• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.32 no.3
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• pp.241-245
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• 2019

This work presents the response characteristics of a ZnO varistor to conductive EMP. An E1 pulse, standardized to MIL-STD-188-125-1, was applied to the varistors wherein the residual current and response times were measured with the applied E1 pulse current. Additionally, the response time was measured according to the length of the connection path. Consequently, the amplitude of the residual voltage through the ZnO varistors was increased with increasing amplitude of the applied E1 pulse current. As the length of the connection path increased, the operating response time and residual peak voltage also increased. These results indicate that the response characteristics of ZnO varistors can be applied to basic data to support the use of varistors as a protective measure against conductive EMP.

• The Transactions of the Korean Institute of Power Electronics
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• v.24 no.2
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• pp.134-137
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• 2019

A wide-bandwidth current controller is required for fast charging/discharging of super capacitor applications. Peak current mode is generally used to accomplish fast charging/discharging because this mode has fast response characteristics. However, the peak current mode control must have a slope compensation function to restrain sub-harmonics oscillation. The slope must be changed accordingly if the controlled output voltage is varied. However, changing the slope for every changed output voltage is not easy. The other solution, selecting the slope as the maximum value, causes a slow response problem to occur. Therefore, we propose a hybrid mode controller that uses a peak current and a newly specified valley current. Through the proposed hybrid mode control, the sub-harmonic oscillation does not occur when the duty is larger than 0.5 because of the fast response.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.5
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• pp.959-964
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• 2018

In this paper, it was firstly confirmed that the drain current of the depleted SOI MOSFET operated in the high frequency response delay occurs by the inductive parasitic. Depleted SOI MOSFET cannot be applied as a conventional high-frequency MOSFET model because the response delay of the drain current is generated in accordance with the drain voltage fluctuation. This response delay may be described as a non-quasi-static effect, and the SOI MOSFET generated the response delay by the inductive parasitics compared to typical MOSFET. It is confirmed that depleted SOI MOSFET's RF characteristics can be well reproduced with the proposed method including the drain current response delay.

• The Transactions of the Korean Institute of Power Electronics
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• v.23 no.2
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• pp.147-151
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• 2018

Phase-shift fullbridge (PSFB) converter detects the current in the primary side for operation of the peak current mode controller (PCMC). The PCMC must used the slope compensation to solve the problem when the effective duty is over 0.5. The voltage response of PSFB converters has slower than that of buck converter because of slew interval even if the voltage controllers of two converters have same bandwidth. To overcome these problems, this work proposes a compensating method of current reference considering slew interval and fast response in the PSFB converter. The effectiveness of the proposed method is proven using the PSIM simulation and experiment.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1445_1446
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• 2009

This paper represents the step response characteristics of shunts for impulse current. This work is aimed at the development of the reference measuring system(RMS) for impulse current rated 10 kA at 1/$20{\mu}s$, 100 kA at 4/$10{\mu}s$, 20 kA at 8/$20{\mu}s$, 40 kA at 30/$80{\mu}s$. According to the IEC 60060-2, the step response characteristics was assessed. As results of the test, the step response characteristics of newly developed shunts for impulse current satisfied requirements of RMS.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.10
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• pp.1648-1654
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• 2016

This paper analyzes complex vector current control for the enhanced cross-coupling compensation in accordance with parameter variation in grid-connected inverter system, and verifies through simulation and experiment. Complex vector current control is performed in the synchronous reference frame through d-q transformation. It generates cross-coupling components with rotating nominal angular frequency. In general, cross-coupling elements are compensated by decoupling terms added to output of conventional decoupling PI controller. But, it is impossible to compensate them perfectly which transient response is especially deteriorated such as large overshoot and slow tracking, when variation of grid impedance or measurement error occurs. However, complex vector current control can improve stability and response characteristic of current control regardless of the situation as before. Decoupling controller and complex vector controller are represented through complex forms, and these controllers are analyzed by using frequency response in s-domain, respectively. It is verified that complex vector controller has more superior response characteristic than decoupling controller through MATALB, PSIM and experimental in 5kW grid-connected inverter when L filter parameter is varied from 1.1mH to increase double, 2.2mH.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.416-418
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• 1997

Stable power source and fast control response are important for the generator excitation system. To stabilize the control of excitation circuit the PI controller for excitation current has been used. But the response of the system with this conventional control technique is very poor, especially in transient response with a predictive current control, the response of the excitation system can be improved. In this study, it is verified by the PSIM simulation.

• Nuclear Engineering and Technology
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• v.49 no.1
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• pp.141-147
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• 2017

Mechanical shim is an advanced technology for reactor power and axial offset control with control rod assemblies. To address the adverse accuracy impact on the ex-core power range neutron flux measurements-based axial offset control resulting from the variable positions of control rod assemblies, the lead-lag-compensated in-core self-powered vanadium detector signals are utilized. The prompt ${\gamma}$ current of self-powered detector is ignored normally due to its weakness compared with the delayed ${\beta}$ current, although it promptly reflects the flux change of the core. Based on the features of the prompt ${\gamma}$ current, a method for configuration of the lead-lag dynamic compensator is proposed. The simulations indicate that the method can improve dynamic response significantly with negligible adverse effects on the steady response. The robustness of the design implies that the method is of great value for engineering applications.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.495-498
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• 2000

In this paper, generation form of displacement current was compared and measured with air-water interfacing induce monolayers which 8A5H with azobenzene and arac.acid mixed. Light response of two monolayers which chain length are different was compared and measured though they are the same isomer. The experimental results are as following; In the displacement current form of mixed monolayers and 8A5H, mixed monolayers which chain length is longer than that of 8A5H caused the displacement current about 40[fA] mole. This is the reason chain length of hydrophobicity in mixed monolayers is longer than that of 8A5H In the case of light stimulus mixed monolayers reacted less than 8A5H about 9[fA]. This is the reason molecule dynamic behaviour in cia and trans was net activated due to its very long chain length.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.11a
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• pp.199-201
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• 2007

This paper presents the installation of measuring system for the transient behaviors of grounding system impedances using portable impulse current generator. The measuring system is controller, with controller, power supply, impulse current generator and data aquisition system. In the evaluation of the impulse response in a ground electrode, the step response is calculated based on the ratio of the voltage and current observed.