• 전력전자학회논문지
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• 제11권6호
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• pp.551-557
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• 2006

교류 전동기는 전류의 측정오차와 데드타임(dead time) 등의 영향으로 전기각주파수에 동기된 주기적인 토크리플이 발생한다. 본 논문에서는 주기적인 토크리플 보상알고리즘을 제안한다. 보상기는 토크리플에 의해 생성된 속도리플의 크기을 관측하는 속도리플 관측기와 관측한 양으로 토크리플을 보상하는 토크리플 보상기로 나누어진다. 본 논문에서는 토크리플 보상기의 해석을 통해 정상상태에서 속도리플이 제거되고 새롭게 제안된 속도리플 관측기을 적용하여 성능이 향상됨을 보였다. 제안한 주기적인 토크리플 보상알고리즘에 의해 토크리플 성분이 보상됨을 모의 실험과 실험을 통해 검증하였다.

• Journal of Magnetics
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• 제22권2호
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• pp.266-274
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• 2017

In this paper, torques of two motors are compared by Finite Element Analysis (FEA). One has a symmetric rotor structure and the other has an asymmetric rotor structure. The comparison shows that the asymmetric rotor structured motor has reduced torque ripple compared to the symmetric. The torque of the compared motor models was analyzed by separating into magnetic torque and reluctance torque. Through the analysis of torque component separated, it is shown that the magnetic torque and the reluctance torque compensate each other in the motor with the asymmetric structure rotor. Here "compensate" means decrementing the effect of one or more harmonics. It is shown how this compensation appears between the magnetic torque and the reluctance torque by looking into back electro motive force (emf) and the relative permeability distribution of rotor core.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.736-739
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• 1997

In recent years, there has been a renewed interest in the BLDC motor as a research subject. In this paper we inspect sources of the torque ripple, which is one of the elements causing performance depreciation of BLDC motors. Based on the inspected sources of the torque ripple, feedforward compensation methods are proposed to reduce the size of torque ripple. The effectiveness of the proposed methods is verified with experiments.

• 대한기계학회논문집A
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• 제21권2호
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• pp.252-260
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• 1997

In this paper, a friction compensation method using a disturbance observer is proposed for an impedance control of pneumatic manipulator. It is assumed that the generated torque by a pneumatic actuator can be estimated based on the pressure signals and the discharge volume. In order to improve the dynamic characteristics of the pneumatic actuator driven by meter out method, we construct the inner torque control system by feeding back the generated torque. In order to reduce the influence of disturbances comprising friction torque and parameter variations of plant, the impedance control system is constructed with a disturbance observer which estimates the disturbances based on the generated torque of pneumatic actuator, the angular velocity and the reaction torque. From some experiments, it is confirmed that the proposed control system is effective to improve the robustness for the friction torque in the impedance control of a pneumatic manipulator.

• 전력전자학회논문지
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• 제20권5호
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• pp.429-436
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• 2015

Torque ripples generate mechanical vibration at low speed and acoustic noise at high speed. The back emf harmonics of a PM synchronous motor is one of the main sources of torque ripples. To reduce torque ripples resulting from back emf harmonics, dq-axis harmonic currents that reduce the torque ripples are generally compensated to the current controller. Harmonic current compensation is effective at low speed, but it is not applicable at high speed because of the limited bandwidth of the current controller. In this study, dq-axis harmonic voltage compensation that can reduce torque ripples at high speed is proposed. The dq-axis harmonic voltages are calculated from the motor speed and the dq-axis harmonic currents. The effectiveness of the proposed method in reducing torque ripple is verified by a simulation and experiments.

• 산업기술연구
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• 제24권A호
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• pp.109-117
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• 2004

This paper presents a current control strategy to reduce torque ripple of Brushless DC Motor in commutation period with PWM pattern. The torque ripple is mainly caused by the inequality in the rate of change between rising current and decaying one during commutation. And also it is influenced by the shape of real back EMF. Therefore, in the proposed control strategy, considering real back EMF a compensation voltage is generated to equalize the rate of change in these commutating currents. And then, by providing the compensation voltage in commutation period with PWM pattern, the torque ripple can be reduced. The simulation and experimental results verify that the proposed method can reduce the torque and the current ripples significantly.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2002년도 전력전자학술대회 논문집
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• pp.285-288
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• 2002

This paper presents external load disturbance compensation that used to deadbeat load torque observer and regulation of the compensation gain by parameter estimator As a result, the response of PMSM follows that of the nominal plant. The load torque compensation method is compose of a deadbeat observer To reduce of the noise effect, the post-filter, which is implemented by MA process, is adopted. The parameter compensator with RLSM(recursive least square method) parameter estimator is suggested to increase the performance of the load torque observer and main controller The proposed estimator is combined with a high performance load torque observer to resolve the problems. As a result, the proposed control system becomes a robust and precise system against the load torque and the parameter variation. A stability and usefulness, through the verified computer simulation, are shown in this paper.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제49권10호
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• pp.701-707
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• 2000

This paper proposes a tension control to compensate friction loss using on-line friction torque observer for a continuous strip processing line. Friction loss of roller results in significant deviation of strip tension, accordingly it has an influence on the operation of other adjacent rolls. To avoid tension variation of the strip, a friction torque observer is designed in adjacent roll, which operates in speed control mode. The observed torque is added to the torque limit reference of the pay-off reel for on-line compensation of both friction loss and acceleration/deceleration torque at the same time. The simulation and experimental results show improvement of tension control performance by the proposed friction compensation method.

• 전력전자학회논문지
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• 제27권6호
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• pp.481-488
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• 2022

This study proposes compensation methods for the initial position error and torque ripple in vector control of two-phase hybrid stepping motors. Stepping motors have an asymmetrical structure due to misalignment, such as the eccentricity generated by the manufacturing and assembly process. When vector control is applied using the position information measured by an incremental encoder attached to the rotor shaft of such stepping motors, the following problems occur. First, an initial position error occurs during the forced excitation process for the initial rotor position alignment. Second, torque ripple corresponding to the mechanical rotation frequency is generated. In this study, these non-ideal phenomena that occur in vector control of the stepping motor are analyzed, and compensation methods are proposed to eliminate them. The validity of the proposed initial position error and torque ripple compensation methods is verified through experiments on a two-phase hybrid stepping motor drive system.

• Journal of Mechanical Science and Technology
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• 제14권7호
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• pp.764-772
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• 2000

In this paper, an engine-CVT integrated control algorithm is suggested by considering the inertia torque and the CVT ratio change response lag in acceleration. In order to compensate for drive torque time delay due to CVT response lag, two algorithms are presented: (1) an optimal engine torque compensation algorithm, and (2) an optimal engine speed compensation algorithm. Simulation results show that the optimal engine speed compensation algorithm gives better engine operation around the optimal operation point compared to the optimal torque compensation while showing nearly the same acceleration response. The performance of the proposed engine-CVT integrated control algorithms are compared with those of conventional CVT control, and It is found that optimal engine operation can be achieved by using integrated control during acceleration, and improved fuel economy can be expected while also satisfying the driver's demands.