For optimum design of photovoltaic power systems, it is very important to estimate their annual maximum amount of output. In general, the annual maximum amount of output has been calculated by using photovoltaic module efficiency under irradiance of 1kW/m² at AM 1.5 with solar cell temperature of 25°C. Since the spectral distribution of solar radiation changes with weather, season and time, the efficiency of solar cells is not always constant. This paper describs a method evaluating the maximum amount of output in photovoltaic modules, “the spectral method”, by using the measured annual spectral solar radiation and the spectral response of various photovoltaic modules.
The calculated values using the spectral method agreed well with the measured values for amorphous silicon photovoltaic modules from March, 1991 to February, 1992. The spectral method proved most effective for optimum design of amorphous silicon photovoltaic power systems.

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In this paper, a novel harmonic injection PWM method is proposed for harmonic reduction. The third harmonic is injected to the reference voltage, of which amplitude and phase angle are regulated so that the dominant ripple torque components are reduced.
In a large capacity power converter, GTOs are commonly used as the switching devices and a multiple configuration of unit power converters has been applied. The use of GTOs allows higher voltage and larger current to be handled. However, it results in increased harmonics, because of their relatively low switching frequency of about 500Hz. Therefore, harmonic reduction method for large capacity applications is of great interest, which is suitable for a multiple power converter without increasing the cost. The harmonic injection PWM fulfills the requirement.
The harmonic components of output voltage, output current and torque when a harmonic component is injected are analyzed in detail. The most suitable amplitude and phase angle are derived from theoretical analysis. Simulation results show the effectiveness of the method.

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For the rectifier circuits with small capacity such as for consumer electronics and appliances, the capacitor input type rectifier circuits are generally used. The various switching regulators with such capacitor input rectifier have become more and more used, typically such as for the television set. Consequently, various harmonics much generate in the power system, so hereafter harmonic problems will become more serious. On such background, in this paper, by means of the reduced input capacitance, the authors propose some techniques to improve the current harmonic characteristics in the input power supply for the conventional forward converter type switching regulator.
Secondly, we discuss the harmonic cancellation characteristics by the parallel connection of the conventional converter and the proposed one. For such parallel connection, the current harmonics in the power system, especially the lower order harmonics such as the fifth or seventh, can be largely reduced by means of the cancellation of harmonics due to the phase difference of the harmonics between conventional converter and the proposed one.

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With introduction of automated production lines, it is becoming more difficult to manage manufacturing systems. Many scheduling methods have been researched to improve the efficiency of manufacturing systems, yet they have not been utilized in large scale and complex systems because of many requirements and constraints in real manufacturing systems and lack of know-how for large scale and complex production control.
This paper presents a hierarchical scheduling method for an on-line production line control, which consists of a strategic level scheduler (SLS) and operational level schedulers (OLS). The SLS aims at making a schedule referred by the OLS. The schedule solved by the SLS satisfies some constraints, and it is generated by a scheduling algorithm based on a human planning procedure and a temporal constraint propagation mechanism. To obtain a desired result (expected throughput), it is necessary to control the production line to obey the higher level decision. The OLS aims at the on-line control of the production line and is based on the know-how of the supervisor.
This hierarchical method is evaluated by discrete event simulations before introducing it into real production lines. The results show that this method is more useful than the practical operation subject to minimizing of lateness and tardiness to dynamic environment such as failures of machines or AGVs.

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In this paper we propose a heuristic procedure to solve the routing phase of delivery scheduling problem. Aiming at fast response, a beam search based decision procedure is utilized. In this research, a new evaluation rule named as “the most willing neighbor” is applied. The new rule retains the simplicity of the nearest neighbor rule, and overcomes its weak points. Three applications are presented and compared with the results obtained in 20 runs of the well-known 3-opt procedure. The proposed system offers flexibility and high quality solutions with very fast response.

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This paper discusses an application of Robust Model Matching (RMM) to the spill position control of a fuel injection pump. Since the fuel injection servo mechanism is soaked in fuel oil, the parameters of the plant vary due to differences in the viscosity coefficient caused by wide changes in temperature. The invariable fuel injection characteristic is required to meet the demands of the drivability, exhaust emissions and fuel consumption, even though the parameters change. The RMM is an idea which makes up a robust control system against parameter uncertainties.
In this paper, we design a robust discrete-time control system based on the RMM: (1) For the low sensitivity, to make small pulse transfer functions from equivalent disturbances to controlled variables. (2) For the robust stability, to increase the margin of pulse transfer functions from conceptual inputs to control variables. The experimental results show that this robust compensator makes up a robust control system against the parameter variations due to the change in temperature. And it is confirmed that the idea of the RMM is effective for the fuel injection pump which includes the variations, identification errors, friction, hysteresis and delay time of the calculation.

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The MAGLEV (magnetically levitated train) is now well along in development testing in Japan. The MAGLEV power source needs to supply a variable voltage and variable frequency source, and contains many higher harmonics, which causes many troubles such as inductive interference. Thus it is necessary to clarify the impedance frequency characteristics of the MAGLEV power feeding circuit. In view of this situation, experiments and investigations concerning the impedance frequency characteristics of the coils for propulsion and the power feeding circuit at the Miyazaki test track have been performed but a theoretical analysis had not been done.
A theoretical analysis was therefore done in this paper by applying the inverted L equivalent circuit to the coil for propulsion, from which the characteristics of the coils for propulsion were analyzed.
In addition the characteristics of the power feeding circuit could be clarified by assuming the equivalent circuit of the power feeder line.
As a result, the measured values and calculated values were almost equal in both the characteristics of the coils for propulsion and those of the power feeding circuit.

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The matrix converter Prof. Venturini proposed is very simple in structure and has powerful controllability. But, there are few applications especially in power electronics fields. This seems to be mainly caused by the fact that we didn't have such power devices that were fast enough to suppress ringing oscillations in the supply lines and big enough to pay for more devices and more complicated control circuits than in conventional DC-link converter-inverter systems. Now we've static induction thyristors (SIThs) and new possibility for the matrix converter is opened for us.
In this paper, we describe the new control strategy which is simple and practical and allows to generate the output voltage of 0.866 times the supply voltage. We also propose the new firing sequences which eliminate voltage and current spikes. Steady state and distortion characteristics of the prototype PWM matrix converter with SITh are shown in the paper.

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Large DC motors for driving rolling mills should have a compact motor size and tew injurious commutation spark. Good motor performance is got with a no-spark commutation of the brushes. Commutation improvements have been investigated, but problems still remain with commutation leading edge sparking and trailing edge sparking for the progress of running times of the brushes.
We developed a new interpole structure to get no sparking on the leading edge. A magnetic flux adjustment winding and a leakage compensation winding is provided adjacent to the radial inner end of the interpole core to improve flux distribution under the interpoles. This approach is effective because leading edge sparking is due to unsymmetrical magnetic flux distribution under the interpoles.
Further, we developed a commutation control method to maintain the best conditions on the commutation trailing edge of the brushes. The mothod adjusts the interpole flux according to the commutating conditions.
We describe the circuit construction of the commutation control here. Confirmation is made of the reduction effects on the commutation leading and trailing edge sparking of the brushes when using the commutation control system for a 2, 000kW DC motor.

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