• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.222-227
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• 2004

Korean High Speed Train(KHST) has been tested on the high speed test line in Osung site, since it was developed through the G7 Project Plan in 2002. It was also tested on the conventional line such as KyongBu and Honan Line to know the possibility of increasing the limited speed for the high speed trains. This paper introduces the method to improve the speed on the conventional line with body lateral acceleration among the several considered issues and explains the parameters related to those analysis, such as the cant deficiency, the radius of curve, speed and etc. When a train pass on the curved track, the lateral accelerations of body are divided into the quasi-static and the maximum accelerations according to the UIC 518 which is the international specification for testing and approval of railway vehicles from the point of view of their dynamic behaviour, especially for safety and ride comfort. This paper shows that it is safe and comfort from the results of test when KHST runs on the conventional line with the curves and proposes that the limited speed of conventional curved line could be changed to a little higher speed if the analysises of other fields are completed.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.2 no.3
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• pp.295-302
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• 1998

In this paper, a new auto-tuning PI controller for the speed servo system of a PMSM is designed by using limited step response characteristics. The method is proposed that gets information about auto-tuning of PI regulator by the injection of step input, called limited input, during a transient response time of control. System parameter estimation and speed control could be continuously executed. This means that in despite of system uncertainty the system information obtained by limited input can be continuously applied to the PI regulator. We demonstrate the effectiveness of the proposed auto-tuning algorithm through simulation and experiment result of the speed control for a PMSM having monotone increasing step response.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.215-218
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• 2000

The windup phenomenon appears and degrades control performance when a controller with integrating action is used and the plant input is limited. An anti-windup integral -proportional(IP) controller is proposed for the variable-speed motor drives and it is experimentally applied to the speed control of a vector-controlled induction motor driven by a pulse width modulated (PWM) voltage source inverter(VSI). Although the operating conditions like motor load and speed command is changed under the limited plant input it is experimentally verified that the speed response has much improved performance such as no overshoot and fast settling time and the maximum plant input is also effectively utilized.

• Journal of Power Electronics
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• v.2 no.2
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• pp.130-138
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• 2002

The windup phenomenon appears and degrades control performance when a controller with integrating action is used and plant input is limited. An anti-windup integal-proportional(IP) controller is proposed for the variable-speed moter drives and it is experimentally applied to the speed control of a vector-controlled induction moter driven by a pulse width modulated (PWM) voltage source inverter (VSI). The consistency range of the IP controller is firstly derived and the intergal state is controlled to salisfy always the consistency range according to whether the the controller output is saturated or not. Although the operating condition like moter load or speed command is changed under the limited plant input, It is expermentally verified that the speed response has much improved performance, such as no overshoot and fast settling time, and the maximmum plant input is also effectively utilized.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.4
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• pp.58-65
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• 2005

A method measuring angular speed and estimating angular acceleration of an automotive wind shield wiper pivot with limited resources has been proposed. Limited resources refer to the fact that processes cannot be operated in real-time with a regular notebook running a Microsoft Windows. Also, they refer to the fact that data acquisition cards have only two general purpose counters as many generic cards do. An optical incremental encoder has been employed for measuring angular motion. To measure the angular speed of the pivot, periods for the encoder's output pulses have been measured as the speed is related to the reciprocal of the period. Since only information acquired from one counter channel is the magnitude of the angular speed, sign correction is necessary. Also the information for the exact time when a pivot passes left and right dead points is also missing and the situation is inherent to the hardware setup. To find out the zero-crossing time of the angular speed, a linear interpolation technique has been employed. Lastly, to overcome the imperfection of the mechanical encoders, the angular speed has been curve fitted to a spline. Angular acceleration can be obtained by a differentiation of the angular speed.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.21 no.47
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• pp.57-68
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• 1998

Work environments have been changed with the advent of new technologies, such as computer technology. However, human cognitive limits can't pace up with the change of work environment. Designing human-computer system requires knowledge and evaluation of the human cognitive processes which control information flow workload. Futhermore, under limited reaction time and/or urgent situation, human operator may the work stress, work error and resultant deleterious work environment. This paper evaluate the visual factors of major information processing factors(information density, amount of information, operational speed of speed)on operator performance of supervisory control under urgent(limited reaction time)environments which require deleterious work condition. To describe the work performance int the urgent work situations with time stress and dynamic event occurrence, a new concept of information density was introduced. For a series of experiments performed for this study, three independent variables(information amount, system proceeding speed, information density) were evaluated using five dependent variables. The result of statistical analyses indicate that the amount of information affected on all of five dependent measure. Number of failure and number of secondary task score were influenced by both amount of information and operational speed of system. However reaction time of secondary task were affected by both amount of information and information density. As a result, the deleterious factors for the performances seemed to be a scanning time to supervise each control panel. Consequently, a new display panel was suggest to reduce operator work load for scanning task showing better operator performance.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.43 no.2
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• pp.233-243
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• 1994

Generally, fuzzy PI controller that regulates the gains using fuzzy algorithm shows high performance in speed response. However, it has some problems to the load inertia variation, because the change of speed error(CE) is in a fixed range. As load inertia increases, CE is decreased and the usuage of fuzzy table is limited. Therefore, the output of the fuzzy controller has a limited range. This paper proposes an improved fuzzy PI controller. To reduce the speed overshoot, we adapt a control method that selects a proper CE range with respect to the load inertia variation. The proposed controller is applied to the vector controlled system with 2.2kW induction motor. Some simulation and experimental results are exhibited. With these results, we can easily find that proposed PI controller is more robust than the conventional fuzzy PI controller against the load inertia variation.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.45 no.1
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• pp.74-80
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• 1996

This paper describes current controlled PWM technique of PM synchronous motors for a wide variety of speed control applications. They are however limited in their ability to operate in the power limited regime where the available torque is reduced as the speed is increased above its base value. This paper reviews the operation of the PMSM drives when they are constrained to be within the permissible envelope of maximum inverter voltage and current to produce the rated power and to provide this with the highest attainable rotor speed. The optimal field-weakening control algorithm is the use of phase current and d-axis current feedback to reduce of error between the d-axis current command and real current and to improve the torque characteristics. The improved torque characteristics of speed control strategy with optimal field weakening control algorithm is analyzed and the performance is investigated by the computer simulation and experimental results. (author). refs., figs.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.588-590
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• 1994

This paper describes current controlled PWM technique of IPM synchronous motors for a wide variety of speed control applications. The IPM synchronous motors have a saliency, in which the q-axis inductance is larger than the d-axis inductance. As a consequence, there exists a reluctance torque component Thus when this component is added to the torque component produced by the stator currents and the air-gap flux, IPM motor drives are readily applicable where full torque Is required up to full or base speed. They are however limited in their ability to operate in the power limited regime where the available torque is reduced as the speed is increased above its base value. This paper reviews the operation of the IPMSM drives when they are constrained to be within the permissible envelope of maximum inverter voltage and current to produce the rated power and to provide this with the highest attainable rotor speed. The wide variety of speed control strategy is analyzed and the performance is investigated by the computer simulation using actual parameters of a drive system. Simulation results are given and discussed.

• Proceedings of the KSR Conference
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• 1999.11a
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• pp.376-384
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• 1999

In this paper, we introduce the on-line test plan of high speed rail development, which will be carried out at the test section of Seoul-Pusan high speed line from May to October, 2002. The test items are decided focused on the verification of the perofrmace and acquirement of the technical data of the high speed rail system development. The running time and distance of the train are calculated for several limited maximum speed cases. The detailed test scenario shall be developed according to the process of development and design of the system.