Development of a Switched Reluctance Motor-based Electric AC Compressor Drive for HEV/EV Applications

Jaehyuck Kim,Yong-hoe Jeong,Yong-Hee Jeon,Jun-Ho Kang,Seunghun Lee,Jang-Yeop Park 한국자기학회 2014 Journal of Magnetics Vol.19 No.3

This paper discusses the development of a 3.5 kW switched reluctance motor (SRM)-based electric air-conditioning (AC) compressor, focusing primarily on the design aspects of the SRM and the integrated controller. In addition to the increased price of rare-earth magnets, SRM’s operation capability at high speed and high temperature makes the SRM a viable alternative to the permanent magnet motor for electrically driven automotive air conditioning compressors. A compact and energy efficient scroll compressor is designed and constructed. Two feasible SRM topologies are considered, in terms of efficiency, torque ripple, and acoustic noise. Compact drive electronics are designed and employed to drive the SRM-based compressor. The static and dynamic performance is validated by simulation and experiment.

배출가스 저감을 위한 인젝터 연료분사 편차보정 구동반도체 개발

DooJin Jang,JiHaeng Lee,JaeHyuck Woo 대한전자공학회 2019 대한전자공학회 학술대회 Vol.2019 No.6

The GDI(Gasoline Direct Injection) engine needs to reduce emissions because emission standards has been strengthened recently(Eg. EURO6). For compling with new emission standards, the multi-injection of fuel method is commonly used in the GDI engine. However, a short injection time causes deviation of the fuel injection quantity and this deviation reduces the efficiency of fine dust emission. This paper suggest a new fuel injector driver IC which reduces fine dust emissions through a new injector deviation compensation algorithm. The main designed concept is monitoring injector closing time and compensating the quantity of fuel injection by the proposed GDI injector driver IC.

스마트폰 기반의 QRCode를 활용한 정보제공 시스템

이재혁(Jaehyuck Lee),박선호(Sunho Park),김대균(Daegyun Kim),임소라(Sora Lim),장용희(Yonghee Jang),권용진(Yongjin Kwon) 한국통신학회 2011 한국통신학회 학술대회논문집 Vol.2011 No.2

Plasmonic- and dielectric-based structural coloring: from fundamentals to practical applications

이태준,Jang Jaehyuck,정헌영,노준석 나노기술연구협의회 2018 Nano Convergence Vol.5 No.1

Structural coloring is production of color by surfaces that have microstructure fine enough to interfere with visible light; this phenomenon provides a novel paradigm for color printing. Plasmonic color is an emergent property of the interaction between light and metallic surfaces. This phenomenon can surpass the diffraction limit and achieve near unlimited lifetime. We categorize plasmonic color filters according to their designs (hole, rod, metal–insulator–metal, grating), and also describe structures supported by Mie resonance. We discuss the principles, and the merits and demerits of each color filter. We also discuss a new concept of color filters with tunability and reconfigurability, which enable printing of structural color to yield dynamic coloring at will. Approaches for dynamic coloring are classified as liquid crystal, chemical transition and mechanical deformation. At the end of review, we highlight a scale-up of fabrication methods, including nanoimprinting, self-assembly and laser-induced process that may enable real-world application of structural coloring.

FFT-Based Position Estimation in Switched Reluctance Motor Drives

Keunsoo Ha,Jaehyuck Kim,Jang Young Choi 한국자기학회 2014 Journal of Magnetics Vol.19 No.1

Position estimation that uses only active phase voltage and current is presented, to perform high accuracy position sensorless control of a SRM drive. By extracting the amplitude of the first switching harmonic terms of phase voltage and current for a PWM period through Fast Fourier Transform (FFT), the flux-linkage and position are estimated without external hardware circuitry, such as a modulator and demodulator, which result in increased cost, as well as large position estimation error, produced when the motional back EMF is ignored near zero speed. A two-phase SRM drive system, consisting of an asymmetrical converter and a conventional closed-loop PI current controller, is utilized to validate the performance of the proposed position estimation scheme in comprehensive operating conditions. It is shown that the estimated values very closely track the actual values, in dynamic simulations and experiments.

A 1.4-m <tex> $\Omega$</tex> -Sensitivity 94-dB Dynamic-Range Electrical Impedance Tomography SoC and 48-Channel Hub-SoC for 3-D Lung Ventilation Monitoring System

Kim, Minseo,Jang, Jaeeun,Kim, Hyunki,Lee, Jihee,Lee, Jaehyuck,Lee, Jiwon,Lee, Kyoung-Rog,Kim, Kwantae,Lee, Yongsu,Lee, Kyuho Jason,Yoo, Hoi-Jun IEEE 2017 IEEE journal of solid-state circuits Vol.52 No.11

<P>A wearable electrical impedance tomography (EIT) system is proposed for the portable real-time 3-D lung ventilation monitoring. It consists of two types of SoCs, active electrode (AE)-SoC and Hub-SoC, mounted on wearable belts. The 48-channel AE-SoCs are integrated on flexible printed circuit board belt, and Hub-SoC is integrated in the hub module which performs data gathering and wireless communication between an external imaging device. To get high accuracy under the variation of conductivity, the dual-mode current stimulator provides the optimal frequency for time difference-EIT and frequency difference-EIT with simultaneous 4 k-128 kHz impedance sensing. A wide dynamic range instruments amplifier is proposed to provide 94 dB of wide dynamic range impedance sensing. In addition, the 48-channel AE system with the dedicated communication and calibration is implemented to achieve 1.4-m Omega sensitivity of impedance difference in the in vivo environment. The AE-/Hub-SoCs occupy 3.2 and 1.3 mm2in 65-nm CMOS technology and consume 124 mu W and 1.1 mW with 1.2 V supply, respectively. As a result, EIT images are reconstructed with 90% of accuracy, and up to 10 frames/s real-time 3-D lung images are successfully displayed.</P>

뇌영상 정보추출 응용 분석을 위한 융합 자원관리 시스템

윤준원(JunWeon Yoon),곽재혁(JaeHyuck Kwak),함재균(JaeGyoon Hahm),장지훈(JiHoon Jang),박찬열(ChanYeol Park) 한국정보기술학회 2012 한국정보기술학회논문지 Vol.10 No.10

시민의 복지태도와 나눔행동에 관한 연구: 기부와 자원봉사 참여를 중심으로

이종화(Jonghwa Lee),장재혁(Jaehyuck Jang),한민희(Min Hee Han) 연세대학교 사회복지연구소 2019 한국사회복지조사연구 Vol.60 No.-

본 연구의 목적은 시민의 복지태도가 나눔행동에 미치는 영향력을 확인하는 것이다. 이를 위해 서울시와 서울연구원이 서울시 거주 3,019가구를 조사한 2015 서울복지실태조사 데이터를 활용해 시민들이 가진 4가지 복지태도 : 성장과 분배, 선택적 복지와 보편적 복지, 복지지출에 대한 개인과 정부의 책임, 정부복지정책 신뢰수준이 기부와 자원봉사 참여에 미치는 영향을 확인하였다. 분석방 법으로는 두 개의 이항종속변수 사이에 존재할 수 있는 상호의존성을 반영해 효율적인 추정을을 가능하게 해주는 이변량 프로빗 모형을 사용하였다. 연구결과 성장보다 분배를 중요하게 인식할수 록, 정부복지정책에 대한 신뢰가 높을수록 기부에 적극적으로 참여하였고, 복지지출에 대한 정부의 책임을 중요하게 인식할수록 기부에 소극적인 것으로 나타났다. 그리고, 보편적 복지 정책에 대한 중요성 중요하게 인식할수록 자원봉사 참여에 소극적인 것으로 나타났다. 본 연구는 연구의 성과가 부족한 복지에 대한 개인 인식과 나눔 행동 사이의 관계에 대해 실증적인 분석을 하였고, 기부와 자원봉사 행동에 대한 상호의존성을 반영할 수 있는 분석방법을 소개했다는 점에서 의의를 갖는다. The purpose of the study is to identify the influence that the citizen’s attitude of welfare exerts on philanthropic behaviors. Specifically, the study has identified the influences that the citizen’s attitude on the four things, that is, growth and distribution, targeted welfare and universal welfare, the responsibility for welfare expenses, and the trust in the governmental welfare policy, exert on donations and participation in volunteer work. For this purpose, the study used the data from the 2015 Seoul Welfare Survey which was conducted with 3,019 households in Seoul. And for its analytical method, the study employed Bivariate Probit model which enables efficient estimation by reflecting the interdependence that may exist between the two binomial dependent variables. The study showed that people who consider welfare distribution more importantly than economic growth and those who put greater trust in the governmental welfare policy more actively participated in donation, and that those who more strongly believe the governmental responsibility for welfare were more passive in participating in donation, and that those who more strongly believe the importance of universal welfare policy were more passive in participating in volunteer activities. This study has performed an empirical analysis on the relationship between the public perception of welfare and philanthropic behaviors and is significant in that it has introduced a new analytical method that can reflect the interdependence between donation and volunteer participation.

비선형 잠재성장모형을 활용한 대학생의 자아효능감과 행복에 관한 종단연구

원효헌 ( Hyoheon Won ),장재혁 ( Jaehyuck Jang ),서원석 ( Wonsuk Suh ) 인문사회 21 2023 인문사회 21 Vol.14 No.1

연구 목적: 본 연구는 고등학생시기부터 대학생시기까지 자아효능감과 행복의 변화 궤적을 살펴보고 종단적 관련성을 규명하는데 목적을 두었다. 연구 방법: 이를 위해 한국교육고용패널Ⅱ(KEEPⅡ)의 1차년도부터 4차년도까지 7,307명의 데이터를 활용하였다. 연구 내용: 도출된 연구결과 첫째, 대학생의 자아효능감은 무변화, 선형변화, 비선형변화를 가정한 모형 중 비선형변화를 가정한 모형이 자아효능감의 변화궤적을 가장 적합하게 설명하였다. 둘째, 대학생의 행복은 무변화, 선형변화, 비선형변화를 가정한 모형 중 비선형변화를 가정한 모형이 행복의 변화궤적을 적절하게 설명하였다. 셋째, 고2시기의 자아효능감이 높을수록 고2시기 행복과 비선형변화에 정적으로 유의미한 영향을 미쳤으며, 자아효능감의 선형변화는 행복의 선형변화에 정적인 영향을 미치는 것으로 나타났다. 결론 및 제언: 도출한 연구결과를 근간으로 본 연구는 자아효능감이 행복에 미치는 종단적 효과를 규명하는데 의의가 있었으며, 시기별로 자아효능감의 양상을 파악해 대학생의 행복증진을 위한 정책적 기초자료가 되길 기대한다. The purpose of this study was to examine the trajectory of changes in self-efficacy and happiness from high school to college and to investigate the longitudinal relationship. For this purpose, 7,307 university’s students from the 1st to 4th years of the Korea Education and Employment Panel Ⅱ (KEEPⅡ) were used. Research results are as following. First, among the models that assumed the self-efficacy of university's students explained the change trajectory of self-efficacy most appropriately in the model assuming non-linear change. Second, among the models that assumed non-linear change properly explained the change trajectory of happiness for college students. Third, the higher the self-efficacy in the second year of high school, the more significant it had a positive effect on happiness and non-linear changes in the second year of high school. The linear change in self-efficacy had a positive effect on the linear change of happiness. Based on the research results, this study was meaningful in examining the longitudinal effects of self-efficacy on happiness, and it is expected that it will become a basic policy data for improving the happiness of college students by identifying the aspects of self-efficacy.

Self-Assembly of Silver Nanowire Ring Structures Driven by the Compressive Force of a Liquid Droplet

Seong, Baekhoon,Park, Hyun Sung,Chae, Ilkyeong,Lee, Hyungdong,Wang, Xiaofeng,Jang, Hyung-Seok,Jung, Jaehyuck,Lee, Changgu,Lin, Liwei,Byun, Doyoung American Chemical Society 2017 Langmuir Vol.33 No.14

<P>In a nanowire dispersed in liquid droplets, the interplay between the surface tension of the liquid and the elasticity of the nanowire determines the final morphology of the bent or buckled nanowire. Here, we investigate the fabrication of a silver nanowire ring generated as the nanowire encapsulated inside of fine droplets. We used a hybrid aerodynamic and electrostatic atomization method to ensure the generation of droplets with scalable size in the necessary regime for ring formation. We analytically calculate the compressive force of the droplet driven by surface tension as the key mechanism for the self-assembly of ring structures. Thus, for potential large-scale manufacturing, the droplet size provides a convenient parameter to control the realization of ring structures from nanowires.</P>