• Journal of the Korean Professional Engineers Association
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• v.22 no.4
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• pp.12-16
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• 1989

This paper presents a n analysis of the output voltage waveforms of the double sinusoidal modulated PWM inverter, and are studied on the driving characteristics through the 3 phase induction motor using 6502 microcomputer. The double sinusoidal modulated waves are produced during the interval 4$\pi$/3 [rad] for one cycle, and the switching loss can be reduced. The amplitude of fundamental wave of double sinusoidal modulated PWM inverter is 1.15 times higher than that of the sinusoidal PWM inverter, but the practical measured value by FFT analyzer is 1.13 times.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.1064-1066
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• 2001

In this paper, the harmonic components generated by those two sources are analyzed separately based on the transfer function and shown as the closed form considering the switching frequency, speed of the control processor, gain of the controller, and the inductor and capacitor value of L-C filter. A design procedure is described with one flow chart and explained step by step.

• 제어로봇시스템학회:학술대회논문집
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• 1988.10a
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• pp.299-304
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• 1988

This paper describes the application of the variable structure control(VSC) concept for the position control of electro-hydraulic servomtor system. The basic philosopy of VSC is that the structure of the feedback control is altered as the state crosses discontinuity surfaces in the state surface with the result that certain desirable properties are achieved. The switching of the control function yields total(or selective) invariance to system parameter variations and disturbances, and closed loop eigen value placement in time-varing and uncertain systems.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1807-1809
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• 1996

The axial discharge at switching operations of EHV $SF_6$ disconnector can lead to the breakdown to the enclosure. Precursor in periphery zone leads to formation of leader over some time delay. Injected charge value depends on electric field and gap geometry. The calculation method for parameters of $SF_6$ insulation for DS in EHV-GIS is suggested by using the new criterion of leader inception in connection with periphery field nearby the boundary of streamer zone.

• The Pure and Applied Mathematics
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• v.18 no.2
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• pp.129-139
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• 2011

We consider an optimal trading rule in this paper. We assume that the underlying asset follows a mean-reverting process and the transaction consists of one buying and one selling. To maximize the profit, we find price levels to buy low and to sell high. Associated HJB equations are used to formulate the value function. A verification theorem is provided for sufficient conditions. We conclude the paper with a numerical example.

• Proceedings of the KIEE Conference
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• 1987.07a
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• pp.407-410
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• 1987

A layout design concept which suppress the substrate current generated during the switching transients of an CMOS inverter is presented. The amount of hot carriers and the peak value of substrate current can be reduced by changing the device geometry ratio of driver and load device of an CMOS inverter.

• Journal of the Korean Solar Energy Society
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• v.32 no.spc3
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• pp.255-261
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• 2012

Since PV PCS uses output current sensor for ac output current control, the sensor's sensing value includes unnecessary offset inevitably. If PV inverter is controlled by the included offset value, it's output current will generate DC offset. The DC offset of output current for trans-less PV inverter is fatal to grid, which results in saturating grid side transformer. Usually DSP controller of PV inverter reads several times sensing value during initial operation and, finally, it's average value is used for offset calibration. However, if temperature changes, the offset changes, too. And also, the switch device is not ideal, both each switching element of the voltage drop difference and on & off time delay difference generate DC offset. Thus, to compensate for deadtime and the switch voltage drop, feedback control by output current DC offset should be provided to compensate additional distortion of the output current. The validity of the proposed method is confirmed through PSIM simulation.

• Journal of Korea Society of Industrial Information Systems
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• v.18 no.5
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• pp.81-92
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• 2013

The satellite includes many release mechanisms such as solar array deployment, antenna deployment, cover to protect contamination in scientific equipment, pyro value of the propulsion subsytem, and bypass device in Li-Ion cell module. A drive the initiators is a critical to the successful mission because the initiators of release mechanism driving by the pyrotechnic circuit is operated in single short. The pyrotechnic circuit has to provide switching network for safety. A typical switching network has defect consisting of high current rating fire switch to handle switching transient current during fire the initiator. The pyrotechnic circuit is required some form of power conditioning to reduce the peak power demanded from the bus if the initiators are to be fired from the main bus. This paper design a pyrotechnic circuit synchronized to the fire-command to activate the fire switch to overcome use high current rating fire switch to handle switching transient current during fire the initiator. The pyrotechnic circuit provides a current limited widow pulse for fire current synchronized to the fire-command to insure that fire switch will only carry the current but never switch it. The current limited widow pulse for fire current can be possible to use low current rating and light mass switch in switching network. The current limit function in the pyrotechnic circuit reduces supply voltage to initiator and provides the effect of power conditioning function to reduce peak bus power. The pyrotechnic circuit to apply satellite development on geostationary orbit is verified the function by test in development model.

• Proceedings of the KIPE Conference
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• 2003.07a
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• pp.54-57
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• 2003

A new non linear, mean value, instantaneous following control technique to design half bridge converter is proposed in witch control principle uses characteristic that reset time of analog integrator is inverse proportion In input voltage. It is Important characteristic that compensation and follow-up control time are same with switching frequency. Is completed in one cycle that base control frequency. Have excellence characteristic that follow in order instruction value exactly stationary state as well as transient state. Half bridge converter that apply this control principle can know that have stabilize and excellence characteristic. This technique is verified through an experiment, and know that experiment result and theory agree well.

• Biotechnology and Bioprocess Engineering:BBE
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• v.11 no.2
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• pp.110-115
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• 2006

We conducted a sensitivity analysis of the simulated moving bed (SMB) chromatography with the case model of the separation of two amino acids phenylalanine and tryptophan. We consider a four-zone SMB chromatography where the triangle theory is used to determine the operating conditions. Competitive Langmuir isotherm model was used to determine the adsorption isotherm. The finite difference method is used to solve nonlinear partial differential equation (PDE) systems numerically. We examined the effects of alterations in the operating conditions(feed-extract, feed-raffinate, eluent-extract, eluent-raffinate, recycle, and switching time) and the adsorption isotherm parameters (Langmuir isotherm parameters a and b) on SMB efficiency. The variation range of operating conditions and Langmuir isotherm a was between -50 and 50% of original value and the variation range of the Langmuir isotherm b was between $2.25^{-5}$ and $2.25^5$ times of original value.