• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.12
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• pp.2230-2235
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• 2011

The purpose of this paper is to provide the unbalanced magnetic force and vibration mode comparison between two large interior permanent magnet machines(IPM) with different pole-slot combination considering stator and rotor eccentricity. Due to the punching tolerance, the mixed eccentricity of air-gap is inevitable. It will generate the asymmetric magnetic flux density in air-gap, which makes the unbalanced magnetic pull and vibration. The study is focused on the unbalanced magnetic force and their harmonic components according to eccentricity conditions such as static, dynamic and mixed. When the high vibration is produced especially resonance, the obtained results provide clues what eccentricity condition occurs in the machine.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.165-170
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• 2010

Recently, Interior Permanent Magnet Machine(IPM) is widely used for traction motor in the high speed train. Higher efficiency and power density are the superb performance of IPM. Due to the high power density, however, it has lots of heat source which are originated from copper losses and core losses. These heat source can cause the permanent demagnetization in magnet and the loss of torque and power. To prevent the undesirable loss in the traction motor, the accurate loss calculation and the thermal analysis should be preceded. Especially, the end-winding area and permanent magnet area should be examined correctly. In this paper, the electromagnetic fields were examined by finite element method to analyze the electromagnetic properties of IPM and thermal analysis are carried out with pre-calculated losses. To validate the analysis result, the experiment set with forced air cooling system is manufactured.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1087-1088
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• 2011

영구자석형 전동기는 높은 출력밀도를 가지므로 현재까지 많은 연구가 진행되어 왔다. 일반적으로 매입형 영구자석 동기전동기는 영구자석의 사용량이 많을수록 돌극비를 향상 시킬 수 있으므로 발생토크 성분 중 릴럭턴스 토크의 비중을 키울 수 있다. 이는 토크 발생 시 입력전류를 저감시켜 동손이 감소하고 효율을 증가시키는 효과를 기대할 수 있다. 본 논문에서는 매입형 영구자석 동기전동기의 등가자기회로법를 이용한 설계에 대해 다루고자 한다. 등가자기회로법은 계산시간이 빠르고 전동기 구성인자들의 영향을 신속하게 살펴 볼 수 있으므로 초기설계에 많이 사용된다. 본 논문에서는 등가자기회로법을 이용하여 공극자속밀도를 산정한 후 슬롯을 고려한 relative permeance, 그리고 무부하 역기전력을 산정하고 최종적으로 유한요소법을 이용하여 검증한다.

• Journal of Electrical Engineering and Technology
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• v.12 no.5
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• pp.1980-1990
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• 2017

A study on the multi-objective optimization of Interior Permanent-Magnet Synchronous Motors (IPMSMs) with 2, 3, 4 and 5 flux barriers per magnetic pole, based on Genetic Algorithm (GA) is presented by considering the aspect of irreversible demagnetization. Applying the 2004 Toyota Prius single-layer IPMSM as the reference machine, the asymmetrical two-, three-, four- and five-layer rotor models with the same amount of Permanent-Magnets (PMs) is presented to improve the torque characteristics, i.e., reducing the torque pulsation and increasing the average torque. A reduction of the torque pulsations is achieved by adopting different and asymmetrical flux barrier geometries in each magnetic pole of the rotor topology. The demagnetization performance in the PMs is considered as well as the motor performance; and analyzed by using finite element method (FEM) for verification of the optimal solutions.

• Proceedings of the KIEE Conference
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• 2005.07d
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• pp.2561-2563
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• 2005

영구자석 매입형 동기전동기(IPM)의 전류제어는 표면부착형 동기전동기(SPM)보다 더 복잡하다. 그 이유는 전류에 대한 최대토크특성 때문이며 고성능 토크제어를 위해서는 d-전류와 q-전류를 독립적으로 제어를 할 수 있는 방법이 필요하다. 그러나 전류들간의 상태커플링 때문에 독립적으로 제어하기가 어려우므로 상태 디커플링이 필요하다. 상태디커플링은 인턱턴스에 의해 생기며 인턱턴스의 변화 때문에 상태디커플링이 쉽게 이루어지지 않는다. 그러므로 인턱턴스의 불확실성에 대처할 수 있는 디커플링 방법의 개발을 바탕으로한 전류들의 독립적인 제어가 필요하다. 본 논문은 슬라이딩 모드제어기법을 이용하여 디커플링할 수 있는 방법을 제안하기로 한다. 기본적인 제어방법은 PI제어이며 슬라이딩모드를 이용하여 PI제어의 성능을 향상시키는 접근방법으로도 생각할 수 있다.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2001.04a
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• pp.9-25
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• 2001

Fairchild has been developing a new class IPM called SPM consisting of dramatic Packaging technology to achieve the lowest cost rind better performance for low power home appliances and industrial AC drive applications. The first Fairchild SPM development with IGBT 600V/15A for washing machine application started in 1999 and was completed successfully. Fairchild SPMs are going to be the best solution for low power inverter-driven AC drive system after 2001. The new SPM Packages like SPM ∥ and SPIM for the next generation IPM with the highest competitiveness (cost & performance) shall be continuouslly developed.

• Journal of Electrical Engineering and Technology
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• v.9 no.4
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• pp.1277-1282
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• 2014

Concentrated flux interior permanent magnet (CFIPM) motors have the advantage that their utilization of flux linkage is more efficient than that of general IPM motors and CFIPM motors are suitable for washing machine motors, which demand low-speed, high-torque specifications. However, low efficiency occurs in the low-speed high-torque mode considering the high-speed operation for spin mode. This paper proposes a magnet overhang structure between the rotor core that reduces leakage flux and improves efficiency for a CFIPM in wash mode. Optimization of the 3D design of magnet overhang structures is performed to improve the efficiency with the same quantity of permanent magnets. The validity of the optimal design is experimentally verified through the fabrication of prototypes.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.732-733
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• 2015

본 논문에서는 외전형 영구자석 동기전동기(Outer rotor Permanent Magnet Synchronous Motor)의 회전자 형상에 따른 토크특성을 비교하였다. 표면부착형 영구자석(SPM) 형태의 FAN용 PMSM을 설계하고 이 모델을 기준으로 동일한 외경사이즈를 갖지만 더 높은 토크 밀도를 갖는 4가지 매입형 영구자석(IPM) 형태의 PMSM을 제시한다. Finite Element Analysis(FEM)을 통하여 각 모델의 특성을 해석하고 자석 사용량과 토크를 비교 및 분석하였다.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.862-863
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• 2015

This paper presents an improved estimation procedure for the contribution to no-load flux linkage created by the permanent magnet (PM) in interior permanent magnet synchronous machines. In the proposed method, the saturation effect in stator and rotor cores are taken into account by utilizing the frozen permeability method (FPM). This improved procedure can evaluate the contribution for each local element in the PM to the no-load flux linkage. According to the analysis results, an effective PM topology optimal design can be carried out to achieve high utilization ratio of PM in the machine. In order to determine the threshold of the low contribution of PM for removing, one multi-objective optimization model is proposed. Based on the optimal threshold, the final optimal topology design of PM can be achieved.

• Communications for Statistical Applications and Methods
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• v.30 no.3
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• pp.331-341
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• 2023

Handling missing values in data analysis is essential in constructing a good prediction model. The easiest way to handle missing values is to use complete case data, but this can lead to information loss within the data and invalid conclusions in data analysis. Imputation is a technique that replaces missing data with alternative values obtained from information in a dataset. Conventional imputation methods include K-nearest-neighbor imputation and multiple imputations. Recent methods include missForest, missRanger, and mixgb ,all which use machine learning algorithms. This paper compares the imputation techniques for datasets with mixed datatypes in various situations, such as data size, missing ratios, and missing mechanisms. To evaluate the performance of each method in mixed datasets, we propose a new imputation performance measure (IPM) that is a unified measurement applicable to numerical and categorical variables. We believe this metric can help find the best imputation method. Finally, we summarize the comparison results with imputation performances and computational times.