• Journal of Industrial Technology
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• v.18
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• pp.439-442
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• 1998

In this paper, we firstly suggested C&D (Common mode and Differential mode) model for the representation of a stereophonic signal. Then a measure of stereophonic channel separability is defined as the ratio of differential mode energy to total energy in frequency domain. After that, a new channel separability enhancement scheme is proposed by the control of common mode rejection. Finally, some experimental results are presented in order to verify our scheme.

• Proceedings of the KIEE Conference
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• 1989.07a
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• pp.571-575
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• 1989

A position control system of D.C. Servo motor based on discrete variable structure system with sliding mode is presented. The sliding mode has been designed for a continuous system, but it is often realized in digital fashion because the complex switching logic can be easily carried out. In digital control system, the ideal sliding mode does not occur since the structure can't be switched during sampling interval. However, there can be exist a motion which is confined to a regoin including the sliding surface and proceeds to the origin along the surface. This notion is called quasisliding mode. In this paper, we introduce this control scheme to the D.C. Servo motor position control in order to reduce the chattering phenonenon.

• Proceedings of the KIEE Conference
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• 1987.11a
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• pp.552-554
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• 1987

A design principles of discontinuous control are studied and then are applied to position control of D. C. sevo drive fed by a four-quadrant chopper. Variable structure control with sliding mode gives fast dynamic response with no overshoot. And the resulting system bas good robust properties independent of the wide variations of electrical, mechanical parameters and external disturbances without any system identification. But the high frequency chatter component of control input in the sliding mode is undesirarable. A continuous control law that is a approximation to discontinuous control law is used for design.

• 제어로봇시스템학회:학술대회논문집
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• 1986.10a
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• pp.580-585
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• 1986

This paper deals with "chattering" problem in variable structure control system. For digital computer control, chattering reduction algorithm in Analog-VSC is extended to Discrete-VSC. The proposed algorithm is applied to position control of D.C Servo Motor by using 6502 .mu.-processor. The improved transient response, as well as a considerable reduction of chattering, is illustrated experimentally.imentally.

• JSTS:Journal of Semiconductor Technology and Science
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• v.16 no.5
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• pp.675-681
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• 2016

A 41dB gain control range $6^{th}$-order band-pass receiver front-end (RFE) using CMOS switched frequency translated impedance (FTI) is presented in a 40 nm CMOS technology. The RFE consists of a frequency tunable RF band-pass filter (BPF), IQ gm cells, and IQ TIAs. The RF BPF has wide gain control range preserving constant filter Q and pass band flatness due to proposed pre-distortion scheme. Also, the RF filter using CMOS switches in FTI blocks shows low clock leakage to signal nodes, and results in low common mode noise and stable operation. The baseband IQ signals are generated by combining baseband Gm cells which receives 8-phase signal outputs down-converted at last stage of FTIs in the RF BPF. The measured results of the RFE show 36.4 dB gain and 6.3 dB NF at maximum gain mode. The pass-band IIP3 and out-band IIP3@20 MHz offset are -10 dBm and +12.6 dBm at maximum gain mode, and +14 dBm and +20.5 dBm at minimum gain mode, respectively. With a 1.2 V power supply, the current consumption of the overall RFE is 40 mA at 500 MHz carrier frequency.

• 제어로봇시스템학회:학술대회논문집
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• 1988.10b
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• pp.843-847
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• 1988

A new control method for position control of D.C. servo motor based on the variable structure control is presented. The desired trajectory satisfying the given performance requirement is used as the sliding curve. And the control input forcing the system to follow the desired model system is applied. As a result the method is robust to disturbance. The performance of the proposed controller is compared with that of the conventional state feedback controller through digital computer simulation.

• Journal of Biosystems Engineering
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• v.16 no.3
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• pp.248-262
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• 1991

Simulation model was developed to analyze drying process for tray type red pepper dryer and validated by experiments. This model could predict satisfactorily temperatures and moisture contents of red pepper and temperatures of drying air during drying. Optimize algorithm was developed to search control valiables (drying air temperature, air recycle ratio and air flow rate) of red pepper dryer based on a criterion of minimizing energy consumption under the constraint conditions that statisfied carotenoid retension of at least 210mg per 100g dry matter, the moisture content of bottom layer of 15% (d.b) and drying time of less than 35 hours. Step changes in drying air temperature and air recycle ratio were considered in the optimization. In single step in control variables, the difference of the moisture content between top layer and bottom layer was great and more fan power was required. As the drying trays were exchanged when the moisture content of bottom layer reached to 100% (d.b), fifty percent of energy was saved and the difference of moisture content was little. In double step changes in control variables, optimal conditions were found by changing the step when the moisture content of bottom layer reached to 100% (d.b) (about 19.8 hours from starting drying). Optimum air flow rate was $18.1cmm/m^2$. Optimum drying air temperature and air recycle ratio in the first step was $55.8^{\circ}C$ and 0.80, and in the second step $65.6^{\circ}C$ and 0.88, respectively. In triple step changes in control variables, the optimal conditions were found by changing the steps when the moisture content of bottom layer reached to 250% (d.b) and 150% (d.b). Optimal air temperatures were $66.2^{\circ}C$, $58.4^{\circ}C$ and $66.9^{\circ}C$, and optimal air recycle ratios were 0.778, 0.785, 0.862 at each step, respectively. Optimal air flow rate was $18.9cmm/m^2$. The best operating mode was triple step mode considering energy consumption, drying time, fan power, and quality of dried red pepper. When the triple step mode was used to dry the red pepper, the energy consumption was about 16.5%~57.2% less than that of the single step mode and the drying time was 6.6 hours shorter than that of the double step mode.

• Journal of Power Electronics
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• v.9 no.4
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• pp.604-611
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• 2009

A dP/dV feedback-controlled MPPT (Maximum Power Point Tracking) method for photovoltaic power systems using II-SEPIC (Isolated Inverse-SEPIC; Single Ended Primary Inductance Converter) is presented and a current-mode dP/dV feedback-controlled MPPT method is devised to apply for the PV power converter system. A control strategy for the current-mode dP/dV feedback control system is developed in this paper and the proposed MPPT shows relatively satisfactory dynamics against rapidly changing insolation conditions. In order to verify the validity and effectiveness of the proposed method, simulations and experiments of the PV power system using II-SEPlC converter are performed. These simulation and experiment results show that the proposed method enables the PV power system to extract maximum power from the photovoltaic module against the solar insolation variation.

• Proceedings of the KIEE Conference
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• 1988.11a
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• pp.72-75
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• 1988

In the point-to-point motion on servo system, the control mode which minimizes the performance index including, the impact of end point, time and energy, is proposed. The proposed control mode applied to the feed-back control system of D.C motor and then had a computer simulation. This control mode had less the impact of end point, stedy state error, time and energy than the bang-bang or the saturating- proportional control mode.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.51 no.12
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• pp.571-576
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• 2002

This paper is to develop jumping ring system with three sensor arrays and to control levitated ring using dynamic neural mode. Placing an aluminum ring on the core and switching on an AC source causes the ring to jump in the air due to induced currents. The educational system is composed of 40th optical sensor array, encode circuit, 89C51 microprocessor and control board. The control board consists of power IC, and phase controller. Real time process is present to obtain a height of levitated ring for three different sensor arrays. Based on the educational system and the proposed dynamic neural mode, the height of levitation of the ring is controlled by reference signals. This paper focuses on real system controls using the dynamic neural mode with on line learning algorithm.