• 전기학회논문지P
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• 제56권3호
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• pp.136-141
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• 2007

In this paper, a new simple control method for active power filter which can realized the complete compensation of the harmonic currents is proposed. In the proposed scheme, a compensating current reference generator employing resonance model implemented by a DSP(Digital Signal Processor) is introduced. Deadbeat control is employed to control the active power filter. The switching pulse width based SVM(Space Vector Modulation) is adopted so that the current of active power filter is been exactly equal to its reference at the next sampling instant. To compensate the computation delay of digital controller, the prediction of current is achieved by the current observer with deadbeat response.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2000년도 춘계학술대회논문집 - 한국공작기계학회
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• pp.385-390
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• 2000

This paper deals with the design and simulation of the hybrid power filter to compensate reactive power and harmonic components of nonlinear load. Control target is a 3-phase diode full bridge rectifier with L-R-C nonlinear load, this load is assumed adjustable speed driver(ASD). The hybrid filter consists of a shunt active filter, shunt passive filters and series inductors. Control algorithm is based on instantaneous power compensation theory proposed by H.Akagi and etc. The result from simulation shows the hybrid filter is superior than other filters on the point of compensation performance and low cost. The PSCAD/EMTDC 3.0 is used as simulation tools.

• 전력전자학회논문지
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• 제6권5호
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• pp.386-393
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• 2001

본 논문에서는 3상 3선식 전력시스템에서 전류 고조파와 전원 전압 불평형을 보상하는 직렬형 능동전력필터에 관하여 연구하였다. 직렬형 능동전력필터는 병렬형 수동필터와 병용으로 구성되어져 수동필터의 고조파 보상 능력을 향상시켜주며, 전원측의 전류 고조파를 더욱 저감시키고, 전원 전압의 불평형을 보상하여 부하측에 평형한 전원조건이 형성되도록 보상해 준다. 제안하는 제어 알고리즘은 전류 고조파 보상을 위한 방법과 전원 전압 불평형을 보상하는 방법으로 나누어지며 최종적인 보상 전압은 계산되어진 두 가지 보상 전압의 합의 형태가 되겠다. 전류 고조파 보상을 위한 보상 지령 전압은 정의되어진 성능함수에 의해 계산되어지며, 전원 전압 불평형 보상을 위한 보상 지령 전압은 동기 좌표를 이용하여 계산되어진다. 실험을 통하여 제안하는 알고리즘의 우수성을 입증하였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 춘계학술대회 논문집
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• pp.1334-1339
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• 2004

This paper proposes transformerless power conversion system consisting of a single-phase diode rectifier and a shunt hybrid filter for the electric-railway system. The hybrid filter consists of a single tuned LC filter per a phase and a low-rated NPC type multi-level inverter. Compared with conventional active filters. Transformers are not used. Also, LC filter works as not only a harmonic filter tuned at the 5th harmonic frequency but also a switching-ripple filter. The rating of the active filter can be decreased by using a NPC type multi-level inverter. The simulation results confirm the validity of the system.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 춘계학술대회 논문집
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• pp.1427-1432
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• 2004

This paper proposes transformerless power conversion system consisting of a single-phase diode rectifier and a shunt hybrid filter for the electric-railway system. The hybrid filter consists of a single tuned LC filter per a phase and a low-rated NPC type multi-level inverter. Compared with conventional active filters. Transformers are not used. Also, LC filter works as not only a harmonic filter tuned at the 5th harmonic frequency but also a switching-ripple filter. The rating of the active filter can be decreased by using a NPC type multi-level inverter. The simulation results confirm the validity of the system

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.174-178
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• 2005

This paper presents a novel fuzzy logic based control method for shunt active filters. Since the fuzzy sets are based on linguistic description, therefore they don't need to the mathematical model of the investigated systems. The proposed method is very suitable to nonlinear and time variant loads. The controller is robust, reliable and it has a smooth response. Also transient response of method is much better than the other classical methods. The simulation results confirm the suitable performance of the filter using this control method.

• Journal of Power Electronics
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• 제16권5호
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• pp.1964-1980
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• 2016

This paper presents a new simplified harmonics extraction algorithm based on the synchronous reference frame (SRF) for an indirect current controlled (ICC) three-level neutral point diode clamped (NPC) inverter-based shunt active power filter (SAPF). The shunt APF is widely accepted as one of the most effective current harmonics mitigation tools due to its superior adaptability in dynamic state conditions. In its controller, the SRF algorithm which is derived based on the direct-quadrature (DQ) theory has played a significant role as a harmonics extraction algorithm due to its simple implementation features. However, it suffers from significant delays due to its dependency on a numerical filter and unnecessary computation workloads. Moreover, the algorithm is mostly implemented for the direct current controlled (DCC) based SAPF which operates based on a non-sinusoidal reference current. This degrades the mitigation performances since the DCC based operation does not possess exact information on the actual source current which suffers from switching ripples problems. Therefore, three major improvements are introduced which include the development of a mathematical based fundamental component identifier to replace the numerical filter, the removal of redundant features, and the generation of a sinusoidal reference current. The proposed algorithm is developed and evaluated in MATLAB / Simulink. A laboratory prototype utilizing a TMS320F28335 digital signal processor (DSP) is also implemented to validate effectiveness of the proposed algorithm. Both simulation and experimental results are presented. They show significant improvements in terms of total harmonic distortion (THD) and dynamic response when compared to a conventional SRF algorithm.

• Journal of Electrical Engineering and Technology
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• 제11권2호
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• pp.405-415
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• 2016

This paper presents a model predictive control for shunt active power filters in synchronous reference frame using space vector pulse-width modulation (SVPWM). The three phase load currents are transformed into synchronous rotating reference frame in order to reduce the order of the control system. The proposed current controller calculates reference current command for harmonic current components in synchronous frame. The fundamental load current components are transformed into dc components revealing only the harmonics. The predictive current controller will add robustness and fast compensation to generate commands to the SVPWM which minimizes switching frequency while maintaining fast harmonic compensation. By using the model predictive control, the optimal switching state to be applied to the next sampling time is selected. The filter current contains only the harmonic components, which are the reference compensating currents. In this method the supply current will be equal to the fundamental component of load current and a part of the current at fundamental frequency for losses of the inverter. Mathematical analysis and the feasibility of the suggested approach are verified through simulation results under steady state and transient conditions for non-linear load. The effectiveness of the proposed controller is confirmed through experimental validation.

• Journal of Power Electronics
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• 제11권6호
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• pp.914-921
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• 2011

Commencing with incandescent light bulbs, every load today creates harmonics. Unfortunately, these loads vary with respect to their amount of harmonic content and their response to problems caused by harmonics. The prevalent difficulties with harmonics are voltage and current waveform distortions. In addition, Electronic equipment like computers, battery chargers, electronic ballasts, variable frequency drives, and switching mode power supplies generate perilous amounts of harmonics. Issues related to harmonics are of a greater concern to engineers and building designers because they do more than just distort voltage waveforms, they can overheat the building wiring, cause nuisance tripping, overheat transformer units, and cause random end-user equipment failures. Thus power quality is becoming more and more serious with each passing day. As a result, active power filters (APFs) have gained a lot of attention due to their excellent harmonic compensation. However, the performance of the active filters seems to have contradictions with different control techniques. The main objective of this paper is to analyze shunt active filters with fuzzy and pi controllers. To carry out this analysis, active and reactive current methods ($i_d-i_q$) are considered. Extensive simulations were carried out. The simulations were performed under balance, unbalanced and non sinusoidal conditions. The results validate the dynamic behavior of fuzzy logic controllers over PI controllers.

• Journal of Power Electronics
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• 제13권1호
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• pp.161-169
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• 2013

This paper proposes a novel control strategy for a unified power quality conditioner (UPQC) including a series and a shunt active power filter (APF) to compensate the harmonics in both the distorted supply voltage and the nonlinear load current. In the series APF control scheme, a proportional-integral (PI) controller and a resonant controller tuned at six multiples of the fundamental frequency of the network ($6{\omega}_s$) are performed to compensate the harmonics in the distorted source. Meanwhile, a PI controller and three resonant controllers tuned at $6n{\omega}_s$(n=1, 2, 3) are designed in the shunt APF control scheme to mitigate the harmonic currents produced by nonlinear loads. The performance of the proposed UPQC is significantly improved when compared to that of the conventional control strategy thanks to the effective design of the resonant controllers. The feasibility of the proposed UPQC control scheme is validated through simulation and experimental results.