• 한국산업융합학회 논문집
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• 제2권2호
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• pp.91-102
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• 1999

The paper describes a robust adaptive control algorithm for induction motor drive without speed sensor at low speed range. The control algorithm use only current sensors in a space vector pulse width modulation within loop control with rotor speed estimation and voltage source inverter. On-line rotor speed estimation is based on utilizing parallel model reference adaptive control system. MRAC of the modified flux model for flux and rotor speed estimator uses dual-adaptation mechanism, ${\omega}_r$ and ${\omega}_e$ scheme. The estimated flux components in the model can be compensated from the effects of offset errors on pure integrals. It can be compensated to the parameter variations and torque fluctuation with speed estimation in less then 10 rad/sec. In a simulation, the proposed induction motor control algorithm without speed sensor at very low speed range are shown to operate very well in spite of variable rotor time constant and fluctuating load without change the controller parameters. The suggested control strategy and estimation method have been validated by simulation study, and it proposed the designed system for the implementation using TI320C31 DSP/ASIC controller.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 B
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• pp.1085-1087
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• 2004

The space harmonic analysis, as an analytical method, is used to estimate the flux distribution in the air gap of the brushless motors in this paper. With the flux distribution, back-emf and torque characteristics can be estimated.[1-7] Therefore, the air gap flux distribution of surface type permanent magnet motor according to the motor specifications are studied to estimate the torque characteristics in this paper. To validate the analysis result of this method, 2-dimensional finite element analysis is performed and the air gap flux density is compared to that from space harmonic analysis.

• 대한기계학회논문집
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• 제14권6호
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• pp.1679-1688
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• 1990

본 연구에서는 역산법으로 열확산계수를 추정하기 위하여 비선형 매개변수 추 정법을 사용하며, 실험데이터의 통계적 처리방법, 추정이론을 정리하여 이 추정법에 적합한 알고리즘을 만들었다. 수정된 Gauss법을 컴퓨터에 사용할 수 있도록 프로그 램을 개발하였으며, 이 방법의 정확성을 증명하기 위하여 일정열유법과 동일한 실험장 치를 사용하되 경계조건이나 초기조건을 시간의 변화에 따라 이산적으로 측정하여, 매 개변수인 열확산계수를 온도의 함수로 찾고자 하였으며, 통계적인 개념보다는 역산적 인 면에 더 치중하였다.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제11B권2호
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• pp.51-58
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• 2001

This paper proposes a new strategy to estimate the rotor flux of an induction machine for the direct field oriented control. Electrical model of the induction machine presents the basic idea based on observer structure, which is composed of voltage model and current model. But the former has the defects in low speed range, the latter has the defects of sensitivity to machine parameters. In spite of these shortcomings, the closed loop flux observer based on two models has been prevalent estimation method for the direct field oriented control. In this paper, generalized analysis method named "observer characteristic function method"is proposed to analyze the kinds of the linear flux observers in unified form. With the observer characteristic function, the estimated rotor flux error involved in the classical methods can be easily clarified. Moreover, the novel rotor flux observer based on this analysis is also presented and the effectiveness of the observer has been verified by the simulation and experimental results.

• 전력전자학회논문지
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• 제12권1호
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• pp.65-73
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• 2007

본 논문은 1-Hz의 낮은 고정자 전류 주파수에서도 동작하는 순수적분 기반의 자속추정을 위한 온라인 전류측정 오차 보상방법을 제안한다. 오프셋 전류와 변환이득오차에 의한 역상분 전류 성분은 상태관측기를 이용하여 제거하고, 동시에 변환이득오차에 의한 역상분 전류는 동기좌표계에서 영구자석에 의하여 발생된 q축 자속을 기준모델에 의한 값과 추정된 자속에 의한 값 사이의 차이에 의하여 보상한다. 이 보상기는 PI제어기를 이용하여 두 값 사이의 오차가 0이 되도록 제어한다. 또한 적분기 초기값 오차 및 관측기의 전동기 상수 오차에 의한 잔여오차 보상방법도 제안하였다. 타당성을 입증하기 위하여 1.1-kW 영구자석형 동기전동기(PMSM)에 제안된 보상 방법을 구현하여 다양한 실험을 수행하였다.

• 전력전자학회논문지
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• 제26권5호
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• pp.364-371
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• 2021

A magnetic flux saturation model of Synchronous Reluctance Motors (SynRMs) and a parameter estimation method are proposed at standstill. The proposed magnetic flux model includes the nonlinear relationship between the current and the magnetic flux for self-saturation and cross-saturation. Voltage is injected at standstill to estimate the magnetic flux saturation model. Voltages are injected into the d-axis and q-axis to obtain data on self-saturation. Subsequently, voltages are simultaneously injected into the d-q axis to obtain data on cross-saturation. On the basis of the measured current and the calculated magnetic flux, the parameters of the proposed model are estimated using the least square method (LSM). Simulation and experiment were performed on a 1.5-kW SynRM to verify the proposed method. The proposed model can be used to create a high-efficiency operation table, a sensorless algorithm, and a current controller to improve the control performance of a motor.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 B
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• pp.794-796
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• 2004

In the evaluation of performance for the algorithm of sensorless speed control, the ability of speed control in low speed range and starting is important points. First of all, stability of low speed control is highly required in the application which needs high performance in speed control. For this requirement, this paper represents simple method to estimate the rotor position by comparing reference linkage flux with it's estimation. In the estimation of linkage flux, this paper uses voltage-current model for increasing the performance of speed control in low speed range.

• Journal of Electrical Engineering and Technology
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• 제10권1호
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• pp.251-260
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• 2015

The main purpose of this paper is to describe a DTC (direct torque control) method for four-switch brushless dc motor (BLDCM) drive. In the method, a novel voltage space vector modulation scheme, an optimal switching table, and a flux observation method are proposed. Eight voltage vectors are summarized, which are selected to control BLDCM in SVPWM pattern, and an optimal switching table is proposed to improve the torque distortion caused by midpoint current of the split capacitors. Unlike conventional flux observers, this observer does not require speed adaptation and is not susceptible to speed estimation errors, especially, at low speed. Global asymptotic stability of the flux observer is guaranteed by the Lyapunov stability analysis. DC-offset effects are mitigated by introducing a PI component in the observer gains. This method alleviates the undesired current and torque distortion which is caused by uncontrollable phase. The correctness and feasibility of the method are proved by simulation and experimental results.

• 전기학회논문지
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• 제56권7호
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• pp.1241-1249
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• 2007

Lately, many approaches of speed sensorless control method for Interior Permanent Magnet Synchronous Motor(IPMSM) ha, been developed. This paper proposes a novel sensorless algorithm for speed estimation of IPMSM. First of all, proposes sensorless method estimates flux of rotor using foundational voltage equation of IPMSM and then estimates position and speed of rotor using Phase Locked Loop(PLL). Proposed sensorless algorithm demonstrated through simulation using Matlab simulink and experiment.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제50권8호
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• pp.374-383
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• 2001

This paper presents the torque estimation scheme by Energy Conversion Method (ECM) that can be applied to the torque control of switched reluctance motor. There are two types of torque estimation method by ECM. One is the method using mechanical output energy and another is that using co-energy. When the torque is estimated by ECM, the estimated flux linkage can be obtained by voltage equation and Luenberger observer. By comparing the torque estimated by ECM with that be FEM, we verify the feasibility of the proposed torque estimation by ECM.