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[논문 or 기술논문 택일] 대용량 직접구동형 발전기의 기계적 거동 특성에 관한 연구
노윤철(Yun Cheol Ro),안대균(Dae Gyun Ahn),한승호(Seung Ho Han) 대한기계학회 2013 대한기계학회 춘추학술대회 Vol.2013 No.5
AFPM(Axial Flux Permanent Magnet)-typed machine for a large-scaled direct-drive generator of offshore wind turbines has been attractive due to its higher torque effect per unit volume and higher power density in comparison with other such as the RFPM(Radial Flux Permanent Magnet)-typed machine. When this machine will be applied to an offshore wind turbine, the stiffness and robustness of the supported structures should be investigated carefully due to its high electro-magnetic forces which cause a significant deformation of main members. This deformation raises an unexpected change of air-gap clearance which can disturb seriously the power production. The light weight design is also at issue for a higher efficiency of the power production. In this study, a topology model of the direct-drive generator for 2.5MW wind turbine using the AFPM-typed machine was proposed, and evaluation of mechanical behaviors was carried out by electro-magnetic mechanical coupling analysis. Results showed that the weigh of the proposed model could be reduced by 20% in comparison with the conventional generator at condition satisfying the requirements of the structural behaviors.
신경망모델 기반 다목적 유전자 알고리즘을 적용한 대용량 직접 구동형 풍력발전기 형상 최적화
노윤철(Yun Cheol Ro),안대균(Dae Gyun Ahn),이광기(Kwang Ki Lee),한승호(Seung Ho Han) 대한기계학회 2013 대한기계학회 춘추학술대회 Vol.2013 No.12
Among the direct-drive generator, the AFPM(Axial Flux Permanent Magnet)-typed machine has been attractive due to its higher torque effect per unit volume and higher power density in comparison with others such as the RFPM(Radial Flux Permanent Magnet)-typed machine. Since the AFPM-typed machine has been used mainly to smallscaled generator, the characteristics of structural behaviors such as stiffness and robustness should be investigated carefully when this machine will be applied to a generator for large-scaled wind turbine. In this study, optimization of the direct-drive generator for 2.5MW wind turbine using the AFPM-typed machine was proposed by using neural network model based MOGA(Multi-Objective Genetic Algorithm). An electro-magnetic and structural interaction analysis was carried out to find optimal design variables which meet the requirements of the structural stiffness such as limitation of air-gap clearance and global mechanical behavior by neural network model generated from orthogonal array. The structural weight and stress of the proposed model compared to initial generator could be reduced by 13.3% and 13.78% in a condition satisfying the constraint requirement of deformation.
May-Thurner 증후군의 임상 양상과 급성 폐동맥 색전증과의 연관성
노윤채,이재백,진영호,정태오,조시온,김소은,이정문,윤재철 대한응급의학회 2020 대한응급의학회지 Vol.31 No.3
Objective: May-Thurner syndrome (MTS) is a condition, in which the left common iliac vein is compressed by the right common iliac artery and spine, resulting in an increased risk of deep vein thrombosis (DVT). This study examined the clinical features of MTS and relationship of MTS with a pulmonary embolism (PE) in acute DVT patients. Methods: This study was a retrospective observational study using the electronic medical records of patients with acute DVT in 2018. Acute DVT patients were divided into the MTS group (n=18, 23.1%) and non-MTS group (n=60, 76.9%) according to the presence of MTS. The following items were compared: demographic data, risk factors of DVT, vital signs, laboratory results, involvement site of vein, incidence of PE, and severity of PE. Results: The presence of risk factors was similar in the two groups. All MTS patients had DVT in the left lower extremity. The ilio-femoral DVT (21.7% vs. 77.8%, P<0.001) and mixed DVT (both ilio-femoral and femoro-popliteal, 10.0% vs. 44.4%; P=0.002) were observed more frequently in the MTS group. The incidence of PE was higher in the non-MTS group (65.0%) than in the MTS group (33.3%) (P=0.017). On the other hand, the severity of PE assessed with main pulmonary artery involvement or hemodynamic instability, and right ventricular dysfunction did not show a significant difference between the two groups. Conclusion: DVT could develop with the presence of risk factors in MTS patients. DVT patients with MTS might reduce the risk of developing PE compared to those without MTS, but the severity of PE was similar in the two groups.
Tolerance Optimization of a Lower Arm by using Genetic Algorithm and Process Capability Index
이광기,한승호,노윤철 한국정밀공학회 2014 International Journal of Precision Engineering and Vol. No.
Tolerance optimization that considers variances of design variables should be performed before beginning the manufacturing processfrom a cost-effective perspective in the design process. The authors used a genetic algorithm and the process capability index (Cpk)to solve the robust objectives and probability constraints and to formulate a constrained optimization problem into an unconstrainedone. The design space provided by the Cpk-values of weight and stress on the lower arm of a vehicle’s suspension was explored byusing the central composite design method and the 2nd order Taylor series expansion. The optimal solutions were found via the geneticalgorithm, in which the Cpk-values took into account the variances occurring in a design variable's tolerances. The mean andstandard deviation of Mass and Smax were predicted by using the 2nd order Taylor series expansion and the 2nd order polynomialresponse surface models generated from the central composite design method. The Cpk of Mass and Smax were calculated, wherethe Pareto set was generated by maximizing the Cpk-values via the MOGA (Multi-Objective Genetic Algorithm). From the Paretoset, optimal alternatives were selected and verified by simulated results from FE (Finite Element) analysis and Monte-Carlosimulation.
Light Weight Design of Direct-Drive Generator for Large- Scale Wind Turbine
최다운,한승호,노윤철,김양균,조윤현 한국정밀공학회 2014 International Journal of Precision Engineering and Vol. No.
A direct-drive generator for large-scale wind turbine provides higher energy density in comparison with a gear train type generator. An AFPM (Axial Flux Permanent Magnet)-type machine has been the most attractive for the direct-drive generator due to its highertorque effect per unit volume and higher power density. The electronic machine system with a very large diameter, however, has tobe used due to operation at low rotational speed of main shaft. Supported structures for the electronic machine system occupy at least80% of total weight of the direct-drive generator. The light weight design, therefore, is at issue in the industries manufacturing theAFPM-type generator for large-scaled wind turbines. In this study, a topology model of the direct-drive generator for 2.5MW windturbine using the AFPM-type machine was proposed, which has hollow shapes of the rotor with annular disc, the stator and the mainshaft mounted on coupled slew bearings. Analytic results obtained from an electro-magnetic and structural interaction analysisshowed that the structural weight of the proposed model compared to conventional generator can be reduced by 30% in a conditionsatisfying the requirements of the structural behaviors.