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고분자 전해질 막 연료전지 응용을 위한 고성능 과불소화계 전해질 막 개발 연구 동향
최찬희,황선수,김기현,Choi, Chanhee,Hwang, Seansoo,Kim, Kihyun 한국막학회 2022 멤브레인 Vol.32 No.5
An eco-friendly energy conversion device without the emission of pollutants has gained much attention due to the rapid use of fossil fuels inducing carbon dioxide emissions ever since the first industrial revolution in the 18th century. Polymer electrolyte membrane fuel cells (PEMFCs) that can produce water during the reaction without the emission of carbon dioxide are promising devices for automotive and residential applications. As a key component of PEMFCs, polymer electrolyte membranes (PEMs) need to have high proton conductivity and physicochemical stability during the operation. Currently, perfluorinated sulfonic acid-based PEMs (PFSA-PEMs) have been commercialized and utilized in PEMFC systems. Although the PFSA-PEMs are found to meet these criteria, there is an ongoing need to improve these further, to be useful in practical PEMFC operation. In addition, the well-known drawbacks of PFSA-PEMs including low glass transition temperature and high gas crossover need to be improved. Therefore, this review focused on recent trends in the development of high-performance PFSA-PEMs in three different ways. First, control of the side chain of PFSA copolymers can effectively improve the proton conductivity and thermal stability by increasing the ion exchange capacity and polymer crystallinity. Second, the development of composite-type PFSA-PEMs is an effective way to improve proton conductivity and physical stability by incorporating organic/inorganic additives. Finally, the incorporation of porous substrates is also a promising way to develop a thin pore-filling membrane showing low membrane resistance and outstanding durability.
고주파 주입을 이용한 센서리스 제어에서의 영 전류 클램핑 효과 보상
최찬희(Chan-Hee Choi),석줄기(Jul-Ki Seck) 전력전자학회 2006 전력전자학술대회 논문집 Vol.- No.-
This paper proposes an on-line compensation strategy of the unwanted disturbance voltage due to the zero current clamping effect for high-frequency-signal-injection based sensorless control schemes. An analytical model is derived which reveals intrinsic characteristics of the zero clamping effect for the high frequency signal injection.
정밀 토크 제어를 위한 SMPM 전동기의 약자속 영역에서 자기 돌극성 추정
장주영(Ju-Young Jang),최찬희(Chan-Hee Choi),석줄기(Jul-Ki Seok) 한국조명·전기설비학회 2009 조명·전기설비학회논문지 Vol.23 No.8
본 논문에서는 고속에서 토크 제어 시 표면 부착형 전동기에 발생되는 자기 포화 현상으로 인한 돌극 현상을 분석하고 해석한다. 인덕턴스 추정을 위한 State-Filter를 고안하여 d축과 q축의 임피던스를 추정하며 추정된 d축과 q축의 임피던스 차이로 자기 포화로 인한 돌극성이 존재한다는 것을 증명한다. 또한, 약자속 영역에서 토크 제어를 수행함에 있어서 돌극성 효과를 고려한 전류제어 방법을 제안한다. 릴럭턴스 토크를 가지는 전동기 모델을 기반으로 하여 제안된 제어기는 전류 제한원에서 토크 곡선을 따라 d축과 q축의 전류를 조절한다. 제안된 전류제어의 타당성을 증명하기 위해 600[W] 상용 SMPM 전동기를 대상으로 실험을 수행하였다. The magnetic saliency effect in surface-mounted permanent-magnet (SMPM) motors on the torque control at high speeds is first presented and analyzed in this paper. The d- and q- axes impedance are measured by proposed State-Filter. Measurement of the d- and q- axes impedance difference is performed to prove the existence of the magnetic saliency. Then, the saliency effects on the torque control performance in the flux weakening region are discussed. Based on the developed motor modeling with the reluctance torque, the proposed control adjusts the d- and q-axis current toward the operating point to track the commanded torque. The feasibility of the presented idea is verified by experimental results on a commercial 600[W] SMPM motor.
김태은(Tae-Eun Kim),최찬희(Chan-Hee Choi),이해영(Hai-Young Lee) 한국조명·전기설비학회 2006 한국조명·전기설비학회 학술대회논문집 Vol.2006 No.11월
This paper proposes a novel method for control of roll speed in hot rolling process using neural network. A looper installed between the rolls in rolling process in used to keep strip tension constant. It measures inter-stand tension based on its angle to control the roll speed of the system. In this paper, the results by neural network to control inter-stand tension and roll speed are compared through simulation. The simulation results show the applicability of the proposed algorithm in the real rolling process.