• The Transactions of the Korean Institute of Electrical Engineers P
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• v.51 no.4
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• pp.169-174
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• 2002

The developments of the solar and the wind power energy are neccessary since the future alternative energies that have no pollution and no limitation are restricted. Currently power generation system of existing problems, combined generation system of photovoltaic(400W) and wind power generation system(400W) was suggested. It combines wind power and solar energy to have the supporting effect from each other. However, weather condition, power compensation device that uses elastic energy of spiral spring to combined generation system was also added for the present study. In an experiment, when output of system gets lower than 12V(charging voltage), power was continuously supplied to load through the inverter by charging energy obtained from generating rotary energy of spiral spring operates in small scale generator.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.173-176
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• 2000

In this paper, we investigated the surface degradation of HTV silicone rubber used for a polymeric insulator by UV irradiation. To study the surface ageing properties by W irradiation, we used the corona discharge charging and contact angle. Therefore, we observed the change of surface charge retention and decrease of surface hydrophobicity. Also, we discussed the chemical change in the surface range using the analytic equipment such as SEM, ATR-FTIR, ESCA. Therefore, it is found that the scissor of characteristic bonding and the reattachment of oxidant bonding was developed by UV rays radiation. As discussing the corona ischarge charging and the change of contact angle, it is found the effect of UV irradiation and the mechanism of chemical reaction

• Transactions on Electrical and Electronic Materials
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• v.4 no.6
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• pp.32-37
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• 2003

In this paper, the trap characteristics of thin silicon oxides is investigated in the ULSI implementation with nano structure transistors. The stress and transient currents associated with the on and off time of applied voltage were used to measure the distribution of high voltage stress induced traps in thin silicon oxide films. The stress and transient currents were due to the charging and discharging of traps generated by high stress voltage in the silicon oxides. The transient current was caused by the tunnel charging and discharging of the stress generated traps nearby two interfaces. The stress induced leakage current will affect data retention in electrically erasable programmable read only memories. The oxide current for the thickness dependence of stress current, transient current, and stress induced leakage currents has been measured in oxides with thicknesses between 113.4nm and 814nm, which have the gate area 10$\^$-3/ $\textrm{cm}^2$. The stress induced leakage currents will affect data retention, and the stress current and transient current is used to estimate to fundamental limitations on oxide thicknesses.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.232-233
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• 2012

This paper presents an effective control scheme for an electric vehicle battery charger where a symmetrical bridgeless power factor-corrected converter and a buck converter are cascaded. Both converters have been popular in industries because of their high efficiency, low cost, and compact size, hence combining these converters makes the overall battery charging system strongly efficient. Moreover, this charger topology can operate at universal input voltage and attain a desired battery current and voltage without ripple. In order to achieve a unity input power factor and zero input current harmonic distortion, the proposed control scheme adopts duty ratio feed-forward control technique in both current and voltage control loop. Additionally, in the current loop, its reference is created by a phase-locked loop (PLL) block, leading to a pure sinusoidal input current although the input voltage waveform is being distorted. The feasibility and practical value of the proposed approach are verified by simulation and experiment with an 110V/60Hz ac line input and 1.5kW-72V dc output of the battery charging system.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.1
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• pp.80-84
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• 2012

Recently, the small scale photovoltaic (PV) electronic devices are drawing attention as the upcoming PV generation system. The PV system is commonly used in small scale PV applications such as LED lighting and cell phone. This paper proposes photovoltaic output sensorless (POS) maximum power point tracking (MPPT) control for a small scale charging system of PV-nickel metal hydride battery using field-programmable gate array (FPGA) controller. A converter is connected to a small scale PV cell and battery, and performs the POS MPPT at the battery terminal current instead of being at the PV cell output voltage and current. The FPGA controller and converter operate based on POS MPPT method. The experimental results show that the nickel metal hydride battery is charged by the maximum PV output power.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.08a
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• pp.19-24
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• 2002

Static electricity is an everyday phenomenon. There can be few of us who have not experienced a static shock after sliding across a car seat. Other static nuisance effects include the cling of some fabrics to the body, the sticking of a plastic document cover, or the attraction of dust to a TV or computer screen. However, static electricity has been a serious industrial problem. The age of electronics brought with it new problems associated with static electricity and electrostatic discharge. And, as electronic devices became faster and smaller, their sensitivity to ESD increased. In this work, We are study on the control technique of electo-static discharges using semiconductor circuits. Our circuits are prevented well to electrostatic shock or damages from triboelectric charging in cars everyday life.

• International journal of advanced smart convergence
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• v.8 no.1
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• pp.98-105
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• 2019

Energy autonomy is a system that is sustained by energy from an independent and distributed source such as renewable energy. In this paper, we propose a robotic energy autonomy in which a robot obtains energy from a renewable energy source with a limited storage capacity. As an energy transfer method, wireless power transfer is used to solve the problem of the conventional contact charging method, mechanical complexity, and to obtain high energy transfer efficiency, the image information is used to align the transmitting and receiving coils accurately. A small scale thermoelectric energy source with boost converter, battery charger, and wireless power transfer coil is constructed and an actual charging experiment is conducted to verify the proposed autonomy system.

• Proceedings of the KIPE Conference
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• 2019.07a
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• pp.142-144
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• 2019

Nowadays, multi-MHz wireless power transfer (WPT) system has received a great concern of study due to its desirable characteristics such as user convenience, system compact and better safety as compared to the conventional DC-DC with cord. This paper presents a solution for WPT Lithium Batteries charger with Constant Current (CC) and Constant Voltage (CV) charging process. The proposed system consists of a high frequency class D power amplifier, a pair of PCB coil, transformable high-order resonant network and a full-bridge rectifier. The charger can be implemented CC /CV charging profile thanks to automatic reconfigurable resonant compensator. Therefore, the battery can be fully charged without the help of an additional DC/DC converter. The simulation and 50W-6.78-MHz hardware experimental results are presented to verify the feasibility of the proposed method and to evaluate the performance of the proposed wireless battery charger.

• Journal of Power Electronics
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• v.19 no.2
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• pp.394-402
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• 2019

This paper proposes a single-phase non-isolated onboard battery charger (OBC) for electric vehicles (EVs) that only uses small film capacitors at the DC-link of the AC-DC converter. In the proposed charger, an isolated DC-DC converter for low-voltage batteries is used as an active power decoupling (APD) circuit to absorb the ripple power when a high-voltage (HV) battery is charged. As a result, the DC-link capacitance in the AC-DC converter of the HV charging circuit can be significantly reduced without requiring any additional devices. In addition, some of the components of the proposed circuit are shared in common for the different operating modes among the AC-DC converter, LV charging circuit and active power filter. Therefore, the cost and volume of the onboard battery charger can be reduced. The effectiveness of the proposed topology has been verified by the simulation and experimental results.

• Progress in Superconductivity and Cryogenics
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• v.22 no.3
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• pp.1-6
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• 2020

This paper presents the analysis results on the electrical output performance characteristics of a 746 W high temperature superconducting generator (HTSG). The HTS field winding is charged by non-contact excitation method, i.e., contactless superconducting field exciter (CSFE) which is originated by rotary flux pump based on permanent magnet. In this paper, the preliminary current charging test was carried out using a 70 A CSFE to evaluate the performance of field exciter and analyze its non-contact excitation characteristics for the full-scale HTS field winding of the 746 W HTSG. First, the various contactless current-charging tests were conducted using assembly with HTS field winding and CSFE. Then, in order to estimate the output power performance characteristics of the 746 W HTSG, finite element analysis was conducted based on field excitation information which is experimentally measured under various operating conditions. Finally, the electrical output characteristics in no-load and load models were simulated by two-dimensional transient solver in ANSYS electromagnetics 19.0 release.