• Proceedings of the KIPE Conference
• /
• 1998.10a
• /
• pp.125-130
• /
• 1998

This paper presents a speed control for ultrasonic motors using a PI controller and disturbance torque observer. Since the PI gains and the observer's poles are generally fixed, the control performance deteriorates when the driving conditions vary much. Therefore, we propose the speed control scheme that the PI gains and the observer's poles are adjusted on-line in accordance with the speed ripple using fuzzy reasoning.

• Proceedings of the KIPE Conference
• /
• 1998.07a
• /
• pp.337-341
• /
• 1998

Brushless DC motors have trapezoidal back emf waveform. Generally, because it is drived by a voltage source inverter, the ideal rectangular phase current is not available and therefore produce torque ripple. In this paper, the torque ripple due to commutation is analysed and the practical method that can reduce the torque ripple is proposed. Simulation and experimental results show the effectiveness of the proposed method.

• Proceedings of the KIPE Conference
• /
• 1998.10a
• /
• pp.488-492
• /
• 1998

Indirect sensing of the rotor position of permanent magnet brushless DC motors contains position error. Such measuring error can be attenuated by adopting Kalman filter. In this paper, the cause of measuring error is analyzed and the design technique of Kalman filter is described. Experimental results show that the proposed sensorless drive exerts superior performances.

• Proceedings of the Korean Institute of Resources Recycling Conference
• /
• 2004.05a
• /
• pp.114-118
• /
• 2004

• Proceedings of the KIEE Conference
• /
• 2002.11d
• /
• pp.27-29
• /
• 2002

In this paper, we deals with a torque measurement method of micro motors having very small torque values. The commercial motor torque dynamometers are examined, and the performance of a prototype microtorque measurement system is investigated.

• Proceedings of the KIEE Conference
• /
• 1987.11a
• /
• pp.139-142
• /
• 1987

It is important to evaluate the voltage characteristics of diesel generator as an emergency power supply in nuclear power plant. On loss of offsite power sources, emergency safeguard loads required to safely shutdown the reactor should be supplied by diesel generator. This paper presents the dynamic stability program to evaluate diesel generator performance as an emergency power system. The results Indicate the diesel generator ability to start the motors successfully seems to life in its impedances and inertias.

• Proceedings of the KIPE Conference
• /
• 2013.07a
• /
• pp.269-270
• /
• 2013

This paper proposes the estimation algorithm to find the rotor time constant of induction motors, which is very important for induction motor drive system. This strategy is based on flux estimator theory. Proposed method has been demonstrated through simulation using MATLAB SIMULINK.

• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.43 no.4
• /
• pp.586-593
• /
• 1994

This paper suggests the algorithm for on-line efficiency control of permancent magnet synchronous motors driving the electric vehicles. The existance of unigue d-axis current is verified, which generates the maximum efficiency at operating points of motor. Using the Fibonacci search method, d-axis current converges to the minimization of inverter input power, and to prevent the variation of motor speed in process of the efficiency control, the voltage decoupled control strategy is introduced. Through the experiments, the effects of an efficiency control algorithm are verified.

• Proceedings of the KIEE Conference
• /
• 2000.07b
• /
• pp.906-908
• /
• 2000

This paper presents dynamic modeling and simulation of induction motors. Equivalent circuit parameters measured by do test, no-load test and locked-rotor test were used as the input data for computer simulation. Operating characteristics of an induction motor were predicted by Matlab/simulink when changing load torque, opening and reclosing of phase a of the stator and three-phase fault at machine terminals.

• Proceedings of the KIEE Conference
• /
• 1999.07a
• /
• pp.324-326
• /
• 1999

For induction motors cannot maintain constant speed in various speed conditions, synchronous motors are generally used. But synchronous motor oscillate in shocking load, and it cannot start by itself for the lack of starting torque. In this paper, we analyzed the synchronous induction motor which has both characteristics, and compared the experimental results with FEM analysis.