Mobile QR Code QR CODE : Journal of the Korean Institute of Illuminating and Electrical Installation Engineers

Journal of the Korean Institute of Illuminating and Electrical Installation Engineers

ISO Journal TitleJ Korean Inst. IIIum. Electr. Install. Eng.

LED도로조명 수명연장을 위한 모듈진단과 전류평형기술 Module Diagnosis and Current Balancing Technology to Extend LED Lighting Life

Yong-Ha Kim

This study is to develop and experiment with a controller for LED module diagnosis and current balancing. For this, to the respective modules used in the lighting devices were applied with current balancing to keep the heat of all LED elements, By having the existing constant current converted replaced with a constant voltage converter, and by using a current balancing circuit, the respective modules’ current control can be enabled. The currents of the respective modules are to be determined by the PWM Duty of the MCU. The fact that the current control for the respective modules through the current balancing circuit is possible has the following advantages: first, an improvement in the current imbalance due to the tolerance of the LED element. Second, the resolution to the excessive set power for the LED module and concentrated current in existing systems when open/short states occur to the LED module.

태양광 발전을 이용한 LED-배터리 시스템을 위한 Flyback DC/DC 컨버터 모델링 및 제어기 설계 A Flyback DC/DC Converter Modeling and Controller Design for the LED-Battery System using PV(Photovoltaic) Energy

Jin-Yong Bae

This paper considers the Flyback DC/DC converter modeling and controller design for the LED-battery system using PV(Photovoltaic) energy. Recently, they have many concerns about battery charger and DC distribution system for green energy. This paper discusses the modeling of the Flyback DC/DC converter for LED lighting and battery charger with small-signal modeling. Also, the voltage mode control method and the current mode control method are compared for the Flyback DC/DC converter. Frequency-responses predicted by the small-signal modeling is verified by MATLAB simulation. The feature and design considerations are illustrated and verified through the experiment with a 40㎑ MOSFET based experimental circuit.

3상 비선형 부하에서 수동형 필터의 설치전후 역률 변동에 관한 연구 A Study on the Power Factor Variation Before and After Installation of Passive Filter in Three-Phase Nonlinear Load

Young-Jeen Park ; Jong-Gyeum Kim

Among the loads used by the customers, there are linear loads such as electric lamps and heat, and nonlinear loads such as converters and inverters. In a typical linear load, an inductive load has a low power factor, so a capacitive load such as a capacitor is used to improve the power factor. For nonlinear load such as power converters, harmonics components are a problem and need to be reduced. When the passive filter is used to reduce harmonics of a particular order current, the capacitor has a component that makes the phase of the current precede the phase of the voltage, so that the power factor can be preceded. If the power factor closes to unity, but it becomes a problem if it becomes a negative area. In this study, we analyze how the power factor is changed by parameter change of passive filter installed to reduce the harmonic current of a particular order when three-phase nonlinear is used.

이종전원을 이용한 모바일용 다중레벨 충전 토폴로지 Multi Level Charging Topology for Mobile using Dual Voltage Source

Soo-Yeon Kim ; Dong-Young Woo ; Seong-Mi Park ; Sung-Jun Park

Recently, the use of various mobile device such as electric bicycles is rapidly increasing due to the environmental pollution caused by the use of fossil fuels. As a power source for mobile which are free to move, the use of the battery is becoming common and a battery system having various voltages and capacities matching the characteristics of the equipment is used. However, most mobile devices require a dedicated charger, have disadvantaged that the charger must be accompanied at all times for charging. Therefore, this paper proposes a charging topology that can deal with various voltages and capacities of battery for mobile. The proposed charging topology is a multi-level charging topology using a dual voltage source and in order to reduce the current ripple rate according to the charging voltage, we applied the switching variable method according to the charging voltage level setting. We also verify the validity of the proposed topology through simulation using Psim and prototype for experiments.

고복굴절 광섬유에 제작된 광섬유 투과형 격자를 이용한 굽힘과 온도의 분리 측정에 관한 연구 A Study on Separate Measurement of Curvature and Temperature using Fiber Transmission Grating Fabricated on High Birefringence Fiber

Jinsil Han ; Yong Wook Lee

In this study, we propose an optical fiber sensor capable of separately measuring curvature and temperature by utilizing a fiber transmission grating(FTG) written on high birefringence fiber(HBF) with a CO2 laser. By fabricating an FTG on HBF(HB-FTG), two resonance dips A and B with different wavelengths of 1480.0 and 1568.8nm could be obtained, respectively, for two orthogonal input polarization states. The bending sensitivities of the two resonance dips A and B of the HB-FTG were measured to be 23.70 and 34.44nm/m-1 in a curvature range from 1.41 to 2.30m-1, and their adjusted R2 values representing the linearity of the sensor response were evaluated as 0.992 and 0.981, respectively. When the ambient temperature of the HB-FTG changed from 35 to 85°C by a step of 10°C, the temperature sensitivities of the dips A and B were measured to be 0.141 and 0.038nm/°C, and the R2 values were evaluated as 0.988 and 0.997, respectively. Using these pre-calculated four sensitivity coefficients and linearity of bending and temperature sensitivities measured in two resonance dips, the possibility of separate measurement of bending and temperature applied to the HB-FTG was presented.

제주 전기자동차 충전인프라 실증단지 충전패턴을 고려한 공동주택 전력수요예측에 관한 연구 A Study on Power Demand Prediction of the Apartment Housing Considering Charging Usage Pattern of EV Charging Infrastructure Demonstration Complex in Jeju

Og-Man Choi ; Jin-Su Kim ; An-Ki Lee ; Han-Jin Kim ; Jae-Chul Kim

This paper aims to study on prediction of power demand considering the charging usage pattern of the demonstration apartment in Jeju. The various researches are conducted over power usage rate, many studies show that the capacity of power transformer are over-designed considering the current power usage is low. The study is analyzed that the average charging power for once is 20.5㎾h and the average SoC(State of Charge) is 50.7% considering driver charging pattern, and the simultaneous charging rate reaches 43.7% at around 8 pm. It is necessary to secure the current design capacity of transformer until the countermeasure for the electrical method are established based on the result of the reliable study over EV charging power, since the transformer could be overloaded considering the practical usage rate of the existing apartments transformer and the charging demand by electric vehicles in 2030.

Implementation of the Zero Current Transition PWM Boost Converter using Digital Signal Processor Implementation of the Zero Current Transition PWM Boost Converter using Digital Signal Processor

Woo-Cheol Jeong ; Hong-Je Ryoo

There are various solutions for reducing turn-off loss of insulated gate bipolar transistor (IGBT). The ‘zero current transition pulse width modulation’ (ZCT-PWM) technique is one of them. For ZCT-PWM technique, the gate signal of auxiliary switch, which is synchronized to the gate signal of main switch is needed. This paper describes the implementation of both gate signals which is comprised of the main switch and the auxiliary switch using a digital signal processor (DSP), and 300-W ZCT-PWM boost converter is designed and implemented to verify ZCT technique.