• 대한전기학회논문지
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• 제36권8호
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• pp.547-553
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• 1987

A new control method is proposed for PWM ac chopper whcih can have the features of both linear control of the fundamental voltage and complete elimination of the harmonics up to specified order. Through theoretical investigation of the proposed method, it is found that both input and output characteristics can be improved better than those of the conventional methods. Also the newly modified triangular carrier wave is suggested to perform the above features over full control range and to implement the control circuit easily. To evaluate the performances of the proposed PWM method, the comparsion with the conventional PWM technique is made and the exterimental results are suggested.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1999년도 전력전자학술대회 논문집
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• pp.295-298
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• 1999

In this paper, the diode bridge-type ZVT(Zero-Voltage Transition) inverter is proposed. It consists of one auxiliary switch, three resonant inductors and six blocking diodes. So, the advantage of the proposed topology is the reduction of the auxiliary switch. The topology of the proposed ZVT inverter is analyzed with a description of the control conditions based on the load current. Therefore, this paper two control algorithms were discussed. A variable resonant pattern control algorithm by using load current feedback and a resonant period control algorithm by using resonant inductor current feedback is proposed in order to achieve the ZVT switching condition in full control range and the reducing current spike main switches cause by reverse recovery problem.

• 제어로봇시스템학회논문지
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• 제18권8호
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• pp.774-779
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• 2012

We design and implement a RTT (Round Trip Time) based TCP (Transmission Control Protocol) for USN (Ubiquitous Sensor Network). We adopt a basic update algorithm for window size from FAST TCP that uses the queuing delay at link as the congestion measure. The designed TCP estimates the queuing delay at link from the measured RTT in the network layer, and updates the window size based on the estimated queuing delay. The designed TCP allows to utilize the full capacity of USN links and avoids the waste of the given link capacity that is common without the flow control in the transport layer. The experiment results show that the window size of the sender converges within a small range of variations without any packet loss, and verify the stability and performance of the designed TCP.

• 한국지열·수열에너지학회논문집
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• 제6권2호
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• pp.1-7
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• 2010

The objective of this study is to find the optimal control algorithm of a hybrid Plant, which is combined by renewable energy plant of the GSHP(Geothermal Source Heat Pump) and the normal plant (Chiller, boiler). The work presented in this study was carried out in the EnergyPlus(Version 2.0). The EnergyPlus was modified in order to simulate the hybrid plant. The plant system was controlled by the load-range-based operation in which schemes select a user specified set of equipment for each user specified range of a particular simulation condition. In the use of the load-range-based operation, four kind of control cases were defined and simulated in order to obtain the optimal control algorithm of the hybrid plant. The result showed that the Case 2 was the optimal control algorithm which used the GSHP as a base operating plant and the normal plant as an assistant operating plant. Even though the normal plant was operated in full load and the renewable energy plant of the GSHP was operated in partial load, the annual energy consumption of the normal plant was larger than that of the GSHP plant.

• Journal of Advanced Marine Engineering and Technology
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• 제19권1호
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• pp.71-81
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• 1995

In this paper, a new speed control scheme for induction motor drives that regular sampled PWM and harmonic elimination switching pattern over the full range of output speed is presented. The proposed scheme(hybrid scheme) provides three mode and guarantees smooth voltage boost. A detailed description of the scheme, along with the relalization aspect, is described. Moreover, methods of compensating for dead time and optical transmission system of drive signal are proposed and investigated. Finally, experimental investigation of hybrid scheme is presented.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.166.1-166
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• 2001

Anti-lock Braking System(ABS) is a device which prevents the wheels form locked up under emergency braking of a vehicle. So it helps the vehicle to maintain the steerability and shortens the braking distance by maintaining optimal frictional force during braking since the tire road slip is controlled in acceptable range. Recently, ABS is accepted as a standard equipment in vehicles, especially in commercial vehicles(bus and trucks). Commercial vehicles don´t use hydraulic lines but use pneumatic lines for braking system mostly. In this paper, ECU(Electronic Control Unit) for the anti-lock braking system of a commercial vehicle which is equipped with a full-air brake system and its control algorithms are presented. In this algorithm wheel speed acceleration flags and wheel slip flags are defined ...

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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• pp.687-693
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• 1998

An improved zero voltage and zero current switching (ZVZCS) full bridge (FB) PWM converter is proposed to solve the problems of the previously presented ZVACS-FB-PWM converter with secondary active clamp such as narrow ZVS range of leading-leg switches [6]. By adding an auxiliary inductor in between the leading-leg and separated input source voltages, the ZVS of leading leg switches can be extended to the whole line and load ranges, which eliminates unwanted hard switching of clamp switch and simplifies its control. The principle of operation is explained and analyzed. The features and design considerations of the proposed converter are also illustrated and verified on a 3 kW, 100 KHz IGBT based experimental circuit.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2010년도 하계학술대회 논문집
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• pp.45-46
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• 2010

In this paper, the static overmodulation is proposed for the 2-phase full bridge inverter. The overmodulation strategy increases a fundamental output voltage and improves a voltage utilization up to the maximum in the overmodulation range. To maintain a linearity of the relation between a reference voltage and a fundamental output voltage, this paper suggests a compensation voltage, whose magnitude or phase is modified to the proposed control scheme. Simulation and experimentation results demonstrate the effectiveness of the proposed algorithms.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.514-514
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• 2000

In this article, the realization of a precision full-wave rectifier circuit for analog signal processing, which operates throughout in the current domain, is presented. The circuit makes use of a MOS class B/AB configuration, and provides a wide dynamic range and wide-band capability. The rectifier has a simple circuit configuration and is suitable for implementing in CMOS integrated circuit form as versatile building block. The characteristic of the circuit exhibits a low distortion en the output signal at low level input signal. PSPICE simulation results demonstrating the characteristic of the proposed circuit are included.

• 전기학회논문지
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• 제63권5호
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• pp.622-628
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• 2014

This paper presents the SOC-based control strategy of BESS(Battery Energy Storage System) for providing power system frequency regulation in the bulk power systems. As the life cycle of BESS would be shortened by frequent changes of charge and discharge required for frequency regulation in a steady state, the proposed algorithm operates BESS within a range of SOC where its life cycle can be maximized. However, during a transient period of which occurrence frequency is low, BESS would be controlled to use its full capacity in a wider range of SOC. In addition, each output of multiple BESS is proportionally determined by its SOC so that the balance in SOC of multiple BESS can be managed. The effectiveness of the proposed control strategy is verified through various case studies employing a test system. Moreover, the control result of BESS with the measured frequency from a real system shows SOC of BESS can be maintained within a specific range although the frequency deviation is biased.