• Journal of the Optical Society of Korea
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• v.18 no.6
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• pp.646-649
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• 2014

Performances of spectrum-sliced channels are strongly affected by their relative intensity noise (RIN). We use polarization-independent optical modulators (PIOMs) for spectrum-sliced channels to suppress their RIN. The PIOM driven by a high sinusoidal voltage signal evenly redistributes optical frequency components in the spectral domain and reduces the RIN. It can be used at a broadband light source (BLS) output to produce spectrum-sliced channels having lower RIN values. Also, it can be used for each spectrum-sliced channel within each optical network unit (ONU). In our experiment, where 12.5-GHz-spaced spectrum-sliced channels are used in 1-GbE speed, the use of PIOM at the BLS output reduces the bit error rate (BER) of the spectrum-sliced channel by more than an order of magnitude. The use of PIOM within the ONU reduces the BER by approximately 3 orders of magnitude.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.4
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• pp.15-26
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• 1998

Full car model is needed for investigating as a entire dynamics of vehicle. In this study, 7DOF of full car model's dynamics is selected. This paper proposes the output feedback controller based on optimal control theory. Input data and output data from the optimal controller are used for neural network system identification of the suspension system. To do system identification, neural network which has robustness against nonlinearities and disturbances is adapted. This study uses back-propagation algorithm to train a multil-layer neural network. After obtaining a neural network model of a suspension system, a neuro-controller is designed. Neuro-controller controls suspension system with off-line learning method and multistep ahead prediction model based on the neural network model and a neuro-controller. The optimal controller and the neuro-controller are designed and then, both performances are compared through. For simulation, sinusoidal and rectangular virtual bumps are selected.

• Journal of the Korean Institute of Telematics and Electronics
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• v.9 no.5
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• pp.12-18
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• 1972

The relation between output SNR and mth harmonic generation is determined for nonlinear system of zero memory type, half wave and the nth power law devices with narrow band form of the unmodulated sinusoidal wave plus zero mean and stationary gaussian noise input. It is found that the optimum generation condition for harmonic component at a small input of SNR is m and n equal 2, while for large input SNR is always n equals 2.

• Proceedings of the KIEE Conference
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• 1995.11a
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• pp.242-245
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• 1995

In this paper the multiple three rectifiers for the power factor correction are proposed, analyzed and designed. The multiple three phase rectifiers draw sinusoidal ac currents from the ac voltage sources with nearly unity input power factor and operate with PWM making the control circuit simple and system cost low. Outstandingly it reduces the rated power capacity of devices and the input filter size by reducing input current ripples. Moreover design rules can be obtained from input and output current equations. With the proposed rules, input power factor and output power capacity are determined approximately. Finally these design rules are verified with computer simulations.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.12
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• pp.2396-2401
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• 2009

The three-phase buck-boost DC-AC inverter generates three alternating output voltages as the differential voltage of three DC-DC individual buck-boost converters. Three converters are driven with three DC-biased and 1200 phase-shifted sinusoidal references. The peak value of the inverter alternating output voltage can be larger or smaller than the value of the direct input voltage. In this paper, a three-phase buck-boost DC-AC inverter is designed and implemented on a prototype with digital controller using a microcontroller.

• Journal of Advanced Navigation Technology
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• v.3 no.1
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• pp.44-51
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• 1999

In this paper we proposed an output voltage regulation scheme of a single-phase PWM inverter used to obtain a 400 Hz sinusoidal AC voltage for an aircraft. The fuzzy-inference control scheme is designed to achieve good output voltage tracking in the presence of load change or parameter variations. The PWM gate signals are determined by the fuzzy-inference controller using the error between the reference voltage and the feedback voltage and the derivative of error. The tracking performance of.

• Journal of Power Electronics
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• v.9 no.2
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• pp.173-179
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• 2009

This paper proposes a new three-phase diode rectifier system with a sinusoidal input current at unity power factor and a regulated and isolated output voltage at low level. The inherent natural wave-shaping capability of the reduced kVA polyphase transformer together with an active current wave-shaping technique results in a significant reduction of input and output filter requirements associated with switching ripple and EMI. The operation principles are described along with a design example and a comparative evaluation. Experimental results on a 1.5kW prototype are provided to validate the proposed concept.

• Journal of Power Electronics
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• v.12 no.2
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• pp.258-267
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• 2012

An interleaved single-stage AC/DC converter with a boost converter and an asymmetrical half-bridge topology is presented to achieve power factor correction, zero voltage switching (ZVS) and load voltage regulation. Asymmetric pulse-width modulation (PWM) is adopted to achieve ZVS turn-on for all of the switches and to increase circuit efficiency. Two ZVS half-bridge converters with interleaved PWM are connected in parallel to reduce the ripple current at input and output sides, to control the output voltage at a desired value and to achieve load current sharing. A center-tapped rectifier is adopted at the secondary side of the transformers to achieve full-wave rectification. The boost converter is operated in discontinuous conduction mode (DCM) to automatically draw a sinusoidal line current from an AC source with a high power factor and a low current distortion. Finally, a 240W converter with the proposed topology has been implemented to verify the performance and feasibility of the proposed converter.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.51 no.3
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• pp.125-132
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• 2002

This paper presents a single-phase 3-level PWM inverter to alleviate the harmonic components of output voltage and current under the conditions of identical supply DC voltage and switching frequency to the conventional inverter. Operational principles and analysis are performed, and the switching functions are derived. Deadbeat controller is also designed and implemented for the inverter to keep the output voltage being sinusoidal and to have the high dynamic performances even in the cases of load variations and the partial magnetization of filter inductor. The validity of proposed inverter is proved from the simulated and experimented results.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.6
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• pp.322-329
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• 1999

In this paper a practical series-parallel compensated UPS is suggested, which has high input power factor and sinusoidal output voltage regulation capability. Compared to conventional cascaded UPS, the size can be reduced significantly with high quality input and output waveforms. The front converter and the main inverter can be considered decoupled, hence the front converter and the main inverter can be designed independent of each other. In this paper, analysis and experimental results for an l KVA prototype are presented.