• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제55권8호
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• pp.389-395
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• 2006

In the single-phase switched reluctance motor (SRM) drive, the required DC source is generally supplied by the circuit consisting of bridge rectifier with diodes and many filter capacitances connected with AC source. Although the peak torque ripple of SRM is small because of large capacity of the capacitance, the charge and discharge time swhich the AC source acts on the capacitance are small and the peak current will pass on the side of source, so power factor and system efficiency decrease. Therefore a novel SRM drive system is presented in this paper, which includes drive circuit realizing reduction of torque ripple and improvement of power factor and switching topology. The proposed drive circuit consists of one switching part and diodes which can separate the output of AC/DC rectifier from the large capacitance and supply power to SRM alternately in order to realize reduction of torque ripple and improvement of power factor through the turn on and turn off of switching part. In addition, the validity of method is tested by simulation and experiment.

• 전력전자학회논문지
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• 제6권5호
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• pp.410-415
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• 2001

본 논문에서는 전철시스템의 변전소에서 직류모선에 발생하는 잉여분의 직류전력을 교류전원측으로 회생시킬 수 있는 직류전력 회생시스템의 역률을 개선할 수 있는 새로운 제어기법을 제안하였다. 전력용량과 스위칭 손실을 고려하여 시스템은 3상 구형파 인버터를 기반으로 설계되며 두 개의 인버터, 지그재그 결선된 출력변압기와 교류필터로 구성된다. 회생시스템의 출력전압은 정현파가 아니다. 그러나 기본파 성분을 기반으로 하여 회생되는 복소전력을 해석하므로 고조파에 의해 발생되는 무효전력이 고려되지 않는다. 따라서 비정현파일 때에도 무효전력을 0에 가깝게 제어할 수 있는 새로운 제어기법이 필요하다. 본 논문에서 제안한 제어기법을 검증하기 위하여 컴퓨터 시뮬레이션을 행하였으며, 그 결과 역률이 이론상 99%이상임을 확인하였다.

• Journal of Electrical Engineering and Technology
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• 제5권3호
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• pp.468-476
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• 2010

This paper presents a direct single-stage power converter using single-phase isolated full-bridge converter modules, with inherent power factor correction (PFC) for a 12 kW switched mode power supply (SMPS). The advantages of the proposed converter are its simple control strategy, reduction in number of conversion stage, low input line current harmonics, and improvement in power factor. Analysis of the single-stage converter is carried out in continuous conduction mode of operation. Steady-state analysis of the proposed converter is conducted to obtain converter parameters. A systematic design procedure is also presented for a 12k W converter with a design example. The effect of load variation on SMPS is also studied in order to demonstrate the effectiveness of the proposed converter for the complete range of load conditions. A set of power quality indices on input ac mains for an SMPS fed from a single-stage converter is also presented for easy comparison of their performance.

• 한국태양에너지학회 논문집
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• 제23권3호
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• pp.45-53
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• 2003

This paper presents a study on the power factor improvement of V47- 660 [kW] Wind Turbine Generation System (WTGS) in Jeju wind farm, as a model system in this paper. In this system, the power factor correction is controlled by the conventional method with power condensor banks. Also, this system has only four bank steps, and each one capacitor bank step is cut in every one second when the generator has been cut in. This means that it is difficult to compensate the reactive power exactly according to the variation of them. Actually, model system has very low power factor in the area of low wind speed, which is almost from 4 to 6 [m/s]. This is caused by the power factor correction using power condenser bank. To improve the power factor in the area of low wind speed, we used the static var compensator(SVC) using current controlled PWM power converter using IGBT switching device. Finally, to verify the proposed method, the results of computer simulation using Psim program are presented to support the discussions.

• Journal of Power Electronics
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• 제15권1호
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• pp.227-234
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• 2015

This paper presents the application of bee colony optimization (BCO) to obtain the optimal switching angles for single phase PWM AC choppers. The optimal switching angles are found in the region of 0-${\pi}$ based on the asymmetrical PWM technique. This PWM process results in improvements of the total harmonic distortion of the output voltage and in the input power factor. Simulation and experimental results are compared with the conventional PWM to verify the performance of the proposed PWM process.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2000년도 전력전자학술대회 논문집
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• pp.384-387
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• 2000

In this paper Power factor correction circuit of single-phase three-level boost converter is proposed. The advantage of the proposed control scheme for three-level boost converter are low blocking voltage of each power device low THD(Total Harmonic Distortion) and high power factor. The control scheme is based on the current comparator capacitor compensator and region detector, In simulations the proposed system is validated.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 추계학술대회 논문집
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• pp.214-217
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• 2003

The connectorless power supply system on that multi-contact causes confidence when the wiring reconstructed in the rear. As you see above, contact points between sets and indoor space cause inferior function of audio frequency so it needs to be eliminated. This paper explains the structure of connectorless power supply to supply the system with power crossing the air gap in the part of inductively in the connectorless power supply of both magnetic and electrical model. To get maximum output of electrical load, compensating capacitor compensates to show inter-inductance, lequeage-inductance reducing the track-inductance and access the conditions for resonance. At that time it accesses the maximum electric power. The small change of the value of compensating capacitor causes the changes of maximum electric power. Here the power electronics technology is used not only in the industrial machinery but also in the home appliances so the switching power supply is used to actualize the miniaturization, lightweight, and high efficiency. Generally the condenser input methods are widely used in the rectification circuit of switching power supply, but condenser input method generate great quantity of high frequency components because with this method the current flows in the power input filtering condenser only around value of peak of ac input voltage. To solve these problems, installation of power factor improve circuit on the front of filtering capacitence was considered. Several methods were suggested regarding, but the active filter method which makes smalliging and highly power factor possible are the produce main stream. IC for power factor improvement can be utilized by CMOS process proposing low power consumption. When the high power factor is considered seriously in the power factor improvement circuit, active filter method is selected. In the active filter method, the boost converter is used. Regarding this ·the boost converter is needed.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2004년도 전력전자학술대회 논문집(2)
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• pp.822-825
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• 2004

This paper describes the improvement of performance of power supply for ship's emergency lighting system(SELS). Proposed system is composed of power factor correction (PFC) circuit, emergency power supply system (EPSS), half bridge(HB) inverter, fluorescent lamp(FL) starting circuit and microprocessor control system. Experimental works using proposed system confirm that speedy and stable power to be supplied when main power source cut-off, compared with conventional relay type, and control power factor up to $97.5[\%]$ and input power up to $35.0[\%]$ by adjusting of pulse frequency of the HB inverter.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 전력전자학술대회 논문집
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• pp.552-555
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• 2001

This paper deal with the power factor improvement of DC power regenerating systems, which are composed of two inverters, zig-zag connected output transformers, and an AC filter. The output voltages of the inverter system are not sinusoidal. Regenerated complex power is analyzed on the basis of fundamental components and therefore the reactive power produced by harmonics is not considered. Therefore, it is needed a new control scheme capable of controlling the reactive power nearly to zero for nonsinusoidal case. Computer simulations are carried out to verify the validity of the proposed control scheme.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2005년도 후기학술대회논문집
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• pp.252-253
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• 2005

This paper describes a improvement of power control characteristics of ship's emergency lighting power supply(SELPS), that power factor(PF) is improved and electric power is controlled extensively, and power ON-OFF is controlled and system parameter monitored in remote distance by PC serial communication.