• 전기의세계
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• v.21 no.2
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• pp.9-19
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• 1972

The transient characteristics of separately excited d-c motor driven by thyristor d-c chopper is studied in this paper. The armature controlled system is applied. As a result of theoretrical analysis the following conculsions were drawn: (1) For the transient analysis, it is recognized that the state transition analysis is a more general method and powerful tool than the state equation method or signal flow graph method, although it includes iterative matrix calculations. And the system is dealt with a finite width sampled-data system in the state transition analysis. (2) The transient characteristics of the motor angular velocity and its torque to the sampling duration variation are compared with those due to the amplitude variation of d-c chopper voltage as follows. The attenuation rate of the transient characteristics is equal in both cases, but the initial value of the transient characteristics in former case is greater than in latter case. (3) The roots of characteristics equation of the system lie inside the unit circle of the Z-plane. Therefor the system is stable. Further it is found that as the sampling duration is decreased the relative stability is lessened.

• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.450-451
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• 2010

In this paper, the low-cost drive circuit of dc motor for a multipurpose small-size electric vehicle is developed. In order to change smoothly the rotating direction of dc motor for traction, the operating sequence of both the field current and the armature voltage according to the angle of a pedal of vehicle is suggested. The simulation study is carrier out to verify the proposed method, and the control system is implemented with 8-bit AVR.

• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.25-29
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• 2001

The BLDCM (Brushless DC Motor) characterized by linear torque to current, and speed to voltage has low acoustic noise, and fast dynamic response. Moreover, it has high power density with high proportion of torque to inertia in spite of small size drive. But, it produce torque ripple due to the motor inductance components in stator windings and back-EMF, when armature current is commutated. Therefore, it is difficult to apply the BLDCM to a precision servo drive system. In this paper is proposed to a new current control algorithm with using fourier series coefficients can minimize torque ripple due to the phase current commutation of BLDCM. Simulation and Experimental results prove the effectiveness the proposed algorithm through comparison with the conventional used unipolar PWM method.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.11a
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• pp.95-99
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• 2005

This paper presents a general proposal to design and calculate the performance of a tubular permanent magnet linear generator treated here on the basis of the Finite Element Method. Optimizing the linear generator dimensions reduces the cogging force, which occurs due to the interaction between stator teeth and the permanent magnets. The generated AC voltage is analyzed and evaluated for both no load and load cases to take the armature reaction effects on the air gap flux density. A repetitive routine is followed to calculate the output AC voltage from the change of flux and the speed of the single-phase linear generator. The AC output voltage is calculated for different resistive loads, and hence, the linear generator load characteristic is obtained. The designed linear generator is capable to generate an output power of 5.3kW with AC output voltage of 222V with an efficiency of 96.8% at full load of 23.8A. The full load current is chosen based on the thermal properties of the coil wire insulations.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10a
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• pp.670-674
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• 1992

This paper presents a velocity regulation scheme for a DC motor subjected to random torque and velocity measurement noises of white noise type as well as unknown constant load torque (bias). The scheme separately estimates an unknown bias in addition to state estimation by the bias-free Kalman Filter, and reflects the effect of the bias estimate to the armature input voltage such that velocity variations be regulated. It is shown via computer simulations that the performance of the present scheme is superior to that of the conventional analog PI regulator.

• Proceedings of the KIEE Conference
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• 1999.11d
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• pp.950-952
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• 1999

In this paper, we are studied a electrical properties study with P.D.GEORGE/STER LING Co. P.B 302-LV-2 POLYBUTADIENE RESIN which is used for VPI(Vacuum Pressure Impregnation)processing of field magnet and armature of traction motor in Korean national railroad at present was carried out its FT-IR (Fourier Transform Infra-Red) volume resistivity characteristics. The varnishes were experimented with the temperature range form $25[^{\circ}C]$ to $180[^{\circ}C]$ and applied voltage were supplied at 100, 250, 500, 1,000[V]. In this condition, the volume resistivity for specimens were measured. From the above study, the following data obtained for volume resistivity. It can be confirmed that velume resistivity with the increase of temperature is lower rapidly from room temperature to $130[^{\circ}C]$, and it is lower slowly at temperature higher than $130[^{\circ}C]$. Volume resistivity value is higher, according as the specimen is thick gradually. As the applied voltage is higher in the same temperature, volume resistivity value is lower.

• Proceedings of the KIEE Conference
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• 1999.07a
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• pp.232-234
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• 1999

A 30kVA superconducting generator (S.G.) has been designed, developed and successfully tested in KERI before the end of last year. The design is based on 2-dimensional electromagnetic field analysis of cylindrical coordinate. The field winding of rotor has been wound with superconducting wire of Nb-Ti alloy and tested after assembled with other rotor components. The stator has air-gap type armature windings which allow higher terminal voltage and more sinusoidal voltage waveform than conventional iron cored machines. Steady-state open & short-circuit test and lamp load test have been conducted also. The results of tests are given in this paper and compared with design quantities. Moreover the cooling scheme and characteristics of test system is included.

• Proceedings of the KIEE Conference
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• summer
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• pp.1118-1120
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• 2004

For the first time in Korea, a 100hp high Tc superconducting(HTS) motor has been designed, developed and successfully tested recently. The design was based on 2-dimensional electromagnetic field analysis of cylindrical coordinate. The field winding of rotor was wound with Bi-2223 tapes and tested after assembled with other rotor components. The stator had air-gap type armature windings which allow higher terminal voltage and more sinusoidal voltage waveform than conventional iron cored machines. Steady state open & short-circuit test and resistive load test were conducted also in generator mode. The fabrication and test results of this machine were discussed in this paper.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.11
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• pp.1634-1640
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• 2012

This paper develops the high-efficiency drive system of the small-size electric vehicles (EVs) driven by the brushed dc motors. A power circuit for driving the dc motor is designed with the H-bridge circuit and buck converter by considering both the efficiency and cost. In order to change smoothly the rotating direction of dc motor driven by the proposed power circuit, an operating sequence for both the field current and the armature voltage according to an accelerator pedal angle is suggested. Through the simulation studies and experimental results with the low-cost 8-bit AVR, the performances of the proposed methods are verified.

• Proceedings of the KIEE Conference
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• 1999.11b
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• pp.24-26
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• 1999

In this paper, the conceptual design and FE analysis results of salient pole type alternator under no load condition are described. The designed alternator's rating is 180kW, 3-phase, 4pole, 380/220V, 0.8pf, 60Hz. The conceptual design is described by the process of designing the armature, field, and obtaining some of equivalent circuit parameters. The comparison of FE analysis to the designed results of alternator's output voltage value shows a good agreement.