Showing papers by "Mitsubishi Electric published in 1983"
TL;DR: A knowledge based system for automatic control of a power system in the restorative state is developed, and efforts are made to represent heuristics by a set of knowledge the goal of which is to restore the power supply without overloading any transmission line.
Abstract: A knowledge based system is developed for automatic control of a power system in the restorative state. System operator's heuristics seem to play a central role during the course of system restoration. So efforts are made to represent those heuristics by a set of knowledge the goal of which is to restore the power supply without overloading any transmission line. While the overload check is a numerical computation, reasoning in the knowledge based system is a symbolic computation. A method to link these two different types of computation is proposed. The knowledge based system is expected to serve managing a large scale power system in the restorative state.
275 citations
TL;DR: In this paper, the authors studied the charge accumulation and its mechanisms based on the experiments of post and conical epoxy spacers subjected to high dc voltages in compressed SF 6 gas.
Abstract: The charge accumulation and its mechanisms are studied based on the experiments of post and conical epoxy spacers subjected to high dc voltages in compressed SF 6 gas. The charge measurement is performed using electrostatic probe and dust figure techniques. The charge accumulation is strongly influenced by the surface condition of epoxy spacer. Heterocharge deposits locally on the surface of untreated spacer. The flashover voltage of highly charged spacer decreases considerably at the time of polarity reversal. In the case of epoxy surface treated with horning, only a small quantity of charge is deposited uniformly on the surface of spacer. The mechanism of inhomogeneous surface conduction is suggested by the local surface charging on the untreated spacer. Field emission is also found as the other charging mechanism on the conical spacer set in rough finish electrode system.
156 citations
TL;DR: Using the molecular beam epitaxial (MBE) technique, CdTe and Hg1-xCdxTe have been grown on Cr-doped GaAs sub-strates.
Abstract: Using the molecular beam epitaxial (MBE) technique, CdTe and Hg1-xCdxTe have been grown on Cr-doped GaAs (100) sub-strates A single effusion cell charged with polycrystal-line CdTe is used for the growth of CdTe films The CdTe films grown at 200 °C with a growth rate of ~ 2 μm/hr show both streaked and “Kikuchi” patterns, indicating single crystalline CdTe films are smoothly grown on the GaAs sub-strates A sharp emission peak is observed at near band-edge (7865 A, 1577 eV) in the photoluminescence spectrum at 77 K For the growth of Hg1-xCdxTe films, separate sources of HgTe, Cd and Te are used Hg06Cd04Te films are grown at 50 °C with a growth rate of 17 μm/hr The surfaces are mirror-smooth and the interfaces between the films and the substrates are very flat and smooth As-grown Hg06Cd04Te films are p-type and converted into n-type by annealing in Hg pressure Carrier concentration and Hall mobility of an annealed Hg06Cd04Te film are 1 × 1017 cm−3 and 1000 cm2/V-sec at 77 K, respectively
71 citations
Proceedings Article•
08 Aug 1983TL;DR: The methodology to deal with the behavior of a dynamical system such as plant controllers in the framework of Temporal Logic is described and an automatic synthesis of control rules can be reduced to a simple decision procedure on the w -graph.
Abstract: This paper describes the methodology to deal with the behavior of a dynamical system such as plant controllers in the framework of Temporal Logic. Many important concepts of the dynamical system like stability or observability are represented in this framework. As a reasoning method, we present an w -graph approach which enables us to represent the dynamical behavior of a given system, and an automatic synthesis of control rules can be reduced to a simple decision procedure on the w -graph. Moreover, the typical reasoning about the time-dependent system such as a causal argument or a qualitative simulation can be also treated on the w -graph in the same way.
63 citations
TL;DR: In this article, a simple synthesis method of a power system stabilizer (PSS) was developed by combining the frequency response method and the pole assignment method, which enables synthesis in a multimachine system and is easily incorporated into an eigenvalue program for the power system.
Abstract: A simple synthesis method of a power system stabilizer (PSS) was developed by combining the frequency response method and the pole assignment method. This method enables synthesis in a multimachine system and is easily incorporated into an eigenvalue program for the power system. Although there are limitations of the model accuracy, the damper winding, the governor system and the load characteristics can be considered in the synthesis.
62 citations
TL;DR: In this article, two kinds of fiber-optic sensors for electric current and voltage were tentatively fabricated by using Faraday and Pockels' effects of a Bi 12 GeO 20 (BGO) single crystal.
Abstract: By using Faraday and Pockels' effects of a Bi 12 GeO 20 (BGO) single crystal, two kinds of fiber-optic sensors for electric current and voltage were tentatively fabricated. The optimum design of these sensors and their performances were investigated. It was verified that the BGO crystal is very available for either of the current and voltage sensors with regard to their sensitivity and stability. As for the experimental results, the minimum detectable magnetic field of 10-2Oe and the temperature dependence within ±2 percent in the temperature range of -25 to 85°C was obtained for the current sensor, while for the voltage sensor the sensitivity of 10-3V and the temperature dependence within ± 0.5 percent was in the same temperature range.
48 citations
TL;DR: A fast transient stability program for an array processor connected to a host computer (DEC VAX-11/780) has been developed by using unique technique for improving the speed of transient stability studies.
Abstract: A fast transient stability program for an array processor (FPS AP-120B) connected to a host computer (DEC VAX-11/780) has been developed by using unique technique for improving the speed of transient stability studies. They are solving techniques of differential equations using a modified Euler method, effective use of vector operation, and programming techniques adapted to the array processor.
44 citations
TL;DR: This paper deals with the attitude behavior of a spacecraft with a rotor during extension of flexible appendages using a spacecraft modal coordinate scheme based on the method of multiple scales.
Abstract: This paper deals with the attitude behavior of a spacecraft with a rotor during extension of flexible appendages. The analysis is based on the method of multiple scales. The equations of motion are formulated using a spacecraft modal coordinate scheme. The analytical expressions for the attitude behavior of the spacecraft are obtained. The extension of the appendages plays a significant role in the stability of the attitude motion of the spacecraft: In some cases, the attitude motion of the spacecraft will become unstable.
42 citations
TL;DR: From the evaluation of dynamic characteristics, it was shown that the 16K RAM using the cell had a sufficient operating margin, and the criteria use only static conditions for read/write/retain operations.
Abstract: Describes design criteria for high-density low-power static RAM cells with a four-transistor two-resistor configuration. The states of the cell latch are expressed by a DC stability factor introduced from transfer curves of the inverters in the cell. The criteria use only static conditions for read/write/retain operations. The designed cell, considering mask-misalignment, measured 22.8/spl times/27.6 /spl mu/m with 2.5 /spl mu/m layout rules. From the evaluation of dynamic characteristics, it was shown that the 16K RAM using the cell had a sufficient operating margin.
39 citations
TL;DR: A novel type of fiber-optic acceleration sensor was constructed of a photoelastic substance such as isotropic epoxy resin, DAP (diallylphthalate polymer, or LiNbO3 single crystal, and acceleration from 10−3 to 30 G was accurately measured in the frequency range from dc to 3 kHz.
Abstract: A novel type of fiber-optic acceleration sensor was constructed of a photoelastic substance such as isotropic epoxy resin, DAP (diallylphthalate polymer), or LiNbO3 single crystal. By a weight placed on the upper surface of the rectangular rod of photoelastic material, stress-induced birefringence is brought about in response to vibrational acceleration. With this sensor, acceleration from 10−3 to 30 G was accurately measured in the frequency range from dc to 3 kHz.
34 citations
27 Jun 1983
TL;DR: A program which generates test patterns for scan design circuits with tri-state modules and bidirectional terminals by using shift-in function of SRLs by using path sensitization technique with 14 signal values.
Abstract: This paper describes a program which generates test patterns for scan design circuits with tri-state modules and bidirectional terminals. The test generation procedure uses a path sensitization technique with 14 signal values. The principal features of this program are test generation with automatic decision of I/O mode of bidirectional terminals, generation of test sets for high impedance state, and generation of test sets for system clock control circuits of shift register latches (SRLs) by using shift-in function of SRLs.
TL;DR: The new timing verification method using the delay model is evaluated with respect to delay-time accuracy and execusion time in a logic LSI and circuit simulator accuracy is obtained in the short computer run time of a logic simulator.
Abstract: The propagation delay time of the ED MOS logic gate is precisely analyzed considering input waveform and loading conditions. According to theoretical consideration and circuit analysis, the rise mode delay time tpLH is approximated as a function of the output capacitance of only the gate concerned. The fall mode delay time t.pHL is determined by the input capacitance and output capacitance of the gate concerned. These results allow the easy implementation of the delay model into a logic simulator. A precise delay simulation is attained by considering the delay components, corresponding to each input node, at the output side of the logic element. The propagation delay times of the transmission gate are precisely analyzed. The operations of the transmission gate are divided into two modes; synchronous mode and asynchronous mode. Corresponding to each mode, the transmission gate, the preceding gate, and the succeeding gate have two kinds of delay times. To simulate delay times of each gate precisely, models which treat these three logic elements as one primitive element in a logic simulator have been proposed. The new timing verification method using the delay model is evaluated with respect to delay-time accuracy and execusion time in a logic LSI. Through this method, circuit simulator accuracy is obtained in the short computer run time of a logic simulator.
TL;DR: In this paper, a mechanism for the growth of whiskers was proposed, based on the experimental results of micro-Auger electron spectroscopy and X-ray micro analysis.
Abstract: Observations by micro Auger electron spectroscopy and X-ray micro analysis have been made on tin films electroplated on substrates of brass or zinc-coated copper, and on whiskers grown on the films. Direct experimental evidence has shown the existence of zinc and oxygen atoms on the surfaces both of the whiskers and the films. Copper atoms have also been detected in the whiskers and the films. A mechanism for the whisker growth is proposed, based on these experimental results. After electroplating, zinc atoms migrate onto the tin surface and bind there with oxygen atoms. At this stage, the nuclei of whiskers are formed, and the whiskers begin to grow with the aid of the internal stresses caused by the recrystallization of tin grains and/or the formation of intermetallic compounds of tin with copper.
01 Dec 1983
TL;DR: A practical method for generating optimal schedules for online train traffic control in disturbed situations and it is shown that each subproblem generated in the second part, which is a linear programming problem, can be easily calculated without using the ordinary simplex method.
Abstract: A practical method for generating optimal schedules for online train traffic control in disturbed situations is proposed. This scheduling problem is formulated to a 0-1 mixed integer programming problem. The method of solution proposed here is mainly divided into two parts: the first part generates a suboptimal solution by a heuristic method based upon "Production System", and the second produces an optimal one by the branch-and-bound method using the above sub-optimal value for the initial bound. It is shown that each subproblem generated in the second part, which is a linear programming problem, can be easily calculated without using the ordinary simplex method. Some examples show that the proposed method has enough efficiency for practical use in both computational time and storage.
TL;DR: In this article, a three-stacked tandem type amorphous solar cell which consists of aSi:H and a-SiGe:H with a size of 10 by 10 cm was obtained.
Abstract: An efficiency of 8.6 % by the three-stacked tandem type amorphous solar cell which consists of a-Si:H and a-SiGe:H with a size of 10 by 10 cm was obtained. This tandem type solar cell showed stable characteristics for the prolonged light exposure.
TL;DR: In this article, the measurement of magnetic force wave was successfully accomplished by fitting flux-detecting coils on all stator teeth, and through the analysis of experimental results, a series of magnetic noise emitting mechanism and correlation among magnetic noise, vibration, frequencies and modes of both stator core and magnetic forces were found.
Abstract: This paper presents an experimental study on magnetic noise of an induction motor. The measurement of magnetic force wave was successfully accomplished by fitting flux-detecting coils on all stator teeth. Through the analysis of experimental results, a series of magnetic noise emitting mechanism and correlation among magnetic noise, vibration, frequencies and modes of both stator core and magnetic forces were found.
Patent•
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TL;DR: In this article, an on-load tap changer with diverter switch circuits is presented, where diverter switches are connected between an output terminal and a plurality of tap selecting arms (1, 2) and resistors are employed as current-limiting bridge elements.
Abstract: An on-load tap changer wherein diverter switch circuits each of which is a series connection of a main switch A, B and an auxiliary switch C, D are connected between an output terminal (13) and a plurality of tap selecting arms (1, 2) and wherein resistors R1, R2 are employed as current-limiting bridge elements. The main switch has a movable contact (7, 8) connected to the output terminal, the auxiliary switch has a movable contact (11, 12) connected to a stationary contact (5, 6) of the main switch and a stationary contact (9, 10) connected to the odd-input terminal (3,4) and the current-limiting resistors are respectively connected in parallel with the main switches. The switches are preferably vacuum switches.
TL;DR: In this article, the authors have developed a metal enclosed converter station for HVDC transmission with compressed SF 6 gas insulation, metal oxide surge arresters, DCCT, PT's, switchgears, connecting-buses and other components in a converter station.
Abstract: Compressed SF 6 gas insulation will give a promising way to obtain a reliable, compact, and economical converter station for HVDC transmission. Some of the outcomes of a project in which we have developed a metal enclosed converter station are presented in the paper. Thyristor valves, metal oxide surge arresters, DCCT, PT's, switchgears, connecting-buses, and other components in a converter station have been developed. All of these equipment have been subjected to a long term voltage endurance test at 1.3 pu of their rated voltage at ±125 kV. A control and protection system has also been developed. Fundamental control function has been digitalized to secure reliability, accuracy and flexibility of the dc plant control. A 9.6 MW back-to-back miniplant rated at 16 kV, 600 A has been constructed to gain an operational experience of the new gas insulated converter station. In spite of the rated voltage of the system, all the equipment in the system is rated at 125 kV line to ground voltage and stressed at the voltage using a separate dc bias voltage source. Based on the experiences obtained in the project, a conceptional design of a ±500 kV 5 GW converter station will also be discussed. Technical feasibility and benefits of introducing the gas insulation, metal oxide dc arresters and digitalized control have been investigated through the development of the full scale dc equipment rated at 125 kV and a 9.6 MW back-to-back miniplant which is fully gas insulated and controlled by the digitalized scheme.
TL;DR: In this article, photo-induced defects in hydrogenated amorphous silicon (a-Si:H) and a-Si 1−xGex:H were studied and their effect on opto-electronic properties were analyzed.
01 Feb 1983
TL;DR: A new type Rear Brake Lock-up Control System which is mounted on Mitsubishi Starion gives a high braking stability regardless of the road conditions, and minimizes the body vibration and the pulsative reaction on the brake pedal to achieve a comfortable feeling during the brake application.
Abstract: This paper describes a new type Rear Brake Lock-up Control System which is mounted on Mitsubishi Starion. This system meets all the requirements of the ECE R13, Annex 13, gives a high braking stability regardless of the road conditions, and minimizes the body vibration and the pulsative reaction on the brake pedal to achieve a comfortable feeling during the brake application. It would be expected that the adoption of this system could contribute greatly to the reduction of car accidents caused by the rear wheel lock-up.
01 Jan 1983
TL;DR: A new visual sensor to be used for the path correction of arc-welding by means of an optical pattern projection method using an LED scanning spot and a two-dimensional photo sensitive position detector with the aid of a microprocessor.
Abstract: This paper describes a new visual sensor to be used for the path correction of arc-welding By means of an optical pattern projection method using an LED scanning spot, the image patterns of various welding objects have been detected effectively by a two-dimensional photo sensitive position detector with the aid of a microprocessor The sensing head could be compactly formed so as to be mounted to the robot hand
TL;DR: In this article, a new coordinated synthesis method of applying power system stabilizers (PSS) was developed by combining eigenvalue sensitivity analysis and linear programming, which is simultaneously able to select the generators to which the PSS can be effectively applied and to synthesize the adequate transfer functions of the PS for these generators.
Abstract: A new coordinated synthesis method of applying power system stabilizers (PSS) was developed by combining eigenvalue sensitivity analysis and linear programming. This method is simultaneously able to select the generators to which the PSS can be effectively Applied and to synthesize the adequate transfer functions of the PSS for these generators. The proposed itethod is used to synthesize the coordinated PSS for a 12-machine system.
TL;DR: In this paper, the grain boundaries in laser-recrystallized polycrystalline silicon (polysilicon) islands are found to be arranged along with the laser scan direction, and are connected to the electrical characteristics of MOSFETs fabricated in polysilicon islands.
Abstract: Directions of grain boundaries in laser-recrystallized polycrystalline silicon (polysilicon) islands are found to be arranged along with the laser scan direction, and are connected to the electrical characteristics of MOSFETs fabricated in polysilicon islands. In the case of the laser scan parallel to the channel direction, grain boundaries work as fast-diffusion paths of arsenic from source and drain into the channel, and results in a decrease of effective channel length of MOSFET. But in the case of the laser scan perpendicular to the channel direction, there are few grain boundaries contributing to diffusion paths of arsenic. The maximum electron mobility of 590 cm2/V sec approaching to that on a single crystalline silicon can be obtained in devices with a channel length of 3 µm, though grain boundaries work as an additional potential barriers for carriers. A nine stage ring oscillator is fabricated by applying these results. The minimum propagation delay of 38 nsec is obtained.
27 Jun 1983
TL;DR: An accurate delay modeling of MOS gates at the logic level which takes account of the effects of not only the loading capacitance but also the slope of the input waveform is presented.
Abstract: This paper concerns an accurate delay modeling of MOS gates at the logic level. The model takes account of the effects of not only the loading capacitance but also the slope of the input waveform. A logic simulator which uses multiple rise/fall delays based on the model is described. Some experimental results are also presented.
TL;DR: In this article, a thermal conduction plate is individually bonded to the back surface of a large-scale integrated (LSI) chip by soft solder and is arranged in close proximity to the inner surface of the cap, when the chip is assembled together with the cap and substrate.
Abstract: The technology of new packages with high thermal conduction performance, simplified structure, and also high reliability for flip chip devices is described. In order to obtain high thermal conduction, a thermal conduction plate is individually bonded to the back surface of a large-scale integrated (LSI) chip by soft solder and is arranged in close proximity to the inner surface of the cap, when the chip is assembled together with the cap and substrate. The cavity is then filled with a gas which has a high thermal conductance characteristic. As a result, a large part of the heat is effectively drawn off from the back side of the chip to the air-cooling fin through the plate and across the narrow gap filled with the gas. A series of experiments were conducted on a single chip package and a nine chip multichip module. These tests indicated a junction-to-fin thermal resistance of 3.2°C/W for the single chip package and 4.8°C/W as a worst case in the module. In addition a computer model analysis for thermal conduction was studied using a program named TNET-2. It was found that the calculated values corresponded closely to the measured data. More detailed descriptions of packages and results of studies are presented and discussed here.
TL;DR: In this paper, the effect on evaporation rates of air content in flashing water was investigated experimentally in a scaled-down open-channel flash evaporator, where water was at 97°C-98°C, the flash-down temperature differences were up to about 2°C and air content was up to 6.32 ppm.
TL;DR: In this article, the finite element method has been applied to clarify the relation between magnetic characteristics of the electrical steel and power transformer iron losses, and three material constants which represent the magnetic characteristics are used for this study.
Abstract: The finite element method has been applied to clarify the relation between magnetic characteristics of the electrical steel and power transformer iron losses. Three material constants which represent the magnetic characteristics are used for this study. The computed results have contributed to understanding of factors which increase the transformer iron losses.
TL;DR: In this article, the authors deal with overvoltages caused by self-excitation in a separated power system, which has some generators, heavy load and large shunt capacitance of underground cables.
Abstract: This paper deals with overvoltages caused by self-excitation in a separated power system, which has some generators, heavy load and large shunt capacitance of underground cables and/or shunt capacitors. The condition of stability in a separated power system is analyzed and a comparison with the experimental result is presented.
TL;DR: An improved stroke matching method for the recognition of handprinted Kanji characters using the stroke feature and two additional global features with a recognition rate over 90% has been obtained.
TL;DR: In this article, a thyristor valve for HVDC transmission insulated by compressed SF 6 gas has been developed, where the valve is cooled by the forced circulation of the insulating gas with a blower.
Abstract: A thyristor valve for HVDC transmission insulated by compressed SF 6 gas has been developed. The valve is cooled by the forced circulation of the insulating gas with a blower. Valve unit up to the voltage and current ratings of 250 kV and 3,000 A can be housed in a metal tank and the valve is transportable on a trailer fully constructed. A metal enclosed converter for 500 kV HVDC power transmission for example, may be constructed by connecting the units to form a twelve pulse converter.