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

발전기 가속에너지를 이용한 고장파급방지장치 운전조건 완화용 전기저장장치 적정용량 산정방안 Required Capacity Assessment of Energy Storage System for Relieving Operation Condition of SPS Using Generator Acceleration Energy

http://doi.org/10.5370/KIEE.2019.68.1.1

송승헌(Seung-Heon Song) ; 최우영(Woo-Yeong Choi) ; 권한나(Han-Na Gwon) ; 국경수(Kyung Soo Kook)

Due to the highly concentrated power plants integrated through the limited transmission lines in Korea, a Special Protection System(SPS) has been applied to stabilize the power systems by instantly tripping the pre?determined generators in a large-scaled power plant when a fault occurs on the drawing transmission lines. Moreover, power outputs of those generators are constrained to avoid any activation of Under Frequency Load Shedding(UFLS) even after those generators are tripped by SPS action. For this, this paper proposes a method for calculating the required capacity of Energy Storage System(ESS) expected to relieve the operating constraints to generators using its fast response for controlling power system frequency. The proposed method uses the generator acceleration energy to derive the stable condition during the SPS action. In addition, its effectiveness is verified by the case studies adopting actual SPS operations in Korean power systems.

복합발전기 조합별 증분비 곡선 재설정에 관한 연구 A Study on the Resetting of Incremental Heat Rate Curve of Combined Cycle Unit by Combination

http://doi.org/10.5370/KIEE.2019.68.1.8

홍상범(Sang-Beom Hong) ; 최준호(Jun-Ho Choi)

Combined Cycle Unit(CC) generates the primary power from the Gas Turbine(GT) and supplies the remaining heat of the GT to the Steam Turbine(ST) to generate the secondary power from the ST. It plays a major role in terms of energy efficiency and Load Frequency Control(LFC). Incremental Heat Rate(IHR) curves of economic dispatch(ED) of CC is applied differently by GT/ST combination. But It is practically difficult because of performance test by all combinations. This paper suggests a reasonable method for estimating IHR curves for partial combinations (1:1~(N-1):1) using IHR curves when operating with GT alone(1:0) and with all(N:1) combinations of CC.

가공송전선 유도장해 특성을 고려한 최적 상배열 연구 Study on Optimal Phase Arrangement Considering the Characteristics of Inductive Interference from Overhead Transmission Lines

http://doi.org/10.5370/KIEE.2019.68.1.13

강경두(Kyung-Doo Kang) ; 김진규(Jin-Gyu Kim)

The domestic overhead transmission lines use a vertical configuration and reverse phase arrangement, but when there is a limitation in steel tower height because the transmission lines pass a height limit zone or special zone, an application of triangular arrangement is necessary, and a study on the optimal phase arrangement to minimize inductive interference for this is necessary. If conductor arrangement are changed, the action of electrostatic induction and electromagnetic induction becomes different from before changes, so the changed conductor arrangement should be reviewed in terms of inductive interference. So this paper presents an optimal phase arrangement to reduce inductive interference by calculating electrostatic induction and electromagnetic induction according to conductor arrangement.

시계열 모델을 이용한 행동기반 에너지 효율화 프로그램의 고객기준부하 산정 방안 Customer Baseline Load Calculation using Time Series Prediction Technique in Energy Efficiency Programs

http://doi.org/10.5370/KIEE.2019.68.1.19

고세현(Sae-Hyun Koh) ; 주성관(Sung-Kwan Joo) ; 이재희(Jae-Hee Lee) ; 문국현(Guk-Hyun Moon) ; 위영민(Young-Min Wi)

As global demand for energy, energy prices, and power generation has increased worldwide, the government is turning to supply-oriented electricity supply and demand policies, such as behavior-based energy efficiency programs. In order to measure the implementation effect of the behavior-based energy efficiency program, the energy reduction must be accurately calculated by calculating the customer baseline load.

제한급전하는 오프그리드의 독립형 마이크로그리드 최적 설계 및 경제성 평가를 위한 일부하곡선 추정 방안에 관한 연구 A Study on the Estimation Method of Daily Load Curve for the Optimization Design and Economic Evaluation of Stand-alone Microgrids Based on HOMER Simulation in Off-Grid Limiting the Supply of Electricity

http://doi.org/10.5370/KIEE.2019.68.1.27

남용현(Yong-Hyun Nam) ; 윤석민(Seok-Min Youn) ; 김정훈(Jung-Hoon Kim) ; 황성욱(Sung-Wook Hwang)

There is a growing interest in various microgrid solutions that supply electricity 24 hours a day to off-grid areas where are not connected with the main grid, and Korea has many positive effects by constructing overseas microgrids as a country operating the emission trading scheme. Since it is not clear how to obtain load curves that is one of the inputs of the HOMER used to design a microgrid optimization plan, or it is necessary to examine whether electricity is supplied to the peak load level of the areas where have not received the electricity benefits from the viewpoint of the demand management, a methodology should be developed to know the load composition ratio and the shape of the daily load curve. In this paper, the relative coefficient and average load information for each load group obtained from the survey are used besides peak load and total average load. A mathematical model is proposed to derive the load composition ratio in the form of a Quadratic Programming and the load forecasting is performed using simple linear regression with future indicators. The effectiveness of the proposed method is confirmed for the Philippine island region supported by Korea Energy Agency and the Asian Development Bank.

2차원 유한요소 해석을 이용한 고속용 마그네틱 기어의 형상에 따른 특성 해석 Characteristic Analysis of High Speed Coaxial Magnetic Gear by Two-Dimensional Finite Element Analysis

http://doi.org/10.5370/KIEE.2019.68.1.36

이정인(Jeong-In Lee) ; 신경훈(Kyung-Hun Shin) ; 방태경(Tae-Kyoung Bang) ; 이상화(Sang-Hwa Lee) ; 최장영(Jang-Young Choi)

In this paper, the characteristics of the coaxial magnetic gear according to the shape of the same gear ratio are analyzed using the two-dimensional finite element analysis. The rotor shape is SMCMG, CPCMG and RCMG. After this we analyzed the characteristics according to three shapes. Also, the amount of permanent magnet used in each shape was compared. Next, characteristics analysis of the magnetic gear according to the shape at the same torque was performed. And the total weight and efficiency of the magnetic gears were compared and verified.

TBM용 대용량 전동기의 기동 특성 및 개선 관한 연구 A Study on Starting Characteristic and Improvement for High Power Motor with Tunnel Boring Machine

http://doi.org/10.5370/KIEE.2019.68.1.44

김태규(Tae-Kue Kim) ; 안준영(Joon-Young An)

Tunnel Boring Machine's Technology has depends mostly on imports, currently domestic technology development was proceeding. There are many technologies in this field, above all, the large-capacity motor drive technology required for excavation is one of the core technologies. In particular, when several large motors are simultaneously starting, there are many problems due to a large starting current at that time, and it is difficult to design and operate a power receiving facility. In this paper, A method of reducing the starting current by using the regenerative power generated by the deceleration of the motor has been studied. To verify this proposal, we designed the induction motor controller using CAE based power simulation tool and verified the results of the proposed method by applying the reduced model. As a result, it is possible to reduce the maximum starting current and shorten the start-up time. Moreover, even if several motors are connected to one bank, it is proved that the method can be efficiently operated by using the sequential braking/starting sequence. In the case of a power system in which a large capacity electric motor such as a tunnel excavation system is driven, the results of this study are expected to be a stable and effective method for solving the start-up current problem and designing the power receiving facility.

가속된 열적 스트레스에 의한 PAI/Nano Silica 하이브리드 코일의 절연수명 추정 Estimation of Insulation Life of PAI/Nano Silica Hybrid Coil by Accelerated Thermal Stress

http://doi.org/10.5370/KIEE.2019.68.1.52

박재준(Jae-Jun Park)

In this paper, four types of insulation coils were fabricated by adding various kinds of glycols to improve the flexibility and adhesion of insulating coils in varnish dispersed with PAI/Nano Silica_15wt%. The applied voltage and frequency were 1.5kV/20kHz for accelerated life evaluation. Through the 6th temperature stress level, the cause of the insulation breakdown of the coil was ignored and only the breakdown time was measured. The Arrhenius model was chosen based on the theoretical relationship between chemical reaction rate and temperature for estimating the insulation life of the coil due to accelerated thermal stress. Three types of distributions (Weibull, Lognormal, Exponential) were selected as the relationship between thermal stress model and distribution. The average insulation lifetime was estimated under the temperature stress of four types of insulation coils through the relationship between one kind of model and three kinds of distributions.

HVDC용 LSR/Nano Silica Composites의 IPT특성 연구 Study on IPT Characteristics of LSR/Nano Silica Composites for HVDC

http://doi.org/10.5370/KIEE.2019.68.1.61

박재준(Jae-Jun Park)

Only the power is converted from AC to DC, in accordance with IEC 60587 based test method, in order to develop the LSR(Liquid Silicone Rubber) insulator material for HVDC, the experiment of Inclined Plate Tracking and Erosion Resistance was conducted. A contaminant (2.5 mS/cm: ammonium chloride) was applied at a rate of 0.3 ml/min and a voltage of ±3.5 kV, and was evaluated on the basis of 60 mA/2s. The samples were prepared by dispersing LSR/Nano silica_25wt% Composites in LSR. The erosion phenomena of surface discharge and tracking due to DC polarity and negative polarity were measured by image, leakage current maximum and thermal camera. The thermal imaging camera measured the surface temperature generated by the joule heat of the leakage current due to the drying discharge and the conductive current. After the measurement, the tracking and erosion mechanisms were evaluated for erosion weight, erosion depth and erosion length. Positive and negative polarity of LSR/Nano Silica_25wt% composite Tracking and erosion results show that positive polarity is more severe than negative polarity.

고온에서 안정한 저전력 마이크로히터 구조 최적화 연구 Study on Optimal Structure of Low Power Microheater to Remain Stability at High Temperature

http://doi.org/10.5370/KIEE.2019.68.1.69

임운현(Woonhyun Lim) ; Vijay Kondalkar(Vijay Kondalkar) ; 이기근(Keekeun Lee)

Microheaters with different structures were fabricated and compared to find an optimal configuration enhancing the performances of C2H2 gas sensor. Three temperature sensors were integrated on the surface of the insulation layer over the microheater, and resistance changes were observed to check the generated heat from the microheater. A low operating voltage of 1mV was applied to the temperature sensor to minimize any influence of thermal heat from the resistance type temperature sensor, whereas high voltages in the range between 10 and 20V were applied to the microheater. A microheater structure generating maximum heat at low voltage was determined. The generated heat was verified by the temperature sensors on the top of the Si3N4 and infrared camera. A long term stability and accuracy of the microheater were observed. The developed microheater was applied to enhance the performances of C2H2 gas sensor and successfully confirmed that the developed microheater greatly contributes to the improvement of sensitivity and selectivity of gas sensor.

0.6~6GHz 초 광대역 쿼드릿지 혼 안테나 설계 Design of 0.6~6GHz Ultra Wideband Quad-ridge Horn Antenna

http://doi.org/10.5370/KIEE.2019.68.1.77

최철진(Cheoljin Choi) ; 이문희(Moonhee Lee) ; 손태호(Taeho Son)

In this paper, a 0.6∼6GHz quad-ridge horn antenna which can be used for the antenna measurement of 5.8GHz WiFi system from lowest frequency band of mobile LTE (Long Term Evolution) is designed and implemented. The quad-ridge horn antenna has quadruple ridges of exponential function, a back-short and a cavity. Based on this structure, we design the cavity size, ridge gap and feed gap to have broadband characteristics. For implementation, the plates material of aluminum and copper are used for the horn and four ridges, respectively. And the insulator supports are used to maintain the gap between ridges. By measurement, antenna has the gain of 6.2~13.35dBi with the return loss of less than ?6dB (under VSWR 3 : 1) in the entire design band. The results of this study can be widely used to the antenna studies on the mobile communication including low frequency band of LTE, the EMI measurement and the standard calibration measurement.

Moving Least Squares 기법을 이용한 광대역 컨포멀 빔 형성 연구 A Study of Broad-band Conformal Beam Forming using Moving Least Squares Method

http://doi.org/10.5370/KIEE.2019.68.1.83

정상훈(Sang-Hoon Jung) ; 이강인(Kang-In Lee) ; 정현교(Hyun-Kyo Jung) ; 정용식(Young-Seek Chung)

In this paper, beam forming using moving least squares method (MLSM) is studied. In the previous research, the least squares method (LSM), one of the data interpolation methods, was used to determine the desired beam pattern and obtain a beam pattern that minimizes the square of the error with the desired beam pattern. However, LSM has a disadvantage in that the beam pattern can not be formed to satisfy the exact steering angle of the desired beam pattern and the peak sidelobe level (PSLL) condition. To overcome this drawback, MLSM is used for beam forming. In order to verify, the proposed method is applied in beam forming of Bezier platform array antenna which is one of conformal array antenna platform

직렬 커패시터 D/A 변환기를 갖는 저전력 축차 비교형 A/D 변환기 Low Power SAR ADC with Series Capacitor DAC

http://doi.org/10.5370/KIEE.2019.68.1.90

이정현(Jeong-Hyeon Lee) ; 진유린(Yu-Rin Jin) ; 조성익(Seong-Ik Cho)

The charge redistribution digital-to-analog converter(CR-DAC) is often used for successive approximation register analog-to-digital converter(SAR ADC) that requiring low power consumption and small circuit area. However, CR-DAC is required 2 to the power of N unit capacitors to generate reference voltage for successive approximation of the N-bit SAR ADC, and many unit capacitors occupy large circuit area and consume more power. In order to improve this problem, this paper proposes SAR ADC using series capacitor DAC. The series capacitor DAC is required 2(1+N) unit capacitors to generate reference voltage for successive approximation and charges only two capacitors of the reference generation block. Because of these structural characteristics, the SAR ADC using series capacitor DAC can reduce the power consumption and circuit area. Proposed SAR ADC was designed in CMOS 180nm process, and at 1.8V supply voltage and 500kS/s sampling rate, proposed 6-bit SAR ADC have signal-to-noise and distortion ratio(SNDR) of 36.49dB, effective number of bits(ENOB) of 5.77-bit, power consumption of 294uW.

에너지 하베스팅 무선 센서네트워크을 위한 전력기반 Pipelined-forwarding MAC프로토콜 A Power-based Pipelined-forwarding MAC Protocol for Energy Harvesting Wireless Sensor Networks

http://doi.org/10.5370/KIEE.2019.68.1.98

심규욱(Kyuwook Shim) ; 박형근(Hyung-Kun Park)

In this paper, we propose the power-based pipelined-forwarding MAC protocol which can select relay nodes according to the residual power and energy harvesting rate in EH-WSN (energy-harvesting wireless sensor networks). The proposed MAC follows a pipelined-forwarding scheme in which nodes repeatedly sleep and wake up in an EH-WSN environment and data is continuously transmitted from a high-level node to a low-level node. The sleep interval is adaptively controlled so that nodes with low energy harvesting rate can be charged sufficiently, thereby minimizing the transmission delay and increasing the network lifetime. Simulation shows that the proposed MAC protocol improves the balance of residual power and network lifetime.

잔류가스분석기의 질량 스펙트럼 검출 성능 향상을 위한 잡음제거 알고리즘 Noise Reduction Algorithm For The Detection of Fine Ion Signals in Residual Gas Analyzer

http://doi.org/10.5370/KIEE.2019.68.1.102

허경용(Gyeongyong Heo) ; 최훈(Hun Choi)

This paper proposes a method to improve the mass spectral detection performance of the residual gas analyzer. By improving the mode estimation method for setting the threshold value and improving the additive noise elimination method, it is possible to detect mass spectrums having low peak values of the threshold level difficult to distinguish from noise. Ion signal blocks for each mass index with noise removed by the improved method are effective for eliminating invalid ion signals based on the linear and quadratic fittings. The mass spectrum can be obtained from the quadratic fitted curves for the reconstructed ion signal block using only the valid ion signals. In addition, the resolution of the mass spectrum can be improved by correcting the error caused by the shift of the spectral peak position. To verify the performance of the proposed method, computer simulations were performed using real ion signals obtained from the residual gas analysis system under development. The simulation results show that the proposed method is valid.

전달정렬 함상 발사 고속 유도무기의 보정필터 설계에 대한 연구 A Study on the Design of Correction Filter for High-Speed Guided Missile Firing from Warship after Transfer Alignment

http://doi.org/10.5370/KIEE.2019.68.1.108

김천중(Cheon-Joong Kim) ; 이인섭(In-Seop Lee) ; 오주현(Ju-Hyun Oh) ; 유해성(Hae-Sung Yu) ; 박흥원(Heung-Won Park)

This paper presents the study results on the design of the correction filter to improve the azimuth error estimation of the high-speed guided missile launched from the warship after the transfer alignment. We theoretically proved that the transfer alignment performance is determined by the accuracy of the marine inertial navigation system and the observability of the attitude error state variable in the transfer alignment filter, and that most of navigation errors in high-speed guided missile are caused by azimuth error. In order to improve the azimuth estimation performance of the correction filter, the multiple adaptive estimation method and the adaptive filters adapting the measurement noise covariance or the process noise covariance are proposed. The azimuth estimation performance of the proposed adaptive filter and the existing Kalman filter are compared and analyzed each other for 8 different transfer alignment accuracy cases. As a result of comparison and analysis, it was confirmed that the adaptive filter adapting the process noise covariance has the best azimuth estimation performance. These results can be applied to the design of correction filters for high-speed guided missile.

영속도 보정 알고리즘을 이용한 전술급 관성항법장치의 자세 유지 기법 Method for Maintaining Initial Azimuth of Tactical Grade IMU by Using Zero Velocity Update Algorithm

http://doi.org/10.5370/KIEE.2019.68.1.122

김선아(Suna Kim)

This paper describe the method for maintaining initial azimuth of tactical grade IMU. The proposed method uses the zero velocity update (ZUPT) algorithm based on Kalman filter and the azimuth information previously obtained through transfer alignment. ZUPT technique can estimate and correct navigation attitude errors using the observed velocity error without the need of other sensors. Also, ZUPT combined pre-obtained azimuth information allows to maintain initial azimuth for tactical grade IMU. We verify the performance improvement of the proposed azimuth maintaining method by simulation and test.

조종날개 전개시점 경계조건을 포함한 지능화 탄약의 사거리 최대화 유도 기법 Optimal Guidance of Guided Projectile for Range Maximization with Boundary Condition on Fin Deployment Timing

http://doi.org/10.5370/KIEE.2019.68.1.129

김용재(Yongjae Kim)

In order for a gun-launched guided projectile to glide to the maximum range, when to deploy the fin and start flight with guidance and control should be considered in range optimization process. This study suggests a solution to the optimal guidance problem for flight range maximization of the flight model of a guided projectile in vertical plane considering the aerodynamic properties. After converting the nonlinear Multi-Phase Optimal Control Problem to Two-Point Boundary Value Problem, the optimized guidance command and the best fin deployment timing are calculated by the proposed numerical method. The optimization results of the multiple flight rounds with various initial velocity and launch angle indicate that determining specific launch condition incorporated with the guidance scheme is of importance in terms of mechanical energy consumption.

플러그인 하이브리드 및 전기 자동차 고압배터리 전압 측정 방법 An Approach for High Voltage Battery Voltage Sensing of Plug-In Hybrids and Battery Electric Vehicle

http://doi.org/10.5370/KIEE.2019.68.1.140

권용성(Youngsung Kwon)

This paper proposes an approach for measuring voltage of high voltage(HV) battery of plug-in hybrid electric vehicle(PHEV) and battery electric vehicle(BEV). The proposed methods use isolation resistor and isolation amplifier in order to measure high voltage which should be electrically separated from measuring circuit. In terms of practical applications their advantages and disadvantage are discussed and key design points are addressed by simulations. More importantly, the proposed methods are applicable to various applications such as on-board charger, inverter and battery management system (BMS) which are directly connected to HV battery in PHEV and BEV.

물리적 구속조건을 고려한 공대지 대전차 유도탄의 유도기법 연구 Guidance Scheme for Air-to-Ground Anti-tank Missiles Under Physical Constraints

http://doi.org/10.5370/KIEE.2019.68.1.145

박봉균(Bong-Gyun Park) ; 엄태윤(Tae-Yoon Um)

A composite guidance scheme is proposed for air-to-ground anti-tank missiles launched from an airborne platform. Long-range anti-tank missiles usually use a fiber optic line (FOL) for the datalink between an operator and the missile to obtain real-time target information and to command the missile. Also, impact angle control is used to maximize the warhead effectiveness, but it should be carefully implemented due to interference between the launch platform and the FOL. Thus, the proposed guidance scheme takes into account both impact angle and FOL constraints. Under system lag and acceleration limits, a selection method of guidance gains and calculation logic of the maximum achievable impact angle are proposed for a guideline of practical implementation. The performance of the proposed guidance scheme is investigated by nonlinear simulations with various engagement conditions.

LSTM 신경망과 Du-CNN을 융합한 적외선 방사특성 예측 및 표적과 클러터 구분을 위한 CR-DuNN 알고리듬 연구 A Study of CR-DuNN based on the LSTM and Du-CNN to Predict Infrared Target Feature and Classify Targets from the Clutters

http://doi.org/10.5370/KIEE.2019.68.1.153

이주영(Ju-Young Lee)

In this paper, we analyze the infrared feature for the small coast targets according to the surrounding environment for autonomous flight device equipped with an infrared imaging sensor and we propose Cross Duality of Neural Network (CR-DuNN) method which can classify the target and clutter in coastal environment. In coastal environment, there are various property according to diverse change of air temperature, sea temperature, deferent seasons. And small coast target have various infrared feature according to diverse change of environment. In this various environment, it is very important thing that we analyze and classify targets from the clutters to improve target detection accuracy. Thus, we propose infrared feature learning algorithm through LSTM neural network and also propose CR-DuNN algorithm that integrate LSTM prediction network with Du-CNN classification network to classify targets from the clutters.

순차 컨벡스 프로그래밍을 이용한 충돌각 제어 비행궤적 최적화 Trajectory Optimization for Impact Angle Control based on Sequential Convex Programming

http://doi.org/10.5370/KIEE.2019.68.1.159

권혁훈(Hyuck-Hoon Kwon) ; 신효섭(Hyo-Sub Shin) ; 김윤환(Yoon-Hwan Kim) ; 이동희(Dong-Hee Lee)

Due to the various engagement situations, it is very difficult to generate the optimal trajectory with several constraints. This paper investigates the sequential convex programming for the impact angle control with the additional constraint of altitude limit. Recently, the SOCP(Second-Order Cone Programming), which is one area of the convex optimization, is widely used to solve variable optimal problems because it is robust to initial values, and resolves problems quickly and reliably. The trajectory optimization problem is reconstructed as convex optimization problem using appropriate linearization and discretization. Finally, simulation results are compared with analytic result and nonlinear optimization result for verification.

롤 제어기 최적 초기화 기법 Optimal Initialization Method for Roll Control Loop

http://doi.org/10.5370/KIEE.2019.68.1.167

황익호(Ick Ho Whang) ; 박해리(Haerhee Park) ; 김형석(Hyoungseok Kim) ; 김부민(Boo Min Kim)

This paper is to consider an issue on the way to initialize the integrator in PID roll controller. A performance index including the 2 norms of roll angle and control signal is introduced to regulate initial roll angle and roll rate in an efficient way. And then we suggest the optimal value to initiate the integrator in PID roll controller by minimizing the performance index. The proposed method shows its effectiveness by showing a demonstrative design example.

표적 정보량을 최대화하는 피동 호밍궤적에 관한 고찰 A Study on Passive Homing Trajectory for Maximizing Target Information

http://doi.org/10.5370/KIEE.2019.68.1.172

나원상(Won-Sang Ra) ; 신효상(Hyo-Sang Shin) ; 정보영(Bo-Young Jung) ; 황익호(Ick-Ho Whang)

This paper deals with the problem of generating the energy optimal trajectory which is intended to enhance the target tracking performance of a passive homing missile. Noticing that the essence of passive target tracking is the range estimation problem, the target information gathered by passive measurements can be readily analyzed by introducing the range estimator designed in line-of-sight(LOS) frame. Moreover, for the linear filter structure of the suggested range estimator, the cost function associated with the target information is clearly expressed as a function of the line-of-sight rate. Based on this idea, the optimal missile trajectory maximizing the target information is obtained by solving the saddle point problem for an indefinite quadratic cost which consists of the target information and the energy. It is shown that, different from the previous heuristic approaches, the guidance command producing the optimal passive homing trajectory is produced by the modified proportional navigation guidance law whose navigation constant is determined by the weighting coefficient for target information cost.

특징점 기반 단안 영상 SLAM의 최적화 기법 및 필터링 기법 성능 분석 Performance Analysis of Optimization Method and Filtering Method for Feature-based Monocular Visual SLAM

http://doi.org/10.5370/KIEE.2019.68.1.182

전진석(Jin-Seok Jeon) ; 김효중(Hyo-Joong Kim) ; 심덕선(Duk-Sun Shim)

Autonomous mobile robots need SLAM (simultaneous localization and mapping) to look for the location and simultaneously to make the map around the location. In order to achieve visual SLAM, it is necessary to form an algorithm that detects and extracts feature points from camera images, and gets the camera pose and 3D points of the features. In this paper, we propose MPROSAC algorithm which combines MSAC and PROSAC, and compare the performance of optimization method and the filtering method for feature-based monocular visual SLAM. Sparse Bundle Adjustment (SBA) is used for the optimization method and the extended Kalman filter is used for the filtering method.

속도증분벡터를 활용한 ORB-SLAM 및 관성항법 결합 알고리즘 연구 Integrated Navigation Algorithm using Velocity Incremental Vector Approach with ORB-SLAM and Inertial Measurement

http://doi.org/10.5370/KIEE.2019.68.1.189

김연조(Yeonjo Kim) ; 손현진(Hyunjin Son) ; 이영재(Young Jae Lee) ; 성상경(Sangkyung Sung)

In recent years, visual-inertial odometry(VIO) algorithms have been extensively studied for the indoor/urban environments because it is more robust to dynamic scenes and environment changes. In this paper, we propose loosely coupled(LC) VIO algorithm that utilizes the velocity vectors from both visual odometry(VO) and inertial measurement unit(IMU) as a filter measurement of Extended Kalman filter. Our approach improves the estimation performance of a filter without adding extra sensors while maintaining simple integration framework, which treats VO as a black box. For the VO algorithm, we employed a fundamental part of the ORB-SLAM, which uses ORB features. We performed an outdoor experiment using an RGB-D camera to evaluate the accuracy of the presented algorithm. Also, we evaluated our algorithm with the public dataset to compare with other visual navigation systems.

실시간 데이터 전송이 가능한 자동 복귀형 끌림 물체 검지장치 연구 A Study on Automatic Return Dragging Detector with Real-time Data Transmission

http://doi.org/10.5370/KIEE.2019.68.1.199

전재근(Jae-Geun Jeon) ; 김동환(Dong-Hwan Kim) ; 서기범(Ki-Bum Suh) ; 김영(Young Kim)

Recently, an expansion of safety facilities has been widely applied to effectively manage the safety of train operation due to increase of the high-speed section of the general railway and the introduction of high-speed train. Accordingly, performance improvement, upgrading and high reliability of existing safety devices are required. the dragging detector, one of the safety devices, is an analogue system that consists of closed circuit with an electric current flows and operates when the closed circuit is opened by the impact of the dragging object. Such method has unreasonable problem that should be replaced after being detected. It is need to replace with an automatic return type dragging detector which is easy to maintain. In addition, it is necessary to develop a dragging detector that applicable to general railway and urban railway including high-speed railway, in accordance with the speeding up and densification of trains, although it is currently applied only to high-speed railway. In this paper, we propose an automatic return type dragging detector which has versatility and excellent maintainability with digital sensor and real time monitoring.

대용량 무선전력전송 환경 인근 메쉬구조 도전부 유도현상 특성 분석 Characteristic Analysis of Induction Phenomena in the NearbyMesh Structure Conductive Part of Large Capacity Wireless Power Transmission System

http://doi.org/10.5370/KIEE.2019.68.1.207

채동주(Dong-Ju Chae) ; 이건호(Geon-Ho Yi) ; 임현성(Hyun-Sung Lim) ; 조성구(Sung-Koo Cho)

A large-capacity wireless power system is a technology that transmits electric power of kW or more in a noncontact type. Electric cars, electric buses, and electric railways. In order to increase the power transmission efficiency, a resonance method using a frequency of kHz is applied and the efficiency is 80~90%. In this case, the loss is 10 ~ 20% other than efficiency, and corresponds to several hundreds of W to several kW in kW class wireless power transmission. 35 kW wireless feed system environment, and induced current in the nearby conductive part was measured. As a result of analysis, it was confirmed that induction phenomenon is higher as the loop configuration of the conductive part per area is dense. The increase of the induced current in the mesh loop is characterized by the density of the nearby conductive part having a permeability per unit area. The concentration of the magnetic field by the permeability is increased and the induction phenomenon causing the induction current is increased. It was confirmed that induction phenomenon increases by about 2.7 times when 9 times dense structure is formed.

초전도 코일을 이용한 DC 회로 차단기의 차단 능력 특성 Characteristics of Interruption Ability in DC Circuit Breaker using Superconducting Coil

http://doi.org/10.5370/KIEE.2019.68.1.215

정인성(In-Sung Jeong) ; 최혜원(Hye-Won Choi) ; 윤정일(Jeong-Il Youn) ; 최효상(Hyo-Sang Choi)

Development of DC interruption technology is being studied actively for enhanced DC grid reliability and stability. In this study, coil type superconductor DC circuit breaker was proposed as DC interruption. It is integration technology that combined current-limiting technique using superconductor and cut-off technique using mechanical DC circuit breaker. Superconductor was applied to the coil type. In simulation, Mayr arc model was applied to realize the arc characteristic in the mechanical DC circuit breaker. PSCAD/EMTDC had used to model and perform the simulation. To find out the protection range of coil type superconductor DCCB, the working operation have analyzed based on the rated voltage of DCCB. The results confirmed that, according to apply the limiting device, the protection range was increased in twice. Therefore, the probability of failure of interruption has lowered significantly.