• Proceedings of the KIPE Conference
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• 2011.07a
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• pp.370-371
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• 2011

This paper presents a control algorithm that minimizes the DC-link capacitance by decreasing the capacitor current. The capacitor current can be nullified by a feedback compensation term which is calculated from the power balance in the AC/DC converter. As a result, voltage variation in the DC-link is reduced further, which makes a large reduction in the size of DC-link capacitors which are expensive and have limitations in life time. Simulations are performed with two 80uF DC-link capacitors, which can be replaced by film capacitors.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.43 no.2
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• pp.215-225
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• 1994

In this paper, a performance evaluation of different current regulators for induction motor drive systems fed by IGBT inverter is presented. The twoparts of current regulation are considered : current error compensation part, voltage modulation part. The characteristics of hysteresis, synchronous PI, decoupled PI, predictive, deadbeat and stage feedback controllers are analyzed and the steady-state performances and transient responses of current regulation are well compared through the simulation and experimental results.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.367-370
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• 1991

There are many kinds of drift source in angular velocity feedback stabilization system. We discussed and analyzed the source of drift, and suggest the drift compensation method for null drift system. In this paper, the performance of drift compensators is tested and proved by real 2 axis mirror stabilization system and computer simulation.

• 제어로봇시스템학회:학술대회논문집
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• 1987.10b
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• pp.32-35
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• 1987

An adaptive control scheme has been recognized as an effective approach for a robot manipulator to track a desired trajectory in spite of the presence of nonlinearties and parameter uncertainties in robot dynamic models. In this paper, an adaptive control scheme for a robot manipulator is proposed to design the self-tuning controller which combines the pole placement with the extended linearized perturbation model. And this control scheme has two components: a feadforward control and a feedback compensation control. Based on this, the controller is demonstrated by the simulation about position control of a three-link manipulator with payload and parameter uncertainty.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.642-647
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• 1998

A new small-signal model for the controlled on-time boost power factor correction (PFC) circuit is presented. The proposed small-signal model is valid up to high frequencies over lKHz. The model can be used in designing the voltage feedback compensation of PFC circuits, the control bandwidth of which is maximized with auxiliary means of removing the low-frequency ripple from the output. The accuracy of the model is confirmed by a 200W experimental hardware

• International Journal of Control, Automation, and Systems
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• v.6 no.4
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• pp.583-595
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• 2008

In this paper, we introduce a fuzzy nonlinear feedback approach to the control of a class of chaotic dynamical systems. The fuzzy Parallel Distributed Compensation with Reduced Rule Base approach (PDC_RRB) is proposed. The design procedure is conceptually simple and considered to a nonlinear optimal and robust control problem due to the nonlinear nature of the Takagi-Sugeno (TS) fuzzy system. Simulation results are provided to show the effictiveness of the proposed methodology.

• Proceedings of the KIPE Conference
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• 2015.07a
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• pp.229-230
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• 2015

This paper presents practical details about control-loop design and dynamic analysis for a voltage-mode controlled isolated double step-down DC-DC converter. Graphical loop gain method is used to design the feedback compensation and analyze the closed-loop performance of isolated double step-down DC-DC converter. The results of the control design and closed-loop analysis are validated by experiments on a prototype converter.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.8
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• pp.757-764
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• 2015

Mathematical modeling of focal plane compensation device in the small earth-observation satellite camera has been conducted experimently for compensation of micro-vibration disturbance. The PZT actuators are used as control actuators for compensation device. It is quite difficult to build up mathematical model because of hysteresis characteristic of PZT actuators. Therefore, the compensation device system is assumed as a $2^{nd}$ order linear system and modeled by using MATLAB System Identification Toolbox. It has been found that four linear models of compensation device are needed to meet 10% error in the input frequency range of 0~50Hz. These models describe accurately the dynamics of compensation device in the 4 divided domains of the input frequency range of 0~50Hz, respectively. Micro-vibration disturbance can be compensated by feedback control strategy of switching four models appropriately according to the input frequency.

• Physical Therapy Korea
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• v.18 no.2
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• pp.67-75
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• 2011

The purpose of this study was to investigate the effects of virtual reality (VR) therapy with compensation inhibition and feedback (CIF) on upper extremity function in chronic stroke patients. Seven chronic stroke patients participated in this study, which was a randomized controlled trial with a crossover design. Self upper extremity exercise, conservative VR therapy, and VR therapy with CIF were performed for one hour per session, 5 times per week, over a 3 week period. The main outcome measures involved range of motion (ROM) including shoulder, elbow, and wrist joints, a Manual Function Test (MFT), and a Motor Activity Log (MAL). Data were calculated as posttest and pretest changes in every session and were analyzed using Friedman and Wilcoxon signed-rank tests at p<.05. The results were as follows: 1) Statistically significant increase in ROM measurements of shoulder and elbow joints were seen with VR therapy with CIF compared to VR therapy and self upper extremity exercise (p<.05), whereas no significant increasing was noted for the wrist joint (p>.05). 2) Statistically significant increase in the MFT was seen with VR therapy with CIF compared with VR therapy and self upper extremity exercise (p<.05). 3) VR therapy with CIF also resulted in statistically significant increase in both activity of use (AOU) (p<.05) and quality of movement (QOM) (p<.05) on the MAL test when compared with VR therapy and self upper extremity exercise, respectively. In conclusion, VR therapy with CIF was more effective than conservative VR therapy and self upper extremity exercise in improving the upper extremity function in hemiplegic patients with chronic stroke.

• The Transactions of the Korean Institute of Power Electronics
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• v.4 no.1
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• pp.50-56
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• 1999

This paper presents consideration on validity of instantaneous correlation power theory. The proposed power theory is defined and analyzed by time domain approach, thus it is easy to understand and instrument. The power is decomposed into active, fundamental reactive and harmonics components based on the autocorrelation and crosscorrelation signal techniques between voltage and current waveforms. On the compensation property, active power filter deal with three components only. Also, for real time control of active power filter, the power models with difficult concept are not cost effective. To verify the validity of the instantaneous correlation power theory, experimental work for voltage type DSP based active power filter is achieved. The power of thyristor controlled motor drives is decomposed into three orthogonal components by proposed power theory. From compensation results, validity of proposed theory is confirmed. feedback controller needs the information on some motor parameters. New recursive adaptation algorithms for rotor resistance and mutual inductance which can be applied to our nonlinear feedback controller are also presented in this paper. The recursive adaptation algorithms make the estimated values of rotor resistance and mutual inductance track their real values. Some simulation and experimental results show that the adaptation algorithms are robust against the variation of stator resistance and stator inductance.