• 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.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2010년도 하계학술대회 논문집
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• pp.448-449
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• 2010

This paper proposes a sensorless control strategy for the Interior Permanent Magnet Synchronous Motor (IPMSM) by using the parallel reduced-order Extended Kalman Filter. The sensorless control strategy is composed with two EKFs alternately computed every sampling period with a new model. The new model is based on the extended electromotive force (EEMF) which has a simple structure, making position estimation possible without approximation. The proposed strategy can save computation time and estimate rotor speed and position. To verify the merit of the proposed strategy, simulation and experimental results validate the theoretical analysis and show the feasibility of the proposed control strategy.

• 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.

• Journal of Electrical Engineering and Technology
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• 제12권2호
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• pp.683-688
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• 2017

The unscented Kalman filter features a direct transforming process involving unscented transformation for removing the linearization process error that may occur in the extended Kalman filter. This paper proposes a reduced-order unscented Kalman filter for the sensorless control of a permanent magnet synchronous motor. The proposed method can reduce the computational load without degrading the accuracy compared to the conventional Kalman filters. Moreover, the proposed method can directly estimate the electrical rotor position and speed without a back-electromotive force. The proposed Kalman filter for the sensorless control of a permanent magnet synchronous motor is verified through the simulation and experimentation. The performance of the proposed method is evaluated over a wide range of operations, such as forward and reverse rotations in low and high speeds including the detuning parameters.

• 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.

• Journal of international Conference on Electrical Machines and Systems
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• 제1권1호
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• pp.84-90
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• 2012

Various methods have been proposed to identify the flux position in an interior permanent magnet synchronous motor (IPMSM) without the use of mechanical sensors. To achieve this, a method that uses both the back electromotive force (EMF) and the saliency to identify the flux position in the IPMSM without the injection of high-frequency components at low speeds has been reported. This method was then extended in order to drive the motor with no load to a light load. We propose a combination of these methods with different proportional-integral (PI) controllers for controlling $di_{dest}$/dt and $di_{qest}$/dt. We also introduce compensation values $F_L$ and $F_H$ to reduce the position error when the estimation rule is being selected.

• 대한화학회지
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• 제17권4호
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• pp.229-234
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• 1973

非水溶液 에틸렌디아민中에서, K-Hg,KI($C_1$) II ($C_2$)KI, Hg-K의 農談電位를 構成하여, 電位差法으로 電位差를 測定하여, Debye-Huckel型의 活性係數式으로 計算한 理論値와 比較한 결과 Marshall-Grunwald 식이 잘 適用되었다.

• 전력전자학회논문지
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• 제24권2호
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• pp.127-133
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• 2019

This paper proposes a restarting method for extended electromotive force (EEMF)-based sensorless permanent magnet synchronous motor (PMSM) drive systems. The sensorless PMSM drive systems generally estimate the rotor speed and angle based on EEMF. However, if the inverter is stopped while the PMSM is rotating, the initial rotor speed and angle are required for restart. Therefore, the proposed restarting method estimates the initial rotor speed and angle using the short-circuit current generated by applying zero voltage vector from the inverter. The validity of the proposed method is verified by simulation and experimental results.

• 한국컴퓨터산업학회논문지
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• 제6권5호
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• pp.741-748
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• 2005

형광램프용 전자식 안정기의 효율개선 및 램프의 수명연장을 위하여 강유전체 커패시터와 시간지연스위칭회로로 구성된 절전모듈을 개발하고 적용하였다. 절전모듈에 사용된 강유전체 세라믹스를 이용하여 형광램프의 부저항특성과 최적화를 시키고, 시간지연회로를 통하여 점등초기 예열형에서 비예열형으로 스위칭시켜 점등 중 필라멘트에서 소비되는 전력을 제거함으로써 약 2W의 소비전력을 감소시켜 효율개선을 실현하였으며, 역기전력 제거기능을 통하여 점등 초기 형광램프 필라멘트에 가해지는 충격을 최소화함으로써 형광램프의 수명을 연장시켰다.