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EPE 1999 - Topic 09d: Active Filters and Harmonics
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1999 - Conference > EPE 1999 - Topic 09: POWER ELECTRONICS IN GENERATION, TRANSMISSION AND DISTRIBUTION > EPE 1999 - Topic 09d: Active Filters and Harmonics
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	A Comparative Study between Two Structures of Hybrid Active Filter for Harmonic Compensation of a 18-Thyristors Cycloconverter Fed Induction Motor Drive   By S.H. Shahalami; L. Benchaita; S. Saadate	[View]   [Download]
Abstract: Cycloconverter fed induction motor drives generates an important integer harmonics together with a broad spectrum consisting of inter-harmonics and sub-harmonics which can be varied by adjustable speed of induction motor (ASD). With regard to the circuit topology, there are three basic kinds of shunt filter, voltage source (VSAF) and current source (CSAF) active filter and passive filter. Use of passive shunt filters alone have some important drawbacks on power distribution system which supply nonlinear loads producing a wide range of harmonic current frequency. Parallel and series resonance with impedance of power system are the phenomenas which distort the voltage of the point of common coupling (PCC). These disadvantages can be reduced by the combined use of the active and passive filters. Compensation of varying current frequency together with a good damping of parallel and series resonance harmonic frequency by active filter and the fixed current frequencies by passive filters can be achieved by an appropriate coordinating their operations. This paper presents a comparison of two hybrid topologies, for compensation of current harmonics produced by a 18-thyristors ot three pulse cycloconverter fed induction motor, from different points of view, such as power circuit design, filtering quality.
	A Multiple Rotating Integrator Controller for Active Filters   By M. Bojrup; P. Karlsson; M. Alaküla; L. Gertmar	[View]   [Download]
Abstract: A controller scheme based on multiple rotating integrators (MRI) for an active filter is presented, analysed and evaluated. The inherent performance of integrators in the synchronous reference dqframe for reduction of steady state errors are used in multiple rotating reference frames in order to compensate harmonics to obtain a steady state error equal to zero. Both measurements and simulations clearly verify the advantageous performance in comparison to presently used active filters. Particularly in experimental verification, the MRI controller structure outperforms the alternative methods due to its low sensitivity to parameter variation and non-linear properties of the system. This is particularly important since the superiority of the MRI structure is not fully revealed only by simulation. It is shown that the MRI structure do suppress the harmonics to the measurement noise level.
	A New Efficient Filtering System   By D. Alexa; F. ionescu; A. Sirbu; A. Lazar; L. Gitlan	[View]   [Download]
Abstract: A new filtering system consisting of passive filters with capacitors connected in parallel with the diodes and a small-rated inverter in introduced. The small-rated inverter starts to work when disturbances occur in the three-phase network, sending back to the network the excess energy taken by all the capacitors from the network during these disturbances. The proposed filtering system has reduced size and costs as well as high efficiency. Simulation experiments proving the effectiveness of the solution are also presented.
	A New Method of the Instantaneous Reactive Power Determination for Single-Phase Power Electronic Systems   By B. Dobrucky; M. Pokorny; V. Racek; R. Havrila	[View]   [Download]
Abstract: The paper deals with the new method of analysis of single-phase power electronic systems. Using a new particular transform theory the ordinary single-phase system can be transformed into equivalent two-axes orthogonal one. The new original thought is based on the idea that ordinary single-phase quantity can be complemented by fictitious second phase so that both of them will create orthogonal and ortho-normal system, as is usual in three-phase systems. Application of above theory makes it possible to use complex methods of analysis as instantaneous reactive power method, which have not been usable for single-phase systems so far. Both, the active and reactive powers can be determined by this way. Practical application of the method is outlined for the case of reference current determination for single-phase power active filter. Three different ways of reference current determination are introduced with very similar results. The paper also shows some examples of the simulation verification results, which proved a high accuracy and extremely fast response of the single-phase active filter with control, based on the introduced method.
	A Sliding Mode Control Design of an Active Power Filter With a Low-Pass Filter as Input Stage   By O. Lopez Lapena; L. Garcia de Vicuña; J. Matas; M. López; M. Castilla	[View]   [Download]
Abstract: Single-phase active filter and its sliding mode control design are presented. The proposed scheme consists of a conventional voltage-source inverter, in which a low-pass filter has been added as input stage. Consequently, the current ripple is reduced from the conventional structure, but an accurate controller design technique is needed to avoid the self-oscillation of the input filter. This paper demonstrates that a sliding mode control can be obtained, which permits the compensation of the harmonic distortion and phase displacement of the line current, by imposing a desired dynamic behavior on the system.
	A Universal Symmetrical Topologies for Active Power Line Conditioners   By R. Strzelecki; J. Kukluk; H. Supronowicz; H. Tunia	[View]   [Download]
Abstract: There have been the new universal configurations of Active Power Line Conditioners (APLC) proposed. In the simplest case, they are combinations of two base APLC systems connected symmetrically in a cascade with one common add-on source. The basic one-phase symmetrical APLC and example of possible applications are shown in the paper. Power flow between add-on sources of the two basic APLC and their energetic properties are compared to indicate that the new proosed solution allow to minimize losses and are superior to the base APLC.
	Active Filters: Control with Harmonic Rotating Frames of Reference   By D. Butt; M. Sumner; J. Clare	[View]   [Download]
Abstract: This paper evaluates an advanced control technique for use with high kVA shunt active filters. the control technique introduces additional rotating frames of reference for each harmonic that is to be compensated. These transform previously oscillatory current references to dc values, thereby improving the steady state performance of the current controllers. The effectiveness of this technique is verified in simulation using SABER (TM).
	Active Power Filter with Neutral Current Compensation Based on the Extension of the Instantaneous Active and Reactive Current Component Id-Iq Method   By V. Soares; P. Verdelho	[View]   [Download]
Abstract: This paper presents the control circuit of a three-phase four-wire shunt active power filter with neutral current compensation based on the extension of instantaneous active and reactive curernt component Id-Iq method. The active power filter presented aims to compensate current harmonics of positive and negative sequence including the fundamental current of negative sequence and also all the zero sequence current harmonics. Therefore, acts as an harmonic, unbalanced and neutral current compensator. The control method used has an excellent harmonic compensation performance and presents the advantage of being frequency-independant. The neutral current compensation is achieved using a 4-leg voltage source converter controlled with a space vector technique. The DC voltage regulation system is analysed and its synthesis is performed. Simulation results are presented to show the stability of the voltage regulation system and to highlight the current compensation performance.
	Analysis and Design of Active Series Voltage Compensator with Harmonic Current Compensation   By S-Y. Lee; J.-S. Cho; H.-S. Mok; G.-H. Choc; Y.-B. Cho	[View]   [Download]
Abstract: A new 3-phase active input unbalance voltage compensator with harmonic current compensating capability is propposed and the operating principle of the proposed system is presented through per-phase equivalent circuit. the proposed system performs both compensations of the unbalanced source voltage and the harmonic currents generated due to nonlinear load such as diode rectifier. The proposed system is composed of a 3-phase voltage source converter, LC filter, series transformer and passive device at the load side of the line. The compensating voltage to regulate the load voltage and to remove the harmonic current components at the source side is transmitted to the line by the series transformer. The control algorithm is suggested and the design of the power circuit is carried out in this paper. The validity of the proposed system is proved by the results of computer simulation using PSIM (Power Simulation).
	Analytical Calculation of Harmonic Distortion Produced by AC/DC Controlled Converters   By G.A. Orcajo; M. F. Cabanas; J. M. Cano; M. G. Melero; F. R. Faya	[View]   [Download]
Abstract: The use of non-linear loads, especially AC/DC converters, in electric supply networks leads to the transmission of high levels of power under nonsinusoidal conditions. A set of simplified mathematical expressions have been studied in order to predict the harmonic content in the input current of DC and AC motor drives. The evolution of the harmonic content in the input current of the converter is then studied in relation to the operating point of the converter and the total reactance associated to the loop current.
	Direct Harmonic Control Method for Active Power Filters   By S. N. Kalachnikov	[View]   [Download]
Abstract: A novel control method for an active power filter is presented, which makes it possible to control the individual harmonics of the supply current with a closed loop. This method makes it possible to reduce the rating of active filters, and as a result, to reduce the cost of them, compared to the conventional control methods.
	Evaluation of Performance Criteria of Hybrid Active Filters   By V. Valouch	[View]   [Download]
Abstract: Three configurations of hybrid filters with two active parts are analyzed and compared in terms of the total harmonic distortions of the mains current and load voltage, and in terms of demanded rated values, mainly powers, of the active parts of these filters. The performance criteria, taking antagonistic points of view into consideration, have been determined and applied.
	Evaluation of Power-Ratings for Active Power Quality Compensators   By D. D. Bester; A. D. le Roux; H. du T. Mouton; J. H. R. Enslin	[View]   [Download]
Abstract: The optimal power rating of a power quality compensator is important not only in the design of an industrial compensator for a specific application, but also in determining the best compensation strategy for a specific application. Different compensator topologies can often perform related compensation functions, resulting in a situation where financial implications determine the best solution. This paper will focus mainly on load voltage regulation with emphasis on dip compensation. The cost of a compensator of a specific topology is not only determined by the power rating of the converters but is also influenced by structural differences such as the addition of injection transformers, energy storage devices or bypass switches. This paper will not directly evaluate the cost of different compensation strategies, but will highlight the differences that will have a marked financial impact. Several implementation issues are also discussed to aid the decision on the optimal compensator solution for a specific application.
	New Optimisation Techniques for Active Filters   By M. Welsh; P. Mehta; M. Darwish	[View]   [Download]
Abstract: In recent years the proliferation of non-linear loads has lead to the development of active filters designed to eliminate current harmonics from the power supply network. This paper examines the switched-capacitor family of active filters, developed at Brunel University, highlighting the complexity of the control technique which limits the effectiveness of this filter configuration. Two different approaches are investigated, with the aim of reducing the computational requirements associated with the control technique and hence increase the applicability of the switched-capacitor active filter. A significant simplification is presented which eases the somewhat laborious, but never the less unavoidable computational requirements. Genetic Algorithms (GA’s) are also investigated providing an alternative to the calculus based techniques which historically have dominated optimisation problems.
	Optimal Placement and Size of a Single Harmonic Filter   By P. Guérin; L. Miègeville; A. Bizien	[View]   [Download]
Abstract: This paper describes an optimization technique to minimize the size of one harmonic filter in distribution systems. The objective is to reduce harmonic voltages with respect to the standards for a minimum power size. Then, an application to a real distribution network is proposed to illustrate the interest of the present method.
	Parallel Active Filter Based on Three Level Inverter   By J. Balcells; M. Lamich; D. González	[View]   [Download]
Abstract: This paper presents the results of simulation of a single phase parallel active filter based on a three level current source inverter. The features of standard two level active filters are compared with those obtained with the three level structure. Different treshold values for the level change are tested in teh control algorithm in order to obtain the optimal solution in terms of response speed and current ripple.
	Performance of Parallel Hybrid Filters in Damping Harmonic Resonance   By R. Li; M. M. Elkateb; A. T. Johns; F. V. Robinson	[View]   [Download]
Abstract: This paper analyses the resonance damping of the parallel hybrid filters. By controlling their outputs, the active filters can be made to behave as variable resistancea and/or inductancea in circuits. When connected in power systems, the operating condition of the complete system can be adjusted dynamically to reduce the risk of resonance. the effect of the bybrid filter configuration and the control strategy has been evaluated on teh resonance damping, as well as harmonic filtering. the frequency characteristics of three parallel hybrid filters topologies are discussed. the principles are validated by simulation and the time-domain results are presented.
	Power Factor Correction in a Co-Generation System   By R. K. Jàrdàn; I. Nagy; E. Raaijen	[View]   [Download]
Abstract: A special application of a co-generation system was developed for producing electrical and heat energy from low pressure saturated steam or some other working medium is presented in the paper. The system consists of a high speed turbine, coupled to a three-phase permanent magnet synchronous generator, a three-phase AC/AC converter and a microprocessor supervisory control unit. The main purpose of the system is to reduce the pressure of the working medium by a turbine instead of throttling valves thus producing electric energy, that can be utilised directly to supply loads in stand-alone mode or feeding it back to existing utility mains. In the latter case the converter connected in parallel to the mains can serve also as a source of reactive ppower and higher harmonic current components, i.e. the converter, by changing its control method, can be turned into a system providing not only active power, but functioning as a complete active filter or ac line conditioner at the same time. Details of the technical solution and results of analyses, comparison of various control strategie are also described in the paper.
	Simulation and Implementation of Three-Phase Active Power Filter with Simple Control Algoritms   By Bor-Ren Lin, Hsin-Hung Lu and Ming-Ta Yang	[View]   [Download]
Abstract: This paper presented a control scheme for three-phase active power filter. Few necessary quantities are measured in the adopted control algorithm. The three-phase current commands which are in phase with mains voltages are derived from the phase lock loop, multiplier, and low pass filter. The conventional instantaneous reactive power theory, synchronous reference frame, and fast fourier transform scheme are generally adopted to obtain the three-phase compensated currents. In this paper, two simple control schemes are used to generate the commands of the compensated currents. The complex calculations in the conventional instantaneous reactive power theory are not needed in the adopted schemes. Three kinds of current control scheme for generating the compensated currents from the voltage source inverter are investigated. The proposed schemes are verified by the software simulation and experimental results from a laboratory prototype.
	Stability of an Active Filter Based on Voltage Feedback   By P. Brogan; R. Yacamini	[View]   [Download]
Abstract: This paper presents the stability analysis of an active filter based on voltage feedback. the active filter, proposed previously by the authors, measures a busbar voltage alone in order to derive the compensation current references. This stability of such a control philosophy, both on purely inductive/resistive systems and for use in systems which contain power factor correction capacitors causing lower order harmonic resonances is then investigated.
	Technical Evolutions and Industrial Applications of Active Filters   By H. Godfroid; S. Tnani; S.R. Jones	[View]   [Download]
Abstract: Electrical supply companies and industrial norms are placing increasing demands on users to ensure low levels of harmonic loading on industrial supply networks. This, coupled with constant developments and improvements in power electronic components and microprocessor control technology, has led to new developments in harmonic prevention and compensation. The paper will describe evolutions in this technology, giving examples, their structure and operational principles as well as results in their industrial applications.
	The Active Differential Current Compensator Controlled by DSP   By M. Gwozdz; R. Porada; L. Frackowiak	[View]   [Download]
Abstract: This paper presents power electronics active compensator, that realises optimal compensation of influence of non- linear load on power network. The principle of compensator operation is elimination of differential current that is defined as difference between load current and reference current (determined by use of optimisation method). The basic scheme and hardware structure of compensator are shown. The compensator utilises the control module with digital signal processor and power electronics controlled current source. The investigations results on laboratory model for current source and active compensator are presented. They confirm its good properties in the meaning of dynamic and stability of work.
	The Evaluation of Current Harmonics in the Context of Filter Design for Distribution Systems with Variable Frequency Drives   By G. A. Orcajo; M. F. Cabanas; J. M. Cano; M. G. Melero; C. H. Rojas	[View]   [Download]
Abstract: The study of harmonic current flow is the most critical stage of filter design. Using mathematical analysis and numerical simulations, this paper investigates the generation of power system harmonics by motor drives. It is shown that harmonic characteristics depend on the mechanical requirements of the load (mechanical torque and reference speed), the electrical conditions of the system (network impedance, filter and motor equivalent circuit), and the control system (rectifier conduction mode and inverter control). The results of harmonic analysis according to the different parameters that influence them are outlined graphically. The paper presents a case study that further emphasizes the importance of harmonic analysis..
	Using Hysteresis Current Control for STATCOM Applications   By P.S. Sensarma; K. R. Padiyar; V. Ramanarayanan	[View]   [Download]
Abstract: The shunt compensation approach for mitigating Power Quality (PQ) problems is popular on account of its simpler ac side coupling and lower insulation requirements. The most versatile shunt compensator is the STATCOM, which is a three-phase, voltage-source inverter, whose output current is to be controlled to achieve PQ compensation. In this paper, some aspects of current control of a STATCOM are investigated. A simple (non-predictive) hysteresis current control scheme is considered. It is shown that, for a given STATCOM, the ac bus voltage largely decides the effectiveness of any simple hysteresis rule. Validity limits of the control laws are analytically derived and both simulation and experimental results are provided in support. Based on these derivations, a simple correction scheme is suggested. Simulation and experimental results confirm improved performance. A digital controller is used for realizing the current control. The dependanceof the current harmonic spectrum on the sampling time is illustrated. Some issues regarding ripple filter design are also discussed.
	Using of the Virtual Air-gap Technique for Active Filtering   By V. Molcrette; F. Lacressonnière; J-L. Kotny; J-P. Swan; J-F. Brudny	[View]   [Download]
Abstract: The aim of the paper is to show the possibility of generating harmonics in the primary winding of a transformer using a phenomenon called ‘ virtual air-gap ‘. These harmonics due to a variable localised reluctance of the transformer core can be used to compensate others induced by a non linear load connected at the transformer secondary. The virtual air-gap is a zone which permeability is adjusted through small additional windings. The frequency spectrum of the current in these windings is controlled so that the magnetisation current of the transformer contains the wished harmonics. The Ampere-Turns law is modified with regard to classical use of a transformer. The experimental verifications of the modified A.-T. law at no-load is presented. Some characteristics of the primary current harmonics under non-linear load are proposed. They show the intrinsic filtering capacity of the virtual air-gap technique. Some conclusions for further developments are finally given.