Dissertations / Theses on the topic 'Active power filter (APF)'
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Al-Bayaty, Hussein Kamal Anwer. "Novel methods of utilization, elimination, and description of the distortion power in electrical circuits." Thesis, University of Plymouth, 2018. http://hdl.handle.net/10026.1/10646.
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Firstly, this thesis investigates the electrical power harmonics in an attempt to utilize harmonic current and its distortion power in a novel idea to reconvert the distortion power into useful power. This is done, in order to feed different DC or AC loads in single and three-phase power system by using passive or active filters and accordingly, develop a new topology of hybrid active power filter (HAPF). In addition, this circuit can be considered as a power factor corrector (PFC) because it reduces the total harmonic distortion (THD) and improves the power factor (PF). Secondly, this thesis works on a new design of active power factor correction (APFC) circuit presenting two circuits with the same design principle: the first design consists of two active switches without an external complex control circuit, while the second design contains a single active switch with an additional control circuit. The main contribution of this circuit is 98% reduction of the inductor's value used in the newly proposed PFC circuit in comparison with the conventional boost converter which may lead to a huge reduction in size, weight and the cost of the new PFC circuit. Also, the active switches depend on a carefully designed switching pattern that results in an elimination of the third order harmonic from the input source current which decreases the value of total current harmonic distortion (THDI) to (14%) and improves the input PF to (0.99). Consequently, the simplicity of the design without requiring a complex control circuit and without a snubber circuit plus the minimum size of inductor, gives the newly proposed circuit the superiority on other PFC circuits. Thirdly, this research aims to describe the distortion power through submitting two novel power terms called effective active power (Pef ) & reactive power (Qef ) terms with a new power diagram called Right-Angled Power Triangle (RAPT) Diagram. In addition, a novel de nition of total apparent power (St) has been submitted in order to illustrate the physical meaning of (St) in non-sinusoidal systems. The new RAPT Diagram is based on the orthogonality law and depends on geometrical summation to describe the relationship between different aspects (apparent-active-reactive) of power, and different components (total-fundamental distortion), drawing a bridge to connect the time domain with the frequency domain in a two-dimensional diagram.
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Liebig, Sebastian. "Optimization of rectifiers for aviation regarding power density and reliability." Doctoral thesis, Universitätsbibliothek Chemnitz, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-159936.
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The intentions of the so-called "More Electrical Aircraft" (MEA) are higher efficiency and lower weight. A main topic here is the application of electrical instead of hydraulical, pneumatical and mechanical systems. The necessary power electronic devices have intermediate DC-links, which are typically supplied by a three-phase system with active B6 and passive B12 rectifiers. A possible alternative is the B6 diode bridge in combination with an active power filter (APF). Due to the parallel arrangement, the APF offers a higher power density and is able to compensate for harmonics from several devices. The use of the diode bridge rectifier alone is not permitted due to the highly distorted phase current. The following investigations are dealing with the development of an active power filter for a three-phase supply with variable frequency from 360 to 800 Hz. All relevant components such as inductors, EMC-filters, power modules and DC-link capacitor are designed. A particular focus is put on the customized power module with SiC-MOSFETs and SiC-diodes, which is characterized electrically and thermally. The maximum supply frequency slope has a value of 50 Hz/ms, which requires a high dynamic and robustness on the control algorithm. Furthermore, the content of 5th and 7th harmonics must be reduced to less than 2 %, which demands a high accuracy. To cope with both requirements, a two-stage filter algorithm is developed and implemented in two independent signal processors. Simulations and laboratory experiments confirm the performance and robustness of the control algorithm. This work comprehensively presents the design of aerospace rectifiers. The results were published in conferences and patentsHauptziele des sogenannten "More Electrical Aircraft" (MEA) sind Effizienzerhöhung und Gewichtseinsparung. Ein Schwerpunkt hierbei ist die Nutzung von elektrischen statt hydraulischen, pneumatischen und mechanischen Systemen. Die notwendigen Leistungselektroniken haben DC-Zwischenkreise, welche mittels aktiven B6 und passiven B12 Gleichrichtern aus dem Dreiphasennetz gespeist werden. Eine mögliche Alternative ist die B6 Diodenbrücke in Kombination mit einem aktiven Netzfilter, welcher aufgrund der parallelen Anordnung eine höhere Leistungsdichte aufweist und darüber hinaus mehrere Geräte gleichzeitig entstören kann. Die alleinige Nutzung einer Diodenbrücke ist aufgrund des hohen Anteils von Stromharmonischen nicht zulässig. Diese Arbeit beschäftigt sich mit der Entwicklung eines aktiven Filters für ein Dreiphasensystem mit variabler Frequenz von 360 bis 800 Hz. Es werden alle relevanten Bauteile wie Induktivitäten, EMV-Filter, Leistungsmodule und Zwischenkreiskondensator ausgelegt. Besonderes Augenmerk liegt auf dem kundenspezifischen Modul mit SiC-Dioden und SiCMOSFETs, welches vollständig elektrisch und thermisch charakterisiert wird. Die Änderung der Netzfrequenz beträgt bis zu 50 Hz/ms, was eine hohe Dynamik und Robustheit von der Filterregelung verlangt. Weiterhin ist im statischen Fall eine hohe Genauigkeit gefordert, da die 5. und 7. Harmonische auf unter 2% geregelt werden müssen. Um beiden Anforderungen gerecht zu werden, wird ein zweistufiger Regelungsalgorithmus entwickelt der auf zwei digitalen Signalprozessoren implementiert wird. Simulationen und Labormessungen bestätigen die Robustheit des Regelungskonzeptes. Diese Arbeit stellt umfassend die Entwicklung von Luftfahrtgleichrichtern dar. Die Ergebnisse wurden in Konferenzen und Patenten veröffentlicht
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Othman, Mohd Ridzal. "DSP-based active power filter." Thesis, Loughborough University, 1998. https://dspace.lboro.ac.uk/2134/6966.
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Harmonics in systems are conventionally suppressed using passive tuned filters, which have practical limitations in terms of the overall cost, size and performance, and these are particularly unsatisfactory when large number of harmonics are involved Active power filtering is an alternative approach in which the filter injects suitable compensation currents to cancel the harmonic currents, usually through the use of power electronic converters. This type of filter does not exhibit the drawbacks normally associated with its passive counterpart, and a large number of harmonics can be compensated by a single unit without incurring additional cost or performance degradation. This thesis investigates an active power filter configuration incorporating instantaneous reactive power theory to calculate the compensation currents. Since the original equations for determining the reference compensation currents are defined in two imaginary phases, considerable computation time is necessary to transform them from the real three-phase values. The novel approach described in the thesis minimises the required computation time by calculating the equations directly in terms of the phase values i. e. three-phase currents and voltages. Furthermore, by utilising a sufficiently fast digital signal processor ( DSP ) to perform the calculation, real-time compensation can be achieved with greater accuracy. The results obtained show that the proposed approach leads to further harmonic suppression in both the current and voltage waveforms compared to the original approach, due to considerable reduction in the computation time of the reference compensation currents.
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Orts, Grau Salvador. "Sistema de compensación mediante filtro activo de potencia con sistema de obtención de las corrientes de referencia selectivo utilizando control 3D-3B SVPWM de la etapa de potencia. Aplicación a sistemas industriales a 4 hilos." Doctoral thesis, Universitat Politècnica de València, 2008. http://hdl.handle.net/10251/3797.
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Esta tesis doctoral trata acerca de los sistemas de compensación activos de conexión en paralelo utilizados para la mejora de la calidad del suministro eléctrico, y de la eficiencia energética en las redes eléctricas de distribución y en las instalaciones, a cuatro hilos. En la presente tesis se desarrolla un nuevo filtro o compensador activo de potencia con la capacidad de seleccionar los fenómenos a compensar, incluyéndose además algunas propuestas que, aplicadas a estos sistemas de compensación, permiten mejorar las prestaciones finales obtenidas.
Se presentan las estrategias de compensación global más utilizadas en compensadores activos y se propone un método de compensación global basado en la norma IEEE Std. 1459-2000. Se realiza un estudio comparativo de las diferentes estrategias de compensación global.
Para la obtención de un compensador selectivo, se proponen dos métodos diferentes para la descomposición de las corrientes de carga y la obtención de las corrientes de compensación. El primer método está basado en la utilización de las conductancias por fase y la conductancia equivalente del sistema trifásico. El segundo se basa en la descomposición de potencias propuesta en la IEEE Std. 1459-2000. Se presenta un análisis de cada uno de los métodos propuestos.
Se presenta el análisis del sistema completo para la implementación del compensador selectivo propuesto. El sistema de control incluye, la utilización de la técnica de la ventana deslizante para la obtención de las corrientes de referencia, el desarrollo de un regulador de corriente de bajo coste computacional, el diseño del regulador para el control del bus dc y el desarrollo de un nuevo modulador vectorial tridimensional 3D-3B SVPWM.
Finalmente, se presentan los resultados de simulación y experimentales del sistema de compensación diseñado, para diferentes tipos de cargas y condiciones de alimentación. Parte de estos resultados han sido presentados, entre otras, en las siguientes publicaciones:
" S. OOrts Grau, S. (2008). Sistema de compensación mediante filtro activo de potencia con sistema de obtención de las corrientes de referencia selectivo utilizando control 3D-3B SVPWM de la etapa de potencia. Aplicación a sistemas industriales a 4 hilos [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/3797
Palancia
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Cheng, Louis. "Efficient DSP-based active power filter." Thesis, Teesside University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.410837.
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Liebig, Sebastian. "Optimization of rectifiers for aviation regarding power density and reliability." Doctoral thesis, Universitätsverlag der Technischen Universität Chemnitz, 2014. https://monarch.qucosa.de/id/qucosa%3A20187.
Full textAbstract:
The intentions of the so-called "More Electrical Aircraft" (MEA) are higher efficiency and lower weight. A main topic here is the application of electrical instead of hydraulical, pneumatical and mechanical systems. The necessary power electronic devices have intermediate DC-links, which are typically supplied by a three-phase system with active B6 and passive B12 rectifiers. A possible alternative is the B6 diode bridge in combination with an active power filter (APF). Due to the parallel arrangement, the APF offers a higher power density and is able to compensate for harmonics from several devices. The use of the diode bridge rectifier alone is not permitted due to the highly distorted phase current.
The following investigations are dealing with the development of an active power filter for a three-phase supply with variable frequency from 360 to 800 Hz. All relevant components such as inductors, EMC-filters, power modules and DC-link capacitor are designed. A particular focus is put on the customized power module with SiC-MOSFETs and SiC-diodes, which is characterized electrically and thermally. The maximum supply frequency slope has a value of 50 Hz/ms, which requires a high dynamic and robustness on the control algorithm. Furthermore, the content of 5th and 7th harmonics must be reduced to less than 2 %, which demands a high accuracy. To cope with both requirements, a two-stage filter algorithm is developed and implemented in two independent signal processors. Simulations and laboratory experiments confirm the performance and robustness of the control algorithm.
This work comprehensively presents the design of aerospace rectifiers. The results were published in conferences and patents.Hauptziele des sogenannten "More Electrical Aircraft" (MEA) sind Effizienzerhöhung und Gewichtseinsparung. Ein Schwerpunkt hierbei ist die Nutzung von elektrischen statt hydraulischen, pneumatischen und mechanischen Systemen. Die notwendigen Leistungselektroniken haben DC-Zwischenkreise, welche mittels aktiven B6 und passiven B12 Gleichrichtern aus dem Dreiphasennetz gespeist werden. Eine mögliche Alternative ist die B6 Diodenbrücke in Kombination mit einem aktiven Netzfilter, welcher aufgrund der parallelen Anordnung eine höhere Leistungsdichte aufweist und darüber hinaus mehrere Geräte gleichzeitig entstören kann. Die alleinige Nutzung einer Diodenbrücke ist aufgrund des hohen Anteils von Stromharmonischen nicht zulässig. Diese Arbeit beschäftigt sich mit der Entwicklung eines aktiven Filters für ein Dreiphasensystem mit variabler Frequenz von 360 bis 800 Hz. Es werden alle relevanten Bauteile wie Induktivitäten, EMV-Filter, Leistungsmodule und Zwischenkreiskondensator ausgelegt. Besonderes Augenmerk liegt auf dem kundenspezifischen Modul mit SiC-Dioden und SiCMOSFETs, welches vollständig elektrisch und thermisch charakterisiert wird. Die Änderung der Netzfrequenz beträgt bis zu 50 Hz/ms, was eine hohe Dynamik und Robustheit von der Filterregelung verlangt. Weiterhin ist im statischen Fall eine hohe Genauigkeit gefordert, da die 5. und 7. Harmonische auf unter 2% geregelt werden müssen. Um beiden Anforderungen gerecht zu werden, wird ein zweistufiger Regelungsalgorithmus entwickelt der auf zwei digitalen Signalprozessoren implementiert wird. Simulationen und Labormessungen bestätigen die Robustheit des Regelungskonzeptes. Diese Arbeit stellt umfassend die Entwicklung von Luftfahrtgleichrichtern dar. Die Ergebnisse wurden in Konferenzen und Patenten veröffentlicht.
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Sedighy, Mohammad. "A robust VSC-based shunt active power filter." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0002/NQ41307.pdf.
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Muthu, Subramanian. "Analysis and control of unified active power filter." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ37357.pdf.
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Schmit, Andrew Paul. "Hybrid Active Power Filter with Output Impedance Control." Thesis, Virginia Tech, 2006. http://hdl.handle.net/10919/79684.
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In an ideal world, unwanted or undesirable effects in a system could and would be completely ignored. In fact, this was the case in mid-80s' PC design when an 80286 microprocessor running at a "blazing" 12 MHz was considered leading-edge technology. As technology continued to push the envelope and ever-faster designs were realized, more demanding software packages were developed and utilized efficiently. These increasingly sophisticated software packages in turn allowed designers of all disciplines to test systems of escalating complexity. These more complex models placed a heavier burden on the hardware, prompting a push for better and faster hardware designs. The cycle repeats to this day.
As such, we are now in an environment where a 1 GHz microprocessor is considered somewhat dated. More importantly, whereas a small 1 nH (1 billionth of a Henry) inductance in a power delivery path was considered inconsequential a decade ago, it is now a barrier to implementing a design. Similarly, the equivalent series inductance (ESL) of a capacitor plays an increasing (and detrimental) role in the behavior and design of today's VRM (Voltage Regulator Module) design. In fact, it is the ESL of the capacitor that hinders proper voltage regulation at high frequencies by increasing the output impedance beyond a desired level.
This dilemma has been recognized and several topologies have been proposed to overcome this problem. One category is improved passive devices, with the latest involving array capacitors to achieve near-zero ESL. As passive devices are almost always preferable to active solutions due to their lower losses, these technologies hold great promise, though they are inherently limited in small-footprint applications.
A second category is the addition of active devices, which involves the use of some filtering technique to inject or absorb current during a fast transient by the use of semiconductor switches connected to a power source. These switching-state topologies have been shown to be prone to unstable oscillations, often caused by over-reactions or over-corrections of one transient prompting the opposite switch to engage its power source. The research goal is to develop a methodology to use active filters to more-seamlessly extend the control bandwidth of today's VRM technology.
A hybrid active power filter is developed which uses bipolar junction transistors (BJT) in the forward-active region to connect a power supply source to the microprocessor. In this way, the switches are used in a way analogous to a dimmer switch (vs. simply 'on' or 'off'). By proper design of the compensator in the feedback loop, the active power filter can be used to suppress transients in any desired frequency range, limited only by the amplifier's current rating and bandwidth. The compensator design's derivation shows the relationship to the output impedance of the active filter. In essence, we are ‘designing' a capacitor with a very low ESL, having more desirable output impedance vs. frequency relationship than either a capacitor, or a more complicated VRM with an extended bandwidth.
Using this design, however, at very high frequencies (i.e., approaching 1 GHz, or one trillion cycles per second) requires state-of-the-art packaging designs to limit unwanted impedances, and also an ultra-wide GHz bandwidth, high-current operational amplifier. Both of these barriers are outside the scope of this research. As is often the case in research efforts, we have not ‘solved' the problem, but have shifted it to a frequency range where the effect isn't problematic.
Experimental results show the use of a hybrid power filter with a VRM with Adaptive Voltage Positioning (AVP) can significantly suppress voltage undershoot during fast transient load current changes. In addition, the design is modified to reduce and possibly eliminate bulk output capacitors. This provides a promising alternative to a Voltage Regulator Module with a very high control bandwidth. Lastly, simulations give an estimate of the required IC design to use an APF to augment packaging capacitors.Master of Science
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Van, Greunen Corneluis Erasmus. "Neutral-point-clamped shunt active filter." Thesis, Link to the online version, 2005. http://hdl.handle.net/10019/1265.
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Booth, Brian. "An Active Power Supply Filter with Ultra Wide Bandwidth." Thesis, North Dakota State University, 2016. https://hdl.handle.net/10365/28281.
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An active transformerless common mode ?lter is designed for use with switching mode power supplies with a switching frequency greater than 1MHz. The ?lter utilizes an ampli?er in a voltage sensing current adjusting architecture to cancel out common mode noise generated by the switching power supply. The ?lter is analyzed using a transfer function, simulation, and measurements. Several possible feedback con?gurations are examined and bene?ts of di?erent con?gurations are explained. The active ?lter is shown to have superior performance to only passive components at frequencies up to 20MHz. Spectral domain, time domain, and S21 measurements are given to show the ?lter?s e?ectiveness.
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Arman, Mahmoud Fayez. "An 'active' passive-filter topology for low power DC/AC inverters." Thesis, Brunel University, 2011. http://bura.brunel.ac.uk/handle/2438/6072.
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This thesis presents a new output passive filter for voltage source inverter applications which is based on a shunt connected single tuned filter topology. The proposed circuit has the advantage of tracing harmonic components wherever its location in the frequency spectrum. The change in the harmonic location might be as a result of a change in the inverter operating frequency. Also, the proposed filter achieves harmonic reduction close to the traditional single tuned passive filter. In order to show the superiority of the proposed model, a comparison is introduced with other self tuning harmonic filters showing merits and drawbacks of each technique. The proposed circuit (when integrated in square wave inverter) has also shown a tremendous reduction in the switching losses in comparison with high frequency Pulse Width Modulation inverter. Mathematical analyses showing the design of the proposed filter together with extensive simulation results to verify the design are also introduced. The practical implementation of the system is presented and the results show excellent agreement with the theory and simulation. In order to appreciate the proposed filter a new method for classifying passive power filters is introduced. The review includes a comparison of these configurations showing their merit and drawbacks.
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Mkhize, Michael. "Design and implementation of a single phase active power filter." Master's thesis, University of Cape Town, 2011. http://hdl.handle.net/11427/11061.
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Various active filter solutions have been proposed in recent years {I], {2], and are still being widely investigated today. This thesis discusses the design and implementation of the shunt AP F topology.
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Li, Ruomei. "Modelling of active filters for improving power quality." Thesis, University of Bath, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.323585.
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Mossoba, Joseph T. "Unit-delay deadbeat control of a high bandwidth active power filter." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/MQ63023.pdf.
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Carastro, Fabio. "Power quality enhancement using a shunt active filter with energy storage." Thesis, University of Nottingham, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.493118.
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Electrical systems are subject to a wide variety of power quality problems which can interrupt production processes, affect sensitive equipment, and cause downtime. Several power quality studies show that harmonics and voltage sags have been identified as the most serious problems facing industrial customers today, especially in small independent grids which employ distributed generation units.
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Mohd, Siam Mohd Fadzil. "The control of a static var compensator and active power filter." Thesis, Heriot-Watt University, 1998. http://hdl.handle.net/10399/1210.
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Fereidouni, Alireza. "Shunt Active Power Filter Enhancement Using Advanced Control and Modulation Techniques." Thesis, Curtin University, 2016. http://hdl.handle.net/20.500.11937/2482.
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This thesis aims to enhance the performance of SAPF by proposing advanced techniques: A new frequency locking complex adaptive linear combiner; A new combined particle swarm optimization adaptive linear combiner; A constant frequency space-vector hysteresis control for two-level SAPFs; Extending the previous proposed modulation technique for three-level neutral-point-clamped (NPC) SAPFs; A new five-level adaptive hysteresis-band technique for five-level NPC-based SAPFs; A new adaptive proportional-integral-type fuzzy logic controller fur fast DC voltage control and reference current generation.
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Narayanasamy, Balaji. "Impedance Mismatching Based Design of Passive and Active EMI Filters for Power Converters." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1461252861.
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Feng, Xiaohu. "Active filter for improving a switched reluctance motor drive's input power quality." Lexington, Ky. : [University of Kentucky Libraries], 2005. http://lib.uky.edu/ETD/ukyelen2005t00346/THESIS2.pdf.
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Thesis (M.S.)--University of Kentucky, 2005.Title from document title page (viewed on January 23, 2006). Document formatted into pages; contains: x, 97 p. : ill. (some col.). Includes abstract and vita. Includes bibliographical references (p. 95-96).
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Malleichervu, Govind N. "PROPORTIONAL FEEDBACK CONTROL OF DUTY CYCLE FOR DC HYBRID ACTIVE POWER FILTER." UKnowledge, 2008. http://uknowledge.uky.edu/gradschool_theses/555.
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This thesis deals with the design and implementation of a feedback control scheme for a DC Hybrid Active Power Filter used to filter harmonics from a Switched Reluctance Motor (SRM) Drive load. Power electronic systems are non-linear & dynamic [1,3,5]. Power electronic systems employ switching circuits to maximize their efficiency at the penalty that switching circuits generate electrical noise called ripple current and voltage or conducted electromagnetic interference (EMI). The ripple current drawn by the power electronic systems needs to be attenuated to an acceptable level. Filters attenuate this to an acceptable level. Traditionally filters with passive inductors and capacitors are used. Active filters contain switching elements in addition to passive inductors and capacitors which reduce overall size of passive components used.
Two control approaches, full-state state space, and plain proportional feedback, are evaluated for this filter. Circuit models are simulated in SPICE and mathematical models are simulated in Matlab/Simulink for evaluating these control approaches. Proportional feedback control was chosen for implementation and the reason for this is provided in the thesis. The active filter was tested with chosen feedback control and experimental results were compared with simulation results. Inferences and scope for further work are finally presented.
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Massoud, Ahmed Mohammed. "Application of the cascaded multilevel inverter as a shunt active power filter." Thesis, Heriot-Watt University, 2004. http://hdl.handle.net/10399/321.
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Ucak, Onur. "Design And Implementation Of A Voltage Source Converter Based Hybrid Active Power Filter." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/12611095/index.pdf.
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This research work is devoted to the analysis, design and implementation of a shunt connected Hybrid Active Power Filter by the use of a lower rated voltage source PWM converter, and a series connected LC passive filter. In recent years, voltage and current harmonics have become a serious problem both in transmission and distribution systems, due to the widespread usage of non-linear loads such as diode/thyristor rectifiers, electric arc furnaces and motor drives. In order to obtain a better performance than those of the conventional passive filter solutions, active power filters (APF) have been worked on and developed. Among various
configurations listed in the literature, conventional shunt connected voltage source active power filter is widely used in industrial applications. Unfortunately, for large power applications, the losses and the rating of the APF increase considerably. As a result, various hybrid filter topologies have been developed which combine the advantages of both passive and active filters.
In this thesis, a shunt connected hybrid active power filter is developed by combining a 4.7 kVA voltage source converter and a 30kVAR 7th harmonic passive filter. The developed system has been implemented to eliminate the most dominant 5th, 7th and 11th current harmonic components existing at 400V low voltage bus of TUBITAK SPACE Technologies Institute. The theoretical and experimental results have shown
that the DC link voltage of the converter and the rating of APF are minimized while keeping the filtering performance satisfactory.
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Zhang, Huibin. "Application of multilevel inverter as shunt active power filter in three-phase three-wire power system." Thesis, University of Strathclyde, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.501797.
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This research investigates application issues of the active power filter to three-phase three-wire systems, with unbalanced, distorted loads where the line impedance gives rise to voltage distortion at the point of common coupling. Five shunt active power filters are investigated: two-level, wye connected cascaded three and five level, and diode-clamped three and five level. Capabilities of the different shunt active power filter topologies to mitigate voltage/current distortion, compensate reactive power, and balance real power from the source are investigated. Results indicate that neutral point clamped multilevel inverters have advantages over wye cascaded multilevel inverters when operating under asymmetrical load conditions.
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Kim, Jong Wan. "Back to Back Active Power Filter for Multi-Generator Power Architecture with Reduced dc-link Capacitor." Diss., Virginia Tech, 2020. http://hdl.handle.net/10919/96638.
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Multi-pulse converters have been widely used for a multi-megawatt scale power generating system to comply with harmonic regulations. Among all types of multi-pulse converters, a 12-pulse converter is the most widely used due to the simple structure, which consists of a delta-delta and a delta-wye phase-shift transformer pair and it effectively mitigates undesirable harmonics from the nonlinear load.
In the early 2000s, a shunt type passive front-end for a shipboard power system was proposed. By shunting the two gensets with 30° phase angle difference, a single phase-shift transformer effectively eliminates 5th and 7th harmonics. It achieves a significant size and weight reduction compared to a 12-pulse converter while keep the comparable harmonic cancellation performance. Recently, a hybrid type front-end was proposed. On top of the passive front-end, 3 phase active power filter was added and an additional harmonic cancellation was achieved to further eliminate 11th and 13th harmonics. However, the performance of both the passive and hybrid type front-end are highly dependent on the size of the line reactor in ac mains.
A back to back active power filter is proposed in this dissertation to replace the phase-shift transformer in the multi-generator power architecture. The proposed front-end does not include phase-shift transformer and the size and the weight of the overall front-end can be significantly reduced. Due to the active harmonic compensation, the back to back front-end achieves better power quality and the line reactor dependency is improved. The number of required dc-link capacitors is reduced by half by introducing a back to back configuration and the capacitor size is reduced by adjusting the phase angle difference of genset to cancel out the most significant voltage harmonics in the shared dc-link bus.
The overview of the existing shunt type front-end is provided and the concept of back to back active power filter is validated by simulation and prototype hardware. The comparison between existing front-end and the proposed front-end is provided to highlight the superior performance of back to back active front-end. The dc-link bus current and voltage ripple analysis is provided to explain the dc-link ripple reduction mechanism.Doctor of Philosophy
The transportation electrification has gained more and more attention due to its smaller carbon dioxide emission, better fuel efficiency. The recent advances in power devices, microcontrollers, and transducers accelerate the electrification of transportation. This trend is shown in the propulsion system in marine transport as well and the electric propulsion system has been widely used to meet the strict environmental regulations. However, the non-linear circuit components such as capacitor and diode in the electric propulsion system draw non-linear current and significantly deteriorate power quality and lead to critical problems such as reduced life span of circuit components Accordingly, a front-end is required to improve power quality. Also, it is desired to have compact and lightweight front-end for installation flexibility and fuel efficiency improvement. In this dissertation, several front-ends using a phase-shift transformer are reviewed and a detailed analysis is provided to help understand the harmonic cancellation principle of the existing front-end through equivalent circuit analysis, quantitative analysis, and a phasor diagram representation. Based on the analysis of the existing front-ends and shipboard power architecture, lightweight and high-performance front-end is proposed and verified by simulation and prototype hardware. The performance, size comparison between existing front-end and the proposed front-end is provided to show the advantage of the proposed front-end.
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El-Habrouk, Mohamed. "A new configuration for shunt active power filters." Thesis, Brunel University, 1998. http://bura.brunel.ac.uk/handle/2438/5241.
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This thesis presents a new power circuit configuration to be used in shunt active power filters. A new control algorithm based on the linear voltage control suitable for the proposed circuit is introduced. The system is analysed both in time and frequency domains. The practical implementation of the system proves its suitability for the proposed task. The switching frequency of the proposed circuit is much lower than that in other active filters. The switching losses are then considerably reduced, in addition to the fact that the switching devices can withstand larger values of currents being switched on and off at lower frequencies which is an advantage to this circuit. The component sizes (capacitors and inductors) in the proposed circuit are also much smaller than those in other filter configurations. In addition, the thesis presents a new method for categorising the active filter systems proposed in the surveyed literature. The survey includes a comparison of these techniques showing their respective merits and drawbacks. The thesis also includes an implementation of a reference current generator that is suitable for single-phase applications without the need for excessive computations. The technique involves a modified Fourier analysis, which is suitable for active filtering applications.
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Waite, Michael James. "Active power filter for unbalanced distribution networks using a flying-capacitor multi-level inverter." Thesis, University of Leeds, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.549738.
Full textAbstract:
Widespread growth of the consumer electronics market and the upward trend in harnessing electrical power from renewable sources has increased the number of power electronic converters connected to utility distribution systems. Power electronic converters offer flexibility in voltage and current control as well as improved energy efficiency, but generate harmonic currents which have detrimental effects on the power system. A particular challenge appears in 4-wire networks where zero-sequence harmonics exist; such currents accumulate in the neutral conductor and pose threats of overheating and failure. This work investigates harmonic compensation using shunt active power filters with specific application to unbalanced distribution networks. Owing to its increased availabil- ity of switching states, the flying-capacitor multi-level inverter (FCMI) is explored; how- ever an additional challenge exists in the balancing of capacitor voltages. Furthermore, synthesis of unbalanced inverter output volt ages necessitates a three-dimensional pulse- width-modulation (3D-PWM) strategy. This work proposes a new modulation scheme, specifically suited to 4-limb FCMIs, which combines 3D-PWM and natural flying-capacitor voltage control. To develop an optimal harmonic compensation strategy, it is important to understand the nature of harmonic distortion experienced in typical distribution systems. New data on harmonics generated by common single-phase appliances are presented and a compre- hensive power-quality study is performed on a typical 4-wire network. Findings are used to develop a computer model which emulates realistic harmonic load current waveforms. The final contribution in this work lies in the development of an unbalanced harmonic extraction technique based on synchronous reference frame theory and a new modified deadbeat controller which compensates delays and improves reference current tracking. In conjunction with the proposed 3D-PWM scheme, the complete control strategy pro- vides compensation of positive, negative and zero-sequence harmonic currents in addition to alleviating phase load imbalance. A bespoke FCMI test rig is developed, providing experimental validation of the proposed system.
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Lam, Chi Seng. "An adaptive low dc-voltage controlled LC coupling hybrid active power filter in three-phase four-wire power systems." Thesis, University of Macau, 2012. http://umaclib3.umac.mo/record=b2580608.
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Terciyanli, Alper. "Design And Implementation Of A Current Source Converter Based Active Power Filter For Medium Voltage Applications." Phd thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12611767/index.pdf.
Full textAbstract:
This research work is devoted to the design, development and implementation of a Current Source Converter (CSC) based Active Power Filter (APF) for Medium Voltage (MV) applications. A new approach has been proposed to the design of the CSC based APF for reducing the converter kVA rating considerably. This design approach is called the Selective Harmonic Amplification Method (SHAM), and is based on the amplification of some selected harmoniccurrent components of the CSC by the input filter, and the CSC control system, which is specifically designed for this purpose. The proposed SHAM has been implemented on the first industrial CSC based APF for the elimination of 11th and 13th current harmonics of 12-pulse rectifiers fed from Medium Voltage (MV) underground cables in order to comply with IEEE Std. 519-1992. 450 kVA rated APF with only 205 kVA CSC rating has been connected to the MV bus via a coupling transformer of 600kVA, 34.5/1.1 kV. The power stage of the CSC based APF is composed of water-cooled high voltage IGBT and diode modules. Reference currents to be generated by the CSC are obtained by the use of a selective harmonic extraction method, by mploying synchronously rotating reference frames for each selected harmonic component. An Active damping method is also used to suppress the oscillations around the natural frequency of the input filter, excluding the harmonic components to be eliminated by APF. Simulation and field test results have shown that SHAM can successfully be applied to a CSC based APF for reduction of converter kVA rating, thus making it a cost- competitive alternative to voltage source converter based APFs traditionally used in industry applications.
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Acharya, Beena Sivyakova. "Realization of high power active filter networks." 1989. http://catalog.hathitrust.org/api/volumes/oclc/20476082.html.
Full textAbstract:
Thesis (M.S)--University of Wisconsin--Madison, 1989.Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 127-128).
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Ming-Ta, Yang, and 楊明達. "Implementation of Digital Active Power Filter." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/27309731383038396886.
Full textAbstract:
碩士國立雲林科技大學
電機工程技術研究所
86
Power electronics have been widely used in ac to dc converters. They own performances of fast response, small volume, and high efficiency, but serious power pollution is also introduced. Traditional solutions are using capacitor and inductor to make up passive filter for solving harmonics problem. To improve system power factor, a reactive power compensator is used to increase the power efficiency and reduce the transmission line loss. Active power filter not only has the properties of reactive power compensator but also simultaneously eliminate harmonic currents. The architecture of active power filter can be classified into series type, chopping type, dual power conversion type, and shunt type. This thesis presented two cases of study of the algorithm compensated-reference-current-computing and the current control techniques of shunt active power filter. There are two methods for the computing compensated reference current. For generating compensated currents three kinds of current control are used. Including 1) three-phase independent hysteresis band control 2) three-phase independent triangular carrier control 3) two-phase dependent d-q axis space vector control. This thesis studies the performance of steady state, dynamic response, and current harmonic spectrum distribution for both methods. The control algorithms are simulated using software SIMNON and tested by experimental prototype hardware based on TMS320C50 DSP. With the high performance DSP chips, most of complex computations can be accomplished in one sampling cycle.
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Wang, Hsing-Liang, and 王興良. "A Novel Digital Active Power Filter." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/53443875569100134945.
Full textAbstract:
碩士國立臺灣大學
電機工程學研究所
87
Recently, the equipment of power electronics have been widely used in industry. These nonlinear loads often produce a lot of harmonics and affect the quality of the power system. In order to reduce the harmonics, passive L-C filters have been widely used in recent years. Since many drawbacks have been observed in passive compensation methods, active power filters will be examined in this work. It is well known that active power filters can not only reduce the harmonic components, but also improve the power factor. It is rather common to have the active filters controlled by using a microprocessor (e.g. 80196KC ) or a digital signal processor (e.g. TDM320). Because personal computers are more and more popular and used widely on automatic control system, an active power filter based on personal computer is developed. In addition, the data acquisition boards of National Instruments and a specific computer language – LabVIEW are also applied in the thesis to eliminate the harmonics produced by power electronics and improve the power factor at the same time. The principle of the active power filter is described first. Then results from simulations and experiments are presented. It is found from the simulations and experimental results that the harmonic currents can be compensated and the power factor can be improved by the proposed active power filter.
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Chien, Yuan-Bor, and 簡源伯. "Study of Three Phase Active Power Filter." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/09929416146281120884.
Full textAbstract:
碩士國立雲林科技大學
電機工程系碩士班
89
As various of solid-state converters are found in a wide variety of end-use applications, voltage distortion and current harmonics produced by power electronics equipment has become a serious problem to be solved in many countries. Recently, active power filter appears to be an attractive method and is employed to replace the conventional passive LC filter for improving power quality. They are classified into shunt APF, series APF, combination of shunt and series APF, and hybrid APF. In this thesis, the basic compensation principles and control algorithms of these APFs are studied and analyzed. At last, simulations are made to confirm the validities of the control algorithm for these active power filters.
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Chan, ZhaoMing, and 陳昭銘. "One Phase Multi-level Active Power Filter." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/44100454809458020705.
Full textAbstract:
碩士聖約翰科技大學
電機工程系碩士班
100
In recent years, nonlinear loads have such as switch-mode power supplies and motor drives have been applied in life widely. These nonlinear that result inharmonic currents and harmonic voltages have become serious problems for both utilities and customers. A shut active power filter based on power electronic technology has been proposed to eliminate harmonics and improve power factor simultaneously. In natural-point-clamp(NPC) structure based on the three-level-pulse width modulation scheme are studied. To compare with two-level-inverter, three-level-inverter gas the advantage of half voltage stress on switching devices for the same dc-link voltage and lower low-frequency harmonics at the same switching frequency. From the viewpoint of cost, the development of three-level inverter for high power drives has less cost than that of two-level inverter. The proposed three-level shunt active power filter is implemented and the experimental results verify the feasibility of system.
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Huang, Hung-Wen, and 黃鴻文. "A Constant Power Based Switching Strategy for Active Power Filter." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/04288265377614934866.
Full textAbstract:
碩士國立中央大學
電機工程學系
85
A new compensating strategy which is simple in concept andease- implemented in hardware would be introduced. That is, force the power system to draw constant power. By this fact,a novel idea is raised, that is, if we can control the utilitypower to source constant power(Of course, there imply that we have assumed the utility power a ideal sinusoidal voltage source), and the sinusoidal current in line frequency should also be obtained.
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Shiu, Jeng-Jang, and 許政章. "Implementation and Verification of High Power Shunt Active Power Filter." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/qjg6bf.
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Lam, Ka-Lok, and 林嘉樂. "Study on Power Balance for Three-Phase Active Power Filter." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/d4kcvn.
Full textAbstract:
碩士國立交通大學
電機工程學系
106
This thesis is presented how three-phase shunt active power filter improve the current distortion caused by the non-linear load, and through its control system to solve the current unbalance and phase fault between three-phase power system. And also discuss when the energy combined to the three-phase power network, how to improve power factor, compensate reactive power at the same time, in another way, when phase fault or current unbalance in system, how system keeping output current normally. For the control method, through the line voltage signal feedback and digital phase-locked loop, system can track the phase voltage correctly , the traditional multi-loop feedback control include the DC bus voltage control and output current control, with the DC voltage feedback and input current feedback and, the active power filter can compensate reactive power and compensate improve power factor, also can keeping output current when phase fault happening in power source. Finally, the proposed control system is implemented in Texas Instruments DSP TMS320F28335 chip to realize the three-phase shunt active power filter control, and the provided simulation and experimental results shows that well performance of the target.
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Muthu, Subramanian. "Analysis and control of unified active power filter." Thesis, 1998. https://dspace.library.uvic.ca//handle/1828/8790.
Full textAbstract:
The combined series and shunt active filters have been proposed to alleviate the power
quality problems at the demand-side power systems. They provide compensation for
load reactive power, load harmonics, unbalanced loads, utility harmonics, utility disturbances
and utility imbalance. However, the conventional approach for the control
of the combined active filter systems have resulted in large operating capacity of the
shunt active filter because reactive power compensation involves only the shunt active
filter. Furthermore, the harmonic mitigation problems are handled mainly by indirect
harmonic compensation schemes rather than direct harmonic isolation schemes.
This thesis presents the analysis and control of Unified Active Power Filter(UAPF)
and proposes a novel concept of load reactive power compensation involving both the
series active filter and the shunt active filter. This new control strategy of the combined
active filter is to achieve the reduction in KVA rating of the shunt active filter
and the optimal operation with increased efficiency. The thesis also applies discretetime
sliding-mode control technique to enhance the performance of the combined
active filter system in terms of fast dynamic response and effective solution to harmonic
mitigation problems. The thesis also presents simulation and experimental
results to provide verification of the proposed UAPF concept.
In this thesis, the involvement of series active filter for reactive power compensation
is achieved by controlling the phase difference between the load voltage and
the utility voltage. The complete steady-state operating characteristics of UAPF are
analyzed with the identification of the different operating modes of UAPF and the
analysis of active and reactive power handled by the active filter components. The
results of the analysis are shown to provide an insight about the load reactive power
compensation by the series and shunt active filter. The reduction in ratings of the
shunt active filter is demonstrated by an apparent power analysis of active filter components.
The results of the analysis are also useful to design and select the optimal
operating point for UAPF.
The performance of UAPF to meet the stringent power quality standards are
realized by applying discrete-time sliding-mode control schemes for the load voltage regulation and the active power factor correction. Various voltage and current control
techniques used for three-phase voltage-source inverters are surveyed to identify the
discrete-time sliding mode control technique as the suitable one. A generalized design
procedure is derived for the control of power converter systems and the control scheme
is extended to the load voltage control of shunt active filter and the line current control
of series active filter. The control algorithms are developed to track a given load
voltage and line current reference signals respectively. The effect of computational
delay in DSP implementation is studied extensively and the control law is designed
with the consideration for the computational delay. The systematic approach for the
design of DC link voltage regulation is also presented in this thesis.
A prototype experimental setup including the power circuit for UAPF and DSP
based control circuit is built to implement the control and to verify the performance
characteristics of UAPF. A real-time control algorithm is developed and is implemented
on a DSP TMS320C40 system with PWM implementation by DMA without
the intervention of CPU.
The steady-state operating characteristics of UAPF is investigated by experiments.
The operation of UAPF at the optimal operating point is shown to reduce the
ratings of the shunt active filter and to improve the efficiency. The steady-state operation
and the dynamic response of discrete-time sliding mode load voltage control
and utility line current control are examined by simulation and experiments. The
invariance property and the robustness property of the discrete-time sliding mode
control are also demonstrated by the experimental results. With the discrete-time
sliding mode control, the compensation characteristics of UAPF are shown to meet
the stringent power quality standards.Graduate
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Chen, Shih-Kai, and 陳詩凱. "Implementation of a two-phase active power filter." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/73119804194733331351.
Full textAbstract:
碩士國立臺灣科技大學
電機工程系
96
The subject of this thesis is to implement a two-phase active power filter (APF) which employed Le Blanc connection transformer to transfer a three-phase source to a two-phase source. The control goals of the APF include eliminating harmonics in the line current, improving power factor of the system, and balancing the load currents of the two-phase source. TMS320F2812 is used as the core controller and some unbalanced nonlinear load are used in this thesis. By sensing the voltage and current signals, the DSP controller calculates the compensation currents for the two-phase source, and then determines the switching patterns with the hysteresis method. The single-phase semi-converter, which is the front power stage of most electric locomotive in Taiwan, is used as the nonlinear load in the proposed system. To deal with this kind of load, this thesis proposes a feedforward compensation that can improve the transient response of the APF during the accelerating and decelerating periods of the electric locomotives. Both simulation and experimental results show the effectiveness of the proposed system.
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lin, Po-Hung, and 林柏宏. "Study of Active Power Filter with Adaptive Control." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/7fd353.
Full textAbstract:
碩士國立成功大學
電機工程學系碩博士班
90
Recently, the problem of power quality aggravation caused by power harmonic produced because of power electronic equipments has been concerned. So this thesis is mainly focused on the improvement of harmonic problem to propose solution. The content in the thesis has two parts: the first is to add a parallel active power filter in system, whose function is to get the same scale and phase of nonlinear load through sensing equipment and then product the combination of the same scale but opposite phase by active filter to cancel the harmonic caused by nonlinear load. Because the phenomenon of signal delay will affect the result of tracking compensated current, in the second part of this thesis it also adds the adaptive control method to solve the above-mentioned problem. In this way it can get more correctly compensated current to improve the effect of harmonic cancellation.
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Huang, Jhong-Wei, and 黃仲維. "A Shunt Active Power Filter for Harmonic Isolation." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/47754233242281222953.
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Chen, Chun-Cheng, and 陳俊丞. "Research of Three Phases Active Power Filter with Power Quality Improvement." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/16503633613437467540.
Full textAbstract:
碩士國立雲林科技大學
電機工程系碩士班
95
Power pollution due to nonlinear loads will result in seriously power problem in power transmission and distribution systems. Therefore, this thesis is studied the Unified Power Quality Conditioner （UPQC） with Neutral Point Clamp（NPC） inverter. The functions of UPQC are inverters to improve power quality and to control power flow. The UPQC can achieve dynamic voltage adjustment, harmonic current elimination, active current compensation, and power factor improvement. Meanwhile, it can also achieve rapidly response at abnormal condition. The proposed control schemes are verified by the extensively simulation results.
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Yang, Bor-ren, and 楊博仁. "Study and Implementation of Single Phase Active Power Filter." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/71312080866944420730.
Full textAbstract:
碩士國立雲林科技大學
電機工程系碩士班
89
With the increasing concern over power quality (at both distribution and consumer levels) and the need to control harmonic, reactive power and voltage stability (at transmission levels), active power filters have attracted considerable interest in recent years. In this thesis, three categories of active power filter are presented. They are shunt active power filter, hybrid active power filter and shunt-series active power filter. Some simulations based on Matlab/Simulink are presented to demonstrate the performance of the adopted active power filter. Finally the hardware circuit consisted of the microprocessor 80196MC and some peripheral circuit are implemented to verify the proposed control scheme.
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Wel, Tsung-Kuan, and 欉冠維. "Development Of Three Phase Multi-level Active Power Filter." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/97889499763964823611.
Full textAbstract:
碩士聖約翰科技大學
電機工程系碩士班
96
With the proliferation of nonlinar loads as diode/thyristor restifiers, nonsinusoidal currents degrade power quality in power transmission/distribution systems. Harmonics in power systems are becoming a serious problem for both utilities and customers. An active power filter using power electronic technology can reduce harmonics and improve power factor simultaneously. In this thesis, a feasibility study of shunt three-level power active filter is reported. Based on the traditional hysteresis current control switching technology for pulse width modulation scheme, a natural-point-clamp (NPC) structure is adapted. Compared with two-level inverters, three-level inverters have half the voltage stress on switching devices for the same dc-link voltage, and generate lower harmonics at the same switching frequency. The proposed three-level shunt active power filter is implemented and the experimental results verify the feasibility of the system and the correction of related analysis.
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Tzung-ShianTsai and 蔡宗憲. "Study on Active Power Filter for Grid-Connected Inverter." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/79435243837572442206.
Full textAbstract:
碩士國立成功大學
電機工程學系
102
The purpose of this thesis is to implement the active power filter which can correct the output current of the grid-connected inverter. In order to mitigate the distortion and improve the efficiency of power transmission, the current fed to the grid should be corrected into a sinusoidal waveform. The circuit of the active power filter is using single phase full-bridge structure. The distortion component of current will be detected by the designed control system to obtain the compensation current command. The current closed-loop control scheme includes PI-controller and triangular carrier control, and the operating stage of active power filter will be changed to get the appropriate compensation current. The control circuit also generates a unity sinusoidal reference signal to make the corrected current to be inphase with mains voltage. The proposed active power filter is simulated by PSIM. A prototype circuit is implemented to show the effect of current correction.
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Ai, Wen-Jei, and 艾文傑. "Development of Three Phase Multi-Function Active Power Filter." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/38925607280339893630.
Full textAbstract:
碩士中原大學
電機工程研究所
89
The object of this thesis is to develop a multi-functional active power filter (APF) that can be multi-module parallel operation. The functions include compensation of the load current harmonics, reactive power and three-phase unbalanced currents aiming that the input currents are balanced with low distortion and the input power factor is unity. As for the control method, the synchronous-frame-based algorithm for reactive power compensation combined with the band-pass filter for harmonic current calculation is adopted for achieving a better filtering performance under the distorted voltage supply. A real power compensation technique is also proposed for balancing the unbalanced load currents. The cascaded series load current sensing method accompanying with the capacity-limitation control (including the reactive power capacity, harmonic current amplitude and unbalanced load power limitations) is employed to make multiple APFs can be paralleled without any control interconnection. A 3KVA APF system is implemented, the effectiveness of the proposed methods are proved in terms of some EMTP simulation and experimental results.
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Li, Chien-Hsing, and 李建興. "A Shunt Active Power Filter Adopting Lyapunov Control Approach." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/97226794328213955465.
Full textAbstract:
博士雲林科技大學
工程科技研究所博士班
98
In this dissertation, a Lyapunov-based current control method is proposed for a single-phase shunt active power filter (APF) to reduce source current harmonics and reactive power. Most studies only show control block diagrams with classic control methods. These control schemes look very attractive for their simplicity and ease of implementation, but lack in presenting an adequate compensation algorithm or stability analysis of active power filters. The control law is derived from directly applying the Lyapunov stability theory to the integral controller, so that the closed-loop systems possess better harmonic current elimination. The proposed APF controller forces the supply current to be sinusoidal, with low current harmonics, and to be in phase with the line voltage. An experimental model of the active power filter has a power rating of 1 kW. The switching frequency of the active power filter is 20 kHz which can be produced by the electronic devices. The power factor is improved from 0.63 to 0.97 and the THD is reduced from 56% to 3.74% with a phase-angle controlled load. Computer simulations and experimental results obtained from a laboratory system developed in this dissertation verify the viability and effectiveness of the full-digital-controlled active filter. The features of the proposed system include: 1) the performance of the APF is much improved when adopting the Lyapunov stability approach. It is easy to select a suitable control gain to achieve stability compensation while maintaining the system stability. 2) Better harmonic compensation performance is obtained because the Lyapunov-based theory is used in the control algorithm, which is very important for active power filters to be used in practical applications.
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Cheng, Po-Tai. "Use of dominant harmonic active filters in high power applications." 1999. http://catalog.hathitrust.org/api/volumes/oclc/44724942.html.
Full textAbstract:
Thesis (Ph. D.)--University of Wisconsin--Madison, 1999.Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 183-191).
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Chen, Chin-Lin, and 陳金鈴. "An Active Power Filter Using Synchronous Detection Method for Unbalanced Power Systems." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/27282146591952397396.
Full textAbstract:
博士國立成功大學
電機工程研究所
83
This dissertation presents a new method, termed as the synchronous detection method, for active power filter to compensate the reactive and harmonic current in an unbalanced three-phase power system. Although the instantaneous power theory is powerful to operate an active filter, an assumption of balanced three-phase source voltage is required. Due to the inherent unbalanced characteristics in distribution feeder system , the synchronous detection method is proposed here to handle the unbalanced voltage to solve the reactive and harmonic current compensation problem. Three alternative methods using equal power , equal line current and equal resistance concept of the synchronous detection method are formulated. By simulation results, the performance of the synchronous detection method is proven to be improved. In this dissertation, results using the equal power, equal line current and equal resistance synchronous detection methods are shown. The d-q compensated component of instantaneous power theory is modified and reformulated for an unbalanced system , and its result is proven to be the same as that of equal resistance synchronous detection method. The formula of synchronous detection method can also be extended to multi- phase systems, such as four-system and six-phase system. System implementation using actual harmonic loads is also presented, as well as the test results. The merits of the proposed method are its capability to operate under unbalanced system by per-phase calculation, to avoid conversion error by force waveform calculation, and to implement in very simple manners. This dissertation has accomplished an active filter design for current compensation and load balancing in an unbalanced three-phase system.
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WU, JIN-CHANG, and 吳晉昌. "A novel active power filter for reactive power compensation and harmonic suppression." Thesis, 1992. http://ndltd.ncl.edu.tw/handle/49140932308585580991.
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