• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.2378-2381
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• 2003

In recent years, fuzzy logic has received greater emphasis in the field of power electronics and motion control by virtue of its adaptive capability. A new fuzzy logic based soft-start scheme for induction motor drives close to load detection has been discussed here using microcontroller based thyristorised voltage controller. Rule based soft-start algorithm is fully realised through a software approach only. The soft-start strategy is based on the change of input impedance during starting period. The prototype has been tested under various loading conditions and found to be reliable.

• Proceedings of the KIEE Conference
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• 1990.11a
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• pp.326-331
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• 1990

In the vector-controlled induction machine drive, mechanical sensors restrict the wide applications of high performance AC drives. So in resent years, many papers have been presented which doesn't need mechanical sensors, named by sensorless vector control. But sensorless control has a few serious problem, one of which Is poor speed estimation in case of incorrect rotor resistance (Rr) information. This paper describes the stator flux orientation speed control strategy with the speed estimation algorithm. and the method of adapting Rr change due to thermal heating. By proposed method. We can acquire precise speed estimation and higher performance.

• Proceedings of the KIEE Conference
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• 1997.07f
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• pp.2088-2090
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• 1997

This paper consists of the speed sensorless vector control of induction motors with the estimation of rotor resistance. In the application of variable-speed induction motor drives, if an inaccurate rotor resistance is used because the rotor resistance can change due to skin effects and temperature variables, it is difficult to achieve a collect field orientation. In this paper, to overcome these difficulties adaptive algorithm is designed for rotor resistance identification. The proposed adaptive algorithm for rotor resistance estimation in the synchronous reference frame is applied by sliding mode current controller satisfing persistent excitation(PE) condition. Adaptive flux observer is here used for the purpose of estimating rotor flux and speed in the speed sensorless scheme. Computer simulations are carried out to verify the validity of the proposed algorithm.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.510-513
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• 1996

This paper consists of the speed sensorless vector control of induction motors with the estimation of rotor resistance. In the application of variable-speed induction motor drives, if an inaccurate rotor resistance is used because the rotor resistance can change due to skin effects and temperature variables, it is difficult to achieve a collect field orientation. In this paper, to overcome these difficulties adaptive algorithm is designed for rotor resistance identification at the beginning of the transient state. And an adaptive flux observer is used for the purpose of estimating rotor flux and speed in the speed sensorless scheme. Computer simulations are carried out to verity the validity of the proposed algorithm.

• Journal of KSNVE
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• v.11 no.3
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• pp.471-476
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• 2001

This paper focuses on the numerical prediction of airflow-induced sound in DVD drives. As a first step, computational fluid dynamics (CFD) is conducted to evaluate flow field characteristics due to the high-speed disk rotation, and to support the acoustic analysis. Acoustic analogy based on Ffowcs Wi1liams-Hawkings (FW-H) equation is adopted to predict aeroacoustic noise patterns. The integral solution for quadrupole volume source is included to identify the turbulence noise generated inside the DVD tray. The strength of sound pressure revel with respect to rotating speed is discussed to meet upfront demand on the high fidelity product development. The present study also focuses on the noise directivity and examines how much the sound noise is sensitive to change in rotating speed. Near-field noise is strongly affected by the flow field characteristic, which is caused by the complex shape of the tray. For a mid-field, the quadrupole noise play as a counterpart of thickness noise or loading noise, so it generates different sound noise Patterns compared with those in the near field.

• Journal of Power Electronics
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• v.8 no.3
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• pp.210-216
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• 2008

This paper presents a classical speed controller (CSC) for vector controlled induction motors. The controller explores the use of a Fuzzy Logic controller in a classical form. The controller combines the advantages of the classical controller and the properties of intelligent controllers. The Fuzzy Logic controller idea is used to obtain the CSC output equation, whereby the CSC equation is based on the speed error and its change. The CSC parameters are calculated based on the motor mechanical equation and a predefined system performance. Once the CSC parameters are obtained, the defined speed performance can be achieved at all operating conditions. The application of the CSC to control the speed of a vector controlled induction motor is presented. Different induction motor ratings are used. Simulation results in all possible olperating conditions are presented. Results show that the CSC behaves as an expert controller to provide the predefined speed performance in all possible operating conditions. Based on the results obtained in this paper, the CSC is expected to become the ultimate solution for high-performance drives of the next generation.

• Proceedings of the KIPE Conference
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• 2004.07a
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• pp.312-315
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• 2004

This paper presents a tuning-free conditional integration anti-windup strategy for induction machine with Proportional-Integral (PI) type speed controller. The on/off condition of integral action is determined by the frequency domain analysis of machine torque command without a prior knowledge of set-point changes. There are no tuning parameters to be selected by users for anti-windup scheme. In addition, the dynamic performance of the proposed scheme assures a desired tracking response curve with minimal oscillation and settling time even in the change of operating conditions. This algorithm is useful in many high performance induction machine applications not to allow the oscillation and overshoot of speed/torque responses. The main idea can be extended to general applications such as chemical processes and industrial robots.

• Proceedings of the KIPE Conference
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• 2003.11a
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• pp.11-16
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• 2003

The 3-level converter/inverter system is very efficient in the ac motor drives of high voltage and high power application. This paper proposed a simple method to diagnose faults using change of current vector pattern in space vector diagram when the faults occurrence in the 3-level inverter and a control method that can protect system from unbalance of the neutral point voltage according to faults. The validity of the proposed method is demonstrated by the simulation results.

• Proceedings of the KIEE Conference
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• 2002.04a
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• pp.79-81
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• 2002

This paper develops a adaptive fuzzy controller based fuzzy logic control for high performance speed controller in permanent magnet synchronous motor(PMSM) drives. In the proposed system, fuzzy control is used to implement the direct controller as well as the adaptation mechanism. The operation of the direct fuzzy controller and the fuzzy logic based adaptation mechanism is studied. A model reference adaptive scheme is proposed in which the adaptation mechanism is executed by fuzzy logic based on the error and change of error measured between the motor speed and output of a reference model. The control performance of the adaptive fuzzy controller is evaluated by simulation for various operating conditions. The validity of the proposed adaptive fuzzy controller is confirmed by performance results for PMSM drive system.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.55 no.7
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• pp.373-379
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• 2006

The low-voltage induction motors have been widely driven by IGBT PWM inverters, ever since it was used to apply variable speed drives. Recently, the insulation failures of the stator windings become critical problems due to the high ratio of dv/dt in IGBT PWM inverters. In this paper, the detailed insulation tests on the IGBT PWM inverter fed induction motor are carried out. Five different types of insulation techniques are used to ti induction motors. The change of the insulation characteristics such as partial discharge, AC current, capacitance, and dissipation factor are compared. respectively In addition, insulation breakdown tests using the high voltage pulse are performed, and corresponding breakdown voltages are analyzed.