• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 A
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• pp.348-350
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• 1994

In this paper, bi-directional buck-boost DC-DC converter for bus regulation system is presented. This converter which has one buck and one boost topology achieves bi-directional power flow using a common power inductor and alternative power switches. By connecting the battery to bus line, it can be regulated to bus voltage and charged the battery alternatively. And as an application, a mode controller is adopted to the converter.

• 전기학회논문지P
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• 제58권4호
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• pp.404-409
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• 2009

A DC power system has many loads with various functions. In particular, these sizable loads take the form of power electronic converters. When they are tightly regulated, the loads appear as constant power loads and result in negative incremental input impedance. Under certain conditions the effect of such loads on the power system is causes instability. In this paper, converter with a large storage capacitor and a lag compensator is proposed as a DC bus conditioner to mitigate the voltage transients on the bus. In addition, the proposed control approach has the advantage of performing both the functions of mitigating the voltage bus transients and maintaining the level of energy stored. Simulation and experimental results showed that the proposed control method was operated well in a small-scale DC power system that contained subsystems with constant power characteristics, such as DC/DC converters and electrical drives.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.2348-2356
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• 2011

In recent years, many researches for DC power distributed system (PDS) are being preformed and the importance of the DC PDS is more and more emphasized. Furthermore, in the railway system, the DC PDS is used in subway station lighting, facilities, etc. In the DC PDS, DC bus voltage instability may be occurred by the operation of multiple parallel loads such as pulsed power load, motor drive system, and constant power loads. Thus, good quality and high reliability for electric power are required and voltage bus conditioner (VBC) may be used the DC PDS. The VBC is a DC/DC converter for mitigation of the bus transients. In this paper, adaptive controller is designed. The simulation results by PSIM are presented for validating the proposed control algorithm.

• 전기학회논문지
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• 제61권11호
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• pp.1617-1624
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• 2012

A DC power system has many loads with varied functions. Also, there may be large pulsed loads with short duty ratios which can affect the normal operation of other loads. In this paper, Voltage Bus Conditioner(VBC) without any current sensors is proposed to damp the bus voltage transients by parallel pulsed loads. The proposed control approach requires only one voltage sensor and carries out both the functions of damping the bus voltage transients and maintaining the level of energy stored. The proposed control technique has been implemented on a TMS320F2812 Digital Signal Processor(DSP). Simulated results by a Matlab Simulink and experimental results are presented which verify the control principles and demonstrate the practicalty of the approach.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.1234-1235
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• 2011

A DC Power Distribution Systems(DC PDS) are widely used in telecommunication system, electric vehicle, aircraft, military system, etc. In the DC PDS, DC bus voltage instability may be occurred by the operation of multiple loads such as pulsed power load, motor drive system, and constant power loads. To damp the transients of the DC bus voltage, the Voltage Bus Conditioner(VBC) with the PI compensator is used. In this paper, the validity of the proposed VBC system is verified by PSIM simulation package.

• 한국전자파학회논문지
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• 제17권2호
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• pp.148-151
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• 2006

PCB에서의 전자파 간섭원으로 DC power-bus의 공진이 자주 지목된다. 이것은 결국, 전도성 또는 전파 방사의 형태로, 하나 또는 인접한 시스템에서 디지털 SI를 저하시키게 된다. 따라서 PCB의 방사 문제를 파악하는 것은 중요하므로, 본 논문은 DC power-bus 공진 모드에 대한 방사를 면밀히 살펴본다. 엄밀한 주파수 영역 해석법을 이용하여 임피던스와 방사 전계를 구하고, 이는 물리와 전자파 해석 모의시험에 의해 타당성이 검토된다.

• 전력전자학회논문지
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• 제26권4호
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• pp.263-270
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• 2021

Active AC/DC converters with PWM operation are utilized to regulate rectified DC bus voltage of a permanent magnet synchronous generator in the maritime DC power system. A DC bus voltage regulation strategy that exploits the six-step operation is proposed in this study. Compared with that of the PWM operation, switching loss of the converter can be significantly reduced under the six-step operation. Moreover, conduction loss can also be reduced due to the high modulation index and reduced flux-weakening current of the six-step operation. A controller is used for the proposed DC bus voltage regulation strategy to verify its validity with the simulation and experimental setup. The simulation and the experimental test results showed that the converter loss reduces to a maximum of 70% and 19%, respectively.

• 전기학회논문지P
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• 제59권4호
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• pp.372-376
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• 2010

Electrolytic capacitors have been widely used in power electronics system because of the features of large capacitance, small size, high-voltage, and low-cost. Electrolytic capacitors, which is most of the time affected by aging effect, plays a very important role for the power electronics system quality and reliability. Therefore it is important to estimate the parameter of an electrolytic capacitor to predict the failure. The estimation of the equivalent series resistance(ESR) is important parameter in life condition monitoring of electrolytic capacitor. This paper proposes a simple technique to measure the ESR of an electrolytic capacitor. This method uses a switching DC/DC boost converter to measure the DC Bus capacitor ESR of power converter. Main advantage of the proposed method is very simple in technique, consumes very little time and requires only simple instruments. Simulation results are shown to verify the performance of the proposed method.

• Journal of Power Electronics
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• 제12권4호
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• pp.567-577
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• 2012

This paper introduces a new scheme to balance the DC bus voltages of a cascaded H-bridge converter which is used as a Distribution Static Synchronous Series Compensator (D-SSSC) in electrical distribution network. The aim of D-SSSC is to control the power flow between two feeders from different substations. As a result of different cell losses and capacitors tolerance the cells DC bus voltage can deviate from their reference values. In the proposed scheme, by individually modifying the reference PWM signal for each cell, an effective balancing procedure is derived. The new balancing procedure needs only the line current sign and is independent of the main control strategy, which controls the total DC bus voltages of cascaded H-bridge. The effect of modulation index variation on the capacitor voltage is analytically derived for the proposed strategy. The proposed method takes advantages of phase shift carrier based modulation and can be applied for a cascaded H-bridge with any number of cells. Also the system is immune to loss of one cell and the presented procedure can keep balancing between the remaining cells. Simulation studies and experimental results validate the effectiveness of the proposed method in the balancing of DC bus voltages.

• Journal of international Conference on Electrical Machines and Systems
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• 제1권3호
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• pp.391-396
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• 2012

The Voltage Bus Conditioner(VBC) is a bidirectional DC-DC converter for damping the instability and any transients of the bus voltage in a DC Distributed Power System(DPS). In this paper, a PI controller for the VBC has been designed for the frequency domain. The proposed PI controller not only dampens the bus transients, but also keeps the storage voltage level. Simulation by Matlab/Simulink and experimental results are presented for the validity of the proposed control technique.