• Journal of Advanced Marine Engineering and Technology
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• 제21권5호
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• pp.503-511
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• 1997

In 3 phase induction motor control system, the speed control using the load torque observer becomes robust against disturbances by means of a feed-forward control of the estimated load torque component. In case of variation of inertia moment, the estimated load torque has error because the observer uses the nominal inertia to estimate the load torque. And so, it is difficult to obtain good speed control characteristics. This paper has two study target strategy. First, we executes feed-forward control with the load torque observer when motor inertia has nominal value and compare it with conventional PI con¬trol. The second strategy estimates inertia moment error using the load torque observer when inertia moment change. The proposed two strategy is confirmed through the computer simulations and the experimental implementations by TMS320C31 microprocessor.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년 학술대회 논문집 정보 및 제어부문
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• pp.133-135
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• 2006

This paper considers a speed control problem of DC motor under load variations. In order to reduce the effect of load variation, a disturbance observer has been designed for the given system. With a cheap encoder there exists considerable measurement noise in the velocity feedback and it should be reflected in designing the disturbance observer. The authors have obtained the nominal transfer function of a DC motor and designed a disturbance observer for the control purpose. With the disturbance observer a digital controller has been implemented using a DSP(TMS320F2812). Some experiments show the enhanced performance of the control system with the proposed method.

• 한국안전학회지
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• 제13권1호
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• pp.54-63
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• 1998

This paper proposes a theoretical analysis of a closed loop adaptive speed control system for control the inverter driven permanent magnet synchronous motor(PMSM). This control system utilizes a mechanically sensorless state observer for the generation of all controller feedback information. The observer processes measurements of stator frame voltage and current to produce estimates of rotor position and speed and rotor frame currents. It is shown that the identity observer, when properly formulated, has the same linearized error dynamics as the extended kalman filter(EKF). Consequently, it is shown that the gains within the identity observer can be designed in a manner identical to that of the EKF. In this way, the designability of the nonlinear observer is assured, as is the optimality of its performance for small errors. A sequence of simulation are performed and they demonstrate the successful performance.

• 전기학회논문지
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• 제66권12호
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• pp.1732-1739
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• 2017

This paper presents a sensorless vector control algorithm of closed loop Gopinath flux observer to enhance the robustness at low speed by switching P/PI mode. Closed loop Gopinath flux observer has the problem in sensorless vector control of induction motor at low speed. This paper solves the problem using the characteristic function of closed loop Gopinath flux observer. P mode shows better performance than PI mode under the cut-off frequency of observer. But P mode always has a flux error due to DC offset, so this paper combines P mode and PI mode. This algorithm shows good performance over wide speed range. The performance has been confirmed through computer simulations using MATLAB SIMULINK and experiments.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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• pp.125-130
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• 1998

This paper presents a speed control for ultrasonic motors using a PI controller and disturbance torque observer. Since the PI gains and the observer's poles are generally fixed, the control performance deteriorates when the driving conditions vary much. Therefore, we propose the speed control scheme that the PI gains and the observer's poles are adjusted on-line in accordance with the speed ripple using fuzzy reasoning.

• Journal of Advanced Marine Engineering and Technology
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• 제28권4호
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• pp.641-647
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• 2004

By most sensorless speed control schemes for induction motor. the control performances in high speed range are good, but it is difficult to obtain satisfactory results in low speed region. This paper proposes a new method controlling the low and the high speed regions separately to attain the stable operation in the overall range. The current error compensation method, in which the controlled stator voltage is applied to the induction motor so that the error between stator currents of the numerical model and the actual motor can be forced to decay to zero as time proceeds. is used in the low speed region In the high speed region. the method with adaptive observer is utilized. This control strategy contains an adaptive state observer for flux estimation. The rotor speed can be calculated from the rotor flux and the motor currents. The experimental results indicate good speed and load responses from the very low speed range to the high, and also show accurate speed changing performance between the low and the high speed range.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.161-164
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• 2001

This paper presents a digital speed sensorless control system for Reluctance Synchronous Motor (RSM) drives with direct torque control (DTC). The system consist of stator flux observer, rotor speed estimator, torque estimator two hysteresis band controllers, an optimal switching look-up table. IGBT voltage source inverter, and TMS320C31DSP controller by using fully integrated control software. The stator flux observer is based on the combined voltage and current model with stator flux feedback adaptive control that inputs are current and voltage sensing of motor terminal with estimated rotor angle for wide speed range. The rotor speed is estimated by the observed stator flux-linkage space vector. The estimated rotor speed can be determinated by differentiation of the rotor position used only in the current model part of the flux observer for a low speed operating area. In order to prove the suggested speed sensorless control algorithm. There are some simulation and testing at actual experimental system. The developed digitally high- performance speed sensorless control system are shown a good speed control response characteristic results and high Performance features using 1.0Kw RSM.

• 대한전기학회논문지:시스템및제어부문D
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• 제54권10호
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• pp.587-594
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• 2005

An adaptive observer for rotor resistance is designed to estimate rotor flux for the a-b model of an induction motor assuming that rotor speed and stator currents are measurable. A singularly perturbed model of the motor is used to design an Adaptive sliding mode observer which drives the estimated stator currents to their true values in the fast time scale. The adaptive observer on the sliding surface is based on the equivalent switching vector and both the estimated fluxes and the estimated rotor resistance converge to their true values. A speed controller considering the effects of parameter variations and external disturbance is proposed in this paper. First, induction motor dynamic model at nominal case is estimated. based on the estimated model, speed controller is designed to match the prescribed speed tracking specifications. Then a dead-time compensator and a robust controller are designed to reduce the effects of parameter variations and external disturbances. the desired speed tracking control performance can be preserved under wide operating range, and good speed load regulating performance. Some simulated results are provided to demonstrate the effectiveness of the Proposed controller.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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• pp.774-779
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• 1998

For the speed control of motors, the position or speed sensors are necessary to obtain the position information of the rotor. Specially, SRM(Switched Reluctance Motor) needs an accurate rotor position data because both the rotor and the stator have a salient pole structure. High functional sensors like resolver or encoder are expensive and have complex connecting lines to the controller so the pure signals are apt to be mixed with noised. In the sight of SRM drives, the high temperature, heavy dust, and the EMI surroundings reduce the reliability of speed and position sensors. Therefore, the speed and position sensorless control algorithms using observer have been accepted widely. In this paper An adaptive sliding observer is described to control the SRM without speed or position sensors. The adaptive sliding observer is set on the basis of variable structure control theory. The sliding surface is constructed by current error terms and this surface guarantees the errors converge to "zero". The stability of observer is affirmed by Lyapunov stability analysis and popov's hyper stability theory.ty theory.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2002년도 추계종합학술대회
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• pp.808-811
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• 2002

유도전동기 센서리스 벡터제어의 안정성에 대하여 많은 연구가 되어지고 있다. 그 결과 유도전동기의 고정자 저항, 회전자 저항, 시스템 파라미터의 변화에 대하여 센서리스 방법이 속도 센서가 있는 경우와 비교하여 불안정하게 되기 쉽다는 것이 분명하다. 본 논문에서 속도 지령 $\omega$$_{r}$일 스텝 변화에 대하여 관성 모멘트 J 를 변화하는 경우, 유도전동기 회전자 저항 R$_{r}$,을 변화하는 경우에 대해 살펴보고, 전동기의 파라미터, 시스템 파라미터의 변화에 영향을 받지 않는 제어 방법으로 전동기 전압, 전류, 전동기 정수에 의한 속도 Observer를 구성하여 속도 추정을 행하는 방법에 대하여 제안하고 타당성을 입증하고자 한다.