• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.52-55
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• 1996

In order to establish the robust current controller design technique of series wound motor driver system. This paper proposes a method of compensated Bang-Bang current control using a series wound motor driver system under improperly variable load. To get minimum time torque control. A compensated Bang-Bang current controller structure is simpler than the structure of PID plus Bang-Bang controller. This paper shows that a general 8 bits microprocessor be used efficiently implementing such an algorithm. The calculation time of software is extremely small when compared with conventional PID plus Bang-Bang a controller. Both nonlinear operating characteristics of Digital switching elements and Describing Function methods are used for the analysis and synthesis. Real time implementation of compensated Bang-Bang current is achieved. Concept design strategy of the control and PWM waveform generation algorithms are presented in the paper.

• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.142-145
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• 2001

In this paper the electromagnetic torque developed in IPMSM(Interior Permanent Magnet Synchronous Motor) is analyzed. If flux distributions in the motor are not sinusoidal, a sinusoidal current produces important torque ripple. Torque ripple causes vibration and noise of motors. The optimized current waveforms for ripple free is able to be obtained by analysis of Back-EMF and torque equation. The method to find the optimal current is based on numerical predetermination. In this paper proposes current waveform which can eliminate the torque ripple, and the validity is verified through the simulation.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.11B no.4
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• pp.164-168
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• 2001

In this paper voltage source FEA for hysteresis motor considering magnetic hysteresis characteristics is presented. The Preisach model is used as a hysteresis model. System matrix whose unknown variables are vector potentials and currents is formulated for voltage source. The stiffness matrix is maintained constant by using M-iteration method. Therefore the calculation time and efforts are reduced with Choleski direct method. Current waveform can be calculated for arbitrary voltage vaveform considering hysteresis effects.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.33 no.6
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• pp.521-521
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• 2020

• Proceedings of the KIEE Conference
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• 2003.10b
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• pp.187-189
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• 2003

Conventional Switched Mode Power Supplies(SMPS) with diode-capacitor rectifier have distorted input current waveform with high harmonic content. Typically, these SMPS have a power factor lower than 0,65. To improve with this problem the power factor correction(PFC) circuit of power supplies has to be introduced. Specially. to the reduce size and manufacture cost of power conversion device, the single-stage PFC converter is increased to demand as necessary of study. in this paper, The comparative analysis of power factor correction circuit using Feedforward control with average current mode flyback converter(single-stage) and boost converter(two-stage). Also, the validity of designed and manufactured high power factor flyback converter and boost converter is confirmed by simulation and experimental results.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.924-926
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• 2001

This paper presents the characteristics of current harmonics and torque ripple of Brushless DC motor, which is developed the fan blower of vehicles, according to permanent magnet shape input voltage wave form. To investigate the torque ripple and the phase current harmonics, these characteristics is analysed and compared the experimental results. In the process of analysis, FEM is introduced and computed a transient state torque of BLDC with a sinusoidal and a PWM wave voltage.

• Proceedings of the KIEE Conference
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• summer
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• pp.1214-1216
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• 2004

Conventional Switched Mode Power Supplies(SMPS) with diode-capacitor rectifier have distorted input current waveform with high harmonic contents. Typically, these SMPS have a power factor lower than 0,65. To improve with this problem the power factor correction(PFC) circuit of power supplies has to be introduced. PFC circuit have tendency to be applied in new power supply designs. The input active power factor correction circuits can be implemented using either the two-stage or the single-stage approach. In this paper, the comparative analysis of power factor correction circuit using feedforward control with average current mode single-stage flyback method converter and two-stage converter which is combination of boost and flyback converter. The two prototypes of 50W were designed and tested a laboratory experimental. Also, the comparative analysis is confirmed by simulation and experimental results.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.744-746
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• 2003

This paper presents characteristics analysis of brushless DC motor(BLDCM) which is driven by four types of PWM mode. The Phase current, radial forte and torque ripples are generated differently at each PWM mode. So they have different influences on motor characteristics. In this paper, we analyzed characteristics of BLDCM using time-stepped voltage source finite element method. The effect of four types of PWM mode had been confirmed by comparing each phase current and torque ripple waveform. The compared simulation result is useful to select a better PWM mode.

• Journal of Welding and Joining
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• v.17 no.4
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• pp.85-92
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• 1999

In GMAW, the spatter is generated because of the variation of the arc state. If the arc state is quantitatively assessed, the control method to make the spatter be reduced is able to develop. This study was attempted to develop the optimal model that could estimate the arc state quantitatively. To do this, the generated spatters was captured under the limited welding conditions, and the waveforms of the arc voltage and of the welding current were collected. From the collected waveforms, the waveform factors and their standard deviations were produced, and the linear and non-linear regression models constituted using the factors and their standard deviations are proposed to estimate the arc state. the performance test to the proposed models was practiced. Obtained results are as follow. From the results of correlation analysis between the factors and the amount of the generated spatters, the standard deviations of the waveform factors have more the multiple regression coefficients than the waveform factors. Because the correlation coefficient between T and {TEX}$T_{a}${/TEX}, and s[T] and s[{TEX}$T_{a}${/TEX}] was nearly one, it was found that these factors have the same effect to the spatter generation. In the regression models to estimate the arc state, it was fond that the linear and the non linear models were also consisted of similar factors. In addition, the linear regression model was assessed the optimal model for estimating the arc state because the variance of data was narrow and multiple regression coefficient was highest among the models. But in the welding conditions which the amount of the generated spatters were small, it was found that the non linear regression model had better the estimation performance for the spatter generation than the linear.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.98-103
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• 2001

In case that electronic ballast employing a valley-fill passive power factor correction (PFC) circuit is used for feeding fluorescent lamps, a new method to reduce crest factor of the lamp current is studied in this paper. In order to reduce crest factor to lower value, a pulse frequency modulation technique based on the waveform of the dc-link voltage which is predetermined by the passive PFC circuit, is taken into the switching control action of the electronic ballast. An equation-based analysis between the crest factor of lamp current and the effect of varying the inverter switching frequency is comprehensively performed.