하이브리드 능동전력필터의 전력품질 개선을 위한 Coordinate Transformation 기법에 대한 성능 비교

손진근,박현수,이현재,박훈양 대한전기학회 2022 전기학회논문지 P Vol.71 No.1

In this paper, the performances of Coordinate transformation method for harmonic and reactive power compensation of hybrid active power filters were compared and analyzed. Recently, as the spread of power electronic devices is expanding, the occurrence of harmonics in the system is increasing, and the harmonics have a bad effect on the system and electrical equipment. As a measure against such harmonics, the parallel resonance problem of passive power filters among filters can be solved, and a hybrid active power filter with a small compensation capacity of the active power filter can be considered. However, In order to control the hybrid active power filter to the required power factor, it is necessary to control it through fast tracking even when the load changes. Therefore, in this paper, the performance was analyzed by applying the p-q theory method and the compensation current control method using d-q respectively to the hybrid active power filter. As a result of comparing and analyzing the effects through simulation, it was confirmed that using the p-q theory method quickly followed the target value with a relatively small error even with a variable load than using the d-q method.

능동전력필터의 기준신호발생을 위한개선된 적응예측필터의 성능 분석

배병열,백승택,한병문 전력전자학회 2004 전력전자학회 논문지 Vol.9 No.6

The performance of active power filter depends on the inverter characteristic, the control method, and the accuracy of reference signal generator. The accuracy of reference signal generator is the most critical item to determine the performance of active power filter. This paper introduces a novel reference signal generator composed of improved adaptive predictive filter. The performance of proposed reference signal generator was verified by means of simulation with MATLAB. The application feasibility was evaluated by building and experimenting a single-phase active power filter based on the proposed reference generator, which was implemented in the DSP(digital signal processor) TMS320C31. Both simulation and experimental results confirm that the proposed reference signal generator can be utilized for the active power filter. 능동전력필터의 성능은 인버터의 특성, 제어 방법, 그리고 기준신호발생기의 정확도에 좌우된다. 이중에서 기준신호발생기의 정확도는 능동전력필터의 성능을 결정짓는 가장 중요한 요소이다. 본 논문은 개선된 적응예측필터로 구성한 새로운 기준신호발생기에 대해 소개하고 그 성능을 MATLAB을 이용한 시뮬레이션으로 검증하였다. 그리고 실제 하드웨어의 적용타당성을 평가하기 위해 개선된 기준신호발생기로 구성한 알고리즘을 TMS320C31 DSP(digital signal processor)에 구현하고 이 기준신호발생기를 기반으로 하는 단상능동전력필터의 축소모형을 제작하여 실험을 실시하였다. 시뮬레이션과 실험결과로 제안하는 기준신호발생기가 위상지연이 없는 기준신호를 추출하여 능동전력필터에 활용가능하며 그 성능도 대단히 우수함을 알 수 있었다.

A Steady-state Analysis for an Inverter-based DG to Determine the Optimal Capacity of an Inverter and Harmonic Filters

Kim, Young-Jin,Hwang, Pyeong-Ik,Moon, Seung-Il The Korean Institute of Electrical Engineers 2011 The Journal of International Council on Electrical Vol.1 No.1

Electric power quality in power transmission/distribution systems has deteriorated considerably with the increase in the number and the capacity of inverter-based distributed generators (DGs). This is caused by inverters, connecting DGs to conventional power grids, tend to generate harmonic currents and voltages due to the switching operations of their transistors and diodes. Therefore, this paper presents new methods to adopt harmonic filters to an inverter-based DG, considering a system consisting of both an inverter-based DG and harmonic filters. In order to prove that the system proposed in this paper can be used generally, this paper describes the simulation results obtained by using PSCAD/EMTDC: the relationship between the total harmonic distortion (THD) of the output current and the output power of a DG, and the harmonic mitigation ability of passive and active filters. Furthermore, the system is obliged to satisfy the regulations made by Korea Electric Power Corporation (KEPCO). In the regulations, DG power factor needs to be maintained between 0.9 and 1 in a grid-connected mode. Thus, this paper suggests two methods for the system to control its power factor. First, the power factor should be controlled by the DG inverter rather than an active filter because this brings a dramatic decrease in the capacity of the active filter. Second, the DG should absorb reactive power only in the low output power range in order to prevent a useless increase in the inverter capacity. This method is expected to result in a variable power factor of the system according to its output power. With these control methods, the proposed DG system can successfully operate in a grid-connected mode with an optimally-reduced capacity of active harmonic filters and DG inverters while satisfying the regulations in terms of voltage variation, power factor, and THD.

Three-Phase Hybrid Shunt Filters for Power Quality Improvement

G. Bhuvaneswari,Manjula G.Nair 전력전자학회 2007 JOURNAL OF POWER ELECTRONICS Vol.7 No.3

Active power filters can be cost-effective for use in practical systems with the insertion of a few passive elements in shunt or series configuration. The resulting hybrid filters can be designed to provide dominant lower order harmonic elimination and reactive power support by the passive elements so that the burden on the active filter counterpart is reduced. In this paper, the rate reduction in the shunt active filter is estimated when it is connected in parallel with suitable passive tuned harmonic filters. The active filtering system is based on an appropriate control scheme. The simulation and the experimental results of the shunt active filter, along with the estimated value of reduction in rating, show that the hybrid shunt filtering system is quite effective in compensating for the harmonics and reactive power, in addition to being cost-effective.

고조파 필터 및 인버터의 용량을 고려한 분산전원 시스템의 역률 제어에 관한 연구

김영진(Young-Jin Kim),황평익(Pyeong-Ik Hwang),문승일(Seung-Il Moon) 대한전기학회 2009 전기학회논문지 Vol.58 No.11

Electric power quality in power transmission/distribution systems has considerably been deteriorated with the increase in the capacity of distributed generators (DGs). It is because inverters, connecting DGs to conventional power grids, tend to generate harmonic current and voltage. For harmonic mitigation, a large amount of research has been done on passive and active filters, which have been operating successfully in many countries. This paper, therefore, presents how to adopt the filters to an inverter-based DG, with considering a system consisting of both inverter-based DG and harmonic filters. In particular, this paper describes the simulation results using the PSCAD/EMTDC: firstly, the relationship between total harmonic distortion(THD) of current and output power of DG: secondly, the harmonic mitigation ability of passive and active filters. The system, furthermore, is obliged to satisfy the regulations made by Korean Electric Power Corporation(KEPCO). In the regulations, power factor should be maintained between 0.9 and 1 in a grid-connected mode. Thus, this paper suggests two methods for the system to control its power factor. First, the inverter of DG should control power factor rather than an active filter because it brings dramatic decrease in the capacity of the active filter. Second, DG should absorb reactive power only in the range of low output power in order to prevent useless capacity increase of the inverter. This method is expected to result in the variable power factor of the system according to its output power.

Modelling and Analysis of Controller for Three-Phase Shunt Active Power Filter

Dr. RAMA RAO P.V.V.,P.DEVIKIRAN,M. D. L. SARANYA 보안공학연구지원센터 2016 International Journal of Signal Processing, Image Vol.9 No.1

Now a days, because of enhancement in high speed computing elements, high voltage controlled semi-conductor devices and emergence of new power circuit topologies, the Voltage Source Converter (VSC) based Active Power Filter (APF) is finding applications for compensating harmonic currents drawn by the various loads. As the active filter consists of semi-conductor devices alone, the response time of this device is very fast and it doesn’t suffer from resonance and other stability problems as faced by the normal passive filters. The Active filters are generally used at harmonic producing loads. Among all APF’s the Shunt Active Power Filter (SAPF) is more prominent at medium/high voltage applications, and also it provides higher efficiency. SAPF in the power circuit can be used either by using the voltage-sourced PWM converter equipped with a DC capacitor or a current-sourced PWM converter equipped with a DC inductor. This paper presents an approach to determine reference compensation currents of the three-phase SAPF under distorted and/or unbalanced source voltages in steady state. It is planned to design a Synchronous Reference Frame (SRF) controller for Voltage Source Converter (VSC) based Shunt active power filter for harmonic compensation. The simulation results have been obtained by using MATLAB/ SIMULINK.

직ㆍ병렬 능동 전력필터 시스템을 이용한 불평형 전원전압 보상

姜旻衡(Min-Hyung Kang),金榮石(Young-Seok Kim) 대한전기학회 2007 전기학회논문지 Vol.56 No.4

This paper suggests of a 3-phase 3-wire unified active power filter. The system is composed of a series active power filter and a parallel active power filter. The proposed series active power filter compensating unbalance source voltage and current harmonics of the parallel active power filter improves power factor. The proposed algorithm which improves for power factor and harmonic reduction are calculated by the performance function, and which compensates for the unbalanced source voltage is calculated based on the symmetrical component analysis. We composed a combined system of the series active power filter and parallel active power filter to confirm a validity of the proposed control methods. The effectiveness of the proposed algorithm is confirmed by the experiments.

복합형 전력필터 설계에 관한 연구

송의호 國立 昌原大學校 産業技術硏究所 2002 産技硏論文集 Vol.16 No.-

A new hybrid power filter using variable capacitor banks is presented to overcome the high cost problem of the active or the other hybrid active filters. The proposed hybrid active filter which consists of tuned(5th and 7th harmonics) LC passive filters, power factor improvement(PFI) capacitor bank, and active filter compensates power factor as well as harmonic currents. Since most of harmonic currents are filtered by the passive filter and most of reactive power is compensated by the PFI capacitor bank, the power rating of active filter can be minimized, resulting in cost minimization of the proposed hybrid active filter. A 400kVA hybrid active filter system is implemented and tested using 1MVA thyristor rectfier load to verify the operation and performance.

Active Damping for Wind Power Systems with LCL Filters Using a DFT

Lee, June-Seok,Jeong, Hae-Gwang,Lee, Kyo-Beum The Korean Institute of Power Electronics 2012 JOURNAL OF POWER ELECTRONICS Vol.12 No.2

This paper proposes a simple active damping algorithm for small-scale wind power systems with an LCL filter. Compared to an L filter or an LC filter, an LCL filter can decrease the harmonics induced by low switching frequencies and produce a satisfactory grid-side current using a comparatively low inductance. Additional active damping of the filter resonance is necessary when an LCL filter is used. This paper introduces an active damping method using a Discrete Fourier Transform (DFT) filter to improve performance without additional sensors or complexity. Experimental results are shown to verify the validity of the proposed algorithm as an active damping method.

Active Damping Method Using Grid-Side Current Feedback for Active Power Filters with LCL Filters

Tang, Shiying,Peng, Li,Kang, Yong The Korean Institute of Power Electronics 2011 JOURNAL OF POWER ELECTRONICS Vol.11 No.3

LCL filters installed at converter outputs offer a higher harmonic attenuation than L filters. However, as a three order resonant circuit, it is difficult to stabilize and has a risk of oscillating with the power grid. Therefore, careful design is required to damp LCL resonance. Compared to a passive damping method, an active damping method is a more attractive solution for this problem, since it avoids extra power losses. In this paper, the damping capabilities of capacitor current, capacitor voltage, and grid-side current feedback methods, are analyzed under the discrete-time state-space model. Theoretical analysis shows that the grid-side current feedback method is more suitable for use in active power filters, because it can damp LCL resonance more effectively than the other two methods when the ratio of the resonance and the control frequency is between 0.225 and 0.325. Furthermore, since there is no need for extra sensors for additional states measurements, this method provides a cost-efficient solution. To support the theoretical analysis, the proposed method is tested on a 7-kVA single-phase shunt active power filter.