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WBG 소자를 적용한 위성 전력 시스템용 LCL 회로에 관한 연구
유정상,안태영,길용만,김현배,박성우,김규동 한국반도체디스플레이기술학회 2022 반도체디스플레이기술학회지 Vol.21 No.2
In this paper, WBG semiconductor such as SiC and GaN were applied as power switches for LCL circuit that can be applied to satellite power systems and the test results of the LCL circuit are reported. P-channel MOSFET and N-channel MOSFET, which were generally used in the conventional LCL circuit, were applied together to expand the utility of the test results. The design and stability evaluation were performed using a Micro Cap circuit simulation program. For the test circuit, a module using each switch was manufactured, and a total of 5 modules were manufactured and the steady state and transient state characteristics were compared. From the experimental results, the LCL circuit for power supply of the satellite power system constructed in this paper satisfied the constant current and constant voltage conditions under various operating conditions. The P-channel MOSFET showed the lowest efficiency characteristics, and the three N-channel switches of Si, SiC and GaN showed relatively high efficiency characteristics of up to 99.05% or more. In conclusion, it was verified that the on-resistor of the switch had a direct effect on the efficiency and loss characteristics.
토템폴 브릿지리스 PFC의 내부 손실 분석과 병렬 스위치를 사용한 효율 개선에 관한 연구
유정상,길용만,유승협,안태영,Yoo, Jeong Sang,Gil, Yong Man,Yu, Seung Hyup,Ahn, Tae Young 한국반도체디스플레이기술학회 2020 반도체디스플레이기술학회지 Vol.19 No.4
In this paper, a generalized efficiency equation was proposed to estimate the internal loss of the SMPS (switched-mode power supply) with 3 variables. The first variable was an internal loss not related to the load current such as auxiliary power, the second was a loss proportional to the current such as diode loss, and the third was a loss proportional to square of the current such as conduction loss. Especially, theoretical internal losses of the totem pole bridgeless PFC which is widely used for high efficiency SMPS were expressed as output function to compare generalized efficiency equation. In addition, in order to reduce the conduction loss of the switch, when a multiple switch were paralleled, the correlation with the efficiency was analyzed and shown as a graph. In order to confirm the degree of the parallel switch structure on the efficiency improvement, a 2kW class totem pole bridgeless PFC was constructed and the effectiveness of the analysis was confirmed by comparing the generalized efficiency equation and theoretical loss analysis results with experimental data.
내부 손실 저항이 있는 정상상태 모델을 이용한 LLC 공진형 하프 브리지 dc-dc컨버터의 최적 설계에 관한 연구
유정상,안태영,Yoo, Jeong Sang,Ahn, Tae Young 한국반도체디스플레이기술학회 2022 반도체디스플레이기술학회지 Vol.21 No.3
In this paper, the optimal design and circuit simulation verification results of an LLC resonant half-bridge dc-dc converter using a steady-state model with internal loss resistance are reported. Above all, the input/output voltage gain and frequency characteristic equations in the steady-state were derived by reflecting the internal loss resistance in the equivalent circuit. Based on the results, an LLC resonant half-bridge dc-dc converter with an input voltage of 360-420V, an output voltage of 54V, and a maximum power of 3kW was designed, and to verify the design, the PSIM circuit simulation was executed to compare and analyze the result. In particular, the operating range of the converter could be drawn from the frequency characteristic graph of the voltage gain, and when the converter was operated under light and maximum load conditions, it was confirmed that similar results were obtained by comparing simulation results and calculation results in the switching frequency characteristic graph. In addition, the change of the switching frequency with respect to the load current at each input voltage was compared with the calculated value and the simulation result. As a result, it was possible to confirm the usefulness of the analysis result reflecting the internal loss resistance proposed in this paper and the process of the optimal design.
DAB 컨버터용 전력 변압기의 누설 인덕턴스를 포함한 내부 전력 손실 분석에 관한 연구
유정상,안태영,길용만 한국반도체디스플레이기술학회 2022 반도체디스플레이기술학회지 Vol.21 No.2
In this paper, a power loss analysis technique of a high-frequency transformer of a bidirectional DAB (Dual Active Bridge) converter is reported. To miniaturize the transformer of the dual active bridge converter, a resonant inductor was designed with an air gap included low-coupled rate state core to combine leakage inductor with the resonant inductor which is required for soft-switching. In this paper, leakage inductance and magnetizing inductance, core material, type of winding and winding method are included in the dual active bridge transformer loss analysis process to enable optimal design at the initial design stage. Transformer loss analysis for dual active bridge with a switching frequency of 200 kHz and maximum output of 5 kW was executed, and elements necessary for design based on the number of turns on the primary side were graphed while maintaining the transformer turns ratio and window area. In particular, it was possible to determine the optimal number of turns and thickness of the transformer, and ultimately, the total loss of the transformer could be estimated.
유정상 경원전문대학 1998 論文集 Vol.20 No.-
Recently, PM analysis is often utilized for lessening the loss time of machines and improving product quality in TPM activities. However, industries have experienced many cases that the defects are not decreasing to the intended level. The reason of these results is that PM analysis is deductive method only based on elementary principles and a fundamental law. In this research, the combination of PM analysis and SQC(design of experiment) method is presented. This combination method will provide zero defects and level-up of technique for many industries.
Fuzzy Goal Programming을 이용한 최적 검사 정책
유정상 한국산업경영시스템학회 1995 한국산업경영시스템학회지 Vol.18 No.34
In this research, a mathematical programming model is developed for the economic modeling of sampling plans based on two evaluation criteria : the outgoing quality and the average total inspection cost A fuzzy goal programming model and its solution procedure are proposed for the managers whose management objectives on the two evaluation criteria are not rigorous. To study the sensitivity of quality characteristic dependence on the resulting inspection plans, a numerical example is solved several times for a dependent model.
유정상,권희철 한국경영공학회 2008 한국경영공학회지 Vol.13 No.3
Most parking control systems provide automatic toll collection services. The current parking control systems use RFID and vehicle plate recognition method to identify the cars that enter into and go out from the parking area. So far, the current systems have problems that a driver should search an available parking space once entering into, and do not have any solution to solve air pollution, fires, burglars, hit-and-run accidents. Also, the patrol officers who operate the systems are required to monitor the parking area consistently. It is necessary that intelligent parking control systems are equipped in the park area to solve these problems. Thus, this paper presents intelligent recognition architecture providing that context interpreter infers the inference results from context information acquired from video cameras and sensors of parking control system in parking area. The test program implemented by java language is offered as a prototype application.
20W급 보조전원용 다출력 QR 플라이백 컨버터의 출력전압 안정화에 관한 연구
유정상,길용만,김현배,안태영,Yoo, Jeong Sang,Gil, Yong Man,Kim, Hyun Bae,Ahn, Tae Young 한국반도체디스플레이기술학회 2021 반도체디스플레이기술학회지 Vol.20 No.3
In this paper, a 20W class multi-output QR flyback converter for auxiliary power supply was designed to stabilize 4 output voltages, and the efficiency and load characteristics were compared and analyzed. It was checked if each output affects other output characteristics through experiment. As a result, the experimental circuit reached a high efficiency of 82.5% or more at a load power of over 20W, and the maximum power loss was 2.6W. Consequently, it was confirmed that all of 4 output voltages of the multi-output QR flyback converter constructed in this paper were stabilized within 0.5% in full-load range, and each output was independently controlled in an electrically isolated state.