• Proceedings of the KIPE Conference
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• 2004.07b
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• pp.524-527
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• 2004

When the electric tractions are stopped or driven through the falling slope way, it occured to surplus energy in the DC power line. At present, these energy are exhausted by breaking-system. The converter is not only capable of feeding energy back into the AC source during excessive regeneration. It is issued for this surplus energy regenerating system. These systems are faced with high voltage and high power for railway DC power regeneration. This paper proposed a parallel PWM converter how to solve these problem.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.125-127
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• 2005

In this paper, the control algorithm of DC source device for inverter starting is proposed and the control method for compensating unbalance system source on operating time in the voltage type PWM converter with driving and regenerative faculty is suggested. The maintaining way of balancing condition for converter of AC source is used the compensating unbalanced status by current control loop. Because it is possible that the unbalanced System control is used to leakage transformer not equaled reactance by each phase in rectifier system, the proposed H/W and control algorithm of rectifier system is contributed to minimize of device and rising efficiency.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.524-528
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• 1998

The voltage-source inverters are normally equipped with an electrolytic capacitor in their DC link, however, the electrolytic capacitor has several disadvantages such as increasing size, limiting converter life and reliability. Therefore, several approaches for removing the DC link capacitor have been studied by the authors. This paper proposes a new voltage-source inverter without DC link components. To reduce waveform distortion of the AC source current, the current-controlled PWM-rectifier with di/dt feedback is introduced. The di/dt feedback gain and LC parameters are investigated by calculation for a 0.75kW induction motor driven by this inverter. The calculated AC source currents maintain nearly sinusoidal waveforms with a unity power factor.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.551-554
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• 2002

This paper describes a new interactive inverter between a photovoltaic(PV) array and single-phase utility that avoid the bulky input (60Hz) transformer on the AC side. The interface employs a pwm boost converter on the DC side followed by a pwm current-forced single-phase rectifier for injecting the power from the PV array into the mains. The current waveform at the AC side remains sinusoidal and exactly in phase at all time. The circuit also has the advantage of requiring fewer switching device than high-frequency link system. This paper describes modeling of PV array and new system topology. Simulation results on the performance of the connection are also presented.

• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.14-15
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• 2013

본 논문에서는 컨버터의 병렬운전을 하는데 있어 제안한 드룹제어를 사용하여 전력을 분담한다. 제안한 방법을 이용하면 직류배전에서 병렬시스템의 용량증설을 용이하게 할 수 있다. 기존의 교류전원에서 사용하는 드룹 제어 방법을 새롭게 개선하여 직류전원에서 드룹 제어가 적용되도록 드룹 제어기를 설계한다. 그리고 제안한 드룹 제어기의 제어방법을 상세히 설명한다. 본 논문에서는 제안한 제어방법을 50[kW] 직류배전 시스템에 적용하여 시뮬레이션을 통하여 제안된 기법의 타당성을 검증한다.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.10
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• pp.618-624
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• 2004

In this paper, a new controller for a single-phase PWM converter is described, which requires only two input parameters, the dc voltage and the ac current. Detail simulation model with EMTDC(Electro-Magnetic Transient program for DC transmission) including power circuit and controller was developed to verify the operation of proposed controller. The application feasibility of the proposed controller was verified through experimental works with a prototype. The proposed controller has a simple structure in the point of hardware implementation, and shows excellent performance in normal operation as well as in sudden load change.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.426-428
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• 1997

This paper presents the linearized optimal PWM techniques for current source GTO converter. This proposed method is to linearize an optimal PWM modulation strategy so that the turn-on/off-periods of the GTO switches can be computed on-line in real-time for any modulation index. This allows the rapid and continuous regulation of the DC output current while producing the sinusoidal AC input current waveform and unit power factor.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.243-245
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• 1994

A PWM forced-commutated converter with DC voltage source is studied in this paper. This PWM-VSC using spacs vector modulation permits to control bi-directional power exchange between the AC mains and the DC source. The principle of the active and reactive power control is presented. In transient operation, the analysis of reactive component current is performed. Finally, the simulation results are also presented and discussed.

• The Transactions of the Korean Institute of Power Electronics
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• v.21 no.5
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• pp.427-433
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• 2016

This paper proposes a new method for the current ripple reduction of a three-phase interleaved bidirectional DC-DC converter. Usually, the three-phase interleaved bidirectional DC-DC converter is used for battery charging and discharging to reduce battery current ripple. In V2G application, a PWM AC-DC converter is used to connect the AC power grid and three-phase interleaved bidirectional DC-DC converter for battery charging and discharging. The magnitude of DC link voltage affects the battery current ripple magnitude. Therefore, the magnitude of the battery ripple current is analyzed with variations of battery and DC link voltages. The ripple current magnitude is found to be minimized by controlling the DC link voltage. Simulation and experimental results show the usefulness of the proposed method.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.1
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• pp.87-94
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• 2008

A method for improving current THD of Valley-fill rectifier is proposed in this paper. The proposed topology combines a boosting inductor with Valley-fill rectifier which carry out AC/DC conversion and PFC simultaneously The boosting effect by PWM switching makes low THD current and improve of Valley-fill rectifier. The operation modes and THD of input current are analyzed as applied the boosting inductor, and the optimum value of boosting inductor is determined A 100[W] single-stage converter has been designed and tested. Experimental results are resented to verify the validity of the proposed method.