• The Transactions of the Korean Institute of Electrical Engineers
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• v.34 no.2
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• pp.47-55
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• 1985

In this paper, a multiple pulse-width modulated ac chopper mode power controller using power transistor is described. The controller is capable of handling up to 1/2 hp of power at any lagging load power factor angle and getting the optimal efficiency operating characteristics. The development, study, and experimental evaluation of the controller with induction motor load is described.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.46-48
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• 1997

Induction motor control using for adjustable speed drives has caused secondary effect such as harmonics. Therefore it is considered a various countermeasures to minimize these effects. In this paper, we analyzed the influence of harmonics that is generated by the inverter device for adjustable speed drive of induction motor at the load side.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.179-182
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• 2002

This Paper described a robust control of an induction motor using a disturbance cancellation observer of a feedforward control, The speed response of conventional Pl controller characteristic is affected by variations of load torque disturbance. Tn the proposed system, the speed control characteristic using a feedforward control isn't affected by a load torque disturbance.

• Proceedings of the KIPE Conference
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• 2003.07b
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• pp.816-819
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• 2003

This paper described a robust control of an induction motor using a disturbance cancellation observer of a feedforward control with Matlab simulink. The speed response of conventional PI controller characteristics is affected by variation of load torque disturbance. In this system, the speed control characteristics using a feedforward control toughen about a load torque disturbance.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.31 no.8
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• pp.46-53
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• 1982

When an induction motor is lightly loaded, the efficiency can be very substantially improved by controlling the air gap flux. Thus in the system which requires constant speed under either normal load or light load, it is possible to save energy by means of controlling the air gap flux. In this paper, the required relationships between stator current and rotor slip frequency for optimal efficiency control is derived and the improved control loop is suggested.

• The Transactions of the Korean Institute of Power Electronics
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• v.11 no.1
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• pp.38-45
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• 2006

This paper presents load torque observer that is used to deadbeat control method in the induction motor(IM) precision position control system. The proposed algorithm shows robustness on induction servo motor system. All of the gain has been obtained on discrete domain analysis. The simulation has been obtained by the simulink. The results show that proposed system has good effectiveness for the disturbance of the induction servo motor system using DS1102 board.

• The Transactions of the Korean Institute of Power Electronics
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• v.21 no.1
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• pp.65-71
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• 2016

This study investigates a high-accuracy alternate QD model to estimate the characteristics of induction motor under light loads. To demonstrate the usefulness of the alternate QD model, a maximum torque per amp (MTPA) control based on the alternate model is shown to outperform MTPA control based on the standard QD model. The experimental study conducted in this work exhibits that the MTPA control based on the alternate QD model tracks torque commands between 20 Nm and 30 Nm with 5% error, whereas the MTPA control based on the standard QD model generates torques lower by over 23% compared with the aforementioned torque commands. This result indicates that the alternate QD model is a highly accurate model for induction motors under light loads.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.10a
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• pp.18-23
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• 2002

In this paper, The torque of CNC spindle motor during machining is estimated without speed measuring sensor. The CNC spindle system is divided into two parts, the induction spindle motor part and mechanical part. In mechanical part the variation of the frictional force due to the increment of the cutting torque and the effect of damping coefficient is investigated. Damping coefficient is found to be a function of spindle speed and not influenced by the weight of the load, while frictional force is a function of both the cutting torque and spindle speed. Experimental formulars are drawn for damping coefficient as a function of spindle speed and frictional force as a function of both cutting torque and spindle speed respectively, to estimate the cutting torque accurately. Graphical programming is used to implement the suggested algorithm, to monitor the torque of an induction motor in real time. Torque of the spindle induction motor is well monitored with 3% error range under various cutting conditions.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.6
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• pp.513-518
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• 2007

In this paper, we propose a fault diagnosis scheme tor induction motor by adopting a hierarchical classifier consisting of k-Nearest Neighbors(k-NN) and Support Vector Machine(SVM). First, some motor conditions are classified by a simple k-NN classifier in advance. And then, more complicated classes are distinguished by SVM. To obtain the normal and fault data, we established an experimental unit with induction motor system and data acquisition module. Feature extraction is performed by Principal Component Analysis(PCA). To show its effectiveness, the proposed fault diagnostic system has been intensively tested with various data acquired under the different electrical and mechanical faults with varying load.

• Journal of Electrical Engineering and Technology
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• v.6 no.5
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• pp.666-670
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• 2011

In this paper, a method for detecting broken rotor bar and stator winding fault in a low voltage squirrel-case induction motor using an air-gap flux variation analysis is proposed to develop a simple and low cost diagnosis technique. To measure the leakage flux in radial direction, a radial flux sensor is designed as a search coil and installed between stator slots. The proposed method is able to identify two kinds of motor faults by calculating load condition of motors and monitoring abnormal signals those are related with motor faults. Experimental results obtained on 7.5kW three-phase squirrel-cage induction motors are discussed to verify the performance of the proposed method.