Mobile QR Code QR CODE : The Transactions of the Korean Institute of Electrical Engineers

오차보정알고리즘을 고려한 방사기저함수 신경망의 일별 최대전력수요예측 적용에 관한 연구 Error Correction Algorithm based Radial Basis Function Network for Daily Peak Electric Load Forecasting

http://doi.org/10.5370/KIEE.2019.68.2.221

정희명(Hee-Myung Jeong) ; 김규한(Kyu-Han Kim) ; 박준호(June Ho Park)

In this study the error correction algorithm base Radial Basis Function network was proposed as a novel approach to forecast daily peak electric load more accurately. 2014-2016 KOREA dataset was employed to evaluate and validate the proposed approach. Obtained results were compared with feedforward network. This study showed that the proposed approach can be applied to forecast daily peak electric load effectively.

탐라해상풍력발전단지의 확률적 시뮬레이션 방법을 이용한 Capacity Credit의 평가 Capacity Credit Evaluation of Tamla Offshore Wind Farm by Using of Probability Simulation Method

http://doi.org/10.5370/KIEE.2019.68.2.228

정세민(Semin Jeong) ; 오웅진(Ungjin Oh) ; 이연찬(Yeonchan Lee) ; 최재석(Jaeseok Choi) ; 임진택(Jintaek Lim) ; 이기백(Kibaek Lee)

This study is described an algorithm for probabilistic production cost credit evaluation of wind turbine generators (WTG) with multi-state and aims to analysis the reliability of wind power generator in Jeju Island power system in order to maintain the operational state of power system at the reliability level. An analysis on generated capacity of wind power generator with Tamla offshore wind farm, which owned by KOEN(Korea South-East Power Co.Ltd.) and without Tamla offshore wind farm has been done in terms of Effective Load Carrying Capability(ELCC) and Capacity Credit(C.C.) in power system from the perspective of Loss of Load Expectation(LOLE). Case studies in this paper demonstrates how it changes the ELCC and C.C. according to the changing of wind speed in the Tamla offshore wind farm.

풍력발전단지에서 코로나 영향과 피뢰기 접지방식에 따른 낙뢰 과전압 분석 Analysis of Lightning Overvoltage According to Grounding Method and Corona Effect of Lightning Arrester in Wind farm

http://doi.org/10.5370/KIEE.2019.68.2.235

김진혁(Jin-Hyuk Kim) ; 김규호(Kyu-Ho Kim) ; 우정욱(Jung-Wook Woo)

It is important to reduce the impact of lightning strikes because lightning can create overvoltage in the grid of the wind turbine and affect power quality. One of the ways to improve the stability of power facilities used in power systems is to use power surge arresters and to protect against transient overvoltage and surges in normal operation. So This paper analyzes the influence of overvoltage caused by lightning when the ground impedance is changed considering the grounding method of the lightning arrester and the corona effect in the wind farm.

NRC DC를 위한 APR1400 전력 계통 설계 Electrical Power System Design of APR1400 for NRC DC

http://doi.org/10.5370/KIEE.2019.68.2.241

하체웅(Che-Wung Ha)

APR1400 NRC(Nuclear Regulatory Commission) DC(Design Certification) project was undertaken as a part of the UAE Nuclear Business. Nonetheless, The project is a key factor to construct and operate nuclear plant in the USA. If APR1400 acquires DC from the NRC, KHNP will be possible to take firm foothold in the USA, and to increase significantly in the technical competitiveness in overseas export of korea-type nuclear power plant. APR1400's electrical power system is designed as follows. Not only Offsite but also onsite power systems are supplied to provide electrical power to unit auxiliaries that are necessary during normal operation and the RPS(Reactor Protection System) and ESF(Engineered Safety Feature)s that are necessary in abnormal and accident conditions. The offsite power system comprises of transmission lines, transmission line towers, switchyard components and a control system, transmission tie lines, main generator, generator circuit breaker(GCB), main transformer, unit auxiliary transformers(UATs), and standby auxiliary transformers(SATs). Under normal operating conditions, the main generator supplies power to the main transformer and UATs through an isolated phase bus and the GCB. The UATs are linked to the isolated phase bus between the GCB and main transformer. The onsite power system for the unit auxiliaries consists of four emergency diesel generators(EDGs), an alternate alternating current(AAC) gas turbine generator(GTG), and two onsite power distribution systems. The onsite power distribution system is linked to the site-specific switchyard via two separate and independent transmission tie circuits. One circuit is linked to the switchyard through the main transformer and UATs, and the other circuit is linked to the switchyard via the SATs. During normal operation, onsite power is supplied from the main generator through the UATs. During startup and shutdown, the GCB is open, and the onsite power is supplied from the transmission system through the main transformer and UATs.

히트펌프 및 연료전지 설치를 고려한 마이크로그리드 보급 정책 설계에 관한 연구 A Study on the Diffusion Policy Design for Microgrid Considering the Introduction of Heat Pump and Fuel Cell

http://doi.org/10.5370/KIEE.2019.68.2.247

황성욱(Sung-Wook Hwang) ; 김정훈(Jung-Hoon Kim)

In Korea, various microgrid pilot sites have been constructed and planned to verify the effectiveness for utilities, customers, industries and governments, respectively. But heat load and resources have been not considered in these microgrid sites. This is from the industrial environment of Korea, which the combination of electric power business and heat energy business. However, actual microgrid should include heat elements to achieve self energy sufficiency. For example, United States and Japan have various power and heat combined companies and their microgrids consists of electricity and heat resources. In this paper, a design method is proposed to develop the diffusion policy for microgrid including heat pump and fuel cell as demand side resource and supply side resource, respectively. To carry out case studies using HOMER, electricity and heat load daily curves and patterns are created considering the situation of Gasa Island. Policy makers will be able to utilize this design method to compare various configurations for microgrid including heat and electricity resources.

비접지계통에서 GVT 내부고장에 대한 보호기기 운용 알고리즘에 관한 연구 A Study on Operation Algorithm of Protection Device for Single Line Short Circuit of GVT in Ungrounded System

http://doi.org/10.5370/KIEE.2019.68.2.253

윤형익(Hyoung-Ik Yoon) ; 최성식(Sung-Sik Choi) ; 이후동(Hu-Dong Lee) ; 남양현(Yang-Hyun Nam) ; 노대석(Dae-Seok Rho)

Generally, when a single ground fault in ungrounded system occurs, zero sequence voltage at 3rd winding of GVT(Ground Voltage Transformer) may be produced and then the system in which a ground fault occurred can be selectively blocked by the capacity of active current that drive the SGR(Selective Ground Relay) according to CLR(Current Limited Resistor) in GVT. On the other hand, the secondary distribution system of the industrial site with the large-scale facility using several high-voltage motors is composed of main and local transformers and GVT is installed at each transformer. However, if the internal fault including short circuit of 3rd winding of the GVT installed at local transformer occurs due to the aging of the protective devices, the circuit breaker in the local transformer does not operate and the circuit breaker in the main transformer operates, and then main and local distribution system can be blackout. To overcome these problems, this paper analyzes the characteristics of short circuit at 3rd winding of GVT and proposes an operation algorithm of protection device to prevent the whole system blackout. And also this paper implements a simulator for protection device on ungrounded system and presents a modeling of the simulator using PSCAD/EMTDC. As a result of simulation based on various scenarios, it is confirmed that the proposed algorithm is useful and practical to prevent the whole system blackout.

역 프라이자흐 모델에 의한 투자율과 부하각을 이용한 히스테리시스 전동기의 동적 특성 해석 연구 A Study of Dynamic Characteristic Analysis for Hysteresis Motor Using Permeability and Load Angle by Inverse Preisach Model

http://doi.org/10.5370/KIEE.2019.68.2.262

김형섭(Hyeong-Seop Kim) ; 한지훈(Ji-Hoon Han) ; 최동진(Dong-Jin Choi) ; 홍선기(Sun-Ki Hong)

Previous dynamic models of hysteresis motor use an extended induction machine equivalent circuit or somewhat different equivalent circuit with conventional one, which makes unsatisfiable results. In this paper, the hysteresis dynamic characteristics of the motor rotor are analyzed using the inverse Preisach model and the hysteresis motor equivalent circuit considering eddy current effect. The hysteresis loop for the rotor ring is analyzed under full-load voltage source static state. The calculated hysteresis loop is then approximated to an ellipse for simplicity of dynamic computation. The permeability and delay angle of the elliptic loop apply to the dynamic analysis model. As a result, it is possible to dynamically analyze the hysteresis motor according to the applied voltage and the rotor material. With this method, the motor speed, generated torque, load angle, rotor current as well as synchronous entry time, hunting effect can be calculated.

승강기 도어용 자속교번 영구자석 전동기의 토크 맥동 저감 Torque Ripple Reduction in a Flux-Switching Permanent Magnet Motor for Elevator Door Applications

http://doi.org/10.5370/KIEE.2019.68.2.269

황홍식(Hongsik Hwang) ; 조정현(Jeonghyun Cho) ; 이치우(Cheewoo Lee)

A flux-switching permanent magnet (FSPM) motor using ferrite magnet is proposed to replace a permanent magnet synchronous motor (PMSM) for elevator door applications. The prototype of an FSPM motor has been built up for experimental validation. Back-electromotive force (EMF) is estimated to prove that simulated results are correct and reliable. The efficiency of an FSPM motor has been verified to be comparable to that of a PMSM in spite of using ferrite magnet, but there is a disadvantage in torque ripple due to the interaction of harmonic components between back-EMF and magneto-motive force (MMF). However, most of researches on an FSPM motor have been focused on eliminating the harmonic components of back-EMF. In this paper, the design process of an FSPM motor based on winding function theory has been given to diminish torque ripple by considering the harmonic components of back-EMF and MMF along with cogging torque at the same time.

자동차 연료 펌프용 BLDC 모터의 전자기적인 소음 저감에 관한 연구 A Study on the Electromagnetic Noise Reduction of BLDC Motor for Fuel Pump of Vehicles

http://doi.org/10.5370/KIEE.2019.68.2.277

김동기(Dong-Ki Kim) ; 이승우(Seung-Woo Lee) ; 윤덕용(Duck-Yong Yoon)

This paper proposes a driving method in order to reduce the electromagnetic noise of blushless DC motor for fuel pump of vehicles. In recent years, these motors have been widely employed in the electric fuel pumps because of its high-efficiency, high-reliability, compact size, light weight, and simple control method. However, despite the various advantages, brushless DC motors have realistic problems. These problems are acoustic noise and vibration, which are caused by torque ripple and sudden current fluctuation in the stator windings due to the mechanical structures and control methods. If the mechanical structures are redesigned or the control methods are improved, both cogging torque and torque ripple due to commutation can be reduced. Nevertheless, if quasi-square-wave currents are supplied to these motors by conventional methods, the stator windings may generate the electromagnetic noise and vibration within the audio frequency bands. In this paper, a sinusoidal-wave driving method is proposed to suppress the fluctuating currents. The reduction effects on noise and vibration are verified through computer simulations and experiments.

영구자석형 동기전동기 구동용 인버터를 150도 통전 방식으로 운전하기 위한 PWM 기법에 관한 연구 A Study on PWM Techniques for Driving PMSM Inverter by 150-Degree Conduction Method

http://doi.org/10.5370/KIEE.2019.68.2.285

이승용(Seung-Yong Lee) ; 윤덕용(Duck-Yong Yoon)

In this paper, we have studied the PWM techniques for operating inverter for PMSM with 150-degree conduction method. In the conventional upper switch PWM technique, only three upper switches perform PWM switching, so they are very much used and have a large switching loss compared to three lower switches. And torque ripple occurs due to circulating current flowing by difference of back-EMF generated between two stator windings of motor in PWM switching section of inverter where one upper switch for PWM switching is turned off and two lower switches are turned on when motor operate in high speed and at light load. So, we propose a six-switch asymmetrical discontinuous PWM(SADPWM) techniques in order to improve the disadvantages of upper switch PWM technique. The proposed PWM technique can be used as SADPWM1 and SADPWM2 technique by changing the order of PWM switching sections. Computer simulations and experiments were carried out for SPMSM of 750[W] class. Using proposed PWM technique, upper and lower switches have the same PWM switching operation. And circulating current did not flow in stator winding of motor under operating condition in which motor operate at high speed 3000[rpm] and at light load. In addition, it is confirmed that loss of switching elements in inverter is reduced at light load and torque ripple of motor does not occur. Also, in SADPWM2 technique freewheeling current does not flow in the non-conduction section and less operation loss results in comparison to SADPWM1 technique. Because proposed PWM technique can be realized only by software modification in conventional upper switch PWM technique, it can be widely used in applications using 120-degree conduction method. Also, it can be applied to inverter for BLDCM.

GaN FET를 이용한 동기식 DC-DC 컨버터 구동 기법에 관한 연구 A Study on Synchronous DC-DC Converter Driving Method using GaN FET

http://doi.org/10.5370/KIEE.2019.68.2.296

김태규(Tae-Kue Kim) ; 안호균(Ho-Gyun Ahn)

Recently, there have been many studies on power conversion systems using GaN devices. In particular, in the system of below 600V, GaN has a beneficial advantages over the SiC device. However, due to the characteristics of the GaN device, the parasitic capacitance and the threshold voltage are low, it is difficult to obtain an increase in efficiency even when a GaN device is substituted for a system using Si semiconductor due to ringing and faulty turn on. Especially, high frequency noise is often included in the PWM output stage of the IC due to the characteristics of the internal circuit. This noise affects the switching output and reduces the efficiency in the system which the GaN device is applied. In this paper, as one of the methods to solve this problem, we propose a method of analyzing PWM high frequency noise and removing it. In addition, we have been studied a method for improving the time delay caused by the added circuit, by using dead time and delay time compensation. The results of this paper are expected to be used as a method to improve efficiency when driving GaN devices.

가변 임피던스 매칭 네트워크를 이용한 영상 감시 Disposable IoT용 광대역 CMOS RF 에너지 하베스터 A CMOS Wideband RF Energy Harvester Employing Tunable Impedance Matching Network for Video Surveillance Disposable IoT Applications

http://doi.org/10.5370/KIEE.2019.68.2.304

이동구(Dong-gu Lee) ; 이두희(Duehee Lee) ; 권구덕(Kuduck Kwon)

This paper presents a CMOS RF-to-DC converter for video surveillance disposable IoT applications. It widely harvests RF energy of 3G/4G cellular low-band frequency range by employing a tunable impedance matching network. The proposed converter consists of the differential-drive cross-coupled rectifier and the matching network with a 4-bit capacitor array. The proposed converter is designed using 130-nm standard CMOS process. The designed energy harvester can rectify the RF signals from 700 MHz to 900 MHz. It has a peak RF-to-DC conversion efficiency of 72.25%, 64.97%, and 66.28% at 700 MHz, 800 MHz, and 900 MHz with a load resistance of 10kΩ, respectively.

저전계 이동도 모델을 이용한 P형 다이아몬드 쇼트키 장벽 다이오드의 순방향 전류-전압 특성 Forward Current-Voltage Characteristics for P-type Diamond Schottky Barrier Diodes Using Low-Field Mobility Model

http://doi.org/10.5370/KIEE.2019.68.2.310

김규남(Gyunam Kim) ; 문정현(Jeong Hyun Moon) ; 하민우(Min-Woo Ha)

In this manuscript, we reported forward current-voltage characteristics of p-type diamond Schottky barrier diodes using a low-field mobility model. A conventional hole mobility was fixed at 2000cm2/Vs while our low-field mobility model considered ionized impurity scattering and temperature dependency. When a doping concentration of a p- drift layer was 1014, 1015, 1016, and 1017cm-3, the hole mobility was 1803, 786, 279, and 115cm2/Vs at 3V, respectively. The calculated on-resistance of the device was 3.28, 14.21, and 24.78 Ωmm at 200, 300, and 400K, respectively.

순수한 물 용매에서 Langmuir-Blodgett 법으로 제조한 이황화몰리브덴 박막의 전기적 특성 관찰 Observation of Electrical Characteristics of MoS2 Thin Films Synthesized by Langmuir-Blodgett Method in Pure Water Solvent

http://doi.org/10.5370/KIEE.2019.68.2.313

조대현(Dae-Hyun Cho) ; 이승기(Seoung-Ki Lee) ; 이창구(Changgu Lee)

In this study, nanometer-thick molybdenum disulfide (MoS2) films were fabricated by Langmuir-Blodgett method and morphological characteristics and electrical properties were observed. The thickness of the thin films measured by AFM was about 10 nm, and the sheets constituting the thin films had a width of 100-400 nm in the plane direction. This means that micrometer-level molybdenum disulfide powder is dispersed in pure water through ultrasonic waves and self-assembled in the form of a thin film from nano-sheets by the Langmuir-Blodgett method. Raman spectra of the thin films showed that the nanometer-thick molybdenum disulfide films were obtained without the chemical change of the molybdenum disulfide. We conclude that the MoS2 films fabricated by Langmuir-Blodgett method have semiconducting property from the measurement of 2.5 times amplified current than dark state (at 0.5 V). Furthermore, we analyze the electrical properties of MoS2 film by measuring channel current depend on gate voltage. From the conventional I-V characteristic, we confirm that the MoS2 film has n-type semiconducting characteristic.

인버터서지용, 유/무기 나노 하이브리드 코일의 온도스트레스에 따른 절연파괴 수명 Insulation Breakdown Life due to Temperature Stress of Organic /Inorganic Nano Hybrid Coil for Inverter Surge

http://doi.org/10.5370/KIEE.2019.68.2.318

박재준(Jae-Jun Park)

The one nano hybrid rectangular coil was fabricated by dispersing SiO2 in PAI resin using a sol / gel method, and the another nano hybrid rectangular coil was fabricated by adding a flexible agent. To evaluate the dielectric breakdown lifetime, the dielectric breakdown lifetime was measured according to the change of temperature environment (30, 70, 100, 130, 150, 200 ℃) under an inverter surge (1.5kV/20kHz). Compared to the PAI original coil, the dielectric breakdown lifetime of the nano hybrid rectangular coil at 30 ℃ was improved by 23.23 times. The dielectric breakdown lifetime of the nano hybrid rectangular coil without the flexible agent was longer than that with the flexible agent at 100℃ or less. However, at 100 ℃ or higher, the life time of the dielectric breakdown of the rectangular coil added with the flexible agent was further improved.

LSR Nano Silica Composites에 대한 HVDC의 IPT 특성연구 Study on Inclined Plate Tracking and Erosion Characteristics of HVDC for Liquid Silicone Rubber Nano Silica Composites

http://doi.org/10.5370/KIEE.2019.68.2.326

박재준(Jae-Jun Park)

In this paper, two types of SiR-Nano Composites were fabricated to develop HVAC insulator. Tracking and erosion characteristics of ± HVDC voltage 3.5 kV were investigated using IPT system based on AC IEC regulations. In tracking and erosion, (-) HVDC than (+) HVDC resulted in a large number of arc leakage currents due to the drying-arc discharge. However, the results of tracking and erosion show that (+) HVDC is more severe than (-) HVDC. (+) HVDC generated many intermittent surface discharges. Unlike this, (-) HVDC caused continuous discharge from the moment when the dross was dropped on the lower electrode. (+) HVDC occupies a large number of moving discharges from the lower electrode to the upper electrode, and (-) HVDC concentrates on the lower electrode and discharges and erodes.

RFID 태그 안테나들의 초근접 시의 격리도 및 전기적 특성을 향상시키는 설계 How to Improve Isolation and Electrical Characteristics of Two RFID Tag Antennas, When They Are Located By An Extremely Small Gap

http://doi.org/10.5370/KIEE.2019.68.2.334

박희준(Heejun Park) ; 압둘 레만(Abdul Rehman) ; 이창형(Changhyeong Lee) ; 진성훈(Sung Hun Jin) ; 강승택(Sungtek Kahng)

In this paper, we show a new scheme to tackle the problems of high electromagnetic-coupling, poor impedance- matching. and degraded radiation-characteristics of two RFID tag antennas, when they are located with an extremely short distance. As giving it a variety of tries such as periodic EBG-type structures and notch-making stubs, we can get an optimal device to lower the electromagnetic coupling and to match the input impedance of both of the tag antennas. Even for a UHF-band, the device is very thin less than 1 mm unlike other isolation-enhancers which are thick or multi-layered. The dips in the S11 and S21-curves are generated at the target frequency, which means excellent impedance match and lowered interference for the two tag dipole-antennas. This is helpful to higher thruput in RFID.

동적 시스템의 각가속도 추정을 위한 데이터 기반 상태관측기 설계와 필터링 기법 Data-Driven State Observer Design and Filtering Technique for The Angular Acceleration Estimation of Dynamic Systems

http://doi.org/10.5370/KIEE.2019.68.2.342

이상덕(Sang-Deok Lee) ; 정슬(Seul Jung)

In this paper, we propose a data-driven state observer design and a filtering technique for the estimation of the angular acceleration information of dynamic systems. Angular acceleration information is quite useful for the control of vehicles, mobile robots, and joint systems. When the accurate angular acceleration state is estimated, we can construct a joint independent control scheme neglecting the dynamically coupled effects between the joints or links. An angular acceleration state observer based on the data of the measurable encoder is designed. However, such a data-driven state observer may show the peaking effect when the data are not enough or when the sampling rates are not fast. A simple first-order complementary filter is proposed to deal with the peaking effect problem. The proposed method is verified by the simulation and experimental studies.

컴퓨터 보조 진단 시스템 기반 치아우식증 검출 기법 비교 분석 Comparative Analysis of Dental Caries Detection Technologies based on Computer-aided Diagnosis System

http://doi.org/10.5370/KIEE.2019.68.2.350

김대한(Dae-han Kim) ; 조현종(Hyun-chong Cho)

Dental caries, a gradual bacterial damage to teeth, is one of the most common diseases and is still a major cause of tooth loss. It can be divided into 7 scores based on the ICDAS(International Caries Detection and Assessment System) according to the tooth condition. Early detection and treatment of dental caries can reduce the costs as well as time. As computer performance has been improved, machine learning and image processing technologies are introduced to detect and diagnose dental caries. Computer-aided Diagnosis(CADx) can assist dentists in the interpretation of several oral digital images or X-ray image. Dental caries detection system using CADx has four steps. First is image enhancement to improve the original image. Second is tooth detection which extract the tooth area from the oral structures. Third is caries detection which finds the caries lesion in tooth area. The fourth is classification which analyzes and classifies carious lesions. In this paper, we survey and introduce the various dental caries detection methods based on CADx.

딥러닝 기반 드론 검출 및 분류 Deep Learning Based Drone Detection and Classification

http://doi.org/10.5370/KIEE.2019.68.2.359

이건영(Keon Young Yi) ; 경덕환(Deokhwan Kyeong) ; 서기성(Kisung Seo)

As commercial drones have been widely used, concerns for collision accidents with people and invading secured properties are emerging. The detection of drone is a challenging problem. The deep learning based object detection techniques for detecting drones have been applied, but limited to the specific cases such as detection of drones from bird and/or background. We have tried not only detection of drones, but classification of different drones with an end-to-end model. YOLOv2 is used as an object detection model. In order to supplement insufficient data by shooting drones, data augmentation from collected images is executed. Also transfer learning from ImageNet for YOLOv2 darknet framework is performed. The experimental results for drone detection with average IoU and recall are compared and analysed.

NOC 인터커넥트를 활용한 메모리 반도체 병렬 테스트 효율성 개선 Improving Parallel Testing Efficiency of Memory Chips using NOC Interconnect

http://doi.org/10.5370/KIEE.2019.68.2.364

홍찬의(Chaneui Hong) ; 안진호(Jin-Ho Ahn)

Generally, since memory chips should be tested all, considering its volume, the reduction in test time for detecting faults plays an important role in reducing the overall production cost. The parallel testing of chips in one ATE is a competitive solution to solve it. In this paper, NOC is proposed as test interface architecture between DUTs and ATE. Because NOC can be extended freely, there is no limit on the number of DUTs tested at the same time. Thus, more memory can be tested with the same bandwidth of ATE. Furthermore, the proposed NOC-based parallel test method can increase the efficiency of channel usage by packet type data transmission.

양면수광형(Bifacial) 태양광 모듈을 위한 고투과도 PV(Photovoltaic) 백쉬트의 연구 Study on High Transparent PV Backsheet for Bifacial Solar Module

http://doi.org/10.5370/KIEE.2019.68.2.370

박지수(Jisoo Park) ; 노은섭(Eun-Seob Noh) ; 윤종국(Jong-Kuk Yoon) ; 박종세(Jong-Se Park) ; 장현태(Hyun-Tae Jang) ; 최재호(Jaeho Choi) ; 구경완(Kyung-Wan Koo)

PV module protective film plays an important role in protecting the solar cell from external environment by anti-hydrolysis polyester, UV resistance and mechanical properties. The backsheet was manufactured by using Roll-to-Roll dry laminating process. Recently, various research and evaluations have been conducted in order to increase the generation power output of solar panel. In this study, we have experimented the basic properties of the coating type outer layer and inner layer materials for high tranparency for UV and visible light spectrum ranges in order for the bifacial solar panel. Long-term environment weatherability tests were conducted for confirming 25 year reliability in the field such as PCT, UV, and power efficiency degradations in case of application of bifacial solar module. As the evaluation result, high transparent coating type protection film can be available to bifacial solar panel by using UV-cut PVDF coating layer and high reliability primer layer.

회전자 위치 검출회로와 저가용 구동회로를 이용한 3상 BLDC 전동기 구동제어 시스템 Three Phase BLDC Motor Driving Control System with Rotor Position Detection and Low Cost Driving Circuit

http://doi.org/10.5370/KIEE.2019.68.2.376

윤용호(Yong-Ho Yoon)

In order to increase reliability and reduce system cost, this paper studies particularly applicable method for sensorless BLDC motor drive system with 4-switch inverter. Over the years, traditionally, 6-switch 3-phase inverters have been widely utilized for variable speed alternating current motor drives. Recently, some efforts have been made on the application of 4-switch 3-phase inverter for uninterruptible power supply and variable speed drives. This is due to some advantages of the 4-switch 3-phase inverter over the conventional 6-switch 3-phase inverters such as reduced price due to reduction in number of switches, reduced switching losses, number of interface circuits to supply logic signals for the switches, simpler control algorithms to generate logic signals, less chances of destroying the switches due to lesser interaction among switches, and less real-time computational burden. Also rotor position information is extracted by indirectly sensing the back EMF from only one of the 3 terminal voltages for a 3-phase BLDC motor. Depending on the terminal voltage sensing rotor position, active filter is used for position information. This leads to a significant reduction in the component device of the sensorless circuit.