SynRM 드라이브 시스템의 고성능 운전을 위한 최적 효율제어

정동화,이정철 순천대학교 2000 순천대학교 자연과학논문집 Vol.19 No.1

This paper is proposed an optimum efficiency control algorithm for a synchronous reluctance motor which minimizes the copper and iron losses. The constraint in obtaining the optimal angles is constant output torque for given operating speed. The efficiency of the motor can be improved by proposed method especially in the light load condition. It is shown that the current components which directly govern the torque production have been very well regulated by the efficiency maximized control scheme. The proposed algorithm allows the electromagnetic losses in variable speed and torque drives to be reduced while keeping good torque control dynamics. Simulation results are presented to show the validity of the proposed algorithm.

약계자 영역에서 SynRM의 MTPA를 위한 속도 센서리스 제어

정동화,이정철,이홍균 국립7개대학공동논문집간행위원회 2001 공업기술연구 Vol.1 No.-

In this paper, a new approach for the SynRM(Synchronous Reluctance Motor) control which ensures producing MTPA (Maximum Torque per Ampere) over the entire field weakening region is presented. In addition, This paper presents a speed sensorless control scheme of SynRM using flux observer. Also, by adjusting the base speed for the field weakening operation according to the flux level, the current and voltage limit, the smooth and precise transition into the field weakening operation can be achieved. The proposed scheme is verified validity through simulation.

위장질환과 Helocobacter pylori와의 상관관계

정동진,이정화,이상오,김재명,최태균 한국건강관리협회 1999 건협 Report Vol.2 No.-

상업스포츠센터의 조직문화 개념과 유형에 관한 정립

정동화 中央大學校 韓國敎育問題硏究所 2001 韓國敎育問題硏究所論文集 Vol.- No.16

It is necessary to investigate the concept and pattern of the organizational culture in order to offer basic materials inducing the profit gaining, the consumers' satisfaction. and the participation in the daily athletics by means of the understanding of the organizational culture in commercial sports centers . 1.An organization can be defined as a mediative system to accomplish its object by means of the division of labor and the hierarchy of Power, and so the culture has a microscopic meaning, which can be called the refinement of spirit. 2.The organizational culture has two opposite functions; one can be called a progressive for the systematic stability of a society; the other is a retrogressive function which can be thought a condition against an innovation. 3.For the accomplishment of the object, the organizational culture is made up of various forms of value. ideology, creature. strategy, members, circumstances, systems, rules. Consciousness, images, belief, symbols, attitudes, myth, and so on 4. The pattern of the organizational culture can be divided into two dimension; one can be said a maintenance-oriented and activity-oriented dimension; and the other intimate, progressive, conservative , reasonable dimension.

3급 부정교합 환자에서의 치료후 골격변화 양상에 관한 연구

정동화,차경석 대한치과교정학회 1996 대한치과교정학회지 Vol.26 No.3

교정치료는 치료 후의 분석이 이루어져야 그 성공여부를 평가받을 수 있다. 왜냐하면 교정치료는 환자자신의 고유한 균형을 변화시켜 또 다른 균형을 설정해가는 과정이기 때문이다. 그러나 1급이나 2급 부정교합에 비해 3급 부정교합 환자에 대한 연구는 미비하였다. 이 연구는 일반적인 교정치료시와 보정기간 중에는 어떠한 변화과정을 겪으며, 이들 중 재발양상을 나타내는 요소에 대하여 치료 전의 골격형태와 치료기간 중 변화량과의 상관관계를 알아보고자 시행하였다. 초진시의 Helleman dental age가 ⅢB이상이며 1년 6개월이상의 보정기간이 경과한 24명을 대상으로 하여 치료기간과 보정기간 중에 각항목의 변화량을 비교하고 이중 복귀현상을 나타낸 항목에 대한 상관관계를 분석하여 다음과 같은 결론을 얻었다. 1. FH plane에 대한 교합평면의 각과 하악평면의 각, 그리고 하악평면에 대한 하악 전치의 각은 치료기간중의 변화가 보정기간 중에 치료전의 상태로의 복귀현상을 나타내었으며 이중 교합평면각과 하악 전치의 치축항목은 치료기간중의 변화량과 역상관 관계를 나타내었다. 2. 치료 종료시 교합평면의 상방변위가 보정기간 중에 원래의 형태로 복귀하려는 경향을 보였으며 이는 치료기간 중에 변위량과 비례하여 나타났으나 기저골에 대한 상하악 대구치의 경사는 치료기간중의 변화량이 보정기간에 일정하게 유지되었다. 3. 보정기간 중의 하악평면각의 치료기간 중의 하악의 후하방 회전량이 클수록 감소하였다. This study was investigated the changes during treatment and retention period in the ClassⅢ malocclusion patients and explored the correlationship between factors that showed relapse tendencies and pre-treatment skeletal pattern and the changes during treatment period. Numbers of total sample were 24 and their Hellman's dental age at the start of treatment was over ⅢB and were retained at least over 1 year 5 months. The following conclusion were obtained by comparing the differences between treatment period and retention period, and after analysing the correlationship of factors that manifested relapse tendencies. 1. The angles formed by FH plane and occlusal plane, FH plane and mandibular plane, and mandibular incisor and mandibular plane changes showed rebound effect during retention period and among them occlusal plane angle and IMPA show reverse correlationship. 2. Upward displacement of the occlusal plane at the end of treatment has returning tendency, is proportional to the displacement during treatment period, but the angle between maxillary and mandibular 1st molar to its basal bone have been constantlsy maintained during the retention period. 3. Mandibular plane decrease during retention period and downward backward rotation during treatment period show correlationship.

유도전동기를 제어하기 위한 인버터의 공간벡터 퍼지제어

鄭東和,朴奎南 순천대학교 공업기술연구소 1998 工業技術硏究所論文集 Vol.12 No.-

A system with fast torque response is very beneficial in applications where direct self control(DSC) is highly desirable. The response of DSC is slower during startup and during change in command torque. Fuzzy control is used for implementation of DSC to improve its slow response. Simulation implementation of the fuzzy logic controller was carried out to verity the behavior of the controller. The simulation results with fuzzy control are compared with those of the conventional DSC. The starting flux and torque response and the responses to the step changes in command torque with fuzzy implementation show a considerable improvement over the conventional control. The steady state responses in both the cases are the same.

유도전동기의 파라미터 변동을 보상하기 위한 전압제어모델의 벡터제어

정동화 순천대학교 공업기술연구소 1992 工業技術硏究所論文集 Vol.6 No.-

For the propose of high performance operation of an induction motor, many studies on the vector control have been promoted. In the vector control scheme, in which the motor currents are controlled by the use of a motor current model, the variation of the rotor flux interlinkage and the deviation of actual torque from command torque, which are caused by the change of stator and rotor winding resistance, are large. Therefore, for high performance operation, it is necessary to compensate the variation and the deviation above. In the Voltage Model Vector Control System, where the voltages are controlled, the variation of the rotor flux-interlinkages according to the change of the rotor resistance is very small, however the deviation of the torque becomes large. In this paper, the voltage model based vector control scheme having d, q current loops eliminated harmonic components to enhance the torque performance and PWM technique to realize on-line real time control are proposed, so the full digitalization becomes possible.

컨버터로 제어되는 유도전동기 드라이브 시스템의 손실 모델링

정동화,이정철,박기태,이홍균 순천대학교 1999 순천대학교 자연과학논문집 Vol.18 No.2

An accurate loss model of induction motor drive controlled by the converter is proposed. Steady state fundamental and hamonics loss characteristics, besides the dynamics of the machine are analyzed and incorporated in the model, resulting in a new synchronous frame dynamics d-q equivalent circuit. The converter system has been modeled accurately for condition and switching losses.

유도전동기의 고성능제어를 위한 속도센서리스 벡터제어

鄭東和 순천대학교 공업기술연구소 1993 工業技術硏究所論文集 Vol.7 No.-

Recently, the elimination speed sensor has been one of the important requirement in vector control systems, because the speed sensor spoil the ruggedness and simplicity of induction motor. This paper proposes sensorless vector control for high performance of induction motor. The proposed vector control scheme is based on a rotor flux and speed control which are calculated from the stator voltage and currents with improved flux estimator. The characteristics of vector control employing stator voltage and current generally deteriorate as the speed gets lower because the calculated rotor flux depends on the stator resistance and it is difficult to calculate rotor flux at low speed of standstill. This new control system is that the stator resistance influence reduces on the torque control, and it makes possible to calculate rotor flux at low speed of standstill. These features are verified by the simulation results.

CT상의 HU 수치에 따른 상악골 전방견인 효과의 유한요소 분석

정동화 대한치과교정학회 2006 대한치과교정학회지 Vol.36 No.6

유한요소분석의 결과는 표현된 물성과 구조, 유한요소의 밀도, 그리고 경계 및 하중조건에 의존하게 된다. 상악견인장치의 사용에 있어 상악의 실제 구조와 밀도를 물성으로 반영하여 새로이 개선된 유한요소 모델과 기존의 방식을 따른 유한요소 모델을 비교하였다. 연구에서 대상이 된 환자는 13세 6개월된 남자 환자였으며 전산화단층사진 촬영으로 얻은 DICOM 영상정보를 개인용 컴퓨터로 옮긴 후 3차원 영상프로그램을 이용하여 3차원 입체영상을 제작하였다. CT상에서 Gray scale을 표현하는 수치인 Hounsfield unit (HU)값을 이용하여 24단계의 물성을 가진 모델(모델1)과 고전적인 방법에 따라 2가지의 물성만을 가진 모델(모델2)을 구성하였다. FH plane하방 45˚ 방향에서 500g의 힘으로 견인하여 다음과 같은 결론을 얻었다. 관골하 능선 후방에 있는 상악골의 부위는 전방부보다 더 넓고, 낮은 밀도를 가진 해면골로 구성되어 있었다. 따라서 같은 견인력을 적용하였음에도 24개의 물성을 가진 모델1의 제1소구치가 모델2의 제1소구치보다 전방과 하방으로의 더 많은 이동이 가능했다. 이에 대한 반응으로, 상악골은 시상면과 전두면상에서 휘어졌고, 소구치를 포함한 전방부위의 상악골이 아래 방향으로 움직이게 되었다. 고전적인 방법의 2개의 물성을 이용한 모델의 경우, 제1소구치 골 주위에서의 전하방 이동이 작게 나타났으며 상악결절부위에서는 상방으로의 이동양상을 보여 결과적으로 이 모델에서는 상악 제1대구치의 전방을 중심으로 시계방향의 회전을 보여 주었다. 따라서 물성 지정의 차이에 따라 유한 요소분석의 결과에 차이를 보였으며 HU 값을 이용했을 때 좀 더 역학적 구조가 잘 표현해 내리라 고려된다. Objective: The result of finite element analysis depends on material properties, structural expression, density of element, and boundar or loading conditions. To represent proper elastic behavior, a finite element mode1 was made using Hounsfield unit (HU) values in CT images. Methods: A 13 year 6 month old male was used as the subject. A 3 dimensional visualizing program, Mimics, was used to build a 3D object from the DICOM file which was acquired from the CT images. Model 1 was established by giving 24 material properties according to HU. Model 2 was constructed by the conventional method which provides 2 material properties. Protraction force of 500g was applied at a 45 degree downward angle from Frankfort horizontal (FH) plane. Results: Model f showed a more flexible response on the first premolar region which had more forward and downward movement of the maxillary anterior segment. Maxilla was bent on the sagittal plane and frontal plane. Model 2 revealed less movement in all directions. It moved downward on the anterior part and upward on the posterior part, which is clockwise rotation of the maxilla. Conclusion: These results signify that different outcomes of finite element analysis can occur according to the given material properties and it is recommended to use HU values for more accurate results.