IPMSM Design for Sensorless Control Considering Magnetic Neutral Point Shift According to Magnetic Saturation

Choi, JaeWan,Seol, Hyun-Soo,Lee, Ju The Korean Institute of Electrical Engineers 2018 Journal of Electrical Engineering & Technology Vol.13 No.2

In this paper, interior permanent magnet synchronous motor (IPMSM) design for sensorless drive, considering magnetic neutral point shift according to magnetic saturation, has been proposed. Sensorless control was divided into a method based on inductance and a method based on back induced voltage. Because induced voltage is very small at zero or low speed, error in rotor initial position estimation may occur. Using the ratio of saliency addresses this problem. When using high-frequency injections at low speed, the rotor's initial position is estimated at the smallest portion of the inductance. IPMSM has the minimum inductance at the d-axis. However, if magnetic saturation leads to magnetic neutral point variation, following the load current change, there is a change in the minimum point of inductance. In this case, it can lead to failure of initial rotor position estimation. As a result, it is essential that the blocking design has an inductance minimum point shift. As such, in this study, an IPMSM design method, by blocking magnetic neutral point change, has been proposed. After determining the inductance profile based on the finite element analysis (FEA), the results of proposed method were verified.

Brush-Shaped ZnO Heteronanorods Synthesized Using Thermal-Assisted Pulsed Laser Deposition

Choi, Jaewan,Ji, Hyunjin,Tambunan, Octolia Togibasa,Hwang, In-Sung,Woo, Hyung-Sik,Lee, Jong-Heun,Lee, Bo Wha,Liu, Chunli,Rhee, Seuk Joo,Jung, Chang Uk,Kim, Gyu-Tae American Chemical Society 2011 ACS APPLIED MATERIALS & INTERFACES Vol.3 No.12

<P>Brush-shaped ZnO heteronanostructures were synthesized using a newly designed thermal-assisted pulsed laser deposition (T-PLD) system that combines the advantages of pulsed laser deposition (PLD) and a hot furnace system. Branched ZnO nanostructures were successfully grown onto CVD-grown backbone nanowires by T-PLD. Although ZnO growth at 300 °C resulted in core–shell structures, brush-shaped hierarchical nanostructures were formed at 500–600 °C. Materials properties were studied via photoluminescence (PL), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) characterizations. The enhanced photocurrent of a SnO<SUB>2</SUB>–ZnO heterostructures device by irradiation with 365 nm wavelength ultraviolet (UV) light was also investigated by the current–voltage characteristics.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2011/aamick.2011.3.issue-12/am201106v/production/images/medium/am-2011-01106v_0008.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/am201106v'>ACS Electronic Supporting Info</A></P>

Scientific Analysis on the Accessory Ornament of Woolen Tapestry Curtain in Seoul Museum of Craft Art

Choi, Jaewan,Lee, Jangjon,An, Boyeon The Korean Society Of Conservation Science For Cul 2021 보존과학회지 Vol.37 No.4

Woolen tapestry curtains possessed by the Seoul Museum of Craft Art were used to hung on the wall or used for carpets in the winter season in the late Joseon dynasty. Since similar artifacts were only used for the curtain as functional aspects, woolen tapestry curtains were a rare case. In this study, scientific analysis on the accessory ornament of woolen tapestry curtains such as components of metal accessories and frame bar were conducted with the microscope, p-XRF, and SEM. Result of frame bar pigments, organic pigments such as ink stick were likely been used in woolen tapestry curtain 1. In woolen tapestry 2, lead red (Minium) was used in the frame bar. The result of metal parts, copper, and zinc were analyzed by p-XRF. This suggests that metal accessories were crafted using brass. Frame bar of woolen tapestry curtain 2 was made of soft pine (Pinus spp.) analyzed with the scanning electron microscope. Artifacts like woolen tapestry curtains are rare in Korea and scientific analysis databases were scarce, so it is important to construct components analysis data of woolen tapestry curtains. It is expected that additional scientific analysis and interpretation on the artifact's crafting technique can be merged with the analytical data gathered in this study to be utilized on the conservation and restoration of not only woolen curtains but curtain artifacts of the late Joseon dynasty in general.

A New Adaptive Component-Substitution-Based Satellite Image Fusion by Using Partial Replacement

Jaewan Choi,Kiyun Yu,Yongil Kim IEEE 2011 IEEE transactions on geoscience and remote sensing Vol.49 No.1

<P>Preservation of spectral information and enhancement of spatial resolution are regarded as important issues in remote sensing satellite image fusion. In previous research, various algorithms have been proposed. Although they have been successful, there are still some margins of spatial and spectral quality that can be improved. In addition, a new method that can be used for various types of sensors is required. In this paper, a new adaptive fusion method based on component substitution is proposed to merge a high-spatial-resolution panchromatic (PAN) image with a multispectral image. This method generates high-/low-resolution synthetic component images by partial replacement and uses statistical ratio-based high-frequency injection. Various remote sensing satellite images, such as IKONOS-2, QuickBird, LANDSAT ETM+, and SPOT-5, were employed in the evaluation. Experiments showed that this approach can resolve spectral distortion problems and successfully conserve the spatial information of a PAN image. Thus, the fused image obtained from the proposed method gave higher fusion quality than the images from some other methods. In addition, the proposed method worked efficiently with the different sensors considered in the evaluation.</P>

Hybrid Pansharpening Algorithm for High Spatial Resolution Satellite Imagery to Improve Spatial Quality

Jaewan Choi,Junho Yeom,Anjin Chang,Younggi Byun,Yongil Kim IEEE 2013 IEEE geoscience and remote sensing letters Vol.10 No.3

<P>Most pansharpened images from existing algorithms are apt to present a tradeoff relationship between the spectral preservation and the spatial enhancement. In this letter, we developed a hybrid pansharpening algorithm based on primary and secondary high-frequency information injection to efficiently improve the spatial quality of the pansharpened image. The injected high-frequency information in our algorithm is composed of two types of data, i.e., the difference between panchromatic and intensity images, and the Laplacian filtered image of high-frequency information. The extracted high frequencies are injected by the multispectral image using the local adaptive fusion parameter and postprocessing of the fusion parameter. In the experiments using various satellite images, our results show better spatial quality than those of other fusion algorithms while maintaining as much spectral information as possible.</P>

IPMSM Design for Sensorless Control Considering Magnetic Neutral Point Shift According to Magnetic Saturation

JaeWan Choi,Hyun-Soo Seol,Ju Lee 대한전기학회 2018 Journal of Electrical Engineering & Technology Vol.13 No.2

In this paper, interior permanent magnet synchronous motor (IPMSM) design for sensorless drive, considering magnetic neutral point shift according to magnetic saturation, has been proposed. Sensorless control was divided into a method based on inductance and a method based on back induced voltage. Because induced voltage is very small at zero or low speed, error in rotor initial position estimation may occur. Using the ratio of saliency addresses this problem. When using highfrequency injections at low speed, the rotor’s initial position is estimated at the smallest portion of the inductance. IPMSM has the minimum inductance at the d-axis. However, if magnetic saturation leads to magnetic neutral point variation, following the load current change, there is a change in the minimum point of inductance. In this case, it can lead to failure of initial rotor position estimation. As a result, it is essential that the blocking design has an inductance minimum point shift. As such, in this study, an IPMSM design method, by blocking magnetic neutral point change, has been proposed. After determining the inductance profile based on the finite element analysis (FEA), the results of proposed method were verified.

UAV 기반 다중분광 영상을 활용한 주제도 생성 기법

최재완 ( Jaewan Choi ) 충북대학교 건설기술연구소 2015 建設技術論文集 Vol.34 No.2

디지털 카메라, 다중분광 센서, 헨, IMU 등이 탑재된 UAV는 디지털지도 매핑, 지형공간정보생성, 지형 모니터링 등의 다양한 응용분야에 사용될 수 있다. 특히, UAV의 다중분광센서에 의하여 획득된 고해상도 영상은 토지피복분류를 기반으로 하는 주제도 생성에 효과적일 수 있다. 본 연구에서는 고정익 UAV 기반의 다중분광 영상을 이용하여 정사영상 및 DSM을 생성하였다. 전 처리분야에서는 영상분할기법이 적용되었다. 최종적으로, 객체기반의 토지피복 분류를 위하여 입력자료가 추가된영상 레이어에 대하여 SVM 기법이 적용되었다. 실험결과, NDVI와 nDSM을 이용한 객체기반의 분류결과가 전통적인 분류결과와 비교하여 높은 분류 정확도를 나타냈다. 특히, NDVI와 nDSM을 이용한 객체기반의 분류결과는 타 토지피복개체로부터 인공구조물과 식생을 효과적으로 구분하였다. UAV(Unmanned Aerial Vehicle) mounting digital camera, multispectral sensor, GPS(Global Positioning System) and IMU(Inertial Measurement Unit) can be used to many applications, such as digital mapping, geo-spatial information generation, and land monitoring. Especially, High resolution images by multispectral sensor of UAV are effective to generate thematic map based on land cover classification. In this study, orthoimage and DSM (Digital Surface Model) were generated using multispectral image based on fixed-wing UAV. In pre-processing, image segmentation was conducted. Finally, SVM (Support Vector Machine) algorithm was applied to layer-slacked data for object-based land cover classification. In the experiments, object-based classification result by using NDVI (Normalized Difference Vegetation Index) and nDSM (normalized DSM) represented high classification accuracy, compared to traditional classification results. Especially, object-based classification based on NDVI and nDSM could discriminate man-made objets and trees from another land-cover objects.

자기 포화를 고려한 센서리스 제어용 IPMSM 설계

최재완(JaeWan Choi),설현수(Hyun-Soo Seol),정동훈(Dong-Hoon Jung),박예지(YeJi Park),이주(Ju Lee) 대한전기학회 2017 대한전기학회 학술대회 논문집 Vol.2017 No.7

Graphic User Interface와 칸딘스키 조형의식과의 상관성 연구

최재완(Choi Jaewan),하중규(Ha Joonggyu) 한국디지털디자인학회 2008 디지털디자인학연구 Vol.8 No.1

User Interface는 제품사용을 원활히 지원하는 제품언어로서 사용방법을 집약시킨 것이므로 제품과 사용자의 입장에서는 하드웨어적인 문제가 아니라 소프트웨어적인 요소가 중요하게 대두된다. 따라서 사용상의 운용언어 (Operating Language)는 Text보다는 Graphic이다. 인지와 인식이 쉽고 대중화와 세계화에 있어서 중요 요소라고 할 수 있다. 오늘날 인터페이스의 연구는 IT의 발달에 따라 많은 성과를 가져 왔다. 그러나 인터페이스 그래픽 언어의 조형성 검토는 미미한 수준에 머물러 왔다. 기능성·사용성·심미성의 인터페이스 속성 인자들 중에서 심미성은 조형요소에 근원하고 있다. 본 연구에서는 인터페이스 그래픽의 조형성을 탐색할 목적으로 바우하우스시기에 기하학적 조형을 구사한 칸딘스키를 주목하여 그의 작품에 나타난 조형언어가 인터페이스 조형성과 어떠한 상관관계를 갖는지를 살펴보고 인터페이스 속성 인자인 심미성의 근원을 탐색하였다. 칸딘스키의 기초조형 이념은 현재 Graphic User Interface의 지향점과 유사한 점이 많은 동시에 Graphical symbol의 조형 구성 원리와 유사한 것이 많다. 나아가 칸딘스키의 조형이념의 목표가 제품의 형태구성 원리뿐만 Graphic User Interface의 시각언어 구성에 대한 조형화에도 영향을 주었다고 할 수 있다. User Interface is the Language of product usage in which the user's interaction focusing on not hardware problems but software problems. Therefore operating language of the usage is graphical symbol language better than text. The Operating Language for use is Graphic which is easy to recognize and an important factor in popularization and globalization. However the formation about interface language is not being examined with activity. In this original research paper was studied about Bauhaus age considered as the significant Graphic Formative period searched the interface formation of the basic design education directed by Kandinsky. His basic design education is similar to the Graphical design factor brought out in the graphic user interface. Also it affected not only a product shape but also the graphical symbol design of interface

전기-기계식 구동기의 제어를 위한 외란 관측기와 시간 지연제어기 설계 및 비교분석

최재완(Jaewan Choi),김민유(Minyu Kim),최영훈(Younghoon Choi) 항공우주시스템공학회 2023 항공우주시스템공학회 학술대회 발표집 Vol.2023 No.05

최근 친환경 및 경제성의 이유로 항공 및 우주 산업 등 다양한 분야에서 전기-기계식 구동기(Electro-Mechanical Actuator, EMA)에 대한 연구 개발이 활발히 진행되고 있다. 본 논문에서는 EMA 기반 로터 블레이드 피치각 제어시스템의 불확실성을 고려하기 위해 외란관측기와 시간 지연제어기를 설계한다. 외란 관측기 기반 제어기법은 앞먹임 제어를 활용하여 기존의 되먹임 제어 기반 기법보다 더 빠르고 효과적으로 외란의 영향을 줄일 수 있는 장점이 있다. 시간 지연제어기는 이전 상태값을 통해 효과적으로 시스템의 불확실성을 제거할 수 있는 장점이 있다. 본 논문에서는 수치 시뮬레이션을 통해 설계한 제어기의 제어 성능을 비교 분석한다.