• 전력전자학회:학술대회논문집
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• 전력전자학회 2010년도 추계학술대회
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• pp.314-315
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• 2010

This paper results from the application of IPM for hybrid vehicles using Matsui method and Extended EMF mothed. These 2 methods are typical methods based on EMF, which is usually used in position sensorless control. When d-axle current was 0, both Matsui method and Extended EMF method showed desirable results. On the other hand, when d-axle current was not 0, only Extended EMF appeared satisfactory. This means that Matsui method is more vulnerable to parameter variation. Thus, Extended EMF method would be better than Matsui method to be used in field weaking or MTPA control.

• 조명전기설비학회논문지
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• 제25권1호
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• pp.78-84
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• 2011

Using sensors to detect current or voltage of motors is disadvantaged because motor is exposed to vibration, impacts, corrosion, high temperature and humidity in the machinery structure like HEV. In the case of IPMSM, position information is included not only in the flux or EMF term but also in the rotator inductance because of its saliency. To solve this problem, a new mathematical model of IPMSMs on fixed frame is proposed and an extended EMF includiing rotating position information is defined to estimate extended EMF. A strong low-pass filter through the variable cut-off frequency using velocity function was proposed. This makes it is possible to estimate extended EMF by least order disturbance observer. The proposed method was proved through the experiment.

• Journal of Power Electronics
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• 제12권4호
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• pp.604-614
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• 2012

This paper presents a comparative study of position sensorless control schemes based on back-electromotive force (back-EMF) estimation in permanent magnet synchronous motors (PMSM). The characteristics of the estimated back-EMF signals are analyzed using various mathematical models of a PMSM. The transfer functions of the estimators, based on the extended EMF model in the rotor reference frame, are derived to show their similarity. They are then used for the analysis of the effects of both the motor parameter variations and the voltage errors due to inverter nonlinearity on the accuracy of the back-EMF estimation. The differences between a phase-locked-loop (PLL) type estimator and a Luenberger observer type estimator, generally used for extracting rotor speed and position information from estimated back-EMF signals, are also examined. An experimental study with a 250-W interior-permanent-magnet machine has been performed to validate the analyses.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2001년도 종합학술발표회 논문집 Vol.11 No.1
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• pp.315-318
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• 2001

We are proposing a new mobile phone antenna, which has a specially manufactured Mn-Zn cylindrical ferrite bead inside of the helical coil of the antenna. The extended antenna radiation patters and the spatial peak SAR averaged over 1 gram simulated tissue with and without the ferrite bead insertion were measured at 824 MHz. The results show that the ferrite bead resulted in SAR reduction about 20 %, and reflection coefficient increase about 7 % for the extended antenna. The applicability of this scheme to the antenna mass production is quite feasible.

• 전기학회논문지P
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• 제65권4호
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• pp.273-279
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• 2016

In this paper, a high-performance control of the induction motor for electric car was implemented to escape dependence of the rare earth magnet. Proposed high-efficiency control algorithm is a Direct Rotor Field-Oriented Control method that is insensitive to the fluctuation of motor parameters. In the DRFOC method, we need to compensate fluctuation of stator transient inductance and magnetizing inductance caused by the magnetic saturation of induction motor in high-speed area. This paper proposes Back-EMF Observer based on stator current estimator of Luenberger style. Motor control system applied the Voltage Feedback Flux Weakening Control method for high-speed operation. The proposed algorithm was verified through tests by the power train of Extended Range Electric Vehicle consists of induction motor and differential gear.

• 전력전자학회논문지
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• 제21권5호
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• pp.449-452
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• 2016

This paper presents a simplified analysis on the rotor position detection error in sensorless interior permanent magnet brushless DC motor (BLDCM) drives, wherein terminal voltage sensing based on the back-electromotive force (back-EMF) zero-crossing point detecting circuitry is employed. The effect of a rotor saliency on the back-EMF's zero-crossing point detection is analyzed using the extended EMF-based voltage equation of the interior permanent BLDCM in a stationary reference frame, and thus the overall analysis is considerably simplified compared to the conventional one. Simulation results are provided to verify the effectiveness of the proposed method.

• 대한전자공학회논문지
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• 제6권3호
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• pp.12-23
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• 1969

본논문에서는 길이에 비해서 그 반지름을 무시할 수 있는 선형다피장 안테나에서 그 중앙점에 관하여 대칭인 3쌍의 급전점을 취하고 각쌍마다에 동일한 주전력을 급전하는 6점급전안테나계의 전류분포를 Hallen의 수차근사법에 따라서 이론적으로 해석하였으며, 이 결과 얻어진 전류분포식은 1차근사식으로서 일반적으로 6점급전안테나상 각부의 전류분포를 가늠하는데 사용될 수 있을 것임을 예시하였다.

• 전력전자학회논문지
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• 제16권3호
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• pp.266-273
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• 2011

본 논문에서는 매입형 영구자석 동기 전동기(IPMSM)의 확장형 역기전력(EEMF) 모델을 이용한 저감차수 병렬형 확장형 칼만 필터(EKF)를 이용한 센서리스 제어 기법을 제안한다. 제안된 센서리스 제어 기법은 간단한 수학적 구조로 매입형 영구자석 동기전동기 구동에 적합한 확장형 역기전력 모델을 이용하여 두 개의 저감 차수 형태로 표현하였다. 이러한 두 모델은 매 샘플링 시간마다 확장형 칼만 필터에 번갈아 연산된다. 행렬의 차수를 저감하여 EKF의 연산시간의 단축과 알고리즘 구현의 부담을 줄였으며 센서리스 제어의 안정적인 상태 벡터의 추정을 위해 병렬로 구동하는 두 모델에 의해 추정된 정보를 이용하였다. 제안된 기법은 실험 결과를 통하여 안정적인 위치 추정 및 속도 추정 성능을 검증 하였으며, 전 차수 EKF와의 연산 시간 비교를 통하여 우수성을 검증하였다.

• Journal of Electrical Engineering and Technology
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• 제12권2호
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• pp.711-717
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• 2017

This paper proposes an improved sensorless control to estimate the rotor position of an interior permanent magnet synchronous motor. A phase-locked loop (PLL) is used to obtain the phase angle of the grid. The rotor position can be estimated using a PLL based on extended electromotive force (EEMF) because the EEMF contains information about the rotor position. The proposed method can reduce the burden of calculation. Therefore, the control period is decreased. The simulation and experimental results confirm the effectiveness and performance of the proposed method.

• Journal of Electrical Engineering and Technology
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• 제12권3호
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• pp.1166-1176
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• 2017

Estimation errors of the rotor speed and position in sensorless control systems of Permanent Magnet Synchronous Motors (PMSM) will lead to low efficiency and dynamic-performance degradation. In this paper, a parallel-type extended nonlinear observer incorporating the nominal parameters is constructed in the stator-fixed reference frame, with rotor position, speed, and the load torque simultaneously estimated. The stability of the extended nonlinear observer is analyzed using the indirect Lyapunov's method, and observer gains are selected according to the transfer functions of the speed and position estimators. Taking into account the parameter inaccuracies issue, explicit estimation error equations are derived based on the error dynamics of the closed-loop sensorless control system. An equivalent flux error is defined to represent the back Electromotive Force (EMF) error caused by the inaccurate motor parameters, and a compensation strategy is designed to suppress the estimation errors. The effectiveness of the proposed method has been validated through simulation and experimental results.