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.

직교 입력 편광에 따른 위상 천이 장주기 격자의 pH 및 온도 응답에 관한 연구 Study on pH and Temperature Responses of Phase-Shifted Long-Period Fiber Grating Depending on Orthogonal Input Polarization State

Seul-Lee Lee ; Yong Wook Lee

In this paper, we demonstrated an optical fiber sensor based on a phase-shifted long-period fiber grating (PS-LPFG) that could realize simultaneous measurement of surrounding pH and temperature variations. The PS-LPFG composed of a grating-free fiber region (GFFR) in the middle of two identical LPFGs was fabricated on high-birefringence fiber (HBF) with CO2 laser pulses. In addition, a π phase shift formed by setting the length of the GFFR as half of the grating period of an LPFG allows a transmission dip to split into two attenuation bands at two different resonance wavelengths. Since HBF can preserve a linear state of polarization (SOP) if the input SOP is aligned with one of its two principal axes (fast or slow axis), a PS-LPFG inscribed on HBF (HB-PS-LPFG) can create two different transmission spectra for two orthogonal input SOPs, i.e., linear horizontal polarization (LHP) and linear vertical polarization (LVP). To investigate pH and temperature responses of the fabricated HB-PS-LPFG, the dip wavelength separation between two different attenuation bands was used as a sensor indicator for an LHP or LVP input SOP. Consequently, pH- and temperature-induced wavelength variations of the two sensor indicators showed linear and independent spectral responses to both pH and temperature variations in a pH range from 3 to 11 and a temperature range from 25 to 65 °C. With these unique pH or temperature responses of the two sensor indicators, the fabricated sensor could realize simultaneous measurement of pH and temperature.

고반복 펄스 전원용 게이트 드라이버 회로 설계 Gate Driver Circuit Design for High Repetition Pulsed Power Modulator

Hyun-Bin Jo ; Seung-Ho Song ; Seung-Hee Lee ; Hong-Je Ryoo

In this paper, a new gate driver circuit is proposed to drive high voltage SiC MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) of a solid-state pulsed power modulator. This gate driver circuit is designed to output pulses with repetition rates of several hundred kpps, and 1200V SiC MOSFETs are used as the main switch. In addition, a compact discharge structure was considered so that the volume of the modulator generating an average output of 10 kW could be designed to be within 26 liters, and thus a compact discharge structure based on an integrated gate driver of a discharge switch and a pull-down switch was implemented. In the experiment, synchronous stability was confirmed through gate synchronous driving tests of 12 discharge switches and pull-down switches, respectively. Based on this, a high repetition pulse output of 10 kV 150 kpps was finally performed, and the reliable operation of the proposed new gate driver and discharge circuit was verified.

전기 자전거에 적합한 스포크 형 및 자속 교번 영구자석 전동기 설계와 특성 비교 Design and Characteristics Comparison of Spoke Type Interior Permanent Magnet Synchronous Motor and Flux Switching Permanent Magnet Motor for Electric Bicycles

Yongha Choo ; Changhwan Kim ; Cheewoo Lee

In this paper, a spoke-type interior permanent magnet synchronous motor(IPMSM) and a flux switching permanent magnet(FSPM) using ferrite magnet designed for electric bicycles and compare the advantages and disadvantages of the two motors. The motors were optimized in the same design order and the efficiency map was analyzed to verify the performance of each driving section. From the results, the FSPM motor is cheaper, but the performance is lower than the spoke-type IPMSM, and the performance is excellent only at high speed. Therefore, the spoke-type IPMSM, which has good average efficiency in all driving areas, is more suitable for electric bicycles.

가스냉방기기의 전력대체효과 산정에 의한 회피비용 산정 Calculation of Avoid Cost Considering The Electric Power Peak-Cut Effect of Gas Cooling Equipment

Yong-Ha Kim ; Bok-Mahn Jung ; Hye-Seon Lee ; Sang-Hwa Han ; Jea-Hoon Jung

The electric power peak - cut effect of gas cooling is defined as the electric power (peak cut) that can be replaced by the gas cooling load accompanying the maximum power generation. In order to measure this, it is necessary to accurately grasp gas consumption, equipment operation rate, and load rate when the maximum load occurs. Past research has difficulty in estimating the cooling gas consumption on peak days, the disadvantage of not reflecting the characteristics of individual gas cooling devices well, and the cooling gas consumption on peak days is estimated from the monthly cooling gas consumption. There was a disadvantage that it was difficult to do. This study solved the existing problems and calculated the avoid cost of reliable gas cooling equipment by considering the electric power peak capacity replacement contribution rate and the electric power amount replacement contribution rate.

배전지능화 단말장치의 모의시험을 위한 가상 배전계통 HILS 시스템 개발 Development of Virtual Distribution HILS System for Simulation Tests of Feeder Remote Terminal Unit for Distribution Automation System

Won-Seok Lee ; Jin-Uk Song ; Seon-Hwan Hwang

This paper proposes a virtual distribution HILS(Hardware-In-the-Loop Simulation) system for testing of FRTU(Feeder Remote Terminal Unit) for distribution automation systems. Recently, the distribution automation systems have been complicated because of the reliability improvement of the power system, new power distribution facilities, and upgrading the operating system. However, real-time digital simulators are difficult to build systems due to expensive facilities and cannot implement actual distribution automation systems. Therefore, in this paper, the HILS system is developed by using FRTU, interface devices based on DSP(Digital Signal Processor), Labview monitoring through the TCP/IP communication, and real-time power system analysis simulator. The proposed HILS system is verified through the results of systematic analysis of distribution automation systems, real-time simulation, and functional verification by using the feeder remote terminal unit.

유도발전기 직입 기동에 적합한 변압기의 용량 산정에 관한 연구 Research on Capacity Calculation of Transformers Suitable for Direct Starting of Induction Generator

Young-Jeen Park ; Jong-Gyeum Kim

Induction generators have the advantages of simple structure, low cost, and easy maintenance, like induction motors. So, Induction generators are often used in small hydro power plants where the output of the generator is not high. The induction generator has a drawback that it causes a voltage drop due to a high inrush current when the induction generator is directly inserted and is connected to the system like the start of the induction motor. When a voltage drop occurs in the same bus line, it may affect the devices connected in parallel and prevent them from operating, or cause a malfunction. In order to reduce the influence of the starting current of the induction motor or the inrush current of the induction generator, a number of studies have been proposed that have proposed various starting methods. The current reduction method for reducing the voltage drop is the addition of another starting system for the induction motor and induction generator. In this study, using the method applied for calculating the capacity of the emergency generator, the capacity of the transformer connected to the system after the direct starting of the induction generator was calculated considering the magnitude of the voltage drop. As a result of analysis, it was confirmed that the voltage drop on the primary side of the transformer was very low, but the secondary side of the transformer had a large difference in the voltage fluctuation rate depending on the transformer capacity.

Two-Step 구조의 인공신경망 기반 Hybrid AC/DC Microgrid 운영 기법 Hybrid AC/DC Microgrid Operation Method based on Artificial Neural Network of Two-Step Structure

Tae-Gyu Kim ; Hoon Lee ; Chang-Gyun An ; Yoon-Seong Lee ; Kyung-Min Kang ; Junsin Yi ; Chung-Yuen Won

This paper proposes an artificial neural network(ANN) based energy management system(EMS) for hybrid AC/DC microgrid with renewable energy source and distributed generation(DG). The operation of microgrid is divided into grid-connected mode and stand-alone mode according to whether or not the power converters are connected to the main AC grid. In grid-connected mode, the operation of energy storage system(ESS) is usually to maintain an appropriate value of state of charge(SOC). On the other hand, in stand-alone mode, the regenerative operation to the main AC grid is impossible, so additional control of ESS is required. However, in the case of small-scale distribution networks, data on power generation sources and load demands have non-linear characteristics, which makes it difficult to operate the EMS. Therefore, in this paper, ANN based EMS was applied to appropriately control the surplus and shortage of ESS power. The proposed ANN was constructed with a two-step structure to achieve high accuracy even with less repetitive learning. To implement the proposed method, a laboratory-scale interlinking converter based hybrid microgrid was constructed and its validity was verified through the experimental results.