• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.4B no.2
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• pp.59-64
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• 2004

Study of an accurate and robust braking control method is required as a technical improvement to the servo system. In particular, the braker exhibiting constant braking performance under speed variation conditions of the prime mover needs to be investigated. In this paper, the braking torque of the eddy current braker between the electromagnet stator and rotating disk is analyzed. The torque-speed characteristics and accurate disk construction are represented. From the computer simulation results, it was found that eddy current braking torque is linear or approximately constant over the desired speed range depending on the rotor material, disk construction, pole number and pole displacement of the stator. These relations are confirmed by experimental results.

• Proceedings of the KIEE Conference
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• 2006.05a
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• pp.63-65
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• 2006

A electrical fault is defined as any abnormal condition caused by a reduction in the insulation strength. To define the potential risk of the electric installation, measurement of leakage current has been getting considered, but because the measured leakage current value also contained leakage current by capacitance, the measured value could not be adapted to absolute reference to the installation. Therefore, in this paper, the correlation between the condition of electric installation and leakage current were analyzed. The result focuses on to detect them in a cost efficient way.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.642-645
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• 2003

We proposed new current source and mirror circuits insensitive to $V_{th}$ variation of poly-Si TFTs. The proposed circuits have been verified by SPICE simulation using poly-Si TFT model. The error currents of the proposed current source and current mirror circuits caused by $V_{th}$ variation reduced less than 6.6% and 4.5% of that of conventional ones, respectively.

• Proceedings of the KIPE Conference
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• 2003.07b
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• pp.579-583
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• 2003

Hysteresis controllers are intrinsically robust to system parameters, exhibit very high dynamic response and are suitable for simple implementation. But the current control using a conventional hysteresis controller has the disadvantage that high switching frequency may happen due to lack of coordination among individual hysteresis controllers of three phases. This will of course increase the switching loss. In addition, the current error is not strictly limited. So, in this paper to reduce the switching frequency, a double band hysteresis current controller is proposed. The presented control system was tested with digital simulation in the Borland C++ program and demonstrate the advantage of proposed hysteresis current controller.

• Journal of Electrical Engineering and information Science
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• v.2 no.4
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• pp.86-91
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• 1997

A method of detecting the three phase currents for a voltage-fed pusle width modulated(PWM) inverter is proposed, where only one current sensor is utilized on the dc-link. The proposed method has the constant sampling time by employing he modified space-vector PWM technique which generates the rearranged switching pattern to detect a phase current from ad dc-link current. Experimental results show that eh proposed scheme provides a very good detection method of three phase currents without phase current sensors. This method is very simple and has small detection errors.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.252-254
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• 1994

This paper describes the control method in order that output current of a voltage source inverter tracks reference sinusoidal current so that its harmonic current components are reduced. Operating character of this inverter is analyzed with normalized values of parameter. And the method that apply multilayed feedfoeward neural networks, which play excellent steady state operation in control system, to inverter control system and training method are presented. Then, the output current of inverter which is driven by the proposed method. is considered throughout computer simulation and safe operating range of inverter parameter is resented.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.211-213
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• 1994

In tins paper, the method of analysis of induction heating is proposed. It's a coupled problem. First, eddy current problem with current source is analyzed using 2-D finite element method, from which eddy current distribution is obtained. And the second, heat source can be calculated directly by the eddy current. Also the temperature distribution is obtained using 2-D finite element method. Eddy current problem and heat transfer problem are dealt with under steady state in this paper.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.335-336
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• 2007

A new current-programmed pixel circuit for activematrix organic light emitting diodes (AMOLEDs), based on Organic TFTs (OTFTs), is proposed and verified by SPICE simulations. The simulation results show that the proposed pixel circuit, which is a current mirror structure consisting of five Organic TFTs and one capacitor, has reliable linear characteristics between input current and output OLED current. Also, the threshold voltage degradation of Organic TFTs due to long time operation stress is well compensated to reliable values.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.2
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• pp.171-176
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• 2013

Classically, reluctance torque of IPMSM(Interior Permanent Magnet Synchronous Motor) by using inductance according to current phase angle generates an error. This error is affected by total torque. From current phase angle $0^{\circ}$ to large errors will occur, because reluctance torque include current phase angle. But, reluctance torque from steady-state voltage equation of IPMSM is represented by linkage flux. So, reluctance torque is unrelated to the current phase angle formula can be derived. In this paper, operating torque was analyzed by d, q-axis linkage flux of IPMSM and reluctance torque to perform calculations reduced the error of the total torque calculation.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.36 no.5
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• pp.520-524
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• 2023

An algorithm was developed to detect and block serial arc currents using HPF. The AC series arc problem is that the load current is greater than the fault current and no leakage current occurs. As a solution, an arc detection method utilizing differences in high- frequency amplitudes was developed. HPT was applied to the load current and FFT was applied to eliminate low frequencies. An algorithm has been developed to detect arc waveforms when they exceed a certain value compared to the average of normal waveforms. Using one cycle of data, arc detection is faster and arc accidents are prevented.