• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.660-662
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• 2001

This paper describes the problems generated with the use of PWM ASDs with induction motors. The major effect of harmonic voltages and currents in induction motors is increased the heating due to iron and copper losses at harmonic frequencies. The harmonic components thus affect the motor efficiency and developed the torque. In order to investigate the effect of harmonics which is caused by using of nonlinear load at the low voltage system, we set up simple load system and measured the voltage and current. Measurement results show that additional operation of induction motor at the parallel bus in using nonlinear load such as ASD is helpful to the reduction of harmonic current.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.849-851
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• 2001

This paper presents experimental method of parameter measurement and starting characteristics of 3 phase induction motor. Equivalent circuit parameters measured by DC test, the blocked rotor test, and no load test were used as the input data for computer simulation. Starting characteristics, such as starting current and torque were analyzed through computer simulation by Matlab, and the simulation results were compared with experiment using strain gauge attached on motor shaft. We conform that experimental results are very similar to that of simulation.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.3
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• pp.116-123
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• 2003

This paper deals with an experimental study for on-line monitoring the performance of a universal motor for vacuum cleaner. Performance tests are conducted on the PC-based virtual instrumentation system designed using the graphical programming language LabVIEW. The proposed monitoring system is capable of performing real time measurement functions, including data acquisition, display, and analyses in the time and frequency domains, as well as data archiving. The measured mechanical and iron loss, voltage, current, input power, power factor, torque, and efficiency characteristics are presented as function of speed.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.6
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• pp.948-954
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• 2008

Now, but task for stringing trolley wire is worked manually by a measurement of dip, we need to development the automatic control system for a safety and effective tasks. In this paper, in works of stringing trolley wire by a mobile of robot, a method is proposed tension control for the stringing trolley wire. On the basics of a wire model with hard nonlinear, ac servo motor model for torque generating and stringing wire tension, the tension control scheme is design and implemented with a detected wire tension by a load cell. We experimentally show that the performance of the tension response are satisfactory to regulator tension. The proposed system is simulated and experimented, results is verified the utilities.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2008.05a
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• pp.231-234
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• 2008

The permanent magnet BLDC motors are increasingly being used in high performance applications due to the high torque density and simplicity in their control. In this paper, the control system of the BLDC motor is developed which can be used for the micro motor handpiece, and position sensorless control is realized using back EMF measurement scheme, The validity and practical applications of the developed slotless BLDC motor and drive system are verified through the experimental results.

• Journal of Advanced Marine Engineering and Technology
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• v.24 no.6
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• pp.102-109
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• 2000

In this industrial induction motor speed and torque controlled drive system, the closed loop control usually requires the measurement of speed or position of amotor. However a sensorless drive of an induction motor has several advantages ; low cost and mechanical simplicity. Thus this paper investigates a field oriented control method without speed and flux sensors. The proposed control strategy is based on the Model Reference Adaptive System(MRAS) using a new flux estimator which replaces integrators with two lag circuits as the reference model. This algorithm may overcome several shortages of conventional MRAS such as integrator problems, small EMF at low speed. The simulation and experimental results indicate good speed responses.

• Proceedings of the KIEE Conference
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• 1999.11b
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• pp.73-75
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• 1999

The performance of a SRM in terms of torque and power factor depends on the two-axis inductances (Ld and Lq) and iron loss of the machine. Finite element method has been used to determine these parameters for a motor with segmented rotor structure. Fock and Hart Method has been conducted to compare to verify the accuracy of proposed analysis method.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.8
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• pp.183-192
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• 1998

In this paper, we measure the back-EMF and the thrust of a linear brushless DC motor along the relative position between coils and magnets in various speed environments in order to obtain the back-EMF and the thrust as a function of a motor position. The measured back-EMF function and thrust function of the position differ from the analytical ones within 5%. The measured back-EMF and thrust function can, then, be employed in controlling the thrust ripple of the linear motor. Furthermore, to minimize the torque ripple of the linear motor, we suggest the design method to shape the back-EMF and thrust function of the linear motor.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.419-424
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• 1996

As track density increases, the effects of nonlinearity in pivot bearing of hard disk drive on the servo performance are becoming more important in considering the range of inertia force and the input torque during settling and tracking mode. Recently, an increasing attention is given to more precise experimental observations and modelings of pivot nonlinearity for achieving higher performance of servo control. In this paper, we propose a new model that shows an improved prediction of the pivot nonlinearity than existing preload-plus-two-slope model at matching simulations and experimental results in both time and frequency domains. Experimental measurements are carried out to validate and identify the specific nonlinearity presents in the pivot bearing when its in fine motion. Using the experimental results new model along with the existing one are characterized and compared for relevancies.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.36.2-36.2
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• 2011

In variable-speed variable-pitch wind turbines, the conventional approach for controlling power-production operation relies on a generator-torque controller and a rotor-collective blade-pitch controller. Both controllers use the generator speed measurement as the sole feedback input. In order to mitigate unwanted excitation of the control system, many filters are adopted. In this study, the characteristics of some filters for signal processing are investigated based on frequency response function. They include low-pass filters, band-pass filters, and notch filters. Especially, this study focuses on design parameters of their filters.