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진준우,염차경,구민영,문병인,최국진,최혜영 한국유방암학회 2008 Journal of breast cancer Vol.11 No.3
Purpose: Accurate preoperative assessment of breast cancer is important to determine the extent of disease and the plan for surgery. The purpose of this study was to evaluate the efficacy of preoperative breast MRI in breast cancer patients. Methods: Between January 2001 and October 2007, 457 consecutive patients who had undergone surgical treatment for breast cancer were retrospectively studied. We compared 303 patients from the non-preoperative MRI group (group A) to 154 patients from the preoperative MRI group (group B). The impact of preoperative MRI was evaluated for each patient with regard to changes in therapeutic intervention. Results: MRI alone revealed 17 new lesions. The results of the MRI led to a change in 9.1% of the planned surgical procedures. Tumor size was more accurately defined in patients undergoing MRI than in those undergoing ultrasound imaging. Conclusion: Breast MRI could be recommended as a preoperative diagnostic procedure in patients allocated to receive breast conservation surgery, because MRI may reveal unsuspected multifocal or multicentric tumors or carcinoma infiltrations and may result in changes in therapy.
EV Traction용 매입형 영구자석 동기전동기의 집중권/분포권에 따른 특성 비교
진준우(Jun-Woo Chin),박민로(Min-Ro Park),김해중(Hae-Joong Kim),홍정표(Jung-Pyo Hong) 한국자동차공학회 2015 한국자동차공학회 부문종합 학술대회 Vol.2015 No.5
This paper deals with the characteristic of interior permanent magnet synchronous motor(IPMSM) for traction of electric vehicle(EV). EV is an excellent alternatve for conventional inner combustion engine(ICE) vehicle. As high torque and wide operation range are essential for EV traction motor, IPMSM is suitable for EV traction application. Concentrated and distributed winding differ in characteristics of interior permanent magnet motor. Thus, this paper compares electric characteristics of concentrated and distributed winding. The finite element analysis(FEA) is performed both for concentrated winding model and distributed winding model to calculate characteristics such as torque, power, losses and efficiency.
고정투자율법을 이용한 고조파 전류 입력 철손 해석 방법
유준열,진준우,임명섭 한국자기학회 2021 한국자기학회 학술연구발표회 논문개요집 Vol.31 No.2
최근 산업에서 많이 사용되는 전기 모터의 운전 영역이 넓어짐에 따라 철손 예측에 대한 관심이 늘어나고 있다. 하지만, 고속 영역에서 정확한 모터 성능을 예측하기 위해 고조파 전류를 고려한 철손이 요구된다. 이를 위해 본 논문에서는 고정투자율법을 이용한 고조파 전류 입력 철손 해석 방법을 제안한다. 모터-인버터 coupling 모델을 통해 모터에 입력되는 고조파 전류를 예측하고, 해석 시에 반영하기 위한 고조파 차수 및 주파수를 결정한다. Steinmetz 식을 통해 결정된 주파수까지 철손 데이터를 fitting하여 해석에 반영하고, 고조파 차수를 고려하여 수식적인 방법을 통해 공극 mesh 개수 및 해석 step을 결정한다. 2D 유한요소해석을 통해 고조파 성분을 반영하기 위해서는 많은 수의 해석 step이 요구되지만, 이는 해석 시간이 고조파 차수에 비례하여 증가한다는 단점이 있다. 이를 해결하기 위해 기본파 전류에 대해 비선형 해석을 진행하여 투자율을 저장하고, step별 투자율 보간 방법을 적용하여 선형 해석을 통해 고조파 전류 반영 철손을 계산한다. 제안한 방법을 통해 계산한 철손은 정현파 전류 인가하여 계산한 철손 및 동일 전류 파형을 인가하여 3D 유한요소해석을 통해 계산한 철손과의 비교를 통한 검증을 진행하였다. 따라서, 제안한 방법을 통해 예측한 고조파 전류를 통해 해석 모델링 및 해석 조건을 결정한다. 추가적으로, 2D 유한요소해석 시에 투자율 보간 방법을 통해 높은 신뢰성을 갖는 철손을 빠르게 계산하여 정확한 전기 모터 성능 예측에 반영할 수 있다. 〈그림 본문참조〉
고정자 형상 변화를 통한 EV용 구동모터의 유기전압 고조파 저감 설계
위성혁(Sung-Hyeok Wi),진준우(Jun-Woo Chin),차경수(Kyoung-Soo Cha),박현진(Hyeon-Jin Park),홍정표(Jung-Pyo Hong) 한국자동차공학회 2019 한국자동차공학회 부문종합 학술대회 Vol.2019 No.5
This paper proposes the method of reducing induced voltage harmonics in high speed region through the stator optimal design of the electric vehicle traction moto. The design variables of the stator that are sensitive to lowering the induced voltage harmonics are selected using the analysis of variance(ANOVA). From the selected design variables, optimal design was carried out using the response surface method(RSM). Through the optimal design, the harmonic of the induced voltage is reduced so that the line to line induced voltage does not exceed the DC link voltage.
DCT용 자속집중형 동기전동기의 회전자 형상 등가화를 통한 열 해석
손동균(Dong-Kyun Son),진준우(Jun-Woo Chin),홍정표(Jung-Pyo Hong) 한국자동차공학회 2017 한국자동차공학회 부문종합 학술대회 Vol.2017 No.5
This paper presents a thermal model of Concentrated Flux-type Synchronous Motor(CFSM) for Dual Clutch Transmission(DCT) applying the equivalent rotor model. In order to perform the thermal analysis of CFSM using Lumped Parameter Thermal Network(LPTN), the shape of motor is reflected as hollow cylinder. Especially for the rotor of CFSM, the area, outer and inner diameter of the permanent magnet were constantly equalized. Conduction and convection thermal resistances were calculated by using dimensions of the equivalent rotor model. Then, the losses such as copper loss, iron loss, and mechanical loss are calculated and applied to the LPTN as heat sources. The heat capacity, which enables the transient thermal analysis, is calculated by using dimensions and the material properties. Finally, the temperature characteristics of each part of the CFSM are predicted using LPTN.
EV 연비 향상을 위한 구동용 IPMSM의 주운전점 효율을 고려한 최적 설계
우석원(Seok-Won Woo),차경수(Kyoung-Soo Cha),진준우(Jun-Woo Chin),임명섭(Myung-Seop Lim) 한국자동차공학회 2021 한국자동차공학회 부문종합 학술대회 Vol.2021 No.6
Recently, electric vehicles (EVs) receive considerable attention as one of the eco-friendly vehicles because of the regulations of environmental pollution. Among various studies related to EVs, studies about improving fuel economy of EVs have been actively performed. In this paper, since the interior permanent magnet synchronous motors (IPMSMs) are widely used for EV traction, the optimum design considering efficiency at main operating points of IPMSM for traction was conducted to improve the fuel economy of EV. To determine the main operating points, EV simulation was performed using Powertrain Blockset in Matlab/Simulink. Then, by using desirability function, the optimum design considering efficiency at main operating points of traction motor was carried out, considering the constraint conditions. Finally, it was confirmed that efficiency and fuel economy of the optimum model was improved compared with those of the initial model.