• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.56 no.11
• /
• pp.1930-1936
• /
• 2007

According to previously published paper the phase advance angle is adopted to the BLDC motor drive with high speed. The report proposed describes the optimum algorism that phase current is in phase with the initial flat region of back EMF. This report studies the need of more leading phase advance angle compared with in phase concept between phase current and back EMF. In case of high reactance this report proposes the more phase advance angle than in phase. The test results more rms value of phase current and output power due to more phase advance angle than in phase. It will be helped the high power operation of BLDC motor at high speed.

• Proceedings of the KIEE Conference
• /
• 1995.07a
• /
• pp.321-324
• /
• 1995

Switched reluctance motors and drives are increasingly used in high speed applications due to their robust mechanical structures, low inertia, and reduction in the rotor losses. The turn-on angle has to be advanced as the motor speed increases, but it may cause the starting problem in some rotor positions. In this paper, the characteristics of the maximum speed and input voltage with the advance angle at high speeds is investigated. To overcome the starting problem and reduce the torque ripple, conduction overlapping is added in adjacent phases. The effectiveness of conduction overlapping is verified through the simulation and experiments.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.11 no.6
• /
• pp.30-36
• /
• 2003

Variable valve timing(VVT) mechanisms are used widely for improving fuel consumption and reducing emissions. Most of application, however, are limited in the DOHC engine. Dual equal retard/advance strategy is relatively simple one and can be applied to both SOHC and DOHC engines. In this study, effects of dual equal valve timing retard/advance are investigated to observe the feasibility of VVT system on an SOHC SI engine. The result shows that fuel economy and emissions are improved in the dual retard condition due to increased internal EGR. Some amount of increase in volumetric efficiency can be achieved by advancing valve timing at low speed and by retarding at high speed. In this case, however, full load power is not so much improved as the volumetric efficiency increases because of severe knock. In the dual advance condition, there is no merit in the fuel economy and emission.

• Journal of the Korean Institute of Navigation
• /
• v.15 no.4
• /
• pp.27-39
• /
• 1991

One practical method has already been proposed for predicting the characteristics of ship manoeuvring motions at relatively high advance speed [19]. Howeverf, this method can hardly be applied to motions of ships in starting, stopping, backing and slow steaming conditions, even though such extensive motions are of vital importance from a safety point of view particularly in harbour areas. The method presented here aims at predicting the characteristics of ship manoeuvring at low advance speed, which covers starting, stopping, backing and slow steaming conditions. The force mathematical models at large angles of incidence to the hull as well as under the wide range of propeller operations are formulated. Simulations of various manoeuvres at low advance speed are carried out for two types of merchant ship, I.e. a LNGC and a VLCC. Comparisons between simulations and corresponding full-scale measurements [10], [15] or free-running model tests [6],[10] provide a first verification of the proposed mathematical models.

• Journal of the Society of Naval Architects of Korea
• /
• v.29 no.3
• /
• pp.90-101
• /
• 1992

Some practical methods have already been proposed for predicting the characteristics of ship manoeuvring motions at relatively high advance speed. However, these methods can hardly be applied to motions of ships in starting, stoppint, backing and slow steaming conditions, even though such extensive motions are of vital importance from a safety point of view particularly in harbour areas. The method presented here aims at predicting the characteristics of ship manoeuvring at low advance speed, which covers starting, stopping, backing and slow steaming conditions. The force mathematical models at large angles of incidence to the hull as well as under the tilde range of propeller operations are formulated. Simulations of various manoeuvres at low advance speed are carried out for two types of merchant ship, i.e. a LNGC and a VLCC. Comparisons between simulations and corresponding full-scale measurements or free-running model tests provide a first verification of the proposed mathematical models.

• Proceedings of the KSR Conference
• /
• 2007.05a
• /
• pp.1253-1261
• /
• 2007

Investigated domestic railway specialists' suggestion about efficient role division of labor of government, industrial and academic for South Korea style High Speed Railway(HSR350x) advance into overseas markets. This investigation was gone by question about advance into overseas markets of railroad industry and there is the purpose to utilize to basis data to establish direction of railroad industry advance into overseas markets promotion policy hereafter.

• 제어로봇시스템학회:학술대회논문집
• /
• 2000.10a
• /
• pp.232-232
• /
• 2000

switched reluctance motors and drives are increasingly used in industrial applications due to their robust mechanical structure, low inertia and reduction in the rotor losses. As the motor speed increase turn on angle must be advanced to build up phase current. When C-dump converter is applied to switched reluctance motor, the capacitance of dump C has to have proper value. In this paper advance angle for a switched reluctance motor and capacitance of dump C are investigated. Then proper advance angle and the capacitance of dump-C are propose for the industrial low voltage SR motor.

• Proceedings of the KSR Conference
• /
• 2007.11a
• /
• pp.1835-1842
• /
• 2007

The purpose of this paper describes the changes of TGV & ICE series' nose shape by increasing train speed and according to the periodical characteristics. As the speed increases, the length of the nose shape trends to lengthen longer. But the nose shape length does not increase as speed improves by optimized nose shape to reduce aerodynamic drag and micro-pressure wave in tunnels. TGV & ICE series' nose shape can be classified into Advanced paraboloid type, Shape-nosed type, Organic double-edged type and Flat-nosed type by the advance research(the changes of Shinkansen vehicle' nose shape) of high speed railway. Because it trends to be diversified and characterized more and more. This paper analyzed and introduced as TGV & ICE series' nose shape by top 2 nation (Germany, France) and high speed railway in the past years(1980-2007) for their railway design trends by new positioning(Advance research).

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.46 no.1
• /
• pp.56-69
• /
• 2010

This study was intended to determine the maneuverability of the vessel CHARMBADA. When the rudder angle was at $10^{\circ}$, $20^{\circ}$ and $30^{\circ}$, the maximum advance by slow, half and full ahead were varied in the range of 523.6-131.3m, 528.8-177.2m and 530.6-219.7m, respectively. The maximum transfer was 799.9-181.3m, 792.1-232.8m and 807.7-316.9m, respectively. The turning circle ability was better during starboard turning. When the rudder angle was $10^{\circ}$, $20^{\circ}$ and $30^{\circ}$, variation in the maximum advances was 392.0m, 245.0m and 153.0m. The maximum transfer was 528.0m, 339.0m and 218.0m, respectively based on the regression equations. As the rudder angle became bigger, the maximum advance or maximum transfer became smaller by the exponential function. The advance inertia took 127sec, 145sec, 181sec each until the vessel speed was 7.0konts, 12.0konts, 17.0konts. The static inertia took 245sec, 269sec, 300sec each until the vessel speed was under 2.0konts and the advance distance was 114.4m, 181.2m, 197.0m each. Accordingly, the static inertia was inclined to increase to scale according to the increase in vessel speed. For the CHARMBADA, the smaller the rudder angle was, the much bigger the turning circle became due to adhesion to the skeg, thereby lowering the vessel's turning ability.

• Journal of the korean Society of Automotive Engineers
• /
• v.7 no.3
• /
• pp.64-73
• /
• 1985

In order to control ignition advance angle, this system is designed with Z-80 CPU, CTC (counter Timer Circuit), PIO(Parallel Input Output), A/D Converter and Memory, etc. Serial pulses from speed sensor and analog voltage from pressure sensor are converted to digital data. In order to reduce the error of ignition advance angle output, the reference of ignition advance angle output is set 56.25 before TDC(Top Dead Center). The table of ignition advance angle and program which have a main routine and subroutines are written into ROM ( 1 K-byte). The experimental result of this system is correspondent to the theoretical values of proposed ignition advance angle table. This system can be utilized to any other type of 4 cylinder vehicles for advance angle control by changing software.