• Journal of the Korean Society for Precision Engineering
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• v.15 no.8
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• pp.60-70
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• 1998

A harmonic drive is compact torque transmission device with no backlash which is widely applied in industrial field to transmit torque precisely. However, one of the disadvantages of harmonic drives is the existence of mechanical flexibility caused by its structural properties, which imposes great limitation on designing precise controller This paper proposes a nonlinear controller for synchronous operation of DC servo-motors with harmonic drive, using Integrator Backstepping method. Furthermore, an alternative algorithm for serial type synchronous operation of multiple DC servo-motors is proposed. Simulation results by SIMULINK for proposed controller shows considerably small error and rapid approach to reference input, which can be adapted to industrial applications.

• Proceedings of the KIEE Conference
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• 1990.07a
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• pp.113-120
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• 1990

This paper presents a new aggregation method of induction motors for the load flow and transient stability analysis. The proposed method aggregates a group of motors into a single motor considering the variations of the system voltage and frequency so that the aggregated model represents the dynamic characteristics of the system accurately. The performance of the Method is shown by numerical simulation and is compared with that of LOADSYN algorithm.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.549-555
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• 2003

The technology of machine condition monitoring is used effectively to detect the machine faults at an early stage using different machine quantities, such as current, voltage, temperature and vibration. Induction motors are most widely used to drive pumps, compressors and fans in industrial drives. This paper presents approach to data fusion using Dempster-Shafer theory because only one technique has uncertainty. So we can obtain advanced accuracy of the machine fault diagnosis. Vibration and current quantities are applied to diagnose three-phase induction motor.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.3
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• pp.29-34
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• 2009

Diesel particulate filter (DPF) has been developed to optimize engine out emission, especially particulate matter (PM). One of the main important factors for developing the DPF is estimation of soot mass being accumulated inside the DPF. Evaluation of pressure drop over the DPF is a simple way to estimate the accumulated soot mass but its accuracy is known to be limited to certain vehicle operating conditions. The method to compensate drawback is adoption of integrating time history of the engine out PM and burning soot. Present study demonstrates current status of the soot estimation methods including the results from the engine test benches and vehicles.

• Proceedings of the KIEE Conference
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• 1998.07e
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• pp.1731-1733
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• 1998

This report is the first intermediate report of a series of field test result of large high voltage motors. Major specimens were 3.3/6.6kV class pump motor that was installed and operated for public water service by KOWACO(KOrea WAter resources COperation). The capacity of specimen motors were in range of several hundred kVA. Until now, we get the 22 field test result by testing technique discribed in IEEE standards and discharge-map technique reported by Japanese engineers. The test result were varied very wide range, and there was a tendency according to insulation material and manufacture.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.05c
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• pp.110-113
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• 2001

In this paper, vibration mode of Windmill type Ultrasonic Motors was analysed. We used the ANSYS program to analysis by FEM. Vibration Mode express 20 modes as each resonance frequency. We bind nearly same modes and compress 5 modes. Windmill type Ultrasonic Motor's rotation is generated the friction of rotor at top endcap. Thus, We will find the best driving frequency that generating large friction at top endcap.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.303-306
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• 1994

This paper presents a new rotor resistance identification algorithm for induction motors. The algorithm is derived form the fact that the slip frequency given in the d-q rotating frame is equal to that measured in the x-y fixed frame. Rotor resistance varies greatly with the machine temperature. In certain cases, the rotor resistance can increase 100 % over its ambient or nominal value. This deteriorates the dynamic performance of vector control systems for induction motors. However, the control scheme proposed in this paper is robust with respect to variations in rotor resistance because an efficient identification algorithm for rotor resistance is employed. To illuminate the performance of the proposed controller further, the simulation results are presented.

• Proceedings of the KIPE Conference
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• 2004.11a
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• pp.27-31
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• 2004

This paper presents a nonconventional method for oft starting of three-phase induction motors, which achieved by flux weakening technique. flux weakening is not done by reducing the applied voltage as in the conventional methods, Flus weakening is achieved y increasing the supply frequency over the rated value while the voltage amplitude is kept constant. This method has advantage of reducing the stress on the electrical and mechanical systems. The feasibility of this basic idea has been confirmed through investigating the starting transient corresponding to this mode of operation. For this purpose, a rigorous state space mathematical model has been developed and simulated. The validity of the proposed method through the results from the mathematical model have been confirmed experimentally.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.688-694
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• 2009

As a drive system for next generation train, we have been making research and development of a direct drive traction motor system without the conventional reduction gear. This traction motor is expected to have many advantages such as low noise, reduced maintenance, and energy saving. Due to the demand for high-output motors in the limited space between the wheels, open-ventilating traction motors with gear box have been widely used for many years. However, a conventional open-ventilating traction motor is necessary periodical disassembly to remove the accumulated dust from open-air ventilation. Reducing this burden, as well as increasing energy efficiency and reducing noise, would benefit the next generation of traction motors. To address these needs, KRRI have been developing a fully enclosed type direct drive motor(DDM) with high-efficiency permanent magnet for the next generation train.

• Journal of Magnetics
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• v.21 no.1
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• pp.72-77
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• 2016

Although the initial cost of permanent-magnet linear synchronous motors is high owing to the installation of armatures over the full length of the transportation lines, linear motors are useful for transportation systems because of their high speed, acceleration, and deceleration. For these reasons, research into reducing the cost of linear motors is necessary, and a stationary distributed-armature system has been suggested for installing armatures in sections where acceleration and deceleration of the mover are required. However, each armature has ends that significantly increase the cogging force, resulting in the increase in the thrust ripple of the mover. Therefore, in order to improve the thrust ripple of the system, the present study aims to provide auxiliary teeth on both ends of the armature to achieve an optimal design through an analysis of the contribution ratio with respect to factors regarding the design of the experiment and the objective function.