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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Design and Modeling of Power Factor Correction Circuits

Cheng, Kai-fang 06 July 2005 (has links)
This thesis aims to investigate an active power factor correction (PFC) circuit and its mathematical model, in order to develop a reliable and efficient simulation platform. By using the PI controller, we can control the inductor current and the output voltage of the boost converter. Finally, we constructed the circuit and analyzed the results to verify that our mathematical model is valid.
2

Design and Implementation of High Efficient Active Power Factor Correction Circuits

Fang, Jia-Long 16 October 2006 (has links)
The thesis aims at investigating an active power factor correction circuit. In boost power converter, we ser up average large signal model with Matlab and derive control¡Voutput function for pole assignment of control loop with ac small signal model. In controller, control circuit of conventional active power factor correction and modified PI control circuit are adopted, separately. Through simulation results and experimental responses of hardware circuit show that under variation of load or alternating input voltage, modified PI control circuit has better regulating capacity than that of conventional control circuit .
3

Study of Active Power-Factor Correction Controller Circuits

Wu, Chen-chia 05 July 2005 (has links)
This thesis aims at investigating the technologies of the active power-factor correction (PFC) circuit. The system originally in the article is based on a boost converter circuit as the structure, the control method is to adopt the average current mode. We doesn¡¦t only narrate the circuit principle of the systematic circuit in the article but also use the OrCAD PSpice A/D software to simulation. Finally, we implemented make a prototype circuit and verified the proposed method. The experimental result shows that it can reach the goal for the power-factor correction.
4

Configuration and Analysis of Arrayed Boost-Type Battery Power Modules

Jhan, Jia-fu 06 August 2010 (has links)
This thesis studies the operating characteristics of the boost type battery power modules (BPMs) with series and parallel configurations. Under different operating conditions, the BPMs can be operated at the continuous conduction mode (CCM), the discontinuous conduction mode (DCM), or the hybrid mode with a combination of CCM and DCM. The current distribution and balance discharging among BPMs with different configurations are analyzed in detail. Experiments are carried out to demonstrate the analysis results. Finally, a circuit configuration with arrayed BPMs is proposed for adaptable management and maintenance of a battery power system.
5

Embedded Multilevel Converter Design of a Slotless Tubular Linear Generator for Direct Renewable Energy Extraction

Chen, Chiao-Ru 15 August 2012 (has links)
The objective of this thesis is to design a multilevel converter circuit for driving slotless tubular linear generators (STLG) on retrieving renewable energy application. With the changing speeds and reciprocating directions of the movers, the electric energy generated from the STLG will exhibit large fluctuations and is hard to be used directly. Based on machine modeling and mover reference frame projection, a converter circuit and a data acquisition (DAQ)-based drive control scheme have been developed. From the experimental results, the control scheme implemented on the converter circuit can provide acceptable multilevel dc outputs at various operating modes.
6

Balanced Discharging for Serial Battery Power Modules

Yu, Li-ren 28 August 2012 (has links)
This thesis investigates the discharging behavior of serial boost-type battery power modules (BPMs). Even though the BPMs are connected in series to cope with a higher output voltage, all batteries in the BPMs can substantially be operated individually so that can realize the balanced discharging control strategy. By which, the battery currents are scheduled in accordance with their state-of-charges (SOCs).A battery power system formed by 10 boost-type BPMs is built, in which a micro controller is used for detecting the loaded voltages, estimating the SOCs, and controlling the duty ratios of the power converters. Experimental results demonstrate the balanced discharging capability of the serial BPMs. In addition, fault tolerance mechanism is introduced to isolate fault or exhausted batteries and keep the system working with a reduced load.
7

Charge Equalization for Series-Connected Batteries

Hsieh, Yao-ching 04 January 2004 (has links)
Charge equalization is a major issue in the service of batteries since they are frequently connected in series to obtain higher output voltage levels for most applications. With series connection, imbalance may happen to the operating batteries during either charging or discharging periods. The imbalance among batteries concerns the operating efficiency and the battery lifetime. The main object of this dissertation is to solve the problem of charge inequality. The importance of charge equalization is first addressed. The problem is demonstrated by experiments of charging/discharging processes. Then, the techniques of battery charging and charge equalization are reviewed. To improve charge equalization, a dynamic balance charging scheme is developed on the basis of buck-boost conversion. The balance charging scheme can be realized by two configurations, that is, ¡§forward allotting¡¨ or ¡§backward allotting¡¨ configurations. The circuits are composed of several duplicated subcircuits and operated by digital control kernel, therefore, they are easy to be applied on battery sets with different numbers of batteries. By dynamically re-allocating the energy drawing from satiated batteries and allotted to hungry ones, the series-connected batteries can reach balance state more efficiently. The balance charging circuits can be employed during off-line or even discharging. However, on observing that the output voltage will vary in a big range when the battery set is discharged, the charge equalization can be integrated with voltage regulation on the output. Evolve from this idea, a balance discharging circuit¡@topology based on multi-winding transformer is proposed. The experiments in this dissertation are carried out on lead-acid batteries, therefore, the reactions and characteristics of lead-acid batteries are discussed. However, the proposed circuits are not restricted to be applied on lead-acid batteries only. Experimental results confirm the theoretical analyses and manifest the effectiveness of the designed circuits.
8

Develop DSP-Based Active Power Factor Correction Controller Circuits

Su, Hung-Hsien 20 October 2006 (has links)
The thesis aims to the research of active power factor correction (PFC) circuit and develop a DSP-based digital controller. In the thesis, PI controller is the control core for the voltage loop¡Band current loop, and then achieve the function of the power factor correction of boost converter. Finally, we develop a boost converter and connect it to a DSP-based controller to measure the waveforms and verify the power factor correction. Furthermore, the research can be extended to a simulating platform which we can verify the power factor correction by just changing the control law on DSP .
9

Operation of Battery Power Modules with Serial Connection

Hu, Jin-shin 20 July 2009 (has links)
This thesis presents a novel configuration of battery power by the outputs with serial connection of battery power modules (BPMs) for high voltage level loads. As compared to the conventional application of series-connected battery bank, this configuration operates the BPMs individually, and thus has the advantages of flexible control, convenient maintenance, and easily favorable battery management. The associated converter is equipped to a single battery pack, so that has lower component stresses leading to a higher circuit efficiency. The operation and the design of a lead-acid battery power with series boost-typed BPMs are illustrated. The operation and the design of the converter are illustrated. The control of the power converters is accomplished by a complex programmable logic device (CPLD). To improve the converter efficiency, the technique of synchronous rectification is introduced. For the BPMs designed for discontinuous conduction mode (DCM) operation, charge equalization can be automatically achieved under the same duty-ratio, but is adequate only for batteries with a small difference. On the other hand, charge equalization for the BPMs with continuous conduction mode (CCM) can easily be accomplished by regulating the duty-ratios of the converters.
10

Μελέτη, προσομοίωση και κατασκευή συστήματος διασύνδεσης ανεμογεννήτριας μικρής ισχύος με το δίκτυο χαμηλής τάσης

Περάκης, Κωνσταντίνος 11 January 2011 (has links)
Η παρούσα εργασία πραγματεύεται αφ’ενός μεν τη μελέτη, μέσω προσομοίωσης, ενός αιολικού συστήματος παραγωγής ηλεκτρικής ενέργειας συνδεδεμένο στο δίκτυο χαμηλής τάσης αφ’ετέρου δε την κατασκευή ενός τμήματος του συστήματος αυτού. Το αιολικό σύστημα συγκροτείται από μία ανεμογεννήτρια με σύγχρονη γεννήτρια μόνιμων μαγνητών και διατάξεις ηλεκτρονικών ισχύος που μετατρέπουν αρχικά την εναλλασσόμενη τάση σε συνεχή και στη συνέχεια τη συνεχή τάση σε εναλλασσόμενη, συχνότητας 50Hz, για τη σύνδεση με το δίκτυο. Πιο συγκεκριμένα, χρησιμοποιούνται κατά σειρά μία μη ελεγχόμενη ανορθωτική γέφυρα με διόδους για την ανόρθωση της τάσης, που παράγεται από τη γεννήτρια, ένας μετατροπέας τύπου Boost για την ανύψωση και σταθεροποίηση της τάσης και τέλος, ένας μονοφασικός αντιστροφέας με MOSFET. Η έξοδος του αντιστροφέα, μέσω φίλτρου και μετασχηματιστή, συνδέεται στο δίκτυο. Στόχος είναι η κατασκευή ενός πειραματικού πρωτοτύπου για τη σύνδεση της ανεμογεννήτριας του εργαστηρίου, ισχύος 1kW, με το δίχτυο χαμηλής τάσης, ώστε να χρησιμοποιηθεί για εργαστηριακούς και ερευνητικούς σκοπούς. / This thesis presents the study, modeling and implementation of a wind power system consists of a permanent magnet synchronous generator, a rectifier and boost stage, as well as an inverter stage for grid connection. Control applies on the dc-dc converter aiming at rendering the connection to the electrical power grid more versatile. The analysis was performed by developing an appropriate model for the system at the Matlab computing program aided by the Simulink toolbox of The MathWorks,Inc.

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