• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.10B
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• pp.1769-1776
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• 2000

In this paper a new method is proposed to identify a modulation method in the case of unknown digitally modulated input signals. The proposed identification method is implemented with an artificial neural network which is based on characteristic feature extracted from the instantaneous amplitude the instantaneous phase and the instantaneous frequency of the input signals. The proposed method was simulated with 9 type signals (ASK2, FSK2, FSK4, PSK2, PSK4, PSK8, QAM8, QAM16) in a noisy communication environment. The results show that the artificial neural network can accurately recognize all kinds of patterns.

• Journal of Korea Water Resources Association
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• v.36 no.4
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• pp.575-586
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• 2003

In case of continuous input of a pollutant, dispersion characteristics do not change much with changing dispersion coefficient, but that of an instantaneous input is very sensitive to the changes of dispersion coefficient. The characteristics of behavior of instantaneous input of a pollutant at the downstream of Han river were analyzed in this paper Field measurement of hydraulic and water quality factors at the downstream of Han river were conducted at low flow condition. The hydraulic factors were used to estimate the longitudinal dispersion coefficient, and the reasonable empirical equations for longitudinal dispersion coefficient at the downstream of Han river were suggested. The measured concentrations of BOD were closely matched with the calculated ones from RMA-4 model. In case of instantaneous input, range of dispersion, transport pathway and the traveltimes of the first and maximum concentration with variation of the longitudinal dispersion coefficients and water levels of downstream boundary were evaluated in this paper.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.274-277
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• 1996

Vector controlled PMAC(Permanent Magnet AC) motor, with rare-earth permanent magnet, are suitable for servo system demanding fast speed response. However, abrupt acceleration and deceleration control for fast response requires big instantaneous input power. So general PI control of PMAC motors can't be applied for limited power supply system like airplane or portable equipment because of input power fluctuation. Proposed technique to restrain instantaneous input power use variable power limit depends on airgap flux power. Stability check for proposed system is done.

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.213-214
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• 2014

This paper compares two instantaneous reactive power definitions in DFIG wind turbine with a back-to-back three-level neutral-point clamped voltage source converter under unbalanced grid conditions. In general, conventional definition of instantaneous reactive power is obtained by taking an imaginary component of complex power. The other definition of instantaneous reactive power can be developed based on a set of voltages lagging the grid input voltages by 90 degree. A complex quantity referred as a quadrature complex power is defined. Proposed definition of instantaneous reactive power is derived by taking a real component of quadrature complex power. The characteristics of two instantaneous reactive power definitions are compared using the ripple-free stator active power control algorithm in DFIG. Instantaneous reactive power definition based on quadrature complex power has a simpler current reference calculation control block. Ripple of instantaneous active and reactive power has the same magnitude unlike in conventional definition under grid unbalance. Comparison results of two instantaneous reactive power definitions are verified through simulation.

• The Transactions of the Korean Institute of Power Electronics
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• v.22 no.5
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• pp.457-462
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• 2017

This paper proposes a digital power control of the LLC resonant half-bridge inverter for high power microwave oven application. Conventional half-bridge inverter for driving a microwave oven uses a hardware-based power control method which varies the frequency according to the AC source voltage. In this case, it is difficult to control the output power according to the variation of the load status of magnetron. The proposed power control consists of an instantaneous current generator and a current controller. Instantaneous current generator makes an instantaneous current reference from power command using input voltage information. Current controller controls input current which has an information of status of magnetron. The proposed power control does not require any compensation algorithm for the change of the load status of the magnetron and change of input voltage. The validity of the proposed method for the control of the change of input voltage and frequency is verified by both simulation and experiment.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.179-183
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• 2001

This paper presents a simple current control strategy for matrix converters based on the extension of PWM method for inverters. A novel and efficient PWM algorithm is developed. The algorithm is verified through simulation and experiments employing a 2-kVA prototype. The results of simulation and experiment prove the instantaneous control capability of the output current with the sinusoidal input current.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.721-723
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• 1993

A PWM switching control strategy based on instantaneous integration concept for reducing hamonic components of inverter system with fluctuating input voltage is presented. Applying this strategy to single phase full bridge PWM inverter through bipolor switching method and unipolor switching method, reduction of hamonic components of output voltage and current is demonstrated through simulation. The system operation is examined and confirmed by experiments.

• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.49-50
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• 2010

In this paper, we propose a boost type inverter system for the compensation of instantaneous voltage sag. The system compensate instantaneous voltage sag which magnitude is higher than 10[%] of normal input voltage. When input voltage is higher than 90[%] of normal value, the switch in boost converter is not operated and output voltage is controlled by modulation amplitude in PWM inverter.

• Journal of the Korean Institute of Telematics and Electronics T
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• v.35T no.3
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• pp.25-30
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• 1998

In this Paper, a new method is proposed to identify a modulation method in the case of unknown digitally modulated input signals. The proposed identification method is implemented with an artificial neural network which is based on characteristic features extracted from the instantaneous amplitude, the instantaneous phase and the instantaneous frequency of the input signals. The proposed method was simulated with 8 type signals in a noisy communication environment. The results show that the artificial neural network can accurately recognize all kinds of patterns.

• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.197-200
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• 2001

This paper presents a PWM buck AC-AC converter with instantaneous compensation for input voltage sag and surge. The presented converter use commercial IGBT modules and its output voltage is regulated so as to remain constant AC output voltage. The feedforward control technique is also proposed to establish instantaneous duty level change whereby stable output voltage will be retained. This paper show the characteristics and control algorithm of the converter through various PSPICE simulations.