Thèses sur le sujet « UNITY POWER FACTOR CONTROL »
Pour voir les autres types de publications sur ce sujet consultez le lien suivant : UNITY POWER FACTOR CONTROL.
Créez une référence correcte selon les styles APA, MLA, Chicago, Harvard et plusieurs autres
Consultez les 50 meilleures thèses pour votre recherche sur le sujet « UNITY POWER FACTOR CONTROL ».
À côté de chaque source dans la liste de références il y a un bouton « Ajouter à la bibliographie ». Cliquez sur ce bouton, et nous générerons automatiquement la référence bibliographique pour la source choisie selon votre style de citation préféré : APA, MLA, Harvard, Vancouver, Chicago, etc.
Vous pouvez aussi télécharger le texte intégral de la publication scolaire au format pdf et consulter son résumé en ligne lorsque ces informations sont inclues dans les métadonnées.
Parcourez les thèses sur diverses disciplines et organisez correctement votre bibliographie.
1
Tooth, Daniel John. « The behaviour and analysis of a three-phase AC-DC step-down unity power factor converter ». Thesis, Heriot-Watt University, 1999. http://hdl.handle.net/10399/594.
Texte intégral
2
Elmes, John. « MAXIMUM ENERGY HARVESTING CONTROL FOROSCILLATING ENERGY HARVESTING SYSTEMS ». Master's thesis, University of Central Florida, 2007. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3400.
Texte intégralRésumé :
This thesis presents an optimal method of designing and controlling an oscillating energy harvesting system. Many new and emerging energy harvesting systems, such as the energy harvesting backpack and ocean wave energy harvesting, capture energy normally expelled through mechanical interactions. Often the nature of the system indicates slow system time constants and unsteady AC voltages. This paper reveals a method for achieving maximum energy harvesting from such sources with fast determination of the optimal operating condition. An energy harvesting backpack, which captures energy from the interaction between the user and the spring decoupled load, is presented in this paper. The new control strategy, maximum energy harvesting control (MEHC), is developed and applied to the energy harvesting backpack system to evaluate the improvement of the MEHC over the basic maximum power point tracking algorithm.M.S.E.E.
School of Electrical Engineering and Computer Science
Engineering and Computer Science
Electrical Engineering MSEE
3
Upadhyay, Abhishek Kumar. « A GENERALIZED CONTROL METHOD FOR CONSTANT SWITCHING FREQUENCY THREE PHASE PWM BOOST RECTIFIER UNDER EXTREME UNBALANCED OPERATION CONDITION ». Cleveland State University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=csu1449719352.
Texte intégral
4
Malik, Naveed ur Rehman. « Modelling, Analysis, and Control Aspects of a Rotating Power Electronic Brushless Doubly-Fed Induction Generator ». Doctoral thesis, KTH, Elektrisk energiomvandling, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-174349.
Texte intégralRésumé :
This thesis deals with the modeling, analysis and control of a novel brushlessgenerator for wind power application. The generator is named as rotatingpower electronic brushless doubly-fed induction machine/generator (RPEBDFIM/G). A great advantage of the RPE-BDFIG is that the slip power recoveryis realized in a brushless manner. This is achieved by introducing an additionalmachine termed as exciter together with the rotating power electronicconverters, which are mounted on the shaft of a DFIG. It is shown that theexciter recovers the slip power in a mechanical manner, and delivers it backto the grid. As a result, slip rings and carbon brushes can be eliminated,increasing the robustness of the system, and reducing the maintenance costsand down-time of the turbine. To begin with, the dynamic model of the RPE-BDFIG is developed andanalyzed. Using the dynamic model, the working principle of the generatoris understood and its operation explained. The analysis is carried out atspeeds, ±20% around the synchronous speed of the generator. Moreover, thedynamics of the generator due to external load-torque disturbances are investigated.Additionally, the steady-state model is also derived and analyzed forthe machine, when operating in motor mode. As a next step, the closed-loop control of the generator is considered indetail. The power and speed control of the two machines of the generator andthe dc-link voltage control is designed using internal model control (IMC)principles. It is found that it is possible to maintain the stability of thegenerator against load-torque disturbances from the turbine and the exciter,at the same time maintain a constant dc-link voltage of the rotor converter.The closed-loop control is also implemented and the operation of the generatorwith the control theory is confirmed through experiments.In the third part of the thesis, the impact of grid faults on the behaviourof the generator is investigated. The operation of the generator and its responseis studied during symmetrical and unsymmetrical faults. An approachto successful ride through of the symmetrical faults is presented, using passiveresistive network (PRN). Moreover, in order to limit the electrical and mechanicaloscillations in the generator during unsymmetrical faults, the dualvector control (DVC) is implemented. It is found that DVC to a certain extentcan be used to safeguard the converter against large oscillations in rotorcurrents. Finally, for completeness of the thesis, a preliminary physical design ofthe rotating power electronic converter has been done in a finite elementsoftware called ANSYS. The thermal footprint and the cooling capability,with estimates of the heatsink and fan sizes, are presented. Besides, another variant of a rotating electronic induction machine whichis based on the Lindmark concept and operating in a single-fed mode is also investigated. It’s steady-state model is developed and verified through experiments.QC 20151006
5
Tunc, Murat. « A Single Transistor Unity Power Factor Rectifier ». Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12608114/index.pdf.
Texte intégralRésumé :
This thesis analyzes unity power factor rectifiers since this type of rectifiers use energy as efficient as possible. Throughout the thesis, some unity power factor rectifier topologies are investigated and some of them selected to investigate in detail. Afterwards, a new single transistor unity power factor rectifier topology is proposed, simulated, implemented and compared with one of the selected unity power factor rectifier topology on the basis of efficiency, total harmonic distortion, input current ripple and output voltage ripple.
6
Zhou, Zhongfu. « Unity power factor active rectifier and DC bus controller ». Thesis, University of Sussex, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.401482.
Texte intégralRésumé :
A Unity Power Factor Active Rectifier and DC Bus Control system is described in this thesis. The aim of an active rectifier controller is to draw sinusoidal input current with unity power factor, and to provide fast response to DC load disturbance, whilst maintaining the DC link voltage as constant as possible. To achieve this aim, a current control structure based on voltage vector modulation has been developed using both stationary and synchronous reference frames. To improve response speed and stability, reduce transient overshoot, and overcome the drawback caused by the inherent dead time delay in the digital control loop, a Smith Predictor is introduced into the control loop to compensate for the dead time delay. To speed up the response to DC link current disturbance, the control structure incorporates DC bus voltage feedback regulation plus DC link feed-forward current control. For mains supply synchronization, a software digital Phase Locked Loop (PLL) is used, designed for low sensitivity to supply voltage noise. To further improve performance, a double update pulse width modulation (PWM) mode is utilised. To implement feed-forward current control without the need for multiple DC link current sensors and associated communication channels in applications where the common DC bus system feeds multiple variable speed drives, a robust minimum order DC link current observer has been designed to provide the required feed-forward current signal. To investigate the performance of the active rectifier controller, a simulation program based on VissimTM has been developed and simulations carried out for both 20A and 500A step change load currents. An experimental system has been built using a ADMC401 digital signal processor as the control core, and experiments conducted using different control schemes. Both simulation and experimental results show the validity of the control model
7
Mitwalli, Ahmed Hamdi. « A digital controller for a unity power factor converter ». Thesis, Massachusetts Institute of Technology, 1993. http://hdl.handle.net/1721.1/67135.
Texte intégralRésumé :
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1993.Includes bibliographical references (leaves 153-154).
by Ahmed Mitwalli.
M.S.
8
Sazak, Bekir Sami. « A new unity power factor quasi-resonant induction heater ». Thesis, University of South Wales, 1997. https://pure.southwales.ac.uk/en/studentthesis/a-new-unity-power-factor-quasiresonant-induction-heater(f2b62fc5-7178-47c3-9da4-4a96b91ea45a).html.
Texte intégralRésumé :
This thesis reports an investigation into the design of converters for induction heating systems based upon resonant switch mode power converter techniques. The proposed three phase unity power factor induction heating system consists of two stages of power conversions. The important requirements for each stage of the power conversion of a typical induction heating system working from a three-phase supply are identified. A wide range of power converters which fulfil these requirements are compared and evaluated. From the evaluation, the most applicable converter topologies are selected. Each selected converter class is investigated in great detail to outline their advantages and disadvantages. The first stage consists of a push-pull buck converter connected to a unity power factor rectifier stage. This stage converts the three phase AC mains supply to a required DC value. The second stage, which converters the DC into AC is a single ended resonant inverter system. Analysis of the converters has been made and the design procedure has been formulated. The design procedure allows a strenuous design of each resonant converter for particular converter applications. The final converter design has been simulated using the circuit simulation software packages Design Architect and Accusim to verify the results of analysis. The most important design and construction achievements can be summarised as follows: I A novel push-pull buck quasi-resonant converter with a three-phase rectifier stage has been built and tested. At its maximum operating frequency of 40kHz, the prototype converter delivers an output power of 500W. The converter draws nearly sinusoidal currents from the three-phase mains supply and has an input power factor approaching unity. A secondary stage resonant converter provides AC for the induction heater coil. This AC current flowing in the induction coil creates an alternating electromagnetic field for the workpiece. An induction heating coil has been designed and built by using electrical equivalent coil design method. A novel control strategy was developed to provide output power control. Both converter and inverter stage of the system are operated in the zero-current switching condition. The use of this technique allows higher switching frequencies and provides low switching losses. The full design details are presented along with simulation and practical results. The simulation and practical performance results presented show good correlation with theoretical predictions.
9
Douglas, Hugh. « A single three phase variable speed drive with unity power factor ». Master's thesis, University of Cape Town, 2000. http://hdl.handle.net/11427/5274.
Texte intégralRésumé :
Bibliography: leaf 86.The new proposed topology for a single three-phase variable speed drive was developed after considering the advantages and disadvantages of previous topologies. The new topology employs only six switches that form and active front-end rectifier and a four-switch inverter. The active front-end rectifier is the first leg of the three-phase bridge. It not only rectifies the voltage source but it also regulates one of the phases for the motor. The four-switch inverter produces the variable frequency. Excessive distortion currents drawn by a converter can cause voltage distortions. For this reason the converter should draw a high quality sinusoidal current from the supply. Excessive currents drawn from the supply are also the result of poor power factors. The converter should therefore operate at close to unit power factor. N Mohan, T Underland, W.P Robins [3].
10
Eissa, Mohamed O. (Mohamed Omer). « A fast analog controller for a unity power factor AC/DC converter ». Thesis, Massachusetts Institute of Technology, 1993. http://hdl.handle.net/1721.1/106709.
Texte intégralRésumé :
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1993.Includes bibliographical references (leaves 108-109).
by Mohamed O. Eissa.
M.S.
11
Xie, Manjing. « Digital Control for Power Factor Correction ». Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/34258.
Texte intégralRésumé :
This thesis focuses on the study, implementation and improvement of a digital controller for a power factor correction (PFC) converter.
The development of the telecommunications industry and the Internet demands reliable, cost-effective and intelligent power. Nowadays, the telecommunication power systems have output current of up to several kilo amperes, consisting of tens of modules. The high-end server system, which holds over 100 CPUs, consumes tens of kilowatts of power. For mission-critical applications, communication between modules and system controllers is critical for reliability. Information about temperature, current, and the total harmonic distortion (THD) of each module will enable the availability of functions such as dynamic temperature control, fault diagnosis and removal, and adaptive control, and will enhance functions such as current sharing and fault protection. The dominance of analog control at the modular level limits system-module communications. Digital control is well recognized for its communication ability. Digital control will provide the solution to system-module communication for the DC power supply.
The PFC converter is an important stage for the distributed power system (DPS). Its controller is among the most complex with its three-loop structure and multiplier/divider. This thesis studies the design method, implementation and cost effectiveness of digital control for both a PFC converter and for an advanced PFC converter. Also discussed is the influence of digital delay on PFC performance. A cost-effective solution that achieves good performance is provided. The effectiveness of the solution is verified by simulation.
The three level PFC with range switch is well recognized for its high efficiency. The range switch changes the circuit topology according to the input voltage level. Research literature has discussed the optimal control for both range-switch-off and range-switch-on topologies. Realizing optimal analog control requires a complex structure. Until now optimal control for the three-level PFC with analog control has not been achieved. Another disadvantage of the three-level PFC is the output capacitor voltage imbalance. This thesis proposes an active balancing solution to solve this problem.Master of Science
12
Raval, Chintan A. « Three-phase ac-dc power supply design and experiments using a sic based power module ». Thesis, Kansas State University, 2017. http://hdl.handle.net/2097/35520.
Texte intégralRésumé :
Master of ScienceDepartment of Electrical and Computer Engineering
Behrooz Mirafzal
The rise of Wide Band Gap (WBG) devices has brought excitement in the field of Power converters. The WBG based converter can operate at the very high frequency and temperature making them ideal to use in harsh environments. The commercialization of WBG devices such as SiC and GaN MOSFETs has made it interesting for power engineering professionals all over the world. The use of WBG devices capable of operating at high switching frequencies reduces the overall system size dramatically with added benefit of improved power quality at high temperature. The main goal of this thesis is to design and test an AC-DC converter based on a SiC power module. The designed rectifier can be considered an active rectifier equipped with a controller to constantly provide feedback for modification of switching signals to get the desired output voltage. The designed active rectifier converts the varying frequency input power supply into rectified DC voltage while keeping the power factor of the system to unity. This thesis covers elementary information on power supply design, switching schemes and design of the controller. System arrangement will provide more light on the use of Six Channel MOSFET Gate Driver from CREE with the overall experimental setup. The experimental analysis will summarize the behavior of the system where information on achieved rectification, effect on the line currents at the generator and concluding power factor representation is described.
13
Wall, Simon Robert. « Control of switched-mode power converters ». Thesis, University of Cambridge, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.362966.
Texte intégral
14
Clark, Colin William. « Digital control techniques for power quality improvements in power factor correction applications ». Thesis, University of British Columbia, 2012. http://hdl.handle.net/2429/42799.
Texte intégralRésumé :
The prevalence of standards and recommended practices to meet harmonic current limits has gained, and continues to gain, momentum over recent years. To meet these requirements, power electronic rectification devices are necessitated along with their specialized control techniques. A popular power electronic circuit to obtain low-harmonic input current is the boost power factor correction (PFC) converter, and with the advent of digital control, powerful control techniques to meet these harmonic current limits are possible.
The first contribution is a detailed guide to the conversion of an analog IC-controlled boost PFC converter to a digitally controlled equivalent. Design of the voltage and current sensing networks, compensator, overview of the critical interrupt service routines, and the control implementation in a digital signal processor (DSP) is presented. The existing boost PFC converter modified for digital control is successful, and provides a flexible prototyping test bench for further use.
The second contribution is a novel DSP-based discontinuous conduction mode (DCM) detection method for application to the boost PFC converter. The proposed detection method is computationally simple, and requires little or no modification to existing digitally controlled boost PFC converters using DSPs with on-board comparators. An experimental boost PFC converter verifies the effectiveness of the proposed detection method over traditional zero current detection and DCM detection techniques, enabling advanced control techniques for power quality improvements.
The final contribution is a new adaptive mixed conduction mode (MCM) control technique for the boost PFC converter. This MCM control technique applies the proposed DSP-based DCM detection method to realize higher power factor and decreased total harmonic distortion (THD) over a commercially available analog controller and a conventional digital controller. Using a boost PFC converter operating in MCM with the proposed adaptive control method, THD improvements of up to 4.55% at light loads and power factor improvements of up to 17.4% are provided over the analog and conventional digital controller.
15
Pal, Subarna. « Simulation of current mode control schemes for power factor correction circuits ». Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0008/MQ36162.pdf.
Texte intégral
16
Vahidnia, Arash. « Wide area control through aggregation of power systems ». Thesis, Queensland University of Technology, 2013. https://eprints.qut.edu.au/61186/1/Arash_Vahidnia_Thesis.pdf.
Texte intégralRésumé :
This thesis was a step forward in improving the stability of power systems by applying new control and modelling techniques. The developed methods use the data obtained from voltage angle measurement devices which are synchronized with GPS signals to stabilize the system and avoid system-wide blackouts in the event of severe faults.
New approaches were developed in this research for identifying and estimating reduced dynamic system models using phasor measurement units. The main goal of this research is achieved by integrating the developed methods to obtain a feasible wide-area control system for stabilizing the power systems.
17
Yao, Yanmei. « Study of Induction Machines with Rotating Power Electronic Converter ». Doctoral thesis, KTH, Elkraftteknik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-196054.
Texte intégralRésumé :
This thesis investigates a novel induction machine topology that uses a rotating power electronic converter. Steady-state and dynamic performance of the topology is studied to understand its operational principle. Furthermore the potential of improving its efficiency and power factor is investigated. The topology is referred to as wound rotor induction machine with rotating power electronic converter (WRIM-RPEC). The WRIM-RPEC topology offers the possibility to magnetize the induction machine from the rotor side by introducing a reactive voltage in the rotor. Thus, the power factor of the machine can be improved. Constant speed variable load operation can be achieved by setting the frequency of the introduced voltage. Two options of rotor winding and converter configuration in the WRIM-RPEC system are investigated. The wound rotor windings can either be open-ended and fed by a three-phase back-to-back converter or Y-connected and fed by a single three-phase converter. The dc-link in both converter configurations contains only a floating capacitor. These two configurations give different dc-link voltages at the same torque and speed. Two analytical steady-state models of the topology are developed in this thesis. The first model can be used to analyze the operating condition of the motor at specific speed and torque. Particularly, the operating range of speed and torque of the topology is investigated. The second model is used to analyze variable power factor operation, including unity power factor operation. Analytical calculations and measurements are carried out on a 4-pole, 1.8kW induction machine and the results are compared. A dynamic mathematic model is then developed for the WRIM-RPEC system for the back-to-back converter configuration. The mathematic model is then applied in Matlab/Simulink to study the dynamic performance of the system including starting, loading and phase-shifting. The simulation results are compared with measurements on the 4-pole, 1.8kW induction machine. Moreover, the simulation model using the existing Simulink blocks are studied to compare with the results obtained from the mathematic model. Furthermore, the dynamic performance of the WRIM-RPEC system with the single converter configuration is investigated. In addition, harmonic spectra analysis is conducted for the stator and rotor currents. In the last part of the thesis, efficiency improvement is investigated on the 4-pole induction machine when it is assumed to drive a pump load. It is shown that the efficiency can be further improved by decreasing the rotor resistance. Due to space constraints it is however difficult to decrease the rotor resistance in a 4-pole induction machine. An investigation is thus carried out on a standard 12-pole, 17.5kW squirrel-cage induction machine with inherent low power factor. The cage rotor is redesigned to a wound rotor to enable the connection of converter to the rotor windings. An analytical model is developed to design the wound rotor induction machine. The machine performance from calculations is then compared with FEM simulations with good agreement. The analytical model is further used to design several WRIMs with different dimensions and rotor slot numbers. Power factor and efficiency improvement is then explored for these WRIMs. A promising efficiency increase of 6.8% is shown to be achievable.QC 20161111
18
Leskarac, Dom. « Investigation of STATCOMs and Energy Storage Systems in Smart Microgrids ». Thesis, Griffith University, 2018. http://hdl.handle.net/10072/382735.
Texte intégralRésumé :
This thesis presents a hybrid AC/DC microgrid (H-MG) topology that integrates bidirectional, four-quadrant, static synchronous compensators (STATCOMs), high voltage lithium-based energy storage and managed, high-frequency, step-up DC/DC solar converters. Using this topology, an actual H-MG was built and studied to find an efficient solution to peak-demand energy management, increase renewable/distributed energy penetration, and support electric vehicle (EV) integration with commercial buildings. An H-MG testing facility was constructed in a test building at Griffith University to assess and integrate the different elements involved in constructing distribution architectures that combine both AC- and DC-based electrical networks. The facility comprised a total of 15.5 kW of reconfigurable solar photo-voltaic (PV) modules and 80 kWh of reconfigurable lithium energy storage with a variable, 145 kVA, unbalanced, three-phase, commercial building load.
The DC element in the H-MG was formed by a combination of managed DC/DC converters and a lithium battery module. The base parameters of the DC bus were dependent on the AC component of the network, as a single- or three-phase AC supply determined the base DC bus voltage. The base DC bus voltage then deviated based upon the state of charge (SoC) of the lithium battery. Managed solar PV DC/DC converters were placed in parallel and set to follow the SoC voltage characteristics of the lithium battery. The DC/DC converters utilised maximum power point tracking (MPPT) and were placed in parallel to provide direct distributed generation charging functionality for the battery. A STATCOM was directly connected to the DC bus, enabling four-quadrant operation to improve power quality and reduce the peak demand of the building. Utilising both high-power AC and DC, plug-in EVs (PEV) can be a burden or benefit to electricity networks. Using vehicle-to-grid (V2G) connectivity, a PEV can perform similar power quality and peak demand reduction functionality if a bi-directional AC or DC connection is present.
This research successfully implemented and operated a managed DC/AC hybrid microgrid with a four-quadrant STATCOM and DC/DC coupled solar PV array on a commercial building at Griffith University. The system provided voltage regulation and a unity power factor in the connected phase during different modes of strategic operation. Power factor control of the building was also achieved during both discharging and charging of the connected energy storage system.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Eng & Built Env
Science, Environment, Engineering and Technology
Full Text
19
Abdulahi, Mohamed Abdirahman, et Wännström Aksel. « Quality Control of Light Emitting Diodes : Using power factor, harmonic distortion and light to power ratios ». Thesis, Uppsala universitet, Fasta tillståndets elektronik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-301196.
Texte intégralRésumé :
This study addresses quality control for Light Emitting Diodes (LED) according to fouraspects, the power factor of LED lamps, their harmonics and total harmonic distortion (THD), the luminosity for total power to radiated power ratio. It focuses on four brands and six different LED lamps, and concludes that IKEA's LED lamps pertain as the quality lamp, with a power factor over 0.9, THD less than 4% and a power to radiated light of over 4%.
20
Tam, Kin Seng. « Intelligent power factor controller with new measuring method and fuzzy logic control ». Thesis, University of Macau, 1998. http://umaclib3.umac.mo/record=b1447758.
Texte intégral
21
Grote, Tobias [Verfasser]. « Digital control for interleaved boost power factor correction (PFC) rectifiers / Tobias Grote ». Paderborn : Universitätsbibliothek, 2014. http://d-nb.info/105184813X/34.
Texte intégral
22
Chileshe, C. M. « A converter compensator for power factor control in 3-phase induction machines ». Thesis, Aston University, 1996. http://publications.aston.ac.uk/12244/.
Texte intégralRésumé :
The advent of the harmonic neutralised shunt Converter Compensator as a practical means of reactive power compensation in power transmission systems has cleared ground for wider application of this type of equipment. An experimental 24-pulse voltage sourced convector has been successfully applied in controlling the terminal power factor of a 1.5kW, 240V three phase cage rotor induction motor, whose winding has been used in place of the usual phase shifting transformers. To achieve this, modifications have been made to the conventional stator winding of the induction machine. These include an unconventional phase spread and facilitation of compensator connections to selected tapping points between stator coils to give a three phase winding with a twelve phase connection to the twenty four pulse converter. Theoretical and experimental assessments of the impact of these modifications and attachment of the compensator have shown that there is a slight reduction in the torque developed at a given slip and in the combined system efficiency. There is also an increase in the noise level, also a consequence of the harmonics. The stator leakage inductance gave inadequate coupling reactance between the converter and the effective voltage source, necessitating the use of external inductors in each of the twelve phases. The terminal power factor is fully controllable when the induction machine is used either as a motor or as a generator.
23
Agrawal, Ashish. « Performance of PV Generation Feedback Controllers : Power Factor versus Volt-VAR Control Strategies ». Thesis, Virginia Tech, 2015. http://hdl.handle.net/10919/78088.
Texte intégralRésumé :
The variable nature of photovoltaic (PV) generation can cause voltage fluctuations in power distribution systems. Feedback control can be used to minimize the voltage fluctuations. This thesis presents the results obtained from comparing the control performance of two types of PV generation feedback control, namely Volt-VAR control and constant power factor control. A three minute PV generation transient is used to evaluate controller performance, where the transient data used originated from one second measurements taken on an actual PV generator. Using the three minute transient, a set of parametric studies are performed on both feedback control strategies. The performance of the control strategies are compared as to voltage control on the distribution feeder and also to the effect that the control may have on transmission system voltage. In considering transmission system voltage, the reactive power drawn from the substation during the transient is evaluated. Simulation results suggest that the choice of control to be implemented should be based on both transmission and distribution system operational concerns.Master of Science
24
Fan, Philex Ming-Yan. « Power management and power conditioning integrated circuits for near-field wireless power transfer ». Thesis, University of Cambridge, 2019. https://www.repository.cam.ac.uk/handle/1810/290143.
Texte intégralRésumé :
Near-field wireless power transfer (WPT) technology facilitates the energy autonomy of heterogeneous systems, significantly augmenting complementary metal-oxide-semiconductor field-effect-transistor (CMOS) technology. In low-power wearable devices, existing power conditioning integrated circuits do not maximize the power factor (PF) for rectification and power conversion efficiency (PCE) due to multiple conversion. Additionally, there is no core power management for the entire power flow. The majority of the research focuses on active rectifiers, which reduce the turn-on voltage for rectification. Certain studies target the output voltage regulation via feedback to the transmitter or direct battery charging without power maximization. Firstly, this study investigates a high-power factor WPT front-end circuit that is namely the mono-periodic switching rectifier (MPSR) and implemented in a 0.18µm 1.8V/5V CMOS process. Integrated phase synchronizers are used to align the waveshape of a wirelessly-coupled sinusoidal voltage source in a receiving coil to the corresponding conducting current. Using this approach, the PF can be increased from roughly 0.6 to unity without requiring any wireless or wired feedback to the transmitter. The proposed MPSR can also provide AC-DC rectification, and step up and down the sinusoidal voltage source's peak amplitude using a pulse-width modulator. Measured voltage conversion ratios range between 0.73X and 2X, and the PF can be boosted up to unity. Secondly, the wireless power system-on-chip (WPower-SoC) is proposed and implemented in a 0.18µm 1.8V/3.3V CMOS process. The WPower-SoC integrating power management can provide rectification, output voltage regulation, and battery charging. Additionally, the implementation of feedforward envelope detection (FED) can reduce the variation in a wireless power link and improve load transient responses. Simulated results demonstrate that 5% of the output voltage regulation is improved when an output load changes. Moreover, the FED reduces approximately 40% of the transient response time. Overshoot and undershoot voltages are decreased by 23% and 26.5%, respectively. The measured output voltage regulates at 3.42V and can supply output power up to 342mW. A temperature sensor as part of the power management core remains active when the WPT receivers enter sleep mode to prolong the battery usage time. In the final part of this study, a nano-watt high-accuracy temperature sensing core is implemented in a 0.18µm 1.8V/3.3V CMOS process that can self-compensate the temperature shift without the need for additional compensating techniques that consume extra power.
25
Fu, Dianbo. « Improved Resonant Converters with a Novel Control Strategy for High-Voltage Pulsed Power Supplies ». Thesis, Virginia Tech, 2004. http://hdl.handle.net/10919/34432.
Texte intégralRésumé :
The growing demand for high voltage, compact pulsed power supplies has gained great attention. It requires power supplies with high power density, low profile and high efficiency. In this thesis, topologies and techniques are investigated to meet and exceed these challenges.
Non-isolation type topologies have been used for this application. Due to the high voltage stress of the output, non-isolation topologies will suffer severe loss problems. Extremely low switching frequency will lead to massive magnetic volume. For non-isolation topologies, PWM converters can achieve soft switching to increase switching frequency. However, for this application, due to the large voltage regulation range and high voltage transformer nonidealities, it is difficult to optimize PWM converters. Secondary diode reverse recovery is another significant issue for PWM techniques.
Resonant converters can achieve ZCS or ZVS and result in very low switching loss, thus enabling power supplies to operate at high switching frequency. Furthermore, the PRC and LCC resonant converter can fully absorb the leakage inductance and parasitic capacitance. With a capacitive output filter, the secondary diode will achieve natural turn-off and overcome reverse recovery problems. With a three-level structure, low voltage MOSFETs can be applied for this application. Switching frequency is increased to 200 kHz.
In this paper, the power factor concept for resonant converters is proposed and analyzed. Based on this concept, a new methodology to measure the performance of resonant converters is presented. The optimal design guideline is provided.
A novel constant power factor control is proposed and studied. Based on this control scheme, the performance of the resonant converter will be improved significantly. Design trade-offs are analyzed and studied. The optimal design aiming to increase the power density is investigated. The parallel resonant converter is proven to be the optimum topology for this application. The power density of 31 W/inch3 can be achieved by using the PRC topology with the constant power factor control.Master of Science
26
Hernandez, Michael. « Applications of modern control in power electronics ». Paris 11, 2010. http://www.theses.fr/2010PA112161.
Texte intégralRésumé :
Dans la première partie, cette dissertation continue le cadre pour l'analyse et la conception (probablement des compensateurs de facteur) de puissance (PF) non linéaire pour les systèmes électriques fonctionnant dans des régimes nonsinusoïdaux (mais périodiques) avec les charges non linéaires. En particulier, dans la prétention standard que le générateur est une source de tension sans l'impédance, nous avons caractérisé toutes les charges non linéaires dont le pf est amélioré avec un compensateur non linéaire indiqué. Et ce cadre est employé pour étudier le problème de lacompensation passive de pf d'un redresseur commandé par pont classique. Est donné le fonctionnement "à l'avance de phase" du redresseur qu'on s'attend à ce que la compensation capacitive améliore le pf. Il est cependant moins évident que ceci puisse également être réalisé (dans quelques conditions appropriées) avec des inducteurs. Dans la deuxième partie, on a proposé la méthodologie d’A pour concevoir les contrôleurs (PI) proportionnel-intégraux linéaires utilisés des applications de convertisseur de puissance et en assurant la stabilité asymptotique. La technique s’est fondée sur le fait de base que si un système d’affinage peut être rendu passif avec une commande constante, alors il est stabilisable avec pi. Un état structural a été imposé alors au convertisseur de puissance pour satisfaire l’ancienne propriété avec un résultat passif produit comme combinaison linéaire des états. Cette condition est technique et n’a aucune interprétation physique claire. Ce résultat est prolongé dans trois directions : d’abord, la condition mentionnée ci-dessus est enlevée ; en second lieu, une plus grande classe des convertisseurs (avec des sources extérieures de commutation) est considérée ; troisièmement, la résistance de charge est assumée qu’on propose l’inconnu et un contrôleur adaptatif de pi (avec trois estimateurs différents). La méthodologie est appliquée au problème de la compensation de facteur de puissance d’un redresseur triphasé de source de tension, avec des résultats de simulation proposés. En outre, pi adaptatif stable est conçu pour la régulation de tension de rendement d’un convertisseur quadratique de poussée montrant l’exécution au moyen de résultat expérimental. Dans la troisième partie quelques contrôleurs basés sur le concept de la commande de charge pour un convertisseur utilisé dans une mise sous tension la correction de facteur sont montrés. Le convertisseur se compose par le raccordement intercalé de deux convertisseurs ou plus de poussée reliée à la grille à l’aide d’un redresseur de diode non commandé. La commande de charge représente une solution bon marché pour garantir la mise en commun courante entre les différents convertisseurs impliqués, et est normalement employée en combination avec d’autres contrôleurs. Les deux contrôleurs sont d’abord conçus pour garantir le facteur de puissance de près d’un avec la tension CC Réglée, à laquelle la commande de charge est ajoutée pour distribuer le courant égal parmi les convertisseurs. En conclusion, on présente une simplification avec l’exécution semblable qui élimine l’utilisation des sondes courantes, excepté les transformateurs de courant exigés pour mettre en application la commande de charge, des résultats expérimentaux accomplissent cette cloison. La quatrième partie, présente l’exécution et la programmation d’une méthode pour dépister le point de puissance maximum (MPP) dans des applications (PV) photovoltaïques. Ce point de fonctionnement est d’intérêt spécial pendant qu’on l’exige pour extraire la puissance maximum disponible à partir des rangées photovoltaïquesIn the first part, this dissertation continues with the framework for analysis and design of (possibly nonlinear) power factor (PF) compensators for electrical systems operating in non-sinusoidal (but periodic) regimes with nonlinear loads. In particular, under the standard assumption that the generator is a voltage source with no impedance, we characterized all nonlinear loads whose PF is improved with a given nonlinear compensator. And this framework is used to study the problem of passive PF compensation of a classical half-bridge controlled rectifier. Given the “phase advance” operation of the rectifier it is expected that capacitive compensation improves PF, it is however less obvious that this can also be achieved (under some suitable conditions) with inductors. In the second part, A methodology to design linear proportional-integral (PI) controllers used in power converter applications and ensuring asymptotic stability was proposed. The technique relied on the basic fact that if an affine system can be rendered passive with a constant control, then it is stabilizable with a PL A structural condition was imposed then on the power converter to satisfy the former property with a passive output generated as a linear combination of the states. This condition is technical and has no clear physical interpretation. This result is extended in three directions : first, the aforementioned condition is removed ; second, a larger class of converters (with switching external sources) is considered ; third, the load resistance is assumed unknown and an adaptive PI controller (with three different estimators) is proposed. The methodology is applied to the problem of power factor compensation of a 3-phase. Voltage source rectifier, with simulation results proposed. Also, a stable adaptive PI is designed for the output voltage regulation of a quadratic boost converter showing the performance by means of experimental result. In the third part some controllers based on the concept of charge control for a converter used in an application of power factor correction are shown. The converter is composed by the interleaved connection of two or more boost converters connected to the grid by means of a non controlled diode rectifier. Charge control represents a cheap solution to guarantee current sharing among the different converters involved, and is normally used in combination with other controllers. The two controllers are first designed to guarantee the power factor close to one with regulated DC voltage, to which charge control is added to distribute equal current among the converters. Finally, a simplification with similar performance is presented that eliminates the use of current sensors, except for the current transformers required to implement the charge control, experimental results complete this part. The fourth part presents the implementation and programming of a method to track the maximum power point (MPP) in photovoltaic (PV) applications. This operation point is of special interest as it is required to extract the maximum power available from the photovoltaic arrays
27
Chi, Hsiao-Ping, et 齊孝平. « A study on indirect current control of three phase converter with unity power factor ». Thesis, 1993. http://ndltd.ncl.edu.tw/handle/54074645036558003792.
Texte intégralRésumé :
碩士國立成功大學
電機工程研究所
81
For a PWM ac-to-dc converter, an indirect current control strategy is proposed. It is capable of :(1) unity and even leading or lagging power factor, (2) nearly sinusoidal current waveform, (3) bilateral power transfer, and (4) saving the cost of the current transducer.However, there are two disadvantages as follows:(1)the series resistance and the DC filter capacitor in the line will affect the system dynamic stability, and (2) mutual inductance of three-phase inductor will result in the error of the constant and thereby cause the phase shift of the input current. This thesis proposes some strategies to improve the above shortages. The results of the simulation and the experiment both show the correctness of the proposed strategies .
28
Juinne-Ching, Liao, et 廖峻慶. « Instantaneous Power Balancing Control for an Integrated Rectifier/Inverter Fed Three-Phase Induction Servo System with Unity Power Factor ». Thesis, 2000. http://ndltd.ncl.edu.tw/handle/41320376480854219580.
Texte intégralRésumé :
博士國立臺灣科技大學
電機工程系
88
This dissertation presents a novel method of instantaneous power control for the integrated rectifier/inverter fed three-phase induction servo motor. Two identical pulse-width modulation (PWM) converters are used to serve as power regulator with unity power factor and servo motor drive using indirect field-oriented control, respectively. By introducing the synchronous rotating-frame current regulators and the voltage decouplers, both the input and output currents of the integrated system are characterized by fast current response and low harmonic distortion. A novel input-output instantaneous power balancing approach is proposed to improve the dynamic response of input power regulation during load variation in order to minimize the dc-link capacitance. The analytic power models are established for the different input power control methods. The effects of the dynamic responses using different input power control methods are compared and the systematic design and analysis of the proposed method are also presented. The proposed system is implemented with a 1.5kW induction motor. The experimental results show that a near-unity power factor is achieved and the regenerative power can be sent back to the source while motor is braking. By the feedforward power control strategy, only a small dc capacitance about 470 mf is needed for the dc-link capacitor. The dynamic dc-link voltage response of the proposed power estimation method is superior to that of the power feedback method in the transient state. Finally, the analytic results obtained are verified experimentally.
29
SAROA, HARSHA. « SIMULATION AND CONTROL OF PWM CONVERTER FED INDUCTION MOTOR DRIVES ». Thesis, 2014. http://dspace.dtu.ac.in:8080/jspui/handle/repository/15608.
Texte intégralRésumé :
The need for studies of control strategies for induction motor drives is
justified with the proliferation of application of these drives in industries and
production plants where materials have to be both processed and transported and
where a high productivity is one of the key factors. This work is focused on
developing effective control strategies and configurations for control scheme of
industrial induction motor drives. The work is extended to harmonics and reactive
power control of the industrial induction motor drive with a PWM converter. The
proposed control strategy is analyzed and confirmed by the simulation studies of the
mathematical models used.
The complete mathematical model of field orientation control (FOC) and
direct torque control (DTC) of induction motor is described and simulated in
MATLAB for studies of 200 hp cage type induction motor drives. The indirect
vector controlled induction motor drives involve decoupling of the stator current in
to torque and flux producing components. PI control is used for the estimation of the
instantaneous magnitude of the rotor speed, current and torque. The direct torque
control employs direct control of stator flux linkages and the electromagnetic torque
by the selection of an optimum voltage vector.
The pulse width modulated (PWM) converter designed as controllable
switching pulses generator offers a flexible solution to the problem of current
harmonics and reactive power requirement of the designed industrial drives. The
dissertation successfully demonstrates the field oriented control and direct torque
control fed with a PWM converter topology. Both motor control strategies are
compared to decide the performance of the motor.
30
-Yi, Jhang Jian Jyun, et 張簡駿逸. « AC-DC Power Converter with Unity Power Factor ». Thesis, 2013. http://ndltd.ncl.edu.tw/handle/42464490460403641181.
Texte intégralRésumé :
碩士國立高雄海洋科技大學
微電子工程研究所
101
In this paper, an AC-DC power converter with unity power factor is proposed. The proposed AC-DC power converter is configured by two cascade–connected power factor correctors, a buck power converter and a forward power converter. One of power factor correctors is switched in high-frequency pulse-width modulation, and the other one is switched in the frequency the that of input AC voltage. Accordingly, the cascade operation of two power factor correctors can generate a five-level AC voltage in the input terminal so as to reduce the capacity of input filter. As compared with the conventional power factor corrector, the output voltage of power factor corrector in the proposed AC-DC converter is reduced by half. Thus, the switching voltage of high-frequency power factor corrector is also reduced by half. Hence, the switching power loss of high-frequency power factor corrector is reduced and the electromagnetic interference of AC-DC power converter is alleviated. In addition, the input current of AC-DC power converter will be controlled by the high-frequency power factor corrector to be a sinusoidal waveform in phase with the input AC voltage so as to attain unity power factor. The buck power converter and the forward power converter are applied to integrate the output voltages of power factor correctors to an output voltage supplying to the load. A prototype with a digital signal processor based controller is developed and tested to verify the performance of the proposed AC-DC power converter.
31
Xie, Wu-Xiong, et 謝武雄. « Modelling and design of SMR converter with unity power factor ». Thesis, 1991. http://ndltd.ncl.edu.tw/handle/08987106144180835505.
Texte intégral
32
Zargari, Navid Reza. « AC/DC power conversion schemes with unity power factor and minimum harmonic distortion ». Thesis, 1995. http://spectrum.library.concordia.ca/4758/1/NN01278.pdf.
Texte intégralRésumé :
In most line-interfaced power converter applications the ac mains voltage is first rectified into a dc voltage or current, which is subsequently converted into voltages and currents of appropriate amplitude, frequency and shape to meet the load requirements. The front-end rectifier must satisfy three main requirements: (a) Minimum harmonic injection into the ac mains should comply with limits imposed by recommended standards such as IEEE-519, IEC-555. (b) High input power factor to reduce the reactive power requirements. (c) High efficiency and reliability and low cost to ensure competitiveness on the market. The challenge is therefore to provide a conversion scheme which delivers high quality output waveforms without distorting the ac mains and without drawing any reactive power. Successful application of PWM techniques to forced commutated converters has prompted recent investigation in finding more suitable topologies for ac to dc conversion. Two structures have evolved based on the characteristics of the dc link: the current source topology and the voltage source topology. This thesis investigates these two topologies and proposes a number of control schemes to achieve unity displacement factor operation and fast response. For the current source topology two control methods, a closed loop and a feed-forward scheme, are proposed. The feed-forward scheme is based on phase shifting and gating patterns of individual switches to compensate the effect of the input filter and load operating point. Furthermore, the feed-forward scheme is combined with a control strategy to eliminate the need for damping resistors. For the voltage source topology, a simple control strategy is proposed to obtain a near unity power factor input stage for voltage source inverter based ac drive applications. Also, performance of current controlled voltage source type rectifiers in rotating and stationary frames is investigated. Small signal models are developed for both topologies and different transfer functions are derived for each structure. The theoretical considerations are verified by simulation and by experiments on laboratory prototypes.
33
CHEN, ZI-MING, et 陳子明. « Studies and design of an uninterruptible power system with unity factor ». Thesis, 1991. http://ndltd.ncl.edu.tw/handle/15756598080416211785.
Texte intégral
34
GOYAL, ROHIT. « CONTROLLER DESIGN FOR UNITY POWER FACTOR SUPPLY TO INDUCTION MOTOR DRIVE ». Thesis, 2016. http://dspace.dtu.ac.in:8080/jspui/handle/repository/14477.
Texte intégralRésumé :
Induction motors are widely used in industry and agriculture pumps due to the
fact that they are relatively cheap, rugged and maintenance free. However, they need
reactive power for its operation. Thus, a large reactive power is required to be supplied
and transmitted by the supply to the load. Inorder to improve efficiency of transmission
lines as well as efficiency of induction motor, it is desired to improve the power factor
by reducing the reactive power requirement. This can be done using upf controller
which uses SPWM technique. In the present work, unity power factor on the supply
side is obtained using sinusoidal pulse width modulation.
Further, vector control for the control of speed of induction motor is used in the
present study, which has widespread use in high performance induction motor drives. It
allows, by means of a co-ordinate transformation, decoupling of the electromagnetic
torque from the rotor flux. The decoupling control between the flux and torque allows
induction motor to achieve fast transient response. Therefore, it is used in high
performance motor applications. In the present work, an indirect vector control scheme
is implimented with hysteresis current controller.
35
Tseng, Way-Guo, et 曾威國. « Design and Analysis of a Unity Power Factor AC to DC Converter ». Thesis, 1998. http://ndltd.ncl.edu.tw/handle/24474371820216330525.
Texte intégralRésumé :
碩士國立交通大學
電機與控制工程學系
86
The main subject to investigate here is designing a controller make the output voltage follow with the voltage command as soon as possible when loading is variating in AC-DC rectifier with high power factor. To improve the time response by designing a voltage controller, the active full bridge rectifier is adopted. A approximation mathematics model is established by the way of averaging and linearization, and then the adaptive PI Controller and Linear Quadratic Regulator are designed to make the output voltage follow with the voltage command rapidly and stably.
36
Zeng, Wei-Guo, et 曾威國. « Design and Analysis of a Unity Power Factor AC to DC Converter ». Thesis, 1998. http://ndltd.ncl.edu.tw/handle/42196224827257739528.
Texte intégral
37
Cai, Sheng-Nan, et 蔡勝男. « A study on AC-to-DC unity power factor converter using boost converter method ». Thesis, 1991. http://ndltd.ncl.edu.tw/handle/50873981746483858857.
Texte intégral
38
PENG, SHI-XIN, et 彭世興. « Power factor^^and power flow control of an AC/DC converter ». Thesis, 1991. http://ndltd.ncl.edu.tw/handle/19104451906981293484.
Texte intégral
39
LIN, PO-YU, et 林博裕. « Power Factor Control of Permanent Magnet SynchronousWind Generator ». Thesis, 2016. http://ndltd.ncl.edu.tw/handle/60765905477605859681.
Texte intégralRésumé :
碩士明新科技大學
電機工程系碩士班
104
This thesis proposed a novel power factor controller for vertical axis small wind generator. Unlike traditional power factor control method, which uses rotor field-oriented vector control, the control variable is tranformed from the stationary coordinate to synchronous rotation coordinate. By using the synchronously rotating coordinate to design PI controller, the three-phase output phase voltage and current signals of wind turbines can be the same phase. This can increase the efficiency of the wind turbine's output power. First, by using the PLL scheme, we capture the wind generator line voltage angle. Then the phase angle of the phase voltage can be obtained and based on which the current control output signal is calculated in the stationary coordinate. Next, a TMS320 F28335 digital signal processor is used to read the voltage and current signals. After PFC digital control, the wind turbine output current and the voltage can have the same phase. This method does not require the rotor position sensor and therefore cost can be reduced. This method advantage is no rotor position sensor in order to reduce costs. In this thesis, the simulation uses PSIM and a 300W (DS-300) vertical axis wind turbine. The system control core used DSP TMS320 F28335 digital signal processor as, and uses C programming language written. A 300W (DS-300) vertical axis wind turbine is the test subjects to verify the correctness of the closed-loop digital system. In order to verify the feasibility of this system, we used a TECO inverter SPEECON 7200MA to simulate the real environment under different wind speed. Key words: wind generators, PFC Control, phase-locked loop (PLL), PI controller.
40
hao, Lin chih, et 林志豪. « Non-continuous active power factor control IC study ». Thesis, 2010. http://ndltd.ncl.edu.tw/handle/60154363527573422364.
Texte intégralRésumé :
碩士聖約翰科技大學
自動化及機電整合研究所
98
The operation principle of power factor corrector in switching power supply application is that PFC controls the phase and waveform of AC input current to obtain the current waveform as close as possible to mains voltage waveform (a sin wave). To achieve the power factor closes to unity (1). There are two classifications of Power Factor Corrector (PFC): Active PFC and Passive PFC. Active PFC use control IC to regulate the input rectified voltage after bridge to maintain a constant DC bus voltage to gain better power factor above 0.9. A passive PFC requires large inductors and capacitors bank of combination circuit to reduce harmonic current, approximate PF 0.7~0.8 for passive PFC. This paper proposes three different kinds of control IC for discontinuous conduction mode active power factor converter and measured on a same control board for experiment, it’s correct the input current of load so that the current waveform is proportional to the mains voltage waveform to achieve an ideal power factor (PF) value. In the end of this paper – Using three control IC: L6562 of STMicroelectronics, SG6961 of SG (To be renamed to FAN6961 after merger by Fairchild) and Fairchild’s FAN7529. That three IC is integrated in a control panel for testing and researching.
41
Shu, Kuei-Yuan, et 徐貴源. « A Study of Single-Phase Voltage Controllede PWM AC-to-DC Converter with Unity power factor ». Thesis, 1994. http://ndltd.ncl.edu.tw/handle/85787236503117541101.
Texte intégralRésumé :
碩士國立成功大學
電機工程研究所
82
A novel analog-controller is proposed in this thesis for the voltage controlled single phase ac-to-dc converter. The input filter inductor and output filter capacitor of the con- veter are calculated precisely to meet the costumed specifi- cation .In addttion, the minimum output voltage to maintain unity power factor at a specified load is further derived for designing consideration . Finally, 3kW prototype with the proposed analog-controller is implemented , and the results are verified by simulation and experiment.
42
Chang, Kai-Chi, et 張凱棋. « Design of One-Cycle Control Power Factor Correction IC ». Thesis, 2008. http://ndltd.ncl.edu.tw/handle/17593480750445629679.
Texte intégralRésumé :
碩士國立成功大學
電機工程學系碩博士班
96
A one-cycle control based trailing-edge boost type power factor correction IC with instant-switch-current control is proposed in this thesis. It can be utilized to control the front stage of power converter. This control IC is easy to use because only two feedback signals are needed. One is input current and another is output voltage. Multiplier is excluded in this chip. In conventional PFC control chip, the input voltage and load demand are related by using a multiplier. The performance of power factor correction is highly dependent on the precision of multiplier. By using the integrator with reset proposed in one cycle control, the duty ratio can be precisely controlled to lower the total harmonic distortion. Moreover, a level shift circuit is adopted to make this chip work with unipolar supply voltage. For the purpose of better performance, the functions such as leading edge blanking (LEB) and over voltage protection (OVP) are also integrated into the proposed chip. This chip is fabricated with 0.35μm 2P4M 3.3V/5V Mixed Signal CMOS Process.
43
CHEN, JUN-TING, et 陳俊廷. « A Boundary-Mode Boost Power Factor Correction Control IC ». Thesis, 2010. http://ndltd.ncl.edu.tw/handle/90884151565225112837.
Texte intégralRésumé :
碩士國立臺灣科技大學
電子工程系
98
This thesis aims to realize a boundary-mode control IC for single-switch boost power factor correction (PFC) converters. To reduce the low-frequency harmonics of the source current and achieve high power factor, the duty cycle must be regulated according to the ratio of the instantaneous source voltage and the output voltage for each switching period. In this thesis, a novel PFC control scheme with variable duty cycle is proposed. The operation principles and design considerations are analyzed and discussed. Compared with the conventional DCM PFC control method with fixed switching frequency and constant duty cycle, the proposed variable duty cycle control method has many merits such as low harmonics, high power factor, good voltage regulation, high efficiency, and simple circuit. The TSMC 0.35μm 2P4M 3.3/5V CMOS process is adopted for the implementation of this chip. The simulation results under different environment and process variations are shown to verify the feasibility of the proposed scheme.
44
Lin, Chiahsin, et 林嘉新. « Design of Interleaving Non-Linear Control Power Factor Correction ». Thesis, 2011. http://ndltd.ncl.edu.tw/handle/29338718774482226965.
Texte intégralRésumé :
碩士國立臺北大學
電機工程研究所
99
A power factor correction chip widely used in front-end stage of a power supply system is designed and implemented in the thesis. The power stage uses interleaved boost structure to provide high power factor and to enhance the power density. Moreover, it has a lower input ripple current and shrinks the total volume. Meanwhile the nonlinear solution applied in this chip only needs a current feedback loop and an output voltage sampled loop for modulation purposes. Conventional PFC scheme uses a multiplier that is susceptible to linearity problems can be improved by using an integrator. With an integrator, the duty cycle of pwm signal can be controlled precisely that leads to the total harmonic distortion improvement. The chip solely works with uni-polar supply voltage. It also adopts the leading edge blanking circuit and the over current protection circuit to have a better performance. This chip is fabricated with TSMC 0.35um 2P4M CMOS process.
45
Cai, Kai-cyuan, et 蔡凱全. « Clamp Current Mode Control 'CUK Power Factor Corrector ». Thesis, 2013. http://ndltd.ncl.edu.tw/handle/38534468880916958154.
Texte intégralRésumé :
碩士國立臺灣科技大學
電子工程系
101
This thesis presents an AC-DC converter with negative voltage output. The circuit topology is based on the 'CUK power factor correction converter with inherent voltage step-up/down features. The input and output currents are continuous, low ripple currnet can be achieved. Using UC3842 control IC and the clamp current mode control and voltage-follower control, the studied AC-DC converter has high input power factor. The operating principles for the 'CUK power factor correction converter, clamp current mode control, voltage-follower control, and slope compensation are anlyzed and discussed. Some PSIM simulation results are shown to verify feasibility of the design. An 100W clamp-current-mode control 'CUK power factor correction converter is implemented and tested. The experimental results are fully agreed with the theoretical anlysis.
46
Yeh, Hsiao-I., et 葉孝益. « Control Analysis and Study of Power Factor for Switch-Mode Power Supply Systems ». Thesis, 2003. http://ndltd.ncl.edu.tw/handle/73005238827180620222.
Texte intégralRésumé :
碩士國立清華大學
動力機械工程學系
91
The fast development of high-level computers has promoted the growing demands for switch-mode power supplies with high energy density and efficiency recently. Hence, the switch-mode power supplies operated at high frequency have evidently dominated over the conventional linear power supplies. However, sinusoidal ac currents chopped by the high speed switching devices into current pulses would not only affect the stability of the circuits but also deteriorate the power factor with more energy losses. Thus, the improvement on the power factor of switch-mode power supplies has been the common goal and incentive in the industry. In this thesis, average current control mode has been employed for simulating the complete power circuits with the help of EDA software, namely Pspice, on analyzing circuits and modeling devices such that stability and high power factor can be achieved. Moreover, the paralleling of power supplied has been studied for correcting the power factor with optimized operational regions under power overload conditions. The results are promising for the future applications of simulation in PFC circuits.
47
CHEN, HONG-MING, et 陳宏明. « Micro-computer aided power factor and voltage control for a simulator power system ». Thesis, 1987. http://ndltd.ncl.edu.tw/handle/61518746992646777315.
Texte intégral
48
Lin, Yu-Cheng, et 林祐辰. « A Unity Power Factor Controller of Three-Phase Three-Level Diode Clamped Rectifier under Unbalanced Grid Voltage Source ». Thesis, 2018. http://ndltd.ncl.edu.tw/handle/n8a5bj.
Texte intégralRésumé :
碩士國立臺灣科技大學
電機工程系
106
This thesis proposes an improved unity power factor controller, this controller can improve not only the input current unbalance factor but also the DC-BUS voltage ripple of three-level Neutral Point Clamped (NPC) rectifier works under unbalanced grid source condition. In addition to through the mathematical model of the three-level NPC rectifier and Unity Power Factor controller, we can get the relationship between input current, neutral point voltage and DC-BUS voltage. Hence, as long as we get the mathematical relations, it can be used to balance the neutral point voltage and reduce the neutral point voltage without using neutral point current sensor. The control scheme of this thesis uses MATLAB/SIMULINK simulation software to prove. The experiment establish a 750VDC/2kW, power factor 0.99 of three-level NPC rectifier, and employ digital signal processor TMS320F28069 as a controller to implement, simulation and experiment results shows in this thesis.
49
Chen, Wei-Pang, et 陳維邦. « Implementation of a Boost Power Factor Corrector with Digital Control ». Thesis, 2011. http://ndltd.ncl.edu.tw/handle/4m3tj8.
Texte intégralRésumé :
碩士國立臺北科技大學
電機工程系所
99
The purpose of this thesis is to achieve a high power factor corrector. The circuit uses six switches module, it can realize boost and buck power factor corrector, and the control method is average current control, it uses inner return route to control the current to achieve high power factor converter; also uses outer return route to control the voltage to achieve the output voltage stable without effected by the change of line voltage and load resistance. This thesis analyze the small signal analysis of the inner and outer return route first, inferential reasoning the needed error compensators. Then uses Matlab/ Simulink to build the system model to test the feasibility of designed controllers. Last uses the digital signal processor to control the circuit built by the six switches module to achieve average current control. It would replace the analog elements to achieve the purpose of small volume and high design elasticity. By the experiment, the power factor corrector only raises the power factor from 0.3 to 0.7.
50
Liu, Ming-Song, et 劉明松. « Improvement of Nonlinear Carrier Control ofSingle Active Power Factor Correction ». Thesis, 2006. http://ndltd.ncl.edu.tw/handle/7bhwqe.
Texte intégralRésumé :
碩士國立臺北科技大學
電機工程系所
94
Recently, power electronics have been widely used, thus causing a great number of harmonics to be injected into the grid and hence degrading the quality of the utility. Therefore, power factor correction has been employed to overcome this problem. There are two types of power factor correction, passive and active. The former has larger size than the latter, which is the reason why the active power correction is widely preferred and deeply investigated. In this paper, modification of the nonlinear carrier control of the single active power factor correction is presented and applied to a boost-type converter. Based on this, the harmonics with the proposed feedforward control applied to the nonlinear carrier control are reduced greatly and hence the corresponding power factor is increased significantly. The detailed derivation of the nonlinear carrier control is described herein and then some simulation and experimental results are provided to demonstrate the effectiveness of the proposed control strategy.