of the proposed methods is verified by experiment.

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This paper presents a zero-current-switched voltage-fed inverter equipped with resonant circuits on the ac side. The current flowing through a switching device, i.e., an IGBT is a sum of the load current and the resonant current. When the amplitude of the resonant current is larger than that of the load current, the current in the switching device becomes zero at an instant in each resonant cycle. This allows the switching device to be turned on or off at the zero current. The zero-current-switching makes a significant contribution to reduction of switching losses and electromagnetic noises.
In this paper, the principle of zero-current-switching operation, along with a novel control scheme, is described from a theoretical and practical point of view. Experimental results obtained from a laboratory system of 5kVA verify the practicability. Moreover, the switching and conduction losses of the proposed soft-switched inverter are compared with those of a conventional
hard-switched inverter.

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It is well known that high dv/dt rates on the switching devices are the source of EMI noise. This paper describes a mechanism and reduction methods of EMI radiation noise on IGBTs. The radiational noise is generated by oscillating current flowing through the IGBT's output capacity and the snubber circuit, which we call equivalent circuit of radiational noise. The oscillating current of the equivalent circuit is forced to flow by the high dv/dt rates of IGBT switching operation. Radiational noise can be analyzed by frequency evolution of oscillating current. These results of this analysis show the relationship of high frequency impedance of the equivalent circuit to radiational noise, as well as the relationship of IGBT's switching voltage waveform. In addition, it is indicated that using a di/dt control gate drive circuit is effective as a means for reducing radiational noise. It is clarified that the standard for industrial equipment of CISPR can be satisfied by using proposed gate drive circuit. The effect of the method has been verified by expeimental and simulational results.

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Development of a single phase universal electric load having power regeneration ability controlled by real time simulator is described. The developed electric load has following ability.
(1) It can realize small size and light weight, and can be greatly reduced power supply capacity on the various load testing by using computer various load simulator.
(2) It has not only regeneration but also the active filter ability that feeds back the active power to the power supply side for achieving unity power factor on that side and effective power use.
(3) The load simulator can change various loads by the personal computer software.
The load converter is consisted of a full bridge construction controlled by using load current follow-up method. The power regenerative inverter is consisted of the half bridge construction with controllers of dc link constant and unity power factor on the power supply side. The load simulator is consisted of the personal computer.
It is possible to carry out excellent simulation of loads including sharp load fluctuations, rush currents and harmonics.

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EMI in the universal motors remains as a very important problem to be solved and is conventionally evaluated by the remote measurement of noise figure at the distant point from the noise source.
In order to clear the mechanism of noise generation in the universal motors, we try to measure the noise pattern near the noise source by using two coils which are installed for direct detection of the time varying arc current and the noise levels in the range of 0.15_??_5 MHz.
The experimental results show that the noise levels depend on the time derivatives (di/dt) of the arc current and the wide spread of noise levels are caused by randomness of arc quenching. We also discuss the propagation of noise and the comparison with the conventional evaluation of EMI, using an appropriate procedure of the obtained experimental data.

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3-D optimization method using the finite element method and the Rosenbrock's method, is developed to apply to the optimal design of permanent magnet type of retarder. The Rosenbrock's method has an advantage that the optimal value can be obtained within small number of iterations compared with the stochastic methods, such as simulated annealing method. As the number of searching iterations of the Rosenbrock's method is affected by the initial condition and the constraints, the experimental design method is introduced to the determination of appropriate values of them. A technique for modifying the hexahedral mesh is conceived in order to change the shape of machine at each iteration for the optimization. The obtained result is discussed from the viewpoint of flux and eddy current distributions. It is shown that the number of iterations and CPU time can be reduced by using the experimental design method. The braking torque is increased about 50% by using the optimization method.

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The authors previously proposed a new brushless self-excited three-phase synchronous generator which utilizes the 2nd-space harmonic component of armature reaction field to produce a field current. Its operating principles and basic characteristics were clarified by experiment. This generator has the following advantages: (1) it can be made with a brushless structure without an ac exciter; (2) an output voltage of almost constant value can be obtained without an automatic voltage regulator (AVR); and (3) the generator itself has high quick-response characteristics.
This paper introduces a method of predicting the steady-state performance of the aforementioned generator. In the analysis, a magnetic circuit is drawn from the configuration of magnetic path of the generator, and an equivalent circuit is derived by using a duality between electric and magnetic circuits. Using this equivalent circuit, the generator's steady-state performance is theoretically predicted, and confirmed through experiment.

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Traffic congestion has been a serious problem in urban road networks. The dynamic route guidance system is regarded as an important strategy in relieving the congestion.
This paper discusses on the effectiveness of the dynamic route guidance system. First, we propose the route choice model and the traffic flow model for simulation analysis. Secondly, we propose the simulation framework to evaluate various types of dynamic route guidance in a large scale road network. Simulation results show that the multiple routes guidance is better than the dynamic shortest route guidance in high system penetration rate because of autonomous dispersions of each vehicle.

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