• Proceedings of the KIPE Conference
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• 2011.11a
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• pp.219-220
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• 2011

In this paper, 300[W] class boost type single phase inverter system which can compensate voltage sag was designed. If the voltage sag has appeared in input voltage, the boost converter would be operated to compensate it. The system is designed for that the THD of ouput voltage is below 5[%] and steady state error of output voltage is below 1[%]. The system was verified through experiments.

• Proceedings of the KSPS conference
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• 2002.11a
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• pp.191-194
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• 2002

Lip-reading technology that is studied them is used to compensate speech recognition degradation in noise environment in bi-modal's form. The most important thing is that search for correct lips area in this lip-reading. But, it is hard to forecast stable performance in dynamic environment. Used RASTA filter that show good performance to remove noise in the speech to compensate. This filter shows that improve performance of using time domain of digital filter. To this experiment observes performance of speech recognition only using image information, service chooses possible 22 words and did recognition experiment in car. We used hidden Markov model by speech recognition algorithm to compare this words' recognition performance.

• International Journal of Precision Engineering and Manufacturing
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• v.4 no.5
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• pp.5-14
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• 2003

Tracking control schemes on the precise mechanical system in presence of nonlinear dynamic friction is proposed. A nonlinear dynamic friction is regarded as the bristle friction model to compensate fer effects of friction. The conventional SMC method often shows poor tracking performance in high-precision position tracking application since it cannot completely compensate for the friction effect below a certain precision level. Thus to improve the precise position tracking performance, we propose the SMC method combined with the disturbance observer having tunable transient performance. Then this control scheme has the high precise tracking peformance as well as a good transient response when it is compared with the conventional SMC method and the similar types of observers, The experiment on the XY ball-screw drive system with the nonlinear dynamic friction confirms the feasibility of the proposed control scheme.

• The Transactions of the Korean Institute of Power Electronics
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• v.18 no.6
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• pp.507-514
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• 2013

In this paper, the proposed charging algorithm is converted from the charging mode to compensate the transient state in the solar battery charging system. The maximum power point tracking (MPPT) control methods and the various charging algorithms for the optimal battery charging are reviewed. The proposed algorithm has excellent transient characteristics compare to the previous algorithm by adding the optimal control method to compensate the transient state when the charging mode switches from the constant current mode to the constant voltage mode based on the conventional constant-current constant-voltage (CC-CV) charging algorithm. The effectiveness of the proposed method has been verified by simulations and experimental results.

• The Transactions of the Korean Institute of Power Electronics
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• v.23 no.4
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• pp.265-272
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• 2018

This paper proposes a new control method for the supercapacitor (SC) to compensate the pulsed load and to enhance the power quality of the DC microgrid. By coordinating the operating frequency, the SC is controlled to handle the surge current, while the low-frequency current component is dealt with by the remaining sources in the system. The operation mode of the SC unit is automatically changed based on the state of charge and DC bus voltage level. Meanwhile, the mismatch in the power demand is covered by the SC unit by regulating the DC bus voltage level. The effectiveness of the proposed method is verified experimentally by the prototype with two distributed generators and one SC unit.

• Proceedings of the KIPE Conference
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• 2011.07a
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• pp.352-353
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• 2011

This paper proposes a cascaded boost type inverter system to compensate the voltage sag. If the voltage sag has appeared in input voltage, a cascaded boost converter would be operated to compensate voltage sag. The output voltage is kept constant by a direct-quadrature frame controller in the single-phase PWM inverter. The validity of proposed system is verified by simulation on the 300W cascaded boost type inverter system.

• The Journal of Information Technology
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• v.10 no.3
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• pp.47-58
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• 2007

In this paper, we designed and manufactured the distortion-cancellation module which is able to compensate thermal-noise distortion by software. The distortion-cancellation algorithm not only bring forth system non-linear distortion by input level but also bring compensate component of distortion by thermal to get rid off distortion from now on. After TMS 320C6711 DSP to recognize our algorithm, we manufactured the module for every kinds of system. To evaluate efficiency of the distortion-cancellation module, we designed and manufactured communication system. By measured result, if system output power is -3dBm equally, 12dB of ACLR has improved in 1MHz away from a center frequency, and also gain has increased up to 0.5dB.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1640_1641
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• 2009

Dynamic friction and force ripple are the most predominant factors that affect the positioning accuracy of permanent magnet synchronous motor(PMSM) servo drives system, and it is desirable to compensate them in finite time with a continuous control law. In this paper, based on LuGre dynamic friction model, a robust adaptive skidding mode controller is proposed to compensate the nonlinear effect of friction and force ripple. The controller scheme consists of a PD component and a robust adaptive sliding mode controller for estimating the unknown system parameter. Using Lyapunov stability theorem, asymptotic stability analysis and position tracking performance are guaranteed. Simulation results well verify the feasibility and the effectiveness of the proposed scheme for high0precision motion trajectory tracking.

• Journal of Mechanical Science and Technology
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• v.15 no.6
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• pp.699-708
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• 2001

This paper presents a new approach to the AFR (Air-to-Fuel Ratio) control problem, which is based on the wide-band oxygen sensor output. The dedicated nonlinear controller is based on the feedback lineaization technique. It is well known that the feedback linearizing control technique requires an exact model of the plant for the cancellation of plant nonlinearities. A sliding mode control scheme is applied which can effectively compensate the modeling uncertainties. The measurement time delay of an oxygen sensor limits the gain of the feedback controller. Hence, time delay compensation procedure is necessary for the improvement of control performance. The Smith predictor is adopted to compensate the effects of time delay. The simulation and experimental results show that the proposed controllers can effectively reduce the transient peaks of AFR in spite of fast tip-in and tip-out maneuvers of the throttle.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.9 no.4
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• pp.75-84
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• 2000

The main goal of our research is to compensate the milled surface errors induced by the tool deflection effects, which occur during the milling process. First, we predict cutting forces and tool deflection amount. Based on predicted deflection effects, we model milled surface shapes. We present a compensation methodology , which can generate a new tool trajectory, which is determined so as to compensate the milled surface errors. By considering manufacturing tolerance, tool path compensation is generalized. To validate the approaches proposed in this paper, we treat an illustrative example of profile milling process by using flat end mill. Simulation and experimental results are shown.