• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.603-606
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• 2002

This paper introduces a control algorithm for 3-phase 4-wire series active power filter This control algorithm compensates harmonics and neutral line currents which are generated by balanced or unbalanced nonlinear loads. The advantage of this control algorithm is direct extraction of compensation voltage references. Therefor calculation time is shorten and the performance of series active power filter is improved. Compensation principle of the proposed control algorithm is presented in detail. Experimental results are shown to verify the effectiveness of tile proposed control algorithm.

• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.224-225
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• 2013

This paper describes the four switch three-phase Z-source active power filter. This novel configuration has many advantages like reduction of cost, switching loss and smaller drive circuit. The paper presents an application of direct current control(DCC) method in a three-phase parallel Z-source active power filter to reduce the harmonics generated by the nonlinear load. The compensation principles and dynamics of the system are discussed in detail. The results show that the proposed control strategy is feasible and efficient.

• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.479-480
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• 2013

기존의 태양광 시스템은 일사량이 존재할 경우 즉 태양이 있을경우에만 동작하는 낮은 활용도를 가진다. 본 논문에서는 태양광에서 발전되는 불규칙적인 에너지를 효과적으로 사용하기 위해 BESS 시스템을 결합하여 태양광 시스템의 활용도를 높이며, 계통의 전원의 안정화를 위하여 Active Power Filter기능을 수행한다. 논문에서는 이를 구현하고 타당성을 검증하였다.

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.534-535
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• 2014

This paper proposes parallel operation of multi function rapid-charger with an active power filter. Rapid-charger can be installed in public institutions or mart parking lot. But conventional charger has disadvantage that it can not be used as the active power filter in charging mode with only one charger. So using 3-parallel operation, effective mode transfer between battery charging and APF function can obtain effect of harmonic compensation and improving the utilization of the charger.

• Proceedings of the KIEE Conference
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• 2004.04a
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• pp.103-105
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• 2004

In this paper, a novel control scheme compensating for source voltage unbalance and current harmonics and power factor simultaneously in unified active power filter systems combined with shunt passive filters is proposed, where no low/high-pass filter are used in deriving the reference voltage for compensation. Using digital all-pass filters, the phase angle and the reference voltages compensating for harmonic current and unbalanced voltage are derived from the positive sequence component of the unbalanced voltage. The amplitude of d-axis current in a series filter is controlled as zero for power factor correction. The validity of the proposed control scheme has been verified by experimental results.

• Proceedings of the KIPE Conference
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• 2015.07a
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• pp.447-448
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• 2015

지연 등화기(Delay Equalizer) 또는 위상 필터(Phase Filter)라고도 불리는 전역 통과 필터(All Pass Filter)는 주파수의 변화와 관계없이 위상만을 변화 시키는 시간 지연 장치(Time Delay Device)이다. 모든 주파수에서 진폭의 이득이 '0' 또는 일정하지만, 위상의 특성만을 개선하기 위해 사용되는 위상 필터 이다. 본 논문은 이와 같은 전역 통과 필터(APF)의 특성을 이용하여 순시 유효 전력(Active Power) 및 순시 무효 전력(Reactive Power)의 측정 방법에 대하여 연구하였다. 전역 통과 필터(APF)의 좌표변환을 사용하여, 필터에서의 정보를 통한 유효 전력과 무효 전력 측정이 가능하다. 따라서 본 논문에서는 시뮬레이션을 통해 그 타당성을 검증하였다.

• Journal of Power Electronics
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• v.17 no.6
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• pp.1637-1649
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• 2017

This paper describes an intensive analysis of a harmonic identification algorithm in non-ideal voltages source systems. The dq-axis Fourier with a positive sequence voltage detector (DQFP) is a novel harmonic identification algorithm for active power filters. A compensating current control system based on repetitive control is presented. A design and stability analysis of the proposed current control are also given. The aim of the paper is to achieve a robustness of the harmonic identification in a distorted and unbalanced voltage source. The proposed ideas are supported by a hardware in the loop technique based on a $eZdsp^{TM}$ F28335 and the Simulink program. The obtained results are presented to demonstrate the performance of the harmonic identification and the control strategy for the active power filter in non-ideal systems.

• Journal of Electrical Engineering and Technology
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• v.12 no.1
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• pp.151-160
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• 2017

This paper presents a new technique of reference current generator based on Kalman filter (KF) estimator for three-phase shunt active power filter (APF). The stationary reference frame (d-q algorithm) is used to transform the load currents into DC component. The harmonics of load currents are extracted and the three-phase reference currents are generated using KF estimator. The work is simulated using Matlab/Simulink platform. To validate the simulation results, an experimental test-rig have been perform using real-time control dSPACE DS1104. In addition, hysteresis current control was used to generate the switching signal for the correction of the harmonics in the system. The non-linear load were constructed with three-phase rectifier which connected in series with inductor and parallel with resistor and capacitor. The results shows that the new technique of shunt APF embedded with KF is proven to eliminate the harmonics created by the non-linear load with some improvement on the total harmonics distortion (THD).

• The Transactions of the Korean Institute of Power Electronics
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• v.18 no.1
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• pp.10-17
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• 2013

In this paper, a new active damping method of LCL filter without capacitor voltage sensors is proposed for 3 phase PWM Inverter. Normally, L filter or LCL filter is used as an output filter of grid connected PWM inverter. An LCL filter has more excellent performance than L filter to reduce harmonic current, so the small inductance value can be used. However, the resonance problem in LCL filter is happen due to the zero impedance by the addition of LC branch. To solve the resonance problem, the various active damping method has been proposed so far. Generally, the virtual resistor active damping methods is required to additional hardware sensors for measurement of capacitor voltage and current. In this paper, the new active damping method is proposed without any capacitor voltage or current sensors. In the proposed method, the resonance component of the capacitor voltage of LCL filter can be observed by a simple MRAS(Model Reference Adaptive System) observer without additional hardware sensors, and this component is suppressed by feedforward compensation. The validity of the proposed method is proven by simulation and experiment on the 3-phase PWM inverter system.

• The Transactions of the Korean Institute of Power Electronics
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• v.7 no.2
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• pp.178-185
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• 2002

This paper describes the implementation of three-phase three-wire active power filter system with a instantaneous PSD for distorted and unbalanced power conditions. The positive sequence voltage of the distorted and the unbalanced power system is calculated by the Instantaneous PSD, and phase transformation matrix of the instantaneous power theory is achieved with detected positive sequence voltage. Finally, the proposed method is experimented and tested under unbalanced nonlinear load as well as unbalanced /distorted condition in power system.