• Proceedings of the KIEE Conference
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• 1989.07a
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• pp.40-43
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• 1989

In recent years, Levitated transportation systems have been studied in many countries, Most vehicles used for these systems are driven by linear motors and are levitated magnetically. The magnetic train HDMAG-01 is a proto-type vehicle for low-speed in the range of 100cm/S. This paper presents an outline of the drawing, the testing and its results, describes theoretical models used and compares between computer simulation and test result.

• Proceedings of the KIEE Conference
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• 1989.11a
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• pp.283-287
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• 1989

This paper presents a microprocesser based Self-Controller for a Permanent Magnet Synchronous Motor(PMSM), fed by voltage soure inverter. The proper operation of the PMSM can be ensured only if the stator current is always synchronized with the its Back-E.M.F. The use of incremantal encoder with high resolution makes it possible to design a Self-Control led P.W.M. inverter. The pulse ratios are controlled to reduce the torque ripple in the low-speed drive region. And during the operation, torque - speed characteristics are improved by the control of optimal load angle.

• Proceedings of the KIEE Conference
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• 1989.11a
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• pp.313-316
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• 1989

A steady state analysis of a load commutated current source inverter which is widely used in high voltage - high power induction motor drive systems at present is presented and its related results are discussed. This analysis proposes a method by which we can determine the output capacitor playing a dominant role on the performance of the system. It is shown that the capacitance of output capacitors is mainly dependent on the range of frequencies that the inverter is operated in the load commutated state.

• 전기의세계
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• v.28 no.3
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• pp.65-71
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• 1979

This paper examines the reasonable winding arrangements of designing tapped winding capacitor motors to used in two voltage sources. The approach of this paper is based partly on a hybrid equivalent circuit of a single phase induction motor, together with an experimental method by sample machines. In results, the distribution of etra and main windings ia the stator is to be balanced in each magnetic pole and in order to have the same torque output characteristics for two different voltage sources, the extra/main winding ratio is to be adjusted. Experimental results obtaired with sample macines of about 1/8 hp output rating are used with analysis to predict the favorable winding conditions.

• 전기의세계
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• v.24 no.1
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• pp.43-53
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• 1975

This paper describes a converter, which combines SCR bridge type rectifier circuit with a rotating distributor. This type of converter produces an adjustable low frequency output of three phase or single phase, from three phase or single phase power source. Output-waveforms of this converter are multi-pulse in three phase output, and square wave in single phase output. Problems about the operation of static switches, a commutation and output-waveforms are investigated, and experimental results verify that frequency can be adjusted satisfactorily from zero to 20 (Hz) and the expected output-waveforms are obtained without sparking on the distributor under various loading conditions. This converter can be utilized to low speed control of A.C. motors, and other lowfrequency loads.

• 전기의세계
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• v.24 no.1
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• pp.29-42
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• 1975

In this paper, the electrical angle between two winding axes in the stator of the capacitor motor is put optional angle, deviding the space harmonics in its magnetic field of two windings and the leakage flux into the forward revolving field and the backward one by the revolving-field theory, its equivalent circuit which consider mutual induction between two windings is depicted. In the depicted equivalent circuit, the rotor resistance for the fundamental flux is devided into the resistance for the rotor bar and endring, and the rotor leakage reactance for the fundamental is devided into the skew leadage reactance and the other, and each circuit constants for each harmonics is expressed in terms of the circuit constants for the fundamental, so it mades easy to determine the characteristics for the capacitor motor. As the circuit constant ratios to the magnetizing reactance of the fundamental are used, motors which have same circuit constant ratios should be resembled in their characteristics.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.55 no.9
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• pp.437-442
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• 2006

Cogging torque, the primary ripple component in the torque generated by permanent magnet (PM) motors, is due to the slotting on the stator or rotor. This article shows the reduction of cogging torque in a novel axial flux permanent magnet (AFPM) motor through the various design schemes. 3D finite element method is used for the exact magnetic field analysis. The effects of slot shapes and skewing of slot on the cogging torque and the average torque have been investigated in detail.

• 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.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.3B no.1
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• pp.59-64
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• 2003

This paper presents a new rotor position estimation method for brushless DC motors. The estimation error of the rotor position clearly provokes the phase shift angle misaligned between the phase current and the back-EMF waveforms, which causes torque ripple in brushless DC motor drives. Such an estimation error can be reduced with the help of the proposed neutral-voltage-based estimation method, which is structured as a closed loop observer. A neutral voltage appearing during the normal mode of the inverter operation is found to be an observable and control table measure, which can be used for estimating an exact rotor position. This neutral voltage is obtained from the DC-link current, the switching logic, and the motor speed values. The proposed algorithm, which can be easily implemented by using a single DC-link current and the motor terminal voltage sensors, is verified by simulation and experiment results.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.51 no.7
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• pp.351-356
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• 2002

The oil circulation rate (OCR) of the rotary compressor is a crucial factor affecting the performance and reliability of air-conditioning systems. In this paper, topology optimization of the single-phase induction motor of rotary compressor is carried out for reducing the OCR. The nonlinear transient characteristic of single-phase induction motor for rotary compressor is analyzed by using FLUX2D. The topology optimization for electromagnetic systems is developed using the finite element method (FEM). The topology optimization is applied to a single-phase induction motor for reducing the OCR. For validation, optimize induction motors are manufactured and tested.